ULTRASONIC DIAGNOSTIC DEVICE

摘要

PROBLEM TO BE SOLVED: To improve a resolution by narrowing the transmission ultrasonic beams of an ultrasonic diagnostic device from a short distance to a long distance. SOLUTION: In a driving circuit 2, pulses CD-3 whose amplitude becomes small and frequency becomes low with time are generated and a vibrator at the opening center part of an ultrasonic converter is driven. In the driving circuit 3, the pulses CD-M3 whose amplitude is fixed and frequency becomes low with time are generated and the vibrator at the opening side edge part of the ultrasonic converter is driven. An effective opening corresponding to high frequency components is made narrower than the effective opening corresponding to low frequency components and ultrasonic waves are transmitted from the converter 1 to a testee body. Signals received in the converter are delayed and synthesized, a band-pass filtering processing is performed and they are displayed as tomographic images. Narrow transmission beams are realized from the short distance to the long distance and the resolution of this ultrasonic diagnostic device is improved.