Abstract

A method of forming an ultrasound transducer having thermoformed protuberances comprises providing a substrate having a plurality of perforations of a given dimension. The perforations or apertures are formed in the substrate and operate to determine the resonance frequency associated with the transducer. A film of polymeric material capable of showing piezoelectric properties when strained in its plane and electrically biassed by a field applied in a direction normal to its faces, is then laminated onto the substrate. The film is heated to a given temperature and a pressure differential is applied between the top and bottom surfaces of the film for a sufficient time to form protuberances in the film through the apertures in the substrate. The film is then cooled to a given ambient temperature while maintaining a pressure differential between the top and bottom surfaces of the film for a sufficient time until the ambient temperature is reached so as to cause the protuberances to maintain a substantially permanent curvature.