Distributed MEMS electrostatic pumping devices

• US 6,485,273 B1
• Filed: 09/01/2000
• Issued: 11/26/2002
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: Research Triangle Institute
• Original Assignee: MCNC, Inc.
• Inventors: Goodwin-Johansson, Scott H.
• Primary Examiner(s): KOCZO JR, MICHAEL
• Application Number:
  US09/654,446
• Time in Patent Office: 816 Days
• Field of Search: 417/410.1, 417/413.1, 417/410.2, 417/413.3, 417/322, 417/540, 417/436, 310/309
• US Class Current: 417/410.2
• CPC Class Codes: F04D 33/00 Non-positive-displacement pumps with other than pure rotation, e.g. of oscillating type F04D35/00 takes precedence; hand-held fans A45B

Abstract

A MEMS pumping device driven by electrostatic forces comprises a substrate having at least one substrate electrode disposed thereon. Affixed to the substrate is a moveable membrane that generally overlies the at least one substrate electrode. The moveable membrane comprises at least one electrode element and a biasing element. The moveable membrane includes a fixed portion attached to the substrate and a distal portion extending from the fixed portion and being moveable with respect to the substrate electrode. A dielectric element is disposed between the at least one substrate electrode and the at least one electrode element of the moveable membrane to provide for electrical isolation. In operation, a voltage differential is established between the at least one substrate electrode and the at least one electrode element which displaces the moveable membrane relative to the substrate to thereby controllably distribute matter residing between the substrate and the distal portion of the moveable membrane. In a further embodiment the MEMS pumping devices comprise more that two moveable membranes that are configured so as to maximize flow in a desired direction. Additional embodiments include more than one electrode element disposed within the moveable membrane that are capable of individual and sequential biasing to improve overall net flow in the desired flow direction.

Claims

1. A MEMS (Micro Electro Mechanical System) electrostatic pump device, comprising:

a substrate;

a plurality of individually addressable substrate electrodes disposed upon said substrate;

a first moveable membrane generally overlying said plurality of individually addressable substrate electrodes, the first moveable membrane comprising at least one electrode element and a biasing element, wherein the first moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said plurality of individually addressable substrate electrodes; and

a dielectric element disposed between said plurality of individually addressable substrate electrodes and said at least one electrode element of said first moveable membrane,

wherein a voltage differential established between said plurality of individually addressable substrate electrodes and said at least one electrode element moves said first moveable membrane relative to said substrate to thereby controllably distribute matter residing between the substrate and the distal portion of said first moveable membrane.

2. The MEMS electrostatic pump device of claim 1, further comprising a second moveable membrane, the second moveable membrane comprising at least one electrode element and a biasing element, wherein the second moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said plurality of individually addressable substrate electrodes.

3. The MEMS electrostatic pump device of claim 2, wherein the first and second moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first and second membranes.

4. The MEMS electrostatic pump device of claim 2, wherein said second moveable membrane is disposed on said substrate adjacent to said first moveable membrane.

5. The MEMS electrostatic pump device of claim 2, wherein said first and second moveable membranes have generally rectangular top plan view shapes and generally equivalent top plan view areas.

6. The MEMS electrostatic pump device of claim 1, wherein said at least one electrode element of said first moveable membrane further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first moveable membrane.

7. The MEMS electrostatic pump device of claim 2, wherein said at least one electrode element of said first and second moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first and second moveable membranes, respectively.

8. The MEMS electrostatic pump device of claim 1, further comprising second and third moveable membranes, each of the second and third moveable membranes comprising an electrode element and a biasing element, wherein each of the second and third moveable membranes includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said plurality of individually addressable substrate electrodes.

9. The MEMS electrostatic pump device of claim 8, wherein the first, second and third moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first, second and third moveable membranes.

10. The MEMS electrostatic pump device of claim 8, wherein said second and third moveable membranes are disposed adjacent to opposite sides of said first moveable membrane.

11. The MEMS electrostatic pump device of claim 8, wherein said first moveable membrane has a generally rectangular top plan view shape and said second and third moveable membranes have a generally triangular top plan view shape.

12. The MEMS electrostatic pump device of claim 11, wherein said second and third moveable membranes have a generally equivalent top plan view area.

13. The MEMS electrostatic pump device of claim 11, wherein said first, second and third moveable membranes are disposed on said substrate such that a top plan view side of said second moveable membrane and a top plan view side of said third moveable membrane are adjacent to opposite top plan view sides of said first moveable membrane in the direction of movement.

14. The MEMS electrostatic pump device of claim 8, wherein said at least one electrode element of said first moveable membrane further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first moveable membrane.

15. The MEMS electrostatic pump device of claim 8, wherein said at least one electrode element of said first, second and third moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first, second and third moveable membranes.

16. The MEMS electrostatic pump device of claim 1, further comprising a second, third and fourth moveable membrane, each of the second, third and fourth moveable membranes comprising an electrode element and a biasing element, wherein each of the second, third and fourth moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said plurality of individually addressable substrate electrodes.

17. The MEMS electrostatic pump device of claim 16, wherein the first, second, third and fourth moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first, second, third and fourth moveable membrane.

18. The MEMS electrostatic pump device of claim 16, wherein said first and second moveable membranes have a generally equal-area, rectangular plan view shape and said third and fourth moveable membranes have a generally equal-area, triangular plan view shape.

19. The MEMS electrostatic pump device of claim 16, wherein said first and second, moveable membranes are disposed on said substrate such that top plan view sides of said first and second moveable membranes are adjacent in the direction of movement.

20. The MEMS electrostatic pump device of claim 16, wherein said third and fourth moveable membranes are disposed on said substrate such that one side of said third moveable membrane is adjacent to a side of said first moveable membrane that is opposite said second moveable membrane and one side of said fourth moveable membrane is adjacent to a side of said second moveable membrane that is opposite said first moveable membrane.

21. The MEMS electrostatic pump device of claim 16, wherein said at least one electrode element of said first and second moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first and second moveable membranes.

22. The MEMS electrostatic pump device of claim 16, wherein said at least one electrode element of said first, second, third and fourth moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first, second, third and fourth moveable membranes.

23. The MEMS electrostatic PUMP device according to claim 1, wherein said at least one electrode element and said biasing element have different thermal coefficients of expansion.

24. The MEMS electrostatic pump device according to claim 1, wherein said biasing element comprises at least two polymer films of different thickness.

25. The MEMS electrostatic pump device according to claim 1, wherein said biasing element comprises at least two polymer films of different thermal coefficients of expansion.

26. The MEMS electrostatic pump device according to claim 1, wherein the distal portion of said moveable membrane is biased so as to curl away from said substrate in the absence of an electrostatic force between said electrode element and said plurality of individually addressable substrate electrodes.

27. The MEMS electrostatic pump device according to claim 1, wherein the distal portion of said moveable membrane is biased so as to curl toward said substrate in the absence of an electrostatic force between said electrode element and said plurality of individually addressable substrate electrodes.

28. The MEMS electrostatic pump device according to claim 1, further comprising a source of electrostatic energy electrically connected to at least one of said plurality of individually addressable substrate electrodes and said at least one electrode element.

29. A MEMS electrostatic pump device, comprising:

a substrate;

at least one substrate electrode disposed upon said substrate;

a first moveable membrane having a generally rectangular top plan view shape that generally overlies said at least one substrate electrode;

a second moveable membrane having a generally rectangular top plan view shape that generally overlies said at least one substrate electrode;

a third moveable membrane having a generally triangular top plan view shape that generally overlies said at least one substrate electrode;

a fourth moveable membrane having a generally triangular top plan view shape that generally overlies said at least one substrate electrode, wherein said first, second, third and fourth moveable membranes each comprise at least one electrode element and a biasing element, wherein said first, second, third and fourth moveable membranes each include a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode; and

a dielectric element disposed between said at least one substrate electrode and said at least one electrode element of said first, second, third and fourth moveable membranes,

whereby a voltage differential established between said at least one substrate electrode and said at least one electrode element of said first, second, third and fourth moveable membranes moves said first, second, third and fourth moveable membranes relative to said substrate to thereby controllably distribute matter residing between the substrate and the distal portion of said first, second, third and fourth moveable membranes.

30. A MEMS (Micro Electro Mechanical System) electrostatic pump device, comprising:

a substrate;

at least one substrate electrode disposed upon said substrate;

a first moveable membrane generally overlying said at least one substrate electrode, the first moveable membrane comprising a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first moveable membrane and a biasing element, wherein the first moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode; and

a dielectric element disposed between said at least one substrate electrode and said at least one electrode element of said first moveable membrane,

wherein a voltage differential established between said at least one substrate electrode and said at least one of said plurality of individually addressable electrode elements moves said first moveable membrane relative to said substrate to thereby controllably distribute matter residing between the substrate and the distal portion of said first moveable membrane.

31. The MEMS electrostatic pump device of claim 30, further comprising a second moveable membrane, the second moveable membrane comprising at least one electrode element and a biasing element, wherein the second moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode.

32. The MEMS electrostatic pump device of claim 31, wherein the first and second moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first and second membranes.

33. The MEMS electrostatic pump device of claim 31, wherein said second moveable membrane is disposed on said substrate adjacent to said first moveable membrane.

34. The MEMS electrostatic pump device of claim 31, wherein said at least one substrate electrode further comprise a first substrate electrode generally underlying said first moveable membrane and a second substrate electrode generally underlying said second moveable membrane.

35. The MEMS electrostatic pump device of claim 30, wherein said at least one substrate electrode further comprise a plurality of individually addressable substrate electrodes disposed upon said substrate and corresponding to said plurality of individually addressable electrode elements in said first moveable membrane to controllably activate predetermined regions in the first moveable membrane.

36. The MEMS electrostatic pump device of claim 31, wherein said at least one electrode element of the second moveable membrane further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the second moveable membrane.

37. The MEMS electrostatic pump device of claim 30, further comprising second and third moveable membranes, each of the second and third moveable membranes comprising an electrode element and a biasing element, wherein each of the second and third moveable membranes includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode.

38. The MEMS electrostatic pump device of claim 37, wherein the first, second and third moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first, second and third moveable membranes.

39. The MEMS electrostatic pump device of claim 37, wherein said second and third moveable membranes are disposed on the substrate adjacent to opposite sides of said first moveable membrane.

40. The MEMS electrostatic pump device of claim 37, wherein said at least one substrate electrode further comprises a first substrate electrode generally underlying said first moveable membrane, a second substrate electrode generally underlying said second moveable membrane and a third substrate electrode generally underlying said third moveable membrane.

41. The MEMS electrostatic pump device of claim 37, wherein said at least one electrode element of said second and third moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the second and third moveable membranes.

42. The MEMS electrostatic pump device of claim 41, wherein said at least one substrate electrode further comprise a plurality of individually addressable substrate electrodes disposed upon said substrate corresponding to the plurality of individually addressable electrode elements in the first, second and third moveable membranes to controllably activate predetermined regions in the first, second and third moveable membranes.

43. The MEMS electrostatic pump device of claim 30, further comprising second, third and fourth moveable membranes, each of the second, third and fourth moveable membranes comprising an electrode element and a biasing element, wherein each of the second, third and fourth moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode.

44. The MEMS electrostatic pump device of claim 43, wherein the first, second, third and fourth moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first, second, third and fourth moveable membrane.

45. The MEMS electrostatic pump device of claim 43, wherein said at least one substrate electrode further comprises a first substrate electrode generally underlying said first moveable membrane, a second substrate electrode generally underlying said second moveable membrane, a third substrate electrode generally underlying said third moveable membrane and a fourth substrate electrode generally underlying said fourth moveable membrane.

46. The MEMS electrostatic pump device of claim 43, wherein said at least one electrode element of said second, third and fourth moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first, second, third and fourth moveable membranes.

47. The MEMS electrostatic pump device of claim 46, wherein said at least one substrate electrode further comprise a plurality of individually addressable substrate electrodes disposed upon said substrate and corresponding to said plurality of individually addressable electrode elements of said first, second, third, fourth moveable membranes to controllably activate predetermined regions in the first, second, third and fourth moveable membranes.

48. A MEMS (Micro Electro Mechanical System) electrostatic pump device, comprising:

a substrate;

at least one substrate electrode disposed upon said substrate;

a first moveable membrane generally overlying said at least one substrate electrode, the first moveable membrane comprising at least one electrode element and a biasing element that includes two polymer film layers on opposite sides of said at least one electrode element, wherein the first moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode; and

a dielectric element disposed between said at least one substrate electrode and said at least one electrode element of said first moveable membrane,

wherein a voltage differential established between said at least one substrate electrode and said at least one electrode element moves said first moveable membrane relative to said substrate to thereby controllably distribute matter residing between the substrate and the distal portion of said first moveable membrane.

49. The MEMS electrostatic pump device of claim 48, further comprising a second moveable membrane, the second moveable membrane comprising at least one electrode element and a biasing element, wherein the second moveable membrane includes a fixed portion attached to said substrate and a distal portion extending from the fixed portion, the distal portion being moveable with respect to said substrate electrode.

50. The MEMS electrostatic pump device of claim 49, wherein the first and second moveable membranes controllably move relative to said substrate to thereby distribute matter residing between the substrate and the distal portions of said first and second membranes.

51. The MEMS electrostatic pump device of claim 49, wherein said second moveable membrane is disposed on said substrate adjacent to said first moveable membrane.

52. The MEMS electrostatic pump device of claim 49, wherein said at least one substrate electrode further comprise a first substrate electrode generally underlying said first moveable membrane and a second substrate electrode generally underlying said second moveable membrane.

53. The MEMS electrostatic pump device of claim 48, wherein said at least one electrode element of said first moveable membrane further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first moveable membrane.

54. The MEMS electrostatic pump device of claim 48, wherein said at least one substrate electrode further comprise a plurality of individually addressable substrate electrodes disposed upon said substrate to controllably activate predetermined regions in the first moveable membrane.

55. The MEMS electrostatic pump device of claim 49, wherein said at least one electrode element of said first and second moveable membranes further comprise a plurality of individually addressable electrode elements to controllably activate predetermined regions in the first and second moveable membranes, respectively.

56. The MEMS electrostatic pump device of claim 49, wherein said at least one substrate electrode further comprise a plurality of individually addressable substrate electrodes disposed upon said substrate to controllably activate predetermined regions in the first and second moveable membranes.

57. The MEMS electrostatic pump device according to claim 48, wherein the distal portion of said moveable membrane is biased so as to curl away from said substrate in the absence of an electrostatic force between said electrode element and said substrate electrode.

58. The MEMS electrostatic pump device according to claim 48, further comprising a source of electrostatic energy electrically connected to at least one of said substrate electrode and said at least one electrode element.