Internal optical isolation structure for integrated front or back lighting

• US 7,855,827 B2
• Filed: 10/06/2006
• Issued: 12/21/2010
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lewis, Alan, Xu, Gang, Gally, Brian, Mienko, Mark
• Primary Examiner(s): Sugarman; Scott J
• Assistant Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US11/544,978
• Publication Number:
  US 20080084602A1
• Time in Patent Office: 1,537 Days
• Field of Search: 359290-292, 359/245, 359223-225, 359/198, 359260-263, 359/298, 359301-303, 359317-318, 359/295
• US Class Current: 359/296
• 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: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

An optical isolation structure is incorporated into a display between the display elements and the transparent substrate for the display elements. The optical isolation structure reflects light rays within the substrate that impact the structure at high angles relative to normal to the structure, thereby permitting the substrate to be used as an integrated light guide for distributing light over the display from a light source on the edge of the substrate. The optical isolation structure may include a single layer having an index of refraction less than the substrate or a plurality of thin-film interference layers.

Claims

1. A display with integrated front or back light guide, comprising:

a plurality of display elements;

an optical isolation structure disposed over the display elements, wherein the optical isolation structure comprises at least a first, second, and third non-gaseous material layer; and

a transparent substrate disposed over the optical isolation structure, wherein the first material layer has an index of refraction greater than the index of refraction of the transparent substrate, the second material layer has an index of refraction less than the index of refraction of the first material layer, and the third material layer has an index of refraction greater than the index of refraction of the second material layer, and wherein the optical isolation structure is adapted to reflect more light incident on the optical isolation structure from within the substrate at non-zero angles of incidence relative to normal than at normal incidence.

2. The display of claim 1, wherein the optical isolation structure is adapted to reflect more than 40% of light incident on the optical isolation structure from within the substrate at angles greater than 70 degrees relative to normal to the optical isolation structure.

3. The display of claim 1, wherein the display elements comprise interferometric modulators.

4. The display of claim 1, wherein the display elements comprise liquid crystal elements.

5. The display of claim 1, wherein the display elements comprise electrophoretic elements.

6. The display of claim 1, the optical isolation structure comprising multiple interference layers.

7. The display of claim 1, wherein the material layers are dielectric material.

8. The display of claim 1, wherein the transparent substrate comprises glass.

9. The display of claim 1, comprising a light source positioned to direct light into an edge of the substrate.

10. The display of claim 9, wherein the light source is configured to direct light into the edge of the substrate substantially at angles greater than about 70 degrees relative to normal to the layers.

11. The display of claim 1, comprising a plurality of light redirectors disposed adjacent to the transparent substrate, the light redirectors configured to redirect light incident on the light directors into the display elements.

12. The display of claim 11, wherein the light redirectors are configured to redirect light incident on the light directors at angles greater than 70 degrees relative to normal to the layers into the display elements.

13. The display of claim 11, wherein the light redirectors are disposed in a film disposed on the substrate.

14. The display of claim 13, wherein the light redirectors comprise angled surfaces of the film.

15. The display of claim 1, wherein the optical isolation structure is adapted to transmit more than 80% of light incident on the optical isolation structure at angles less than 30 degrees relative to normal to the optical isolation structure.

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 first controller configured to send at least one signal to said display elements; and

a second controller configured to send at least a portion of said image data to said first controller.

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

19. The display of claim 18, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

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

21. The display of claim 1, wherein the display elements comprise microelectromechanical systems.

22. The display of claim 1, wherein the display is a reflective display.

23. The display of claim 1, wherein the display elements comprise a fixed partially reflective layer and a movable reflective layer.

24. The display of claim 1, wherein the substrate supports the display elements and the optical isolation structure.

25. The display of claim 1, wherein the substrate is adjacent to the first material layer.

26. The display of claim 1, wherein the first material layer is disposed over the substrate, the second material layer is disposed over the first material layer, and the third material layer is disposed over the second material layer.

27. A display with integrated front or back light guide, comprising:

a plurality of display elements;

an optical isolation structure disposed over the display elements, wherein the optical isolation structure comprises at least a first, second, and third dielectric layer; and

a transparent substrate disposed over the optical isolation structure, wherein the first dielectric layer has an index of refraction greater than the index of refraction of the transparent substrate, the second dielectric layer has an index of refraction less than the index of refraction of the first dielectric layer, and the third dielectric layer has an index of refraction greater than the index of refraction of the second dielectric layer, and wherein the optical isolation structure is adapted to reflect more light incident on the optical isolation structure from within the substrate at non-zero angles of incidence relative to normal than at normal incidence.

28. The display of claim 27, wherein the optical isolation structure is adapted to reflect more than 40% of light incident on the optical isolation structure from within the substrate at angles greater than 70 degrees relative to normal to the optical isolation structure.

29. The display of claim 27, wherein the display elements comprise microelectromechanical systems.

30. The display of claim 27, wherein the display is a reflective display.

31. The display of claim 27, wherein the display elements comprise a fixed partially reflective layer and a movable reflective layer.

32. The display of claim 27, wherein the substrate supports the display elements and the optical isolation structure.

33. The display of claim 27, wherein the substrate is adjacent to the first dielectric layer.

34. The display of claim 27, wherein the first dielectric layer is disposed over the substrate, the second dielectric layer is disposed over the first dielectric layer, and the third dielectric layer is disposed over the second dielectric layer.

35. A display, comprising:

a plurality of display elements; and

at least a first, second and third interference layer disposed over the display elements, wherein the interference layers are adapted to reflect more than 40% of light incident on the layers at angles greater than 70 degrees relative to normal to the layers, wherein the first interference layer has an index of refraction greater than 1.5109, the second interference layer has an index of refraction less than the index of refraction of the first interference layer, and the third interference layer has an index of refraction greater than the index of refraction of the second interference layer.

36. The display of claim 35, wherein the display elements comprise interferometric modulators.

37. The display of claim 35, wherein the display elements comprise liquid crystal elements.

38. The display of claim 35, wherein the display elements comprise electrophoretic elements.

39. The display of claim 35, wherein each interference layer is a dielectric material.

40. The display of claim 35, wherein the interference layers are adapted to transmit more than 80% of light incident on the layers at angles less than 30 degrees relative to normal to the layers.

41. The display of claim 35, wherein the display elements comprise microelectromechanical systems.

42. The display of claim 35, wherein the display is a reflective display.

43. The display of claim 35, wherein the display elements comprise a fixed partially reflective layer and a movable reflective layer.

44. The display of claim 35, wherein the third interference layer is disposed over the display elements, the second interference layer is disposed over the third interference layer, and the first interference layer is disposed over the second interference layer.

45. A light guide, comprising:

a transparent substrate; and

a plurality of material layers disposed on the transparent substrate, wherein the plurality of material layers comprise a first material layer disposed over the transparent substrate having an index of refraction greater than the transparent substrate, a second material layer disposed over the first material layer having an index of refraction lower than the first material layer, and a third material layer disposed over the second material layer having an index of refraction greater than the second material layer, wherein the combined plurality of material layers is adapted to reflect more than 40% of light incident on the plurality of material layers within the substrate at angles greater than 70 degrees relative to normal to the plurality of material layers.

46. The light guide of claim 45, wherein the transparent substrate is glass.

47. The light guide of claim 45, wherein the material layers are interference layers.

48. The light guide of claim 45, comprising a plurality of light redirectors disposed on the transparent substrate opposite the plurality of material layers, the light redirectors configured to redirect light incident on the light redirectors at angles greater than 60 degrees relative to normal to the layers through the material layers at angles less than 60 degrees relative to normal to the layers.

49. The light guide of claim 48, wherein the light redirectors are disposed in a film disposed on the substrate.

50. The light guide of claim 49, wherein the light redirectors comprise angled surfaces of the film.

51. The light guide of claim 45, wherein the combined plurality of material layers are adapted to transmit more than 80% of light incident on the plurality of material layers at angles less than 30 degrees relative to normal to the plurality of material layers.

52. A display, comprising:

means for displaying image content;

means disposed over the displaying means for reflecting light; and

means disposed over the reflecting means for propagating light, wherein the reflecting means comprises at least a first, second, and third material layer, wherein the first material layer has an index of refraction greater than the index of refraction of the propagating means, the second material layer has an index of refraction less than the index of refraction of the first material layer, and the third material layer has an index of refraction greater than the index of refraction of the second material layer, and wherein the reflecting means is adapted to reflect more light incident on the reflecting means from within the propagating means at non-zero angles of incidence relative to normal than at normal incidence.

53. The display of claim 52, wherein the displaying means comprise a plurality of display elements.

54. The display of claim 52, wherein the first, second, and third material layers comprise interference layers.

55. The display of claim 52, wherein the first, second, and third material layers comprise dielectric layers.

56. The display of claim 52, wherein the propagating means is a transparent substrate.

57. The display of claim 56, wherein the transparent substrate is glass.

58. The display of claim 52, wherein the displaying means comprises interferometric modulators.

59. The display of claim 52, wherein the propagating means supports the displaying means and the reflecting means.

60. The display of claim 52, wherein the propagating means is adjacent to the first material layer.

61. The display of claim 52, wherein the first material layer is disposed over the propagating means, the second material layer is disposed over the first material layer, and the third material layer is disposed over the second material layer.