System and method of illuminating interferometric modulators using backlighting

• US 20060077510A1
• Filed: 02/11/2005
• Published: 04/13/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Chui, Clarence, Tung, Ming-Hau
• Granted Patent: US 7,355,780 B2
• Time in Patent Office: Days
• US Class Current: 359/260
• 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: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04W 52/027 by controlling a display operation or backlight unit
• CPC Class Codes: Y02D 30/70 in wireless communication networks
• CPC Class Codes: Y10S 359/90 Methods

Abstract

An interferometric modulator array device with backlighting is disclosed. The interferometric modulator array device comprises a plurality of interferometric modulator elements, wherein each of the interferometric modulator elements comprises an optical cavity. The interferometric modulator array includes an optical aperture region, and at least one reflecting element is positioned so as to receive light passing through the optical aperture region and reflect at least a portion of the received light to the cavities of the interferometric modulator elements. In some embodiments, the interferometric modulator elements may be separated from each other such that an optical aperture region is formed between adjacent interferometric modulator elements.

Claims

1. A spatial light modulator, comprising:

a light-modulating array comprising a plurality of light-modulating elements each having a cavity defined by first and second optical surfaces, said second optical surface movable with respect to the first optical surface;

at least one optical aperture region in said light-modulating array; and

at least one reflecting element formed between a substrate and the plurality of light-modulating elements and configured to receive light passing through the optical aperture region and to reflect at least a portion of the received light to said cavity.

2. The spatial light modulator of claim 1, wherein the at least one optical aperture region is positioned at a substantially central location in the light-modulating array.

3. The spatial light modulator of claim 1, wherein the at least one reflecting element comprises at least one of aluminum, silver, titanium, gold, and copper.

4. The spatial light modulator of claim 1, wherein the at least one reflecting element has a sloped surface.

5. The spatial light modulator of claim 1, wherein the at least one reflecting element has a substantially convex geometry.

6. The spatial light modulator of claim 1, wherein the at least one reflecting element has a substantially concave geometry.

7. The spatial light modulator of claim 1, further comprising a mask aligned with the at least one reflecting element so as to at least partially obstruct a view of the at least one reflecting element.

8. The spatial light modulator of claim 7, wherein the mask comprises at least a portion of an etalon.

9. The spatial light modulator of claim 8, wherein the portion of the etalon comprises one or more layers of partially reflective, partially transmissive material and one or more spacing layers.

10. The spatial light modulator of claim 1, wherein the at least one reflecting element comprises at least a shaped feature and a reflecting material over the shaped feature.

11. The spatial light modulator of claim 1, wherein the substrate of the light-modulating array comprises at least one cavity, and wherein the at least one reflecting element is formed in the cavity of the substrate.

12. The spatial light modulator of claim 1, wherein the at least one reflecting element comprises sections interconnected so as to form a continuous unitary structure extending proximal to a plurality of light-modulating elements.

13. The spatial light modulator of claim 1, wherein the plurality of light-modulating elements comprise a metal layer, and wherein the metal layer has a plurality of optically transmissive apertures.

14. The spatial light modulator of claim 1, wherein at least some of said light-modulating elements are separated from each other so as to form an optical aperture region therebetween.

15. The spatial light modulator of claim 1, wherein the at least one reflecting element comprises a reflective material in substantially particulate form suspended in a substantially transparent material.

16. A method of manufacturing a spatial light modulator, comprising:

forming at least one reflecting element on a substrate; and

forming a plurality of light-modulating elements on the substrate above the at least one reflecting element so as to form an light-modulating array, the light modulating array having at least one optically transmissive aperture region, each light modulating element comprising first and second optical surfaces that define an cavity, said second optical surface movable with respect to the first optical surface,

wherein the at least one reflecting element is configured to receive light through the at least one aperture region and reflect at least a portion of the received light into said cavity.

17. The method of claim 16, wherein forming the at least one reflecting element comprises depositing at least one of aluminum, silver, titanium, gold, and copper.

18. The method of claim 16, wherein forming the at least one reflecting element comprises forming a substantially sloped surface.

19. The method of claim 16, wherein forming the at least one reflecting element comprises forming a substantially convex geometry.

20. The method of claim 16, wherein forming the at least one reflecting element comprises forming a substantially concave geometry.

21. The method of claim 16, wherein said at least one reflecting element is formed on a layer of material formed on said substrate.

22. The method of claim 16, further comprising forming a concealing feature on the substrate aligned with the at least one reflecting element so as to conceal the visible presence of the at least one reflecting element.

23. The method of claim 22, wherein the concealing feature comprises a mask of at least one of absorbing material and a reflective material.

24. The method of claim 22, wherein the concealing feature comprises a mask layer of at least one of carbon black material, a dye, chromium, and molybdenum.

25. The method of claim 22, wherein the concealing feature comprises a metal film so as to form an etalon comprising the metal film and the at least one reflecting element.

26. The method of claim 25, wherein the etalon has a thickness that causes etalon to reflect a color.

27. The method of claim 16, wherein forming the at least one reflecting element comprises forming a shaped base structure on the substrate, and depositing a reflecting material on the shaped base structure.

28. The method of claim 16, further comprising forming a cavity in the substrate, and forming the at least one reflecting element substantially in the cavity of the substrate.

29. The method of claim 16, wherein forming the at least one reflecting element comprises depositing a layer of reflecting material on the substrate and surface treating said layer.

30. The method of claim 16, wherein forming the at least one reflecting element comprises depositing a composite material on the substrate surface, wherein the composite material comprises reflective particles suspended in a substantially transparent material.

31. The method of claim 30, wherein the composite material is deposited at discrete locations on the substrate surface so as to form a plurality of reflecting elements.

32. A spatial light modulator fabricated by the method of claim 16.

33. A method of backlighting an interferometric modulator array, comprising:

positioning a light source proximate a first side of the interferometric modulator array; and

reflecting light from the light source to a second opposite side of the interferometric modulator array with one or more reflecting elements positioned between a substrate and a plurality of interferometric modulator elements formed on the substrate.

34. The method of claim 33, wherein the light is reflected with a plurality of discrete reflecting elements.

35. The method of claim 33, wherein the light is reflected with one or more reflecting elements having sloped surfaces.

36. The method of claim 33, wherein the light is reflected with one or more convex reflecting elements.

37. The method of claim 33, wherein the light is reflected with one or more concave reflecting elements.

38. The method of claim 33, wherein the light is reflected with one or more reflecting elements comprising at least one of aluminum, silver, titanium, gold, and copper.

39. The method of claim 33, wherein the light is reflected with one or more reflecting elements, and wherein the method further comprises masking the one or more reflecting elements to hide the reflecting element from view.

40. The method of claim 39, wherein masking comprises forming at least a portion of an etalon between the one or more reflecting elements and a viewer.