| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic sensor capable of measuring vibration characteristics etc., of a vibration electrode plate from the side of a counter electrode plate without deteriorating sensor sensitivity much. SOLUTION: An electrostatic capacity type acoustic sensor is constituted in such a way that the vibration electrode plate 24 sensing sound pressure faces the counter electrode plate 25. A sound hole 31 for passing vibrations is formed in the counter electrode plate 25. The sound hole formed in the counter electrode plate 25 comprises a plurality of sound holes 31 of relatively small opening area and a single sound hole 36 of relatively large opening area, and the sound holes 31 and 36 are disposed in a lattice shape at regular intervals. Further, the sound hole 36 of large opening area is provided in the opposite electrode plate 25 within a circular area (a) having its center opposed to the center of a diaphragm 28 and also having a radius r=L/4, where L is the width of the diaphragm 28. COPYRIGHT: (C)2009,JPO&INPIT
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