HIGH EFFICIENCY DIGITAL CINEMA PROJECTION SYSTEM WITH INCREASED ETENDUE

• US 20070273797A1
• Filed: 04/25/2007
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Abandoned Application

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Kircher, James R., Bietry, Joseph R., Silverstein, Barry D.
• Application Number:
  US11/739,775
• Publication Number:
  US 20070273797A1
• Time in Patent Office: Days
• US Class Current: 348/752
• CPC Class Codes: G02B 13/22 Telecentric objectives or lens systems
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/1046 for use with transmissive spatial light modulators
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 3/0087 with index gradient
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• 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 9/315 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

Abstract

A digital cinema projection apparatus having an illumination source with a first etendue value for providing polarized polychromatic light. A first lens element lies in the path of the polarized polychromatic light for forming a substantially telecentric polarized polychromatic light beam. A color separator separates the telecentric polarized polychromatic light beam into at least two telecentric color light beams. At least two transmissive spatial light modulators modulate the two telecentric color light beams. There is an etendue value associated with each spatial light modulator. The etendue value is within 15% or greater than the first etendue value corresponding to the illumination source. A color combiner combines the modulated color beams along a common optical axis, forming a multicolor modulated beam thereby; and a projection lens directs the multicolor modulated beam toward a display surface.

Claims

1. A digital cinema projection apparatus comprising:

a) an illumination source having a first etendue value for providing polarized polychromatic light;

b) a first lens element in the path of the polarized polychromatic light for forming a substantially telecentric polarized polychromatic light beam;

c) a color separator for separating the telecentric polarized polychromatic light beam into at least a first telecentric color light beam and a second telecentric color light beam;

d) a first transmissive spatial light modulator in the path of the first telecentric color light beam and modulating the first telecentric color beam to form a first modulated color beam,

wherein there is a second etendue value associated with the first spatial light modulator, and wherein the second etendue value exceeds the first etendue value;

e) a second transmissive spatial light modulator in the path of the second telecentric color light beam and modulating the second telecentric color beam to form a second modulated color beam,

wherein there is a third etendue value associated with the second spatial light modulator, and wherein the third etendue value exceeds the first etendue value;

f) at least first and second projection lenses for directing at least the first and second modulated color beam toward a display surface

2. The projection apparatus of claim 1 further comprising a first condensing lens for directing the first telecentric color light beam through the first transmissive liquid crystal spatial light modulator.

3. The apparatus of claim 1 wherein the first spatial light modulator has a active surface diagonal of greater than about 5 inches.

4. The apparatus of claim 1 wherein the multicolor modulated beam exceeds 5,000 lumens.

5. The apparatus of claim 1 wherein the first lens element comprises a Fresnel lens.

6. The apparatus of claim 1 further comprising a second lens element in the path of at least one modulated color beam.

7. The apparatus of claim 1 further comprising a first compensator in the path of at least one modulated color beam.

8. The apparatus of claim 7 further comprising a first polarization analyzer disposed between the first compensator and the projection lens.

9. The apparatus of claim 7 further comprising a second compensator in the path of at least one telecentric color light beam.

10. The apparatus of claim 1 further comprising a polarization rotator in the path of at least one modulated color beam.

11. The apparatus of claim 1 further comprising an uniformizer optically coupled to the illumination source.

12. The apparatus of claim 1 wherein the illumination source comprises an element taken from the group consisting of an LED, an LED array, a Xenon lamp, and a Mercury lamp.

13. The apparatus of claim 11 wherein the uniformizer comprises a lenslet array.

14. The apparatus of claim 11 wherein the uniformizer comprises an integrating bar.

15. The apparatus of claim 1 wherein the illumination source further comprises a polarization rotation element for a portion of the illumination.

16. The apparatus of claim 1 further comprising a reflective color filter array that provides color recycling.

17. The apparatus of claim 1 wherein at least one spatial modulator is a transmissive thin-film transistor liquid crystal modulator.

18. The apparatus of claim 17 wherein the thin film transistors are organic thin film transistors.

19. The apparatus of claim 17 wherein the thin film transistors comprise carbon nanotubes.

20. The apparatus of claim 1 wherein the illumination source further comprises a wire grid polarizer.

21. The apparatus of claim 10 wherein the polarization rotator is an absorptive polarizer.

22. The apparatus of claim 10 wherein the polarization rotator is a reflective polarizer.

23. The apparatus of claim 1 further comprising a diffuse reflective polarizer film in the path of the telecentric polarized polychromatic light.

24. The apparatus of claim 1 further comprising a dispersive optical component in the path of the first telecentric color light beam.

25. The apparatus of claim 1 wherein at least one transmissive liquid crystal spatial light modulator has a active surface diagonal of greater than about 10 inches.

26. The apparatus of claim 1 wherein at least one transmissive liquid crystal spatial light modulator is formed on a non-crystalline substrate.

27. The apparatus of claim 1 wherein the color separator further forms a third telecentric color light beam and the apparatus further comprises a third transmissive spatial light modulator in the path of the third telecentric color light beam and modulating the third telecentric color beam to form a third modulated color beam, and;

further comprising a third projection lens for directing the third modulated color beam toward the display surface.

28. The apparatus of claim 1 wherein at least one transmissive liquid crystal spatial light modulator comprises an antireflection coating.

29. The apparatus of claim 1 wherein optical path lengths between the at least two transmissive liquid crystal spatial light modulators and their respective projection lenses differ.

30. The apparatus of claim 10 wherein the polarization rotator comprises a stacked polarizer.

31. The apparatus of claim 1 wherein at least one projection lens is anamorphic.

32. The apparatus of claim 1 wherein at least one transmissive liquid crystal spatial light modulator comprises a dust barrier.

33. The apparatus of claim 1 wherein the illumination source comprises a bubble lamp.

34. The apparatus of claim 33 wherein the illumination source images the side profile of the bubble lamp.

35. The apparatus of claim 1 wherein the illumination source comprises at least two LEDs having a different spectral range.

36. The apparatus of claim 1 further comprising at least one dithering actuator taken from the group consisting of a motor, a piezo-electric actuator, and a solenoid.

37. The apparatus of claim 36 wherein the at least one dithering actuator actuates a wire grid polarizer.

38. The apparatus of claim 1 further comprising a blur filter in the path of at least one modulated color beam.

39. The apparatus of claim 1 further comprising a blur filter in the path of at least one modulated color beam.

40. The apparatus of claim 1 further comprising a rotating plate in the path of at least one modulated color beam.

41. The apparatus of claim 40 wherein the rotating plate is tilted with respect to the optical axis.

42. The apparatus of claim 1 further comprising a shutter in the path of the telecentric polarized polychromatic light.

43. The apparatus of claim 1 wherein the at least two transmissive liquid crystal spatial light modulators are mounted as a single field-replaceable unit.

44. The apparatus of claim 2 further comprising a second condensing lens in the path of the first modulated color beam.

45. The apparatus of claim 1 further comprising a polarizer in the path of at least one modulated color beam.

46. The apparatus of claim 45 wherein the polarizer is taken from the group consisting of an absorptive polarizer and a wire-grid polarizer.

47. The apparatus of claim 1 further comprises at least one periscopic mirror assembly to package the projection lenses closer together.

48. The apparatus of claim 1 wherein at least one transmissive spatial light modulator uses magneto-photonic crystal modulation.