Cosmetic device and current control method

Abstract

Effectively applying currents of different frequencies. The beauty device (1) comprises a first electrode (11) and a second electrode (12) which is an annular electrode concentrically arranged around the first electrode and is arranged outside the first electrode. a third electrode (13) disposed outside the second electrode; a fourth electrode (14) disposed outside the third electrode; and a first circumferential electrode (15) disposed between the first electrode and the fourth electrode. and applying means (20) capable of applying a current of a second frequency to the skin between the second electrode and the third electrode while applying a current of a third frequency to the skin.

Description

[Technical Field]

[0001] The present invention relates to a beauty device that applies an electric current to the skin. [Background technology]

[0002] There are technologies that pass electric current through the skin for beauty and slimming purposes. Typical examples include those that aim to stimulate muscles (so-called EMS (Electric Muscle Stimulation)) and those that aim to provide a warming sensation (heating the skin from the inside using RF (Radio Frequency)). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-65693 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the current used for EMS (hereinafter referred to as EMS current) and the current used to achieve effects such as a warming sensation (hereinafter referred to as RF current) have different frequency bands. Therefore, there are appropriate conditions for applying EMS current and RF current, respectively. Specifically, with EMS, the larger the area of ​​the stimulation target, the greater the effect, and this area of ​​the stimulation target is determined by the distance between the electrodes that come into contact with the skin. Therefore, it is generally preferable for the electrodes to be farther apart. In addition, to achieve a certain level of effect, the current must be applied continuously for a certain period of time. On the other hand, it is known that the smaller the distance between the electrodes, the greater the effect when applying RF current. Here, even if the electrodes are far apart, it is possible to compensate for the reduced effect by increasing the applied frequency or increasing the application time, but high frequencies and extended application times may cause discomfort to the user. Thus, there is no suitable electrode arrangement that is common to both the application of EMS current and the application of RF current, at least in principle. In order to achieve both muscle stimulation and warming effects, it is possible to control the application time in a time-sharing manner or switch the frequency of the applied current, but this may result in a complex circuit configuration or may impose certain limitations on the frequency and amplitude of the applied current. As described above, with conventional beauty devices, it has been difficult to simultaneously achieve the effects of applying an EMS current and the effects of applying an RF current.

[0005] The present invention aims to provide a mechanism that can effectively apply currents of different frequencies simultaneously. [Means for solving the problem]

[0006] In one aspect, the present invention provides a beauty device having a first electrode, annular electrodes arranged concentrically around the first electrode, including a second electrode arranged outside the first electrode, a third electrode arranged outside the second electrode, and a fourth electrode arranged outside the third electrode, and an application means capable of applying a current of a first frequency to the skin between the first electrode and the fourth electrode, while applying a current of a second frequency to the skin between the second electrode and the third electrode. In a preferred embodiment, the first frequency is 1 Hz to 100 kHz, and the second frequency is 200 kHz to 4 MHz. In a preferred embodiment, the application means has a selection means for selecting, from the first to fourth electrodes, an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency, depending on at least one of the value of the first frequency and the value of the second frequency. In a preferred embodiment, the application means has a selection means for selecting, from the first to fourth electrodes, an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency, depending on at least one of the amplitude of the current of the first frequency and the amplitude of the current of the second frequency. In a preferred embodiment, the application means has a selection means for selecting, from the first to fourth electrodes, an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency, depending on at least one of the application period of the current of the first frequency and the application period of the current of the second frequency. In a preferred embodiment, the application means applies a current of a first RF frequency between the second electrode and the third electrode during a first period, and applies a current of a second RF frequency lower than the first RF frequency between the first electrode and the fourth electrode during a second period, and the first period and the second period are alternately repeated. In a preferred embodiment, the application means further applies the current of the second frequency continuously between the first electrode and the fourth electrode during the first period, and further applies the current of the second frequency intermittently between the second electrode and the third electrode during the second period. In a preferred embodiment, the device further comprises a sensor for detecting a current applied to the skin between the first electrode and the fourth electrode, and the application means stops applying at least the second frequency when a current having a value equal to or greater than a predetermined threshold is not applied to the skin between the first electrode and the fourth electrode for a predetermined period of time. In a preferred embodiment, the ratio of the length of the first period to the total application time is 70% or more. In a preferred embodiment, the distance between the second electrode and the third electrode is 1 mm to 3 mm, and at least one of the distances between adjacent electrodes is different from the others. In a preferred embodiment, each electrode protrudes from the head surface, and the sidewall surface of each electrode is inclined with respect to a direction perpendicular to the head surface. In another aspect, the present invention provides a current control method for a beauty device including a first electrode, a second electrode, a third electrode, and a fourth electrode, the beauty device being arranged so that the distance from the first electrode to the fourth electrode is greater than the distance from the second electrode to the third electrode, the current control method comprising: a first step of continuously applying a current of a second frequency between the first electrode and the fourth electrode while applying a current of a first RF frequency between the second electrode and the third electrode during a first period; and a second step of intermittently applying a current of the second frequency between the second electrode and the third electrode while applying a current of a second RF frequency lower than the first RF frequency between the first electrode and the fourth electrode during a second period, wherein the first RF frequency and the second RF frequency are 200 kHz to 4 MHz, and the second frequency is 1 Hz to 100 kHz, and the first step and the second step are alternately repeated.

[0007] According to the present invention, currents of different frequencies can be effectively applied simultaneously. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an external view of the beauty device 1. [Figure 2A] FIG. [Figure 2B] Examples of variations in size of the electrode 10 are shown. [Figure 2C] The results of the sensory test for each variation of the electrode 10 are shown. [Figure 3] 1 is a schematic diagram of the internal structure of the beauty device 1. [Figure 4] 10 is a schematic diagram of another example of the internal structure of the beauty device 1. FIG. [Figure 5] FIG. 10 is a diagram showing an example of a control pattern. [Figure 6] 10 shows another example of the shape of one of the electrodes constituting the electrode 10. [Figure 7] FIG. 10 is a diagram showing another example of a control pattern. [Figure 8] FIG. 10 is a diagram showing temperature changes corresponding to each control content. [Figure 9]FIG. 10 is a diagram for explaining the difference in temperature change when electrodes 10 having different inter-electrode distances are used. [Figure 10] FIG. 10 is a diagram showing an example of the area ratio between electrodes. [Figure 11] 5A and 5B are diagrams showing examples of the shape of the side walls of each electrode. [Figure 12] 5A and 5B are diagrams showing examples of the shape of the side walls of each electrode. [Figure 13] FIG. 3 is an exploded view showing an example of the structure of members constituting each electrode. [Figure 14] 2 is a diagram showing the structure of a casing 100. FIG. [Figure 15] FIG. 2 is a diagram showing a state in which each electrode member is fitted into a casing 100. [Figure 16] FIG. 2 is a diagram showing an example of a circuit board 200. [Figure 17] 2A and 2B are diagrams showing the structure of a coil spring 201. [Figure 18] FIG. 1 shows a circuit board 200 fitted into a casing 100. [Figure 19] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Example 1 FIG. 1 is an external view of a beauty device 1. The beauty device 1 has a housing 80 that is held by a user and an electrode 10 that is provided at the tip of the housing 80, which is in contact with the skin. The housing 80 is provided with a switch 90 that is operated by the user. The switch 90 is used to turn the power on / off, as well as to specify the frequency and time of the applied current and other application-related conditions. The housing 80 is also provided with a power connector and information display means such as an LCD screen, but these are not directly related to the present invention and are therefore omitted.

[0010] 2A is a detailed diagram of the structure of electrode 10. Electrode 10 is composed of a disk-shaped first electrode 11 located on the innermost side (near the center), a second electrode 12 located outside first electrode 11, a third electrode 13 located outside second electrode 12, and a fourth electrode 14 located outside (on the outermost side) third electrode 13, which are annular electrodes located concentrically around first electrode 11. In a preferred embodiment, when the distance from first electrode 11 to fourth electrode 14 is d1 and the distance from second electrode 12 to third electrode 13 is d2, d1 > d2.

[0011] It is preferable that the heights of the first electrode 11, second electrode 12, third electrode 13, and fourth electrode 14 from the surface of the housing are substantially the same so that they can be in contact with the skin simultaneously. The width (radial length), area, and spacing between adjacent electrodes of each electrode are merely examples.

[0012] For example, the distance between adjacent electrodes may be different from each other, such as the distance between the first electrode and the second electrode, the distance between the second electrode and the third electrode, and the distance between the third electrode and the fourth electrode. With regard to the area of ​​each electrode (the area of ​​the ring plane that can come into contact with the skin, not including the side surfaces), it is preferable that the area ratio of the first electrode 11 to the fourth electrode 14 is 1:1 or more and 1:1:7 or less. The reason for this will be explained using Figures 2B and 2C.

[0013] To verify the effect of the size and area of ​​each electrode on the user's sensation, we first prepared four sample electrodes (No. 1 to No. 4) with different sizes and areas for the first electrode 11 and the fourth electrode 14, as shown in Fig. 2B. In the figure, the inner electrode diameter and inner electrode area refer to the diameter and area of ​​the first electrode 11, and the outer electrode inner diameter, outer electrode outer diameter, and outer electrode area refer to the inner diameter, outer diameter, and area of ​​the fourth electrode 14, respectively. Note that the second electrode 12 and the third electrode 13 are not used to apply current, and therefore will not be described here. In addition, in all samples, the distance between adjacent electrodes was 2 mm, and the distance between the first electrode 11 and the fourth electrode 14 was 8 mm. In other words, when the distance between the first electrode 11 and the fourth electrode 14 and the distance between adjacent electrodes were kept constant, the experiment verified how differences in the area (ratio) of each electrode would affect the sensation. Specifically, a total of four sample electrodes were used to apply current of the same frequency, and responses were obtained from six subjects. The results are shown in Figure 2C. As shown in the figure, the order of best sensation was No. 1 = No. 2, No. 3, No. 4. Specifically, the order of strongest sensation of muscle stimulation was No. 1 = No. 2, No. 3, No. 4, and the order of strongest sensation of pain or other discomfort was No. 4, No. 3, No. 2 = No. 1. In other words, from the perspective of muscle stimulation effect, a ratio of the area of ​​the fourth electrode 14 to the area of ​​the first electrode 11 of 1 to 1.7 is preferable. Furthermore, the outer diameter of the fourth electrode 14 is 32 mm to 37 mm, which is comparable in compactness to conventional beauty devices.

[0014] 3 is a schematic diagram of the internal structure of the beauty device 1. The beauty device 1 includes an application unit 20 that can apply a current of a first frequency f1 to the skin between the first electrode 11 and the fourth electrode 14, while applying a current of a second frequency f2 to the skin between the second electrode 11 and the third electrode 13. The application unit 20 includes a first power supply circuit 21, a second power supply circuit 22, an isolation transformer 23, an isolation transformer 24, and a control unit 25.

[0015] The first power supply circuit 21 and the second power supply circuit 22 are realized by elements such as coils, resistors, rectifiers, capacitors, clock circuits, and the like, and generate AC currents of a first frequency f1 and a second frequency f2, respectively. A current of a first frequency f1 is applied between the first electrode 11 and the fourth electrode 14, and a current of a second frequency f2 is applied between the second electrode 12 and the third electrode 13. The first frequency f1 is, for example, 1 Hz (Hertz) to 100 kHz (Kilohertz). This frequency band mainly contributes to the muscle stimulation effect (EMS). The second frequency f2 is, for example, 200 kHz to 4 MHz (Megahertz), and preferably 200 kHz to 2 MHz. This frequency band is called radio frequency (RF) and mainly contributes to the hyperthermia effect. The voltage is, for example, 10 V (Volts) to 300 V. The frequency bands that can be generated by the first power supply circuit 21 and / or the second power supply circuit 22 may be separate from each other or may partially overlap.

[0016] In short, parameters such as the frequency to be generated can be set appropriately depending on the purpose of applying the current (muscle stimulation, heat, promoting penetration of lotion, etc.). The waveform of the current is, for example, an AC sine wave, but it may also be a unipolar square wave, a triangular wave, or other pulse train (in which case the above-mentioned frequency can be considered as a repetition frequency). Furthermore, the first frequency f1 and / or the second frequency f2 may be variable or fixed.

[0017] The insulating transformers 23 and 24 prevent currents generated in the second power supply circuit 22 and the first power supply circuit 21, respectively, and other unexpected currents from flowing in. That is, In the present invention, a closed circuit consisting of the first power supply circuit 21, the first electrode 11, and the fourth electrode 14, and a closed circuit consisting of the second power supply circuit 22, the second electrode 12, and the third electrode 13 are formed, and two types of current are applied to the skin simultaneously, but by providing the insulating transformers 23 and 24, current does not flow from one closed circuit to the other closed circuit.

[0018] The control unit 25 is a switch mechanism, a processor, etc., and supplies ON / OFF signals and control signals indicating the current profile to be generated (application time, frequency, voltage, waveform, etc.) to the first power supply circuit 21 and the second power supply circuit 22 in response to instructions received via the switch 90.

[0019] According to this embodiment, f1 < f2. For example, when the first frequency f1 is mainly the frequency for muscle stimulation purposes and the second frequency f2 is mainly set as the frequency for heating purposes, two currents can be applied simultaneously in a state where the electrode arrangement suitable for applying the first frequency f1 and the electrode arrangement suitable for applying the second frequency f2 are simultaneously realized. As a result, at substantially the same skin position, the muscle stimulation effect and the heating effect can be effectively given simultaneously.

[0020] Here, for example, when trying to achieve both the muscle stimulation effect and the heating effect by alternately switching and applying the current of the frequency for muscle stimulation purposes and the current of the frequency for heating purposes using the same electrode, when applying the current of the frequency for muscle stimulation at the electrode distance suitable for exerting the heating effect, the range of the stimulated muscle becomes narrow. Also, for example, when the electrode for applying the frequency current for muscle stimulation and the electrode for applying the frequency current for obtaining the heating effect are physically separated, the constraints on the available frequency band increase.

[0021] In contrast, according to this embodiment, a plurality of electrodes are arranged concentrically at an electrode distance suitable for applying the frequencies for obtaining the muscle stimulation effect and the heating effect, so that an appropriate muscle stimulation effect and heating effect can be simultaneously given to a wide range of the skin. As a result, for example, compared with the method of switching the frequency, the user's usage time is shortened. Also, since there is no need to perform control such as switching the application timing in a time-sharing manner, the circuit configuration can be simplified. In addition, since an annular electrode is adopted, the electrode pair can be surely brought into contact with the skin. As a result, the current flowing through the skin is stabilized, and the discomfort given to the user is reduced. Therefore, for example, even a user who is not used to handling the article according to this embodiment can use it without worrying about the direction and the force applied when applying the electrode 10 to the skin, unlike the case where rectangular electrodes are arranged opposite to each other. In addition, by arranging the electrodes on a concentric circle, it is possible to make the size of the portion contacting the skin compact while securing the area of the electrodes. Thereby, the design and operability of the entire beauty device are improved. Furthermore, by setting the area ratio of each electrode within the above-mentioned range, it is possible to reduce discomfort such as strong pain and localized heat.

[0022] <Example 2> FIG. 4 is a schematic diagram of another example of the internal structure of the beauty device 1. In FIG. In this example, a control unit 25A is used instead of the control unit 25, and an application unit 20A is used instead of the application unit 20. In the application unit 20A, a selection unit 26 is provided between the first power supply circuit 21 and the second power supply circuit 22 and each electrode. The control unit 25A determines to which of the first electrode 11 to the fourth electrode 14 the current generated by the first power supply circuit 21 and the second power supply circuit 22 is to be applied, and supplies a control signal to the selection unit 26. The selection unit 26 is made up of a switch circuit or the like, and switches the wiring based on the control signal supplied from the control unit 25A.

[0023] In a preferred embodiment, the selection unit 26 selects an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency from the first to fourth electrodes in accordance with at least one of the value of the first frequency and the value of the second frequency, thereby selecting an electrode pair suitable for the frequency.

[0024] In another aspect, the selection unit 26 selects an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency from the first to fourth electrodes in accordance with at least one of the amplitude of the current of the first frequency and the amplitude of the current of the second frequency, thereby determining electrodes suitable for the applied current intensity.

[0025] In yet another aspect, the selection unit 26 selects, from the first to fourth electrodes, an electrode pair to be used for applying the current of the first frequency or an electrode pair to be used for applying the current of the second frequency, depending on at least one of the application period of the current of the first frequency and the application period of the current of the second frequency, thereby selecting electrodes suitable for the application period.

[0026] If multiple operation modes are selectable in the beauty device 1, the electrodes to be used may be selected according to the operation mode. For example, a memory storing a table defining combinations of operation modes and electrodes to be used, as shown in Fig. 5, may be provided in the control unit 25A. Here, the operation mode may be directly specified by the user via the switch 90, or may be determined by the control unit 25A using a predetermined algorithm based on the purpose, frequency, amplitude (intensity), application time, and other application-related parameters specified by the user via the switch 90. In the example shown in the figure, the electrodes to which either the first frequency f1 or the second frequency f2 (or both) are applied are specified depending on the operating mode. Note that (+) and (-) in the figure indicate the anode and cathode of the electrode pair, respectively.

[0027] More specifically, in operation mode 1, a current of f1 is applied between the first electrode 11 and the fourth electrode 14, while a current of f2 is applied between the second electrode 12 and the third electrode 13. In operation mode 2, only a current of f1 is applied between the first electrode 11 and the fourth electrode 14. In operation mode 3, only a current of f2 is applied between the second electrode 12 and the third electrode 13. In operation mode 4, a current of f1 is applied between the first electrode 11 and the third electrode 13, while a current of f2 is applied between the second electrode 12 and the fourth electrode 14. Compared to operation mode 1, different electrodes are used. This is effective when f1 and f2 are relatively close values. In operation mode 5, first electrode 11 and second electrode 12 are set to an equipotential, and third electrode 13 and fourth electrode 14 are set to an equipotential, causing first electrode 11 and second electrode 12 to function as a single electrode (e.g., an anode), and third electrode 13 and fourth electrode 14 to function as a single electrode (e.g., a cathode), and a current of a single frequency is applied to this electrode pair. This is expected to be selected when the area of ​​the electrode in contact with the skin can affect the sensation, and the aim is to improve the sensation of the effect by increasing the apparent area of ​​the electrode in contact. For the same purpose, in operation mode 6, second electrode 12, third electrode 13, and fourth electrode 14 function as one part of an electrode pair. In this way, electrodes can be flexibly selected depending on the purpose, frequency, and other application modes.

[0028] First electrode 11, which is located in the innermost position, may be annular instead of disk-shaped. In this case, a mechanism for irradiating light onto the skin, such as an LED, may be provided in the space formed in the center of first electrode 11. Furthermore, the number of electrodes included in electrode 10 may be five or more, as long as the electrodes are annular and arranged concentrically and have different diameters. Increasing the number of concentrically arranged annular electrodes increases the number of types of current that can be applied simultaneously. Furthermore, each electrode does not have to be a perfect circular ring, but may be an elliptical ring, a rectangular ring, a polygonal ring (e.g., a triangular ring with rounded corners), a heart-shaped ring, or any other hollow shape. In other words, the "annular" in the present invention refers to any hollow structure, and may be, for example, a shape such as a circular ring member with protrusions formed thereon as shown in Fig. 6, or the outer shape or inner diameter may be distorted from a circle. However, it is preferable that at least the distance between the electrodes that make up an electrode pair (for example, the first electrode 11 and the fourth electrode) is constant regardless of position (in other words, that the shapes of both electrodes are similar). If the distance between the electrodes is constant, the amount of current applied and the sensation given to the user will be uniform depending on the location on the skin.

[0029] Example 3 The application means 20 may apply a current of a first RF frequency between the second electrode 12 and the third electrode 13 in a first period, and may apply a current of a second RF frequency lower than the first RF frequency between the first electrode 11 and the fourth electrode 14 in a second period. The first period and the second period may be alternately repeated. Furthermore, the application means 20 may further apply the current of the second frequency continuously between the first electrode and the fourth electrode during the first period, and further apply the current of the second frequency intermittently between the second electrode and the third electrode during the second period.

[0030] 7 shows a specific example of such current application control. In this example, the applied AC current is roughly divided into two types: RF current and EMS current. The distance between the second electrode 12 and the third electrode 13 is 2 mm, and the distance between the first electrode 11 and the fourth electrode 14 is 8 mm. As shown in the figure, application periods T0, T1, and T2 are set in order from the time the power is turned on. During period T0, an EMS current of 71 to 100 Hz is applied for 30 seconds using the first electrode 11 and the fourth electrode 14. Simultaneously, an RF current of 2 MHz is applied using the second electrode 12 and the third electrode 13. Here, for RF current, the closer the distance between the two electrodes used for application, the greater the thermal effect. On the other hand, for EMS current, the longer the distance between the electrodes, the better the sensation (the user is less likely to feel a tingling or other discomfort) and the more widely the muscles can be stimulated (thereby moving the muscles). That is, during period T0 immediately after power-on, the second electrode 12 and the third electrode 13, an electrode pair suitable for providing a thermal effect, are used to first sufficiently warm the skin, and then the first electrode 11 and the fourth electrode 14, an electrode pair suitable for firmly moving the muscles, are used to stimulate the muscles so that they sandwich the heated skin area.

[0031] During period T1 following period T0, the electrodes used are switched, and RF current (1 MHz) is applied between the first electrode 11 and the fourth electrode 14 for 2 seconds, while EMS current (1 kHz) is applied at a repetition frequency of 10 Hz using the second electrode 12 and the third electrode 13. By applying RF current to the first electrode 11 and the fourth electrode 14, which is the combination with the greatest electrode distance, a wide area can be heated. However, as mentioned above, the closer the electrodes used for application of the EMS current, the stronger the physical sensation (increased discomfort). Therefore, the EMS current is applied intermittently (i.e., there are periods when the EMS current does not flow). While a frequency of 1 kHz is considered relatively less uncomfortable, it also does not induce muscle contraction. Therefore, applying the current intermittently promotes muscle contraction more effectively than continuous application.

[0032] During period T2 following period T1, an RF current (2 MHz) is passed between second electrode 12 and third electrode 13 for 10 seconds, and an EMS current (71-100 Hz) is passed between the first and fourth electrodes for 10 seconds. That is, an electrode pair suitable for applying RF current is used to apply a 2 MHz current, a frequency suitable for a hyperthermic effect. This sufficiently raises the skin temperature, improving blood circulation and providing electrical stimulation to relaxed muscles. In other words, a synergistic effect is expected between muscle stimulation by the EMS current and the hyperthermic effect of the RF current.

[0033] Thereafter, periods T1 and T2 are repeated, and the application is continued for, for example, six minutes, after which the operation is terminated. In this way, by using an electrode pair suitable for applying RF current, a first RF frequency that is expected to have rapid heating properties is applied in the first period (T1), and a second RF frequency that targets a wide area and has a more moderate heating capacity is applied in the second period (T2), thereby achieving both rapid heating and temperature stability (preventing overheating). The lengths of the above-mentioned periods T0, T1, and T2 are examples. Period T0 is preferably 20 to 40 seconds, period T1 is preferably 2 to 10 seconds, and period T2 is preferably 5 to 15 seconds. From the viewpoint of maintaining skin temperature, the length of the first period T1 preferably accounts for 70% to 80% or more of the total application time.

[0034] Here, we will explain in detail why 1 MHz or 2 MHz is used as the RF current in the example of Figure 7. Figure 8 shows the results of an experiment showing how the temperature changed when three different RF current application patterns were applied for a total of 90 seconds.

[0035] (A) shows the temperature change when a 2 MHz RF current is continuously applied between the second electrode 12 and the third electrode 13 for 90 seconds. (B) shows the temperature change when, as shown in Fig. 7, a 1 MHz RF current is applied between the second electrode 12 and the third electrode 13 for 2 seconds, followed by a 2 MHz RF current for 10 seconds between the first electrode 11 and the fourth electrode 14, and then a process of applying a 1 MHz RF current for 2 seconds and a process of applying a 2 MHz RF current for 10 seconds is repeated. (C) shows the temperature change when a 1 MHz RF current is continuously applied between the first electrode 11 and the fourth electrode 14 for 90 seconds.

[0036] As can be seen from the figure, in cases (A) and (B), the skin temperature, considered desirable for skin care, remains around 40°C, whereas in case (C), it does not reach 40°C. This is because the distance between the electrodes used is greater than in case (A), which prevents the thermal effect from being fully exerted. On the other hand, it was found that even when applying 1 MHz and 2 MHz alternately while switching the electrodes used, as in case (B), the same thermal effect can be obtained as when applying 2 MHz continuously, as in case (A). Here, when applying RF current as in case (A), the electrodes that use the EMS current simultaneously must be the second electrode 12 and the third electrode 13, which results in a worsening of the physical sensation, as described above. In contrast, by controlling the electrode switching as in case (B) (i.e., Figure 7), it is possible to achieve both the thermal effect of the RF current and the prevention of the worsening of the physical sensation caused by the EMS current.

[0037] The reason for setting the inter-electrode distance to 2 mm will be explained in detail below. Figure 9 shows experimental results showing how skin temperature changes depending on the distance between two concentric ring electrodes and the applied RF current. Figure 9 (a) shows the case where the RF current is 1 MHz and the inter-electrode distance is 3 mm, while Figure 9 (b) shows the case where the RF current is 2 MHz and the inter-electrode distance is 2 mm. As shown in Figure 9, it was confirmed that case (b) is superior in terms of rapid heating (has a faster warming effect). Experiments also revealed that an inter-electrode distance of 1 mm is perceived as uncomfortable (too hot). Based on this, in the example of Figure 7, the preferred electrode spacing for applying RF current is set to 2 mm. In other words, the spacing between the second electrode 12 and the third electrode 13 is preferably 1 mm to 3 mm. Among electrodes 11 to 14, at least one of the spacings between adjacent electrodes is different from the others. This increases the variation in inter-electrode spacing for any two electrodes.

[0038] Example 4 An example of the area (size) of each electrode is shown in Figure 10. The areas of the first electrode 11 to the fourth electrode 14 are 118.0 mm^2, 113.7 mm^2, 170.6 mm^2, and 164.6 mm^2, respectively. In this case, no matter which two electrodes are selected, it is preferable that the size between the electrodes be approximately 1.0 to 1.5 times. This is because, in an electrode pair used to apply RF current or EMS current, if the area ratio of one electrode to the other is large, it will lead to a reduction in the thermal effect or stimulation effect or a worsening of the physical sensation.

[0039] <Example 5> The three-dimensional shape of each of the electrodes 11-14 does not necessarily have to be rectangular in cross section. For example, as shown in FIG. 11, the side surface (side wall surface) of the fourth electrode 14 may be inclined at a predetermined angle (35 degrees in this case) with respect to a direction C1 perpendicular to the contact surface SS (head surface) of the electrode 10. This predetermined angle is set so that the side surface of the fourth electrode 14 is continuous with the edge surface (C2) of the head portion of the housing 80 (see FIG. 12). This allows not only the surface ST of the fourth electrode 14 but also the side surface SW to be in contact with the skin. As a result, the effective electrode area of ​​the fourth electrode 14 increases, and the current applied using the fourth electrode 14 increases.

[0040] Example 6 An example of the internal structure of the electrode 10 will be described with reference to FIGS. Fig. 13 is an exploded view showing an example of the structure of the components that make up each of the electrodes 11 to 14. Each of the electrodes 11 to 14 has a shape in which three protrusions are formed on a metal ring. Figs. 14 and 15 show the structure of a casing 100 into which these metal rings are fitted (implanted and fixed). 16 is a diagram showing a circuit board 200 for applying a voltage to the casing 100 in which the metal ring group is fitted. The circuit board 200 is provided with a plurality of conical (tapered) coil springs 201 as shown in FIG. 18 and 19 show circuit board 200 assembled to casing 100 fitted with a group of metal rings. As shown in the figures, each electrode member is fixed via coil spring 201 by abutting the protrusion of each electrode member and pressing the electrode member against casing side 100. Coil spring 201 is preferably in a cone shape (such as a triangular pyramid or a cone) with the area of ​​its apex being 50% or less of the area of ​​its base.

[0041] When treating small areas such as the face, there are limitations on the size of the head, and arranging multiple electrodes concentrically inevitably reduces the width of each electrode. For example, the electrode width may be 2 mm or less. In light of this situation, in order to stabilize the electrical current even with thin electrodes, the electrode side protrudes from the insulating part and electricity is passed through a tapered coil spring.

[0042] Example 7 The cosmetic device 1 may further include a sensor that detects the current applied to the skin between the first electrode 11 and the fourth electrode, so that RF current does not flow when the skin is not in contact with the entire surface of the electrode. Incomplete contact between the skin and the electrode can cause the skin to overheat, but the purpose of not flowing RF current is to prevent this from happening. For example, if a current having a value equal to or greater than a predetermined threshold is not applied to the skin between the first electrode and the fourth electrode for a predetermined period of time, the application means 20 stops applying at least the second frequency. More specifically, a small RF voltage is applied between the first electrode 11 and the fourth electrode 14, and the difference in the applied current value (amplitude) when the electrode is not in contact with the skin and when it is in contact with the skin is detected, and whether the difference exceeds a threshold is used to determine whether the electrode (whole surface) is in contact with the skin. For example, as follows. When the power is turned on, it is determined that there is no contact with the skin. After determining that the skin is not being touched, if the current value of the first threshold flows for 50ms or more, it is determined that the skin has been touched. If a current value equal to or greater than the first threshold continues to flow for 25 ms or more after determining that the device is touching the skin, the device will determine that the device is still touching the skin. If the current value remains below the second threshold for more than 3 seconds after determining that the device is touching the skin, the device is determined to have left the skin (no longer touching the skin).

[0043] Example 8 The electrodes 11 to 14 do not need to be arranged concentrically. In a preferred embodiment, the cosmetic device 1 includes a first electrode, a second electrode, a third electrode, and a fourth electrode, and the electrodes are arranged such that the distance from the first electrode to the fourth electrode is greater than the distance from the second electrode to the third electrode. In this electrode arrangement, the method includes a first step of continuously applying a current of a second frequency between the first electrode and the fourth electrode while applying a current of a first RF frequency between the second electrode and the third electrode during a first period, and a second step of intermittently applying a current of a second RF frequency lower than the first RF frequency between the first electrode and the fourth electrode during a second period, the first RF frequency being 200 kHz to 4 MHz, the second frequency being 1 Hz to 100 kHz, and the first and second steps being alternately repeated. This allows for both the hyperthermia effect of the first RF frequency and the muscle stimulation effect of the second RF frequency to be achieved. [Explanation of symbols]

[0044] REFERENCE SIGNS LIST 1 beauty device, 10 electrode, 11 first electrode, 12 second electrode, 13 third electrode, 14 fourth electrode, 20 application means, 21 first power supply circuit, 22 second power supply circuit, 23 isolation transformer, 24 isolation transformer, 25 control unit, 26 selection unit, 80 housing, 90 switch, 100 casing, 200 circuit board

Claims

1. A first electrode; A second electrode; A third electrode; A fourth electrode; an application means for applying a current of a first frequency of 1 Hz to 100 kHz to the skin using two electrodes selected from the first electrode, the second electrode, the third electrode, and the fourth electrode, and applying a current of a second frequency of 200 kHz to 4 MHz to the skin using two electrodes other than the two selected electrodes; A beauty device having:

2. the second electrode is disposed outside the first electrode, the third electrode is disposed outside the second electrode, The fourth electrode is disposed outside the third electrode. The beauty device according to claim 1.

3. The applying means during a first period, applying a current having a first RF frequency belonging to the second frequency band between the second electrode and the third electrode; during a second period, a current having a second RF frequency that belongs to the second frequency band and is lower than the first RF frequency is applied between the first electrode and the fourth electrode; The first period and the second period are repeated one after another. The beauty device according to claim 1.

4. The applying means During the first period, a current of the first frequency is continuously applied between the first electrode and the fourth electrode; During the second period, a current of the first frequency is further applied intermittently between the second electrode and the third electrode. The beauty device according to claim 3.

5. The ratio of the length of the first period to the total application time is 70% or more. The beauty device according to claim 3 or 4.

6. A first electrode; A second electrode; A third electrode; A fourth electrode; an application means for determining at least two electrodes from among the first electrode, the second electrode, the third electrode, and the fourth electrode, which have an inter-electrode distance corresponding to the frequency of the current to be applied, and applying the current of the frequency to the skin using the determined at least two electrodes; and the applying means determines the at least two electrodes further based on the amplitude of the applied current. beauty equipment.

7. A first electrode; A second electrode; A third electrode; A fourth electrode; an application means for determining at least two electrodes from among the first electrode, the second electrode, the third electrode, and the fourth electrode, which have an inter-electrode distance corresponding to the frequency of the current to be applied, and applying the current of the frequency to the skin using the determined at least two electrodes; and The application means determines the at least two electrodes further based on an application period of the applied current. beauty equipment.

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