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:
Sep. 04, 2007
Filed:
Nov. 30, 2004
Applicant:
Shiro Tsuda, Asahi, JP;
Inventor:
Shiro Tsuda, Asahi, JP;
Assignee:
Ferrotec Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H04R 25/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
An audio speaker includes a driver unit having a magnetic pole case defining a radial gap, a vibration system having a diaphragm and a voice coil where the vibration system is fixed to the drive unit and the voice coil is movably mounted into the radial gap, and a residual magnetic fluid layer disposed on the surfaces of one or more of the magnetic pole case and the voice coil where an air gap exists between the voice coil and the magnetic pole case.