Optimised properties of high frequency transducers based on curved piezoelectric thick films obtained by pad printing process

Abstract

A high frequency transducer for medical imaging (25 MHz) was fabricated using a pad printing process to deposit a curved lead zirconate titanate (PZT) thick film on electroded backing (porous PZT). This piezoelectric thick film was characterised, and a thickness coupling factor (47%) comparable with that of a bulk ceramic with similar composition was measured. This transducer was successfully modelled with a numerical tool previously published and specifically adapted to curved shapes. The experimental axial and lateral resolutions are 40 and 230 μm respectively. Moreover, the sensitivity is sufficiently high to consider this transducer to be integrated in an echographic system for high frequency imaging such as skin.