An ultrasonic transducer for providing a desired sound field

摘要

A substantially gauss-shaped sound field is produced by an ultrasonic transducer, the potential on one side of the transducer being varied continuously by means of a thick-film electrode applied in a uniform or varying thickness. The thick-film can be a resistance paste 2 or a conductive paste 3 applicable in different thicknesses onto selected portions of the surface in question. The resistance paste can for instance be trimmed to different resistance values on selected portions of the surface. Such a technique makes it possible to alter the distribution of the potential so as to vary the distribution of the pressure in the sound field in such a manner that for instance a substantially gauss-shaped sound field is obtained. ……