JPH04247268A - Ultrasonic vibrating device - Google Patents

Abstract

PURPOSE:To provide the ultrasonic vibrating device which can drive an ultrasonic vibrator transducer capable of assuring safety to a patient with simple constitution. CONSTITUTION:Inductances 10, 11 for boosting on an electrode 33a side which does not come into contact with the patient are interposed between an insulating and boosting transformer 17 which insulates the switching outputs of switching means 4, 5 and the ultrasonic vibrator transducer 1 and the electrode 33b on the side in contact with the patient is directly connected to the insulating and boosting transformer 17 so that a large voltage is not impressed to the patient.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibrator for driving an ultrasonic vibrator used in an ultrasonic dissolution accelerator or the like.

0002

2. Description of the Related Art Conventionally, in ultrasonic transducer drive circuits in this type of ultrasonic treatment apparatus, a compact and highly efficient switching drive system has often been used. For example, as disclosed in US Pat. No. 4,736,192, there is a device in which the frequency of a resonant circuit formed by an inductance connected in series with a piezoelectric element and a capacitance of the piezoelectric element is made to match the resonant frequency of the piezoelectric element. In addition, in order to overcome the same difficulty in reducing the resonance frequency due to a single inductance due to variations in the parameters of the piezoelectric element, and at the same time suppress the generation of harmonic components, a proposal was made in Japanese Patent Application No. 1-74429. There is a drive circuit in which a parallel circuit of an inductance and a capacitor is connected to a power supply terminal of a switching means to form a series circuit with the inductance, and an ultrasonic transducer is connected in parallel to the switching means.

Furthermore, the above-mentioned Japanese Patent Application No. 1-74429,
As shown in Japanese Patent Publication No. 2-48255, there is a device that drives an ultrasonic transducer with high efficiency by alternately turning on and off two switching means. A conventional example will be described below with reference to the drawings.

FIG. 5 shows a block configuration of a switching type ultrasonic vibrator drive circuit (also referred to as an ultrasonic vibrator). In this type of ultrasonic transducer drive circuit, an ultrasonic transducer 1 is connected to a switching means 2, and the switching action of the switching means 2 is outputted from a switching means drive circuit 3 connected to the switching means 2. Controlled by a drive signal. FIG. 6 shows a conventional example of a switching type ultrasonic transducer drive circuit. As shown in the figure, the ultrasonic transducer 1 made of a piezoelectric element has an inductance 1a, a capacitance 1b,
It is represented by an equivalent circuit in which a capacitor 1d is connected in parallel to a series resonant circuit of a resistor 1c.

For example, a parallel circuit of a capacitor 6 and an inductance 7 and a parallel circuit of a capacitor 8 and an inductance 9 are connected to the power supply terminals of the switching means 4 and 5, which are made of power MOS FETs, respectively. and 5 form a series circuit with inductances 10 and 11, respectively, and are connected in parallel to the ultrasonic transducer 1. In addition, power MOS
A resistor R is connected between the gate and source of the FET. In this drive circuit, switching means 4 and 5
Due to the switching action, a high frequency voltage having an amplitude higher than the power supply voltage is excited in the inductances 7 and 9, and frequency components higher than the switching frequency are removed by the capacitors 6 and 8 connected in parallel.

This high frequency excitation voltage has an inductance of 10
and 11, and at the same time, the cutoff frequency is set in advance to be the driving frequency, and is composed of an inductance component due to the sum of the inductances 10 and 11, and a parallel capacitance 1d of the ultrasonic transducer 1. L
The C filter suppresses the generation of unnecessary harmonics. Further, the switching means 4 and 5 are push-pull switched by the switching means driving circuit 3, and the ultrasonic transducer 1 is provided with two normal single switching switches.
Double the driving voltage is applied. Then, ultrasonic waves are emitted to a patient or the like with which this ultrasonic transducer 1 comes into contact.

FIG. 7 shows a circuit for switching and driving an ultrasonic transducer 1 having a relatively low resonance frequency. This ultrasonic transducer drive circuit is constructed by eliminating the parallel circuit of capacitor 6 and inductance 7 connected to the output terminals of switching means 4 and 5 and the parallel circuit of capacitor 8 and inductance 9 in the drive circuit shown in FIG. Insulation/step-up transformers 17 having a transformation ratio of are connected in parallel, and a DC power supply 16 is connected to the center tap of the isolation/step-up transformers 17. The voltage of the DC power source is push-pull switched by the switching means 4 and 5 at the resonant frequency of the ultrasonic transducer 1 in the same way as before, and the output terminal of the isolation/step-up transformer 17 has a voltage that is twice the step-up ratio of the power source voltage. Furthermore, a voltage of twice the amplitude is excited. As before, this excitation voltage is boosted by the inductances 10 and 11, and at the same time, an LC filter consisting of the inductances 10 and 11 and the parallel capacitance 1d of the ultrasonic transducer 1 generates a rectangular voltage waveform. The spike-like current waveform is converted into a sine wave at the resonance frequency of the ultrasonic transducer 1 and applied to the ultrasonic transducer 1.

[0008]

In the conventional example shown in FIG. 6, parallel circuits of a capacitor 6 and an inductance 7, and a capacitor 8 and an inductance 9 are provided at the power terminals of the switching means 4 and 5 to eliminate harmonic components. However, compared to the linear amplifier system, the drive output waveform still contains more harmonic components, the leakage current between the patient and the earth is large, and there is a problem in terms of electrical safety as a medical device.

To solve this problem, it is possible to insert an isolation transformer 17 between the drive circuit and the ultrasonic transducer 1 to insulate the output as shown in FIG. By simply doing so, it is not possible to suppress the patient leakage current from the ultrasonic transducer 1 driven by high voltage or large current to below a generally defined reference value. In addition, an inductance of 10 is connected to the secondary circuit output terminal of the isolation transformer 17.
, 11, the drive voltage is further excited, making it difficult to sufficiently ensure patient safety.

The present invention has been made in view of the above-mentioned points, and is an ultrasonic transducer capable of driving an ultrasonic transducer at high voltage and large current with a simple configuration and in an electrically safe state for the patient. An object of the present invention is to provide a sonic vibration device.

[0011]

[Means for Solving the Problems and Effects] In order to solve the above-mentioned problems, the present invention provides an ultrasonic vibrator that drives an ultrasonic vibrator by a switching operation of a switching means, in which one or more switching means perform switching. , a switching means drive circuit for driving this, an isolation/step-up transformer for insulating and boosting the switching output, an ultrasonic vibrator driven by the isolated switching output, the isolation/step-up transformer and the ultrasonic vibration. Equipped with an inductance provided between the child and the child,
By configuring the inductance to be connected to the electrode side of the ultrasonic transducer that is not in contact with the patient, the electrode of the ultrasonic transducer directly connected to one end of the isolation transformer is brought into contact with the patient, and the inductance is further excited. The other electrode to which the voltage is applied through the electrode is made not to come into contact with the patient, thereby reducing the potential difference between the patient and the ground, reducing leakage current, and ensuring safety for the patient.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. 1 to 3 relate to a first embodiment of the present invention, FIG. 1 shows a circuit diagram of the first embodiment, and FIGS. 2 and 3 show an example of use of the first embodiment. In the ultrasonic vibrator 21 of the first embodiment shown in FIG. 1, the gates of switching means 4 and 5 such as power MOSFETs are connected to the first and second output terminals of the switching means drive circuit 3, respectively. The sources of switching means 4 and 5 are each grounded. Also, each drain is connected to the primary circuit side and the secondary circuit side.
It is connected to both ends of the primary circuit of an isolation/step-up transformer 17 that insulates the next circuit and boosts the voltage. Further, a predetermined voltage is applied to the center tap of the insulation/step-up transformer 17 from the DC power supply 16.

Note that a resistor R is connected between the gate and the source. The above insulation/step-up transformer 17-2
Inductances 10 and 11 are connected in series to one of both terminals of the next circuit, that is, to one of the output ends. These inductances 10 and 11 are the parallel capacitance 1 of the ultrasonic transducer 1
d (see FIG. 6) to form an LC filter that is cut off at the resonant frequency, that is, the switching frequency, of the ultrasonic transducer 1, and to further boost (excite) the voltage at the output end of the isolation/step-up transformer 17. It is formed by one or more coils. The electrode 33a of the ultrasound transducer 1 that does not contact the patient has the inductance 10,
11, the ultrasonic transducer 1 is in electrical contact with the patient, and the electrode 33b, which has the same potential as the patient, is connected to the other output end of the insulation/step-up transformer 17.

The ultrasonic vibrator 21, that is, the ultrasonic vibrator drive circuit according to the first embodiment of the present invention configured as described above, is similar to the explanation in FIG.
is driven at a driving frequency that matches its resonant frequency. In the drive circuit of FIG. 6, an inductance 11 is inserted in the circuit portion that has the same potential as the patient, and a voltage is excited in the inductance 11 as well. However, in this embodiment, the inductance 10 necessary to configure the LC filter is , 11 is
All of them are provided on the electrode 33a side of the ultrasound transducer 1 that is insulated from (does not come into contact with) the patient.

Therefore, the ultrasonic transducer 1, shown as P in FIG. The driving voltage is not excited to a large extent in the part where the potential is the same as that of the electrode 33a on the side not in contact with the patient.
Its potential can be kept low compared to . That is, since the potential difference between the part that has the same potential as the patient and the ground becomes small, it is possible to suppress the patient leakage current flowing from the patient in contact with this part to the ground.

Next, an apparatus to which the first embodiment is applied will be specifically explained. FIG. 2 shows an ultrasound applicator device 31 for gallstone dissolution. The ultrasonic transducer 1 has two piezoelectric elements 32, 32 bonded together with the common electrode 33a on the inside and the other electrode 33b, 33b on the outside. The inner electrode 33a is connected to the inductance 11, and the outer electrodes 33b are directly connected to one terminal of the insulation/step-up transformer 17.

A backing material 34 is attached to one surface of the outer electrodes 33b, 33b, and the back surface of a metal elastic block 35 is attached to the other electrode surface, and the front side of this elastic block 35 is made of metal. It is fixed to a vibrator holding frame 37 via a magnetic diaphragm 36. The diaphragm 36 is further covered with a head membrane 39 containing an ultrasonic transmission medium 38 such as water, and the base end of the head membrane 39 is fixed to the vibrator holding frame 37. This head film 39 is
It is placed in contact with the body of the patient 40, etc., at a position opposite to the site where gallstones are to be dissolved, and by irradiating ultrasound, it is possible to apply a gallstone dissolving agent and vibration to the stones, thereby promoting gallstone dissolution. .

In the case of this device 31, the patient 40 is in contact with the earth and therefore the electrode 3 in contact with the patient 40
It is desired that the drive voltage on the 3b side be as low as possible. In this first embodiment, safety can be ensured to a certain extent by forming the head film 39 with an insulating material, but this film 3
9 is damaged, the electrode 33b that contacts the patient 40 via the elastic block 35 etc. is directly connected to the insulating/step-up transformer 17 and connected to the patient 40. The ultrasonic transducer 1 can be driven with a high voltage and a large current while the voltage is suppressed lower than that on the side of the electrode 33a which is not connected.

In this case, since the potential difference between the part having the same potential as the patient 40 and the ground becomes small, it becomes possible to suppress the patient leakage current flowing from the patient 40 in contact with this part to the ground, Safety can be ensured even in the unlikely event of an emergency. In addition, the simple configuration makes it possible to realize a highly safe device and to make it compact.

FIG. 3 shows a second device, such as an ultrasonic probe device 41, to which the first embodiment is applied. Note that the same members as in FIG. 2 are indicated by the same symbols. A horn 43 is fixed to the surface of the elastic block 35 via a horn fixing member 42 . This horn 43 is made of metal and amplifies the ultrasonic waves excited by the ultrasonic vibrator 1. The proximal end of a metal probe 44 is fixed to the top of the horn 43, and the ultrasonic waves transmitted by the probe 44 can be irradiated onto the patient 40 etc. that comes into contact with the distal end surface of the probe 44. Ultrasonic waves from a surface can be used to perform cancer treatment using shock waves. According to the first embodiment, it is possible to solve the electrical safety problem for patients that could not be solved simply by inserting a transformer. In other words, the ultrasonic transducer can be driven at high voltage and current, and the patient leakage current from the ultrasonic transducer can be suppressed to below the generally established standard value. An efficient ultrasonic transducer drive circuit can be realized.
FIG. 4 shows a second embodiment of the present invention, and the previous embodiment is an ultrasonic transducer drive suitable for driving a relatively low-frequency transducer such as a Langevin transducer or a bolted Langevin transducer. However, in this example, PZT
This figure shows an ultrasonic vibrating device 41 suitable for driving an ultrasonic vibrator having a relatively high resonance frequency such as the above.

In FIG. 4, for example, a power MOS
A parallel circuit of a capacitor 6 and an inductance 7, and a parallel circuit of a capacitor 8 and an inductance 9 are connected to the power supply terminals of the switching means 4 and 5, which are FETs, etc., and the switching means 4 and 5 are insulated, respectively. - Connected to each end of the primary side of the step-up transformer 17. In addition, the insulation/step-up transformer 17
One of the output terminals on the secondary side of is connected with inductances 10 and 11 in series, as in the previous embodiment. The inductances 10 and 11 are the parallel capacitance 1 of the ultrasonic transducer 1.
It is formed of a single coil or a plurality of coils so as to constitute an LC filter having a cutoff at the resonance frequency, that is, the switching frequency, of the ultrasonic transducer 1 together with d.

Further, as in the previous embodiment, the ultrasonic transducer 1
The electrode 33a that is not in contact with the patient has the inductance 10
. . In this embodiment as well, the driving voltage is not excited much in the part indicated by P in the figure which has the same potential as the patient, so the potential is suppressed lower than that of the electrode 33a on the side not in contact with the patient, and the potential is the same as that of the patient. The potential difference between the potential part and the ground becomes small, making it possible to suppress the patient leakage current flowing from the patient in contact with this part to the ground.

Therefore, this embodiment also provides the same effects as the previous embodiment.

In the above-described embodiment, the isolation/step-up transformer 17 may simply provide insulation, and step-up may be performed using the inductances 10 and 11 (or only one of them may be used).

[0025] The present invention is applicable to ultrasonic or Ultrasonic transducer drive circuit of a shock wave generator, more specifically, driving any ultrasonic transducer in an ultrasonic generator that has an ultrasonic transducer such as a piezoelectric element or a magnetostrictive element as an ultrasonic (shock wave) generation source. Can be widely applied to circuits.

[0026]

[Effects of the Invention] As explained above, according to the present invention, the ultrasonic transducer can be driven with high voltage and large current, and the patient leakage current from the ultrasonic transducer can be suppressed to below the generally defined reference value. Therefore, it is possible to realize an electrically safe and highly efficient ultrasonic transducer drive circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a switching type ultrasonic vibration device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing the main parts of an ultrasonic applicator device to which the first embodiment is applied.

FIG. 3 is a configuration diagram showing the main parts of an ultrasound probe device to which the first embodiment is applied.

FIG. 4 is a circuit diagram showing the configuration of a switching type ultrasonic vibration device according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing the configuration of a conventional switching type ultrasonic vibration device.

FIG. 6 is a circuit diagram showing the configuration of a conventional switching type ultrasonic vibration device.

FIG. 7 is a circuit diagram showing another configuration example of a conventional switching type ultrasonic vibration device.

[Explanation of symbols]

1... Ultrasonic transducer 3... Switching means drive circuit 4... Switching means (power MOS FET)
5...Switching means (power MOS FET)
6...Capacitor 7...Inductance 8...Capacitor 9...Inductance 10...Inductance 11...Inductance 16...DC power supply 17...Insulation/step-up transformer 21...Ultrasonic vibration device

Claims (1)

[Claims] 1. An ultrasonic vibrator that ultrasonically vibrates an output part that comes into contact with a living body, etc., comprising: switching means for generating an AC rectangular voltage; An isolation transformer that boosts and outputs voltage to the next side, an ultrasonic vibrator having two electrode surfaces each connected to the two output terminals of the secondary side, and a mechanical is connected to the transducer and is provided only between a transmission means for transmitting vibrations to the output section, and the other electrode surface that does not contact the transmission means and an output terminal connected to that electrode surface, and is connected to the vibrator. An ultrasonic vibration device characterized by comprising an inductance for exciting a supplied voltage and making it a substantially sinusoidal wave.