Computer-based image display systems having direct and projection modes of viewing

• US 5,828,427 A
• Filed: 04/21/1994
• Issued: 10/27/1998
• Est. Priority Date: 06/11/1990
• Status: Expired due to Fees

• Current Assignee: Reveo, Inc.
• Original Assignee: Reveo, Inc.
• Inventors: Faris, Sadeg M.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/230,779
• Time in Patent Office: 1,650 Days
• Field of Search: 359/41, 359/50, 359/51, 359/53, 359/63, 359/69, 359/465, 353/119, 353/122, 353/DIG. 3, 353/DIG. 5, 353/71, 353/72, 345/32, 345/104, 362/31, 362/32, 385/129, 385/130, 385/901, 364/231.1, 349/5, 349/15, 349/57, 349/58, 349/62, 349/64, 349/65, 349/86, 349/77, 349/96
• US Class Current: 349/5
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133538 with spatial distribution of the polarisation direction
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133627 Projection-direct viewing
• CPC Class Codes: G03B 21/132 Overhead projectors, i.e. capable of projecting hand-writing or drawing during action epidiascopic projectors G03B21/08
• CPC Class Codes: G03B 21/30 adapted to collapse or fold, e.g. for portability
• CPC Class Codes: G06F 1/1616 with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/1639 the display being based on projection
• CPC Class Codes: G06F 1/1645 the display being suitable to be used in combination with an external overhead projector
• CPC Class Codes: G06F 1/1654 the display being detachable, e.g. for remote use
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/045 : using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: H04N 13/133 : Equalising the characteristics of different image components, e.g. their average brightness or colour balance
• CPC Class Codes: H04N 13/15 : for colour aspects of image signals
• CPC Class Codes: H04N 13/156 : Mixing image signals
• CPC Class Codes: H04N 13/161 : Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/167 : Synchronising or controlling image signals
• CPC Class Codes: H04N 13/189 : Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/194 : Transmission of image signals
• CPC Class Codes: H04N 13/204 : using stereoscopic image cameras stereoscopic photography G03B35/00
• CPC Class Codes: H04N 13/218 : using spatial multiplexing
• CPC Class Codes: H04N 13/239 : using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/243 : using three or more 2D image sensors
• CPC Class Codes: H04N 13/246 : Calibration of cameras
• CPC Class Codes: H04N 13/257 : Colour aspects
• CPC Class Codes: H04N 13/275 : from 3D object models, e.g. computer-generated stereoscopic image signals
• CPC Class Codes: H04N 13/279 : the virtual viewpoint locations being selected by the viewers or determined by tracking
• CPC Class Codes: H04N 13/286 : having separate monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/289 : Switching between monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/296 : Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 13/324 : Colour aspects
• CPC Class Codes: H04N 13/327 : Calibration thereof
• CPC Class Codes: H04N 13/334 : using spectral multiplexing
• CPC Class Codes: H04N 13/337 : using polarisation multiplexing
• CPC Class Codes: H04N 13/341 : using temporal multiplexing
• CPC Class Codes: H04N 13/344 : with head-mounted left-right displays
• CPC Class Codes: H04N 13/359 : Switching between monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/361 : Reproducing mixed stereoscopic images; Reproducing mixed monoscopic and stereoscopic images, e.g. a stereoscopic image overlay window on a monoscopic image background
• CPC Class Codes: H04N 13/363 : using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 13/368 : for two or more viewers
• CPC Class Codes: H04N 13/373 : for tracking forward-backward translational head movements, i.e. longitudinal movements
• CPC Class Codes: H04N 13/376 : for tracking left-right translational head movements, i.e. lateral movements
• CPC Class Codes: H04N 13/38 : for tracking vertical translational head movements
• CPC Class Codes: H04N 13/383 : for tracking with gaze detection, i.e. detecting the lines of sight of the viewer's eyes
• CPC Class Codes: H04N 13/398 : Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 19/597 : specially adapted for multi-view video sequence encoding
• CPC Class Codes: H04N 5/7441 : the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 5/7491 : of head mounted projectors
• CPC Class Codes: H04N 9/3141 : Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

An electro-optical backlighting panel construction for use in portable computer-based systems having direct and projection viewing modes of operation. In the illustrative embodiments of the present invention, the electro-optical backlighting panel is integrated with a LCD display panel, a micropolarization panel, and a touch-screen writing panel to provide several different types of portable computer-based systems including, for example, a portable notebook computer, a computer-driven image display device, and a portable pen-computing device. In general, each of these computer-based systems are capable of selectively displaying color video images on an actively driven display surface, or projecting such video images onto a wall surface or projection screen. These computer-based systems can be easily reconfigured for projection viewing without any sort of physical modification to the LCD display panel assembly. If desired, the these computer-based systems can be used to directly view "spatially-multiplexed" images of 3-D objects or imagery during the direct viewing mode, and when desired these spatially-multiplexed images can be projected onto a wall surface or projection screen during the projection viewing mode. When the spatially-multiplexed images are viewed through electrically-passive polarized glasses, the 3-D object is perceived with stereoscopic depth sensation in either mode of viewing. A portable light projection accessory device is provided for use with the portable computer-based systems of the present invention. In the illustrative embodiments, the portable light projection device has first and second housing portions that are interconnected by a foldable structure that permits the first and second housing portions to be selectively reconfigured for simple trouble-free use during the projection viewing mode of operation, and for compact storage during the direct viewing mode of operation.

Claims

1. An image display device having direct and projection viewing modes of operation, said image display device comprising:

light producing means for producing light during said direct viewing mode;

a light guiding structure formed from optically transparent material, said light guiding structure having first and second light guiding surfaces, and a first light conducting edge through which light produced from said light producing means can be transmitted into said light guiding structure and undergo total internal reflection between said first and second light guiding surfaces;

a light diffusing structure operably associated with said light guiding structure, said light diffusing structure having a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode;

a spatial light mask, disposed adjacent said light diffusing structure, being optically transparent during said projection viewing mode, and having means for modulating the spatially intensity of light transmitted through said light diffusing structure; and

state selection means for selecting said light scattering state of operation for said light diffusing structure during said direct viewing mode, and for selecting said light non-scattering state of operation for said light diffusing structure during said projection viewing mode,

wherein during said direct viewing mode, said light diffusing structure scatters light reflected within said light guiding structure and a portion of said scattered light is transmitted through said second light guiding surface of said light guiding structure and said light diffusing structure, and through said spatial light mask, and

wherein during said projection viewing mode, said light diffusing structure permits light produced from an external source to be transmitted through the first and second light guiding surfaces of said light guiding structure and said light diffusing structure without substantial scattering, and through said spatial light mask, for spatial intensity modulation of said transmitted light.

2. The image display device of claim 1, which further comprises a light reflective surface removably positionable at a distance from said second light guiding surface of said light guiding structure.

3. The image display device of claim 1, wherein said light diffusing structure comprises a polymer-dispersed liquid crystal panel having optically transparent electrode surfaces.

4. The image display device of claim 1, wherein said spatial light mask comprises a display surface for displaying a composite pixel pattern representative of a spatially multiplexed image composed of first and second spatially modulated perspective images of a 3-D object, said first spatially modulated perspective image consisting of a first pixel pattern representative of a first perspective image of said 3-D object spatially modulated according to a first spatial modulation pattern, said second spatially modulated perspective image consisting of a second pixel pattern representative of a second perspective image of said 3-D object spatially modulated according to a second spatial modulation pattern, said second spatial modulation pattern being a logical complement of said first spatial modulation pattern, and

wherein said image display device further comprises a micropolarization panel comprising a optically transparent sheet directly mounted onto said display surface of said spatial light mask, said optically transparent sheet having first and second optically transparent patterns permanently formed in said optically transparent sheet, said first optically transparent pattern spatially corresponding to and being spatially aligned with said first pixel pattern so as to impart a first polarization state P1 to light emanating from said first pixel pattern, and said second optically transparent pattern spatially corresponding to and being spatially aligned with said second pixel pattern so as to impart a second polarization state P2 to light emanating from said second pixel pattern, said second polarization state P2 being different than said first polarization state P1.

5. The image display device of claim 4, wherein said spatial light mask is electrically programmable.

6. The image display device of claim 1, wherein said spatial light mask is electrically programmable, and said light diffusing structure comprises:

a first electro-optical light diffusing panel having first and second light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said first light transmission surface being in direct physical contact with said second light guiding surface of said light guiding structure;

a second electro-optical light diffusing panel having third and fourth light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said third light transmission surface of said second electro-optical light diffusing panel being physically spaced apart from said second light transmission surface of said first electro-optical light diffusing panel, by a first ultra-thin air gap, and said fourth light transmission surface of said second electro-optical light diffusing panel being adjacent said spatial light mask; and

a third electro-optical light diffusing panel having fifth and sixth light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said sixth light transmission surface of said third electro-optical light diffusing panel being physically spaced apart from said first light guiding surface of said light guiding structure, by a second ultra-thin air gap.

7. The image display device of claim 6, which further comprises a light reflective surface removably positionable adjacent said fifth light transmission surface of said third electro-optical light diffusing panel.

8. The image display device of claim 6, which further comprises a Fresnel lens structure physically affixed to said third electro-optical light diffusing panel.

9. The image display device of claim 6,

wherein said spatial light mask is electrically programmable;

wherein said first electro-optical light diffusing panel is a first electrically-controlled polymer-dispersed liquid crystal panel having a first pair of optically transparent electrode surfaces across which a first electric field is applied under the control of said state selection means;

wherein said second electro-optical light diffusing panel is a second electrically-controlled polymer-dispersed liquid crystal panel having a second pair of optically transparent electrode surfaces across which a second electric field is applied under the control of said state selection means; and

wherein said third electro-optical light diffusing panel is a third electrically-controlled polymer-dispersed liquid crystal panel having a third pair of optically transparent electrode surfaces across which a third electric field is applied under the control of said state selection means.

10. The image display device of claim 9, which further comprises a display control means for controlling the spatial intensity of light emanating from said electrically programmable spatial light mask, and

wherein said electrically programmable spatial light mask comprises a liquid crystal display panel comprising an array of electrically addressable pixels, each said pixel having a light transmittance that is controllable by said display control means.

11. The image display device of claim 9,

wherein said first electrically-controlled polymer-dispersed liquid crystal panel contains a patterned distribution of liquid crystal molecules which in response to said first electric field selectively scatters light along said second light guiding surface of said light guiding structure;

wherein said second electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said second electric field selectively scatters light within said second electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emerges therefrom in the direction of said electrically programmable spatial light mask; and

wherein said third electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said third electric field selectively scatters light within said third electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emanates therefrom in the direction of said light guiding structure.

12. The image display device of claim 9,

wherein said first electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules, and said first optically transparent electrode surface includes first and second sets of interleaved electrode strips extending substantially parallel to each other, and said first electric field is applied across only said first set of electrode strips and said second electrode layer during said direct viewing mode so that the liquid crystal molecules beneath said second set of electrode strips are randomly oriented and scatter light during said direct viewing mode, and

wherein said first electric field is applied across both said first and second sets of interleaved electrode strips and said second electrode layer during said projection viewing mode so that the liquid crystal molecules beneath said first and second sets of interleaved electrode strips are substantially aligned with said first electric field to permit light to pass through said first electrically-controlled polymer-dispersed liquid crystal panel without substantial scattering during said projection viewing mode;

wherein said second electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said second electric field selectively scatters light within said second electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emanates therefrom in the direction of said electrically programmable spatial light mask; and

wherein said third electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said third electric field selectively scatters light within said third electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emanates therefrom in the direction of said light guiding structure.

13. The image display device of claim 1, wherein said light guiding structure is made from an optically transparent panel.

14. The image display device of claim 1, wherein said light guiding structure comprises first and second light conducting edges, and wherein said light producing means comprises first and second fluorescent tubes disposed along said first and second light conducting edges, respectively, said first and second fluorescent tubes producing and transmitting light through said first and second light conducting edges during said direct viewing mode.

15. The image display device of claim 14, which further comprises first and second light focusing elements disposed in proximity with said first and second fluorescent tubes, respectively, for focusing light produced from said first and second fluorescent tubes and directing said focused light across said first and second light conducting edges and into said light guiding structure.

16. The image display device of claim 1, which further comprises a Fresnel lens structure adjacent said light guiding structure.

17. The image display device of claim 16, wherein said Fresnel lens is affixed to said light diffusing structure.

18. The image display device of claim 16, in combination with a portable light projection device, wherein said portable light projection device comprises:

a first housing portion containing a light producing means for producing visible light, and a light focusing means for focusing and directing said produced visible light through said display panel assembly for optical processing and conversion into an image on the display surface of said spatial light mask; and

a second housing portion having an image projecting lens for projecting onto a viewing surface, the image displayed on the display surface of said display panel assembly.

19. The image display device of claim 18, which further comprises a light polarizing filter disposed in said first housing portion, for imparting a selected polarization state to visible light transmitted through said display panel assembly.

20. The image display device of claim 19, which further comprises a portable housing having a light transmission aperture though which said unitary display panel assembly is supported.

21. The image display device of claim 1, wherein said light producing means, said light guiding structure and said light diffusing structure form a unitary display panel assembly.

22. The image display device of claim 1, which further comprises an optically transparent touch-screen panel disposed adjacent said spatial light mask.

23. The image display device of claim 1, which further comprises a thin light focusing panel adjacent said light guiding structure.

24. The image display device of claim 4, in combination with polarization glasses.

25. The image display device of claim 24, which further comprises an optically transparent touch-screen panel adjacent said spatial light mask.

26. A portable computer-based system having direct and projection viewing modes of operation, comprising:

a housing of compact construction;

data storage means, disposed in said housing, for storing data representative of one or more images; and

a display panel assembly, supported within said housing,

said display panel assembly including

light producing means for producing light during said direct viewing mode,

a light guiding structure having first and second light guiding surfaces between which said produced light can be totally internally reflected during said direct viewing mode,

a light diffusing structure operably associated with said light guiding structure, said light diffusing structure having a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode,

a programmable spatial light mask, disposed in direct physical contact with said light diffusing structure, being optically transparent during said projection viewing mode, and including means for modulating the spatial intensity of light transmitted from said light diffusing structure and through said programmable spatial light mask, and

state selection means for selecting said light scattering state of operation for said light diffusing structure during said direct viewing mode, and for selecting said light non-scattering state of operation for said light diffusing structure during said projection viewing mode,

wherein during said light scattering state of operation, said light diffusing structure scatters light reflected within said light guiding structure and a portion of said scattered light is transmitted through said second light guiding surface of said light guiding structure and said light diffusing structure, and through said programmable spatial light mask, and

wherein during said projection viewing mode, said light diffusing structure permits light produced from an external source to be transmitted through the first and second light guiding surfaces of said light guiding structure and said light diffusing structure without substantial scattering, and through said programmable spatial light mask, for spatial intensity modulation of said transmitted light.

27. The portable computer-based system of claim 26, wherein said light guiding structure further comprises a first light conducting edge through which light produced from said light producing means can be transmitted into said light guiding structure for total internal reflection between said first and second light guiding surfaces.

28. The portable computer-based system of claim 26, wherein said display panel assembly is in the form of a unitary structure.

29. The portable computer-based system of claim 26, which further comprises a light reflective surface removably positionable at a distance from said first light guiding surface of said light guiding structure.

30. The portable computer-based system of claim 26, wherein said light diffusing structure comprises a polymer-dispersed liquid crystal panel having optically transparent electrode surfaces.

31. The portable computer-based system of claim 26, wherein said programmable spatial light mask includes a display surface for displaying a composite pixel pattern representative of a spatially multiplexed image composed of first and second spatially modulated perspective images of a 3-D object, said first spatially modulated perspective image consisting of a first pixel pattern representative of a first perspective image of said 3-D object spatially modulated according to a first spatial modulation pattern, said second spatially modulated perspective image consisting of a second pixel pattern representative of a second perspective image of said 3-D object spatially modulated according to a second spatial modulation pattern, said second spatial modulation pattern being a logical complement of said first spatial modulation pattern, and

wherein said display panel assembly further comprises a micropolarization panel comprising an optically transparent sheet mounted onto said display surface of said programmable spatial light mask, said optically transparent sheet having first and second optically transparent patterns permanently formed in said optically transparent sheet, said first optically transparent pattern spatially corresponding to and being spatially aligned with said first pixel pattern so as to impart a first polarization state P1 to light emanating from said first pixel pattern, and said second optically transparent pattern spatially corresponding to and being spatially aligned with said second pixel pattern so as to impart a second polarization state P2 to light emanating from said second pixel pattern, said second polarization state P2 being different than said first polarization state P1.

32. The portable computer-based system of claim 26, wherein said light diffusing structure comprises:

a first electro-optical light diffusing panel having first and second light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said first light transmission surface being in direct physical contact with said second light guiding surface of said light guiding structure;

a second electro-optical light diffusing panel having third and fourth light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said third light transmission surface of said second electro-optical light diffusing panel being physically spaced apart from said second light transmission surface of said first electro-optical light diffusing panel, by a first ultra-thin air gap, and said fourth light transmission surface of said second electro-optical light diffusing panel being adjacent said programmable spatial light mask; and

a third electro-optical light diffusing panel having fifth and sixth light transmission surfaces and a light scattering state of operation selectable during said direct viewing mode, and a light non-scattering state of operation selectable during said projection viewing mode, said sixth light transmission surface of said third electro-optical light diffusing panel being physically spaced apart from said first light guiding surface of said light guiding structure, by a second ultra-thin air gap.

33. The portable computer-based system of claim 32, which further comprises a light reflective surface removably positionable against said third electro-optical light diffusing structure.

34. The portable computer-based system of claim 32, wherein said display panel assembly further comprises a thin lens panel mounted to said third electro-optical light diffusing panel.

35. The portable computer-based system of claim 32,

wherein said first electro-optical light diffusing panel is a first electrically-controlled polymer-dispersed liquid crystal panel having a first pair of optically transparent electrode surfaces across which a first electric field is applied under the control of said state selection means;

wherein said second electro-optical light diffusing panel is a second electrically-controlled polymer-dispersed liquid crystal panel having a second pair of optically transparent electrode surfaces across which a second electric field is applied under the control of said state selection means; and

wherein said third electro-optical light diffusing panel is a third electrically-controlled polymer-dispersed liquid crystal panel having a third pair of optically transparent electrode surfaces across which a third electric field is applied under the control of said state selection means.

36. The portable computer-based system of claim 26, which further comprises a display control means for controlling the spatial intensity of light emerging from said programmable spatial light mask, and

wherein said programmable spatial light mask comprises a liquid crystal display panel comprising an array of electrically addressable pixels, each said pixel having a light transmittance controllable by said display control means.

37. The portable computer-based system of claim 35,

wherein said first electrically-controlled polymer-dispersed liquid crystal panel contains a patterned distribution of liquid crystal molecules which in response to said first electric field selectively scatters light along said second light guiding surface of said light guiding structure;

wherein said second electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said second electric field selectively scatters light within said second electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emerges therefrom in the direction of said programmable spatial light mask; and

wherein said third electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said third electric field selectively scatters light within said third electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emerges therefrom in the direction of said light guiding structure.

38. The portable computer-based system of claim 35, wherein said first electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules, and

wherein said first optically transparent electrode surface includes first and second sets of interleaved electrode strips extending substantially parallel to each other, and said first electrical field is applied across only said first set of electrode strips and said second electrode layer during said direct viewing mode so that the liquid crystal molecules beneath said second set of electrode strips are randomly oriented and scatter light during said direct viewing mode, and

wherein said first electrical field is applied across both said first and second sets of interleaved electrode strips and said second electrode layer during said projection viewing mode so that the liquid crystal molecules beneath said first and second sets of interleaved electrode strips are substantially aligned with said first electrical field to permit light to pass through said first electrically-controlled polymer-dispersed liquid crystal panel without substantial scattering during said projection viewing mode;

wherein said second electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said second electric field selectively scatters light within said second electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emanates therefrom in the direction of said programmable spatial light mask; and

wherein said third electrically-controlled polymer-dispersed liquid crystal panel contains a substantially uniform distribution of liquid crystal molecules which in response to said third electric field selectively scatters light within said third electrically-controlled polymer-dispersed liquid crystal panel so that a substantially uniform light intensity distribution emanates therefrom in the direction of said light guiding structure.

39. The portable computer-based system of claim 26, wherein said light guiding structure is made from an optically transparent plastic.

40. The portable computer-based system of claim 32, wherein said light guiding structure comprises first and second light conducting edges, and wherein said light producing means comprises first and second fluorescent tubes disposed along said first and second light conducting edges, respectively, said first and second fluorescent tubes producing and transmitting light through said first and second light conducting edges during said direct viewing mode.

41. The portable computer-based system of claim 40, wherein said electro-optical display panel assembly further comprises first and second light focusing elements disposed in proximity with said first and second fluorescent tubes, respectively, for focusing light produced from said first and second fluorescent tubes and directing said focused light across said first and second light conducting edges and into said light guiding structure.