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:
Jan. 10, 1989
Filed:
Dec. 04, 1987
Applicant:
Inventor:
Susumu Katayama, Osaka, JP;
Assignee:
Matsushita Electric Works, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04R / ;
U.S. Cl.
CPC ...
181142 ; 181165 ; 181171 ; 340391 ;
Abstract
An electrostatic transducer which includes a vibrating membrane provided between a fixed electrode and a movable electrode to which electric signals are applied. The transducer further includes a plurality of depressions provided concentrically with a center of the fixed electrode in a surface of the fixed electrode which is in contact with the vibrating membrane and a plurality of through openings corresponding with the plurality of depressions further provided in the fixed electrode whereby the resonant frequency of the electrostatic transducer is reduced and the conversion efficiency of electric signals to sound pressure is increased.