Light source device including a planar light source having a single, substantially continuous light emission area and display device incorporating the light source device

• US 6,882,379 B1
• Filed: 06/04/1999
• Issued: 04/19/2005
• Est. Priority Date: 06/05/1998
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yokoyama, Osamu, Shimoda, Tatsuya, Miyashita, Satoru
• Primary Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/485,153
• Time in Patent Office: 2,146 Days
• Field of Search: 349/61, 349/62, 349/68, 349/70, 349/5, 349/6, 349/98, 353/20
• US Class Current: 349/61
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/1053 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/149 using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A red light source comprising an array of LEDs 102R that emit light of a red color, a green light source comprising an array of LEDs 102G that emit light of a green color, and a blue light source comprising an array of LEDs 102B that emit light of a blue color are deployed about the periphery of a dichroic prism 101. A liquid crystal display element is illuminated by a light source device configured such that the light from the respective light sources is synthesized into white light by the dichroic prism, and projection type liquid crystal display devices and the like are configured.

Claims

1. A light source device, comprising:

a first light source for emitting first light of a first color;

a second light source for emitting second light of a second color;

a third light source for emitting third light of a third color;

a first polarization converter for aligning a polarization direction of said first light by converting one polarization component to the other polarization component;

a second polarization converter for aligning a polarization direction of said second light by converting one polarization component to the other polarization component;

a third polarization converter for aligning a polarization direction of said third light by converting one polarization component to the other polarization component; and

a color synthesizing optical system for synthesizing said first, second and third light of which the polarization directions are respectively aligned by said first, second, and third polarization converters,

wherein the first polarization converter comprises a first reflecting polarizer positioned between the first light source and the color synthesizing optical system, and a first reflector provided inside the first light source so that polarized light that is returned to the first light source is reflected by the first reflector toward the first reflecting polarizer,

the second polarization converter comprises a second reflecting polarizer positioned between the second light source and the color synthesizing optical system, and a second reflector provided inside the second light source so that polarized light that is returned to the second light source is reflected by the second reflector toward the second reflecting polarizer,

the third polarization converter comprises a third reflecting polarizer positioned between the third light source and the color synthesizing optical system, and a third reflector provided inside the third light source so that polarized light that is returned to the third light source is reflected by the third reflector toward the third reflecting polarizer.

2. The light source device according to claim 1, characterized in that said first color is a color in a region from orange to red, said second color is a color in a region from green to yellow-green, and said third color is a color in a blue region.

3. The light source device according to claim 1, characterized in that said color synthesizing optical system is a dichroic prism.

4. The light source device according to claim 1, characterized in that said first, second, and third light sources are light emitting diodes.

5. The light source device according to claim 4, characterized in that lenses are deployed between said first, second, and third light sources and said color synthesizing optical system.

6. The light source device according to claim 4, characterized in that lens array elements are deployed between said first, second, and third light sources and said color synthesizing optical system.

7. The light source device according to claim 4, characterized in that a plurality of said light emitting diodes are deployed two-dimensionally in said first, second, and third light sources, respectively.

8. The light source device according to claim 1, characterized in that said first, second, and third light sources are flat-panel fluorescent tubes.

9. The light source device according to claim 8, characterized in that prism array elements are deployed between said flat-panel fluorescent tubes and said color synthesizing optical system.

10. The light source device according to claim 8, characterized in that said prism array elements are each configured from two mutually perpendicular prism arrays.

11. The light source device according to claim 1, characterized in that said first, second, and third light sources are flat-panel electroluminescent elements.

12. The light source device according to claim 11, characterized in that said electroluminescent elements are organic electroluminescent elements having organic thin films as light emitting layers.

13. The light source device according to claim 11, characterized in that said organic electroluminescent elements comprise optical resonators in light emitting layer structures thereof.

14. The light source device according to claim 1, characterized in that said first, second, and third light sources light simultaneously.

15. The light source device according to claim 1, characterized in that said first, second, and third light sources repeatedly light in order.

16. A display device having:

a light modulating element; and

a light source device according to claim 1;

characterized in that;

light from said light source device is modulated in said light modulating element; and

light so modulated is magnified by a projection lens and displayed.

17. The display device according to claim 16, characterized in that:

said light modulating element is a transmissive type liquid crystal element;

said light source device is deployed opposite one face of said liquid crystal element; and

images formed on said liquid crystal element are magnified by said projection lens and displayed.

18. The display device according to claim 17, characterized in that magnified virtual images of images displayed by a liquid crystal display element are viewed.

19. The display device according to claim 17, characterized in that color filters are formed in pixels configuring said liquid crystal display element.

20. The display device according to claim 16, characterized in that said light modulating element is a reflecting type light modulating element, and said light source device is deployed opposite reflecting surface of said light modulating element.

21. The display device according to claim 16, characterized in that:

said light modulating element forms, with time division, a first color component image, a second color component image, and a third color component image;

said first light source in said light source device is lit during time interval wherein said first color component image is being formed, said second light source in said light source device is lit next during time interval wherein said second color component image is being formed, and said third light source in said light source device is lit next during time interval wherein said third color component image is being formed; and

a color image is displayed by sequential display of said first, second, and third color components in said light modulating element, and by sequential lighting of said first, second, and third light sources corresponding to those sequential displays.

22. The display device according to claim 16, characterized in that said first color is a color in a region from orange to red, said second color is a color in a region from green to yellow-green, and said third color is a color in a blue region.

23. The display device according to claim 16, characterized in that said color synthesizing optical system is a dichroic prism.

24. The display device according to claim 16, characterized in that said first, second, and third light sources are light emitting diodes.

25. The display device according to claim 24, characterized in that a plurality of said light emitting diodes are deployed two-dimensionally in said first, second, and third light sources, respectively.

26. The display device according to claim 24, characterized in that lenses are deployed between said first, second, and third light sources and said color synthesizing optical system.

27. The display device according to claim 24, characterized in that lens array elements are deployed between said first, second, and third light sources and said color synthesizing optical system.

28. The display device according to claim 16, characterized in that each of said first, second, third light sources is a planar light source.

29. The display device according to claim 16, characterized in that said first, second, and third light source are flat-panel fluorescent tubes.

30. The display device according to claim 29, characterized in that prism array elements are deployed between said flat-panel fluorescent tubes and said color synthesizing optical system.

31. The display device according to claim 29, characterized in that said prism array elements are each configured from two mutually perpendicular prism arrays.

32. The display device according to claim 16, characterized in that said first, second, and third light sources are flat-panel electroluminescent elements.

33. The display device according to claim 32, characterized in that said electroluminescent elements are organic electroluminescent elements having organic thin films as light emitting layers.

34. The display device according to claim 32, characterized in that said organic electroluminescent elements comprise optical resonators in light emitting layer structures thereof.

35. The display device according to claim 16, characterized in that said polarization converter further comprises a quarter-wave film, said quarter-wave film being deployed on sides toward said light sources;

and said reflecting polarizer is deployed on sides toward said color synthesizing optical system element.

36. The display device according to claim 16, characterized in that said first, second and third light sources light simultaneously.

37. The display device according to claim 16, characterized in that said first, second, and third light sources repeatedly light in order.

38. The display device according to claim 16, wherein polarization directions of the polarization components are perpendicular to each other.

39. The display device according to claim 16, wherein rotational directions of the polarization components are opposite to each other.

40. The light source device according to claim 1, wherein polarization directions of the polarization components are perpendicular to each other.

41. The light source device according to claim 1, wherein rotational directions of the polarization components are opposite to each other.

42. The light source device according to claim 1, characterized in that each of said first, second, and third light sources is a planar light source.

43. The light source device according to claim 1, characterized in that said polarization converter further comprises a quarter-wave film, said quarter-wave film being deployed on sides toward said light sources;

and said reflecting polarizer is deployed on sides toward said color synthesizing optical system element.