Received ultrasonic phase matching circuit

Details Received ultrasonic phase matching circuit Received ultrasonic phase matching circuit

1990-07-30

1991-07-16

Jaworski, Francis

Surgery

Truss

Pad

324 77H, A61B 800

Patent

active

050316257

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a received ultrasonic phase matching circuit to be used in an ultrasonic diagnostic apparatus and more specifically to a received ultrasonic wave phase matching circuit which continuously changes, during the receiving period, the ultrasonic wave echo receiving focus and aperture.


PRIOR ART

In an ultrasonic diagnostic apparatus, the ultrasonic wave echo receiving focus and aperture are continuously changed to make a resolution of B-mode image high and uniform at the range from the shallow region of object to the deep region thereof depending on the depth of echo generating point while the echo of one sound line is received. This is to obtain uniform and high resolution by making constant a ratio of focal distance and aperture, namely the F number during reception of echo. A prior art of the circuit to realize such function is shown in FIG. 3. In the circuit of FIG. 3, the receiving signals of individual transducer elements of the ultrasonic wave transducer array not illustrated are supplied to a plurality of channels 1.sub.1 -1.sub.9 forming the maximum aperture to receive the ultrasonic wave echo of the one sound line and the receiving signal of each channel is respectively attenuated by a plurality of variable attenuators 2.sub.1 -2.sub.9 forming a variable aperture means 2, delayed by a plurality of variable delay lines 3.sub.1 -3.sub.9 forming a variable focus means 3 and is then input to a plurality of input lines of a matrix switch circuit 4. The matrix switch circuit 4 comprises therein a plurality of input lines extending in horizontal and a plurality of output lines extending in vertical, has switches arranged at the intersecting points of these input lines and output lines and is designed to connect the desired input lines to the desired output lines by controlling ON and OFF conditions of respective switches. A plurality of output lines of matrix switch circuit 4 are respectively connected with the taps of a fixed delay line 5 having a plurality of taps. The receiving signals of a plurality of channels can be input to the desired taps of fixed delay line 5 by controlling ON and OFF conditions of the switches of the matrix switch circuit 4. From the output ends of delay line 5, the signals input to respective taps are output with addition of the delay time corresponding to the tap position. Combination of the matrix switch circuit 4 and fixed delay line with taps 5 forms a beam steering means which determines direction of received ultrasonic beam. The variable attenuators 2.sub.1 -2.sub.9 of the variable aperture means 2, variable delay lines 3.sub.1 -3.sub.9 of the variable focus means 3 and each switch of matrix switch circuit 4 are respectively controlled by the aperture control signal, focus control signal and steering control signal sent from the control circuit not illustrated to determine the aperture, focus and azimuth angle for reception of ultrasonic echoes.
For the reception of ultrasonic wave echo of the one sound line, the aperture means 2 operates to gradually expand the small aperture around the center channel 1.sub.5 at the beginning of reception to a larger aperture with the aperture control signal, while the variable focus means 3 operates to gradually control the shortest focal distance at the beginning of the reception, namely the longest delay time of the variable delay lines 3.sub.1 -3.sub. 9 to the longer focal distance, namely the shortest delay time of the variable delay lines 3.sub.1 -3.sub.9 with the focus control signal. The matrix switch circuit 4 realizes beam steering in accordance with the direction of sound line of ultrasonic wave echo with the steering control signal. The received ultrasonic wave phase matching circuit of the present invention will be used for any types of ultrasonic diagnostic apparatus of the linear scanning type, sector scanning type and convex scanning type. Namely, in the linear scanning type and convex scanning type ultrasonic diagnostic appartuses, the scanning of ultrasonic beam is reali

REFERENCES:
patent: 4542657 (1985-09-01), Barber et al.
patent: 4649392 (1987-03-01), Apostolos
patent: 4888746 (1989-12-01), Wurster et al.
patent: 4949312 (1990-08-01), Iwasawa
patent: 4951219 (1990-08-01), Zimmer

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