Light blocking layers in MEMS packages

• US 7,042,623 B1
• Filed: 10/19/2004
• Issued: 05/09/2006
• Est. Priority Date: 10/19/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Tarn, Terry, Huibers, Andrew, Patel, Satyadev
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): Tra, Tuyen
• Application Number:
  US10/969,258
• Publication Number:
  US 20060082859A1
• Time in Patent Office: 567 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298, 359/223, 359/224, 359/322, 359/323
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

Disclosed herein is a micromirror array device package having a light absorbing material disposed within the package for reducing undesired light scattering. The light absorbing material can be deposited as a thin film (or strip, frame, segments or a combination thereof), or as a vertical wall insert between the micromirror array device and a cover substrate of the package.

Claims

1. A micromirror array device package, comprising:

a micromirror array device;

a package substrate having a plurality of interior surfaces together defining a cavity in which the micromirror array device is disposed;

a cover substrate disposed such that the micromirror array device is capable of being enclosed between the package substrate and cover substrate; and

a light blocking material deposited on at least one of the plurality of interior surfaces of the package substrate for reducing scattered light therefrom, wherein the light absorbing material is more absorbing to visible light than said at least one interior surface.

2. The package of claim 1, further comprising a light absorbing wall that is not a portion of the packaging substrate.

3. The package of claim 2, wherein the light absorbing wall is disposed between a top surface of the micromirror array device and a bottom surface of the cover substrate.

4. The package of claim 1, wherein light absorbing material is deposited as a continuous film.

5. The package of claim 1, wherein light absorbing material is deposited as a strip.

6. The package of claim 1, wherein light absorbing material is deposited as a frame.

7. The package of claim 1, wherein light absorbing material is deposited as a segment of a film or a strip or a frame.

8. The package of claim 1, wherein light absorbing material is deposited on a surface of the cover substrate.

9. The package of claim 1, wherein the absorbing material is deposited on an interior side wall of the package substrate.

10. The package of claim 1, wherein the light absorbing material is deposited on a supporting surface of the cavity in the packaging substrate.

11. The package of claim 1, wherein the light absorbing material is deposited on an edge of the micromirror array device.

12. The package of claim 11, wherein the micromirror array device comprises two substrates having an array of reflective and deflectable micromirrors and an array of addressing electrodes.

13. The package of claim 12, wherein one of the two substrates has the micromirrors formed thereon, while the other substrate has the electrodes formed thereon;

and wherein the edges of the substrate having the micromirrors are deposited with the light absorbing material.

14. The package of claim 13, wherein the edges of the substrate having the addressing electrodes are deposited with the light absorbing material.

15. The package of claim 1, wherein the micromirror array device comprises an array of micromirrors and an array of electrodes formed on a substrate.

16. The package of claim 1, wherein the light absorbing material comprises a Chromium.

17. The package of claim 1, wherein the light absorbing material comprises a Chromium oxide.

18. The package of claim 1, wherein the light absorbing material comprises an element that is selected from the group comprising:

nickel, CrN, TiAlN, TaN, CN, CAlN, and TiCN.

19. The package of claim 1, wherein the light absorbing material comprises an element that is selected from the group comprising:

vitreous carbon, SiC, TiAlCN, and WC.

20. The package of claim 1, wherein the light absorbing material is a multilayered structure.

21. The package of claim 20, wherein the light absorbing material comprises:

TiWC, WC/C or TiAlN/WC/C.

22. The package of claim 1, wherein the cover substrate is transmissive to visible light.

23. The package of claim 22, wherein the cover substrate has an anti-reflection film formed thereon.

24. The package of claim 1, wherein the light absorbing material is deposited as a thin-film having a thickness in an order of microns.

25. The package of claim 24, wherein the thickness of the light absorbing material is 50 microns or less.

26. The package of claim 1, wherein the light absorbing material is deposited by CVD, PVD, electroplating, or chemical mechanical polarization.

27. The package of claim 1, wherein the cover substrate is directly bonded to the packaging substrate.

28. The package of claim 1, wherein the micromirror array device comprises an array of deflectable and reflective micromirrors, and an array of addressing electrodes.

29. The package of claim 1, wherein the light absorbing material absorbs 85% or more of the visible light incident thereto.

30. The package of claim 1, wherein the light absorbing material absorbs 95% or more of the visible light incident thereto.

31. The package of claim 1, wherein the light absorbing material is black in color.

32. The package of claim 1, wherein the light absorbing material is dark gray or dark blue.

33. The package of claim 1, wherein the package substrate comprises a flat plate and an annular ring bonded to the circumference of the flat plate.

34. The package of claim 1, wherein the micromirror array device comprises a glass substrate and a silicon substrate bonded to the glass substrate, wherein the silicon substrate is attached to a supporting surface of the packaging substrate.

35. The package of claim 34, wherein the silicon substrate comprises a plurality of wires that are bonded to the packaging substrate.

36. The package of claim 1, wherein the light absorbing material is deposited on the top surface of the cavity in the packaging substrate, wherein said top surface is substantially parallel to the cover substrate.

37. A display system, comprising:

a light source;

a spatial light modulator of claim 1;

a plurality of optical elements; and

a viewing screen.

38. A micromirror army device package, comprising:

a micromirror array device that is fully encapsulated within a space between a cover substrate and a packaging substrate bonded to the cover substrate, wherein the micromirror array device is attached to one of the two substrates but not the both; and

a light absorbing material disposed on an interior surface of the packaging substrate for absorbing light scattered within the space, wherein the light absorbing material is more absorbing than the packaging substrate.

39. The package of claim 38, wherein the package substrate comprises a flat plate and an annular ring bonded to the circumference of the flat plate.

40. The package of claim 38, further comprising:

a vertical wall insert spaced apart from the interior surfaces for absorbing scattered light.

41. A micromirror array device package, comprising:

a micromirror array device;

a packaging substrate having a plurality of interior surfaces together defining a cavity in which the micromirror device is disposed;

a cover substrate bonded to the packaging substrate such that the micromirror array device is encapsulated within the cavity; and

a vertical wall within the cavity for absorbing scattered light, wherein the vertical wall is more absorbing than the packaging substrate.

42. The package of claim 41, wherein the vertical wall is an insert that is spaced apart from the interior surfaces.

43. The package of claim 41, wherein the vertical wall is deposited on one of the plurality of interior surfaces.

44. The package of claim 41, wherein the vertical wall is deposited on a side wall of the micromirror array device.

45. The package of claim 44, wherein the vertical wall is deposited on a silicon or glass substrate of the micromirror array device.

46. The package of claim 41, wherein the vertical wall is operable to absorb 85% or more of the visible light incident thereto.

47. The package of claim 41, wherein the vertical wall is operable to absorb 95% or more of the visible light incident thereto.

48. The package of claim 41, wherein the vertical wall is black in color.

49. The package of claim 41, wherein the vertical wall is dark gray or dark blue in color.

50. The package of claim 41, wherein the vertical wall comprises chromium.

51. The package of claim 41, wherein the vertical wall comprises chromium oxide.

52. A display system, comprising:

a light source;

a spatial light modulator of claim 41;

a plurality of optical elements; and

a viewing screen.