Color recapture for display systems

• US 6,771,325 B1
• Filed: 11/03/2000
• Issued: 08/03/2004
• Est. Priority Date: 11/05/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Penn, Steven M., Dewald, Duane S., Davis, Michael T.
• Primary Examiner(s): Miller, John
• Assistant Examiner(s): Yenke, Brian
• Application Number:
  US09/705,467
• Time in Patent Office: 1,369 Days
• Field of Search: H04/N.912, H04/N.564, H04/N.574, 348/742, 348/743, 348/744, 348/759, 348/760, 348/761, 348/762, 348/771, 359/127, 359/129, 359/130, 359/131, 359/132, 359/226, 359/209, 359/495, 359/588-590, 359/634, 359/636, 345/32, 345/426, 345/427, 353/31, 353/84
• US Class Current: 348/743
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: G03B 21/2066 Reflectors in illumination beam in projection beam G03B21/28
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• 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
• 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
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

A sequential color display system using a white light source (202) to create a full color image projected onto an image plane (214). A dynamic filter (206), typically a series of moving dichroic filters, generates a series of primary colored light beams that are swept across the surface of a spatial light modulator (210). Light rejected by the dynamic filter (206) enters a light recycler (204) and is reapplied to the dynamic filter (206). The light recycler is typically one or more reflective surfaces, including mirrors, baffles, enclosures, lamp reflectors, TIR surfaces, or specially coated material arranged in such a way as to encourage light toward an aperture separating the light recycler (204) and the dynamic filter (206). Typically all three primary colors are produced simultaneously by the dynamic filter (206). The illuminated portion of the dynamic filter (206) is imaged onto the modulator (210) and a controller (216) provides appropriate image data for each portion of the modulator (210) in synchronization with the sweep of the primary color bands across the modulator surface. The primary color bands are modulated by the spatial light modulator (210) and the modulated light is focused by lens (212) onto the image plane (214). The viewer integrates the light arriving at each portion of the image plane (214) over a frame period to provide the perception of a full-color image.

Claims

1. A display system comprising:

a light source for producing a beam of light;

a filter for filtering said beam of light, said filter always having at least two regions having different characteristics in the path of said beam of light, a first region of said filter separating said beam of light into a first color beam of light traveling along a first path, and a remainder beam of light traveling along a second path;

a spatial light modulator on said first path for receiving light traveling along said first path and selectively modulating said light traveling along said first path; and

wherein a portion of said remainder beam of light is incident a second region of said filter and travels along said first path.

2. The display system of claim 1, wherein said remainder beam of light is homogenized before being incident said second region of said filter.

3. The display system of claim 1, comprising an integrator for homogenizing said beam of light.

4. The display system of claim 3, wherein said integrator is a reflective enclosure.

5. The display system of claim 3, wherein said integrator is a glass rod.

6. The display system of claim 3, wherein said integrator is a mirrored glass rod.

7. The display system of claim 3, wherein said integrator is a hollow cylinder.

8. The display system of claim 3, wherein said integrator is a reflective hollow rectangular cylinder.

9. The display system of claim 3, wherein said integrator has a reflective entrance aperture.

10. The display system of claim 3, wherein said integrator has retro-reflective entrance aperture.

11. The display system of claim 3, wherein said integrator has an aspect ratio equal to an aspect ratio of said modulator.

12. The display system of claim 1, wherein light traveling along said first path fills said modulator.

13. The display system of claim 1, wherein said filter transmits said first portion of light along said first path.

14. The display system of claim 1, wherein said filter is a color wheel.

15. The display system of claim 1, wherein said filter is a three color color wheel.

16. The display system of claim 1, said filter comprised of segments to selectively separate a red, green, and blue portion of said light beam.

17. The display system of claim 1, wherein said filter is a three primary color plus white color wheel.

18. The display system of claim 1, said filter comprised of segments to selectively separate a red, green, blue, and white portions of said light beam.

19. The display system of claim 1, wherein said filter is a color wheel having a plurality of filter segments.

20. The display system of claim 1, wherein said filter is a color wheel having a plurality of filter segments arranged in a spiral.

21. The display system of claim 1, comprising:

an homogenizer to homogenize said remainder portion of said beam of light.

22. The display system of claim 21, comprising:

an integrator for homogenizing said beam of light, said integrator separate from said homogenizer.

23. The display system of claim 21, wherein said homogenizer is a fiber-optic bundle.

24. The display system of claim 21, wherein said homogenizer is a prism.

25. A display system comprising:

a light source for producing a beam of light;

an integrator for homogenizing said beam of light;

a filter for filtering said homogenized beam of light, said filter always having at least two regions having different characteristics in the path of said beam of light, said filter separating said homogenized beam of light into a first beam of light traveling along a first path, and a remainder beam of light traveling along a second path;

a spatial light modulator on said first path for receiving light traveling along said first path and selectively modulating said light traveling along said first path; and

wherein said remainder beam re-enters said integrator and is re-transmitted by said integrator to said filter such that a portion of said remainder beam of light is incident a second region of said filter and travels along said first path.

26. The display system of claim 25, wherein said remainder beam of light is re-homogenized by said integrator before being incident said second region of said filter.

27. The display system of claim 25, wherein said integrator is a reflective enclosure.

28. The display system of claim 25, wherein said integrator is a glass rod.

29. The display system of claim 25, wherein said integrator is a mirrored glass rod.

30. The display system of claim 25, wherein said integrator is a hollow cylinder.

31. The display system of claim 25, wherein said integrator is a reflective hollow rectangular cylinder.

32. The display system of claim 25, wherein said integrator has a reflective entrance aperture.

33. The display system of claim 25, further comprising a reflector surrounding an entrance end of said integrator.

34. The display system of claim 25, wherein said integrator has retro-reflective entrance aperture.

35. The display system of claim 25, wherein said integrator has an aspect ratio equal to an aspect ratio of said modulator.

36. The display system of claim 25, wherein light traveling along said first path fills said modulator.

37. The display system of claim 25, wherein said filter transmits said first portion of light along said first path.

38. The display system of claim 25, wherein said filter is a color wheel.

39. The display system of claim 25, wherein said filter is a three color color wheel.

40. The display system of claim 25, said filter comprised of segments to selectively separate a red, green, and blue portion of said light beam.

41. The display system of claim 25, wherein said filter is a three primary color plus white color wheel.

42. The display system of claim 25, said filter comprised of segments to selectively separate a red, green, blue, and white portions of said light beam.

43. The display system of claim 25, wherein said filter is a color wheel having a plurality of filter segments.

44. The display system of claim 25, wherein said filter is a color wheel having a plurality of filter segments arranged in a spiral.

45. A method of producing an image, said method comprising the steps of:

impinging a beam of light on a dynamic filter such that said beam of light impinges on at least two regions of said dynamic filter at all times during operation, a first region of said dynamic filter transmitting a first portion of said beam of light to a spatial light modulator and rejecting a remainder of said beam of light;

modulating said first portion of said beam of light;

impinging a portion of said remainder of said beam of light on a second region of said dynamic filter, said second region of said dynamic filter transmitting a second portion of said remainder of said beam of light;

modulating said second portion of said beam of light; and

focusing said modulated first and second portions of said beam of light on an image plane.

46. The method of claim 45, said step of impinging said beam of light on a first region of a dynamic filter comprising the step of impinging said beam of light on a first region of a rotating color filter.

47. The method of claim 45, said step of impinging said beam of light on a second region of a dynamic filter comprising the step of impinging said beam of light on a second region of a rotating color filter.

48. The method of claim 45, said step of impinging a portion of said remainder of said beam of light on a second region of said dynamic filter further comprising the step of rejecting a second remainder portion, and further comprising the steps of:

impinging said second remainder portion on a third region of a dynamic filter, said third region of said dynamic filter transmitting a third portion of said beam of light;

modulating said third portion of said beam of light; and

focusing said modulated third portion of said beam of light on said image plane.