Multilayer piezoelectric copolymer transducers

Abstract

Process technology for fabricating multilayer transducers of piezoelectric polymers without the need of adhesive lamination has been developed. The technology is based on spin-coating of the piezoelectric copolymer poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)). A comparison between single- and multilayer transducers of the same dimensions fabricated using similar processing schemes has been performed with respect of generating ultrasound. Multilayer transducers become increasingly important in miniaturized systems, due to the low permittivity of the piezoelectric polymer material. Multilayer technology makes it possible to subject the polymer material to high electrical fields at low drive voltages, and also increases the capacitance of the transducers for impedance matching purposes. It has been shown that the multilayer transducers outperform similar single-layer transducers by 12 dB during pitch-catch measurements.