Methods and apparatus for actuating displays

• US 20070216987A1
• Filed: 03/30/2007
• Published: 09/20/2007
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger, Payne, Richard, Gandhi, Jignesh, Fijol, John, Steyn, Jasper, Hagood, Nesbitt, Fike, Eugene
• Granted Patent: US 7,675,665 B2
• Time in Patent Office: Days
• US Class Current: 359/298
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

Abstract

This invention relates to display apparatuses having an array of light modulators and a plurality of apertures formed in a layer of material. Each light modulator corresponds to one or more apertures and has a portion which may overlap a corresponding aperture, where the size of the overlap is proportional to a distance between the array and the layer of material.

Claims

1. A display apparatus comprising:

a first substrate having a front-facing surface and a rear-facing surface;

a reflective aperture layer including a plurality of apertures disposed on the front-facing surface of the first substrate; and

a plurality of MEMS light modulators for modulating light directed towards the plurality of apertures to form an image.

2. The display apparatus of claim 1, wherein the first substrate comprises a light guide.

3. The display apparatus of claim 1, wherein the plurality of MEMS light modulators comprise shutter-based light modulators.

4. The display apparatus of claim 1, wherein the plurality of MEMS light modulators comprise electrowetting light modulators.

5. The display apparatus of claim 1 wherein the MEMS light modulators are disposed on the first substrate.

6. The display apparatus of claim 1 wherein the first substrate is transparent.

7. The display apparatus of claim 1, comprising a light guide positioned behind the first substrate, wherein the reflective aperture layer reflects light not passing through the plurality of apertures included in the reflective aperture layer back towards the light guide.

8. The display apparatus of claim 7, wherein the first substrate is in intimate contact with the light guide.

9. The display apparatus of claim 1, wherein the reflective aperture layer is formed from one of a mirror, a dielectric mirror, and a metallic film.

10. The display apparatus of claim 1, wherein the plurality of apertures correspond to respective light modulators of the plurality of light modulators.

11. The display apparatus of claim 1, wherein the first substrate is positioned such that the reflective aperture layer is proximate the plurality of light modulators.

12. The display apparatus of claim 1, wherein the first substrate is positioned with respect to a light guide so as to form a gap between the first substrate and the light guide.

13. The display apparatus of claim 12, comprising a fluid filling the gap.

14. The display apparatus of claim 13, wherein the fluid is air.

15. The display apparatus of claim 13, wherein the fluid has a first index of refraction and the light guide has a second index of refraction, and wherein the first index of refraction is less than that of the second index of refraction.

16. The display apparatus of claim 1, comprising an active matrix control matrix for controlling the plurality of MEMS light modulators, wherein the active matrix includes at least one switch corresponding respective MEMS light modulators.

17. The display apparatus of claim 1, comprising a second substrate positioned in front of the front-facing surface of the first substrate.

18. The display apparatus of claim 17, wherein the plurality of MEMS light modulators are formed on the second substrate.

19. The display apparatus of claim 17, wherein the plurality of MEMS light modulators are formed on a rear-facing surface of the second substrate.

20. The display apparatus of claim 17, comprising a control matrix formed on the second substrate for controlling the plurality of MEMS light modulators.

21. The display apparatus of claim 17, wherein the second substrate is transparent.

22. The display apparatus of claim 17, comprising mechanically interlocking features for maintaining lateral alignment between the first and second substrates.

23. The display apparatus of claim 22, wherein the mechanically interlocking features restrict relative lateral movement of the first and substrate to less than 5 microns in any dimension.

24. The display apparatus of claim 17, comprising an adhesive for maintaining lateral alignment between the first and second substrates.

25. The display apparatus of claim 24, wherein the adhesive restricts relative lateral movement of the first and substrate to less than 5 microns in any dimension.

26. The display apparatus of claim 17, wherein the first substrate is positioned between a light guide and the second substrate.

27. The display apparatus of claim 17, wherein the first substrate is positioned with respect to the second substrate so as to form a gap between the first substrate and the second substrate.

28. The display apparatus of claim 27, comprising spacers for maintaining the gap.

29. The display apparatus of claim 28, comprising a fluid filling the gap.

30. The display apparatus of claim 29, comprising a liquid filling the gap.

31. The display apparatus of claim 29, wherein the fluid is a lubricant.

32. The display apparatus of claim 29, wherein the fluid has a first index of refraction and the substrate has a second index of refraction, and wherein the first index of refraction is greater than or substantially equal to that of the second index of refraction.

69. The display apparatus of claim 24, wherein the adhesive comprises a heat-reflowable material.

33. A display apparatus comprising:

a first substrate;

a second substrate;

an array of MEMS light modulators formed on one of the first and second substrates; and

a spacer located within the interior of the array, integrally formed from or connected to the first substrate at a first end and connected to a second substrate at a second end.

34. The display apparatus of claim 33, wherein the connection of the spacer to one of the first and second substrates comprises a connection to a stack of at least one thin film deposited on the substrate.

35. The display apparatus of claim 34, wherein the thin film comprises one of a reflective aperture layer, a light absorbing layer, and a color filter.

36. The display apparatus of claim 33, wherein the spacer is etched from the first substrate.

37. The display apparatus of claim 33, wherein the spacer is etched from a film deposited on the first substrate.

38. The display apparatus of claim 33, wherein the first substrate and second substrates are substantially rigid.

39. The display apparatus of claim 33, wherein the first substrate and second substrates are substantially flexible.

40. The display apparatus of claim 33, wherein one of the first substrate and the second substrate is substantially rigid, and the other of the first substrate and the second substrate is substantially flexible.

41. The display apparatus of claim 33, wherein the spacer is formed from an insulative material.

42. The display apparatus of claim 33, wherein the first substrate includes a front surface of a display device.

43. The display apparatus of claim 33, wherein the second substrate includes a front surface of a display device.

44. The display apparatus of claim 33, comprising a light guide distinct from the first and second substrates.

45. The display apparatus of claim 33, comprising a plurality of additional spacers, wherein the spacer and the plurality of additional spacers are positioned within the array with a spacer density less than or equal to one spacer per four light modulators.

46. The display apparatus of claim 33, comprising a plurality of additional spacers, wherein the MEMS light modulators correspond to respective display pixels, and wherein the each of the respective display pixels includes at least one spacer.

47. The display apparatus of claim 33, wherein the spacer forms an electrical connection between an electrical component on the first substrate to an electrical component on the second substrate.

48. The display apparatus of claim 33, wherein the spacer is formed from a polymer.

49. The display apparatus of claim 33, wherein the spacer is formed from a metal.

50. The display apparatus of claim 33, wherein the MEMS light modulators are configured to selectively obstruct the passage of light.

51. The display apparatus of claim 50, wherein the MEMS light modulators comprises shutter-based light modulators.

52. The display apparatus of claim 50, wherein the MEMS light modulators include electrowetting-based light modulators.

53. The display apparatus of claim 33, wherein the MEMS light modulators selectively extract light from a light guide.

54. The display apparatus of claim 33, wherein the spacer limits a range of motion of a component in one of the MEMS light modulators.

55. The display apparatus of claim 33, wherein the spacer interfits with an aligning element formed on the second substrate.

56. The display apparatus of claim 33, comprising a fluid filling a gap between the first substrate and the second substrate.

57. The display apparatus of claim 56, wherein the fluid comprises a lubricant.

58. The display apparatus of claim 33, wherein at least one of the first substrate and the second substrate are substantially transparent.

59. The display apparatus of claim 33, wherein the spacer is between about 1 micron and about 10 microns tall.

60. A display apparatus comprising:

a first transparent substrate;

a second transparent substrate on which an array of light modulators are formed;

a spacing element formed from a heat-reflowable material aligning the first transparent layer with the second transparent layer.

61. The display apparatus of claim 60, wherein the heat-reflowable material obtains a substantially liquid state between about 150 degrees and about 400 decrees Centigrade.

62. The display apparatus of claim 60, wherein the spacing element serves as an adhesive joining the first transparent substrate to the second transparent substrate.

63. The display apparatus of claim 60, comprising an reflective aperture layer formed on one of the first transparent substrate and the second transparent substrate.

64. The display apparatus of claim 60, wherein the light modulators comprise MEMS light modulators.

65. The display apparatus of claim 60, wherein the spacing element is disposed on a periphery of the array of light modulators.

66. The display apparatus of claim 60, wherein the spacing element is disposed within the array of light modulators.

67. The display apparatus of claim 60, wherein the heat-reflowable material comprises one of a metal, a plastic, and a glass.

68. The display apparatus of claim 60, wherein the heat-reflowable material, when in a substantially liquid state, wets the surface of features on both the first transparent substrate and the second transparent substrate.