Tuning bar vibrator and vibrating gyroscope using the same

• US 7,770,450 B2
• Filed: 01/16/2009
• Issued: 08/10/2010
• Est. Priority Date: 07/21/2006
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Koike, Masato, Fujimoto, Katsumi
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US12/355,034
• Publication Number:
  US 20090133497A1
• Time in Patent Office: 571 Days
• Field of Search: 735/041.2, 735/040.4, 735/041.6, 735/040.2, 735/041.4, 735/041.5, 310/370
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5621 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure
• CPC Class Codes: H03H 9/21 Crystal tuning forks

Abstract

A tuning bar vibrator formed on a substrate and including a vibrating body. The vibrating body is formed into a meander shape as a whole, and a middle vibrating reed is used as a first detection unit. At one end side of the vibrating body, two sensing electrodes are formed and connected respectively to two extended electrodes. A further sensing electrode and a common electrode are formed on a first principal surface of the first detection unit. A common electrode formed on a second principal surface of the vibrating body is connected to the common electrode on the first principal surface via a through-hole. The further sensing electrode and the common electrode are connected respectively to another set of extended electrodes. A tuning bar vibrator that is small in size, may be reduced in profile and may be used as a vibrating gyroscope having a desirable detection sensitivity, and a vibrating gyroscope using the tuning bar vibrator are obtained.

Claims

1. A tuning bar vibrator comprising:

a meander-shaped vibrating body having a first principal surface and a second principal surface;

two driving electrodes extending from a first end side of the first principal surface of the vibrating body in a longitudinal direction thereof to a middle portion of the first principal surface of the vibrating body, the two driving electrodes being separated in a width direction of the vibrating body;

a sensing electrode that extending from a second end side of the first principal surface of the vibrating body in the longitudinal direction thereof to the middle portion of the first principal surface;

a metal film on the second principal surface of the vibrating body; and

a support portion located at a portion of the vibrating body corresponding to a node when the vibrating body bends and vibrates, and that supports the vibrating body.

2. The tuning bar vibrator according to claim 1, wherein the vibrating body comprises a plurality of vibrating reeds arranged parallel to each other.

3. The tuning bar vibrator according to claim 2, wherein a middle vibrating reed of the plurality of vibrating reeds is connected to adjacent vibrating reeds at a center thereof.

4. The tuning bar vibrator according to claim 3, wherein the plurality of vibrating reeds other than the middle vibrating reed are connected alternatively at different ends thereof.

5. The tuning bar vibrator according to claim 3, wherein the plurality of vibrating reeds other than the middle vibrating reed are connected alternatively between different ends and a center thereof.

6. The tuning bar vibrator according to claim 2, wherein the plurality of vibrating reeds other than a middle vibrating reed are connected alternatively at different ends thereof.

7. The tuning bar vibrator according to claim 2, wherein the plurality of vibrating reeds other than a middle vibrating reed are connected alternatively between different ends and a center thereof.

8. The tuning bar vibrator according to claim 1, further comprising a first detection unit that extends in a direction that intersects with the longitudinal direction of the vibrating body at a substantially middle portion of the vibrating body in the longitudinal direction, wherein the sensing electrode is formed on a surface of the first detection unit.

9. The tuning bar vibrator according to claim 8, further comprising a second detection unit connected to each end of the first detection unit and extending in the longitudinal direction of the vibrating body on each side of the vibrating body in a width direction thereof.

10. The tuning bar vibrator according to claim 1, wherein the vibrating body comprises two piezoelectric substrates.

11. The tuning bar vibrator according to claim 10, wherein, the two piezoelectric substrates are polarized in opposite directions with respect to each other in a thickness direction thereof.

12. The tuning bar vibrator according to claim 1, wherein the vibrating body comprises a piezoelectric substrate and a non-piezoelectric substrate.

13. The tuning bar vibrator according to claim 12, wherein the piezoelectric substrate and the non-piezoelectric substrate are polarized in a thickness direction thereof.

14. The tuning bar vibrator according to claim 1, wherein the vibrating body comprises a piezoelectric film.

15. A vibrating gyroscope comprising:

the tuning bar vibrator according to claim 1;

a driving unit that applies a driving signal between the two driving electrodes of the tuning bar vibrator; and

a detection unit that detects a signal generated between the sensing electrode and the metal film.