Multistage proof-mass movement deceleration within MEMS structures

• US 8,011,247 B2
• Filed: 06/26/2008
• Issued: 09/06/2011
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Glenn, Max
• Primary Examiner(s): Wiliams; Hezron E
• Assistant Examiner(s): SHAH, SAMIR M
• Application Number:
  US12/147,354
• Publication Number:
  US 20090320592A1
• Time in Patent Office: 1,167 Days
• Field of Search: 735/041.2, 735/033, 735/041.4, 735/10, 735/141.6, 735/143.2, 735/39
• US Class Current: 73/539
• 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 first deceleration beam extending from a first side of said body, said at least one first 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; and

at least one second deceleration beam extending from a second side of said body, said at least one second deceleration beam configured to engage at least one deceleration extension extending from at least one crossbeam 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 said at least one crossbeam extending between said plurality of suspensions, said body connected to said at least one 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 at least one crossbeam.

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

the at least one crossbeam extending between said plurality of suspensions; and

an anchor attached to said at least one crossbeam and said substrate, said body connected to said at least one 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 at least one raised area 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 at least one raised area 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 of said plurality of suspensions has a serpentine configuration.

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

at least two 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

at least two 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 8, wherein said at least two deceleration beams disposed on the first side of the first and second deceleration extensions have respective first and second widths, said first width being smaller than said second width.

10. A device according to claim 9, wherein said at least two deceleration beams disposed on the second side of the first and second deceleration extensions have respective first and second widths, said first width being smaller than said second width.

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

12. 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.

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

14. 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.

15. 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 at least one proof mass;

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

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

a fifth deceleration beam extending from said body toward a crossbeam said fifth deceleration beam configured to engage at least one deceleration extension extending from at least one crossbeam and slow or stop said proof mass before said proof mass contacts said motor drive comb and said motor sense comb.

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

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

18. A deceleration stop according to claim 15 wherein said at least one deceleration extension extending from said at least one proof mass 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.

19. A device according to claim 15, wherein said first and second deceleration beams extending from said body toward said at least one proof mass have respective first and second widths, said first width being smaller than said second width.

20. A gyroscope, comprising:

a substrate;

at least one crossbeam anchored to said substrate;

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

a plurality of suspensions connected to a respective one of said at least one crossbeam and configured to suspend said at least one proof mass above said substrate;

motor drive combs adjacent said at least one proof mass;

motor sense combs adjacent said at least one proof mass;

at least one body attached to said at least one crossbeam;

first and second deceleration beams extending from said at least one body toward said at least one proof mass, the 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 at least one proof mass in a first direction;

third and fourth deceleration beams extending from said at least one body toward said at least one proof mass, the 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 at least one proof mass in a second direction, said first and second deceleration extensions configured to engage at least one of said first, second, third, or fourth deceleration beams and cause said at least one proof mass to slow or stop before contacting said motor drive combs and said motor sense combs; and

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