Study On Piezoelectric Transducer For Medical Ultrasonic Imaging

Piezoelectric effect and inverse piezoelectric effect of the piezoelectric material can convert electric power between mechanic energy. Piezoelectric material driven by high-frequent electric signal vibrates at high frequency and generates ultrasonic wave, while it transforms the ultrasonic wave into electric signal when it receives ultrasonic wave. Medical ultrasonic imaging can be realized by this way. Main research in this paper includes:1. PZT-PMN piezoelectric ceramic was produced by conventional solid synthesis.。By doping Sr, Ni, and La to substitute the A or B place in perovskite structure, properties of piezoelectric material can be improved. Results shows when the amount of NiO is 0.1 wt% and La2O3 is 0.7 wt%, the sample sintered at 1230℃performs best properties. The dielectric constantεr is 4264,dielectric loss Tanδis 2.08%,and piezoelectricity d33 is 641 PC/N。2. 0-3 piezoelectric composite was studied using casting and hot-press. This research is aimed at manipulate piezoelectric material with low sonic acoustic resistance Results indicates when the volume ratio of ceramic powder is 60%, the piezoelectricity d33 of the composite reaches 43 PC/N and dielectric constant is above 200. Acoustic resistance is below 14 MRayls much smaller than the ceramic.3. Pluse-echo impulse response of piezoelectric ultrasonic transducer was studied by theoretical analysis and software simulation. Focus of the research is on the effect of match layer. Results shows when acoustic resistance of the match layer is 6 MRayls and thickness is 0.25λ, Pulse-echo impulse response gives the best amplitude 0.0035 and bandwidth (-6 dB) is about 50% of the center frequency (3 MHz).4. After the analysis on the effect of piezoelectric ultrasonic transducer parameters on the performance of device, the route for designing was worked out. Ultrasonic transducer was produced by a certain process.