ANGULAR VELOCITY SENSOR

• US 20090205423A1
• Filed: 02/13/2009
• Published: 08/20/2009
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takagi, Makoto, Kandori, Atsushi
• Granted Patent: US 8,176,780 B2
• Time in Patent Office: Days
• US Class Current: 73/504.140
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames

Abstract

An angular velocity sensor includes a supporting substrate, a detecting portion, a displacement detecting portion, a first driving portion, and a second driving portion. The detecting portion is supported by the supporting substrate movably in at least a free direction. The displacement detecting portion detects a displacement of the detecting portion in the free direction. The first driving portion excites a first reference oscillation of at least a portion of the detecting portion so that a first Coriolis'"'"' force in the free direction is generated in response to an angular velocity about a first axis. The second driving portion excites a second reference oscillation of at least a portion of the detecting portion so that a second Coriolis'"'"' force in the free direction is generated in response to an angular velocity about a second axis.

Claims

1. An angular velocity sensor comprising:

a supporting substrate;

a detecting portion configured to be supported by the supporting substrate movably in at least a free direction;

a displacement detecting portion configured to detect a displacement of the detecting portion in the free direction;

a first driving portion configured to excite a first reference oscillation of at least a portion of the detecting portion so that a first Coriolis'"'"' force in the free direction is generated in response to an angular velocity about a first axis;

a second driving portion configured to excite a second reference oscillation of at least a portion of the detecting portion so that a second Coriolis'"'"' force in the free direction is generated in response to an angular velocity about a second axis different from the first axis.

2. An angular velocity sensor according to claim 1, wherein the second driving portion excites the second reference oscillation so that the second Coriolis'"'"' force is separable from the first Coriolis'"'"' force, and the angular velocity sensor further comprises a controlling portion configured to separate signals respectively corresponding to displacements of the detecting portion, which are detected by the displacement detecting portion and respectively caused by the first Coriolis'"'"' force and the second Coriolis'"'"' force, to detect angular velocities about the first axis and the second axis.

3. An angular velocity sensor according to claim 1, wherein the free direction is a direction of a third axis different from the first axis and the second axis.

4. An angular velocity sensor according to claim 3, wherein the detecting portion is supported movably in a direction of the first axis and a direction of the second axis, and the detecting portion executes the first reference oscillation and the second reference oscillation respectively excited by the first driving portion and the second driving portion.

5. An angular velocity sensor according to claim 3, wherein the detecting portion includes a first mass portion movably supported in the direction of the second axis, and a second mass portion movably supported in the direction of the first axis, the first mass portion executes the first reference oscillation excited by the first driving portion, and the second mass portion executes the second reference oscillation excited by the second driving portion.

6. An angular velocity sensor according to claim 1, wherein the detecting portion includes a first mass portion movably supported in the direction of the third axis and arranged on the first axis, and a second mass portion movably supported in the direction of the third axis and arranged on the second axis, and the free direction of the detecting portion is a direction about a third axis different from the first axis and the second axis.

7. An angular velocity sensor according to claim 6, wherein the first mass portion and the second mass portion include a plurality of mass pieces, respectively, and the mass pieces for generating equivalent Coriolis'"'"' forces of each of the first mass portion and the second mass portion are arranged on one of two axes mutually orthogonal to each other with a rotational center of the detecting portion being an origin, sandwiching the other of the two axes therebetween.

8. An angular velocity sensor according to claim 7, wherein the mass pieces for generating equivalent Coriolis'"'"' forces of each of the first mass portion and the second mass portion perform oscillations with mutually inverse phases, respectively.

9. An angular velocity sensor according to claim 2, wherein the controlling portion includes an output data controlling portion and a drive controlling portion, and the output data controlling portion commands the drive controlling portion to excite the first reference oscillation and the second reference oscillation alternately, and divides signals of angular velocities about two axes into mutually separable forms, using information of selectively excited reference oscillation.

10. An angular velocity sensor according to claim 2, wherein the controlling portion includes an output data controlling portion and a drive controlling portion, the drive controlling portion excites the first reference oscillation and the second reference oscillation at mutually different frequencies, and the output data controlling portion divides signals of angular velocities about two axes into mutually separable forms, using a method of frequency separation.

11. An angular velocity sensor according to claim 1, wherein each of the first and second driving portions comprises a plurality of movable comb-tooth electrodes and a plurality of stationary comb-tooth electrodes.

12. An angular velocity sensor according to claim 1, wherein the detecting portion is supported by the supporting substrate through springs.

13. A method of using the angular velocity sensor according to claim 1, comprising dividing information of a detected displacement of the detecting portion into separable signals.