ELECTRET-CONDENSER MICROPHONE

摘要

An electret-condenser microphone according to the present invention includes a vibrating diaphragm 33 and a back electrode 35 which compose a condenser; a cylindrical case 31 which houses the vibrating diaphragm 33 and the back electrode 35; a circuit board 39 which is housed in an opening 31 c of the cylindrical case 31, is fixed to the opening 31 c by crimping a crimp edge 31b formed by bending an opening end of the cylindrical case 31 inward, and covers the opening; and a substrate 51 fastened to an outer surface of the circuit board 39. A circular pattern 44 and annular pattern 45 are formed on the outer surface of the circuit board 39 and a circular pattern 52 and annular pattern 53 are formed on that surface of the substrate 51 which is farther from the circuit board 39. The circular pattern 44 and annular pattern 45 are connected with the circular pattern 52 and annular pattern 53 via thru-holes 54a and 54b in the substrate 51, and that surface of the substrate 51 on which 52 and 53 are formed serves as a reflow-soldering surface.