| 摘要 |
An acceleration sensor (10) includes a vibrator (12) of, for example, a quandrangular prism shape. On the opposed side faces of the vibrator, piezoelectric elements (14,16) are formed. The piezoelectric elements (14,16) are polarized from the outside toward the vibrator side. Driving signals of the same phase are applied to these piezoelectric elements (14,16). The vibrator (12) vibrates in its longitudinal direction by these driving signals. In the vibrator (12), a resonance frequency of the longitudinal vibration is equalized to a resonance frequency of the bending vibration. And, a voltage difference between the output voltages of the two piezoelectric elements (14,16) is detected by a differential circuit. The shape of the vibrator (12) may be a triangular prism shape. In this case, the piezoelectric elements are formed on the three side faces of the vibrator (12). Two by two combinations of these piezoelectric elements are inputted to the differential circuits. The piezoelectric elements (14,16) may be polarized from the vibrator side toward the outside. <IMAGE> |
