Microelectromechanical device with spacing layer

• US 8,068,269 B2
• Filed: 09/24/2009
• Issued: 11/29/2011
• Est. Priority Date: 03/27/2008
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Djordjev, Kostadin
• Primary Examiner(s): Sugarman; Scott J
• Assistant Examiner(s): Jones; James
• Application Number:
  US12/566,510
• Publication Number:
  US 20100014148A1
• Time in Patent Office: 796 Days
• Field of Search: 592/90, 592/91
• US Class Current: 359/290
• 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 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

An interferometric modulating device is provided with a spacing layer positioned between the fixed reflector and the electrode. The spacing layer prevents shorting between the movable reflector and the electrode and provides a filtering cavity to improve color saturation.

Claims

1. A device comprising:

a substrate;

a fixed reflector;

a movable reflector comprising an electrically conductive material, wherein an interferometric cavity is defined between the movable reflector and the fixed reflector, the movable reflector being movable between at least a first position, a second position, and a third position; and

a spacing layer positioned on a side of the fixed reflector that is opposite from the movable reflector, wherein the spacing layer is positioned between the fixed reflector and the substrate, wherein the spacing layer provides a filtering cavity configured to improve color saturation of light reflected by the interferometric cavity.

2. The device of claim 1, wherein the spacing layer is between the fixed reflector and an electrode.

3. The device of claim 1, wherein the thickness of the spacing layer is at least 160 nm.

4. The device of claim 1, wherein the device reflects red light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 140 nm.

5. The device of claim 1, wherein the device reflects blue light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 210 nm.

6. The device of claim 1, wherein the device reflects green light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 190 nm.

7. The device of claim 1, wherein the device reflects white light when the movable reflector is at the first position and does not reflect light when the movable reflector is at the second position.

8. The device of claim 1, wherein the filtering cavity comprises another interferometric cavity that is defined on the side of the fixed reflector that is opposite from the movable reflector.

9. The device of claim 8, wherein the other interferometric cavity is defined between the fixed reflector and the substrate.

10. The device of claim 1, further comprising:

a display;

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

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

11. The device of claim 10, further comprising a driver circuit configured to send at least one signal to the display.

12. The device of claim 11, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

13. The device of claim 10, further comprising an image source module configured to send the image data to the processor.

14. The device of claim 13, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

15. The device of claim 10, further comprising an input device configured to receive input data and to communicate the input data to the processor.

39. The device of claim 1, wherein the fixed reflector is conductive.

16. A device comprising:

a substrate;

a fixed reflector;

a movable reflector comprising an electrically conductive material, wherein an interferometric cavity is defined between the movable reflector and the fixed reflector, the movable reflector being movable between at least a first position, a second position, and a third position; and

a spacing layer positioned on a side of the fixed reflector that is opposite from the movable reflector, the spacing layer being positioned between the fixed reflector and the substrate, the spacing layer being greater than or equal to 160 nm in thickness from a cross-sectional view of the device, wherein the spacing layer provides a filtering cavity configured to improve color saturation of light reflected by the interferometric cavity.

17. The device of claim 16, wherein the spacing layer is between the fixed reflector and an electrode.

18. The device of claim 16, wherein the filtering cavity comprises another interferometric cavity that is defined on the side of the fixed reflector that is opposite from the movable reflector.

19. The device of claim 18, wherein the other interferometric cavity is defined between the fixed reflector and the substrate.

40. The device of claim 16, wherein the fixed reflector is conductive.

20. A device comprising:

a substrate;

first means for reflecting light, the first reflecting means being fixed;

second means for reflecting light, the second reflecting means being movable and comprising an electrically conductive material, wherein an interferometric cavity is defined between the first reflecting means and the second reflecting means, the second reflecting means being movable between at least a first position, a second position, and a third position; and

means for separating the first reflecting means positioned on a side of the first reflecting means that is opposite from the second reflecting means, wherein the means for separating the first reflecting means is positioned between the first reflecting means and the substrate, wherein the means for separating the first reflecting means provides a filtering cavity configured to improve color saturation of light reflected by the interferometric cavity.

21. The device of claim 20, wherein the means for separating the first reflecting means is between the first reflecting means and an electrode.

22. The device of claim 20, wherein the thickness of the separating means is at least 160 nm.

23. The device of claim 20, wherein the device reflects red light when the second reflecting means is at the third position, and wherein the separating means comprises SiO₂ and a thickness of the separating means is at least 140 nm.

24. The device of claim 20, wherein the device reflects blue light when the second reflecting means is at the third position, and wherein the separating means comprises SiO₂ and a thickness of the separating means is at least 210 nm.

25. The device of claim 20, wherein the device reflects green light when the second reflecting means is at the third position, and wherein the separating means comprises SiO₂ and a thickness of the separating means is at least 190 nm.

26. The device of claim 20, wherein the device reflects white light when the second reflecting means is at the first position and does not reflect light when the second reflecting means is at the second position.

27. The device of claim 20, wherein the filtering cavity comprises another interferometric cavity that is defined on the side of the first reflecting that is opposite from the second reflecting means.

28. The device of claim 27, wherein the other interferometric cavity is defined between the first reflecting means and the substrate.

41. The device of claim 20, wherein the first reflecting means is conductive.

29. A method of making a device for modulating light, the method comprising:

providing a substrate;

forming a spacing layer;

forming a fixed reflector such that the spacing layer is disposed between the substrate and the fixed reflector; and

forming a movable reflector comprising an electrically conductive material;

wherein an interferometric cavity is defined between the movable reflector and the fixed reflector, the movable reflector being movable between at least a first position, a second position, and a third position; and

wherein the spacing layer provides a filtering cavity configured to improve color saturation of light reflected by the interferometric cavity.

30. The method of claim 29, wherein the spacing layer is positioned on a side of the fixed reflector that is opposite from the movable reflector.

31. The method of claim 30, wherein the spacing layer is between the fixed reflector and the substrate.

32. The method of claim 29, wherein the thickness of the spacing layer is at least 160 nm.

33. The method of claim 29, wherein the device reflects red light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 140 nm.

34. The method of claim 29, wherein the device reflects blue light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 210 nm.

35. The method of claim 29, wherein the device reflects green light when the movable reflector is at the third position, and wherein the spacing layer comprises SiO₂ and a thickness of the spacing layer is at least 190 nm.

36. The method of claim 29, wherein the device reflects white light when the movable reflector is at the first position and does not reflect light when the movable reflector is at the second position.

37. The method of claim 29, wherein the filtering cavity comprises another interferometric cavity that is defined on the side of the fixed reflector that is opposite from the moveable reflector.

38. The method of claim 37, wherein the other interferometric cavity is defined between the fixed reflector and the substrate.

42. The method of claim 29, wherein the fixed reflector is conductive.