Systems and methods using interferometric optical modulators and diffusers

• US 7,710,636 B2
• Filed: 08/22/2005
• Issued: 05/04/2010
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence
• Primary Examiner(s): Ben; Loha
• Application Number:
  US11/209,143
• Publication Number:
  US 20060066511A1
• Time in Patent Office: 1,716 Days
• Field of Search: 359/290, 359/291, 359/295, 359/298, 359/13, 359/15, 359/22, 359/24, 359/245, 359/247, 359/254, 359/260, 359/578, 359/599, 359/292, 359/237, 359/238, 359/321, 359/886, 345/32, 345/85, 345/173, 345/33, 345/520, 349/58, 349/120, 349/114, 349/187, 356/450, 356/486, 356/493, 356/502, 356/517, 385/3, 362/331, 362/343, 362/355, 362/619, 327/108, 324/202, 324/527, 438/29, 438/48, 438/52, 257/709, 73/407
• US Class Current: 359/295
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

Various embodiments include interferometric optical modulators comprising a substrate layer having a thickness between about 0.1 mm to about 0.45 mm thick and a method for manufacturing the same. The interferometric modulator can be integrated together with a diffuser in a display device. The thin substrate permits use of a thicker substrate. The thinner substrate may increase resolution and reduce overall thickness of the inteferometric modulator. The thicker diffuser may provide increased diffusion and durability.

Claims

1. A display comprising a plurality of display elements, each of said display elements comprising:

a movable reflector;

a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity, said movable reflector and said partial reflector separated by a gap; and

a diffuser portion disposed forward the movable and partial reflectors,

wherein said movable reflector is configured to move with respect to said partial reflector and to alter said optical resonator cavity in response to an electrical signal, and

wherein (i) the plurality of display elements has a reflectivity at a viewing angle of about 45°

that is greater than about 75% of the reflectivity of the plurality of display elements when viewed from normal and (ii) the diffuser portions are disposed sufficiently close to the partial reflectors such that the plurality of display elements achieve a contrast of greater than about 5 to 1 while using a displayed test pattern of alternating white and black lines of a spatial period of less than about 0.45 millimeter.

2. The display of claim 1, wherein said diffuser portion is disposed within about 0.45 millimeter of said partial reflector.

3. The display of claim 1, wherein said diffuser portion is disposed within about 0.25 millimeter of said partial reflector.

4. The display of claim 1, wherein said diffuser portion is disposed within about 0.15 millimeter of said partial reflector.

5. The display of claim 1, wherein said movable reflector and said partial reflector are disposed on a first side of a substrate and said diffuser portion is disposed on a second side of said substrate.

6. The display of claim 5, wherein said substrate has a thickness of less than about 0.45 millimeter.

7. The display of claim 5, wherein said display elements are configured such that said first side of said substrate is distal to a viewer of said display and said second side of said substrate is proximal to said viewer.

8. The display of claim 1, wherein the spatial period is less than about 0.3 millimeter.

9. The display of claim 8, wherein the spatial period is less than about 0.2 millimeter.

10. The display of claim 8, wherein the spatial period is less than about 0.1 millimeter.

11. The display of claim 1, further comprising a substrate comprised of at least one of glass, plastic, silica, and alumina.

12. The display of claim 1, wherein said diffuser portions for said plurality of display elements comprise a plurality of separate diffuser elements.

13. The display of claim 12, wherein said diffuser portion comprises a diffractive optical element.

14. The display of claim 12 wherein said diffuser portion has optical power.

15. The display of claim 14, wherein said diffuser portion has negative optical power.

16. The display of claim 1, further comprising:

a processor that is in electrical communication with said display elements, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

17. The display of claim 16, further comprising a driver circuit configured to send at least one signal to said display elements.

18. The display of claim 17, further comprising a controller configured to send at least a portion of said image data to said driver circuit.

19. The display of claim 16, further comprising an image source module configured to send said image data to said processor.

20. The display of claim 19, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

21. The display of claim 16, further comprising an input device configured to receive input data and to communicate said input data to said processor.

22. The display of claim 1, wherein each of said display elements further comprises an electrode portion configured to cause said movable reflector to move with respect to said partial reflector in response to said electrical signal, said electrode portion disposed on the same side of said gap as said partial reflector.

23. The display of claim 1, wherein said display elements are configured such that light incident on said display passes through said diffuser portion before entering said optical resonator cavity.

24. The display of claim 1, wherein said display comprises a reflective display.

25. A display comprising a plurality of display elements, each of said display elements comprising:

means for spatially modulating light by interferometrically modulating reflectivity, said spatial light modulating means having a maximum resolution less than about 0.45 millimeter; and

means for diffusing said light,

wherein (i) in one state, said plurality of display elements have a reflectivity at a viewing angle of about 45°

that is greater than about 75% of the reflectivity of the display elements when viewed from normal, and (ii) said plurality of display elements produce a display contrast greater than about 5 to 1 for a test pattern comprising alternating white and black lines with said maximum resolution of said spatial light modulating means.

26. The display of claim 25, wherein the spatial light modulating means comprises:

a movable reflector; and

a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity, said movable reflector and said partial reflector separated by a gap,

wherein said movable reflector is configured to move with respect to said partial reflector to alter the gap in said optical resonator cavity in response to an electrical signal.

27. The display of claim 26, wherein the diffusing means comprises a diffuser disposed within about 0.45 millimeter or less of the partial reflector.

28. The display of claim 26, further comprising means for conducting electricity, said conducting means configured to cause said movable reflector to move with respect to said partial reflector in response to said electrical signal, said conducting means disposed on the same side of said gap as said partial reflector.

29. The display of claim 25, further comprising means for focusing light.

30. The display of claim 29, wherein the focusing means comprises at least one of a holographic lens, a diffractive lens, and a Fresnel lens.

31. The display of claim 25, wherein said spatial light modulating means is disposed on a first side of a substrate and said diffusing means are disposed on a second side of said substrate.

32. The display of claim 25, wherein said display elements are configured such that light incident on said display passes through said diffusing means before being received by said spatial light modulating means.

33. The display of claim 25, wherein said display comprises a reflective display.

34. A method of manufacturing a display element, said method comprising:

forming a movable reflector;

forming a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity, said movable reflector and said partial reflector separated by a gap such that said movable reflector can move toward said partial reflector to modulate said optical resonator cavity;

forming a diffuser disposed within about 0.45 millimeter or less of the partial reflector; and

forming an electrode portion configured to cause said movable reflector to move with respect to said partial reflector,

wherein said movable and partial reflectors are formed on a substrate comprising at least one of glass, plastic, silica, and alumina.

35. The method of claim 34, wherein forming said diffuser comprises disposing said diffuser within about 0.35 millimeter of said partial reflector.

36. The method of claim 34, wherein forming said diffuser comprises disposing said diffuser within about 0.25 millimeter of said partial reflector.

37. The method of claim 34, wherein forming said diffuser comprises disposing said diffuser within about 0.15 millimeter of said partial reflector.

38. The method of claim 34, wherein forming the diffuser comprises forming at least one of a holographic lens or a diffractive lens.

39. The method of claim 34, wherein forming the diffuser comprises forming a Fresnel lens.

40. A display comprising a plurality of display elements, each manufactured using the method of claim 34.

41. The display of claim 40, wherein said plurality of display elements are configured to achieve a contrast of greater than about 5 to 1 for a test pattern comprising alternating white and black rows of said plurality of display elements, wherein the plurality of display elements have a reflectivity at a viewing angle of about 45°

that is greater than about 75% of the reflectivity of the display elements when viewed from normal, and wherein a spatial resolution of the plurality of display elements is less than about 0.3 millimeter.

42. The display of claim 41, wherein the spatial resolution is less than about 0.2 millimeter.

43. The display of claim 41, wherein the spatial resolution is less than about 0.1 millimeter.

44. The method of claim 34, wherein said movable and partial reflectors are formed on a first side of said substrate and said diffuser is formed on a second side of said substrate.

45. The method of claim 34, wherein said electrode portion is formed on the same side of said gap as said partial reflector.

46. A display comprising a plurality of display elements, each of said display elements comprising:

a movable reflector;

a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity,

said movable reflector configured to move with respect to said partial reflector to alter said optical resonator cavity in response to an electrical signal; and

a substrate, said movable reflector, and said partial reflector disposed on one side of said substrate, said substrate having a thickness of about 0.45 millimeter or less.

47. The display of claim 46, wherein said substrate has a thickness of about 0.4 millimeter or less.

48. The display of claim 46, wherein said substrate has a thickness of about 0.3 millimeter or less.

49. The display of claim 46, wherein said substrate has a thickness of about 0.2 millimeter or less.

50. The display of claim 46, wherein said substrate has a thickness of about 0.1 millimeter or less.

51. The display of claim 46, further comprising a diffuser having a thickness of no more than about 0.4 millimeter.

52. The display of claim 51, wherein said plurality of display elements are arranged in rows and columns and have a spatial resolution less than about 0.3 millimeter and a reflectivity at a viewing angle of about 45°

that is greater than about 75% of the reflectivity when viewed from normal.

53. The display of claim 52, wherein said diffuser is disposed a distance from said partial reflector to provide said plurality of display elements with a contrast of greater than about 5 to 1 for a test pattern of alternating white and black rows or columns.

54. The display of claim 46, further comprising a diffuser portion disposed on an opposite side of said substrate from said movable and partial reflectors.

55. The display of claim 54, wherein said display elements are configured such that light incident on said display passes through said diffuser portion before entering said optical resonator cavity.

56. The display of claim 46, wherein said display comprises a reflective display.

57. The display of claim 46, further comprising an electrode portion configured to cause said movable reflector to move with respect to said partial reflector in response to said electrical signal, said electrode portion disposed on the same side of said optical resonator cavity as said partial reflector.

58. A display comprising a plurality of display elements, each of said display elements comprising:

a movable reflector;

a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity, said movable reflector and said partial reflector separated by a gap;

a diffuser portion disposed forward the movable and partial reflectors,

wherein said movable reflector is configured to move with respect to said partial reflector and to alter said optical resonator cavity in response to an electrical signal,

wherein said diffuser portion is disposed within about 0.45 millimeter of said partial reflector, and

wherein said movable reflector and said partial reflector are disposed on a first side of a substrate and said diffuser portion is disposed on a second side of said substrate.

59. The display of claim 58, wherein said diffuser portion is disposed within about 0.35 millimeter of said partial reflector.

60. The display of claim 58, wherein said diffuser portion is disposed within about 0.25 millimeter of said partial reflector.

61. The display of claim 58, wherein said diffuser portion is disposed within about 0.15 millimeter of said partial reflector.

62. The display of claim 58, further comprising an electrode portion configured to cause said movable reflector to move with respect to said partial reflector in response to said electrical signal, said electrode portion disposed on the same side of said gap as said partial reflector.

63. The display of claim 58, wherein said display elements are configured such that light incident on said display passes through said diffuser portion before entering said optical resonator cavity.

64. The display of claim 58, wherein said display comprises a reflective display.

65. A display element comprising:

a movable reflector;

a partial reflector positioned at a distance from the movable reflector thereby forming an optical resonator cavity, said movable reflector and said partial reflector separated by a gap; and

a diffuser portion disposed forward the movable and partial reflectors,

wherein said movable reflector is configured to move with respect to said partial reflector and to alter said optical resonator cavity in response to an electrical signal,

wherein said diffuser portion is disposed within about 0.45 millimeter of said partial reflector, and

wherein said movable reflector and said partial reflector are disposed on a first side of a substrate and said diffuser portion is disposed on a second side of said substrate.

66. The display element of claim 65, wherein said diffuser portion is disposed within about 0.35 millimeter of said partial reflector.

67. The display element of claim 65, wherein said diffuser portion is disposed within about 0.25 millimeter of said partial reflector.

68. The display element of claim 65, wherein said diffuser portion is disposed within about 0.15 millimeter of said partial reflector.

69. The display element of claim 65, further comprising an electrode portion configured to cause said movable reflector to move with respect to said partial reflector in response to said electrical signal, said electrode portion disposed on the same side of said gap as said partial reflector.

70. The display element of claim 65 configured such that light incident on said display element passes through said diffuser portion before entering said optical resonator cavity.

71. The display element of claim 65, wherein said display element comprises a reflective display element.