Microfiche Reader

This invention relates to microfiche readers, and more particularly to an improved reader employing two lenses of different powers simultaneously substitutable one for the other in the projection light beam together with various auxiliaries including means for automatically varying the light beam intensity to maintain the lighting on the projection surface uniform.

Many proposals have been made heretofore designed to project an enlarged film image onto a viewing surface and dividable generally into a first category for displaying images from strip film, and a second category for displaying images from a microfiche. The latter category presents far more difficult problems because of the substantially greater magnification required and, in consequence, very substantially higher precision equipment to provide a well illuminated high resolution image. Microfiche images are mounted in side by side relation on a library size card which is typically sandwiched between a pair of plates mounted on an S-Y type fiche transport. This transport is supported in a horizontal plane for movement in both directions crosswise of the optical axis. The projection lens must be firmly supported normal to the plane of the fiche. Desirably, the focal plane of this lens should be maintained precisely spaced parallel to the plane of the fiche within a tolerance of one mil, as the fiche is moved to align any fiche with the optical axis. These requirements are substantially more stringent than for strip film readers. The lens should not change position axially or laterally of the optical axis during adjustment of the fiche transport and, desirably, suitable means should be provided for changing the magnification of the image on the screen as well as means for maintaining the lighting intensity of the projected image constant as well as means for presenting the projected image in a convenient reading position whether arranged crosswise or longitudinally of the fiche card.

Prior film readers embody some but not all of these features. The 1949 British Pat. No. 616,874 discloses a reader having means supporting a film strip on a turn table but the reader lacks various other desirable features and capabilities.

Designers have proposed film readers employing projection lenses of different powers for both microfiche and film strips. Constructions of this type are shown in U.S. Pats. to Strauss No. 2,630,739, Ikezu No. 3,588,226, Bolgar No. 3,888,576, Feifer No. 3,792,226, and Peters No. 3,369,450. A reader of this type is also being marketed by Washington Scientific Industries, Inc., Long Lake, Minnesota. These various constructions employ a variety of mechanisms for substituting one lens for another of a different power. Strauss mounts his two lenses on a rotary turret head but lacks satisfactory and reliable means for maintaining the focal plane of either lens at the requisite precise distance from film supported in an X-Y film transport. In fact, such a transport is not even suggested by this patentee. Peters U.S. Pat. No. 3,369,450 had but a single stationary projection lens the power of which he endeavors to change by interposing an additional lens component. Ikezu U.S. Pat. No. 3,588,226 discloses a pair of projection lenses of different powers so designed that the focal plane of each is located at the same axial distance from the film image but he fails to show any means for supporting the two lens units and for substituting one lens for the other relative to an X-Y fiche transport. Feifer U.S. Pat. No. 3,792,923 proposes a reader having a pair of different power lenses rigidly supported on a bracket arm movable about the same vertical axis and shiftable to bring one into operating position relative to one fiche transport and the other into proper operating position relative to a second fiche transport. Neither lens can be used selectively with the same fiche transport. Bolgar U.S. Pat. No. 3,888,576 employs a pair of immovably supported lenses of different powers in combination with a linkage mechanism for adjusting a reflecting mirror system to modify the size of the displayed image.

Various expedients have also been proposed heretofore to maintain the projecting lens of a microfiche reader precisely spaced from and accurately normal to an X-Y fiche transport mechanism. Spring biasing means for maintaining a projection lens against the transport are proposed by Peters U.S. Pat. No. 3,634,005; Schutrum et al. U.S. Pat. No. 3,717,400; Peters U.S. Pat. No. 3,807,845 and Akajama U.S. Pat. No. 3,565,513. Two other patentees namely, Brownscombe U.S. Pat. No. 3,815,975 and Graef U.S. Pat. No. 3,860,333, propose accomplishing this same objective in reliance on gravity to hold the lens directly against the cover of an X-Y transport. In each instance only a single projecting lens is provided in both the gravity-actuated and the spring biased constructions. The Washington Scientific reader also utilizes gravity to support a pair of lenses of different powers on a fiche transport. However, the mechanism employed for this purpose utilizes a slider for the two lenses in combination with a T-shaped slot. The vertical T-stem of this slot is located in the plane of the optical axis and requires that the lens in use be manually lifted to the top of the T-stem portion of the slot following which the slider is shifted horizontally along the T-head portion of the slot to bring the second lens into alignment with the optical axis at which time the second lens must be manually lowered onto the film transport. This construction requires skillful manipulation to avoid risk of serious injury to the two lens components as well as to the glass plates of the fiche transport, and equally important, that the operator must manipulate the lens in a particular manner else it is impossible to substitute one for the other.

This invention provides a microfiche reader avoiding the shortcomings and disadvantages of these various prior readers and is characterized by its simplicity, ease of operation and the high fidelity of the projected image in both its normal and in its more magnified scale. The two projection lenses of different powers are quickly shiftable into and out of alignment with the optical axis and each is held firmly captive in floating position on a precision X-Y fiche transport. Short linear movement of the lens support automatically lowers one lens into floating support on the transport as the other lens is elevated to its retracted position. At the same time the intensity of the light beam is automatically adjusted to provide the same lighting intensity on the viewing surface for both lenses. Additionally, magnetic stop means operate to hold the lens in use firmly in projecting position despite both planar and rotary movement of the fiche transport. Rotary movement of the fiche transport through 360.degree. is achieved by mounting the transport on a turntable having its axis aligned with the optical axis.

A pair of selectively usable projection lenses, the operating support therefor, together with the stops and automatic light intensity controls are housed within a unitary assembly readily removable by the novice for servicing or the substitution of another assembly.

It is therefore a primary object of the present invention to provide a unique and improved microfiche reader.

Another object of the invention is the provision of a microfiche reader having unique means for simultaneously and selectively shifting a pair of lenses of different powers into and out of alignment with the optical axis.

Another object of the invention is the provision of a microfiche reader for simultaneously elevating one lens while lowering a second into image projecting alignment with the optical axis of the reader.

Another object of the invention is the provision of a microfiche reader employing a pair of lenses of different powers selectively positionable in alignment with the optical axis while floatingly supported on the fiche transport together with means for holding that lens firmly in position while adjusting the fiche transport.

Another object of the invention is the provision of a microfiche reader utilizing a pair of lenses of different powers selectively shiftable into and out of alignment with the optical axis and including means for automatically maintaining the intensity of the projected image uniform irrespective of which lens is in use.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of the invention is illustrated:

FIG. 1 is a side elevational view of one preferred embodiment of the invention with portions broken away to show details of the cooling air passageway for the projection lamp;

FIG. 2 is a cross-sectional view on an enlarged scale taken along line 2--2 on FIG. 1;

FIG. 3 is a fragmentary view taken along line 3--3 on FIG. 2;

FIG. 4 is a transverse sectional view taken along line 4--4 on FIG. 2; and

FIG. 5 is a fragmentary top plan view of the turn table and fiche transport taken generally along line 5--5 on FIG. 2.

Referring initially more particularly to FIG. 1, there is shown a preferred embodiment of the invention microfiche reader, designated generally 10, mounted in a cabinet 11 enclosed except along its front face 12. The projection lamp 13 is mounted in a housing 14 beneath a horizontal counter or shelf 15 of cabinet 11 at a convenient reading height. The light beam from this lamp is directed upwardly through a projecting lens, in a manner to be described presently onto a downwardly facing mirror 17 mounted beneath the top of the cabinet in position to direct the light beam along the path indicated at 18 onto a forwardly inclined image viewing surface 19. This viewing surface is at a convenient viewing level for a seated viewer positioned in front of the open side 12 of the cabinet. A cooling air fan having an intake indicated at 20 directs cooling air through the housing 21, over the lamp 13, and thence downwardly and rearwardly through the air outlet passage 22.

As is best shown in FIGS. 2, 4 and 5, the central portion of the cabinet counter 15 is provided with a large circular opening 24 in which is mounted a turn table 25. The central portion of turn table 25 likewise is formed with a large opening 26 closed except for a central aperture by a plate 27 suitably secured to the underside of the turn table.

Fixed to the underside of plate 27 is a precision ball bearing 28 the outer raceway of which is fixed to a supporting bracket plate 29 firmly clamped at its corners by fasteners 30 (FIG. 4) to the underside of counter 15. Plate 27 and bracket 29 are provided with central openings 32, 33 (FIG. 2) which are in alignment with the vertical portion 34 of the optical axis. A condensing lens 35 is secured to plate 27 in alignment with this optical axis.

An X-Y fiche transport of any suitable construction well known in this art is secured to the upper side of plate 27 and is movable transversely of the optical axis to position any image of a fiche mounted therein in the light beam from lamp 13 directed upwardly therethrough by a mirror 38 (FIG. 2). This mirror is secured to an upwardly inclined end of housing 14. Fiche transport 36 has a lower set of precision trackways 42,42 (FIG. 4) extending lengthwise of counter 15 and a second set of precision upper trackways 43,43 (FIG. 5) extending crosswise of this counter. The upper set supports a rectangular frame-like carriage 44 and the lower set 43 supports a similar rectangular frame-like carriage 45 (FIG. 2). From the foregoing it will be understood that carriage 45 is movable to and fro crosswise of the counter whereas the upper carriage 44 is confined to similar movement lengthwise of the counter.

Referring to FIGS. 2 and 4 it is pointed out that a microfiche 47 is held flat and sandwiched between a lower transparent plate 48 and an upper transparent plate 49. Plate 48 is secured to carriage 44 by rabbeted keeper strips 50,50 (FIG. 2) whereas upper plate 49 can be pivoted upwardly about suitable stops extending along its rear longitudinal edge 51 (FIG. 5). This operation is facilitated by a finger tab 52 (FIG. 4) extending along and secured to the front edge of plate 49. Tilting the upper plate upwardly permits a fiche 47 to be inserted or removed from between the plates.

A unitary lens assembly housing, designated generally 55, has an elongated sheet metal housing 56 bridging turn table 25 and supported on legs 57 secured to counter 15 by screws 58. These screws are removable by inserting a wrenching tool downwardly through openings 59.

A pair of precision projection lenses 60,61 of different magnifying powers, as 24X and 60X, are slidably supported lengthwise of housing 56 for movement into and out of alignment with the optical axis 34 of the reader. The top wall of housing 56 is provided with a long rectangular opening supporting a slider for shifting the two lenses. The slider assembly comprises a pair of plates 62,63 secured together in spaced apart relation by fasteners 64 (FIG. 3) with the two plates in loose sliding engagement with the inner and outer surfaces of the top of housing 56. Knobs 65,65 secured to the opposite ends of the outer plate 63 (FIG. 2) provide convenient means enabling the operator to shift the lens slider plate 62,63 lengthwise of housing 55. The two lens assemblies 60,61 extend loosely through openings 66 in the two slider plates in order that the lens shifted into alignment with optical axis 34 is supported solely by the top plate of the fiche transport.

The means cooperating with slider plates 62,63 to move the lens units 60,61 vertically as they are shifted laterally will now be described. For this purpose upwardly converging ramps or camways 69 (FIGS. 2, 3, 4) are firmly secured to either interior sidewall of housing 56. Cooperating with these camways are pairs of pins 69 fixed to and projecting outwardly from the diametrical opposite sides of each of the lens units 60,61. These pins overlie the camways and ride upwardly or downwardly therealong as the slider is shifted lengthwise of housing 56. Cooperating with each of pins 69 are a pair of pins 70,70 having their upper ends fixed to the lower slider plate 62 and arranged closely adjacent the opposite sides of pin 69. As is made clear from FIG. 2, pins 69 are so arranged relative to the camways 68 that the lens units can be freely and floatingly supported by gravity on upper plate 49 of the fiche transport when either lens is in alignment with the optical axis 34. However, if the slider is shifted to lower the other lens unit, pins 69 of the lowermost lens will engage one pair of camways after a slight movement of the slider thereby to start elevating the lower lens as the other lens moves downwardly toward the fiche transport.

It is important that the lens in use be held firmly against movement while the fiche transport is being shifted to a different position. This is accomplished by permanent magnet means 72 one of which is secured to each of the opposite ends of the inner or lower slider plate 62 as shown in FIGS. 2 and 3. These permanent magnets are adjustably secured to plate 62 and abut a stop 73 of magnetic material fixed to housing 56.

Projection lamp 13 is de-energized while the slider is being moved to bring a different one of the lenses into operating position. However, once the lens approaches a floating position on the fiche transport one of the permanent magnets 72 engages the operating button 74 of a microswitch 75 mounted at each end of the slider path of travel. The microswitches 75 are connected in circuit with a rheostat 76 having its control knob mounted at one end of housing 56 as shown in FIG. 2 and this circuit also includes a fixed resistor connected in circuit with that one of the microswitches 75 controlling the current to lamp 13 when the lower powered one of lens 60,61 is in operating position. This resistor, not shown, is not in circuit with the lamp when the higher powered lens is positioned in the optical axis. The value of the resistor is chosen to provide the same lighting intensity on the viewing screen 19 when the low power lens is in use as when the high power lens is in use. If the user wishes to adjust this uniform light intensity he merely adjusts the control knob of rheostat 76.

It is pointed out that all electrical components within the lens assembly 55 are connected to a female socket 79 mounted in the wall of housing 56. A male connector 80 (FIG. 4) can be quickly disconnected from socket 79 when assembly 55 is removed for inspection or servicing.

The two lens units 60,61 are similar to one another and will be described by reference to FIG. 4. These units include the optical lens assembly proper 82 which is externally threaded to mate with the threads of a support tube 83. The knurled upper end of assembly 82 can be adjusted axially of tube 83 to locate the focal plane of the magnifying lenses precisely at the proper focal distance from fiche 47 when the lens unit 61 is floatingly supported on upper plate 49 of the fiche transport. In this connection it is pointed out that the lower end of tube 83 is beveled to provide a very narrow circular edge 84 which rests flush against the upper surface of plate 49. This edge must be precisely finished to support the lens components in accurate alignment with the optical axis 34.

The operation of the microfiche reader will be apparent from the foregoing detailed description of its components. A fiche 47 is preferably placed beneath the upper plate 49 of the fiche transport while the slider for the two lenses is in an intermediate position to support lenses 60,61 partially elevated along camways 68,68. This permits the operator to lift the upper plate about its rear edge without interference while the fiche is being inserted. After insertion of the fiche the operator then uses the slider control knobs 65 to bring the lens of the desired power into alignment with the optical axis. When the selected lens is floatingly supported on the upper plate, one or the other of the permanent magnets 72 will be engaged with the magnetic stop 73 to hold the slider firmly in place while at the same time maintaining microswitch 75 closed to energize lamp 13 at the appropriate intensity for the lens then resting on the fiche transport.

The reader is now in readiness for use and the operator may project any image of the fiche on the viewing screen simply by utilizing one or the other of the transport control knobs 67 (FIG. 5) to bring the desired image into alignment with the lens in use. If this image has its material arranged lengthwise of the page rather than crosswise, the operator uses the turn table control knob 23 to rotate the turn table 90.degree. in the proper direction. If the user wishes to change the otherwise uniform lighting intensity, he merely operates the rheostat control knob 76.

If the user wishes to view the projected material in a differently magnified scale he merely moves the slider to its alternate position to place the other of the projection lenses in alignment with the optical axis. When in this position the associated one of magnets 72 will lock the slider in its alternate position and at the same time will operate the associated switch 75 to change the light intensity so that the lighting intensity on the viewing screen remains at the same value as when the other lens was in use. It is therefore clear that no action on the user's part is required other than to use one of the control knobs 67 to shift the lens slider to its new position.

While the particular microfiche reader herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims.