MEMS Gyroscope for Determining Rotational Movements about an X, Y, and/or Z Axis

• US 20160025492A1
• Filed: 07/28/2014
• Published: 01/28/2016
• 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
• Granted Patent: US 9,909,873 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 deflections 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. (canceled)

2. A gyroscope comprising:

a substrate;

at least two driving masses that radially oscillate from a central point;

a first drive element coupled to a first driving mass within the at least two driving masses, the first drive element causes oscillating vibration of the first driving mass in order to generate Coriolis forces on the first driving mass in event of rotation of the substrate about a first axis;

a second drive element coupled to a second driving mass within the at least two driving masses, the second drive element causes oscillating vibration of the second driving mass in order to generate Coriolis forces on the second driving mass in the event of rotation of the substrate about a second axis;

a first sensor having a first upper plate and a first lower plate, the first upper plate coupled to the first driving mass such that a deflection of the first upper plate occurs in response to rotation about the first axis; and

a second sensor having a second upper plate and a second lower plate, the second upper plate coupled to the second driving mass such that a deflection of the second upper plate occurs in response to rotation about the second axis.

3. The gyroscope of claim 2 wherein the deflection of the first upper plate causes a first change in capacitance between the first upper plate and the first lower plate, the first change in capacitance relating to a first rate of rotation about the first axis.

4. The gyroscope of claim 2 wherein the deflection of the first upper plate causes a first change in capacitance between the first upper plate and the first lower plate, the first change in capacitance relating to a first rate of rotation about the first axis.

5. The gyroscope of claim 2 wherein the first driving mass radially oscillates along a first path and the second driving mass radially oscillates along a second path, the first and second path being separated by ninety degrees.

6. The gyroscope of claim 5 wherein the first path is along an x-axis and the second path is along a y-axis.

7. The gyroscope of claim 2 further comprising a first suspension spring coupled to the first driving mass and the substrate, the first suspension spring facilitating radial oscillation of the first driving mass.

8. The gyroscope of claim 7 further comprising a second suspension spring coupled to the second driving mass and the substrate, the second suspension spring facilitating radial oscillation of the second driving mass.

9. The gyroscope of claim 2 at least one synchronization spring coupled to the first and second driving masses, the at least one synchronization spring synchronizes the oscillation of the first and second driving masses.

10. The gyroscope of claim 2 further comprising:

a first interface on which a signal is transmitted relating to a first rate of rotation about the first axis; and

a second interface on which a signal is transmitted relating to a second rate of rotation about the second axis.

11. A gyroscope comprising:

a substrate;

a first pair of driving masses that radially oscillate from a central point, the first pair of driving masses is synchronized and each oscillates along a first axis;

a first drive element coupled to a first driving mass within the first pair of driving masses, the first drive element causes oscillating vibration of the first driving mass in order to generate Coriolis forces on the first driving mass in event of rotation of the substrate about the first axis;

a second drive element coupled to a second driving mass within the first pair of driving masses, the second drive element causes oscillating vibration of the second driving mass in order to generate Coriolis forces on the second driving mass in the event of rotation of the substrate about the first axis;

a first sensor having a first upper plate and a first lower plate, the first upper plate coupled to the first driving mass such that a deflection of the first upper plate occurs in response to rotation about the first axis; and

a second sensor having a second upper plate and a second lower plate, the second upper plate coupled to the second driving mass such that a deflection of the second upper plate occurs in response to rotation about the second axis.

12. The gyroscope of claim 11 further comprising:

a first interface on which a first signal is transmitted relating to a first sensed rate of rotation about the first axis from the first sensor; and

a second interface on which a second signal is transmitted relating to a second sensed rate of rotation about the first axis from the second sensor.

13. The gyroscope of claim 12 wherein a differential value related to a rate of rotation about the first axis is derived from the first and second signals.

14. The gyroscope of claim 13 further comprising a central anchor coupled to the substrate, the central anchor having at least one first spring coupled to the first driving mass and at least one second spring coupled to the second driving mass.

15. The gyroscope of claim 13 wherein the first axis is an x-axis.

16. The gyroscope of claim 13 further comprising:

a first flexural spring coupled to the first driving mass and the substrate, the first flexural spring facilitates radial oscillation of the first driving mass relative to the central anchor; and

a second flexural spring coupled to the second driving mass and the substrate, the second flexural spring facilitates radial oscillation of the second driving mass relative to the central anchor.

17. The gyroscope of claim 12 wherein the first signal is generated by a capacitance change caused by the deflection of the first upper plate within the first sensor.

18. The gyroscope of 12 further comprising a third sensor located above the first driving mass, the third sensor comprising a plurality of capacitive plates that detect rotation of the substrate about a third axis.

19. The gyroscope of claim 18 wherein the third axis is a z-axis.

20. A gyroscope comprising:

a substrate;

a first drive mass that radially oscillates from a central anchor, the first drive mass oscillates along a first axis;

a second drive mass that radially oscillates from the central anchor, the second drive mass oscillates along a second axis that is ninety degrees from the first axis;

a third drive mass that radially oscillates from the central anchor, the third drive mass oscillates along the first axis;

a fourth drive mass that radially oscillates from the central anchor, the third drive mass oscillates along the second axis;

a first drive element coupled to a first driving mass, the first drive element causes oscillating vibration of the first driving mass in order to generate Coriolis forces on the first driving mass in event of rotation of the substrate about a first axis;

a second drive element coupled to the third driving mass, the second drive element causes oscillating vibration of the third driving mass in order to generate Coriolis forces on the third driving mass in the event of rotation of the substrate about a second axis;

a first flexural spring coupled to the first and second driving masses, the first flexural spring causing synchronized radial oscillation of the second driving mass relative to the first driving mass;

a second flexural spring coupled to the third and the fourth driving masses, the second flexural spring causing synchronized radial oscillation of the fourth driving mass relative to the third driving mass;

a first sensor having a first upper plate and a first lower plate, the first upper plate coupled to the first driving mass such that a deflection of the first upper plate occurs in response to rotation about the first axis;

a second sensor having a second upper plate and a second lower plate, the second upper plate coupled to the second driving mass such that a deflection of the second upper plate occurs in response to rotation about the second axis;

a third sensor having a third upper plate and a third lower plate, the third upper plate coupled to the third driving mass such that a deflection of the third upper plate occurs in response to rotation about the first axis; and

a fourth sensor having a fourth upper plate and a fourth lower plate, the fourth upper plate coupled to the fourth driving mass such that a deflection of the fourth upper plate occurs in response to rotation about the second axis.