Knowles Electronics, Inc.

Ernest L Lenzini

Timothy K Wickstrom

An electret microphone assembly, such as for a hearing aid comprises an electret microphone having a diaphragm and a charged plate, a substrate spaced from the charged plate, and a wire loop having first and second ends and a mid-portion. The first and second ends are secured to the substrate and the mid-portion is pressed against the charged plate. An amplifier is disposed on the substrate and has an input terminal coupled to the wire loop. Alternatively, an impedance matching circuit can be disposed on the substrate and coupled to the wire loop. A conductive bond containing silver particles further secures the wire loop mid-portion and the charged plate. In an alternative configuration the loop is dimensioned such that its mid-portion passes close to the charged plate without touching it. The conductive bond serves not only to form a rigid structure, but also serves as an electrical bridge to complete the circuit between the two elements. The first and second ends are wedge-bonded to the substrate, and the wire loop forms an angle of substantially 90.degree. with the substrate. A conductive track disposed on the substrate coupling the first and second ends. A method of manufacturing the electret microphone assembly is also disclosed.

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Elk Grove Village, IL, United States of America

Ernest L Lenzini