Convertor arrangement with varying focal width esp for medical imaging using multiple focus ultrasonic lens

摘要

The convertor arrangement has a convertor (12) with an acoustic side. It also has a focusing element (10) with a first and a second end. The focusing element (10) is positioned over the acoustic side. The focusing element (10) has a non-uniform radius of curvature. The focusing element (10) is effective to vary the focal length of the convertor arrangement. Preferably, the first end of the arrangement has a first radius of curvature and the second end has a second radius of curvature larger than the first. The focusing element (10) may also have a middle section with a radius of curvature smaller than those of the two ends. The convertor (12) may have element lengths and the focusing element (10) may have desired lengths, where the element lengths are adapted to the desired lengths of the focusing element (10).