Capillary Force Actuator Device and Related Method of Applications

• US 20090195120A1
• Filed: 06/06/2007
• Published: 08/06/2009
• Est. Priority Date: 06/06/2006
• Status: Active Grant

• Current Assignee: University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: University of Virginia Patent Foundation (University of Virginia)
• Inventors: Knospe, Carl R.
• Granted Patent: US 8,179,216 B2
• Time in Patent Office: Days
• US Class Current: 310/300
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• 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: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0042 Electric operating means therefor
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: H02N 11/006 Motors

Abstract

An actuator capable of generates force by leveraging the changes in capillary pressure and surface tension that result from the application of an electrical potential. The device, which will be referred to as a Capillary Force Actuator (CFA), and related methods, employs a conducting liquid bridge between two (or more) surfaces, at least one of which contains dielectric-covered electrodes, and operates according to the principles of electro wetting on dielectric.

Claims

1. A capillary force-actuator, comprising:

a first substrate;

an electrode layer disposed on said first substrate;

a dielectric layer disposed on said electrode layer on the side farthest from said first substrate; and

a conducting liquid in communication with said dielectric layer, whereby the capillary pressure within said liquid is reduced by the application of an electric potential and is below ambient pressure with the application of sufficient electrical potential thereby exerting a pulling force on said first substrate when the actuator is in communication with a surface of a system.

2. The actuator of claim 1, further comprising:

a flexible support in communication with said first substrate, whereby said flexible support provides at least one additional force.

3. The actuator of claim 2, wherein said at least one additional force can act in any direction on said first substrate.

4. The actuator of claim 2, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

5. The actuator of claim 2, wherein said flexible support comprises at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

6. The actuator of claim 1, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

7. The actuator of claim 1, wherein the said ambient pressure comprises atmospheric pressure.

8. The actuator of claim 1, wherein said system comprises a MEMS.

9. The actuator of claim 1, wherein said system comprises a valve, a switch, a sensor, a pump, an optical device or any equivalents thereof.

10. A capillary force-actuator, comprising:

a first substrate;

an electrode layer disposed on said first substrate;

a dielectric layer disposed on said electrode layer on the side farthest from said first substrate;

a second substrate; and

a conducting liquid in communication with said dielectric layer of said first substrate and said second substrate, whereby the capillary pressure within said liquid is reduced by the application of an electric potential and is below ambient pressure with the application of sufficient electrical potential thereby exerting a pulling force on said first and second substrates.

11. The actuator of claim 10, further comprising:

a flexible support in communication with at least one of said substrates, whereby said flexible support provides at least one additional force to said first substrate or said second substrate or both said first substrate and said second substrate.

12. The actuator of claim 11, wherein said at least one additional force can act in any direction on said first or second substrates.

13. The actuator of claim 11, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

14. The actuator of claim 11, wherein said flexible support comprises at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

15. The actuator of claim 10, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

16. The actuator of claim 10, wherein the said ambient pressure comprises atmospheric pressure.

17. The actuator of claim 11, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

18. The actuator of claim 17, wherein said substrates are arranged in a parallel fashion.

19. The actuator of claim 17, wherein said substrates are arranged in a hinge-like non-parallel fashion, and wherein multiple electrodes are contained within the said electrode layer, whereby the change in capillary force results in a rotational force on said first and second substrates.

20. The actuator of claim 10, further comprising:

an electrode layer disposed on said second substrate on side of substrate nearest to said conducting liquid; and

a dielectric layer disposed between said electrode layer on side of said electrode layer nearest to said conducting liquid.

21. The actuator of claim 20, further comprising:

a flexible support in communication with at least one of said substrates, whereby said flexible support provides at least one additional force to said first substrate or said second substrate or both said first substrate and said second substrate.

22. The actuator of claim 21, wherein said at least one additional force can act in any direction on said first or second substrates.

23. The actuator of claim 21, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

24. The actuator of claim 21, wherein said flexible support comprises at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

25. The actuator of claim 20, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

26. The actuator of claim 20, wherein the said ambient pressure comprises atmospheric pressure.

27. The actuator of claim 21, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

28. The actuator of claim 27, wherein said substrates are arranged in a parallel fashion.

29. The actuator of claim 27, wherein said substrates are arranged in a hinge-like non-parallel fashion, and wherein multiple electrodes are contained within the said electrode layer, whereby the change in capillary force results in rotational motion of one or both of said substrates.

30. The actuator of claim 20, further comprising:

a third substrate in communication with said conducting liquid; and

whereby said reduction in capillary pressure thereby exerts a force on said third substrate

31. The actuator of claim 30, further comprising:

a flexible support in communication with said third substrate, and

whereby said flexible support provides at least one additional force to said third substrate.

32. The actuator of claim 30, wherein said at least one additional force can act in any direction on said third substrate.

33. The actuator of claim 30, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

34. The actuator of claim 30, wherein said flexible support includes at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

35. The actuator of claim 30, wherein said third substrate comprises a flexible surface, diaphragm, or membrane.

36. The actuator of claim 10, further comprising:

an electrode layer disposed on said second substrate on side of substrate nearest to said conducting liquid;

37. The actuator of claim 36, further comprising:

a flexible support in communication with at least one of said substrates, whereby said flexible support provides at least one additional force to said first substrate or said second substrate or both said first substrate and said second substrate.

38. The actuator of claim 37, wherein said at least one additional force can act in any direction on said first or second substrates.

39. The actuator of claim 37, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

40. The actuator of claim 37, wherein said flexible support comprises at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

41. The actuator of claim 36, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

42. The actuator of claim 36, wherein the said ambient pressure comprises atmospheric pressure.

43. The actuator of claim 37, wherein the ambient environment of said conducting liquid is a less-conductive non-working fluid than said conducting liquid.

44. The actuator of claim 43 where said substrates are arranged in a parallel fashion.

45. The actuator of claim 43, wherein said substrates are arranged in a hinge-like non-parallel fashion, and wherein multiple electrodes are contained within the said electrode layer, whereby the change in capillary force results in rotational motion of one or both of said substrates.

46. The actuator of claim 36, further comprising:

a third substrate in communication with said conducting liquid, whereby said reduction in capillary pressure thereby exerts a force on said third substrate

47. The actuator of claim 46, further comprising:

a flexible support in communication with said third substrate, whereby said flexible support provides at least one additional force to said third substrate.

48. The actuator of claim 46, wherein said at least one additional force can act in any direction on said third substrate.

49. The actuator of claim 46, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

50. The actuator of claim 46, wherein said flexible support comprises at least one of the following:

simple, double or other flexures, cantilever beams, diaphragms, membranes, serpentine springs, leaf springs, hinges, plates, pivots, complaint joints, rotational joints, torsional hinges, folded beams, revolute joints, or translational joints.

51. The actuator of claim 46, wherein said third substrate is a flexible surface, diaphragm, or membrane.

52. The actuator of claim 10, wherein at least one of said surfaces contains a cavity into which said liquid bridge may enter;

and whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer.

53. The actuator of claim 15, wherein at least one of said surfaces contains a cavity into which said liquid bridge may enter, whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer.

54. The actuator of claim 17, wherein at least one of said surfaces contains a cavity into which said liquid bridge may enter, whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer.

55. The actuator of claim 20, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer.

56. The actuator of claim 25, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer of high permittivity.

57. The actuator of claim 27, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer of high permittivity.

58. The actuator of claim 36, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer.

59. The actuator of claim 41, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer of high permittivity.

60. The actuator of claim 43, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer of high permittivity.

61. The actuator of claim 30, wherein at least one of said surfaces covered by the dielectric layer contains a cavity into which said liquid bridge may enter;

whereby said electrode layer is distributed over the surface area of said cavity and covered by said dielectric layer of high permittivity.

62. The actuator of claim 10, wherein said second surface comprises topological features.

63. The actuator of claim 15, wherein said second surface comprises topological features.

64. The actuator of claim 17, where said second surface comprises topological features.

65. The actuator of claim 20, wherein said second surface comprises topological features.

66. The actuator of claim 25, wherein said second surface comprises topological features.

67. The actuator of claim 27, wherein said second surface comprises topological features.

68. The actuator of claim 36, wherein said second surface comprises topological features.

69. The actuator of claim 41, wherein said second surface comprises topological features.

70. The actuator of claim 43, wherein said second surface comprises topological features.

71. The actuator of claim 30, wherein said third surface comprises topological features.

72. The actuator of claim 10, wherein said second surface comprises chemical heterogeneity.

73. The actuator of claim 15, wherein said second surface comprises chemical heterogeneity.

74. The actuator of claim 17, wherein said second surface comprises chemical heterogeneity.

75. The actuator of claim 20, wherein said second surface comprises chemical heterogeneity.

76. The actuator of claim 25, wherein said second surface comprises chemical heterogeneity.

77. The actuator of claim 27, wherein said second surface comprises chemical heterogeneity.

78. The actuator of claim 36, wherein said second surface comprises chemical heterogeneity.

79. The actuator of claim 41, wherein said second surface comprises chemical heterogeneity.

80. The actuator of claim 43, wherein said second surface comprises chemical heterogeneity.

81. The actuator of claim 30, wherein said third surface comprises chemical heterogeneity.

82. The actuator of claim 10, further comprising:

additional electrodes and/or metal layers disposed on;

said first substrate and said second substrate, or

a third substrate in close proximity to said first substrate and said second substrate; and

whereby said additional electrodes and/or metal layers are not in communication with said conducting liquid and said additional electrodes and/or metal layers are positioned opposite each other on;

said first substrate and said second substrate, or

said third substrate.

83. The actuator of claim 82,

wherein said additional electrodes and/or metal layers are arranged in a circularly symmetric arrangement.

84. The actuator of claim 82, further comprising:

a dielectric layer disposed on said additional electrodes and/or metal layers on side furthest from said substrate, and

wherein said additional electrodes and/or metal layers are capable of coming into close proximity or contact with each other with an applied electric potential without coming into communication with the said conductive liquid.

85. The actuator of claim 20, further comprising:

additional electrodes and/or metal layers disposed on;

said first substrate and said second substrate, or

a third substrate in close proximity to said first substrate and said second substrate; and

whereby said additional electrodes and/or metal layers are not in communication with said conducting liquid and said additional electrodes and/or metal layers are positioned opposite each other on;

said first substrate and said second substrate, or

said third substrate.

86. The actuator of claim 85, wherein said additional electrodes and/or metal layers are arranged in a circularly symmetric arrangement.

87. The actuator of claim 85, further comprising:

a dielectric layer disposed on said additional electrodes and/or metal layers on side furthest from said substrate, and

wherein said additional electrodes and/or metal layers are capable of coming into close proximity or contact with each other with an applied electric potential without coming into communication with the said conductive liquid.

88. The actuator of claim 36, further comprising:

additional electrodes and/or metal layers disposed on;

said first substrate and said second substrate, or

a third substrate in close proximity to said first substrate and said second substrate; and

whereby said additional electrodes and/or metal layers are not in communication with said conducting liquid and said additional electrodes and/or metal layers are positioned opposite each other on;

said first substrate and said second substrates, or

said third substrate.

89. The actuator of claim 88, wherein said additional electrodes and/or metal layers are arranged in a circularly symmetric arrangement.

90. The actuator of claim 88, further comprising:

a dielectric layer disposed on said additional electrodes and/or metal layers on side furthest from said substrate, and

wherein said additional electrodes and/or metal layers are capable of coming into close proximity or contact with each other with an applied electric potential without coming into communication with the said conductive liquid.

91. The actuator of claim 30, further comprising:

additional electrodes and/or metal layers disposed on said third substrate; and

a fourth substrate in close proximity to said third substrate, whereby said additional electrodes and/or metal layers are capable of coming into close proximity or contact with each other with an applied electric potential without coming into communication with the said conductive liquid.

92. A method of force actuating, said method comprising:

providing a said first substrate;

providing an electrode layer disposed on said first substrate;

providing a dielectric layer disposed on said electrode layer on the side farthest from said first substrate;

providing a conducting liquid in communication with said dielectric layer of said first substrate;

integrating said first substrate and said conducting liquid into a system, wherein said conducting liquid is in communication with the surface of said system; and

applying an electric potential to reduce the capillary pressure within said conducting liquid with the application of sufficient electrical potential that exerts a pulling force on said first substrate thereby reducing the distance between said first substrate and said surface of said system.

93. The method of claim 92, further comprising:

providing a flexible support in communication with said substrate.

94. The method of claim 93, wherein said at least one additional force can act in any direction on said first substrate.

95. The method of claim 93, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

96. The method of claim 92, wherein said system comprises a MEMS.

97. The method of claim 92, wherein said system comprises a valve, a switch, a sensor, a pump, an optical device or any equivalents thereof.

98. A method of force actuating, said method comprising:

providing a said first substrate;

providing an electrode layer disposed on said first substrate;

providing a dielectric layer disposed on said electrode layer on the side farthest from said first substrate;

providing a said second substrate;

providing a conducting liquid in communication with said dielectric layer of said first substrate and said second substrate; and

applying an electric potential to reduce the capillary pressure within said conducting liquid with the application of sufficient electrical potential that exerts a pulling force on said first and second substrates thereby reducing the distance between said first substrate and said second substrate to provide actuation.

99. The method of claim 98, further comprising:

providing a flexible support in communication with at least one of said substrates.

100. The method of claim 98, wherein said at least one additional force can act in any direction on said first or second substrates.

101. The method of claim 99, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

102. The method of claim 98, further comprising:

providing additional electrodes and/or metal layers on said first and said second substrate such that said additional electrodes and/or metal layers are not in communication with said conducting liquid.

103. A method of capillary actuating, said method comprising:

providing a said first substrate;

providing an electrode layer disposed on said first substrate;

providing a dielectric layer disposed on said electrode layer on the side farthest from said first substrate;

providing a said second substrate;

providing an electrode layer disposed on said second substrate;

providing a dielectric layer disposed on said electrode layer on the side farthest from said second substrate;

providing a conducting liquid in communication with said dielectric layer of said first substrate and said dielectric layer of said second substrate; and

applying an electric potential to reduce the capillary pressure within said conducting liquid with the application of sufficient electrical potential that exerts a pulling force on said first and second substrates thereby reducing the distance between said first substrate and said second substrate to provide actuation.

104. The method of claim 103, further comprising:

providing a flexible support in communication with at least one of said substrates.

105. The method of claim 104, wherein said at least one additional force can act in any direction on said first or second substrates.

106. The method of claim 104, wherein said at least one additional force can act in a direction that opposes or corresponds with said pulling force.

107. The method of claim 103, further comprising:

providing additional electrodes and/or metal layers on both said first and said second substrate such that said additional electrodes and/or metal layers are not in communication with said conducting liquid.