Projector

• US 6,722,768 B1
• Filed: 10/06/2000
• Issued: 04/20/2004
• Est. Priority Date: 10/06/1999
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Takezawa, Takeshi
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US09/679,296
• Time in Patent Office: 1,292 Days
• Field of Search: 353/20, 353/31, 353/34, 353/33, 353/37, 353/38, 349/5, 349/8, 349/9, 349/18, 349/193
• US Class Current: 353/20
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• 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

A technique capable of increasing contrast of a projected and displayed image of a projector. A projector includes an illuminating system that emits illumination light, a liquid crystal light valve for modulating light from the illuminating system according to image information, and a projection system for projecting image light formed on a light emission surface of the liquid crystal light valve. A liquid crystal light valve includes a liquid crystal panel, first and second polarizers disposed on the side of the light incidence surface and on the side of the light emission surface of the liquid crystal panel, and first and second compensating plates disposed between the liquid crystal panel and the first and second polarizers, respectively. By using such a liquid crystal light valve, incidence angle dependency of contrast of image light formed on the light emission surface of the liquid crystal light valve is reduced, whereby it is possible to increase contrast of an image projected and displayed by the projection system.

Claims

1. A projector, comprising:

an illuminating system that emits illumination light;

a liquid crystal light valve that modulates light from the illuminating system according to image information; and

a projection system that projects image light formed on a light emission surface of the liquid crystal light valve;

wherein the illumination system includes;

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes and illuminates the plurality of partial light emitted from the light dividing element on a light incidence surface of the liquid crystal light valve;

wherein the liquid crystal light valve includes;

a liquid crystal panel;

a first polarizer located on a side of the light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first optical compensating plate that reduces a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the first optical compensating plate being located between the liquid crystal panel and the first polarizer; and

a second optical compensating plate that reduces a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the second optical compensating plate being located between the liquid crystal panel and the second polarizer.

2. A projector as claimed in claim 1, wherein the liquid crystal panel is in a TN mode.

3. A projector as claimed in claim 1 further comprising a circuit board that supplies signal to the liquid crystal panel.

4. A projector as claimed in claim 1 further comprising a power source that supplies electric power to the liquid crystal panel.

5. A projector as claimed in claim 1, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

6. A projector, comprising:

an illuminating system that emits illumination light;

a color separation system that separates the illumination light emitted from the illumination system into first to third color lights having three color components;

first to third liquid crystal light valves that respectively modulate the first to third color lights separated by the color separation system according to image information;

a color synthesizing section that synthesizes image lights formed on light emission surfaces of the first to third liquid crystal valves; and

a projection system that projects synthesized light emitted from the color synthesizing section;

wherein the illumination system includes;

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes and illuminates the plurality of partial light emitted from the light dividing element on a light incidence surface of the liquid crystal light valve;

and wherein each of the first to third liquid crystal light valves includes;

a liquid crystal panel;

a first polarizer located on a side of the light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first optical compensating plate that reduces a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the first optical compensating plate being located between the liquid crystal panel and the first polarizer; and

a second optical compensating plate that reduces a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the second optical compensating plate being located between the liquid crystal panel and the second polarizer.

7. A projector as claimed in claim 6, wherein the liquid crystal panel is in a TN mode.

8. A projector as claimed in claim 6 further comprising a circuit board that supplies signals to the liquid crystal panel.

9. A projector as claimed in claim 6 further comprising a power source that supplies electric power to the liquid crystal panel.

10. A projector as claimed in claim 6, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

11. A projector, comprising:

an illuminating system that emits illumination light;

a liquid crystal light valve that modulates light from the illuminating system according to image information; and

a projection system that projects image light formed on a light emission surface of the liquid crystal light valve;

wherein the illumination system includes;

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes and illuminates the plurality of partial light emitted from the light dividing element on a light incidence surface of the liquid crystal light valve;

and wherein the liquid crystal light valve includes;

a liquid crystal panel;

a first polarizer located on a side of the light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel; and

first and second optical compensating plates that reduce a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the first and second optical compensating plates being located between the liquid crystal panel and the first polarizer or between the liquid crystal panel and the second polarizer.

12. A projector as claimed in claim 11, wherein the liquid crystal panel is in a TN mode.

13. A projector as claimed in claim 11 further comprising a circuit board that supplies signals to the liquid crystal panel.

14. A projector as claimed in claim 11 further comprising a power source that supplies electric power to the liquid crystal panel.

15. A projector as claimed in claim 11, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

16. A projector, comprising:

an illuminating system that emits illumination light;

a color separation system that separates the illumination light emitted from the illumination system into first to third color lights having three color components;

first to third liquid crystal light valves that respectively modulate first to third color lights separated by the color separation system according to image information;

a color synthesizing section that synthesizes image lights formed on light emission surfaces of the first to third liquid crystal valves; and

a projection system that projects synthesized light emitted from the color synthesizing section;

wherein the illumination system includes;

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes and illuminates the plurality of partial light emitted from the light dividing element on a light incidence surface of the liquid crystal light valve;

and wherein each of the first to third liquid crystal light valves includes;

a liquid crystal panel;

a first polarizer located on a side of the light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel; and

first and second optical compensating plates that reduce a change of the contrast dependent on an angle of the illumination light emitted from the illumination optical system and applied onto the liquid crystal light valve from various directions, the first and second optical compensating plates being located between the liquid crystal panel and the first polarizer or between the liquid crystal panel and the second polarizer.

17. A projector as claimed in claim 16, wherein the liquid crystal panel is in a TN mode.

18. A projector as claimed in claim 16 further comprising a circuit board that supplies signals to the liquid crystal panel.

19. A projector as claimed in claim 16 further comprising a power source that supplies electric power to the liquid crystal panel.

20. A projector as claimed in claim 16, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

21. A projector, comprising:

an illuminating system that emits illumination light;

a liquid crystal light valve that modulates light from the illuminating system according to image information; and

a projection system for that projects image light formed on a light emission surface of the liquid crystal light valve;

wherein the liquid crystal light valve includes;

a liquid crystal panel;

a first polarizer located on a side of a light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first optical compensating plate located between the liquid crystal panel and the first polarizer;

a second optical compensating plate located between the liquid crystal panel and the second polarizer;

a first light-transmissive member bonded to the first optical compensating plate, the first light-transmissive member is located separately from the liquid crystal panel and the first polarizer; and

a second light-transmissive member bonded to the second optical compensating plate, the second light-transmissive member is located separately from the liquid crystal panel and the second polarizer.

22. A projector as claimed in claim 21, wherein the illuminating system includes:

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes the plurality of partial light emitted from the light dividing element on the light incidence surface of the liquid crystal light valve.

23. A projector as claimed in claim 21, wherein the liquid crystal panel is in a TN mode.

24. A projector as claimed in claim 21, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

25. A projector as claimed in claim 21 further comprising a circuit board that supplies signals to the liquid crystal panel.

26. A projector as claimed in claim 21 further comprising a power source that supplies electric power to the liquid crystal panel.

27. A projector comprising:

an illuminating system that emits illumination light;

a color separation system that separates the illumination light emitted from the illumination system into first to third color lights having three color components;

first to third liquid crystal light valves that respectively modulate first to third color lights separated by the color separation system according to image information;

a color synthesizing section that synthesizes image lights formed on light emission surfaces of the first to third liquid crystal valves; and

a projection system that projects synthesized light emitted from the color synthesizing section;

wherein each of the first to third liquid crystal light valves includes;

a liquid crystal panel;

a first polarizer located on a side of a light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first optical compensating plate located between the liquid crystal panel and the first polarizer;

a second optical compensating plate located between the liquid crystal panel and the second polarizer;

a first light-transmissive member bonded to the first optical compensating plate, the first light-transmissive member is located separately from the liquid crystal panel and the first polarizer; and

a second light-transmissive member bonded to the second optical compensating plate, the second light-transmissive member is located separately from the liquid crystal panel and the second polarizer.

28. A projector as claimed in claim 27, wherein the illuminating system includes:

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes the plurality of partial light emitted from the light dividing element on the light incidence surface of the liquid crystal light valve.

29. A projector as claimed in claim 27, wherein the liquid crystal panel is in a TN mode.

30. A projector as claimed in claim 27, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

31. A projector as claimed in claim 27 further comprising a circuit board that supplies signals to the liquid crystal panel.

32. A projector as claimed in claim 27 further comprising a power source that supplies electric power to the liquid crystal panel.

33. A projector, comprising:

an illuminating system that emits illumination light;

a liquid crystal light valve that modulates light from the illuminating system according to image information; and

a projection system for that projects image light formed on a light emission surface of the liquid crystal light valve;

wherein the liquid crystal light valve includes;

a liquid crystal panel;

a first polarizer located on a side of a light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first and second optical compensating plates located between the liquid crystal panel and the first polarizer or between the liquid crystal panel and the second polarizer;

a first light-transmissive member bonded to the first optical compensating plate, the first light-transmissive member is located separately from the liquid crystal panel, the first polarizer and the second polarizer; and

a second light-transmissive member bonded to the second optical compensating plate, the second light-transmissive member is located separately from the liquid crystal panel, the first polarizer and the second polarizer.

34. A projector as claimed in claim 33, wherein the illuminating system includes:

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes the plurality of partial light emitted from the light dividing element on the light incidence surface of the liquid crystal light valve.

35. A projector as claimed in claim 33, wherein the liquid crystal panel is in a TN mode.

36. A projector as claimed in claim 33, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

37. A projector as claimed in claim 33 further comprising a circuit board that supplies signals to the liquid crystal panel.

38. A projector as claimed in claim 33 further comprising a power source that supplies electric power to the liquid crystal panel.

39. A projector, comprising:

an illuminating system that emits illumination light;

a color separation system that separates the illumination light emitted from the illumination system into first to third color lights having three color components;

first to third liquid crystal light valve that respectively modulate the first to third color lights separated by the color separation system according to image information;

a color synthesizing section that synthesizes image lights formed on light emission surfaces of the first to third liquid crystal valves; and

a projection system that projects synthesized light emitted from the color synthesizing section;

wherein each of the first to third liquid crystal light valves includes;

a liquid crystal panel;

a first polarizer located on a side of a light incidence surface of the liquid crystal panel;

a second polarizer located on a side of the light emission surface of the liquid crystal panel;

a first and second optical compensating plates located between the liquid crystal panel and the first polarizer or between the liquid crystal panel and the second polarizer;

a first light-transmissive member bonded to the first optical compensating plate, the first light-transmissive member is located separately from the liquid crystal panel, the first polarized and the second polarized; and

a second light-transmissive member bonded to the second optical compensating plate, the second light-transmissive member is located separately from the liquid crystal panel, the first polarizer and the second polarizer.

40. A projector as claimed in claim 39, wherein the illuminating system includes:

a light source device that emits a nearly parallel light;

a light dividing element that divides the light emitted from the light source device into a plurality of partial light; and

a superimposing lens that superimposes the plurality of partial light emitted from the light dividing element on the light incidence surface of the liquid crystal light valve.

41. A projector as claimed in claim 39, wherein the liquid crystal panel is in a TN mode.

42. A projector as claimed in claim 39, wherein the compensating plate includes a polymer layer in which the angle of inclination of an optical axis varies in the direction of the thickness.

43. A projector as claimed in claim 39 further comprising a circuit board that supplies signals to the liquid crystal panel.

44. A projector as claimed in claim 39 further comprising a power source that supplies electric power to the liquid crystal panel.