High efficiency light valve projection system

• US 5,900,982 A
• Filed: 11/03/1997
• Issued: 05/04/1999
• 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, Christie, Paul B., MacFarlane, Malcolm
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Juba, Jr., John
• Application Number:
  US08/963,016
• Time in Patent Office: 547 Days
• Field of Search: 359/487, 359/495, 359/496, 359/619, 359/622, 359/625, 359/627, 359/741, 349/5, 349/57, 349/62, 349/95, 345/84, 345/87, 362/299, 353/81, 353/98, 353/99, 353/102
• US Class Current: 359/619
• 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 5/7441 the modulator being an array of liquid crystal cells
• 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 9/3144 Cooling systems cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28
• CPC Class Codes: H04N 9/317 Convergence or focusing systems electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53
• CPC Class Codes: H04N 9/3188 Scale or resolution adjustment scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391

Abstract

A light valve such as an active matrix LCD between crossed polarizers, utilizing, for instance, individual transistors to control each "pixel area" of the LCD and storage elements to store video signal data for each pixel, with optically shielded "dead spaces" between pixels to eliminate electric field cross-talk 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 in the projected image. Use of striped mirrors duplicate pixels, where necessary, eliminating spaces between pixels, 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 display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced vertically and horizontally from a pixel hole directly in line with said each lens element.

2. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced vertically by one pixel and horizontally by one and a half pixels from a pixel hole directly in line with a said each lens element.

3. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced horizontally by two pixels from a pixel hole directly in line with said each lens element.

4. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced vertically by two pixels from a pixel hole directly in line with said each lens element.

5. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced vertically by two pixels and horizontally by three pixels from a pixel hole directly in line with a said each lens element.

6. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said-image-forming element for increasing collimation of light illuminating said image-forming element by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element; and

at least one input lens array located between said light folding means and having a plurality of lens elements for focusing the folded light into pixel holes of said image forming element;

wherein said light folding means folds the light at angles such that each lens element of said plurality of lens elements focuses light into a pixel hole which is displaced vertically by one pixel and horizontally by one-half pixel from a pixel hole directly in line with said each lens element.

7. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said image-forming element for increasing collimation of light illuminating said image-forming element, said collimation increasing means comprising means for utilizing non-well collimated light by redirecting it toward the image-forming element at one of a multiplicity of acceptance angles; and

at least one input lens array located between said collimation increasing means and said image-forming element for focusing the collimated light and the redirected non-well collimated light into the pixel holes of said image forming element;

wherein said collimation increasing means increases the collimation of light by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light which otherwise would miss said image-forming element,

and wherein said at least one input lens array comprises a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element, and

wherein said plurality of lens elements comprises a plurality of prisms.

8. The display system of claim 7, wherein said collimation increasing means increases the diameter of the light beam to an extent such that an angle of divergence of the light emerging from said collimation increasing means is close to an acceptable angle of said lens elements.

9. The display system of claim 8, wherein each lens element focuses light into a pixel hole other than a pixel hole in line with a corresponding lens element.

10. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said image-forming element for increasing collimation of light illuminating said image-forming element, said collimation increasing means comprising means for utilizing non-well collimated light by redirecting it toward the image-forming element at one of a multiplicity of acceptance angles; and

at least one input lens array located between said collimation increasing means and said image-forming element for focusing the collimated light and the redirected and non-well collimated light into the pixel holes of said image-forming element;

wherein said collimation increasing means increases the collimation of light by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light, which otherwise would miss said image-forming element,

wherein said at least one input lens array comprises a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element, and

wherein said display system further comprises an elliptical reflector for collecting light from said light source.

11. The display system of claim 10, further comprising means for reflecting light at an angle to an axis of said elliptical reflector before light is directed toward said image-forming element.

12. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said image-forming element for increasing collimation of light illuminating said image-forming element, said collimation increasing means comprising means for utilizing non-well collimated light by redirecting it toward the image-forming element at one of a multiplicity of acceptance angles; and

at least one input lens array located between said collimation increasing means and said image-forming element for focusing the collimated light and the redirected, non-well collimated light into the pixel holes of said image-forming element;

wherein said collimation increasing means increases the collimation of light by increasing diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light which otherwise would miss said image-forming element,

wherein said at least one input lens array comprises a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element, and

wherein said display system further comprises at least one additional light source for illuminating said image-forming element.

13. The display system of claim 12, further comprising a collimating lens located adjacent to said image-forming element.

14. A display system, comprising:

an element for forming an image thereon and having a plurality of pixel holes;

a light source for illuminating said image-forming element;

means located between said light source and said image-forming element for increasing collimation of light illuminating said image-forming element, said collimation increasing means comprising means for utilizing non-well collimated light by redirecting it toward the image-forming element at one of a multiplicity of acceptance angles; and

at least one input lens array located between said collimation increasing means and said image-forming element for focusing the collimating light and the redirected non-well collimated light into the pixel holes of said image-forming element;

wherein said collimation increasing means increases the collimation of light by increasing a diameter of a light beam radiated from said light source so that the light beam diameter becomes larger than said image-forming element, said collimation increasing means comprising means for folding light which otherwise would miss said image-forming element,

wherein said at least one input lens array comprises a plurality of lens elements for focusing the folded light into pixel holes of said image-forming element, and

wherein said display system further comprises light deflectors located between said light source and said image-forming element for deflecting light that misses said image forming element for passing through the pixel holes therein.

15. The display system of claim 14, wherein said light deflectors surround a light beam directly illuminating said image-forming element.