SYSTEMS AND METHODS FOR AN INERTIAL SENSOR SUSPENSION THAT MINIMIZES PROOF MASS ROTATION

• US 20100147073A1
• Filed: 12/16/2008
• Published: 06/17/2010
• Est. Priority Date: 12/16/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Johnson, Burgess R., Engel, Jonathan M.
• Granted Patent: US 8,146,424 B2
• Time in Patent Office: Days
• US Class Current: 73/504.160
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

The present invention generally relates to systems and methods for an inertial sensor suspension that minimizes proof mass rotation and translation. The system contains a microelectromechanical sensor (MEMS) device for measuring rotation along an input rotation axis. The MEMS device includes at least one substrate, at least one proof mass, and a suspension system. The suspension system includes at least one flexure connecting the at least one proof mass to a substrate and at least one anchored suspension element with a split support beam having a first split portion and a second split portion. The first split portion and the second split portion are of curved shape.

Claims

1. A microelectromechanical system (MEMS) device for measuring rotation along an input rotation axis, the device comprising:

a substrate;

at least one proof mass; and

a suspension system comprising;

at least two crossbars;

at least one flexure connecting the at least one proof mass to one of the crossbars; and

at least two anchored suspension elements comprising a split support beam having a first split portion and a second split portion, wherein the at least two anchored suspension elements are connected between the at least two crossbars and substrate anchors,

wherein first ends of the first split portion and the second split portion are separated by a first width and second ends of the first split portion and the second split portion are separated by a second width, the first width being smaller than the second width.

2. The device of claim 1, wherein the at least two anchored suspension elements are configured to resist rotational movement of the at least one proof mass around the input rotation axis in response to a differential force and resist translational movement due to a common mode input force.

3. The device of claim 1, wherein the anchored suspension element further comprises an anchor connecting the first split portion to the second split portion and wherein the first and second split portions are curved.

4. The device of claim 3, wherein the anchored suspension element is substantially a wishbone shape.

5. The device of claim 1, wherein the at least two crossbars comprise a thinned crossbar connecting the first split portion to the second split portion.

6. The device of claim 1, wherein the at least one flexure is configured to resist rotational movement of the at least one proof mass around the input rotation axis in response to a differential force.

7. The device of claim 6, wherein the at least one flexure is substantially a hairpin spring shape.

8. The device of claim 7, wherein at least two flexures are configured to be different in at least one of thickness, length, width, density, shape, or material in order to resist rotational movement of the at least one proof mass around the input rotation axis in response to a differential force.

9. A suspension element for a microelectromechanical sensor (MEMS) device, the suspension element comprising:

a split support beam having a first split portion and a second split portion, wherein the first split portion and a second split portion are configured to resist translation along a sense axis;

a thinned crossbar connecting the first split portion to the second split portion; and

an anchor connecting the first split portion and the second split portion, wherein the split support beam is further configured to resist a rotational movement about an input rotation axis,

wherein ends of the first split portion and the second split portion connected to the anchor are separated by a first width and ends of the first split portion and the second split portion not connected to the anchor are separated by a second width, the first width being smaller than the second width.

10. The suspension element of claim 9, wherein the first split portion and the second split portion are curved.

11. The suspension element of claim 10, wherein the first split portion and the second split portion are substantially a wishbone shape.

12. The suspension element of claim 9, wherein the anchor of the suspension element is connected to a substrate portion of the MEMS device.

13. A microelectromechanical sensor (MEMS) device comprising:

a substrate;

two crossbars coupled to the substrate;

two proof masses;

a plurality of suspension elements configured to connect the two proof masses to the two crossbars,

wherein at least two of the plurality of suspension elements are configured to be different in at least one of thickness, length, width, density, shape, or material in order to resist rotational movement of the at least one proof mass around the input rotation axis in response to a differential force or resist translational movement due to a common mode input force.

14. The suspension element of claim 13, wherein each of the plurality of suspension elements comprises:

a first elongate portion;

a second elongate portion;

a first crossbar portion;

a second crossbar portion; and

a crossbar connecting portion.

15. The suspension element of claim 14, wherein the suspension element is substantially a hairpin spring shape.

16. The suspension element of claim 13, wherein the first elongate portion of the suspension element is connected to one of the crossbars.

17. The suspension element of claim 13, wherein the second elongate portion of the suspension element is connected to a proof mass of the MEMS device.

18. The suspension element of claim 13, wherein the crossbar connecting portion is thicker than the first elongate portion, the second elongate portion, the first crossbar portion, and the second crossbar portion.