Patent ID: 6023974
Filing Date: 2000-02-15
Classification: G01C

Abstract:
An angular velocity sensor device comprising a substrate manufactured of an insulating material, and a Z-axis angular velocity sensing body provided on the substrate, for sensing angular velocity about a Z axis, as the axis of rotation, in a direction perpendicular to the substrate;the Z-axis angular velocity sensing body comprising:a first beam which extends along the principal surface of the substrate with one end of the first beam fixed to the substrate wherein the driving force of a vibration driving source causes a vibration to be imparted to the first beam in an X-axis direction along the surface of the substrate;a second beam which extends perpendicular to the first beam along the surface of the substrate and which follows an elliptical trajectory along the surface of the substrate in response to the resultant force from the force in the X-axis direction provided via the first beam and a Coriolis force acting in an Y-axis direction perpendicular to the X-axis direction along the surface of the substrate;an X-axis vibration detection electrode provided opposite the first beam and together with the first beam forming a vibration detection capacitor; anda Y-axis Coriolis force sensing electrode provided opposite to the second beam and together with the second beam forming a Coriolis force sensing capacitor,wherein the capacitance of the vibration detection capacitor varies in response to the magnitude of the gap between the first beam and the X-axis vibration detection electrode, and the driving force of the vibration driving source is regulated by the value of the capacitance so as to put the first beam in a predetermined vibration state; andwherein the capacitance of the Coriolis force sensing capacitor varies in response to the magnitude of the gap between the second beam and the Y-axis Coriolis sensing electrode, and the angular velocity about the Z axis as the axis of rotation is sensed from the value of the capacitance of the Coriolis force sensing capacitor.