Imaging apparatus for increased color gamut using dual spatial light modulators

• US 6,736,514 B2
• Filed: 06/21/2002
• Issued: 05/18/2004
• Est. Priority Date: 06/21/2002
• Status: Expired due to Term

• Current Assignee: IMAX Corporation
• Original Assignee: Eastman Kodak Company
• Inventors: Horvath, Louis S., Zolla, Robert J., Roddy, James E.
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): SEVER, ANDREW T
• Application Number:
  US10/177,513
• Publication Number:
  US 20030234911A1
• Time in Patent Office: 697 Days
• Field of Search: 353/30, 353/31, 353/32, 353/33, 353/34, 353/20, 353/7, 353/8, 353/73, 353/81, 353/82, 353/122, 352/42, 352/66
• US Class Current: 353/31
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• 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
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A display apparatus (10) for projection of a color image from digital data onto a surface (140) comprises a first modulation system which provides a first modulated beam. The first modulation system comprises a first spatial light modulator for modulating a first incident light beam in order to form the first modulated beam according to the digital data; a first light source provides a first color beam as the first incident light beam; and a second light source provides a second color beam as the first incident light beam. A second modulation system provides a second modulated beam. The second modulation system comprises a second spatial light modulator for modulating a second incident light beam in order to form the second modulated beam according to the digital data; a third light source provides a third color beam as the second incident light beam; and a fourth light source provides a fourth color beam as the second incident light beam. An optical combiner (30) directs the first modulated beam and the second modulated beam for projection onto the surface by a projection lens.

Claims

1. A display apparatus for projection of a color image from digital data onto a surface comprising:

(a) a first modulation system for providing a first modulated beam, said first modulation system comprising;

(a1) a first spatial light modulator for modulating a first incident light beam in order to form said first modulated beam according to said digital data;

(a2) a first light source for providing a first color beam as said first incident light beam;

(a3) a second light source for providing a second color beam as said first incident light beam;

(b) a second modulation system for providing a second modulated beam, said second modulation system comprising;

(b1) a second spatial light modulator for modulating a second incident light beam in order to form said second modulated beam according to said digital data;

(b2) a third light source for providing a third color beam as said second incident light beam;

(b3) a fourth light source for providing a fourth color beam as said second incident light beam; and

(c) an optical combiner for directing said first modulated beam and said second modulated beam for projection onto the surface by a projection lens.

2. A projection apparatus according to claim 1 further comprising an integrating bar for uniformizing said first light source.

3. A projection apparatus according to claim 1 further comprising an integrating tunnel for uniformizing said first light source.

4. The display apparatus of claim 1 wherein said first spatial light modulator is a reflective liquid crystal display device.

5. The display apparatus of claim 1 wherein said first spatial light modulator is a transmissive liquid crystal display device.

6. The display apparatus of claim 1 wherein said first spatial light modulator is a digital micromirror device.

7. The display apparatus of claim 1 wherein said first light source and said second light source are selected from the group consisting of red, green, blue, blue-green, and yellow-green light sources.

8. The display apparatus of claim 1 wherein said optical combiner comprises a dichroic surface.

9. The display apparatus of claim 1 wherein said optical combiner is a dichroic prism.

10. The display apparatus of claim 1 wherein said first light source comprises a laser.

11. The display apparatus of claim 1 wherein said first light source comprises an LED.

12. The display apparatus of claim 1 further comprising an optical shutter in the path of said first light source.

13. The display apparatus of claim 1 wherein said first modulation system further comprises a lenslet array for uniformizing said first incident light beam.

14. The display apparatus of claim 1 wherein said first spatial light modulator modulates said first incident light beam during the same time intervals as said second spatial light modulator modulates said second incident light beam.

15. The display apparatus of claim 1 wherein, during a periodically repeating time interval, only one of first spatial light modulator or second spatial light modulator is modulating.

16. The display apparatus of claim 1 wherein said optical combiner directs said first modulated beam and said second modulated beam onto a common optical axis for projection.

17. A projection apparatus according to claim 1 further comprising an analyzer ahead of said projection lens.

18. A projection apparatus according to claim 1 wherein said optical combiner comprises a dichroic surface.

19. A projection apparatus according to claim 1 wherein said first modulation system comprises a polarizing beamsplitter for providing said first incident light beam having a predetermined polarization state.

20. A projection apparatus according to claim 1 wherein said first modulation system comprises a wiregrid polarizing beamsplitter for providing said first incident light beam having a predetermined polarization state.

21. A projection apparatus according to claim 1 wherein said first modulation system comprises a McNeille polarizing beamsplitter for providing said first incident light beam having a predetermined polarization state.

22. A projection apparatus according to claim 1 wherein said first modulation system further comprises a dichroic combiner for directing said first color beam and said second color beam to said first spatial light modulator.

23. A display apparatus for projection of a color image from digital data onto a surface comprising:

(a) a first modulation system for providing a first modulated beam, said first modulation system comprising;

(a1) a first spatial light modulator for modulating a first incident light beam in order to form said first modulated beam according to said digital data;

(a2) a red light source for providing, during a first periodically repeated interval, a red color beam as said first incident light beam;

(a3) a green light source for providing, during a second periodically repeated interval, a green color beam as said first incident light beam;

(b) a second modulation system for providing a second modulated beam, said second modulation system comprising;

(b1) a second spatial light modulator for modulating a second incident light beam in order to form said second modulated beam according to said digital data;

(b2) a blue-green light source for providing, during said first periodically repeated interval, a blue-green color beam as said second incident light beam;

(b3) a blue light source for providing, during said second periodically repeated interval, a blue color beam as said second incident light beam;

(c) wherein said first periodically repeated interval and said second periodically repeated interval alternate and do not overlap; and

(d) an optical combiner for directing said first modulated beam and said second modulated beam for projection onto the surface by a projection lens.

24. A display apparatus for projection of a color image from digital data onto a surface comprising:

(a) a first modulation system for providing a first modulated beam, said first modulation system comprising;

(a1) a first spatial light modulator for modulating a first incident light beam in order to form said first modulated beam according to said digital data;

(a2) a red light source for providing, during a first periodically repeated interval, a red color beam as said first incident light beam;

(a3) a green light source for providing, during a third periodically repeated interval, a green color beam as said first incident light beam;

(b) a second modulation system for providing a second modulated beam, said second modulation system comprising;

(b1) a second spatial light modulator for modulating a second incident light beam in order to form said second modulated beam according to said digital data;

(b2) a blue-green light source for providing, during a second periodically repeated interval, a blue-green color beam as said second incident light beam;

(b3) a blue light source for providing, during a fourth periodically repeated interval, a blue color beam as said second incident light beam;

(c) wherein said first, second, third, and fourth periodically repeated intervals are sequential and do not overlap; and

(c) an optical combiner for directing said first modulated beam and said second modulated beam for projection onto the surface by a projection lens.

25. A method for projecting a color image from digital data onto a surface, the method comprising:

(a) forming a first modulated beam by;

(a1) providing a first color beam from a first light source;

(a2) providing a second color beam from a second light source;

(a3) in a repeated sequence, alternately directing said first color beam and said second color beam to a first spatial light modulator as a first incident light beam, said first spatial light modulator modulating said first incident light beam as an array of pixels to form said first modulated beam;

(b) forming a second modulated beam by;

(b1) providing a third color beam from a third light source;

(b2) providing a fourth color beam from a fourth light source;

(b3) in a repeated sequence, alternately directing said third color beam and said fourth color beam to a second spatial light modulator as a second incident light beam, said second spatial light modulator modulating said second incident light beam as an array of pixels to form said second modulated beam; and

(c) combining said first modulated beam and said second modulated beam to form an output beam and projecting said output beam onto the surface in order to form the color image.

26. A method for projecting a color image according to claim 25 wherein said first modulated beam and said second modulated beam are alternated to form said output beam.

27. A method for projecting a color image according to claim 25 wherein the transition between directing said first color beam and said second color beam to said first spatial light modulator is substantially simultaneous with the transition between directing said third color beam and said fourth color beam to said second spatial light modulator.

28. A method for projecting a color image according to claim 25 wherein the step of combining said first and second modulated beams comprises the step of combining said first and second modulated beams on a single output axis.

29. A method for projecting a color image according to claim 25 wherein the step of providing a first color beam comprises the step of providing a laser beam.

30. A method for projecting a color image according to claim 25 wherein said first spatial light modulator is an LCD.

31. A method for displaying color motion picture content wherein the video camera has a predetermined sampling rate comprising:

(a) alternately directing, onto a first spatial light modulator, a first color beam from a first light source and a second color beam from a second light source;

(b) alternately directing, onto a second spatial light modulator, a third color beam from a third light source and a fourth color beam from a fourth light source; and

(c) modulating, in a synchronous manner at a modulation rate, said first spatial light modulator and said second spatial light modulator, wherein said modulation rate is out of phase with said predetermined sampling rate.

32. A method for minimizing flicker in a digital projection system that modulates, in a display sequence, a first, a second, a third, and a fourth color, the method comprising the steps of:

(a) arranging said first, second, third, and fourth colors in a luminance sequence in order of highest, second highest, third highest, and fourth highest relative luminance value; and

(b) ordering said display sequence according to said luminance sequence so that said color corresponding to said third highest relative luminance value is modulated immediately following said color corresponding to said highest relative luminance value in said sequence.

33. A method for minimizing flicker in a digital projection system according to claim 32 wherein the step of ordering said display sequence further arranges that said color corresponding to said second highest relative luminance value is modulated immediately following said color corresponding to said third highest relative luminance value in said sequence.