MEMS actuators with combined force and bi-directional rotation

• US 8,729,770 B1
• Filed: 05/17/2010
• Issued: 05/20/2014
• Est. Priority Date: 12/02/2003
• Status: Active Grant

• Current Assignee: Adriatic Research Institute
• Original Assignee: Adriatic Research Institute
• Inventors: Milanovic, Veljko
• Primary Examiner(s): KENERLY, TERRANCE L
• Application Number:
  US12/781,766
• Time in Patent Office: 1,464 Days
• Field of Search: 310/309, 310/40.MM, 310/310, 310/308
• US Class Current: 310/309
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/0062 Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors

Abstract

A MEMS system comprises a first rotational actuator having a first drive mechanism configured to drive rotation of a first rotator about a first axis, a second rotational actuator having a second drive mechanism configured to drive rotation of a second rotator about a second axis, first and second flexible linkages, a first drive beam coupled to the first rotator and to the first flexible linkage, a second drive beam coupled to the second rotator and to the second flexible linkage, and one or more device mounts coupled to the first and second flexible linkages. The one or more device mounts are configured to provide distributed points of attachment of a device. The rotation of the first and second rotators causes the device mount to rotate or piston.

Claims

1. A MEMS system, comprising:

a first rotational actuator having a first drive mechanism configured to drive rotation of a first rotator about a first axis;

a second rotational actuator having a second drive mechanism configured to drive rotation of a second rotator about a second axis that is not perpendicular to the first axis;

a first flexible linkage;

a first linking beam coupled to the first rotator and to the flexible linkage;

a second linking beam coupled to the second rotator and to the first flexible linkage on a first side of the second rotator;

a drive beam coupled to the second rotator on a second side of the second rotator opposite the first side;

a second flexible linkage coupled to the drive beam;

a device mount coupled to the second flexible linkage, wherein the second flexible linkage is disposed between the drive beam and the device mount,

wherein the first and second rotational actuators, first and second flexible linkages and first, and second, linking beams and the drive beam are configured to rotate the device mount about a device rotation axis when the first and second rotators rotate about the first and second axes, and

wherein the first and second rotators, first and second flexible linkages, first and second linking beams and the drive beam are on a common side of the device rotation axis.

2. The system of claim 1 wherein the first and second rotational actuators are bi-directional actuators.

3. The system of claim 1 wherein the first and second rotators are configured to rotate in opposite senses of rotation about the first and second axes respectively.

4. The system of claim 1 further comprising a flexure beam coupled between the device mount and an anchor point wherein the flexure beam is configured to restrict undesired movement of the device mount or restrict undesired rotation of the device mount about an axis other than the device rotation axis.

5. The system of claim 4 wherein the flexure beam coupled between the device mount and the anchor point has a relatively stiff portion along most of its length and a relatively flexible portion close to the anchor point.

6. The system of claim 1 further comprising a third rotational actuator having a third drive mechanism configured to drive rotation of a third rotator about a third axis;

a fourth rotational actuator having a fourth drive mechanism configured to drive rotation of a fourth rotator about a fourth axis that is not perpendicular to the third axis, a flexible linkage;

a third linking beam coupled to the first rotator and to the flexible linkage;

a second linking beam coupled to the second rotator and to the flexible linkage, a second drive beam coupled to the third or fourth rotator, a second flexible linkage coupled to the drive beam and the device mount, whereby rotation of the third and/or fourth actuator causes the second drive beam and second flexible linkage to rotate the device mount about a second device rotation axis that is different from the device rotation axis.

7. The system of claim 1 wherein one or more of the first or second actuators include one or more combdrives.

8. The system of claim 1 wherein one or more of the first or second actuators include one or more balanced rotators comprised of opposing down-force and up-force vertical combdrives on either side of a rotating axis.

9. The system of claim 1 wherein one or more of the first or second actuators include one or more un-balanced uni-directional rotators comprised of either a down-force or an up-force vertical combdrive on either side or on both sides of a rotating axis.

10. The system of claim 1 wherein one or more of the first or second actuators include one or more balanced bi-directional rotators comprised of opposing down-force and up-force vertical combdrives on either side of the central rotating axis, respectively.

11. The system of claim 1 wherein one or more of the first and second actuators includes one or more sets of rotator comb fingers attached to the rotator and one or more sets of fixed comb fingers that interdigitate with the comb fingers.

12. The system of claim 11 wherein the rotator comb fingers include first and second subsets of fingers that are at different levels on the same side of the axis and wherein the fixed comb fingers include first and second subsets of fingers that are at different levels on the same side of the axis.

13. The system of claim 1, wherein one or more of the first and second flexible linkages is a bi-axial linkage including a first flexure beam configured to flex about a first flexure axis, a second flexure beam attached to the first flexure beam, wherein the second flexure beam is configured to flex about a second flexure axis, wherein the second flexure axis is non-parallel to the first flexure axis, the bi-axial linkage further having a third flexure beam attached to the second flexure beam in a spaced-apart substantially parallel relationship to the second flexure beam, wherein the third flexure beam is configured to flex about a third flexure axis that is substantially parallel to the second flexure axis.

14. The system of claim 13 wherein the first flexure axis is substantially perpendicular to the second and third flexure axes.

15. The system of claim 13 wherein the biaxial linkage is mechanically coupled to the device mount.

16. The system of claim 13 wherein the first second and third flexure beams are characterized by substantially different coefficients of torsional stiffness.

17. The system of claim 16 wherein the biaxial linkage is mechanically coupled to the device mount by a beam attached at a first end to the third flexure beam and attached at a second end to the device mount.

18. A MEMS system, comprising:

a first rotational actuator having a first drive mechanism configured to drive rotation of a first rotator about a first axis;

a second rotational actuator having a second drive mechanism configured to drive rotation of a second rotator about a second axis that is not perpendicular to the first axis;

a flexible linkage;

a first linking beam coupled to the first rotator and to the flexible linkage;

a second linking beam coupled to the second rotator and to the flexible linkage;

a drive beam coupled to the first or second rotator; and

a flexible linkage coupled to the drive beam and a device mount coupled to the flexible linkage, whereby rotation of the first and/or second actuator causes the drive beam and linkage to rotate the device mount about a device rotation axis,

wherein one or more of the flexible linkages is a bi-axial linkage including a first flexure beam configured to flex about a first flexure axis, a second flexure beam attached to the first flexure beam, wherein the second flexure beam is configured to flex about a second flexure axis, wherein the second flexure axis is non-parallel to the first flexure axis, the bi-axial linkage further having a third flexure beam attached to the second flexure beam in a spaced-apart substantially parallel relationship to the second flexure beam, wherein the third flexure beam is configured to flex about a third flexure axis that is substantially parallel to the second flexure axis.

19. The system of claim 18 wherein the first flexure axis is substantially perpendicular to the second and third flexure axes.

20. The system of claim 18 wherein the biaxial linkage is mechanically coupled to the device mount.

21. The system of claim 18 wherein the first second and third flexure beams are characterized by substantially different coefficients of torsional stiffness.

22. The system of claim 21 wherein the biaxial linkage is mechanically coupled to the device mount by a beam attached at a first end to the third flexure beam and attached at a second end to the device mount.

23. A combdrive actuator, comprising:

a rotator coupled to an anchor point by a flexible member that permits rotation of the rotator about an axis while providing a restoring force;

one or more sets of rotator comb fingers attached to the rotator; and

one or more sets of fixed comb fingers that interdigitate with the comb fingers, wherein the fixed comb fingers are fixed with respect to the anchor point,

wherein the rotator comb fingers include first and second subsets of fingers that are at different levels on the same side of the axis and wherein the fixed comb fingers include first and second subsets of fingers that are at different levels on the same side of the axis.

24. A MEMS system, comprising:

a first rotational actuator having a first drive mechanism configured to drive rotation of a first rotator about a first axis;

a second rotational actuator having a second drive mechanism configured to drive rotation of a second rotator about a second axis;

first and second flexible linkages;

a first drive beam coupled to the first rotator and to the first flexible linkage;

a second drive beam coupled to the second rotator and to the second flexible linkage; and

one or more device mounts coupled to the first and second flexible linkages, whereby rotation of the first and second rotators causes the device mount to rotate or piston, wherein the one or more device mounts are configured to provide distributed points of attachment of a device.

25. The system of claim 24 wherein the one or more device mounts include first and second spaced-apart device mounts.

26. The system of claim 25 wherein the first device mount is coupled to the first flexible linkage and wherein the second device mount is coupled to the second flexible linkage and wherein a device is mounted to the first and second device mounts.

27. The system of claim 25 wherein the first and second device mounts are attached to a common support, wherein the common support is coupled to the first and second flexible linkages.

28. The system of claim 24 wherein the first and/or second flexible linkage includes stiff beam having first and second ends and a flexure beam mounted at both ends to the stiff beam.

29. The system of claim 24 wherein the first axis is not perpendicular to the second axis.

30. The system of claim 24 wherein the second axis is perpendicular to the first axis.