KR200332097Y1 - Display device of a skin care apparatus having led display function - Google Patents

Abstract

The present invention relates to a display device of a portable skin care device, connected in parallel between the first input and output terminals (RB2; RD0) and the second input and output terminals (RB3; RD1) of the control device (CPU), but connected in opposite directions First and second LEDs (D7, D6 in FIG. 3; D11, D12 in FIG. 11); Third and fourth LEDs (D8 in FIG. 3, respectively) connected in parallel between the second input / output terminals RB3 and RD1 and the third input / output terminals RC0 and RD2 of the control device CPU, and connected in opposite directions. D9, D16, D17 in Fig. 11); The fifth and sixth LEDs (D13 of FIG. 3, respectively) connected in parallel between the third input / output terminals RC0 and RD2 and the fourth input / output terminals RC1 and RC6 of the control device CPU are connected in opposite directions. D11 (D21, D22 in FIG. 11); And a seventh LED (D14 in FIG. 3; D15 in FIG. 11) connected between the first input / output terminal RB2 (RC6) and the fourth input / output terminal RC1; RC5 of the control device CPU. Each LED is independently turned on / off by a signal value for each input / output terminal from the control device, and it is possible to emit a plurality of LEDs even with a small number of connection terminals.

Description

DISPLAY DEVICE OF A SKIN CARE APPARATUS HAVING LED DISPLAY FUNCTION}

The present invention relates to a display device in a skin care device such as an ultrasonic vibrator, and more particularly to a display device with a minimum number of connection pins.

In conventional portable skin care devices, display devices using LEDs have one CPU terminal to drive one LED, so that when the skin care device has various stages or functions, these functions are used by using LEDs. In order to indicate, several connection terminals were required. This immediately became a major factor in increasing the cost of the CPU.

The present invention is to solve the conventional problems as described above, by using a small number of CPU connection terminals, by turning on / off several LEDs can also be used as a CPU having a small number of connection pins to reduce the cost of the CPU eventually It is possible to provide a display device for a skin care device having an LED display function with a minimum number of connection pins.

1 is a block diagram of the ultrasonic skin care device according to the present invention.

Figure 2 is a detailed circuit diagram of the power supply and switch of the skin care device according to the present invention.

Figure 3 is a detailed circuit diagram of the output of the skin care device according to the present invention.

Figure 4 is a detailed circuit diagram of the temperature sensing unit of the skin care device according to the present invention.

5 is a detailed circuit diagram of the ultrasonic drive unit of the skin care device according to the present invention.

Figure 6 shows a pulse waveform for the ultrasonic drive of the skin care device according to the present invention of FIG.

7 shows a pulse waveform for voltage control of the skin care device according to the present invention of FIG.

8 is a flowchart showing a control flow for stable voltage control according to the present invention.

9 is a block diagram of an ultrasonic ion skin care device according to a second embodiment of the present invention.

10 is a detailed circuit diagram of a power supply and a switch of the ultrasonic ion skin care device according to the second embodiment of the present invention.

11 is a detailed circuit diagram of the display unit of the ultrasonic ion skin care device according to a second embodiment of the present invention.

12 is a detailed circuit diagram of the laser and the ultrasonic drive unit of the ultrasonic ion skin care device according to a second embodiment of the present invention.

13 is a detailed circuit diagram of a galvanic driving unit and a body detecting unit of the ultrasonic ion skin care device according to the second embodiment of the present invention.

14 is an external view of the instrument panel of the ultrasonic ion skin care device according to the second embodiment of the present invention.

FIG. 15 shows a voltage waveform applied to the galvanic driver of FIG. 13.

<Description of the symbols for the main parts of the drawings>

1: Battery 2, 102: CPU

10: voltage measuring unit 20: DC-DC converter

30; Switch unit 31: the first switch unit

32: second switch 40: display unit

50: ultrasonic drive unit 51: voltage amplifier

52: vibrator 53: resonator

54: oscillation unit 60: body detection unit

61: current sensing unit 62: amplifying unit

70; Temperature Sensing Unit 71: First Temperature Sensing Unit

72: second temperature detection unit 80: signal sound generating unit

90: auxiliary circuit section 91: reference voltage generator

92 reset unit

101: DC adapter 120: DC-DC converter section

130; Switch unit 140: display unit

150: ultrasonic drive unit 151: galvanic drive unit

153: laser drive unit 160: body detection unit

190: reset unit

In order to achieve the above object of the present invention, the display device of the skin care device having the LED display function with the minimum number of connection pins according to the first aspect of the present invention, the first input and output terminals (RB2; RD0) of the control unit (CPU) and First and second LEDs (D7 and D6 in FIG. 3; D11 and D12 in FIG. 11) connected in parallel between the second input / output terminals RB3 and RD1, and connected in opposite directions; Third and fourth LEDs (D8 in FIG. 3, respectively) connected in parallel between the second input / output terminals RB3 and RD1 and the third input / output terminals RC0 and RD2 of the control device CPU, and connected in opposite directions. D9, D16, D17 in Fig. 11); The fifth and sixth LEDs (D13 of FIG. 3, respectively) connected in parallel between the third input / output terminals RC0 and RD2 and the fourth input / output terminals RC1 and RC6 of the control device CPU are connected in opposite directions. D11 (D21, D22 in FIG. 11); And a seventh LED (D14 in FIG. 3; D15 in FIG. 11) connected between the first input / output terminal RB2 (RC6) and the fourth input / output terminal RC1; RC5 of the control device CPU. Each LED is independently turned on / off by a signal value for each input / output terminal from the control device.

Preferably, the first to sixth LEDs are used to indicate the strength and mode operation, and the seventh LEDs may be used to indicate the use state of the skin care device.

Further, eighth and ninth LEDs (D25 and D26 in FIG. 11) connected in parallel between the fourth input / output terminal RC6 and the fifth input / output terminal RC5 of the control device CPU and connected in opposite directions. It may further include, preferably, the first to sixth LED is used to indicate the galvanic ion step and the ultrasonic mode operation, the seventh LED is used to indicate the state of use of the skin care device, The eighth and ninth LEDs may be used to indicate the intensity step.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention in detail.

1 is an overall block diagram of the ultrasonic skin care device according to the present invention, Figure 2 is a detailed circuit diagram of the power supply and switching unit of the skin care device according to the present invention, Figure 3 is a detailed circuit diagram of the output unit of the skin care device according to the present invention, Figure 4 is a detailed circuit diagram of the temperature sensing unit of the skin care device according to the present invention, Figure 5 is a detailed circuit diagram of the ultrasonic drive unit of the skin care device according to the present invention.

In addition, Figure 6 shows a pulse waveform for the ultrasonic drive of the skin care device according to the present invention of Figure 5, Figure 7 shows a pulse waveform for voltage control of the skin care device according to the present invention of FIG.

First, as shown in FIG. 1, the charging power of the battery is boosted by the DC-DC converter 20 to drive the CPU 2, which in turn drives an ultrasonic element to a multi-level level by a pulse width change. 50 and the body detecting unit 60 for detecting whether the user's body is in contact with the ultrasonic device, the temperature detecting unit 70 for detecting an overheating state of the device, the switch unit 30 of the power switch and the operation switch , The display unit 40 for displaying the operation state, the signal sound generation unit 80 and the other auxiliary circuit unit 90 for warning the abnormal operation state as a beep. Meanwhile, in order to precisely control the voltage and reduce power consumption, the battery voltage measuring unit 10 having a battery remaining amount and having a battery protection circuit is connected to the battery.

Now, referring to FIG. 2, the switch unit 30 of the first switch unit 31 and the second switch unit 32, the DC-DC converter unit 20, and the reference voltage generator 91 and the reset unit ( The power supply section including the auxiliary circuit section 90 of FIG. 92 will be described in more detail.

As for the input terminal of the 1st switch part 31, the charging terminals J1 and J2 and the battery terminal J3 connected to an external power supply are connected in parallel. Another battery terminal J4 is not required, but it is assumed that the pole of the battery terminal is changed.

When the power switch SW1 is 'on', the switch-in (SW_IN) signal is input to the analog input terminal AN5 of the CPU 2 through the second switch unit 32 to activate the CPU. Then, the CPU activates the first switch unit 31 through the analog output terminal AN7, and operates the photocoupler ISO1 through the resistor R16 to switch the FET D4 so that the battery power is supplied to the DC-DC converter. To (20).

In this case, the battery voltage is measured by the battery voltage measuring unit 10 including the divided resistors R1 and R35 and input to the analog input terminal AN1 of the CPU.

On the other hand, since portable beauty devices usually use a battery of a single input power supply (for example, 3.6V), in some cases, boosting the voltage to a high voltage (10-15V for an ultrasonic device and 20-30V for an ion introducer, for example) Although the process is essential, the DC-DC converter unit 20 for this purpose has previously used an expensive chip, but in the present invention, as shown in FIG. 2, the output voltage is adjusted by adjusting a frequency duty rate. Is achieved by the PWM control program of the switching element D3 and the CPU.

That is, when the switching signal is output from the PWM control terminal (terminal 10) of the CPU, the switching element D3 is turned on / off to control the pulse width, thereby making it possible to control the power of the output voltage. That is, when the user wants to use the beauty device, when turning on the power and facing the skin, when using the device to the body by the body detection unit 60 to be described later, by increasing the 'switch-on' time interval of the PWM control signal In this case, the power supply is stepped up to the target voltage during use. This is achieved by using a feedback control method, as shown in (a) of FIG. 7, so that problems of the related arts such as system down due to sudden voltage rise are solved. In addition, step down also eliminates the problems caused by sudden voltage drops, as shown in FIG. 7B, by gradually decreasing the pulse width. As a result, stable power management is possible.

In fact, VDD, the output voltage of DC-DC converter, can output 12-15V when using beauty equipment, and power consumption can be reduced by keeping power supply about 10V when not in use.

The divider resistors R2 and R3 sense the output voltage to sense the output voltage sensed by the analog input terminal AN2 to match the voltage of the CPU (eg, 3.3V).

A power management program of the CPU for implementing the above operation will be described with reference to FIG. 8 is a flowchart showing a control flow for stable voltage control according to the present invention.

First, as shown in FIG. 8, when the pulse width check program PWM_CHECK is started (S1), 'PWM OK FLAG' is checked to check whether PWM control operates by a desired set value (S2). If it works as you wish ('PWM OK FLAG' = 1), return to step S9 and continue. Otherwise, compare the PWM set point ('PWM_TARGET') with the actual PWM value ('PWM_PUF'). (S3), if the value is the same ('PWM_PUF'-'PWM_TARGET' = 0), the process returns to step S9 to continue, otherwise the PWM control steps S4 to S8 are performed.

First, it is examined whether the carry value is 0 (S4), in order to examine whether the duty ratio of the pulse width is larger than the set value. If the set value is smaller than the measured value, the PWM setting is performed (S5) and the PWM value actually applied is increased by a predetermined value to increase the duty ratio (S7). Conversely, if the set value is larger than the measured value, the PWM setting is performed (S6) and the PWM value actually applied is reduced by a predetermined value to reduce the duty ratio (S8).

After that, the process returns to the step S2 to continue the program.

On the other hand, the above-described programmed power adjustment method and apparatus, can also be used to adjust the output intensity of the beauty device. That is, if the user intentionally adjusts the output from 'weak' to 'strong' by adjusting the third switch (SW3), which is the intensity control switching, the analog input terminal AN5 accepts this to the PWM control terminal (pin 10). By applying a PWM pulse width adjustment signal, the duty ratio can be increased to allow the output to be 'strong'. For example, if you want to use the skin care device on the skin of sensitive areas such as the face, you need to weaken the output. On the contrary, if you want to use it on the hip or calf, it is better to increase the output.

The second switch SW2 of the second switch unit 32 is a mode switch for adjusting the step of the beauty device. As shown in FIG. 6, frequency conversion is performed on pulses of the output signal of the analog output terminal RA0 of the ultrasonic driver 50 of FIG. 5 to be described later so that an appropriate signal is output at each step according to each step. For example, the ultrasonic beauty device of the present invention is capable of adjusting the strength and intensity (H / L) of four stages according to the frequency conversion and two stages according to the voltage change.

On the other hand, by configuring as the second switch unit, it is possible to accept various voltages with one input port. Reference numeral 91 is a reference voltage generator, 92 is a reset unit, L1 is a reactor, C2 and C3 are capacitors, and D1 and D2 are anti-reversal diodes.

Now, with reference to Figure 5 will be described in detail with respect to the ultrasonic drive unit 50 is the core of the present invention.

Now, when the control signal oscillated at the appropriate frequency by the CPU as described above is output to the voltage amplifier 51 of the ultrasonic drive unit through the analog output terminal RA0, the voltage amplifiers R15, Q4, Q5, R8, R9, After the amplification at D10), it is input to the ultrasonic vibrator ULTRA1 which is a piezoelectric element of the vibrator 52 through the resonator 53. That is, when a pulse is applied to the vibrator, the free vibration is performed, and the power is well transmitted, so that resonance occurs well, thereby causing self-resonant oscillation to the transistor Q2 called a resonance tank. This causes the phase in the transformer T1 to be amplified from the zero potential to the + side, and is oscillated by the oscillation switching elements Q3 and Q6 of the oscillation unit 54, and again through the transformer T2 of the oscillator 52 again, an ultrasonic vibrator Power is applied to ULTRA1 to cause resonance.

On the other hand, for example, when the vibrator starts to vibrate at a frequency of 1 MHz, when the vibrator is placed on the user's skin, the vibrator is pressed, which in turn operates in a direction of suppressing vibration, resulting in a difference in current. This is detected by the voltage dividing resistors R18 and R20 of the current sensing unit 61. The weak sensed signal is amplified by the amplifier 62 and input to the analog input terminal AN6 of the CPU to be digitally converted, and finally output to the PWM output terminal (No. 10 pin) to the DC-DC converter unit 20 of the CPU. This increases the duty ratio of the signal. Thus, by stepping up the voltage from the 'low' (weak) level to the 'high' (strong) level, the vibrator still vibrates the same ultrasonically even if the vibrator is pressed against the skin so that it does not interfere with operation as a skin care device. By doing this, it is possible to reduce unnecessary power consumption by vibrating ultrasonic waves at a 'low' level while the user is not actually using the device even when the power is turned on.

Next, referring to FIG. 3, the configuration of the signal output unit of the display unit 40 and the beep generator 80 of the present invention is described. The photodiodes D6 and D7 displaying intensity control are provided in two ports in parallel. Photodiodes D8 and D9 connected to RB2 and RB3 and indicating mode adjustment of the first mode and the second mode are connected to two ports RB3 and RC0 in parallel, and mode adjustment of the third mode and the fourth mode. The photodiodes D11 and D13, which are connected to the two ports RC0 and RC1 in parallel, and the photodiodes D14, which indicate the user's usage status, are connected to the two ports RB2 and RC1 at both ends. By emitting multiple photodiodes at the port terminals, it is possible to reduce the total number of pins on the CPU, which in turn can lead to cost savings.

The alarm sound generating units R5, Q1, and BUZ1 of the member No. 80 are operation circuits of the buzzer BUZ1 for generating an alarm sound to indicate the case of an abnormal state or the use state as a sound.

The truth table for determining whether each LED emits light is shown in Table 1. For example, when the output of the input / output terminal RB2 (A) is '0' and the output of the input / output terminal RB3 (B) is '1', the LED (D7) indicating the current intensity adjustment step is 'high' is emitted. When the output of input / output terminal RB3 (B) is '0' and the output of input / output terminal RC0 (C) is '1', LED (D8) indicating the current ultrasonic mode 'level 1' is emitted. When the output of RC0 (C) is '0' and the output of the input / output terminal RC1 (D) is '1', the LED (D13) indicating the current ultrasonic wave mode 'Level 4' is emitted, and the input / output terminal RB2 (A When the output of 1) is '1' and the output of the input / output terminal RC1 (D) is '0', the rear indicator LED D14 indicating that the ultrasonic driver is currently operating on the skin may be configured to emit light.

Finally, the temperature sensing unit 70 of the present invention will be described with reference to FIG. 4. First, the first temperature sensing unit 71 is composed of a thermistor RT1 and a voltage dividing resistor R19, and is input to the CPU through the analog input terminal AN3. The surface temperature of the skin diaphragm of the ultrasonic vibrator of FIG. 5 to be described later is sensed, and as the ultrasonic vibrator is operated, the diaphragm is heated, thereby detecting an overheating at a predetermined temperature (for example, 45 °) or more, adversely affecting the skin. In order to prevent further overheating, the PWM control is automatically performed to reduce the duty ratio of the pulse wave input to the DC-DC converter to adjust the strength and weakness of the voltage.

In addition, the thermistor RT2 and the voltage dividing resistor R36 of the second temperature sensing unit 72 sense the temperature of the oscillation transistors Q3 and Q6 of the oscillation unit 54 of the ultrasonic driving unit of FIG. Also, if the temperature of the transistor is overheated by a predetermined value or more, the duty ratio of the PWM control signal is reduced to protect the circuit. The weak sensing signal passes through the amplifier circuits R37, R38, and U2A and is input to the analog input terminal AN4.

Hereinafter, a second embodiment of the present invention will be described with reference to the accompanying drawings.

9 is a block diagram of an ultrasonic ion skin care device according to a second embodiment of the present invention, FIG. 10 is a detailed circuit diagram of a power source and a switch unit of the ultrasonic ion skin care device according to a second embodiment of the present invention, and FIG. 12 is a detailed circuit diagram of the display unit of the ultrasonic ion skin care device according to the second embodiment of the present invention, FIG. 12 is a detailed circuit diagram of the laser and ultrasonic drive unit of the ultrasonic ion skin care device according to the second embodiment of the present invention, and FIG. FIG. 14 is a detailed circuit diagram of the galvanic driving unit and the body detecting unit of the ultrasonic ion skin care device according to the second embodiment of the present invention, and FIG. 14 is an external view of the instrument panel of the ultrasonic ion skin care device according to the second embodiment of the present invention, and FIG. 13 shows the applied voltage waveform of the galvanic driver. For simplicity of description, parts similar to those of the first embodiment of the components of the second embodiment are given like reference numerals, and descriptions thereof will be omitted, and the description will be mainly focused on differences.

9 and 10, according to the ultrasonic ion laser skin care device of the second embodiment of the present invention, in the second embodiment, the adapter method is used instead of the charging method. First, in the DC adapter, when the power switch SW1 is turned on, the voltage input through the connection terminals J1 and J3 is input to the DC-DC converter of the next stage. The voltage from the DC adapter 101 is boosted by the DC-DC converter section 120 in the same manner as in the first embodiment.

The remaining switch unit 130 and the reset unit 190 are also similar to the first embodiment. However, the second embodiment further includes a step control switch SW4 for driving the galvanic ion driver in addition to the mode and level control switches SW2 and SW3.

Meanwhile, referring to FIG. 11, the display unit 140 according to the second embodiment is substantially the same as that of the first embodiment of FIG. 3, but further includes an LED. That is, in the display device of the skin care device of the second embodiment, the first and second LEDs (D11 and D12 in FIG. 11) are connected between the first input / output terminal RD0 and the second input / output terminal RD1 of the control device CPU. The third and fourth LEDs (D16 and D17 in FIG. 11) are connected in parallel in opposite directions to each other and are opposite to each other between the second input / output terminal RD1 and the third input / output terminal RD2 of the control device CPU. Are connected in parallel, and the fifth and sixth LEDs (D21 and D22 of FIG. 11) are connected in parallel in opposite directions between the third input / output terminal RD2 and the fourth input / output terminal RC6 of the control unit CPU. A seventh LED (D15 in FIG. 11) is connected between the first input / output terminal RD0 and the fourth input / output terminal RC5 of the control unit CPU, and the eighth and ninth LEDs (D25 in FIG. 11). And D26 are connected in parallel between the fourth input / output terminal RC6 and the fifth input / output terminal RC5 of the control unit CPU in opposite directions to each other, wherein the respective LEDs are connected to the respective inputs from the control unit. By the signal value is on / off independently of the jacks.

The first to sixth LEDs D11, D12, D16, D17, D21, D22, D25, and D26 may be cleansing, massage, nutrition, lifting, whitening, or whitening. And a soft galvanic ion step and an ultrasonic mode operation, wherein the seventh LED D15 is used to indicate a state of use of the skin care device, and the eighth and ninth LEDs D25, D26) is used to indicate the intensity step of the ultrasound function. Of course, even in the galvanic ion step, it is possible to adjust the intensity of each mode.

In addition, the LED D27 indicating the ion introduction step informing the driving of the galvanic driver and the LED D28 informing the driving of the laser driver are connected to the output terminals RC4 and RC3.

Light emission conditions of each LED of the display device 140 of the second embodiment are shown in Table 2 below.

Next, the ultrasonic driver 15 and the laser driver 153 of the second embodiment will be described in detail with reference to FIG. 12. The ultrasonic driver includes the control signal from the output terminal AN3 of the microcontroller 102. And the resistor R22 are applied to the switching transistor Q4 to drive the ultrasonic driver ULTRA1 together with the resonant transistor Q3. The remaining elements R16, R18-R20, R23, L3- L5, C7-C11, and D9 are peripheral circuits of the transistors Q3 and Q4 and the ultrasonic driver.

The laser driver 153 receives a signal from the first laser output terminal AN0 of the microcontroller 102 to the photodiode PD and the laser diode LD, which is the second laser output terminal PWM1. It is controlled by the switching of the switching transistor Q1 by the output. The remaining D10, R7, R8, R9, R1, C5, C1 are additional elements.

Next, the galvanic driver 151 will be described with reference to FIG. 13. First, the pulse waveform control signal from the output terminal RB7 of the microcontroller 102 is amplified by the amplifying circuits U3A, R31, R33, R35, R37, C13, and integrated circuits U3B, R32, R38, R39, and R29. , C9, C10, and then applied via the resistors R34 and R36 to the contact electrodes J6 for the face and the contact electrodes J7, J8 for the hand, respectively.

At this time, the PWM control signals from the input / output terminals RB6 and RB7 of the microcontroller are applied to the PWM control transistors Q5 and Q6 through the resistors R54 and R55, respectively, and the collector sides of the transistors Q5 and Q6 are respectively face and face. Connected to the contact electrode of the hand, the output waveform forms a triangular waveform as shown in FIG. 15 in accordance with the PWM control signal. That is, when the signal of the terminal RB2 is 'high', the transistor Q55 is in the 'on' state, and the knob connection electrode is in the ground state, so that an output between t0-t1 in FIG. 15 occurs, and conversely, When the signal is 'high', the transistor Q5 is turned 'on' and the face connection electrode is grounded, so that an output between t1 and t2 in FIG. 15 is generated. Eventually, galvanic current flows alternately from face to hand or from face to face, and the ion active substance can be effectively introduced into the skin.

In addition, the member number 160 of FIG. 13 is a body detecting unit for detecting whether the electrode is in contact with the skin. The sensed signal is amplified by the amplifier circuits U3C, U3D, R42, R44, R46, R48, R49, R53, C11, and C12, and then to the microcontroller 102 via analog input terminals AN5 and AN6. Is entered.

Finally, referring to FIG. 14, the "power supply" switch, "ultrasound", "ion", "laser" drive switch in operation, each step drive switch in the ion introduction step, "weak" and "medium" in pulse level , Shows the "strong" level switch.

The above is merely described based on one embodiment of the present invention, and various modifications are possible without departing from the technical spirit of the present invention. For example, the beauty device is of course applicable to other beauty devices, such as ion implanter in addition to the ultrasonic beauty device. Therefore, the present invention should be construed as limited only by the following utility model registration claims.

As described in detail above, according to the display device of the skin care device according to the present invention, since various LEDs can be emitted even with a small number of connection terminals, the price of the CPU can be reduced, and the flexibility of the design can be achieved. Can greatly improve.

Claims (4)

In the display device of a portable skin care device, First and second LEDs (D7 and D6 in FIG. 3) connected in parallel between the first input / output terminals RB2 and RD0 and the second input / output terminals RB3 and RD1 of the control unit CPU, and connected in opposite directions. D11 and D12 of FIG. 11; Third and fourth LEDs (D8 in FIG. 3, respectively) connected in parallel between the second input / output terminals RB3 and RD1 and the third input / output terminals RC0 and RD2 of the control device CPU, and connected in opposite directions. D9, D16, D17 in Fig. 11); The fifth and sixth LEDs (D13 of FIG. 3, respectively) connected in parallel between the third input / output terminals RC0 and RD2 and the fourth input / output terminals RC1 and RC6 of the control device CPU are connected in opposite directions. D11 (D21, D22 in FIG. 11); And A seventh LED (D14 in FIG. 3; D15 in FIG. 11) connected between the first input / output terminal RB2 (RC6) and the fourth input / output terminal RC1; RC5 of the control device CPU; And each of the LEDs is independently turned on / off by a signal value of each input / output terminal from the control device. The method of claim 1, The first to sixth LEDs are used to indicate strength and mode operation, and the seventh LED is used to indicate the use state of the skin care device. The method of claim 1, The eighth and ninth LEDs (D25 and D26 of FIG. 11) connected in parallel between the fourth input / output terminal RC6 and the fifth input / output terminal RC5 of the control device CPU and connected in opposite directions are further connected. Display device comprising a. The method of claim 3, wherein The first to sixth LEDs are used to indicate the galvanic ion phase and the ultrasonic mode operation, and the seventh LEDs are used to indicate the use state of the skin care device, and the eighth and ninth LEDs are used to indicate the intensity step. Display device, characterized in that used to represent.