| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ultrasonic sensor in which reverberation vibration is suppressed and an influence of sub-resonance points other than main vibration can be suppressed without employing a damping member. SOLUTION: The ultrasonic sensor 1 comprises a case 4 having a vibrator section 5, and a piezoelectric vibration element 2 abutting against the vibrator section 5 and vibrating the vibrator section 5 in the case 4. The vibrator section 5 has an elongated rectangular or elliptical vibration plane. The piezoelectric vibration element 2 has outline similar to the vibration plane of the vibrator section 5 and substantially same size as that of the vibration plane of the vibrator section 5. Since the outline of the piezoelectric vibration element 2 is similar to the vibration plane of the vibrator section 5, a profile of the piezoelectric vibration element 2 is increased, and reverberation vibration is suppressed by preventing capacitance of the piezoelectric vibration element 2 from decreasing. Since the vibration plane of the vibrator section 5 and the outline of the piezoelectric vibration element 2 have an elongated shape, the influence of sub-resonance points other than main vibration on the vibrator section 5 is suppressed without employing a damping member. COPYRIGHT: (C)2006,JPO&NCIPI
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