Multi-directional thermal actuator

• US 6,438,954 B1
• Filed: 04/27/2001
• Issued: 08/27/2002
• Est. Priority Date: 04/27/2001
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Pendergrass, Daniel B., Weaver, Billy L., Theiss, Silva K., Goetz, Douglas P., Smith, Robert G., Hamerly, Mike E.
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US09/845,188
• Time in Patent Office: 487 Days
• Field of Search: 605/27, 605/28, 310/306, 310/307, 310/309
• US Class Current: 60/527
• CPC Class Codes: B81B 2201/031 Thermal actuators
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• 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: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01G 5/40 Structural combinations of variable capacitors with other electric elements not covered by this subclass, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01H 2061/008 Micromechanical actuator with a cold and a hot arm, coupled together at one end

Abstract

A micrometer sized multi-directional thermal actuator capable of repeatable and rapid displacement in a substantially horizontal direction, a substantially vertical direction, and/or a combination thereof. The multi-directional thermal actuator constructed on a surface of a substrate includes three or more beams each cantilevered from one or more anchors at a first end to extend generally parallel to the surface of the substrate. A member mechanically and electrically couples the distal ends of the beams. Application of current to a circuit comprising combinations of any two or more of the beams displaces the member in one of three or more non-parallel radial directions, respectively.

Claims

1. A multi-directional thermal actuator constructed on a surface of a substrate, the apparatus comprising:

a first beam cantilevered from an anchor at a first end to extend generally parallel to the surface of the substrate in an unactivated configuration;

a second beam cantilevered from an anchor at a first end to extend generally parallel to the surface of the substrate in an unactivated configuration;

a third beam cantilevered from an anchor at a first end to extend generally parallel to the surface of the substrate in an unactivated configuration, wherein the first, second, and third beams are not coplanar;

a member mechanically coupling distal ends of the first, second, and third beams;

a first circuit comprising at least the first beam, whereby application of current to the first circuit displaces the member in a first radial direction;

a second circuit comprising at least the second beam, whereby application of current to the second circuit displaces the member in a second radial direction; and

a third circuit comprising at least the third beam, whereby application of current to the third circuit displaces the member in a third radial direction.

2. The apparatus of claim 1 comprising a grounding tab electrically coupling one or more of the beams to the substrate.

3. The apparatus of claim 1 comprising a resistance located between one or more of the beams and ground.

4. The apparatus of claim 1 wherein the first circuit comprises the first and second beams.

5. The apparatus of claim 1 wherein the second circuit comprises the second and third beams.

6. The apparatus of claim 1 wherein the third circuit comprises the third and first beams.

7. The apparatus of claim 1 wherein the first beam and a grounding tab comprises a fourth circuit, whereby application of current to the fourth circuit displaces the member in a fourth radial direction.

8. The apparatus of claim 1 wherein the second beam and a grounding tab comprise a fifth circuit, whereby application of current to the fifth circuit displaces the member in a fifth radial direction.

9. The apparatus of claim 1 wherein the third beam and a grounding tab comprise a sixth circuit, whereby application of current to the sixth circuit displaces the member in a sixth radial direction.

10. The apparatus of claim 1 comprising at least a fourth beam cantilevered from an anchor at a first end to extend generally parallel to the surface of the substrate in an unactivated configuration, the fourth beam being mechanically coupled to the member.

11. The apparatus of claim 10 comprising:

a seventh circuit comprising the first and fourth beams, whereby application of current to the seventh circuit displaces the member in a seventh radial direction;

an eighth circuit comprising the second and fourth beams, whereby application of current to the eighth circuit displaces the member in a eighth radial direction; and

a ninth circuit comprising the third and fourth beams, whereby application of current to the ninth circuit displaces the member in a ninth radial direction.

12. The apparatus of claim 11 comprising a tenth circuit comprising the first, second, and third beams, whereby application to the tenth circuit displaces the member in a tenth radial direction.

13. The apparatus of claim 12 wherein the tenth circuit comprises a third current density in the first beam and a fourth current density in the second beam less than the third current density resulting in displacement of the member in a eleventh radial direction.

14. The apparatus of claim 1 comprising a cold arm have a first end anchored to the surface of the substrate and a distal end mechanically coupled to the member.

15. The apparatus of claim 1 comprising a cold arm have a first end anchored to the surface of the substrate and a distal end mechanically and electrically coupled to the member.

16. The apparatus of claim 1 wherein the first, second, and third beams comprise a symmetrical cross-sectional configuration.

17. The apparatus of claim 1 wherein the first, second, and third beams comprise an asymmetrical cross-sectional configuration.

18. The apparatus of claim 10 wherein the first, second, third and fourth beams comprise a generally rectangular cross-sectional configuration.

19. The apparatus of claim 1 comprising a plurality of multi-directional thermal actuators on the substrate.

20. A multi-directional thermal actuator constructed on a surface of a substrate, the apparatus comprising:

at least three beams each cantilevered from one or more anchors at a first end to extend generally parallel to the surface of the substrate in an unactivated state, wherein at least one of the beams is not coplanar with the other two beams; and

a member mechanically coupling distal ends of the beams, whereby application of current to a circuit comprising combinations of any two or more of the beams displaces the member in one of three or more non-parallel radial directions, respectively.

21. A multi-directional thermal actuator constructed on a surface of a substrate, the apparatus comprising:

four beams each cantilevered from one or more anchors at a first end to extend generally parallel to the surface of the substrate, the beams being arranged in a generally rectangular cross-sectional configuration; and

a member mechanically coupling distal ends of the beams.

22. The apparatus of claim 21 wherein two of the beams comprise upper beams and two of the beams comprise lower beams, the two upper beams being arranged above the two lower beams relative to the surface of the substrate.

23. The apparatus of claim 22 wherein the actuator exhibits vertically upward displacement when current is applied to the two lower beams.

24. The apparatus of claim 22 wherein the actuator exhibits vertically downward displacement when current is applied to the two upper beams.

25. The apparatus of claim 22 wherein the actuator exhibits horizontal displacement when current is applied to one of the lower beams and the upper beam located above the lower beam.

26. The apparatus of claim 21 wherein one of the beams is arranged above another of the beams and two of the beams are laterally offset therefrom.

27. The apparatus of claim 21 wherein the actuator exhibits both horizontal and vertical displacement when current is applied to any three of the beams.

28. The apparatus of claim 21 comprising a cold arm having a first end anchored to the surface and a distal end attached to the member, the cold arm being located generally parallel with the beams and within a generally rectangular space bounded by the beams.

29. The apparatus of claim 21 comprising a cold arm centrally located relative to the beams, the cold arm having a first end anchored to the surface and a distal end connected to the member.

30. The apparatus of claim 21 comprising a cold arm symmetrically located relative to the beams, the cold arm having a first end anchored to the surface and a distal end connected to the member.

31. The apparatus of claim 21 comprising a cold arm having a first end anchored to the surface and a distal end attached to the member.

32. The apparatus of claim 31 comprising a flexure formed in the cold arm near the first end thereof adapted to provide controlled bending.

33. The apparatus of claim 32 wherein the flexure comprises at least one of a recess, depression, cut-out, hole, location of narrowed, thinned or weakened material, alternate material or other structural features or material change that decreases resistance to bending in that location.

34. The apparatus of claim 31 comprising a reinforcing member formed in the cold arm.

35. The apparatus of claim 34 wherein the reinforcing member is integrally formed in the cold arm.

36. The apparatus of claim 31 comprising a metal layer extending along the cold arm.

37. The apparatus of claim 31 wherein the cold arm is electrically isolated from the beams.

38. The apparatus of claim 31 wherein the beams and the cold arm comprise a circuit through which electric current is passed.

39. The apparatus of claim 31 wherein the actuator exhibits both horizontal and vertical displacement when current is applied to a circuit comprising the cold arm and any one of the beams.

40. The apparatus of claim 31 wherein the actuator exhibits both horizontal and vertical displacement when current is applied to a circuit comprising the cold arm and any three of the beams.

41. The apparatus of claim 31 wherein the cold arm exhibits a lower current density than the beams at a given voltage.

42. The apparatus of claim 21 comprising a grounding tab electrically coupling one or more of the beams to the substrate.

43. The apparatus of claim 21 comprising a plurality of multi-directional thermal actuators on the substrate.

44. The apparatus of claim 21 comprising at least one optical device mechanically coupled to the multi-directional thermal actuator.

45. The apparatus of claim 44 wherein the optical device comprises one of a reflector, a lens, a polarizer, a wave guide, a shutter, or an occluding structure.

46. The apparatus of claim 44 comprising an optical communication system including at least one optical device.