Granted Patent B2

US 8,172,403 · App. 12/469,727 · Granted May 8, 2012

Abstract

Claims (31)

1. A coherent light projection system comprising:

a coherent light source system configured at least to emit coherent light;

an image forming system including one or more spatial light modulators configured to interact with the coherent light in a manner consistent with image data;

a relay system configured at least to form an intermediate image at an intermediate image plane from coherent light output from the image forming system, the intermediate image being an aerial real image;

a speckle reduction element located at or substantially at the intermediate image plane, the speckle reduction element having surface structures formed on a curved surface configured to transfer the intermediate image through it;

a movement generating system configured at least to move the speckle reduction element; and

a projection subsystem configured at least to project the intermediate image, as transferred through the speckle reduction element, onto a display surface, wherein the projection subsystem is adapted to project a curved object surface onto the display surface, and wherein the curvature of the curved object surface substantially matches the curvature of the curved surface of the speckle reduction element and is adapted to have a curvature that substantially matches a typical amount of curvature associated with film buckle effects for film-based projection systems.

2. The system of claim 1 , wherein the projection subsystem is designed to project a curved object surface having 100-200 μm sag over a one inch wide area.

3. The system of claim 1 , wherein the curved surface of the speckle reduction element falls within a depth of focus of the relay lens.

4. The system of claim 1 , wherein the surface structures are etched into the curved surface of the speckle reduction element.

5. The system of claim 4 , wherein the curved surface comprises randomly or substantially randomly distributed surface structures.

6. The system of claim 1 , wherein the image forming system comprises light modulators and a dichroic combiner that aligns a plurality of color channels from the coherent light source system onto a common axis.

7. The system of claim 1 , wherein the movement-generating system is configured at least to cause motion of the speckle reduction element in a direction parallel to an optical axis of the speckle reduction element.

8. The system of claim 7 , wherein the motion parallel to the optical axis is within a depth of focus of the projection subsystem.

9. The system of claim 7 , wherein the motion parallel to the optical axis is within a depth of focus of the relay system.

10. The system of claim 7 , wherein the movement generating system is further configured at least to cause motion of the speckle reduction element in a direction perpendicular to the optical axis of the speckle reduction element.

11. The system of claim 1 , wherein the speckle reduction element comprises a lenslet arrangement formed on a surface of the speckle reduction element, the lenslet arrangement comprising lenslets each having an aperture, wherein each of all or substantially all of the lenslet apertures is greater than or equal to a size of a pixel of the intermediate image at the intermediate image plane.

12. The system of claim 11 , wherein the lenslet arrangement comprises a random or substantially random distribution of lenslets.

13. The system of claim 11 , wherein the lenslet arrangement comprises lenslets in or substantially in a hexagonal, linear, or diagonal pattern.

14. The system of claim 11 , wherein the lenslet arrangement entirely or almost entirely comprises abutting lenslets.

15. The system of claim 11 , wherein the lenslet arrangement entirely or almost entirely comprises non-abutting or sparsely distributed lenslets.

16. The system of claim 11 , wherein the movement-generating system is configured at least to move the speckle reduction element in-plane a distance that is greater than or equal to a period of lenslet repetition.

17. The system of claim 11 , wherein the lenslet arrangement is configured at least to pass a fourth order energy or lower of the intermediate image, as transferred through the speckle reduction element, into an acceptance aperture of the projection subsystem.

18. The system of claim 1 , wherein the image forming system is further configured to project an initial image having a first size, and wherein the intermediate image has a second size greater than or equal to the first size.

19. A method of projecting light comprising:

generating coherent light from a coherent light source system;

forming an image with an image forming system including one or more spatial light modulators that interact with the coherent light in a manner consistent with image data;

forming an intermediate image at an intermediate image plane at least from coherent light output from the image forming system, the intermediate image being an aerial real image formed with a relay system;

transferring the intermediate image through a curved surface of a speckle reduction element located at or substantially at the intermediate image plane, the speckle reduction element ( 40 ) having surface structures formed on the curved surface;

moving the speckle reduction element with a movement generating system while the intermediate image is transferred through the speckle reduction element; and

projecting the intermediate image, as transferred through the speckle reduction element onto a display surface using a projection subsystem, wherein the projection subsystem is adapted to project a curved object surface onto the display surface, and wherein the curvature of the curved object surface substantially matches the curvature of the curved surface of the speckle reduction element and is adapted to have a curvature that substantially matches a typical amount of curvature associated with film buckle effects for film-based projection systems.

Assignments (18)