| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic transducer capable of performing highly effective acoustic emission, with a high waterproof pressure, a little decline in electro-acoustic transduction efficiency by water pressure, and a little directive variation in sound waves to be emitted. SOLUTION: A cylindrical active vibrating body 11 generates respiratory vibration at a cylindrical piezoelectric ceramic vibrator 11a by piezoelectric phenomenon. In the respiratory vibration, a diameter fluctuates uniformly with a unique frequency. Disk-like resonation boards 12 and 12 are formed at an aperture in both ends of the cylindrical active vibrating body 11 to seal the aperture, and the whole is covered with a sheath (or mold) 13. The disk-like resonation board 12 prevents inflow of external liquid to a cavity V and resonates to the respiratory vibration of the cylindrical active vibrating body 11 to generate diameter direction vibration of a phase and a magnitude identical to the respiratory vibration with a frequency identical to the unique frequency. Moreover, the quality of the material, the shape and the dimension for the disk-like resonation board 12 are established so as to cope with the phase and the magnitude of the respiratory vibration and the frequency identical to the unique frequency. COPYRIGHT: (C)2010,JPO&INPIT
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