JPS6287141A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ultrasonic diagnostic device that excites an ultrasonic transducer with a burst wave from a pulser circuit. The present invention relates to an ultrasonic diagnostic apparatus in which a DC voltage is applied to determine the wave height of a burst wave through a circuit consisting of the following.

(Prior Art) An example of an ultrasonic diagnostic apparatus equipped with a conventional PAL+1 circuit is shown in FIG. 4. In Figure 4, super sound 2! l! The diagnostic device includes a trigger circuit 1 that outputs a set number (usually 3 to 4) of 1-trigger signals at predetermined intervals (based on an external timing signal), and a trigger circuit 1 that is activated by the trigger signal. Output voltage of DC voltage source 2 or 3 +
The pulser circuit 5 outputs a burst wave having a wave height determined by (1) or -(2) to the ultrasonic indicator 4.

In the above configuration, when the timing signal shown in FIG. 5 (a) is applied to the trigger circuit 1, the l-trigger circuit 1
Output the trigger signal shown in Figure (b). The number of trigger signals corresponds to the number of bursts set in the trigger circuit 1. The pulse 1 circuit 5 is driven by this trigger signal,
A burst wave (an ultrasonic sensor excitation signal with a wave height of +V or -■) shown in FIG. 5(c) is output. As a result, ultrasonic waves of a predetermined intensity are projected toward the subject G-1.

(Problem that R, Akira is trying to solve) However, in conventional ultrasonic IfFi devices, the pulser circuit outputs burst waves whose wave height is always constant (+V or -■) according to the number of trigger signals. Therefore, if the pulser circuit is constantly driven due to a problem with the trigger circuit, etc. (a condition in which more than a predetermined number of trigger signals are continuously applied), the heat generated by the ultrasonic transducer increases, and the ultrasonic transducer There was a risk of damaging the equipment or causing burns to the subject. Therefore, problems with the trigger circuit and the like not only cause serious damage to the equipment but also pose a problem of lack of safety.

The present invention has been made in view of the above, and an object thereof is to provide an ultrasonic diagnostic apparatus that prevents equipment damage caused by troubles such as a trigger circuit, and improves safety.

(Means for Solving the Problems) The ultrasonic diagnostic apparatus of the present invention that achieves the above object has a configuration in which a DC voltage for determining the wave height of a burst wave is applied to a pulser circuit through a circuit consisting of a resistor and a capacitor. It has become.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. 1st
In the figure, the same reference numerals as in FIG. 4 have the same meanings, so the explanation here will be omitted. The feature of this embodiment is that the output +V of the DC voltage source 2 is applied to the pulser circuit 5 through a circuit 6 consisting of a resistor R1 and a capacitor C1, and the output +V of the DC voltage source 2 is applied to the pulser circuit 5 through a circuit 7 consisting of a resistor R2 and a capacitor C2. It is at the point where the output of 3 -■ is applied.

In addition, each resistance value of circuits 6 and 7 and lff of each capacitor
The 1 values are equal: R (this value is chosen relatively large) and C, respectively.

In the above configuration, in a normal burst state (a state in which 3 to 4 trigger signals are given in a short time), the circuit in Figure 1 equivalently becomes the configuration in Figure 2 (A) (here (The paper resistance value R of each resistor R and R2 is large, so it is omitted.) That is, the ultrasonic sensor 4 (shown as a capacitor with a capacitance CD) has a switch 8 (pulsar circuit 5 ). In the initial state of the circuit shown in FIG. 2(A), the voltage E between a and b is 2■ (the charge stored between a and b is VC). In this state, if the switch 8 is switched from a-+b1 or from b to a, the charge will decrease by 2VC1 (correctly 2ECI) each time the switch 8 is switched. Therefore, the a-be voltage E is expressed by the following relational expression, and the output of the pulser circuit 5 has a waveform at time T1 in FIG. 3(b).

E = 2V E = 2V (C-2C)/(C+C,) (1) p E = 2V ((C-2C)/(C+C)) 0(n)
p pHowever, E...Voltage between a and b in initial state E(1)...
Voltage E between a and b after switching once... Voltage between a and b after switching n times (n) As is clear from the above formulas and FIG. 3 (a), the output of the pulsar circuit 5 attenuates with a time constant determined by the ratio of C (capacitance of capacitors C1 and C2) and C, (capacitance of ultrasonic transducer 4). This decrease in the output of the pulser circuit 5 is
The normally used number of bursts (3 to 4) hardly poses a problem in practice.

On the other hand, when the burst state continues for a long time, the equivalent circuit in FIG. 1 changes from FIG. 2(a) to FIG. 2(b). In the configuration shown in FIG. 2(b), charge is supplied to the ultrasonic sensor C from a DC voltage [2 or 3 via a resistor R1 or R2. At this time, the amount of charge Q flowing into the ultrasound sensor CD
, becomes V-t/R (Q, = V-t/R, which indicates the time that the contact point of t·2 inch 8 is in contact with a or b, which is an extremely short time). Further, the charge fiQ consumed by the ultrasonic transducer C6 is E-C (Qo=E-C). Here, since Q.=Qo holds, the voltage between a and b is E
is the following relational expression.

E=V-t/R-CD Therefore, when the burst continues for a long time, the output of the pulser circuit 5 decreases with a time constant determined by R and C6, and eventually reaches the voltage V- determined by the resistance value R. Calm down to t/R・Cp.

This output voltage has a waveform shown at time T2 in FIG. 3(b). Thereby, when the burst continues for a long time, a large voltage +■ or -■ is not applied to the ultrasonic transducer Cp.

(Effects of the Invention) As explained above, according to the ultrasonic diagnostic apparatus of the present invention,
Since a DC voltage that determines the wave height of the burst wave is applied to the pulser circuit via a circuit consisting of a resistor and a capacitor, heat generation of the ultrasonic transducer can be suppressed even when the burst is long.

Therefore, a caused by troubles in the trigger circuit, etc.
This can prevent damage to the X and improve safety.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2(A) and (B) are both circuits of FIG. 1, and FIGS. Operation waveform diagram in one embodiment of 4th
5 is a configuration diagram showing a conventional example, and FIGS. 5(A) to 5(C) are operational waveform diagrams in the conventional example. 1...L-rigger circuit, 2 and 3...DC voltage source, 4
... Ultrasonic camera, 5... Pulsar circuit, 6 and 7.
...Circuit consisting of resistor and capacitor, 8...Switch (main part of pulsar circuit).

Claims (1)

[Claims] In an ultrasonic diagnostic apparatus equipped with a pulser circuit that outputs a burst wave to an ultrasonic transducer in accordance with a predetermined number of trigger signals applied at predetermined intervals, the pulser circuit is connected to the pulser circuit through a circuit consisting of a resistor and a capacitor. An ultrasonic diagnostic apparatus characterized in that a DC voltage is applied to determine the wave height of a burst wave.