Patent ID: 7387025

Claim:
An angular velocity sensor comprising: an oscillator; a driving portion provided on the oscillator for driving the oscillator in an X-axis direction and a Z-axis direction; a first driving circuit for supplying a driving signal for driving the oscillator in the X-axis direction to the driving portion; a second driving circuit for supplying a driving signal for driving the oscillator in the X-axis direction and the Z-axis direction to the driving portion; a detecting portion provided on the oscillator for detecting deflection of the oscillator during oscillation in the Z-axis direction; an angular velocity detection circuit for outputting an angular velocity signal by amplifying and detecting a signal output from the detecting portion when the driving signal is supplied from the first driving circuit to the driving portion and an angular velocity is input about a Y-axis; and a self diagnosis circuit for outputting a signal enabling failure diagnosis on the detecting portion by amplifying and detecting a signal output from the detecting portion when the driving signal is supplied from the second driving circuit to the driving portion, wherein: the oscillator is a tuning fork type oscillator made of an elastic material and having at least two arms and at least one base portion connecting the arms; the driving portion includes a piezoelectric film on which at least upper electrodes are spaced from each other across the center of at least one principal surface of at least one of the arms of the tuning fork type oscillator; the detecting portion includes a piezoelectric film provided on at least one principal surface of at least one of the arms of the tuning fork type oscillator and having an electrode on both sides thereof; driving signals which are inverted from each other in phase are supplied from the first driving circuit to the upper electrodes spaced from each other to cause tuning fork oscillation in the X-axis direction; and driving signals which are inverted from each other in phase and different in amplitude are supplied from the second driving circuit to the upper electrodes spaced from each other to cause tuning fork oscillation in the X-axis direction and oscillation also in the Z-axis direction.