MICRO-GYROSCOPE FOR DETECTING MOTIONS

• US 20130031977A1
• Filed: 04/19/2011
• Published: 02/07/2013
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: Hanking Electronics Hongkong Company Limited
• Original Assignee: Maxim Integrated GmbH (Analog Devices, Inc.)
• Inventors: Kempe, Volker
• Granted Patent: US 9,157,740 B2
• Time in Patent Office: Days
• US Class Current: 73/504.04
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5642 using vibrating bars or beams
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames

Abstract

The invention relates to a micro-gyroscope for detecting motions relative to an X and/or Y and Z axis, particularly as a 3D, 5D, or 6D sensor. Sample masses are disposed uniformly about an anchor and can be driven radially relative to the central anchor. Anchor springs are disposed to attach the sample masses to a substrate, and these sample masses can be deflected both radially within and out of the X-Y plane. A sensor mass is disposed on one of the sample masses by means of sensor springs, and the sensor springs allow deflection of the sensor mass within the plane of the sample mass, and orthogonal to the radial drive direction of the sample masses. Drive elements oscillate these sample masses in the X-Y plane, and sensor elements captures the defection of the sample masses due to the Coriolis forces generated when the substrate is rotated.

Claims

1. A micro-gyroscope for detecting motions relative to a Z axis and at least one of an X and Y axis as a multi-dimensional sensor, comprising:

a substrate;

a plurality of anchors including a central anchor, the plurality anchors being fixed on the substrate;

a plurality of oscillating sample masses, the plurality of sample masses being disposed uniformly around the central anchor and driven radially relative to the central anchor;

anchor springs disposed between the anchors and the plurality of oscillating sample masses, the anchor springs for attaching the plurality of oscillating sample masses to the substrate and allowing the plurality of oscillating sample masses to be deflected both radially in a X-Y plane and out of the X-Y plane;

drive elements, the drive elements oscillating the plurality of oscillating sample masses in the X-Y plane to generate Coriolis forces when the substrate is rotated;

sensor elements disposed below the plurality of oscillating sample masses, the sensor elements detecting deflections of the plurality of oscillating sample masses due to the Coriolis forces; and

a sensor mass is disposed on one of the plurality of oscillating sample masses, by means of sensor springs, and

the sensor springs allowing deflection of the sensor mass within the plane of the plurality of oscillating sample masses, and orthogonal to the radial drive direction of these sample masses.

2. The micro-gyroscope according to claim 1, wherein four sample masses are distributed uniformly about the circumference of the central anchor.

3. The micro-gyroscope according to claim 1, wherein an elastic gimbal mount is disposed between the central anchor and the anchor springs.

4. The micro-gyroscope according to claim 3, wherein the elastic gimbal mount comprises two rings coupled to each other by means of torsional springs that are offset from each other.

5. The micro-gyroscope according to claim 1, wherein at least one of the plurality of oscillating sample masses and the sensor masses is implemented in the form of a frame.

6. The micro-gyroscope according to claim 1, wherein the sensor mass is disposed within a frame in the form of which one of the plurality of oscillating sample mass is implemented.

7. The micro-gyroscope according to claim 1, wherein the plurality of oscillating sample masses are coupled to each other by means of synchronization springs.

8. The micro-gyroscope according to claim 1, wherein the sensor elements are associated with the plurality of oscillating sensor masses for detecting a Z rotational rate.

9. The micro-gyroscope according to claim 1, wherein sensor elements for detecting individual deflection in the vertical Z direction are associated with the sample masses.

10. The micro-gyroscope according to claim 1, wherein the sensor elements for detecting the Z deflection of one of the plurality of oscillating sample masses are implemented by the capacitance of the corresponding sample mass and an electrode disposed thereunder on the substrate.

11. The micro-gyroscope according to claim 1, wherein two sensor elements for detecting the Z deflection of two opposing sample masses are combined into a differential sensor for detecting rotation of the substrate about a first axis in the X-Y plane that is perpendicular to a second axis connecting said two opposing sample masses.

12. The micro-gyroscope according to claim 1, wherein the drive elements of the plurality of oscillating sample masses are electrodes.

13. The micro-gyroscope according to claim 1, wherein the sensor elements for detecting the deflection perpendicular to the radius of one of the plurality of oscillating sample masses are disposed in a detection box having shielding electrodes for counter electrodes fixed to the substrate.

14. The micro-gyroscope according to claim 1, wherein the sensor masses are deflected in one circumferential direction when a Z rotational rate is applied, and at least two of the sensor masses are deflected in two opposite circumferential directions when an acceleration of the micro-gyroscope within the X-Y plane is applied, each of the circumferential directions being selected from a clockwise direction and a counterclockwise direction.

15. The micro-gyroscope according to claim 1, wherein the plurality of oscillating sample masses is deflected in the vertical Z direction and at least two sample masses are deflected in the same Z direction in order to derive an acceleration of the micro-gyroscope along the vertical Z axis.

16. The micro-gyroscope according to claim 12, wherein the electrodes are fork electrodes.