JPH0334811B

PURPOSE:To make possible the detection of oscillation in many directions by a single element possible by providing a cut-out in the vicinity of the center of a piezo-electric element obtained by bonding two planar piezo-electric elements fixed at the periphery and having axes of polarization in the thickness direction. CONSTITUTION:For the oscillation in the thickness direction of a bending oscillator 3, electric charges having the same polarity are produced in electrodes 3a, 3b, 3c and electrodes 3a', 3b' and 3c' so that a potential difference is not produced at terminals 5 and 6. However, a signal proportionating to the acceleration of the oscillation in the direction of thickness is produced in terminals, 7, 8 having upper and lower side electrodes 3b, 3b' of the flexible vibrator 3 as output take-out electrodes. As to a transverse oscillation, electric charges of the same polarity are produced in the electrodes 3a, 3a' and a potential difference is produced in terminals 5, 6 to produce signals proportionating to the transverse acceleration of oscillation, since same charges having polarities different from electrodes 3a, 3a' at electrodes 3c, 3c' are generated. Signals are not produced in terminals 7, 8 because the charges of the same polarity are produced in the electrodes 3b, 3b'. In such a manner, the upper and lower side electrodes of the bending oscillator 3 is divided into three portions, thereby two directional oscillation can be detected by the same bending oscillator to minimize a device size.