Projection Display System

1. Field of the Invention

This invention relates to illumination control systems and, in particular, projection display systems using illumination amplifiers.

2. Description of the Prior Art

Control of illumination has been accomplished in the prior art with mechanical devices. The well known aperture and shutter of a camera are common mechanical devices for controlling light. Other prior art illumination control arrangements are described hereafter.

In the photoplotter field, a photohead is used to control light for exposing film. Mechanically positioned filters and shutters are used for illumination control such as described in U.S. Pat. No. 3,330,182 issued in July 1967.

The prior art is represented in the art of record herein.

The prior art and subsequent art in illumination control is further defined in the art-of-record of the parent application Ser. No. 366,714 including U.S. Pat. No. 3,790,901 to White et al; U.S. Pat. No. 3,778,791 to Lewicki et al; U.S. Pat. No. 3,764,213 to O'Meara; U.S. Pat. No. 3,744,906 to Sato et al; U.S. Pat. No. 3,720,923 to Chen et al; U.S. Pat. No. 3,713,042 to Kinsel; U.S. Pat. No. 3,705,758 to Haskal; U.S. Pat. No. 3,696,344 to Feinleib et al; U.S. Pat. No. 3,670,202 to Paine et al; U.S. Pat. No. 3,558,892 to Seeley; U.S. Pat. No. 3,473,084 to Dodge; and U.S. Pat. No. 3,427,458 to Parfomak et al and in the art-of-record of the parent application Ser. No. 730,756 including U.S. Pat. No. 3,981,002 to Gardner; U.S. Pat. No. 3,798,452 to Spitz et al; U.S. Pat. No. 3,786,486 to Torresi; U.S. Pat. No. 3,707,323 to Kessler et al; U.S. Pat. No. 3,702,723 to Borden Jr.; U.S. Pat. No. 3,700,805 to Hanlon; U.S. Pat. No. 3,666,881 to Stein; U.S. Pat. No. 3,647,959 to Schlesinger et al; U.S. Pat. No. 3,641,264 to Macovski; U.S. Pat. No. 3,627,408 to Fergason; U.S. Pat. No. 3,605,594 to Gerritsen; U.S. Pat. No. 3,576,364 to Zanoni; U.S. Pat. No. 3,566,021 to Jakes Jr.; U.S. Pat. No. 3,544,711 to De Bitetto; U.S. Pat. No. 3,541,254 to Orthuber; U.S. Pat. No. 3,527,879 to Pritchard; U.S. Pat. No. 3,444,316 to Gerritsen; U.S. Pat. No. 3,231,746 to Goodrich; and U.S. Pat. No. 2,169,838 to Herbst which are herein incorporated-by-reference. The prior art in illumination control is still further defined in the art-of-record of the referenced related applications including U.S. Pat. No. 3,836,916 to Wiley; U.S. Pat. No. 3,721,164 to Kuttigen; U.S. Pat. No. 3,703,858 to Canfora; U.S. Pat. No. 3,695,154 to Webster; U.S. Pat. No. 3,686,675 to Faul; U.S. Pat. No. 3,648,578 to Ritchie; U.S. Pat. No. 3,610,119 to Gerber; U.S. Pat. No. 3,595,147 to Blattner; U.S. Pat. No. 3,565,524 to Pabst et al; U.S. Pat. No. 3,498,711 to Ables et al; U.S. Pat. No. 3,458,253 to Hansen; U.S. Pat. No. 3,354,806 to DeLang et al; U.S. Pat. No. 3,330,182 to Gerber et al; U.S. Pat. No. 3,323,414 to Ritchie et al; and U.S. Pat. No. 3,048,093 to Loro.

The present invention provides a projection display system for improved control of illumination. This illumination control system can use solid state devices for electronic control of illumination, with reduced dependence on mechanical control devices.

Illumination amplifiers are provided which control the transmissivity-reflectivity characteristic as a function of applied excitation. Such amplifier devices may be controlled in a digital fashion or in an analog fashion using electronic signals for control of illumination. Also, servo arrangements are provided for precise control of illumination.

Availability of a basic illumination processing component, the illumination amplifier, permits a wide variety of illumination processing systems to be implemented. These systems include illumination computers of both the digital and the analog variety, photographic cameras, photoplotter systems, illumination controls for vehicles such as automobiles, light and heat control systems for inhabited structures, and other such illumination systems.

Various control configurations may be provided including open and closed loop controls, analog and digital controls, illumination amplifier excitation arrangements, and other control configurations.

An object of this invention is to provide an improved illumination control system.

A further object of this invention is to provide a solid state illumination control system.

Another object of the present invention is to provide an improved large screen projection display system.

Another object of the present invention is to provide an improved high intensity projection display system.

Another object of the present invention is to provide an improved color projection display system.

Another object of the present invention is to provide an improved projection television display system.

Another object of the present invention is to provide an improved projection billboard display system.

Another object of the present invention is to provide an improved projection scoreboard display system.

Yet a further object of this invention is to provide illumination computer arrangements including both analog and digital illumination arrangements.

Another object of this invention is to provide improved excitation and control devices for illumination amplifier arrangements.

Yet another object of this invention is to provide illumination closed loop servos for precision control.

Still a further object of this invention is to provide an improved display arrangement.

Yet another object of this invention is to provide an improved illuminated switch arrangement.

Yet still another object of this invention is to provide improved chopper, scanner and modulator arrangements.

Still another object of this invention is to provide improved photographic control arrangements.

Still another object of the present invention is to provide an improved projection display arrangement.

Still another object of the present invention is to provide an improved heat transfer arrangement.

Still another object of the present invention is to provide an improved large panel arrangement.

The foregoing and other objects, features, and advantages of this invention will become apparent from the following detailed description of preferred embodiments of this invention, as illustrated in the accompanying drawings.

A better understanding of the invention may be had from a consideration of the following detailed description taken in conjunction with the following drawings, in which:

FIG. 1 is a block diagram of an illumination control arrangement in accordance with the present invention.

FIGS. 2a-2d illustrates various excitation arrangements for illumination amplifiers in schematic and waveform diagrams comprising FIG. 2A showing a digital excitation arrangement, FIG. 2B showing pulse modulation waveforms, FIG. 2C showing an analog excitation arrangement, and FIG. 2D showing pulse width modulation waveforms.

FIGS. 3A-3F illustrate illumination arrangements in schematic and block diagram form comprising FIG. 3A showing a generalized control network, FIG. 3B showing operation of a single illumination amplifier, FIG. 3C showing an exclusive-OR and coincidence logical arrangement, FIG. 3D showing a flip-flop logical arrangement, FIG. 3E showing an analog exponential arrangement, and FIG. 3F showing an analog implicite servo arrangement.

FIG. 4 is a schematic diagram of a batch fabricated illumination control arrangement.

FIG. 5 is a schematic and block diagram illustrating a closed loop control for an illumination amplifier arrangement.

FIGS. 6A-6E illustrates display arrangements in schematic, waveform, and block diagram form comprising FIG. 6A showing a batch fabricated display arrangement, FIG. 6B showing a batch fabricated illuminated switch arrangement, FIG. 6C showing an illuminated switch schematic diagram, FIG. 6D showing a control arrangement for colored illumination, and FIG. 6E showing pulse modulation control waveforms.

FIGS. 7A-7D is a schematic and block diagram illustrating illumination control arrangements for buildings and for vehicles comprising FIG. 7A showing a first window and a louver illumination control arrangement, FIG. 7B showing a second window illumination control arrangement, FIG. 7C showing an artificial illumination control arrangement, and FIG. 7D showing a temperature control arrangement.

FIGS. 8A-8D are schematic and block diagrams illustrating illumination control arrangements for camera systems comprising FIG. 8A showing an image rotation arrangement, FIG. 8B showing a square aperture arrangement, FIG. 8C showing a circular aperture arrangement, and FIG. 8D showing an illumination control arrangement for a camera.

FIGS. 9A-9C are schematic and block diagrams illustrating a cameral control system in accordance with the present invention comprising FIG. 9A showing a detailed camera control arrangement, FIG. 9B showing a computer control arrangement, and FIG. 9C showing a special purpose control arrangement.

FIG. 10 is a schematic and block diagram illustrating a photoplotter system in accordance with the present invention.

FIG. 11 is a schematic and block diagram illustrating a display system in accordance with the present invention.

FIGS. 12A-12E are schematic and block diagrams illustrating an illumination scanner, chopper, and modulator system in accordance with the present invention comprising FIG. 12A showing a first electro-optical embodiment, FIG. 12B showing a second electro-optical embodiment, FIG. 12C showing a first control embodiment, FIG. 12D showing a second control embodiment, and FIG. 12E showing a third electro-optical embodiment.

FIG. 13 is a schematic and block diagram illustrating an interspersed array of electro-optical elements for illumination control.

FIGS. 14A-14F are schematic and block diagrams illustrating a projection display arrangement comprising FIG. 14A showing a single projector arrangement, FIGS. 14B through 14E showing multiple image projection arrangements, and FIG. 14F showing a TV projection embodiment.

FIGS. 15A-15D are schematic and block diagrams illustrating spacial control comprising FIG. 15A showing a rectangular symetry arrangement, FIG. 15B showing a circular symetry arrangement, FIG. 15C showing a watch embodiment, and FIG. 15D showing a camera control embodiment.

FIGS. 16A-16G are structural arrangements illustrating alternate embodiments of a projection illumination amplifier arrangement, heat transfer arrangement, and large panel arrangement comprising FIG. 16A showing a general heat transfer arrangement, FIG. 16B showing a picture frame heat transfer arrangement, FIG. 16C showing an edge heat transfer arrangement, FIG. 16D showing a reflective mode back-mounted heat transfer arrangement, FIG. 16E showing heat transfer devices, FIG. 16F showing a projection display system employing various heat transfer arrangements, and FIG. 16G showing various heat transfer and large panel construction features in accordance with the present invention.

FIGS. 17A-17E are block and schematic diagrams arrangement showing pulse modulated and display arrangements comprising FIG. 17A showing a pulse modulation circuit, FIG. 17B showing a pulse modulation program flow diagram, FIGS. 17C and 17D showing a liquid crystal display arrangement, and FIG. 17E showing a liquid crystal toy.

Material pertinent to the figures has been cancelled and incorporated by reference from parent U.S. Pat. No. 3,986,022 which is incorporated herein by reference.

By way of introduction of the illustrated embodiment, the components shown in FIGS. 1 through 17 of the drawings have been assigned general reference numerals and a brief description of such components is given in the following description. The components in FIGS. 1-16 have in general been assigned three or four digit reference numerals wherein the hundreds digit of the reference numerals corresponds to the figure number. For example, the components in FIG. 1 have reference numerals between 100 and 199 and the components in FIG. 2 have reference numerals between 200 and 299 except that the same component appearing in successive drawing figures has maintained the first reference numeral. The components in FIG. 17 has not been numbered as discussed above, but has been assigned 900 series reference numerals to be consistent with the corresponding figure in the referenced copending applications.

The illumination control system of this invention can take any of a number of possible forms. Preferred embodiments of several features of the present invention are shown in the accompanying figures and will be described in detail hereafter.

The system of this invention is exemplified by the simplified block diagram shown in FIG. 1. An illumination source 100 generates illumination 102 which is directed to an illumination amplifier 104. The illumination 102 from the source 100 may be defined as source illumination. Source illumination 102 may be raw illumination or may be controlled by source illumination control devices such as will be described hereafter. Illumination amplifier 104 may be a variable illumination transmissivity device such as a well known liquid crystal device. Controlled illumination 106 from illumination amplifier 104 is directed to illumination receiver 112. This controlled illumination 106 may be controlled by reflection, transmission, or by other characteristics of illumination amplifier 104. Also, controlled illumination 106 may comprise a plurality of illumination signals such as one or more reflected components and one or more transmitted components, where one of these illumination components 108 may perform a first illumination task such as exposing an illumination sensitive medium which may be receiver 130 and another of these illumination components 110 may perform a second illumination task such as illuminating an illumination sensitive feedback transducer which may be receiver 134. One arrangement comprising control of a plurality of illumination signals will be discussed hereafter with reference to FIGS. 3, 4, and 5.

Illumination receiver 112 may include an arrangement for illuminating an illumination sensitive medium 130 such as a film and may include a feedback transducer 134 for providing feedback signal 114 for control of illumination.

Illumination feedback signals 114 may be used to control illumination amplifiers 104, may be used to control illumination sources 100 and may be used as feedback to command devices 127. Feedback signal processor 116 provides signal processing for feedback signals 114 and may include illumination amplifier feedback signal processor 118 for generating an illumination amplifier feedback signal 120 for control of illumination 106 by amplifiers 104 with processed command signals 133; may further include illumination source feedback signal processor 122 for generating illumination source feedback signals 124 for control of illumination 102 by source 100 with processed command signals 132; and may still further include illunination command device feedback signal processor 138 for generating illumination command device feedback signals 139 for control of command signals 126 by command devices 127.

Illumination command signal 126 may be open loop or closed loop input commands from command devices 127. Such a command device may be a manual device for operator control such as a switch arrangement or may be an automatic device such as a digital computer, an analog computer, or other such well known command arrangements. Command signal processor 128 may generate illumination source command signals 132 to command source 100 to generate source illumination 102; or may generate illumination amplifier command signals 133 to command amplifier 104 to control illumination 106; or both.

Discussion entitled Illumination Amplifier Devices, Digital Excitation, Analog Excitation, Schematic Notation, Illumination Computer, Digital Control Arrangements, Analog Control Arrangements, Batch Fabricated Arrangement, Closed Loop Control, Flat Plane Configuration, Discrete Illunination Device, Light Pen Arrangement, Illumination Switches, Color Control, Control of Natural Illunination, Illumination Control For Buildings, Illunination Control For Vehicles, Illunination Shade, Temperature Control, Control Of Artificial Illumination, Lamp Control, Dimmer Control, Flasher Control, Camera Systems, Image Rotation Control, Aperture Control, Shutter Control, Photographic Camera System, Source Illumination Control, and Audience Display System are provided in referenced parent application Ser. No. 366,714 at page 10 line 1 to page 109 line 32 therein; which is now U.S. Pat. No. 3,986,022 having such disclosures at column 5 line 16 to column 55 line 27 therein; and which is herein incorporated by reference therefrom as if fully set forth at length herein. Discussions on projection illumination amlplifier arrangements, lens and illumination amplifier combinations, and illumination amplifier coherent illumination are provided in referenced parent application Ser. No. 366,714 at FIGS. 6D and 8 to 10, page 26 lines 19 to 32, page 61 lines 13 to 18, page 62 lines 7 to 9, page 84 line 1 to page 96 line 22, page 122 lines 30 to 34, page 113 lines 9 to 25, and elsewhere therein; which is now U.S. Pat. No. 3,986,022 at FIGS. 6D and 6 to 10,

The illumination amplifier feature of the present invention provides an improved means and method for chopping, scanning, and modulating illumination. Prior art devices tylpically involve rotating mirrors or CRT flying spot scanners, as discussed in the articles (1) Optical Scanners; Comparisons and Applications by Compton published in the February 1976 issue of Electro-Optical Systems Design and (2) Laser/Galvo Scanner Design by Tenney et al published in the October 1975 issue of Electro-Optical Systems Design magazine at pages 40-45 and herein incorporated-by-reference. The illumination amplifier feature of the present invention can provide further advantages in combination with prior art devices. For example, the reflective surfaces used in many prior art electro-mechanical scanners can be replaced by the illumination amplifier arrangement of the present invention to provide electro-optical control in place of or in addition to prior art electro-mechanical control. Still further advantages may be achieved with a fully solid-state illumination control scanner, chopper, or modulator device as discussed below with reference to FIGS. 12A-12C.

An illumination amplifier device is shown in FIG. 12A that may be used as an optical scanner, chopper, or modulator. Illumination amplifier segments 1210-1217 may be individually controlled such as to be either reflective or transmissive in response to electrical control signals. Illumination signal 102, shown incident upon scanner 1200, is transmitted by segments controlled to be transmissive such as with illumination 102 transmitted through segment 1210 to illuminate sensor 134.

Illumination 102 may be chopped by selectively controlling segments 1210-1217 to be sequentially or randomly transmissive and reflective. A sequential rotary scan will now be described for simplicity although other non-sequential scans may be provided. In the rotary scan, one and only one segment is controlled to be transmissive, wherein each of the segments is sequentially controlled to be transmissive. For example, segment 1210 may be transmissive and segments 1211-1217 may be controlled to be reflective, then segment 1211 may be controlled to be transmissive and segments 1210 and 1212-1217 may be controlled to be reflective, then segment 1212 may be controlled to be transmissive and segments 1210-1211 and 1213-1217 may be controlled to be reflective etc as shown in the table listing Sequential States. This table lists the repetitive sequence of scanner states and the transmissive and reflective segments for each state.

After a complete scan with all segments, the scan may continue sequentially from segment 1217 to segment 1210 and repeat the sequence. This rotating scan concept is analogous to the well-known mechanical rotating chopper used on astrotrackers such as the Kollsman KS-50 astrotracker and other angular positioning devices.

A solid-state scanner will now be described with reference to FIG. 12B using illumination amplifier devices. In the prior art, scanner arrangements use oscillating or movable mirror arrangements such as used in the Zerox electrostatic copier machine, where a mirror is rotated or oscillated to scan a document for printing purposes. Other mechanical scanner arrangements are well known in the art. Problems exist with such prior scanners, where electro-mechanical scanners traverse a fixed scan cycle due to inertial characteristics and where the optical output may be "smeared" due to the continuous motion of the mechanical scanner. A solid-state electro-optical scanner in accordance with the present invention provides discretely selectable conditions selectable under electronic control independent of inertia and other such sequential characteristics thereby permitting random scan arrangements and virtually any scan sequence. Further, the scanner arrangement in accordance with the present invention permits discrete scan position to be selected and maintained, thereby providing a continuously changing image to the illumination destination and minimizing the blur or smearing effect of a continuous scan. The scanner of the present invention will be exemplified with a simple description to exemplify the inventive features. It is intended that this simple description be interpreted in a broad form to include more complex scanning arrangements such as having a greater number of scan positions, using devices other than the liquid crystal devices, being constructed with other techniques, providing continuous scanning in contrast to discrete scanning, and incorporating the various other teachings of this inventive feature.

For simplicity, this generalized scanner concept will be discussed for a multi-layered liquid crystal embodiment although other configurations will become obvious from the teachings thereof. A glass substrate 1222 may be composed of many layers of glass at different angles 1221 all stacked and bonded together and containing liquid crystal illumination amplifiers therebetween such as with well-known etched electrodes and liquid crystal material in each layer interface 1230-1237. Scanning is achieved by sequentially selecting different layers having different reflective angles to be reflective thereby reflecting illumination to or from different locations. For example, if device 1224 is an illumination sensor, scanner 1220 will sequentially detect illumination from illumination paths 1240-1247 as the scanning progresses along path 1223. Alternately, device 1224 may be an illumination source where an illumination signals 1240-1247 may be scanned across element 1223 for selective illumination. Illumination signals from a source 1224 may be further processed with well-known electronics. For example, illumination signals 1240-1247 may be accumulated with lens systems after illuminating scanned element 1223 for processing with illumination sensors.

In accordance with FIG. 12B, a plurality of illumination amplifier devices may be arranged having a depth dimension into the support medium such as a glass medium for liquid crystal devices, wherein the illumination must traverse transmissive illumination amplifier elements until it reaches a reflective element. For example, if a first element 1230 closest to the surface is reflective, illumination will be reflected in a direction 1240 determined by this surface element, and if the first element 1230 closest to the surface is transmissive, illumination will be transmitted to a second amplifier 1231 next closest to the surface through the first transmissive element 1230. If the second element 1231 is reflective, illumination will be reflected in a direction 1241 determined by this second element 1231 which is the first reflective element, and if the second element 1231 is transmissive, illumination will be transmitted to a third amplifier 1232 next closest to the surface through the first two transmissive amplifier elements 1230 and 1231 and so forth until the illumination is incident upon a first amplifier having a reflective characteristic. This first amplifier having a reflective characteristic will determine the selected angle of the scanner. Therefore, the illumination from the source may be transmitted through a plurality of illumination amplifiers that are non-reflective until incident upon the first illumination amplifier that is reflective, thereby electro-optically selecting the particular scanner angle.

For simplicity of discussion, a sequential scanning arrangement of scanner 1220 will now be discussed. For simplicity of illustration, it shall be assumed that one and only one amplifier layer 1230-1237 of layers 1221 is controlled to be reflective and all other amplifier layers are controlled to be transmissive although other scans may be provided to make combinations of elements 1230-1237 reflective and transmissive. For a sequential scan, illumination amplifier 1230 is first controlled to be reflective thereby generating reflective illumination signal 1240, then amplifier 1230 is controlled to be transmissive and amplifier 1231 is controlled to be reflective thereby generating reflective illumination signal 1241, then amplifiers 1230 and 1231 are controlled to be transmissive and amplifier 1232 is controlled to be reflective thereby generating reflective illumination signal 1242, etc. The sequential scan may proceed as shown in the table listing Scan States. This table lists the repetitive sequence of scanner states and the transmissive and reflective elements for each state.

When the last amplifier 1227 is controlled to be reflective to generate illumination signal 1247, then scanner 1220 may be controlled to "retrace" by making amplifier 1230 again reflective and thereby retracing from signal 1247 to signal 1240 to start a new scan along element 1223.

An alternate embodiment is illustrated with the following Alternate Scan States table.

Many other alternate embodiments may be provided from the teachings herein.

The scanner inventive feature described above may be characterized as selecting a sequence of elements having different reflective angles to select each of a plurality of sources of illumination (or to select each of a plurality of destinations of illumination) having different angles of incidence (or having different angles of reflection) to provide substantially a constant reflective angle (or incidence angle) to provide reflected illumination to a sensor (or from a source). Other characterizations may include a solid-state scanning device, an electro-optical device for scanning a plurality of sources of illumination to provide scan illumination to a receiver, and a plurality of illumination amplifier devices each having different angular positions for selecting different sources of illumination for reflecting selected illumination to a receiver device.

The illumination amplifier scanner of the present invention may take many forms, where one form is a plurality of individual discrete illumination amplifier elements arranged at different angles. Another form may be provided as a batch fabricated illumination amplifier as shown in FIG. 4 where a plurality of illumination amplifier surfaces such as surfaces 440 and 457 may be sequentially selected to reflect (or transmit) different source images to a common receiver element. Still another embodiment may be a planner arrangement such as illustrated in FIG. 6A, where amplifier elements 602-605 may each be provided having a different angle and where each may be selected in sequence to be reflective to reflect different images to a common destination element. Other scanner embodiments may be arranged as concentric squares and circles as illustrated in FIGS. 8B and 8C, wherein each segment may be arranged at a different angular position. Other configurations may be provided such as determined by convenient manufacturing methods to provide a plurality of illumination amplifiers having different angular positions therebetween in accordance with the teachings of the scanner feature of this invention.

A multi-dimensional scanner arrangement may be provided having a two-dimensional angular orientation between a plurality of illumination amplifier elements. In one batch fabricated arrangement, a spherical surface may be provided having facets arranged about the surface of the spherical device having different orientations in two dimensions.

One optical scanner in accordance with the present invention may be characterized as a single photosensor with a plurality of electronically controlled amplifier elements each selecting a particular source or direction for reflecting to the single photosensor. The photosensor and associated electronics may be considered as being time-shared between a plurality of source elements selectable with the illumination amplifier elements.

The scanner feature of the present invention may be usable in place of present well-known scanner arrangements including the rotating mirror associated with a Zerox copy machine, the rotating mirror and photocell arrays associated with optical character recognition systems, a Vidicon and other tube scanners associated with television cameras, flying spot scanners, and other well-known scanning devices.

Scan control may be provided with the relatively simple counter and decoder arrangement of FIG. 12C or may be provided with higher capability electronics such as a digital computer controlled scan. In order to exemplify this feature of the present invention, a simple sequential scan arrangement will be discussed with reference to FIG. 12C. Sequential scanning may be controlled with binary counter 1204 being repetitively sequenced through eight counts under control of clock signal CK. The sequential binary count from counter 1204 may be decoded with decoder 1205 to generate one of eight control signals B0-B7 in response to the three binary encoded signals B, C, and D from counter 1204. Each of the eight control lines from decoder 1205 may be used to control a different amplifier segment of scanner 1200 (FIG. 2A) and a different amplifier level of scanner 1220 (FIG. 2B). For example, decoder output signals B0-B7 may control amplifier segments 1210-1217 respectively of scanner 1200 and may control amplifiers 1230-1247 respectively of scanner 1220. As counter 1204 sequences through the binary count, decoder 1205 sequences through the eight control signals B0-B7; wherein the selected control signal from decoder 1205 will cause the related segment of scanner 1200 to become transmissive (operating in the transmissive mode) and will cause the related amplifier of scanner 1220 to become reflective (operating in the reflective mode). Counter 1204 and decoder 1205 may be well-known Texas Instruments S/N 7400 integrated circuit logic wherein counter 1204 may be an S/N 7491 counter and decoder 1205 may be a S/N 7445 decoder.

For simplicity of discussion, mutually exclusive control has been described where one and only one segment of scanner 1200 is controlled to be transmissive and one and only one amplifier of scanner 1220 is controlled to be reflective, but many other combinations can be provided. For example, scanning may be random in nature for adaptive scanning or may be selective in nature to select a particular segment or angle without traversing a sequential scan. Further, various combinations of segments and amplifiers may be controlled to be transmissive or reflective.

For further simplicity of discussion, the angular dimensions and resolution of amplifier segments 1210-1217 and amplifiers 1230-1237 are shown in exaggerated form. In other embodiments, the segments of scanner 1200 may have fine angular resolution such as 1024 segments being used instead of the eight segments of the present example. Further, the angles of amplifiers 1230-1237 of scanner 1220 may have greater resolution such as 1024 scanning angles in place of the eight angles of this example. Still further, the interchangability of the reflective and transmissive modes as discussed above permits the scanners to operate in either the reflective or transmissive mode. For example, scanner 1200 has been discussed for transmissive mode operation and scanner 1220 has been discussed for reflective mode operation, where alternately scanner 1200 may operate in the reflective mode and scanner 1220 may operate in the transmissive mode.

Still further, control may be provided in analog form wherein amplifiers 1210-1217 of scanner 1200 and amplifiers 1230-1237 of scanner 1220 may be controlled to be partially reflective and partially transmissive such as by using the pulse modulated control arrangement discussed with reference to FIG. 2.

Yet further, an analog scan may be provided by implementing continuously variable controls such as discussed in U.S. Pat. No. 3,675,988 to Soref, which is herein incorporated-by-reference, thereby providing a continuous scan in contrast to the discretely stepped scan discussed with reference to FIGS. 12A-12C.

A closed loop adaptive scanner embodiment will now be discussed with reference to FIG. 1. Command device 127 may be an adaptive command device such as a stored program digital computer or may be other well-known adaptive command devices. Command device 127 generates command signal 126 to the command signal processor 128, as previously discussed with reference to FIG. 1. Control signals 133 to amplifier 104 may control amplifiers 1210-1217 and amplifiers 1230-1237 (FIGS. 12A and 12B), wherein these amplifier elements are included in the general amplifier block 104. Illumination transmitted or reflected to illumination detectors as shown in FIG. 12 corresponds to illumination 110 to sensor 134 (FIG. 1). Sensor signal 114 may be communicated to adaptive device 127 as signals 139 for adaptive control. Command device 127 may command scanning or monitoring with a single amplifier angle and may adaptively change the monitored angle to optimize the feedback signal 139. Adaptive control with feedback to a digital computer is discussed in applications Ser. No. 134,958 and Ser. No. 135,040 for a machine control system and are equally applicable to the illumination control system of the present invention.

A specific use of the electro-optical chopper of the present invention will now be discussed in detail to exemplify the more general features of the present invention.

Mechanical chopper arrangements are well known in the prior art such as illumination choppers used for startrackers such as the Kollsman Automatic Astro Compass type KS-50-03. Such prior art devices provide a rotating mechanical shutter that permits incident light to be transmitted or blocked as a function of the angular position of the incident light and the phase of the mechanical shutter rotation.

In accordance with the teachings of the present invention, an illumination amplifier chopper may be provided using amplifiers 104 controlled by signals 133 to chop illumination 102 to generate chopped illumination 106. Amplifiers 104 may be arranged with segments having a particular orientation, discussed with the reference to FIG. 12A. Control signals 133 select the various segments in sequence, which may be a clockwise or counter-clockwise sequence as with the mechanical choppers or, in a preferred embodiment, may select the segments in a random access sequence such as may be defined under control of command devices 127 which may include a computer 251.

In a preferred mode of operation, an initial acquisition scan such as a complete clockwise scan using all segments may be performed to initially locate an image. After an image has been located, only segments closely associated with the image location may be scanned in an adaptive manner to increase the duty cycle of the chopped signal and to decrease the re-acquisition time. This adaptive capability provides significant advantages over prior art mechanical chopper arrangements, where mechanical choppers and other sequential devices do not provide selective or random access illumination chopping capabilities. The electronic control arrangement of the present invention permits external illumination to be chopped in almost any desired random order or sequence based upon optimizing the particular system considerations.

In contrast to prior art illumination chopper systems, the system of the present invention provides null seeking capability with a computer contained in command devices 127 (FIGS. 1 and 9B) for commanding the selective chopping of illumination with amplifiers 104 under control of command signals 126 to command signal processors 128 to generate control signals 133 to provide chopped illumination 106. Transducer 134 generates feedback signals 114 to signal processors 116, where computer 251 in command devices 127 is responsive to feedback signals 139 to determine the location of the illumination. Computer 251 and command devices 127 control the system to center the illumination such as by controlling a gimballed startracker to reposition the image in the telescope, as is well known in the art. Computer 251 would continually adjust such a controlled arrangement to center the illumination in response to the chopped feedback signals until incident illumination is centered, indicative of equal feedback signals when each of the illumination amplifier segments 104 were selected by computer 251.

In one embodiment of the scanning arrangement shown in FIG. 12A, digital counter 1204 included in command devices 127 generates binary output signals 1206 included in signals 126 to decoder 1205 included in command signal processor 128. Decoder 1205 decodes binary inputs signals 1206 to generate individual select output signals B0-B7 which sequentially select segments 1210-1217 or 1230-1237 to chop input illumination 102 to generate chopped output illumination 106 to illuminate transducer 134. The output of transducer 134 excites signal condition devices 116 to generate feedback signal 139 such as by loading the output of counter 1204 into the computer when the chopped signal 106 illuminates transducer 134. Therefore, the number loaded into the computer is indicative of the segment of chopper 104 upon which illumination 102 is projected, where the number loaded into the computer is indicative of the direction in which illumination 102 is off from the center 1201 of the chopper.

The number loaded into the computer may be used to identify the off-center condition of illumination 102 to process information, or to control the system, or both in response thereto using well-known prior art arrangements.

Chopper arrangement 1200 is shown in a simplified embodiment in FIG. 12A to exemplify the present invention. It will become obvious from the teachings of the present invention that more sophisticated arrangements may be configured, where the computer may directly or indirectly generate select signals B0-B7 in either a sequential form as described above or in a random access form to select particular segments in order to optimize system considerations.

Further, a computer may receive feedback signal 139 as a discrete input signal as described in the referenced copending applications to identify the segment illuminated by illumination 102. In one embodiment, computer 251 in command device 127 and command signal processor 128 may replace counter 1204 and decoder 1205 to generate select signals B0-B7 in a preferred sequence or in a random manner and may monitor output signal 139 of sensor 134 to determine the off-center direction of illumination 102. In another embodiment, the computer may select a particular segment 1210-1217, then monitor signal 139 to determine the illumination condition, then continue to interrogate the various segments 1210-1217 and, in conjunction with each interrogation, monitor signal 139 to determine the off-center direction of illumination 102. In still another embodiment shown in FIG. 9B, computer 251 may receive feedback signal 139 as a whole number digital signal from an analog-to-digital converter 138 included in feedback signal processor 116 to define the relative amplitude of illumination intensity.

In yet another feedback embodiment discussed with reference to FIG. 12C, sensor 134 (also shown in FIG. 12A) may receive chopped illumination 106 (FIG. 12A) and may generate feedback signal 114 to C-Register 1207 to load output signals 1206 from counter 1204 into C-Register 1207 in response to feedback signal 114. The contents of C-Register 1207, indicative of the angular position of incident illumination 102 (FIG. 12A) may be loaded into computer 251 for control of scanner 1200 and for control of other system operations. Loading of C-Register 1207 and communication between C-Register 1207 and computer 251 is discussed in the referenced applications, particularly in application Ser. No. 291,394.

Mechanical scanners are well known in the art and interfacing thereof may be used to interface the electro-optical scanner of the present invention.

A preferred arrangement for interfacing chopper 1200 with an electronic system such as with a computer will now be discussed with reference to FIGS. 12A and 12C. Chopping of illumination signal 102 to obtain chopped illumination signal 106 provides a phase relationship that determines the direction of offset of illumination 102 from being focused directly on the center 1201 of scanner 1200. Sensor 134 generates output pulse 114 when chopped illumination 106 illuminates sensor 134. This condition occurs when counter 1204 commands the segment that is illuminated by the off-center illumination, which is segment 1210 in the example shown in FIG. 12A, to be transmissive thereby illuminating sensor 134 with chopped illumination 106. Therefore, the state of counter 1204 when sensor 134 detects chopped illumination 106 identifies the segment transmitting the chopped illumination 106 and therefore identifies the direction of the incident illumination 102. The mechanization shown in FIG. 12C can provide feedback to an electronic system where sensor 134 generates output signal 114 when counter 1204 controls the segment having the incident illumination 102 transmitted thereon to be transmissive. Therefore, sensor signal 114 (FIG. 1) may be used to control loading of signals 1206 from counter 1204 into C-register 1207 for storing identification of the segment related to the direction of incident illumination 102. C-register 1207 may then be used as an interface register between scanner 1200 and an electronic system which may include a computer 251 (FIGS. 2C, 9B, and 12C).

The electronic system interface may be better understood relative to the disclosures in the referenced copending applications. For example, the C-register interface with a computer is discussed in detail in application Ser. No. 101,881; particularly with reference to FIG. 13 therein showing C-register 260. Further, a preferred embodiment of the C-register is discussed in application Ser. No. 291,394 particularly with reference to FIG. 7 therein. Said FIG. 7 shows C-register 460 being loaded with input signals 708 in response to load strobes DC-7 and DC-3 and the transfer of the loaded information from C-register 460 to A-register 706 in computer 112 as discussed therein, where strobe DC-7 may be output signal 114 from sensor 134 discussed herein and in application Ser. No. 366,714. Still further, a sequence of control signals may be generated in response to an input signal with the mechanization disclosed in application Ser. No. 302,711; particularly with reference to FIG. 5 therein; wherein input signal 283 is processed with digital electronics to generate a sequence of clear signal 506 and enable signal 508 which may be used to clear and load the C-register; as discussed above for FIG. 7 of application Ser. No. 291,394; in response to the input signal 114 from sensor 134. Alternately, computer 251 may directly monitor output signal 114 of sensor 134 such as with a skip-on-discrete instruction and may directly control transmissivity and reflectivity of segments 1210-1217 such as by using the C-register discussed above as an output register.

An alternate embodiment wherein the computer is included in the feedback loop will now be discussed with reference to FIG. 12D. Computer 251 packs together a combination of one bits and zero bits in the internal A-register, wherein each packed bit corresponds to a different segment 1210-1217 of scanner 1200 and wherein a one state may define transmissivity and a zero state may control reflectivity for the corresponding segments 1210-1217. Such operations may be performed with well-known table lookup and packing operations. Computer 251 may then output the packed discrete word from the A-register to the interface C-register 1207, wherein the packed discrete conditions B0-B7 are stored in C-register 1207 to control segments 1210-1217 of scanner 1200. Computer 251 packs together and outputs a new control word B0-B7 to C-register 1207 for every scan increment such as for each desired change in transmissivity and reflectivity of one or more segments 1210-1217; which may be sequential changes implemented with well-known counting, polling, and/or indexing programming methods. Incident illumination 102 is conditionally transmitted or chopped by scanner 1200 to generate chopped illumination 106 to illuminate sensor 134. Sensor output signal 114 may be sensed directly by computer 251 such as with a skip-on-discrete instruction. Computer 251 may either sequentially scan, randomly scan, or adaptively scan illumination 102 by monitoring feedback signal 114 to identify the direction or other characteristics of incident illumination 102. Therefore, computer 251 in the scanning loop may reduce special purpose electronics and may provide flexibility and adaptive control. A preferred embodiment of such a computer is discussed in application Ser. No. 101,881; where the preferred embodiment includes a read only memory and a scratch pad memory in a micro-computer type configuration.

For simplicity of discussion, illumination signals between element 1224 and scanner 1222 are shown at different angles indicated by signal paths 1240-1247. These signals 1240-1247 inbetween scanner 1222 and generator 1224 may actually be colinear, parallel, or have other such relationships.

A scanner embodiment may be used for display purposes, wherein this scanner inventive feature will now be discussed with reference to FIG. 12B. In this embodiment, element 1223 may be a multi-character display and may be a frosted glass screen or other projection device and element 1224 may be a character generator such as a single liquid crystal character being controlled from well-known digital display electronics. Refresh electronics such as discussed in applications Ser. No. 101,881 and Ser. No. 288,247 may be used to display a sequence of characters with character generator 1224. The sequence of characters may be scanned onto element 1223 into sequential locations shown being illuminated by illumination signals 1240-1247. For example, time-shared character generator 1224 may be controlled to repetitively generate a set of eight sequential characters wherein sets of these eight characters may be continuously and repetitively refreshed or generated. As each character is sequentially generated, a related illumination amplifier 1230-1237 may be controlled to project the related character onto element 1223 in the desired position. In a preferred embodiment, each sequential character of the set generated with generator 1224 corresponds to a different scanner element 1230-1237 and therefore a different projection location identified with illumination signals 1240-1247; wherein character generator 1224 and scanner segments 1230-1237 may be correspondingly controlled in the sequential character generation and scanning process. For example, a first character of the set may be generated in combination with the first scanned segment 1230 being selected to project the first character in the set onto the location of project screen 1223 defined by illumination signal 1240. Correspondingly, as each of the set of eight characters is sequentially generated with generator 1224, one of the scanner segments 1230-1237 is selected for the corresponding character. This can be seen with reference to the scan table discussed above, wherein each sequential scan signal B0-B7 may select a different control signal or character to be projected along the appropriate illumination signal path of signal paths 1240-1247 respectively. During the repetitive scan cycle, the B0 control signal or character will always be projected with illumination signal 1240 as controlled with the scan mechanization discussed above relative to FIGS. 12C and 12D. Therefore, scanner 1220 of the present invention may be used to time share a single-character display to provide a multiple-character display; thereby providing a low-cost and efficient multiple-character display.

Display generator 1224 may be a very small display generator such as a miniature liquid crystal display character and operator display 1223 may be a large display such as an audience display. Proper introduction of well-known optics such as magnifying lenses inbetween display generator 1224 and scanner 1222 or inbetween scanner 1222 and screen 1223 may permit use of a small character generator 1224 and a large screen 1223.

Another feature of the present invention illuminates generator 1224 with a high intensity floodlight 1225, where this floodlight is shown illuminating generator 1224 in a transmissive mode but similarly may be used in a reflective mood. High intensity illumination of a small generator 1224 may be used in combination with magnification optics such as magnifying lenses placed inbetween generator 1224 and projection screen 1223 to provide high intensity large screen displays with a miniature character generator 1224 using low power electrical control signals to control or modulate high intensity illumination from floodlight 1225 in an illumination amplifier configuration. Further, generator 1224 may generate other symbols than characters such as a spot of light, a schematic symbol, or other such symbols. In such an embodiment, system 1220 may be used as a photo-plotter or display, wherein element 1223 may be an illumination sensitive medium such as film for permanent recordings, may be a frosted glass screen or a frosted coating for temporary displays, or may be other types of illumination sensitive or projection devices.

Scanners 1200 and 1220 are discussed above as single-dimension scanners for simplicity of illustration. It is herein intended that the teachings discussed with reference to FIG. 12 be interpreted as exemplifying multi-dimensional scanning capability. For example, the angular representations of elements 1230-1237 shown in a single-dimensional configuration may be similarly shown in a multi-dimensional configuration for scanning illumination signals in a plurality of dimensions. For example, linear screen 1223 may be replaced with a two-dimensional screen such as used in a television receiver and the signals may be scanned in various well-known patterns such as a raster scan used in a conventional TV receiver. Alternately, other well-known scans may be used such as radar related scans identified as Palmer scans, A-scans, and B-scans.

Other applications and other embodiments of illumination chopper arrangements will now become obvious to those skilled in the art from the teachings of this invention and from prior art control arrangements used in conjunction with mechanical chopper arrangements.

The various arrangements described in application Ser. No. 366,714 for controlling illumination permits modulation of illumination for communication of information. The illumination amplifier arrangement shown in FIG. 1 may be used to modulate illumination signals for communication of information. Prior art systems modulate illumination by controlling the source such as with optical couplers using electrical signals for controlling a Light Emitting Diode (LED) source and such as with mechanical modulators used in Navy communication devices to flash digital signals between ships. The illumination amplifier arrangement of the present invention permits modulation of illumination signals for communication of information such as modulating source illumination 102 with amplifier 104 to provide modulated illumination 106; where receiver 112 may include a photocell in an optical coupler arrangement or other receiver or the receiver may be an operator visually monitoring modulated optical signals.

Digital modulation of illumination can be provided with logic arrangements as illustrated in FIG. 2A with gates 210 and flip-flops 200 and 213. In addition, well-known digital arrangements may be used to generate pulse code modulation, pulse width modulation, and other digital modulation arrangements. Signals 214 may be used to control illumination amplifiers to digitally modulate illumination signals. Further, a pulse width modulation arrangement is discussed with reference to FIGS. 2B-2D in application Ser. No. 366,714 to provide pulse width control for illumination amplifier devices. Further, as discussed in application Ser. No. 366,714; an analog amplitude control can be provided for illumination amplifiers that are responsive to analog amplitude signals for controlling illumination in response thereto.

Well-known optical coupler arrangements use a LED source and a photocell sensor to provide electrical isolation. In an improved arrangement, illumination amplifier 104 inbetween source 100 and photosensor 134 controls illumination 102 to be modulated under control of signal 133 to transmit illumination 106 conveying the desired information to photosensor 134.

Because of the solid-state characteristics of many source devices such as LEDs and the batch fabricated solid-state characteristics of illumination amplifier 104 and photosensor 134, a batch fabricated coupling arrangement can be provided. As an example, a monolithic array of source elements 100 may be provided using well-known integrated circuit technology and may be provided in combination with illumination amplifier devices in a batch fabricated configuration to control source illumination 102 with amplifier 104. The monolithic structure associated with solid-state source elements such as LEDs is typically a semi-conductor wafer and may be passivated with well-known techniques such as silicon dioxide. Illumination amplifiers may be constructed using glass substrates such as glass substrates for liquid crystal devices, where the silicon dioxide passivation provides an illumination amplifier substrate for combining source 100 and amplifier 104 structures in monolithic form. Further, well-known monolithic processes for producing photosensors 134 are also compatible with illumination amplifier technology. Therefore, illumination amplifier 104 may be configured in a batch fabricated monolithic form in conjunction with source 100, or photosensor 134, or both source 100 and photosensor 134.

As a further example, LEDs are packaged as individual components with a batch fabricated lens as part of the incapsulation package. Incorporation of illumination amplifiers as part of the lens structure or as part of the monolithic structure associated with source 100 provides a batch fabricated illumination element that is controllable with the very low levels of electric power.

The camera system of the present invention is discussed in detail in application Ser. No. 366,714; particularly with reference to FIGS. 8-10 therein. Additional improvements are discussed hereinafter.

The camera system of the present invention provides a solid-state arrangement for controlling illumination. This is contrasted to prior art arrangements such as the well-known polaroid cameras which use electro-mechanical arrangements such as motors, mechanical shutters, and mechanical apertures for controlling illumination. The solid-state illumination control arrangements of the present invention provide advantages such as low cost, high reliability, low power, extensive flexibility, and others, and further permits batch fabrication.

One embodiment of an aperture arrangement will now be discussed with reference to FIG. 8C. Aperture 820C includes concentric segments 826C, 828C, and 830C. Only three segments will be illustrated for simplicity to exemplify the present invention. In a first embodiment; aperture segments 826C, 828C, and 830C may be controlled to be either transmissive or reflective for three aperture conditions; where segment 830C is controlled to be transmissive and segments 828C and 826C are controlled to be reflective for a first condition, segments 830C and 828C are controlled to be transmissive and segment 826C is controlled to be reflective for a second condition, and all segments 830C, 828C, and 826C are controlled to be transmissive for a third condition. In a second embodiment; aperture segments 830C, 828C, and 826C may all be controlled to be reflective or may all be controlled to be transmissive in various combinations such as segments 826C, 828C, and 830C may have one and only one segment transmissive, may have any pair of segments transmissive, or may have all segments transmissive for seven aperture states. In a third embodiment; segments 826C, 828C, and 830C may be controlled in analog fashion to be partially or totally reflective and/or transmissive to provide a virtually unlimited combination of aperture conditions.

In many applications, it may be preferred to concentrate illumination transmission (or reflection) in a particular portion of the illumination amplifier. For example, a lens introduces greater errors such as distortion at the outer periphery, wherein it is desired to concentrate illumination transmission near the center of the lens. Therefore, in a preferred embodiment of a shutter control in accordance with the present invention, it may be desirable to control shutter 820C to minimize transmissivity of the outer segments. For example, segment 830C may be controlled to become transmissive in analog fashion until it is completely transmissive before the next segment 828C is controlled to be even partially transmissive. When segment 830C becomes fully transmissive, segment 828C will then be controlled to become transmissive, and similarly when segment 828C becomes fully transmissive, segment 826C will then be controlled to become transmissive; thereby maximizing the reflectivity of the outermost segments and relying on control with the innermost segments until they become "saturated" or otherwise limiting.

In one control embodiment, an illumination servo arrangement as described in application Ser. No. 366,714 may be used to control aperture 820C to generate an illumination control signal related to a difference between the desired and the actual illumination transmitted through aperture 820C. A threshold detector would be used to control each of segments 828C and 826C; wherein an error signal below a first threshold would control only segment 830C, an error signal greater than the first threshold but less than a second threshold would be used to control segment 828C with segment 830C being fully transmissive due to the large error signal and an error signal greater than the second threshold would be used to control segment 826C with segments 828C and 830C being fully transmissive due to the large error signal. Such multi-segment control is similar to the use of multi-speed resolver control used in servo systems. In such systems, the one-out-of-three resolvers for control is selected based upon the error signal magnitude and threshold considerations. This well-known multi-speed resolver control concept can be used to provide the multi-segment control for the electro-optical resolver as discussed above.

A method for implementing electro-optical shutter and aperture arrangements will now be discussed for a lens and a liquid crystal device. Aperture and shutter arrangement 820C may be composed of liquid crystal material contained between lens elements having electrodes corresponding to segments 826C, 828C, and 830C provided thereon. Common prior art lens arrangements have combinations of concave and convex surfaces and provide precise mating therebetween. The inter-lens gap or space between lens elements may be filled with liquid crystal material therein and electrodes may be plated on the lens surfaces to provide batch fabricated lens, aperture, and shutter arrangements. One batch fabricated embodiment is illustrated in FIG. 4 of application Ser. No. 366,714. In a preferred embodiment, inter-element gap 436 may have curved surfaces and devices 434, 402, 403, and 435 may be shaped in the form of concave lenses, convex lenses, or various combinations of concave and convex lenses to provide mating therebetween and to provide inter-lens gaps such as gap 436. Gap 436 may be filled with liquid crystal material which may have electrodes thereon to control the transmissivity and reflectivity of the lenses for shutter control, aperture control, filter control, and combinations thereof. The shaping of elements such as elements 434, 402, 403, and 435 into lenses is well known in the optical art such as with lens grinding methods.

Batch fabricated devices 434 and 402 may be lens devices with mating surfaces being concave and convex respectively and having gap 436 filled with liquid crystal material and having electrodes formed on such lens surfaces. In one embodiment, the concave and convex lens may be constructed so that they do not match perfectly but provide a void at interface 436 when placed in contact therebetween. Therefore, gap 436 containing liquid crystal material may be formed as a natural gap by the mating of devices 434 and 402.

A preferred illumination control embodiment uses computer 251 (FIGS. 2C and 9B) for generating command signals 126 to control source 100 with signal 132 generating controlled illumination 102 or to control amplifier 104 with signal 133 generating controlled illumination 106 or combinations thereof. Particular advantages are achieved by controlling amplifier 104 directly from computer 251 when computer 251 is a monolithic data processor as described in detail in the referenced copending applications, particularly in application Ser. No. 101,881. Such a monolithic data processor is low in cost and small in size, but provides output signals that can be used to directly excite illumination amplifiers of large size and having complex arrays of segments; where output signals from such a monolithic data processor implemented with processes such as MOS-FET integrated circuits have sufficient voltage and power levels to directly excite illumination amplifiers. In one embodiment, flip-flops 200 and 213 (FIG. 2A) may be controlled by generating clocks 208 and 215 respectively with discrete output instructions from computer 251 such as described in detail in the referenced applications. As further described in the referenced applications, toggling of flip-flops such as flip-flops 200 and 213 may be performed with a duty cycle related to a desired illumination parameter, thereby providing pulse width modulated signals on lines 204 and 212A to control illumination amplifiers in an analog fashion with signals 214 and 220, as described in application Ser. No 366,714. In an alternate arrangement, pulse width modulated signals and phase related signals may be provided directly from a stored program digital computer such as computer 251 as described in application Ser. No. 366,714 under Analog Excitation and in the other referenced applications.

Discussions which have been cancelled herein entitled Traffic Light Control, Operator Panel, Improved Slide Projector, Integrated Electro-Optic Devices, Improved Fiber Optic Arrangement, Additional Considerations, Optical Effects, Light Organ, and Further Spacial Control Features are provided in parent application Ser. No. 730,756 (which has previously been incorporated by reference herein) at pages 140 to 147, 157 to 164, 166 to 171, and 255 to 262 therein.

Illumination control has been described herein relative to illumination amplifier areas having desired shapes. In one embodiment of illumination control devices in accordance with the present invention, illumination amplifier devices are arranged having an array of miniature segments 1300 (FIG. 13) which will herein be described as micro-segments over an area, where illumination control characteristics of that area may be defined as a sum or an integral of the effects of a multitude of micro-segments controlled individually or as groups of micro-segments. In one embodiment, the micro-segments may be similar to the dot patterns associated with the printing art and known as screened or half-tone arrays of dots. It is well known to those skilled in the printing art that an array of dots in a screened configuration provides an image having the combined effect of a plurality of the dots in a particular area to provide shades of grey or shades of color for the printing process. In a manner analogous to the use of screened printing concepts, an array of micro-segments can be controlled to transmit and reflect illumination; wherein the characteristics of the controlled illumination 108 is related to the combined effects of multitudes of micro-segments in a particular area 1300.

In one embodiment, control of illumination intensity or color or both may be provided with a plurality of sets of micro-segments wherein the illumination amplifier device contains micro-segments from each set interspersed together. For simplicity of discussion, two sets of interspersed micro-segments will be considered. It may further be assumed that a first set of micro-segments 1310 shown shaded covers one-third of the illumination amplifier area 1300 and a second set of micro-segments 1312 shown non-shaded covers the other two-thirds of the illumination amplifier area. When both sets 1310 and 1312 are controlled to be transmissive, all of illumination 102 will be transmitted as illumination 108 and no illumination will be reflected as illumination 110. Similarly, when the first set is excited to be transmissive and the second set is excited to be reflective, one-third of illumination 102 will be transmitted as illumination 108 and two-thirds of illumination 102 will be reflected as illumination 110. When both sets are excited to be reflective, substantially all illumination 102 will be reflected as illumination 110. Therefore, two sets of interspersed micro-segments may be used to provide four states of illumination from full transmissivity to full reflectivity. Further, a larger number of sets of micro-segments can be provided to control the transmitted and reflected illumination, where digital control of sets of micro-segments can provide variations in transmitted and reflected illumination intensity. Therefore, a form of analog control of illumination intensity can be provided by digital control of a plurality of sets of micro-segments. Still further, the micro-segments may have different shapes and different dimensions and sets of micro-segments may be related to different densities such as with different size micro-segments and different quantities of micro-segments, where the embodiment described above can be implemented having the second set of micro-segments providing twice the density either with twice as many of the same size micro-segments or with the same quantities of micro-segments being twice as large as those of the first set or other combinations of size and quantity. Further, micro-segment size and quantity may be determined and may be intermixed in combinations and arrangements to meet the special requirements of the particular application.

From the above discussion, it can be seen that the net effect of an illumination amplifier arrangement may be controlled to provide variations in intensity, in color, or in other characteristics using only digital control of micro-segments. Further, micro-segments can also be controlled with analog excitation to provide additional flexibility for illumination control. Still further, micro-segments can be provided having different color characteristics such as described for color control in application Ser. No. 366,714 to provide color patterns such as is well known in the printing field with color screened type printing techniques.

Yet further, arrays of micro-segments or individual micro-segments can be selected with coincident select excitation to provide the desired illumination control. Such an arrangement may be used for a display such as discussed herein and in application Ser. No. 366,714 for the Operator Panel and the Audience Display System or may be used for arrangements such as for a television receiver. Color television receivers are well known in the art having dot patterns of colored phosphor arranged on a screen and selected with an electron beam scanning the phosphor pattern. A solid state television display may be provided with micro-segments of illumination amplifier devices either individually selectable with a linear select arrangement or, for greater economy, selectable with a multiple dimensional select arrangement such as a two dimensional or coincidence selection arrangement. In such a television display system, arrays of micro-segments may comprise a set of three micro-segments each having a different color such as with phosphorous segments on a color television tube and using the color control concepts described in application Ser. No. 366,714 under Color Control and applied to the micro-segment configuration. Therefore, individual control of each of three colored micro-segments associated with each set of micro-segments may provide the intensity of the three primary colors, thereby yielding the equivalent of a spot having a color related to the combination of the intensities of the three colors of that set of micro-segments as described in application Ser. No. 366,714 under Audience Display System. Still further, sequential selection of each set of three micro-segments will provide the equivalent of the roster scan associated with well-known color television sets.

The above-mentioned display system having sets of micro-segments may be used for black and white television sets, color television sets, and general display systems such as described in application Ser. No. 366,714 under Audience Display System.

The present invention has been described for simplicity using a pair of electrodes providing an electric field therebetween. One feature of this invention provides a plurality of electrodes which may be a quantity greater than two electrodes each having a different control signal for excitation for providing greater control flexibility. For simplicity, this arrangement having a plurality of control signals will be described as summation of electrostatic fields such as with a liquid crystal device. It is herein intended that such an arrangement exemplify more generalized inventive features wherein a plurality of electrodes each have a different control signal and that at least one return electrode be provided as may be required for control of the illumination amplifier from said plurality of electrical control signals.

One embodiment of the miltiple control feature of the present invention will be described with respect to FIG. 8B, where a plurality of electrodes 826, 827, and 830 are provided on one side of the electro-optical material in conjunction with a common electrode on the opposite side of the illumination amplifier material, wherein the electrostatic field between control electrodes 826, 828, and 830 and the common electrode may be defined with well-known electrostatic theory such as described in the textbook Electromagnetic Fields and Waves by Ramo and Whinnery. Any number of control electrodes may be provided wherein the combination of excitation fields, the magnitudes of excitation fields, and other such characteristics define the total excitation field for controlling the illumination amplifier material such as the liquid crystal material. The net effect of a plurality of signals and fields is related to the summation of the excitation signals, the geometry of the electrodes, the geometry of the illumination amplifier structure, and other such considerations that can be analyzed and designed with such well-known electrical field theory.

The plurality of electrodes illustrated in FIG. 8B is merely exemplary of the general features of the present invention, where the electrodes may be shaped, positioned, and oriented therebetween to provide the desired field pattern and where said pluraity of electrodes may be square electrodes within square electrodes as illustrated in FIG. 8B, concentric circular electrodes as illustrated in FIG. 8C, geometric patterns of electrodes as illustrated in FIG. 8A, electrode patterns as illustrated in FIG. 11, micro-segment electrodes interspersed therebetween as described with reference to FIG. 13 and other patterns of electrodes to provide the desired fields for excitation.

In one embodiment, a pair of electrodes may be interspaced so that the field pattern of either electrode can excite the liquid crystal material to be reflective and the absence of excitation from both electrodes will render the liquid crystal material to be transmissive. This arrangement is equivalent to a logical OR gate, where excitation by either one or by both electrodes will control the amplifier to be reflective and where excitation on neither electrode will control the amplifier to be transmissive. In a complement form, a logical AND gate may be provided with complement-excitation (non-excitation) on both electrodes to provide transmissivity, but the absence of complement-excitation (non-excitation) on either electrode will provide reflectivity.

In yet another embodiment, the two control electrodes may have inverse excitation such as positive and negative DC fields or in-phase and out-of-phase AC excitation; where excitation on a first control electrode may provide reflectivity, excitation on neither electrode may provide transmissivity, and excitation on both electrodes may provide a cancellation effect equivalent to the non-excitation state thereby providing transmissivity; thereby providing an A.multidot.B logical operation.

The above-described arrangement may use analog excitation. In one such embodiment, excitation from a plurality of electrodes may be summed either in combinations of inverted and non-inverted forms to provide addition and subtraction with addition and subtraction of fields respectively based upon the related excitation magnitudes. Various types of analog excitations such as analog amplitude excitation, pulse modulated excitation, combinations of analog amplitude and pulse modulated excitation, and other such forms of excitation may be provided for the plurality of control electrodes feature of the present invention.

Control, arithmetic, logical, and other operations may be provided such as with the geometry of the electrodes, the inter-relation of the electrodes, and other such design parameters. For example, a first electrode may be provided for primary excitation and a second electrode may be provided having a geometric relationship with said first electrode to provide fringe fields that are a function of the geometry of the electrode relationships, wherein the effect of the second electrode may provide a non-linear control, mathematical, or digital relationship. Such non-linear relationships may be logarithmic, exponential, geometric, and other desired functions of excitationl

A still further feature of the present invention may provide a greater number of electrodes such as 3 electrodes, 4 electrodes, or 5 electrodes to provide combinations of the operations described above. In one example, digital excitation for a first electrode may provide an enable and disable control operation, bias excitation for a second electrode may provide bias control related to a predetermined level, a third electrode may be excited with a mathematical control function, a fourth electrode may be excited with a non-linear function, and additional electrodes may be used to perform other such functions.

The electric fields and waves art such as described in the textbook Electromagnetic Fields and Waves by Ramo and Whinnery show that the fields outside of the electrode area may provide a fringe field effect. Particular advantage may be achieved with fringe fields when used with liquid crystal devices, exemplary of a general inventive feature having electrodes offset therebetween to provide fringe fields therebetween for excitation of liquid crystal material to exemplify this inventive feature.

A simplified description of the fringe control inventive feature will now be provided with reference to FIG. 11. For simplicity of discussion, it will be assumed that each segment 1142-1145 and 1152-1155 has a corresponding electrode thereunder; co-located, similarly shaped and designated with an A symbol. For example, segment 1144 is assumed to be located directly above and on the other side of the controlled liquid crystal material of a corresponding similarly shaped electrode 1144A. Excitation of electrode 1144 and return electrode 1144A directly thereunder provides a controllable segment shaped as segment 1144. Excitation of segment 1145 and return segment 1145A directly thereunder provides a controllable segment shaped as segment 1145 and further provides a fringe pattern being most intense at the transition between segments 1144 and 1145 and may vary in intensity such as from the center of arrangement 1140 outward to the right therefrom. Similarly, intensity may decrease in relation to the distance from the intersection of segments 1144 and 1145 and may vary as a function of the distance from the center of arrangement 1140. One analysis of the intensity may be made from well-known field theory, where the intensity of the field may control intensity of the reflectivity or transmissivity of the illumination amplifier device.

From the above description, it can be seen that complex patterns of intensities can be provided by excitation and return electrode shapes and positions therebetween. Further excitation of a plurality of electrodes such as electrodes 1142-1145 and 1152-1155 and having corresponding return electrodes 1142A-1145A and 1152A-1155A thereunder can selectively provide complex field arrangements therebetween for providing different geometric patterns and intensities of illumination amplifier action.

The term fringe arrangement is herein intended to mean control of illumination amplifier devices having offset, or non-orthognal, or skewed, or other such relationships and in particular offset electrodes for providing non-perpendicular electrostatic fields therebetween for controlling illumination amplifier devices.

Still further, such offset arrangements may be partially offset, where segments 1144A and 1145A together may define a return electrode and segments 1144 and 1145 together may define an excitation electrode; where segment 1144 thereby defines the common area or superimposed area of return electrode 1144A and 1145A and excitation electrodes 1144 and 1145 and segments 1145 and 1154 thereby define offset portions of the electrodes such as for fringe effects. In one embodiment, common segment 1144 may be larger than segments 1145 and 1154 and therefore segment 1144 may provide the primary illumination control with fringe segments 1145 and 1154 providing only secondary illumination control such as edge or fringe effects, possibly for a soft glow area around the edge of display segments. In still other embodiments, fringe segments 1145 and 1154 may be larger than segment 1144 and therefore segments 1145 and 1154 may provide the primary illumination control.

The arrangements and methods described herein and in application Ser. No. 366,714 are useful individually and in combinations and further may be used in many new and unique applications either individually or in combinations to provide improvements in prior art equipment and methods. Some of these new and unique applications are described hereinafter exemplary of the broad range of applicability of the features of the present invention. It is intended that these specific applications discussed hereinafter be exemplary of the very broad applicability of the features of the present invention.

The system of this invention is discussed relative to photo-electric devices such as the well-known liquid crystal devices. Many of the applications described herein may be described in terms of the "illumination amplifier" concept and embodiment. It is herein intended that the scope of this invention be broadly interpreted and be applicable to a wide range of electro-optical, electro-chemical, and other such devices for controlling illumination that may be used to provide the capabilities described herein which are exemplified with liquid crystal devices.

The instant application (as with the parent application Ser. No. 366,714) incorporates-by-reference copending applications and patents that contribute to the disclosure of the present invention. The pertinence thereof will now be discussed.

The pertinence of application Ser. No. 101,881 will now be discussed.

FIG. 1 of application Ser. No. 101,881 sets forth a data processor 12 for controlling machine 24 with servos 20-22 and discrete control signals 26 and with operator panels 14 and 18. Control of machine 24 with servos and discrete controls is similar to control of the illumination amplifiers of the present invention with servos and discrete control devices. For example, the machine control servos are disclosed using pulse-modulated methods similar to the methods discussed in the instant application. Further, discrete signals can also be used for controlling illumination amplifiers and for providing computer feedback from illumination amplifiers. Still further, the discrete and alpha-numeric displays of display panel 18 can use the illumination amplifier arrangements of the instant application and control panel 14 can use the illuminated switches of the present invention, thereby further describing the usage environment of the illumination amplifier displays.

FIG. 2 of application Ser. No. 101,881 sets forth the detailed operator control and display panel environment for usage and operation of the illumination amplifier devices of the present application. In particular, FIGS. 2C and 2D provide the interface between a monolithic computer and an operator panel which can incorporate the illumination amplifier features of the present invention. Further, this computer interface is exemplary of more general uses discussed in the instant application for control of illumination amplifiers with a digital computer.

FIGS. 3 and 16-19 of application Ser. No. 101,881 exemplifies a servo control with a computer interface, wherein the computer-commanded servo control is usable with the illumination amplifier devices of the present invention in substitution for machine tool 24 of the embodiment discussed in application Ser. No. 101,881.

FIGS. 5-12 of application Ser. No. 101,881 sets forth architecture of one embodiment of a monolithic computer exemplary of the more generalized computer usable with the illumination amplifier features of the instant invention.

FIG. 13 of application Ser. No. 101,881 exemplifies input and output control between a computer and external devices which may be the illumination amplifier devices of the present invention. For example, discrete inputs DI-0 to DI-11 may be used to monitor discrete states such as sensor signals that monitor controlled illumination. Discrete outputs DO-1 to DO-11 may be used to control illumination amplifier devices such as by exciting the illumination amplifier either with a static DC output level set into a flip-flop such as by toggling flip-flops I1 to I4 with discrete outputs DO-8, DO-4, DO-5, and DO-6 respectively; or by directly pulsing the illumination amplifier device such as with a pulse rate modulated signal; or otherwise controlling illumination amplifiers through well-known interface electronics under discrete output control. Whole word outputs OW-O to OW-11 may be used to generate whole number commands such as with packed discretes to the lamps discussed with reference to OW-11 outputs, or to numeric displays discussed with reference to OW-9 outputs, or with analog magnitude information to a digital-to-analog converter which is exemplified with the disclosure set forth in copending application Ser. No. 325,933 discussed hereinafter. Latched discretes and control signals are shown generated with the OW-8 signal loading C-register 260 and generating the C6Q to C15Q signals. Input word signals IW-0 to IW-7 are shown loading feedback information into the computer such as packed discretes from sensors; whole number digital signals from an analog-to-digital converter such as disclosed in aplication Ser. No. 325,933 discussed hereinafter; or other computer input signals.

FIGS. 14A and 14B of application Ser. No. 101,881 further exemplify computer inputs such as loading packed signals T0-T8, P0-P3, M0-M2, J0-J2, and S0-S11 into the computer and also exemplify the output of packed control signals from Z-register 268 with storage flip-flops Z0-Z11.

FIG. 15 of application Ser. No. 101,881 discloses packed output control signals TS-0 to TS-7 and encoded input signals S0-S3 and others.

FIGS. 16-19 of application Ser. No. 101,881 disclose a servo arrangement that is exemplary of servos that may be used for illumination control in place of the machine control.

The pertinence of applications Ser. No. 134,958 and Ser. No. 135,040 will now be discussed. These applications are directed to servo control of a machine with a computer, wherein the machine servo control is also exemplary of an illumination amplifier servo control. This control is disclosed using hardwired servo loops commanded by a computer in an open-loop fashion and also in an alternate embodiment with the computer being in the servo loop. Further, pulse modulated control under computer program control is disclosed wherein the computer may be in the servo loop directly exciting the control device which may be an illumination amplifier and by directly monitoring the feedback device which may be an illumination sensor.

The pertinence of application Ser. No. 288,247 will now be discussed. In particular, application Ser. No. 288,247 is directed to interaction between the operator panel and the computer of the above-discussed application Ser. No. 101,881; wherein the computer flow diagrams of FIGS. 3 and 5-7 of application Ser. No. 288,247 disclose the processing and communication implemented with the hardware diagrams of FIGS. 1, 2, 8, and 9 corresponding to related figures of application Ser. No. 101,881 as discussed above.

The pertinence of application Ser. No. 291,394 will now be discussed. This application is directed to control of a machine by a computer using discrete signals which is exemplary of control of the illumination amplifier arrangements of the present invention with a computer using discrete signals. FIGS. 1, 2, and 4-6 of application Ser. No. 291,394 are similar to related figures of application Ser. No. 101,881 but application Ser. No. 291,394 provides more detailed disclosure relative to discrete control. In application Ser. No. 291,394; FIG. 7 provides a more detailed disclosure of a discrete input and output interface for the computer and FIG. 8 provides program control disclosures relative to controlling of external devices; exemplary of control of illumination amplifier devices with discrete signals.

The pertinence of application Ser. No. 302,771 will now be discussed. This application is also directed to control of a machine with various control methods including servos and adaptive control; exemplary of control of illumination devices in accordance with the present invention. FIGS. 1, 2, and 4A of application Ser. No. 302,771 are similar to related figures in application Ser. No. 101,881 as discussed above. FIGS. 3 and 4B of application Ser. No. 302,771 are exemplary of control arrangements applicable to the illumination control devices of the instant application. FIGS. 6 and 8 of application Ser. No. 302,771 are exemplary of signal processing for control of devices and are directly usable with illumination devices. FIGS. 7 and 10 of application Ser. No. 302,771 are exemplary of computer operations for control of devices such as the illumination devices of the present invention.

The pertinence of application Ser. No. 325,933 will now be discussed. Although this application is directed to audio response, many of the audio control functions are exemplary of illumination control functions. FIGS. 1 and 2 of application Ser. No. 325,933 are similar to related figs. of application Ser. No. 101,881 discussed above and are discussed in greater detail in application Ser. No. 325,933. FIG. 3 of application Ser. No. 325,933 sets forth a detailed analog-to-digital converter, digital-to-analog converter, and computer input/output structure usable in combination with the computer operations of FIG. 6 and are exemplary of generalized converter input/output operations usable with the illumination devices of the present invention. FIG. 5 of application Ser. No. 325,933 is exemplary of generalized computer operations of controlling external devices which may be the illumination devices of the present invention.

The pertinence of application Ser. No. 550,231 will now be discussed. This application is directed to filtering, signal processing, communications, and memory systems which may be implemented with illumination devices disclosed in the instant application. For example, analog and digital illumination computing devices disclosed with reference to FIG. 3 of the instant application may be used to implement the devices of application Ser. No. 550,231 such as disclosed in FIGS. 4, 6, and 7 therein. Further, the illumination devices of the instant application may be usable in combination with or in replacement of the CCD devices of application Ser. No. 550,231 as set forth in FIG. 9 therein.

In view of the above, the disclosures of the referenced copending applications herein incorporated-by-reference exemplify arrangements and methods that are usable with the illumination devices of the present invention and are intended to be usable in combination therewith. For example, the servo control arrangements disclosed in said copending applications are intended to be used in replacement for the servo control arrangements disclosed in the instant application and are in general intended to be usable in combination with the illumination control devices of the instant application. Further, the computer control and interaction disclosed in said copending applications is intended to be usable in combination with the illumination control devices of the present invention where for example the computer 251 disclosed in FIGS. 2 and 9 of the instant application is intended to be supplemented with the computer disclosure of said copending applications.

An illumination amplifier projection display arrangement in accordance with the present invention has been described in parent U.S. Pat. No. 3,986,022 and in application Ser. No. 727,330 wherein the following discussion will more specifically describe preferred embodiments thereof.

Conventional display arrangements typically require an image generator to generate the illumination as a source, wherein the illumination generated by the image generator such as a conventional television (TV) receiver therefore has relatively low intensity. It is well known that projection and magnification of an image reduces intensity of the image. Therefore, it was not practical to project prior art images generated with such image generators. In accordance with the present invention, an image generator is provided that is an illumination amplifier which controls externally generated illumination such as through reflectivity and transmissivity characteristics of the illumination amplifier. Therefore, intensity of the image is a function of intensity of the incident illumination controlled with the illumination amplifier image generator, where very high image intensities may be provided by illuminating the amplifier image generator with high intensity illumination. In accordance with the illumination amplifier feature of the present invention, an image generator may be used in a magnifying projection display system providing high intensity magnified projection displays by illuminating an amplifier image generator with high intensity illumination.

The projection display feature of the present invention will now be discussed in the embodiment of a projection audience display system and particularly in the embodiment of a large screen television display. This preferred embodiment is intended to exemplify but not to limit the general features of the projection display system of the present invention.

A basis for the inventive features discussed hereinafter are set forth in parent U.S. Pat. No. 3,986,022; other related applications discussed therein; and application Ser. No. 727,330. For example, the general features of excitation; batch fabrication; closed loop control; computer control; camera systems; choppers, scanners, and modulators; traffic light controls; and other such implementations discussed in said related patents and applications are directly applicable to the projection display system and are intended to be used in combinations therewith. For example, said U.S. Pat. No. 3,986,022 and application Ser. No. 727,330 discloses a large screen audience display system at pages 104-109, a television display at page 109 lines 28-32, a CRT embodiment at page 84 lines 8-11, a camera embodiment at pages 84-96, color control at pages 61-63 and pages 106-109, multiple source control at pages 99-103, high intensity projection at page 104 lines 28-35, closed loop control at pages 46-49, storage of displayed signals such as with a capacitor at pages 58-60, and batch fabricated arrangements such as at pages 41-45.

Further, application Ser. No. 727,330 includes the above disclosures in addition to the disclosures of television embodiments and scanning embodiments at page 128 lines 21-35, projection of magnified high intensity images at page 128 line 1-12, a slide projector embodiment at pages 146 and 147, fiber optic embodiments at pages 163 and 164, batch fabricated arrangements at page 159 line 30-page 160 line 16 and computer control at pages 139 and 172-177 therein.

It is herein intended that the above-listed disclosures from all copending applications and the other disclosures from said copending applications be considered as usable with the projection display system and are intended for use in combinations therewith, wherein the use of these disclosed implementations and methods may be applied to the projection display system of the present invention in a manner that will become obvious to those skilled in the art from the teachings herein. For example, the projection display system may be batch fabricated, may use fiber optics, may be projected such as with slides or movies, may be projected with high intensity and magnification characteristics, may utilize computerized closed loop control, may use a light pen, may use circuitry discussed for illuminated switch signal storage, may use color control, may be used to expose an illumination sensitive medium, may use multiple sources and multiple colors, and may be used in conjunction with other teachings provided in the instant application and in the referenced copending applications.

A preferred embodiment of the projector arrangement will now be discussed with reference to FIG. 14. Projector 1410 including illumination amplifier 104 generates projected illumination 1414 to a projection screen 1451. Projector 1410 includes image generator 1450 and post-optics 1436. Image generator 1450 generates controlled illumination 1435 and 1437 to post-optics 1436 for post-processing of illumination to generate projection illumination 1414. Post-optics 1436 may be composed of conventional optics arrangements and may include magnifying optics such as provided in conventional projectors including slide projectors and movie projectors. Image generator 1450 may include illumination source 100 which may be any of many well-known sources including light bulbs such as projector bulbs and may be other types of illumination sources such as flame sources used on the well-known searchlights. Source 100 may be controlled with control signal 132 generated with control electronics 127, 128 as discussed in U.S. Pat. No. 3,986,022 with reference to FIG. 1 therein. Illumination from source 100 may be high intensity illumination for projection display and may be concentrated with reflector 1441 which may be a well-known reflector arrangement such as used on flashlights, slide projectors, or searchlights. Source illumination 102 may include direct illumination from source 100 and reflected illumination from reflector 1441. Source illumination 102 may be pre-processed with pre-optics 1433 which may include well-known optical devices such as accumulating and focusing lenses. Pre-processed illumination 1434 from pre-optics 1433 may be controlled with illumination amplifier 104 for generating illumination images. Illumination amplifier 104 may operate in a transmissive mode generating transmissive image 1435 or may operate in a reflective mode generating reflective illumination 1437. Illumination amplifier 104 may operate in response to control signals 133 from control devices 127, 128 as discussed in U.S. Pat. No. 3,986,022 with reference to FIG. 1 therein.

Illumination images 1435 and 1437 may be processed with post-optics 1436 for focusing, magnification, and other well-known optical functions. In a simplified embodiment, projector 1410 may be a well-known slide projector having an illumination source 100, reflector 1441, pre-optics 1433, and post-optics 1436; wherein illumination amplifier 104 may be substituted for the well-known slides in the slide projector.

Illumination amplifier 104 may be a monochromatic arrangement for generating a single-color image 1435 and 1437 or may be a multi-colored arrangement for generating colored images 1435 and 1437; where color arrangements are discussed with reference to FIGS. 6D and 11 of U.S. Pat. No. 3,986,022. In one embodiment, color may be introduced using a colored source 100, colored filters in pre-optics 1433, colored filters in post-optics 1436, or colored segments of illumination amplifier 104. Other methods of introducing color will now become obvious from the teachings herein.

Projection screen 1451 may be any well-known screen. For example, conventional movie and slide projector screens may be used for screen 1451. Alternately, screen 1451 may be a wall of a building which may have a desired coating such as a light colored paint, beaded material, or other such coatings. Alternately, screen 1451 may be a frosted glass screen or other screen material which might be illuminated from one side and viewed from the other side. Screen 1451 may be part of projector 1410 such as with the self-contained screens in TV sets or may be a remote screen such as a slide projection or movie projection screen located remotely from projector 1410. Further, screen 1451 may be a scoreboard, billboard, or other large-scale outdoor-type screen. Yet further, screen 1451 may comprise a plurality of different screens and post-optics 1436 may include prism or beam splitter type optics to project each of a plurality of identical images 1414 on different ones of a plurality of screens 1451 for viewing from different locations such as different sides of a scoreboard.

An alternate embodiment for a color projector will now be discussed with reference to FIG. 14B. Multiple-color projector 1411 comprises three channels of projectors similar to projector 1410 discussed with reference to FIG. 14A. Each of the three image generators 1450 may generate either tramsmitted or reflected illumination images to post-optics 1436 to generate projected image 1414. Each channel, comprising image generator 1450 and post-optics 1436, may represent a different color such as red, green, and blue colors indicated by the R, G, and B symbols associated with the three related channels of illumination. Triple image generators 1452 may generate transmitted illumination 1435, reflected illumination 1437, or combinations thereof. Triple post-optics 1454 may project the three colored illumination beams to screen 1451 so that all three colored beams 1415 are superimposed and have registration therebetween to provide a focused image on screen 1451 that represents the combination of all three colored images 1415.

Another alternate embodiment will now be discussed with reference to FIG. 14C. Triple-image generator 1452 may generate three illumination images which may be transmitted illumination 1435 or reflected illumination 1437 or combinations thereof for processing with combined post-optics 1455. Combined post-optics may combine the three illumination beams such as with accumulating and focusing lenses to generate a single combined colored image beam 1416 for projection onto screen 1451.

Still other alternative embodiments will now be discussed with reference to FIGS. 14D and 14E which represent reflection projection arrangements in contrast to the transmission projection arrangements discussed with reference to FIGS. 14A-14C. In these embodiments, projectors 1410-1412 generate projection illumination 1414-1416 which is reflected from image reflector 1442 to focus on screen 1451. Reflector 1442 may be a magnifying reflector for accumulating, magnifying, focusing, and projecting the image onto screen 1451 as reflected image 1417. A single beam projector 1410 and 1412 (FIG. 14D) generates projected images 1414 and 1416 respectively as discussed with reference to FIGS. 14A and 14C. A triple beam projector 1411 (FIG. 14E) generates triple image beams 1415 in a reflection embodiment as discussed with reference to FIG. 14D above using reflector 1432 to reflect images 1417 to screen 1451.

Projector 1410 may include a zoom capability. The zoom capability which may be implemented electronically or optically. For the electronic implementation, command arrangement 127 and 128 generating control signals 133 may computationally enlarge the image by controlling amplifier 104 to generate a larger optical image under electronic control. Alternately, post-optics 1436 may include a zoom lens capability such as used on slide and movie projectors and other well-known systems to enlarge or reduce image 1414 projected on screen 1451. Zoom capability may be either manual or automatic as implemented in well-known projection systems.

A large-screen-projection television embodiment will now be discussed with reference of FIG. 14. Advances in prior art TV systems and known projection TV systems are discussed in the article New Season's Color TV Sets Slate Major Role For Large-Scale Integration by Gerald M. Walker in the Sept. 30, 1976 issue of Electronics magazine which is incorporated-by-reference herein. This article points out the importance of projection TV systems and the configuration of prior art systems. Such prior art systems use projection tubes, projection lanterns, CRTs, and a trinitron tube, where a major limitation of these prior art arrangements is the low intensity levels available with these projectors. The illumination amplifier feature of the present invention solves the intensity problem and permits a fully solid-state arrangement using low voltage electronics which eliminates vacuum tubes and expensive high-voltage electronics.

In prior art systems, the image generator such as the cathode ray tube (CRT) must generate the image having the desired intensity. The intensity available with CRTs and other such devices is very low and not practically suitable for projection particularly for projection of large images with significant magnification. The image generator of the present invention does not generate its own illumination but controls externally generated raw illumination as an illumination amplifier. For example, illumination amplifier 104 is not a source of illumination but merely modulates or amplifies illumination from source 100, wherein low level electrical signals 133 may be used to control high intensity images 1435 for projection with post-optics 1436. It is estimated that intensity of image 1435 using illumination amplifier 104 may be hundreds or thousands of times more intense than the intensity of images generated with conventional techniques such as CRTs. For example, conventional televisions using CRTs are marginally acceptable, where the CRT is adequate for a darkened room and a non-projection system. If a 24-inch CRT TV picture were projected to a four-by-six-foot large screen, the intensity of the projected image would be approximately one-sixth of the intensity from the CRT in a non-projection configuration. Obviously, this one-sixth of normal TV intensity would be inadequate. Therefore, exotic techniques, higher voltage circuitry, and other expensive methods are used to increase image intensity using conventional techniques.

In the system of the present invention, a small illumination amplifier device 104 may be used in conjunction with a high intensity source 100 to generate high intensity large-screen projection images 1414. Present photo-lithographic integrated circuit techniques make it relatively simple to provide small 0.001-inch elements on a substrate. Therefore, the 512-by-512-point resolution of a TV CRT may be implemented on an illumination amplifier device such as a liquid crystal device of approximately one inch square. Illumination of a small image such as a one-inch-square image formed on illumination amplifier 104 using high intensity raw illumination 1434 will permit projection and magnification of the small image to large dimensions with post-optics 1436 for projection onto screen 1451.

In a TV embodiment, conventional TV signals may be received and processed with conventional TV electronics. Video signals may be electronically scanned across illumination amplifier 104 with well-known electronic scanning methods such as the TV raster scan. Each amplifier element may have a memory element related thereto such as a flip-flop or capacitor as discussed with reference to FIG. 6C in U.S. Pat. No. 3,986,022. Accessing of an array of elements such as liquid crystal elements is well known in the art such as two-dimensional coincident excitation arrangements used with core memory systems.

The projector arrangement discussed above will now be discussed with reference to FIG. 14F to illustrate use in a complete TV receiver system. TV signal 1459 may be received with TV receiver 1460 comprising well-known antennas and tuner, RF, video, IF, and audio circuitry to generate video signals 1461 to TV signal processor 1462. Signal processor 1462 may include well-known TV signal processing circuitry such as used with well-known solid-state image generators. Control 127 and 128 generates control signal 133 in response to processed signal 1463; wherein signal 133 may include scan control and intensity control signals and may further include pulse width modulated or other signal characteristics such as discussed in said U.S. Pat. No. 3,986,022. Control signal 133 controls illumination amplifier 104 to control illumination 1434 to generate controlled illumination 1435, 1437 which is projected with post-optics 1436 as projected signal 1414 to illuminate screen 1451; as discussed with reference to FIG. 14 herein.

In view of the above, it can be seen that the arrangement disclosed in FIGS. 14A-14E can be implemented in combination with well-known TV front-end circuitry to provide an implementation of a complete TV receiver.

The arrangement discussed with reference to FIG. 14 may be implemented in the form of a conventional projector arrangement such as a TV receiver or in the form of a holographic projector. In the conventional projector arrangement, source 100 may be a non-coherent illumination source such as a zenon lamp, mercury vapor lamp, incandescent lamp, or other well-known lamps which may be of a high intensity variety and illumination amplifier 104 may provide conventional images such as viewed on a conventional TV display. Alternately, this projection system may be implemented with a coherent illumination source 100 such as a laser or other coherent source and illumination amplifier 104 may display holographic patterns such as interference patterns for generating and projecting holographic images as images 1435, 1437, and 1414. In a conventional projection arrangement, a projected illumination image may be projected upon a screen to provide a two-dimensional image. In the holographic embodiment, illumination images 1435, 1437, and 1414 may be holographic images and may be projected on a screen such as screen 1451 or may be projected without a screen for providing three-dimensional holographic images.

In accordance with the holographic projector arrangement discussed above, a holographic TV camera can be provided, wherein holographic images may be provided with the appropriate optics such as lenses and a conventional television camera may be used to take moving video pictures of the holographic interference patterns for transmission to the receiver, discussed with reference to FIG. 14F, to provide a three-dimensional holographic TV system.

Because of the integrating effect of the human eye, photographic film, etc. and because each illumination image portion is independently formed in a non-coherent system, a scanned image such as with the raster scan in a conventional TV system is acceptable. In a holographic system, dependence is placed on interference between phases of different image portions. Therefore, it may be desirable to provide projection of a complete holographic image rather than projection of a scanned image.

In one embodiment, a holographic image may be scanned onto illumination amplifier 104 with control signal 133; may be temporarily stored on amplifier 104 such as with capacitors; and coherent source 100 may be de-energized during scanning. After the holographic image has been fully stored on amplifier 104, source 100 may be energized to project stored image 1435, 1437 as illumination 1414. In a multiple-channel system such as discussed with reference to FIG. 14B, the multiple channels may be scanned in an interleaved manner and may be sequentially projected. For example, while a red image is being scanned in the red channel R and therefore non-projecting, the green channel G and blue channel B may be projecting green G and blue B images 1415. Such interleaved operation may be implemented in the form of a well-known refresh arrangement and image information to be scanned may be stored in memory 1464 performing a buffer or refresh function.

Because of said integration effect, the pulsed operation of the holographic system is analogous to the scanned operation of a conventional TV system. Pulsing of lasers and control thereof is well known in the art.

The projection feature of the present invention may be used in a recording embodiment, where screen 1451 may be an illumination sensitive medium 130 such as film, light sensitive paper, a phosphor surface, or other well-known illumination sensitive mediums, where exposure of medium 130 is discussed in U.S. Pat. No. 3,986,022. Projection of an image onto medium 130 used in place of screen 1451 can provide a permanent record of information displayed with amplifier 104. In this recorder embodiment, amplifier 104 may be a physically small element such as one-square-inch television image or may be a physically large element such as a ten-square-inch arrangement for greater resolution. Post-optics 1436 may magnify or reduce image 1435, 1437. Magnification of a small image may be provided for using a smaller, lower resolution amplifier 104 in conjunction with a recorded image to be used by an operator such as on an 81/2-by-11-inch page. Alternately, the system may be used for microfilm reproduction wherein a high resolution image 1414 is required and wherein image 1414 is very small for printing on microfilm. For this embodiment, illumination amplifier 104 may be large for providing greater image resolution and post-optics 1436 may provide illumination image reduction capability to print or record a high resolution miniature image 1414 on microfilm.

In another embodiment, post-optics 1436 may include a scanner for scanning image 1435 onto screen or medium 1451. The scanner may be a well-known prior art electro-mechanical scanner such as used in Xerox copiers and OCR systems or may be the electro-optical scanner discussed in application Ser. No. 727,330 with reference to FIG. 12 therein and as further discussed herein. In this embodiment, the scanner may scan an image such as a rectangular image across screen or medium 1451 as discussed for the photoplotter with reference to FIGS. 8 and 10 in U.S. Pat. No. 3,986,022. Alternately, image 1435, 1437 from amplifier 104 may be continuously changing as it is scanned across screen 1451 or medium 130. For example, control signal 133 may control a sequence of alpha-numeric characters which are scanned across a screen or medium 1451 for displaying or recording alpha-numeric information, wherein each scanned position may correspond to a different character commanded by signal 133, as discussed with reference to FIG. 12B of application Ser. No. 727,330.

The TV system of the present invention includes many additional advantages implicit in the small size, simplicity, and projection aspects. For example, this TV set may be used in a manner similar to common slide projectors and movie projectors wherein post-optics 1436 may include zoom capability, screen 1451 may be a portable screen or a wall and projector 1410-1412 may be a portable TV projector for projecting colored TV pictures on various types of screens and walls. Post-optics 1436 may also include well-known focusing optics as is common in slide projectors for focusing image 1414 on screen 1451 to provide projection from different distances and positions.

A high-intensity low-power portable embodiment of the TV system of the present invention may be provided, wherein source 100 constitutes the high-power dissipation element of the system and may be implemented as a flame-type lamp and wherein power-consuming electronics in projector 1410 may be powered with batteries. Lamp 100 may be a gas lamp or other lamp such as used on searchlights, lanterns, and in lighthouses to provide high-intensity illumination without electrical power consumption. Integrated circuit electronics may be used to drive illumination amplifier 104, where typical illumination amplifiers such as liquid crystals have very low power dissipation and wherein integrated circuit electronics do not need high voltage and high powered drives usually required for conventional television sets and therefore may be provided in a low-power battery-operated portable configuration.

Flexibility of the instant projection TV arrangement permits operation with many different screens including a self-contained screen for close viewing and a remote projection screen for audience-type viewing. Illumination intensity may be controlled such as a function of the viewing screen using pulse or amplitude modulation as signal 132 to source 100 or signal 133 to illumination amplifier 104. Portable screens may be used such as a removable self-contained screen for self-contained viewing and a remote screen such as a folding slide projector screen for audience viewing. Use of both, a removable self-contained screen and a portable remote screen, in conjunction with zoom and focusing capability in post-optics 1436 permits adaptation to many different viewing situations.

In another embodiment, illumination amplifier 104 may be coupled to provide illumination to an illumination sensitive medium such as photographic film or a phosphorus screen using fiber optic techniques such as used on the Honeywell VISICORDER. Use of an illumination diffuser as a projection screen at the remote end of a fiber optic bundle permits high intensity illumination from a small image to enter the source end of a fiber optic bundle, where divergence of the fiber optic strands permits a larger image to be projected or conducted from the destination end of the fiber optic strands to a larger screen (or alternately a smaller screen) for display purposes.

The pictorial image feature of the present invention exemplified with a TV projection system may also be used for hardcopy recording of pictorial information. For example, use of an illumination sensitive medium 130 included in screen 1451 permits recording of pictorial information such as in a facsimile machine, a pictorial copier, or other such systems.

In the multi-beam embodiment, one beam may be used for operator viewing of a projected image and another beam may be used for recording of that image. For example, in a TV system used for projection viewing, it may be desired to record an image. Therefore, an illumination amplifier shutter may be used to expose an illumination sensitive medium with an alternate beam or with a redirected primary beam such as discussed for the single-lens reflex camera with reference to FIG. 9 of U.S. Pat. No. 3,986,022. Said reflex camera provides viewing to set up the picture and recording to expose the illumination sensitive medium using a single directionally controlled image beam. Alternately, a plurality of beams may be provided for simultaneous viewing and recording. Therefore, in accordance with this feature of the present invention, a system is provided for viewing an image and for recording an image using illumination amplifier devices such as a liquid crystal arrangement.

A plurality of controllable segments have been described relative to photoplotter and camera-type systems with reference to FIGS. 8A-8C and for a character display system such as with reference to FIG. 6 of U.S. Pat. No. 3,986,022 and further with reference to FIG. 12B of application Ser. No. 727,330. In an alternate embodiment, these segment illumination control arrangements may be implemented with the image control arrangement discussed for the image projection system such as for TV receivers. For example, the resolution of the TV image control system provides rectangular images at a very large number of angles relative to the 45-degree angular increments discussed with reference to FIG. 8A of U.S. Pat. No. 3,986,022 and may provide a very large number of different types of characters for a character generator in addition to a common set of alpha-numeric characters. Further, aperture control such as discussed with reference to FIGS. 8B and 8C of U.S. Pat. No. 3,986,022 may be provided with significantly greater resolution by using a large number of illumination amplifier segments compared to the three segments shown in said FIGS. 8B and 8C.

An alternate scanner embodiment will now be discussed with reference to FIG. 12E. Illumination control device 1279 includes a plurality of controlled surfaces 1270-1276 for controlling illumination signals 1250-1256 respectively as controlled reflected signals 1260-1266 respectively. Controlling of elements 1270-1276 to be selectively reflective causes illumination from source 110 to be selectively scanned with signals 1260-1266 such as onto screen 1223. For example, generator 1224 may generate illumination characters in response to illumination 102 from source 100, 1225 which may be selectively reflected from surfaces 1260-1266 to scan the illumination characters onto screen 1223, as discussed with reference to FIG. 12E in copending application Ser. No. 727,330. For example, characters generated with generator 1224 along incident beam 1250 may be reflected as signal 1260 if element 1270 is reflective and may not be reflected as signal 1260 if element 1270 is not reflective. Similarly, incident illumination signals 1251-1256 may be reflected or nonreflected from elements 1271-1276 respectively as signals 1261-1266 respectively depending upon whether elements 1271-1276 are controlled to be reflective or nonreflective. Signals B0-B6 may be used to control elements 1270-1276 similar to the arrangement discussed with reference to FIGS. 12A-12D in application Ser. No. 727,330 and other approaches may be used to control devices 1270-1276 similar to that discussed for the other scanner embodiments.

The arrangement discussed with reference to FIG. 12E is shown in simplified form for ease of description. Elements 1270-1276 may be a batch fabricated device such as discussed with reference to FIG. 4 in U.S. Pat. No. 3,986,022 and may be formed as facets 1270-1276 or flat areas on spherical substrate 1279 which may be a glass substrate. Alternately, continuous control may be provided over the surface of a single continuous circular or spherical surface providing different reflecting angles using analog spacial methods of moving a reflecting area over substrate 1279 similar to well-known prior art analog spacial arrangements. Alternately, elements 1270-1276 may be individual elements that are not batch fabricated which may be implemented with well-known methods such as liquid crystal methods wherein each device 1270-1276 may have an innermost electrode closest to the center of hemisphere 1279 being reflective and being covered with liquid crystal material and may have an outermost transparent electrode for containing the liquid crystal material between the inner reflective electrode and substrate and the outer transmissive electrode and cover as is well known in the reflective liquid crystal art for providing reflective mode operation. When the liquid crystal material is controlled to be opaque or scattering, illumination 1250-1256 may not be able to penetrate the reflecting electrodes and therefore may not be reflected but may be scattered. When the liquid crystal material of a device 1270-1276 is controlled to be transmissive, incident illumination 1250-1256 respectively will be transmitted by the outermost transparent electrode, transmitted by the transparent liquid crystal material, and reflected by the reflective innermost electrode back through the transparent liquid crystal material and through the transparent outermost electrode as reflected signals 1260-1266 respectively. Therefore, the arrangement discussed with reference to FIG. 12E can be controlled to provide all of the capabilities discussed with reference to FIGS. 12A and 12B in said copending application Ser. No. 727,330.

Further, substrate 1279 may be spherical in shape with reflective facets like the well-known devices used for a reflective effect such as in ballrooms, but with the difference that the faceted mirrors have controllable reflectivity such as for controlled scanners, choppers, and other illumination control arrangements.

The arrangement shown in FIG. 12E is intended to be indicative of a solid-state version of a scanning mirror such as provided in Xerox machines and other scanning devices. In such devices, as the scanning mirror is rotated from an angle shown with element 1270 to an angle shown by element 1276 through angles shown by elements 1271-1275; illumination is reflected through the angles shown by illumination beams 1260-1266 respectively. Therefore, the arrangement shown in FIG. 12E provides a solid-state electro-optical device for replacing prior art opto-mechanical scanning arrangements.

A scanner embodiment is described in referenced application Ser. No. 727,330 with reference to FIG. 12B and FIG. 12C therein and with reference to FIG. 12E herein; wherein source 1225 illuminates generator 1224 to provide an image to be scanned onto a screen with scanner segments 1230-1237 or 1260-1266 respectively. In an improved embodiment, segments 1230-1237 or 1260-1266 may be formed having alpha-numeric or other characters wherein the characters may be generated at surfaces 1230-1237 or 1260-1266 rather than with a separate generator 1224. If each of surfaces 1230-1237 or 1260-1266 contained image generation capability such as controllable segments for alpha-numeric characters as is well known in the art, then control of the appropriate surface to have selected segments reflective and for all other surfaces to be transmissive would project the appropriate segments and therefore the desired characters onto screen 1223. In this embodiment, the corresponding segment on each of surfaces 1230-1237 or 1260-1266 may be connected together in parallel for selecting that corresponding segment on all surfaces. Selection of the particular surface would be provided by selecting the appropriate one of eight return electrode signals B0-B7 (FIG. 12C) so that only the selected surface would have the segments reflective for display of the controlled character on screen 1223.

This arrangement is analogous to well-known display refresh electronics, where a particular character out of a plurality of characters is selected with individual character select signals and where all of the corresponding segments of the plurality of characters are connected in parallel to a particular segment control signal. Therefore, coincidence of a character select signal and the segment select signals define which segments of which character are to be displayed. Such an arrangement is discussed in detail in related application Ser. No. 101,881 relative to FIG. 2D and in related application Ser. No. 288,247 relative to FIG. 4 therein showing character select control signals and segment select controls from select drivers and from segment drivers respectively for a segment display tube wherein said FIG. 2D and FIG. 4 and the related discussion are herein incorporated-by-reference. A similar selection embodiment using liquid crystal type characters on angular surfaces shown in said FIG. 12B and FIG. 12E can be used to implement the scanning of multiple characters onto a refreshable screen 1223.

In another embodiment, generator 1224 may be constructed as an integral part of scanner 1222; such as with another layer above surface 1230 (FIG. 12C) wherein the projection image may be formed with integral generator 1224 and may be reflected to the correct position on screen 1223 having a batch fabricated self-contained character generator and scanner arrangement.

In accordance with the projection display arrangement of the present invention, display arrangements 1220 and 1201 may be miniature displays and screen 1223 may be a large screen, wherein post-optics 1436 (FIG. 14) may be used to project and focus scanned images 1240-1247 or 1260-1266 along screen 1223 (FIG. 12B and FIG. 12E) and onto screen 1451 (FIG. 14A).

A further important feature of the scanner and projector arrangements of the present invention includes the ability to scan high intensity illumination that is magnified to large dimensions such as with pre-optics 1433 or post-optics 1436 (FIG. 14A). For example, pre-optics 1433 (FIG. 14A) may be inserted between source-generator 1224 and electro-optical device 1222 and 1279 for focusing projected characters formed with generator 1225 onto small controllable reflectors 1230-1237 and 1270-1276 respectively for selectively scanning or controlling projection of illumination from source 1225 and generator 1224. Focusing of illumination onto devices 1230-1237 and 1270-1276 forms a very small beam of illumination focused on devices 1230-1237 and 1270-1276 and reflected from devices 1230-1237 and 1270-1276 to project large magnified images on a screen with a very small focused beam using very small-sized reflecting devices.

Spacial control of illumination is well known in the art using resistive electrodes for providing potential gradients. Another feature of the present invention provides such spacial control of illumination using thickness of electro-optical material. For simplicity, this arrangement will be discussed for liquid crystal material with reference to FIG. 15A and FIG. 15B.

Liquid crystal material 1512 may be sandwiched between a pair of glass substrates 1510 and 1511 having electrodes 1513 and 1514 respectively deposited or otherwise placed thereon. A retainer 1515 for liquid crystal material 1512 may be constructed with teflon and a sealer 1519 may be constructed with epoxy. The arrangement shown in FIG. 15A represents a cross section, wherein retainer 1515 and seal 1519 encapsulate liquid crystal material 1512 in the vertical plane and substrates 1510 and 1511 encapsulate liquid crystal material 1512 in the vertical plane and substrates 1510 and 1511 encapsulate liquid crystal material 1512 in the horizontal plane. In FIG. 15A, liquid crystal material 1512 is shown deeper at the left-hand side and shallower at the right-hand side and is shown in FIG. 15B deeper in the center and shallower at the outer periphery implemented by properly dimensioned retainer 1515 and seal 1519 and may be further implemented with substrates 1510 and 1511 ground at sloping angles down to the left as shown in FIG. 15A and down toward the outer periphery as shown in FIG. 15B. Excitation of liquid crystal material 1512 with the proper constant voltage across electrodes 1513 and 1514 will cause the liquid crystal material at the shallower right-hand portion of FIG. 15A and at the shallower outer periphery of FIG. 15B to become opaque and will preserve the transmissive nature of the liquid crystal material 1512 at the deeper left-hand side of FIG. 15A and deeper central portion of FIG. 15B. As the electrical field between electrodes 1513 and 1514 is increased the liquid crystal opaque region interface at the shallower right-hand portion shown in FIG. 15A will move towards the left and the liquid crystal opaque region interface at the shallower outer periphery shown in FIG. 15B will move towards the center thereby encompassing a greater area. Conversely as the electric field is decreased, the liquid crystal opaque region interface at the shallower right-hand portion shown in FIG. 15A will move towards the right and the liquid crystal opaque region interface at the shallower outer periphery shown in FIG. 15B will move towards the outer periphery thereby encompassing a lesser area. This variable depth method may be used in combination with the well-known prior art method using resistive electrodes to obtain an additional degree of freedom of control.

Spacial control is well known in the prior art such as controlling the relative transmissive and opaque areas of the liquid crystal device. These arrangements are inaccurate because of the difficulty in controlling liquid crystal device thresholds, excitation voltages, and other characteristics. A feedback arrangement will now be discussed to provide precise spacial control such as to control the relative areas that are opaque and transmissive of a liquid crystal device. Use of the closed loop feedback method of the present invention significantly enhances precision of spacial control, as will now be discussed with reference to FIGS. 1 and 15A. The electro-optical arrangement shown in FIG. 15A may be illumination amplifier 104 shown in FIG. 1. Illumination 102 from source 100 may illuminate amplifier 104 controlled with signal 133 to generate controlled illumination 108 and 110. Feedback sensor 134 generates feedback signal 114 in response to illumination 110, wherein signal 114 is processed with signal processor 116 and command device 127 and signal processor 128 for control of amplifier 104. Control may be analog control or digital control and may be pulse modulated control or other forms of control discussed in U.S. Pat. No. 3,986,022 wherein digital excitation is discussed with reference to FIG. 2A, pulse modulated excitation is discussed with reference to FIGS. 2B-2D and other forms of excitation are discussed elsewhere therein.

One embodiment of a feedback arrangement will now be discussed with reference to FIG. 15A as a multiple-loop spacial feedback control arrangement, where this arrangement may also be used with other embodiments such as discussed in U.S. Pat. No. 3,986,022 and application Ser. No. 727,330 and elsewhere herein.

Source 100 illuminates amplifier 104 with source illumination 102 to generate controlled illumination 110 comprising signals 110A, 110B, and 110C. Illumination 110 exposes sensors 134 comprising AGC control sensor 134A and spacial control sensor 134B to generate feedback signals 114 comprising AGC feedback signal 114A and spacial control feedback signal 114B to be compared with command signals 126 comprising a scale factor or AGC command signal 126A and a spacial command signal 126B to feedback signal processors 116, 128 to generate control signal 132 and illumination amplifier control signal 133. This arrangement is exemplary of a multiple-feedback arrangement such as for AGC and spacial control and is also exemplary of other multiple feedback arrangements usable with other embodiments discussed herein; in U.S. Pat. No. 3,986,022; and in application Ser. No. 727,330. Source 100 may generate illumination 102 in response to feedback signal 114 where source control is exemplary of automatic gain control and wherein other arrangements may be used such as control of an electro-optical device 104 to control source illumination. Illumination 102 is controlled by illumination amplifier 104 such as having liquid crystal material 1512 in a spacial control. The transmissive region of the spacially controlled material is shown in the right-hand portion of FIG. 15A wherein the thicker the liquid crystal material the more likely it is to be transmissive and wherein the thickest spacial region is the last region to become opaque, as discussed above. Therefore, sensor 134A providing a form of automatic gain control (AGC) may be placed in a region that is the least likely region to become non-transmissive or alternately may be placed to directly sense source illumination 102 for AGC. AGC illumination 110A may be sensed with sensor 134A to generate feedback signal 114A which may be compared with command signal 126A using processor 116, 128 to generate control signal 132 to control source 100.

Similarly, spacial illumination control may be provided with feedback arrangement 1502 where source illumination 102 as controlled by illumination amplifier 104 may be received as controlled illumination 110B, processed with post-optics 1436 to generate post-processed illumination 110C for illuminating sensor 134B. Sensor signal 114B may be processed with processor 116, 128 to generate illumination amplifier control signal 133 for controlling illumination amplifier 104. Post-optics 1436 may include an accumulating lens for accumulating a portion of or all of the illumination from illumination amplifier 104 to provide spacial control of amplifier 104.

Processor 116, 128 may compare feedback signal 114B with command signal 126B to generate a difference signal 133 to provide spacial control to make a particular area proportional to command signal 126B opaque or transmissive. For example, if command signal 126B is at one-quarter of the peak amplitude; processor 116, 128 may generate command signal 133 to servo the amplifier 104 to make three-quarters of the area opaque and one-quarter of the area transmissive to generate feedback signal 114B being one-quarter amplitude. When command signal 126B and feedback signal 114B are each related to one-quarter illumination amplifier magnitude, the difference signal 133 will maintain illumination amplifier 104 having that particular excitation level and that spacial illumination control level. Therefore, the amplitude on command signal 126B defines the relative areas of amplifier 104 that are opaque and transmissive.

Spacial control used to form lines, circles, segments, and other constant area devices are well known in the art by providing positive and negative excitation to resistive electrodes wherein the transition through zero voltage gradient provides the desired line or other shaped element. Biasing of the constant gradient is used to control the position of the transmissive element. The prior art does not control dimensions nor characteristics of the transmissive or opaque element except as fixed in the design of the device. An arrangement will now be discussed, to control the characteristics of the element in addition to the prior art methods of providing spacial control.

Biasing of the constant slope gradient is used in the prior art to provide spacial control. In accordance with the present feature of the present invention, the slope of the gradient may be controlled to control the spacial distance covered by the line or other element, to control the sharpness and other characteristics of the edges, and to provide other such capabilities. Such gradient slope control may be provided with an illumination feedback loop in the form discussed with reference to FIG. 15A herein. For example, control of an element such as a line or circular arc may be provided with feedback loop comprising post-optics 1436 to accumulate the illumination as illumination signal 110C, sensor 134B for generating feedback signal 114B proportional to illumination signal 110C, processor 116, 128 for processing feedback signal 114B and for comparing feedback signal 114B with command signal 126B to generate illumination amplifier control signal 133 to control illumination amplifier 104. Command signal 126B may define the amount of illumination to be transmitted by amplifier 104 and may be used to change the gradient of the electrode voltage on amplifier 104 such as by increasing the positive excitation and decreasing the negative excitation such as with push-pull or inverter amplifier techniques. This gradient slope control may change the shape of the transmissive element and the edgequity or sharpness of the edges.

Further, a plurality of feedback loops may be provided such as for shape control of the illumination element, spacial position control of the illumination element, and control of other such characteristics. Further, the system may operate in a reflective mode wherein the more remote electrode 1514 may be reflective for reflecting illumination 102 in contrast to the transmission of illumination 102 shown in FIG. 15A and wherein sensors 134 may sense reflected illumination.

One embodiment of the spacial control feature of the present invention is a spacial controlled clock such as a watch 1520 (FIG. 15C). Liquid crystal watches are well known in the art such as providing digital displays 1521. The liquid crystal watch of the present invention uses area control to provide analog rotational motion similar to mechanical watches with second, minute, and hour hands. Because the angular position of a display element may be controlled with spacial control gradient methods, these elements may be used to provide pointers on a watch. For example, controlled illumination area 1522 may represent an hour pointer which may traverse the periphery of watch 1520 once every 12 hours and illumination pointer 1524 may be a minute pointer and may traverse the periphery of watch 1520 once every hour and further other pointers may provide second information and date information accordingly. The position of these pointers 1522 and 1524 may be controlled with digital electronics used to generate digital displays 1521 which are well known in the art. These digital electronics may excite digital-to-analog converters 1227 to control the gradient by exciting resistive electrodes to control the position of pointer elements 1522 and 1524. The analog spacial control pointers of watch 1520 may be used in conjunction with digital display 1521 or in replacement thereof.

An alternate embodiment is shown in FIG. 15B where a circular symmetry spacial control arrangement is provided. Illumination amplifier 104 is shown in section circular symetry form having feedback servo 1502 generating feedback control signal 133 in response to controlled illumination 110B similar to that discussed with reference to FIG. 15A. Feedback servo 1502 may have post-optics 1436 for generating a post-processed illumination signal 110C to illuminate sensor 134B for generating feedback signal 114B to be compared with command signal 126B. Processor 116, 128 may compare feedback signal 114B with command signal 126B to generate feedback control signal 133 to control illumination amplifier 104. Illumination amlplifier 104 may comprise glass substrates 1510 and 1511, electrodes 1513 and 1514 on substrates 1510 and 1511 respectively, spacer and support 1515, sealer 1519, and liquid crystal material 1512.

Substrates 1510 and 1511 may be formed to provide thicker liquid crystal material at the center and shallower liquid crystal material at the outer periphery as shown in FIG. 15B. Therefore, excitation 133 controls the liquid crystal material at the outer periphery to become opaque before the center liquid crystal material becomes opaque. As excitation is applied and increased in magnitude, liquid crystal material at the outer periphery near spacer 1515 becomes opaque but the liquid crystal material towards the center remains transparent. As the excitation is increased, the outer periphery of opaque material increases in area radially inward towards the center until a level of excitation is reached sufficient to make the deeper liquid crystal material at the center opaque. Therefore, the arrangement shown in FIG. 15C may be used to electronically control the radius of the central transparent area 1505.

Alternately, substrates 1510 and 1511 and spacer 1515 may be formed to provide thicker liquid crystal material at the outer periphery and shallower liquid crystal material at the center to provide a transparent circle at the outer periphery that increases in radius away from the center as excitation is increased, providing the complement of operation of the arrangement shown in FIG. 14B. Further, the arrangement shown in FIG. 15B may use the high resistance electrode arrangement or other techniques to provide electric field gradients to generate a transparent (or opaque) spot 1505 and to control the radius of spot 1505 for illumination control.

The arrangement discussed with reference to FIG. 15B may be used as a camera shutter and aperture such as discussed with reference to FIGS. 8-10 in U.S. Pat. No. 3,986,022 and application Ser. No. 727,330. A command signal 126B may be input to feedback servo 1502 (FIG. 15B) to generate control signal 133.

If command signal 126B is a large command signal, servo 1502 generates a large excitation signal 133 which causes the complete area of liquid crystal material 1512 to become opaque and spot 1505 to reduce to zero radius of transparent material; thereby blocking all of illumination 102 and implementing a shutter. This shutter may be used in conjunction with mechanical shutters and other photographic camera devices as discussed with reference to FIGS. 8-10 of U.S. Pat. No. 3,986,022. Changing of control signal 126B to a command magnitude less than the threshold magnitude for the thicker center liquid crystal material causes transparent spot 1505 to form having a radius that is a function of the magnitude of command signal 126B.

Control of transparent spot 1505 is similar to control of an aperture such as a prior art mechanical aperture for controlling the amount of illumination transmitted. Therefore, a camera using the arrangement shown in FIG. 15B controls exposure of an illumination sensitive medium 130 by initially maintaining shutter aperture arrangement 104 opaque with a high magnitude command signal 126B and then generating said lower magnitude threshold signal 126B in response to an exposure command signal to provide a transparent spot 1505 having a desired radius that is a function of an aperture or illumination magnitude camera setting. After a particular exposure time, signal 126B is returned to the high magnitude value to again control illumination amplifier 104 to be fully opaque to terminate the exposure. The shutter magnitude may be a characteristic of the camera system such as a fixed high magnitude level and the exposure magnitude may be settable such as with a well-known potentiometer setting to control the aperture to define the threshold magnitude of signal 126B to control the radius of transparent spot 1505 with feedback signal 133 for the duration of the exposure. Well-known prior art timing arrangements may provide timing for the exposure in response to an exposure command from an operator, switching to the lower magnitude exposure signal in response to the exposure command and then switching command signal 126B back to the higher magnitude shutter signal after the time delay for exposure has expired.

The arrangement discussed with reference to FIG. 15B may operate as a conventional aperture in an open loop command arrangement or may operate as an adaptive aperture for the closed loop control arrangement shown in FIG. 15B. For example, generation of control signal 133 in response to command signal 126B causes a controlled diameter of transparent spot 1505. Use of feedback servo 1502 operating in response to illumination 110B causes the diameter of transparent spot 1505 to be controlled to a magnitude that is a function of the command signal 126B and the magnitude of incident illumination 102. Therefore, the greater the command signal 126B the larger will be the diameter of transparent spot 1505 and the greater the magnitude of incident illumination 102 the smaller will be the diameter of transparent spot 1505 implicit in the operation of servo 1502.

A camera control system will now be discussed with reference to FIG. 15D. For simplicity of illustration, a Texas Instruments 74122 time delay multivibrator and a Fairchild 709 operational amlplifier will be used to exemplify this invention, although many other control arrangements may be provided. Multivibrator 1530 generates output pulses Q and Q in response to closure of switch 1531 to excite input A1, where switch 1531 initiates an exposure. The width of output pulse Q is determined by the values of capacitor CE and resistor RT to multivibrator terminals C and R/C. Resistor RT may be a variable resistor for controlling time duration of output pulse Q, where resistor RT controls exposure time. The exposure may be interlocked with many different signals using inputs B1 and B2 and using other signals ANDed or ORed together using well-known logical techniques. For example, a switch may be closed by the film being wound after an exposure and this switch closure may enable the next exposure through input B1 and a battery having sufficient charge for the exposure such as to drive a flashbulb or for operation of the camera electronics may interlock the exposure with a signal input to terminal B2. Many other interlocks may be provided hereto. Exposure control pulse Q may be processed with conventional electronics such as with operational amplifier 1532 exemplified by the Fairchild 709 or 741 amplifiers. The amplitude of output pulse 126B may be controlled with variable input resistor RI and a variable feedback resistor RF to establish gain of amplifier 1532 and therefore to establish amplitude of output pulse 126B. Further, variable resistor RB may bias output pulse 126B to a desired level. The input signals to amplifier 1532 may be connected to the negative input terminal as shown in FIG. 15D or conversely may be connected to a positive input terminal using well-known differential amplifier techniques.

Control potentiometers RI, RF, and RB may control the aperture function; where the amplitude and bias of signal 126B to feedback servo 1502 may control excitation signal 133 and therefore control the radius of transparent area 1505 (FIG. 15C). For example, the bias signal controlled with resistor RB may define the steady state excitation magnitude of signal 126B which may be adjusted to cause transparent area 1505 to have zero radius or to cause illumination amplifier 104 to be fully opaque to provide the shutter function in the absence of a pulse Q from multivibrator 1530. Control potentiameters RI and RF may be used to control amplitude of control pulse 126B, wherein the amplitude of pulse 126B controls the radius of transparent area 1505 and therefore controls the function of an aperture control illumination amplifier 104 for a camera system. It should be recognized that there may be interaction between the bias controls and amplitude controls relative to aperture size. Therefore, control RB may be a factory setting, control RI may be a factory setting, and control RF may be an operator-determined aperture control setting.

Multivibrator 1530 may be relatively insensitive to false triggering such as jitter or bounce of switch 1531 and the output of multivibrator 1530 may be independent of further transitions of the inputs once fired and may be a function only of timing conponents CE and RT, where well-known circuits for switch debounce may not be necessary.

The S/N 74122 multivibrator may be adjusted from a 40-nanosecond to a 28-second exposure time and may be further extended in exposure time by proper selection of components CE and RT. It may be desirable to limit the exposure time delay to a minimum of one millisecond rather than the 40-nanosecond time, which can be provided with fixed series and parallel reisitors connected between terminals C and R/C and connected with conponents CE and RT in well-known parallel and serial combinations. The output pulse may be terminated such as with feedback signals 132 and 133 or other signals such as integration signals 956 and 120 as discussed with reference to FIG. 9C in U.S. Pat. No. 3,986,022; where a threshold comparitor circuit such as the Fairchild 710 may detect a desired threshold amplitude and generate a clear signal. Alternately, the S/N 74122 multivibrator has a retriggerable capability wherein well-known circuits may be provided for retriggering multivibrator 1530 to generate longer output pulses Q and Q. Such multivibrators are discussed in the TTL Data Book For Design Engineers by Texas Instruments Inc, copyright 1973; particularly at pages 82 and 134-140 therein and herein incorporated-by-reference.

An audience display system has been described in U.S. Pat. No. 3,986,022 wherein improvements thereto are presented hereinafter.

An audience display system implemented in a transmissive mode such as being back-lighted with floodlights is enhanced if the floodlight illumination is evenly dispersed over the display area. Therefore, another inventive feature is related to including a device for evenly dispersing illumination over an audience display arrangement in particular and over an electro-optical device in general. Practical systems provide relatively even distribution, but it should be recognized that perfection in uniformity of distribution may not be practically achievable. Therefore, it is herein intended that terms relating to uniform distribution mean good distribution of illumination. In one embodiment, use of floodlight type devices or other wide beam device provides good distribution of illumination. In a further improved embodiment, an illumination distribution device may be placed inbetween the illumination source and the electro-optical device such as a screen for illumination distribution that may be composed of frosted glass, lucite, or other illumination conducting and distributing devices.

Various features of the present invention may be used in an environment that has changing ambient light conditions such as for an outdoor display that may operate in an outdoor environment having daytime and nighttime conditions and further having varying sunlight conditions in the daytime. As discussed in U.S. Pat. No. 3,986,022; an electro-optical device may operate with ambient illumination (not artificial illumination) when ambient illumination such as sunlight is sufficiently intense. When ambient illumination is not sufficiently intense, the electro-optical device may operate in conjunction with artificial illumination such as with floodlights. An electronic control may control artificial illumination as a function of natural illumination. For example, in the simplest implementation a manual switch may be provided to turn-on the artificial illumination when the natural illumination is not sufficiently intense. Alternately, an automatic system may be implemented such as with a photosensor detecting ambient illumination and controlling the intensity of artificial illumination. This embodiment may be better understood with reference to FIG. 1 as discussed below.

Photosensor 134 may sense ambient illumination and generate feedback signals 114, 120, 124, and 139 with feedback signal processors 116 as feedback to command device 127 and signal processor 128 for controlling intensity of source 100, which may be a floodlight, as a function of ambient illumination. Similarly, amplifier 104 may be controlled as a function of ambient illumination with signal 133. Alternately, feedback transducer 134 may sense transmitted and/or reflected illumination 110 from amplifier 104 for controlling illumination amplifier 104 to maintain a desired intensity of signal 110 comprising either natural illumination, source illumination, or a combination of natural and source illumination.

In a further improvement, an audience display system may include a plurality of illumination sensors including an ambient illumination sensor and a controlled illumination sensor. The ambient illumination sensor may sense ambient illumination 110 to control source 100 with feedback signals 120 and 124 to processor 128 to generate source control signal 132. The control illumination sensor may sense controlled illumination 110 to control amplifier 104 with feedback signals 120 and 124 to processor 128 to generate amplifier control signal 133.

In the above-described control arrangements, command elements 127 and 128 may include a stored program digital computer, as discussed in the referenced related patent applications, wherein this computer may include a program to optimize intensity as a function of ambient illumination by controlling source 100 and illumination amplifier 104 to provide the desired optical effect. In this embodiment, computer 251 would receive feedback signals from sensor 134 comprising an ambient illumination sensor and a controlled illumination sensor for generating control signals 132 and 133 in response to an interrelationship between ambient and controlled illumination intensity.

Ambient illumination is herein intended to mean external illumination in the environment of the controlled device, background illumination, and generally external illumination that is not controllable in response to the illumination feedback signal and which may be controlled with the illumination amplifier arrangement of the present invention.

The audience display features of the present invention have been discussed with reference to a preferred embodiment using an electro-optical arrangement but the improvements are also applicable to other embodiments. For example, the improvements of feedback control, ambient illumination control, intensity control using pulsed width modulation, colored displays, and other inventive features may be used in conjunction with incandescent bulb displays and other displays, wherein it is intended that the features of the instant invention not be limited to an electro-optical embodiment.

The system of the present invention is directed to illumination control in a general and a broad conceptual form. For simplicity of discussion, illumination control devices have been characterized as illumination amplifiers, liquid crystal devices, electro-chemical devices, electro-optical devices, and many other well-known devices have been referred to in general form. These generally referred to well-known devices include electrochromic devices, electrophoretic devices, PLZT devices, and other devices for illumination control.

Control of transmissivity and reflectivity is discussed and claimed in the system of the present invention for devices such as liquid crystal devices, where the device may be either transparent or opaque but may not provide true reflectivity. As is well known in the art, the transmissivity characteristic provides for control of transmission of illumination by controlling the device to be transmissive or opaque. When operating in the reflective mode, a reflector may be provided to reflect illumination back through transmissive segments such as a reflective rear electrode for reflecting illumination transmitted through the transmissive liquid crystal material. Therefore, although reflectivity may be discussed in the context of reflective liquid crystals, etc, it is intended that the common reflective mode terminology pertaining to providing a reflector for reflective mode operation imply an auxiliary reflector if the illumination control device itself does not provide such reflective characteristics. Certainly, if the controllable material such as liquid crystal material provides directly controllable reflectivity, there may be no need for auxiliary reflecting structures.

It is herein recognized that extremely high intensity illumination may affect certain electro-optical and electro-chemical devices in a chemical or thermal manner that may be considered undesirable. For most intensities and for most materials, this may not be a problem. For very high intensities and for certain materials, the affect of energy levels adversely affecting the electro-optical devices must be considered and this consideration is herein recognized.

It is herein intended that the various inventive features set forth herein be usable in well-known illumination processing devices. For example, various inventive features including apertures, shutters, choppers, scanners, feedback control, etc. may be usable with well-known telescopes, microscopes, binoculars, and periscopes, and other illumination processing devices.

In accordance with another feature of the present invention, an arrangement is provided for removal of thermal energy from an illumination amplifier device, which may constitute removal of relatively large quantities of thermal energy. For example, projection arrangements illuminated with high intensity illumination may cause an illumination amplifier to absorb illumination energy to the degree where thermal considerations become important, wherein heat transfer methods disclosed herein and/or well known in the art may be used.

An illumination amplifier may be illuminated with high intensity illumination and may exhibit a thermal temperature rise in response to absorbed illumination energy. Some heat transfer may be provided through passive mechanisms inherent in substantially any implementation such as through radiation and through convection, but these inherent passive cooling mechanisms may not be sufficient. Therefore, supplementary cooling methods may be required. Many supplementary cooling methods are disclosed herein and/or are well known in the art. For example, forced air convection can be used such as with a fan blowing air over the surface of the illumination amplifier. Also, a heat exchanger can be used either independently or in combination with other methods such as in conjunction with forced air cooling and/or in conjunction with fluid cooling. Forced air cooling can be provided with a well-known blower. Fluid cooling can be provided by circulating cooling fluid through a heat exchanger. Commercially available cooling elements can be used such as commercially available fans; heat exchangers; fluid cooling arrangements such as chilled water, nitrogen, freon, air, or other cooling fluids or gases; and other cooling arrangements. Also, a radiation median such as a cool radiation receiver can be provided for radiant cooling of the illumination amplifier. Many other methods will become obvious from the teachings herein.

Thermal design is well known in the art and may be applied to the arrangement of the present invention from the teachings herein. This is exemplified with the articles by McNeal and Gordon and by Leonard and Axelband referenced herein and with multitudes of textbooks, articles, and other publications in the public domain.

Controls for heat transfer devices are well known in the art and may include electronic, mechanical, and/or other control devices. For example, mechanical controls are well known for automobile cooling systems and for household refrigerators, electro-mechanical controls are well known for air conditioners and for household heating systems, electronic controls are well known for ovens, and many different types of controls are well known for many applications. In view of the above, well-known thermal controls may be used with the embodiments set forth herein and therefore may not be further discussed herein for a particular embodiment; but are intended to be implicit herein as will become obvious from the teachings herein.

Prior art systems using illumination amplifier devices are not concerned with heat generated by the illumination amplifier device (IAD) because of the low illumination power levels used in prior art systems. For example, prior art liquid crystal devices (LCDs) are inherently low power devices and therefore with prior art systems there has been no concern for heating due to electrical excitation. Further, prior art LCDs operate in relatively low intensity illumination environments such as in sunlight or with low intensity illumination sources for nighttime viewing such as provided with well-known LCD watch displays. Therefore, the prior art is not concerned with thermal effects of the incident illumination or of the electrical excitation.

LCDs are affected by ambient temperatures, wherein the response is slowed at low temperatures and the display is degraded at high temperatures. Ambient temperature operation is considered by the prior art to be a requirement, wherein thermal considerations are limited to merely placing a constraint on the operating environment. For example, LCDs are specified for operating in a limited ambient temperature environment such as from 0.degree. C. to 70.degree. C. The prior art does not in any way provide arrangements for cooling LCDs or other IADs because the prior art does not use LCDs in arrangements that might provide significant heating effects or in arrangements that operate at environmental temperatures outside of the specified LCD operating regions.

In accordance with the instant feature of the present invention, a thermal control arrangement is provided to permit IADs to tolerate high energy illumination and/or excitation and/or to operate in ambient temperature environments outside of the specified operating region for IADs. The need for such thermal control arrangements has not been acknowledged by the prior art because the prior art is unaware of uses that could exceed the thermal specifications of the IAD and/or extend the use of IADs beyond the specified operating region. For example, in accordance with the projection display arrangement of the present invention, an IAD can be illuminated with high intensity illumination for projection of high intensity large screen displays. High intensity illumination causes heating of the IAD and therefore could require thermal design considerations. Because the prior art does not consider such projection display arrangements, the prior art has not been concerned with high intensity illumination nor any need to cool an IAD exposed to high intensity illumination.

For simplicity of discussion, the thermal design feature of the present invention will be discussed for a liquid crystal device (LCD). It is herein intended that any reference to an LCD be interpreted as a reference to a generalized illumination amplifier device.

In a preferred embodiment, a projection IAD is provided, operating in a reflective mode, having heat transfer devices as discussed hereinafter, and being illuminated by high intensity illumination. The prior art does not consider heat transfer devices, nor projection arrangements for IADs and certainly not in combination with reflective mode operation.

Although the preferred embodiment of a heat transfer device is related to cooling of an IAD, it will become obvious from the teachings herein that a heating arrangement for heating an IAD can be implemented therefrom. Therefore, it is herein intended that any reference to heat transfer, cooling, etc be interpreted as a reference to a generalized heat transfer arrangement for cooling, heating, etc.

Further, heat transfer means and methods are discussed herein for different preferred embodiments, wherein it is herein intended that any heat transfer arrangement discussed herein may be used in combination with any other heat transfer arrangement and with any IAD arrangement.

Yet further, heat transfer advantages are discussed herein for IAD, LCD, and filter arrangements; wherein it is herein intended that this reflective mode heat transfer arrangement be applicable to illumination devices in general including lens, filters, etc as exemplified by IAD, LCD, and filter arrangements herein.

Heat transfer can be provided in the form of radiant, convective, and/or conductive heat transfer and can be enhanced with devices that improve radiation, convection, and conduction.

An IAD can be operated in a transmissive mode or in a reflective mode, wherein heat transfer arrangements for a transmissive mode IAD has more constraints than for a reflective mode IAD. For a transmissive mode IAD, both sides of the IAD are unobstructed to permit transmission of the illumination from one side to the other side. For a reflective mode IAD, illumination is reflected from the same side that is illuminated with the incident illumination. Therefore, the back side or rear side (opposite from the illuminated side) of a reflective mode IAD is available for heat transfer devices. This provides a significant advantage over transmissive mode arrangements because heating affects due to high intensity illumination are concentrated on the illuminated portions of the IAD, wherein heat transfer from the back side of the IAD is therefore significantly more efficient.

For a transmissive mode IAD, both the front and the back of the IAD must be relatively transparent to illumination, thereby minimizing the location of thermal devices. For a reflective mode IAD, the back of the IAD does not have to be transparent and therefore can provide convenient mounting for heat transfer devices. Mounting of heat transfer devices on the back of a reflective mode IAD brings the heat transfer device into very close proximity with the illuminated front face of the IAD. Because the front face of the IAD typically exhibits the worst case heating condition, such a reflective mode rear cooled IAD permits a more efficient thermal design. Therefore, in a preferred embodiment, a reflective mode IAD is provided having a heat transfer arrangement mounted on the rear or back side of the IAD to enhance heat transfer.

Experience indicates that providing heat transfer from the back side of a reflective mode IAD is about ten times better than providing heat transfer from the edges or outside periphery of an IAD, wherein such an order of magnitude improvement is very significant.

Natural radiation, convection, and conduction provide some cooling for IADs, but such heat transfer may not be adequate for many uses. For example, substantially any device transfers radiant energy to or from the external environment and provides some heat transfer due to free air convection and due to conduction through a mounting structure or other contact structure. Such heat transfer may be significantly enhanced with the proper heat transfer devices.

One method of heat transfer is to provide forced conduction cooling such as by blowing air at the IAD for cooling. This arrangement has advantages, wherein cooling air is transparent to illumination and therefore can be directed at the front face of the IAD or at hot spots on the IAD for optimum cooling. Further, forced air cooling is inexpensive and effective for many applications. Disadvantages include the primary disadvantage that it may be undesirable to provide a fan or other such device in many types of systems such as small portable systems characterized by a calculator or an electronic toy. Further, a blower consumes a relatively large amount of electrical energy compared to the excitation energy for an IAD, thereby degrading battery life for portable battery operated systems. Yet further, blowers have disadvantages such as requiring dust filters, ducting, etc. In view of the above, a blower heat transfer device is acceptable for many IAD applications, but a conductive heat transfer device provides important advantages for other IAD applications.

Although an IAD is herein intended to be generally interpreted in a broad context, an illumination amplifier may be exemplified with an LCD in a preferred embodiment to provide a simple illustration of the features of the present invention. Various arrangements of the heat transfer arrangement for illumination amplifiers will now be discussed in the embodiment of an LCD arrangement with reference to FIG. 16, which is herein intended to be exemplary of the broad scope of illumination amplifier arrangements.

Various embodiments of cooling arrangements are shown in FIGS. 16A-16D. These arrangements show LCD 1610 being illuminated by incident illumination 1611 which is transmitted as transmitted illumination 1612 and/or reflected as reflected illumination 1613. LCD 1610 may be heated such as by absorbing incident illumination 1611, by heat dissipation due to electrical excitation, by ambient conditions, etc. Inherent cooling is provided by radiation 1615 such as to the external environment, convection 1616 such as to the air, and/or conduction 1617 such as to a mounting structure.

Forced air cooling can be provided with blower 1618 generating forced air 1619 to cool LCD 1610. Blower 1618 can be any well-known blower including fans, etc and can include devices such as plenums, tubing, etc to facilitate cooling.

Conductive cooling can be provided as shown in FIGS. 16B-16D. Conductive devices 1621 and 1622 (FIG. 16B) and/or device 1623 (FIG. 16C) and/or device 1624 (FIG. 16D) can be placed in contact with LCD 1610 having edge 1620, illustrated to provide an isometric perspective. Conductive devices 1621-1624 can be placed in contact with LCD 1610 in a manner that provides good thermal contact such as by providing flat contact surfaces, thermal conducting adhesives, thermal conducting contact materials, thin contact materials and/or various well-known thermal contacting methods and devices. Conducting devices can be provided around the periphery of LCD 1610 such as "picture-frame" type devices 1621 and 1622 (FIG. 16B) and/or edge type devices 1623 (FIG. 16C). Such picture-frame and edge devices permit transmission of illumination 1611 through a portion of the center of LCD 1610 to provide transmitted illumination 1612. Such devices can be mounted near the edge of LCD 1610 for minimum obstruction of incident illumination 1611, such as shown with conducting devices 1622 (FIG. 16B) and 1623 (FIG. 16C) or alternately such conducting devices can be mounted on the side of LCD 1610 opposite the side receiving incident illumination 1611 such as illustrated with conducting device 1621 (FIG. 16B).

The arrangements shown in FIGS. 16A-16C can be used with transmissive or reflective mode LCDs, wherein the back side of LCD 1610 (the side opposite the side illuminated with incident illumination 1611) is not obscured with heat transfer devices thereby permitting transmissive mode operation.

In accordance with a preferred embodiment of the present invention, a reflective mode IAD is provided having improved heat transfer capability, as will be discussed with reference to FIG. 16D. LCD 1610 can operate in a reflective mode having controlled reflection of incident illumination 1611 as reflected illumination 1613. Because of the reflective mode of operation, transmission of incident illumination 1611 through LCD 1610 and through the back side of LCD 1610 is not required. Therefore, the back side of LCD 1610 is available for heat transfer devices. Because the thickness of edge 1620 of LCD 1610 is small relative to the dimensions of the planer faces, heat transfer to the back side is significantly more efficient than heat transfer to the edges. This can be seen in FIGS. 16B and 16C, where illumination incident upon the center of LCD 1610 is conducted by LCD 1610 to the outer edges to be conducted away with conduction devices 1621-1623. Conversely, with the arrangement shown in FIG. 16D, heat need only be conducted through the relatively thin LCD 1610 to the back side to be conducted away with conduction device 1624. For prior art LCDs, the thickness may only be ten percent or may be only one percent of the face dimensions, thereby providing possibly a factor of 10 to 100 times improvement in heat transfer capability from the back side. Therefore, for many applications where heat transfer efficiency is important such as for high intensity illumination for projection displays or where simple conduction without forced air or exotic cooling methods is important such as for hand-held calculators and electronic games, the arrangement shown in FIG. 6D represents a preferred embodiment having significant advantages over other arrangements.

Conduction devices 1621-1624 can be simple thermal conduction devices such as metal devices or can be heat sinks, fluid cooling devices, thermoelectric coolers, or other known cooling arrangements. Heat sinks such as finned heat sinks are manufactured by many companies such as the Vemaline Division of Astby and Barton Co. of Warwick R.I. and Wakefield Engineering Inc. of Wakefield MA. Thermoelectric coolers such as Peltier coolers are manufactured by many companies such as Melcore of Trenton N.J. (FRIGICHIP and FRIGITOTE) and Frigidheat (Model 45M-10X). Several conduction devices will now be discussed, which are exemplary of the more general conduction arrangements of the present invention.

Conduction devices 1621-1624 can be heat conductive mounting structures that conduct heat away from LCD 1610. Such devices can be heat sinks that absorb heat energy or that conduct heat energy away from LCD 1610 for better heat transfer. In one embodiment, heat conductive devices are connected to the case or other structure of a display arrangement for heat transfer from the case to the air through free air convection. In another embodiment, conduction devices are known heat sinks such as having fins and other structures for efficient heat transfer to the air through convection. In another embodiment, a blower is used to improve heat transfer from the heat conduction device to the air. In yet another embodiment, cooling fluid is circulated through the heat conductive device to conduct heat away from LCD 1610. For example, forced air 1619 from blower 1618 (FIG. 16A) can be blown into or through heat conductive devices 1621-1624 as illustrated with arrow 1625. Alternately, arrow 1625 can exemplify cooling fluid such as freon. Further, heat conductive devices 1621-1624 can have fins or other arrangements for efficient heat transfer.

Several heat transfer arrangements are shown in FIG. 16E that can be used for heat transfer devices 1621-1624 (FIGS. 16B-16D). Heat transfer devices 1621-1624 can be heat sinks having fins 1626 for heat conduction, heat sinking, heat transfer to the air, etc. Heat transfer can be enhanced with blower 1618 generating forced air 1619. Heat transfer can be enhanced with cooling fluid flow such as with cooling tube 1628 having coolant 1627 entering and coolant 1629 exiting such as with well-known coolant devices. One well-known cooling fluid device is an automobile radiator. Another well-known cooling fluid device is a common household refrigerator or air conditioner having cold freon or other coolant circulated through cooling coils. Cooling coils 1628 can be used in combination with heat sink 1626 to further improve cooling such as with an automobile radiator, a refrigerator, and an air conditioner.

Cooling can be provided with thermoelectric coolers, where elments 1621-1624 can be thermoelectric coolers mounted or bonded directly to LCD 1610. Alternately, a thermoelectric cooler can be used for cooling heat sink material which conducts heat from LCD 1610 to the thermoelectric cooler, shown with heat sinks 1621-1624. Other cooling arrangements that can be used include dewars, conventional refrigerators, Peltier coolers, and other known cooling devices.

In an alternate embodiment, electro-optical material in IAD 1610 can be circulated through a coolant device such as a refrigerator, heat exchanger, etc for cooling. In this embodiment, IAD 1610 contains electro-optical material that flows under control of a pump, convection forces, or other mechanisms; wherein the fluid can flow out of IAD 1610 to be cooled and can flow back into IAD 1610 when cooled for control of illumination 1611.

A preferred embodiment 1600 of an integral batch-fabricated display arrangement of the present invention is shown in FIG. 16F. Arrangement 1600 provides a batch-fabricated configuration having integral and/or implicit structural and cooling capability in a simple, effective, and inexpensive arrangement.

In FIG. 16F, incident illumination 1611 is generated with source 1634. Source 1634 can include devices that are well known in the art such as bulbs, reflectors, lenses, etc as with prior art slide projector and movie projector arrangements and as discussed with reference to FIG. 14. Source illumination 1611A is processed with heat filter 1636 for enhancing the visibility-to-heat ratio (VHR) of illumination 1611. Filter 1636 may be a well-known heat filter such as for filtering out infrared energy. Filter 1636 can be mounted on structure 1637 for conducting absorbed heat energy from filter 1636 to case 1632. Filtered illumination 1611B is incident upon IAD 1610, generating reflected illumination 1613. IAD 1610 can be operated in a reflective mode, generating reflected illumination 1613. IAD 1610 can be attached to case 1632 such as with bonding material 1630 which can be a good heat conductive material. Various attachment methods are discussed herein and/or are well known in the art.

LCD 1610 can be bonded to heat sink 1632 with a thin thermally conductive bonding material 1630, where heat sink 1632 can be a part of the enclosure of an illumination display device. Case 1632 can provide a heat sink for conducting heat energy from illumination amplifier 1610; for dispersing heat energy throughout the case; and for radiant, convective, and conductive cooling to the outside environment, as illustrated with arrows 1615-1617. Further, fins or other heat sinking 1633 and heat transfer devices can be provided on case 1632 to enhance heat transfer. This can be considered to be a batch-fabricated case, mounting structure, and heat transfer media to facilitate protection, mounting, and cooling respectively of illumination amplifier 1610.

Reflected controlled illumination 1613A can be processed with projection optics 1638 to generate projection illumination 1613B for projection onto screen 1635 as discussed with reference to FIG. 14 herein. Projection optics can include lenses, prisms, and other arrangements and can have focusing, zooming, and other capabilities well known in the projection optics art; as further discussed with reference to FIG. 14 herein. Case 1632 can provide heat sink capability such as for dissipating heat through radiation 1615, convection 1616, and conduction 1617. Finned heat sink 1633 can be used to enhance heat transfer such as with convection heat transfer 1616.

The projection IAD arrangement shown in FIG. 16F can be used in multitudes of different types of systems. In one embodiment, system 1600 can be used as a toy or a game for providing a large screen display. In another embodiment, system 1600 can be used as an advertising display such as an illuminated display in a store. In yet another embodiment, system 1600 can be used as a large screen information display such as to replace well-known clock displays, temperature displays, propogating information displays, scoreboard displays, billboard displays, etc. In yet another embodiment, system 1600 can be used as a portable television display or other pictorial display such as discussed with reference to FIG. 14 herein. In yet still another embodiment, system 1600 can be used as a light organ display such as for projecting colored illumination in response to audio signals. In yet still another embodiment, system 1600 can be used as a display for interactive operator communication with a computer. And in another embodiment, system 1600 can be used as an equipment display such as in numerical control systems; machine systems; vehicular systems including sea, ground, air and space vehicles; and many other equipment systems.

System 1600 is shown implemented with a passive cooling arrangement (FIG. 16F) that does not dissipate electrical energy for cooling such as with conductive and free air convective cooling. This arrangment is particularly advantageous, wherein a low power arrangement can be provided because of the low power requirements of IAD 1610, and the low power (or no power) cooling requirements.

Further, the arrangement shown in FIG. 16F can be a miniature arrangement, wherein screen 1635 can be an external screen such as a well-known detached movie projector screen, a wall, etc and therefore arrangement 1600 excluding screen 1635 can be implemented in miniature form. In order to preserve the miniature form and low power characteristics, it is desirable to minimize active (power dissipating) heat transfer devices such as fans, refrigeration, thermoelectric coolers, etc. In an alternate embodiment not having constraints such as power, size, etc; system 1600 can be implemented with active cooling arrangements such as forced air cooling, fluid cooling, thermoelectric cooling, etc to enhance thermal considerations. Although cooling simplicity is important for many applications, other applications may require high intensity and/or large size projected images; wherein high intensity and large size require high intensity illumination from source 1634. In such applications, exotic cooling techniques may be permissable in order to achieve the high intensity and/or large size projected image on screen 1635. Such exotic techniques may include circulating the electro-optical filler material 1659 (FIG. 16G) for coolant with an external refrigeration coolant device, implementing the IAD substrates to include coolant coils contained therein, implementing the internal IAD space to include coolant coils circulated therein, implementing the IAD with a heat pipe, etc.

Heat pipe technology may be used for IAD heat transfer. Such a heat pipe is characterized by the RCA Corp heat pipe product discussed in the OCt. 27, 1977 issue of Electronics Magazine at page 50 therein.

A heat shield or filter can be used to further reduce heating effects. Illumination in the higher frequency or blue and violet spectral region is more effective for displays and reduces heating compared with illumination in the red and orange spectral region, wherein this red and orange spectral region is only moderately effective for displays and produces more pronounced heating effects. Therefore, in embodiments where heating effects are important, higher frequency visible illumination such as in the blue and violet regions having a higher visibility-to-heat ratio (VHR) is more desirable than lower frequency visible illumination such as in the red and orange regions having a lower VHR. A method for spectral selection can be implemented in various ways such as by selecting illumination sources that generate illumination towards the higher VHR spectral region; using filters that remove illumination having a lower VHR such as heat filters, infrared filters, and red filters; and other methods and arrangements for reducing portions of the spectrum having a lower VHR and enhancing spectral regions having a greater VHR.

In one such embodiment, source 1634 includes a source for generating illumination having a higher VHR such as a mercury vapor lamp, a fluorescent lamp, a xenon lamp, etc as preferred to lower VHR lamps such as incandescent lamps; although such lower VHR lamps are not precluded in alternate embodiments.

In another such embodiment, heat filler 1636 removes lower VHR spectral energy from input illumination 1611A and transmits more of the higher VHR spectral energy as filtered illumination 1611B. Heat filter 1636 can be used and can be any known filter such as an infrared filter for reducing infrared energy which has a low VHR. Filter 1636 can remove a higher percentage of red and orange spectral energy having a relatively low VHR and can pass a higher percentage of blue spectral energy as signal 1611B having a higher VHR. Heat filter 1636 can absorb large amounts of illumination energy from input illumination signal 1611A for conversion to heat energy, wherein filter 1636 can be mounted on a heat sink 1637 to conduct heat energy to case 1632 or can dissipate heat energy in other forms such as with radiant, convective, and conductive cooling as discussed with reference to FIGS. 16A-16E herein.

Alternately, heat filter 1636 can be operated in a reflective mode rather than a transmissive mode, wherein filter 1636 can transmit and/or absorb over VHR illumination and can reflect higher VHR illumination such as by transmitting and/or absorbing infrared and red spectral region illumination and by reflecting blue and violet spectral region illumination. In this embodiment, the heat transfer advantages associated with reflective mode LCD 1610 also pertain to a reflective mode filter. Further, transmitted filter illumination can be transmitted to a heat absorbing medium or can be transmitted to the external environment to reduce heating effects. Alternately, filter 1636 can transmit higher VHR illumination to LCD 1610 and can reflect lower VHR illumination to a heat absorbing medium or to the external environment.

In a preferred embodiment, heat transfer arrangements are discussed with reference to IAD 1610. Other devices such as source optics 1634, filter 1636, projection optics 1638, etc may experience heating effects and may require cooling, wherein the cooling arrangements discussed for LCD 1610 are equally applicable to the other elements in the system and wherein these cooling arrangements may be used in any combination with the elements shown in FIG. 16F. For example, source optics 1634 may be cooled with forced air 1619 from blower 1618 (FIGS. 16A and 16E), filter 1636 may be cooled conductively with conductive mounting 1637 (FIG. 16F), illumination amplifier 1610 may be cooled with heat sink 1633 (FIG. 16F), projection optics 1638 may be cooled with a freon refrigerator, and screen 1635 may not be cooled explicitly but may be cooled implicitly with free air convective cooling; or alternately, many other combinations and permutations of heat transfer arrangements may be provided.

In a preferred embodiment of a bonded IAD arrangement, the bonding material is a good heat conductor and is relatively thin to optimize heat transfer. In prior art arrangements, the mounting device is relatively thick and does not provide good heat transfer. For example, prior art systems use non-conductive epoxy in a relatively thick form. Also, prior art systems such as LCD electronic watches use a pressure contact called a "zebra strip" for contacting the electrode points with electrically conductives bumps, but providing poor thermal conductivity due to the limited contact area, poor thermal conductivity, etc and being relatively thick. Therefore, it is apparent that the prior art is unconcerned with heat transfer considerations.

Although the arrangement shown in FIG. 16 has been discussed in the embodiment of an arrangement for cooling an IAD, these arrangements can also be used for heating an IAD such as for operation at low temperatures. For example, heat conducting devices 1621-1624 can alternately be heating devices for conducting heat to IAD 1610. Further, fluid flow 1625 (FIGS. 16B-16D) and fluid conductor 1628 (FIG. 16E) can be used for heating IAD 1610. Alternately, electrodes such as for exciting liquid crystal material can be resistive electrodes which may be transparent or non-transparent for heating liquid crystal material for operation at low temperature conditions. Heating arrangements as described herein may be thermostatically controlled such as with electronic controls to heat liquid crystal material to maintain a temperature above the low temperature operating threshold.

Thermal considerations can be further enhanced by proper construction of an IAD element, wherein a preferred embodiment thereof will now be discussed with reference to FIG. 16G. The arrangement shown in FIG. 16G is discussed in greater detail herein under the title LARGE PANEL CONSTRUCTION. Illumination 1611 is shown incident on IAD 1641 operating in a reflective mode. Reflected illumination 1613 is generated under control of IAD 1641 such as by having a reflective surface at the lower surface 1655 or at the outer surface 1645. Base 1655 provides for mounting, cooling, and/or providing a reflective surface.

Heat transfer can be improved by having heat conducting materials such as upper substrate 1644, lower substrate 1645, and filler material 1659. Upper substrate 1644 and lower substrate 1645 can be constructed of heat conductive material such as glass, plastic, and other materials that are fabricated in a form to provide good heat conduction. Such substrate materials are transparent materials in a preferred embodiment, but may be other than transparent materials. For example, operating in a reflective mode, electro-optical device 1641 can have a reflective coating on the inside of substrate 1645 such as at inside surface 1653, wherein transparency of lower substrate 1645 may not be an important consideration. Therefore, bottom substrate 1645 can be a non-transparent heat conductive substrate such as a metal substrate or other substrate having good heat transfer characteristics.

Further, IAD 1641 can have a plurality of heat transfer devices such as discussed with reference to FIGS. 16A-16E, used in combination with the preferred embodiment of a reflective mode IAD having a good heat transfer backing 1655. For example, IAD 1641 can have a picture frame type heat transfer structure on top electrode 1644 such as structure 1622 (FIG. 16B), can have fluid flow cooling such as illustrated with arrow 1625 (FIGS. 16A-16D) and with arrows 1627 and 1629 (FIG. 16E), etc in combination with heat filter 1636 and heat conductive mounting of IAD 1610 (FIG. 16F) and other arrangements described herein in various combinations. Further, IAD 1641 can have a heat conductive filler material 1659 to enhance heat transfer such as using a filler material that has an inherently good heat conductive characteristic and/or by including material in filler 1659 to enhance the heat conductivity characteristic.

Yet further, filler material 1659 can be circulated either internal to IAD 1641 or external to IAD 1641. Internal circulation can be provided with an internally mounted agitator, pump element, etc; by including magnetic particles with the filler material and inducing a magnetic field to cause fluid flow; by implementing fluid flow caused by differences in temperature such as used in self-cooling oil-filled electrical transformers; and other methods that will now become obvious from the teachings herein. External heat transfer can be provided in combination with the above methods and arrangements or independent thereof. Pipe 1656A can introduce cooled fluids 1627 into IAD 1641 and pipe 1656B can extract heated fluids 1629 from IAD 1641. An external pump, convective cooler, or other arrangement can be used to induce fluid flow 1627 and 1629 for cooling. The pipe comprising input segment 1656A and output segment 1656B can be routed to a heat exchanger such as a heat sink 1633 (FIG. 16E) for heat transfer to the air, or to a coolant heat exchanger, or to other heat transfer devices.

The structure of substrates 1644 and 1645 (FIG. 16G) can be constructed in a manner that improves heat transfer. For example, top substrate 1644 can be a thin substrate having a thin dimension 1657 to minimize illumination absorbtion and to minimize related heating effects. Bottom substrate 1645 can be thicker than top substrate 1644 because bottom substrate 1645 is closer to heat sink 1655 and therefore provides better heat transfer. Further, inner surface 1653 of bottom substrate 1645 can have a reflective coating, thereby significantly reducing illumination transmission through bottom substrate 1645 and the related heating effects.

Where illumination absorbtion of filler material 1659 is an important consideration, it may be desirable to maximize heat transfer between filler material 1659 and heat sink 1655. Therefore. lower substrate 1645 may be thinner than upper substrate 1644 to enhance heat transfer from filler material 1659 to heat sink 1655. In yet another embodiment, upper substrate 1644 may have a thickness equal to or substantially the same thickness as lower substrate 1645 such as to combine the advantages of a thinner upper substrate 1644 and a thinner lower substrate 1645. Therefore, heat transfer can be enhanced having a thinner lower substrate 1645, or a thinner upper substrate 1644, or equally thin substrates 1645 and 1644. Thinness is herein intended to mean the dimension transmitting illumination and/or the substrate dimension shown as cross-hatched upper dimension 1657 and lower dimension 1658.

Further cooling advantages can be achieved with evaporation, wherein evaporative cooling is highly efficient. For example, fluid can be controlled to flow over or be sprayed over heat sink 1633 in a manner that causes evaporation such as is well known in the art for evaporative cooling. Similarly, fluid can be caused to flow over or be sprayed over the surface of LCD 1610 to cool the surface having incident illumination 1611, such as top surface 1644 of illumination amplifier 1641 (FIG. 16G). In one embodiment, a fine mist can be sprayed over top surface 1644, wherein the fineness and amounts of the spray may be such that illumination degradation is minimal and cooling such as through evaporation and mist effects is enhanced.

Still further, a plurality of liquid crystal elements 1610 can be sequentially rotated into position such as on a rotating disk or cylinder so that each element is illuminated in sequence to provide the desired projected image. The percentage of the energy absorbed by each element is related to the number of elements and therefore the heating of any element can be significantly reduced. Such an arrangement is exemplified with a moving picture projector, where a plurality of frames of the film are rotated into the illumination beam. As the IAD is rotated out of the illumination beam, it can be cooled such as with the various methods discussed above. Therefore, when the IAD is rotated back into the illumination beam, it has been sufficiently cooled to reduce thermal degradation effects. More latitude is permitted in cooling of IADs that are not in the illumination beam because there is reduced concern for degradation of the projected image until the IAD is rotated back into the illumination beam. For example, IADs rotated out of the illumination beam can be sprayed with a mist for cooling, passed through a wiper assembly to remove unevaporated mist, and then rotated back into the illumination beam. Similarly, IADs rotated out of the illumination beam can be rotated through a water bath or other coolant, passed through a drying assembly, and then rotated back into the illumination beam.

Cooling is particularly enhanced with high velocity flow, with evaporation, and by covering a large area. For example, forced air 1619 from blower 1618 and fluid 1627 and 1629 flowing in pipe 1628 (FIG. 16E) may have high velocity flow and may cool a large area. Heat sink 1633 may cover a larger area than illumination amplifier 1610 for more efficient heat transfer to the air 1616 (FIG. 16F) and air 1616 (FIG. 16F) may be high velocity air 1619 generated with a high velocity blower such as blower 1618 (FIGS. 16A and 16E).

Still further cooling advantages can be achieved with fluid circulation. For example, prior art arrangements have been configured for recirculating the illumination control fluid to reduce or avoid agglomeration of the particles (U.S. Pat. No. 3,788,729) but not to provide cooling. In such prior art arrangements, heat is applied to the fluid to provide convective flow, thereby specifically precluding the objective of the present invention for providing cooling. Nevertheless, such prior art arrangements may be used for cooling in accordance with the arrangement of the present invention such as by convective flow, pumped flow, etc and having external heat transfer means to remove heat from the circulating fluid.

Yet further, closed system heat exchangers are well known and can be used with the system of the present invention. Such devices are exemplified by an automotive transmission fluid cooling system having a heat transfer arrangement in conjunction with a radiator. Transmission fluid is circulated through a closed cooling system to prevent contamination and to provide cooling of the transmission fluid. The transmission fluid is circulated through a heat exchanger such as heat exchanger 1633 (FIG. 16E) and is cooled by convective air flow from the radiator and by forced air flow generated with the automobile fan such as illustrated with blower 1618. In some applications, transmission fluid can be circulated through the cooling water in the automotive radiator, wherein the integrity of the transmission fluid cooling system is preserved by conducting the transmission fluid through a sealed pipe such as pipe 1628 (FIG. 16E).

Yet further, an illumination amplifier substrate can provide cooling such as with deposited metalic thermal conductors either using the conventional metallic deposited electrodes or using supplementary thermal conductors deposited or otherwise formed on substrates of amplifier 1641. Similarly, other cooling methods may be provided as an integral part of IAD 1641 such as coolant tubes 1628 formed in the substrate 1643 of amplifier 1641 for circulating cooling fluid to remove heat.

It is herein intended that the heat transfer considerations described for the preferred embodiment of a projection LCD arrangement also be usable with the other embodiments disclosed herein. For example, an IAD window may be subjected to heat and cold environmental conditions, wherein the heat transfer embodiments disclosed herein may be used for heating a cold IAD window and/or cooling a hot IAD window.

Although high intensity and large size terminology pertaining to displays are relative terms, they are self-explanatory and do characterize the projection IAD arrangement of the present invention.

Although terminology such as high intensity illumination is not quantitative, it is illustrative in accordance with the improvement of the present invention. For example, prior art liquid crystal displays use ambient light such as room lighting in a home, which is considered to be low intensity illumination. Further, prior art liquid crystal watches use a very small light bulb for nighttime viewing, which is also considered to be low intensity illumination. Yet further, prior art liquid crystal displays use sunlight but are viewed in indirect rather than direct sunlight, which is considered to be low intensity (and natural) illumination. Use of a high intensity source (not natural illumination) in combination with a projection display arrangement characterized one feature of the present invention.

In alternate embodiments, a high intensity IAD display may be characterized as a display that is illuminated with illumination from a source that is greater than ambient illumination; or an IAD display that is illuminated with illumination from a source that is greater than sunlight illumination; or an IAD display that is illuminated to provide greater than ambient display illumination; or an IAD display that is illuminated with illumination from a source that is at least a one-watt source, or is at least a four-watt source, or is at least a ten-watt source, or is at least a 100-watt source. Further, high intensity may be characterized as source illumination intensity that is greater than needed for direct viewing, wherein source illumination intensity needed for viewing a magnified projected image is greater than needed for direct viewing of an IAD because of the intensity reduction caused by projection and magnification.

In alternate embodiments, size-related projection terminology may be characterized with the table entitled SIZE RELATED ALTERNATE EMBODIMENTS; where the first column identifies an IAD dimension, the second column identifies a projected display dimension which may correspond to the related IAD dimension in the first column, and the third column identifies the projection magnification related to such correspondence. In order to broaden the example, the IAD dimensions in said first column are defined as "less than" dimensions, while the projected dimensions and projection magnification in said second and third columns are defined as "greater than" dimensions.

Large panels of electro-optical devices may be required such as for windows and large displays. For example, large panels can be implemented with liquid crystal material sandwiched inbetween glass substrates having deposited electrodes on the inner surfaces. Liquid crystal support is usually provided by contacts between the two glass substrates at the outer edges or periphery of a panel. For small panels, this edge support has been adequate. For large panels such as in accordance with the window and display embodiments of the present invention and for multitudes of other embodiments, it may be desirable to provide supports within the panel interior between the outer edges. Therefore, in accordance with another feature of the present invention, a panel arrangement is provided for construction of large panels such as with internal support elements.

The broad teachings of the present invention for constructing large photo-optical panels can be accomplished with many arrangements, some of which are discussed above. The teachings herein are very broad and are not limited to merely internal support structures, but include any generalized arrangement for implementing large panels.

A large panel element will now be discussed with reference to FIG. 16G in the embodiment of a large LCD panel. Panel 1641 is shown in simplified form for purposes of illustration of the improvements provided herein, wherein construction of small panels is well known in the art and provides a basis for this discussion on large panels. For example, substrate materials 1643 are shown in rectangular form having a cross-hatched section taken in the plane of the figure and having exaggerated spacing between the substrate for purposes of illustration. Panel 1641 can be implemented with electro-optical materials such as liquid crystal material filling space between sandwiched substrates 1643 which may be glass, plastic, or other substrates. Substrates 1643 comprise upper substrate 1644 and lower substrate 1645 bonded together at edge 1646. In the usual prior art configuration, substrates 1644 and 1645 are connected at the outer edges such as with support 1647 at the left side and support 1648 at the right side. Electrodes are provided such as on the inner surface 1652 of top substrate 1644 and the inner surface 1653 of bottom substrate 1645.

In accordance with one feature of the present invention, internal supports 1649-1651 are provided for supporting substrates 1644 and 1645 inbetween edge supports 1647 and 1648. Supports 1649 and 1650 are shown at the sectioned plane of the figure and support 1651 is shown set back from the plane of the figure. Supports 1649-1651 are shown in simplified form for convenience of illustration, wherein supports 1649-1651 may be small dimension or point supports such as support 1649, long ridge-type or barrier-type supports such as supports 1650 and 1651, or other types of supports for supporting substrates 1644 and 1645 inbetween outer edge peripheral supports 1647 and 1648.

Supports or spacers can be constructed as part of substrates 1644 and 1645 or can be attached to substrates 1644 and 1645 such as with bonding methods. For example, integral construction of supports as part of the substrates can be provided by well-known moulding, etching, grinding, milling, etc of substrates 1644 and 1645 to provide internal or intermediate supports or spacers 1649-1651. Alternately, substrates 1644 and 1645 can be constructed without internal supports, wherein internal supports can be attached during the bonding together of substrates 1644 and 1645. Alternately, supports such as supports 1649-1651 can be an inserted structure rather than a bonded structure. For example, such supports may be a thin honeycomb structure inserted between substrates 1644 and 1645 and either maintained in place by close proximity of the substrates or glued or otherwise bonded to the substrates to provide support and maintain separation between the substrates. Such a support structure is similar to the honeycomb structure for supporting and separating sheets or aircraft and missile surface "skin"; as is well known in the airframe structural art. Internal supports 1649-1651 can be a self-supporting internal structure such as a honeycomb or other structure inserted between substrates 1644 and 1645 and either bonded or not bonded thereto for providing the desired support. Many other techniques will now become obvious to those skilled in the art from the teachings herein.

For a honeycomb-type structure or other such internal supporting structure, the supports may be a barrier to the free flow of electro-optical material. This can be either desirable or undesirable, depending on the implementation. Where undesirable and where free flow of material is desired, ports or holes can be provided such as hole 1660 to permit flow of the material through supporting structure 1650.

Still further, many other techniques for providing support and maintaining separation for substrates 1644 and 1645 and many other arrangements for implementing large photo-optical panels will now become obvious to those skilled in the art from the teachings herein.

The embodiment shown in FIG. 16 clearly finds antecedent basis in parent U.S. Pat. No. 3,986,022; wherein projection optics are disclosed therein, reflective mode illumination amplifier operation is disclosed therein, and a large screen audience display is disclosed therein and wherein the combination of these disclosures is disclosed explicitly therein and/or is implicit therein based upon the statements of intention of combinations of separate disclosures such as at column 56 lines 14-25 therein. For example, antecedent basis for the projection disclosure is discussed in the next section herein.

The projection illumination amplifier disclosure of the present invention finds extensive antecedent basis in parent application Ser. No. 366,714 now U.S. Pat. No. 3,986,022. This antecedent basis will now be discussed to illustrate the relationship between the disclosure of the instant application and the disclosure of said parent application.

In said parent application, illumination amplifiers have been discussed for applications wherein projection is implicit therein. For example, use of an illumination amplifier in the disclosed camera system and photoplotter system establishes the projection nature of the illumination amplifier arrangement. Further, use of an illumination amplifier in combination with lenses further establishes the projection nature of the illumination amplifier arrangement. A detailed discussion of specific disclosures in said parent application providing antecedent basis with reference to U.S. Pat. No. 3,986,022 is provided below.

Control of projected illumination with an illumination amplifier finds antecedent basis in U.S. Pat. No. 3,986,022; particularly with reference to the photographic camera embodiments therein and implicit in the arrangements having lens arrangements therein. Camera systems are illustrated in FIGS. 8-10 therein and various lens arrangements are illustrated in FIGS. 6D, 9A, 9C, and 10 therein. Further, camera systems are discussed at column 41 line 46 to column 48 line 37 therein and lens arrangements are discussed at column 13 lines 33-49, column 31 lines 1-7 and lines 31-33, column 42 lines 35-39, column 45 line 61 to column 46 line 6, column 57 lines 19-37, and elsewhere therein.

The projection arrangement of the present invention is further shown in the discussions of FIGS. 8A-8C at column 42 line 1 to column 45 line 29 therein; wherein shutter and PG,129 aperture arrangements and rotation arrangements 800, 820, and 820C (FIGS. 8A, 8B, and 8C respectively) are disclosed in the preferred embodiment of a photoplotter system such as the photoplotter system referenced and incorporated by reference from U.S. Pat. No. 3,738,242 (U.S. Pat. No. 3,986,022 at column 1 lines 14-18 and lines 40-44; column 42 at lines 15-19; column 43 at lines 16-25 and elsewhere therein). Said U.S. Pat. No. 3,738,242 sets forth a projection-type illumination control system having illumination source 48; projection objects 68, 70, and 71; shutter 69; aperture 73; and rotation device 10. Substitution of the illumination amplifier aperture, shutter, and rotation devices of the present invention (as discussed relative to FIGS. 8A-8C in said U.S. Pat. No. 3,986,022) provides for illumination amplifier control and in particular liquid crystal control of projection illumination with the rotation control, aperture, and/or shutter of said U.S. Pat. No. 3,986,022. Further, terminology of transmitted illumination in said U.S. Pat. No. 3,986,022 such as at column 31 lines 41-43, column 46 lines 2-6, and elsewhere therein corresponds to the term projected illumination of the instant application.

Further, the use of coherent illumination such as from a laser source is disclosed in U.S. Pat. No. 3,986,022 at column 57 lines 4-9 for the various embodiments set forth therein and therefore can be used in various combination with the projection arrangement, as discussed herein.

Further, an audience display system is disclosed in U.S. Pat. No. 3,986,022 at FIG. 11 and at column 52 line 1 to column 55 line 27 therein, wherein it was stated therein as being intended that the various features in the disclosure that are set forth individually be combinable in various combinations such as at column 56 lines 14-47, column 57 lines 19-31, and elsewhere therein.

The projection feature of the photo-optical arrangement of said U.S. Pat. No. 3,738,242 is clearly established at column 1 lines 48-52 therein which states " . . . an optical arrangement required to project the image of the aperture onto the film . . . " [emphasis added]; clearly combining the aperture therein in a projection arrangement and wherein said aperture in the preferred embodiment of U.S. Pat. No. 3,986,022 is an illumination amplifier aperture in accordance with the projection illumination amplifier arragement of the present invention.

In view of the above, the projection illumination amplifier arrangement and the laser coherent light source features of the present invention find ample antecedent basis in parent U.S. Pat. No. 3,986,022.

Pulse modulated control can be implemented with the system of the present invention for various uses exemplified by machine control and illumination control; as discussed in the referenced patent applications, as is well known in the art, and as further discussed herein. Although pulse modulation may herein be exemplified with pulsed-width-modulation, it is herein intended that pulse-width-modulation be exemplary of other types of pulse modulation such as pulse-rate-modulation, pulse-code-modulation, and other types of pulse modulation.

A pulse modulation arrangement for use with a sound system such as a high fidelity and/or stereo type sound system will now be discussed with reference to FIG. 1A of U.S. Pat. No. 4,016,540. Data processor 112 can generate control signals such as whole number and discrete control signals 123 and 126 to interface electronics such as elements 120-122 and to device 124 which can be a pulse-width-modulated sound system. For example, machine 124 can be a sound transducer such as a speaker and electronic devices 120-122 can be pulse-width-modulated amplifiers and controls used in place of the pulse-width-modulated servos which are discussed in the referenced patent applications. Alternately, pulse modulated digital signals can be generated with data processor 112 such as with a discrete output signal which can be signal 101 to interface device 100. In an embodiment where signal 101 is a pulse modulated signal, element 102 can be a power amplifier to generate pulse modulated signal 103 as a power signal to drive transducer 104 to generate sound signal 105. Use of a data processor to generate a pulse modulated output signal such as with a discrete signal is discussed in referenced application Ser. No. 134,958 at page 22 line 2 to page 23 line 15 and elsewhere in the referenced patent applications. The above-described arrangement can be used for a sound response system such as discussed with references to interface 100 (FIG. 1A) which may be used for a toy, a game, or multitudes of other uses some of which are discussed in referenced U.S. Pat. No. 4,016,540. Further uses of this pulse modulation arrangement will now become obvious from the teachings herein.

Pulse-width-modulation has been discussed in detail in the referenced patent applications for a machine control embodiment and for an illumination control embodiment, wherein these disclosures have been incorporated herein by reference. For example, a pulse-width-modulated arrangment has been disclosed in referenced application Ser. No. 101,881 particularly with reference to FIGS. 1 and 16-19 therein; at page 33 lines 13-27, page 85 lines 23-25, page 86 lines 7-24, and page 88 lines 11-15; and elsewhere therein. Further, a pulse-width-modulation arrangement has been disclosed in referenced application Ser. No. 134,958 particularly at page 3 lines 21-28, page 6 lines 14-24, and page 22 line 2 to page 23 line 15, and elsewhere therein. Yet further, a pulse-width-modulated arrangement has been disclosed in referenced application Ser. No. 135,040 particularly at page 10 lines 10-15, page 18 lines 16-26, page 22 lines 1-28, page 24 lines 14-28, page 26 lines 10-16, page 31 line 4 to page 32 line 5, and elsewhere therein. Still further, a pulse-width-modulation arrangement has been disclosed in referenced application Ser. No. 246,867 particularly in FIGS. 4A and 4B; at page 24 lines 27-33 and page 27 line 1 to page 34 line 30; and elsewhere therein. Yet further, a pulse-width-modulated arrangement has been disclosed in referenced application Ser. No. 302,771 particularly with reference to FIGS. 5, 6, and 8; at page 21 line 30 to page 22 line 2 and page 57 line 1 to page 67 line 24; and elsewhere therein. Still further, a pulse-width-modulated arrangement has been disclosed in referenced applications Ser. No. 366,714; Ser. No. 727,3300; and Ser. No. 730,756 particularly with reference to FIGS. 2 and 6E and at page 16 lines 10-19, page 17 line 1 to page 21 line 15, page 46 lines 18-30, and page 48 lines 12-34; and elsewhere therein and further with reference to applications Ser. No. 727,330, and Ser. No. 730,756 particularly at page 172 lines 9-25 and elsewhere therein.

As an alternate embodiment to the D/A converter of the interface device, a pulse modulated or other duty cycle modulated arrangment can be used. Such a duty cycle arrangement provides particular advantages, where a duty cycle device may be a digital device which may be more compatible with the digital electronics of the digital audionic system than would be a hybrid D/A converter arrangement. Various pulse modulated devices such as pulse-width-modulated devices are set forth in the copending applications in the chain of related applications which are incorporated by reference such as for the pulse-width-modulated servo drives of referenced applications Ser. No. 101,881; Ser. No. 134,958; Ser. No. 135,040; Ser. No. 339,817 now U.S. Pat. No. 4,034,276; and Ser. No. 339,688 and for illumination control in referenced applications Ser. No. 366,714 now U.S. Pat. No. 3,986,022; Ser. No. 727,330; and Ser. No. 730,756 set forth a pulse-width-modulated arrangement in FIGS. 2B, 2C, and 2D therein. Further, various pulse-width-modulated drives are commercially available and may be used with the system of the present invention for output transducer drivers in place of the D/A converter arrangement discussed herein.

In one embodiment such as discussed herein with reference to FIG. 17, a pulse-width-modulated signal may be generated with a counter such as by loading the output digital number into the counter and permitting the counter to count-down to zero. When the counter counts-down to zero, detection of the counter zero condition or the counter overflow condition can be used to reset a flip-flop. The flip-flop can be set at the start of the new cycle. Therefore, the output of the flip-flop set at the beginning of a cycle and reset after a controlled period of time provides a pulse-width-modulated output signal to drive an output transducer. Alternately, the pulse-width-modulated signal can be generated under program control of the computer, where the computer can set the flip-flop at the beginning of a cycle and can provide a program time delay for resetting the flip-flop thereby performing the same function as the counter described above; such as discussed in greater detail in the related applications referenced herein.

Further, the pulse modulated servo arrangement of the referenced patent applications set forth interface register and counter arrangements for interfacing a computer to a servo. These arrangements are exemplary of interfacing a computer to a sound generation arrangement wherein servo electronics 120-122 of the referenced patent applications is exemplary of sound interface electronics and wherein machine 124 of the referenced patent applications is exemplary of a sound transducer such as a speaker.

The audionic system of U.S. Pat. No. 4,016,540 has been discussed in a preferred embodiment using a digital-to-analog converter 102 to interface between data processor 112 and transducer 104 (FIG. 1A). Alternately, other arrangements can be used including analog, hybrid, and digital arrangements as disclosed in U.S. Pat. No. 4,016,540 particularly at column 7 lines 15-24 and also at column 5 line 67 to column 6 line 19 and elsewhere therein. An analog embodiment is exemplified by the direct outputting of analog signals stored in an analog ROM or other analog memory as discussed in referenced application Ser. No. 812,285 such as at page 41 line 16 to page 42 line 7 and elsewhere therein. A hybrid (analog and digital) embodiment is characterized by the digital-to-analog converter arrangement discussed in U.S. Pat. No. 4,016,540 with reference to FIG. 3. A digital embodiment can be implemented as the pulse modulated embodiment discussed herein such as with reference to FIGS. 9A and 9B. Further, a digital embodiment is illustrated in the referenced applications such as applications Ser. No. 101,881; Ser. No. 134,958; Ser. No. 135,040; Ser. No. 302,771; etc. such as for controlling analog servos with pulse-width-modulated signals as discussed elsewhere herein wherein digital commands are loaded into counters and registers for controlling pulse-width-modulated servos. Many other embodiments will now become obvious to those skilled in the art from the teachings herein.

A time-domain pulse modulator will now be discussed for a preferred embodiment using the monolithic computer of the system of the present invention for generating a pulse-width-modulated signal under program control. Other pulse modulation arrangements will now become obvious from the teachings herein such as using program controlled arrangements as described herein and as described in related application Ser. No. 134,958 at page 22 line 2 to page 23 line 15; or using hardwired arrangements as disclosed in the related patent applications referenced herein; or using other computers, programs, and/or arrangements as will now become obvious from the teachings herein.

A program controlled pulse-width-modulation arrangement will now be discussed with reference to FIGS. 17A and 17B. An interface arrangement 971 consistent with the data processor of referenced application Ser. No. 101,881 is illustrated in FIG. 9A. A flow diagram 976 for generating a pulse-width-modulated signal with arrangment 971 (FIG. 17A) is illustrated in FIG. 17B. Arrangement 971 constitutes set-reset flip-flop 972 which is set by discrete output signal DO-8, reset by discrete output signal DO-9, and used to control device 974 with output signal 975 from flip-flop 972. Device 974 can be an audio speaker, a servo, or other device controlled with a pulse modulated signal. Amplifier 973 can be used to amplify output signal 975 to drive output device 974. Feedback signal DI-8 provides feedback on the state of flip-flop 972 to the data processor. The data processor generates signal DO-8 to set flip-flop 972 and generates signal DO-9 to reset flip-flop 972 under program control using discrete output instructions. A time delay between generating the DO-8 signal and the DO-9 signal controls the time period that output signal 975 is in the high state or the duty cycle of output signal 975. Therefore, the duty cycle of output signal 975 can be directly controlled by the data processor under program control. One form of program control which is exemplary of a wide range of methods is discussed herein with reference to FIG. 17B.

Flow diagram 976 (FIG. 17B) illustrates one method for generating pulse-width-modulated signal 975 under program control. The computer enters subroutine 976 through operation 977 and exits subroutine 976 through operation 983 with well-known subroutine operations. For example, ENTER operation 977 can include a calling sequence such as saving the return address to the main program or to the executive program and EXIT operation 983 can include fetching the stored return address and transferring back to the main program location defined with the return address, as is well known in the computer programming art.

After entering subroutine 976 through operation 977, the program initializes the subroutine such as by loading parameters or constants into various registers and memory locations. For example, a time delay word that defines the width of the pulse-width-modulated signal is defined as the N.sub.o parameter which is loaded into the N scratchpad register; wherein this scratchpad register designation is provided for convenience and may be assigned to any scratchpad register or other storage in the computer. The time delay number N.sub.o can be provided as a stored constant, or generated under program control, or generated by various known methods to determine the time delay between discrete output signals which determines the width of output pulse 975 and therefore the information content of the pulse-width-modulated signal.

The program generates the DO-8 signal with a discrete output instruction to set flip-flop 972 with operation 979 and then executes a time delay iterative routine using decrement operation 980 and test operation 981 to control the width of pulse-width-modulated output signal 975. The N-parameter is successively decremented in operation 980 to provide a time delay and tested with operation 981 to detect when the time delay has expired. Operations 980 and 981 can be implemented with a decrement and transfer on non-negative instruction, where the N-parameter in the N-register is decremented and the program operation transferred until the N-parameter is decremented to a negative number. The conditional transfer on the N-parameter being non-negative is shown by the looping back from the test operation 981 to the decrement operation 980 along the positive path. When the N-parameter has been decremented to a negative number, the conditional transfer is disabled and the program operations continue in sequence to operations 982 and 983.

Operation 982 discontinues the pulse-width-modulated output signal 975 by generating the DO-9 signal with a discrete output instruction to flip-flop 972. Program operation then continues to exit operation 983 to exit the subroutine.

The invention disclosed herein is presented in preferred embodiments of illumination control arrangements to exemplify the inventive features, but the scope of this invention is much broader than illustrated with these preferred embodiments. Therefore, the scope is intended to be broadly interpreted to cover the general fields of illumination control.

Various publications may be used for providing background for this invention and for illustrating the prior art. The various subject areas and associated references for each subject area are listed below.

(1) Integrated circuit technology is described in the book Integrated Circuits by Raymond M. Warner, Jr. and James N. Fordemwalt (Editors) for McGraw-Hill Book Company (1965).

(2) Digital computer technology is described in the books

(a) Digital Computer Design by Edward L. Braun for Academic Press (1963) and

(b) Digital Computer Design Fundamentals by Yaohan Chu for McGraw Hill (1962).

(3) Digital computer programming is described in the books

(a) Programming: An Introduction to Computer Languages and Techniques by Ward Douglas Maurer for Holden Day Inc. (1968),

(b) Programming for Digital Computers by Joachim Jeenel for McGraw Hill (1959), and

(c) Elements of Computer Programming by Swallow and Price for Holt, Rinehart, and Winston (1965).

(4) Analog computer technology is described in the book Methods for Solving Engineering Problems Using Analog Computers by Leon Levine for McGraw Hill (1964).

(5) Servo technology is described in the book Automatic Control Systems by Benjamin C. Kuo for Prentice-Hall (1962).

(6) Illumination technology is described in the books

(a) Optics, A Course For Engineers and Scientists by Charles Williams and Orville Becklund for John Wiley and Sons Inc.,

(b) Optical Data Processing by Arnold Roy Shulman for John Wiley and Sons Inc., and

(c) Optics by Bruno Rossi for Addison-Wesley (1957).

(7) Integrated circuits are described in the book The TTL Data Book For Design Engineers from Texas Instruments Incorporated.

(8) Thermal design is described in the articles

(a) What's New in Cool(ing)? by W. S. Hudspeth in the May 1977 issue of Electro-Optical Systems Design magazine at pages 32-37,

(b) A New Approach to High-Power Microstrip Attenuators by Jerry McNeal and Larry Gordon in the October 1977 issue of Electronic Packaging and Production magazine at pages 109 and 110, and

(c) Cold-Plate Thermal Design, Analysis and Sizing by Ira Leonard and Steven Axelband in the October 1977 issue of Electronic Packaging and Production magazine at pages 101-107.

Various elements of the present invention have been described herein separately for simplicity. In a preferred embodiment, various elements of the present invention may be used in combination to provide the combined advantages of the individual elements. These combinations will become obvious to those skilled in the art from the teachings of this invention. As an example the combination of the aperture size device 820 (FIG. 8B), aperture rotational device 800 (FIG. 8A), and shutter device 838 (FIG. 8D) can be provided by combinations of the patterns described for each independent arrangement.

Illumination processing arrangements may be shown to illustrate individual features and may not repeat description of other arrangements that are described herein or that will become obvious to those skilled in the art from the teachings of this invention. For example, aperture, shutter, and control arrangements are individually discussed in detail herein but may not be repeated for each specific description. It is intended that such aperture, shutter, and control arrangements be useable with other arrangements described herein such as the illumination computer. In general, it is intended that all individual features of this invention be useable in combination with all other individual features of this invention.

Inventive features that may be used in combination include open loop or closed loop excitation, digital or analog excitation, aperture and shutter devices, and other such features. Further, such combinations may not be individually distinguishable where, for example, the aperture and shutter devices may be integrated together by making all aperture segments 826-830 (FIG. 8B) reflective to provide shutter capability.

For the various embodiments discussed herein, the illumination amplifier may be an integral part of an illumination source such as a glass enclosure of a bulb, an intermediate device placed inbetween a source and a receiver, or other such arrangement.

Illumination is herein intended to be interpreted in broad form and is intended to mean generalized illumination including light, both visible and non-visible, electron beams, generalized electromagnetic radiation including microwaves, and other forms of illumination. Illumination is intended to further include natural light from the sun, generated light such as from a light bulb, coherent light such as from a laser, and non-visible light such as infra-red and ultra-violet illumination. Illumination may herein be referred to as illumination signals and illumination beams to describe directed illumination. Illumination may have a broad spectrum or a narrow spectrum. Well known illumination processing devices such as filters may be used to selectively provide illumination of a desired spectral characteristic. The term illumination as used herein may mean a particular characteristic of an illumination signal such as intensity, intensity of a particular spectral region, or other illumination characteristic.

An illumination source is herein intended to be interpreted in broad form and may include a single source or a plurality of sources, a light bulb source for visible light, a laser or maser source for coherent illumination, the sun as a source of natural sunlight, and other sources of illumination.

A preferred embodiment of an illumination amplifier is discussed herein as a variable transmissivity or reflectivity device such as the well known liquid crystal devices. Terms used herein such as illumination control device or illumination amplifier are intended to include such a variable transmissivity or reflectivity device, but is also intended to include other illumination control devices such as variable absorption and variable filtering devices.

Illumination processing devices are well known to those skilled in the art. Different types of illumination may require different types of processing devices. For example lenses, prisms, mirrors, filters, shutters, and apertures may be used for visible illumination; magnetic and electric fields may be used for electron beams; and other well known devices may be used for other types of illumination. These illumination processing devices perform functions such as collimating, focusing, blocking, shaping, and filtering illumination. Because these illumination processing devices and their use are well known, such devices may not be described herein unless necessary to further illustrate operation.

Illumination may be imaged, collimated, focused or otherwise processed with illumination processing devices. An image may be used to illuminate or to expose an illumination sensitive medium such as film for recording the image such as by exposing or otherwise affecting the medium.

An illumination amplifier such as a liquid crystal device that converts between reflective and transmissive characteristics can be provided in complement illumination arrangements. Complement illumination arrangements will be illustrated with reference to FIG. 3A, where source illumination is directed to illumination amplifier 300 which may be a liquid crystal amplifier. The transmissive characteristic of amplifier 300 permits transmitted illumination 302 to be transmitted through amplifier 300 to illumination receiver 303. The reflective characteristic of amplifier 300 permits reflected illumination 304 to be reflected from amplifier 300 to illumination receiver 305. Assuming conservation of illumination and constant input illumination 301, as the reflectivity of 300 is increased, the transmissivity is decreased, and conversely. Therefore as transmitted illumination 302 is increased, reflected illumination is decreased, and conversely. A complement arrangement can be illustrated with a simple example, where it is desired to first fully illuminate, then to remove illumination from an illumination receiver. For this example, the receiver can be arranged as receiver 303, where amplifier 300 can be made transmissive for illuminating receiver 303 and then be made reflective for removing illumination from receiver 303. In a complement arrangement, the receiver can be arranged as receiver 305, where amplifier 300 can be made reflective for illuminating receiver 305 and then can be made transmissive for removing illumination from receiver 305. Because of the complementing characteristics of reflective-transmissive illumination amplifier devices, it will now become obvious that either of the complement arrangements may be used for implementing an illumination amplifier arrangement. For simplicity, only one of the complement forms is usually described herein. It is herein intended that either of the complement illumination amplifier forms be useable with an embodiment, even though an embodiment may only be described relative to one of such complement forms.

The features of the present invention have been described for the preferred embodiment of an IAD, but these features may be applied to other illumination systems. For example, the pulse modulation arrangement can be applied to light emitting diode (LED) displays and to plasma displays to provide shades of intensity as discussed herein for the IAD embodiment. Further, the flat-plane IAD embodiment disclosed herein such as with reference to FIG. 6 can be used in conjunction with LED and plasma display devices.

Many features of the present invention are related to the machine control parent applications referenced herein. For example, a camera may be considered to be a machine and a photoplotter clearly bridges the technologies between a conventional photographic camera and a machine. Control of illumination and control of a machine, particularly with the microcomputer of the present invention and with other control arrangements are disclosed in detail in the chain of copending applications. Therefore, control of illumination and control of machines finds extensive basis in the instant application and in the chain of copending applications.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desireable, but which obviously is susceptible to modification in its form, method, mechanization, operation, detailed construction and arrangement of parts without departing from the principles involved or sacrificing any of its advantages.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means, method, and construction herein disclosed comprise the preferred form of several modes of putting the invention into effect, and the invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims .