Patterning of 30MHz ultrasonic Fresnel zone plate by laser poling of PVDF-TrFE film

Abstract

This paper describes a novel approach to construct Fresnel zone plate (FZP) transducers by laser poling of poly vinyliden fluoride-co- trifluoroethylene films. The patterning of polarization was confirmed by measurement of pyroelectricity current. After this confirmation, the transducer was driven in the water bath and the spatial distribution of the sound pressure was measured. The directivity of the transducer was compared to the flat and concave transducers of same aperture size.