JPH0568980B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a phased array ultrasonic diagnostic device, and more specifically, it improves a method for controlling the aperture in the thickness direction of a transducer that is divided in the thickness direction of an array type transducer. The present invention relates to an ultrasonic diagnostic device.

(Prior art) The sound field scanning method used in phased array ultrasound diagnostic equipment controls the phase or delay time of a high-frequency electrical signal applied to an ultrasound probe having a large number of piezoelectric transducers. Scanning is performed by changing the direction of ultrasound transmitted from a sonic probe.
The signal that is received and converted into an electrical signal is restored by performing the opposite processing to that used in the case of transmission. An example of a conventional wave transmitting/receiving circuit of this ultrasonic diagnostic apparatus is shown in FIG. In the figure, 1 is a probe consisting of many transducers that convert electrical signals into ultrasonic signals and transmit them, and receive reflected waves and convert them into electrical signals. It is composed of vibrator rows 2A, 2B and a central vibrator row 3 in the middle, and has a structure having a plurality of vibrators in the arrangement direction. The transducer rows 2A and 2B are connected to the same transmitting/receiving circuit consisting of a transmitting circuit 4A and a receiving circuit 4B, and the central transducer row 3 is connected to a transmitting/receiving circuit consisting of a transmitting circuit 5A and a receiving circuit 5B. has been done. In this way, the transducer rows 2A and 2B at both ends in the thickness direction and the central transducer row 3 are controlled separately, and the operation mode determines whether only the central transducer row 3 is operated or all the transducer rows are operated. By selecting , it is possible to distinguish between focusing on short distances and focusing on long distances.

(Problem to be Solved by the Invention) By the way, in the conventional device shown in FIG. 3, two systems of wave transmitting and receiving circuits are used to control the aperture in the thickness direction, so the scale of the entire wave transmitting and receiving circuit becomes extremely large. ,
Therefore, the number of signal lines associated therewith has increased in proportion to the number of wave transmitting/receiving circuits. If the device is further divided into multiple stages in the thickness direction, more wave transmitting/receiving circuits and signal lines will be required, resulting in a larger scale, which inevitably increases the size and cost of the device.

The present invention has been made in view of the above points, and its purpose is to control the aperture in the thickness direction with a simple circuit, and to reduce the number of necessary transmitting/receiving circuits, signal lines, etc. The objective is to realize a sonic diagnostic device.

(Means for Solving the Problems) A typical example of the present invention for solving the above-mentioned problems is a phased array ultrasonic diagnostic apparatus in which a plurality of transducers are arranged in the thickness direction to form one channel. The transmitting circuit and receiving circuit are
The plurality of transducers are commonly used, and some of the plurality of diagnostic elements are connected to the wave transmitting circuit and the wave receiving circuit via a thickness direction aperture control circuit. Further, the other ones of the plurality of vibrators are connected to the wave transmitting circuit and the wave receiving circuit without going through the thickness direction aperture control circuit, and the thickness direction aperture control circuit controls A variable resistance means whose internal resistance value can be controlled by a signal, and a voltage connected in parallel with the variable resistance means, which has a low impedance for the transmitted signal and a high impedance for the received signal. It is characterized in that it is composed of nonlinear impedance means having dependence.

(Function) The transmission signal from the transmission circuit excites all the transducers arranged in the thickness direction to transmit ultrasonic waves, and among the reflected waves from the reflector, the vibration in which the aperture control means is inserted is transmitted. The input of the received signal received by the child to the receiving circuit is controlled by the control signal of the aperture control means, and the aperture control in the thickness direction is performed at the time of wave reception by the input of the control signal.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of an embodiment of the present invention. In the figure, parts equivalent to those in FIG. 3 are given the same reference numerals. The probe 1 shown in FIG. 1 has three rows of transducers in the thickness direction, and only one channel of a large number of transducers, which differ depending on the application, is shown in the horizontal direction. 11A and 11B are vibrators provided outside in the thickness direction, and both are connected in parallel. 1
Reference numeral 2 denotes a vibrator provided at the center in the thickness direction, and is connected to a connection point between the wave transmitting circuit 4A and the wave receiving circuit 4B.
13 is a high-voltage passing diode circuit in which diodes that operate at high voltage are connected in antiparallel to allow a high-voltage signal, which is a transmitting signal, to pass through, but not to pass a weak receiving signal; This is a FET that controls the passage of weak received signals by changing the internal impedance, and is connected in parallel to the high voltage passage diode circuit 13.
B and the connection point between the wave transmitting circuit 4A and the wave receiving circuit 4B. 15 is a fixed resistor for discharging the charges accumulated in each vibrator.

Next, the operation of the embodiment configured as described above will be explained. The transmitted signal that has been amplified and otherwise processed by the transmitting circuit 4A passes through the high voltage passing diode circuit 13 to excite the vibrators 11A and 11B, and also directly excites the vibrator 12 to generate three vibrations in the thickness direction. Ultrasonic waves are transmitted from the child at the same time. Among the reflected signals reflected from the target object and returned to the transducers 11A, 11B, and 12, the signal received by the transducer 12 enters the receiving circuit 4B as it is, and is transmitted to the transducers 11A, 11B.
The received signal is input to FET14. Since the received signal is weak, high voltage passing diode circuit 1 is used.
It is not possible to pass 3. The internal resistance between the drain and the source of the FET 14 changes depending on the control signal input to the gate, and the FET 14 turns on and off in response to the received signal.
Performs off control. When FET14 is on, the received signal passes through and is input to the receiving circuit 4B, and the FET14 is turned on.
14 is off, the received signal does not pass through, and only the received signal from the central vibrator 12 among the three vibrators is input to the wave receiving circuit 4B. Therefore, by controlling the FET 14 with a control signal, the aperture value of the probe 1 in the thickness direction can be effectively controlled.

Note that the present invention is not limited to the above embodiments. FIG. 2 is a diagram showing a circuit according to another embodiment of the present invention, FIG. 2 is a circuit diagram thereof, and FIG. In the figure,
Components equivalent to those in FIG. 1 are given the same reference numerals. In the figure, 16A and 16B are transducers provided outside the transducers 11A and 11B in the thickness direction of the probe 1, and 17A is an aperture control circuit directly connected to the parallel circuit of the transducers 11A and 11B. 17B is an aperture control circuit connected in series to the parallel circuit of vibrators 16A and 16B. Aperture control circuit 17A, 17B
As shown in the aperture control circuit 17 in Fig. 1, it is composed of a parallel circuit of a high voltage passing diode circuit 13 and an FET 14, and a fixed resistor 8 is inserted between this circuit and the ground. The circuit in this example is for probe 1.
is divided into multiple stages in the thickness direction, and the transducers 11A and 11B on both sides of the central transducer 12 are connected to the aperture control circuit 17A.
, the transducers 16A and 16B are connected to the aperture control circuit 17B.
It is connected to. Aperture control circuit 17A, 1
By controlling each of 7B, the aperture value of the probe 1 can be changed. As is clear from FIG. 2, the number of aperture control circuits may be increased each time the number of divisions in the thickness direction increases. The high voltage passing diode circuit 13 of the aperture control circuit 17 may be any circuit as long as it has low impedance against high voltage.
Further, the FET 14 may be any other circuit as long as it is a variable resistance circuit controlled by a control signal.

As explained above, according to this embodiment, aperture control in the thickness direction can be performed by using only one transmitter/receiver circuit for one channel in the array direction, and the This can be realized with the same configuration as the transmitter/receiver circuit.

Vibrators in the same thickness direction in all channels in the arrangement direction can be controlled with the same control signal.
Transmission/reception signals and aperture control signals can be realized with fewer configurations than in the past.

(Effects of the Invention) As explained in detail above, according to the present invention, paths are automatically established between transmitting and receiving waves by using the parallel circuit of linear elements and nonlinear elements and the level difference between transmitting and receiving waves. By switching the thickness direction, it is possible to easily control the opening in the thickness direction. That is, the number of wave transmitting/receiving circuits and the number of signal lines associated therewith can be reduced, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is a circuit diagram of another embodiment of the present invention, and FIG. 3 is a diagram of a conventional wave transmitting/receiving circuit. 1... Probe, 4A, 5A... Transmission circuit, 4
B, 5B... Receiving circuit, 11A, 11B, 12,
16A, 16B... vibrator, 13... diode circuit for high voltage passage, 14... FET, 15... fixed resistor, 17, 17A, 17B... aperture control circuit.

Claims (1)

[Scope of Claims] 1. In a phased array ultrasonic diagnostic apparatus in which a plurality of transducers are arranged in the thickness direction to form one channel, a wave transmitting circuit and a wave receiving circuit are commonly used for the plurality of transducers. Some of the plurality of vibrators are connected to the wave transmitting circuit and the wave receiving circuit via a thickness direction aperture control circuit, and some of the plurality of vibrators are connected to the wave transmitting circuit and the wave receiving circuit via a thickness direction aperture control circuit. Others are connected to the wave transmitting circuit and the wave receiving circuit without going through the thickness direction aperture control circuit, and the thickness direction aperture control circuit can control an internal resistance value by a control signal. variable resistance means, and a voltage-dependent nonlinear impedance means that is connected in parallel with the variable resistance means and has a low impedance for the transmitted signal and a high impedance for the received signal. A phased array ultrasonic diagnostic device comprising: 2. The phased array ultrasonic diagnostic apparatus according to claim 1, wherein the resistance value of the variable resistance means is controlled by the same control signal for all channels in a direction perpendicular to the thickness direction.