PROBLEM TO BE SOLVED: To provide a capacitance-type acoustic wave transducer ensuring an excellent dielectric voltage with a transmission sound pressure and a sensitivity characteristic taken into consideration.SOLUTION: The capacitance-type acoustic wave transducer comprises a cell and voltage application means 15. The cell comprises: a first insulation film 7 and a second insulation film 9 arranged with a space 8 interposed therebetween and a first electrode 6 and a second electrode 10 arranged respectively outside the first insulation film and outside the second insulation film, the insulation films being arranged with a space interposed therebetween. The distance of the space changes as the second insulation film and the second electrode displace, thereby causing the capacitance between the first electrode and the second electrode to change. The voltage application means applies a voltage between the first electrode and the second electrode. The electric field strength applied to the first insulation film is closer to the electric field strength which causes insulation breakdown, compared with the electric field strength applied to the second insulation film.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2016,JPO&INPIT【課題】送信音圧や感度特性を考慮して、優れた絶縁耐圧が得られる静電容量型音響波トランスデューサを提供する。【解決手段】間隙8を挟んで配された第一の絶縁膜7及び第二の絶縁膜9と、間隙を挟んだ第一及び第二の絶縁膜の外側にそれぞれ配された第一の電極6及び第二の電極10と、を備え、第二の絶縁膜と第二の電極とが変位することで間隙の距離が変化し、これにより第一及び第二の電極間の静電容量が変化するセルと、第一の電極と第二の電極との間に電圧を印加する電圧印加手段15と、を有する静電容量型の音響波トランスデューサであって、第一の絶縁膜にかかる電界強度が、前記第二の絶縁膜にかかる電界強度に比して、絶縁破壊を生ずる電界強度に近くなるように構成した静電容量型音響波トランスデューサ。【選択図】図2
