Flexible vibratory micro-electromechanical device

• US 6,843,127 B1
• Filed: 07/30/2003
• Issued: 01/18/2005
• Est. Priority Date: 07/30/2003
• Status: Expired due to Fees

• Current Assignee: Temic Automotive of North America, Incorporated (Continental AG)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Chiou, Jen-Huang Albert
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US10/630,044
• Publication Number:
  US 20050024527A1
• Time in Patent Office: 538 Days
• Field of Search: 735/040.4, 735/041.2, 735/041.4, 735/041.5, 735/040.2
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

There is a sensor element (24) for an electronic sensor device (20). The sensor element (24) may have a substrate (43), a pair of proof masses (34a, 34b), a set of drive beams (44), and at least one base beam (46). The pair of proof masses (34a, 34b) are suspended above the substrate (43) and attached to the substrate (43) at fixed anchor points (50). The set of drive beams (44) are positioned between the proof masses (34a, 34b) and the anchor points (50). Each drive beam (44) has a first longitudinal body portion (62) that extends in a first direction and a first flexible spring member (64) that extends along a second direction. The base beam (46) interconnects the set of drive beams (44) and has a second longitudinal body portion (72) and a second flexible spring member (74). The second longitudinal body portion (72) extends along the second direction and the second flexible spring member (74) extends along the first direction. The first and second flexible spring members (64, 74) may be serpentine in shape, such as folded beam-columns or wrinkle springs.

Claims

1. A sensor element for a sensor device, the sensor element comprising:

a substrate;

a pair of proof masses that are attached to the substrate at fixed anchor points, the pair of proof masses suspended above the substrate; and

a set of drive beams positioned between the proof masses and the anchor points, the drive beams having a first body portion that includes a first flexible spring member that extends along a first direction and a second body portion that includes a flexible spring member that extends along a second direction, the second direction being perpendicular to the first direction the first and second flexible members being configured such that a drive frequency and a sense frequency of the proof masses are substantially aligned.

2. The sensor element of claim 1 further comprising at least one base beam that interconnects the set of drive beams the base beam having a first longitudinal body portion, that includes a first flexible spring member that extends along the second direction and a second body portion that includes a second flexible spring member that extends along the first direction.

3. The sensor element of claim 1, wherein the flexible spring members are serpentine in shape.

4. The sensor element of claim 1, wherein the substrate is made of glass and the proof masses and drive beams are made of silicon.

5. The sensor element of claim 1, wherein the sensor element is used in sensing an externally induced angular rate in a gyroscope.

6. The sensor element of claim 1 further comprising a first pair of electrode combs that drives the proof masses in a first direction of a first plane at the drive frequency.

7. The sensor element of claim 6 further comprising a second pair of electrode combs and a pair of out-of-plane electrodes, the second pair of electrode combs capable of sensing the movement of the proof masses in the first plane, the pair of out-of-plane electrodes capable of sensing the movement at the sense frequency of the proof masses in a second plane, the second plane being different from the first plane.

8. A sensor element for a sensor device, the sensor element comprising:

a substrate;

a pair of proof masses that are attached to the substrate at fixed anchor points, the pair of proof masses suspended above the substrate; and

a set of drive beams positioned between the proof masses and the anchor points, each drive beam having a first body portion that extends along a first direction in a plane and a first flexible spring member therein and a second body portion that includes a second flexible spring member that extends along a second direction, the second direction in the plane being perpendicular to the fist direction, the first and second flexible spring members being configured such that a drive frequency of the proof masses in the first direction of the plane and a sense frequency of the proof masses out of the plane are substantially aligned and not aligned with at least one vibrational frequency that is in the second direction in the plane.

9. The sensor element of claim 8, wherein the flexible spring members of the drive beams are serpentine in shape.

10. The sensor element of claim 8, wherein the substrate is made of glass and the proof masses, and drive beams are made of silicon.

11. The sensor element of claim 8, wherein the sensor element is used in sensing an externally induced angular rate in a gyroscope.

12. The sensor element of claim 8 further comprising a first pair of electrode combs that drives the proof masses in a first direction of a first plane at the drive frequency.

13. The sensor element of claim 12 further comprising a second pair of electrode combs and a pair of out-of-plane electrodes, the second pair of electrode combs capable of sensing the movement of the proof masses in the first plane, the pair of out-of-plane electrodes capable of sensing the movement at the sense frequency of the proof masses in a second plane, the second plane being different from the first plane.

14. An electronic sensor comprising:

a digital processing unit; and

a sensor element, the sensor element comprising;

a substrate;

a pair of proof masses that are attached to the substrate at fixed anchor points, the pair of proof masses suspended above the substrate;

a set of drive beams positioned between the proof masses and the anchor points, each drive beam having a first longitudinal body portion that extends along a first direction in a plane and a first flexible spring member therein and a second body portion that includes a second flexible spring member that extends along a second direction in the plane, the second direction being perpendicular to the first direction, the first and second flexible spring members being configured such that a drive frequency of the proof masses in the first direction of the plane and a sense frequency of the proof masses out of the plane are substantially aligned and not aligned with at least one vibrational frequency that is in the second direction in the plane; and

at least one base beam that interconnects the set of drive beams, the base beam having a second longitudinal body portion that includes a first flexible spring member that extends along the second direction and a second body portion includes a second flexible spring member that extends along the first direction.

15. The electronic sensor of claim 14, wherein the flexible spring members of the drive beams are serpentine in shape.

16. The electronic sensor of claim 14, wherein the substrate is made of glass and the proof masses, drive beams, and base beam are made of silicon.

17. The electronic sensor of claim 14, wherein the sensor element is used in sensing an externally induced angular rate in a gyroscope.

18. The electronic sensor of claim 14, wherein the sensor element further comprises a first pair of electrode combs that drives the proof masses in a first direction of a first plane at the drive frequency, the first pair of electrode combs receiving a signal from the digital processing unit.

19. The electronic sensor of claim 18, wherein the sensor element further comprises a second pair of electrode combs and a pair of out-of-plane electrodes, the second pair of electrode combs capable of sensing the movement of the proof masses in the first plane, the pair of out-of-plane electrodes capable of sensing the movement at the sense frequency of the proof masses in a second plane, the second plane being different from the first plane, the second pair of electrode combs and the pair of out-of-plane electrodes further capable of sending signals to the digital processing unit.