Electrically addressable liquid crystal projection system with high efficiency and light output

• US 5,115,305 A
• Filed: 07/05/1990
• Issued: 05/19/1992
• Est. Priority Date: 07/05/1990
• Status: Expired due to Fees

• Current Assignee: TR Technologies Incorporated
• Original Assignee: TR Technologies Incorporated
• Inventors: Baur, Thomas G., Badertscher, Roger H.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): VU, KIM Y
• Application Number:
  US07/549,594
• Time in Patent Office: 684 Days
• Field of Search: 358/60, 358/61, 350/376, 350/379, 350/337, 350/338, 350/331 R, 353/31, 353/34, 359/73, 359/40, 359/41
• US Class Current: 348/751
• 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

Abstract

An improved polarized color video projector incorporates a light source to provide three collimated beams of linearly polarized light of blue, green, and red colors. A light modulator capable of imparting a video image in a light beam is positioned in each of the three colored beams to modulate the individual colored image components in each of the beams. A dischroic beam recombiner receives the modulated blue and green beams, and recombines them into a combined blue and green color image carrying beam. A polarization-selective/beam analyzer/recombiner receives the recombined blue and green beam and recombines it with the red beam. A retarder placed between the light modulator for the red beam and the polarization-selective/beam analyzer/recombiner, in the path of the modulated red beam, rotates the plane of polarization of the red beam to allow it to be recombined with the recombined blue and green beam in the polarization-selective/beam analyzer/recombiner. Projection apparatus receives the recombined blue, green, and red beams and projects them onto a display screen.

Claims

1. Color video projector apparatus, comprising a structural geometry oriented in a manner that describes nine positionally related component planes, including:

first, second, and third planes positioned substantially parallel to each other and with adjacent ones of those first, second, and third planes positioned approximately equidistant apart;

fourth, fifth, and sixth planes positioned substantially parallel to each other and perpendicularly intersecting said first, second, and third planes, adjacent ones of said fourth, fifth, and sixth planes being positioned approximately the same distance apart as the distance between adjacent ones of said first, second, and third planes;

a seventh plane positioned to intersect said first and second planes where said first and second planes intersect said fifth and sixth planes, respectively;

an eighth plane positioned to intersect said first, second, and third planes where said first, second, and third planes intersect said fourth, fifth, and sixth planes, respectively; and

a ninth plane positioned to intersect said second and third planes where said second and third planes intersect said fifth and sixth planes, respectively, such that said seventh, eighth, and ninth planes are parallel to each other and are oriented at substantially 45-degree angles to said first, second, and third planes as well as to said fourth, fifth, and sixth planes;

first transmissive light valve means with an incident surface positioned in said third plane between said fourth and fifth planes for modulating a first color light beam being transmitted therethrough;

second transmissive light valve means with an incident surface positioned in said fifth plane between said second and third planes for modulating a second color light beam being transmitted therethrough;

third transmissive light valve means with an incident surface positioned in said second plane between said fifth and sixth planes for modulating a third color light beam being transmitted therethrough;

first color light source means for creating said first color light beam and directing it to the incident surface of said first transmissive light valve means;

second color light source means for creating said second color light beam and directing it to the incident surface of said second transmissive light valve means;

third color light source means for creating said third color light beam and directing it to the incident surface of said third transmissive light valve means;

first beam combining means positioned in said ninth plane between said second and third planes for combining said first color light beam emerging from said first transmissive light valve means with said second color light beam emerging from said second transmissive light valve means to create a combined first and second colors light beam directed between and substantially parallel to said fourth and fifth planes;

second beam combining means positioned in said eighth plane between said fourth and fifth planes for combining said third color light beam emerging from said third transmissive light valve means with said combined first and second colors light beam to create a first, second, and third colors light beam; and

first light redirecting means positioned in said seventh plane between said fifth and sixth planes for redirecting said third color light beam into said second beam combining means.

2. The color video projector apparatus of claim 1, wherein said first color light source means, said second color light source means, and said third color light source means create said first color light beam, said second color light beam, and said third color light beam polarized in a first plane of polarization, and said first transmissive light valve means, said second transmissive light valve means, and said third transmissive light valve means modulate said first color light beam, said second color light beam, and said third color light beam, respectively, by rotating selected pixel portions of said respective first color light beam, said second color light beam, and said third color light beam toward a second plane of polarization.

3. The color video apparatus of claim 2, wherein said first beam recombining means includes a dichroic mirror that transmits said first color light beam and reflects said second color light beam.

4. The color video apparatus of claim 3, wherein said second beam recombining means includes a polarization selective surface that either reflects or transmits light polarized in said first plane of polarization and, oppositely, either transmits or reflects light polarized in said second plane of polarization.

5. The color video apparatus of claim 4, including retarder means positioned in either the path of said combined first and second colors beam or said third color beam for effectively rotating the plane of polarization of one with respect to the other such that light in the first plane of polarization is effectively rotated to the second plane of polarization and vice versa.

6. The color video apparatus of claim 5, wherein said structural geometry also includes a tenth plane positioned substantially parallel to said third plane and spaced about the same distance apart from said third plane as said second plane is spaced from said third plane, but on the opposite side, and an eleventh plane positioned substantially parallel to said ninth plane and about the same distance from said ninth plane as said eighth plane is from said ninth plane, but on the opposite side, and wherein said first color light source means includes a first color dichroic mirror positioned in said ninth plane between said third and tenth planes, and second light redirecting means positioned in said eleventh plane between said fourth and fifth planes for redirecting said first color light beam to said first transmissive light valve means, and wherein said second color light source means includes a second color dichroic mirror positioned in said eighth plane between said second and third planes

7. The color video projector apparatus of claim 6, wherein said first color light source means, said second color light source means, and said third color light source means all comprise together a polarization selective surface positioned parallel to, and about midway between said ninth and eleventh planes and between said fifth and sixth planes, a spectral mirror in said eleventh plane adjacent said fifth plane, and a retarder between said polarization selective surface and said first color dichroic mirror, and a substantially white light source positioned adjacent said polarization selective surface.

8. The color video projector apparatus of claim 2, wherein said first light redirecting means includes a polarization selective surface that either reflects or transmits light polarized in said first plane of polarization and, oppositely, either transmits or reflects light polarized in said second plane of polarization.

9. The color video projector apparatus of claim 8, wherein said first beam recombining means includes a polarization selective surface that either reflects or transmits light polarized in said first plane of polarization and, oppositely, either transmits or reflects light polarized in said second plane of polarization.

10. The color video projector apparatus of claim 9, wherein said second beam recombining means includes a dichroic mirror that transmits said third color light beam and reflects said combined first and second colors light beam.

11. The color video apparatus of claim 10, including retarder means positioned in either the path of said first color light beam or said second color light beam for effectively rotating the plane of polarization of one with respect to the other such that light in the first plane of polarization is effectively rotated to the second plane of polarization and vice versa.

12. The color video apparatus of claim 11, wherein said structural geometry also includes a tenth plane positioned substantially parallel to said third plane and spaced about the same distance apart from said third plane as said second plane is spaced from said third plane, but on the opposite side, and an eleventh plane positioned substantially parallel to said ninth plane and about the same distance from said ninth plane as said eighth plane is from said ninth plane, but on the opposite side, and wherein said first color light source means includes a first color dichroic mirror positioned in said ninth plane between said third and tenth planes, and second light redirecting means positioned in said eleventh plane between said fourth and fifth planes for redirecting said first color light beam to said firs transmissive light valve means, and wherein said second color light source means includes a second color dichroic mirror positioned in said eighth plane between said second and third planes.

13. The color video projector apparatus of claim 12, wherein said first color light source means, said second color light source means, and said third color light source means all comprise together a polarization selective surface positioned parallel to, and about midway between said ninth and eleventh planes and between said fifth and sixth planes, a spectral mirror in said eleventh plane adjacent said fifth plane, and a retarder between said polarization selective surface and said spectral mirror, and a substantially white light source positioned adjacent said polarization selective surface.

14. The color video projector apparatus of claim 2, wherein said first and second beam recombining means includes a polarization selective surface that either reflects or transmits light polarized in said first plane of polarization and, oppositely, either transmits or reflects light polarized in said second plane of polarization.

15. The color video projector apparatus of claim 14, including multiwave retarder means positioned in the path o said combined first and second colors beam for reorienting the plane of polarization of one of the colored beams in said combined first and second colors beam with respect to the other one of the colored beams in said combined first and second colors beam such that light in the first plane of polarization is effectively rotated to the second plane of polarization and vice versa.

16. The color video projector apparatus of claim 15, including retarder means positioned in either the path of said first color light beam or said second color light beam for effectively rotating the plane of polarization of one with respect to the other such that light in the first plane of polarization is effectively rotated to the second plane of polarization and vice versa.

17. The color video apparatus of claim 16, wherein said structural geometry also includes a tenth plane positioned substantially parallel to said third plane and spaced about the same distance apart from said third plane as said second plane is spaced from said third plane, but on the opposite side, and an eleventh plane positioned substantially parallel to said ninth plane and about the same distance from said ninth plane as said eighth plane is from said ninth plane, but on the opposite side, and wherein said first color light source means includes a first color dichroic mirror positioned in said ninth plane between said third and tenth planes, and second light redirecting means positioned in said eleventh plane between said fourth and fifth planes for redirecting said first color light beam to said first transmissive light valve means, and wherein said second color light source means includes a second color dichroic mirror positioned in said eighth plane between said second and third planes.

18. The color video projector apparatus of claim 17, wherein said first color light source means, said second color light source means, and said third color light source means all comprise together a polarization selective surface positioned parallel to, and about midway between said ninth and eleventh planes and between said fifth and sixth planes, a spectral mirror in said eleventh plane adjacent said fifth plane, and a retarder between said polarization selective surface and said spectral mirror, and a substantially white light source positioned adjacent said polarization selective surface

19. The color video projector apparatus of claim 15, wherein said multiwave retarder retards said first color light in said recombined first and second color light beam by approximately an integer multiple of one wavelength plus one-half wavelength, such as 11/2, 21/2, 31/2, . . . , n1/2, to effectively reorient the plane of polarization of said first color light by about 90-degrees, and wherein said multiwave retarder retards said second color light in said recombined first and second color light beam by approximately an integer multiple of one wavelength, such as 1, 2, 3, . . . , n, to effectively leave the orientation of the plane of polarization of said second color light unchanged.

20. The method of projecting a color video image, comprising the steps of:

modulating a first color light beam having a first wavelength by changing selected pixel portions of said first color beam in such a manner that said first color beam carries a first color component of the color video image in a modulated first color beam that is linearly polarized in a first plane of polarization;

modulating a second color light beam having a second wavelength by changing selected pixel portions of said second color beam in such a manner that said second color beam carries a second color component of the color video image in a modulated second color beam that is also linearly polarized in said first plane of polarization;

combining said modulated first color beam with said second color beam in such a manner that they comprise a combined first and second colors image carrying beam propagated along a common path with said first and second color components linearly polarized in said first plane of polarization;

modulating a third color light beam by changing selected pixel portions of said third color beam in such a manner that said third color beam carries a third color component of the color video image in a modulated third color beam that is linearly polarized in a second plane of polarization;

combining said modulated third color beam with said combined first and second colors image carrying beam in such a manner that they comprise together a composite color video image carrying beam.

21. The method of claim 20, including the steps of creating separate first color, second color, and third color beams, respectively, steps in such a manner that each of said first color, second color, and third color beams are linearly polarized prior to said modulating steps.

22. The method of claim 21, including the steps of:

changing said selected pixel portions of said respective first color, second color, and third color beams by changing the planes of polarization of said selected pixel portions.

23. The method of claim 20, including the steps of simultaneously analyzing said modulated third color beam and combining said modulated third color beam with said combined first and second colors image carrying beam by directing said modulate third color beam and said combined first and second colors image carrying beam onto a polarization-selective surface that either transmits light having linear polarization oriented in said first plane of polarization and reflects light having linear polarization oriented in said second plane of polarization, or, vice versa, reflects light having linear polarization oriented in said firs plane cf polarization and transmits light having linear polarization oriented in said second plane of polarization, with said modulated third color beam, said combined first and second colors image carrying beam, and said polarization-selective surface oriented with respect to each other in such a manner that said modulated third color beam and said combined first and second colors image carrying beam are propagated together from said polarization-selective surface in said composite color video image carrying beam.

24. The method of projecting a color video image, comprising the steps of:

modulating a first color light beam having a first wavelength by changing selected pixel portions of said firs color beam in such a manner that said first color beam carries a first color component of the color video image in a modulated first color beam that is linearly polarized in a first plane of polarization;

modulating a second color light beam having a second wavelength by changing selected pixel portions of said second color beam in such a manner that said second color beam carries a second color component of the color video image in a modulated second color beam that is linearly polarized in a second plane of polarization;

combining said modulated first color beam with said second color beam in such a manner that they comprise a combined first and second colors image carrying beam propagated along a common path with said first color component linearly polarized in said first plane of polarization an said second color component linearly polarized in said second plane of polarization;

modulating a third color light beam by changing selected pixel portions of said third color beam in such a manner that said third color beam carries a third color component of the color video image in a modulated third color beam that is linearly polarized in said first plane of polarization; and

combining said modulated third color beam with said combined first and second colors image carrying beam in such a manner that they comprise together a composite color video image carrying beam.

25. The method of claim 24, including the steps of creating separate first color, second color, and third color beams, respectively, steps in such a manner that each of said first color, second color, and third color beams are linearly polarized prior to said modulating steps

26. The method of claim 25, including the steps of:

changing said selected pixel portions of said respective first color, second color, and third color beams by changing the planes of polarization of said selected pixel portions.

27. The method of claim 24, including the steps of simultaneously analyzing and combining said modulated first color beam and said modulated second color beam by directing said modulated first color beam and said modulated second color beam onto a polarization-selective surface that either transmits light having linear polarization oriented in said first plane of polarization and reflects light having linear polarization oriented in said second plane of polarization, or, vice versa, reflects light having linear polarization oriented in said first plane of polarization and transmits light having linear polarization oriented in said second plane of polarization, modulated first color beam, said modulated second color beam, polarization selective surface oriented with respect to each other in such a manner that said modulated first color beam and said modulated second color beam are propagated together along said common path emanating from said polarization-selective surface.

28. The method of claim 27, including the step of analyzing said modulated third color beam by directing said modulated third color beam onto a polarization-selective surface that either transmits light having linear polarization oriented in said first plane of polarization and reflects light having linear polarization oriented in said second plane of polarization, or, vice versa, reflects light having linear polarization oriented in said first plane of polarization and transmits light having linear polarization oriented in said second plane of polarization.

29. The method of combining a first beam of light with a second beam of linearly polarized light, wherein said first beam of light has a first color component with a first wavelength and a second color component with a second wavelength, and where each of said first and second color components are linearly polarized in a different plane of polarization, comprising the steps of:

positioning a polarization-selective surface that transmits light that is linearly polarized in a first plane and reflects light that is linearly polarized in a second plane in the proximity of both said first and second beams;

reorienting the respective planes of polarization of said first and second color components in said first beam of light to one common plane of polarization and directing it onto said polarization-selective surface for either transmission through the polarization-selective surface or reflection by the polarization-selective surface; and

orienting the plane of polarization of said second beam to whichever of said first or second planes of polarization that is not the same as said common plane of polarization for either reflection through or transmission by said polarization-selective surface for propagation in the same path as said first beam.

30. The method of claim 29, including the steps of having the plane of polarization of said first color component in said first beam oriented orthogonal to the plane of polarization of said second color component in said first beam, and reorienting respective planes of polarization of said first and second color components to a common plane of polarization by directing said first beam through a multiwave retarder that retards the slow axis propagation of both of said first and second color components by an amount that results in retardation of the first color component by an amount of n+1/2 wavelength(s) where n is an integer, such as 1/2, 11/2, 21/2, 31/2, . . . n1/2, and that results in retardation of the second color component by an amount of n wavelength(s), where n is an integer, such as 0, 1, 2, 3, . . ., n.

31. The method of projecting a color video image, comprising the steps of:

modulating a first color light beam having a first wavelength by changing selected pixel portions of said firs color beam in such a manner that said first color beam carries a first color component of the color video image in a modulated first color beam that is linearly polarized in a first plane of polarization;

modulating a second color light beam having a second wavelength by changing selected pixel portions of said second color beam in such a manner that said second color beam carries a second color component of the color video image in a modulated second color beam that is linearly polarized in a second plane of polarization;

combining said modulated first color beam with said second color beam in such a manner that they comprise a combined first and second colors image carrying beam propagated along a common path with said first color component linearly polarized in said first plane of polarization and said second color component linearly polarized in said second plane of polarization;

reorienting said first and second planes of polarization in said first and second colors image carrying beam to a common plane of polarization;

modulating a third color light beam by changing selected pixel portions of said third color beam in such a manner that said third color beam carries a third color component of the color video image in a modulated third color beam that is linearly polarized in a third plane of polarization that is different than said common plane of polarization of said combined first and second colors image carrying beam; and

combining said modulated third color beam with said combined first and second colors image carrying beam in such a manner that they comprise together a composite color video image carrying beam.

32. The method of claim 31, including the steps of creating separate first color, second color, and third color beams, respectively, steps in such a manner that each of said first color, second color, and third color beams are linearly polarized prior to said modulating steps.

33. The method of claim 32, including the steps of:

changing said selected pixel portions of said respective first color, second color, and third color beams by rotating the planes of polarization of said selected pixel portions.

34. The method of claim 31, including the steps of simultaneously analyzing and combining said modulated first color beam and said modulated second color beam by directing said modulated first color beam and said modulated second color beam onto a polarization-selective surface that either transmits light having linear polarization oriented in said first plane of polarization and reflects light having linear polarization oriented in said second plane of polarization, or, vice versa, reflects light having linear polarization oriented in said first plane of polarization and transmits light having linear polarization oriented in said second plane of polarization, modulated first color beam, said modulated second color beam, polarization-selective surface oriented with respect to each other in such a manner that said modulated first color beam and said modulated second color beam are propagated together along said common path emanating from said polarization-selective surface.

35. The method of claim 31, including the steps of:

orienting said first plane of polarization of said modulated first color beam orthogonal to said second plane of polarization of said modulated second color beam; and

reorienting said first and second planes of polarization in said first and second colors image carrying beam to a common plane of polarization by passing said combined first and second colors image carrying beam through a multiwave retarder that retards the first color light by an amount represented by m+1/2 first wavelength(s), where m is an integer such that m+1/2=1/2, 11/2, 21/2, 31/2, . . . , m1/2, and that retards the second color light by an amount represented by n wavelength(s), where n is an integer such that n=0, 1, 2, 3, . . . , n, thereby reorienting the plane of polarization of the first color light to correspond to said second plane of polarization of the second color light.

36. The method of claim 31, including the steps of simultaneously analyzing said modulated third color beam and combining said modulated third color beam with said combined first and second colors image carrying beam by directing said modulated third color beam and said combined first and second colors image carrying beam onto a polarization-selective surface that either transmits light having linear polarization oriented in said common plane or polarization and reflects light having linear polarization oriented in said third plane of polarization, or, vice versa, reflects light having linear polarization oriented in said common plane of polarization and transmits light having linear polarization oriented in said third plane of polarization, with said modulated third color beam, said combined first and second colors image carrying beam, and said polarization-selective surface oriented with respect to each other in such a manner that said modulated third color beam and said combined first and second colors image carrying beam are propagated together from said polarization-selective surface in said composite color video image carrying beam.

37. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a substantially collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state into a converted beam of white polarized light of "S" polarization state, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first, second, and third dichroic mirrors being positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors to said third dichroic mirror, said third dichroic mirror reflecting light of a third of said primary colors;

first, second, and third polarization state modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulation of the state of polarization of the light in each of said modulation means;

first polarizer beam recombiner means positioned to receive the spatially modulated beams from said first and second polarization state modulation means to be polarization analyzed and recombined into a recombined beam having a "P" polarization component from said first polarization stat modulation means and an "S" polarization component from said second polarization state modulation means;

retarder means positioned between said second polarization state modulation means and said first polarizer beam recombine means for converting the modulated beam from said second polarization state modulation means from the "P" polarization state to the "S" polarization state;

second polarizer beam recombine means positioned to receive the recombined modulated beam and the modulated beam from said third polarization state modulation means to be polarization analyzed and recombined into an output beam;

multi-wave retarder means positioned between said first and second polarizer beam recombine means for converting the "P" polarization component of said recombined beam to the "S" polarization state; and

lens means positioned to receive said output beam and project it to said display screen.

38. The system of claim 37, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

39. The system of claim 38, wherein said first, second, and third polarization state modulation means each comprises a transmission type twisted nematic liquid crystal light valve means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

40. The system of claim 39, wherein said light source means comprises a lamp positioned between a collimating lens and a collimating mirror, said collimating mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first side of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

41. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state along said first axis into a converted beam of white polarized light of "S" polarization state along said first axis, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization along said first axis into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first, second, and third dichroic mirrors being positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors to said third dichroic mirror, said third dichroic mirror reflecting light of a third of said primary colors;

first, second, and third light modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulating the intensity of the light in each of said modulation means;

first polarizer beam recombiner means positioned to receive the spatially modulated beams from said first and second light modulation means to be polarization analyzed and recombined into a recombined beam having a "P" polarization component from said first light modulation means and an "S" polarization component from said second light modulation means;

retarder means positioned between said first light modulation means and said first polarizer beam recombine means for converting the modulated beam from said first light modulation means from the "S" polarization state to the "P" polarization state;

second polarizer beam recombine means positioned to receive the recombined modulated beam and the modulated beam from said third light modulation means to be polarization analyzed and recombined into an output beam;

multi-wave retarder means positioned between said first and second polarizer beam recombine means for converting the "P" polarization component of said recombined beam to the "S" polarization state; and

lens means positioned to receive said output beam and project it to said display screen.

42. The system of claim 41, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

43. The system of claim 42, wherein said first, second, and third light modulation means each comprises a transmission type microscopic electrically actuated mechanical shutter means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

44. The system of claim 43, wherein said light source means comprises a lamp positioned between a collimating lens and a collimating mirror, said collimating mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first side of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

45. Color video projector apparatus, comprising:

first color light producing means for producing a substantially linearly polarized first color light beam of a first color in a first color light path;

second color light producing means for producing a substantially linearly polarized second color light beam of a second color in a second color light path;

third color light producing means for producing a substantially linearly polarized third color light beam of a third color in a third color light path;

first color light modulating means positioned in said first color light path for imparting changes in selected portions of said first color light beam in such a manner that said first color light beam carries a first color component of a video image in a first color light path;

second color light modulating means positioned in said second color light path for imparting changes in selected portions of said second color light beam in such a manner that said second color light beam carries a second color component of a video image in a second color modulated light path;

third color light modulating means positioned in said third color light path for imparting changes in selected portions of said third color light beam in such a manner that said third color light beam carries a third color component of a video image in a third color modulated light path;

first polarizing recombining means positioned in said first color modulated light path and in said second color modulated light path for recombining said first color beam after modulation with said second color beam after modulation in such a manner as to produce a recombined first and second color beam propagated in a path that is substantially common for both said first and second color light beams and comprising said first color light linearly polarized substantially in a first plane and said second color light linearly polarized in substantially a second plane, wherein said second plane is different from and not oriented parallel to said first plane;

multiwave retarder means positioned in said path of said recombined first and second color light beam for reorienting the plane of polarization of said first color light in said recombined first and second color beam to be substantially the same as the orientation of said second plane; and

second polarizing recombining means positioned in said third color light path and in said path of said recombined first and second color light beam for recombining said third color beam after modulation with said recombined first and second color beam.

46. The color video projector apparatus of claim 45, wherein said first plane is substantially orthogonal to said second plane.

47. The color video projector apparatus of claim 45, wherein said multiwave retarder retards said first color light in said recombined first and second color light beam by approximately an integer multiple of one wavelength plus one-half wavelength, such as 11/2, 21/2, 31/2, . . . , n1/2, to effectively reorient the plane of polarization of said first color light by about 90-degrees, and wherein said multiwave retarder retards said second color light in said recombined first and second color light beam by approximately an integer multiple of one wavelength, such as 1, 2, 3, . . . , n, to effectively leave the orientation of the plane of polarization of said second color light unchanged.

48. The color video projection system of claim 47, wherein said first color light beam is blue with a wavelength of about 450 nm, said second color light beam is green with a wavelength of about 550 nm, and said multiwave retarder retards said blue and green light beams by about 1130 nm.

49. Beam combining apparatus for combining a first beam of light propagated in a first path with a second linearly polarized beam of light propagated in a second path, wherein said first beam of light has a first color component with a first wavelength and a second color component with a second wavelength, and wherein each of said first and second color components is linearly polarized in a different plane of polarization, comprising:

beamsplitter/combining means positioned in both said first and second beams for combining said first and second beams into a composite beam, wherein said beamsplitter combining means includes a polarization-selective surface that reflects light that is polarized in a first plane and transmits light that is polarized in a second plane, said polarization selective surface being oriented to transmit said second beam and to reflect components of said first beam into the path of the transmitted second beam; and

multiwave retarder means positioned in said first beam of light in said first path for orienting the respective planes of polarization of said first and second color components to both be oriented in the plane of polarization that is reflected by said polarization selective surface.

50. The beam combining apparatus of claim 49, wherein said first path and said second path are orthogonal to each other and said polarization-selective surface is oriented such that both said first beam and said second beam are incident on said surface at about 45-degree angles.

51. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state into a converted beam of white polarized light of "S" polarization state, and for combining the beam o "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first and second dichroic mirrors positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors;

first, second, and third polarization state modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulation of the state of polarization of the light in each of said modulation means;

dichroic beam recombiner means positioned to receive the spatially modulated beams from said first and second polarization state modulation means to be recombined into a recombined beam having a "P" polarization component from said first and second polarization state modulation means;

polarizer beam recombine means positioned to receive the recombined modulated beam and the modulated beam from said third polarization state modulation means to be polarization analyzed and recombined into an output beam;

retarder means positioned between said third polarization state modulation means and said polarizer beam recombine means for converting the modulated beam from said third polarization state modulation means from the "P" polarization state to the "S" polarization state; and

lens means positioned to receive said output beam and project it to said display screen.

52. The system of claim 51, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

53. The system of claim 52, wherein said first, second, and third polarization state modulation means each comprises a transmission type twisted nematic liquid crystal light valve means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

54. The system of claim 53, wherein said light source means comprises a lamp positioned between a collimating lens and a collimating mirror, said collimating mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first site of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

55. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state into a converted beam of white polarized light of "S" polarization state, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first and second dichroic mirrors positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors;

first, second, and third light modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulating the intensity of the light in each of said modulation means;

dichroic beam recombiner means positioned to receive the spatially modulated beams from said first and second light modulation means to be recombined into a recombined beam having a "P" polarization component from said first and second light modulation means;

polarizer beam recombine means positioned to receive the recombined modulated beam and the modulated beam from said third light modulation means to be polarization analyzed and recombined into an output beam;

retarder means positioned between said third light modulation means and said polarizer beam recombine means for converting the modulated beam from said third light modulation means from the "P" polarization state to the "S" polarization state;

lens means positioned to receive said output beam and project it to said display screen.

56. The system of claim 55, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

57. The system of claim 56, wherein said first, second, and third light modulation means each comprises a transmission type microscopic electrically actuated mechanical shutter means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

58. The system of claim 57, wherein said light source means comprises a tungsten filament lamp positioned between a collimating lens and a collimating mirror, said collimating mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first side of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

59. Color video projector apparatus, comprising:

first color light producing means for producing a substantially linearly polarized first color light beam of a first color in a first color light path;

second color light producing means for producing a substantially linearly polarized second color light beam of a second color in a second color light path;

third color light producing means for producing a substantially linearly polarized third color light beam of a third color in a third color light path;

first color light modulating means positioned in said first color light path for imparting changes in selected portions of said first color light beam in such a manner that said first color light beam carries a first color component of a video image in a first color light path;

second color light modulating means positioned in said second color light path for imparting changes in selected portions of said second color light beam in such a manner that said second color light beam carries a second color component of a video image in a second color modulated light path;

third color light modulating means positioned in said third color light path for imparting changes in selected portions of said third color light beam in such a manner that said third color light beam carries a third color component of a video image in a third color modulated light path;

dichroic beam recombining means positioned in said first color modulated light path and in said second color modulated light path for recombining said first color beam after modulation with said second color beam after modulation in such a manner as to produce a recombined first and second color beam propagated in a path that is substantially common for both said first and second color light beams;

polarizing recombining means positioned in said third color light path and in said path of said recombined first and second color light beam for recombining said third color beam after modulation with said recombined first and second color beam; and

retarder means positioned between said third color light modulating means and said polarizing recombining means for converting the modulated beam from said third light modulation means from the "P" polarization state to the "S" polarization state.

60. Beam combining apparatus for combining a first beam of light propagated in a first path with a second linearly polarized beam of light propagated in a second path, wherein said first beam of light has a first color component with a first wavelength and a second color component with a second wavelength, and wherein each of said first and second color components is linearly polarized in the same plane of polarization, comprising beamsplitter/recombining means positioned in both said first and second beams for combining said first and second beams into a composite beam, wherein said beamsplitter recombining means includes a polarization-selective surface that reflects light that is polarized in a first plane and transmits light that is polarized in a second plane, said polarization selective surface being oriented to transmit said second beam and to reflect components of said first beam into the path of the transmitted second beam.

61. The beam combining apparatus of claim 60, wherein said first path and said second path are orthogonal to each other and said polarization-selective surface is oriented such that both said first beam and said second beam are incident on said surface at about 45-degree angles.

62. The method of combining a first beam of light with a second beam of linearly polarized light, wherein said first beam of light has a first color component with a first wavelength and a second color component with a second wavelength, and where each of said first and second color components is linearly polarized in a common plane of polarization, comprising the steps of:

positioning a polarization-selective surface that transmits light that is linearly polarized in a first plane and reflects light that is linearly polarized in a second plane in the proximity of both said first and second beams; and

orienting the plane of polarization of said second beam to whichever of said first or second planes of polarization that is not the same as said common plane of polarization for either reflection through or transmission by said polarization-selective surface for propagation in the same path as said first beam.

63. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam cf white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state into a converted beam of white polarized light of "S" polarization state, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first and second dichroic mirrors positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors;

first, second, and third polarization state modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulation of the state of polarization of the light in each of said modulation means;

first polarizer beam recombiner means positioned to receive the spatially modulated beams from said first and second polarization state modulation means to be recombined into a recombined beam having an "S" polarization component from said first polarization state modulation means and a "P" polarization component from said second polarization state modulation means;

retarder means positioned between said first polarization state modulation means and said first polarizer beam recombiner means for converting the modulated beam from said first polarization state modulation means from the "P" polarization state to the "S" polarization state;

beam analyzer means positioned to receive the modulated beam from said third polarization state modulation means for analyzing said third modulated beam;

dichroic beam recombiner means positioned to receive the recombined modulated beam and the modulated beam from said beam analyzer means to be recombined into an output beam; and

lens means positioned to receive said output beam and project it to said display screen.

64. The system of claim 63, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

65. The system of claim 64, wherein said first, second, and third polarization state modulation means each comprises a transmission type twisted nematic liquid crystal light valve means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

66. The system of claim 65, wherein said light source means comprises a lamp positioned between a collimating lens and a collimating mirror, said mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first side of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

67. A system for projecting full color images from television or other video sources onto a display screen, comprising:

light source means for providing a collimated beam of white projection light;

polarizer beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state into a converted beam of white polarized light of "S" polarization state, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization into a combined beam of "S" polarization along said first axis;

dichroic mirror means for first separating said combined beam of white polarized light of "S" polarization into three beams of polarized light of different primary colors to be polarization state modulated, said dichroic mirror means comprising first and second dichroic mirrors positioned to receive said combined beam of white polarized light of "S" polarization, said first dichroic mirror reflecting light of a first of said primary colors and transmitting light of a second and third of said primary colors to said second dichroic mirror, said second dichroic mirror reflecting light of a second of said primary colors and transmitting light of a third of said primary colors;

first, second, and third light modulation means for selectively spatially modulating a primary color component video image onto each of said first, second, and third primary colors respectively received from said dichroic mirror means by modulating the intensity of the light in each of said modulation means;

first polarizer beam recombiner means positioned to receive the spatially modulated beams from said first and second light modulation means to be recombined into a recombined beam having an "S" polarization component from said first light modulation means and a "P" polarization component from said second light modulation means;

retarder means positioned between said first light modulation means and said first polarizer beam recombine means for converting the modulated beam from said first light modulation means from the "P" polarization state to the "S" polarization state;

beam analyzer means positioned to receive the modulated beam from said third light modulation means for analyzing said third modulated beam;

dichroic beam recombiner means positioned to receive the recombined modulated beam and the modulated beam from said beam analyzer means to be recombined into an output beam; and

lens means positioned to receive said output beam and project it to said display screen.

68. The system of claim 67, wherein said polarizer beamsplitter combiner means further comprises:

multirefractive layer means making an angle of substantially 45 degrees with said collimated white projection light for splitting said collimated white projection light into its "P" and "S" polarization components; and

specular mirror means making an angle of substantially 45 degrees with said second optic axis for redirecting said "S" polarization component along said first optic axis.

69. The system of claim 68, wherein said first, second, and third light modulation means each comprises a transmission type microscopic electrically actuated mechanical shutter means having a plurality of pixels, said system further including means for selectively scanning said pixels for deriving therefrom said video image.

70. The system of claim 69, wherein said light source means comprises a tungsten filament lamp positioned between a collimating lens and a collimating mirror, said mirror, said lamp, and said collimating lens being positioned in sequence on said first optic axis on a first side of said polarizer beamsplitter combiner means to direct said collimated white projection light onto said multirefractive layer means.

71. Color video projector apparatus, comprising:

first color light producing means for producing a substantially linearly polarized first color light beam of a first color in a first color light path;

second color light producing means for producing a substantially linearly polarized second color light beam of a second color in a second color light path;

third color light producing means for producing a substantially linearly polarized third color light beam of a third color in a third color light path;

first color light modulating means positioned in said first color light path for imparting changes in selected portions of said first color light beam in such a manner that said first color light beam carries a first color component of a video image in a first color light path;

second color light modulating means positioned in said second color light path for imparting changes in selected portions of said second color light beam in such a manner that said second color light beam carries a second color component of a video image in a second color modulated light path;

third color light modulating means positioned in said third color light path for imparting changes in selected portions of said third color light beam in such a manner that said third color light beam carries a third color component of a video image in a third color modulated light path;

polarizing recombining means positioned in said first color modulated light path and in said second color modulated light path for recombining said first color beam after modulation with said second color beam after modulation in such a manner as to produce a recombined first and second color beam propagated in a path that is substantially common for both said first and second color light beams and comprising said first color light linearly polarized substantially in a first plane and said second color light linearly polarized in substantially a second plane, wherein said second plane is different from and not oriented parallel to said first plane;

beam analyzing means positioned in said third color light path for analyzing said modulated third color light beam; and

dichroic beam recombiner means positioned to receive the recombined modulated beam and the modulated beam from said beam analyzing means to be recombined into an output beam.

72. Color video projector apparatus, comprising:

first color light producing means for producing a substantially linearly polarized first color light beam of a first color in a first color light path;

second color light producing means for producing a substantially linearly polarized second color light beam of a second color in a second color light path, wherein said second color light path is orthogonal to said first color light path;

third color light producing means for producing a substantially linearly polarized third color light beam of a third color in a third color light path, wherein said third color light path is in parallel, spaced apart relation to said first color light path;

first color light modulating means positioned in said first color light path for imparting changes in selected portions of said first color light beam in such a manner that said first color light beam carries a first color component of a video image in said first color light path;

second color light modulating means positioned in said second color light path and orthogonal to said first color light producing means such that said first and second color light modulating means define two adjacent sides of a first cube, having a first included angle of substantially ninety (90) degrees, for imparting changes in selected portions of said second color light beam in such a manner that said second color light beam carries a second color component of a video image in said second color light path;

third color light modulating means positioned in said third color light path and orthogonal to said second color light modulating means such that said second and third color light modulating means define two adjacent sides of a second cube, having a second included angle of substantially ninety (90) degrees, and further wherein said second color light modulating means is common to said first defined cube and said second defined cube, for imparting changes in selected portions of said third color light beam in such a manner that said third color light beam carries a third color component of a video image in said third color light path;

dichroic color recombining means positioned in said first color modulated light path and in said second color modulated light path, such that said dichroic color recombining means substantially bisects said first included angle of said first cube defined by said first color light modulating means and said second color light modulating means forming a diagonal within said first defined cube, for recombining said first color beam after modulation with said second color beam after modulation in such a manner as to produce a recombined first and second color beam propagated in a path that is substantially parallel to said first color light path and wherein said recombined beam comprises said first color light and said second color light linearly polarized substantially in a first plane;

beam redirecting means positioned in said third color modulated light path in parallel spaced-apart relation to said dichroic color recombining means for redirecting said third color light beam after modulation in a redirected path that is substantially parallel to said second color light path;

retarder means positioned in said redirected third color light beam path after modulation and being substantially linearly aligned with said second color light modulating means, such that said retarder means, said third color light modulating means, and said beam redirecting means define a polyhedron whose two parallel congruent faces are triangular, for reorienting the plane of polarization of said third color light to a second plane; and

polarizing recombining means positioned in said third color light path and in said path of said recombined first and second color light beam for recombining said third color beam after modulation with said recombined first and second color beam to form an output beam.

73. The color video projector apparatus of claim 72, wherein said first plane of polarization is substantially orthogonal to said second plane of polarization.

74. The color video projector apparatus of claim 73, wherein said first, second, and third color light producing means comprise:

white light source means for providing a substantially linearly polarized collimated beam of white projection light in a white projection light path;

blue light dichroic mirror means positioned in said white projection light path and substantially linearly aligned with said dichroic color recombining means for producing a blue color light beam in a blue color light path that is substantially parallel to said first color light modulating means;

blue color light beam redirecting means positioned in said blue color light path and oriented at substantially forty five (45) degrees from said first color light modulating means for redirecting said first color light path ninety (90) degrees to be incident on said first color light modulating means; and

green dichroic mirror means substantially linearly aligned with said dichroic color recombining means in parallel, spaced apart relation to said blue dichroic mirror means and substantially bisecting said second included angle between said second color light modulating means and said third color light modulating means for producing a green color light beam in a green color light path that is incident on said second color light modulating means, and for producing a rad color light beam in a red color light path that is incident on said third color light modulating means.

75. The color video projector apparatus of claim 74, wherein said white light source means includes polarizing beamsplitter combiner means positioned to receive said collimated white projection light for splitting said collimated white projection light into a beam of white polarized light of "P" polarization state along a first axis, and into a beam of white polarized light of "S" polarization state along a second axis, said first and second axes being mutually orthogonal, for converting the light of "P" polarization state along said first axis into a converted beam of white polarized light of "S" polarization state along said first axis, and for combining the beam of "S" polarization state along said second axis with the converted beam of white polarized light of "S" polarization along said first axis into a combined beam of "S" polarization along said first axis.

76. The color video projector apparatus of claim 72 including lens means to receive said output beam and project it to a display screen.