Microelectromechanical device with spacing layer

• US 7,612,933 B2
• Filed: 03/27/2008
• Issued: 11/03/2009
• 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): Schwartz; Jordan M.
• Assistant Examiner(s): JONES, JAMES
• Application Number:
  US12/057,161
• Publication Number:
  US 20090244686A1
• Time in Patent Office: 586 Days
• Field of Search: 359/290, 359/291
• 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:

an electrode;

a fixed reflector;

a movable reflector comprising an electrically conductive material, wherein an interferometric modulating 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 between the fixed reflector and the electrode, wherein the spacing layer comprises a filtering cavity configured to improve color saturation of the interferometric modulating cavity.

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

3. 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.

4. 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.

5. 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.

6. 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.

7. The device of claim 1, wherein the filtering cavity comprises another interferometric modulation cavity that is defined between the fixed reflector and the electrode.

8. 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.

9. The device of claim 8, further comprising a driver circuit configured to send at least one signal to the display.

10. The device of claim 9, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

11. The device of claim 8, further comprising an image source module configured to send the image data to the processor.

12. The device of claim 11, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

13. The device of claim 8, further comprising an input device configured to receive input data and to communicate the input data to the processor.

14. A device comprising:

an electrode;

a fixed reflector;

a movable reflector comprising an electrically conductive material, wherein an interferometric modulating 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 between the fixed reflector and the electrode, the spacing laying being greater than or equal to 160 nm in thickness from a cross-sectional view of the device, wherein the spacing layer comprises a filtering cavity configured to improve color saturation of the interferometric modulating cavity.

15. The device of claim 14, wherein the spacing layer filtering cavity comprises another interferometric modulating cavity that is defined between the fixed reflector and the electrode.

16. A device comprising:

an electrode;

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 modulating 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 and the electrode, wherein the means for separating the first reflecting means and the electrode comprises a filtering cavity configured to improve color saturation of the interferometric modulating cavity.

17. The device of claim 16, wherein the thickness of the separating means is at least 160 nm.

18. The device of claim 16, 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.

19. The device of claim 16, 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.

20. The device of claim 16, 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.

21. The device of claim 16, 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.

22. The device of claim 16, wherein the filtering cavity comprises another interferometric modulating cavity that is defined between the first reflecting means and the electrode.

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

forming an electrode;

forming a spacing layer;

forming a fixed reflector; and

forming a movable reflector comprising an electrically conductive material;

wherein an interferometric modulating 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 comprises a filtering cavity configured to improve color saturation of the interferometric modulating cavity.

24. The method of claim 23, wherein the thickness of the spacing layer is at least 160 nm.

25. The method of claim 23, 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.

26. The method of claim 23, 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.

27. The method of claim 23, 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.

28. The method of claim 23, 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.

29. The method of claim 23, wherein the filtering cavity comprises another interferometric modulating cavity that is defined between the fixed reflector and the electrode.