ASA 127th Meeting M.I.T. 1994 June 6-10

2pEA7. Piezoelectric composite transducers.

Leslie Bowen

Richard Gentilman

Hong Pham

Daniel Fiore

Materials Systems, Inc., 521 Great Rd., Littleton, MA 01460

Piezoelectric ceramic/polymer composites have found increasing use in high resolution medical ultrasound systems and advanced Navy underwater acoustic applications. Composite transducers offer design versatility and performance advantages over monolithic piezoelectric ceramic and monolithic piezoelectric polymer devices under both sensing and actuating conditions. In particular, composite transducers allow improved acoustic impedance matching to water and body fluids, improved lateral mode cancellation, enhanced thickness mode coupling coefficient, and naturally broad bandwidth. However, applications for these versatile transducers have been limited by the difficulties of cost-effectively manufacturing the arrays of fine PZT ceramic elements required for composite assembly. At Materials Systems, Inc., ceramic injection molding has been developed into a viable net-shape process for making complex-shaped, fine scale PZT 1-3 and 2-2 transducer element arrays. This presentation describes the injection molding approach for manufacturing piezocomposite transducers, and reviews the sensing and actuating performance of injection molded 1-3 transducers over the frequency range 1 kHz to 5 MHz. [This work is funded by ONR.]