Vibrating micro-mechanical sensor of angular velocity

• US 20090260437A1
• Filed: 04/15/2009
• Published: 10/22/2009
• 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
• Granted Patent: US 8,176,779 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• 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

The invention relates 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 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 means of 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 (34-36, 52-53, 71-75), which are suspended by means of support structures (19-23, 56-60) and/or spring structures (24-29, 49, 61-66), and spring structures (30-31, 67-68) coupling said masses (34-36, 52-53, 71-75) to each other, characterized in, that

the sensor of angular velocity is adapted to measure angular velocity in relation to two or three axes by means of electrodes (37-40, 76-79) of said masses (34-36, 52-53, 71-75) and/or detection comb structures (44, 47-48, 54-55, 83, 86-87) attached in connection with said masses (34-36, 52-53, 71-75), and that

the at least two seismic masses (34-36, 52-53, 71-75) of the sensor of angular velocity are adapted to be activated into a primary motion vibration by means of a common mode.

2. The sensor of angular velocity according to claim 1, characterized in, that said at least two seismic masses (34-36, 52-53, 71-75) comprise at least one rotation mass (34, 71).

3. The sensor of angular velocity according to claim 1, characterized in, that said at least two seismic masses (34-36, 52-53, 71-75) comprise at least one linear mass (35-36, 52-53, 72-75).

4. The sensor of angular velocity according to claim 1, characterized in, that the sensor of angular velocity additionally comprises at least one excitation frame structure (32-33, 50-51, 69-70).

5. The sensor of angular velocity according to claim 4, characterized in, that said at least two seismic masses (34-36, 52-53, 71-75) are supported to excitation frame structures (32-33, 50-51, 69-70) by means of springs (30-31, 45-46, 67-68, 84-85).

6. The sensor of angular velocity according to claim 4, characterized in, that the sensor of angular velocity additionally comprises excitation comb structures (43, 82), which excitation comb structures (43, 82) are adapted to activate said at least two seismic masses (34-36, 52-53, 71-75) into primary motion by means of a common mode signal.

7. The sensor of angular velocity according to claim 1, characterized in, that said detection comb structures (44, 47-48, 54-55, 83, 86-87) are adapted to differentially detect the primary motion.

8. The sensor of angular velocity according to claim 4, characterized in, that the rotation mass (34, 71) is adapted to oscillate, synchronized by the excitation frame structures (32-33, 50-51, 69-70), in primary motion in the surface plane around the z axis.

9. The sensor of angular velocity according to claim 4, characterized in, that the rotation mass (34, 71) is adapted to couple the motions of the excitation frame structures (32-33, 50-51, 69-70) to each other in opposite phase.

10. The sensor of angular velocity according to claim 3, characterized in, that inside the linear masses (35-36, 52-53, 72-75) there are spring structures (41-42, 80-81) attached to support structures (23, 60), which spring structures prevent the motion in primary mode of the detection comb structures (47-48, 86-87) detecting angular velocity in the z direction.

11. The sensor of angular velocity according to claim 1, characterized in, that the electrodes (37-40, 76-79) are adapted to measure the vibration caused by turning the sensor of angular velocity in relation to the x axis.

12. The sensor of angular velocity according to claim 1, characterized in, that the electrodes (37-40, 76-79) are adapted to measure the vibration caused by turning the sensor of angular velocity in relation to the y axis.

13. The sensor of angular velocity according to claim 1, characterized in, that the detection comb structures (47-48, 54-55, 86-87) are adapted to measure the vibration caused by turning the sensor of angular velocity in relation to the z axis.

14. The sensor of angular velocity according to claim 1, characterized in, that the sensor of angular velocity is implemented out of wafer material of the SOI type (SOI, Silicon on Insulator).

15. The sensor of angular velocity according to claim 1, characterized in, that the structure of the sensor of angular velocity is supported at support areas (19-22, 56-59) to a substrate and/or a cover.

16. The sensor of angular velocity according to claim 1, characterized in, that a frame (23, 60) of the sensor component is attached to both the substrate and the gas space sealing cover above the structure of the sensor of angular velocity.