| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic sensor, for performing transmission and reception which facilitates handling such as positioning, installation, and the like, while having proper radiation intensity or reception sensitivity of ultrasonic waves. SOLUTION: An ultrasonic sensor 10 for transmitting/receiving ultrasonic waves includes a piezoelectric element 11 including a thin portion 12 of thickness Ta and a thick portion 13, integrated with the thin portion 12 and having a thickness Tb larger than that of the thin portion; thin portion electrodes 17 holding the thin portion 12 therebetween; and thick portion electrodes 18 holding the thick portion 13 therebetween. The piezoelectric element 11 brings the thickness Ta of the thin portion 12 and the thickness Tb of the thick portion 13 into a relation such that a resonant frequency fra in the thin portion 12 and an anti-resonant frequency fab in the thick portion 13 become equal. COPYRIGHT: (C)2010,JPO&INPIT
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