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:
Oct. 02, 2000
Filed:
Jul. 21, 1996
Applicant:
Inventor:
Andrew Dames, Cambridge, GB;
Assignee:
Microtronic A/S, Roskilde, DK;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
310322 ;
Abstract
An electroacoustic transducer comprises a pair of active piezo electric membranes and a sleeve closed at its ends by the membranes to a form an enclosed rear volume of air. A case accomodates the assembly of sleeve and membranes and provides an enclosed front volume of air between its inner wall and the assembly. An opening in the case to the outside forms a sound pressure output. Each membrane comprises a sandwich of two active piezo layers on a substrate material. Very small thicknesses of the substrate and active piezo layers provides for a correct impedance match to the acoustic load in the ear when used in hearing aids.