MULTISTAGE PROOF-MASS MOVEMENT DECELERATION WITHIN MEMS STRUCTURES

• US 20090320592A1
• Filed: 06/26/2008
• Published: 12/31/2009
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Glenn, Max
• Granted Patent: US 8,011,247 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: B81B 2201/0235 Accelerometers
• 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 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A micro-electromechanical systems (MEMS) device includes a substrate comprising at least one anchor, a proof mass having first and second deceleration extensions extending therefrom, a motor drive comb, a motor sense comb, a plurality of suspensions configured to suspend the proof mass over the substrate and between the motor drive comb and the motor sense comb. The suspensions are anchored to the substrate. A body is attached to the substrate. At least one deceleration beam extends from a first side of said body. The at least one deceleration beam is configured to engage at least one of the first and second deceleration extensions and slow or stop the proof mass before the proof mass contacts the motor drive comb and the motor sense comb.

Claims

1. A micro-electromechanical systems (MEMS) device comprising:

a substrate comprising at least one anchor;

a proof mass comprising first and second deceleration extensions extending from said proof mass;

a motor drive comb;

a motor sense comb;

a plurality of suspensions configured to suspend said proof mass over said substrate and between said motor drive comb and said motor sense comb, said suspensions anchored to said substrate;

a body attached to said substrate; and

at least one deceleration beam extending from a first side of said body, said at least one deceleration beam configured to engage at least one of said first and second deceleration extensions and slow or stop said proof mass before said proof mass contacts said motor drive comb and said motor sense comb.

2. A device according to claim 1 wherein said device further comprises at least one crossbeam extending between said suspensions, said body connected to said crossbeam and attached to said substrate.

3. A device according to claim 2 wherein said device further comprises an anchoring extension which is utilized to connect said body to said crossbeam.

4. A device according to claim 1 wherein said device further comprises:

at least one crossbeam extending between said suspensions; and

an anchor attached to said crossbeam and said substrate, said body connected to said crossbeam.

5. A device according to claim 1 wherein at least one of said first and second deceleration extensions comprises:

a bottom surface; and

at least one raised area on said bottom surface, said raised areas configured to reduce or eliminate contact between said proof mass and components of said device under said proof mass.

6. A device according to claim 1 wherein at least one of said first and second deceleration extensions comprises:

a top surface; and

at least one raised area on said top surface, said raised areas configured to reduce or eliminate contact between said proof mass and components of said device above said proof mass.

7. A device according to claim 1 wherein each said suspension of the plurality has a serpentine configuration.

8. A device according to claim 1 wherein said at least one deceleration beam comprises:

first and second deceleration beams disposed on a first side of the first and second deceleration extensions and configured to slow or stop motion of said proof mass in a first direction; and

third and fourth deceleration beams disposed on a second side of the first and second deceleration extensions and configured to slow or stop motion of said proof mass in a second direction.

9. A device according to claim 1 wherein said deceleration extensions and said at least one deceleration beam are configured to bend when engaged and provide the deceleration function for said proof mass.

10. A device according to claim 1 wherein:

said first and second deceleration extensions have respective first and second widths; and

said first width is smaller than said second width.

11. A device according to claim 1, wherein said proof mass further comprises a third deceleration extension.

12. A device according to claim 2, further comprising:

at least one deceleration beam extending from a second side of said body; and

a third deceleration extension extending from said crossbeam, said at least one deceleration beam extending from the second side of the body configured to engage the third deceleration extension and slow or stop said proof mass before said proof mass contacts said motor drive comb and said motor sense comb.

13. A device according to claim 1 wherein said device comprises at least one of a gyroscope, an inertial measurement unit, an accelerometer, a pressure sensor, and a temperature sensor.

14. A deceleration stop for a micro-electromechanical systems (MEMS) device, the MEMS device comprising a substrate and at least one proof mass, said deceleration stop comprising:

a body;

at least one deceleration extension extending from said proof mass;

first and second deceleration beams extending from said body toward said proof mass, disposed on a first side of the deceleration extension and configured to slow or stop motion of said proof mass in a first direction; and

third and fourth deceleration beams extending from said body toward said proof mass, disposed on a second side of the deceleration extension and configured to slow or stop motion of said proof mass in a second direction, said deceleration extension configured to engage at least one of said deceleration beams and cause the grid proof mass to slow or stop before contacting components of the MEMS device adjacent to said proof mass.

15. A deceleration stop according to claim 14 wherein said body is anchored to the substrate.

16. A deceleration stop according to claim 15 further comprising an anchoring extension which is utilized to connect said body to a crossbeam of the MEMS device.

17. A deceleration stop according to claim 14 wherein said at least one deceleration extension comprises first, second and third deceleration extensions having respective first, second and third widths, wherein said first and second widths are smaller than said third width.

18. A gyroscope, comprising:

a substrate;

at least one crossbeam anchored to said substrate;

at least one proof mass, each said proof mass comprising first and second deceleration extensions;

a plurality of suspensions connected to a respective one of said crossbeams and configured to suspend said proof masses above said substrate;

motor drive combs adjacent each said proof mass;

motor sense combs adjacent each said proof mass;

at least one body attached to each said crossbeam;

first and second deceleration beams extending from said at least one body, disposed on a first side of the first and second deceleration extensions and configured to slow or stop motion of said proof mass in a first direction; and

third and fourth deceleration beams extending from said at least one body, disposed on a second side of the first and second deceleration extensions and configured to slow or stop motion of said proof mass in a second direction, said deceleration extensions configured to engage at least one of said deceleration beams and cause said proof masses to slow or stop before contacting said motor drive comb and said motor sense comb.