| 摘要 |
<P>PROBLEM TO BE SOLVED: To stably provide a high acoustic resistance which is required for a pressure equivalence in a non-directional capacitor microphone unit. <P>SOLUTION: The non-directional capacitor microphone unit includes a diaphragm 8 whose peripheral edge is attached to a diaphragm holder 4, and a fixed electrode 6, made of metal material, which is arranged to face the diaphragm across a predetermined interval through a spacer 5 which is electrically insulating, with a rear space of the diaphragm being closed. At a portion of the fixed electrode 6 that contacts to the spacer 5, a groove 16a which is concave and has a bottom is formed by etching so that the rear space between the diaphragm and the fixed electrode communicates with the outside. The communication part formed between the groove 16a and the spacer 5 is utilized as an acoustic resistance for pressure equivalence. <P>COPYRIGHT: (C)2013,JPO&INPIT |
