Patent ID: 7991173
Filing Date: 2011-08-02
Classification: H04R

Abstract:
1. A waterproof microphone comprising: a cylinder-shaped case having an anterior wall; and a first diaphragm, a second diaphragm and an electrode plate which are disposed in the case in sequence from an anterior wall side toward a rear side, wherein an anterior chamber is formed between the anterior wall and the first diaphragm, a first gap is formed between the first diaphragm and the second diaphragm, a second gap is formed between the second diaphragm and the electrode plate, a posterior chamber is formed behind the electrode plate, a conversion module is housed in the tosterior chamber, where in the conversion module equalizes an impedance of a sound pressure-electrical signal generated by the second diaphragm and electrode plate with an impedance of an external circuit, the first gap, the second gap and the posterior chamber are linked by air passages in the second diaphragm and the electrode plate, the first gap is sealed from the anterior chamber by the first diaphragm, and the anterior wall has a discharge aperture overlapped with an inner face of the anterior chamber, and a back plate disposed behind the electrode plate and in front of the posterior chamber in the case, wherein the back plate has an air hole linking the posterior chamber and an outside of the case, and the air hole is one of the air passages.