Electroacoustic transducer with springs forming electrical

Abstract

An electroacoustic transducer in accordance with the present invention comprises a perforated backplate having a plurality of upstanding parallel ribs between which conductive surfaces are situated. The conductive surfaces are electrically interconnected with one another and with a contact surface on a relieved shoulder at one end of the backplate. This shoulder is engaged by a bifurcated contact spring that (1) electrically connects the conductive surfaces to the input of an integrated preamplifier circuit deposited on a substrate and (2) holds the substrate in place on the underside of the backplate. An electret diaphragm having a metallized surface is tensioned across the ribs of the backplate with the metallized surface facing away from the backplate, and while so tensioned, the ends of the diaphragm are clamped against the backplate by a conductive intermediate member that makes electrical contact with the diaphragm. The intermediate member is held in place by a conductive spring member that wraps around the sides of the foregoing assembly and presses the intermediate member and the substrate toward one another. The spring member provides the clamping force necessary to retain the desired tension on the diaphragm and at the same time further secures the substrate in place. In addition, the spring member includes a terminal that is located in engagement with the ground lead of the preamplifier circuit and thus in combination with the intermediate member provides a conductive path to ground for the conductive surface of the diaphragm. Finally, the spring member serves to provide additional electrostatic shielding for the electret.