Angular velocity sensor

• US 6,941,810 B2
• Filed: 12/05/2002
• Issued: 09/13/2005
• Est. Priority Date: 03/30/1993
• Status: Expired due to Fees

• Current Assignee: Wacoh Company
• Original Assignee: Kazuhiro Okada
• Inventors: Okada, Kazuhiro
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US10/313,125
• Publication Number:
  US 20030094046A1
• Time in Patent Office: 1,013 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/041.3, 735/041.4, 735/041.5, 735/041.6, 735/143.2, 735/10, 735/11
• US Class Current: 73/504.02
• 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: G01P 15/0907 of the compression mode type
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type
• CPC Class Codes: G01P 15/11 by inductive pick-up
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass

Abstract

An angular velocity sensor for detecting an angular velocity component includes an oscillator having mass, a sensor casing for accommodating the oscillator therewithin, a flexible member for connecting the oscillator to the sensor casing so that the oscillator can be moved with respect to the sensor casing, and capacitance elements including a first electrode provided on a surface of the oscillator and a second electrode provided on a surface of a fixed member fixed to the sensor casing.

Claims

1. An angular velocity sensor for detecting an angular velocity component comprising:

an oscillator made of a substrate with thickness enough to obtain a mass sufficient to provide the sensor with a required sensitivity;

a sensor casing for accommodating the oscillator therewithin;

a flexible member for connecting the oscillator to the sensor casing so that the oscillator can be moved with respect to the sensor casing;

an electrical driving device for oscillating the oscillator using electrical energy, the electrical driving device including a first electrode provided on a surface of the oscillator, a second electrode provided on a surface of a fixed member fixed to the sensor casing and an excitation element applying a voltage between the first electrode and the second electrode; and

a capacitance element including a pair of electrodes, a distance between the pair of electrodes being changed based on a deviation of the oscillator caused by Coriolis force.

2. An angular velocity sensor according to claim 1, wherein the oscillator is made of a silicon substrate.