CONFIGURATION TO REDUCE NON-LINEAR MOTION

• US 20160363445A1
• Filed: 09/24/2014
• Published: 12/15/2016
• Est. Priority Date: 01/21/2014
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: ANAC, Ozan, SEEGER, Joseph
• Granted Patent: US 9,958,271 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2203/0163 Spring holders
• 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: G01C 19/5733 Structural details or topology
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01P 15/0802 Details

Abstract

Embodiments for modifying a spring mass configuration are disclosed that minimize the effects of unwanted nonlinear motion on a MEMS sensor. The modifications include any or any combination of providing a rigid element between rotating structures of the spring mass configuration, tuning a spring system between the rotating structures and coupling an electrical cancellation system to the rotating structures. In so doing unwanted nonlinear motion such as unwanted 2nd harmonic motion is minimized

Claims

1. A MEMS sensor comprising;

a first and second rotating arms, wherein the first and second rotating arms are coupled to each other and the first and second rotating arms are configured to counter rotate when driven into oscillation;

at least one travelling system, where in the at least one travelling system is coupled to the first and second rotating arms;

at least one actuator for driving the at least one travelling system into oscillation;

wherein the at least one travelling system moves in a first direction when driven into oscillation.

2. The MEMS sensor of claim 1 further includes a substrate.

3. The MEMS sensor of claim 2, wherein the travelling system moves in a plane parallel to the substrate.

4. The MEMS sensor of claim 2, wherein the first and second rotating arms are coupled to an anchor on the substrate by a set of flexible elements.

5. The MEMS sensor of claim 1, wherein the at least one travelling system comprises at least one traveling mass and at least one flexible element.

6. The MEMS sensor of claim 1, further including at least one transducer for sensing motion of a portion of the at least one travelling system.

7. The MEMS sensor of claim 6, wherein the at least one transducer can be any of a capacitive transducer, an optical transducer or a piezoelectric transducer.

8. The MEMS sensor of claim 6, wherein the at least one transducer senses motion of a portion of the travelling system in a second direction which is in plane and orthogonal to the first direction.

9. The MEMS sensor of claim 8, wherein the at least one travelling system is coupled to the first rotating arm by a first flexible element and the travelling system is coupled to the second rotating arm by a second flexible element.

10. The MEMS sensor of claim 8, wherein the at least one travelling system includes at least one travelling mass and at least one proof mass coupled to each other;

wherein the at least one travelling mass and the at least one proof mass move in the first direction when driven into oscillation.

11. The MEMS sensor of claim 10, wherein the at least one proof mass rotates less than the rotating arm.

12. The MEMS sensor of claim 9, wherein the first and second flexible elements are compliant to in plane rotation.

13. The MEMS sensor of claim 9, wherein the travelling system comprises a travelling mass and the travelling mass is coupled to the first and second flexible elements.

14. The MEMS sensor of claim 5, wherein at least one proof mass is flexibly coupled to the travelling mass and can move relative to the travelling mass in the second direction.

15. The MEMS sensors of claim 13, wherein the first and second rotating arms are disposed symmetrically with respect to the travelling system.

16. The MEMS sensors of claim 14, wherein the first and second rotating arms are disposed symmetrically with respect to the travelling system.

17. The MEMS sensors of claim 13, wherein the first and second flexible elements have equal compliance.

18. The MEMS sensors of claim 14, wherein the first and second flexible elements have equal compliance.

19. The MEMS sensor of claim 13, wherein a first transducer senses motion of a portion of the travelling mass in the second direction.

20. The MEMS sensor of claim 14, wherein the first transducer senses motion of a portion of the at least one proof mass in the second direction.

21. The MEMS sensor of claim 1, wherein the travelling system comprises a first travelling mass and a second travelling mass;

wherein the first travelling mass is coupled to the first rotating arm by the first flexible element and the second travelling mass is coupled to the second rotating arm by the second flexible element;

wherein first and second travelling masses are coupled to each other with a third flexible element.

22. The MEMS sensor of claim 19, wherein the first travelling mass is flexibly coupled to at least one proof mass, and the at least one proof mass is able to move in the second direction relative to the travelling mass.

23. The MEMS sensor of claim 19, wherein the first travelling mass is flexibly coupled to at least one first proof mass, wherein the second travelling mass is flexibly coupled to at least one second proof mass;

at least one first proof mass and at least one second proof mass are able to move in the second direction relative to the first travelling mass and the second travelling mass, respectively.

24. The MEMS sensors of claim 21, wherein the third flexible element is compliant in the second direction.

25. The MEMS sensors of claim 21, wherein the third flexible element is a folded spring.

26. The MEMS sensors of claim 21, wherein the third flexible element comprises both a folded spring and a straight beam.

27. The MEMS sensors of claim 21, wherein the first, second and third flexible elements have unequal compliances.

28. The MEMS sensor of claim 21, wherein the first and second flexible element have the same compliance, but the third flexible element has a different compliance.

29. The MEMS sensor of claim 21, wherein the first, second and third flexible elements have equal compliances.

30. The MEMS sensor of claim 19, wherein a transducer senses motion of a portion of the first travelling mass in the second direction.

31. The MEMS sensor of claim 19, wherein a first transducer senses motion of a portion of the first travelling mass in the second direction and a second transducer senses motion of a portion of the second travelling mass in the second direction.

32. The MEMS sensor of claim 19, wherein a first transducer senses motion of a portion of the at least one proof mass in the second direction.

33. The MEMS sensor of claim 19, wherein a first transducer senses motion of a portion of the at least one first proof mass in the second direction, wherein a second transducer senses motion of a portion of the at least one second proof mass in the second direction.

34. The MEMS sensor of claim 10 including at least one transducer for detecting motion of at least a portion of the at least one traveling mass in response to angular velocity.

35. The MEMS sensor of claim 10 including at least one transducer for detecting motion of at least a portion of the at least one proof mass in response to angular velocity.