Display system with equal path lengths

• US 4,864,390 A
• Filed: 12/29/1988
• Issued: 09/05/1989
• Est. Priority Date: 08/22/1986
• Status: Expired due to Term

• Current Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Original Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Inventors: Shimizu, Jeffrey A., Bradley, Ralph H. Jr., Goldenberg, Jill F., Eskin, Joshua D., Guerinot, William F., McKechnie, Thomas S.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Bauer, Robert M.
• Application Number:
  US07/292,618
• Time in Patent Office: 250 Days
• Field of Search: 358/61, 358/62, 358/232, 358/233, 358/236, 340/784, 340/330, 350/337, 350/338, 350/345, 350/347 E, 350/400, 350/401, 350/403, 350/408, 353/31, 353/34
• US Class Current: 348/751
• CPC Class Codes: G02F 1/1313 specially adapted for a particular application
• 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

Display systems useful for projection video and television systems are provided to perform with high efficiency and good color rendition. In these systems, color may be provided, as one example, by various light valves, such as liquid crystal displays. Each of the liquid crystal displays are positioned at equal path distances from an illuminating subsystem, and have equal path distances from the light valves to a projection subsystem. This enables optimum illumination of each of the light valves. Various embodiments of arranging the light valves, as well as providing illumination are described.

Claims

1. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem said second path length being equal for all transmission light valves.

2. A display system according to claim 1, wherein at least three light valves are included in said modulation subsystem.

3. A display system according to claim 1, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

4. A display system according to claim 3, wherein said elongated light source has a length of at most about 1.06 inches.

5. A display system according to claim 3 or claim 4, wherein said light source is an elongated arc.

6. A display system according to claim 1 or claim 3, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystals displays modulating green light, and a third of said liquid crystal displays modulating blue light.

7. A display system according to claim 6, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem.

8. A display system according to claim 6, wherein said illumination subsystem provides one of critical illumination, Kohler illumination, or a combination of critical illumination and Kohler illumination.

9. A display system according to claim 6, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system.

10. A display system according to claim 1 or 2, wherein said illumination subsystem provides one of critical illumination, Kohler illumination, or a combination of critical illumination and Kohler illumination.

11. A display system according to claim 1, wherein said illumination subsystem, said modulation subsystem, and said projection subsystem provide a projection TV system.

12. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illuminating substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves.

13. A projection TV system according to claim 12, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light.

14. A projection TV system according to claim 13, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of each of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem.

15. A projection TV system according to claim 13, wherein said illumination subsystem provides one of critical illumination, Kohler illumination, or a combination of critical illumination and Kohler illumination.

16. A projection TV system according to claim 13, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not originally passing to said modulation subsystem to said condenser lens system.

17. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not originally passing to said modulation subsystem to said condenser lens system, wherein said light source includes an inner and an outer envelope with plane mirrors within said outer envelope to direct reflected light to at least one image position adjacent said light source, and wherein said reflector means includes reflectors to collect and redirect light to at least one of said light source or said image position for passage through said condenser lens system.

18. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not originally passing to said modulation subsystem to said condenser lens system, wherein said light source directs light radially in all directions including through said condenser lens system, and wherein said reflector means are provided to redirect light not previously passing through said condenser lens system in a direction for passing through said condenser lens system.

19. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not originally passing to said modulation subsystem to said condenser lens system, wherein said light source provides randomly polarized light, and wherein a polarizing beamsplitter and at least one quarterwave plate are provided for directing a desired polarization of said polarized light to said modulation subsystem.

20. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length path from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsytem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not originally passing to said modulation subsystem to said condenser lens system, wherein said light source has only one envelope with plane mirrors being inside or outside said envelope to direct reflected light to at least one image position adjacent said light source, and wherein said reflector means includes reflectors to collect and redirect light to at least one of said light source or said image position for passage through said condenser lens system.

21. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes at least one metal halide lamp or at least one xenon arc lamp.

22. A projection TV system according to claim 21, wherein said illumination subsystem has at least two elongated lamps provided side by side.

23. A projection TV system according to claim 21, wherein said illumination subsystem has a single lamp with at least two elongated arcs provided side by side.

24. A display device comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, said modulation subsystem including at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein an incandescent light source is provided in said illumination subsystem to supply initial illumination until an arc lamp light source can supply sufficient illumination.

25. A projection video system according to claim 24.

26. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem, and wherein entrance and exit locations of said illumination subsystem and said projection subsystem are changed relative to said modulation subsystem.

27. A display system according to claim 26, wherein said dichroic filters and mirrors at one side of said modulation subsystem are arranged in parallel rows to said dichroic filters and mirrors at another side of said modulation subsystem, said first, second and third liquid crystal displays being individually arranged between said parallel rows of dichroic filters and mirrors.

28. A display system according to claim 26, wherein said dichroic filters and mirrors are arranged at Brewster'"'"'s angle to the path of light in said modulation subsystem, and wherein said first, second and third liquid crystal displays are perpendicular to the path of said light.

29. A display system according to claim 26, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

30. A display system according to claim 29, wherein said elongated light source has a length of at most about 1.06 inches.

31. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystals displays modulating blue light, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem, and wherein lens portions of said projection subsystem are disposed in said modulation subsystem, said lens portions being color corrected for said liquid crystal displays.

32. A display system according to claim 31, wherein two separate lens portions are provided relative to a respective liquid crystal display.

33. A display system according to claim 31, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

34. A display system according to claim 33, wherein said elongated light source has a length of at most about 1.06 inches.

35. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem, and wherein at least one further dichroic filter is disposed in said modulation subsystem, said further filter being rotatable to vary wavelengths of said light passed by said liquid crystal displays.

36. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illumination beam to said projection subsystem, each of said transmission light valves being disposed at first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, and wherein each of said liquid crystal displays is disposed at a tilt from a direction of light travel.

37. A display system according to claim 36, wherein said elongated light source has a length of at most about 1.06 inches.

38. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illumination beam to said projection subsystem, each of said transmission light valves being disposed at first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, and wherein each of said liquid crystal displays is disposed at a tilt from a direction of light travel.

39. A display system according to claim 38, wherein a prism is provided to eliminate trapezoidal distortion of an image of said liquid crystal display.

40. A display system according to claim 39, wherein said prism is located adjacent said liquid crystal display, said prism having an angle B given by ##EQU3## where A is the angle of tilt of said liquid crystal display and N is the refractive index of said prism.

41. A display system according to claim 39, wherein said prism is located adjacent an image of said liquid crystal display, said prism having an angle B given by ##EQU4## where A is the angle of tilt of said liquid crystal display, N is the refractive index of said prism, and M is the magnification of said image.

42. A display system according to claim 38, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

43. A display system according to claim 42, wherein said elongated light source has a length of at most about 1.06 inches.

44. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system, wherein said light source includes an inner and an outer envelope with plane mirrors within said outer envelope to direct reflected light to at least one image position adjacent said light source, and wherein said reflector means includes reflectors to collect and redirect light to at least one of said light source or said image position for passage through said condenser lens system.

45. A display system according to claim 44, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

46. A display system according to claim 45, wherein said elongated light source has a length of at most about 1.06 inches.

47. A display system comprising an illumination subsystem providing a single illumination beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system, wherein said light source directs light radially in all directions including through said condenser lens system, and wherein said reflector means are provided to redirect light not originally passing through said condenser lens system in a direction for passing through said condenser lens system.

48. A display system according to claim 47, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

49. A display system according to claim 48, wherein said elongated light source has a length of at most about 1.06 inches.

50. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system, wherein said light source provides randomly polarized light, and wherein a polarizing beamsplitter and at least one quarterwave plate are provided for directing a desired polarization of said polarized light to said modulation subsystem.

51. A display system according to claim 50, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

52. A display system according to claim 51, wherein said elongated light source has a length of at most about 1.06 inches.

53. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, and wherein said illumination subsystem includes at least one metal halide lamp or at least one xenon arc lamp.

54. A display system according to claim 53, wherein said illumination subsystem has at least two elongated lamps provided side by side.

55. A display system according to claim 53, wherein said illumination subsystem has a single lamp with at least two elongated arcs provided side by side.

56. A display system according to claim 53, wherein said illumination subsystem includes an elongated light source having a length in the range of 0.3 to 1.5 inches.

57. A display system according to claim 56, wherein said elongated light source has a length of at most about 1.06 inches.

58. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, and wherein each of said light valves is disposed at a tilt from a direction of light travel.

59. A display system according to claim 58, wherein a prism is provided to eliminate trapezoidal distortion of an image of said light valves.

60. A display system according to claim 59, wherein said prism is located adjacent said light valves, said prism having an angle B given by ##EQU5## where A is the angle of tilt of said light valves and N is the refractive index of said prism.

61. A display system according to claim 59, wherein said prism is located adjacent an image of said light valves, said prism having an angle B given by ##EQU6## where A is the angle of tilt of said light valves, N is the refractive index of said prism, and M is the magnification of said image.

62. A display system according to claim 58, wherein at least three light valves are included in said modulation subsystem.

63. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, and wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system.

64. A display system according to claim 63, wherein said light source includes an inner and an outer envelope with plane mirrors within said outer envelope to direct reflected light to at least one image position adjacent said light source, and wherein said reflector means includes reflectors to collect and redirect light to at least one of said light source or said image position for passage through said condenser lens system.

65. A display system according to claim 63, wherein said light source directs light radially in substantially all directions including through said condenser lens system, and wherein said reflector means are provided to redirect light not previously passing through said condenser lens system in a direction for passing through said condenser lens system.

66. A display system according to claim 63, wherein said light source has only one envelope with plane mirrors being inside or outside said envelope to direct reflected light to at least one image position adjacent said light source, and wherein said reflector means includes reflectors to collect and redirect light to at least one of said light source or said image position for passage through said condenser lens system.

67. A display system according to claim 63, wherein at least three light valves are included in said modulation subsystem.

68. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsytem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, wherein said illumination subsystem includes a light source, at least one reflector means for collecting light not passing to said modulation subsystem, and a condenser lens system for passing light to said modulation subsystem, said at least one reflector means redirecting said light not previously passing to said modulation subsystem to said condenser lens system, wherein said light source provides randomly polarized light, and wherein a polarizing beamsplitter and at least one quarterwave plate are provided for directing a desired polarization of said polarized light to said modulation subsystem.

69. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, and wherein said illumination subsystem includes at least one metal halide lamp or at least one xenon arc lamp.

70. A display system according to claim 69, wherein at least three light valves are included in said modulation subsystem.

71. A display system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light values directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from said illumination subsystem, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from said projection subsystem, said second path length being equal for all transmission light valves, and wherein said illumination subsystem has at least two elongated lamps provided side by side.

72. A display system according to claim 71, wherein at least three light valves are included in said modulation subsystem.

73. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing a least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, and wherein entrance and exit locations of said illumination subsystem and said projection subsystem are changed relative to said modulation subsystem.

74. A projection TV system according to claim 73, wherein said dichroic filters and mirrors at one side of said modulation subsystem are arranged in parallel rows to said dichroic filters and mirrors at another side of said modulation subsystem, said first, second and third liquid crystal displays being individually arranged between said parallel rows of dichroic filters and mirrors.

75. A projection TV system according to claim 73, wherein said dichroic filters and mirrors are arranged at Brewster'"'"'s angle to the path of light in said modulation subsystem, and wherein said first, second and third liquid crystal displays are perpendicular to the path of said light.

76. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of each of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem, and wherein lens portions of said projection subsystem are disposed in said modulation subsystem, said lens portions being color corrected for said liquid crystal displays.

77. A projection TV system according to claim 76, wherein a separate lens portion is provided relative to two different liquid crystal displays.

78. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, wherein said modulation subsystem further includes a series of dichroic filters and mirrors for passing light through a respective one of each of said three liquid crystal displays and for recombining each of said red light, said green light, and said blue light before said projection subsystem, and wherein at least one further dichroic filter is disposed in said modulation subsystem, said further filter being rotatable to vary wavelengths of said light passed by said liquid crystal displays.

79. A projection TV system comprising an illumination subsystem providing a single illuminating beam, a modulation subsystem, and a projection subsystem, wherein said modulation subsystem includes at least two transmission light valves, each of said transmission light valves directly passing at least a portion of said single illuminating beam to said projection subsystem, each of said transmission light valves being disposed at a first path length from the illumination substage, said first path length being equal for all transmission light valves, and each of said transmission light valves being disposed at a second path length from the projection subsystem, said second path length being equal for all transmission light valves, wherein said light valves in said modulation subsystem include three transmission liquid crystal displays, a first of said liquid crystal displays modulating red light, a second of said liquid crystal displays modulating green light, and a third of said liquid crystal displays modulating blue light, and wherein each of said liquid crystal displays is disposed at a tilt from a direction of light travel.

80. A projection TV system according to claim 79, wherein a prism is provided to eliminate trapezoidal distortion of an image of said liquid crystal display.

81. A projection TV system according to claim 80, wherein said prism is located adjacent said liquid crystal display, said prism having an angle B given by ##EQU7## where A is the angle of tilt of said liquid crystal display and N is the refractive index of said prism.

82. A projection TV system according to claim 80, wherein said prism is located adjacent an image of said liquid crystal display, said prism having an angle B given by ##EQU8## were A is the angle of tilt of said liquid crystal display, N is the refractive index of said prism, and M is the magnification of said image.