| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an ultrasonic sensor capable of suppressing the deterioration in transmission/reception sensitivity due to temperature change. Ž<P>SOLUTION: An ultrasonic sensor 10 includes a circuit device 20 for applying a voltage for oscillating ultrasonic wave to the laminated piezoelectric element 16 of a transmitting device 11. The circuit device 20 detects a resonance frequency fc common to the acoustic matching member 13 of the transmitting device 11 and the acoustic matching members 13p of respective receiving devices 12p-12r. The circuit device 20 adjusts the frequency of the voltage to be applied to the laminated piezoelectric element 16 to be equal to the resonance frequency fc. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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