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. 20, 1987
Filed:
Mar. 11, 1985
Dean W Flygstad, Apple Valley, MN (US);
Craig E Tromborg, Bloomington, MN (US);
Telex Communications, Inc., Minneapolis, MN (US);
Abstract
An electret transducer is comprised of a motor and signal processing apparatus, that may include an amplifier and/or impedance matching means, disposed within a sealed conductive housing. The motor is fabricated in place within a housing and the signal processing means is mounted on the underside of the cover for the housing so that each may be independently tested prior to combining into a unitary structure. The motor is comprised of easily fabricated and assembled components that include means for spacing a backplate from the walls of the conductive housing and a spacer intermediate the backplate and the center of a diaphragm. The backplate and the diaphragm are provided with registering apertures. The amplifier is mounted to the cover to conductively connect to the housing and to provide rigid outwardly extending terminals for ready connection to further electrical circuits, as in a hearing aid. The component parts of the transducer are fabricated by half etching through the use of etching resist patterns that are placed in registering cooperative disposition on the surfaces of a flat sheet of material of which the components are comprised, to provide variations in thickness of predetermined portions of the finished components.