PIEZOELECTRIC TRANSDUCER HAVING PROTUBERANCES FOR TRANSMITTING ACOUSTIC ENERGY AND METHOD OF MAKING THE SAME

摘要

A method of forming an ultrasound transducer having thermoformed protuberances (16) comprises providing a substrate (20) having a plurality of perforations (22) of a given dimension. The perforations or apertures (22) are formed in the substrate (20) and operate to determine the resonance frequency associated with the transducer. A film of polymeric material (10), capable of showing piezoelectric properties when strained in its plane and electrically biased by a field applied in a direction normal to its faces, is then laminated onto the substrate (20). The film (10) is heated to a given temperature and a pressure differential is applied between the top and bottom surfaces of the film (10) for a sufficient time to form protuberances (16) in the film through the apertures (22) in the substrate (20). The film (10) is then cooled to a given ambient temperature while maintaining a pressure differential between the top and bottom surfaces of the film (10) for a sufficient time until the ambient temperature is reached so as to cause the protuberances (16) to maintain a substantially permanent curvature.