CONDENSER TYPE MICROPHONE

摘要

PURPOSE:To obtain needed and sufficient sensitivity with no edge effect by using a nonporous fixed electrode smaller in diameter than an effective vibration part and by forming an air room extending from the external part of a fixed part to a part under the end part of the electrode. CONSTITUTION:Fixed electrode 17 is set properly on pedestal 16c by making use of the elastic effect for fixed piece 16b of fitting structure 16; and electrode 17 is smaller in diameter than the effective vibration part of diaphragm 15 and fixed electrode 17 itself has no air hole. A fixed gap provided between fixed electrode 17 and diaphragm 15 is set by a difference in height between circumference part 16a and pedestal 16c of fitting structure 16, but the need to use a spacer for obtaining the fixed gap in the usual manner is eliminated and on the bottom of structure 16, air hole 16e for obtaining unidirectivity is formed extending to cavity part 16d. Consequently, needed sensitivity can be obtained without edge effect.