MEMS gyroscope for detecting rotational motions about an X-, Y-, and/or Z-axis

• US 8,789,416 B2
• Filed: 02/11/2010
• Issued: 07/29/2014
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Hanking Electronics Hongkong Company Limited
• Original Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Inventors: Rocchi, Alessandro
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/203,545
• Publication Number:
  US 20110303007A1
• Time in Patent Office: 1,629 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/11, 735/10, 735/041.4, 735/041.5, 735/041.6
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

The invention relates to a MEMS gyroscope for detecting rotational motions about an x-, y-, and/or Z-axis, in particular a 3-D sensor, containing a substrate, several, at least two, preferably four, drive masses (2) that are movable radially With respect to a center and drive elements (7) for the oscillating vibration of the drive masses (2) in order to generate Coriolis forces on the drive masses (2) in the event of rotation of the substrate about the x-, y-, and/or Z-axis. The oscillating drive masses (2) are connected to at least one further non oscillating sensor mass (3) that however can be rotated about the x-, y-, and/or Z-axis together With the oscillating drive masses (2) on the substrate. Sensor elements (9, 10) are used to detect detections of the sensor mass (3) and/or drive masses (2) in relation to the substrate due to the generated Coriolis forces. At least two, preferably four anchors (5) are used to rotatably fasten the sensor mass (3) to the substrate by means of springs (4).

Claims

1. MEMS gyroscope for detecting rotary movements about an x, y and/or z axis comprising,

a substrate;

at least two driving masses, wherein the driving masses are movable radially relative to a central point; and

drive elements for oscillating vibration of the driving masses in order to generate Coriolis forces on the driving masses in event of rotation of the substrate about the x, y and/or z axis,

wherein the oscillating driving masses are connected to at least one additional sensor mass, which is non-oscillating but which can be rotated on the substrate about the x, y and/or z axis together with the oscillating driving masses and with sensor elements, in order to detect displacements of sensor mass and/or the driving masses in relation to the substrate as a result of generated Coriolis forces, and with at least two anchoring devices for rotary attachment of the sensor mass to the substrate by means of springs and

the driving masses are driven in as oscillatory manner in drive direction without exerting a relevant influence on the sensor mass.

2. MEMS gyroscope according to claim 1 wherein the sensor mass encloses the driving masses as a frame.

3. MEMS gyroscope according to according to claim 1 wherein the driving masses are arranged in pairs and point-symmetrically relative to central point of sensor in order to balance out drive vibrations.

4. MEMS gyroscope according to claim 1 wherein the sensor elements for detecting the displacement of the driving masses and the sensor mass about x and/or y axis are arranged below sensor mass and/or the driving masses as horizontal plate capacitances or are arranged within the sensor mass as vertical capacitances.

5. MEMS gyroscope according to claim 1 wherein the sensor elements to detect displacement of driving masses and the sensor mass about the z axis are arranged within and/or outside the sensor mass as vertical capacitances or as comb electrodes.

6. MEMS gyroscope according to claim 1 wherein the sensor mass is attached to the substrate by flexural springs.

7. MEMS gyroscope according to claim 1 wherein flexural springs enable rotation of the sensor mass about the x, y and z axes.

8. MEMS gyroscope according to claim 1 wherein flexural springs are designed in such a way that the flexural springs prevent the displacement of the sensor mass in the x, y or z direction.

9. MEMS gyroscope according to claim 1 wherein the anchoring devices are arranged in a region of the central point.

10. MEMS gyroscope according to claim 1 wherein the anchoring devices are arranged between the driving masses.

11. MEMS gyroscope according to claim 1 wherein the driving masses are attached to the sensor mass by means of flexural springs that are elastic in the drive direction.

12. MEMS gyroscope according to claim 1 wherein the driving masses are connected together by synchronising springs.

13. MEMS gyroscope according to claim 1 wherein if the driving directions of the driving masses are inclined relative to each other, with four driving masses inclination is a 90°

angle or with three driving masses the inclination is a 120°

angle.

14. MEMS gyroscope according to claim 1 wherein drive directions are provided at an angle of 45°

to x/y axes.

15. MEMS gyroscope according to claim 1 wherein the drive elements of the drive masses are electrodes or fork electrodes.

16. MEMS gyroscope according to claim 1 wherein number of driving masses is four.

17. MEMS gyroscope according to claim 1 wherein number of anchoring devices is four.