| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a small acoustic sensor excellent in reliability. <P>SOLUTION: A small acoustic sensor includes a cup-shaped back electrode 18 formed of a metal material, and an electret dielectric film 19 formed on the outer surface of the cup-shaped back electrode 18. An insulation layer 18a is formed on at least the outer surface of the cup-shaped back electrode 18 by anodization or chemical conversion. The metal material is aluminum, titanium or magnesium. The electret dielectric film 19 is an electret-converted film consisting of tetrafluoroethylene hexafluoropropylene copolymer, polytetrafluoroethylene, tetrafluoroethylene perfluoro alkyl vinyl ether copolymer, or tetrafluoroethylene perfluoro methyl vinyl ether. <P>COPYRIGHT: (C)2013,JPO&INPIT |
