JPH09238939A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower noise components attributed to a cross talk contained in a received signal by restraining the generation of a capacitive cross talk significantly. SOLUTION: A plurality of vibrators 2a1 -2an of an array type vibrator 2 are divided into the vibrators 2a1 -2am exclusively for transmission only for the processing of transmitting a continuous wave and the vibrators 2am+1 -2an exclusively for reception only for the processing of receiving a continuous wave. Two vibrators at a part where the vibrators 2a1 -2am and the vibrators 2am+1 -2an are adjacent to each other are set on a transmission side stop vibrator 2am by which the transmission of the continuous wave is stopped and on a reception side top vibrator 2am+1 by which the reception of the continuous wave is stopped. As cross talk reducing circuit to reduce cross talks mixed into a received continuous wave signal, setting circuits 10a, 10b, 11a, 11b and 12 are connected to signal lines of the transmission side stop vibrator 2am and the reception side stop vibrator 2am+1 to set the transmission side stop vibrator 2am and the reception side stop vibrator 2am+1 to a GND potential.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus using continuous wave (CW) for transmitting and receiving ultrasonic waves, and in particular,
The present invention relates to an ultrasonic diagnostic apparatus that reduces crosstalk between adjacent transducers and wiring and improves transmission / reception sensitivity.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus transmits an ultrasonic signal into a subject and obtains biological information from reflected signals from each tissue in the subject, and is a highly safe non-invasive examination apparatus. Is often used as

Among such ultrasonic diagnostic apparatuses, there is an ultrasonic diagnostic apparatus for obtaining blood flow velocity information as biometric information. The ultrasonic diagnostic apparatus for obtaining the blood flow velocity information is roughly classified into a continuous wave Doppler (CWD) type diagnostic apparatus and a pulse Doppler (PWD) type diagnostic apparatus,
A continuous wave Doppler type apparatus uses a continuous wave signal for transmission ultrasonic waves.

Here, FIG. 9 shows an ultrasonic wave transmission / reception unit in a continuous wave Doppler type ultrasonic diagnostic apparatus.

According to FIG. 9, a plurality of vibrators 100a ₁ ...
An array type vibrator 100 in which 100a _n are linearly arranged is
Transmitter-only (T) transducer 100a _1-
100a _m and reception-only (R) transducer 100a _{m + 1}
It is divided into 100a _n . And send only (T)
The oscillators 100a _{1 to} 100a _m are
Drive circuit 101a which are respectively connected to _{1 ~100a m}
Continuous wave sent from the _{1 ~101a m} (radio frequency) signal (C
Driven by W), an ultrasonic signal is transmitted toward the subject. The ultrasonic signal reflected in the living body on the basis of this transmitted ultrasonic signal is the reception-only (R) transducer 100a _{m + 1.}
˜100a _n , each transducer 100a _{m + 1} ˜10
Adder not shown after being amplified and impedance-converted by amplifiers 101a m + ₁ ~101a _n connected to 0a _n, then sent to a Doppler signal measuring unit. After various calculation processes are performed by the Doppler signal calculation unit, the blood flow velocity information is displayed on a monitor or the like.

By the way, in the ultrasonic wave transmitting / receiving section of the above-mentioned continuous wave Doppler type diagnostic apparatus, crosstalk between adjacent transmission / reception signals (capacitive crosstalk) is S / of received signals.
A transducer in a range (P) in which transmission / reception is stopped for a plurality of transducers (transmission-side transducer 100a _m and reception-side transducer 100a _{m + 1} ) adjacent to each other because the N ratio is affected. CW transmission / reception is stopped as
UTE, and the driving oscillator is represented by ACTIVE).

[0007]

However, in the configuration of the ultrasonic transmitting / receiving section described above, the capacitive impedance component Zc1 existing between the adjacent transducers which causes the capacitive crosstalk itself and the PWB (printed wiring). Since the capacitive impedance component Zc2 or the like floating between the wiring patterns of the board), between the probe cables, and between the other cable wiring is not reduced, for example, in the array direction of the transducers adjacent to the CW transmission dedicated transducer, Capacitive crosstalk occurs due to the propagating vibration, and is mixed into the reception-only oscillator and its signal line via the stop oscillator and its signal line. As a result, noise due to the mixing of crosstalk occurred in the reception signal received by the reception-only transducer, and the accuracy of the blood flow velocity information deteriorated.

Further, due to the impedance component Zc2 floating between the wiring patterns and between the cables described above, capacitive crosstalk occurs between the patterns, between the cables, and the like, and the capacitive crosstalk occurs between the wiring patterns and the cables. Crosstalk is mixed in the received signal. As a result, noise was generated in the reception signal received by the reception-only transducer as described above, and the accuracy of blood flow velocity information was also deteriorated.

On the other hand, in the structure of the conventional ultrasonic transmitter / receiver, providing a plurality of stop vibrators between the transmission-dedicated transducer and the reception-dedicated transducer means that the transmission-only transducer and the reception-only transducer that are actually driven are provided. Since it means that the number of oscillators is reduced and the transmission and reception sensitivity and the sound field are deteriorated, it has been desired to reduce the number of stopped oscillators as much as possible.

However, in the conventional configuration, since the generation of capacitive crosstalk itself is not suppressed, the number of stop transducers provided between the transmission-dedicated transducer and the reception-dedicated transducer is equal to the number of adjacent transmission / reception transducers. It should be a sufficient number so that crosstalk between signals has almost no effect on the received signal, which causes deterioration of the above-mentioned transmission / reception sensitivity and sound field characteristics (propagation characteristics of ultrasonic waves such as energy and directivity). I'm gone.

The present invention has been made in order to solve the above-mentioned problems, and floats between the capacitive impedance components existing between the adjacent vibrators or the cable wirings which cause the capacitive crosstalk itself. It is a first object of the present invention to significantly suppress the occurrence of capacitive crosstalk by reducing the capacitive impedance component and the like, and reduce the noise component due to the crosstalk included in the received signal. A second object is to improve the transmission / reception sensitivity and the ultrasonic wave propagation characteristics by reducing the number of stop transducers as compared with the conventional one, in other words, increasing the number of actual driving transducers as compared with the conventional one. To do.

[0012]

In order to solve the above problems, according to the ultrasonic diagnostic apparatus of claim 1,
An ultrasonic wave that receives a continuous wave signal reflected from the subject according to the continuous wave ultrasonic signal transmitted to the subject and obtains biological information of the subject based on the received continuous wave signal The diagnostic device has an array type oscillator in which a plurality of oscillators are arrayed, and the plurality of oscillators forming the array type oscillator include a transmission-only oscillator that performs only the transmission processing of the continuous wave signal and the continuous oscillator. It is divided into a receive-only oscillator that only performs wave reception processing, and at least one oscillator in the part where the transmit-only oscillator and the receive-only oscillator are adjacent stops the transmission and reception of the continuous wave signal. A crosstalk reduction circuit is provided which is set in the oscillator and is connected to the signal line of the stop oscillator and reduces crosstalk mixed in the received continuous wave signal.

Particularly, according to the ultrasonic diagnostic apparatus of the second aspect, the crosstalk reducing circuit is a setting circuit which is connected to the signal line of the stop oscillator and sets the stop oscillator to the GND potential. .

Further, in particular, according to the ultrasonic diagnostic apparatus of the third aspect, the crosstalk reducing circuit is a low impedance circuit which is connected to the signal line of the stop oscillator and reduces the impedance of the signal line. .

Further, according to the ultrasonic diagnostic apparatus of the fourth aspect, the impedance lowering circuit includes a low impedance bias source circuit for applying a low impedance bias voltage source of approximately 0 volt to the signal line. .

Further, according to the ultrasonic diagnostic apparatus of the fifth or sixth aspect, the stop transducer is one of the transmission-side stop transducer and the reception-only transducer set from among the transmission-only transducers. It has a receiving side stop oscillator set from
An amplifier such as a buffer amplifier for signal amplification is connected to the plurality of oscillators, and the crosstalk reduction circuit keeps the bias voltage of the amplifier connected to the transmission-side stop oscillator ON. Then, only the bias voltage of the amplifier connected to the receiving side stop oscillator is turned off.
It is provided with a voltage control circuit for F.

Further, according to the ultrasonic diagnostic apparatus of the present invention, the stop transducer has at least a transmission side stop transducer set from among the transmission-dedicated transducers, and the crosstalk reduction circuit. Has a shunt circuit that is connected to the signal line of the transmission-side stop oscillator and forcibly shunts the transmission-side stop oscillator to GND.

On the other hand, in order to solve the above-mentioned problems, according to the ultrasonic diagnostic apparatus of the eighth aspect, the ultrasonic signal of either the continuous wave or the pulse wave transmitted to the subject is used. In response to the continuous wave signal reflected from the subject, an ultrasonic diagnostic apparatus that obtains biological information of the subject based on the received continuous wave signal is an array type vibration in which a plurality of transducers are arranged. A plurality of transducers having a child and constituting the array-type transducer are a transmission-dedicated transducer that performs only the transmission processing of the continuous wave when transmitting and receiving the continuous wave signal, and a reception-only transducer that performs only the reception processing of the continuous wave. And at least one transducer in the portion where the transmission-only transducer and the reception-only transducer are adjacent to each other is set as a stop transducer for stopping transmission or reception of the continuous wave, and the pulse wave A circuit for removing the signal charge remaining in each of the plurality of vibrators at the time of reception is provided by being connected to each vibrator, and a signal line connecting the transmission-side stopped vibrator and the signal charge removal circuit is shunted to GND. It has a shunt circuit.

According to the ultrasonic diagnostic apparatus of the first aspect, the plurality of transducers forming the arrayed transducers perform only the transmission processing of the continuous wave signal and the transmission only transducer and the reception processing of the continuous wave. At least one oscillator (for example, one oscillator from the transmission-only oscillator (transmission-side stop oscillator)) that is divided into a reception-only oscillator and a transmission-only oscillator and a reception-only oscillator are adjacent to each other. One oscillator (reception-side stopped oscillator) from the dedicated oscillator is set as a stopped oscillator in which transmission and reception of continuous waves are stopped.

Particularly, according to the ultrasonic diagnostic apparatus of the present invention, the signal line of the stop oscillator is provided with a crosstalk reducing circuit for reducing crosstalk mixed in the received continuous wave signal. Since the setting circuit for setting the vibrator to the GND potential is connected, the transmission-dedicated vibrator and the reception-dedicated vibrator are separated in circuit. Therefore, the capacitive crosstalk that is mixed from the transmitting side to the receiving side due to, for example, the vibration of the adjacent vibrator is significantly reduced.

Further, in particular, according to the ultrasonic diagnostic apparatus of the first to third aspects, the impedance of the signal line of the stop oscillator is, for example, the impedance of the signal line as the crosstalk reducing circuit. Since a low-impedance circuit that reduces the bias voltage by applying a bias voltage of approximately 0 volt is connected, it is possible to significantly reduce the capacitive crosstalk between the signal lines generated through the signal lines.

Further, according to the ultrasonic diagnostic apparatus of claims 1 and 5 to 6, the voltage control circuit as the crosstalk reducing circuit is used for amplifying the received ultrasonic waves connected to each of the plurality of transducers. Since the bias voltage of the amplifier connected to the transmission-side stop oscillator in the amplifier (for example, buffer amplifier) is kept ON and only the bias voltage of the amplifier connected to the reception-side stop oscillator is turned OFF, Due to the characteristics of the buffer amplifier, the impedance of the output line of the buffer amplifier connected to the transmitting side stop oscillator can be reduced. Further, since the crosstalk signal sent to the amplifier via the stop oscillator on the receiving side is blocked by the output of the amplifier, the crosstalk signal is not included in the output of the amplifier.

Furthermore, according to the ultrasonic diagnostic apparatus of claims 1 and 7 to 8, the crosstalk reduction circuit is provided in the signal line of the transmission-side stop oscillator during transmission and reception of a continuous wave signal. As described above, since the shunt circuit for forcibly shunting the transmission-side stopped oscillator to GND is connected, the transmission-dedicated oscillator and the reception-dedicated oscillator are electrically separated. Therefore, the capacitive crosstalk that is mixed from the transmitting side to the receiving side due to, for example, the vibration of the adjacent vibrator is significantly reduced.

[0024]

Embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 shows the schematic arrangement of an ultrasonic diagnostic apparatus according to the first embodiment of the present invention. According to FIG. 1, the ultrasonic diagnostic apparatus transmits an ultrasonic signal to the inside of a subject and receives an ultrasonic signal (echo signal) reflected from the inside of an ultrasonic signal transmitting / receiving unit. 1 is provided.

The ultrasonic signal transmitting / receiving unit 1 described in the present embodiment shows a component for transmitting and receiving a continuous wave (CW). That is, the ultrasonic signal transmission / reception unit 1 includes an array type transducer 2 in which a plurality of transducers 2a _{1 to} 2a _n are linearly arranged.
have. This array-type vibrator 2 is provided with transmission-only (T) vibrators 2a _{1 to} 2a _m with a boundary in the approximate center in the array direction.
In addition, the transducers 2a _{m + 1 to} 2a _n dedicated to reception (R) are divided into two parts. Each drive circuit 3a ₁ to 3 A _m is connected to the transmission dedicated transducer 2a ₁ to 2A region _m, the transducer 2a by a continuous wave transmitted from the drive circuit 3a ₁ ~3a _m (radio frequency) signal (CW) _{1 ~2a m} is driven,
An ultrasonic signal is transmitted to the subject.

The reception dedicated transducer 2a _m + 1 ~2a each amplifier (buffer amplifier) 4a _m + 1 ~4a _n are connected to _n, it is received by the receive-only transducer 2a _m + 1 ~2a _n The echo signals are amplified (impedance conversion) via the amplifiers 4a _{m + 1 to} 4a _n .

On the other hand, the ultrasonic diagnostic apparatus comprises a received signal processing section 7, a B-mode tomographic image display section 8 and a Doppler signal calculation unit 9. The reception signal processing unit 6 includes each amplifier 4
a _{m + 1 to} 4a _n and connected to the amplifiers 4a.
_The signals output from _{m + 1 to} 4a _n are subjected to addition processing and the like to generate received signals.

One of the reception signals generated by the reception signal processing unit 6 is sent to the B-mode tomographic image display unit 7. B
The mode tomographic image display unit 7 detects the received signal and then scan-converts it via the frame memory to perform TV scanning B
A mode image signal is generated. The B-mode tomographic image display unit 7 displays the generated B-mode image signal as a B-mode tomographic image on a TV monitor or the like.

The other of the reception signals generated by the reception signal processing unit 6 is sent to the Doppler signal calculation unit 8.
The Doppler signal calculation unit 8 performs a phase detection process, a filter process, and the like on the received signal sent to generate a Doppler signal. Then frequency analyze this Doppler signal,
The result is displayed (superimposed on the tomographic image) as blood flow velocity information on the TV monitor of the B-mode tomographic image display unit 7, for example.

Further, in the ultrasonic signal transmission / reception unit 1 of the ultrasonic diagnostic apparatus of this embodiment, in order to prevent crosstalk between transmission and reception, the transducers for transmission 2a _m adjacent to each other with the center as a boundary along the arrangement direction. And the receiving-only vibrator 2a _{m + 1} are set as the vibrator in the transmission / reception stop range (P). The signal line connecting the transmission-side stop oscillator 2a _m and the drive circuit 3a _m is branched, and a switch (switching circuit) 10a is provided on the branched line. Similarly, on the receiving side, the signal line connecting the receiving-side stop oscillator 2a _{m + 1} and the amplifier 4a _{m + 1} is branched, and a switch 10b is provided on the branched line.

Stop oscillator 2 of switching devices 10a and 10b
The signal line opposite to the connection line of a _m and 2a _{m + 1} is GN
D (ground) is connected to each of the switching devices 10a, 10
b indicates opening / closing (ON) of the switching units 11a and 11b (switches).
/ OFF) is controlled by switching the stop oscillator 2a.
It is possible to connect _m and 2a _{m + 1} to GND. Also,
The switching timing of the switching units 11a and 11b of the switching devices 10a and 10b is controlled by the switching control unit 12 including a computer circuit or the like.

Note that the switching section 11a of the switch 10a and the switching section 11b of the switch 10b are each controlled to be open except when the ultrasonic signal is transmitted and received by the CW. A signal line connecting the transmission-side stop oscillator 2a _m and the drive circuit 3a _m is provided with a switcher (not shown) for controlling connection / disconnection of the oscillator 2a _m and the drive circuit 3a _m. The oscillator 2 is used when transmitting and receiving ultrasonic signals by CW.
The switching control is performed so that the a _m and the drive circuit 3 a _m are disconnected, and in other cases, the switching control is performed so that the vibrator 2 a _m and the drive circuit 3 a _m are connected.

Next, the overall operation of this embodiment will be described, focusing on the operation of the switching devices 10a and 10b.

In the ultrasonic diagnostic apparatus shown in FIG. 1, when performing various types of diagnosis using continuous wave (CW) such as CWD (continuous wave Doppler) type diagnosis (in CW transmission / reception mode). , The switching units 11a and 11b of the switchers 10a and 10b are respectively controlled to be closed according to the control from the switching control unit 12, and the stop transmission oscillator 2a _m and the stop reception oscillator 2a _{m + 1} are forcibly connected to the GND. To be done.

In this state, ultrasonic signals are transmitted and received by the vibrator outside the stop range. That is, the stop transducers 2a _m and the driving circuit 3 by switching device (not shown) on the line that connects the driving circuit 3a _m and stopping vibrator 2a _m
Since the the a _m are switching control to the non-connected state, the drive circuit 3a ₁ ~3a _m-1 from the transmission dedicated transducer 2a ₁ to 2A region
CW is sent to _m-1 and the transmission dedicated transducers 2a _{1 to} 2a
_{Although m-1} is driven (ACTIVE), CW is not sent from the drive circuit 3a _m to the stopped transmission oscillator 2a _m , and transmission is stopped (MUTE).

The signals output from the amplifiers 4a _{m + 2 to} 4a _n are received and processed by the reception signal processing unit 6 (ACTIVE), but the amplifiers 4a _m connected to the stopped reception oscillator 2a _{m + 1. The} signal output from ₊₁ is not subjected to reception processing by the reception signal processing unit 6 (MUTE).

At this time, since the potential of the stop oscillator between the transmitting side and the receiving side is set to the GND level, the transmitting side oscillator and the receiving side oscillator are separated in circuit. Therefore, for example, capacitive crosstalk that is generated due to vibration of adjacent transducers and that mixes from the transmission side to the reception side is significantly reduced, and as a result, the noise caused by the crosstalk included in the reception signal is significantly reduced. Can be made.

Further, in the past, since the number of stop oscillators between transmission and reception determines the degree of capacitive crosstalk mixed in the received signal, the number inevitably increases. Stop oscillator is forced to GN
Since the idea is to reduce the capacitive crosstalk itself to D, it is sufficient to provide a minimum required number of stop oscillators (for example, as shown in the present embodiment, 1
It is not necessary to increase the number of stop oscillators as compared with the conventional one. That is, the number of actual driving vibrators can be increased as compared with the conventional case, and the transmission / reception sensitivity and ultrasonic wave propagation characteristics are improved.

In this embodiment, an ON / OFF switch is provided in the connection line of the stop oscillator, and the stop oscillator is connected to the GND by opening / closing control (ON / OFF control) of the switch. Is not limited to this, the point is to connect a stop oscillator to GND during CW transmission,
Any type of switch may be used as long as it is a switch that connects the stop oscillator to the drive circuit or amplifier except during transmission.

For example, as shown in FIG.
It is also possible to provide toggle type switches 15a and 15b on the signal lines connected to a _m ′ and 2a _{m + 1} ′. This switching device 15a has one moving contact and two fixed contacts,
One moving contact is connected to the stop oscillator 2a _m ′, one of the two fixed contacts is connected to the drive circuit 3a _m ′, and the other is G
Connected to ND. The switch 15a is configured to connect the moving contact to either one of the two fixed contacts under the control of the switching controller 12 '. Similarly, the switch 15b also has one moving contact and two fixed contacts, and one moving contact is connected to the stop oscillator 2a _{m + 1} '
One of the fixed contacts is connected to the amplifier 4a _{m + 1} 'and the other is connected to GND. And this switch 15
b, the moving contact is set to 2 by the control from the switching control unit 12 '.
It is designed to connect to either one of the two fixed contacts.

Such a toggle type switch 15a,
In the example using 15b, the switching unit 15 'is controlled according to the control from the switching control unit 12' when the diagnosis of the CWD method is performed.
Switching control is performed in a and 15b, and the stop oscillator 2
The moving contacts connected to a _m 'and 2a _{m + 1} ' are forcibly GND.
Connected to a fixed contact connected to. Therefore, the potential of the stop oscillator between the transmitting side and the receiving side is set to the GND level, and the transmitting oscillator and the receiving oscillator can be electrically separated from each other. Other configurations, operations, and effects are similar to those in the case of using the switchers 10a and 10b.

Further, in the present embodiment, the switching devices 10a, 1
0b and toggle type switching devices 15a and 15b are automatically switched (open / closed) by the switching control unit 12 (12 '), but the present invention is not limited to this. For example, the CWD system is used. You may switch manually when performing a diagnosis.

(Second Embodiment) In the ultrasonic transmission / reception section of the ultrasonic diagnostic apparatus according to the second embodiment of the present invention, it is connected to the signal line between the transmission stop oscillator 2a _ma and the drive circuit 3a _ma. The bias circuit 20 that has been activated is shown in FIG.

That is, the bias circuit (diode clamp circuit) 20 shown in FIG.
a and 21b (for example, silicon diodes) and two DC power supplies 22a and 22b.

In the diode 21a, the cathode side terminal is connected to the signal line connecting the switching device 23 for switching the drive circuit 3a _ma and the transmission side stop oscillator 2a _ma, and the anode side terminal of the diode 21a is connected to the direct current The positive electrode of the power supply 22a is connected. Further, the diode 21b has an anode side terminal connected to a signal line connecting the transmission side stop oscillator 2a _ma and the switch 23, and the diode 21b is connected to the signal line.
The negative electrode of the DC power supply 22b is connected to the cathode side terminal of b. The negative electrode of the DC power supply 22b and the positive electrode of the DC power supply 22a are commonly connected to GND.

The DC power supply 22a has a predetermined positive voltage (about +0.7 when the diode 21a is a silicon diode).
(About V) is applied to the diode 21a. Further, the DC power supply 22b has a predetermined negative voltage (about -0.7 when the diode 21b is a silicon diode).
(About (V)) is applied to the diode 21b. Note that the other configurations of the transmission / reception unit and the configuration of the entire apparatus are substantially the same as those in the first embodiment, and thus description thereof will be omitted.

Next, the overall operation of the present embodiment will be described with particular emphasis on the operation of the diode clamp circuit 20.

Since the forward voltage of the silicon diode is about 0.7 (V) regardless of the current flowing through the diode, the signal line of the transmission side stop oscillator 2a _ma set based on the bias circuit 20 is set. The voltage value of is about 0 (V) because the bias voltage of +0.7 (V) applied from the DC power source 22a is dropped by about 0.7 (V) by the diode 21a.
The bias voltage of -0.7 (V) applied from b is increased by about 0.7 (V) by the diode 21b, and the bias voltage is about 0.
(V).

That is, since a low impedance voltage source of about 0 (V) can be applied to the signal line by the diode clamp circuit 20, the impedance of the signal line can be significantly reduced. The significant decrease in the impedance of the signal line of this transmitter oscillator
Capacitive crosstalk between the signal lines generated via the signal line can be significantly reduced, and as a result, noise due to the crosstalk included in the received signal can be significantly reduced.

The connection position of the cathode terminal of the diode 21a and the anode terminal of the diode 21b to the signal line is preferably the line between the stop oscillator 2a _ma and the switch 23. Because the switch 23 is OFF
This is because the signal line can be set to a low impedance even when it is not connected.

When germanium diodes or Schottky barrier diodes are used as the diodes 21a and 21b, the forward voltage of the diodes is almost constant regardless of the current flowing (for example, in the case of germanium diodes, about 0). .3 (V))
The power supply voltage values of the DC power supplies 22a and 22b may be set to some extent. In this case, the diode is turned on and acts as a low impedance element.

Further, the diode clamp circuit 20 is
Although the diode is connected to the DC power supply, the present invention is not limited to this. For example, a silicon diode can generate a DC voltage of about 0.7 (V) and a germanium diode can generate a DC voltage of about 0.3 (V). Any configuration may be used as long as it has a circuit configuration that can be applied to the diode without using a DC power supply.

Furthermore, in the present embodiment, the diode clamp circuit 20 is configured to apply both positive and negative bias voltages to set the signal line to 0 (V). However, only the positive side or only the negative side bias voltage is set. May be applied to set the signal line to 0 (V).

In the present embodiment, the diode group circuit is provided on the signal line of the transmission side stop oscillator 2 _ma , but an equivalent bias circuit is provided on the signal line of the reception side stop oscillator 2a _{(m + 1) a.} By setting the voltage value of the signal line to 0
It can also be set to (V).

(Third Embodiment) FIG. 4 shows the schematic arrangement of an ultrasonic diagnostic apparatus according to the third embodiment of the present invention. According to FIG. 4, the ultrasonic diagnostic apparatus transmits an ultrasonic signal to the body of the subject and an ultrasonic signal transmitting / receiving unit for receiving the ultrasonic signal (echo signal) reflected from the body. 31 is provided.

The ultrasonic signal transmitting / receiving unit 31 described in this embodiment has a structure capable of transmitting and receiving both pulse wave (PW) and continuous wave (CW).

That is, the ultrasonic signal transmission / reception unit 31 has an array type transducer 32 in which a plurality of transducers 32a _{1 to} 32a _n are linearly arranged. The plurality of transducers 32a ₁ ~32a _n of the array type vibrator 32, each drive circuit 3
3a _{1 ~33a n} is connected, PW in receive mode, the drive circuit 33a ₁ ~33a pulse signal sent from the _n (PW) by the transducers 32a ₁ ~32a
_{The n} is driven to transmit an ultrasonic signal toward the subject.

Amplifiers (buffer amplifiers) 34a _{1 to} 34a _n are connected to the plurality of vibrators 32a _{1 to} 32a _n , respectively, and the echo signals received by the respective vibrators 32a _{1 to} 32a _n are amplified. Amplification (impedance conversion) is performed via 34a _{1 to} 34a _n .

On the other hand, in the CW transmission / reception mode, the array type transducer 32 has transmission-only (T) transducers 32a _{1 to} 32a _m and reception-only (R) transducers 32a with a boundary in the center in the array direction. It is configured to 2 minutes to _{m + 1 ~32a n.} That is, the drive circuits 33a _{1 to} 33a
Each oscillator 32a ₁ by continuous wave (CW) sent from _m
.About.32 a _m are driven to generate ultrasonic signals toward the subject, and the reception-only transducers 32 a _{m + 1}
The echo signal received by 32a _n is amplified by amplifier 34a.
_The signal is amplified via _{m + 1 to} 34a _n .

Further, in the ultrasonic signal transmission / reception section 31 in the CW transmission / reception mode, in order to prevent crosstalk between transmission and reception, the transmission-dedicated transducers 32a adjacent to each other with the center as a boundary.
_m and the reception-only vibrator 32a _{m + 1} are set as the vibrators in the transmission / reception stop range (P). A signal line between the transmission-side stop oscillator 32a _m and the amplifier 33a _m is provided with a switcher (not shown) for controlling connection / disconnection of the stop oscillator 32a _m and the amplifier 33a _m. ing. In the PW transmission / reception mode, this switch connects the oscillator 32a _m and the amplifier 33a _m (P
In the CW transmission / reception mode, switching control is performed so that the vibrator 32a _m and the amplifier 33a _m are disconnected.

On the other hand, the ultrasonic diagnostic apparatus comprises a reception signal processing section 37, a B-mode tomographic image display section 38, and a Doppler signal calculation unit 39. The reception signal processing unit 36 is connected to each of the amplifiers 34a _{1 to} 34a _n , and in the PW transmission / reception mode, the signals amplified by the amplifiers 34a _{1 to} 34a _n are subjected to CW transmission / reception.
The signals amplified by the amplifiers 4a _{m + 1 to} 4a _n are each subjected to addition processing or the like to generate a reception signal.

One of the reception signals generated by the reception signal processing unit 36 is sent to the B-mode tomographic image display unit 37. The B-mode tomographic image display unit 37 detects the transmitted reception signal and then scan-converts it through the frame memory to generate a TV scanning B-mode image signal. Then, the B-mode tomographic image display unit 37 outputs the generated B-mode image signal to T
A B-mode tomographic image is displayed by a V monitor or the like.

The other of the received signals generated by the received signal processor 36 is sent to the Doppler signal calculation unit 38. The Doppler signal calculation unit 38 performs phase detection processing, filter processing, and the like on the received signal that has been sent, and generates a Doppler signal. Then, this Doppler signal is frequency-analyzed, and the result is analyzed by, for example, the TV of the B-mode tomographic image display unit 37.
The blood flow velocity information is displayed on the monitor (superimposed on the tomographic image).

Here, the CW which is a characteristic part of this embodiment
The connected schematic configuration of an amplifier 34a m + ₁ to the transmitting-side stop transducers 32a connected amplifiers 34a _m and the receiving side _m stopped transducers 32a m + ₁ in the transceiver shown in FIG.

According to FIG. 5, the amplifier 32a _m is composed of a buffer amplifier 40 which performs impedance conversion with an amplification factor of 1. The buffer amplifier 40 includes a power supply section 41.
To the bias voltage (+ V _CC
(V), -V _EE (V); V _CC and -V _EE are determined by the amplitude of the input signal), but are always supplied when the device is operating regardless of CW transmission / reception and PW transmission / reception. It is like this. In addition, the transducer 32 for transmission
a _{1 to} 32 a _{m -1} and reception-dedicated transducers 32 a _{m + 2 to} 32
amplifier 34a is connected to a _{n 1} ~34a _m-1 and 34
The configuration of a _{m + 2 to} 34 a _{n is the same} as that of the amplifier 34 a _m .

On the other hand, the amplifier 34a _{m + 1} is the amplifier 34a
_The buffer amplifier 42 is configured to perform impedance conversion with an amplification factor of 1 like _m.
The bias voltage supply line of the
Is connected to the power supply unit 41 via.

The bias voltage control section 43 supplies the buffer amplifier 42 with the bias voltage (+ V _CC , -V _EE ) for driving the buffer amplifier, which is sent from the power supply section 41 when the apparatus is operating, to the input section (panel switch) not shown. Control section) and the like to control in accordance with a PW / CW mode signal.

[0069] That is, the bias voltage controller 43, a bias voltage (+ V _CC, -V _EE) was supplied to the buffer amplifier 42 only PW reception mode, in the CW reception mode, the bias voltage (+ V _CC, - V _EE ) is not supplied to the buffer amplifier 42 (supply is stopped, that is, the bias voltage is (+0 (V), −0 (V)).

Next, the overall operation of this embodiment will be described with particular emphasis on the operation of the amplifiers 34a _m and 34a _{m + 1} .

When various diagnoses are performed using pulse waves (PW) (PW transmission / reception), for example, PWD (Pulse Doppler) type diagnosis is performed, the PW mode signal from the input unit is changed to the bias voltage control unit 43. Therefore, the bias voltage (+ V _CC , −V _EE ) is supplied to the buffer amplifier 42. As a result, the buffer amplifier 42 biases O
N, and all the amplifiers 34a _{1 to} 34a _n are ready to be driven.

On the other hand, at the time of CW transmission / reception, C
Since the W mode signal is sent to the bias voltage control unit 43, the bias voltage (+ V _CC , −) is applied to the buffer amplifier 42.
V _EE ) is not supplied (supply is stopped), the buffer amplifier 42
Turns off the bias. Therefore, the amplifier 34a ₁
Of ～34A _n, only the amplifier 34a _{m + 1} connected to the receiver stop transducers 32a _{m + 1} is the drive stop state, the other amplifiers _{34a 1 ~34a m, 34a m +} 2 ~34a
_n remains drivable.

That is, since the buffer amplifier 40 connected to the signal line of the transmission side stop oscillator 32a _m is always biased ON, the impedance of the output line of the buffer amplifier 40 is lowered due to the characteristics of the buffer amplifier, and as a result, It is possible to reduce the capacitive crosstalk between the signal lines generated via the signal line.

Further, in the CW transmission / reception mode,
Since the buffer amplifier 42 connected to the signal line of the reception-side stop oscillator 32a _{m + 1} has the bias OFF, the crosstalk signal received at the input side of the buffer amplifier 42 should be blocked by the output of the buffer amplifier 42. You can That is, the crosstalk signal is not included in the output line of the reception-side stopped oscillator 32a _{m + 1} (buffer amplifier 42), and the reception-side dedicated oscillator 32 is connected via the output line.
_m + 2 _{~32a n} (buffer amplifier) 34 _m + 2 ~34
The crosstalk signal mixed in the output line of a _n ) is significantly reduced.

As described above, according to the present embodiment,
During CW transmission / reception, by keeping the bias of the amplifier connected to the transmission side stop oscillator ON and setting only the bias of the amplifier connected to the reception side stop oscillator OFF, an extra circuit configuration can be achieved. Crosstalk can be effectively reduced with almost no addition, and as a result, noise due to crosstalk contained in the received signal can be significantly reduced.

(Fourth Embodiment) Connected to the signal line between the transmission-side stop oscillator 2a _mb and the drive circuit 3a _mb in the ultrasonic transmission / reception section of the ultrasonic diagnostic apparatus according to the fourth embodiment of the present invention. FIG. 6 shows a part of the ultrasonic signal transmission / reception unit including the shunt circuit.

That is, the ultrasonic signal transmission / reception unit including the shunt circuit 50 shown in FIG. 6 is provided on the signal line between the transmission side transducer 2a _mb and the switch 23b for switching control of the drive circuit 3a _mb . A diode 51 that blocks the flow of a signal from the oscillator side to the drive circuit side, and a shunt switch 50 provided on a branch line L ₁ that is branched from the signal line between the diode 51 and the oscillator 2a _mb.
a and a switching control unit 52 for controlling connection / disconnection of the switch 23b and the shunt switch 50a.

The terminal opposite to the signal line side connection terminal of the shunt switch 50a is connected to GND. In addition,
The other configurations of the transmission / reception unit and the configuration of the entire apparatus are substantially the same as those in the first embodiment, and thus the description thereof will be omitted.

Next, the overall operation of this embodiment will be described with particular emphasis on the operation of the shunt circuit 50.

During CW transmission / reception, in the switch 23b, the transmission side transducer 2a _mb and the drive circuit 3a _mb are not connected (that is, the transmission side transducer 2a _mb stops transmitting) under the control of the switching control unit 52. Switching control (OFF)
Controlled).

Further, during CW transmission / reception, the shunt switch 50a is ON (connected) controlled according to the control from the switching control section 52, and as a result, the transmission side stop vibrator 2
Forcibly shorts (shunts) the signal line connected to a _mb to GND.

As a result, the potential of the stop oscillator on the transmission side is GN.
Since the oscillator is set to the D level, the transmitter-side oscillator and the receiver-side oscillator are electrically separated. Therefore,
For example, capacitive crosstalk that is generated by the vibration of adjacent transducers and mixes from the transmitting side to the receiving side is greatly reduced,
As a result, it is possible to significantly reduce the noise included in the received signal due to the crosstalk.

The type of shunt switch is FE
Various switching elements such as T and transistors can be used.

By the way, since the PW is transmitted and received by each transducer, it is necessary to remove the signal charge remaining in the transducer at the time of transmission when receiving the echo signal. Therefore, there is a diagnostic device in which each vibrator is provided with a circuit for removing the signal charge remaining in the vibrator during transmission.

Even in the configuration capable of transmitting and receiving both PW and CW shown in abbreviated form in FIG. 4, it is possible to provide each transducer with the above-mentioned signal charge removing circuit. It can also be provided with a charge circuit.

Here, an example of an ultrasonic signal transmitting / receiving unit provided with a signal charge removing circuit and a shunt circuit connected to a transmission side stop oscillator (vibrator during PW transmission / reception) 32a _m ′ that stops transmission during CW transmission / reception The parts are shown in FIG. 7.

That is, the ultrasonic signal transmission / reception unit includes a switching device 23 for switching control between the transducer 32a _m 'and the drive circuit 33a _m '.
A diode 55 provided on a signal line between the oscillator 55 and the drive circuit side to prevent a signal from flowing from the oscillator side, and a branch branched from the signal line between the diode 55 and the oscillator 32a _m ′. It has a diode 56 connected to the signal line and a switch (switch) 57 connected in series with the diode 56, and the terminal opposite to the diode connection terminal of the switch 57 is connected to GND.
The diode 57 is connected to the oscillator 32a from the GND side.
It is provided so as to block the flow of signals to _m '.

Further, the oscillator 32a _m 'and the diode 55
A shunt switch (FET switch) 58 is provided on a branch line L ₂ that is branched from a signal line that connects to and the signal line side connection terminal of the shunt switch 58 is connected to GND.

Further, the ultrasonic signal transmission / reception section has a switching control section 59 for controlling connection / disconnection of the switch 23c, the switch 57 and the shunt switch 58.

According to FIG. 7, the switching unit 23c is controlled by the switching control unit 59 during the PW transmission, and the switching unit 23c controls the vibrator 3c.
2a _m 'and drive circuit 33a _m ' are switched and controlled (ON control) so that they are in a connected state.
connected signal line and GND _m 'is the switching control so that the disconnection (OFF control). When the PW is received, the switch 23c is controlled to switch (OFF control) so that the vibrator 32a _m ′ and the drive circuit 33a _m ′ are not connected in accordance with the control from the switch controller 59. The switch 57 is controlled to switch (ON control) so that the signal line connected to the vibrator 32a _m ′ and the GND are connected.

At this time, the oscillator 32a _m 'is the diode 5
Since it is connected to GND via 6, all the signal charges remaining in the oscillator 32a _m 'at the time of transmission are diode 5
6. Flow to GND via switch 57. As a result, all the residual charges of the vibrator 32a _m 'are removed.

During PW transmission / reception, the shunt switch 58 is controlled to be OFF (not connected) under the control of the switching control section 59.

On the other hand, during CW transmission / reception, the switch 2
The switching control (OFF control) of 3c is performed under the control of the switching control unit 59 so that the vibrator 32a _m ′ and the drive circuit 33a _m ′ are not connected. Then, the shunt switch 58 is turned on according to the control from the switching control unit 59.
(Connection) is controlled, and as a result, the signal line connected to the oscillator (that is, the transmission-side stop oscillator) 32a _m ′ is forcibly short-circuited (shunted) to GND.

As a result, the potential of the vibrator 32a _m 'is GND.
Since the level is set, the oscillator on the transmitting side and the oscillator on the receiving side are separated in circuit. Therefore, for example, capacitive crosstalk that is generated due to vibration of adjacent transducers and that mixes from the transmission side to the reception side is significantly reduced, and as a result, the noise caused by the crosstalk included in the reception signal is significantly reduced. Can be made.

In each of the above-described embodiments, the array-type transducer is divided into a transmission-side transducer and a reception-side transducer with the center as a boundary, and one transmission-only transducer and one reception-only transducer adjacent to the boundary are provided. The vibrators are set as transmission / reception stop vibrators, but the present invention is not limited to this, and the point is that C
At least one transmission / reception stop oscillator may be set between the oscillator that transmits CW and the oscillator that receives CW during W transmission / reception.

For example, as shown in FIGS. 8A and 8B, at least between the transmission oscillator (T) and the reception oscillator (R) so that the transmission oscillator and the reception oscillator are not adjacent to each other. Any configuration can be implemented as long as the configuration is such that one transmission / reception stop oscillator (G) is arranged (see oscillator group a and oscillator group b).

[0097]

As described above, according to the present invention, the potential of the transmission / reception stop oscillator is set to GND for the capacitive impedance component causing the capacitive crosstalk, and Since the signal line is reduced by setting it to a low impedance or the like, it is possible to significantly reduce the capacitive crosstalk mixed in the received signal. As a result, it is possible to reduce the noise component due to the crosstalk included in the received signal.

Further, as described above, since the capacitive crosstalk itself is reduced in the received signal, it is possible to set the number of stop oscillators to a necessary minimum as compared with the conventional case.
As a result, it is possible to increase the number of actual driving vibrators as compared with the related art, and it is possible to improve the transmission / reception sensitivity and the ultrasonic wave propagation characteristics.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit for explaining a modified example of the first embodiment.

FIG. 3 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit for explaining a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an ultrasonic diagnostic apparatus according to a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit for explaining a third embodiment.

FIG. 6 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit for explaining a fourth embodiment.

FIG. 7 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit for explaining a modification of the fourth embodiment of the present invention.

FIG. 8 is a diagram showing an array configuration of ultrasonic transducers.

FIG. 9 is a schematic configuration diagram showing a main part of an ultrasonic signal transmission / reception unit of a conventional ultrasonic diagnostic apparatus.

FIG. 10 is a diagram for explaining problems in the ultrasonic signal transmitting / receiving unit of the conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

1,31 ultrasonic signal transmitting and receiving unit 2, 32 ultrasonic transducers 2a ₁ ~2a _m, 32a ₁ ~ transmission dedicated transducer _{2a m + 1 ~2a n, 32a} m + 1 ~32a n reception dedicated transducer 2a _m, 2a _{m + 1} , 2a _ma , 2a _{(m + 1) a} , 32a _m , 3
2a _{m + 1} stops vibrator _{3a 1 ~3a m, 3a mb,} 33a 1 ~33a n, 33a
_mb drive circuit 4a _{m + 1 to} 4a _n , 34a _{m + 1 to} 34a _n amplifier 6,36 reception signal processing unit 7,37 B mode tomographic image display unit 8,38 Doppler signal calculation unit 10a, 10b, 15a, 15b switching 11a, 11b Switching section 12 Switching control section 20 Bias circuit 21a, 21b Diode 22a, 22b DC power supply 40 Buffer amplifier 41 Power supply section 42 Buffer amplifier 43 Bias voltage control section 50 Shunt circuit 50a Shunt switch 51 Diode 52 Switching control section 55 Diode 56 diode 57 switch 58 shunt switch 59 switching control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Utsumi 1385-1 Shimoishigami, Otawara-shi, Tochigi Stock company Toshiba Nasu factory (72) Inventor Yasushi Ueki 1385-1,385 Shimoishi, Otawara, Tochigi Stock company Toshiba Nasu factory

Claims (8)

[Claims] 1. A continuous wave signal reflected from the subject in response to a continuous wave ultrasonic signal transmitted to the subject, and a living body of the subject based on the received continuous wave signal. An ultrasonic diagnostic apparatus for obtaining information has an array-type transducer in which a plurality of transducers are arrayed, and the plurality of transducers forming the array-type transducer are dedicated to transmission for performing only the transmission processing of the continuous wave signal. The continuous wave signal is transmitted and received by at least one vibrator which is divided into a vibrator and a receive-only vibrator that performs only the reception processing of the continuous wave. And a crosstalk reduction circuit connected to the signal line of the stop oscillator for reducing crosstalk mixed in the received continuous wave signal. Ultrasonic diagnostic apparatus. 2. The crosstalk reducing circuit is connected to a signal line of the stop oscillator to connect the stop oscillator to GND.
The ultrasonic diagnostic apparatus according to claim 1, which is a setting circuit for setting a potential. 3. The ultrasonic diagnostic apparatus according to claim 1, wherein the crosstalk reducing circuit is a low impedance circuit that is connected to a signal line of the stop oscillator and reduces impedance of the signal line. 4. The ultrasonic diagnostic apparatus according to claim 3, wherein the impedance reduction circuit includes a low impedance bias source circuit that applies a low impedance bias voltage source of approximately 0 volt to the signal line. 5. The stop oscillator includes a transmitter oscillator on the transmission side set from the oscillators dedicated to transmission and a receiver oscillator on the reception side set from the oscillators dedicated to reception. An amplifier for signal amplification is connected to the vibrator, and the crosstalk reduction circuit maintains the bias voltage of the amplifier connected to the transmission side stop vibrator at ON.
The ultrasonic diagnostic apparatus according to claim 1, further comprising a voltage control circuit that turns off only a bias voltage of an amplifier connected to the reception side stop oscillator. 6. The ultrasonic diagnostic apparatus according to claim 5, wherein the amplifier is a buffer amplifier having an amplification factor of about 1 and performing impedance conversion. 7. The stop oscillator includes at least a transmitter stop oscillator set from among the transmitter-only oscillators, and the crosstalk reduction circuit is connected to a signal line of the transmitter stop oscillator. The ultrasonic diagnostic apparatus according to claim 1, further comprising a shunt circuit for forcibly shunting the transmission-side stop oscillator to GND. 8. A continuous wave signal reflected from the subject according to an ultrasonic signal of either the continuous wave or the pulse wave transmitted to the subject is received, and the received continuous wave signal is obtained. In an ultrasonic diagnostic apparatus that obtains biological information of the subject based on the above-mentioned continuous wave signal, the arrayed vibrator has an arrayed vibrator in which a plurality of vibrators are arranged. At least one of the parts divided into a transmission-dedicated oscillator that performs only the transmission processing of the continuous wave at the time of transmission and reception and a reception-dedicated oscillator that performs only the reception processing of the continuous wave Is set as a stop oscillator in which the transmission or reception of the continuous wave is stopped, and a circuit for removing the signal charge remaining in each of the plurality of oscillators at the time of transmitting / receiving the pulse wave is provided for each oscillator. Provided in connection to the child, the ultrasonic diagnostic apparatus characterized by comprising a shunt circuit for shunting a signal line connecting the transmitting side stop oscillator and the signal charge removal circuit to GND.