Spatial light modulators with light absorbing areas

• US 6,844,959 B2
• Filed: 11/26/2002
• Issued: 01/18/2005
• Est. Priority Date: 11/26/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Duboc, Robert M. Jr., Patel, Satyadev R., Huibers, Andrew G.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US10/305,509
• Publication Number:
  US 20040100680A1
• Time in Patent Office: 784 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/297, 359/298, 359/214, 359/223, 359/224, 359/846
• US Class Current: 359/297
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A projection system, a spatial light modulator, and a method for forming micromirrors are disclosed. A substrate comprises circuitry and electrodes for electrostatically deflecting micromirror elements that are disposed within an array of such elements forming the spatial light modulator. In one embodiment, the substrate is a silicon substrate having circuitry and electrodes thereon for electrostatically actuating adjacent micromirror elements, and the substrate is fully or selectively covered with a light absorbing material.

Claims

1. A spatial light modulator comprising:

a substrate having an array of electrodes and circuitry thereon; and

an array of micromirrors held above the array of electrodes and circuitry;

wherein the micromirrors comprise a hinge portion and a plate portion connected to the hinge portion, wherein the plate portion or the hinge portion comprises a light absorbing material that absorbs at least 50% of visible light incident thereon.

2. The spatial light modulator of claim 1, wherein both the hinge portion and the plate portion comprise the light absorbing material.

3. The spatial light modulator of claim 1, wherein the plate portion is a substantially flat plate comprising a visible light reflecting layer.

4. The spatial light modulator of claim 3, wherein a periphery of the flat plate is coated with the light absorbing material.

5. The spatial light modulator of claim 3, wherein an edge of the plate is covered with the light absorbing material.

6. The spatial light modulator of claim 3, wherein all edges of the plate are covered with the light absorbing material.

7. The spatial light modulator of claim 3, wherein the visible light reflecting layer is reflective on one side but substantially non-reflective on an opposite side due to a layer of the light absorbing material coating the opposite side.

8. The spatial light modulator of claim 3, wherein the plate comprises top and bottom horizontal surfaces and vertical edge surfaces.

9. The spatial light modulator of claim 8, wherein the top surface is reflective and a) the bottom surface is coated with the light absorbing material, and b) the vertical edge surfaces are coated with the light absorbing material.

10. The spatial light modulator of claim 1, wherein the light absorbing material absorbs at least 75% of light incident thereon.

11. The spatial light modulator of claim 10, wherein the light absorbing material absorbs at least 85% of the light incident thereon.

12. The spatial light modulator of claim 1, wherein the light absorbing material is black nickel or black chrome.

13. The spatial light modulator of claim 1, wherein the light absorbing material is a black or dark colored metal or metal alloy.

14. The spatial light modulator of claim 1, wherein the light absorbing material is a carbon containing polymer.

15. The spatial light modulator of claim 1, wherein the light absorbing material is deposited by sputtering.

16. The spatial light modulator of claim 1, wherein the light absorbing material is a carbon containing film.

17. The spatial light modulator of claim 1, wherein the light absorbing material comprises a carbon compound.

18. The spatial light modulator of claim 1, wherein the light absorbing material is a thin film ceramic.

19. The spatial light modulator of claim 18, wherein the thin film ceramic is deposited by chemical vapor deposition or physical vapor deposition.

20. The spatial light modulator of claim 19, wherein the thin film ceramic comprises a carbon compound.

21. The spatial light modulator of claim 20, wherein the carbon compound is CN, CAlN, TiCN, a-DLC, SiC, TiAlCN or WC.

22. The spatial light modulator of claim 18, wherein the thin film ceramic comprises a chromium compound.

23. The spatial light modulator of claim 1, wherein the light absorbing material is a black or dark colored organic or ceramic material.

24. The spatial light modulator of claim 1, wherein the plate portion is pivotably held via the hinge portion on the substrate or a second substrate by one or more posts connected to the substrate or the second substrate, wherein the one or more posts comprises a light absorbing material that absorbs at least 50% of the visible light incident thereon.

25. A projection system comprising:

a light source;

the spatial light modulator of claim 1 for reflecting a beam of light from the light source; and

projection optics for projecting light reflected off of the spatial light modulator onto a target.

26. A spatial light modulator comprising:

a substrate having an array of electrodes and circuitry thereon; and

an array of micromirrors held above the array of electrodes and circuitry;

wherein the micromirrors comprise a hinge portion and a plate portion connected to the hinge portion, wherein the plate portion or the hinge portion comprises a light absorbing material that is black or dark colored thin film ceramic or metal alloy.

27. The spatial light modulator of claim 26, wherein both the hinge portion and the plate portion comprise the light absorbing material.

28. The spatial light modulator of claim 26, wherein the plate portion is a substantially flat plate comprising a visible light reflecting layer.

29. The spatial light modulator of claim 28, wherein a periphery of the flat plate is coated with the light absorbing material.

30. The spatial light modulator of claim 28, wherein an edge of the plate is covered with the light absorbing material.

31. The spatial light modulator of claim 28, wherein all edges of the plate are covered with the light absorbing material.

32. The spatial light modulator of claim 28, wherein the visible light reflecting layer is reflective on one side but substantially non-reflective on an opposite side due to a layer of the light absorbing material coating the opposite side.

33. The spatial light modulator of claim 28, wherein the plate comprises top and bottom horizontal surfaces and vertical edge surfaces.

34. The spatial light modulator of claim 33, wherein the top horizontal surface is reflective and a) the bottom horizontal surface is coated with the light absorbing material, and b) the vertical edge surfaces are coated with the light absorbing material.

35. The spatial light modulator of claim 26, wherein the light absorbing material absorbs at least 75% of light incident thereon.

36. The spatial light modulator of claim 35, wherein the light absorbing material absorbs at least 85% of the light incident thereon.

37. The spatial light modulator of claim 26, wherein the light absorbing material is black nickel or black chrome.

38. The spatial light modulator of claim 26, wherein the light absorbing material is a carbon containing polymer.

39. The spatial light modulator of claim 26, wherein the light absorbing material is deposited by sputtering.

40. The spatial light modulator of claim 26, wherein the light absorbing material is a carbon containing film.

41. The spatial light modulator of claim 26, wherein the light absorbing material comprises a carbon compound.

42. The spatial light modulator of claim 26, wherein the thin film ceramic is deposited by chemical vapor or physical vapor deposition.

43. The spatial light modulator of claim 41, wherein the thin film ceramic comprises a carbon compound.

44. The spatial light modulator of claim 26, wherein the thin film ceramic comprises a chromium compound.

45. The spatial light modulator of claim 43, wherein the carbon compound is CN, CAlN, TiCN, a-DLC, SiC, TiAlCN or WC.

46. A projection system comprising:

a light source;

the spatial light modulator of claim 26 for reflecting a beam of light from the light source; and

projection optics for projecting light reflected off of the spatial light modulator onto a target.