Method and apparatus for increasing color gamut of a display

• US 6,648,475 B1
• Filed: 05/20/2002
• Issued: 11/18/2003
• Est. Priority Date: 05/20/2002
• Status: Expired due to Term

• Current Assignee: IMAX Corporation
• Original Assignee: Eastman Kodak Company
• Inventors: Zolla, Robert J., Roddy, James E., Markis, William R.
• Primary Examiner(s): Dowling, William
• Application Number:
  US10/151,742
• Publication Number:
  US 20030214633A1
• Time in Patent Office: 547 Days
• Field of Search: 353/31, 353/33, 353/37, 353/94, 349/8, 348/742, 348/743, 348/750, 348/751, 348/754, 348/757
• US Class Current: 353/31
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3158 for controlling the spectrum
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A method and projection system (10) for increasing the color gamut of images projected onto a display surface (140) by using four or more light sources (12), where the light sources (12) are selected for high brightness and narrow wavelength characteristics and are selected from optimal wavelengths for color gamut expansion. Light sources (12) for large-scale projection environments are preferably lasers. Smaller systems may employ LEDs or other relatively saturated, relatively bright light sources (12).

Claims

1. A color projection system comprising:

(a) a first light source for providing a first color beam;

(b) a first spatial light modulator for modulating said first color beam to provide a first modulated color beam on a first optical axis;

(c) a second light source for providing a second color beam;

(d) a second spatial light modulator for modulating said second color beam to provide a second modulated color beam on a second optical axis;

(e) a third light source for providing a third color beam for transmission through a first color combiner;

(f) a third spatial light modulator for modulating said third color beam to provide a third modulated color beam;

(g) a fourth light source for providing a fourth color beam for reflection by said first color combiner;

(h) a fourth spatial light modulator for modulating said fourth color beam to provide a fourth modulated color beam;

(i) a polarizing beamsplitter for combining said third and fourth modulated color beams onto a third optical axis;

(j) a second color combiner for combining the light on said first, second, and third optical axes to form a multicolor modulated beam; and

(k) a projection system for projecting said multicolor modulated beam.

2. A color projection system as in claim 1 wherein said first, second, third, and fourth spatial light modulators are reflective LCDs.

3. A color projection system as in claim 1 wherein said first, second, third, and fourth spatial light modulators are transmissive LCDs.

4. A color projection system as in claim 1 wherein said polarizing beamsplitter is a wire grid beamsplitter.

5. A color projection system as in claim 1 wherein said first, second, third, and fourth spatial light modulators are gated light valves.

6. A color projection system as in claim 1 wherein said first, second, third, and fourth spatial light modulators are electro-optic modulators combined with polygon scanners.

7. A color projection system as in claim 1 wherein said first, second, third, and fourth light sources are red, green, yellow-green, blue-green, or blue lasers.

8. A color projection system as in claim 1 wherein said first, second, third, and fourth light sources are selected from the group comprised of a red LED array, green LED array, blue-green LED array, yellow-green LED array, and blue LED array.

9. A color projection system as in claim 1 wherein said first, second, third, and fourth light sources are selected from a group comprised of laser, LED array, filtered xenon lamp, and tungsten lamp.

10. A color projection system as in claim 1 wherein said first color combiner is a dichroic combiner.

11. A color projection system as in claim 1 wherein said second color combiner is an X-prism.

12. A color projection system as in claim 1 wherein said second color combiner is a Philips prism.

13. A color projection system comprising:

(a) a first light source for providing a first color beam;

(b) a second light source for providing a second color beam;

(c) a third light source for providing a third color beam;

(d) a fourth light source for providing a fourth color beam;

(e) a color combiner for combining said first, second, third, and fourth color beams onto a common axis to form an illumination beam;

(f) a spatial light modulator for modulating said illumination beam to provide a modulated color beam; and

(g) a projection system for projecting said modulated color beam.

14. A color projection system according to claim 13 wherein said first light source comprises a laser.

15. A color projection system according to claim 13 wherein said first light source comprises an LED array.

16. A color projection system according to claim 13 wherein said color combiner comprises a dichroic combiner.

17. A color projection system according to claim 13 wherein said spatial light modulator is a reflective LCD.

18. A color projection system according to claim 13 wherein said spatial light modulator is a transmissive LCD.

19. A color projection system according to claim 13 wherein said spatial light modulator is digital micromirror device.

20. A color projection system according to claim 13 wherein said spatial light modulator is a gated light valve.

21. A color projection system according to claim 13 wherein said spatial light modulator is an acousto-optical device.

22. A color projection system according to claim 13 further comprising a first shutter for controllably shuttering light from said first light source.

23. A color projection system according to claim 13 wherein said first shutter is an acousto-optical modulator.

24. A color projection system according to claim 13 further comprising a uniformizer for homogenizing said illumination beam.

25. A color projection system comprising:

(a) a first light source for providing a first color beam and a first modulator for modulating said first color beam to form a first modulated beam;

(b) a second light source for providing a second color beam and a second modulator for modulating said second color beam to form a second modulated beam;

(c) a third light source for providing a third color beam and a third modulator for modulating said third color beam to form a third modulated beam;

(d) a fourth light source for providing a fourth color beam and a fourth modulator for modulating said fourth color beam to form a fourth modulated beam;

(e) a color combiner for combining said first, second, third, and fourth modulated beams onto a common axis to form an illumination beam; and

(f) a spinning polygon mirror for directing said illumination beam toward a projection system for projecting said modulated color beam toward a display surface.

26. A color projection system according to claim 25 wherein said first light source comprises a laser.

27. A color projection system according to claim 25 wherein said first light source comprises an LED array.

28. A color projection system according to claim 25 wherein said color combiner comprises a dichroic combiner.

29. A color projection system according to claim 25 wherein said first modulator is an acousto-optical modulator.

30. A color projection system according to claim 25 wherein said first modulator is an electro-optical modulator.

31. A color projection system comprising:

(a) a first light source for providing a first color beam;

(b) a first spatial light modulator for modulating said first color beam to provide a first modulated color beam on a first optical axis;

(c) a second light source for providing a second color beam;

(d) a second spatial light modulator for modulating said second color beam to provide a second modulated color beam on a second optical axis;

(e) a third light source for providing a third color beam;

(f) a third spatial light modulator for modulating said third color be am to provide a third modulated color beam;

(g) a fourth light source for providing a fourth color beam;

(h) a fourth spatial light modulator for modulating said fourth color beam to provide a fourth modulated color be am;

(i) a first color combiner for combining said third and fourth modulated color beams onto a third optical axis;

(j) a second color combiner for combining the light on said first, second, and third optical axes to form a multicolor modulated beam; and

(k) a projection system for projecting said multicolor modulated beam toward a display surface.

32. A color projection system as in claim 31 wherein said first color combiner is a dichroic combiner.

33. A color projection system as in claim 31 wherein said second color combiner is an X-prism.

34. A color projection system as in claim 31 wherein said second color combiner is a Philips prism.

35. A color projection system as in claim 31 wherein said first spatial light modulator is a DMD.

36. A color projection system as in claim 31 wherein said first spatial light modulator is a transmissive LCD.

37. A color projection system comprising:

(a) a first light source for providing a first color beam;

(b) a first spatial light modulator for modulating said first color beam to provide a first modulated color beam on a first optical axis;

(c) a second light source for providing a second color beam;

(d) a second spatial light modulator for modulating said second color beam to provide a second modulated color beam on a second optical axis;

(e) a third light source for providing a green color beam for transmission through a first color combiner, said green color beam having p-polarity with respect to a second color combiner;

(f) a third spatial light modulator for modulating said green color beam to provide a green modulated color beam;

(g) a fourth light source for providing a blue-green color beam for reflection by said first color combiner, said blue-green color beam having s-polarity with respect to said second color combiner;

(h) a fourth spatial light modulator for modulating said blue-green color beam to provide a blue-green modulated color beam;

(i) a polarizing beamsplitter for combining said green and said blue-green modulated color beams onto a third optical axis;

(j) said second color combiner combining the light on said first, second, and third optical axes to form a multicolor modulated beam; and

(k) a projection system for projecting said multicolor modulated beam.

38. A method for projecting a color image, comprising:

(a) providing a first color beam from a first light source;

(b) providing a second color beam from a second light source;

(c) providing a third color beam from a third light source;

(d) providing a fourth color beam from a fourth light source;

(e) directing said first, second, third, and fourth color beams onto a common axis to form an illumination beam;

(f) modulating said illumination beam at a spatial light modulator to provide a modulated beam; and

(g) projecting said modulated beam toward a display surface.

39. A method for projecting a color image according to claim 38 further comprising the step of uniformizing said illumination beam.

40. A method for projecting a color image according to claim 38 wherein said first light source is a laser.

41. A method for projecting a color image according to. claim 38 wherein the step of directing said first, second, third, and fourth color beams onto a common axis uses a dichroic combiner.

42. A method for projecting a color image according to claim 38 wherein the step of directing said first, second, third, and fourth color beams onto a common axis comprises the step of combining said third and fourth color beams onto an intermediate axis, then directing said intermediate axis toward said common axis.

43. A method for projecting a color image according to claim 38 wherein said spatial light modulator is a reflective LCD.

44. A method for projecting a color image according to claim 38 wherein the step of providing said third color beam occurs during a first time period and the step of providing said fourth color beam occurs during a second time period and wherein said first and second time periods are distinct.

45. A method for projecting a color image according to claim 38 wherein the step of providing said first color beam further comprises the step of operating a shutter.

46. A method for projecting a color image, comprising:

(a) providing a first color beam from a first light source;

(b) providing a second color beam from a second light source;

(c) providing a green color beam from a green light source, said green color beam having p-polarity with respect to a color combiner;

(d) providing a blue-green color beam from a blue-green light source, said blue-green color beam having s-polarity with respect to said color combiner;

(e) directing said first, second, third, and fourth color beams onto a common axis to form an illumination beam;

(f) modulating said illumination beam at a spatial light modulator to provide a modulated beam; and

(g) projecting said modulated beam toward a display surface.