Actuators including serpentine arrangements of alternating actuating and opposing segments and related methods

• US 6,327,855 B1
• Filed: 02/04/2000
• Issued: 12/11/2001
• Est. Priority Date: 02/04/2000
• Status: Expired due to Fees

• Current Assignee: Memscap Incorporated
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Hill, Edward A., Dhuler, Vijayakumar Rudrappa
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US09/498,100
• Time in Patent Office: 676 Days
• Field of Search: 605/27, 605/28, 605/29
• US Class Current: 60/528
• CPC Class Codes: B81B 2201/032 Bimorph and unimorph actuators, e.g. piezo and thermo
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/033 Trenches
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/004 Angular deflection
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors
• 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 2001/0063 having electrostatic latches, i.e. the activated position is kept by electrostatic forces other than the activation force
• 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

Abstract

A micromechanical system can include a substrate, an actuator, and an actuated element. In particular, the actuator can include a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments. The actuated element is attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments. Related methods and actuators are also discussed.

Claims

1. A micromechanical system comprising:

a substrate;

an actuator including a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments wherein first and second actuating segments are on opposite sides of an opposing segment with a first end of the opposing segment being connected to an end of the first actuating segment, with a second end of the opposing segment being connected to an end of the second actuating segment, and with the opposing segment being free of support other than the connections at the first and second ends thereof; and

an actuated element attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments.

2. A micromechanical system according to claim 1 wherein each of the actuating segments comprises a bimorph segment including a first layer of a first material having a first coefficient of thermal expansion and a second layer of a second material having a second coefficient of thermal expansion different than the first coefficient of thermal expansion so that the actuating segments deflect in response to changes in temperature thereof.

3. A micromechanical system according to claim 1 wherein the alternating actuating and opposing segments comprise parallel beams.

4. A micromechanical system according to claim 3 wherein a second end of the serpentine arrangement rotates about an axis perpendicular to the parallel beams.

5. A micromechanical system according to claim 1 wherein the substrate includes a trench therein adjacent the serpentine arrangement.

8. A micromechanical system according to claim 1 further comprising:

a clamp that maintains a position of the actuated element relative to the substrate.

9. A micromechanical system according to claim 8 wherein the clamp comprises an electrostatic clamp.

10. A micromechanical system according to claim 1 wherein the opposing segments do not deflect significantly in response to actuation of the actuator.

11. A micromechanical system according to claim 1 wherein the actuating segments deflect in a first direction in response to actuation of the actuator and wherein the opposing segments deflect in a second direction opposite the first direction in response to actuation of the actuator.

47. A micromechanical system according to claim 1 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state, wherein spacings between the opposing segment and the first actuating segment and between the opposing segment and the second actuating segment are less than lengths of the opposing segment, the first actuating segment, and second actuating segment, and wherein each of the first actuating segment and the second actuating segment deflect along the length thereof in response to actuation.

48. A micromechanical system according to claim 1 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state and wherein the opposing segment and the first and second actuating segments are non-parallel in an actuated state.

6. A micromechanical system comprising:

a substrate;

an actuator including a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments;

an actuated element attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments; and

a second actuator including a second serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the second serpentine arrangement moves relative to the substrate upon deflection of the actuating segments wherein the second end of the second serpentine arrangement is attached to the actuated element.

7. A micromechanical system according to claim 6 further comprising:

an electrical path between the respective second ends of the first and second serpentine arrangements of the respective first and second actuators; and

a signal generator coupled between the first ends of the first and second serpentine arrangements of the respective first and second actuators so that an electrical signal generated by the signal generator actuates the actuating segments of the first and second serpentine arrangements.

12. An actuator comprising:

a serpentine arrangement of alternating actuating and opposing segments wherein the actuating segments deflect in response to actuation thereof wherein first and second actuating segments are on opposite sides of an opposing segment with a first end of the opposing segment being connected to an end of the first actuating segment, with a second end of the opposing segment being connected to an end of the second actuating segment, and with the opposing segment being free of support other than the connections at the first and second ends thereof.

13. An actuator according to claim 12 wherein each of the actuating segments comprises a bimorph segment including a first layer of a first material having a first coefficient of thermal expansion and a second layer of a second material having a second coefficient of thermal expansion different than the first coefficient of thermal expansion so that the actuating segments deflect in response to changes in temperature thereof.

14. An actuator according to claim 12 wherein the alternating actuating and opposing segments comprise parallel beams.

15. An actuator according to claim 14 wherein a first end of the serpentine arrangement is anchored to a substrate and wherein a second end of the serpentine arrangement rotates about an axis perpendicular to the parallel beams.

16. An actuator according to claim 12 further comprising:

a substrate with a first end of the serpentine arrangement anchored to the substrate wherein a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments.

17. An actuator according to claim 16 further comprising:

an actuated element attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments.

18. An actuator according to claim 16 wherein the substrate includes a trench therein adjacent the serpentine arrangement.

19. An actuator according to claim 12 wherein the actuating segments deflect in response to changes in temperature thereof.

20. An actuator according to claim 12 wherein the opposing segments do not deflect significantly in response to actuation of the actuator.

21. An actuator according to claim 12 wherein the actuating segments deflect in a first direction in response to actuation of the actuator and wherein the opposing segments deflect in a second direction opposite the first direction in response to actuation of the actuator.

49. A micromechanical system according to claim 12 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state, wherein spacings between the opposing segment and the first actuating segment and between the opposing segment and the second actuating segment are less than lengths of the opposing segment, the first actuating segment, and second actuating segment, and wherein each of the first actuating segment and the second actuating segment deflect along the length thereof in response to actuation.

50. A micromechanical system according to claim 12 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state and wherein the opposing segment and the first and second actuating segments are non-parallel in an actuated state.

22. A method of forming a micromechanical system on a substrate, the method comprising the steps of:

forming an actuator including a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments; and

forming an actuated element attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments.

23. A method according to claim 22 wherein the step of forming the actuator comprises the steps of,

forming an anchor on the substrate,

forming a sacrificial layer on the substrate,

forming the serpentine arrangement of alternating actuating and opposing segments on the sacrificial layer with the first end attached to the anchor, and

after forming the serpentine arrangement, removing the sacrificial layer.

24. A method according to claim 22 wherein each of the actuating segments comprises a bimorph segment including a first layer of a first material having a first coefficient of thermal expansion and a second layer of a second material having a second coefficient of thermal expansion different than the first coefficient of thermal expansion so that the actuating segments deflect in response to changes in temperature thereof.

25. A method according to claim 22 wherein the alternating actuating and opposing segments comprise parallel beams.

26. A method according to claim 25 wherein a second end of the serpentine arrangement rotates about an axis perpendicular to the parallel beams.

27. A method according to claim 22 further comprising the step of:

forming a trench in the substrate adjacent the serpentine arrangement.

28. A method according to claim 27 wherein the step of forming the trench follows the step of forming the actuator.

29. A method according to claim 22 further comprising the step of:

forming a second actuator including a second serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the second serpentine arrangement moves relative to the substrate upon deflection of the actuating segments wherein the second end of the second serpentine arrangement is attached to the actuated element.

30. A method according to claim 29 further comprising the step of:

forming an electrical path between the respective second ends of the first and second serpentine arrangements of the respective first and second actuators; and

forming a signal generator coupled between the first ends of the first and second serpentine arrangements of the respective first and second actuators so that an electrical signal generated by the signal generator actuates the actuating segments of the first and second serpentine arrangements.

31. A method according to claim 22 further comprising the step of:

forming a clamp that maintains a position of the actuated element relative to the substrate.

32. A method according to claim 31 wherein the clamp comprises an electrostatic clamp.

33. A method according to claim 22 wherein the opposing segments do not deflect significantly in response to actuation of the actuator.

34. A method according to claim 22 wherein the actuating segments deflect in a first direction in response to actuation of the actuator and wherein the opposing segments deflect in a second direction opposite the first direction in response to actuation of the actuator.

46. A method according to claim 22 wherein first and second actuating segments are on opposite sides of an opposing segment with a first end of the opposing segment being connected to an end of the first actuating segment, with a second end of the opposing segment being connected to an end of the second actuating segment, and with the opposing segment being free of support other than the connections at the first and second ends thereof.

53. A micromechanical system according to claim 46 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state, wherein spacings between the opposing segment and the first actuating segment and between the opposing segment and the second actuating segment are less than lengths of the opposing segment, the first actuating segment, and second actuating segment, and wherein each of the first actuating segment and the second actuating segment deflect along the length thereof in response to actuation.

54. A micromechanical system according to claim 46 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state and wherein the opposing segment and the first and second actuating segments are non-parallel in an actuated state.

35. A method of forming an actuator on a substrate, the method comprising the step of:

forming a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments wherein first and second actuating segments are on opposite sides of an opposing segment with a first end of the opposing segment being connected to an end of the first actuating segment, with a second end of the opposing segment being connected to an end of the second actuating segment, and with the opposing segment being free of support other than the connections at the first and second ends thereof.

36. A method according to claim 35 wherein the step of forming the serpentine arrangement comprises the steps of,

forming an anchor on the substrate,

forming a sacrificial layer on the substrate,

forming the serpentine arrangement of alternating actuating and opposing segments on the sacrificial layer with the first end attached to the anchor, and

after forming the serpentine arrangement, removing the sacrificial layer.

37. A method according to claim 35 wherein each of the actuating segments comprises a bimorph segment including a first layer of a first material having a first coefficient of thermal expansion and a second layer of a second material having a second coefficient of thermal expansion different than the first coefficient of thermal expansion so that the actuating segments deflect in response to changes in temperature thereof.

38. A method according to claim 35 wherein the alternating actuating and opposing segments comprise parallel beams.

39. A method according to claim 38 wherein the second end of the serpentine arrangement rotates about an axis perpendicular to the parallel beams.

43. A method according to claim 35 wherein the actuating segments deflect in response to changes in temperature thereof.

44. A method according to claim 35 wherein the opposing segments do not deflect significantly in response to actuation of the actuator.

45. A method according to claim 35 wherein the actuating segments deflect in a first direction in response to actuation of the actuator and wherein the opposing segments deflect in a second direction opposite the first direction in response to actuation of the actuator.

51. A micromechanical system according to claim 35 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state, wherein spacings between the opposing segment and the first actuating segment and between the opposing segment and the second actuating segment are less than lengths of the opposing segment, the first actuating segment, and second actuating segment, and wherein each of the first actuating segment and the second actuating segment deflect along the length thereof in response to actuation.

52. A micromechanical system according to claim 35 wherein the opposing segment and the first and second actuating segments are parallel in a non-actuated state and wherein the opposing segment and the first and second actuating segments are non-parallel in an actuated state.

40. A method of forming an actuator on a substrate, the method comprising the step of:

forming a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments wherein the alternating actuating and opposing segments comprise parallel beams; and

forming an actuated element attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments.

41. A method of forming an actuator on a substrate, the method comprising the steps of:

forming a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments; and

forming a trench therein adjacent the serpentine arrangement.

42. A method according to claim 41 wherein the step of forming the trench follows the step of forming the serpentine arrangement.