STEREOSCOPIC PROJECTOR WITH ROTATING SEGMENTED DISK

• US 20110013144A1
• Filed: 07/14/2009
• Published: 01/20/2011
• Est. Priority Date: 07/14/2009
• Status: Active Grant

• Current Assignee: IMAX Theatres International Limited (IMAX Corporation)
• Original Assignee: Eastman Kodak Company
• Inventors: Metzger, Robert J., Kircher, James R., Bietry, Joseph R., Silverstein, Barry D.
• Granted Patent: US 8,066,382 B2
• Time in Patent Office: Days
• US Class Current: 353/8
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: G03B 35/26 using polarised or coloured light separating different viewpoint images
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/346 using prisms or semi-transparent mirrors
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 9/3164 using multiple light sources
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A stereoscopic digital image projecting system has a light source system providing polarized illumination having a first polarization state and a beam splitting system with a rotating segmented disk in the illumination, alternately generating first and second light beams, the rotating segmented disk having outer segments alternately transmissive and non-transmissive and inner segments radially aligned with the outer segments and alternately reflective and transmissive. A polarization rotator in a path of either the first or second light beam rotates the first polarization state to a second state orthogonal to the first. A combining system combines the first and second light beams into a combined light beam. A spatial light modulator modulates the combined light beam in a manner consistent with stereoscopic image data to form first and second modulated images having substantially orthogonal polarization states. Projection optics project the modulated images onto a display surface.

Claims

1. A stereoscopic digital image projecting system comprising:

a light source system energizable to provide polarized illumination having a first polarization state;

a beam splitting system comprising a rotating segmented disk disposed in a path of the polarized illumination and alternately generating first and second light beams from the polarized illumination, the rotating segmented disk comprising outer segments alternately transmissive and non-transmissive and inner segments radially aligned with the outer segments and each alternately reflective and transmissive, wherein the inner reflective segments correspond with the outer transmissive segments;

a polarization rotator positioned in a path of either the first or second light beam and rotating the first polarization state to a second polarization state orthogonal or substantially orthogonal to the first polarization state;

a combining system combining the first and second light beams into a combined light beam;

a spatial light modulator modulating the combined light beam in a manner consistent with stereoscopic image data to form a first modulated image from illumination in the combined light beam having the first polarization state and to form a second modulated image from illumination in the combined light beam having the second polarization state; and

projection optics configured to project the first and second modulated images onto a display surface.

2. The system of claim 1, wherein the first light beam is generated when the polarized illumination is transmitted through a transmissive inner segment and the second light beam is generated when the polarized illumination is reflected from a reflective inner segment and transmitted through a transmissive outer segment.

3. The system of claim 2, further including a converging optical element that converges the polarized illumination to a reduced light beam diameter at the beam splitting system.

4. The system of claim 3, wherein the converging optical element is a lens or a mirror.

5. The system of claim 3, wherein the converging optical element converges the polarized illumination such that a minimum beam diameter for the second light beam occurs at a point following its reflection from the reflective inner segment and prior to its transmission through the transmissive outer segment.

6. The system of claim 5, wherein a first beam diameter of the first light beam when it passes through the transmissive inner segment is equal or substantially equal to a second beam diameter of the second light beam when it passes through the transmissive outer segment.

7. The system of claim 2, wherein the beam splitting system further comprises a mirror that directs light reflected from the inner reflective segments through the outer transmissive segments.

8. The system of claim 7, wherein the mirror is angled appropriately to converge the first light beam and the second light beam thereby functioning as a component of the combining system.

9. The system of claim 8, wherein the first light beam and the second light beam are converged at the modulator.

10. The system of claim 8, wherein the first light beam and the second light beam are converged onto an integrating bar or a lenslet array.

11. The system of claim 7, wherein the mirror is a reflective retarder that performs the function of the polarization rotator.

12. The system of claim 1, wherein the outer non-transmissive segments are light absorbing.

13. The system of claim 1, wherein the outer non-transmissive segments are reflective.

14. The system of claim 13, wherein a back surface of the outer reflective segments is light absorbing, scattering, or both absorbing and scattering.

15. The system of claim 1, wherein the rotating segmented disk comprises only two outer segments and two inner segments.

16. The system of claim 1, wherein at least a portion of the rotating segmented disk is textured in a manner that reduces coherence artifacts.

17. The system of claim 1, wherein the combining system comprises a polarizing beam splitter, an integrating bar, or a lenslet array.

18. The system of claim 1, wherein the polarization rotator comprises a half-wave plate or a reflective retarder or an electronic retarder.

19. The system of claim 1, wherein the combining system comprises a polarization beam combiner.

20. The system of claim 19, wherein the polarization beam combiner is a thin film plate, thin film cube, wire grid, or Brewster angle element.