JPS584539A - 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 The present invention relates to an ultrasonic diagnostic apparatus, and in particular to an improvement of a driving portion of a vibrator that emits ultrasonic waves.

Ultrasonic diagnostic equipment emits ultrasonic waves into the patient's body and receives the reflected waves to represent the distribution of reflectance to the sound waves inside the body as a picture image.
To obtain this, it is necessary to emit impulse ultrasound. PZT or the like is commonly used as an ultrasonic transducer, but when this is used in a normal configuration, the Q is high because there is no impurity, and the drive impulse energy is low even in the case of simultaneous excitation. Even when it is gone, a trailing sound wave remains due to the resonance vibration phenomenon. Conventionally, in order to eliminate this trailing phenomenon, a backing layer that absorbs the reflected wave force is provided on the back surface of the vibrator, and the damping characteristics of this backing layer prevent the trailing phenomenon. However, if this is done, the Q will be reduced by that amount, and the sensitivity at the time of reception will be reduced.

Conventionally, the backing layer has been designed to take these into consideration and find a compromise between 1lIl and 1lIl. Of course, it is ideal if the tailing phenomenon of the transmitted ultrasonic waves can be prevented without absorption by the backing layer, which would result in a high Q and a high receiving sensitivity.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved ultrasonic IL diagnostic device that can efficiently emit impulse ultrasonic waves with a simple configuration without providing a backing layer.

An embodiment of the present invention will be described below with reference to the drawings. As shown in Figure 1, the transmitter terminal 4 is
When you input the Luz signal, the king/? The transistor 11, which is a pulse drive switch, is driven, and the ultrasonic transducer 1B connected to the output terminal 8.4 is driven. Further, the transmitted pulse signal is delayed by the delay circuit 14 and sent to the transistor 120, which is an erase/pass switch, and when this transistor 12 operates, the ultrasonic transducer 13 is driven. The impedance element 21 is a resistor, and the impedance elements 22 and 28 basically constitute a voltage dividing circuit using resistors. Impedance element 24
゜25#'' is generally used as a capacitor.The impedance element 26 connects this drive circuit and the ultrasonic transducer 18.
It forms a matching circuit with the Impedance element 2
7.28 is for waveform shaping.

Next, the operation will be explained with reference to FIG. First, when a transmission pulse signal is input to the input terminals 1 and 2, the transistor 11 is activated, and the ultrasonic vibrator 18 is excited by the main impulse as shown in the figure j1!2.
A sound wave with a long tail is generated as shown in Figure 2. However, the input transmitting pulse signal is delayed by the delay circuit 14 having a delivery time DL of only i periods of the resonance frequency of the ultrasonic transducer 18, and the transistor 12 is activated after a time DL after the timing of the main pulse. Then, an erasing pulse as shown in FIG. 2C is applied to the ultrasonic transducer 18.

In this way, after the impulse excitation by the main pulse of the ultrasonic transducer 18#'i, the in-4 pulse with the same polarity after the machine period of the resonance frequency.
Lus is excited. Due to the in-wave excitation caused by this erasure/4', the ultrasonic transducer 18 emits a sound wave that resembles a tree in the oak tree in Figure 2, which has a sexual cycle difference and the same polarity as the sound wave shown in Figure 2 above.・Therefore, the peaks after the second IM of the sound wave due to the main/# Lus (Fig. 2 b) are canceled and attenuated by the sound wave K due to the cancellation noise (Fig. 2 d), and in the end they actually become the Fi second peak. In-74 ultrasonic waves as shown in the figure are emitted. As described above in the embodiments, according to the present invention, in-74 ultrasonic waves can be emitted from an ultrasonic transducer. 11 functions such as distance resolution can be improved. In addition, since there is no need to use a backing layer, the decrease in reception sensitivity due to the decrease in Q in the backing layer is improved, and the processing of the received signal is made easier. You can get an excellent interview.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an embodiment of the present invention, and Figure 2 is! FIG. 2 is a waveform diagram for explaining the operation of FIG. 1; DESCRIPTION OF SYMBOLS 11... Main pulse drive switch, 12... Erasing/input drive switch, 18... Ultrasonic transducer, 14... Delay circuit. Applicant: Shimadzu Corporation Jun 1, Book 2, So

Claims (1)

[Claims] (1) Give the main nollus to the ultrasonic transducer to in/4
At the same time, the ultrasonic transducer is impulsed to the same polarity by applying a cancellation pulse at a timing delayed from the timing of the raw 4' pulse by approximately a strong period of the resonant frequency of the ultrasonic transducer. An ultrasonic diagnostic apparatus characterized in that the ultrasonic transducer is excited to emit an ultrasonic sound #jLt.