Diaphragm unit of a condenser microphone, a method of fabricating the same, and a condenser microphone

Abstract

This invention provides a condenser microphone simply constructed without using a separately provided push-up cylinder that has hitherto been used for pressing the vibration diaphragm to give a predetermined tension thereto. In this microphone, furthermore, the tension of the vibration diaphragm is hardly affected by a change in the temperature. A vibration diaphragm (15) subjected to a predetermined tension is held between a first ring (37) and a second ring (39), and then welded together to constitute a diaphragm unit (55). Preferably, a ring-like protuberance (39a) is provided on one ring to bias the vibration diaphragm (15) toward the other ring. The condenser microphone is assembled using the diaphragm unit (55) in such a manner that an insulating plate (23) for holding a back electrode (22) is engaged with said one ring.