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