Laser projection display system

• US 6,594,090 B2
• Filed: 08/27/2001
• Issued: 07/15/2003
• Est. Priority Date: 08/27/2001
• Status: Expired due to Term

• Current Assignee: IMAX Theatres International Limited (IMAX Corporation)
• Original Assignee: Eastman Kodak Company
• Inventors: Kurtz, Andrew F., Kruschwitz, Brian E.
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): Spector, David N.
• Application Number:
  US09/940,196
• Publication Number:
  US 20030039036A1
• Time in Patent Office: 687 Days
• Field of Search: 359/622, 359/634, 359/707, 353/31, 372/108, 345/88
• US Class Current: 359/707
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0933 Systems for active beam shaping by rapid movement of an element
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G02B 27/48 Laser speckle optics
• 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 9/3132 using one-dimensional electronic spatial light modulators
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

A display apparatus, includes a laser light source for emitting a light beam; a beam expander for expanding the light beam; a spatial light modulator; beam shaping optics for shaping the expanded laser beam to provide uniform illumination of the spatial light modulator, the beam shaping optics including a fly'"'"'s eye integrator having an array of lenslets; and a moving diffuser located in the laser beam between the laser light source and the spatial light modulator.

Claims

1. Display apparatus, comprising:

(a) a laser light source for emitting a light beam;

(b) a beam expander for expanding the light beam;

(c) a spatial light modulator;

(d) beam shaping optics for shaping the expanded laser beam to provide uniform illumination of the spatial light modulator, the beam shaping optics including a fly'"'"'s eye integrator having an array of lenslets; and

(e) a moving diffuser located in the laser beam between the laser light source and the spatial light modulator.

2. The display apparatus claimed in claim 1, wherein the moving diffuser is located between the laser light source and the fly'"'"'s eye integrator.

3. The display apparatus claimed in claim 2, further comprising:

a second diffuser located between the fly'"'"'s eye integrator and the spatial light modulator.

4. The display apparatus claimed in claim 3 wherein the second diffuser is a moving diffuser.

5. The display apparatus claimed in claim 4 wherein both the moving diffusers are moved under the influence of the same motion imparting means.

6. The display apparatus claimed in claim 1, wherein the moving diffuser includes a diffuser plate and a motor linked to the diffuser plate for providing oscillatory motion of the diffuser plate in a plane perpendicular to the laser beam.

7. The display apparatus claimed in claim 1, wherein the moving diffuser includes a diffuser plate mounted in a rotating wheel such that the diffuser rotates about an axis parallel to the laser beam.

8. The display apparatus claimed in claim 1, wherein the spatial light modulator comprises a two-dimensional array of modulator elements.

9. The display apparatus claimed in claim 8, wherein the spatial light modulator is a liquid crystal light valve.

10. The display apparatus claimed in claim 8, wherein the modulator elements are micromirrors.

11. The display apparatus claimed in claim 1, wherein the spatial light modulator comprises a one-dimensional array of modulator elements disposed in a line, and further comprising a scanner for generating a two-dimensional image.

12. The display apparatus claimed in claim 11, wherein the modulator elements are electrically-controllable diffraction gratings.

13. The display apparatus claimed in claim 1, further comprising a projection lens for producing an image on a display screen.

14. The display apparatus claimed in claim 1, wherein the laser light source is characterized by a coherence length, and wherein the beam expander comprises an array of partially reflecting mirrors to split the light beam into N beamlets, wherein adjacent beamlets propagate paths through the array of partially reflecting mirrors that differ by at least the coherence length;

and wherein the beam shaping optics shapes the N beamlets to provide uniform illumination of the spatial light modulator.

15. The display apparatus claimed in claim 14, wherein the array of lenslets comprises M×

N lenslets, wherein M is an integer.

16. The display apparatus claimed in claim 14, wherein the moving diffuser is located before the fly'"'"'s eye integrator.

17. The display apparatus claimed in claim 15 wherein a second diffuser is located between the fly'"'"'s eye integrator and the spatial light modulator.

18. The display apparatus claimed in claim 16 wherein the second diffuser is a moving diffuser.

19. The display apparatus claimed in claim 18 wherein both moving diffusers are moved under the influence of the same motion imparting means.

20. The display apparatus claimed in claim 14, wherein the moving diffuser includes a diffuser plate and a motor linked to the diffuser plate for providing oscillatory motion of the diffuser plate in a plane perpendicular to the laser beam.

21. The display apparatus in claim 14, wherein the moving diffuser includes a diffuser plate mounted in a rotating wheel such that the diffuser rotates about an axis parallel to the laser beam.

22. The display apparatus in claim 14, wherein the spatial light modulator comprises a two-dimensional array of modulator elements.

23. The display apparatus in claim 22, wherein the spatial light modulator is a liquid crystal light valve.

24. The display apparatus in claim 21, wherein the modulator elements are micromirrors.

25. The display apparatus in claim 14, wherein the spatial light modulator comprises a one-dimensional array of modulator elements disposed in a line, the display apparatus further comprising a scanner for generating a two-dimensional image.

26. The display apparatus in claim 25, wherein the modulator elements are electrically-controllable diffraction gratings.

27. The display apparatus in claim 14, further comprising a projection lens for producing an image on a display screen.

28. The display apparatus claimed in claim 1, wherein the display apparatus is a color display apparatus.

29. The display apparatus claimed in claim 28, wherein the display apparatus is a three channel color display apparatus.

30. The display apparatus claimed in claim 29, wherein the laser light source comprises a single laser oscillator and an optical parametric oscillator with nonlinear optical elements to simultaneously generate red, green and blue laser beams.

31. The display apparatus claimed in claim 29, wherein the laser light source comprises separate lasers to generate red, green and blue light beams.

32. The display apparatus claimed in claim 29, wherein the laser light source comprises a single laser for generating a white light beam that is split into three colors prior to passing through three separate light valves, and is recombined subsequent to the light valves.

33. The display apparatus claimed in claim 28, wherein the color display is a color sequential display having a white light laser and further comprising a filter wheel having red, green and blue filter sequentially produce red, green and blue colored frames.

34. The display apparatus claimed in claim 28, wherein the color display is a color sequential display having a laser that sequentially emits red, green and blue colored light.

35. The display apparatus claimed in claim 2, wherein the diffuser is located at a plane conjugate to the spatial light modulator.