MICRO-ELECTRO-MECHANICAL DEVICE WITH COMPENSATION OF ERRORS DUE TO DISTURBANCE FORCES, SUCH AS QUADRATURE COMPONENTS

• US 20170268880A1
• Filed: 05/31/2017
• Published: 09/21/2017
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Falorni, Luca Giuseppe, Valzasina, Carlo, Carminati, Roberto, Tocchio, Alessandro
• Granted Patent: US 10,113,872 B2
• Time in Patent Office: Days
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 2203/0163 Spring holders
• CPC Class Codes: B81B 3/0018 Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• 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

Abstract

MEMS device having a support region elastically carrying a suspended mass through first elastic elements. A tuned dynamic absorber is elastically coupled to the suspended mass and configured to dampen quadrature forces acting on the suspended mass at the natural oscillation frequency of the dynamic absorber. The tuned dynamic absorber is formed by a damping mass coupled to the suspended mass through second elastic elements. In an embodiment, the suspended mass and the damping mass are formed in a same structural layer, for example of semiconductor material, and the damping mass is surrounded by the suspended mass.

Claims

1. A MEMS device comprising:

a substrate;

elastic elements;

a drive system; and

a plurality of movable mass systems elastically coupled to the substrate and the drive system by the elastic elements, the plurality of movable mass systems being configured to be driven by the drive system, each of the plurality of movable mass systems including;

a suspended mass configured to be subjected to disturbance forces; and

a damping mass configured to resonate at its natural frequency in response to the respective suspended mass systems being driven by the drive system, the damping mass being configured to reduce movements of the suspended mass due to the disturbance forces.

2. The MEMS device of claim 1, wherein the damping masses are located in openings of the suspended masses and elastically coupled to the suspended masses by springs.

3. The MEMS device of claim 2, wherein the springs have a first elastic constant and the elastic elements have a second elastic constant that is different from the first elastic constant.

4. The MEMS device of claim 1, wherein the plurality of movable mass systems includes first and second pairs of movable mass systems, the first pair of movable mass systems being arranged relative to a first axis, the second pair of movable mass systems being arranged relative to a second axis, the second axis being transverse to the first axis.

6. The MEMS device of claim 1, wherein each of the plurality of movable mass systems have a trapexoidal shape.

7. The MEMS device of claim 1, wherein the damping masses are configured to absorb quadrature forces acting on the movable mass systems, respectively, in response to the MEMS device being rotated.

8. The MEMS device of claim 1, wherein each of the suspended masses and the damping masses are formed in a same structural layer.

9. The MEMS device of claim 8, wherein the structural layer is a semiconductor material.

10. The MEMS device of claim 8, wherein the drive system drives the plurality of movable mass systems relative to a central axis.

5. The MEMS device of 4, wherein the drive system is configured to drive the first pair of movable mass systems in a first direction that corresponds to the first axis, wherein the drive system is configured to drive the second pair of movable mass systems in a second direction that corresponds to the second axis.

11. An electronic device comprising:

a controller; and

a MEMS device coupled to the controller, the MEMS device including;

elastic elements;

a drive system; and

first and second movable mass systems elastically coupled to the drive system by the elastic elements and configured to be driven by the drive system, the first movable mass system including a first suspended mass and a first damping mass, the second movable mass including a second suspended mass and a second damping mass, the first and second suspended masses configured to be subjected to quadrature forces, the first and second damping masses configured to resonate at their natural frequency in response to being driven by the drive system, the first and second damping masses being configured to reduce movements of the first and second suspended masses, respectively, due to the quadrature forces.

12. The electronic device according to claim 11, wherein the first and second damping masses are located in openings of the first and second suspended masses, respectively.

13. The electronic device according to claim 11, wherein the drive assembly is configured to drive the first and second movable mass systems in a first plane, wherein the quadrature forces are perpendicular to the first plane.

14. The electronic device according to claim 13, wherein first and second movable mass systems are aligned relative to each other along a first axis, wherein the drive assembly drives the first and second movable mass systems in a direction that is parallel to the first axis.

15. The electronic device according to claim 11, wherein the MEMS device is a gyroscope.

16. The electronic device according to claim 11, wherein the electronic device is at least one of a tablet, a laptop, a portable computer, a smartphone, a wearable device, a messaging device, a digital music player, and a digital photo or video camera.

17. A gyroscope comprising:

a substrate;

a central anchor;

a drive system;

first and second elastic elements; and

a plurality of movable mass systems elastically coupled to the central anchor by the first elastic elements and coupled to the drive system by the second elastic elements, each of the plurality of movable mass systems including;

a suspended mass configured to be subjected to quadrature forces; and

a damping mass configured to resonate at its natural frequency in response to being driven by the drive system, the damping mass being configured to reduce movements of the suspended mass due to the quadrature forces.

18. The gyroscope of claim 17, wherein the damping masses of the plurality of movable mass systems are located in openings of the suspended masses, respectively.

19. The gyroscope of claim 17, wherein the plurality of movable mass systems are arranged to surround the central anchor.

20. The gyroscope of claim 19, wherein each of the plurality of movable mass systems have a trapexoidal shape.