Packaged micromirror array for a projection display

• US 7,006,275 B2
• Filed: 05/28/2004
• Issued: 02/28/2006
• Est. Priority Date: 08/30/2000
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Huibers, Andrew G.
• Primary Examiner(s): Mack, Ricky L.
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US10/857,055
• Publication Number:
  US 20040218154A1
• Time in Patent Office: 641 Days
• Field of Search: 359/198, 359/224, 359/225, 359/290, 359/292, 359/295, 359/298, 359/316, 348/771, 345/31, 345/108
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

In order to minimize light diffraction along the direction of switching and more particularly light diffraction into the acceptance cone of the collection optics, in the present invention, micromirrors are provided which are not rectangular. Also, in order to minimize the cost of the illumination optics and the size of the display unit of the present invention, the light source is placed orthogonal to the rows (or columns) of the array, and/or the light source is placed orthogonal to a side of the frame defining the active area of the array. The incident light beam, though orthogonal to the sides of the active area, is not however, orthogonal to any substantial portion of sides of the individual micromirrors in the array. Orthogonal sides cause incident light to diffract along the direction of micromirror switching, and result in light ‘leakage’ into the ‘on’ state even if the micromirror is in the ‘off’ state. This light diffraction decreases the contrast ratio of the micromirror. The micromirrors of the present invention result in an improved contrast ratio, and the arrangement of the light source to micromirror array in the present invention results in a more compact system. Another feature of the invention is the ability of the micromirrors to pivot in opposite direction to on and off positions (the on position directing light to collection optics), where the movement to the on position is greater than movement to the off position. A further feature of the invention is a package for the micromirror array, the package having a window that is not parallel to the substrate upon which the micromirrors are formed. One example of the invention includes all the above features.

Claims

1. A packaged micromirror array for a projection display, comprising:

a package having an array of micromirrors therein, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state by pulse width modulation to achieve a gray scale image on a target; and

wherein each micromirror corresponds to a pixel in a viewed image on the target;

the package having a light transmissive window, wherein the array of micromirrors is disposed in the package having the light transmissive window;

the package further comprising a substantially rectangular mask disposed on or above the micromirror array; and

wherein each of the four micromirror sides of the micromirrors is not parallel to any sides of the rectangular mask.

2. The packaged micromirror array of claim 1, further comprising bond wires at one end of the package electrically connecting the micromirror array to the package for actuation of the micromirrors.

3. The packaged micromirror array of claim 2, wherein the micromirrors are positioned on a lattice aligned at an angle to the sides of the rectangular mask.

4. The packaged micromirror array of claim 2, wherein the package is a hermetic package.

5. The packaged micromirror array of claim 2, wherein the micromirror array has an area of from 1 cm² to 1 in².

6. The packaged micromirror array of claim 1, wherein the mask is provided as part of the package.

7. The packaged micromirror array of claim 6, wherein the micromirror has a resolution of 1,920,000 or higher.

8. The packaged micromirror array of claim 1, wherein the mask is formed on the package window and extends around a periphery of the micromirror array.

9. The packaged micromirror array of claim 1, wherein a molecular scavenger is provided within the package.

10. The packaged micromirror array of claim 1, wherein a getter is provided within the package.

11. The packaged micromirror array of claim 1, wherein a source of stiction reducing agent is provided within the package.

12. The packaged micromirror array of claim 1, wherein the micromirrors are capable of rotating at least +12 degrees to the ON position.

13. The packaged micromirror array of claim 1, in HDTV format.

14. The packaged micromirror array of claim 1, wherein the micromirrors are positioned on a lattice aligned at an angle to the X and Y axes of the array.

15. The packaged micromirror array of claim 1, wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, and wherein the substrate, micromirror plates and hinges are disposed in different planes.

16. The packaged micromirror array of claim 15, wherein a first gap is defined between the hinge and the micromirror plate, and a second gap is defined between the micromirror plate and the substrate.

17. The packaged micromirror array of claim 16, wherein a molecular scavenger is provided within the package.

18. The packaged micromirror array of claim 15, wherein a first gap is defined between the substrate and the hinge and a second gap is defined between the hinge and the micromirror plate.

19. The packaged micromirror array of claim 1, wherein the micromirrors comprise metal and a dielectric material, wherein the dielectric material is a nitride, carbide or oxide of silicon.

20. The packaged micromirror array of claim 1, wherein the package is a partially hermetic package.

21. The packaged micromirror array of claim 1, wherein the micromirror array comprises circuitry and electrodes on a semiconductor substrate, and bond wires for electrically connecting the substrate to the package.

22. The packaged micromirror array of claim 1, wherein hinges of the micromirror extend parallel to leading and trailing sides of the rectangular mask.

23. The packaged micromirror array of claim 1, wherein at least 1000 micromirror are in the micromirror array.

24. The packaged micromirror array of claim 1, wherein the micromirrors are tiled together.

25. The packaged micromirror array of claim 1, wherein millions of micromirrors are provided.

26. The packaged micromirror array of claim 1, wherein each micromirror has a switching axis substantially parallel to at least one side of the mask.

27. The packaged micromirror array of claim 1, wherein the micromirror array is a rectangular array and wherein each micromirror has a switching axis substantially parallel to at least one side of the array.

28. The packaged micromirror array of claim 27, wherein each micromirror has a switching axis that is at an angle of from 35 to 60 degrees to sides of the micromirror.

29. The packaged micromirror array of claim 28, wherein each micromirror comprises a hinge and micromirror plate that are disposed in different planes, and wherein the hinge has a width of from 0.1 to 10 um.

30. The packaged micromirror array of claim 29, wherein the thickness of the micromirror plate is from 200 to 7300 angstroms.

31. The packaged micromirror array of claim 1, further comprising a light absorbing layer under the micromirrors to decrease light scatter through the gaps between the micromirrors.

32. The packaged micromirror array of claim 1, wherein from 64,000 to 2,000,000 micromirror are provided in the array.

33. The packaged micromirror array of claim 1, wherein from 2,000,000 to 3,000,000 micromirrors are provided in the array.

34. The packaged micromirror array of claim 1, having QXGA format.

35. The packaged micromirror array of claim 1, having UXGA format.

36. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirror is disposed in the package having the light transmissive window;

wherein the array of micromirror is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array; and

wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, and wherein the substrate, micromirror plates and hinges are disposed in different planes.

37. The packaged micromirror array of claim 36, further comprising bond wires at one end of the package electrically connecting the micromirror array to the package for actuation of the micromirrors.

38. The packaged micromirror array of claim 37, wherein the micromirrors are positioned on a lattice aligned at an angle to the sides of the rectangular array.

39. The packaged micromirror array of claim 36, wherein a mask is formed on the package window and extends around a periphery of the micromirror array.

40. The packaged micromirror array of claim 36, wherein a molecular scavenger is provided within the package.

41. The packaged micromirror array of claim 36, wherein a getter is provided within the package.

42. The packaged micromirror array of claim 41, wherein a stiction reducing agent is provided within the package.

43. The packaged micromirror array of claim 41, wherein the micromirror are capable of rotating at least +12 degrees to the ON position.

44. The packaged micromirror array of claim 41, wherein the package is a hermetic package.

45. The packaged micromirror array of claim 41, wherein the package is a partially hermetic package.

46. The packaged micromirror array of claim 41, wherein hinges of the micromirrors extend parallel to leading and trailing sides of the rectangular array.

47. The packaged micromirror array of claim 41, wherein the micromirror array has an area of from 1 cm² to 1 in².

48. The packaged micromirror array of claim 36, in HDTV format.

49. The packaged micromirror array of claim 36, wherein the micromirrors are positioned on a lattice aligned at an angle to the X and Y axes of the array.

50. The packaged micromirror array of claim 36, wherein a first gap is defined between the hinge and the micromirror plate, and a second gap is defined between the micromirror plate and the substrate.

51. The packaged micromirror array of claim 36, wherein a first gap is defined between the substrate and the hinge and a second gap is defined between the hinge and the micromirror plate.

52. The packaged micromirror array of claim 51, wherein a molecular scavenger is provided within the package.

53. The packaged micromirror array of claim 36, wherein the micromirrors comprise metal and a dielectric material, wherein the dielectric material is a nitride, carbide or oxide of silicon.

54. The packaged micromirror array of claim 36, wherein the micromirror array comprises circuitry and electrodes on a semiconductor substrate, and bond wires for electrically connecting the substrate to the package.

55. The packaged micromirror array of claim 36, wherein at least 1000 micromirrors are in the micromirror array.

56. The packaged micromirror array of claim 36, wherein each micromirror has a switching axis substantially parallel to at least one side of the array.

57. The packaged micromirror array of claim 56, wherein each micromirror has a switching axis that is at an angle of from 35 to 60 degrees to sides of the micromirror.

58. The packaged micromirror array of claim 57, wherein each micromirror comprises a hinge and micromirror plate that are disposed in different planes, and wherein the hinge has a width of from 0.1 to 10 um.

59. The packaged micromirror array of claim 58, wherein the thickness of the micromirror plate is from 200 to 7300 angstroms.

60. The packaged micromirror array of claim 36, further comprising a light absorbing layer under the micromirrors to decrease light scatter through the gaps between the micromirror.

61. The packaged micromirror array of claim 60, wherein from 64,000 to 2,000,000 micromirrors are provided in the array.

62. The packaged micromirror array of claim 60, wherein the micromirror has a resolution of 1,920,000 or higher.

63. The packaged micromirror array of claim 36, disposed within a projection system.

64. The packaged micromirror array of claim 63, where the projection system is a rear projection TV.

65. The packaged micromirror array of claim 36, wherein the package is hermetic and further comprises a getter within the package, and wherein the micromirrors are capable of rotating at least +12 degrees from a non-deflected state to the ON position, and wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, the hinges having a width of from 0.1 to 10 um, and wherein the substrate, micromirror plates and hinges are disposed in different planes, and further comprising a light absorbing layer under the micromirror to decrease light scatter through the gaps between the micromirrors.

66. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirror is disposed in the package having the light transmissive window;

wherein the array of micromirror is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array;

wherein a getter is provided within the package; and

wherein a stiction reducing agent is provided within the package.

67. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirror is disposed in the package having the light transmissive window;

wherein the array of micromirrors is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array;

wherein a getter is provided within the package; and

wherein the micromirrors are capable of rotating at least +12 degrees to the ON position.

68. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirrors is disposed in the package having the light transmissive window;

wherein the array of micromirror is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array; and

wherein the packaged micromirror array is in HDTV format.

69. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirror are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein thy array of micromirrors is disposed in the package having the light transmissive window;

wherein the array of micromirrors is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array;

wherein a getter is provided within the package; and

wherein the package is a hermetic package.

70. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirror is disposed in the package having the light transmissive window;

wherein the array of micromirrors is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array;

a light absorbing layer under the micromirrors to decrease light scatter through the gaps between the micromirrors; and

wherein from 64,000 to 2,000,000 micromirror are provided in the array.

71. A packaged micromirror array, comprising:

a package comprising an array of micromirrors, each micromirror having a four-sided shape defined by four micromirror sides;

wherein the micromirrors are capable of movement between an OFF state and an ON state with pulse width modulation for forming an image on a target;

the package further comprising a light transmissive window, wherein the array of micromirrors is disposed in the package having the light transmissive window;

wherein the array of micromirrors is a rectangular array;

wherein the four micromirror sides of each micromirror are not parallel to any sides of the rectangular array; and

wherein the package is hermetic and further comprises a getter within the package, and wherein the micromirrors are capable of rotating at least +12 degrees, from a non-deflected state to the ON position, and wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, the hinges having a width of from 0.1 to 10 um, and wherein the substrate, micromirror plates and hinges are disposed in different planes, and further comprising a light absorbing layer under the micromirrors to decrease light scatter through the gaps between the micromirrors.