ANGULAR RATE SENSOR

• US 20090173156A1
• Filed: 12/23/2008
• Published: 07/09/2009
• Est. Priority Date: 12/26/2007
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Fujimori, Yoshikazu, Takaoka, Masaki, Kaminishi, Daisuke
• Granted Patent: US 8,136,399 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure

Abstract

An angular rate sensor includes: a substrate; and a vibrator having a beam part supported in a state of floating from the substrate and a pair of supports formed on the substrate and provided at both ends of the beam part for supporting the beam part. The vibrator includes a piezoelectric film formed in the beam part, a detecting electrode for detecting an angular rate, the detecting electrode being formed on the piezoelectric film so as to extend toward a center portion of the beam part from one end thereof, and a driving electrode for vibrating the vibrator, the driving electrode being formed on the piezoelectric film so as to extend toward the center portion of the beam part from the other end thereof and to be spaced from the detecting electrode.

Claims

1. An angular rate sensor comprising:

a substrate; and

a vibrator having a beam part supported in a state of floating from the substrate and a pair of supports formed on the substrate and provided at both ends of the beam part for supporting the beam part, wherein

the vibrator includes

a piezoelectric film formed in the beam part,

a detecting electrode formed on the piezoelectric film so as to extend toward a center portion of the beam part from one end of the beam part, the detecting electrode for detecting an angular rate, and

a driving electrode formed on the piezoelectric film so as to extend toward the center portion of the beam part from the other end of the beam part and to be spaced from the detecting electrode, the driving electrode for vibrating the vibrator.

2. The angular rate sensor according to claim 1, wherein

the supports extend in a direction intersecting with the beam part.

3. The angular rate sensor according to claim 1, wherein

a part of each of the supports is supported in a state of floating from the substrate.

4. The angular rate sensor according to claim 3, wherein the supports are bent.

5. An angular rate sensor comprising:

a substrate; and

a cantilever vibrator having a piezoelectric film, wherein

the vibrator includes

a detector extending from the substrate and having a detecting electrode formed therein for detecting an angular rate, the detector being capable of vibration, and

a resonance frequency regulator provided at a front end of the detector, the resonance frequency regulator being capable of regulating a resonance frequency of the detector.

6. The angular rate sensor according to claim 5, wherein

the resonance frequency regulator has a linear shape extending in the same direction as that of the detector.

7. The angular rate sensor according to claim 5, wherein

a width of the detector is larger than a width of the resonance frequency regulator.

8. The angular rate sensor according to claim 5, wherein

a width of the detector is larger than a thickness of the detector, and

a width of the resonance frequency regulator is smaller than a thickness of the resonance frequency regulator.

9. The angular rate sensor according to claim 5, wherein

the resonance frequency regulator is provided at a center portion in a width direction of the detector.

10. The angular rate sensor according to claim 5, wherein

a plurality of the resonance frequency regulators are provided, and

the plurality of resonance frequency regulators are symmetric about a center portion of the detector.