| US 7,590,252 B2 | ||
| Heat-resistant electret condenser microphone | ||
| Katsuhiro Makihata, Kanagawa (Japan); Hiroshi Ogura, Tokyo (Japan); and Yoshinobu Yasuno, Kanagawa (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Appl. No. 10/589,281 PCT Filed Aug. 04, 2005, PCT No. PCT/JP2005/014333 § 371(c)(1), (2), (4) Date Aug. 11, 2006, PCT Pub. No. WO2006/013940, PCT Pub. Date Feb. 09, 2006. |
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| Claims priority of application No. 2004-230407 (JP), filed on Aug. 06, 2004. | ||
| Prior Publication US 2007/0160247 A1, Jul. 12, 2007 | ||
| Int. Cl. H04R 25/00 (2006.01) | ||
| U.S. Cl. 381—174 [381/91; 381/178; 381/369] | 12 Claims |
| 1. An electret condenser microphone comprising:
a vibrating diaphragm in which one face is electrically conductive;
a fixed electrode which is placed to be opposed to said vibrating diaphragm via an air layer;
a dielectric layer which becomes an electret for storing charges in one of said vibrating diaphragm and said fixed electrode;
circuit means for converting an electrostatic capacity between said vibrating diaphragm and said fixed electrode to an electric
signal;
external connecting means for leading out the electric signal; and
a first spacer which forms and holds a predetermined positional relationship between said vibrating diaphragm and said fixed
electrode, said microphone being incorporated in a metallic case while exposing said external connecting means, wherein
an outer face of said case is coated by a nonmetallic material in which a deforming temperature is higher than a charge dissipating
temperature of said dielectric layer that becomes said electret.
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