Construction and Performance of an Experimental Phased Array Acoustic Imaging Transducer

Abstract

A technique for electrically connecting to the PZT elements in a phased array transducer of a cardiac imaging probe is described. The transducer is a stack consisting of a PZT substrate with metallized faces and is bonded to an acoustic absorber across a thin alumina substrate of proper acoustic impedance. The PZT substrate is sawed into an array of elements and a metal foil with an integrally moulded acoustic lens is bonded to the tops of the elements to form the common ground connection. The transducer stack is enclosed in an alumina box and the electrical connection to the PZT elements is made by silk-screened metallic conductors on the sides of the box. The stack transducer module is enclosed in a two part linen bakelite case which is sealed by injecting silicone rubber. A technique that was used to prepare the surface of the acoustic absorber, which resulted in wide bandwidth transducers, is described. Finally, we show the pulse-echo response of the completed transducer imaging a point target in water.