Display element having filter material diffused in a substrate of the display element

• US 20060067600A1
• Filed: 08/19/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Cummings, William J.
• Granted Patent: US 7,807,488 B2
• Time in Patent Office: Days
• US Class Current: 385/3
• 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

Abstract

Optical filter functionality is incorporated into a substrate of a display element thereby decreasing the need for a separate thin film filter and, accordingly, reducing a total thickness of a filtered display element. Filter functionality may be provided by any filter material, such as pigment materials, photoluminescent materials, and opaque material, for example. The filter material may be incorporated in the substrate at the time of creating the substrate or may be selectively diffused in the substrate through a process of masking the substrate, exposing the substrate to the filter material, and heating the substrate in order to diffuse the filter material in the substrate.

Claims

1. A method of forming a display device, the method comprising:

diffusing a material into a substrate, said material having a different optical property than said substrate; and

forming at least one light modulating element over the substrate, the light modulating element comprising a partially reflective surface and a substantially reflective surface that form an optical cavity, at least one of said reflective surfaces movable with respect to the other to modulate said optical cavity.

2. The method of claim 1, further comprising depositing the material over the substrate.

3. The method of claim 2, further comprising heating the substrate.

4. The method of claim 2, further comprising heating the substrate to a temperature in the range of about 200 to 250 degrees Celsius.

5. The method of claim 3, wherein the substrate is heated for a time sufficient to diffuse the material to a predetermined level within the substrate.

6. The method of claim 5, wherein the predetermined level is less than about ⅓

of a thickness of the substrate.

7. The method of claim 5, wherein the predetermined level is greater than about ⅓

of a thickness of the substrate.

8. The method of claim 1, wherein at least one optical characteristic of the material changes as the material diffuses into the substrate.

9. The method of claim 1, further comprising applying the material to the substrate.

10. The method of claim 9, wherein applying comprises spraying the material.

11. The method of claim 9, further comprising positioning a mask on the substrate prior to applying the material to the substrate.

12. The method of claim 1, wherein the substrate comprises at least one of:

glass and polymer.

13. The method of claim 1, wherein the material comprises black pigment.

14. The method of claim 1, wherein the material comprises colored pigment.

15. The method of claim 1, further comprising diffusing different materials into the substrate.

16. The method of claim 15, wherein different materials are diffused for different light modulating elements.

17. A display device formed by the process of claim 1.

18. A display device comprising:

at least one light modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a substrate, said light modulating element disposed over said substrate,

wherein said substrate comprises a color filter that transmits color light.

19. The display device of claim 18, wherein the substrate comprises a plurality of color filters that transmit different color light when illuminated by white light.

20. The display device of claim 19, wherein the color filters have different colors for different of said light modulating elements.

21. The display of claim 19 wherein said plurality of color filters include red, green, and blue color filters that transmits red, green, or blue light, respectively, when illuminated by white light.

22. The display device of claim 18, wherein said color filter comprises a magenta color filter that transmits magenta light when illuminated with white light.

23. The display device of claim 18, wherein said color filter comprises pigment.

24. The display device of claim 18, wherein the color filter is substantially optically transmissive to visible light in a first wavelength region and substantially absorptive to visible light in a second wavelength region.

25. The display device of claim 24, wherein the first wavelength region includes red wavelengths and said second wavelength regions includes other wavelengths such that said color filter is substantially optically transmissive to red light when illuminated with white light.

26. The display device of claim 24, wherein the first wavelength region includes green wavelengths and said second wavelength regions includes other wavelengths such that said color filter is substantially optically transmissive to green light when illuminated with white light.

27. The display device of claim 24, wherein the first wavelength region includes blue wavelengths and said second wavelength regions includes other wavelengths such that said color filter is substantially optically transmissive to blue light when illuminated with white light.

28. The display device of claim 24, wherein the light modulating element is configured to reflect light in said first wavelength region.

29. The display device of claim 18, wherein the light modulating element is configured to reflect second order red and third order blue and the color filter is substantially optically transmissive to second order red and absorbs third order blue.

30. The display device of claim 18, wherein the light modulating element is configured to substantially reflect green light and the color filter is substantially optically transmissive to magenta light when illuminated with visible light.

31. The display device of claim 18, wherein the color filter comprises one or more pigments.

32. The display device of claim 18, wherein the color filter comprises one or more photoluminescent materials.

33. The display device of claim 18, wherein as an angle between a direction of light reflected normal to a surface of the substrate increases, filtering performed by the color filter increases.

34. The display device of claim 18, further comprising one or more supports for supporting one of said reflective surfaces.

35. The display device of claim 18, wherein the color filter is patterned on the substrate so that the color filter is substantially forward of the one or more supports.

36. The display device of claim 18, further comprising:

a processor that is in electrical communication with said at least one light modulating element, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

37. The display device of claim 36, further comprising:

a driver circuit configured to send at least one signal to at least one light modulating element.

38. The display device of claim 37, further comprising:

a controller configured to send at least a portion of said image data to said driver circuit.

39. The display device of claim 36, further comprising:

an image source module configured to send said image data to said processor.

40. The display device of claim 39, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

41. The display device of claim 36, further comprising:

an input device configured to receive input data and to communicate said input data to said processor.

42. A display device comprising:

at least one light-modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a substrate, said light-modulating element disposed over said substrate,

wherein said substrate incorporates at least tinting.

43. The display device of claim 42, wherein said tinting is configured to absorb substantially all wavelengths of visible light and the tinting is disposed forward of a support for said first reflective surface.

44. The display device of claim 43, wherein said support comprises a post structure.

45. A display device comprising:

a plurality of light-modulating elements each comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a substrate, said plurality of light-modulating elements disposed over said substrate,

wherein said substrate includes therein first and second absorptive regions, said first and second absorptive regions having different optical transmission properties.

46. The display device of claim 45, wherein said first regions comprise color filters that transmit a color when illuminated by white light.

47. The display device of claim 45, wherein said first regions are below said light modulating elements and said second regions are below areas between said light-modulating elements.

48. The display device of claim 45, wherein said first regions comprise color filters having different colors for different of said light modulating elements.

49. The display device of claim 45, wherein said first regions comprise masks.

50. The display device of claim 45, wherein said first regions are below supports for said first reflective surfaces and said second regions are below areas between said supports.

51. The display device of claim 45, wherein said first regions comprise material diffused into said substrate.

52. The display device of claim 51, wherein said second regions are substantially devoid of said material diffused in said first regions.

53. The display device of claim 45, wherein said first regions comprise pigmented regions.

54. A display device comprising:

at least one plurality of light modulating elements each comprising first and second reflective surfaces, said second surfaces being movable with respect to said first surfaces; and

a substrate, said at least one plurality of light modulating elements disposed over said substrate,

wherein said substrate comprises a plurality of elements configured to limit a field-of-view of the display device.

55. The display of claim 54, wherein the plurality of elements configured to limit a field-of-view of the display comprises a plurality of baffles.

56. The display of claim 55, wherein the substrate is in a horizontal plane and the plurality of baffles comprise substantially planar surfaces substantially parallel to a vertical plane.

57. The display of claim 55, wherein the plurality of baffles comprise spacings between individual baffles, said spacing having a dimension that provides a view angle of not more than about 40 degrees from a plane normal to said substrate, wherein the angle is measured as a half-angle with respect to the normal plane.

58. The display of claim 55, wherein the plurality of baffles comprise spacings between individual baffles, said spacing having a dimension that provides a view angle of not more than about 20 degrees from a plane normal to the substrate, wherein the angle is measured as a half-angle with respect to the normal plane.

59. The display of claim 55, wherein the plurality of baffles are substantially opaque.

60. The display of claim 59, wherein the plurality of baffles comprise substantially planar opaque surfaces.

61. The display of claim 55, wherein the plurality of baffles comprises absorbing material.

62. The display of claim 55, wherein the plurality of baffles comprises a reflecting material.

63. A method of forming an interferometric modulator, the method comprising:

combining a substrate material with a filter material in order to form a mixture;

heating the mixture so that the substrate material substantially melts and the filter material is diffused within the melted substrate material;

cooling the mixture in order to form a substrate; and

forming at least one light modulating element over the substrate, the light modulating element comprising a partially reflective surface and a substantially reflective surface that form an optical cavity, at least one of said reflective surfaces movable with respect to the other to modulate said optical cavity.

64. The method of claim 63, wherein the raw substrate material comprises at least one of:

polymer pellets, sand, flint, or quartz.

65. The method of claim 63, wherein the substrate material is at least partially molten when combined with the filter material.

66. The method of claim 63, wherein the substrate material is not molten when combined with the filter material.

67. A display device comprising:

means for modulating light; and

means for supporting said light modulating means; and

means for filtering light disposed in said supporting means.

68. The apparatus of claim 67, wherein said modulating means comprises first and second reflective surfaces, said second reflective surfaces being movable with respect to said first reflective surface.

69. The apparatus of claim 68, wherein said supporting means comprises a substrate.

70. The apparatus of claim 69, wherein said filtering means comprises a color filter, photoluminescent material, or a mask.

71. A display device comprising:

means for modulating light; and

means for supporting said light modulating means; and

means for limiting a field-of-view.

72. The apparatus of claim 71, wherein said modulating means comprises first and second reflective surfaces, said second reflective surfaces being movable with respect to said first reflective surface.

73. The apparatus of claim 72, wherein said supporting means comprises a substrate.

74. The apparatus of claim 73, wherein said field-of-view limiting means comprises baffles.

75. A display device comprising:

at least one light-modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a substrate, said light-modulating element disposed over said substrate,

wherein said substrate incorporates at least one photoluminescent material.

76. The display device of claim 75, wherein the at least one photoluminescent material comprises at least one of:

phosphorescent and fluorescent materials.

77. The display device of claim 75, wherein the at least one photoluminescent material illuminates the light modulating element when excited by a light source.

78. The display device of claim 75, wherein illumination from the photoluminescent material comprises light having a wavelength larger than a wavelength of the light source.