US 6,742,390 B2Granted

Angular velocity sensor

AssigneeMurata Manufacturing Co., Ltd.

InventorsYoichi Mochida, Yoshihiro Konaka

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Abstract

An angular velocity sensor includes four mass members which are connected by retaining beams, and the retaining beams are fixed to a substrate at node portions which correspond to nodes of the retaining beams when the mass members vibrate such that two adjacent mass members are in opposite phases. The mass members vibrate in an X-axis direction while the overall center of gravity is maintained at an approximately constant position. Two mass members disposed at the central region move in a Y-axis direction in accordance with an angular velocity about a Z axis, and the angular velocity is detected on the basis of the displacements thereof. The mass members vibrate in a stable vibrational state and dimensional errors or other problems, are compensated for by their shapes that are symmetric to each other in the Y-axis direction. Accordingly, the detection accuracy and reliability of the sensor are improved.

Claims22

Dependent claims

An angular velocity sensor comprising:

a substrate;
four mass members which face the substrate with a gap between each of the four mass members and the substrate, the four mass members being arranged along a Y-axis direction when X, Y, and Z axes that are perpendicular to each other are defined;
retaining beams which connect the four mass members such that the four mass members can move in the X-axis direction;
a fixing member disposed between the substrate and the retaining beams to fix the retaining beams to the substrate;
a vibration generator which vibrates at least one of the four mass members in the X-axis direction so that each of the adjacent mass members vibrate in opposite phases;
and
an angular velocity detector which detects an angular velocity on the basis of displacements of two of the four mass members which are disposed symmetrically about a central position in the Y-axis direction when the two mass members disposed symmetrically about the central position move in at least one of the Y and Z-axis directions by the angular velocity.

4 more elements

Dependencies are inferred from the claim text.