Active matrix LCD image projection system

• US 5,012,274 A
• Filed: 12/23/1988
• Issued: 04/30/1991
• Est. Priority Date: 12/31/1987
• Status: Expired due to Fees

• Current Assignee: Projectavision, Inc. (Vidikron Technologies Group, Inc.)
• Original Assignee: Projectavision, Inc. (Vidikron Technologies Group, Inc.)
• Inventors: Dolgoff, Eugene
• Primary Examiner(s): Brier, Jeffrey A.
• Application Number:
  US07/290,040
• Time in Patent Office: 858 Days
• Field of Search: 340/795, 340/705, 340/784, 340/765, 340/702, 340/703, 340/796, 340/815.17, 340/815.31, 358/60, 358/61, 358/56, 358/231, 358/232, 358/236, 358/88, 358/89, 358/3, 350/331 R, 350/331 T, 350/334, 350/339 F, 350/339 R, 350/117, 350/128, 181/200, 181/201, 181/206, 181/211, 181/225, 353/31, 353/32, 353/33, 353/34, 353/84, 353/122
• US Class Current: 345/88
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: H04N 13/111 Transformation of image signals corresponding to virtual viewpoints, e.g. spatial image interpolation
• 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 13/239 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 13/261 with monoscopic-to-stereoscopic image conversion
• CPC Class Codes: H04N 13/286 having separate monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/305 using lenticular lenses, e.g. arrangements of cylindrical lenses
• CPC Class Codes: H04N 13/31 using parallax barriers
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator
• CPC Class Codes: H04N 9/3197 using light modulating optical valves

Abstract

An active matrix LCD light valve between crossed polarizers, utilizing individual transistors to control each "pixel area" of the LCD and storage elements to store signal data for each pixel, with optically shielded "dead spaces" between pixels to eliminate electric field crosstalk and non-information-bearing light bleed through, is illuminated with a bright independent light source which creates a video image projected via specialized projection optics onto an internal or external screen without distortions, regardless of the angle of projection onto the screen. Use of heat sinks, IR reflective coatings, heat absorbing optics, optional fluid, and a thermistor controlled pixel transistor bias voltage injection servo circuit stabilizes image performance, maintaining accurate color and contrast levels as the LCD changes temperature. In one embodiment of the invention, use of a multi-color LCD with a stepped cavity, producing different thicknesses of LCD for the different wavelengths that pass through it, allows a linear correspondence between the wavelengths passing through the LCD to produce true black, high contrast, and CRT-like color rendition. A dichroic mirror arrangement is used to overlap differently colored pixels and a striped mirror system is used to duplicate and offset the resulting "full color" pixels or a lens system is used to expand existing pixels to fill the "dead spaces" between pixels in the projected image, creating a continuous image with no apparent stripes or dots. A special venetian-blind type of screen is also disclosed and methods for using the system to view three dimensional video are also explained.

Claims

1. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming an image;

a solid state storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state storage elements for controlling the operation thereof, said control means, storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces;

means for maintaining color registration of pixel images; and

means for directly projecting the image formed by said LCD onto a viewing area while maintaining color registration such that registered pixel images are caused to eliminate dead spaces between pixels.

2. The video display system of claim 1 wherein said control means associated with each pixel includes a transistor, said transistor when turned on by a gate signal, conducts a voltage of a specific value associated with the desired brightness at its respective pixel.

3. The video display system of claim 2, wherein said transistor includes a field effect transistor.

4. The video display system of claim 1, wherein substantially no light emanates from said dead spaces.

5. The video display system of claim 4, further comprising a light-blocking covering positioned between pixels.

6. The video display system of claim 1, further comprising a heat sink adapted to dissipate heat energy from said projecting means and/or said active matrix.

7. The video display system of claim 1, wherein said projection means includes lens elements coated for heat reflection.

8. The video display system of claim 1, further comprising heat absorbing elements adapted to dissipate heat energy from said projecting means and/or said active matrix.

9. The video display system of claim 1, further comprising a fluid means adapted to dissipate heat energy from said projecting means and/or said active matrix.

10. The video display system of claim 1, wherein said projecting means further comprises reflective optics constructed of a metalic substance.

11. The video display system of claim 1, further comprising;

a heat sensing device for sensing heat in proximity to the active matrix, wherein said device monitors temperature and biases the active matrix LCD to counter temperature fluctuation effects.

12. The video display system of claim 1, further comprising a plurality of LCDs to project multiple images onto the viewing area to produce a black and white or colored image.

13. The video display system of claim 1, further comprising dichroic optics, wherein said dichroic optics overlap differently colored LCD projected images permitting said images to be focused onto a screen with a single projection lens system.

14. The video display system of claim 4, further comprising a mirror system to duplicate the image of the pixels into the dead spaces between pixels.

15. The video display system of claim 4, further comprising lenses to fill the dead spaces between pixels.

16. The video display system of claim 15, wherein said lenses are arranged in a lens array.

17. The video display system of claim 16, wherein said lens array is lenticular.

18. The video display system of claim 1, wherein said LCD is a full-color LCD, comprising pixels of a plurality of colors.

19. The video display system of claim 18, wherein light emanating from one of the colored pixels overlaps light emanating from another colored pixel.

20. The video display system of claim 19, wherein substantially no light emanates from said dead spaces.

21. The video display system of claim 20, wherein said image is replicated to fill the dead spaces between pixels.

22. The video display system of claim 20, wherein light emanating from each of the plurality of colored pixels is optically expanded, individually, to fill the dead spaces between pixels.

23. The video display system of claim 1, further comprising:

a liquid crystal container, wherein said container is stepped to produce different cavity lengths of liquid crystal corresponding to different wavelengths of light to be projected through different areas of the liquid crystal display.

24. The video display system of claim 1, further comprising means for projecting the image onto a ceiling.

25. The video display system of claim 1, wherein said viewing area comprises a venetian blind type of screen comprising a plurality of rotatable slats wherein such slats are substantially rigid and mechanically rotatable.

26. The video display system of claim 1, further comprising a projection lens system, wherein said lens system trapezoidally pre-distorts the image to compensate for keystone distortion resulting from projection of the image onto a surface such that the surface is not normal to a line joining the surface and the projection lens.

27. The video display system of claim 1, wherein said system projects onto a surface which is not normal to a line joining the surface and the projection optics, wherein the LCD and projection optics are tilted so that their planes intersect at a line which also intersects the plane of the surface being projected upon.

28. The video display system of claim 1, further comprising a plurality of projection means, wherein the projection means project polarized stereoscopically-related images onto a non-depolarizing screen to be viewed in 3-D.

29. The video display system of claim 28, wherein said stereoscopically related images are optically integrated before being further projected by a single projection lens system onto a screen.

30. The video display system of claim 1, further comprising a plurality of projection means, wherein said projection means project images emanating therefrom onto a screen comprising two lenticular lenses positioned back to back, restricting angle of view of each image.

31. The video display system of claim 1, further comprising a sound suppression system for eliminating cooling system noise.

32. The video display system of claim 31, wherein said sound suppression system comprises sound absorbing material.

33. The video display system of claim 31, wherein said sound suppression system further comprises barriers to deflect sound.

34. The video display system of claim 31, wherein said sound suppression system further comprises:

a microphone;

a speaker; and

a circuit to alter phase of a sound signal detected by the microphone before sending it to the speaker.

35. The video display system of claim 1, wherein the viewing area has a surface which is textured to reduce glare.

36. The video display system of claim 1, wherein said viewing area is darkly colored.

37. The video display system of claim 1, wherein electronic signals relating to formation of the image are digitized.

38. The video display system of claim 1, wherein high resolution data is used for the display of a high resolution image.

39. The video display system of claim 1, wherein the image enters one of two ends of a coherent fiber-optic bundle and is subsequently viewed at the other end of the fiber-optic bundle.

40. The video display systems of claim 39, wherein lenses magnify the image emanating from the fiber-optic bundle before it is viewed.

41. The video display system of claim 1, wherein the means for projecting further comprises a means to expand the pixel images to eliminate said dead space.

42. The video display system of claim 1, wherein the means for projecting duplicates all or part of the pixel images to eliminate said dead space.

43. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming a black and white image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that pixel images are caused to eliminate dead spaces between pixels.

44. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming an image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that all or part of pixel image are duplicated and caused to eliminate dead spaces between pixels.

45. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming an image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that dead spaces between pixels are substantially eliminated.

46. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming an image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that pixel images are expanded and caused to eliminate dead spaces between pixels.

47. A video display system, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming a black and white image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that all or part of pixel images are duplicated and caused to eliminate dead spaces between pixels.

48. A video display, comprising:

a liquid crystal display (LCD) device having a plurality of pixels arranged in a matrix for forming a black and white image;

a solid state pixel storage element associated with each pixel for storing a respective pixel control signal;

control means associated with said solid state pixel storage elements for controlling the operation thereof, said control means, pixel storage elements and LCD forming an active matrix LCD, said active matrix including dead spaces; and

means for projecting the image formed by said LCD onto a viewing area such that all or part of said pixels are expanded to eliminate dead spaces between said pixels.