Focusing mechanism for an ultrasound device

Claim 1

In focusing mechanism for a medical Doppler ultrasound device having first transducer means for transmitting ultrasound waves into the body toward internal body matter spaced from such transducer means and second transducer means for receiving at least some of the transmitted ultrasound waves reflected from such internal body matter, the first and second transducer means being positioned in closely adjacent relationship with a space therebetween and having respective planar outer transmitting and receiving faces, the improvement comprising converging lens means having an internal face with planar portions butted against the planar outer faces of the first and second transducer means, respectively, said lens means being formed of synthetic rubber material through which the speed of ultrasound waves is substantially slower than the speed of ultrasound waves through soft tissue and having a convexly curved outer face for engagement with the skin covering the internal body matter toward which the ultrasound waves are transmitted, said convexly curved outer face including two portions one of which is larger and more gradually curved than the other portion and each of said portions being centered over the space between the first and second transducer means so that both portions extend partly over both transducer means, whereby the major portion of the ultrasound waves transmitted by the first transducer means pass through the larger, more gradually curved portion of the outer face of the lens means and are focused at a location spaced from the first transducer means and the smaller portion of the ultrasound waves transmitted by the first transducer means pass through the smaller, more sharply curved convex portion of the outer face of the transducer means and are focused at a distance from the first transducer means closer than the focusing of the ultrasound waves passing through the larger portion.