Damped micromechanical device

• US 6,787,969 B2
• Filed: 06/06/2001
• Issued: 09/07/2004
• Est. Priority Date: 06/06/2000
• Status: Expired due to Fees

• Current Assignee: Coherent Inc (Coherent Corp.)
• Original Assignee: iolon, Inc. (Coherent Corp.)
• Inventors: Yasumura, Kevin Y., Drake, Joseph D., Jerman, John H., Grade, John D.
• Primary Examiner(s): Tamai, Karl
• Application Number:
  US09/876,265
• Publication Number:
  US 20020101129A1
• Time in Patent Office: 1,189 Days
• Field of Search: 310/309, 359/223, 359/872, 359/877, 359/298, 735/041.2, 735/143.2
• US Class Current: 310/309
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

A damped micromechanical device comprising a substrate, a movable structure overlying the substrate and a flexural member having a first end portion coupled to the substrate and a second end portion coupled to the movable structure. The movable structure is movable at a resonant frequency between first and second positions relative to the substrate. A damping material is adhered to at least a portion of the flexural member for damping the movement of the movable structure at the resonant frequency. A method for making the micromechanical device is provided.

Claims

1. A damped micromechanical device comprising a substrate extending in a plane, a movable structure overlying the substrate, a flexural member having a first end portion coupled to the substrate and a second end portion coupled to the movable structure and having a side surface extending substantially perpendicular to the plane of the substrate, the movable structure being movable at a resonant frequency between first and second positions relative to the substrate, and a damping material adhered to the side surface along the first end portion of the flexural member and rigidly coupled to the substrate for damping the movement of the movable structure at the resonant frequency.

2. The device of claim 1 further comprising a first comb drive member mounted on the substrate, the movable structure including a second comb drive member, the second comb drive member being movable at the resonant frequency between first and second positions relative to the first comb drive member.

3. The device of claim 2 wherein the first comb drive member has a plurality of first comb drive fingers and the second comb drive member has a plurality of second comb drive fingers, the second comb drive fingers being not substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the first position and the second comb drive fingers being substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the second position.

4. The device of claim 1 wherein the flexural member has a top surface extending substantially parallel to the plane of the substrate, the top surface being free of damping material.

5. The device of claim 1 wherein the damping material is an elastomeric material.

6. The device of claim 5 wherein the elastomeric material is selected from the group consisting of silicon rubber, urethanes and epoxies.

7. The device of claim 1 wherein the damping material is a beryllium metal.

8. The device of claim 1 wherein the movable structure has a mechanical quality factor Q ranging from 0.3 to 20.

9. The device of claim 8 wherein the movable structure has a mechanical quality factor Q ranging from 0.5 to 3.

10. The device of claim 1 wherein the substrate has a side surface facing the first end portion of the flexural member, the damping material adhered to the side surface of the substrate.

11. The device of claim 10 wherein the side surface of the flexural member is spaced-apart from the side surface of the substrate by a space, the substrate being provided with a reservoir for receiving the damping material, the reservoir being in fluid communication with the space for permitting damping material to flow from the reservoir into the space.

12. The device of claim 11 wherein the substrate is provided with a passageway extending from the reservoir to the space for permitting damping material to flow from the reservoir into the space.

13. A damped micromechanical device comprising a substrate extending in a plane, a movable structure overlying the substrate, a flexural member having a first end portion coupled to the substrate and a second end portion coupled to the movable structure and having a side surface extending substantially perpendicular to the plane of the substrate, the movable structure being movable at a resonant frequency between first and second positions relative to the substrate, and a damping material adhered to the side surface along at least a portion of the flexural member for damping the movement of the movable structure at the resonant frequency, the flexural member having a top surface extending substantially parallel to the plane of the substrate, the top surface being free of damping material.

16. The device of claim 13 wherein the damping material is adhered to the first end portion of the flexural member.

17. The device of claim 13 wherein the damping material is an elastomeric material.

18. The device of claim 17 wherein the elastomeric material is selected from the group consisting of silicon rubber, urethanes and epoxies.

19. The device of claim 13 wherein the damping material is a beryllium metal.

20. The device of claim 13 wherein the movable structure has a mechanical quality factor Q ranging from 0.3 to 20.

21. The device of claim 20 wherein the movable structure has a mechanical quality factor Q ranging from 0.5 to 3.

22. The device of claim 13 wherein the substrate has a side surface facing the portion of the flexural member, the damping material adhered to the side surface of the substrate.

23. The device of claim 22 wherein the side surface of the flexural member is spaced-apart from the side surface of the substrate by a space, the substrate being provided with a reservoir for receiving the damping material, the reservoir being in fluid communication with the space for permitting damping material to flow from the reservoir into the space.

24. The device of claim 23 wherein the substrate is provided with a passageway extending from the reservoir to the space for permitting damping material to flow from the reservoir into the space.

14. The device of claim further comprising a first comb drive member mounted on the substrate, the movable structure including a second comb drive member, the second comb drive member being movable at the resonant frequency between first and second positions relative to the first comb drive member.

15. The device of claim 14 wherein the first comb drive member has a plurality of first comb drive fingers and the second comb drive member has a plurality of second comb drive fingers, the second comb drive fingers being not substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the first position and the second comb drive fingers being substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the second position.

25. A damped micromechanical device comprising a substrate extending in a plane, a movable structure overlying the substrate, a flexural member having a first end portion coupled to the substrate and a second end portion coupled to the movable structure and having a side surface extending substantially perpendicular to the plane of the substrate, the movable structure being movable at a resonant frequency between first and second positions relative to the substrate, and a damping material adhered to the side surface along at least a portion of the flexural member for damping the movement of the movable structure at the resonant frequency, the substrate having a side surface facing the portion of the flexural member, the damping material being adhered to the side surface of the substrate.

26. The device of claim 25 further comprising a first comb drive member mounted on the substrate, the movable structure including a second comb drive member, the second comb drive member being movable at the resonant frequency between first and second positions relative to the first comb drive member.

27. The device of claim 26 wherein the first comb drive member has a plurality of first comb drive fingers and the second comb drive member has a plurality of second comb drive fingers, the second comb drive fingers being not substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the first position and the second comb drive fingers being substantially fully interdigitated with the first comb drive fingers when the second comb drive member is in the second position.

28. The device of claim 25 wherein the damping material is adhered to the first end portion of the flexural member.

29. The device of claim 25 wherein the damping material is an elastomeric material.

30. The device of claim 29 wherein the elastomeric material is selected from the group consisting of silicon rubber, urethanes and epoxies.

31. The device of claim 25 wherein the damping material is a beryllium metal.

32. The device of claim 25 wherein the movable structure has a mechanical quality factor Q ranging from 0.3 to 20.

33. The device of claim 32 wherein the movable structure has a mechanical quality factor Q ranging from 0.5 to 3.

34. The device of claim 25 wherein the side surface of the flexural member is spaced-apart from the side surface of the substrate by a space, the substrate being provided with a reservoir for receiving the damping material, the reservoir being in fluid communication with the space for permitting damping material to flow from the reservoir into the space.

35. The device of claim 34 wherein the substrate is provided with a passageway extending from the reservoir to the space for permitting damping material to flow from the reservoir into the space.