Illumination system for scrolling color recycling

• US 6,591,022 B2
• Filed: 12/21/2001
• Issued: 07/08/2003
• Est. Priority Date: 12/29/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Dewald, D. Scott
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US10/028,023
• Publication Number:
  US 20020135862A1
• Time in Patent Office: 564 Days
• Field of Search: 359/631, 359/626, 359/636, 359/291, 359/889, 359/237, 353/31, 353/84, 353/94, 353/98, 353/34, 353/70, 353/101, 345/46, 345/83, 345/204, 348/742, 348/751, 348/744, 382/274
• US Class Current: 382/274
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: H04N 9/3117 by using a sequential colour filter producing two or more colours simultaneously, e.g. by creating scrolling colour bands

Abstract

Distortion optics are used to efficiently couple a spiral color wheel and an orthogonal modulator. Light 602 from a light source enters an aperture in a reflective end of a recycling integrator rod 604. The light travels through the rod and exits the end of the rod adjacent a sequential color filter 606, shown as a spiral color wheel. The shape of the light beam 608 exiting the integrator rod 604 is determined by the shape of the exit aperture of the integrating rod 606. The exit aperture of the integrating rod 606 typically is formed by a reflective exit aperture on the exit face. A cross section of the light beam 608 exiting the sequential color filter includes several bands of filtered light, one for each of the filter segments of the color wheel illuminated by the light beam. The curvature of the color bands makes it difficult for a row addressed spatial light modulator to efficiently use the light. Illumination system 600 eliminates or mitigates this problem by distorting the light from the integrating rod to straighten the curved borders between the adjacent filter segments. The light 608 from the sequential color filter 606 is distorted by distortion optics 610, 612 to make the boundaries between the white or primary colored light segments align with the rows of the spatial light modulator 614.

Claims

1. A display system comprising:

a light source for producing a beam of white light along a path;

a sequential color filter receiving said beam of white light to form a filtered beam of light having a first cross section;

a spatial light modulator having a second cross section;

distortion optics on an optical path between said sequential color filter and said spatial light modulator, said distortion optics operable to receive and distort said filtered beam to a filtered beam having a cross section more efficiently coupled to said spatial light modulator than said first cross section; and

a controller electrically connected to said spatial light modulator for providing image data to said spatial light modulator, said spatial light modulator operable to modulate said filtered beam according to said image data.

2. The display system of claim 1, comprising:

a recycling integrator on said path of said white light beam.

3. The display system of claim 1, comprising:

a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section.

4. The display system of claim 1, comprising:

a recycling integrator on said path of said white light beam, said recycling integrator having a reflective exit face with an aperture defining said first cross section.

5. The display system of claim 1, said sequential color filter comprising:

a spiral color wheel.

6. The display system of claim 1, comprising:

a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section; and

said sequential color filter comprising a spiral color wheel, said first cross section having at least one curved side following a boundary between two segments on said spiral color wheel.

7. The display system of claim 6, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters.

8. The display system of claim 6, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters across their entire width.

9. The display system of claim 6, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters and at least one clear filter.

10. The display system of claim 6, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters across their entire width and at least one clear filter across its width.

11. The display system of claim 1, said distortion optics comprising:

a spherical mirror.

12. The display system of claim 1, said distortion optics comprising:

an aspherical mirror.

13. The display system of claim 1, said distortion optics comprising:

a spherical lens.

14. The display system of claim 1, said distortion optics comprising:

an aspherical lens.

15. The display system of claim 1, said distortion optics comprising:

a mirror and lens.

16. The display system of claim 1, said distortion optics distorting a curved image of a boundary between two adjacent filter segments to align with rows of said spatial light modulator such that said distorted image of said boundary is imaged across less of said rows than said undistorted boundary image.

17. A method of illuminating a spatial light modulator, the method comprising:

producing a beam of white light along a path;

sequentially color filtering said beam of white light to form a filtered beam of light having a first cross section;

distorting said filtered beam of light to have a second cross section; and

spatially modulating said distorted beam of light using a spatial light modulator, said distorting operable to improve the alignment of filter boundaries to groups of spatial light modular elements.

18. The method of claim 17, comprising:

recycling light rejected by said sequentially color filtering.

19. The method of claim 17, comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section.

20. The method of claim 17, comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator on said path of said white light beam, said recycling integrator having a reflective exit aperture defining said first cross section.

21. The method of claim 17, said sequentially color filtering comprising:

sequentially color filtering said beam of white light to using a spiral color wheel to form a filtered beam of light having a first cross section.

22. The method of claim 17, comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section; and

said sequentially color filtering comprising sequentially color filtering said beam of white light to using a spiral color wheel, said first cross section having at least one curved side following a boundary between two segments on said spiral color wheel.

23. The method of claim 22, said recycling light comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator having an exit aperture with at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters.

24. The method of claim 22, said recycling light comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator having an exit aperture with at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters across their entire width.

25. The method of claim 22, said recycling light comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator having an exit aperture with at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters and at least one clear filter.

26. The method of claim 22, said recycling light comprising:

recycling light rejected by said sequentially color filtering using a recycling integrator having an exit aperture with at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters across their entire width and at least one clear filter across its width.

27. The method of claim 17, said distorting comprising:

distorting said filtered beam of light to have a second cross section using a spherical mirror.

28. The method of claim 17, said distorting comprising:

distorting said filtered beam of light to have a second cross section using an aspherical mirror.

29. The method of claim 17, said distorting comprising:

distorting said filtered beam of light to have a second cross section using a spherical lens.

30. The method of claim 17, said distorting comprising:

distorting said filtered beam of light to have a second cross section using an aspherical lens.

31. The method of claim 17, said distorting comprising:

distorting said filtered beam of light to have a second cross section using a mirror and lens.

32. The method of claim 17, said distorting comprising:

distorting a curved image of a boundary between two adjacent filter segments to align with rows of said spatial light modulator such that said distorted image of said boundary is imaged across less of said rows than said undistorted boundary image.

33. The method of claim 17, comprising:

modulating said distorted beam of light using said spatial light modulator.

34. The method of claim 17, comprising:

modulating said distorted beam of light using said spatial light modulator; and

focusing said modulated light onto an image plane.

35. A display system comprising:

a light source for producing a beam of white light along a path;

a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section; and

a sequential color filter receiving said beam of white light to form a filtered beam of light having a first cross section, said first cross section having at least one curved side following a boundary between two segments on said sequential color filter;

a spatial light modulator having a second cross section;

distortion optics on an optical path between said sequential color filter and said spatial light modulator, said distortion optics operable to receive and distort said filtered beam to a filtered beam having a cross section more efficiently coupled to said spatial light modulator than said first cross section.

36. The display system of claim 35, comprising:

a controller electrically connected to said spatial light modulator for providing image data to said spatial light modulator, said spatial light modulator operable to modulate said filtered beam according to said image data.

37. The display system of claim 35, comprising:

a recycling integrator on said path of said white light beam.

38. The display system of claim 35, comprising:

a recycling integrator on said path of said white light beam, said recycling integrator having an exit aperture defining said first cross section.

39. The display system of claim 35, comprising:

a recycling integrator on said path of said white light beam, said recycling integrator having a reflective exit face with an aperture defining said first cross section.

40. The display system of claim 35, said sequential color filter comprising:

a spiral color wheel.

41. The display system of claim 35, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters.

42. The display system of claim 35, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three color filters across their entire width.

43. The display system of claim 35, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters and at least one clear filter.

44. The display system of claim 35, said exit aperture having at least two opposite sides shaped to follow said boundary between two segments on said spiral color wheel, said exit aperture sized to allow said white light beam to illuminate at least three primary color filters across their entire width and at least one clear filter across its width.

45. The display system of claim 35, said distortion optics comprising:

a spherical mirror.

46. The display system of claim 35, said distortion optics comprising:

an aspherical mirror.

47. The display system of claim 35, said distortion optics comprising:

a spherical lens.

48. The display system of claim 35, said distortion optics comprising:

an aspherical lens.

49. The display system of claim 35, said distortion optics comprising:

a mirror and lens.

50. The display system of claim 35, said distortion optics distorting a curved image of a boundary between two adjacent filter segments to align with rows of said spatial light modulator such that said distorted image of said boundary is imaged across less of said rows than said undistorted boundary image.