Physical quantity detection vibrator element, physical quantity detection apparatus, electronic apparatus, and moving object

• US 10,072,928 B2
• Filed: 10/27/2016
• Issued: 09/11/2018
• Est. Priority Date: 10/28/2015
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ishii, Masahiro, Yamaguchi, Keiichi, Kikuchi, Takayuki
• Primary Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US15/336,404
• Publication Number:
  US 20170122738A1
• Time in Patent Office: 684 Days
• Field of Search: 73597
• 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 19/5614 Signal processing
• CPC Class Codes: H10N 30/302 Sensors

Abstract

A vibrator element has a detection arm that performs a drive vibration in a Z-axis direction, and performs a detection vibration in an X-axis direction when an angular velocity is applied thereto The vibrator element also has first, second, third, and fourth electrode portions and first, second, third, and fourth ground electrode portions provided on a detection arm. Further, a signal generated between the first electrode portion and the first ground electrode portion and a signal generated between the second electrode portion and the second ground electrode portion are in opposite phase in a drive vibration and in phase in a detection vibration. Furthermore, a signal generated between the third electrode portion and the third ground electrode portion and a signal generated between the fourth electrode portion and the fourth ground electrode portion are in opposite phase in the drive vibration and in phase in the detection vibration.

Claims

1. A physical quantity detection vibrator element comprising:

a detection arm that includes a piezoelectric material, performs a drive vibration in a first direction, and performs a detection vibration in second direction orthogonal to the first direction when a physical quantity is applied thereto; and

a first detection signal electrode, a second detection signal electrode, and a reference potential electrode provided on the detection arm;

wherein;

the first detection signal electrode includes a first electrode portion and a second electrode portion;

the second detection signal electrode includes a third electrode portion and a fourth electrode portion;

the reference potential electrode includes;

(a) a first reference potential electrode portion at a reference potential with respect to the first electrode portion;

(b) a second reference potential electrode portion at the reference potential with respect to the second electrode portion;

(c) a third reference potential electrode portion at the reference potential with respect to the third electrode portion; and

(d) a fourth reference potential electrode portion at the reference potential with respect to the fourth electrode portion;

a first signal generated between the first electrode portion and the first reference potential electrode portion and a second signal generated between the second electrode portion and the second reference potential electrode portion are in opposite phase with each other when the drive vibration is performed and in phase with each other when the detection vibration is performed; and

a third signal generated between the third electrode portion and the third reference potential electrode portion and a fourth signal generated between the fourth electrode portion and the fourth reference potential electrode portion are in opposite phase with each other when the drive vibration is performed and in phase with each other when the detection vibration is performed.

2. The physical quantity detection vibrator element according to claim 1, wherein a first plane is defined normal the first direction and the detection arm further includes:

a first projection portion projecting away from the first plane on one side of the first plane;

a second projection portion projecting away from the first plane on the other side of the first plane;

a third projection portion projecting away from the first plane on the one side of the first plane beside the first projection portion; and

a fourth projection portion projecting away from the first plane on the other side of the first plane beside the second projection portion,

wherein the first electrode portion and the first reference potential electrode portion are provided with the first projection portion in between,

the second electrode portion and the second reference potential electrode portion are provided with the second projection portion in between,

the third electrode portion and the third reference potential electrode portion are provided with the third projection portion in between, and

the fourth electrode portion and the fourth reference potential electrode portion are provided with the fourth projection portion in between.

3. The physical quantity detection vibrator element according to claim 1, further comprising:

a pair of drive arms provided with the detection arm in between; and

a base part connected to the detection arm and to the pair of drive arms.

4. The physical quantity detection vibrator element according to claim 3, further comprising a second detection arm with the base part located in between the detection arms.

5. The physical quantity detection vibrator element according to claim 3, wherein a first plane is defined normal the first direction, a second plane is defined normal the second direction, and each of the drive arms includes:

a drive arm first principal surface provided on one side of the first plane;

a drive arm second principal surface provided on the other side of the first plane,

a drive arm first side surface provided on one side of the second plane;

a drive arm second side surface provided on the other side of the second plane;

a drive arm first groove portion provided in the drive arm first principal surface;

a drive arm second groove portion provided in the drive arm second principal surface;

a first step portion located in the drive arm first groove portion on the one side of the second plane and connecting the drive arm first principal surface and the drive arm first side surface; and

a second step portion located in the drive arm second groove portion on the other side of the second plane and connecting the drive arm second principal surface and the drive arm second side surface,

a tip end of the first stepped portion in a third direction orthogonal to the first direction and second direction is located closer to a tip end side of the drive arm than a tip end of the drive arm first groove portion in the third direction; and

a tip end of the second stepped portion in the third direction is located closer to a tip end side of the drive arm than a tip end of the drive arm second groove portion in the third direction.

6. A physical quantity detection apparatus comprising:

the physical quantity detection vibrator element according to claim 1; and

a circuit electrically connected to the physical quantity detection vibrator element.

7. An electronic apparatus comprising the physical quantity detection vibrator element according to claim 1.

8. A moving object comprising the physical quantity detection vibrator element according to claim 1.

9. The physical quantity detection vibrator element according to claim 1, further comprising:

a base part;

a pair of the detection arms extending from the base part in opposite directions along a third direction orthogonal to the first direction and second direction;

a pair of connecting arms extend from the base in opposite directions parallel to the second plane;

a first pair of drive arms extend from one connecting arm in opposite directions parallel to the first plane; and

a second pair of drive arms extend from the other of the pair of connecting arms in opposite directions to each other along the first plane.

10. The physical quantity detection vibrator element according to claim 9, further comprising:

a first weight portion provided on a surface of the one detection arms on one side of the first plane; and

a second weight portion provided on a surface of the other detection arms on the other side of the first plane.

11. A physical quantity detection vibrator element comprising:

a detection arm that includes a piezoelectric material, performs a drive vibration in a first direction, and performs a detection vibration in a second direction orthogonal to the first directions when a physical quantity is applied thereto; and

a first detection signal electrode and a second detection signal electrode provided on the detection arm;

wherein;

the first detection signal electrode includes a first electrode portion and a second electrode portion;

the second detection signal electrode includes a third electrode portion and a fourth electrode portion;

a signal generated between the first electrode portion and the third electrode portion and a signal generated between the second electrode portion and the third electrode portion are in opposite phase with each other when the drive vibration is performed and in phase with each other when the detection vibration is performed; and

a signal generated between the first electrode portion and the fourth electrode portion and a signal generated between the second electrode portion and the fourth electrode portion are in opposite phase with each other when the drive vibration is performed and in phase with each other when the detection vibration is performed.

12. The physical quantity detection vibrator element according to claim 11,

wherein a first plane is defined normal the first direction, a second plane is defined normal the second direction, and the detection arm includes:

a detection arm first principal surface provided on one side of the first plane;

a detection arm second principal surface provided on the other side of the first plane;

a detection arm first side surface provided on one side of the second plane;

a detection arm second side surface provided on the other side of the second plane;

a detection arm first groove portion opening in the detection arm first principal surface; and

a detection arm second groove portion opening in the detection arm second principal surface;

wherein;

the first electrode portion is provided in the detection arm first groove portion;

the second electrode portion is provided in the detection arm second groove portion;

the third electrode portion is provided on the detection arm first side surface; and

the fourth electrode portion is provided on the detection arm second side surface.

13. The physical quantity detection vibrator element according to claim 11, further comprising:

a pair of drive arms provided with the detection arm in between; and

a base part connected to the detection arm and to the pair of drive arms are connected.

14. The physical quantity detection vibrator element according to claim 13, further comprising a second detection arm with the base part located in between the detection arms.

15. The physical quantity detection vibrator element according to claim 13, wherein each of the pair of drive arms includes:

a drive arm first principal surface provided on the one side of the first plane;

a drive arm second principal surface provided on the other side of the first plane;

a drive arm first side surface provided on the one side of the second plane;

a drive arm second side surface provided on the other side of the second plane;

a drive arm first groove portion provided in the drive arm first principal surface;

a drive arm second groove portion provided in the drive arm second principal surface;

a first step portion located in the drive arm first groove portion on the one side of the second plane and connecting the drive arm first principal surface and the drive arm first side surface; and

a second step portion located in the drive arm second groove portion on the other side of the second plane and connecting the drive arm second principal surface and the drive arm second side surface;

wherein;

a tip end of the first stepped portion in a third direction orthogonal to the first direction and second direction is located closer to a tip end side of the drive arm than a tip end of the drive arm first groove portion in the third direction; and

a tip end of the second stepped portion in the third direction is located closer to a tip end side of the drive arm than a tip end of the drive arm second groove portion in the third direction.

16. The physical quantity detection vibrator element according to claim 11, further comprising:

a base part;

each detection arm in the pair of the detection arms extends away from the base part in opposite directions along the third direction;

a pair of connecting arms extend from the base part on opposite sides of the second plane;

a first pair of drive arms extend from one of the connecting arms toward opposite sides of the first plane; and

a second pair of drive arms extend from the other connecting arm toward opposite sides of the first plane.

17. The physical quantity detection vibrator element according to claim 16, further comprising:

a first weight portion provided on a surface of the one detection arm on one side of the first directions; and

a second weight portion provided on a surface of the other detection arm on the other side of the first directions.

18. A physical quantity detection apparatus comprising:

the physical quantity detection vibrator element according to claim 11; and

a circuit electrically connected to the physical quantity detection vibrator element.

19. An electronic apparatus comprising the physical quantity detection vibrator element according to claim 11.

20. A moving object comprising the physical quantity detection vibrator element according to claim 11.