| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that an inexpensive ultrasonic wave transmitting/receiving apparatus which uses a bottomed cylindrical case made of a molding resin such as epoxy resin does not spread since noise resistance is low and the operation of a back sensor system becomes unstable. SOLUTION: The ultrasonic wave transmitting/receiving apparatus has its bottomed cylindrical case made of the resin having such conductivities that the resistance value is 1/1,000 to 10 times as large as resonance impedance. Consequently, the ultrasonic wave transmitting/receiving apparatus which is inexpensive and has nearly the same or higher performance of sound pressure sensitivity etc., than before and also has high noise resistance can be provided to the market. COPYRIGHT: (C)2009,JPO&INPIT
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