Angular velocity sensing device

• US 6,151,964 A
• Filed: 05/24/1999
• Issued: 11/28/2000
• Est. Priority Date: 05/25/1998
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Nakajima, Fumio
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US09/317,428
• Time in Patent Office: 554 Days
• Field of Search: 73/504.12, 73/504.13, 73/504.14
• US Class Current: 73/504.13
• CPC Class Codes: G01C 19/5684 the devices involving a micromechanical structure

Abstract

The angular velocity sensing device is structured in such a manner that a first vibration element 1 having piezoelectric elements or electrodes (two or more) for generating oscillation and a second vibration element 2 having piezoelectric elements or electrodes (two or more) for sensing angular velocity are connected through first connection portions (two or more) on nodes of vibration (two or more) of the first vibration element 1, and the second vibration element 2 and a supporting portion are connected with each other through second connection portions (two or more). These first, second vibration elements, the supporting portion, and the first, second connection portions have a plane structure with almost uniform thickness, and both of the first vibration element and the second vibration element are made to have symmetric shapes with respect to the common center point P.

Claims

1. An angular velocity sensing device comprising:

a first vibration element having a piezoelectric element or an electrode for generating oscillation;

a second vibration element having a piezoelectric element or an electrode for sensing angular velocity;

a supporting portion;

first connection portions to connect nodes of vibration of said first vibration element with said second vibration element; and

second connection portions to connect said second vibration element with said supporting portion,

wherein said first and second vibration elements, said supporting portion, and said first and second connection portions have a plane structure with almost uniform thickness, and both of said first and second vibration elements have shapes symmetric with respect to a common center point.

2. The angular velocity sensing device according to claim 1, wherein said first vibration element and said second vibration element are formed in a concentric ring-shape.

3. The angular velocity sensing device according to claim 2, wherein said first vibration element is disposed in the inside of said second vibration element, and said supporting portion is disposed in the outside of said second vibration element.

4. The angular velocity sensing device according to claim 2, wherein said first vibration element is disposed in the outside of said second vibration element and said supporting portion is disposed in the inside of said second vibration element.

5. The angular velocity sensing device according to claim 1, wherein said first and second vibration elements are formed from metal or silicon.

6. The angular velocity sensing device according to claim 1, wherein said first and second vibration elements are formed from a single crystal having piezo-electricity.

7. The angular velocity sensing device according to claim 6, wherein said single crystal having the piezo-electricity is any one of a quartz single crystal, a lithium tantalate single crystal and a lithium borate single crystal.

8. The angular velocity sensing device according to claim 1, wherein said first, second vibration elements, said supporting portion, and said first and second connection portions are integrally formed with the same material.

9. The angular velocity sensing device according to claim 6, wherein said first vibration element is a ring-shaped vibration element having electrodes for generating oscillation on the portions of antinode of the vibration, and said second vibration element is a ring-shaped vibration element having electrodes for sensing angular velocity at the positions corresponding to the electrodes for generating oscillation of said first vibration element.

10. The angular velocity sensing device according to claim 9, wherein said ring-shaped first vibration element, second vibration element, said first and second connection portions, and said supporting portion are integrally formed with a single crystal having piezo-electricity.

11. An angular velocity sensing device, comprising:

a first vibration element having a piezoelectric element or an electrode for generating oscillation;

a second vibration element having a piezoelectric element or an electrode for sensing angular velocity;

a third vibration element;

a supporting portion to support said first vibration element or said second vibration element;

connection portions to connect nodes of vibration of said first vibration element with said third vibration element; and

connection portions to connect said third vibration element with said second vibration element,

wherein said first, second, and third vibration elements, said supporting portion, and each of said connection portions form a plane structure with almost uniform thickness and each of said first, second, third vibration elements have a shape symmetric with respect to a common center point.

12. The angular velocity sensing device according to claim 11, wherein said first, second, third vibration elements, said supporting portion, and said first and second connection portions are integrally formed with the same material, and each of said first, second, and third vibration elements is formed in a concentric ring-shape.

13. The angular velocity sensing device according to claim 12,

wherein said first, second and third vibration elements, said supporting portion, and said first and second connection portions are integrally formed with a single crystal quartz Z-plate;

wherein said first vibration element is a ring-shaped vibration element having said electrodes for generating the oscillation on positions symmetric with respect to the Y-axis of said single crystal quartz Z-plate; and

wherein said second vibration element is a ring-shaped vibration element having said electrodes for sensing the angular velocity on positions symmetric with respect to the Y-axis of said single crystal quartz Z-plate.