JP3209545B2 - Ultrasonic drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic driving apparatus used for medical ultrasonic treatment for emulsifying and crushing unnecessary tissue.

[0002]

2. Description of the Related Art Ultrasonic treatment concentrates ultrasonic energy on unnecessary tissues and bones, and is effective in emulsifying, crushing, aspirating and cutting bones of unnecessary tissues, and selectively treating tumors and calculi. It is used in a wide range of medical surgery fields.

In an apparatus for performing such ultrasonic treatment and treatment, an ultrasonic transducer is provided in a hand-held handpiece.

This handpiece has a configuration in which the ultrasonic vibration of the ultrasonic vibrator is amplified by a horn and transmitted to a probe at the tip.

Conventionally, as a driving device of this type of device, there is one disclosed in US Pat. No. 4,827,911 and US Pat. No. 4,587,958 (JP58-58034A).

US Pat. No. 4,827,911 discloses an ultrasonic surgical device including a suction device. This has two setting values, high and low, for the vibration amplitude of the ultrasonic transducer.
By repeating the vibration amplitude at high and low levels and controlling the ratio of high and low, it is possible to adjust the temperature of the tissue to be crushed.

US Pat. No. 4,587,958 (JP58-58034A) also discloses an ultrasonic surgical apparatus, in which a technique for suppressing an inrush current generated at the start of ultrasonic vibration is disclosed. Thereby, the shock at the start of the vibration can be reduced, and the ultrasonic vibrator and the driving device can be protected.

[0008]

However, in US Pat. No. 4,827,911, the switching of the vibration amplitude between high and low is abrupt, and the mechanical vibration of the probe becomes inertial and adds to the vibration of the ultrasonic vibrator. There is a problem of giving a shock to the vibrator.

For example, as shown in FIG. 12, when the vibration amplitude changes from a low level to a high state, a large overshoot occurs in the vibration amplitude due to inertia. Conversely, the same applies when changing from a high vibration amplitude to a low vibration amplitude,
The amplitude value at the change point becomes unstable. This will impact the ultrasound transducer and at the same time adversely affect the ultrasound treatment therapy.

In US Pat. No. 4,587,958 (JP58-58034A), a transient operation at the start of vibration is considered, but no consideration is given to a shock when the ultrasonic drive is terminated.
That is, in a medical device, an insulating transformer is interposed between the ultrasonic transducer and the driving device in order to enhance safety, but a large reverse voltage is generated at the end of driving due to the influence of an inductor component of the insulating transformer, The circuit on the driving device side may be adversely affected.

The present invention has been made in view of the above circumstances,
The purpose is to stabilize the vibration amplitude without overshooting when changing the vibration amplitude of the ultrasonic vibrator and when starting and ending the ultrasonic drive. It is an object of the present invention to provide an ultrasonic drive device capable of avoiding an impact, enabling appropriate ultrasonic treatment, and preventing a reverse voltage at the end of driving to enhance safety.

[0012]

According to the present invention, there is provided an ultrasonic driving apparatus comprising: an oscillating means for generating a high frequency signal for driving an ultrasonic vibrator; a rising portion which gradually changes until a predetermined level is reached ; Level plateau and said predetermined
An amplitude setting signal generating means for generating an amplitude setting signal oscillation amplitude gradually changing has a fall portion the ultrasonic transducers from the level set to the predetermined level, the ultrasonic vibration
A signal corresponding to the vibration amplitude of the rotor is detected and the
Means for outputting a signal of a corresponding level, and the output signal
Means for comparing the level of the amplitude setting signal with the level of the amplitude setting signal
And controls the amplitude of the high-frequency signal according to the comparison result.
Means.

[0013]

[Action] Start-up that gradually changes until it reaches a predetermined level
The beveled portion, the flat portion of the predetermined level and the predetermined level
The vibration amplitude of the ultrasonic transducer is set according to an amplitude setting signal having a falling portion that gradually changes from the bell .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a handpiece having an ultrasonic vibrator 2 formed by laminating a plurality of piezoelectric elements and a plurality of electrodes in contact with both sides of each of the piezoelectric elements. The ultrasonic transducer of the acoustic transducer 2 is amplified by the horn 3 and transmitted to the probe 4.

Reference numeral 11 denotes an oscillating unit which emits a high frequency signal for driving ultrasonic waves. The high-frequency signal is amplified by the amplification control unit 12, passed through the current detection unit 13, and supplied to the ultrasonic transducer 2.

The amplification control unit 12 includes a differential amplifier 1 described later.
The amplification degree changes according to the output voltage level of No. 4.

The current detector 13 detects a current value of the high-frequency signal and outputs a voltage Vi having a level corresponding to the detection result. The current value detected here corresponds to the vibration amplitude of the ultrasonic transducer 2. That is, the vibration amplitude is proportional to the high-frequency current.

The output voltage Vi of the current detector 13 is applied to a negative input terminal (-) of a differential amplifier 14 which is a comparator.

Reference numeral 15 denotes an amplitude setting signal generator which generates a voltage signal of a predetermined level for setting the vibration amplitude of the ultrasonic transducer 2 as an amplitude setting signal. This amplitude setting signal is supplied to the positive input terminal (+) of the differential amplifier 14 through the level adjusting unit 16.

The level adjusting section 16 is for manually setting the voltage level of the amplitude setting signal, and functions as a means for changing the set value for the vibration amplitude.

The differential amplifier 14 outputs a voltage of a predetermined level corresponding to the difference between the input voltage level to the positive input terminal (+) and the input voltage level to the negative input terminal (-). This output voltage is supplied to the amplification control unit 12.

FIG. 2 shows a specific example of the amplitude setting signal generator 15 and the level adjuster 16.

First, the amplitude setting signal generator 15 includes a pulse signal generator 21 for generating a rectangular pulse signal,
2, an integrating circuit including an operational amplifier 23 and a capacitor 24, and a Zener diode 25, in which the pulse signal of the pulse signal generator 21 is integrated by the integrating circuit, and the Zener diode 25 converts the pulse signal into a constant voltage. The signal is converted to a gentle trapezoidal wave signal and output.

Here, the rectangular pulse signal emitted from the pulse signal generator 21 corresponds to switching the set value for the vibration amplitude of the ultrasonic transducer 2 between zero and a predetermined value alternately.

The level adjusting section 16 has a sliding resistor 26, and can continuously change the voltage level of the amplitude setting signal.

Next, the operation will be described with reference to FIG.

A high-frequency signal is emitted from the oscillating unit 11, amplified by the amplification control unit 12, and sent to the ultrasonic transducer 2 through the current detecting unit 13. Thereby, the ultrasonic transducer 2 is driven.

At this time, the current value of the high-frequency signal is detected by the current detection unit 13, and a voltage Vi having a level corresponding to the detection result is sent to the differential amplifier 14.

On the other hand, a trapezoidal wave signal having a gradual rise and fall is generated as an amplitude setting signal from an amplitude setting signal generating section 15, which is appropriately adjusted to a voltage Vd by a level adjusting section 16, and supplied to a differential amplifier 14. Sent.

Thus, a voltage having a level corresponding to the difference between the voltage Vd and the voltage Vi is output from the differential amplifier 14, and the amplification degree of the amplification control unit 12 changes according to the output voltage of the differential amplifier 14.

Therefore, the voltage V based on the amplitude setting signal
The current of the high-frequency signal is limited by the envelope corresponding to the waveform d, and the ultrasonic transducer 2 is burst-driven with a stable vibration amplitude.

The set value for the vibration amplitude is switched between zero and a predetermined value. However, the voltage level of the amplitude setting signal gradually increases and gradually decreases, so that the vibration amplitude of the ultrasonic transducer 2 is reduced. It gradually increases without overshoot and gradually decreases. That is, it is possible to avoid an impact on the ultrasonic vibrator 2 and to perform an appropriate ultrasonic treatment.

At the end of the ultrasonic drive, the current of the high-frequency signal gradually decreases, so that even if there is an inductor component of the insulating transformer, a large reverse voltage does not occur in the inductor component, and the drive of the drive device is not affected. Safety can be ensured.

The case where the set value for the vibration amplitude is switched between zero and a predetermined value has been described above as an example, but the same effect can be obtained when the set value for the vibration amplitude is switched between high and low. Can be FIG. 4 shows a signal waveform in this case.

The amplitude setting signal generator 15 includes:
As shown in FIG. 5, a pulse signal generator 21 for generating a rectangular pulse signal and an integrating circuit including a resistor 22 and a capacitor 24 are provided. The pulse signal of the pulse signal generator 21 is simply integrated by the integrating circuit. A configuration in which the output is performed may be adopted. FIG. 6 shows a signal waveform in this case.

As shown in FIG. 7, a D / A (digital / analog) converter 28 is employed as the amplitude setting signal generator 15, and the set value changes stepwise according to external input data. May be configured to generate an amplitude setting signal. FIG. 8 shows a signal waveform in this case.

Next, a second embodiment of the present invention will be described.

Here, a high-frequency signal for driving ultrasonic waves emitted from an oscillator (OSC) 31 is supplied to a voltage control amplifier (V
CA) 32, and further amplified by a power amplifier 33, and supplied to the ultrasonic transducer 2 via an insulating transformer.

A current sensor 35 is provided in a current path between the power amplifier 33 and the insulating transformer 34, and a contact 39a of a relay 39 described later is inserted and connected.

The amplification degree of the voltage control amplifier 32 changes according to the output voltage level of a differential amplifier 36 described later.

The current sensor 35 detects the current value of the high-frequency signal and outputs a voltage Vi at a level corresponding to the detection result. The current value detected here corresponds to the vibration amplitude of the ultrasonic transducer 2.

The output voltage Vi of the current sensor 35 is applied to a negative input terminal (-) of a differential amplifier 36 which is a comparator.

Reference numeral 37 denotes an amplitude setting signal generator which generates a voltage signal of a predetermined level for setting the vibration amplitude of the ultrasonic transducer 2 as an amplitude setting signal. This amplitude setting signal is a trapezoidal wave signal whose rising and falling are gentle. Then, the amplitude setting signal is supplied to the positive input terminal (+) of the differential amplifier 36 through the level adjusting unit 40.

The amplitude setting signal generating section 37 has a switch 38 and a relay 39 attached thereto. The amplitude setting signal generating section 37 generates an amplitude setting signal in response to the ON operation of the switch 38, energizes the relay 39, and switches the switch 38. The amplitude setting signal falls in response to the turning-off operation, and the relay 39 is deactivated after a predetermined time t (after the amplitude setting signal has dropped to zero level).

The level adjuster 40 is for manually setting the voltage level of the amplitude setting signal, and functions as a means for changing the set value for the vibration amplitude.

The differential amplifier 36 outputs a voltage of a predetermined level corresponding to the difference between the input voltage level to the positive input terminal (+) and the input voltage level to the negative input terminal (-). This output voltage is supplied to the voltage control amplifier 32.

The operation will be described with reference to FIG.

When the switch 38 is turned on, an amplitude setting signal (voltage Vc) having a gradual rise is generated from the amplitude setting signal generator 37, and the amplitude setting signal is supplied to the level adjuster 40.
The value is appropriately adjusted to d and sent to the differential amplifier 36.

At the same time, the relay 39 is energized and its contact 39a is turned on.

On the other hand, a high-frequency signal is emitted from the oscillator 31,
Amplified by The amplified high-frequency signal is sent to the ultrasonic transducer 2 via the ON-state contact 39a and the insulating transformer 34. Thereby, the ultrasonic transducer 2 is driven.

At this time, the current value of the high-frequency signal is detected by the current sensor 35, and a voltage Vi having a level corresponding to the detection result is sent to the differential amplifier 36.

Thus, a voltage having a level corresponding to the difference between the voltage Vd and the voltage Vi is output from the differential amplifier 36, and the voltage control amplifier 3
The amplification degree of No. 2 changes.

Therefore, the voltage V based on the amplitude setting signal
The current of the high-frequency signal is limited by the envelope corresponding to the waveform d, and the ultrasonic vibrator 2 is driven with a stable vibration amplitude.

That is, the voltage level of the amplitude setting signal gradually increases, and the vibration amplitude of the ultrasonic transducer 2 gradually increases without overshooting. Therefore, it is possible to avoid an impact on the ultrasonic vibrator 2 and to perform appropriate ultrasonic treatment.

In FIG. 10, the output voltage Vi of the current detection unit 13 greatly increases in the latter period, but this is because the voltage Vd is increased by operating the level adjustment unit 40.

When the switch 38 is turned off, the amplitude setting signal issued from the amplitude setting signal generator 37 starts to fall, and the vibration amplitude of the ultrasonic transducer 2 gradually decreases. When a certain time t has elapsed from the start of the fall, the relay 39 is deenergized, and the contact 39a is turned off.

As described above, since the current of the high-frequency signal gradually decreases at the end of the ultrasonic driving, even if the inductor component of the insulating transformer 34 is present, it is possible to prevent a large reverse voltage from being generated. The safety of the drive device can be ensured.

In the second embodiment, the switch 38
When the switch 38 is turned off, the ultrasonic drive is terminated. When the switch 38 is turned off, the ultrasonic drive is terminated. And the same burst drive as in the first embodiment may be performed.

Next, a third embodiment of the present invention will be described.

Here, resonance frequency tracking control by a PLL circuit (phase locked loop) is employed as an oscillator for emitting a high frequency signal.

That is, the voltage controlled oscillator (VCO) 51
The high frequency signal for ultrasonic driving emitted from the amplifier is amplified by a voltage control amplifier (VCA) 52 and further amplified by a power amplifier 53
And supplies it to the ultrasonic transducer 2 via the current / voltage detection unit 54 and the insulating transformer 55.

The voltage-controlled oscillator 51 emits a high-frequency signal having a frequency corresponding to the level of the input voltage.

The amplification degree of the voltage control amplifier 52 changes according to the output voltage level of the differential amplifier 60 described later.

The current / voltage detector 54 detects the current value of the high-frequency signal and outputs a voltage Vi at a level corresponding to the detection result, and detects the voltage value of the high-frequency signal and outputs a voltage at a level corresponding to the detection result. Vv is output. The voltages Vi and Vv are sent to the phase comparison unit 56.

The phase comparing section 56 obtains the current phase and the voltage phase of the high-frequency signal from the voltages Vi and Vv, and outputs a signal having a voltage level corresponding to the phase difference. This output signal is sent to the voltage controlled oscillator 51 via the low-pass filter 57 and one contact of the changeover switch 58, and
The signal is sent to the hold circuit 59.

The changeover switch 58 is, for example, a bidirectional contact of a relay. When an amplitude setting signal of an amplitude setting signal generator 61 described later is at a high level, one of the contacts is closed as shown in FIG. When it reaches the level, it switches and the other contact closes.

The hold circuit 59 stores the voltage level of the output signal of the low-pass filter 57 when the amplitude setting signal of the amplitude setting signal generator 61 is at a high level, and stores the stored level when the amplitude setting signal becomes zero. It outputs voltage signals of the same level. This output data is sent to the voltage controlled oscillator 51 via the other contact of the changeover switch 58.

On the other hand, the output voltage Vi of the current / voltage detector 54
Is applied to the negative input terminal (−) of the differential amplifier 60 which is a comparator.

The amplitude setting signal generator 61 generates a voltage signal of a predetermined level for setting the vibration amplitude of the ultrasonic transducer 2 as an amplitude setting signal. Similarly, a trapezoidal wave signal having a gradual rise and fall is sequentially output. However, the amplitude setting signal generator 61 has a switch 62 attached thereto, and has a function of generating an amplitude setting signal only when the switch 62 is turned on.

The amplitude setting signal is supplied to the positive input terminal (+) of the differential amplifier 60 through the level adjusting section 63.

The level adjusting section 63 is for manually setting the voltage level of the amplitude setting signal, and functions as a means for changing the set value for the vibration amplitude.

The differential amplifier 60 outputs a voltage of a predetermined level corresponding to the difference between the input voltage level to the positive input terminal (+) and the input voltage level to the negative input terminal (-). This output voltage is supplied to the voltage control amplifier 52.

The operation will be described.

When the switch 62 is turned on, a trapezoidal wave signal having a gradual rise and fall is sequentially generated as an amplitude setting signal from the amplitude setting signal generating section 61, and the trapezoidal signal is appropriately adjusted to the voltage Vd by the level adjusting section 63. It is adjusted and sent to the differential amplifier 60.

On the other hand, a high frequency signal is emitted from the voltage controlled oscillator 51 and is amplified by the voltage controlled amplifier 52 and the power amplifier 53. This amplified high frequency signal is
The signal is sent to the ultrasonic transducer 2 via the current / voltage detector 54 and the insulating transformer 55. Thereby, the ultrasonic vibrator 2
Is driven.

At this time, the current value of the high-frequency signal is detected by the current / voltage detector 54, and a voltage Vi having a level corresponding to the detection result is sent to the differential amplifier 60.

In this manner, a voltage of a level corresponding to the difference between voltage Vd and voltage Vi is output from differential amplifier 60, and voltage control amplifier 5 outputs a voltage corresponding to the output voltage of differential amplifier 60.
The amplification degree of No. 2 changes.

Therefore, the voltage V based on the amplitude setting signal
The current of the high-frequency signal is limited by the envelope corresponding to the waveform d, and the ultrasonic transducer 2 is burst-driven with a stable vibration amplitude.

The set value for the vibration amplitude is switched between zero and a predetermined value. However, the voltage level of the amplitude setting signal gradually increases and gradually decreases, so that the vibration amplitude of the ultrasonic transducer 2 is reduced. It gradually increases without overshoot and gradually decreases. That is, it is possible to avoid an impact on the ultrasonic vibrator 2 and to perform an appropriate ultrasonic treatment.

At the end of the ultrasonic drive, the current of the high-frequency signal gradually decreases, so that even if there is an inductor component of the insulating transformer, a large reverse voltage is not generated there, and Safety can be ensured.

By the way, a signal of a voltage level corresponding to the current phase and the voltage phase of the high-frequency signal is output from the phase comparator 56.

This output signal is fed back to the voltage controlled oscillator 51 when the amplitude setting signal is at a high level, that is, when one contact of the changeover switch 58 is closed. As a result, a PLL circuit (phase locked loop) is formed, the ultrasonic transducer 2 is driven at the resonance point, and the energy conversion efficiency is increased.

The voltage level of the output signal of the phase comparator 56 is sequentially stored in the hold circuit 59. When the amplitude setting signal is at the zero level, that is, when the other contact of the switch 58 is closed, the hold circuit 59 is closed. Is fed back to the voltage controlled oscillator 51. As a result, the PLL circuit (phase synchronization circuit) is configured without interruption, and the efficient resonance point driving of the ultrasonic transducer 2 is continued.

When the switch 62 is turned off, the generation of the amplitude setting signal from the amplitude setting signal generator 61 is released, and
The ultrasonic drive ends.

[0086]

As described above, according to the present invention, the oscillating means for generating the high frequency signal for driving the ultrasonic vibrator, the rising portion which gradually changes until reaching the predetermined level, Flat part and the predetermined level
An amplitude setting signal generating means for generating an amplitude setting signal oscillation amplitude gradually changing has a trailing portion wherein the ultrasonic transducer is set to the predetermined level from the ultrasonic vibrator
Detects the signal corresponding to the vibration amplitude and responds to the detection result.
Means for outputting a signal of a certain level, and a level of the output signal.
Means for comparing the level of the amplitude setting signal with the level of the amplitude setting signal.
Means for controlling the amplitude of the high-frequency signal according to the comparison result of
Since it has a step, it can change the vibration amplitude of the ultrasonic transducer,
At the start and end of the ultrasonic drive, the vibration amplitude can be stabilized without overshooting, thereby avoiding the shock to the ultrasonic vibrator and enabling appropriate ultrasonic treatment and treatment, and the drive end. It is possible to provide an ultrasonic driving device capable of preventing a reverse voltage at the time and improving safety.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing a specific configuration of an amplitude setting signal generator and a level adjuster in the first embodiment.

FIG. 3 is a signal waveform diagram for explaining the operation of the first embodiment.

FIG. 4 is a signal waveform diagram for explaining the operation of a modification of the first embodiment.

FIG. 5 is a diagram showing a configuration of a modified example of the amplitude setting signal generator in the first embodiment.

FIG. 6 is a signal waveform diagram for explaining the operation of FIG. 5;

FIG. 7 is a diagram showing a configuration of another modification of the amplitude setting signal generation unit in the first embodiment.

FIG. 8 is a signal waveform diagram for explaining the operation of FIG. 7;

FIG. 9 is a diagram showing the overall configuration of a second embodiment of the present invention.

FIG. 10 is a signal waveform diagram for explaining the operation of the second embodiment.

FIG. 11 is a diagram showing an entire configuration of a third embodiment of the present invention.

FIG. 12 is a diagram showing a vibration amplitude of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Handpiece, 2 ... Ultrasonic vibrator, 11 ... Oscillator,
12: amplification control unit, 13: current detection unit, 14: differential amplifier (comparator), 15: amplitude signal generation unit, 16: level adjustment unit

Claims (1)

(57) [Claims] An oscillating means for generating a high-frequency signal for driving an ultrasonic vibrator; a rising portion gradually changing until a predetermined level is reached ;
From the flat part of the predetermined level and the predetermined level
An amplitude setting signal generating means for generating an amplitude setting signal for setting the vibration amplitude of the ultrasonic transducer has a fall portion which gradually changes to the predetermined level, corresponding to the vibration amplitude of the ultrasonic vibrator Signal is detected
Means for outputting a signal having a level corresponding to the detection result, and the level of the output signal and the level of the amplitude setting signal.
Means for comparing , and controlling the amplitude of the high-frequency signal in accordance with the result of the comparison
Ultrasonic driving device characterized by comprising: a means.