Angular speed sensor device

• US 6,526,826 B2
• Filed: 03/19/2001
• Issued: 03/04/2003
• Est. Priority Date: 03/17/2000
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Kato, Manabu, Kurachi, Hideya
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/810,229
• Publication Number:
  US 20010029784A1
• Time in Patent Office: 715 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/041.4, 735/041.5, 735/041.3, 361/280
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

The angular speed sensor device includes a drive frame 11 and a detecting frame 12 which are supported on a silicon substrate 10 in a floating mode. The drive frame 11 and the detecting frame 12 are provided with an angular speed about the z-axis when the drive frame 11 and the detecting frame 12 are driven to vibrate in the x-direction, the resulting Corliolis force causing the detecting frame 12 to oscillate in the y-direction. Such a y-direction oscillation of the detecting frame 12 is detected as a displacement signal. On the basis of the displacement signal, the applied angular speed is calculated. The angular speed sensor device includes detecting electrodes 16a and 16b which drive the detecting frame 12 to vibrate in the y-direction when a drive signal is fed to each of the detecting electrodes 16a and 16b which changes the electrostatic capacitance between the detecting frame 12 and each of the detecting electrodes 16a and 16b. On the basis of the drive signal and the displacement signal which are fed to each of the detecting electrodes 16 and 16b, the resonant frequency of the detecting frame 12 when it is driven to vibrate in the y-direction and the corresponding Q-value are determined.

Claims

1. An angular speed sensor device comprising:

an oscillator mounted on a substrate in a floating mode and brought into vibration in the y-direction in response to Coriolis force which results when the oscillator is supplied with an angular speed about the z-axis while the oscillator is being driven in the x-direction;

detecting means for detecting a y-direction displacement signal of the oscillator; and

a detecting electrode device driving the oscillator in the y-direction when a drive signal is applied thereto which varies an electrostatic attraction between the oscillator and the detecting electrode device,

wherein a resonant frequency of the oscillator in the y-direction and the corresponding Q-value are determined on the basis of the drive signal and the displacement signal.

2. An angular speed sensor device as set forth in claim 1, wherein the detecting electrode device is made up of a first detecting electrode placed at one y-direction side of the oscillator and a second detecting electrode placed at the other y-direction side of the oscillator.

3. An angular speed sensor device as set forth in claim 1, wherein the detecting electrode device is made up of a first detecting electrode and a second detecting electrode which are placed at one y-direction side of the oscillator and which are adjacent each other and extend in the x-direction.

4. An angular speed sensor device as set forth in claim 1, wherein the detecting electrode device is made up of a first detecting electrode and a second detecting electrode which are placed at one y-direction side of the oscillator and which are arranged alternately in the x-direction.

5. An angular speed sensor device as set forth in claim 1, wherein the detecting means includes an angular speed detecting electrode which detects a variable electrostatic capacitance between the oscillator and the angular speed detecting electrode as the displacement signal, wherein a distance in the y-direction between the detecting electrode device and the oscillator is set to be shorter than a distance in the y-direction between the angular speed detecting electrode and the oscillator while the oscillator is at rest.

6. An angular speed sensor device as set forth in claim 2, wherein the detecting means includes first and second angular speed detecting electrodes, each of which detects a variable electrostatic capacitance between the oscillator and the angular speed detecting electrode as a displacement signal, wherein the detecting means includes a differential amplifier for differentially amplifying the detected displacement signal.

7. An angular speed sensor device as set forth in claim 3, wherein the detecting means includes first and second angular speed detecting electrodes, each of which detects a variable electrostatic capacitance between the oscillator and the angular speed detecting electrode as a displacement signal, wherein the detecting means includes a differential amplifier for differentially amplifying the detected displacement signal.