Patent ID: 7171012
Filing Date: 2007-01-30
Classification: H01G,H04R

Abstract:
1. An electret condenser microphone comprising: a condenser section that comprises: a capsule accommodating said condenser section therein, said capsule having a side wall and a cover board affixed to a surface of said back electrode board facing away from the diaphragm so that said cover board and said back electrode board form a complex front board arrangement for the microphone; wherein said back electrode board has a first through-aperture formed therethrough to communicate at on one end thereof to the gap space between the diaphragm and the back electrode board; said cover board has a second through-aperture formed therethrough which communicates an one end thereof to an outside of said electret condenser microphone, and is positioned so as not to be in alignment with the first through-aperture with a distance therebetween which is longer than either thickness of the back electrode board and the cover board; and said complex front board arrangement has a connecting path at an interface including opposing surfaces of said cover board and said back electrode board, wherein the connecting path extends perpendicularly to axes of said first and second through-apertures and is connected to the first and second through-apertures; whereby said electret film communicates with the outside through said connecting path and said first and second through-apertures, and an ingress of grit from the outside to said electret film is suppressed by said connecting path.