Methods and apparatus for spatial light modulation

• US 7,729,037 B2
• Filed: 03/17/2008
• Issued: 06/01/2010
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Steyn, Jasper Lodewyk, Hagood, Nesbitt W. IV
• Primary Examiner(s): Choi; William C
• Application Number:
  US12/049,852
• Publication Number:
  US 20080158636A1
• Time in Patent Office: 806 Days
• Field of Search: 359/198, 359/230, 359/233, 359/290, 359/291, 359/198.1
• US Class Current: 359/290
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays

Abstract

Improved apparatus and methods for spatial light modulation are disclosed which utilize optical cavities having both front and rear reflective surfaces. Light-transmissive regions are formed in the front reflective surface for spatially modulating light.

Claims

1. A display apparatus for forming an image comprising:

a layer of reflective material for reflecting light away from a front of the display apparatus;

an array of MEMS-based light modulators supported proximate the layer of reflective material, wherein each of the MEMS-based light modulators includes a modulation element and an actuator for moving the modulation element relative to the layer of reflective material thereby forming pixels on the display apparatus; and

a plurality of apertures formed in the layer of reflective material for allowing light to pass through the layer of reflective material.

2. The display apparatus of claim 1, wherein the modulation element comprises a shutter for selectively obstructing at least one of the plurality of apertures.

3. The display apparatus of claim 1, wherein the each aperture of the plurality of apertures corresponds to one of the MEMS-based light modulators.

4. The display apparatus of claim 1, comprising a spacer disposed between the layer of reflective material and the array to keep the modulation elements about a predetermined distance from the layer of reflective material.

5. The display apparatus of claim 1, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 100 microns away from the layer of reflective material.

6. The display apparatus of claim 1, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 10 microns away from the layer of reflective material.

7. The display apparatus of claim 1, wherein the layer of reflective material reflects light impinging on a surface of the layer of reflective material facing away from the array of MEMS-based light modulators.

8. The display apparatus of claim 7, wherein the layer of reflective material absorbs light impinging on a surface of the layer of reflective material facing towards the array of MEMS-based light modulators.

9. The display apparatus of claim 7, comprising a second layer of reflective material positioned on an opposite side of the layer of reflective material from the MEMS-based light modulators, and facing towards the layer of reflective materials.

10. The display apparatus of claim 9, comprising a light guide positioned between the layer of reflective material and the second layer of reflective material.

11. The display apparatus of claim 1, comprising a liquid located at least between the modulation elements and the layer of reflective material.

12. The display apparatus of claim 11, wherein the liquid is a lubricant.

13. The display apparatus of claim 1, wherein the layer of reflective material comprises a dielectric mirror.

14. The display apparatus of claim 1, wherein the layer of reflective material comprises a metal.

15. The display apparatus of claim 1, wherein the MEMS-based light modulators are configured for moving the modulation elements substantially in a plane parallel to the layer of reflective material.

16. A display apparatus for forming an image comprising:

a layer of reflective material for reflecting light away from a front of the display apparatus;

an array of MEMS-based light modulators supported proximate the layer of reflective material, wherein each of the MEMS-based light modulators includes a modulation element and an actuator for moving the modulation element relative to the layer of reflective material thereby forming pixels on the display apparatus, wherein the layer of reflective material reflects light impinging on a surface of the layer of reflective material facing away from the array of MEMS-based light modulators; and

a second layer of reflective material positioned on an opposite side of the layer of reflective material from the MEMS-based light modulators, and facing towards the layer of reflective materials.

17. The display apparatus of claim 16, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 100 microns away from the layer of reflective material.

18. The display apparatus of claim 16, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 10 microns away from the layer of reflective material.

19. The display apparatus of claim 16, wherein the layer of reflective material absorbs light impinging on a surface of the layer of reflective material facing towards the array of MEMS-based light modulators.

20. The display apparatus of claim 16, comprising a liquid located at least between the modulation elements and the layer of reflective material.

21. A display apparatus for forming an image comprising:

a layer of reflective material for reflecting light away from a front of the display apparatus; and

an array of MEMS-based light modulators supported proximate the layer of reflective material, wherein each of the MEMS-based light modulators includes a modulation element and an actuator for moving the modulation element relative to the layer of reflective material thereby forming pixels on the display apparatus, wherein the layer of reflective material reflects light impinging on a surface of the layer of reflective material facing away from the array of MEMS-based light modulators and the layer of reflective material absorbs light impinging on a surface of the layer of reflective material facing towards the array of MEMS-based light modulators.

22. The display apparatus of claim 21, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 100 microns away from the layer of reflective material.

23. The display apparatus of claim 21, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 10 microns away from the layer of reflective material.

24. The display apparatus of claim 21, comprising a second layer of reflective material positioned on an opposite side of the layer of reflective material from the MEMS-based light modulators, and facing towards the layer of reflective materials.

25. The display apparatus of claim 21, comprising a liquid located at least between the modulation elements and the layer of reflective material.

26. A display apparatus for forming an image comprising:

a layer of reflective material for reflecting light away from a front of the display apparatus;

an array of MEMS-based light modulators supported proximate the layer of reflective material, wherein each of the MEMS-based light modulators includes a modulation element and an actuator for moving the modulation element relative to the layer of reflective material thereby forming pixels on the display apparatus; and

a liquid located at least between the modulation elements and the layer of reflective material.

27. The display apparatus of claim 26, wherein the liquid is a lubricant.

28. The display apparatus of claim 26, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 100 microns away from the layer of reflective material.

29. The display apparatus of claim 26, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 10 microns away from the layer of reflective material.

30. The display apparatus of claim 26, comprising a second layer of reflective material positioned on an opposite side of the layer of reflective material from the MEMS-based light modulators, and facing towards the layer of reflective materials.

31. The display apparatus of claim 28, wherein the layer of reflective material absorbs light impinging on a surface of the layer of reflective material facing towards the array of MEMS-based light modulators.

32. A display apparatus for forming an image comprising:

a layer of reflective material for reflecting light away from a front of the display apparatus, wherein the layer of reflective material comprises a dielectric mirror; and

an array of MEMS-based light modulators supported proximate the layer of reflective material, wherein each of the MEMS-based light modulators includes a modulation element and an actuator for moving the modulation element substantially to the layer of reflective material thereby forming pixels on the display apparatus.

33. The display apparatus of claim 32, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 100 microns away from the layer of reflective material.

34. The display apparatus of claim 32, wherein the modulation elements of the MEMS-based light modulators are maintained less than about 10 microns away from the layer of reflective material.

35. The display apparatus of claim 34, comprising a second layer of reflective material positioned on an opposite side of the layer of reflective material from the MEMS-based light modulators, and facing towards the layer of reflective materials.

36. The display apparatus of claim 35, wherein the layer of reflective material absorbs light impinging on a surface of the layer of reflective material facing towards the array of MEMS-based light modulators.

37. The display apparatus of claim 35, comprising a liquid located at least between the modulation elements and the layer of reflective material.