| 摘要 |
PROBLEM TO BE SOLVED: To obtain a drip-proof type ultrasonic microphone capable of short- distance detection by preventing the excitation of a plus lead which causes an increase reverberation time. SOLUTION: The drip-proof type ultrasonic microphone is constituted by arranging a disk-like piezoelectric ceramics 2 on the inside surface of the bottom part of a bottomed cylindrical shape vibration case 1, bringing the vibration case 1 into contact with the lower surface of the piezoelectric ceramics 2, erecting a lead 3 on the upper surface of the piezoelectric ceramics 2 and surrounding the outer peripheral part of the piezoelectric ceramics 2 with a ring silicon 4 of elastic body which is fixed to the inner peripheral part of the vibration case 1. In this case, a projection part 4b which comes into contact with an exposed part (3a) of the lead 3 led out of the piezoelectric ceramics 2 is successively provided on the inner peripheral surface 4a of the ring silicon 4.
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