JP2010081966A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit two types of ultrasonic waves having a same frequency and change pattern but having mutually inverted phases highly accurately compared with conventional ones. <P>SOLUTION: A transmission transformer 61 includes a primary-side coil 61a and a secondary-side coil 61b, and applies a voltage induced at the secondary-side coil 61b, to an ultrasonic transducer 7. A transistor 62 is connected to be switchable between a potential point whose voltage is VP and one end of the primary-side coil 61a, a transistor 63 is connected to be switchable between a grounded potential point and the one end of the primary-side coil 61a, a transistor 64 is connected to be switchable between the potential point whose voltage is VP and the other end of the primary-side coil 61a, and a transistor 65 is connected to be switchable between the grounded potential point and the other end of the primary-side coil 61a. A control circuit 66 simultaneously turns on the transistors 62 and 65 or simultaneously turns on the transistors 63 and 64. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus for diagnosing a subject using reflection of an ultrasonic wave transmitted from an ultrasonic transducer on the subject.

  2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus that images a harmonic (harmonic) component is known. In this method, a component having a frequency that is an integral multiple (usually twice) of the transmission frequency among reflected ultrasonic waves from a living body is used for imaging. In order to obtain harmonic components for imaging, two transmissions are performed with the phases reversed in the same direction. Then, the reflected waves related to the two transmissions are added to each other to cancel the fundamental wave component and extract the harmonic component.

In order to perform the transmission as described above, a transmission circuit as shown in FIG. 6 is conventionally known. In this transmission circuit, a transformer 11 having two primary windings and one secondary winding having different winding directions is used. Then, by selectively energizing the two primary windings of the transformer 11 with the two transistors 12 and 13, pulses having different polarities can be supplied to the ultrasonic transducer 14. Then, by combining such pulses having different polarities and supplying them to the ultrasonic transducer 14, two types of ultrasonic signals whose phases are reversed can be transmitted.
JP-A-7-336198

  However, since the amplitude of the signal for driving the ultrasonic transducer reaches ± 100 V in some cases, it is desirable that the gain in the transformer 11 is large. On the other hand, the number of ultrasonic probes has been increasing in recent years, and some ultrasonic probes have 192 ultrasonic transducers. Since the transformers 11 must have the same number as the ultrasonic transducers, an increase in size must be avoided. For this reason, the transformer 11 is expected to have a large gain while being small, and the number of turns on the primary side is extremely reduced. For example, the primary winding may be about 1 to 2 turns with respect to the core.

  Such a transformer 11 has poor winding accuracy and large variations in leakage inductance. For this reason, even if each of the two primary windings is energized in the same manner, there is a difference in the rising characteristics and the falling characteristics of the pulses excited on the secondary side, and two transmissions in which only the phases are inverted from each other are performed. I can't do it. For this reason, even if the reflected waves related to the two transmissions are added together, the fundamental wave component cannot be sufficiently canceled out.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to improve the symmetry of the waveforms of two types of ultrasonic waves whose phases are reversed from each other.

  The ultrasonic diagnostic apparatus according to the first aspect of the present invention includes an ultrasonic transducer, one primary winding and one secondary winding, and a voltage induced in the secondary winding. And a supply means for supplying a predetermined time-varying bipolar current to the primary winding.

  The ultrasonic diagnostic apparatus according to the second aspect of the present invention includes an ultrasonic transducer, one primary winding and one secondary winding, and a voltage induced in the secondary winding. Are applied to the ultrasonic transducer, a first time-varying bipolar current, and a second time-changing bipolar current whose phase is reversed with respect to the first time-varying time series. Supply means for supplying to the side winding, and in response to an echo of the ultrasonic wave transmitted from the ultrasonic transducer in response to the first time-varying bipolar current being supplied to the primary side winding. An echo signal output from the ultrasonic transducer and an ultrasonic echo transmitted from the ultrasonic transducer in response to the second time-varying bipolar current being supplied to the primary winding. And adding the echoes output by the ultrasonic transducer Therefore comprising extracting means for extracting a harmonic component contained in the echo signal, and an imaging means for imaging the source of the echo on the basis of the harmonic component extracted by the extraction unit.

  The ultrasonic diagnostic apparatus according to the third aspect of the present invention includes an ultrasonic transducer, one primary winding and one secondary winding, and a voltage induced in the secondary winding. , A first switch connected between the first potential point of the first potential and the first end of the primary winding, and the first switch A second switch connected between a second potential point having a second potential lower than the first potential and the first end, a third potential point having the first potential, and the first potential point. A third switch connected between the second end of the secondary winding and a fourth switch connected between the fourth potential point of the third potential and the second end. And the first to fourth switches are driven so that the first and fourth switches are simultaneously turned on, and the second and third switches are simultaneously turned on. The phase of the pattern for turning on / off the drive circuit, the first and fourth switches, and the second and third switches is different between the first transmission time and the first transmission time. And a control means for controlling the drive circuit so as to be inverted at the time of transmission.

  According to the present invention, the symmetry of the waveforms of two types of ultrasonic waves whose phases are reversed from each other is improved as compared with the conventional case.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to this embodiment.

  The ultrasonic diagnostic apparatus shown in FIG. 1 includes a diagnostic apparatus main body 100 and an ultrasonic probe 200.

  The diagnostic apparatus main body 100 further includes a system controller 1, a beam former 2, a scan converter 3 and a display device 4, a transmission beam former 5, a plurality of transmission circuits 6, a plurality of reception circuits 8 and a beam former 9. The ultrasonic probe 200 further includes a plurality of ultrasonic transducers 7.

  The system controller 1 transfers delay data and transmission waveform data to the transmission beamformer 5. The transmission beamformer 5 controls each of the plurality of transmission circuits 6 so as to form a required ultrasonic beam based on the delay data and the transmission waveform data. The plurality of transmission circuits 6 supply transmission signals to each of the plurality of ultrasonic transducers under the control of the transmission beam former 5.

  The plurality of ultrasonic transducers 7 receive supply of transmission signals from the plurality of transmission circuits 6 and individually radiate ultrasonic waves corresponding to the transmission signals. The plurality of ultrasonic transducers 7 are arranged in a predetermined arrangement, and a required ultrasonic beam is formed by synthesizing ultrasonic waves individually radiated from the plurality of ultrasonic transducers 7. The plurality of ultrasonic transducers 7 outputs an electrical echo signal corresponding to the reflected wave when the reflected wave generated by the reflection of the ultrasonic beam at the boundary of the acoustic impedance is incident.

  The subarray beamformer 9 delays and adds echo signals output from each of the plurality of ultrasonic transducers 7 to obtain an echo signal related to a required reception beam. Further, the beam former 2 performs a process of extracting a harmonic component from the echo signal when the pulse inversion video method is to be applied. That is, the beamformer 2 extracts a harmonic component by adding two echo signals based on two transmissions whose phases are shifted by 180 degrees as described later and canceling the fundamental component. The scan converter 3 converts the echo signal obtained by the beamformer 2 into data suitable for display on the display device 4. Thereby, the display device 4 displays an ultrasonic image based on the data converted by the scan converter 3.

  Now, the plurality of transmission circuits 6 all have the same configuration. FIG. 2 is a diagram showing the configuration of the transmission circuit 6.

  As shown in FIG. 2, the transmission circuit 6 includes a transmission transformer 61, transistors 62 to 65, and a control circuit 66.

  The transmission transformer 61 includes a primary winding 61a and a secondary winding 61b one by one. One end of the primary side winding 61 a is connected to a potential point where the voltage is VP through the transistor 62 and grounded through the transistor 63. The other end of the primary winding 61 a is connected to a potential point where the voltage is VP through the transistor 64 and is grounded through the transistor 65. The secondary winding 61b has one end connected to the ultrasonic transducer 7 and the other end grounded.

  The transistors 62 to 65 are individually turned on / off according to control signals individually supplied from the control circuit 66. Here, P-channel FETs (field-effect transistors) are used as the transistors 62 and 64, and N-channel FETs are used as the transistors 63 and 65, respectively. However, the transistors 62 and 64 can be replaced with Nch FETs arranged in the same direction as the transistors 63 and 65.

  The control circuit 66 controls the transistors 62 to 65 so as to excite a transmission signal having a required waveform to the secondary winding 61b under the control of the transmission beamformer 5.

  Next, the operation of the ultrasonic diagnostic apparatus configured as described above will be described. The operation of this ultrasonic diagnostic apparatus is different from the conventional operation in the operation related to the driving of the ultrasonic transducer 7 at the time of ultrasonic transmission. The description of the operation is omitted.

  FIG. 3 is a timing chart showing a sequence for transmitting a waveform inverted by 180 degrees in the first and second transmissions.

  In a period P1 from time T1 which is the first transmission start timing to time ta, the control circuit 66 turns on the transistors 62 and 65 and turns off the transistors 63 and 64. Then, current flows through the transistor 62, the primary winding 61a, and the transistor 65 in the direction of the arrow A1 shown in FIG.

  Assuming that the time point when the period P1 ends is a time point T2, the control circuit 66 turns off all the transistors 62 to 65 from the time point T2 until the time tb elapses.

  Assuming that a time point Tb has elapsed from the time point T2 is a time point T3, the control circuit 66 turns off the transistors 62 and 65 and turns on the transistors 63 and 64 in a period P2 from the time point T3 until the time ta passes. . Then, a current flows through the transistor 64, the primary winding 61a, and the transistor 63 in the direction of the arrow A2 shown in FIG.

  If the time point when the period P2 ends is a time point T3, the control circuit 66 turns off all the transistors 62 to 65 from the time point T3 to the time point T5 which is the second transmission start timing.

  In a period P3 from time T5 to time ta, the control circuit 66 turns off the transistors 62 and 65 and turns on the transistors 63 and 64. Then, a current flows through the transistor 64, the primary winding 61a, and the transistor 63 in the direction of the arrow A2 shown in FIG.

  Assuming that the time point when the period P3 ends is a time point T6, the control circuit 66 turns off all the transistors 62 to 65 from the time point T6 until the time tb elapses.

  Assuming that the time point Tb has elapsed from the time point T6 as the time point T7, the control circuit 66 turns on the transistors 62 and 65 and turns off the transistors 63 and 64 in the period P4 from the time point T7 until the time ta passes. . Then, current flows through the transistor 62, the primary winding 61a, and the transistor 65 in the direction of the arrow A1 shown in FIG.

  From time T8 when the period P4 ends, the control circuit 66 turns off the transistors 62 to 65.

  In this way, in periods P1 and P4 and periods P2 and P3, a current in the opposite direction is generated in the primary winding 61a. Therefore, the voltage induced in the secondary winding 61b is the period P1, P4. In the periods P2 and P3, the directions are reversed. As a result, the transmission signal supplied from the secondary winding 61b to the ultrasonic transducer 7 has the waveform shown in FIG. In any of the periods P1 to P4, the current is generated in the common primary winding 61a, and the voltage applied to the primary winding 61a is constant at the voltage VP. The absolute value of the amplitude of the transmission signal is equal in any of the periods P1 to P4. Thus, only the phase is inverted between the waveform of the transmission signal at the first transmission from time T1 to time T4 and the waveform of the transmission signal at the second transmission from time T5 to time T8. .

  Thus, according to the present embodiment, the symmetry of the two transmission waveforms can be sufficiently ensured without being affected by the leakage inductance of the transmission transformer 61. As a result, by adding the two echo signals respectively obtained in response to these two transmissions, it is possible to sufficiently cancel out the fundamental wave component and extract the harmonic component satisfactorily.

  This embodiment can be variously modified as follows.

  A part of the circuit mounted on the diagnostic apparatus main body 100 may be provided on the ultrasonic probe 200 side. For example, the ultrasonic probe 200 may include the transmission circuit 6 and the reception circuit 8. Further, in addition to the transmission circuit 6 and the reception circuit 8, the transmission beam former 5 can be provided in the ultrasonic probe 200.

  The transistors 64 and 65 may be connected to a potential point having a voltage that is significant and different from the voltage VP. However, the voltages at the potential points to which the transistors 64 and 65 are connected are the same.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. The figure which shows the structure of the transmission circuit 6 in FIG. The timing chart which showed the sequence which transmits the waveform reversed 180 degree | times by the 1st transmission and the 2nd transmission. The figure which shows a mode that an electric current arises in the primary side coil | winding 61a in the period P1, P4 in FIG. The figure which shows a mode that an electric current arises in the primary side coil | winding 61a in the period P2, P3 in FIG. The figure which shows an example of the conventional structure of a transmission circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... System controller, 2 ... Beam former, 3 ... Scan converter, 4 ... Display apparatus, 5 ... Transmission beam former, 6 ... Transmission circuit, 7 ... Ultrasonic transducer, 8 ... Reception circuit, 61 ... Transmission transformer, 61a ... Primary winding, 61b ... Secondary winding, 62-65 ... Transistor, 66 ... Control circuit, 100 ... Diagnostic device body, 200 ... Ultrasonic probe.

Claims (4)

An ultrasonic transducer,
A transformer having a primary winding and a secondary winding one by one, and applying a voltage induced in the secondary winding to the ultrasonic transducer;
An ultrasonic diagnostic apparatus comprising: supply means for supplying a bipolar current having a predetermined time change to the primary side winding. An ultrasonic transducer,
A transformer having a primary winding and a secondary winding one by one, and applying a voltage induced in the secondary winding to the ultrasonic transducer;
Supply means for supplying a first time-varying bipolar current and a second time-changing bipolar current having a phase reversed from that of the first time change to the primary winding in time series;
An echo signal output from the ultrasonic transducer in response to an ultrasonic echo transmitted from the ultrasonic transducer in response to the first time-varying bipolar current being supplied to the primary winding. And the ultrasonic transducer outputs in response to an ultrasonic echo transmitted from the ultrasonic transducer in response to the second time-varying bipolar current being supplied to the primary winding. Extraction means for extracting a harmonic component contained in the echo signal by adding an echo; and
An ultrasonic diagnostic apparatus comprising: an imaging unit configured to image the source of the echo based on the harmonic component extracted by the extracting unit. An ultrasonic transducer,
A transformer having a primary winding and a secondary winding one by one, and applying a voltage induced in the secondary winding to the ultrasonic transducer;
A first switch connected between a first potential point of a first potential and a first end of the primary winding;
A second switch connected between a second potential point of a second potential smaller than the first potential and the first end;
A third switch connected between a third potential point of the first potential and a second end of the primary winding;
A fourth switch connected between a fourth potential point of the third potential and the second end;
A driving circuit for driving the first to fourth switches so that the first and fourth switches are simultaneously turned on, and the second and third switches are simultaneously turned on;
The phase of the pattern for turning on / off the first and fourth switches and the second and third switches is different between a first transmission time and a second transmission time different from the first transmission time. An ultrasonic diagnostic apparatus comprising control means for controlling the drive circuit so as to be reversed at each time.   The ultrasonic diagnostic apparatus according to claim 3, wherein the second potential is a ground potential.

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