Method and post structures for interferometric modulation

• US 7,719,747 B2
• Filed: 02/25/2008
• Issued: 05/18/2010
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sethuraman, Srinivasan, Tung, Ming-Hau
• Primary Examiner(s): Ben; Loha
• Application Number:
  US12/036,958
• Publication Number:
  US 20080180777A1
• Time in Patent Office: 813 Days
• Field of Search: 359/214, 359/260, 359/290, 359/291, 359/295, 359/292, 359/298, 359/224, 359/245, 359/247, 359/248, 359/237, 359/238, 359/365, 438/48, 438/222, 438/478, 385/129, 385/147, 356/445, 356/477, 356/503, 356/504, 216/13, 216/17, 345/85, 257/416, 427/123
• 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

Abstract

An interferometric modulator includes a post structure comprising an optical element. In a preferred embodiment, the optical element in the post structure is a reflective element, e.g., a mirror. In another embodiment, the optical element in the post structure is an etalon, e.g., a dark etalon. The optical element in the post structure may decrease the amount of light that would otherwise be retroreflected from the post structure. In various embodiments, the optical element in the post structure increases the brightness of the interferometric modulator by redirecting light into the interferometric cavity. For example, in certain embodiments, the optical element in the post structure increases the backlighting of the interferometric modulator.

Claims

1. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element,

wherein the optical element is disposed at a height between the first reflective surface and the second reflective surface.

2. The interferometric modulator of claim 1, wherein surfaces of the optical element are symmetrical.

3. The interferometric modulator of claim 1, wherein surfaces of the optical element are smooth.

4. The interferometric modulator of claim 1, wherein the optical element comprises a reflector having an inclined surface.

5. The interferometric modulator of claim 1, wherein the optical element comprises a reflector having declined surface.

6. The interferometric modulator of claim 1, wherein the optical element comprises a reflector having a flat surface.

7. The interferometric modulator of claim 1, wherein the optical element comprises an etalon.

8. The interferometric modulator of claim 1, wherein the optical element comprises a lens.

9. The interferometric modulator of claim 1, wherein the optical element comprises a prism.

10. The interferometric modulator of claim 1, wherein the optical element comprises a reflector.

11. The interferometric modulator of claim 1, wherein the optical element comprises a specular reflector.

12. The interferometric modulator of claim 1, wherein the optical element comprises a diffuse reflector.

13. The interferometric modulator of claim 1, wherein the interferometric modulator comprises a reflective modulator.

14. The interferometric modulator of claim 1, wherein the interferometric modulator comprises a MEMS interferometric modulator.

15. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element,

wherein the optical element comprises a lens or a prism.

16. The interferometric modulator of claim 15, wherein the optical element comprises a lens.

17. The interferometric modulator of claim 16, wherein at least one surface of the lens is convex.

18. The interferometric modulator of claim 15, wherein the optical element comprises a prism.

19. The interferometric modulator of claim 18, wherein surfaces of the prism are inclined with respect to the support structure.

20. The interferometric modulator of claim 18, wherein surfaces of the prism are declined with respect to the support structure.

21. The interferometric modulator of claim 15, wherein the interferometric modulator comprises a reflective modulator.

22. The interferometric modulator of claim 15, wherein the interferometric modulator comprises a MEMS interferometric modulator.

23. The interferometric modulator of claim 16, wherein at least one surface of the lens is concave.

24. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein surfaces of the optical element are asymmetrical.

25. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein surfaces of the optical element are rough.

26. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein the optical element is configured to specularly reflect light.

27. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein the optical element is configured to diffusely reflect light.

28. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein the optical element is disposed off-center from the support pest-structure.

29. An interferometric modulator array comprising:

a first reflective surface over a substrate;

a plurality of second reflective surfaces over the first reflective surface, each of the second reflective surfaces movable with respect to the first reflective surface; and

a plurality of support structures each configured to at least partially support the second reflective surfaces, wherein at least some of the plurality of support structures comprise an optical element,

wherein the optical element is disposed at a height between the first reflective surface and at least one of the plurality of second reflective surfaces.

30. The interferometric modulator of claim 29, wherein the optical element comprises a lens.

31. The interferometric modulator of claim 29, wherein the optical element comprises a prism.

32. The interferometric modulator of claim 29, wherein the optical element comprises a reflector.

33. The interferometric modulator of claim 29, wherein the optical element comprises an etalon.

34. An interferometric modulator array comprising:

a first reflective surface over a substrate;

a plurality of second reflective surfaces over the first reflective surface, each of the second reflective surfaces movable with respect to the first reflective surface; and

a plurality of support structures configured to at least partially support the second reflective surfaces, wherein at least some of the plurality of support structures each comprise an optical element, wherein some of the optical elements are different from others of the optical elements.

35. The interferometric modulator array of claim 34, wherein heights of the some of the optical elements are different from heights of the other of the optical elements.

36. An interferometric modulator array comprising:

a first reflective surface over a substrate;

a plurality of second reflective surfaces over the first reflective surface, each of the second reflective surfaces movable with respect to the first reflective surface; and

a plurality of support structures configured to at least partially support the second reflective surfaces, wherein at least some of the plurality of support structures each comprise an optical element,

wherein some of the optical elements comprise an etalon.

37. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein the optical element comprises a light diffracting element, a scattering element, a total internal reflecting element, or a refractive element.

38. The interferometric modulator of claim 37, wherein the optical element comprises a light diffracting element.

39. The interferometric modulator of claim 37, wherein the optical element comprises a scattering element.

40. The interferometric modulator of claim 37, wherein the optical element comprises a total internal reflecting element.

41. The interferometric modulator of claim 37, wherein the optical element comprises a refractive element.

42. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element, wherein the optical element is disposed above the first reflective surface.

43. The interferometric modulator of claim 42, wherein the interferometric modulator comprises a reflective modulator.

44. The interferometric modulator of claim 42, wherein the interferometric modulator comprises a MEMS interferometric modulator.

45. An interferometric modulator comprising:

a substrate;

a first reflective surface over the substrate, the first reflective surface being at least partially reflective and at least partially transparent to light;

a second reflective surface over the first reflective surface, the second reflective surface movable with respect to the first reflective surface; and

a support structure configured to at least partially support the second reflective surface, the support structure comprising an optical element,

wherein the optical element comprises an etalon.