JP2006255621A - Ultrasonic generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable an ultrasonic generator to control the drive properly and simply derive the energy loss in an oscillation block in a highly stably driving the ultrasonic generator. <P>SOLUTION: The ultrasonic generator is provided with an oscillator element 1, the ultrasonic oscillation block 4 constituted of a horn 3 bonded to the oscillator element 1 and transmitting ultrasonic waves from an ultrasonic radiating surface to a material to be treated and a driving circuit 7 driving the above. The driving circuit 7 has an efficiency deriving part 12 deriving the efficiency of the oscillation block 4 from the value of impedance or electric current in the resonant frequency of the oscillation block 4 and the electric input to the oscillation block 4 is controlled so as to obtain a desired ultrasonic output based on the efficiency derived in the efficiency deriving part 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generates vibration energy in the ultrasonic region in the horn and causes the ultrasonic wave to act on the object to be processed in contact with the horn, thereby processing, joining, cleaning, promoting agent penetration, stirring, dispersing, emulsifying, fogging. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for discriminating whether an operation is highly stable or unstable and performing a desired operation in an ultrasonic generator that performs ultrasonic processing such as conversion and cosmetics.

  As a conventional general ultrasonic generator, for example, the one disclosed in Patent Document 1 is known. As shown in FIG. 16, this type of ultrasonic generator 10 includes an ultrasonic vibrator 1 (hereinafter referred to as a vibrator) that converts electrical vibration into mechanical vibration, and vibration of mechanical vibration converted by the vibrator 1. Electric vibration is supplied to an ultrasonic vibration block 4 (hereinafter referred to as a vibration block) composed of a horn 3 having a radiation surface for transmitting energy as ultrasonic acoustic energy to a target location, and to the vibrator 1 in the vibration block 4. Depending on the application, ultrasonic waves are transmitted to the living body 2 that is a processing target via an ultrasonic transmission medium 5 such as water, gel, or gel.

  In the energy transmission flow in this ultrasonic transmission process, as shown in FIG. 17 using an ultrasonic cosmetic device as an example, electrical vibration (electric energy) to mechanical vibration (kinetic energy), and mechanical vibration (kinetic energy) to ultrasonic waves. Since it is converted into acoustic energy and finally subjected to target ultrasonic treatment, energy loss occurs in the process of each energy conversion.

  As shown in FIG. 18, the vibration block is mainly composed of a method in which the vibrator 1 is bonded to the horn 3 with an adhesive 6a, and as shown in FIG. There is a method of fastening and fixing to No. 3. The former is mainly used for a high frequency type of several hundred kHz or more, and the latter is mainly used for a low frequency type of about 100 kHz or less.

  In the configuration of the vibration block, as shown in FIG. 20, in addition to requiring a precise design for each of the horn 3 and the vibrator 1, completely different members such as the vibrator 1 and the horn 3 are bonded (mechanical). In order to prevent the air layer interference, an adhesive 6a of about 20 μm and a layer of lubricating oil exist between the vibrator 1 and the horn 3 to balance the vibration block 4 as a whole. It becomes a factor that breaks down and hinders quantitative determination of ultrasonic vibration energy transmission.

  Also, when driving the device, in order to prevent breakage of the vibrator power supply lead wire, vibration isolation of the housing, waterproofing of the vibration block, etc., there are many cases where a part of the vibration block is protected with silicon rubber, etc. Even in this part, an indefinite amount of ultrasonic vibration energy loss occurs.

  Also, the loss of ultrasonic vibration energy mainly causes vibration block heat generation. Therefore, for each vibration block of the ultrasonic generator, the sound output is directly measured using an ultrasonic sound output measuring device, and the difference between the electrical input and the sound output is the loss in the vibration block. Although it is conceivable to control the power to be supplied, it takes a lot of time for adjustment.

  In the vibration block, the state is not always constant for many years, and the rate of ultrasonic energy loss varies depending on the deterioration of components and the environment. It was difficult to transmit to the site to be treated.

In addition, when manufacturing an ultrasonic generator, a vibration block with an ultrasonic transmission loss exceeding a threshold value must be selected because it cannot exhibit its capability. It is necessary to derive the ultrasonic transmission loss from the relationship between the sound output and the sound output, or to measure the heat generation temperature of the vibration block, and it takes a lot of time for the selection inspection for each vibration block.
JP 2002-345915 A

  As described above, in order to realize a highly stable ultrasonic generator, it is necessary to derive an ultrasonic transmission loss for each vibration block by a simple and low-cost method. Therefore, the present inventors derive the ultrasonic transmission loss of the vibration block by a simple method in order to realize a highly stable vibration block in the ultrasonic generator, to realize a stable acoustic output, We examined a method that can select large vibration blocks, and found that there is a high correlation between the resonance impedance value and the energy conversion efficiency of the vibration block between vibration blocks of the same configuration. By deriving the conversion efficiency, we came up with the idea that vibration energy loss can be easily derived at low cost.

  The present invention is configured as described above, and in driving the ultrasonic vibration block with high stability, the energy loss in the vibration block can be easily derived, and can be appropriately controlled. An object is to provide a sound wave generator.

In order to achieve the above-described object, the present invention includes a vibrator that generates ultrasonic vibrations, and a horn that is bonded to the vibrator and transmits ultrasonic waves to an object to be processed from an ultrasonic radiation surface having an arbitrary shape. In an ultrasonic generator comprising an ultrasonic vibration block (referred to as a vibration block) and a drive circuit for driving them, the drive circuit determines the vibration block from the impedance or current value at the resonance frequency of the vibration block. An efficiency deriving unit for deriving the efficiency of the current, and based on the efficiency derived by the efficiency deriving unit, the electric input to the vibration block is controlled so as to obtain a desired ultrasonic output.
Further, the efficiency deriving unit may calculate the efficiency based on data obtained from a dynamic admittance diagram of the vibration block obtained in advance.
Further, the efficiency deriving unit may calculate the efficiency based on data obtained from calorimetric measurement values of ultrasonic output with respect to the electrical input of the vibration block obtained in advance.
The efficiency deriving unit may calculate the efficiency based on data obtained from a mechanical measurement value of ultrasonic output with respect to an electrical input of the vibration block obtained in advance.
Further, the drive circuit may control a heat generation amount lost as heat generation in the vibration block based on the efficiency calculated by the efficiency deriving unit.

  According to the present invention, the energy conversion efficiency calculation unit is provided in the drive circuit of the ultrasonic generator, and the amount that is difficult to measure, such as the sound output and the calorific value, can be derived from the electrical input. The vibration energy transmission loss in the vibration block can be derived with a simple mechanism, and safe and stable driving can be achieved. Further, if the amount of heat generation is controlled based on the efficiency, not only the effect of ultrasonic waves but also the synergistic effect with heat can be obtained.

  Hereinafter, an ultrasonic generator according to an embodiment of the present invention will be described with reference to the drawings. The present invention embodies the basic structure of the above idea. FIG. 1 shows a configuration of an ultrasonic generator 10 to which the present invention is applied, and FIG. 2 shows a configuration of a vibration block 4 of the same device 10. The ultrasonic generator 10 includes a vibrator 1 serving as a driving source for ultrasonic vibration, a vibration block 4 composed of a horn 3 to which the vibrator 1 is bonded, and transmitting the ultrasonic vibration to a target location. It comprises a drive circuit 7 for driving and a housing 8 including them. The vibration energy converted by the vibration block 4 is converted into acoustic energy from the horn radiation surface, and is applied to the beauty treatment unit of the living body 2 which is contacted through the ultrasonic transmission medium 5 such as water, gel, gel or the like. A sonic vibration b is given.

  The vibrator 1 and the horn 3 in the vibration block 4 are set to an integral multiple of ½ wavelength in ultrasonic vibration, and an alternating voltage (electrical signal a) is applied to both end electrodes 11 of the vibrator 1 through lead wires 12 and 13. Thus, the electric energy is converted into vibration energy (kinetic energy), and the vibration block 4 performs ultrasonic vibration.

  In this specification and drawings, the amplitude of the ultrasonic vibration is described by converting the original longitudinal wave into a transverse wave for convenience of expression, the transmission direction of the ultrasonic vibration is indicated by the direction of the arrow, and the magnitude of the vibration amplitude. And the magnitude | size of vibration energy is shown by the magnitude | size of the arrow. In addition, regarding the negative electrode (ground side) electrode of the vibrator, there are roughly two types: a method of folding the electrode of the vibrator and a method of conducting from the horn without folding the electrode, but here, a method of conducting from the horn. Described.

  However, the vibration block 4 is used for each energy conversion process, the adhesive surface between the vibrator 1 and the horn 3, and further prevention of disconnection of the power supply lead wire of the vibrator 1, vibration prevention of the housing 8, and waterproofing of the vibration block 4. For this reason, in many cases, a part of the vibration block 4 is protected with silicon rubber or the like, and an indefinite amount of ultrasonic vibration energy is inevitably lost. Therefore, the present invention uses the fact that the efficiency of the vibration block 4 and the resonance impedance value of the vibration block 4 are highly correlated to derive the efficiency of each vibration block.

  FIG. 3 shows the configuration of the drive circuit 7 of the ultrasonic generator 10 according to the present embodiment. The drive circuit 7 includes an ultrasonic output control unit 11 as a drive circuit body, an efficiency deriving unit 12, and a correlation equation storage unit 13. The efficiency deriving unit 12 measures the impedance value or current value at the resonance frequency of the vibration block 4 and derives the electric-acoustic energy conversion efficiency of the vibration block 4. That is, the efficiency deriving unit 12 substitutes the resonance impedance value measured for each actual vibration block into the correlation equation between the impedance value and the efficiency of the correlation equation storage unit 13 obtained and stored for a plurality of vibration blocks in advance. Thus, the efficiency of each vibration block 4 can be derived.

  4 shows a procedure for measuring the efficiency in the efficiency deriving unit 12 of the drive circuit 7, FIG. 5 shows a voltage-current waveform in the vibration block at that time, and FIG. 6 shows a resonance impedance-efficiency correlation graph obtained in advance. Indicates. How to obtain the correlation equation between the impedance value of the vibration block and the efficiency will be described later. As a preferable method for measuring the impedance value in the efficiency deriving unit 12, as shown in FIG. 5, a constant voltage of about 1 Vp-p is input in a narrow frequency range near the frequency for driving the ultrasonic generator (# 1). ), The impedance value or the current value is measured by detecting the value of the current that flows (# 2, # 3). Of course, there are a wide variety of methods for measuring the impedance value and the current value, such as varying the voltage value according to the frequency or detecting a voltage for passing a constant current.

  Here, it is desirable to set a narrow range of the target resonance frequency ± 10% so that the resonance range and the anti-resonance point existing in the range each have one frequency. Since the lowest impedance value can be selected, the resonance impedance or the current value at the resonance point can be accurately measured.

  By substituting the resonance impedance thus obtained into a correlation graph (correlation equation) obtained in advance as shown in FIG. 6, it is possible to derive the energy conversion efficiency of the vibration block (# 4, # 5). As a result, it is possible to derive a quantity that is difficult to measure, such as an acoustic output or a calorific value, from the value of the electrical input.

  Next, FIG. 7 is an explanatory diagram for calculating a resonance point. Here, the impedance value or current value at the resonance frequency is assumed (calculated) from the measurement of the impedance value or current value around the resonance frequency. The impedance value at the resonance frequency is usually a small value of about several Ω. Therefore, when measuring an impedance value or a current value, even with a minute voltage of about 1 V, high electric power may be applied to the vibration block, which causes damage to the vibrator or failure. Therefore, by using the fact that the difference between the resonance frequency and the anti-resonance frequency is always about the same for vibration blocks with the same configuration, the resonance impedance value or current value is calculated from the slope of the impedance characteristic between the resonance frequency and the anti-resonance frequency. Can be sought.

  As the method, within a certain frequency range, the minimum impedance value or the maximum current value is determined in advance, and only the frequency above the impedance is measured. From this, the characteristic between the resonance frequency and the anti-resonance frequency is obtained, and the resonance impedance is assumed from the inclination. Thereby, the electric energy applied to the vibration block at the time of impedance value measurement can be limited, and the efficiency can be derived safely.

  FIGS. 8A and 8B show a state in which the electrical input to the vibration block is controlled so as to obtain a desired ultrasonic output based on the derived efficiency. The drive circuit in the apparatus is provided with an efficiency deriving unit (12 in FIG. 3) that can derive the efficiency of the vibration block from the value of the resonance impedance or current. The derived efficiency is used to control the ultrasonic output. Use. Here, in the ultrasonic generator, a desired ultrasonic output is obtained by inputting different electric power depending on the ultrasonic energy transmission loss of each vibration block.

  For example, in order to realize a desired ultrasonic output of 3 W, an electric input of 5 W is required for a vibration block with an efficiency of 60% as shown in FIG. 8A, while FIG. ), An electrical input of 3.75 W is required for a vibration block with an efficiency of 80%, and it is necessary to control the electrical input according to each vibration block. Therefore, the electric input to the vibration block is controlled by the value of the energy conversion efficiency previously derived from the impedance frequency characteristic as described above. As a result, it is possible to always obtain a desired ultrasonic output corresponding to control for each vibration block and vibration block deterioration and change.

  Hereinafter, a derivation method according to another embodiment of the correlation diagram acquired in advance will be described with reference to FIGS. 9 and 10. From the dynamic admittance diagram of the vibration block, a correlation equation between the resonance impedance and the efficiency can be obtained. It is also described in the literature that the electrical-acoustic conversion efficiency can be theoretically calculated by taking the ratio of the no-load dynamic admittance and the loaded dynamic admittance near the resonance frequency as the property of the piezoelectric vibrator of the vibration block. Yes.

  By measuring each admittance of the vibration block alone, a dynamic admittance diagram can be obtained and the electro-acoustic conversion efficiency of the vibration block can be obtained. Thus, impedance measurement data as shown in FIG. 11 is obtained for the vibration block, and by acquiring and accumulating a large number of data with such a large number of samples having the same configuration, a correlation diagram of the energy conversion efficiency with respect to the resonance impedance. (FIG. 6 above) can be created. The correlation formula based on this correlation diagram is stored in the efficiency deriving unit of the drive circuit.

  By using this correlation equation, if the vibration blocks can be regarded as having the same configuration, the efficiency can be calculated by substituting the resonance impedance value of each vibration block. Thus, by obtaining the resonance impedance value of the vibration block, the efficiency of the vibration block can be derived.

  FIG. 12 is an explanatory diagram for deriving the efficiency based on the calorimetric measurement of the vibration block. The efficiency in the correlation equation between the resonance impedance and the efficiency can also be calculated by a value obtained from the calorimetric measurement value of the ultrasonic output with respect to the electric input of the vibration block. The temperature measurement probe 31 of the temperature measuring device 30 is brought into contact with the driving vibration block 4 and the amount of heat generated is measured. The efficiency of each vibration block having the same configuration is calculated from this heat generation amount, and a correlation diagram as shown in FIG. 11 described above can be created from this and the resonance impedance of each vibration block alone. Preferably, it is desirable to obtain from the temperature rise after a certain time in the usage state of each vibration block.

  By using this correlation equation, if the configuration of the vibration block can be regarded as the same, the amount of heat generated and the efficiency of the vibration block can be calculated by substituting the resonance impedance value of each vibration block. Thus, by obtaining the resonance impedance value of the vibration block, it is possible to derive the heat generation amount and efficiency of the vibration block relatively easily.

  FIG. 13 is an explanatory diagram in the case of deriving the efficiency based on the mechanical measurement value of the ultrasonic output with respect to the electric input of the vibration block. An apparatus or method for dynamically measuring the sound pressure of an ultrasonic wave under load with a balance or the like is also described in the literature. This type of mechanical measurement device 35 drives the vibration block 4 and calculates the efficiency from the acoustic output corresponding to the electrical input at that time. A correlation diagram as shown in FIG. 11 described above can be created from the resonance impedance of each vibration block having the same configuration and the efficiency calculated from the mechanical measurement.

  By using the correlation equation shown in this correlation diagram, if the configuration of the vibration block can be regarded as the same, the efficiency of the vibration block can be calculated by substituting the resonance impedance value of each vibration block. it can. Thereby, by obtaining the resonance impedance value of the vibration block, it is possible to easily derive the efficiency of the vibration block.

  FIG. 14 shows a case where the ultrasonic generator is implemented in a thermal ultrasonic cosmetic device. Similarly to the above, this thermal ultrasonic cosmetic device is also provided with an efficiency deriving unit in the drive circuit. The derived efficiency is used to control the heat generation of the vibration block 4. The thermal ultrasonic cosmetic device uses a thermal effect separately from the ultrasonic treatment, and a thermal heater 40 is attached to the vibration block 4. A thermal ultrasonic humidifier may be provided. By driving the vibration block 4 and the thermal heater 40, a synergistic effect of sonic wave / thermal massage by ultrasonic vibration and heat is obtained. If the heat generated by the vibration block due to the energy transmission loss of ultrasonic waves is used, it is not necessary to provide another mechanism for heat generation such as the thermal heater 40.

  FIG. 15 is an explanatory diagram of a drive control method in a thermal ultrasonic cosmetic device that uses both the ultrasonic treatment and the thermal effect as described above. The energy conversion efficiency is obtained by substituting the resonance impedance value measured in each vibration block 4 into the correlation equation of the efficiency deriving unit obtained in advance, and the amount of heat generated in the vibration block 4 is controlled based on this energy conversion efficiency. be able to. For example, in order to realize a desired heat generation of 2 W, if the efficiency of the vibration block is calculated in advance and calculated as 60%, the heat generation amount becomes 40%, and the electric input is set to 5 W, thereby generating 2 W of heat. Can be realized. As a result, not only the effect of ultrasonic waves but also a synergistic effect with heat can be obtained, and the amount of generated heat can also be controlled.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made without departing from the spirit of the invention.

The block diagram of the ultrasonic generator to which this invention is applied. The block diagram of the vibration block of the apparatus. 1 shows a configuration of a drive circuit of an ultrasonic generator according to the present embodiment. The flowchart which shows the procedure which measures the efficiency in the efficiency derivation | leading-out part of a drive circuit. The figure which shows the voltage current waveform etc. in the vibration block at the time of efficiency measurement. The figure which shows the resonance impedance-efficiency correlation graph calculated | required previously. Explanatory drawing in the case of calculating a resonance point. The figure which shows a mode that the electrical input to a vibration block is controlled so that a desired ultrasonic output is obtained based on the derived | led-out efficiency. The figure explaining the derivation | leading-out method of the correlation diagram based on embodiment different from the above. The figure which shows the actual measurement data by the same as the above. The figure which shows the impedance measurement data by the method same as the above. Explanatory drawing when efficiency is derived | led-out based on the calorie | heat amount measurement of a vibration block. Explanatory drawing when efficiency is derived | led-out based on the mechanical measurement value of the ultrasonic output with respect to the electrical input of a vibration block. The figure at the time of implementing an ultrasonic generator in a thermal ultrasonic cosmetic device. Explanatory drawing of the drive control method in a thermal ultrasonic cosmetic device same as the above. The figure explaining the structure and operation | movement of the conventional ultrasonic generator. The figure which shows the energy transmission flow in an ultrasonic transmission process. The block diagram of an example of the vibration block in the conventional ultrasonic generator. The block diagram of the other example of the vibration block. The internal block diagram of the vibration block in the conventional ultrasonic generator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibrator 3 Horn 4 Vibrating block 7 Drive circuit 10 Ultrasonic generator 11 Ultrasonic output control part 12 Efficiency derivation part 13 Correlation type | formula memory | storage part

Claims (5)

An ultrasonic vibration block (referred to as a vibration block) composed of a vibrator that generates ultrasonic vibration, and a horn that is bonded to the vibrator and transmits ultrasonic waves to an object to be processed from an ultrasonic radiation surface of an arbitrary shape; In an ultrasonic generator provided with a drive circuit for driving these,
The drive circuit has an efficiency deriving unit for deriving the efficiency of the vibration block from the impedance or current value at the resonance frequency of the vibration block, and based on the efficiency derived by the efficiency deriving unit, a desired super An ultrasonic generator characterized by controlling an electric input to the vibration block so as to obtain a sound wave output.   2. The ultrasonic generator according to claim 1, wherein the efficiency deriving unit calculates efficiency based on data obtained from a dynamic admittance diagram of the vibration block obtained in advance.   2. The ultrasonic generation according to claim 1, wherein the efficiency deriving unit calculates efficiency based on data obtained from a calorimetric measurement value of ultrasonic output with respect to electrical input of the vibration block obtained in advance. apparatus.   2. The ultrasonic generation according to claim 1, wherein the efficiency deriving unit calculates efficiency based on data obtained from a mechanical measurement value of ultrasonic output with respect to the electrical input of the vibration block obtained in advance. apparatus.   2. The ultrasonic generator according to claim 1, wherein the drive circuit controls a heat generation amount lost as heat generation in the vibration block based on the efficiency calculated by the efficiency deriving unit.

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