Method and device for multistate interferometric light modulation

• US 8,144,385 B2
• Filed: 01/11/2010
• Issued: 03/27/2012
• 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: Chui, Clarence
• Primary Examiner(s): Pinkney, DaWayne
• Application Number:
  US12/685,646
• Publication Number:
  US 20100110526A1
• Time in Patent Office: 806 Days
• Field of Search: 359223-225, 359/198, 359290-292, 359/245, 359260-263, 359/298, 359/295, 359301-303, 359317-318
• US Class Current: 359/295
• 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 2300/04 Structural and physical details of display devices
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A multi-state light modulator comprises a first reflector 104. A first electrode 142 is positioned at a distance from the first reflector 104. A second reflector 14 is positioned between the first reflector 104 and the first electrode 142. The second reflector 14 is movable between an undriven position, a first driven position, and a second driven position, each having a corresponding distance from the first reflector 104. In one embodiment, the light modulator has latch electrodes 17 and 143, which hold the light modulator in a driven state. In another embodiment the latch electrodes 17 and 143 are used to alter the actuation and release thresholds of the light modulator.

Claims

1. A light modulator, comprising:

a movable reflector comprising an electrically conductive material, the movable reflector positioned between at least a first electrode and at least a second electrode, the movable reflector being movable between an undriven position, a first driven position, and a second driven position, wherein the first driven position is closer to the first electrode than are the undriven position and the second driven position; and

at least a third electrode configured to drive the movable reflector to the second driven position;

wherein the first electrode is configured to drive the movable reflector to the first driven position;

wherein the second electrode is configured to modify a release threshold of the movable reflector; and

wherein the first driven position corresponds to a position of the moveable reflector in a first plane, wherein the second driven position corresponds to a position of the moveable reflector in a second plane, wherein the first plane is substantially parallel to the second plane, and wherein the first plane is in a different plane than the second plane.

2. The modulator of claim 1, wherein the modulator substantially absorbs incident visible light when the movable reflector is in the undriven position.

3. The modulator of claim 1, wherein the modulator reflects white light when the movable reflector is in the first driven position.

4. The modulator of claim 1, wherein the modulator selectively reflects light in a range of visible wavelengths associated with a color when the movable reflector is in the second driven position.

5. The modulator of claim 1, further comprising:

a processor that is in electrical communication with at least one of the first and second electrodes, the processor being configured to process image data; and

a memory device in electrical communication with the processor.

6. The modulator of claim 5, further comprising a driver circuit configured to send at least one signal to at least one of the first and second electrodes.

7. The modulator of claim 6, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

8. The modulator of claim 5, further comprising an image source module configured to send the image data to the processor.

9. The modulator of claim 8, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

10. The modulator of claim 5, further comprising an input device configured to receive input data and to communicate the input data to the processor.

11. The modulator of claim 1 wherein the at least the second electrode comprises two electrodes.

12. The light modulator of claim 1, wherein the third electrode is configured to drive the movable reflector to the second driven position through application of a voltage of about 5-15 volts.

13. The light modulator of claim 1, wherein the first electrode is configured to drive the movable reflector to the first driven position through application of a voltage of about 5-15 volts.

14. The light modulator of claim 1, wherein the second electrode is configured to modify the release threshold of the movable reflector through application of a voltage of about 1-10 volts.

15. A method of driving a MEMS device comprising at least a first electrode and at least a second electrode, and a movable electrode positioned between the first electrode and the second electrode and configured to move to at least three 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 driven position;

applying a second voltage potential difference between the second electrode and the movable electrode so as to modify a release threshold of the movable electrode; and

applying a third voltage potential difference between at least a third electrode and the movable electrode so as to drive the movable electrode to a second driven position,

wherein the first driven position corresponds to a position of the reflecting means in a first plane, wherein the second driven position corresponds to a position of the reflecting means in a second plane, wherein the first plane is substantially parallel to the second plane, and wherein the first plane is in a different plane than the second plane.

16. The modulator of claim 15, wherein the reflecting means comprises a moveable reflector comprising an electrically conductive material.

17. The modulator of claim 16, wherein the second positioning means comprises a set or electrodes.

18. The modulator of claim 15, wherein the modulator substantially absorbs incident visible light when the reflecting means is in the undriven position.

19. The modulator of claim 15, wherein the modulator reflects white light when the reflecting means is in the first driven position.

20. The modulator of claim 15, wherein the modulator selectively reflects light in a range of visible wavelengths associated with a color when the reflecting means is in the second driven position.

21. The modulator of claim 15, further comprising:

means for processing image data, said processing means being in electrical communication with at least one of the first and second positioning means; and

a memory device in electrical communication with the processing means.

22. The modulator of claim 21, further comprising means for sending at least one signal to at least one of the first and second positioning means.

23. The modulator of claim 22, further comprising means for sending at least a portion of the image data to the means for sending at least one signal.

24. The modulator of claim 21, further comprising means for sending the image data to the processor.

25. The modulator of claim 24, wherein the sending means comprises at least one of a receiver, transceiver, and transmitter.

26. The modulator of claim 21, further comprising means for receiving input data and communicating the input data to the processing means.

27. The modulator of claim 15 wherein the second positioning means comprises two electrodes.

28. The modulator of claim 15, wherein the third positioning means is configured to drive the reflecting means to the second driven position through application of a voltage of about 5-15 volts.

29. The modulator of claim 15, wherein the first positioning means is configured to drive the reflecting means to the first driven position through application of a voltage of about 5-15 volts.

30. The modulator of claim 15, wherein the second positioning means is configured to modify the release threshold of the reflecting means through application of a voltage of about 1-10 volts.

31. A method of driving a MEMS device comprising at least a first electrode and at least a second electrode, and a movable electrode positioned between the first electrode and the second electrode and configured to move to at least three 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 driven position;

applying a second voltage potential difference between the second electrode and the movable electrode so as to modify a release threshold of the movable electrode; and

applying a third voltage potential difference between at least a third electrode and the movable electrode so as to drive the movable electrode to a second driven position,

wherein the first driven position corresponds to a position of the moveable electrode in a first plane, wherein the second driven position corresponds to a position of the moveable electrode in a second plane, wherein the first plane is substantially parallel to the second plane, and wherein the first plane is in a different plane than the second plane.

32. the method of claim 31 wherein the first driven position is closer to the first set of electrodes than an undriven position.

33. The method of claim 31, wherein the device substantially absorbs incident visible light when the movable electrode is in an undriven position.

34. The method of claim 31, wherein the device reflects white light when the movable electrode is in the first driven position.

35. The method of claim 31, wherein the device selectively reflects light in a range of visible wavelengths associated with a color when the movable electrode is in the second driven position.

36. The method of claim 31, further comprising processing image data.

37. The method of claim 31, further comprising sending at least one signal to at least one of the first and second electrode.

38. The method of claim 31, further comprising receiving input data.

39. The method of claim 31 wherein the second electrode comprises two electrodes.

40. The method of claim 31, wherein the first voltage potential is about 5-15 volts.

41. The method of claim 31, wherein the third voltage potential is about 5-15 volts.

42. The method of claim 31, wherein the second voltage potential is about 1-10 volts.

43. A method of fabricating a multistate light modulator, the method comprising:

forming first, second, and third electrodes; and

forming a movable reflector comprising an electrically conductive material, the movable reflector positioned between the first and second electrodes, the movable reflector being movable between an undriven position, a first driven position, and a second driven position, wherein the first driven position is closer to the first electrode than are the undriven position and the second driven position, wherein the first electrode is configured to drive the movable reflector to the first driven position, wherein the second electrode is configured to modify a release threshold of the movable reflector, wherein the third electrode is configured to drive the movable reflector to the second driven position, and wherein the first driven position corresponds to a position of the moveable reflector in a first plane, wherein the second driven position corresponds to a position of the moveable reflector in a second plane, wherein the first plane is substantially parallel to the second plane, and wherein the first plane is in a different plane than the second plane.

44. The method of claim 43, wherein forming the moveable reflector comprises forming a fourth electrode.

45. A light modulator manufactured by the method of claim 43.