Electret condenser microphone

An electret condenser microphone for receiving an acoustic wave to be converted to an acoustic signal indicative of said acoustic wave, comprising:

• a casing member having a center axis passing therethrough, said casing member including a circular inlet portion, and a cylindrical side portion integrally formed with said inlet portion of said casing member, said side portion of said casing member having a first section close to said inlet portion of said casing member, and a second section remote from said inlet portion of said casing member, said second section of said side portion of said casing member being radially inwardly bent toward said center axis of said casing member;
• a printed circuit board in the form of a circular shape and disposed in said casing member to be held in contact with said second section of said side portion of said casing member, said casing member and said printed circuit board collectively forming a cylindrical casing space;
• an electrode plate accommodated in said casing space of said casing member;
• an electrically insulating member in the form of an annular ring shape and accommodated in the casing space of the casing member to be held in coaxial alignment with the casing member;
• a plurality of electrically connecting members each intervening between said printed circuit board and said electrode plate to have said printed circuit board and said electrode plate electrically connected with each other, said electrically connecting members being partly retained by said electrically insulating member and disposed on and along the circumference of said printed circuit board to be equidistantly spaced apart from one another;
• and
• a diaphragm located between said inlet portion of said casing member and said electrode plate to be spaced apart along said center axis of said casing member from said electrode plate at a predetermined space distance.