WO1999008257A1

WO1999008257A1 - Liquid crystal controlled display apparatus

Info

Publication number: WO1999008257A1
Application number: PCT/GB1998/002356
Authority: WO
Inventors: Allan John Davie
Original assignee: Allan John Davie
Priority date: 1997-08-05
Filing date: 1998-08-05
Publication date: 1999-02-18
Also published as: AU8639498A

Abstract

Display apparatus is described which has an electronically controlled illuminated display for presenting a changeable or animated visual display. An electronically controllable optical shutter (14) in the form of a liquid crystal display (LCD) is placed adjacent to a colour slide (16). By illuminating the slide (16) with a light source (12) and actuating a sequence of LCD shutter elements (30) parts of the slide image are sequentially displaced so that an observer perceives the displayed image to be animated. The display apparatus can be incorporated into a projector (80), timepieces such as a clock (91) or watch (120) and by using a pair of stereo images (142) of the same image, stereoscopic viewing apparatus (130) provides the perception of a three-dimensional animated image to an observer. Various embodiments of the invention are described. Thus the display appparatus is suitable for a variety of applications such as advertising, entertainment and education.

Description

LIQUID CRYSTAL CONTROLLED DISPLAY APPARATUS

The present invention relates to display apparatus. In particular, the invention relates to display apparatus having an electronically controlled illuminated display for presenting a changeable or animated visual display. It is known to project cinematographic films to produce an animated display; however, cinematographic films and projection apparatus are bulky and expensive. It is also known to use photographic slides to project a still (non-animated) image; this is a small and inexpensive method of producing an image, however, this system does not provide animation.

It is an object of one embodiment of the present invention to provide display apparatus having an illuminated image which appears to a viewer to be animated.

According to a first aspect of the present invention there is provided display apparatus comprising: a light source, controllable optical shutter means having at least two shutter elements, each of which is energisable between an optically transmissive state and an optically non-transmissive state for selectively transmitting or blocking emission from the light source, control means coupled to said at least two shutter elements for controlling an electrical signal to each of said shutter elements so that the shutter elements are either transmissive or non- transmissive in response to the electrical signal, and an image disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, so that, in use, the shutter elements are energised to change between transmissive and non- transmissive states to allow different parts of the image to be viewed to give the perception of animation to an observer.

The display apparatus may further include lens focusing means for receiving and focusing light from the light source so that the image is projected onto a viewing surface. Alternatively and/or additionally, the display apparatus may further include a diffuser for diffusing light from the light source.

Preferably, the controllable optical shutter means is a liquid crystal display having shutter elements of a predetermined shape to depict an image . LCDs have the advantage that they are small, light, require low power, and are easy to control. Alternatively, the controllable optical shutter means is a dot matrix screen. This gives the added advantage of programmability, so that the image which is projected may be changed in use. Preferably, the control means is a programmable memory having a counter to select addresses in the memory sequentially, where each memory address stores information which is used to control the shutter elements .

Preferably, there is a heat sink connected to the controllable optical shutter means to reduce build-up of heat on the shutter means. Conveniently, the heat sink is a frame that fits around the controllable optical shutter means to ensure that the heat sink does not block light from the controllable optical shutter means.

According to a second aspect of the present invention there is provided a method of displaying an animated image, the method comprising the steps of: providing a controllable shutter device having individually controllable shutter elements, providing an image in proximity to the controllable shutter device, where parts of the image are to be displayed, illuminating both the controllable shutter device and the image, and controlling the individually controllable shutter elements so that each of at least two shutter elements is energised between an optically transmissive state and an optically non-transmissive state to allow different parts of the image to be viewed on a viewing surface to give the perception of animation to an observer . Preferably, the method includes the step of projecting the image onto a remote viewing surface. Alternatively, the viewing surface is provided by the slide and controllable shutter device. Preferably, the method includes the step of providing a heat sink to dissipate heat from the shutter device and/or the image .

Preferably, the method includes the step of using a programmable controllable shutter device so that the shape of the shutter elements may be changed during use.

According to a third aspect of the present invention there is provided projection apparatus comprising: a projector, controllable optical shutter means having shutter elements, each of which is energisable to change between an optically transmissive state and an optically non-transmissive state, for selectively transmitting or blocking emission from the projector, control means coupled to each of said shutter elements for controlling an electrical signal to each of said shutter elements so that the shutter elements are either optically transmissive or optically non- transmissive in response to the electrical signal, and an image disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, so that in use individual shutter elements are energised to change between transmissive and non- ransmissive states, to allow different parts of the image to be projected to give the perception of animation to an observer viewing the projected image.

According to a fourth aspect of the present invention there is provided a timepiece including display apparatus according to the first aspect of the invention.

The timepiece may be a clock having a permanently displayed animated image. Alternatively, the timepiece may be a watch having an animated image energisable on actuation by the user.

Preferably, the light source in the timepiece is a low-energy requirement light source. Conveniently, the light source is an electro- luminescent panel. According to a fifth aspect of the present invention there is provided stereoscopic viewing apparatus comprising; controllable optical shutter means having shutter elements, each shutter element being changeable between an optically transmissive state and an optically non- transmissive state, for selectively transmitting or blocking emission from a light source, control means coupled to each of said shutter elements for controlling an electrical signal to each of said shutter elements so that each shutter element is either optically transmissive or optically non- transmissive in response to a respective electrical signal , at least one pair of images disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, the at least one pair of images being stereo images of a single image, which when viewed as separate images by each eye of an observer give the perception of a three dimensional image to the observer.

Preferably, the individual shutter elements are energised between transmissive and non-transmissive states to allow parts of the at least one pair of images to be viewed at a time.

The stereoscopic viewing apparatus may further include means for positioning the at least one pair of images between a light source and the observer. Preferably the means for positioning the at least one pair of images is a mechanical latch mechanism. Alternatively the means for positioning the at least one pair of images is manually operated by the observer. The stereoscopic viewing apparatus may further include one or more mirrors to direct the image to an observer's eye. Preferably one image from the pair of images is directed towards an observer's left eye and the other image is directed towards the observer's right eye. The apparatus may further include lens focusing means for receiving and focusing light from the light source so that the images are projected onto the observer's left eye and the observer's right eye.

According to a sixth aspect of the present invention there is provided an animated stereoscopic viewing apparatus according to the fifth aspect of the invention. Preferably the individual shutter elements are energised between transmissive and non-transmissive states to allow different parts of the at least one pair of images to be viewed to give the perception of animation to the observer

These and other aspects of the present invention will become apparent from the following specific embodiments, given by way of example, with reference to the accompanying drawings m which:

Fig 1 is a schematic diagram of an embodiment of the present invention;

Fig 2 is a diagrammatic view of an electronically controlled display used m Fig. 1,

Fig. 3 snows a circuit boarα populated with components for controlling the display shown m Fig. 2,

Fig. 4 snows a block diagram of an electronic circuit for controlling the display of Fig. 2, Fig. 5 shows a block diagram of an alternative electronic circuit to that of Fig. 4,

Fig 6 snows a controlled electronic display similar to that shown m Figs 1 to 4 m comoinat on with a conventional photographic slide projector, Fig. 7 snows a diagram of an application of an embodiment of the present invention, and

Fig. 8 is a diagrammatic exploded view of a bacK-lit display m accordance with an alternative embodiment of the present invention; Figs. 9a and 9b illustrate another application of an embodiment of the present invention,

Fig. 10 s a side view of a portion of the Figs. 9a and 9b emboα men , Fig. 11 is a schematic view of an integrated circuit for use with the embodiments of Figs. 9a and 10;

Fig. 12 shows a schematic diagram of another application of an embodiment of the present invention, and

Fig. 13 is a diagrammatic view of an electronically controlled display used in Fig. 12.

Fig. 1 shows a schematic diagram of a system 10 for projecting a moving colour display. The system 10 is suitable for a variety of applications such as advertising, entertainment, and education.

The system 10 comprises a light source 12 for emitting visible light, electronically controllable optical shutter means 14 in the form of a liquid crystal display (LCD) , a colour slide 16 adjacent to and in contact with the LCD 14, a lens 18 for focusing light transmitted through the LCD 14/colour slide IS combination onto a screen 20, control means 22 for controlling the LCD 14 via control conductors 24, and a heat sink 26 around the perimeter of the LCD 14/colour slide 16 combination.

The light source 12 and lens 18 is provided by a projector arrangement similar to those used to project images of photographic transparencies . Referring to Fig. 1 and Fig. 2, Fig. 2 shows the diagrammatic view of the LCD 14 of Fig. 1. The LCD 14 has a plurality of electrode shutter elements 30 (for clarity, only some of these elements are labelled, elements which will be^" referred to in this description are labelled 30a to 30m) defined on its surface which are electrically energisable between an "on" state and an "off" state to act as optical shutters. An LCD 14 may be designed with any convenient number of shutter elements 30, and the shutter elements 30 may be of any shape; however, the shape of a shutter element 30 on an LCD 14 is defined when the LCD is fabricated.

The control means 22 is an electronic circuit which controls the signals delivered to each electrode element 30a to 30m, and which thereby determines the energisation sequence of the electrode elements . When an electrode element 30 is transparent then light from the light source 12 illuminates the portion of the colour slide 16 corresponding to the position of the electrode element 30. Conversely, when an electrode element 30 is opaque then the corresponding portion of the colour slide 16 is not illuminated. The control means 22 energises the electrode shutter elements 30 as required, which gives the overall effect of the LCD 14 stepping through a sequence of static images with a short time interval between neighbouring static images in the sequence. An observer viewing this concatenated sequence of images perceives the continuously changing images as animation. Fig. 3 shows a circuit board 32 incorporating the

LCD 14 and the control means 22. The control means 22 comprises an integrated circuit 34, resistive components (R1,R2,R3 ,R ,RP1) , capacitive components (Cl , C2 , C3 , C4 ) , a battery (Bl) and an oscillator (XI) . Table 1 gives typical values of these components .

Fig. 4 shows a block diagram of the integrated circuit 34. The integrated circuit 34 has an N bit binary counter 42 which is connected to a decoder 44 for decoding the output state of the counter 42. The decoder 44 has 2N outputs 46 that are connected to a pre-programmed programmable read-only memory (PROM) 43. Each output 46 is used to select a different but predetermined address in the PROM 48. The decoder 44 also has a reset output 50 which is used to reset the binary counter 42 after a specified number of steps. When the binary counter 42 is reset, the sequence of addresses that are selected by the decoder 44 is repeated.

The PROM 48 has M (where M corresponds to the number of electrode shutter elements 30) parallel outputs 52 which are connected to LCD drivers 54 which also have M parallel outputs 56 which are connected to the front plane electrodes (not shown in the interests of clarity) of the LCD 14.

A first oscillator 58 is connected to the counter 42, and a second oscillator 60 is connected to the LCD drivers 54 and to the back plane electrode (not shown) of the LCD 14. The frequencies of the first and second oscillators 58 and 60 are set by the values of an external resistive component and capacitive component as shown m Fig . 3. Power is supplied 'to the circuit 34 via terminals 62 and 64. The data in the PROM 48 which has been addressed by the counter outputs 46 is transferred in parallel rows by the PROM outputs 52 to the LCD drivers 54 in accordance with the frequency of the first oscillator 58. An alternating supply 63 also enters the LCD drivers 54 from the second oscillator 60. The visual display data transferred to the front plane electrodes by outputs 56 is derived from alternating signals from the second oscillator 60 such that the visual display data is either in phase or in anti -phase with the signal to the back plane electrode. The binary data transferred to the LCD drivers 54 by the PROM outputs 52 determines whether the visual display data is in phase or in anti-phase with the signal to the back plane electrode. Signals in anti-phase cause the electrode shutter elements 30 to darken while those in phase cause the electrode shutter elements 30 to remain transparent.

The visual display data is transferred from the LCD drivers 54 to the LCD electrodes 30 in accordance with the frequency of the second oscillator 60, the frequency of which is typically 100Hz to prevent deterioration of the LCD. Thus, data signals are presented to the front plane electrodes in phase, or in anti-phase, with signals from the second oscillator 60 to the back plane electrode of the LCD.

The visual display thus presented is representative of the particular row of data read from the PROM 48. The visual display presented is continuously changed in accordance with the program in the PROM 48 and the frequency of change is controlled by the first oscillator 58, which has a value of typically 0.1Hz to 2Hz . Thus, a viewer watching a projected image from the

LCD 14 observes areas of the projected image changing between dark and coloured, thereby giving the appearance of animation. This appearance of animation is enhanced if the shutter elements 30 depict the same general image but in apparently slightly different positions. For example, in Fig 2 the shutter elements may be transmissive or non-transmissive during each step as shown in Table 2. This cycle may be repeated continuously, giving the impression that the train (depicted by 30a and 30b) is moving because the smoke from the train (depicted by 30j, 30k, 301), the bird (depicted by 30e, 30f , 30g, 30h) , and the fence (30m) are energised to provide this illusion of movement of the train. It will be appreciated that, for the sake of clarity and simplicity, only some of the shutter elements in Fig. 2 are labelled and described; whereas in practical embodiments all of the shutter elements shown in Fig. 2 are used. Thus, there are eleven shutter elements representing a bird in Fig. 2, but only four of these elements (30e, 30f, 30g, 30h) are labelled and described .

The number of electrodes of the LCD and the number of steps in the display sequence (2N) should be as large as possible to provide maximum versatility.

Referring now to Fig. 5, an N-bit shift register 70 and NOR gate 72 are connected to the PROM 48 instead of the counter 42 and decoder 44 of Fig. 4. A latch buffer 74 is also inserted between the PROM outputs 52 and the LCD drivers 54. The outputs 76 of the latch buffer 74 are connected to the LCD drivers 54, and the first oscillator is also connected to the latch buffer 74, otherwise the circuit is the same as for Fig. 4. In use, the shift register 70 is clocked by the first oscillator 58 which then sends an electrical signal corresponding to a logic "1" to the PROM 48, enabling data corresponding to a particular visual display to be read. The NOR gate 72 ensures that there is only one logic "1" in the shift register 70 at any one time. The data which has been read is transferred in M parallel rows by the PROM outputs 52 to the latch buffer 74. The data is then transferred from the latch buffer 74 to the LCD drivers 54 via outputs 76 in accordance with the frequency of the first oscillator 58. The control of the display (LCD 14 in Fig 1) by the second oscillator 60 is the same as for the Fig. 4 embodiment. The external resistor of the second oscillator 60 is variable so that the frequency of the change of the visual display can be adjusted manually.

Fig. 6 shows the device 32 of Fig. 3 inserted into a conventional slide projector 80, in accordance with another embodiment of the present invention. Fig. 7 shows a diagram of one application of an embodiment of the present invention in a bedroom 82 with a bedside lamp 84 to project an image onto the bedroom ceiling 86 to provide what appears to be animation. Fig. 8 is a diagrammatic exploded view of an illuminatable animated back-lit display system 90 according to an embodiment of the present invention. The system 90 is disposed in a housing 91. The animated back-lit display 90 comprises a light source 12 consisting of fuse bulbs; an optical reflector 92 disposed to the rear of the light source 12; a translucent diffuser 94 disposed to the front of the light source 12; electronically controllable optical shutter means (consisting of an LCD) 14 located at the front of the display 90; and a colour slide 16 disposed between the LCD 14 and the diffuser 94. The LCD 14 has a relatively small viewing area, for example 100mm by 100mm. A small portion of this viewing area (the clock area 96) has a clock permanently displayed. The remaining portion of the viewing area (the image area 98) is used to display what appears to be a moving image in a similar way as described with reference to Fig. 2. The clock area 96 is controlled by a 4 or 8 bit microprocessor 100. In use, an electrical current passing through the fuse bulbs causes the bulbs to light up. The light from the bulbs and reflected light from the reflector 92 passes through the translucent diffuser 94 and through the colour slide 16. The LCD elements of the shutter 14 control 'the light presented to a viewer so that the image is back- lit and appears animated as described above. The microprocessor 100 may be a separate unit or may be incorporated in the control means 22.

The display 90 may be used in many different applications, for example, as a night light having a digital clock, part of a clock radio or radio cassette player or the like, or as a device at a point of sale. Fig. 9a illustrates a wrist watch 120 in accordance with another embodiment of the present invention. The watch 120 comprises a strap 122 and a watch body 124; the watch body 124 incorporating backlit liquid crystal display apparatus similar to that previously described with reference to Figs. 1 to 5 where the light source 12 is a low energy requirement source such as an electroluminescent (S-L; film, also known as an electroluminescent panel, as will be described in detail below. The watch body 124 (shown enlarged in Fig. 9b) has a clock area 96 (similar to conventional wrist watches) for permanently displaying the time, and an image area 98 for displaying what appears to be a moving image in a similar way to that described with reference to Figs . 1 to 5. The watch body 124 also has a transparent cover 126 through which the image area 98 is visible. To conserve battery life, the watch body 124 only displays the moving image in response to an actuation command from the user, for example by the user depressing an actuation button on the watch body 124.

Fig. 10 is a side view of the liquid crystal display apparatus 130 incorporated in the watch 120 shown in Figs. 9a and 9b. The apparatus 130 comprises a colour slide 16 disposed adjacent to the transparent protective watch cover 126 for viewing therethrough; a light source 12 in the form of an electro- luminescent (E-L) panel, and an LCD shutter 14 disposed between the slide 16 and the E-L panel 12. The E-L panel 12 is a thin (0.17mm) multilayer sheet containing fluorescent dyes dispersed in a binder having a high dielectric constant . The dyes emit light when subjected to an alternating electric field. The electric field is generated by applying an alternating voltage of approximately 100V at 1000Hz across the narrow dimension of the panel 12. E-L panels are manufactured by Sεikosha and supplied by Hero Electronics, Dunstable Street, Ampthiil, Bedfordshire.

The high voltage (100V) is generated from the watch battery (typically a 3V battery) using a voltage generating integrated circuit 150 as shown in Fig. 11. Voltage generating integrated circuit 150 is an HV805 (supplied by Supertex Inc.) . A 3V supply line 152 connects the watch' s battery (not shown) to integrated circuit 150. The E-L panel 12 consumes typically 10mA, which is too large a value for the watch battery to supply constantly. The E-L panel 12 is only energised in response to a watch button being depressed. On depression of that button, the enable line 156 is brought low for a predetermined time, which causes the E-L panel 12 to be energised When the E-L panel 12 is energised a backlit image is displayed, which appears to be animated, as descrioed previously.

Fig 12 illustrates a stereoscopic viewer 130 in accordance with another embodiment of the present invention. The stereoscopic viewer 130 comprises eyepieces 138a and 138b, an arrangement of mirrors 134a, 134b, 134c and 134d, a positioner 132 and display apparatus similar to that previously described with reference to Figs. 1 to 5.

Fig. 13 shows a diagrammatic view of the LCD 145 of Fig. 12. LCD 145 has a plurality of paired images, 142a and 142b, 144a and 144b, 146a and 146b, and each image is similar to tnat previously described as LCD 14 Each pair of images 142,144,146 comprise a left image 142a, 144a, 146a and a right image 142b, 1446 , 146b . The left image and the right image are stereo images of a single image, which when viewed using this apparatus appear as a three dimensional image.

Shutter elements, as described in Fig. 2, operate n unison on a selected pair of images 142,144,146 to reveal parts of the three dimensional image and, if the shutter elements depict the same general image but m apparently slightly different positions, the three dimensional image appears to be animated.

In use tne observer positions the eyepieces 138a, 138b over their left and right eye respectively. They then direct the stereoscopic viewer 130 towards a light source. The positioning device 132 moves the LCD 145 until one pair of images 142,144,146 can be viewed. The mirror arrangement 134a, 134b, 134c , 34d directs the projected images onto the observer's eyes. Image 142a is projected onto mirrors 134b and 134a to be focused by eyepiece 138a onto the observer's left retina. At the same time, image 142b is projected onto mirrors 134c and 134d, to be focused by eyepiece 138b onto the observer's right retina. Because the pair of images 142a and 142b are stereo images a parallax effect is produced giving the sensation of depth and the visible effect of a three dimensional animated image positioned at infinity. Various modifications may be made to the above described embodiments within the scope of the present invention. For example, in other embodiments, the LCD 14 and LCD 145 may be replaced with an addressable dot matrix screen. This would have the advantage that the shape of each shutter element 30 is programmable, therefore the number, size, and shape of these areas 30 may be varied in use. For example, in a reel projection system where there is a reel of sequential slide frames, each frame may have a bar code or the like which provides a code to change the programmable shutter for specific frames so that not only does the frame/slide change but the shutter silhouette also changes. In other embodiments, the colour slide 16 may be movable to provide the possibility of changing the colours which are projected. In other embodiments, a black and white slide, or grey-scale slide may be used rather than a colour slide. Light sources other than fuse bulbs may be used in the second embodimen .

Table

a le 2

Claims

1. Display apparatus comprising: a light source, controllable optical shutter means having at least two shutter elements, each of which is energisable between an optically transmissibe state and an optically non-transmissive state for selectively transmitting or blocking emission from the light source, control means coupled to said at least two shutter elements for controlling an electrical signal to each of said shutter elements so that the shutter elements are either transmissive or non-transmissible in response to the electrical signal, and an image disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, so that, in use, the shutter elements are energised to change between transmissive and non- transmissive states to allow different parts of the image to be viewed to give the perception of animation to an observer.

2. Apparatus as claimed in claim 1 including lens focusing means for receiving and focusing light from the light source so that the image is projected onto a viewing surface .

3. Apparatus as claimed in claim 1 or 2 including a diffuser for diffusing- light from the light source.

4. Apparatus as claimed in any preceding claim wherein the controllable optical shutter means is a liquid crystal display having shutter elements of a predetermined shape to depict an image .

5. Apparatus as claimed in any of claims 1 to 3 wherein the controllable optical shutter means is a dot matrix screen .

6. Apparatus as claimed in any preceding claim wherein the control means is a programmable memory having a counter to select addresses in the memory sequentially, where each memory address stores information which is used to control the shutter elements .

7. Apparatus as claimed in any preceding claim wherein the said apparatus includes controllable optical shutter means to reduce build-up of heat on the shutter means .

8. Apparatus as claimed in claim 7 wherein the heat sink is a frame that fits around the controllable optical shutter means to ensure that the heat sink does not block light from the controllable optical shutter means

9. A method of displaying an animated image, the method comprising the steps of, providing a controllable shutter device having individually controllable shutter elements, providing an image in proximity to the controllable shutter device, where parts of the image are to be displayed, illuminating both the controllable shutter device and the image, and controlling the individually controllable shutter elements so that each of at least two shutter elements is energised between an optically transmissible state and an optically non-transmissive state to allow different parts of the image to be viewed on a viewing surface to give the perception of animation to an observer.

10. A method as claimed in claim 9 including the step of projecting the image onto a remote viewing surface.

11. A method as claimed in claim 9 wherein the viewing surface is provided by the slide and controllable shutter device .

12. A method as claimed in any one of claims 9 to 11 including the step of providing a heat sink to dissipate heat from the shutter device and\or the image .

13. A method as claimed in any one of claims 9 to 12 including the step of using a programmable controllable shutter device so that the shape of the shutter elements may be changed during use .

14. Projection apparatus comprising: a projector, controllable optical shutter means having shutter elements, each of which is energisable to change between an optically transmissive state an optically non- transmissive state, for selectively transmitting or blocking emission from the projector, control means coupled to each of said shutter elements for controlling an electrical signal to each of said shutter elements so that the shutter elements are either optically transmissive or optically non- transmissive in response to the electrical signal and an image disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, so that in use individual shutter elements are energised to change between transmissive and non- transmissive states, to allow different parts of the image to be projected to give the perception of animation to an observer viewing the projected image.

15. A timepiece including display apparatus as claimed in any one of claims 1 to 8.

16. A timepiece as claimed in claim 15 wherein the said timepiece is a clock having a permanently displayed animated image.

17. A timepiece as claimed in claim 15 wherein the said timepiece is a watch having an animated image energisable on actuation by the user.

18. A timepiece as claimed in any one of claims 15 to 17 wherein the light source in the timepiece is a low-energy requirement light source.

19. A timepiece as claimed in claim 18 wherein the light source is an electro-luminescent panel.

20. Stereoscopic viewing apparatus comprising: controllable optical shutter means having shutter elements, each shutter element being changeable between an optically transmissive state and an optically non- transmissive state, for selectively transmitting or blocking emission from a light source, control means coupled to each of said shutter elements for controlling an electrical signal to each of said shutter elements so that each shutter element is either optically transmissive or optically non- transmissive in response to a respective electrical signal, at least one pair of images disposed on an optically transmissive substrate and disposed in proximity to the controllable shutter means, the at least one pair of images being stereo images of a single image, which when viewed as separate images by each eye of an observer, give the perception of -a three dimensional image to the observer.

21. Stereoscopic viewing apparatus as claimed in claim 20 wherein the individual shutter elements are energised between transmissive and non-transmissive states to allow parts of the at least one pair of images to be viewed at a time.

22. Stereoscopic viewing apparatus as claimed in claims 20 or 21 including means for positioning the at least one pair of images between a light source and the observer.

23. Stereoscopic viewing apparatus as claimed in claim 22 wherein the means for positioning the at least one pair of images is a mechanical latch mechanism.

24. Stereoscopic viewing apparatus as claimed in claim 22 wherein the means for positioning the at least one pair of images is manually operated by the observer.

25. Stereoscopic viewing apparatus as claimed in any one of claim 20 to 24 including one or more mirrors to direct the image to an observer's eye.

26. Stereoscopic viewing apparatus as claimed in any one of claims 20 to 25 including lens focusing means for receiving and focusing light from the light source so that the images are projected onto the observer's left eye and the observer's right eye.

27. Animated stereoscopic viewing apparatus including stereoscopic viewing apparatus as claimed in any one of claims 20 to 26.

28. Animated stereoscopic viewing apparatus as claimed in claim 27 wherein the individual shutter elements are energised between transmissive and non-transmissive states to allow different parts of the at least one pair of images to be viewed to give the perception of animation to the observer.