MEMS devices requiring no mechanical support

• US 7,715,079 B2
• Filed: 12/07/2007
• Issued: 05/11/2010
• Est. Priority Date: 12/07/2007
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Kogut, Lior, Tung, Ming-Hau, Tung, Yeh-Jiun
• Primary Examiner(s): Choi; William C
• Application Number:
  US11/952,873
• Publication Number:
  US 20090147343A1
• Time in Patent Office: 886 Days
• Field of Search: 359/198, 359/212, 359/223, 359/247, 359290-292, 359/295, 359/198.1, 359/212.1, 359/223.1
• US Class Current: 359/223.1
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• 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

MEMS devices such as interferometric modulators are described having movable layers that are mechanically isolated. The movable layers are electrically attractable such that they can be selectively moved between a top and bottom electrode through application of a voltage. In interferometric modulators, the movable layers are reflective such that an optically resonant cavity is formed between the layer and a partially reflective layer, thereby providing a display pixel that can be turned on or off depending on the distance between the reflective layers in the resonant cavity.

Claims

1. An electromechanical device, comprising:

a first electrode;

a second electrode, wherein a gap is present between the first and second electrodes; and

a mechanically isolated electrically attractable member positioned within the gap, wherein the electrically attractable member is movable within the gap between a first position closer to the first electrode than the second electrode and a second position closer to the second electrode than the first electrode, wherein the first electrode and electrically attractable member form an interferometric modulator.

2. The electromechanical device of claim 1, comprising a charge transfer element configured to change a charge of the electrically attractable member.

3. The electromechanical device of claim 2, wherein the charge transfer element comprises one or more electrical contacts.

4. The electromechanical device of claim 3, wherein the electrically attractable member does not contact the one or more electrical contacts at a third position between the first and second electrodes.

5. The electromechanical device of claim 3, where the charge transfer element comprises at least one electrical contact positioned to contact the electrically attractable member when it is in the first position, and at least one other electrical contact positioned to contact the electrically attractable member when it is in the second position.

6. The electromechanical device of claim 2, wherein the charge transfer element comprises an electrically conductive coupling connecting the electrically attractable member to a driving circuit.

7. The electromechanical device of claim 2, wherein the charge transfer element comprises a conductive post along which the electrically attractable member is configured to move.

8. The electromechanical device of claim 1, wherein the electrically attractable member is charged.

9. The electromechanical device of claim 1, comprising a post positioned within the gap, wherein the electrically attractable member comprises an opening through which the post extends.

10. The electromechanical device of claim 1, wherein at least one surface of the electrically attractable member is substantially reflective.

11. The electromechanical device of claim 1, wherein the first electrode is partially reflective.

12. The electromechanical device of claim 1, comprising a third electrode coplanar with the first electrode and a fourth electrode coplanar with the second electrode, wherein the first and second electrodes are positioned to overlap with a substantial portion of a first portion of the electrically attractable member and the third and fourth electrodes are positioned to overlap with a substantial portion of a second portion of the electrically attractable member.

13. A display, comprising an array of electromechanical devices that comprise:

a first electrode;

a second electrode, wherein a gap is present between the first and second electrodes; and

a mechanically isolated electrically attractable member positioned within the gap, wherein the electrically attractable member is movable within the gap between a first position closer to the first electrode than the second electrode and a second position closer to the second electrode than the first electrode.

14. The display of claim 13, further comprising:

a processor that is in electrical communication with the array of electromechanical devices, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

15. The display of claim 14, further comprising:

a first controller configured to send at least one signal to the array of electromechanical devices; and

a second controller configured to send at least a portion of said image data to said first controller.

16. The display of claim 14, further comprising an image source module configured to send said image data to said processor.

17. The display of claim 16, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

18. The display of claim 14, further comprising an input device configured to receive input data and to communicate said input data to said processor.

19. An electromechanical device, comprising:

a first electrode, wherein the first electrode is partially reflective;

a second electrode, wherein a gap is present between the first and second electrodes; and

a mechanically isolated electrically attractable member positioned within the gap, wherein the electrically attractable member is movable within the gap between a first position closer to the first electrode than the second electrode and a second position closer to the second electrode than the first electrode.

20. The electromechanical device of claim 19, comprising a charge transfer element configured to change a charge of the electrically attractable member.

21. The electromechanical device of claim 20, wherein the charge transfer element comprises one or more electrical contacts.

22. The electromechanical device of claim 21, wherein the electrically attractable member does not contact the one or more electrical contacts at a third position between the first and second electrodes.

23. The electromechanical device of claim 21, where the charge transfer element comprises at least one electrical contact positioned to contact the electrically attractable member when it is in the first position, and at least one other electrical contact positioned to contact the electrically attractable member when it is in the second position.

24. The electromechanical device of claim 20, wherein the charge transfer element comprises an electrically conductive coupling connecting the electrically attractable member to a driving circuit.

25. The electromechanical device of claim 20, wherein the charge transfer element comprises a conductive post along which the electrically attractable member is configured to move.

26. The electromechanical device of claim 19, wherein the electrically attractable member is charged.

27. The electromechanical device of claim 19, comprising a post positioned within the gap, wherein the electrically attractable member comprises an opening through which the post extends.

28. The electromechanical device of claim 19, wherein at least one surface of the electrically attractable member is substantially reflective.

29. The electromechanical device of claim 19, comprising a third electrode coplanar with the first electrode and a fourth electrode coplanar with the second electrode, wherein the first and second electrodes are positioned to overlap with a substantial portion of a first portion of the electrically attractable member and the third and fourth electrodes are positioned to overlap with a substantial portion of a second portion of the electrically attractable member.

30. An electromechanical device, comprising:

a first electrode;

a second electrode, wherein a gap is present between the first and second electrodes;

a mechanically isolated electrically attractable member positioned within the gap, wherein the electrically attractable member is movable within the gap between a first position closer to the first electrode than the second electrode and a second position closer to the second electrode than the first electrode; and

a charge transfer element configured to change a charge of the electrically attractable member, wherein the charge transfer element comprises a conductive post along which the electrically attractable member is configured to move.

31. The electromechanical device of claim 30, wherein the electrically attractable member is charged.

32. The electromechanical device of claim 30, wherein at least one surface of the electrically attractable member is substantially reflective.

33. The electromechanical device of claim 30, comprising a third electrode coplanar with the first electrode and a fourth electrode coplanar with the second electrode, wherein the first and second electrodes are positioned to overlap with a substantial portion of a first portion of the electrically attractable member and the third and fourth electrodes are positioned to overlap with a substantial portion of a second portion of the electrically attractable member.

34. An electromechanical device, comprising:

a first electrode;

a second electrode, wherein a gap is present between the first and second electrodes;

a mechanically isolated electrically attractable member positioned within the gap, wherein the electrically attractable member is movable within the gap between a first position closer to the first electrode than the second electrode and a second position closer to the second electrode than the first electrode; and

a post positioned within the gap, wherein the electrically attractable member comprises an opening through which the post extends.

35. The electromechanical device of claim 34, comprising a charge transfer element configured to change a charge of the electrically attractable member.

36. The electromechanical device of claim 35, wherein the charge transfer element comprises one or more electrical contacts.

37. The electromechanical device of claim 36, wherein the electrically attractable member does not contact the one or more electrical contacts at a third position between the first and second electrodes.

38. The electromechanical device of claim 36, where the charge transfer element comprises at least one electrical contact positioned to contact the electrically attractable member when it is in the first position, and at least one other electrical contact positioned to contact the electrically attractable member when it is in the second position.

39. The electromechanical device of claim 35, wherein the charge transfer element comprises an electrically conductive coupling connecting the electrically attractable member to a driving circuit.

40. The electromechanical device of claim 35, wherein the charge transfer element comprises a conductive post along which the electrically attractable member is configured to move.

41. The electromechanical device of claim 34, wherein the electrically attractable member is charged.

42. The electromechanical device of claim 34, wherein at least one surface of the electrically attractable member is substantially reflective.

43. The electromechanical device of claim 34, comprising a third electrode coplanar with the first electrode and a fourth electrode coplanar with the second electrode, wherein the first and second electrodes are positioned to overlap with a substantial portion of a first portion of the electrically attractable member and the third and fourth electrodes are positioned to overlap with a substantial portion of a second portion of the electrically attractable member.