The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 06, 2012
Filed:
Nov. 09, 2006
Hiroyuki Takewa, Osaka, JP;
Hiroyuki Takewa, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An electro-acoustic transducer includes a diaphragm, a casing which is formed with an opening for directly or indirectly supporting the diaphragm, a first magnetic pole section provided on a side of the opening with respect to the diaphragm and having a magnetic pole at a surface which faces the diaphragm, a second magnetic pole section provided on a side of an inner bottom surface of the casing with respect to the diaphragm and having a magnetic pole at least a part of a surface which faces the first magnetic pole section through the diaphragm, and a drive coil provided on the diaphragm and located in a magnetic gap formed by the first and second magnetic pole sections. The magnetic poles of the first and second magnetic pole sections which face each other through the diaphragm have the same polarity. An outer shape of the surface of the first magnetic pole section which faces the diaphragm is smaller than that of the surface of the second magnetic pole section which faces the diaphragm.