ELECTRET CONDENSER MICROPHONE

摘要

PROBLEM TO BE SOLVED: To improve the sensitivity and SN ratio of an electret condenser microphone whose rear electrode is formed of a metal material in a cup shape. SOLUTION: On the circumferential surface of a cylinder part of the rear electrode formed of the metal material in the cup shape, at least three or more projections 18B are provided at equal intervals in the circumferential direction and crestal surfaces of the projections are made to abut against the internal wall surface of the cylinder part of a capsule to form a gap G between the cylinder part 18A of the rear electrode 18 and the internal wall of the capsule 11; and the gap G is thus formed to separate the cylinder part of the rear electrode from the internal wall of the capsule 11 and then the value of floating capacity generated between them is decreased to improve the sensitivity. COPYRIGHT: (C)2005,JPO&NCIPI