Display apparatus with improved contrast ratio
View Patent ↗Disclosed herein is a micromirror-based display system having an improved contrast ratio with the deflection of the micromirrors accomplished through one addressing electrode associate with the micromirror.
1. A projection system, comprising:
a light source providing illumination light for the projection system;
a spatial light modulator comprising an array of micromirror devices, wherein each micromirror device comprises;
a deflectable and reflective mirror plate; and
a single addressing electrode disposed proximate to the mirror plate for receiving pulse-width-modulation data so as to deflect the mirror plate;
an optical element for directing light onto the spatial light modulator;
wherein the projection system has a contrast ratio of 1200:1 or more.
2. The system of claim 1 , wherein the contrast ratio is 1500:1 or more.
3. The system of claim 1 , wherein the contrast ratio is 2000:1 or more.
4. The system of claim 1 , further comprising:
a color filter and a lightpipe.
5. The system of claim 4 , wherein the color filter is positioned between the light source and lightpipe.
6. The system of claim 4 , wherein the color filter is positioned after the light source and lightpipe at a propagation path of illumination light from the light source.
7. The system of claim 1 , wherein the mirror plate is operable to rotate to an ON state angle in response to an electrostatic field between the mirror plate and addressing electrode; but rotate to an OFF state angle under a mechanical restoration force in a deformnable hinge of the micromirror.
8. The system of claim 7 , wherein the ON state angle is from 14° to 20° relative to a substrate on which the micromirror is formed.
9. The system of claim 7 , wherein the OFF state angle is from −1° to −6° relative to a substrate on which the micromirror is formed.
10. The system of claim 7 , wherein a difference between the ON and OFF state angles is from 12° to 18°.
11. The system of claim 7 , wherein a difference between the ON and OFF state angles is from 16° to 22°.
12. The system of claim 7 , wherein a difference between the ON and OFF state angles is 22° or lower.
13. The system of claim 1 , wherein the mirror plate is attached to a deformable hinge and is at a different plane than the deformable hinge.
14. The system of claim 13 , wherein the hinge is disposed at a side of the mirror plate opposite to the incident light.
15. The system of claim 13 , wherein each micromirror further comprises: a post to which the deformable hinge is affixed thus held thereby.
16. The system of claim 15 , wherein the post comprises a light absorbing material coated thereon for absorbing scattered light.
17. The system of claim 15 , wherein the array of micromirror devices further comprises micromirror device without a post.
18. The system of claim 1 , wherein a gap between adjacent micromirrors in the micromirror array is 0.5 micron or less.
19. The system of claim 1 , wherein the gap between adjacent micromirrors in the micromirror array is from 0.1 to 0.5 micron.
20. The system of claim 1 , further comprising: another electrode having thereon a constant bias voltage in operation.
21. The system of claim 1 , further comprising:
a condensing lens whose f-number is from f/1.8 to f/4 with f being a focal length of the condensing lens.
22. The system of claim 21 , wherein the f-number of the condensing lens is f/2.4.
23. The system of claim 1 , further comprising:
a projection lens whose f-number is from f/1.8 to f/4 with f being a focal length of the condensing lens.
24. The system of claim 23 , wherein the f-number of the projection lens is f/2.4.
25. The system of claim 1 , wherein the mirror plate has a zigzagged edge.
26. The system of claim 22 , wherein the illumination light is incident towards the zigzagged edge of the mirror plate.
27. The system of claim 1 , wherein the mirror plate comprises a reflecting surface of a metallic material.
28. The system of claim 27 , wherein the metallic material is gold.
29. The system of claim 27 , wherein the metallic material is silver.
30. The system of claim 27 , wherein the metallic material is aluminum.
31. The system of claim 1 , wherein the mirror plate comprises a tapered side edge.
32. The system of claim 1 , wherein the micromirror is positioned in a device package that comprises a package substrate and a package cover between which the micromirror array devices are positioned.
33. The system of claim 32 , wherein the package cover is transmissive to the illumination light from the light source; and is positioned not parallel to the mirror plates at a non-deflected state.
34. The system of claim 32 , wherein the package cover comprises a light absorbing mask for absorbing the illumination light incident onto the circumference of the package cover.
35. The system of claim 32 , wherein the package further comprises a light absorbing material.
36. The system of claim 35 , wherein the light absorbing material is on the package substrate.
37. The system of claim 35 , wherein the light absorbing material is on a side wall of the package substrate.
38. The system of claim 35 , wherein the package cover is bonded to the package substrate.
39. The system of claim 1 , wherein the system is a rear-projection television.
40. The system of claim 1 , wherein the system is a front-projection television.
41. A projection system, comprising:
a light source;
a spatial light modulator comprising an array of micromirror devices, wherein each micromirror device comprises a deflectable and reflective mirror plate that is attached to a deformable hinge, and is operable to rotate to an ON state angle in response to an electrostatic force, but to an OFF state angle under a mechanical restoration force in the deformable hinge; and
an optical element for directing light onto the spatial light modulator;
wherein the system has a contrast ratio of 1200:1 or more.
42. The system of claim 41 , wherein a difference between the ON and OFF state angles is from 12° to 18°.
43. The system of claim 41 , wherein a difference between the ON and OFF state angles is from 16° to 22°.
44. The system of claim 41 , wherein a difference between the ON and OFF state angles is 22° or less.
45. The system of claim 41 , wherein each mirror plate is associated with one addressing electrode for deflecting the mirror plate to the ON state.
46. The system of claim 41 , wherein the mirror plate is at a different plane than the hinge when the mirror plate is not deflected.
47. The system of claim 41 , wherein the contrast ratio is 1500:1 or higher.
48. The system of claim 41 , wherein the contrast ratio is 2000:1 or higher.
49. The system of claim 41 , wherein the system is a rear-projection television.
50. The system of claim 41 , wherein the system is a front-projection television.
51. A projection system, comprising:
a light source;
a spatial light modulator comprising an array of micromirror devices, wherein each micromirror device comprises a deflectable and reflective mirror plate that is attached to a deformable hinge, and is operable to rotate to an ON state angle and an OFF state angle, wherein
a difference between the ON and OFF state angles is from 12° to 22°; and
an optical element for directing light onto the spatial light modulator;
wherein the system has a contrast ratio of 1200:1 or more.
52. The system of claim 51 , wherein the mirror plate is operable to rotate to the ON state angle in response to an electrostatic force, but to the OFF state angle under a mechanical restoration force in the deformable hinge.
53. The system of claim 51 , wherein the contrast ratio is 1500:1 or higher.
54. The system of claim 51 , wherein the contrast ratio is 2000:1 or higher.
55. The system of claim 51 , wherein the mirror plate is at a different plane than the deformable hinge.
56. The system of claim 51 , wherein the system is a rear-projection television.
57. The system of claim 51 , wherein the system is a front-projection television.
58. A projection system, comprising:
a light source providing light for the system;
a spatial light modulator comprising an array of micromirror devices, wherein each micromirror device has a mirror plate attached to a deformable hinge, and is operable to rotate to an ON state angle that is 14° degrees or more relative to a non-deflected state; and
an optical element for directing the light onto the spatial light modulator,
wherein the display system has a contrast ratio of 1200:1 or higher.
59. The projection system of claim 58 , wherein the mirror plate is associated with one single electrode for addressing and rotating the mirror plate.
60. The projection system of claim 59 , wherein the addressing electrode is on a semiconductor substrate formed thereon an electric circuitry.
61. The projection system of claim 58 , wherein the ON state angle is 16° or more.
62. The projection system of claim 58 , wherein the ON state angle is 18° or more.
63. The projection system of claim 58 , wherein the mirror plate is operable to rotate to an OFF state angle relative to the non-deflected state.
64. The projection system of claim 58 , wherein the OFF state angle is 0 degree.
65. The projection system of claim 58 , wherein the OFF state angle is from 1° to −6°.
66. The projection system of claim 58 , wherein the OFF state angle is from −1° to −5°.
67. The projection system of claim 58 , wherein the contrast ratio is 1500:1 or higher.
68. The projection system of claim 58 , wherein the contrast ratio is 2000:1 or higher.
69. The projection system of claim 58 , wherein the mirror plate is in a separate plane from that of the deformable hinge.
70. A projection system, comprising:
a light source providing light for the system;
a spatial light modulator comprising an array of micromirror devices, wherein each micromirror device further comprises:
a mirror plate; and
a deformable hinge;
wherein the mirror plate is attached to the hinge such that the maximum angle achievable by the mirror plate rotating in a first direction is different from that of the mirror plate rotating in a second direction opposite to the first direction; and
an optical element for directing the light onto the spatial light modulator,
wherein the display system has a contrast ratio of 1200:1 or higher.
71. The projection system of claim 70 , wherein the mirror plate is associated with one single electrode for addressing and rotating the mirror plate.
72. The projection system of claim 71 , wherein the addressing electrode is on a semiconductor substrate formed thereon an electric circuitry.
73. The projection system of claim 71 , wherein the achievable maximum angle in the first direction is an ON state angle of 16° or more.
74. The projection system of claim 73 , wherein the ON state angle is 18° or more.
75. The projection system of claim 71 , wherein the achievable maximum angle in the second direction is an OFF state angle that is 0 degree.
76. The projection system of claim 71 , wherein the achievable maximum angle in the second direction is an OFF state angle that is −1° to −5°.
77. The projection system of claim 71 , wherein the contrast ratio is 1500:1 or higher.
78. The projection system of claim 71 , wherein the contrast ratio is 2000:1 or higher.
79. The projection system of claim 71 , wherein the mirror plate is in a separate plane from that of the deformable hinge.