SYSTEMS AND METHODS OF PROVIDING A LIGHT GUIDING LAYER

• US 20080180956A1
• Filed: 01/30/2007
• Published: 07/31/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Xu, Gang, Bita, Ion, Gruhlke, Russell Wayne, Mienko, Mark
• Granted Patent: US 7,777,954 B2
• Time in Patent Office: Days
• US Class Current: 362/331
• 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

Various embodiments of the invention include an interferometric optical modulator comprising a substrate layer and a light direction layer. Such an interferometric modulator may be integrated with a diffuser layer in a display device in a way that physically integrates the diffuser layer into the light direction layer in a way where the diff-user layer does not interact with light propagating within the light direction layer. As a result, most of the light propagating within the light direction layer does not penetrate into the diffuser which would inhibit performance of the display. In some embodiments, the interface between the diffuser layer and the light direction layer has a lower index of refraction than the light direction layer and the transparent substrate so that total internal reflection occurs at the interface.

Claims

1. A reflective display including a plurality of display elements, the reflective display comprising:

a transparent substrate;

a light direction layer disposed on the substrate, the light direction layer configured to direct at least a portion of incident light toward the substrate; and

a diffuser layer physically coupled to and optically distinct from the light direction layer, wherein the light direction layer is between the diffuser and the transparent substrate.

2. The display of claim 1, the light direction layer comprising a plurality of light redirectors.

3. The display of claim 2, wherein said light redirectors are defined by a non-uniform surface of the light direction layer in contact with at least a portion of the diffuser layer.

4. The display of claim 1, wherein the refractive index of the diffuser layer is less than the refractive index of the light direction layer.

5. The display of claim 1, further comprising a light source positioned between planes defined by said substrate and said diffuser layer, wherein said light source provides said incident light.

6. The display of claim 1, wherein said light direction layer has a refractive index range between 1.40 and 1.65.

7. The display of claim 1, wherein said light direction layer has a width of between 175 and 254 microns.

8. The display of claim 1, wherein said light direction layer is composed of materials including Zylar, polymethyl methacrylate, or polycarbonate.

9. The display of claim 1, wherein the diffuser layer is approximately 25 microns thick.

10. The display of claim 1, wherein the diffuser layer comprises a diffusive film disposed on a clear pressure sensitive adhesive layer,

11. The display of claim 1, wherein said diffuser layer is composed of materials including transparent or translucent polymer resin.

12. The display of claim 1, further comprising:

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

a memory device that is configured to communicate with said processor.

13. The display of claim 12, further comprising a driver circuit configured to send at least one signal to the display.

14. The display of claim 13, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

15. The display of claim 12, further comprising an image source module configured to send said image data to said processor.

16. The display of claim 15, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

17. The display of claim 12, further comprising an input device configured to receive input data and to communicate said input data to said processor.

18. A reflective display including a plurality of display elements, the reflective display comprising:

a transparent substrate;

a light direction layer disposed on the substrate, the light direction layer including a plurality of light redirectors configured to direct at least a portion of incident light toward the substrate;

a high reflectance film disposed on the light direction layer; and

a diffuser layer physically coupled to and optically distinct from the reflectance film, wherein the high reflectance film is located between the diffuser layer and the light direction layer.

19. The display of claim 18, wherein said reflectance film has a refractive index range between 1.4 and 1.7.

20. The display of claim 18, wherein said reflectance film has a width of between 200 and 300 nanometers.

21. The display of claim 18, wherein the reflectance film is comprised of silicon dioxide, silicon nitride, di-aluminium tri-oxide, indium tin oxide, or molybdenum chromium.

22. The display of claim 18, wherein the reflectance film is comprised of dielectric films of alternating high and low refractive index materials.

23. The display of claim 22, wherein the high refractive index materials include silicon nitride and the low refractive index materials include silicon oxide.

24. The display of claim 18, the reflectance film having a lower index of refraction tan the light direction layer.

25. A reflective display including a plurality of display elements, the reflective display comprising

a transparent substrate;

a first solid layer with an index of refraction g disposed on the substrate, the layer including a plurality of light redirectors configured to direct at least a portion of incident light toward the substrate; and

a second solid layer with an index of refraction d physically coupled to the first solid layer, wherein d is less than g, and wherein the first solid layer is located between the second solid layer and the transparent substrate.

26. A reflective display including a plurality of display elements, the reflective display comprising:

means for transmitting light onto a surface of a diffuser layer along a path that is oblique to the diffuser layer, the surface of the diffuser layer facing a transparent substrate; and

means for directing at least a portion of said transmitted light towards the transparent substrate.

27. The display of claim 26, wherein said light directing means includes:

absorbing said transmitted light in a fluorescent or phosphorescent material;

and

emitting at least a portion of said absorbed light from said fluorescent or phosphorescent material.

28. The display of claim 27, wherein said light transmitting means includes transmitting light that has a wavelength that is not visible by a human eye.

29. The display of claim 26, wherein said light transmitting means includes providing a light source that transmits light along a path oblique to the cover.

30. A method of illuminating, comprising:

transmitting light onto a surface of a diffuser layer along a pat that is oblique to the diffuser layer, the surface of the diffuser layer facing a transparent substrate; and

directing at least a portion of said transmitted light towards the transparent substrate.

31. The method of claim 30, wherein said directing includes:

absorbing said transmitted light in a fluorescent or phosphorescent material; and

emitting at least a portion of said absorbed light from said fluorescent or phosphorescent material.

32. The method of claim 31, wherein said transmitting includes transmitting light that has a wavelength that is not visible by a human eye.

33. The method of claim 30, wherein said transmitting includes providing a light source that transmits light along a path oblique to the cover.

34. A method of illuminating a display, comprising:

transmitting light onto a high reflectance film along a path that is oblique to the film; and

directing at least a portion of said transmitted light so that directed light is directed along a path that is less oblique to said film than said transmitted light.

35. The method of claim 34, wherein said transmitting includes providing a light source that transmits light along a path oblique to the display panel.

37. The display produced by the process of claim 34, further comprising:

positioning a reflectance film between the diffuser layer and the light direction layer.

38. The display produced by the process of claim 34, wherein the diffuser layer is physically coupled to and optically distinct from the light direction layer, and wherein the light direction layer is located between the diffuser layer and the transparent substrate.

39. The display produced by the process of claim 34, wherein the diffuser layer is positioned on the light direction layer using a pressure sensitive adhesive.

36. A reflective display produced by a process comprising:

positioning a light direction layer on a transparent substrate, the light direction layer comprising a plurality of light redirectors configured to direct at least a portion of incident light toward the substrate;

positioning a diff-user layer on the light direction layer.

40. A microelectromechanical (MIMS) device fabricated by the method of claim 36.