JP2008155115A - Drive device of piezoelectric vibrator and ultrasonic cosmetic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device of a piezoelectric vibrator easily settable to a desired drive frequency and an ultrasonic hair treatment device. <P>SOLUTION: The drive device of the piezoelectric oscillator of the present invention is provided with: a VCO114 with oscillation frequency controlled according to a voltage value of control voltage; a fixed frequency divider 115 dividing output signals outputted from the VCO114 with a fixed first dividing ratio and outputting them as divided signals; a reference oscillation part 111A generating first reference signals; a phase comparator 112 outputting error signals according to the difference of the phase of the divided signals and the phase of the first reference signals; and an LPF113 filtering the error signals and outputting them as the control voltage. The reference oscillation part 111A is provided with an oscillator 1111 generating second reference signals; a variable divider 1112 dividing the second reference signals with a variable second dividing ratio and outputting them as the first reference signals; and a dividing control part 1113 controlling the variable frequency divider 1112 so as to divide the second reference signals of the oscillator 1111 with this second dividing ratio, upon receiving setting of the second dividing ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibrator driving device for driving a piezoelectric vibrator by a PLL circuit, and an ultrasonic facial device using the piezoelectric vibrator driving device.

  In recent years, ultrasonic waves have been applied to various fields such as agent penetration promotion, beauty, atomization, emulsification, dispersion, stirring, washing, bonding, and processing due to their properties. This ultrasonic wave is generated by a piezoelectric vibrator having a structure in which a piezoelectric material such as PZT or quartz is sandwiched between electrodes, which converts electrical vibration from the driving device into ultrasonic mechanical vibration. This piezoelectric vibrator driving method includes a self-excited oscillation method in which an oscillation circuit is adjusted so that the piezoelectric vibrator vibrates at a target driving frequency by feeding back the frequency of the piezoelectric vibrator to the oscillation circuit, and a piezoelectric vibrator. There is a separately-excited oscillation method in which an oscillation circuit is set in advance such that the oscillation circuit vibrates at a target drive frequency. A PLL (phase locked loop) circuit is known as an example of this separately excited oscillation circuit (see, for example, Patent Document 1).

In paragraph 38 of Patent Document 1, “PLL circuit has a known configuration including, for example, a programmable frequency divider, a phase comparator, a VCO (Voltage Controlled Oscillator), a low-pass filter, and the like. The output voltage is converted into a DC signal by a low-pass filter and applied to the VCO so that the oscillation frequency can be varied. "
JP 2002-345915 A

  By the way, when the piezoelectric vibrator is actually driven at a desired driving frequency, even if the oscillation frequency of the PLL circuit is designed according to the desired driving frequency, the elements constituting the piezoelectric vibrator and the PLL circuit. The piezoelectric vibrator is not necessarily driven at the desired drive frequency due to product variations or aging, and the oscillation frequency of the PLL circuit needs to be adjusted.

  On the other hand, the above-mentioned patent document 1 only has the above-mentioned description, and only suggests that the oscillation frequency of the PLL circuit can be adjusted by adjusting the division ratio of the programmable frequency divider. Yes, and others are not described or suggested.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a piezoelectric vibrator driving device that can be easily set to a desired driving frequency. An object of the present invention is to provide an ultrasonic hair treatment apparatus using such a piezoelectric vibrator driving apparatus.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, according to an aspect of the present invention, in the piezoelectric vibrator driving apparatus for driving the piezoelectric vibrator by the PLL circuit, the PLL circuit has a voltage control in which an oscillation frequency is controlled according to a voltage value of a control voltage. An oscillator, a first frequency divider that divides the output signal output from the voltage-controlled oscillator by a fixed first division ratio, and outputs the divided signal, and a reference oscillation unit that generates a first reference signal; A phase comparator that outputs an error signal corresponding to a difference between a phase of the frequency-divided signal output from the first frequency divider and a phase of the first reference signal output from the reference oscillation unit; A low-pass filter that filters the error signal output from the phase comparator and outputs the error signal as the control voltage, wherein the reference oscillation unit generates an second reference signal, and the second reference signal of the oscillator is variable. Divide by the second division ratio The second frequency divider that outputs the first reference signal and the setting of the second frequency division ratio are received, and the second reference signal of the oscillator is divided by the received second frequency division ratio. And a frequency division control unit for controlling the second frequency divider.

  In the piezoelectric vibrator driving apparatus having such a configuration, the first frequency divider that feeds back the output signal of the voltage controlled oscillator in the PLL circuit to the phase comparator has a circuit configuration in which the frequency division ratio is fixed at the first frequency division ratio. The second frequency divider in the reference oscillation unit that generates the first reference signal of the PLL circuit has a circuit configuration with a variable frequency division ratio. For this reason, when the drive frequency of the piezoelectric vibrator is set to a desired frequency, only the second frequency division ratio is compared with the case where the first and second frequency dividers have a variable frequency division circuit configuration. Therefore, the desired drive frequency can be easily set.

  In the above-described piezoelectric vibrator driving device, the reference oscillation unit receives and stores the setting of the second frequency division ratio from an external setting device, and the frequency division control is performed on the stored second frequency division ratio. And a storage unit for outputting to the storage unit.

  The piezoelectric vibrator driving apparatus having such a configuration changes the second frequency dividing ratio stored in the storage unit from an external setting device, thereby setting the second frequency dividing ratio so as to drive at a desired driving frequency. It can be set and can be easily reset.

  The above-described piezoelectric vibrator driving device further includes the piezoelectric vibrator.

  The piezoelectric vibrator driving apparatus having such a configuration is provided with a piezoelectric vibrator driving apparatus including a piezoelectric vibrator, and the second frequency division ratio according to the characteristics of the piezoelectric vibrator can be selected.

  In another aspect of the present invention, a piezoelectric vibrator that generates an ultrasonic wave, a piezoelectric vibrator driving device that drives the piezoelectric vibrator, and the piezoelectric vibrator is bonded to one surface. A transmission member for transmitting the ultrasonic wave from the piezoelectric vibrator to the radiation surface of the other surface, and an ultrasonic facial device that causes the ultrasonic wave radiated from the radiation surface to act on the skin. Is a drive device for the piezoelectric vibrator described above.

  In the ultrasonic facial device having such a configuration, when the drive frequency of the piezoelectric vibrator is set to a desired frequency, it is only necessary to adjust the second frequency division ratio, so that it is easily set to the desired drive frequency. Can do. For this reason, since the ultrasonic facial device radiates ultrasonic waves having a predetermined frequency from the radiation surface, the ultrasonic waves can be effectively applied to the skin.

  The piezoelectric vibrator driving apparatus according to the present invention can easily set the driving frequency of the piezoelectric vibrator to a desired frequency. The ultrasonic facial device according to the present invention can easily set the drive frequency of the piezoelectric vibrator to a desired frequency and radiates ultrasonic waves of a predetermined frequency from the radiation surface, so that the skin is effectively applied to the skin. Ultrasound can be applied.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

  FIG. 1 is a diagram illustrating an ultrasonic facial beauty apparatus according to an embodiment. 1A is a perspective view, FIG. 1B is a front view, FIG. 1C is a side view, and FIG. 1D is FIG. 1B. It is sectional drawing in AA. FIG. 2 is a block diagram illustrating a configuration of the ultrasonic facial beauty apparatus according to the embodiment. FIG. 3 is a block diagram showing a configuration of an ultrasonic wave oscillating unit in the ultrasonic facial beauty apparatus shown in FIG. FIG. 4 is a diagram showing impedance characteristics of the head block shown in FIG. The horizontal axis in FIG. 4 is frequency, and the vertical axis is impedance expressed in Ω on a logarithmic scale.

  In FIG. 1, an ultrasonic facial beauty apparatus S is an apparatus for improving the skin condition by applying ultrasonic waves to skin such as a face. The ultrasonic facial beauty apparatus S includes a housing 1 that forms an outer shell thereof. The housing 1 is formed in a shape that can be gripped with one hand. For example, as shown in FIG. 1, the housing 1 is formed in a rod shape having a substantially elliptical cross section perpendicular to the longitudinal direction. An operation switch 2 for switching on and off the ultrasonic facial beauty device S is provided in a substantially central portion of the housing 1 so as to be able to project and retract. A head block HB is provided at the tip of the housing 1. An ultrasonic control block CB is accommodated in the housing 1.

  The head block HB is a member for applying ultrasonic waves to the skin, and includes, for example, a piezoelectric vibrator 21 and a head 22 as shown in FIG. The piezoelectric vibrator 21 converts electrical vibration from the ultrasonic control block CB into ultrasonic mechanical vibration, and is, for example, an ultrasonic vibrator having a structure in which a piezoelectric material such as PZT or quartz is sandwiched between electrodes. . The head 22 has a piezoelectric vibrator 21 bonded to one surface thereof and transmits ultrasonic mechanical vibration from the piezoelectric vibrator 21 to the radiation surface of the other surface, and is an example of a transmission member. The head 22 is, for example, a conductive metal member such as aluminum or a light alloy having a cylindrical shape with a short and high bottom, and the piezoelectric vibrator 21 is bonded to the inner bottom surface thereof with an adhesive in a highly conductive state. The outer bottom surface 22a is the radiation surface.

  The ultrasonic control block CB is an example of a piezoelectric vibrator driving device for driving the piezoelectric vibrator 21 by a PLL (phase locked loop) circuit, and an electric vibration for driving the piezoelectric vibrator 21. Is a circuit that generates Then, the ultrasonic control block CB generates this electric vibration according to the projecting and retracting operation of the operation switch 2, and outputs the generated electric vibration to the piezoelectric vibrator 21. The ultrasonic control block CB, for example, as shown in FIG. 2, for example, an ultrasonic oscillator 11A that generates an AC signal of a predetermined frequency such as a sine wave, and an AC signal generated by the ultrasonic oscillator 11A in advance. An amplifier unit 12 that amplifies at a predetermined amplification factor that is set and outputs the electric vibration to the piezoelectric vibrator 21 of the head block HB, and a power source unit 13 that supplies power to the amplifier unit 12 and the ultrasonic oscillation unit 11A. I have.

  The ultrasonic oscillating unit 11A includes a PLL circuit. For example, as shown in FIG. 3, the reference oscillating unit 111A, a phase comparator 112, and a low-pass filter (hereinafter abbreviated as “LPF”) 113 are used. And a voltage controlled oscillator (hereinafter abbreviated as “VCO”) 114 and a fixed frequency divider 115.

  The reference oscillation unit 111A is an oscillation circuit that generates a reference signal (first reference signal) of the PLL circuit, and outputs the generated first reference signal to the phase comparator 112. For example, the reference oscillation unit 111A includes an oscillator 1111, a variable frequency divider 1112, and a frequency division control unit 1113. The oscillator 1111 is a circuit that generates a reference signal (second reference signal) by oscillating a stable signal having a predetermined frequency, and outputs the second reference signal to the variable frequency divider 1112. The oscillator 1111 includes, for example, a crystal resonator and an inverter having a gain greater than 1. A crystal that stably oscillates at the natural frequency of the crystal resonator by returning the output of the inverter to the input via the crystal resonator. Such as an oscillator. The variable frequency divider 1112 divides the second reference signal output from the oscillator 1111 by a frequency division ratio (second frequency division ratio) m, and outputs the result as the first reference signal. The divide-by-2 ratio m can be changed. The variable frequency divider 1112 is an example of a first frequency divider. The frequency of the first reference signal is (frequency of the second reference signal) / m. The variable frequency divider 1112 outputs the first reference signal to the phase comparator 112 as an output signal of the reference oscillation unit 111A. The frequency division control unit 1113 receives the setting of the second frequency division ratio m, and controls the variable frequency divider 1112 so as to divide the second reference signal of the oscillator 1111 by the received second frequency division ratio m. Circuit.

  For example, the reference oscillation unit 111A includes individual components, and the second frequency division ratio m of the frequency division control unit 1113 is set by a dip switch or the like. Alternatively, the reference oscillation unit 111A is configured by a microcomputer, the variable frequency divider 1112 and the frequency division control unit 1113 are functionally realized on the microcomputer, and the variable frequency divider 1112 and the frequency division control unit 1113 are functionally implemented. In addition, the second frequency division ratio m of the frequency division control unit 1113 is set by a variable of the second frequency division ratio m in a program realized on the microcomputer.

  The phase comparator 112 compares the phase of the first reference signal output from the reference oscillation unit 111A with the phase of the first frequency division signal output from the fixed frequency divider 115, and an error signal corresponding to the phase difference. And an error signal corresponding to the phase difference is output to the low-pass filter 113.

  The low-pass filter 113 is a filter circuit that cuts off a signal having a frequency higher than a predetermined cut-off frequency set in advance and passes a signal below the cut-off frequency, and filters the error signal output from the phase comparator 112. The high frequency component mixed in the error signal of the phase comparator 112 is removed and output to the VCO 114 as a DC component control voltage. The cutoff frequency of the low-pass filter 113 is appropriately set according to the specifications of the ultrasonic oscillator 11A.

  The VCO 114 is an oscillator whose oscillation frequency is controlled according to the voltage value of the control voltage, and the output signal of the VCO 114 becomes the output signal (the electric vibration) of the ultrasonic oscillator 11A and also to the fixed frequency divider 115. Is output.

  The fixed frequency divider 115 is a circuit that divides the output signal output from the VCO 113 by a frequency division ratio (first frequency division ratio) n and outputs it as a frequency division signal. The first frequency division ratio n Is fixed. Fixed frequency divider 115 is an example of a first frequency divider. In order for the phase comparator 112 to be able to compare the phase of the first reference signal from the reference oscillation unit 111A and the phase of the frequency-divided signal from the fixed frequency divider 115, the first frequency division ratio n is an output of the VCO 113. The frequency of the signal is set so as to be the same order of frequency as the frequency of the first reference signal of the reference oscillation unit 111A, for example, approximately the same frequency.

  More specifically, for example, in the case where the piezoelectric vibrator 21 bonded to the head 22 is set to be driven at 1.05 MHz, the ultrasonic oscillator 11A is set to 4 as the first reference signal. When a 1017 kHz signal is output, the first frequency division ratio n is set to 1.05 MHz / 4.1017 kHz = 256. Then, the fixed frequency divider 115 in which the first frequency division ratio n is fixed at 256 is created.

  In the ultrasonic facial beauty device S having such a configuration, when the operation switch 2 is operated and turned on, the ultrasonic control block CB operates, and the electric vibration from the ultrasonic control block CB is applied to the piezoelectric vibrator 21 of the head block HB. Supplied to. The piezoelectric vibrator 21 converts this electric vibration into mechanical vibration. As a result, the head 22 bonded to the piezoelectric vibrator 21 is mechanically vibrated, and ultrasonic waves are emitted from the radiation surface 22a. Here, when the skin is in direct contact with the radiation surface 22a of the head 22 or indirectly through an agent such as a treatment liquid, ultrasonic waves act on the skin and the skin state is improved.

  In the ultrasonic control block CB, when electric vibration is supplied to the piezoelectric vibrator 21 of the head block HB, first, the output signal of the VCO 114 is frequency-divided by the fixed frequency divider 115 at the first frequency division ratio n to be a predetermined value. The frequency is converted and output to the phase comparator 112. In the phase comparator 112, the phase of the frequency-divided signal from the fixed frequency divider 115 and the first reference signal from the reference oscillation unit 11A are compared, and an error signal corresponding to the phase difference is output to the LPF 113. The first reference signal is generated by dividing the second reference signal output from the oscillator 111 by the variable frequency divider 1112 with the second frequency division ratio m under the control of the frequency division control unit 1113. The LPF 113 removes the high frequency component mixed in the error signal, and outputs the control voltage of the direct current component to the VCO 114. Then, the VCO 114 changes the oscillation frequency f in accordance with the control voltage so that the frequency of the divided signal and the frequency of the first reference signal match. By operating in this way, the ultrasonic oscillator 11A stably oscillates at a frequency f that is n times the frequency of the first reference signal, and supplies electrical vibration to the piezoelectric vibrator 21 of the head block HB.

  Here, the drive frequency fd of the piezoelectric vibrator 21 is determined as follows. The impedance characteristic of the piezoelectric vibrator 21 bonded to the head 22 is, for example, in an unloaded state in which an object that transmits ultrasonic mechanical vibration, for example, the skin is not in contact with the radiation surface 22a of the head 22, is shown in FIG. As indicated by the solid line CNL in FIG. 4, as the frequency f increases, the impedance Z gradually decreases to become the minimum Zr1 at the frequency fr, then increases to be approximately proportional to become the maximum Za1 at the frequency fa, and gradually gradually again. The profile becomes smaller. In a load state in which an object transmitting ultrasonic mechanical vibration is in contact with the radiation surface 22a, the impedance characteristic is substantially the same as the impedance characteristic CNL in the no-load state, as indicated by a broken line CL in FIG. Although it is a profile, the minimum impedance Zr2 in the impedance characteristic CL in the loaded state is larger than the minimum impedance Zr1 in the impedance characteristic CNL in the no-load state, and the maximum impedance Za2 in the impedance characteristic CL in the loaded state is the no-load state The impedance characteristic CNL is smaller than the maximum impedance Za1.

  The frequency fr is the resonance frequency, the frequency fa is the anti-resonance frequency, and the drive frequency fd of the piezoelectric vibrator 21 is determined between the resonance frequency fr and the anti-resonance frequency fa (oscillation range RR).

  Then, in order to reduce the supply power in the no-load state, the drive frequency fd of the piezoelectric vibrator 21 is determined so that the impedance Z becomes high when there is no load. That is, the drive frequency fd of the piezoelectric vibrator 21 is determined between the resonance frequency fr and the antiresonance frequency fa and close to the antiresonance frequency fa.

  In addition, when the ultrasonic control block CB is configured so as to detect whether it is in a no-load state or a load state by the impedance Z of the piezoelectric vibrator 21, so that it can be detected more reliably. The drive frequency fd of the piezoelectric vibrator 21 is determined so that the difference between the impedance Z in the no load state and the impedance Z in the load state becomes large.

  Therefore, the drive frequency fd of the piezoelectric vibrator 21 is closer to the anti-resonance frequency fa from the frequency fm at the intersection point where the impedance characteristic CNL in the no-load state and the impedance characteristic CL in the load state intersect to the anti-resonance frequency fa. Determined to frequency. For example, as shown in FIG. 4, the drive frequency fd of the piezoelectric vibrator 21 is determined, and the impedance Z becomes the impedance Zd in the no-load state and becomes the impedance Zd ′ (<Zd) in the load state.

  When the drive frequency fd of the piezoelectric vibrator 21 is thus determined, the power consumption in the no-load state is reduced, and whether the load is in the no-load state or the load state is detected without providing a separate sensor. Therefore, the device is downsized.

  Further, the second frequency division ratio m of the variable frequency divider 1112 is determined based on the oscillation frequency of the oscillator 1111 so that the reference oscillation unit 111A outputs a first reference signal having a predetermined frequency, and the frequency division control unit 1113. Is set to the second frequency division ratio m. For example, in the above example, when the frequency of the first reference signal is 4.1017 kHz and the frequency of the second reference signal output from the oscillator 1111 is 80 MHz, the second frequency division ratio m is 80 MHz / 4.1017 = 19504 is determined, and is set in the frequency division control unit 1113.

  Here, in an actual product, the piezoelectric vibrator 21 is not necessarily driven at the determined drive frequency fd due to product variations of the elements constituting the piezoelectric vibrator 21 or the PLL circuit, or aging, and the oscillation in the PLL circuit. Frequency adjustment is required. In such a case, the reference oscillation unit 111A of the ultrasonic facial device S according to the present embodiment changes the second frequency division ratio m set in the frequency division control unit 1113, thereby changing the variable frequency divider 1112. The second frequency division ratio m can be easily changed, and the piezoelectric vibrator 21 can be driven at the determined drive frequency fd. For example, in the case of the above example, the resolution is 80 MHz / 19504 × 256 = 1.0500041 MHz in the case of the second division ratio m = 19504, while the resolution is 80 MHz / in the case of the second division ratio m = 19505. Since 19504 × 256 = 1.049987 MHz, the frequency is 53 Hz, and the drive frequency fd of the piezoelectric vibrator 21 can be adjusted in increments of 53 Hz.

  In the ultrasonic oscillator 11A of the ultrasonic facial device S according to this embodiment, the fixed frequency divider 115 that feeds back the output signal of the VCO 114 to the phase comparator 112 has a frequency division ratio of the first frequency division ratio n. Only the variable frequency divider 1112 that is fixed and divides the second reference signal of the oscillator 1111 has a variable frequency dividing ratio. Therefore, when both the frequency divider that feeds back the output signal of the VCO 114 to the phase comparator 112 and the frequency divider that divides the second reference signal of the oscillator 1111 are configured to be able to change the frequency division ratio. In comparison, the ultrasonic beauty apparatus S and the ultrasonic oscillator 11A according to the present embodiment can adjust the drive frequency fd of the piezoelectric vibrator 21 with one parameter called the second division ratio m. Therefore, the drive frequency fd of the piezoelectric vibrator 21 can be easily adjusted to a predetermined frequency. For this reason, complication of the circuit configuration is avoided, the circuit configuration is simplified, and element variation is reduced, so that the accuracy of the drive frequency fd of the piezoelectric vibrator 21 is further improved. Furthermore, in the ultrasonic facial device S in which the drive frequency fd of the piezoelectric vibrator 21 is determined as described above, the ultrasonic oscillator 11A is suitable because precise control is required.

  FIG. 5 is a block diagram showing another configuration of the ultrasonic wave oscillating unit in the ultrasonic facial beauty apparatus shown in FIG.

  In the above-described embodiment, the ultrasonic facial device S may be configured to include the ultrasonic oscillation unit 11B illustrated in FIG. 5 instead of the ultrasonic oscillation unit 11A. The ultrasonic oscillator 11B shown in FIG. 5 is further replaced with an oscillator 1111, a variable frequency divider 1112 and a frequency divider controller 1113 in place of the reference oscillator 111A of the ultrasonic oscillator 11A shown in FIG. A reference oscillation unit 111B including a storage unit 1114 that receives and stores the setting of the second frequency division ratio m from the setting device T and outputs the stored second frequency division ratio m to the frequency division control unit 1113. Is done.

  The storage unit 1114 includes a rewritable nonvolatile storage element such as an EEPROM (Electrically Erasable Programmable Read Only Memory).

  In the ultrasonic facial device S having such a configuration, for example, the impedance of the piezoelectric vibrator 21 in the unloaded state in the ultrasonic facial device S by a commercially available impedance characteristic measuring device in a pre-commercial stage such as a manufacturing stage or a shipping stage. Characteristics (vibrator characteristics) are measured, the drive frequency fd of the piezoelectric vibrator 21 is determined based on the measured impedance characteristics, the second frequency division ratio m is determined so as to be the determined drive frequency fd, The determined second frequency division ratio m is stored in the storage unit 1114 by the setting device T. For example, when the storage unit 1114 includes an EEPROM, the setting device T includes a PROM writer.

  The drive frequency fd of the piezoelectric vibrator 21 is determined as described above. For example, among the frequencies from the intersection fm where the impedance characteristic CNL in the no-load state and the impedance characteristic CL in the load state intersect to the anti-resonance frequency fa, The frequency is determined by a shift amount Δf from the frequency fm of the intersection point to the antiresonance frequency fa. That is, fd = fm + Δf and 0 <Δf <fa−fm. The shift amount Δf is appropriately set according to the specifications of the ultrasonic oscillator 11B in consideration of the degree of power saving in the no-load state and the ease of detecting whether or not the load is in the no-load state. The

  The frequency fm at this intersection can be obtained by measuring the impedance characteristic CNL in the no-load state and the impedance characteristic CL in the loaded state with an impedance characteristic measuring device. The resonance frequency fr and the anti-resonance frequency fa in the no-load state are obtained. And the frequency fm of the intersection point are obtained by measuring a plurality of piezoelectric vibrators 21 bonded to the head 22 and performing statistical processing, and by using this relationship, piezoelectric vibration in an unloaded state is obtained. The resonance frequency fr and the antiresonance frequency fa may be obtained from the impedance characteristics of the child 21 to obtain the frequency fm at the intersection. As a result, the frequency fm of the intersection can be obtained in a shorter time.

  When the second frequency division ratio m is stored in the storage unit 1114, the frequency division control unit 1113 uses the second frequency division ratio m stored in the storage unit 1114, and uses the second frequency division ratio m. The variable frequency divider 1112 is controlled to divide the second reference signal of the oscillator 1111.

  Thus, the drive frequency fd of the piezoelectric vibrator 21 can be easily set in accordance with the characteristics of the piezoelectric vibrator 21 in each ultrasonic facial beauty device S. Since the ultrasonic facial device S emits ultrasonic waves of a predetermined frequency from the radiation surface 22a, the ultrasonic waves can be effectively applied to the skin.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Accordingly, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not limited to the scope of the claims. To be construed as inclusive.

It is a figure which shows the ultrasonic facial beauty apparatus in embodiment. It is a block diagram which shows the structure of the ultrasonic facial beauty apparatus in embodiment. It is a block diagram which shows the structure of the ultrasonic oscillation part in the ultrasonic facial beauty apparatus shown in FIG. It is a figure which shows the impedance characteristic of the head block shown in FIG. It is a block diagram which shows the other structure of the ultrasonic oscillation part in the ultrasonic facial beauty apparatus shown in FIG.

Explanation of symbols

S Ultrasonic Facial Device T Setting Device HB Head Block CB Ultrasonic Control Blocks 11A, 11B Ultrasonic Oscillator 21 Piezoelectric Vibrator 22 Heads 111A, 111B Reference Oscillator 112 Phase Comparator 113 Low Pass Filter 114 Voltage Control Oscillator 115 Fixed Frequency Dividing Unit 1111 oscillator 1112 variable frequency divider 1113 frequency division control unit 1114 storage unit

Claims (4)

In a piezoelectric vibrator driving apparatus for driving a piezoelectric vibrator by a PLL circuit,
The PLL circuit includes:
A voltage controlled oscillator in which the oscillation frequency is controlled according to the voltage value of the control voltage;
A first divider that divides the output signal output from the voltage controlled oscillator by a fixed first dividing ratio and outputs the divided signal as a divided signal;
A reference oscillation unit for generating a first reference signal;
A phase comparator that outputs an error signal according to a difference between a phase of the frequency-divided signal output from the first frequency divider and a phase of the first reference signal output from the reference oscillation unit;
A low-pass filter that filters the error signal output from the phase comparator and outputs it as the control voltage;
The reference oscillation unit is
An oscillator for generating a second reference signal;
A second frequency divider that divides the second reference signal of the oscillator by a variable second frequency division ratio and outputs the first reference signal;
A frequency division control unit that receives the setting of the second frequency division ratio and controls the second frequency divider so as to divide the second reference signal of the oscillator by the received second frequency division ratio; A piezoelectric vibrator driving device characterized by the above. The reference oscillation unit further includes a storage unit that receives and stores the setting of the second frequency division ratio from an external setting device, and outputs the stored second frequency division ratio to the frequency division control unit. The piezoelectric vibrator drive device according to claim 1. The piezoelectric vibrator driving apparatus according to claim 1, further comprising: the piezoelectric vibrator. A piezoelectric vibrator that generates ultrasonic waves, a piezoelectric vibrator driving device for driving the piezoelectric vibrator, the piezoelectric vibrator is bonded to one surface, and the ultrasonic waves from the piezoelectric vibrator are transmitted to the other surface. An ultrasonic facial device that includes a transmission member that transmits to a radiation surface, and that acts on the skin with ultrasonic waves emitted from the radiation surface;
The ultrasonic facial device according to claim 1, wherein the piezoelectric vibrator driving device is the piezoelectric vibrator driving device according to claim 1.

Images