Improved fabrication of focused single element P(VDF-TrFE) transducer for high frequency ultrasound applications

Abstract

We present an improved fabrication technique for the focused single element poly (vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) transducer. In this work, a conductive epoxy for a backing layer was directly bonded to the 25 mu m thick P(VDF-TrFE) film and thus made it easy to conform the aperture of the P(VDF-TrFE) transducer. Two prototype focused P(VDF-TrFE) transducers with disk-and ring-type aperture were fabricated and their performance was evaluated using the UBM (Ultrasound Biomicroscopy) system with a wire phantom. All transducers had a spherically focused aperture with a low f-number (focal depth/aperture size = 1). The center frequency of the disk-type P(VDF-TrFE) transducer was 23 MHz and -6 dB bandwidth was 102%. The ring-type P(VDF-TrFE) transducer had 20 MHz center frequency and -6 dB bandwidth of 103%. The measured pulse echo signal had reduced reverberation due to no additional adhesive layer between the P(VDF-TrFE) film and the backing layer. Hence, the proposed method is promising to fabricate a single element transducer using P(VDF-TrFE) film for high frequency applications. (C) 2012 Elsevier B.V. All rights reserved.