WO1997024645A1

WO1997024645A1 - Optical switching component

Info

Publication number: WO1997024645A1
Application number: PCT/SE1996/001686
Authority: WO
Inventors: Wlodek Holender
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1995-12-29
Filing date: 1996-12-17
Publication date: 1997-07-10
Also published as: AU1402897A

Abstract

A general optical display and switching system and method is disclosed. The system comprises a plurality of stacked kinoforms (Fig 3) and control means (310) for selectively activating one or more kinoforms. Each kinoforms (301-305) comprises a preformed transparent quasi-planar structure that can diffract light and optionally permit the projection of an image. The interstices in the structure are filled with liquid crystal (404, 414, 504, 508). Means (440, 540) are provided to activate the liquid crystal by applying an electrical field along an axis perpendicular to the plane of the quasi-planar structure. The liquid crystal is selected so that its index of refraction in the inactive state is approximately equal to the index of refraction of the transparent structure. The liquid crystal material is further selected so that when it is activated by the application of an electrical field, it has an index of refraction that is substantially different from that of the transparent structure. By selective activation of one of a plurality of kinoforms, a specific image can be projected on a screen (Fig. 3). The system and method disclosed can also be used as an optical data storage and retrieval device (Fig. 6) or as a high-speed optical switch (Fig. 7).

Description

OPTICAL SWITCHING COMPONENT

DESCRIPTION

1. Technical Field of the Invention The invention relates to optical switching and, more particularly, to a high-speed image selection and switching system employing liquid crystal devices and optical holograms.

2. Description of Related Art

In recent years optical devices have assumed increasing importance in electronics and telecommunications systems. For example, as the need for information handling of increased bandwidth has risen, fiber-optic transmission systems have been developed to fill this need. In addition, optical and electro-optical switching systems are capable of operating at much higher speeds than conventional electronic and semiconductor switching devices. Optical information processing and display devices have also assumed an important role in electronic technologies. Devices such as flat liquid crystal display

(LCD) panels hold a great deal of promise in addressing the need for larger optical display devices in applications such as video conferencing, advertising, and similar uses. Liquid crystal display apparatuses offer a large number of advantages such as light weight and thin structural profile.

Such devices have conventionally used twisted nematic (TN) liquid crystal panels employing a rotary polarization characteristic of the liquid crystal. A conventional TN liquid crystal panel uses two polarizers, one on the incident side and the other on the exit side. Incident light passes through an incident side polarizer and becomes uni-directionally polarized and then enters a liquid crystal panel.. When the liquid crystal is in the inactive condition (the "off" condition) , it causes the polarization of the (unidirectionally-polarized) incident light to be rotated by 90 degrees upon passage through the liquid crystal layer. Conversely, when the liquid crystal is in the activated state (the "on" condition) , the unidirectionally-polarized incident light is transmitted through the liquid crystal layer with no rotation of the polarization.

As a result of this rotary polarization characteristic of TN liquid crystal, if the polarizers on the incident side and the exit side are orthogonal in the direction of their polarization, then incident light will be transmitted through the panel whenever it is in the off condition, and conversely, incident light will be blocked from passing through the panel whenever the liquid crystal is in the on condition. However, if the polarization directions of the incident-side and exit-side polarizers are made parallel to each other, the inverse phenomenon can be obtained. In this manner, a conventional liquid crystal display panel can be used to modulate light to display an image.

Other techniques for displaying images include the use of holograms. There are at least two types of holograms known in the art. Cognoscenti can distinguish between "thin" holograms and "volume" (phase) holograms. The advantages and disadvantages of these two types of hologra s are recited in U.S. Patent No. 4,850,682 entitled "Diffraction Grating Structures" issued to H. J. Gerritsen.

"Thin" holograms tend to accept and respond to incoming radiation over a relatively wide range of incidence angles. However, as the angle of incidence changes, the direction of the output radiation changes markedly with "thin" holograms. In contrast, "volume" holograms tend to diffract incident incoming radiation so that it remains within relatively limited confines.

"Thin" holograms do not have as high an efficiency as

"volume" holograms, and a considerable fraction

(typically, of the order of 50%) of the incident light passes through a "thin" hologram without diffraction. Although "volume" holograms are more efficient, they respond to incoming radiation only over a relatively narrow range of incidence angles.

Combinations of liquid crystal devices and holographic apparatuses are also known in the art. For example, U.S. Patent No. 5,198,912 entitled "Volume Phase Hologram with Liquid Crystal in Microvoids Between Fringes" issued to R. T. Ingwall et al. discloses a volume phase hologram with liquid crystal contained in microvoids between the interference fringes. Similarly, it is known to construct an electrically switchable hologram employing a phase hologram and a liquid crystal layer. The optical influence of the holographic layer over incident light is controlled by varying an electrical field that is applied to the liquid crystal layer. Such a device is disclosed in the article entitled "Electrically Switchable Holograms for Image Processing Using Liquid Crystals" by M. Stalder and P. Ehbets, Proceedings of the Fourth International Conference on Holographic Systems, Components and Applications, Neuchatel, Switzerland, IEE Publication No. 379, pp. 210- 215 (September 1993) .

Although twisted nematic liquid crystal holographic image devices are known, no prior art is known to exist which incorporates these devices into a high-speed image selection and optical switching system wherein different layers of such materials are stacked and the layers are selectively energized to choose one of a plurality ^■of encoded images which in turn is used to influence the passage of incident light through the stacked structure.

SUMMARY OF THE INVENTION

The system of the present invention includes a stacked or sandwiched electro-optical device comprising a plurality of optical devices, referred to hereinafter as kinoforms.

One type of kinoform described in the art comprises a diffraction device that can bend or deflect coherent light to precisely form an arbitrary but invariant spatial pattern. See Anders Wallerius, Sverkers Skarpta Laser

Prickar Rάtt [Sverker' ε Enhanced Laser Aims Dots

Precisely], 1994:36 NY TECHNIK 1, 22-25 (Stockholm, Sweden Sep 8, 1994) (in Swedish) . In general, each kinoform includes a surface capable of generating a hologram or of reflecting or diffracting light. For ease of reference, this surface will be referred to in this application as a hologram-generating surface. However, it should be understood that, in general, this surface can be a light reflecting or diffracting surface and not just a surface capable of generating a hologram.

The hologram-generating surface is in turn covered by a liquid crystal layer that can be selectively activated to optically enhance or negate the light- transformative effect of the hologram-generating surface. Selective activation of one of the plurality of kinoforms results in the interaction of the incident light with the hologram-generating surface in that kinoform while the other (inactive) kinoforms are simultaneously rendered transparent to the incident light beam. This technique enables the rapid selection with random access of various incident-light-modifying holographic image patterns and produces a high-speed optical switching and display system.

In one aspect the present invention includes a system and method for selectively projecting encoded images stored on a plurality of kinoforms in which an encoded image is stored on a kinoform by forming an encoded image on a transparent first material having a first index of refraction. The voids in the formed transparent first material are filled with liquid crystalline material having a second index of refraction when activated by an electrical field and a third index of refraction when no electrical field is applied. The third index of refraction is approximately equal to the first index of refraction and is different from the second index of refraction.

First and second transparent conductive films are deposited adjacent to the formed transparent first material to act as electrodes for applying an electrical field to the liquid crystal and are arranged on substantially parallel planes on opposite sides of the formed transparent first material. All the kinoforms containing stored encoded images are aligned into a stack. An image stored on a particular kinoform is selected by activating the liquid crystalline material on the kinoform using an electrical field. The selected image is illuminated with coherent light and projected in viewable form. In another aspect the present invention includes a system and method for data storage and retrieval in which encoded data sequences are stored on a kinoform and indexed to permit identification of specific data sequences. The kinoform on which a specific data sequence is stored is first identified and the liquid crystalline material on this kinoform is activated by applying an electrical field across it. The identified kinoform is illuminated with coherent light and the data sequence stored on the kinoform is retrieved by decoding the optical signal received at a target sensor.

In yet another aspect the present invention includes a system for high-speed switching of optically-encoded digital information having at least an address portion and a data portion using a plurality of pre-shaped kinoforms through which a beam of light is projectable from an encoder to one or more target light sensors. The address portion of the digital information is first separated from the data portion. Each possible destination for the digital information is mapped to a specific kinoform that is designed to route the optically-encoded digital information to an identifiable target sensor. The data portion of the digital information is used to modulate the light beam and the address portion of the digital information is used to selectively activate the kinoforms that are associated with the sensors corresponding to the destination address(es) of the digital information. The optically-encoded data received at each target sensor is finally demodulated into digital form.BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and system of the present invention may be obtained by reference of the detailed description of the preferred embodiments that follows, taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 shows a cross-sectional view of a switchable kinoform;

FIGURE 2 shows the optical changes in the liquid crystal layer of the switchable kinoform of FIGURE 1 upon the application of an electrical field;

FIGURE 3 is a block diagram of an optical display device constructed in accordance with the principles of the present invention;

FIGURE 4 shows one method of constructing a kinoform sandwich;

FIGURE 5 shows another method of constructing a kinoform sandwich;

FIGURE 6 is a block diagram of an optical data storage and retrieval system constructed in accordance with the principles of the present invention; and

FIGURE 7 is a block diagram of an optical switching device constructed in accordance with the principles of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Device Structure

Referring first to FIGURE 1, there is shown a cross- sectional view of a switchable kinoform. The switchable kinoform 100 includes a substrate layer 101, which can be made of a non-conducting transparent material such as glass. A transparent conductive material 102 such as Indium-Tin Oxide (ITO) is deposited upon the substrate 101. A transparent photo-resistive layer 103 is deposited on top of the conductive electrode layer 102 by an appropriate process such as spin-coating. The photo¬ resistive layer 103 is etched using a device such as a laser beam writer and then developed to create a hologram- generating surface. In one such kinoform described in the prior art, the modulation depth, d, was about 6.6 micrometers, on a photo-resistive layer that was 10 micrometers thick. The steepest slope in the hologram-generating surface profile was about 3°. The etched hologram-generating surface is at least partially filled with liquid crystal to create a liquid crystal layer 104. A second transparent conductive material layer 106 is deposited on the underside of a transparent top sealant layer 107 and used to cap the liquid crystal filled hologram-generating surface.

It is sometimes necessary to have a non-conducting region 105 between the liquid crystal layer 104 and the transparent top electrode layer 106. The transparent top sealant 107 can be made of the same material as the substrate 101 i.e. of glass. Likewise, the top transparent electrode layer 106 can be made of the same material as the bottom transparent electrode layer 102 i.e. of Indium-Tin Oxide (ITO) .

Means, not shown, are provided to supply electrical voltage to the top and bottom electrodes 102 and 106 respectively, to form an electric field to change the alignment of the liquid crystal.

In the discussion that follows, the index of refraction of the liquid crystal varies between n and n . The index of refraction of the photo-resistive material used to create the hologram-generating surface is π _h . The liquid crystalline material used to fill the etched hologram-generating surface is selected so that n_e is as close as possible to n _h .

Device Physics

The optical changes in the liquid crystal layer of FIGURE 1 that result from the application of an electrical field are .illustrated in FIGURE 2. The degree of alignment of the liquid crystal molecules varies depending upon the potential difference between the top and the bottom transparent conductive electrode layers 102 and 106.

As shown in FIGURE 2, the phase difference between the polarization of the incident light at the point of incidence on the liquid crystal layer and at the plane of exit from the liquid crystal layer is zero when the voltage difference between the top and bottom electrodes is zero. When the applied voltage reaches the saturation voltage, V , the phase difference reaches a maximum of

— X ( n P^h -n °)d. When the phase difference is zero, incident light passes through the kinoform without interacting with the hologram-generating surface on that kinoform because the index of diffraction of the inactivate liquid crystalline material, n , becomes almost identical to the index of diffraction of the etched photo-resistive material, n ph . .

Optical Display Device Embodiment

FIGURE 3 shows a block diagram of an optical display device that can selectively display one of a plurality of images upon a screen. This embodiment of the present invention consists of a stack of kinoforms 301 to 305 connected to a control unit 310. A light beam 321 is projected from a light source 320 through these stacked kinoforms 301 to 305 and thence, to a reflective surface 330. The light beam 321 then passes through projection optics 340 and onto a screen 350 creating an image 360 upon the screen. Each of the kinoforms 301 to 305 contains an encoded etched image capable of being selectively activated by the control unit 310.

FIGURE 3 shows a plurality of stacked kinoforms 301 to 305, each of which is similar to the kinoform illustrated in FIGURE 1. A light source 320 provides a beam which passes through the stacked array 301 to 305. A control circuit 310 selectively energizes and controls the potential difference between adjacent layers so that selective ones of the holographic images on liquid crystal layers have a transformative affect on the beam of light passing from the source 320.

Thus, for example, a series of related images may be placed on selected ones of the kinoforms 301 to 305 in the stack and selectively or sequentially rendered opaque to the light while all the other kinoforms are made transparent to the light. Thus, a series of moving images can be projected onto the screen 350 as a moving display of images such as animation or the like for display or information purposes. Moreover, a sequence of images presenting a motion picture can also be created and projected in this way.

In an alternative embodiment of the present invention, screen 350 can be eliminated, permitting one or more observers to directly view two-dimensional or three-dimensional images singly or in sequence. Two- dimensional and three-dimensional displays of this kind can be used for presenting advertisements and motion pictures to an audience.

Fabrication of a Kinoform Sandwich

One technique for fabricating a kinoform sandwich is shown in FIGURE 4. For simplicity of illustration, FIGURE 4 shows only the structural details of two adjacent kinoforms. Kinoforms 1 and 2 shown in FIGURE 4 are largely identical in construction detail to the kinoform shown in FIGURE 1.

Thus, Kinoform 1 comprises a substrate layer 401 upon which a transparent electrode layer 402 is deposited. A transparent photo-resistive material 403 is deposited upon this conductive electrode layer 402 and etched to create a hologram-generating surface 420. A liquid crystal layer 404 is created by filling the top of the etched hologram- generating surface 420 with liquid crystalline material. A top conductive electrode layer 406 and a top sealant layer 407 are above the liquid crystalline layer 404 and an optional non-conductive region 405 (not shown) . The electrodes 402 and 406 on Kinoform 1 are connected to the control unit 440 via electrical leads 441 and 442, respectively. The construction of Kinoform 2 is identical to that of Kinoform 1. For clarity of illustration, the optional non-conducting regions 405 and 415 of Kinoforms 1 and 2 respectively are not shown in FIGURE 4.

Another technique of fabricating a kinoform sandwich is illustrated in FIGURE 5. As can be seen, the electrode layers 406 and 412 and the sealant layers 407 and 411 of FIGURE 4 have all been replaced by a single electrode layer 506 in FIGURE 5. The structure shown in FIGURE 5 is particularly easier to fabricate when a kinoform sandwich is built up layer by layer starting with the lowest substrate layer 501 and ending with the top sealant layer 511. On the other hand, when each element of a kinoform sandwich needs to be assembled after separate manufacture, then the fabrication technique shown in FIGURE 4 is likely to prove easier to implement.

Optical Data Storage and Retrieval System

Referring next to FIGURE 6, there is shown a system for enabling the selective access to one of a plurality of data sources, containing, for example, optically-encoded digitized audio-visual information. The system includes a plurality of stacked hologram-generating kinoforms 601 to 604, each of which is similar to the sandwiched kinoform structures described above in connection with the description of FIGURE 3.

Each of the kinoforms 601 to 604 contains an hologram-generating surface that can include, for example, concentric or spiral tracks of data. A light source 621 generates a light beam 630 which can be articulated in a regular pattern and which is capable of following the pattern of the data tracks on respective ones of the kinoforms 601 to 604. A light detector 640 receives light passing through the stack of kinoforms 601 to 604.

A control circuit 610 selectively controls the voltage across various ones of the liquid crystal layers on the kinoforms 601 to 604 so that only one of the layers 601 to 604 may be selectively energized to deflect or interrupt the beam 630 and thereby affect reception of the beam at detector 640 and communicate the information contained on the associated one of the kinoforms 601 to 604 to the detector-decoder 640.

It should be noted that the kinoforms in this embodiment are not used to generate holographic images but are instead used only to store digital information that can be optically read and written. The optical assembly 620 consists of a semi-transparent reflector 622 and a light source 621 rotatably mounted upon a sleeve 623. Sleeve 623 is slidably mounted upon a slider bar 624. This arrangement permits the light source to be rotated about the axis 625. Means, not shown, permit the semi- transparent reflector 622 to follow the light source while reflecting the spatially-variant reflected light beam to a spatially-fixed detector-decoder 640.

It should be noted that in this embodiment of the invention, means for dynamically writing, recording or erasing information may optionally be present. Such means are not shown in FIGURE 6. Digital information can be written on a kinoform by changing the shape of the diffracting surface in a manner that could be practiced by one skilled in the art.

Optical Switching Device Referring finally to FIGURE 7, there is shown a further embodiment of the system of the present invention comprising an optical switch. The optical switching device shown in FIGURE 7 comprises a plurality of N kinoforms 731 to 735. Input data 701 comprising of an address portion and a data portion is converted by a decoder-analyzer 710 into a separate data portion 711 and an address portion 712. The data portion 711 is used to modulate the output of a light emitting source 720. Kinoforms 731 to 735 are controlled by a kinoform control unit 740. The address portion 712 of the input information 701 is routed to the kinoform control unit 740 and used by the kinoform control unit to selectively activate one of the N kinoforms 731 to 735.

The N kinoforms are so shaped that if any of them is activated, it will route an incoming optical signal to a specific target sensor corresponding to that kinoform. Thus, if kinoform 731 is activated by the kinoform control unit 740, it routes the optically-modulated encoded communications data 711 along path 771 to target sensor 761. Similarly if kinoform 732 is activated, it routes the communications data 711 along path 772 to the target sensor 762.

The stacked kinoforms 731 to 735 are connected to the kinoform control unit 740. A light source 720 produces a modulated light beam 721, for example, carrying encoded communications data, which is projected onto the stacked kinoforms 731 to 735. If the image placed on the hologram associated with the first device 731 is chosen such that the beam is deflected toward a first target optical sensor 761 along a path 771, data will be communicated from the source 720 to the target 761. If, however, the liquid crystal layer of the device 731 is rendered transparent and the liquid crystal layer of the device 732 is rendered opaque so as to deflect the modulated light beam towards a second target sensor 762 along a path 772, then optical switching has been effected as a result of changing the voltage on the respective layers of the two device. It should be understood that as many additional layers can be added as are necessary to properly size the switch shown in FIGURE 7. It is also possible to use a kinoform sandwich for multicasting. By selectively activating more than one kinoform at the same time, a single input can be routed to multiple outputs. This group- addressing technique can be used for broadcasting input signals. Although a preferred embodiment of the method and apparatus of the present invention has been illustrated in the accompanying drawings and described in the foregoing detailed description, it is to be understood that the invention is not limited to the embodiment (s) disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit of the invention as set forth and defined by the following claims .

Claims

WHAT IS CLAIMED IS:

1. A method of selectively projecting one of a plurality of images using illumination generated by a light source, said method comprising the steps of: arranging a plurality of stacked layers on parallel planes with the planar surface of each layer extending generally transversely to the illumination, each of said stacked layers further comprising: a planar film that is bounded on its lower surface by a flat transparent support and on the' upper surface of which a first holographic pattern is formed, said holographic pattern having varying depths at different points on the surface of the film, thereby creating void areas of varying depths over the surface of the planar film; a pair of transparent conductive layers adjacent to the upper and lower surfaces of said planar film; and a quantity of liquid crystalline material positioned within the void areas on the upper surface of each of said planar films, said liquid crystalline material having a first ordinary index of refraction in the presence of an electric field and second extraordinary index of refraction in the absence of an electric field, said extraordinary index of refraction being selected to be approximately equal to the index of refraction of the planar film with which it is in contact; sealing the stack into a unitary structure by placing layers of transparent sealing material above and below said stacked layers; and varying the electric potential between a selected pair of adjacent transparent conductive layers in order to: cause the liquid crystalline material between said adjacent transparent conductive layers to have an index of refraction that is substantially different from the index of refraction of the planar film that is adjacent to said liquid crystalline material so that the holographic image formed thereby interacts with the illumination to produce a first image; and cause the liquid crystalline material on all of the non-selected stacked layers to have an index of refraction that is substantially equal to the index of refraction of the planar film on those layers so that the non-selected layers are rendered substantially transparent to the illumination and the holographic patterns therein become invisible.

2. A system for selectively projecting one of a plurality of images using illumination generated by a light source, said system comprising: a plurality of stacked layers each lying in parallel planes and positioned with the planar surface of each layer extending generally transversely to the illumination, each of said stacked layers further comprising: a planar film that is bounded on its lower surface by a flat transparent support and on the upper surface of which a first holographic pattern is formed, said holographic pattern having varying depths at different points on the surface of the film, thereby creating void areas of varying depths over the surface of the planar film; a pair of transparent conductive layers adjacent to the upper and lower surfaces of said planar film; and a quantity of liquid crystalline material positioned within the void areas on the upper surface of each of said planar films, said liquid crystalline material having a first ordinary index of refraction in the presence of an electric field and second extraordinary index of refraction in the absence of an electric field, said extraordinary index of refraction being selected to be approximately equal to the index of refraction of the planar film with which it is in contact; layers of transparent sealing material above and below said stacked layers that seal the stack into a unitary structure; and means for varying the' electric potential between a selected pair of adjacent transparent conductive layers in order to: cause the liquid crystalline material between said adjacent transparent conductive layers to have an index of refraction that is substantially different from the index of refraction of the planar film that is adjacent to said liquid crystalline material so that the holographic image formed thereby interacts with the illumination to produce a first image; and cause the liquid crystalline material on all of the non-selected stacked layers to have an index of refraction that is substantially equal to the index of refraction of the planar film on those layers so that the non-selected layers are rendered substantially transparent to the illumination and the holographic patterns therein become invisible.

3. A method for selectively projecting one or more encoded images stored on a plurality of kinoforms, said method comprising the steps of: storing an encoded image on a kinoform by a method comprising the following steps: forming an encoded image on a transparent first material having a first index of refraction; filling the voids in said formed transparent first material with liquid crystalline material having a second index of refraction when activated by an electrical field and a third index of refraction when no electrical field is applied, said third index of refraction being approximately equal to said first index of -refraction and•being different from said second index of refraction; and depositing a first and a second transparent conductive film adjacent to said formed transparent first material to act as electrodes for applying an electrical field to the liquid crystalline material, said first and second transparent conductive films being arranged on substantially parallel planes on opposing sides of said formed transparent first material; aligning all the kinoforms containing stored encoded images into a stack; selecting an image stored on a particular kinoform by activating the liquid crystalline material on said kinoform, the activation being done by applying an electrical field across the liquid crystalline material; illuminating said selected image using coherent light from a light source; and projecting said illuminated image in a viewable form.

4. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the method of storing an encoded image on a kinoform additionally comprises the additional step of creating a non-conductive region between the liquid crystal and one of the adjacent transparent conductive layers.

5. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the- step of aligning all the kinoforms containing stored images into a stack is performed by assembling separately created self-contained kinoforms into a stack.

6. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the step of aligning all the kinoforms containing stored images into a stack is performed by unitary manufacture of the stacked kinoform layer by layer.

7. The method of Claim 6 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the unitary manufacture of the stacked kinoform layer by layer additionally includes combining the bottom transparent conductive film of one kinoform with the top transparent conductive film of the kinoform beneath it.

8. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the images are projected in a predetermined order.

9. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are projected in an order determined by user input.

10. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said first and second transparent conductive films are located above and below said transparent first material .

11. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said transparent first material is photo-resistive and said encoded images are formed thereon by photo-etching.

12. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by thermo-optical means.

13. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by mechanical means.

14. The method of Claim 3 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by electro-magnetic means.

15. A system for selectively projecting one or more encoded images stored on a plurality of kinoforms, said system comprising: means for storing an encoded image on a kinoform by a method.comprising the following steps: forming an encoded image on a transparent first material having a first index of refraction; filling the voids in said formed transparent first material with liquid crystalline material having a second index of refraction when activated by an electrical field and a third index of refraction when no electrical field is applied, said third index of refraction being approximately equal to said first index of refraction and being different from said second index of refraction; and depositing a first and a second transparent conductive film adjacent to said formed transparent first material to act as electrodes for applying an electrical field to the liquid crystalline material, said first and second transparent conductive films being arranged on substantially parallel planes on opposing sides of said formed transparent first material; means for aligning all the kinoforms containing stored encoded images into a stack; means for selecting an image stored on a particular kinoform by activating the liquid crystalline material on said kinoform, the activation being done by applying an electrical field across the liquid crystalline material; means for illuminating said selected image using coherent light from a light source; and means for projecting said illuminated image in a viewable form.

16. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the method of storing an encoded image on a kinoform additionally comprises the additional step of creating a non-conductive region between the liquid crystal and one of the adjacent transparent conductive layers.

17. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the means for aligning all the kinoforms containing stored images into a stack additionally comprises means for assembling separately created self-contained kinoforms into a stack.

18. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the means for aligning all the kinoforms containing stored images into a stack additionally comprises unitary manufacture of the stacked kinoform layer by layer.

19. The system of Claim 18 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein the unitary manufacture of the stacked kinoform layer by layer additionally includes combining the bottom transparent conductive film of one kinoform with the top transparent conductive film of the kinoform beneath it.

20. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality. of kinoforms wherein the images are projected in a predetermined order.

21. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are projected in an order determined by user input.

22. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said first and second transparent conductive films are located above and below said transparent first material.

23. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said transparent first material is photo-resistive and said encoded images are formed thereon by photo-etching.

24. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by thermo-optical means.

25. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by mechanical means.

26. The system of Claim 15 for selectively projecting one or more encoded images stored on a plurality of kinoforms wherein said encoded images are formed on the transparent first material by electro¬ magnetic means.

27. A method for the storage and retrieval of data sequences comprising the steps of : storing a plurality of encoded data sequences on a kinoform; indexing each of said stored data sequence so as to permit the identification of specific data sequences; identifying a kinoform on which a specific data sequence is stored; activating the liquid crystalline material on said identified kinoform by applying an electrical field across said liquid crystalline material; illuminating said identified kinoform using coherent light from a light source; and retrieving the data sequence stored on said identified kinoform by decoding the optical signal received from said illuminated kinoform.

28. A system for the storage and retrieval of data sequences comprising: means for storing a plurality of encoded data sequences on a kinoform; means for indexing each of said stored data sequence so as to permit the identification of specific data sequences; means for identifying a kinoform on which a specific data sequence is stored; means for activating the liquid crystalline material on said identified kinoform by applying an electrical field across said liquid crystalline material; means for illuminating said identified kinoform using coherent light from a light source; and means for retrieving the data sequence stored on said identified kinoform by decoding the optical signal received from said illuminated kinoform.

29. A method for high-speed switching, using a plurality of pre-shaped kinoforms, of optically-encoded digital information originating from an encoder to one or more of a plurality of target light sensors, the digital information comprising at least an address portion and a data portion, said method comprising the steps of: separating the address portion of the digital information from the data portion of the digital information; mapping each possible destination for the digital information to a specific kinoform designed to route optically-encoded digital information to an identifiable target sensor; modulating the beam of light from the light source to generate optically-encoded data using the data portion of the digital information; routing the optically-encoded beam of light through a stack of kinoforms; selectively activating the specific kinoforms that are associated with the sensors corresponding to the destination of the digital information; and demodulating the optically-encoded data received at each target sensor into digital form.

30. The method of Claim 29 for the high-speed switching of digital information wherein the kinoforms comprise a diffraction element capable of redirecting said incident light beam towards a target sensor.

31. The method of Claim 29 for the high-speed switching of digital information wherein only one kinoform is activated at a given time.

32. The method of Claim 29 for the high-speed switching of digital information wherein more than one kinoform is activated at a given time.

33. A system for high-speed switching, using a plurality of pre-shaped kinoforms, of optically-encoded digital information originating from an encoder to one or more of a plurality of target light sensors, the digital information comprising at least an address portion and a data portion, said system comprising: means for separating the address portion of the digital information from the data portion of the digital information; means for mapping each possible destination for the digital information to a specific kinoform designed to route optically-encoded digital information to an identifiable target sensor; means for modulating the beam of light from the light source to generate optically-encoded data using the data portion of the digital information; means for routing the optically-encoded beam of light through a stack of kinoforms; means for selectively activating the specific kinoforms that are associated with the sensors corresponding to the destinations of the digital information; and means for demodulating the optically-encoded data received at each target sensor into digital form.

34. The system of Claim 33 for the high-speed switching of digital information wherein the kinoforms comprise a diffraction element capable of redirecting said incident light beam towards a target sensor.

35. The system of Claim 33 for the high-speed switching of digital information wherein only one kinoform is activated at a given time.

36. The system of Claim 33 for the high-speed switching of digital information wherein more than one kinoform is activated at a given time.