JP2005152450A - Ultrasonic observation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic observation apparatus which is capable of obtaining excellent ultrasonic images at a close point and a distant point from an ultrasonic vibrator by generating ultrasonic waves of arbitrary waveforms corresponding to a plurality of transmission modes. <P>SOLUTION: The ultrasonic observation apparatus comprises: an arbitrary waveform generation unit which includes an ultrasonic scan unit for mechanically rotating and moving back and forth the ultrasonic vibrator for scanning and transmits an ultrasonic signal of an arbitrary waveform from the ultrasonic vibrator; an ultrasonic amplifier 15 which amplifies the arbitrary waveform signal from the arbitrary waveform generation unit to a predetermined value and provides it to the ultrasonic vibrator; and a controller 16 which generates a bias for controlling the ultrasonic amplifier 15 into an active state and an inactive state in response to a synchronizing signal from the ultrasonic scan unit and controls the ultrasonic amplifier 15 to the inactive state simultaneously with the time when the arbitrary waveform signal is completely amplified out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ultrasonic diagnostic apparatus that transmits ultrasonic waves to a living tissue and receives a reflected ultrasonic wave from the living tissue to generate a tomographic image of the living tissue by using an ultrasonic reception signal generated. The present invention relates to an ultrasonic observation apparatus that transmits ultrasonic waves by controlling driving of a vibrator.

  In the medical field, an ultrasonic diagnostic apparatus that transmits ultrasonic waves to a living tissue and displays a tomographic image of the living tissue using a reflected ultrasonic signal reflected by the living tissue is used. As this ultrasonic diagnostic apparatus, an extracorporeal ultrasonic diagnostic apparatus that generates a tomographic image of a living tissue inside the body by contacting an ultrasonic probe with a built-in ultrasonic transducer on the surface of the body, inserted into the body cavity of the body An intracorporeal ultrasonic diagnostic apparatus (hereinafter referred to as an ultrasonic probe apparatus) that generates an tomographic image of an organ from within the body cavity by bringing an ultrasonic probe having a built-in ultrasonic transducer into contact with the organ wall in the body cavity. There is an ultrasonic endoscope apparatus in which an ultrasonic transducer is incorporated in an insertion portion having an observation optical system for observing the inside of a body cavity.

  Among such ultrasonic diagnostic apparatuses, the ultrasonic probe apparatus and the ultrasonic endoscope apparatus have an ultrasonic vibrator disposed at the distal end of an insertion portion to be inserted into a body cavity. Ultrasonic waves are transmitted within a predetermined range by mechanically rotating or moving back and forth, and imaging is performed using the reflected ultrasonic waves. Thereby, for example, the discovery and the degree of infiltration of a tumor which is a diseased part of an organ can be observed.

  The ultrasonic endoscope apparatus and the ultrasonic probe apparatus may shorten the distance between the ultrasonic transducer and the diseased part of the organ to be observed in order to insert the ultrasonic transducer into the body cavity. Is possible. As a result, the resolution of the ultrasonic tomographic image becomes good, and the diseased part can be examined closely. In order to make a diagnosis with good resolution, the ultrasonic wave transmitted from the ultrasonic transducer to the organ is compared with a general external ultrasonic diagnostic apparatus such as 7.5 MHz, 12 MHz, 20 MHz, etc. High frequencies are used.

  As described above, the distance between the ultrasonic transducer and the organ to be observed is shortened and the ultrasonic frequency is increased to improve the distance resolution of the ultrasonic tomographic image, and the ultrasonic frequency band. It is also done to widen.

  In order to generate ultrasonic waves of this high frequency and wide band, conventionally, rectangular pulses generated by a switching circuit formed using a field effect transistor (hereinafter simply referred to as FET) operated by a high voltage are used. The ultrasonic oscillation is controlled by supplying the ultrasonic transducer.

  Further, the ultrasonic probe apparatus and the ultrasonic endoscope apparatus are required not only to improve the resolution in the distance direction but also to improve the resolution in the azimuth direction. In recent years, tissue harmonic imaging (hereinafter referred to as THI) has been used to improve the resolution in the azimuth direction.

  The principle of this THI is that the irradiated ultrasonic waves are distorted by the living tissue and generate harmonics. When only the harmonics are extracted and converted into an image, an image with improved azimuth resolution is obtained. This harmonic beam shape is known to be sharper and narrower than the fundamental beam shape, and THI is realized by extracting the harmonic.

  Furthermore, in ultrasound diagnosis from inside the body cavity, it is possible to observe not only the close examination of the ultrasonic transducer and the observation organ but also the ultrasonic tomographic image at a far point where the ultrasonic wave reaches far from the ultrasonic transducer. There is a strong demand. The reason for this is to diagnose a large lesion and confirm the position of the ultrasonic transducer relative to the organ in the blind insertion operation. In other words, there is a case where it is difficult to determine where the ultrasonic wave is being scanned in the body cavity when performing the radiation scan of the ultrasonic wave from the body cavity. Accordingly, it is necessary for the operator to be able to recognize the position of the currently observed observation site image by obtaining an ultrasonic tomographic image of an organ around the ultrasonic observation site.

  Various means such as broadband transmission and pulse compression are used as means for improving the deep speed in response to this demand. With broadband transmission, an ultrasonic transducer having a wider frequency band than that of a conventional ultrasonic transducer is used, and a transmission wave having a wider frequency band is generated and transmitted. The wideband frequency ultrasonic waves transmitted by this wideband transmission also become a signal having a wide frequency band as a reception signal which is a reflected ultrasonic wave from a living tissue. Using this received signal with a wide frequency band, a near point that is close to the ultrasonic transducer generates a high-frequency ultrasonic tomogram, and a far point that is far from the ultrasonic transducer is a low frequency. Only an ultrasonic tomogram is generated and displayed on the monitor. As a result, when viewed from the ultrasonic transducer, the shallow portion, which is the living tissue at the near point, is an ultrasonic tomographic image with good resolution, and the deep portion, which is the far point, when viewed from the ultrasonic transducer, is a sensitive ultrasonic tomographic image. Can be displayed on the monitor.

  The pulse compression includes two methods, a method using a chirp wave and a method using a coded pulse. In pulse compression using a chirp wave, an ultrasonic wave having a transmission waveform in which the frequency is swept from a low frequency to a high frequency is generated and transmitted. Alternatively, an ultrasonic wave having a transmission waveform in which the frequency is swept from a high frequency to a low frequency is generated and transmitted. At the time of reception of reflected ultrasonic waves in which the transmission waveform with the frequency swept is reflected from the living tissue, a reference wave that is substantially equivalent to the transmission waveform is prepared, and correlation processing is performed between the reference wave and the reception signal. A so-called convolution operation process is performed. This convolution calculation process has the advantage of improving the depth speed because it is temporally compressed to improve resolution and S / N. However, it also has the disadvantage that side lobes remain.

  Furthermore, pulse compression using coded pulses is Golay code or the like as a coding method, but the processing method is equivalent to the above chirp wave, and in the same way, the depth of penetration can be improved, The problem of the occurrence of side lobes arises.

As described above, Patent Document 1 proposes an ultrasonic transmission circuit for generating and supplying an ultrasonic oscillation signal to be supplied to an ultrasonic transducer in accordance with an ultrasonic transmission method for scanning an observation target region.
JP 2000-152930 A

  An ultrasonic endoscope device or an ultrasonic probe device inserts an insertion portion having a built-in ultrasonic transducer into a body cavity, transmits ultrasonic waves from the ultrasonic transducer to an organ in the body cavity, and An ultrasonic tomographic image of an organ is generated and displayed by a reception signal that is a reflected ultrasonic wave, and a diseased part of the organ is observed from the ultrasonic tomographic image.

  As described above, the ultrasonic wave transmitted to the organ in the body cavity by this ultrasonic endoscope apparatus or ultrasonic probe apparatus is combined with the short pulse transmission mode and the pulse according to the organ to be observed and the observation purpose. Transmission that controls driving of an ultrasonic transducer according to multiple transmission modes such as a wideband transmission mode, a transmission mode using only a fundamental wave using THI, a pulse compression mode using a chirp wave, and a pulse compression mode using a coded pulse. A circuit is used.

  In response to the request to drive the ultrasonic transducer according to the plurality of transmission modes, in the transmission circuit as proposed in Patent Document 1, a high voltage switch using a switching circuit constituted by an FET is used. In control, it is difficult to respond. For example, in the transmission mode of only the fundamental wave required in THI, if the transmission circuit is compatible with the short pulse transmission mode, harmonics are also transmitted and THI cannot be realized. In this short pulse transmission mode, in order to obtain THI, it is necessary to perform control to transmit ultrasonic waves twice to the same observation site. However, the ultrasonic vibration built in the distal end of the insertion portion is mechanically rotated, or It is not suitable for mechanical scanning in which the ultrasound is scanned by moving back and forth. Further, the pulse compression mode by the chirp wave cannot be realized by the switching of the FET, and a power amplifier is required separately from the switching circuit by the FET.

  As means for solving such a problem, there is means for replacing the high voltage FET switching circuit with a power amplifier. However, when replaced with a power amplifier, the power consumption is enormous, and in the case of mechanical scanning of an ultrasonic transducer, a 100 W class amplifier is necessary, which is difficult to realize.

  In addition, when this power amplifier is mounted, the influence of noise on the received signal is great. In particular, in order to handle signals that are significantly different in time from pulse waves and chirp waves, taking into account long time chirp waves and taking measures to prevent noise from being mixed in during the reception period, noise will appear in the pulse wave and will be completely removed. There is a problem that noise cannot be removed.

  In view of the above circumstances, the present invention can generate an arbitrary high voltage waveform such as a short pulse, THI, or chirp wave, suppresses noise during the reception period of reflected ultrasonic waves, and reduces S / N. In addition to providing an ultrasonic transmission circuit capable of obtaining a good ultrasonic image, when switching the ultrasonic output waveform from the ultrasonic transducer, there is no significant difference in sensitivity of the ultrasonic image, and an arbitrary transmission mode can be selected according to the transmission mode. It is an object of the present invention to provide an ultrasonic transmission circuit capable of controlling the amplitude value of the output waveform to the ultrasonic transducer in conjunction with the waveform.

  The ultrasonic observation apparatus of the present invention is an ultrasonic observation apparatus having an ultrasonic transducer having at least one transducer and an ultrasonic scanning unit that mechanically rotates or advances and retracts the ultrasonic transducer. An arbitrary waveform generator for generating an arbitrary waveform signal for oscillating and transmitting an ultrasonic signal of an arbitrary waveform from the ultrasonic transducer, and amplifying the arbitrary waveform signal from the arbitrary waveform generator to a predetermined value, The ultrasonic amplifying unit is supplied to the ultrasonic transducer, and the ultrasonic amplifying unit is activated and deactivated by a synchronization signal synchronized with the mechanical rotation or advance / retreat operation of the ultrasonic transducer from the ultrasonic scanning unit. After a certain period of time has elapsed since the start of the operation state, the arbitrary waveform signal from the arbitrary waveform generation unit is input and amplified, and at the same time as the amplification output of the arbitrary waveform signal ends, the ultrasonic amplification unit is put into a non-operation state Gosuru is characterized by comprising a controller.

  The ultrasonic amplification unit of the ultrasonic observation apparatus of the present invention is characterized in that the amplification degree can be switched in accordance with an arbitrary waveform signal from the arbitrary waveform generation unit.

  The arbitrary waveform generator of the ultrasonic observation apparatus of the present invention is capable of sequentially switching the arbitrary waveform signal supplied to the ultrasonic amplifying unit in synchronization with the synchronization signal from the ultrasonic scanning unit. It is said.

  The controller of the ultrasonic observation apparatus of the present invention controls the driving state of the arbitrary waveform generation unit and the ultrasonic amplification unit based on the input information from the ultrasonic transducer, the display form of the ultrasonic tomographic image, and the console. It is characterized by making it possible.

  With the ultrasonic observation apparatus of the present invention, it is possible to generate and transmit an ultrasonic wave having an arbitrary waveform according to the transmission mode of the ultrasonic wave transmitted from the ultrasonic transducer, and to reduce the power consumption of the power amplifier. An ultrasonic image with a good S / N can be obtained at both the point and the far point.

  The ultrasonic observation apparatus of the present invention can generate an ultrasonic output of an arbitrary transmission waveform corresponding to a plurality of ultrasonic transmission modes, and arbitrarily enables the power amplifier according to the duration of the transmission waveform of the transmission mode. Can be controlled, and an ultrasonic image with a good S / N of the observation site at the near point of the ultrasonic transducer can be obtained. Furthermore, the power amplifier enable period can be optimally controlled by adapting to an arbitrary transmission waveform according to the ultrasonic transmission mode, so that power consumption can be minimized and the power amplifier can be miniaturized. became.

  Therefore, a miniaturized power amplifier that consumes the least amount of power can be realized, and it has an effect of being able to observe an ultrasonic image with excellent resolution from a shallow part to a deep part of an observation site and a high depth speed.

  Hereinafter, an ultrasonic transmission circuit according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of an ultrasonic transmission circuit in an ultrasonic observation apparatus according to the present invention, and FIG. 2 is a connection diagram showing the configuration of a power amplifier used in the ultrasonic transmission circuit in the ultrasonic observation apparatus according to the present invention. FIG. 3 is a connection diagram showing configurations of a variable amplifier and a power amplifier used in an ultrasonic transmission circuit in the ultrasonic observation apparatus according to the present invention. FIG. 4 is a diagram illustrating driving of an ultrasonic transducer by the ultrasonic transmission circuit according to the present invention. FIG. 5 is a timing chart for explaining the drive control operation of the ultrasonic transducer in various modes of the ultrasonic transmission circuit according to the present invention. FIG. 6 is a timing chart for explaining the control operation by the ultrasonic transmission circuit according to the present invention. FIG. 7 is an explanatory diagram for explaining a monitor display state of an ultrasonic tomogram generated from a short pulse transmission transmitted from an acoustic transducer and an ultrasonic reception signal by burst transmission. A short pulse transmissions have been transmitted from the ultrasonic transducer by ultrasonic transmission circuit according an explanatory view for explaining an ultrasonic tomographic image each monitor display state generated from the received signal of the ultrasonic waves by burst transmission.

  First, the overall configuration of the ultrasonic transmission circuit in the ultrasonic observation apparatus according to the present invention will be described with reference to FIG. The ultrasonic transmission circuit includes a waveform memory 11, a shift register 12, a digital / analog converter (hereinafter simply referred to as a D / A converter) 13, a variable amplifier 14, a power amplifier 15, and a controller 16. .

  The waveform memory 11 is a memory that stores transmission ultrasonic waveform data in a plurality of transmission modes described above as digital data. The shift register 12 reads predetermined digital data from the waveform memory 11 and outputs it to the D / A converter 13. The D / A converter 13 converts the digital data supplied from the shift register 13, for example, 8-bit digital data into an analog signal and supplies the analog signal to the variable amplifier 14. The variable amplifier 14 amplifies the analog signal supplied from the D / A converter 13 with a predetermined amplification degree, and supplies the amplified signal to the power amplifier 15. The power amplifier 15 amplifies the amplified analog signal supplied from the variable amplifier 14 by approximately 50 db and outputs the amplified analog signal to an ultrasonic transducer (not shown). The controller 16 controls driving of the waveform memory 11, the shift register 12, the variable amplifier 14, and the power amplifier 15.

  The waveform memory 11, the shift register 12, and the D / A converter 13 constitute an arbitrary waveform generator for transmitting ultrasonic waves according to the plurality of transmission modes described above.

  The controller 16 includes a mechanical rotation or advancing / retreating of an ultrasonic transducer at the distal end of an insertion portion of an ultrasonic endoscope (not shown) or an ultrasonic transducer provided at a probe distal end of an ultrasonic probe device. A phase signal, which is a synchronization signal synchronized with scanning, and a frequency code indicating identification of the ultrasonic endoscope apparatus or ultrasonic probe apparatus are input. Furthermore, a frequency code signal indicating the identification of the ultrasonic endoscope apparatus or ultrasonic probe apparatus used by the operator and other instruction information for controlling the driving of the ultrasonic transmission circuit are received from a console (not shown). It can be input.

  The controller 16 sets the address of waveform data to be read from the waveform memory 11 based on the input A-phase signal and frequency code signal, generates waveform data read clock from the waveform memory 11 by the shift register 12, and the variable amplifier. A gain control signal for setting an amplification factor of 14 and a V_Gate signal for controlling an enable period for receiving an analog signal supplied from the variable amplifier 14 of the power amplifier 15 are generated.

The timing of various control signals generated in the controller 16 of this ultrasonic transmission circuit will be described with reference to FIG.
An A-phase signal from an ultrasonic operation unit that performs mechanical rotation of an ultrasonic transducer of an ultrasonic endoscope apparatus and an ultrasonic probe apparatus (not shown) or scans back and forth is output, for example, 256 pulses per rotation. Assuming that the ultrasonic transducer is rotating at 6.67 rps, the pulse interval of the A phase is pulse interval = 1 / 6.67 / 256/2 = 293 μs. That is, an ultrasonic transmission signal is output from the ultrasonic transmission circuit to the ultrasonic transducer once every 293 μs, and the ultrasonic wave is oscillated and transmitted.

  The clock signal shown in FIG. 4 is a clock for controlling the driving of the controller 16 of the ultrasonic transmission circuit, and the generation output of the address signal, gain control signal, V_Gate signal, etc. is controlled in synchronization with this clock signal. Done.

  The controller 16 raises the delay gate signal in synchronization with the rising and falling edges of the A phase signal. The delay gate signal is controlled so as to fall from the rising edge by counting a predetermined value of the clock signal by a counter (not shown). For example, the delay gate signal width is set to 3 μs in the example of the embodiment of the present invention so that only the time required for a power amplifier 15 to be described later is counted.

  Next, the bias gate signal rises during the operation of a read clock signal described later after the delay gate signal falls. The delay gate signal and the bias gate signal control the enable of the power amplifier 15 described later. The read clock signal is controlled by a frequency code input to the controller 16 for identifying the input ultrasonic endoscope apparatus or ultrasonic probe apparatus and an identification frequency code input from the console. At the same time, the number of clocks of the read clock signal is controlled by the duration of the ultrasonic signal output from the ultrasonic transducer.

  The V_Gate signal has a pulse width b obtained by adding the delay gate signal and the bias gate, and becomes high (HIGH) after the A-phase signal is input until the read clock signal ends. That is, the power amplifier 15 of the ultrasonic transmission circuit is enabled during the high period of the V_Gate signal, and is disabled during the low (LOW) period.

  The Tx trigger signal is generated and output in synchronization with the delay gate signal. This Tx trigger signal controls the timing of capturing data when receiving a reflected ultrasonic signal (not shown).

  The Tx signal is obtained by converting the arbitrary waveform data corresponding to the transmission mode read from the waveform memory 11 by the shift register 12 from the digital data to the analog signal in the D / A converter 13 under the control by the read clock signal. It is an arbitrary waveform signal converted into. The Tx signal is amplified by the variable amplifier 14, is amplified when the power amplifier 15 is enabled, is converted to a voltage of about 100 Vp-p, and is output to the ultrasonic transducer.

  Next, the configuration of the power amplifier 15 of the ultrasonic transmission circuit will be described with reference to FIG. The Tx signal supplied from the variable amplifier 14 is input to the input terminal Vin. The input terminal Vin is connected to the ground potential via the resistor R1, and is also connected to the ground potential via a series connection of the capacitor C2, the primary side of the impedance matching unit T1, and the capacitor C1.

  One end of the secondary side of the impedance matching unit T1 is connected to the ground potential via the resistor R2, and one of the gates of the differential FETQ1 having the sources connected to each other, the resistor R4, and the capacitor C3. It is connected to one drain of the FET Q1 through a series connection. The other end of the secondary side of the impedance matching unit T1 is connected to a ground potential via a resistor R3, and the other end of the FET Q1 is connected to the other gate of the FET Q1 via a series connection of a resistor R7 and a capacitor C4. Connected to the drain. A resistor R5 and a resistor R6 are connected in series between both gates of the FET Q1, and a V_Gate terminal to which the V_Gate signal is supplied is connected to a connection point between the resistors R5 and R6.

  Between both drains of the FET Q1, a transformer T2 that distributes and supplies drive power from the drive power supply Vcc is connected to each drain. A driving power source Vcc is connected to an intermediate point of the transformer T2, and is connected to a ground potential via a capacitor C5. Further, one drain of the FET Q1 is connected to the ground potential through a series connection of one side of the synthesis transformer T3 and the capacitor C6, and the other drain of the FET Q1 is connected to the other side of the synthesis transformer T3 and the capacitor C7. Are connected to the phase distributor T4 through a series connection.

  That is, the FET Q1, resistors R2, R3, R4, R, R6, R7, capacitors C3, C4, and transformer T2 constitute an amplification stage 15a. The Tx signal supplied from the input terminal Vin is impedance-matched in the impedance matching unit T1, and Tx is different in phase by 180 ° from the secondary side of the impedance matching unit T1 to each gate of the FET Q1 of the amplification stage 15a. A signal is input.

  The FET Q1 operates by supplying a current to the resistors R5 and R6 by the V_Gate signal supplied from the V_Gate terminal, and applying the gate voltage of the FET Q1 by the currents of the resistors R5 and R6. That is, when the V_Gate signal is low (0 V), no current flows through the resistors R5 and R2 and the resistors R6 and R3, the gate potential becomes 0 V, and the FET Q1 does not operate. If the FET Q1 does not operate, no current is supplied to the FET Q1 from the drive power supply Vcc, so that the amplification operation in the FET Q1 is not performed and no current is consumed.

  Further, when the V_Gate signal at the V_Gate terminal is high, a gate voltage is applied to the FET Q1, current is supplied from the driving power source Vcc, and the FET Q1 performs an amplification operation, and the 180 ° phase from the impedance matching unit T1. Each different Tx signal is amplified. In the embodiment of the present invention, the amplification stage 15a is set to obtain a gain of about 50 db.

  The Tx signals different in phase by 180 ° amplified by the FET Q1 of the amplification stage 15a are synthesized by the synthesis transformer T3 connected to the respective drains of the FET Q1. The synthesized Tx signal generates Tx signals having a phase difference of 180 ° in the phase distributor T4.

  Both output terminals of the phase distributor T4 are connected to the ground potential via the primary sides of the impedance matching units T5 and T6. On the secondary side of the impedance matching unit T5, an amplification stage 15b having the same configuration as that of the amplification stage 15a is provided with the FET Q2 as a main component. On the secondary side of the impedance matching unit T6, an amplification stage 15c having the same configuration as that of the amplification stage 15a is provided mainly with the FET Q3.

  The Tx signal input to the impedance matching unit T5 of the amplification stage 15b is output as a Tx signal having a phase difference of 180 ° from the secondary side, and the resistors R13 and R8 and the resistor R14 are received by the V_Gate signal supplied from the V_Gate terminal. , R9, a bias current flows, and when a voltage is applied to the gate of FET Q2, the operating point of FET Q2 is set. When this operating point is set, a drive current is supplied to the FET Q2 from the drive power supply Vcc via the transformer T7, and the Tx signal supplied to the respective gates of the FET Q2 is amplified to a signal having a predetermined magnitude.

  The Tx signal input to the impedance matching unit T6 of the amplification stage 15c is amplified by the FET Q3 by the same operation as that of the amplification stage 15b. The difference between the amplification stages 15b and 15c is only that the phases of the Tx signals supplied to the impedance matching units T5 and T6 are different.

  That is, the amplification stages 15b and 15c perform the amplification operation by supplying the drive power supply Vcc from the V_Gate terminal only during the high period of the V_Gate signal, as in the above-described amplification stage 15a, and the V_Gate signal is driven during the low period. Is not applied and no amplification operation is performed. For this reason, when the FETQ2 and FETQ3 are not operating, the power consumption can be made almost zero.

  In the FET Q2 of the amplification stage 15b, the amplified Tx signals having different phases are synthesized by the synthesis transformer T9 and output to the phase distribution adder T11 described later. In the FET Q3 of the amplification stage 15c, the amplified Tx signals having different phases are synthesized by the synthesis transformer T10 and output to the phase distribution adder T11 described later. The phase distribution adder T11 performs phase distribution combination processing on the Tx signals having different phases from the synthesis transformer T9 of the amplification stage 15b and the synthesis transformer T10 of the amplification stage 15c, and outputs the output terminal Vout via the resistor R20. To an ultrasonic transducer (not shown).

  By using such a power amplifier 15 in the ultrasonic transmission circuit, it is possible to generate an oscillation control signal of an ultrasonic transducer having an arbitrary waveform. Further, by setting the gate bias of the FETs Q1, Q2, and Q3 by the V_Gate signal, it is possible to amplify and output the oscillation control signal of the ultrasonic transducer having an arbitrary waveform during the enable period due to the gate bias. Further, during the disable state, the amplification operation of the oscillation control signal of the ultrasonic transducer is stopped, and the output of the oscillation control signal of the ultrasonic transducer is also stopped.

  Accordingly, when the enable state and the disable state of the power amplifier 15 are compared, assuming that the period of the enable state is 0.5 μs, the repetition period of the A phase is 293 μs, so the duty cycle is 0.177%. Become. Therefore, when the maximum output wattage of the power amplifier 15 is 100 W, the duty cycle is 0.177% and the average power is 17.7 W, and the power amplifier 15 can be downsized. Furthermore, the power amplifier 15 operates only during the enable period, which is the generation period of the oscillation control signal of the ultrasonic transducer, and is set to the de-enable period immediately after the transmission of the oscillation control signal of the ultrasonic transducer in this enable period. Therefore, almost no noise is generated, and the S / N improvement of the ultrasonic image is possible.

  Next, the variable amplifier 14 of the ultrasonic transmission circuit will be described with reference to FIG. The variable amplifier 14 is indicated by a symbol U1 in the figure, and the D / A converter 13 amplifies the Tx signal converted into an analog signal into a signal of an arbitrary amplification degree, and the amplified signal is The power is supplied to the power amplifier 15. The control of the amplification degree is set by a gain control signal from the controller 16.

  By providing the variable amplifier 15, when the sensitivity of the ultrasonic image changes without complicating the power amplifier 15 and by an arbitrary waveform of the ultrasonic wave transmitted from the ultrasonic transducer, for example, from the console. Control that makes the display brightness of the ultrasonic image constant by a gain control signal from the controller 16 input by the operator is also possible.

  Next, the operation timing in various transmission modes of the ultrasonic transmission circuit of the present invention will be described with reference to FIG. As shown in FIG. 5A, the conventional ultrasonic transmission circuit receives reflected ultrasonic waves in synchronization with the rise and fall of the A-phase signal synchronized with the rotation of the ultrasonic transducer or the advance / retreat scanning. The Tx trigger signal for the reception timing of the received signal data in the ultrasonic receiving unit and the Tx data signal for driving the ultrasonic transducer in the ultrasonic transmission circuit are generated. For this reason, since the power amplifier continues to operate even after the transmission of the Tx data signal is completed, it is affected by noise and the average current consumption of the power amplifier is also increased.

  On the other hand, as shown in FIG. 5B, the ultrasonic transmission circuit of the present invention is set by the short pulse transmission mode from the controller 16 when the ultrasonic transducer is controlled to be oscillated by a short pulse. The V_Gate signal is set to the high period a. During the high period a of the V_Gate signal, the power amplifier 15 is in an operating state. The Tx trigger signal is raised after a predetermined time d has elapsed from the rise of the V_Gate signal, and the Tx signal for driving the oscillation of the ultrasonic transducer is transmitted. During the low period of the V_Gate signal, the power amplifier 15 is in an inoperative state, and transmission of the Tx signal for driving the oscillation of the ultrasonic vibrator is also stopped, so that generation of noise can be prevented. As a result, the S / N of the ultrasonic image of the observation site near the ultrasonic transducer is also improved. For example, as shown in FIG. 7A, in the 4 cm range, when a short pulse is generated in order to observe the shallow part of the subject with high resolution, the V_Gate signal is set to the period a in FIG. Therefore, it is possible to observe an ultrasonic image with a good S / N at a point near the ultrasonic transducer.

  Next, as shown in FIG. 5 (c), the ultrasonic transmission circuit of the present invention uses the V_Gate set by the chirp wave transmission mode from the controller 16 when controlling the oscillation of the ultrasonic transducer by the chirp wave. The signal is set to the high period b. During the high period b of the V_Gate signal, the power amplifier 15 is in an operating state. The Tx trigger signal is raised after a predetermined time d has elapsed from the rise of the V_Gate signal, and the Tx signal for driving the oscillation of the ultrasonic transducer is transmitted.

  In other words, the high period b of the V_Gate signal is varied in accordance with the length of the chirp wave transmission data of the ultrasonic vibrator, and the operation state period of the power amplifier is controlled to thereby drive and oscillate the ultrasonic vibrator. The necessary data can be transmitted, and the power amplifier 15 is brought into a non-operating state immediately after the high period of the V_Gate signal ends. As a result, the generation of noise can be prevented, and the S / N of the ultrasonic image near the ultrasonic transducer is also improved. For example, as shown in FIG. 7B, in the 9 cm range, when a chirp wave or burst wave is generated in order to observe the deep part of the subject, the V_Gate signal is as shown in FIG. Since it is supplied in the period b, the duration of the Tx signal becomes longer. As a result, it is possible to observe an ultrasonic image with a good S / N of an observation site near the ultrasonic transducer. As described above, since the length of the high period of the V_Gate signal can be linked according to the transmission mode of the ultrasonic transducer and according to the length of the drive data, the S / N is always good. Observation of an ultrasonic tomogram.

  Combining the oscillation control by the short pulse and the oscillation control by the chirp wave, as shown in FIG. 5 (d), for each sound ray of the oscillation drive control of the ultrasonic transducer, the short pulse and the chirp wave It is also possible to alternately switch transmission with burst transmission such as. As a result, by synthesizing the image by the burst transmission with the image by the short pulse, as shown in FIG. 6, the ultrasonic image of the shallow part of the observation site that is the near point from the ultrasonic transducer by the short pulse has a resolution. The ultrasonic image of the deep part of the observation site, which is the far point of the ultrasonic transducer by burst transmission, has a good depth of penetration.

  Note that when such short pulse transmission and burst transmission such as a chirp wave are switched and transmitted for each sound ray, the transmission sound pressure is different, so that the luminance may be discontinuous when the ultrasonic image is synthesized. As a method of solving this luminance discontinuity, there is a method of controlling the maximum amplitude of the Tx signal.

  The control of the maximum amplitude of the Tx signal controls the amplification degree of the variable amplifier 14 according to the length of the high period a of the short pulse of the V_Gate signal and the length of the high period b of the chirp wave. By controlling the amplification degree of the variable amplifier 14 according to the length of the high period of the V_Gate signal, the synthesized and generated ultrasonic image has a good resolution from near point to far point and has a depth of penetration. It is possible to provide an image with good S / N.

  As described above, the ultrasonic observation apparatus of the present invention can generate an ultrasonic output of an arbitrary transmission waveform corresponding to a plurality of ultrasonic transmission modes, and can be arbitrarily selected according to the duration of the transmission waveform of the transmission mode. In addition, it is possible to control the enable state of the power amplifier, and an ultrasonic image with a good S / N of the observation site near the ultrasonic transducer can be obtained. Furthermore, the power amplifier enable period can be optimally controlled by adapting to an arbitrary transmission waveform according to the ultrasonic transmission mode, so that power consumption can be minimized and the power amplifier can be miniaturized. became.

  Therefore, a miniaturized power amplifier that consumes the least amount of power can be realized, and observation can be performed with an ultrasonic image having excellent resolution from a shallow part to a deep part of the observation site and a high depth speed.

[Appendix]
According to the embodiment of the present invention described in detail above, the following configuration can be obtained.

(Appendix 1)
In an ultrasonic observation apparatus having an ultrasonic transducer having at least one transducer and an ultrasonic scanning unit that mechanically rotates or advances and retracts the ultrasonic transducer,
An arbitrary waveform generator for generating an arbitrary waveform signal for oscillating and transmitting an ultrasonic signal of an arbitrary waveform from the ultrasonic transducer;
Amplifying the arbitrary waveform signal from the arbitrary waveform generator to a predetermined value, and supplying the ultrasonic transducer to the ultrasonic transducer; and
The ultrasonic amplifying unit is controlled to an operating state and a non-operating state by a synchronization signal synchronized with mechanical rotation of the ultrasonic transducer from the ultrasonic scanning unit or advancing / retreating operation, and after a certain period of time has elapsed since the start of the operating state A controller that inputs and amplifies an arbitrary waveform signal from the arbitrary waveform generator, and controls the ultrasonic amplifier to a non-operation state simultaneously with completion of amplification output of the arbitrary waveform signal;
An ultrasonic observation apparatus comprising:

  (Supplementary note 2) The ultrasonic observation apparatus according to supplementary note 1, wherein the ultrasonic amplification unit is capable of switching an amplification degree in accordance with an arbitrary waveform signal from the arbitrary waveform generation unit.

  (Additional remark 3) The arbitrary waveform signal supplied to the said ultrasonic amplification part can be sequentially switched from the said arbitrary waveform generation part synchronizing with the synchronizing signal from the said ultrasonic scanning part, The additional remark 1 characterized by the above-mentioned. The described ultrasonic observation apparatus.

  (Additional remark 4) The said controller enables control of the drive state of the said arbitrary waveform generation part and the said ultrasonic amplification part by the input information from the said ultrasonic transducer | vibrator, the display form of an ultrasonic tomographic image, and a console. The ultrasonic observation apparatus according to any one of appendices 1 to 3, characterized by:

  (Additional remark 5) Any of the additional remarks 1 thru | or 4 by which the said ultrasonic amplification part is comprised with a field effect transistor, and controls an operation state and a non-operation state by supply of the bias voltage of this field effect transistor. The ultrasonic observation apparatus according to the above.

(Appendix 6)
In an ultrasonic observation apparatus having an ultrasonic transducer having a single or a plurality of transducers and an ultrasonic operation unit that mechanically rotates or advances and retracts the ultrasonic transducers,
A bias applying means for applying a bias voltage to the FET of the ultrasonic amplifier circuit for applying an electric pulse to the ultrasonic transducer by a synchronization signal from the ultrasonic operating section; and a bias voltage applied to the bias applying means at the time of application. An arbitrary waveform generator capable of inputting an arbitrary waveform to the ultrasonic amplifier circuit after a certain period from the synchronization signal;
A controller for stopping the bias applying means at the same time after amplifying and outputting an arbitrary waveform from the ultrasonic amplifier circuit;
An ultrasonic transmission circuit comprising:

  (Additional remark 7) The said ultrasonic transmission circuit switches amplification degree according to the output of the said arbitrary waveform generator, The ultrasonic transmission circuit of Additional remark 6 characterized by the above-mentioned.

  (Supplementary note 8) The ultrasonic transmission circuit according to supplementary note 6, wherein the ultrasonic transmission circuit sequentially switches an arbitrary waveform from an arbitrary waveform generation unit in synchronization with a synchronization signal.

  (Supplementary note 9) The output signal from the arbitrary waveform generator is switched between a pulse waveform and a burst wave in accordance with signals from an ultrasonic transducer, a display lens, and a console. Sonic transmission circuit.

The block diagram which shows the whole structure of the ultrasonic transmission circuit in the ultrasonic observation apparatus which concerns on this invention. The connection diagram which shows the structure of the power amplifier used for the ultrasonic transmission circuit in the ultrasonic observation apparatus which concerns on this invention. The connection diagram which shows the structure of the variable amplifier and power amplifier which are used for the ultrasonic transmission circuit in the ultrasonic observation apparatus which concerns on this invention. 4 is a timing chart for explaining the drive control operation of the ultrasonic transducer by the ultrasonic transmission circuit according to the present invention. 4 is a timing chart for explaining the drive control operation of the ultrasonic transducer in various modes of the ultrasonic transmission circuit according to the present invention. Explanatory drawing explaining the monitor display state of the ultrasonic tomogram produced | generated from the short pulse transmission transmitted from the ultrasonic transducer by the ultrasonic transmission circuit which concerns on this invention, and the ultrasonic reception signal by burst transmission. Explanatory drawing explaining the monitor display state of each of the ultrasonic tomogram produced | generated from the short pulse transmission transmitted from the ultrasonic transducer by the ultrasonic transmission circuit which concerns on this invention, and the ultrasonic reception signal by burst transmission.

Explanation of symbols

11 Waveform Memory 12 Shift Register 13 Digital / Analog Converter (D / A Converter)
14 Variable amplifier 15 Power amplifier 16 Controller Agent Patent attorney Susumu Ito

Claims (4)

In an ultrasonic observation apparatus having an ultrasonic transducer having at least one transducer and an ultrasonic scanning unit that mechanically rotates or advances and retracts the ultrasonic transducer,
An arbitrary waveform generator for generating an arbitrary waveform signal for oscillating and transmitting an ultrasonic signal of an arbitrary waveform from the ultrasonic transducer;
Amplifying the arbitrary waveform signal from the arbitrary waveform generator to a predetermined value, and supplying the ultrasonic transducer to the ultrasonic transducer; and
The ultrasonic amplifying unit is controlled to be in an operating state and a non-operating state by a synchronization signal synchronized with mechanical rotation of the ultrasonic transducer from the ultrasonic scanning unit or advancing / retreating operation, and after a certain period of time has elapsed since the start of the operating state. A controller that inputs and amplifies an arbitrary waveform signal from the arbitrary waveform generator, and controls the ultrasonic amplifier to a non-operation state simultaneously with completion of amplification output of the arbitrary waveform signal;
An ultrasonic observation apparatus comprising:   The ultrasonic observation apparatus according to claim 1, wherein the ultrasonic amplification unit is capable of switching an amplification degree in accordance with an arbitrary waveform signal from the arbitrary waveform generation unit.   2. The super-waveform according to claim 1, wherein the arbitrary waveform signal supplied to the ultrasonic amplifying unit can be sequentially switched from the arbitrary waveform generating unit in synchronization with a synchronization signal from the ultrasonic scanning unit. Sound observation device.   The controller is capable of controlling the driving state of the arbitrary waveform generation unit and the ultrasonic amplification unit according to input information from the ultrasonic transducer, a display form of an ultrasonic tomographic image, and a console. The ultrasonic observation apparatus according to claim 1.

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