| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic sensor which can obtain desired frequency characteristics with good repeatability while a miniaturization is attained. SOLUTION: A hydrophone element 1 is a hydrophone element of electrostatic capacity type in which a backing-plate pat 14 is formed through a spacer part 13 to the rear surface side of a diaphragm-like vibration cone part 12 formed continuously integrally inside a frame-like supporting section 11. A sound hole 51 is formed in the front wall 5a which counters the vibration cone part 12 of the hydrophone element 1 in a shielding case 5, sealing between the mutual opposite sides of the circumferential part of a microwave transmission circuit device board 4 and the supporting section 11 of the hydrophone element 1 is performed, the sealing between the mutual opposite sides of the circumferential part of the microwave transmission circuit device board 4 and the circumferential part of the printed circuit board 2 is performed. A vent hole 26 which sets an acoustic impedance between the back rooms 6 made of the space surrounded by the hydrophone element 1, the microwave transmission circuit device board 5, and the printed circuit board 2 is provided to the printed circuit board 2. COPYRIGHT: (C)2007,JPO&INPIT
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