Thermomechanical in-plane microactuator

• US 6,734,597 B1
• Filed: 12/18/2002
• Issued: 05/11/2004
• Est. Priority Date: 06/19/2000
• Status: Expired due to Term

• Current Assignee: Longhorn HD LLC (Alpha Alpha Intellectual Partners LLC)
• Original Assignee: Brigham Young University (The Church of Jesus Christ of Latter-Day Saints)
• Inventors: Howell, Larry L., Lyon, Scott
• Primary Examiner(s): Nguyen, Tran
• Application Number:
  US10/312,172
• Publication Number:
  US 20040074234A1
• Time in Patent Office: 510 Days
• Field of Search: 310/306, 310/307, 310/309, 605/27, 605/28, 361/160-164, 360/294.4, 360/294.6
• US Class Current: 310/306
• CPC Class Codes: B81B 2201/031 Thermal actuators
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 3/0037 For increasing stroke, i.e. achieve large displacement of actuated parts
• CPC Class Codes: F03G 7/06 using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like using thermal expansion of non-vaporising liquids F01K
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 61/00 Electrothermal relays thermal switches not operated by electrical input, thermal switches with anticipating electrical input H01H37/00; thermally-sensitive members H01H37/32
• CPC Class Codes: H02N 10/00 Electric motors using thermal effects motors using expansion or contraction of bodies due to heating or cooling F03G7/06

Abstract

A microactuator providing an output force and displacement in response to an increase in thermal energy is displosed. The microactuator may have a substantially straight expansion member with a first and a second end. The first end may be coupled to a base member, and the second end may be coupled to a shuttle. The expansion member is capable of elongating in a elongation direction. Elongation of the expansion member may urge the shuttle to translate in an output direction substantially different than the elongation direction. In certain embodiments, multiple expansion members are arrayed along one side of the shuttle to drive the shuttle against a surface. Alternatively, expansion members may be disposed on both sides of the shuttle to provide balanced output force. If desired, multiple microactuators may be linked together to multiply the output displacement and/or output force.

Claims

1. A microelectromechanical mechanism comprising:

a base member;

a shuttle; and

a substantially straight expansion member attached to the base member and the shuttle, such that the base member, the shuttle, and the expansion member substantially form an “

I”

shape, wherein the expansion member is configured to elongate in an elongation direction to drive a shuttle in a direction substantially different from the elongation direction.

2. The microelectromechanical mechanism of claim 1, further comprising:

a second base member; and

a second substantially straight expansion member attached to the second base member and the shuttle, such that the second base member, the shuttle, and the second expansion member substantially form an “

I”

shape.

3. The microelectromechanical mechanism of claim 1, wherein the shuttle is configured to act as a base member for a second microelectromechanical mechanism comprising a second shuttle and a second substantially straight expansion member wherein a second shuttle of the second microelectromechanical mechanism has an amplified displacement.

4. The microelectromechanical mechanism of claim 1, wherein the shuttle abuts a surface, the surface guiding a direction of travel of the shuttle.

5. The microelectromechanical mechanism of claim 4, wherein the surface comprises a plurality of teeth, the shuttle comprising teeth, configured to mesh with the teeth of the surface.

6. The microelectromechanical mechanism of claim 4, wherein the surface is substantially smooth.

7. The microelectromechanical mechanism of claim 1, wherein elongation of the expansion member is induced by an electrical current passing through the expansion member.

8. The microelectromechanical mechanism of claim 1, wherein the fixed base member and the shuttle are electrically coupled to an electrical current source.

9. The microelectromechanical mechanism of claim 2, wherein at least two base members are electrically coupled to an electrical current source.

31. The microelectromechanical mechanism of claim 1, wherein the expansion member is configured to buckle during elongation.

32. The microelectromechanical mechanism of claim 1, further comprising a second expansion member connected to the base member and the shuttle.

33. The microelectromechanical mechanism of claim 32, wherein the second expansion member is disposed substantially parallel to the expansion member.

34. The microelectromechanical mechanism of claim 33, wherein first and second expansion members are grouped close together to prevent heat loss.

35. The microelectromechanical mechanism of claim 1, wherein elongation of the expansion member is induced by an ambient temperature increase.

36. The microelectromechanical mechanism of claim 1, wherein the expansion member has a width that varies along a length of the expansion member.

37. The microelectromechanical mechanism of claim 36, wherein the expansion member has an increased width of a central portion of the expansion member.

38. The microelectromechanical mechanism of claim 1, wherein the expansion member and the shuttle are integrally formed through a single manufacturing process.

39. The microelectromechanical mechanism of claim 1, wherein the expansion member has a material and shape selected to permit cyclical deflection of the expansion member with no substantial plastic deformation of the expansion member.

40. The microelectromechanical mechanism of claim 1, wherein the base member is at a fixed place.

41. The microelectromechanical mechanism of claim 40, wherein the base member is affixed on a silicon wafer.

42. The microelectromechanical mechanism of claim 40, wherein the base member is affixed to another microelectromechanical mechanism.

43. The microelectromechanical mechanism of claim 1, wherein the expansion member is configured to actuate the shuttle when thermal energy in the expansion member decreases.

10. A microelectromechanical mechanism comprising:

a substantially straight expansion member comprising a first and a second end;

a base member attached to the first end of the substantially straight expansion member; and

a shuttle attached to the second end of the substantially straight expansion member, such that the expansion member is able to elongate in an elongation direction to bias the shuttle in an output direction substantially different from the elongation direction.

11. The microelectromechanical mechanism of claim 10, further comprising:

a second base member; and

a second substantially straight expansion member comprising a first end attached to the second base member and a second end attached to the shuttle.

12. The microelectromechanical mechanism of claim 10, wherein the shuttle is configured to act as a base member for a second microelectromechanical mechanism comprising a second shuttle and a second substantially straight expansion member wherein a second shuttle of the second microelectromechanical mechanism has an amplified displacement.

13. The microelectromechanical mechanism of claim 10, wherein the shuttle abuts a surface, the surface guiding a direction of travel of the shuttle.

14. A microelectromechanical mechanism comprising:

an expansion member comprising a first end and a second end;

a base member attached to the first end of the expansion member; and

a shuttle attached to the second end of the expansion member, such that elongation of the expansion member in an expansion direction induces motion of the shuttle in an output direction, wherein elongation of the expansion member further induces buckling of the expansion member.

15. The microelectromechanical mechanism of claim 14, wherein the expansion member is configured to buckle elastically.

16. The microelectromechanical mechanism of claim 14, wherein the expansion member is configured to substantially buckle in an “

S”

shape.

17. The microelectromechanical mechanism of claim 14, further comprising:

a second base member; and

a second substantially straight expansion member comprising a first end attached to the second base member and a second end attached to the shuttle.

18. The microelectromechanical mechanism of claim 14, wherein the shuttle is configured to act as a base member for a second microelectromechanical mechanism comprising a second shuttle and a second expansion member wherein a second shuttle of the second microelectromechanical mechanism has an amplified displacement.

19. The microelectromechanical mechanism of claim 14, wherein the shuttle abuts a surface, the surface guiding a direction of the travel of the shuttle.

20. A microelectromechanical mechanism comprising:

an expansion member comprising a first end configured to be attached to a structure and a second end configured to travel in a substantially linear path during elongation of the expansion member in an expansion direction; and

a shuttle connected to the second end such that the second end is able to bias the shuttle in an output direction in response to elongation of the expansion member.

21. The microelectromechanical mechanism of claim 20, further comprising:

a second expansion member comprising a first end configured to be fixed in place and a second end configured to travel in a substantially linear path during elongation of the second expansion member in an expansion direction.

22. The microelectromechanical mechanism of claim 20, wherein the shuttle is configured to act as a structure to attach a second microelectromechanical mechanism comprising a second shuttle and a second expansion member wherein a second shuttle of the second microelectromechanical mechanism has an amplified displacement.

23. The microelectromechanical mechanism of claim 20, wherein the shuttle abuts a surface, the surface guiding a direction of travel of the shuttle.

24. The microelectromechanical mechanism of claim 20, wherein elongation of the expansion member is induced by an electrical current passing through the expansion member.

25. A microelectromechanical mechanism comprising:

a base member;

a shuttle; and

an expansion member comprising a first end and a second end, the first end substantially perpendicularly attached to the base member and the second end substantially perpendicularly attached to the shuttle, the expansion member is able to elongate in an elongation direction to bias the shuttle in an output direction substantially different from the elongation direction.

26. The microelectromechanical mechanism of claim 25, wherein the first end is attached to the base member at an angle less than ±

15 degrees from exactly perpendicular attachment.

27. The microelectromechanical mechanism of claim 25, further comprising:

a second base member; and

a second expansion member comprising a first end substantially perpendicularly attached to the second base member and a second end substantially perpendicularly attached to the shuttle.

28. The microelectromechanical mechanism of claim 25, wherein the shuttle is configured to act as a base member for a second microelectromechanical mechanism comprising a second shuttle and a second expansion member wherein a second shuttle of the second microelectromechanical mechanism has an amplified displacement.

29. The microelectromechanical mechanism of claim 25, wherein the shuttle abuts a surface, the surface guiding a direction of travel of the shuttle.

30. The microelectromechanical mechanism of claim 25, wherein elongation of the expansion member is induced by an electrical current passing through the expansion member.

44. A method for actuating a micromechanism, the micromechanism comprising an expansion member having a first end coupled to a base member and a second end coupled to a drivable shuttle, the method comprising:

elongating the expansion member in an elongation direction;

elastically buckling the expansion member against the shuttle;

applying a biasing force resulting from buckling of the expansion member to the shuttle, a portion of the biasing force urging the shuttle in a direction substantially different from the elongation direction.

45. A method for actuating a micromechanism, the micromechanism comprising an expansion member having a first end coupled to a base member and a second end coupled to a drivable shuttle, the method comprising:

providing an energy source; and

disposing the energy source in communication with the expansion member to elongate the expansion member such that the expansion member buckles to bias the shuttle in an output direction substantially different from the elongation direction.

46. A method for actuating a micromechanism, the micromechanism comprising an expansion member, a base member, and a drivable shuttle, the method comprising:

fixing a lateral distance between the base member and the shuttle;

disposing the expansion member substantially perpendicular to the base member and the shuttle; and

elongating the expansion member such that the expansion member presses against the shuttle, the expansion member moving from a substantially perpendicular disposition to displace the shuttle.