JP2007111257A - Ultrasonic diagnostic device and ultrasound probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress heat generation by efficient transmission in an ultrasonic diagnostic device for diagnosing a patient utilizing ultrasonic waves transmitted from an ultrasonic vibrator and an ultrasonic probe utilizing the ultrasonic diagnostic device. <P>SOLUTION: Constant current of positive polarity and negative polarity is output by a positive power source 9 and a constant current source part 12, and a negative power source 10 and a constant current source part 13, and applying of the constant current of positive polarity and that of negative polarity to the ultrasonic vibrator 11 can be switched by transistors 7 and 8. Then, a transmission waveform generator 2, an enable signal generator 3 and a level shifter 5 close the transistor 7 continuously or intermittently in a first period P1, and open it continuously in a second period P2 which is after the first period P1. The transmission waveform generator 2, an enable signal generator 4 and a level shifter 6 open the transistor 8 continuously in the first period P1, and close it continuously or intermittently in the second period. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that diagnoses a subject using ultrasonic waves transmitted from an ultrasonic transducer, and an ultrasonic probe that can be used in the ultrasonic diagnostic apparatus.

  In recent years, as means for transmitting ultrasonic waves from the transducer in the ultrasonic probe, a positive direction switch for current discharge and a negative direction switch for suction are provided, and a circuit configuration for generating a rectangular pulse by alternately switching them is provided. An ultrasonic diagnostic apparatus is generally used.

  FIG. 5 is a diagram showing a conventional configuration example of this type of ultrasonic diagnostic apparatus. FIG. 6 is a diagram showing signal waveforms and timing relationships of the respective parts in FIG.

  FIG. 5 shows only the configuration related to the transmission of ultrasonic waves. In recent years, an ultrasonic diagnostic apparatus generally includes a two-dimensional array or a three-dimensional array of multichannel transducers and displays a tomographic image in real time. For this reason, the transmission unit also has a corresponding number of channels, but FIG. 5 shows only one of them.

  A conventional ultrasonic diagnostic apparatus will be described below with reference to FIGS. 5 and 6. In this description, the expressions “ON” and “OFF” are used for convenience as the state of the FET. The ON state indicates a state where the source-drain impedance is low, and the state where the impedance is high contrary to the OFF state.

  The ultrasonic diagnostic apparatus shown in FIG. 5 includes an apparatus main body 101 and an ultrasonic probe 104. The apparatus main body 101 further includes a reference signal generator 1. The ultrasonic probe 104 further includes level shifters 5 and 6, transistors 7 and 8, a positive power source 9, a negative power source 10, an ultrasonic transducer 11, and a transmission waveform generator 31. Note that a P-type field effect transistor (FET) is applied as the transistor 7. As the transistor 8, an N-type field effect transistor is applied.

  The reference signal generator 1 outputs a reference signal a1. As shown in FIG. 6, the reference signal a1 is a signal that repeats a high level and a low level at a constant repetition period. The level shifter 5 outputs a signal a2 obtained by converting the reference signal a1 into a waveform level that can be turned ON / OFF between the source and drain of the transistor 7. Similarly, the level shifter 6 outputs a signal a3 obtained by converting the reference signal a1 into a waveform level that can be turned ON / OFF between the source and drain of the transistor 8. A positive power source 9 is connected to the source side of the transistor 7, and a negative power source 10 is connected to the source side of the transistor 8.

  When the signal a2 is low level, the transistor 7 is turned on, and when the signal a2 is high level, the transistor 7 is turned off. On the other hand, the transistor 8 is turned off when the signal a3 is at a low level, and the transistor 8 is turned on when the signal a3 is at a high level. Therefore, a signal a4 having a waveform as shown in FIG. 6 is generated at the drain terminals of the transistors 7 and 8 due to the waveforms of the signal a2 and the signal a3, and the ultrasonic transducer 11 is excited by the signal a4.

Strictly speaking, the waveform of the signal a4 has rise and fall times and has an inclination of the waveform, but is ignored here because it is sufficiently short with respect to the ultrasonic transmission signal width.
JP 2001-258889 A

  Thus, conventionally, since the rising and falling waveforms of the signal applied to the ultrasonic transducer are steep, high-order harmonic components are included.

  Normally, this type of harmonic component is not used because it falls outside the ultrasonic signal bandwidth. Therefore, the transmission power is unnecessarily increased due to the harmonic component, which is part of the heat generation factor of the transmission circuit and the ultrasonic transducer.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide an ultrasonic diagnostic apparatus and an ultrasonic probe that can suppress heat generation by efficient transmission.

  In order to achieve the above object, the present invention outputs positive and negative constant currents in an ultrasonic diagnostic apparatus that diagnoses a subject using ultrasonic waves transmitted from an ultrasonic transducer. First and second power supply means, first switch means for opening and closing a connection between the ultrasonic vibrator and the first power supply means, and connection between the ultrasonic vibrator and the second power supply means The second switch means for opening and closing and the first switch means are closed continuously or intermittently in the first period and continuously in the second period after the first period. First control means that opens at a time, and second control means that opens the second switch means continuously in the first period and closes it continuously or intermittently in the second period; Equipped with.

  In order to achieve the above object, the present invention provides an ultrasonic vibrator, first and second power supply means for outputting positive and constant polarity constant currents, the ultrasonic vibrator, and the first A first switch means for opening and closing a connection with the power supply means, a second switch means for opening and closing a connection between the ultrasonic transducer and the second power supply means, and the first switch means. A first control means that continuously or intermittently closes in a period of 1 and opens continuously in a second period after the first period; and the second switch means, The ultrasonic probe is configured to include a second control unit that continuously opens in the first period and continuously or intermittently closes in the second period.

  According to the present invention, heat generation can be suppressed by efficient transmission.

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

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram showing signal waveforms and timing relationships at various parts in FIG. 1, the same elements as those in FIG. 5 are denoted by the same reference numerals.

  FIG. 1 shows only the configuration related to the transmission of ultrasonic waves. In recent years, an ultrasonic diagnostic apparatus generally includes a two-dimensional array or a three-dimensional array of multichannel transducers and displays a tomographic image in real time. For this reason, the transmitting unit also has a corresponding number of channels, but FIG. 1 shows only one of them.

  The ultrasonic diagnostic apparatus according to the first embodiment includes an apparatus main body 101 and an ultrasonic probe 102 as shown in FIG. The apparatus main body 101 further includes a reference signal generator 1. The ultrasonic probe 102 further includes a transmission waveform generator 2, enable signal generators 3 and 4, level shifters 5 and 6, transistors 7 and 8, a positive power source 9, a negative power source 10, an ultrasonic transducer 11, and a constant current source unit 12. , 13.

  The reference signal generator 1 generates a reference signal. This reference signal is transmitted to the ultrasonic probe 102 via a signal line in a cable connecting the apparatus main body 101 and the ultrasonic probe 102. The reference signal is input to the transmission waveform generator 2.

  The transmission waveform generator 2 generates a signal b1 having a transmission waveform based on the reference signal. The signal b1 is a signal that becomes low level continuously or intermittently in the first period and becomes high level continuously or intermittently in the second period after the first period.

  The enable signal generators 3 and 4 generate enable signals b2 and b3 based on the reference signal.

  The level shifter 5 outputs a signal obtained by converting the signal b1 into a waveform level that can be turned ON / OFF between the source and drain of the transistor 7 as the signal b4 when the enable signal b2 is at a high level. The level shifter 5 makes the signal b4 low when the enable signal b2 is low. The level shifter 6 outputs a signal obtained by converting the signal b1 into a waveform level that can be turned ON / OFF between the source and drain of the transistor 8 as the signal b5 when the enable signal b3 is at a high level. The level shifter 6 makes the signal b5 high when the enable signal b3 is low.

  The transistors 7 and 8 are of the same type and have different conductivity types. In the present embodiment, field effect transistors (FETs) are applied as the transistors 7 and 8. Transistor 7 is P-type and transistor 8 is N-type. The drain terminals of the transistors 7 and 8 are both connected to one end of the ultrasonic transducer 11. Note that the other end of the ultrasonic transducer 11 is grounded. The source terminals of the transistors 7 and 8 are connected to the positive power source 9 or the negative power source 10 via the constant current source units 12 and 13. The gate terminals of the transistors 7 and 8 are connected to the output terminals of the level shifters 5 and 6.

  The positive power source 9 outputs positive power. The negative power supply 10 outputs negative power.

  The constant current source units 12 and 13 keep the current value output from the positive power source 9 or the negative power source 10 constant. The constant current source units 12 and 13 are configured using, for example, resistance elements.

  Next, the operation of the ultrasonic diagnostic apparatus configured as described above will be described.

  The transmission waveform generator 2 generates a signal b1 having a transmission waveform based on the reference signal. The signal b1 is a signal that becomes low level continuously or intermittently in the first period and becomes high level continuously or intermittently in the second period after the first period. In the first embodiment, as shown in FIG. 2, the signal b1 is intermittently at a high level in the period P11 of the first period P1, and intermittently in the period P21 of the second period P2. High level. Further, the signal b1 is at a low level during a period other than the period P11 in the first period P1, and is at a high level during a period other than the period P21 in the second period P2.

  The enable signal generator 3 sets the enable signal b2 to a high level only during the period P11. Therefore, the signal b4 output from the level shifter 5 is intermittently at a low level during the period P11 as shown in FIG. Note that here, the signal b4 is at a low level twice in the period P11 with one high level period in between.

  When the signal b4 is at a low level, the transistor 7 is turned on. Therefore, in the period P11, the transistor 7 is turned on twice with the one off state interposed therebetween. When the transistor 7 is in the ON state, power is supplied from the positive power source 9 to the ultrasonic transducer 11. At this time, since the constant current source unit 12 is connected to the source side of the transistor 7, the current supplied to the ultrasonic transducer 11 is adjusted to a constant value. Since the potential of the source terminal is determined by the gate voltage, if a resistance element is used as the constant current source unit 12, the current value output from the constant current source unit 12 is the potential difference between the positive power source 9 and the transistor 7. It is determined by the resistance value of the constant current source unit 12. In such a state, the potential of the drain terminal of the transistor 7 gradually increases. This is because the ultrasonic transducer 11 is a capacitive load.

  On the other hand, the enable signal generator 4 sets the enable signal b3 to a high level only during the period P21. Therefore, the signal b5 output from the level shifter 6 is intermittently at a low level during the period P11 as shown in FIG. Note that here, the signal b4 is at a low level twice in the period P11 with one high level period in between.

  When the signal b4 is at a low level, the transistor 8 is turned on. Accordingly, in the period P21, the transistor 8 is turned on twice with the one off state interposed therebetween. When the transistor 8 is in the ON state, power is supplied from the negative power source 10 to the ultrasonic transducer 11. Since the power supplied from the negative power source 10 is negative, current is sucked from the ultrasonic transducer 11 into the negative power source 10. At this time, since the constant current source unit 13 is connected to the source side of the transistor 8, the current drawn from the ultrasonic transducer 11 is adjusted to a constant value. Since the potential of the source terminal is determined by the gate voltage, if a resistance element is used as the constant current source unit 13, the current value output from the constant current source unit 13 is the potential difference between the negative power source 10 and the transistor 8 and It is determined by the resistance value of the constant current source unit 13. In such a state, the potential of the drain terminal of the transistor 8 gradually decreases.

  Note that when the transistors 7 and 8 are both OFF, the potentials of the drain terminals of the transistors 7 and 8 are maintained.

  As a result of the above, a signal b6 having a waveform having an inclination as shown in FIG. 2 is applied to the ultrasonic transducer 11. The rising and falling slopes of the signal b6 are determined by the current value output from the constant current source units 12 and 13 and the capacitive component of the ultrasonic transducer 11.

  Thus, according to the present embodiment, it is possible to reduce harmonic components included in the transmission waveform, and it is possible to improve transmission power efficiency.

(Second Embodiment)
FIG. 3 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 4 is a diagram showing signal waveforms and timing relationships at various parts in FIG. In FIG. 3, the same elements as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 3 shows only the configuration related to the transmission of ultrasonic waves. In recent years, an ultrasonic diagnostic apparatus generally includes a two-dimensional array or a three-dimensional array of multichannel transducers and displays a tomographic image in real time. For this reason, the transmitting unit also has a corresponding number of channels, but FIG. 3 shows only one of them.

  As shown in FIG. 3, the ultrasonic diagnostic apparatus according to the second embodiment includes an apparatus main body 101 and an ultrasonic probe 103. The ultrasonic probe 103 further includes level shifters 5 and 6, transistors 7 and 8, a positive power source 9, a negative power source 10, an ultrasonic transducer 11, constant current source units 12 and 13, and transmission waveform generators 21 and 22.

  The transmission waveform generators 21 and 22 generate signals c1 and c2 having the same waveform as the signals b4 and b5. The signals c1 and c2 generated by the transmission waveform generators 21 and 22 are input to the level shifters 5 and 6 in place of the signal b1.

  The level shifters 5 and 6 convert the waveform levels of the signals c1 and c2 to obtain signals b4 and b5. In the second embodiment, the level shifters 5 and 6 are always enabled.

  As described above, the ultrasonic diagnostic apparatus according to the second embodiment includes the transmission waveform generators 21 and 22 in place of the transmission waveform generator 2 and the enable signal generators 3 and 4 in the first embodiment. Then, the signal b6 similar to that of the first embodiment is applied to the ultrasonic transducer 11 as shown in FIG.

  Thus, also in the ultrasonic diagnostic apparatus of the second embodiment, it is possible to reduce harmonic components included in the transmission waveform, and to improve transmission power efficiency.

  This embodiment can be variously modified as follows.

  The number of pulses of the signals b4 and b5 and the time width of the pulses in the periods P11 and P21 can be changed as appropriate. By changing these, it is possible to adjust the smoothness of the slope of the waveform of the signal b6.

  The periods P11 and P12 can be arbitrarily set in the periods P1 and P2.

  At least a part of the functions of the transmission waveform generators 2, 21, 22, the enable signal generators 3, 4 and the level shifters 5, 6 may be provided on the apparatus main body 101 side.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components 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 constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The figure which shows the waveform and timing relationship of the signal of each part in FIG. The block diagram which shows the structure of the ultrasonic diagnosing device which concerns on the 2nd Embodiment of this invention. The figure which shows the waveform and timing relationship of the signal of each part in FIG. The figure which shows the conventional structural example of an ultrasound diagnosing device. The figure which shows the waveform and timing relationship of the signal of each part in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reference signal generator, 2, 21, 22 ... Transmission waveform generator, 3, 4 ... Enable signal generator, 5, 6 ... Level shifter, 7, 8 ... Transistor, 9 ... Positive power supply, 10 ... Negative power supply, 11 ... ultrasonic transducers, 12, 13 ... constant current source unit, 101 ... device main body, 102, 103 ... ultrasonic probe.

Claims (2)

In an ultrasonic diagnostic apparatus that diagnoses a subject using ultrasonic waves transmitted from an ultrasonic transducer,
First and second power supply means for outputting positive and negative constant currents, respectively;
First switch means for opening and closing a connection between the ultrasonic transducer and the first power supply means;
Second switch means for opening and closing a connection between the ultrasonic transducer and the second power supply means;
A first control means that closes the first switch means continuously or intermittently in a first period and opens continuously in a second period after the first period;
The second switch means includes a second control means that continuously opens during the first period and closes continuously or intermittently during the second period. Ultrasonic diagnostic equipment. An ultrasonic transducer,
First and second power supply means for respectively outputting positive and constant currents of opposite polarity;
First switch means for opening and closing a connection between the ultrasonic transducer and the first power supply means;
Second switch means for opening and closing a connection between the ultrasonic transducer and the second power supply means;
A first control means that closes the first switch means continuously or intermittently in a first period and opens continuously in a second period after the first period;
The second switch means includes a second control means that continuously opens during the first period and closes continuously or intermittently during the second period. Acoustic probe.

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