JPH01262845A - Ultrasonic diagnosing device - Google Patents

Abstract

PURPOSE:To improve a receiving S/N ratio by providing an impedance converting means, which takes-in a receiving signal from an ultrasonic oscillating element with a high impedance and outputs the taken-in receiving signal with a low impedance, in each ultrasonic oscillating element. CONSTITUTION:The reflected wave of an ultrasonic wave, which is sent from ultrasonic oscillating elements 1a-1c, is received again by the said oscillating element 1a-1c and the receiving signal by this ultrasonic reception wave is taken in impedance converting means 5a-5c. During a period, in which a driving pulse is not impressed to the ultrasonic oscillating elements 1a-1c, a transistor is operated as an emitter follower. For the feature of the emitter follower, an input impedance is high and an output impedance is low. Thus, since the receiving signal is transmitted with the low impedance by the effect of the impedance conversion, a bad influence due to the distributing capacity of a cable 6 is hardly received. Then, since signal damage is extremely small, the receiving S/N ratio is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is capable of diagnosing a subject by processing received signals based on reflected waves of ultrasonic waves transmitted toward the subject. The present invention relates to an ultrasonic diagnostic device.

(Prior Art) Conventionally, in an ultrasonic diagnostic apparatus, a plurality of adjacent ultrasonic vibrating elements 1a to 1C among the ultrasonic vibrating elements that transmit and receive ultrasonic waves are commonly connected as shown in FIG. In some cases, an ultrasound probe configured as channel 1 is used. This ultrasonic probe generates a transmission signal (also called a drive pulse or an excitation pulse) that is applied to these ultrasonic transducer elements 1a to 1C, and also generates a reception signal (reception echo) from the ultrasonic transducer elements. )
A device main body 3 equipped with a transmitting/receiving circuit 4 for processing is connected by a cable (conductive wire) 6. Further, an impedance conversion circuit 2 is provided for each channel to perform impedance conversion and improve the reception S/N ratio.

(Problem to be Solved by the Invention) By the way, in order to increase the S/N ratio of the transmitted and received signals in the array transducer as described above, the element pitch of the transducer is increased to increase the ultrasonic transducer per channel. When trying to increase the area of the ultrasonic transducer, in order to suppress unnecessary vibrations in directions other than the thickness direction of the ultrasonic transducer, it is usually necessary to set w/l≦1 (W:
It is necessary to divide each ultrasonic vibrating element into sub-dies or straws so as to satisfy the width in the arrangement direction of the vibrating element, t; the thickness of the vibrating element.

When the impedance value of the ultrasonic transducer element corresponding to the channel is small, the effect of impedance conversion such as the emitter follower 2 provided for the purpose of improving reception sensitivity may be reduced.

For example, in the case of an array vibrating element, there is a method of increasing the area of the ultrasonic vibrating element per channel in order to increase the SZN ratio of transmitted and received signals, but in such a case, the impedance value per channel becomes small, The effect of impedance conversion is also reduced.

Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus that improves the reception S/N ratio.

[Structure of the Invention] (Means for Solving the Problems) The structure of the present invention for achieving the above object includes an ultrasonic probe in which a plurality of adjacent ultrasonic vibration elements are commonly connected to form a channel. However, in an ultrasonic diagnostic device that performs diagnosis based on the reflected waves of ultrasonic waves transmitted from this ultrasonic probe toward the subject, the received signal from the ultrasonic vibrating element is captured at high impedance, and the input/V Impedance conversion means for outputting the received signal at low impedance is provided for each ultrasonic transducer element.

(Function) The function of the present invention having the above configuration is that impedance conversion means is provided for each ultrasonic vibration element constituting each channel to reduce the output impedance of the vibration element.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1 is a circuit diagram showing the main parts of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, in which 1 is one channel among a plurality of channels in an ultrasonic probe, and 1a to 1C are each channel 1. Constituent adjacent ultrasonic vibration elements, 5
The impedance conversion means 5.8 connected to each of the ultrasonic vibrating elements 1a to 1C is a transmitting signal that allows the transmitting signal (drive pulse) used to excite the ultrasonic vibrating cables 1a to 1G to pass through with low layer loss. 7 is a pass circuit, 7 is a caulking circuit mainly composed of an operational amplifier 9, 6 is a cable, 4 is a transmitting/receiving circuit, and 3 is a device body incorporating the transmitting/receiving circuit.

Furthermore, the above ultrasonic probe consists of multiple channels.
The ultrasonic transducer elements constituting each channel are arranged in an array, but only one of the latter channels is shown in FIG.

The impedance conversion means 5a to 5C are provided corresponding to each ultrasonic transducer element constituting each channel, and capture and capture each received signal from the ultrasonic transducer elements 1a to 1C at high impedance. It has a function of outputting a received signal with low impedance.

Although various circuit configurations may be used to realize such a function, in this embodiment, an emitter follower using an L transistor (bipolar) is used. In other words, the received signals @ (received echoes) from the ultrasonic transducer elements 1a to 1G are transmitted to the base of the transistor, and the emitter output of the transistor is transmitted via the adder circuit 7, cable 6, etc. The signal is then transmitted to a transmitting/receiving circuit 4 in the main body 3 of the device.

The adder circuit 7 includes resistors R1 to R3 connected to the rear stage of each of the impedance conversion means 5a to 5C, and an operational amplifier 9 connected to the rear stage of each of the resistors R1 to R3.
, a negative feedback resistor Rf, and a diode 10.

The device main body 3 is a signal processing circuit that generates a transmission signal and processes the received signal taken in by the transmission/reception circuit 4 for taking in the received signal.

It is configured with a display device and the like that display the processing results. Since the configuration of this device main body is the same as the conventional one, detailed explanation thereof will be omitted.

The operation of the embodiment device having the above configuration will be explained.

Transmission> A drive pulse outputted from the transmitting/receiving circuit 4 in the device main body 3, specifically the balsa, passes through the cable 6° transmission signal passing circuit 8 and is applied to the vibrators 1a to 1C. As a result, ultrasonic waves are transmitted from the transducers 1a to 1C.

In the above transmission operation, the drive pulse is applied to the ultrasonic transducer elements 1a7'J to 10 via the transmission signal passing circuit 8, so the loss of the drive pulse (transmission signal) is extremely small.

<Reception> The reflected waves of the ultrasonic waves transmitted from the ultrasonic transducer elements 1a to 1C are received again by the transducer elements 1a to 1C, and the received signals (received echoes) resulting from this ultrasonic wave reception undergo impedance conversion. It is taken into the means 5a to 5C. During a period in which no drive pulse is applied to the ultrasonic transducer elements 1a to 1C, the transistor operates as an emitter follower, and the emitter current changes according to the received received signal. Emitter followers (collector grounded) are characterized by high input impedance (several tens of ohms or more) and low output impedance (several to several tens of ohms). After the emitter currents of each emitter follower are added by an operational amplifier 9, a change in the current value is converted into a change in voltage and transmitted to the device main body 3 via a cable 6. The received signal transmitted at low impedance is taken into the transmitting/receiving circuit 4 in the main body 3 of the device, and is subjected to signal processing in the signal processing circuit. Signal processing may involve forming an ultrasonic image of the subject, but may also include arithmetic processing for identifying tissue of the subject.

In the above receiving operation, the received signal is transmitted at low impedance due to the effect of impedance conversion, so it is unlikely to be adversely affected by the distributed capacitance of the cable 6, etc., and the signal loss is extremely low, improving the receiving S/N ratio. .

It is preferable that the impedance conversion means 5 as described above be provided within the ultrasound probe. In this case, in order to miniaturize the ultrasonic probe, it is preferable to form the means 5 into an IC (integrated circuit).

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made.

[Effects of the Invention] According to the present invention as detailed above, it is possible to provide an ultrasonic diagnostic apparatus with improved reception S/N ratio.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a circuit diagram of the main parts of an iIA ultrasound diagnostic device which is an embodiment of the present invention, and Fig. 2 is a circuit diagram of the main parts of a conventional ultrasound diagnostic equipment. be. ] a to 1C... vibrator, 5... impedance conversion means.

Claims (1)

[Claims] An ultrasonic probe that has an ultrasonic probe with a plurality of adjacent ultrasonic transducer elements commonly connected to form a channel, and that performs diagnosis based on the reflected waves of the ultrasonic waves transmitted from this ultrasonic probe toward the subject. An ultrasound diagnostic apparatus, characterized in that each ultrasonic transducer element is provided with impedance conversion means for capturing a received signal from the ultrasonic transducer element at high impedance and outputting the captured received signal at low impedance. Diagnostic equipment.