Vibrating micro-mechanical sensor of angular velocity

• US 8,176,779 B2
• Filed: 04/15/2009
• Issued: 05/15/2012
• Est. Priority Date: 04/16/2008
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: VTI Technologies Oy (Murata Manufacturing Co Limited)
• Inventors: Blomqvist, Anssi
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US12/385,655
• Publication Number:
  US 20090260437A1
• Time in Patent Office: 1,126 Days
• Field of Search: 735/040.2, 735/040.3, 735/040.4, 735/040.8, 735/041.2, 735/041.3, 735/041.4, 735/041.8
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames

Abstract

Embodiments of the invention relate to measuring devices used in measuring angular velocity and, more precisely, to vibrating micro-mechanical sensors of angular velocity. The sensor of angular velocity according to an embodiment of the invention is adapted to measure angular velocity in relation to two or three axes, and at the least two seismic masses (34-36, 52-53, 71-75) of the sensor of angular velocity are adapted to be activated into primary motion vibration by a common mode. The structure of the sensor of angular velocity according to the invention enables reliable measuring with good performance, particularly in small size vibrating micro-mechanical sensors of angular velocity.

Claims

1. A vibrating micro-mechanical sensor of angular velocity, comprising:

at least two seismic masses suspended by support structures and/or spring structures; and

spring structures coupling said at least two seismic masses to each other,

wherein the sensor of angular velocity is configured to measure angular velocity in relation to two or three axes by means of electrodes of said at least two seismic masses and/or detection comb structures attached in connection with said at least two seismic masses, and

wherein the at least two seismic masses of the sensor of angular velocity are configured to be activated into a primary motion vibration by means of a common vibration mode, and wherein the at least two seismic masses comprise at least one rotation mass.

2. The sensor of angular velocity according to claim 1, wherein said at least two seismic masses comprise at least one linear mass.

3. The sensor of angular velocity according to claim 1, wherein said detection comb structures are configured to differentially detect the primary motion.

4. The sensor of angular velocity according to claim 1, wherein the electrodes are configured to measure the vibration caused by turning the sensor of angular velocity in relation to the x axis.

5. The sensor of angular velocity according to claim 1, wherein the electrodes are configured to measure the vibration caused by turning the sensor of angular velocity in relation to the y axis.

6. The sensor of angular velocity according to claim 1, wherein the sensor of angular velocity is implemented out of wafer material of the silicon on insulator (SOI) type.

7. The sensor of angular velocity according to claim 1, wherein the structure of the sensor of angular velocity is supported at support areas to a substrate and/or a cover.

8. The sensor of angular velocity according to claim 7, wherein a frame of the sensor of angular velocity is attached to both the substrate and the cover above the structure of the sensor of angular velocity.

9. The sensor of angular velocity according to claim 1, further comprises at least one excitation frame structure.

10. The sensor of angular velocity according to claim 9, wherein said at least two seismic masses are supported to excitation frame structures by means of springs.

11. The sensor of angular velocity according to claim 9, further comprising excitation comb structures configured to activate said at least two seismic masses into primary motion by means of a common mode signal.

12. The sensor of angular velocity according to claim 9, wherein the rotation mass is configured to oscillate, synchronized by the excitation frame structures, in primary motion in the surface plane around the z axis.

13. The sensor of angular velocity according to claim 9, wherein the rotation mass is configured to couple the motions of the excitation frame structures to each other in opposite phase.

14. A vibrating micro-mechanical sensor of angular velocity, comprising:

at least two seismic masses suspended by support structures and/or spring structures; and

spring structures coupling said at least two seismic masses to each other,

wherein the sensor of angular velocity is configured to measure angular velocity in relation to two or three axes by means of electrodes of said at least two seismic masses and/or detection comb structures attached in connection with said at least two seismic masses, and

wherein the at least two seismic masses of the sensor of angular velocity are configured to be activated into a primary motion vibration by means of a common mode,

wherein said at least two seismic masses comprise at least one linear mass,

wherein, inside the linear masses, there are spring structures attached to support structures, wherein the spring structures prevent the motion in primary mode of the detection comb structures detecting angular velocity in the z direction.

15. The vibrating micro-mechanical sensor of angular velocity according to claim 14, further comprising excitation comb structures configured to activate said at least two seismic masses into primary motion by means of a common mode signal.

16. A vibrating micro-mechanical sensor of angular velocity, comprising:

at least two seismic masses suspended by support structures and/or spring structures; and

spring structures coupling said at least two seismic masses to each other,

wherein the sensor of angular velocity is configured to measure angular velocity in relation to two or three axes by means of electrodes of said at least two seismic masses and/or detection comb structures attached in connection with said at least two seismic masses, and

wherein the at least two seismic masses of the sensor of angular velocity are configured to be activated into a primary motion vibration by means of a common mode,

wherein the detection comb structures are configured to measure the vibration caused by turning the sensor of angular velocity in relation to the z axis.

17. The vibrating micro-mechanical sensor of angular velocity according to claim 16, further comprising excitation comb structures configured to activate said at least two seismic masses into primary motion by means of a common mode signal.