Optical coating on light transmissive substrates of micromirror devices

• US 7,295,363 B2
• Filed: 04/08/2005
• Issued: 11/13/2007
• Est. Priority Date: 04/08/2005
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Grasser, Regis, Patel, Satyadev, Doan, Jonathan, Heureux, Peter
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US11/102,531
• Publication Number:
  US 20060227406A1
• Time in Patent Office: 949 Days
• Field of Search: 359/223, 359/224, 359290-295, 359/298, 345/48, 345/84, 345/85, 345/108, 348/750, 348/755, 348/770, 348/771
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

Disclosed herein is method of operating a device that comprises an array of micromirrors. The method comprises a process usable for repairing stuck micromirrors of the micromirror array during the operation. The reparation process applies, at the ON state, two consecutive refresh voltages to the mirror plates of the micromirrors in the array with the pulses being separated in time longer than the characteristic oscillation time of the micromirrors. The reparation process can be applied independently to the micromirrors. Alternatively, the reparation process can be incorporated with a bias inversion process.

Claims

1. A micromirror array device, comprising:

a first and second substrates bonded together so as to form a gap therebetween;

an array of deflectable reflective mirror plates disposed within the gap;

an addressing electrode on the second substrate for deflecting the mirror plate towards the second substrate; and

a light transmissive laminate on the first substrate for rotating the mirror plate towards the first substrate, wherein said light transmissive laminate comprises an electrically conductive thin film layer and an electrically insulating thin film layer.

2. The device of claim 1, wherein the light transmissive laminate is connected to an external power source for rotating the mirror plates towards the first substrate.

3. The device of claim 1, wherein the electrically conductive thin film comprises a material that is selected from the group consisting of a nitride, and a carbide of a metal and metalloids.

4. The device of claim 2, wherein the electrically conducting layer comprises an indium-titanate-oxide.

5. The device of claim 4, wherein the electrically insulating layer comprises silicon oxide.

6. The device of claim 5, wherein the insulating layer of the transparent laminate is a first dielectric layer;

and wherein the transparent laminate further comprises a second dielectric layer that is transmissive to visible light.

7. The device of claim 6, wherein the first and second dielectric layers and the electrically conductive layer are alternatively arranged on the first substrate such that the electrically conductive layer is positioned between the first and second dielectric layers.

8. The device of claim 7, wherein the second dielectric layer comprises niobium oxide.

9. The device of claim 7, wherein the second dielectric layer comprises titanium oxide.

10. The device of claim 8, wherein the laminate further comprises a third dielectric layer.

11. The device of claim 10, wherein the third dielectric layer comprises SiO_x.

12. The device of claim 1, wherein the layers of the laminate are formed by CVD or PECVD.

13. The device of claim 10, wherein the second dielectric layer has a thickness of from 10 angstroms to 5000 angstroms.

14. The device of claim 10, wherein second dielectric layer has a thickness of from 50 angstroms to 200 angstroms.

15. The device of claim 10, wherein the second dielectric layer has a thickness around 100 angstroms.

16. The device of claim 10, wherein the second dielectric layer has an optical reflection index of from 1 to 2.7.

17. The device of claim 10, wherein the second dielectric layer has an optical reflection index of from 1.5 to 2.5.

18. The device of claim 10, wherein the second dielectric layer has an optical reflection index around 2.3.

19. The device of claim 10, wherein the first dielectric layer has a thickness of from 10 angstroms to 5000 angstroms.

20. The device of claim 10, wherein the first dielectric layer has a thickness of from 50 angstroms to 500 angstroms.

21. The device of claim 10, wherein the first dielectric layer has a thickness around 400 angstroms.

22. The device of claim 10, wherein the first dielectric layer has an optical reflection index of from 1 to 1.7 to the visible light.

23. The device of claim 10, wherein the first dielectric layer has an optical reflection index of from 1.2 to 1.5 to the visible light.

24. The device of claim 10, wherein the first dielectric layer has an optical reflection index around 1.46 to the visible light.

25. The device of claim 1, wherein the electrically conductive and transparent layer has a thickness of from 10 angstroms to 5000 angstroms.

26. The device of claim 4, wherein the indium electrically conductive and transparent layer has a thickness of from 50 angstroms to 1000 angstroms.

27. The device of claim 1, wherein the electrically conductive thin film layer of the light transmissive laminate has a thickness around 600 angstroms.

28. The device of claim 10, wherein the third dielectric layer has a thickness of from 10 angstroms to 5000 angstroms.

29. The device of claim 10, wherein said third dielectric layer has a thickness of from 50 angstroms to 1500 angstroms.

30. The device of claim 10, wherein the third dielectric layer has a thickness of around 900 angstroms.

31. The device of claim 1, wherein the first substrate is transmissive to visible light.

32. The device of claim 31, wherein the second substrate is a semiconductor substrate.

33. The device of claim 31, wherein the mirror plates are formed on the first substrate.

34. The device of claim 31, wherein the mirror plates are formed on the second substrate.

35. The device of claim 1, wherein the mirror plates are single crystal.

36. The device of claim 1, wherein each mirror plate is associated with one single addressing electrode of an array of addressing electrodes.