An ultrasonic transducer apodized by polarization

In attempting to improve the quality of images produced by ultrasonic diagnostic equipment, the authors tried to narrow the width of the ultrasound beam in the scanning direction and the short axis perpendicular to the scanning direction, and to shorten the pulse duration. The beamwidth, especially in the short axis, is markedly broad. To narrow the width, the transmitting acoustic sound pressure was apodized by polarizing the piezoelectric ceramic element of an array-type transducer in a stepped manner. A transducer using this apodization had its beamwidth decreased from 50% to 80% compared to the conventional transducer