SIMULATION AND FABRICATION PROCESS FOR A MEDICAL PHASED-ARRAY ULTRASONIC PROBE USING A 0.91PB(ZN1 3NB2/3)O-3-0.09PBTIO(3) SINGLE-CRYSTAL/

Medical array ultrasonic probes using a 0.91 Pb(Zn-1/3 Nb-2/3)O-3 -0.0 9PbTiO(3) (PZN-PT) single crystal exhibiting a high electromechanical coupling factor (k(33)) > 90% have been studied in order to realize bo th a higher sensitivity and broader bandwidth properties. Pulse echo c haracteristics of the array probes, each transducer of which has dimen sions of 6.0 mm x 0.14 mm with a center frequency of 3.5 MHz, are simu lated using the dielectric and the piezoelectric constants of the grow n PZN-PT single crystals. Simulated echo amplitudes of the PZN-PT prob es have been improved by as much as 7 dB compared with those of the co nventional Pb(Zr1-xTix)O-3 (PZT) ceramic ones. Moreover, the bandwidth of the PZN-PT probe is expected to be about 25% broader than those of the conventional PZT probes. It has been shown by simulation that the low acoustic impedance as well as the high coupling factor of the PZN -PT crystal contribute in broadening the bandwidth of the probe. The f abrication process of the array probe was investigated. A conventional method in which the dicing conditions are optimized and a novel dicin g process are proposed.