Abstract: An electro-mechanical transducer having a first layer made of piezoelectric material having opposing major surfaces, a pair of electrodes formed on the major surfaces of the first layer, respectively, and a second layer clamped at its one surface to one of the surfaces of the first layer. In this case, the first layer has a Young's modulus of E, the second layer has a Young's modulus of Ex in one direction and a Young's modulus Ey in the direction perpendicular to the one direction in the major surface, The Young's moduli E, Ex, Ey satisfy the relation E>Ey, Ex>Ey, and one end of the first and second layers along the one direction is clamped.

Abstract: An improved method for making a backplate assembly for an electret transducer used in a microphone wherein a synthetic resin film such as polytetrafluoroethylene or fluorinated ethylene-propylene copolymer is attached to a plate member having a flat conductive surface and which has been heated so as to securely attach the film thereon and charging said synthetic film to form an electret.