Spatial light modulator with integrated optical compensation structure

• US 8,045,252 B2
• Filed: 02/20/2008
• Issued: 10/25/2011
• Est. Priority Date: 02/03/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence, Sampsell, Jeffrey B., Cummings, William J., Tung, Ming-Hau
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US12/034,499
• Publication Number:
  US 20080151347A1
• Time in Patent Office: 1,343 Days
• Field of Search: 359/238, 359290-292, 359/237, 359/298, 359/308
• US Class Current: 359/238
• 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: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors
• CPC Class Codes: G02F 1/13356 characterised by the placement of the optical elements
• CPC Class Codes: G02F 1/21 by interference

Abstract

A spatial light modulator comprises an integrated optical compensation structure, e.g., an optical compensation structure arranged between a substrate and a plurality of individually addressable light-modulating elements, or an optical compensation structure located on the opposite side of the light-modulating elements from the substrate. The individually addressable light-modulating elements are configured to modulate light transmitted through or reflected from the transparent substrate. Methods for making such spatial light modulators involve fabricating an optical compensation structure over a substrate and fabricating a plurality of individually addressable light-modulating elements over the optical compensation structure. The optical compensation structure may be a passive optical compensation structure. The optical compensation structure may include one or more of a supplemental frontlighting source, a diffuser, a black mask, a diffractive optical element, a color filter, an anti-reflective layer, a structure that scatters light, a microlens array, and a holographic film.

Claims

1. A spatial light modulator comprising:

a substrate;

a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;

a first optical compensation structure under the substrate;

a second optical compensation structure between the substrate and the light-modulating elements, at least a portion of the second optical compensation structure, facing the plurality of light-modulating elements, being non-planar; and

a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer contacting the non-planar portion of the second optical compensation structure.

2. The spatial light modulator of claim 1, wherein the substrate is transparent to light.

3. The spatial light modulator of claim 1, wherein the first optical compensation structure comprises a diffuser.

4. The spatial light modulator of claim 1, wherein the second optical compensation structure comprises a plurality of scattering elements.

5. The spatial light modulator of claim 1, wherein the second optical compensation structure comprises a microlens array.

6. The spatial light modulator of claim 1, wherein the second optical compensation structure comprises a diffractive optical element.

7. The spatial light modulator of claim 1, wherein the second optical compensation structure comprises a scattering element.

8. The spatial light modulator of claim 1, wherein the first optical compensation structure is a passive optical compensation structure.

9. The spatial light modulator of claim 1, wherein the second optical compensation structure is a passive optical compensation structure.

10. The spatial light modulator of claim 1, wherein the second optical compensation structure comprises one or more of the group consisting of a plurality of scattering elements, a microlens array, a diffuser, a black mask, and a diffractive optical element.

11. The spatial light modulator of claim 10, wherein the first optical compensation structure comprises one or more of the group consisting of a diffuser, a color filter, a black mask, a plurality of scattering elements, a microlens array, a holographic film, and a diffractive optical element.

12. The spatial light modulator of claim 1, wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.

13. The spatial light modulator of claim 1, wherein the first optical compensation structure is configured to have a different optical effect than the second optical compensation structure.

14. The spatial light modulator of claim 1, wherein the first optical compensation structure is substantially non-planar.

15. The spatial light modulator of claim 1, wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.

16. The spatial light modulator of claim 1, wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.

17. The spatial light modulator of claim 1, wherein the planarization layer forms a support layer for subsequent fabrication steps.

18. The spatial light modulator of claim 1, wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.

19. A spatial light modulator comprising:

a substrate;

a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;

a first optical compensation structure under the substrate;

a second optical compensation structure having a non-planar portion and arranged between the substrate and the light-modulating elements, wherein the second optical compensation structure comprises one or more of the group consisting of a plurality of scattering elements, a microlens array, a diffuser, and a diffractive optical element; and

a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer in contact with the non-planar portion of the second optical compensation structure.

20. The spatial light modulator of claim 19, wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.

21. The spatial light modulator of claim 19, wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.

22. The spatial light modulator of claim 19, wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.

23. The spatial light modulator of claim 19, wherein the planarization layer forms a support layer for subsequent fabrication steps.

24. The spatial light modulator of claim 19, wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.

25. The spatial light modulator of claim 19, wherein the second optical compensation structure comprises a plurality of scattering elements.

26. The spatial light modulator of claim 19, wherein the second optical compensation structure comprises a microlens array.

27. The spatial light modulator of claim 19, wherein the second optical compensation structure comprises a diffuser.

28. The spatial light modulator of claim 19, wherein the second optical compensation structure comprises a diffractive optical element.

29. A spatial light modulator comprising:

a substrate;

a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;

a first optical compensation structure under the substrate;

a second optical compensation structure arranged between the substrate and the light-modulating elements, wherein the first optical compensation structure is configured to achieve a different optical effect than the second optical compensation structure; and

a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer in contact with a non-planar portion of the second optical compensation structure.

30. The spatial light modulator of claim 29, wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.

31. The spatial light modulator of claim 29, wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.

32. The spatial light modulator of claim 29, wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.

33. The spatial light modulator of claim 29, wherein the planarization layer forms a support layer for subsequent fabrication steps.

34. The spatial light modulator of claim 29, wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.