Angular velocity detector having inertial mass oscillating in rotational direction

• US 20060112764A1
• Filed: 09/30/2005
• Published: 06/01/2006
• Est. Priority Date: 12/01/2004
• Status: Abandoned Application

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Higuchi, Hirofumi
• Application Number:
  US11/239,084
• Publication Number:
  US 20060112764A1
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

An angular velocity detector includes a disk-shaped inertial mass supported on a substrate via driving beams and a second mass connected to the inertial mass via detecting beams. The inertial mass is oscillated in its rotational direction around a center axis (z) by an electrostatic force. When an angular velocity around a detection axis (x), which is perpendicular to the center axis (z), is imposed on the second mass while the inertial mass is oscillating, the second mass displaces in the direction parallel to the center axis (z). A capacitance between the second mass and the substrate changes according to the displacement of the second mass. The angular velocity is detected based on the changes in the capacitance. Since the driving beams allow the inertial mass to oscillate only in the rotational direction, the driving beams can be easily designed and manufactured.

Claims

1. An angular velocity detector, comprising:

a substrate;

a support fixed to the substrate; and

an inertial mass supported by the support so that the inertial mass oscillates around a center axis that is perpendicular to a plane of the substrate, wherein;

the inertial mass comprises a first mass connected to the support via resilient driving beams and a second mass connected to the first mass via resilient detecting beams so that the second mass displaces in a direction parallel to the center axis upon imposition of an angular velocity around a detection axis that is perpendicular to the center axis when the inertial mass is oscillating around the center axis; and

the angular velocity around the detection axis is detected based on a displacement of the second mass relative to the plane of the substrate in the direction parallel to the center axis.

2. The angular velocity detector as in claim 1, wherein:

the second mass is composed of a pair of pieces positioned along the detection axis and symmetrically with respect to the center axis.

3. The angular velocity detector as in claim 2, wherein:

the second mass further includes a second pair of pieces positioned along a second detection axis, which is perpendicular to the detection axis and parallel to the plane of the substrate, and symmetrically with respect to the center axis; and

an angular velocity around the second detection axis is detected based on a displacement of the second pair of pieces relative to the plane of the substrate.