Projection color display apparatus

• US 5,135,300 A
• Filed: 01/25/1991
• Issued: 08/04/1992
• Est. Priority Date: 02/01/1990
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kida, Hiroshi, Shikama, Shinsuke, Usui, Masahiro, Toide, Eiichi, Kondo, Mitsushige
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Dowling, William C.
• Application Number:
  US07/645,631
• Time in Patent Office: 557 Days
• Field of Search: 353/31, 353/30, 353/33, 353/34, 353/37, 353/81, 353/94, 353/20, 353/122, 353/84, 358/253, 358/250, 358/242, 359/48, 359/66, 359/580, 359/581, 359/589
• US Class Current: 353/31
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

Three light fluxes are modulated by corresponding light valves so as to project a color image on a screen. An interference filter for selectively transmitting a light flux which is emitted in a direction perpendicular to a light emitting surface of the interference filter is disposed on the light-emitting portion so as to increase the intensity of light fluxes which are emitted in the forward direction. A light-flux-emitting portion of a light source and the light valve have approximately the same configuration so that the intensity of the light fluxes to be projected on the light valves is increased.

Claims

1. A projection color display apparatus for projecting a color image on a screen comprising:

a plurality of light sources having planar light-flux-emitting portions for emitting a plurality of light source fluxes;

a plurality of optical interference filters provided on the light-flux-emitting portion of each of said plurality of light sources for emitting a plurality of light fluxes perpendicular to a surface of said planar light-flux-emitting portions;

a plurality of light valves disposed in a path of each of the plurality of light fluxes emitted by said plurality of light sources so as to modulate the plurality of light fluxes in two dimensions; and

an optical synthetic system for synthesizing the modulated plurality of light fluxes into one combined light flux.

2. The projection color display apparatus of claim 1, wherein said plurality of light sources are red, blue and green light sources.

3. The projection color display apparatus of claim 2, wherein said plurality of optical interference filters are short wavelength pass filters, which only transmit a main peak wavelength light flux of each of said plurality of light sources, such as, red light, blue light, and green light.

4. The projection color display apparatus of claim 1, wherein each of said plurality of light sources includes a plurality of linear light-emitting tubes, a reflecting mirror disposed behind said plurality of light-emitting tubes and a diffusion plate disposed in front of said plurality of light-emitting tubes.

5. The projection color display apparatus of claim 1, wherein each of said plurality of light sources includes a curved light-emitting tube, a reflecting mirror disposed behind said curved light-emitting tube, and a diffusion plate disposed in front of said curved light-emitting tube.

6. The projection color display apparatus of claim 1, wherein said optical synthetic system includes a plurality of dichroic mirrors.

7. The projection color display apparatus of claim 1, wherein said optical synthetic system includes a dichroic prism.

8. The projection color display apparatus of claim 1, wherein the light-flux-emitting portions of said plurality of light sources are quadrangular in shape.

24. The projection color display apparatus of claim 1, wherein said plurality of light sources are monochrome CRTs.

9. A projection color display apparatus for projecting a color image on a screen comprising:

a white light source for emitting a white light flux;

an optical separation system for separating the white light flux emitted from said white light source into three light fluxes of different colors;

a plurality of light valves disposed in a path of the three light fluxes for modulating the three light fluxes in two dimensions; and

an optical synthetic system for synthesizing the modulated three light fluxes into one combined light flux;

said white light source including a light-flux-emitting portion which has approximately the same shape as each of said plurality of light valves and which is provided with an optical interference filter for emitting the white light flux in a direction perpendicular to a light-emitting surface provided with the optical interference filter.

10. The projection color display apparatus of claim 9, wherein said white light source is a cathode ray tube (CRT).

11. The projection color display apparatus of claim 9, wherein said optical separation system and said optical synthetic system include a plurality of dichroic mirrors.

12. The projection color display apparatus of claim 9, wherein said optical interference filter is a three part band pass filter which transmits red light, blue light and green light.

13. The projection color display apparatus of claim 9, wherein the light-flux-emitting portion of said white light source is quadrangular in shape.

14. The projection color display apparatus of claim 9, wherein said white light source further includes a light-flux-emitting portion,

a parabolic reflecting mirror disposed behind said light-flux-emitting portion, and

a light emission regulator provided between said light-flux-emitting portion and said parabolic reflecting mirror, said light emission regulator including reflecting means provided on an inner surface of said light emission regulator, adjacent to said light-flux-emitting portion.

15. The projection color display apparatus of according claim 14, wherein said optical separation system and said optical synthetic system include a plurality of dichroic mirrors.

16. The projection color display apparatus of claim 14, wherein said optical interference filter is a three part band pass filter which transmits red light, blue light and green light.

17. The projection color display apparatus of claim 14, wherein the light-flux-emitting portion of said white light source is quadrangular in shape.

18. The projection color display apparatus of claim 9, wherein the white light source is a halogen lamp.

19. The projection color display apparatus of claim 9, wherein the white light source is a metal-halide lamp.

20. The projection color display apparatus of claim 9 wherein the white light source is a monochrome CRT.

21. The projection color display apparatus of claim 14, wherein the white light source is a halogen lamp.

22. The projection color display apparatus of claim 14, wherein the white light source is a metal-halide lamp.

23. The projection color display apparatus of claim 14, wherein the white light source is a monochrome CRT.

25. A projection color display apparatus comprising:

a plurality of light source means for emitting a plurality of parallel luminous fluxes;

a plurality of light valves, each receiving one of said plurality of parallel luminous fluxes, for modulating an intensity of the received one of the plurality of parallel luminous fluxes in two dimensions;

a optical synthetic system for synthesizing the modulated plurality of parallel luminous fluxes into a two-dimensional color image; and

a projection lens for magnifying the two-dimensional color images and projecting the magnified two-dimensional color image on a screen;

each of said plurality of light source means including,

a planar light source for emitting a planar light flux in a direction of one of said plurality of light valves,

planar reflecting means for reflecting an additional light flux in the direct of one of said plurality of light valves, and

an optical interference filter including a light emitting surface for receiving and filtering the planar light flux and the additional light flux to form said parallel luminous flux perpendicular to the light emitting surface of said optical interference filter.

26. The projection color display apparatus of claim 25, wherein said plurality of light source means are red, blue, and green light source means.

27. The projection color display apparatus of claim 26, wherein said optical interference filter is a short wavelength pass filter, which only transmits a main peak wavelength light flux of each of said plurality of light source means, such as, red light, green light, or blue light.

28. The projection color display apparatus of claim 25, wherein each of said plurality of light source means and a corresponding one of said plurality of light valves are positioned as close as possible, thereby minimizing the dimensions of said projection color display apparatus.

29. The projection color display apparatus of claim 25, wherein a condenser lens is positioned between each of said plurality of light source means and a corresponding one of said plurality of light valves.

30. The projection color display apparatus of claim 25, wherein said planar light source includes a planar light source aperture through which the planar light flux is emitted and each of said plurality of light valves includes a light receiving surface for receiving one of said plurality of parallel luminous fluxes, wherein the planar light source aperture, the light receiving surface, and the light emitting surface of said optical interference filter are all of a similar quadrangular shape.

31. The projection color display apparatus of claim 30, wherein said planar light source further includes at least one fluorescent discharge tube and a diffusion plate for producing a monochromatic light spectrum.

32. The projection color display apparatus of claim 31, where said at least one fluorescent discharge tube is a linear fluorescent discharge tube.

33. The projection color display apparatus of claim 31, wherein said at least one fluorescent discharge tube is a curved fluorescent discharge tube.

34. The projection color display apparatus of claim 31, wherein said diffusion plate is composed of ground glass.

35. The projection color display apparatus of claim 25, said planar reflecting means including a planar reflecting mirror positioned such that said planar light source is between the planar reflecting mirror and said optical interference filter.

36. The projection color display apparatus of claim 25, wherein said planar reflecting means includes a metal coating on said planar light source.

37. The projection color display apparatus of claim 25, wherein said optical synthetic system includes a plurality of dichroic mirrors.

38. The projection color display apparatus of claim 25, wherein said optical synthetic system includes a dichroic prism.

39. The projection color display apparatus of claim 25, wherein said optical interference filter is a multilayered film including a high refractive-index material layer and a low refractive-index material layer.

40. A projection color display apparatus comprising:

white light source means for emitting a white parallel luminous flux;

an optical separation system for separating the white parallel luminous flux into a plurality of colored parallel luminous fluxes;

a plurality of light valves, each receiving one of said plurality of colored parallel luminous fluxes, for modulating an intensity of the received on of the plurality of colored parallel luminous fluxes in two dimensions;

an optical synthetic system for synthesizing the modulated plurality of colored parallel luminous fluxes into a two-dimensional color image; and

a projection lens for magnifying the two-dimensional color image and projecting the magnified two-dimensional color image on a screen;

said white light source means including,

a cathode ray tube light source means for emitting a white light flux in a direction of one of said plurality of light valves, and

an optical interference filter including a light emitting surface for receiving and filtering the white light flux to form said white parallel luminous flux and emitting the white parallel luminous flux perpendicular to the light emitting surface of said optical interference filter.

41. The projection color display apparatus of claim 40, where the plurality of colored parallel luminous fluxes are red, blue, and green parallel luminous fluxes.

42. The projection color display apparatus of claim 41, wherein said optical interference filter is a three part band pass filter which transmits red light, green light, and blue light.

43. The projection color display apparatus of claim 40, wherein said white light source means is a halogen lamp.

44. The projection color display apparatus of claim 40, wherein said white light source means is a metal-halide lamp.

45. The projection color display apparatus of claim 40, wherein said white light source means is a monochrome CRT.

46. The projection color display apparatus of claim 40, wherein said cathode ray tube light source means includes a light source aperture through which the white light flux is emitted and each of said plurality of light valves includes a light receiving surface for receiving one of said plurality of colored parallel luminous fluxes, wherein the light source aperture, the light receiving surface, and the light emitting surface of said optical interference filter are all of a similar quadrangular shape.

47. The projection color display apparatus of claim 46, wherein said cathode ray tube light source means further includes a face plate and grass plate with a coolant sealed therebetween.

48. The projection color display apparatus of claim 46, wherein said cathode ray tube light source means further includes,

a parabolic reflecting mirror positioned behind the light source aperture, and

a light source emission regulator, positioned in front of the light source aperture, including reflecting means provided on an inner surface of said light source emission regulator, adjacent to the light source aperture.

49. The projection color display apparatus of claim 46, wherein said white light source means is a halogen lamp.

50. The projection color display apparatus of claim 46, wherein the white light source means is a metal-halide lamp.

51. The projection color display apparatus of claim 46, wherein said white light source means is a monochrome CRT.

52. The projection color display apparatus of claim 40, wherein said optical synthetic system includes a plurality of dichroic mirrors.

53. The projection color display apparatus of claim 40, wherein said optical synthetic system includes a dichroic prism.

54. The projection color display apparatus of claim 40, wherein said optical interference filter is a multilayered film including a high refractive-index material layer and a lower refractive-index material layer.