METHOD AND DEVICE FOR MULTISTATE INTERFEROMETRIC LIGHT MODULATION

• US 20110044496A1
• Filed: 11/05/2010
• Published: 02/24/2011
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Cummings, William J., Chui, Clarence
• Granted Patent: US 8,213,075 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• 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: Y10T 29/49002 Electrical device making

Abstract

A multi-state light modulator comprises a first reflector. A first electrode is positioned at a distance from the first reflector. A second reflector is positioned between the first reflector and the first electrode. The second reflector is movable between an undriven position, a first driven position, and a second driven position, each having a corresponding distance from the first reflector. In one embodiment, the three positions correspond to reflecting white light, being non-reflective, and reflecting a selected color of light. Another embodiment is a method of making the light modulator. Another embodiment is a display including the light modulator.

Claims

1. A method of driving an electromechanical system comprising a first electrode, a second electrode, and a movable electrode positioned between the first electrode and the second electrode and configured to move to at least two positions therebetween, the method comprising:

applying a first voltage potential difference between the first electrode and the movable electrode so as to drive the movable electrode to a first position that is closer to the first electrode than the second electrode; and

applying a second voltage potential difference between the second electrode and the movable electrode so as to drive the movable electrode to a second position that is between the second electrode and the first position.

2. The method of claim 1, wherein the second position is closer to the second electrode than the first electrode.

3. The method of claim 1, wherein the second position is closer to the first electrode than the second electrode.

4. The method of claim 1, wherein a first color is output when the movable electrode is in the first position.

5. The method of claim 4, wherein a second color is output when the movable electrode is in the second position.

6. The method of claim 4, wherein incident visible light is substantially absorbed when the movable electrode is in the second position.

7. The method of claim 1, wherein light of a first wavelength is reflected from the electromechanical system when the movable electrode is in the first position.

8. The method of claim 7, wherein light of a second wavelength is reflected from the electromechanical system when the movable electrode is in the second position.

9. The method of claim 7, wherein incident light of visible wavelengths is substantially absorbed when the movable electrode is in the second position.

10. The method of claim 1, further comprising applying a third voltage potential difference between the second electrode and the movable electrode so as to drive the movable electrode to a third position that is between the second position and the second electrode.

11. The method of claim 10, wherein a first color is output when the movable electrode is in the first position.

12. The method of claim 11, wherein incident visible light is substantially absorbed when the movable electrode is in the second position.

13. The method of claim 12, wherein a second color is output when the movable electrode is in the third position.

14. An electromechanical system comprising:

a first electrode;

a second electrode; and

a movable electrode disposed between the first electrode and the second electrode, the movable electrode being configured to move between at least a first position that is disposed closer to the first electrode than the second electrode and a second position that is disposed between the first position and the second electrode,

wherein applying a first voltage potential difference between the first electrode and the movable electrode drives the movable electrode toward the first position and wherein applying a second voltage potential difference between the second electrode and the movable electrode drives the movable electrode toward the second position.

15. The system of claim 14, wherein the first position comprises a position in contact with a dielectric layer.

16. The system of claim 14, wherein the second position comprises a position in contact with a dielectric layer.

17. The system of claim 14, wherein the second position is closer to the second electrode than the first electrode.

18. The system of claim 14, wherein the second position is closer to the first electrode than the second electrode.

19. The system of claim 14, wherein the first electrode is at least partially transparent.

20. The system of claim 19, wherein the first electrode comprises at least one layer of reflective material.

21. The system of claim 14, wherein the movable electrode comprises at least one layer of reflective material.

22. The system of claim 14, wherein the system reflects white light when the movable electrode is in the first position.

23. The system of claim 22, wherein the system reflects light in a range of visible wavelengths associated with a color when the movable electrode is in the second position.

24. The system of claim 22, wherein the system substantially absorbs incident visible light when the movable electrode is in the second position.

25. The system of claim 14, further comprising:

a processor that is configured to communicate with said electrode, said processor being configured to process image data; and

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

26. The system of claim 25, further comprising a driver circuit configured to send at least one signal to the electrode.

27. The system of claim 26, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

28. The system of claim 25, further comprising an image source module configured to send said image data to said processor.

29. The system of claim 28, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

30. The system of claim 25, further comprising an input device configured to receive input data and to communicate said input data to said processor.

31. A method of fabricating an electromechanical 14, the method comprising:

forming a first electrode;

forming a second electrode disposed at a distance from the first electrode; and

forming a movable electrode disposed between the first electrode and the second electrode, the movable electrode being movable between at least a first position that is disposed closer to the first electrode than the second electrode and a second position that is disposed between the first position and the second electrode,

wherein the first electrode, second electrode, and movable electrode are formed such that applying a first voltage potential difference between the first electrode and the movable electrode drives the movable electrode toward the first position and such that applying a second voltage potential difference between the second electrode and the movable electrode drives the movable electrode toward the second position.

32. The method of claim 31, wherein forming the first reflector comprises forming a layer of conductive material.

33. The method of claim 32, wherein the layer of conductive material is at least partially transparent.

34. The method of claim 31, wherein forming the movable reflector comprises forming a layer of conductive material.