Micromirror having offset addressing electrode

• US 20050286112A1
• Filed: 09/21/2004
• Published: 12/29/2005
• Est. Priority Date: 06/23/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Patel, Satyadev
• Granted Patent: US 7,113,322 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

The micromirror device of the present invention comprises a reflective deflectable mirror plate and an addressing electrode provided for deflecting the mirror plate, wherein the addressing electrode is displaced along a direction perpendicular to the length of the hinge such that a portion of the addressing electrode is extended beyond the mirror plate.

Claims

1. a micromirror device, comprising:

a mirror plate operable to rotate above a substrate and at most one addressing electrode for rotating the mirror plate, wherein the mirror plate and the addressing electrode are positioned such that an imaginary line connecting a geometric center of the mirror plate and a geometric center of the addressing electrode is from 5°

to 50°

degrees relative to a line normal to the addressing electrode;

2. The method of claim 1, wherein the electrode is at a position that is shifted along a direction parallel to an edge of the mirror plate when viewed from the top of the mirror plate.

3. The device of claim 1, wherein the imaginary line connecting the geometric centers of the mirror plate and the addressing electrode has an angle with the normal of the addressing electrode, wherein the angle is from 10°

to 40°

degrees.

4. The device of claim 3, wherein the angle is from 15°

to 30°

degrees.

5. The device of claim 3, wherein the angle is from 15°

to 25°

degrees.

6. The device of claim 3, wherein a ratio of a vertical distance between the mirror plate and the addressing electrode to a length of the mirror plate is from 1:

1 to 1;

6.

7. The device of claim 1, wherein the mirror plate is attached to a hinge such that the mirror plate is operable to rotate asymmetrically.

8. The device of claim 7, wherein an attachment point of the mirror plate to the hinge is neither at a geometric center of the mirror plate nor on at least one of a plurality of diagonals of the mirror plate.

9. The device of claim 7, wherein the hinge is parallel to but offset from a diagonal of the mirror plate.

10. The device of claim 7, wherein the hinge is offset from but not parallel to a diagonal of the mirror plate.

11. The device of claim 7, wherein the hinge and the mirror plate are in different planes parallel to the substrate.

12. The device of claim 7, wherein the addressing electrode is displaced relative to the mirror plate such that the addressing electrode is extended beyond the mirror plate.

13. The device of claim 12, wherein the addressing electrode is extended beyond a furthest point of the mirror plate from the hinge along a direction perpendicular to the hinge.

14. The device of claim 13, wherein a displacement distance between a furthest point of the addressing electrode to the furthest point of the mirror plate is 1 micron or more, where in the furthest point of the mirror plate is a point having the largest distance from the hinge, and wherein the furthest point of the addressing electrode having the largest distance from the hinge.

15. The device of claim 14, wherein the displacement distance is 2 microns or more.

16. The device of claim 14, wherein the displacement distance is 3 microns or more.

17. The device of claim 7, wherein a ratio of the displacement distance to a gap between the mirror plate and the hinge is 0.5 or more, wherein the displacement distance is a distance between a furthest point of the addressing electrode to the furthest point of the mirror plate, where in the furthest point of the mirror plate is a point having the largest distance from the hinge, and wherein the furthest point of the addressing electrode having the largest distance from the hinge.

18. The device of claim 17, wherein the ratio is 1.1 or more.

19. The device of claim 17, wherein the ratio is 1.2 or more.

20. The device of claim 17, wherein the ratio is from 1:

2 to 1;

4

21. The device of claim 17, wherein the ratio is around 1:

3.

22. The device of claim 1, wherein the hinge and the mirror plate are in a same plane parallel to the substrate.

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

24. The device of claim 9, wherein the mirror plate is operable to rotate to an ON state angle of 12°

degrees or higher.

25. The device of claim 24, wherein the mirror plate is operable to rotate to an OFF state angle of −

2°

to −

6°

degrees.

26. A spatial light modulator, comprising:

an array of pixels, each pixel comprising a micromirror, wherein each micromirror comprises a mirror plate operable to rotate on a substrate, and an addressing electrode for rotating the mirror plate, wherein the mirror plate and the addressing electrode are positioned such that an imaginary line connecting a geometric center of the mirror plate and a geometric center of the addressing electrode is 5°

to 50°

degrees relative to the normal of the addressing electrode.

27. A micromirror device, comprising:

a mirror plate operable to rotate on a substrate and an addressing electrode, wherein the addressing electrode is visible when viewed from directly above the mirror plate with the addressing electrode positioned underneath and offset from the mirror plate.

28. The device of claim 27, wherein the mirror plate is attached to a hinge such that the mirror plate is operable to rotate asymmetrically.

29. The device of claim 28, wherein an attachment point of the mirror plate to the hinge is neither at a geometric center of the mirror plate nor at a diagonal of the mirror plate.

30. The device of claim 29, wherein the hinge is parallel to but offset from a diagonal of the mirror plate.

31. The device of claim 29, wherein the hinge is offset from but not parallel to a diagonal of the mirror plate.

32. The device of claim 28, wherein the hinge and the mirror plate are in different planes parallel to the substrate.

33. The device of claim 32, wherein an imaginary line connecting a geometric center of the addressing electrode and a geometric center of the mirror plate is not normal to the addressing electrode.

34. The device of claim 33, wherein the addressing electrode is displaced relative to the mirror plate such that the addressing electrode is extended beyond the mirror plate.

35. The device of claim 34, wherein the addressing electrode is extended beyond a furthest point of the mirror plate from the hinge along a direction perpendicular to the hinge.

36. The device of claim 34, wherein a displacement distance between a furthest point of the addressing electrode to the furthest point of the mirror plate is 1 micron or more, where in the furthest point of the mirror plate is a point having the largest distance from the hinge, and wherein the furthest point of the addressing electrode having the largest distance from the hinge.

37. The device of claim 36, wherein the displacement distance is 2 microns or more.

38. The device of claim 37, wherein the displacement distance is 3 microns or more.

39. The device of claim 36, wherein a ratio of the displacement distance to a gap between the mirror plate and the hinge is 0.5 or more, wherein the displacement distance is a distance between a furthest point of the addressing electrode to the furthest point of the mirror plate, where in the furthest point of the mirror plate is a point having the largest distance from the hinge, and wherein the furthest point of the addressing electrode having the largest distance from the hinge.

40. The device of claim 39, wherein the ratio is 1.1 or more.

41. The device of claim 40, wherein the ratio is 1.2 or more.

42. The device of claim 27, wherein the mirror plate is not deflected.

43. The device of claim 27, wherein said addressing electrode is a single addressing electrode associated with said mirror plate for rotating said mirror plate.

44. A spatial light modulator, comprising:

an array of pixels, each pixel comprising a micromirror that comprises a mirror plate operable to rotate on a substrate, and an addressing electrode for rotating the mirror plate, wherein the addressing electrode is visible when viewed from directly above the mirror plate with the addressing electrode positioned underneath and offset the mirror plate.

45. A projection system, comprising;

an illumination system;

a spatial light modulator having an array of pixels, each pixel having a micromirror that comprises a mirror plate operable to rotate on a substrate, and an addressing electrode for rotating the mirror plate, wherein the addressing electrode is visible when viewed from directly above the mirror plate with the addressing electrode positioned underneath and offset the mirror plate;

an optical element; and

a display target.

46. The system of claim 45, wherein the illumination system comprises:

a light source;

a light pipe; and

a color wheel.

47. The system of claim 46, wherein the color wheel is positioned after the light source and the light pipe along a propagation path of the light.

48. The system of claim 46, wherein the color wheel is positioned between the light source and the light pipe along a propagation path of the light.

49. A projection system, comprising:

an illumination system;

a spatial light modulator having an array of pixels, each pixel having a micromirror that comprises;

a mirror plate operable to rotate on a substrate, and an addressing electrode for rotating the mirror plate, wherein the mirror plate and the addressing electrode are positioned such that an imaginary line connecting a geometric center of the mirror plate and a geometric center of the addressing electrode is 5°

to 50°

degrees relative to the normal of the addressing electrode;

an optical element; and

a display target.

50. The system of claim 49, wherein the illumination system comprises:

a light source;

a light pipe; and

a color wheel.

51. The system of claim 50, wherein the color wheel is positioned after the light source and the light pipe along a propagation path of the light.

52. The system of claim 50, wherein the color wheel is positioned between the light source and the light pipe along a propagation path of the light.

53. A spatial light modulator:

comprising;

an array of pixels, each pixel having a micromirror that has a mirror plate operable to rotate on a substrate, and an addressing electrode for rotating the mirror plate, wherein the addressing electrode is positioned directly underneath at least two mirror plates.

54. The device of claim 53, wherein the addressing electrode is positioned directly underneath at least three mirror plates.

55. The device of claim 53, wherein a ratio of a total number of mirror plates to a total number of addressing electrodes is substantially 1.

56. A spatial light modulator, comprising:

an array of micromirrors, each comprising a deflectable and reflective mirror plate attached to a deformable hinge that is held on a substrate; and

an array of addressing electrodes, each of which is positioned proximate to a mirror plate of the array of micromirrors for addressing and deflecting the mirror plate, wherein the addressing electrode extends beyond the furthest point of the mirror plate at a non-deflected state.

57. The spatial light modulator of claim 56, wherein the addressing electrode extends into a gap between mirror plates of adjacent micromirrors of the micromirror array.

58. The spatial light modulator of claim 57, wherein the addressing electrode of the micromirror extends into an adjacent micromirror.

59. The spatial light modulator of claim 57, wherein the substrate is transmissive to visible light.

60. The spatial light modulator of claim 59, wherein each micromirror in the array has one addressing electrode associated therewith.

61. The spatial light modulator of claim 60, wherein the mirror plate and hinge are on different planes parallel to the substrate.

62. The spatial light modulator of claim 60, wherein the mirror plate is in the same plane of the hinge when the mirror plate is not deflected.

63. The spatial light modulator of claim 61, wherein the mirror plate is attached to the hinge at an attachment point that is not at the center the mirror plate such that the mirror plate is operable to rotate to a larger angle in one direction than that of the opposite direction.