Internal optical isolation structure for integrated front or back lighting

• US 20080084602A1
• Filed: 10/06/2006
• Published: 04/10/2008
• 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
• Granted Patent: US 7,855,827 B2
• Time in Patent Office: Days
• 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 one non-gaseous material layer; and

a transparent substrate disposed over the optical isolation structure, wherein the material layer has an index of refraction less than the index of refraction of the transparent substrate.

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 2, the optical isolation structure comprising multiple non-gaseous layers.

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

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

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

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

9. The display of claim 1, wherein the material layer is a dielectric material.

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

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

12. The display of claim 11, 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.

13. 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.

14. The display of claim 13, 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.

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

16. The display of claim 15, wherein the light redirectors comprise angled surfaces of the film.

17. 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.

18. The display of claim 1, wherein the optical isolation structure is configured such that total internal reflection occurs between the substrate and the optical isolation structure.

19. 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.

20. The display of claim 19, 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.

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

22. The display of claim 21, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

23. The display of claim 19, further comprising an input device configured to receive input data and to communicate said input data to said processor.

4. The display of 3, wherein at least one of the layers has an index of refraction greater than the index of refraction of the substrate.

24. 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 one or more dielectric layers; and

a transparent substrate disposed over the optical isolation structure.

25. The display of claim 24, wherein at least one of said material layers has an index of refraction less than the index of refraction of the transparent substrate.

26. The display of claim 24, 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.

27. A display, comprising:

a plurality of display elements; and

one or more interference layers 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.

28. The display of claim 27, wherein the display elements comprise interferometric modulators.

29. The display of claim 27, wherein the display elements comprise liquid crystal elements.

30. The display of claim 27, wherein the display elements comprise electrophoretic elements.

31. The display of claim 27, wherein the interference layers comprise a plurality of layers, wherein at least one of the layers has an index of refraction different from another layer.

32. The display of claim 27, wherein each interference layer is a dielectric material.

33. The display of claim 27, 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.

34. A light guide, comprising:

a transparent substrate; and

a plurality of material layers disposed on the transparent substrate, wherein at least one of the material layers has an index of refraction greater than the index of refraction of the transparent substrate and wherein at least one of the material layers has an index of refraction less than the index of refraction of the transparent substrate, 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.

35. The light guide of claim 34, wherein the transparent substrate is glass.

36. The light guide of claim 34, wherein the material layers are interference layers.

37. The light guide of claim 34, 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.

38. The light guide of claim 37, wherein the light redirectors are disposed in a film disposed on the substrate.

39. The light guide of claim 38, wherein the light redirectors comprise angled surfaces of the film.

40. The light guide of claim 34, 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.

41. The light guide of claim 34, 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.

42. 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 transmitting light.

43. The display of claim 42, wherein the displaying means comprise a plurality of display elements.

44. The display of claim 42, wherein the reflecting means comprise one or more interference layers.

45. The display of claim 42, wherein the reflecting means comprise one or more dielectric layers.

46. The display of claim 42, wherein the transmitting means is a transparent substrate.

47. The display of claim 46, wherein the transparent substrate is glass.

48. A method of manufacturing a display, comprising:

depositing one or more material layers on a first side of a transparent substrate, wherein at least one of said material layers has an index of refraction less than the index of refraction of the transparent substrate, and wherein the combined one or more material layers are adapted to reflect more than 40% of light incident on the layers from within the substrate at angles greater than 70 degrees relative to normal to the layers; and

forming a plurality of display elements on the material layers.

49. The method of claim 48, wherein depositing the material layers comprises:

depositing a first material layer having an index of refraction greater than the transparent substrate on the first side of the transparent substrate; and

depositing a second material layer having an index of refraction lower than the first material layer on the first material layer.

50. The method of claim 48, wherein depositing the material layers comprises depositing a first material layer having an index of refraction lower than the transparent substrate on the first side of the transparent substrate.

51. The method of claim 50, wherein depositing the material layers further comprises depositing a second material layer having an index of refraction greater than the first material layer on the first material layer.

52. The method of claim 48, wherein the materials are deposited using chemical vapor deposition or physical vapor deposition.

53. The method of claim 48, wherein the display elements are interferometric modulators.

54. The method of claim 48, wherein forming the plurality of display elements comprises a plurality of deposition and etching steps.

55. The method of claim 48, wherein the combined one or more material 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.

56. The method of claim 48, further comprising positioning a plurality of light redirectors adjacent to a second side of the transparent substrate opposite the first side, the light redirectors configured to redirect light incident on the light directors into the display elements.

57. The method of claim 56, wherein the light redirectors are disposed in a film and positioning the light redirectors comprises placing the film on the second side of the transparent substrate.

58. The method of claim 57, wherein placing the film on the second side comprises laminating the film on the second side.

59. A display manufactured according to the method of claim 48.

60. A method of illuminating a display, comprising:

transmitting light into an edge of a transparent substrate such that the light reflects at least once off an optical isolation structure comprising one or more non-gaseous material layers on the substrate; and

redirecting the light to pass through the substrate and optical isolation structure into a display element without the light passing through air.

61. The method of claim 60, wherein transmitting the light comprises positioning a light source on the edge of the substrate.

62. The method of claim 60, wherein redirecting the light comprises positioning a plurality of light redirectors adjacent to the substrate.

63. The method of claim 60, wherein redirecting the light comprises placing a film comprising a plurality of light redirectors on the substrate.