| 摘要 |
PURPOSE:To provide focal adjustability easily even in the lens direction by dividing an ultrasonic vibrator to the longitudinal and width directions of a probe, and selectively controlling those of the echo signals from a body to be inspected which operate a vibrator divided across the width on the basis of a voltage signal in compliance with the focal distance. CONSTITUTION:A pulser 3 oscillates high frequency pulses when a signal transmit pulse is given, and an ultrasonic probe 1 emits an ultrasonic beam to a body to be inspected, and the echo signal generated near the surface of the body to be inspected is taken in, and with elapse of the time, echo signals from deeper positions in the body are taken in bit by bit. The voltage Vc rises at a certain slope by reference to the voltage VE, and when echo signal generated at small distance is taken in, diodes D1, D2, D3 are put off, and only a vibrator 2c is connected with the pulser 3. Now emission of ultrasonic beam due to vibrator 2c solely takes place, and the focal distance of the ultrasonic beam becomes small. In the same manner, when echo signals generated at a middle distance and a large distance are to be taken in, the focal distances become middle and large, respectively. This allows maintaining a favorable focal distance at all times, to lead to enhancement of the resolution. |
