Angular velocity sensor, electronic apparatus, and method of detecting an angular velocity

• US 8,910,517 B2
• Filed: 12/02/2010
• Issued: 12/16/2014
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Takahashi, Kazuo, Honda, Junichi
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/202,918
• Publication Number:
  US 20110296914A1
• Time in Patent Office: 1,475 Days
• Field of Search: 735/041.2, 735/041.4, 735/041.5, 735/041.6, 735/040.4
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5726 Signal processing
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: H10N 30/00 Piezoelectric or electrostrictive devices integrated devices or assemblies of multiple devices H10N39/00

Abstract

An angular velocity sensor includes an annular frame, a drive part, and a detection part. The frame has first beams and second beams. The first beams extend in an a-axis direction and are opposed to each other in a b-axis direction orthogonal to the a-axis direction. The second beams extend in the b-axis direction and are opposed to each other in the a-axis direction. The drive part causes the frame to oscillate within an XY plane to which the a-axis and the b-axis belong, in an oscillation mode where, when one of the first and second beams come closer to each other, the other separates from each other. The detection part detects an angular velocity around an axis in the Z-axis direction orthogonal to the XY plane, based on an amount of deformation of the frame oscillating in the oscillation mode within the XY plane.

Claims

1. An angular velocity sensor comprising:

an annular frame having;

(a) a first set of beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction;

(b) a second set of beams extending in the second direction and opposed to each other in the first direction; and

(c) a plurality of connection parts connecting the first beams and the second beams;

a drive part configured to cause the annular frame to oscillate within a first plane to which the first and second directions belong, in an oscillation mode where, when one of the first and second sets of beams comes closer to each other, the other set separates from each other, and when the one set separates from each other, the other set comes closer to each other;

a first detection part configured to detect an angular velocity about an axis in a third direction orthogonal to the first and second directions, based on an amount of deformation of the annular frame oscillating in the oscillation mode within the first plane;

a support part which is connected to the connection parts to support the annular frame;

a first pendulum part which is disposed at the connection parts so as to extend in a fourth direction intersecting with the first and second directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame;

a second pendulum part which is disposed at the connection parts so as to extend in a fifth direction intersecting with the first, second, and fourth directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame; and

a second detection part which detects angular velocities about axes in two predetermined directions within the first plane, based on amounts of deformation of the first and second pendulum parts in directions orthogonal to the first plane.

2. The angular velocity sensor of claim 1, wherein the second detection part detects angular velocities about axes in the first and second directions.

3. The angular velocity sensor of claim 1, wherein the second detection part includes a piezoelectric layer disposed on the first and second pendulums to detect electrically deformation of the first and second pendulum parts in directions orthogonal to the first plane.

4. The angular velocity sensor of claim 1, wherein the drive part includes piezoelectric drive layers disposed on the first and second beams.

5. The angular velocity sensor of claim 1, which includes:

(a) a reference part which is disposed on at least one of the first and second beams; and

(b) a piezoelectric layer for detecting deformation of the beam due to oscillation in the oscillation mode.

6. The angular velocity sensor of claim 1, wherein the support part includes:

(a) a base fixed mechanically to a fixing part; and

(b) coupling parts that connect the base with the connection parts and are capable of deformation.

7. The angular velocity sensor of claim 6, wherein the base is formed in the shape of a box surrounding an outside of the annular frame.

8. The angular velocity sensor of claim 6, wherein the base includes an electrode pad connected electrically to the fixing part.

9. The angular velocity sensor of claim 1, wherein the annular frame includes a weight portion formed on at least one of the first and second beams.

12. The angular velocity sensor of claim 1, wherein

the first detection part is disposed on at least one of the first and second beams and includes a piezoelectric layer for detecting electrically deformation of the beam.

13. The angular velocity sensor of claim 1, wherein

the first and second beams have projection parts projecting toward an inside of the annular frame.

10. An angular velocity sensor comprising:

an annular frame having;

(a) a first set of beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction;

(b) a second set of beams extending in the second direction and opposed to each other in the first direction; and

(c) a plurality of connection parts connecting the first beams and the second beams;

a drive part configured to cause the annular frame to oscillate within a first plane to which the first and second directions belong, in an oscillation mode where, when one of the first and second sets of beams comes closer to each other, the other set separates from each other, and when the one set separates from each other, the other set comes closer to each other;

a first detection part configured to detect an angular velocity about an axis in a third direction orthogonal to the first and second directions, based on an amount of deformation of the annular frame oscillating in the oscillation mode within the first plane;

a support part which is connected to the connection parts to support the annular frame;

a first pendulum part which is disposed at the connection parts so as to extend in a fourth direction intersecting with the first and second directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame; and

a second detection part which detects an angular velocity about an axis in the fourth direction, on the basis of an amount of deformation of the first pendulum part in a direction orthogonal to the first plane;

a second pendulum part which is disposed at the connection parts so as to extend in a fifth direction intersecting with the first, second, and fourth directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame; and

a third detection part which detects an angular velocity about an axis in the fifth direction, based on an amount of deformation of the second pendulum part in a direction orthogonal to the first plane.

11. The angular velocity sensor of claim 10, wherein:

(a) the second detection part includes a piezoelectric layer disposed on the first pendulum part to detect electrically deformation of the first pendulum part in a direction orthogonal to the first plane; and

(b) the third detection part includes a piezoelectric layer disposed on the second pendulum part to detect electrically deformation of the second pendulum part in a direction orthogonal to the first plane.

14. An angular velocity sensor comprising:

an annular frame having a first set of beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction, a second set of beams extending in the second direction and opposed to each other in the first direction, and a plurality of connection parts connecting the first beams and the second beams;

a drive part to cause the annular frame to oscillate within a first plane to which the first and second directions belong, in an oscillation mode where, when one of the first and second sets of beams comes closer to each other, the other set separates from each other, and when the one set separates from each other, the other set comes closer to each other;

a first pendulum part which is disposed at the connection parts so as to extend in a third direction intersecting with the first and second directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame;

a second pendulum part which is disposed at the connection parts so as to extend in a fourth direction intersecting with the first, second, and third directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame;

a detection part to detect angular velocities about axes in two predetermined directions within the first plane, based on amounts of deformation of the first and second pendulum parts in directions orthogonal to the first plane; and

a support part which is connected to the connection parts to support the annular frame.

15. An electronic apparatus equipped with an angular velocity sensor comprising:

an annular frame having a first set of beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction, a second set of beams extending in the second direction and opposed to each other in the first direction, and a plurality of connection parts connecting the first beams and the second beams;

a drive part to cause the annular frame to oscillate within a plane to which the first and second directions belong, in an oscillation mode where, when one of the first and second sets of beams comes closer to each other, the other set separates from each other, and when the one set separates from each other, the other set comes closer to each other;

a first detection part to detect an angular velocity about an axis in a third direction orthogonal to the first and second directions, based on an amount of deformation of the annular frame oscillating in the oscillation mode within the plane;

a support part which is connected to the connection parts to support the annular frame

a first pendulum part which is disposed at the connection parts so as to extend in a fourth direction intersecting with the first and second directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame;

a second pendulum part which is disposed at the connection parts so as to extend in a fifth direction intersecting with the first, second, and fourth directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame; and

a second detection part which detects angular velocities about axes in two predetermined directions within the first plane, based on amounts of deformation of the first and second pendulum parts in directions orthogonal to the first plane.

16. A method of detecting an angular velocity comprising:

supporting by a support part an annular frame having a first set of beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction, a second set of beams extending in the second direction and opposed to each other in the first direction, and a plurality of connection parts connecting the first beams and the second beams, the support part being connected to the connection parts;

oscillating the annular frame within a first plane to which the first and second directions belong, in an oscillation mode where, when one of the first and second sets of beams comes closer to each other, the other set separates from each other, and when the one set separates from each other, the other set comes closer to each other; and

detecting an angular velocity about an axis in a third direction orthogonal to the first and second directions, on the basis of an amount of deformation of the annular frame oscillating in the oscillation mode within the first plane, wherein;

(a) a first pendulum part which is disposed at the connection parts so as to extend in a fourth direction intersecting with the first and second directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame;

(b) a second pendulum part which is disposed at the connection parts so as to extend in a fifth direction intersecting with the first, second, and fourth directions within the first plane, and oscillates within the first plane in synchronization with oscillation of the annular frame; and

(c) a detection part which detects angular velocities about axes in two predetermined directions within the first plane, based on amounts of deformation of the first and second pendulum parts in directions orthogonal to the first plane.