Linear electronic scanning type of ultrasonic imaging system using comb electrode arrays with Fresnel zone pattern

Abstract

A linear electronic scanning type of ultrasonic imaging technique using comb electrode arrays is described. The comb arrangement of electrodes is mounted on one surface of a thin piezoelectric ceramic plate, which makes the development of the scanning resolution easier in comparison with the use of conventional array transducer elements. The region between the comb electrode and the counter electrode operates as an equivalent thickness-mode vibrator. The comb electrode arrays are used to construct the Fresnel zone pattern. A longitudinal wave is effectively radiated into water via an acoustic lens. The point focusing of the sound beam is realized by the agreement of two orthogonal focal positions. We demonstrate ultrasonic imaging results for several samples using the present transducer.