P1M-2 Development of Miniature Ultrasonic Probe with PZT Film Deposited by Hydrothermal Method

Recently, the PZT poly-crystalline film deposited on titanium substrate by hydrothermal method has been studied actively for development of a small actuator and ultrasonic sensor in our laboratory. The PZT poly-crystalline films were deposited on a titanium substrate in KOH solution used as mineralizer which included Pb ion, Ti ion, and Zr ion under high temperature (about 150degC) and high pressure (about 4 kPa). We reported on the needle type miniature hydrophone and the ultrasonic transducer with hydrothermally synthesized PZT poly-crystalline films in 2005 IEEE International Ultrasonics Symposium in Rotterdam. It has confirmed that the hydrothermally synthesized PZT poly-crystalline films showed wide band frequency characteristics in MHz band of the sensitivities. It is thought that miniature ultrasonic probe with wide frequency band characteristics of sensitivities can be fabricated by using the hydrothermally synthesized PZT poly-crystalline films. The miniature ultrasonic probes were fabricated by hydrothermally deposited PZT poly-crystalline film on an end of the titanium wire with diameter of 0.6 mm and length of 50mm. The performances of trially fabricated ultrasound probes were measured. Ultrasonic imaging experiments using a target in water were performed with the trially fabricated ultrasonic probe with hydrothermally synthesized PZT films. As a result, it was confirmed that this probe has a center frequency of 16 MHz, a bandwidth of 80%, and distance resolution more than 80 micrometers. We will report about the structure and performance of the fabricated ultrasound probe with hydrothermally synthesized PZT poly-crystalline film and the results of imaging experiments under water