Optical Fibers

U.S. Pat. No. 3,431,410

U.S. Pat. No. 4,035,215

U.S. Pat. No. 4,097,917

The ability of optical fibers to transmit light substantially as pin points is, of course, well known and has been utilized to advantage in many different ways among which are display devices where light applied to corresponding bundled ends of fibers is displayed at their other ends in an attractive manner.

Of such display devices, U.S. Pat. No. 3,431,410 disclosed the use of optical fibers having their bundled ends disposed with a rotating color wheel interposed between them and a light source with their free ends falling over the upper end of a holder.

The display device of U.S. Pat. No. 4,035, 215 included three assemblies of optical fibers each of which has fixed bundled ends with their other ends free and disposed as sprays movable in response to fan created air currents. The intensity of the light produced by the lamp operatively associated with the bundled ends of each assembly varied with variations in an associated stereo output.

In yet another display device, see U.S. Pat. No. 4,097,917, the bundled ends of optical fibers were rotated as a unit with the other ends of the fibers free to respond to rotative forces to provide lines of light varying with the speed at which the bundle was rotated.

The general objective of the present invention is to provide display devices in which the lit ends of optical fibers appear as pin points of light moving in space, desirably, but not necessarily, with other lit ends stationary.

In accordance with the invention this objective is attained with a box divided by a partition into front and rear sections with the front of a box a one way window with its interior surface functioning as a mirror. Optical fibers extend forwardly through the partition in a predetermined spaced apart, parallel relationship with their ends in the rear section held as a bundle against which light, desirably of constantly changing color is directed.

The optical fibers are so dimensioned in relation to their length that their free ends are resilient and have normal positions at right angles to the window. Means are provided momentarily to displace at least some of the fibers so that when the box is viewed from the front, their lit ends appear as points of light moving in space. It is preferred that some of the free fiber ends are stationary and it is preferred that the opacity of the window be such that only the lit ends of the fibers be visible to the viewer.

An important objective of the invention is to enable the effect of a large number of pin points of light to be attained with relatively few fibers. This objective is achieved by having the partition a mirror facing the front of the box so that light is reflected between it and the rear surface of the window and reflected through the front of the box as fibers are displaced and return to their normal positions.

Another objective of the invention is to effect the displacement and return of free ends of fibers in a wanted manner. For this purpose, a shaft driven by a motor in the rear section of the box, where the shaft has a color wheel or disc, extends through the partition into the front section where it carries at least one cam. Free fiber ends that are to be displaced thereby are arranged as a concentric set in the path of lobes of the cam.

A further objective of the invention is to have pin points of light that may be made to move both in a regular manner and in an erratic manner. To that end, the shaft is provided with a second cam in the front section. The paths of the lobes of the two cams are concentric with the one cam whose lobes have the longer radius ahead of the other cam. Fiber ends to be displaced by the smaller cam are arranged as a concentric set in the path of the lobes of that cam with the larger cam translucent to enable the lit ends of the second named set to be observed. It is preferred that an inner one way window be located between the front window and the mirror with its rear surface functioning as a mirror.

Other objectives, novel features and advantages of the present invention will be apparent from the accompanying drawings, the specification and the appended claims.

The accompanying drawings illustrate a preferred embodiment of the invention of which -

FIG. 1 is a partly sectioned side view of a light display device in accordance with the invention;

FIG. 2 is a section, on a substantial reduction in scale, taken approximately along the indicated line 2--2 of FIG. 1;

FIG. 3 is an exploded view of the device;

and

FIG. 4 is a somewhat schematic and much simplified view illustrating the functioning of the components of the device.

The light display device illustrated by the drawings has an open ended box or housing, generally indicated at 5 which is shown as consisting of a bottom 5A in the form of a channel that is rectangular in cross section and a cover 5B. The bottom 5A and the cover 5B are provided with vertically aligned slots of channels 6, 7, and 8.

The slots 6 receive and hold a window 9 of the one way type which closes the front of the box 5 and a sheet, either glass or plastic, and disposed so that its rear surface functions as a mirror. The slots 7 receive and support a like one way window 10 so disposed that the rear surface functions as a mirror while the sots 8 receive and support a mirror 11 facing the front of the box. The mirror 11 is a partition dividing the box 5 into front and rear sections.

The other or rear end of the box is closed by a plate 12 to the interior of which is secured a motor 13 and a lamp 14. The plate 12 has a port 15 through which a cord 16 extends with its leads 16A and 16B at one end connected to the corresponding leads of the motor and lamp and with the other lead ends connected to a plug 17.

The shaft 18 of the motor 13 extends freely through the one way mirror 11 and the one way sheet 10 between which there is a first or front cam 19 and a second or rear cam 20 both of which are of transparent material and are fast on the shaft 18 with a spacer 21 between them. The two cams differ both in size and shape and in function. The lobes 20A of the cam 20 are shown as arcuate and four in number and uniform in shape and in radial extent. The lobes of the cam 19 are shown as seven in number and as uniform in radial extent. As each varies in size and shape from any other, the lobes are designated 19A, 19B, 19C, 19D, 19E, 19F, and 19G and their path is outside the path of the lobes 20A.

The motor shaft 18 also carries a wheel or disc 22 having sections, see FIG. 3, of different colors. The color wheel is located between the lamp 14 and a holder 23 which is provided with a lens 24 and is held by a bracket 25 shown as attached to the rear of the mirror 11. The holder 23 unites as a bundle corresponding ends of a substantial number of optical fibers including a first inner circular series of fibers 26 concentric with the shaft 18, a second, outer concentric series of fibers 27 and a third series of fibers 28. The fibers of each series extend through the mirror 11 and are held thereby parallel to the shaft 18 and the fibers of each series are of a diameter appropriate for their length to provide free ends in the front section of the box 5 that are resilient and have normal positions at right angles to the window 9.

The optical fibers 26 are disposed with their free ends in the path of the lobes 20A of the cam 20 and terminating short of the one way window 10 while the free ends of the fibers 27 are outside the path of the lobes of the cam 20 and extend forwardly in the path of the lobes of the cam 19 through radial slots 29 in the window 10 and terminate short of the front window 9. The inner end of each slot 29 accommodate the associated fiber 27 when unflexed while its outer slot end limits the extent to which the fibers 27 can be displaced.

In operation, with the color disc 22 and the cams 19 and 20 rotating together, the free ends of the fibers 26 are displaced by the lobes of the cam 20 along substantially regular paths determined by the cam lobes 20A while the free ends of the fibers 27 confined within the slots 29 of the window 10 are displaced radially for a distance and interval determined by the size and shape of the lobes of the cam 19 each of which is shown as differing from the others.

While the free ends of the fibers 27 are confined in the slots 29 so that the extent of their travel under the influence of the lobes of the cam 19 is limited, the lobes are so formed as to affect their movement in both directions in their slots in various ways as determined by the leading and trailing edges of each lobe and the junction between the trailing edge of each cam lobe and the leading edge of the next adjacent cam lobe.

While, in the disclosed embodiment and, as is preferred, each lobe of the cam 19 differs from the others, all the differences between the seven cam lobes wll not be detailed. By way of example, however, the cam lobes 19A and 19E may be compared to illustrate how different rates of filament travel are effected by their respective leading and trailing surfaces. In the case of the cam lobe 19E, the leading and trailing edges are substantially identical. In the case of the cam lobe 19A, its leading edge is similar to but shorter than the leading edge of the cam lobe 19E and its trailing edge is such that the optical fiber 27 engaged by that lobe is free to return by its inherent resiliency to the inner end of the slot 29 by which it is confined. Thus the leading and trailing edgs of each cam lobe control the rate of travel of the filaments 27 which they successively engage and the rate of travel controlled by each edge may be varied. Note that both the leading and trailing edges of the cam lobe 19B provide a substantially uniform rate of travel of a fiber end 27 that is faster than that effected by the corresponding surfaces of the cam lobe 19E.

It should also be noted that while the trailing edge of the lobe 19G and the leading edge of the lobe 19H so merge that the fiber end 27 between them travels substantially continuously, the junction of said edges being spaced radially with respect to the shaft axis to have a circular path just inside the normal positions of the fibers 27. In the disclosed embodiment of the invention, the other merging leading and trailing edges of adjacent lobes define dwells enabling the fiber end or ends 27 between them to be at rest for intervals that vary.

The consequences of the action of the cams 19 and 20 are schematically illustrated in FIG. 4. When any of the fiber ends is disposed normal to the mirrors, light is transmitted directly through the one way sheet or sheets in front of it. When, however, the free ends of the fibers 26 are deflected by the lobes 20A, light is also reflected by the rear surfaces of the windows 9 and 10 with the reflected light also again reflected by the mirror 11. In the case of the fiber ends 27, light therefrom is transmitted directly through the window 9 until those fiber ends are reflected radially by the lobes of the cam 19, light then being both reflected and transmitted by the window 10 and the reflected light again reflected by the mirrors 11. In FIG. 4, the reflected light ray patterns are greatly simplified as it will be appreciated that the extent of the reflection is substantially infinite so that only primary paths of the reflected rays is indicated.

In the disclosed embodiment, there are eight optical fibers 26, sixteen optical fibers 27, and sixteen optical fibers 28 but due to the use of reflective surfaces, the effect is that of myriad moving pin points of light.

It will be appreciated that, when the box is viewed from in front, only the lit ends of the fibers are visible as in practice and as is preferred, the opacity of at least the front window 9 is such as to make the fibers invisible so that a shadow box effect is created. The positions of the lit fiber ends 28 are constant and the lit fiber ends 26 constantly move in a substantially regular manner while the lit fiber ends 27 travel erratically with all lit ends appearing as pin points of light in space of constantly changing color.