An ultrasonic transducer for second imaging using a LiNbO/sub 3/ plate with a local ferroelectric inversion layer

A new lithium niobate (LiNbO/sub 3/) transducer of separated transmitter-receiver configuration is proposed for application to second harmonic imaging in a high-frequency range. In this transducer, a domain-inverted layer of half the plate thickness is formed selectively by Ti-diffusion and heat treatment in the central part of a LiNbO/sub 3/ plate. The uniformly polarized surrounding region is used as the transmitter that will generate the fundamental wave component. A transducer with the transmission frequency of 50 MHz and the reception frequency of 100 MHz is fabricated using a 36/spl deg/ rotated Y-cut LiNbO/sub 3/ plate, and its performance is demonstrated.