WO2024080052A1

WO2024080052A1 - Skin treatment device and electroconductive sheet

Info

Publication number: WO2024080052A1
Application number: PCT/JP2023/033065
Authority: WO
Inventors: 英明小島
Original assignee: ヤーマン株式会社
Priority date: 2022-10-12
Filing date: 2023-09-11
Publication date: 2024-04-18

Abstract

[Problem] To provide a skin treatment device that is capable of applying, in response to a request of a user, skin treatment to a skin surface in a variety of areas. [Solution] According to one embodiment of the present invention, a skin treatment device is provided. This skin treatment device comprises: an electroconductive sheet at least part of which is stretchable in a given direction, or an electroconductive sheet at least part of which is flexible so as to be capable of following a skin surface; and a device body which is attached to the electroconductive sheet to supply electric current to the skin surface of a user. The electroconductive sheet has a sheet base material, an electroconduction pattern, and a bioadhesive layer. The electroconduction pattern is provided to one surface side of the sheet base material, and comprises a wiring part and an electrode part that is connected to one end side of the wiring part. The bioadhesive layer is provided to a side of the electroconduction pattern opposite to the sheet base material, and is configured so as to be adhered to the skin surface of the user.

Description

Skin treatment device and conductive sheet

The present invention relates to a skin treatment device and a conductive sheet.

Conventionally, devices have been developed with the aim of enhancing cosmetic effects on the face (see Patent Document 1).
As such a device, Patent Document 1 discloses a beauty mask that is worn on the face of a user and performs treatment using electrical stimulation.
This beauty mask comprises a mask body that covers almost the entire area of the user's face, and a stimulator that is attached to the mask body and applies treatment waves to continuously impart electrical stimulation having a predetermined current intensity to the areas corresponding to the user's cheeks.

Patent Publication 2022-116856

However, the above-mentioned cosmetic mask has a problem in that the treatment area is limited to the cheeks of the user's face.
In view of the above circumstances, the present invention provides a skin treatment device capable of performing skin treatment on the skin surface in various regions in response to the needs of a user.

According to one aspect of the present invention, a skin treatment device is provided. This skin treatment device comprises a conductive sheet, at least a portion of which is stretchable in any direction, or a conductive sheet having flexibility such that at least a portion of the conductive sheet can conform to the skin surface, and a device main body that is attached to the conductive sheet and supplies current to the skin surface of the user. The conductive sheet comprises a sheet base material, a conductive pattern, and a bioadhesive layer. The conductive pattern is provided on one side of the sheet base material and comprises a wiring section and an electrode section connected to one end of the wiring section. The bioadhesive layer is provided on the side of the conductive pattern opposite the sheet base material, and is configured to be attached to the skin surface of the user.

This aspect makes it possible to provide a skin treatment device that can treat the skin surface in various areas according to the user's needs.

FIG. 1 is a plan view showing a disassembled state of a skin treatment device according to the present embodiment. FIG. 2 is a plan view showing the device body in FIG. 1 turned upside down. FIG. 3 is a plan view showing an exploded state of the conductive sheet of the first configuration example. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a block diagram showing the configuration of the main body of the device. FIG. 6 is a plan view showing an exploded state of a conductive sheet having a bioadhesive layer of another configuration. FIG. 7 is a cross-sectional view of the conductive sheet of FIG. 6 corresponding to FIG. FIG. 8 is a plan view showing an exploded state of a skin treatment device including a conductive sheet of the second configuration example. FIG. 9 is a plan view showing a conductive sheet according to a third configuration example. FIG. 10 is a plan view showing a conductive sheet according to a fourth configuration example. FIG. 11 is a bottom view showing the conductive sheet of the fifth configuration example. FIG. 12A is a plan view showing the conductive sheet 1 of the sixth configuration example, and FIG. 12B is a side view showing the conductive sheet 1 of the sixth configuration example. Fig. 13 is a cross-sectional view taken along line BB in Fig. 12(a).

Below, an embodiment of the present invention will be described with reference to the drawings. The various features shown in the following embodiment can be combined with each other.

The program for realizing the software appearing in this embodiment may be provided as a non-transitory computer-readable recording medium, or may be provided so that it can be downloaded from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

In this embodiment, a "unit" can also include, for example, hardware resources implemented by a circuit in the broad sense, and software information processing that can be specifically realized by these hardware resources. In addition, this embodiment handles various types of information, which can be represented, for example, by physical values of signal values representing voltage and current, high and low signal values as a binary bit collection consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations can be performed on a circuit in the broad sense.

In addition, a circuit in the broad sense is a circuit that is realized by at least appropriately combining a circuit, circuitry, a processor, and memory. In other words, it includes application specific integrated circuits (ASICs), programmable logic devices (e.g., simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

First, the skin treatment device of the present invention will be described.
Fig. 1 is a plan view showing an exploded state of the skin treatment device according to the present embodiment. Fig. 2 is a plan view showing a state in which the device main body in Fig. 1 is turned upside down. Fig. 3 is a plan view showing a state in which the conductive sheet of the first configuration example is exploded. Fig. 4 is a cross-sectional view taken along line A-A in Fig. 1. Fig. 5 is a block diagram showing the configuration of the device main body.
In the following description, the front side of the paper in Figures 1 to 3 will also be referred to as the "front" or "top", the back side of the paper in Figures 1 to 3 will also be referred to as the "back" or "bottom", the upper side in Figure 4 will also be referred to as the "front" or "top", and the lower side in Figure 4 will also be referred to as the "back" or "bottom".
1 and 2, a skin treatment device 100 is attached to the skin of a user for use. The skin treatment device 100 includes a conductive sheet 1, at least a portion of which is stretchable in any direction, and a device main body 10 that is attached to the conductive sheet 1 and supplies an electric current to the skin of the user.

<First Configuration Example>
First, a first configuration example of the conductive sheet 1 will be described.
As shown in Figures 3 and 4, the conductive sheet 1 has a sheet substrate 2, a conductive pattern 3, and a bioadhesive layer 4. In Figures 1 and 2, the conductive pattern 3 located on the back side (lower side) of the sheet substrate 2 is shown with oblique lines.
1 and 3, the sheet base material 2 has a pair of generally rounded wide portions 21 and a narrow portion 22 connecting the wide portions 21, which are integrally formed. With this configuration, the sheet base material 2 has a dumbbell-like shape in a plan view.
Furthermore, an ear 23 is formed protruding from the end of one of the wide portions 21 opposite the narrow portion 22. By gripping and manipulating this ear 23 with fingers or the like, the skin treatment device 100 can be smoothly peeled off (removed) from the skin surface of the user.

The sheet substrate 2 functions as a support layer that supports the conductive pattern 3 and the bioadhesive layer 4. The sheet substrate 2 is stretchable in any direction.
Examples of the sheet substrate 2 include resin sheets such as polyethylene terephthalate sheets, polypropylene sheets, and polyethylene sheets; thermoplastic elastomer sheets such as urethane-based thermoplastic elastomer sheets; rubber sheets such as nitrile rubber sheets and urethane rubber sheets; paper substrates, woven fabrics, nonwoven fabrics, foam sheets, and the like; and laminated sheets obtained by laminating these.
The thickness of the sheet substrate 2 is not particularly limited, but from the viewpoint of ensuring high conformability of the conductive sheet 1 to the skin surface, it is preferably approximately 10 μm or more and 200 μm or less, and more preferably approximately 25 μm or more and 150 μm or less.

The durometer hardness A of the sheet base material 2 is preferably about 10 or more and about 80 or less, and more preferably about 30 or more and about 70 or less. This can further improve the degree of deformation (bending, stretching, etc.) of the sheet base material 2, and can also increase the friction durability and mechanical strength of the sheet base material 2.
The durometer hardness A of the sheet substrate 2 can be obtained by preparing a sheet-like test piece using the sheet substrate 2 and measuring the durometer hardness A at 25° C. in accordance with JIS K 6253 (1997).

The tear strength of the sheet base material 2 is preferably about 25 N/mm or more and 80 N/mm or less, and more preferably about 30 N/mm or more and 70 N/mm or less. This can improve the durability of the sheet base material 2 during repeated use. In addition, the sheet base material 2 can be made less susceptible to breakage even if it is made thin. This allows the design freedom to be increased while balancing the various properties of the sheet base material 2.
The tear strength of the sheet substrate 2 is obtained by preparing a crescent-shaped test piece using the sheet substrate 2 and measuring the tear strength at 25° C. in accordance with JIS K6252 (2001).

The breaking elongation of the sheet base material 2 is preferably about 100% or more and about 2000% or less, more preferably about 200% or more and about 1900% or less, and even more preferably about 300% or more and about 1800% or less. This makes it possible to improve the high elasticity and durability of the sheet base material 2 while balancing the various properties of the sheet base material 2.
The breaking elongation of the sheet base material 2 can be calculated by preparing a dumbbell-shaped No. 3 test piece using the sheet base material 2 in accordance with JIS K 6251 (2004), measuring the breaking elongation at 25°C, and calculating the breaking elongation by [gage mark distance (mm)]÷[initial gage mark distance (20 mm)]×100.

The tensile strength of the sheet base material 2 is preferably about 5 MPa or more and 25 MPa or less, and more preferably about 10 MPa or more and 20 MPa or less. This makes it possible to improve the mechanical strength of the sheet base material 2 while balancing the various properties of the sheet base material 2. In addition, it is possible to realize a sheet base material 2 having excellent durability that can withstand repeated deformation.
The tensile strength of the sheet substrate 2 is obtained by preparing a dumbbell-shaped No. 3 test piece using the sheet substrate 2 and measuring the tensile strength at 25°C in accordance with JIS K 6251 (2004).

The sheet substrate 2 preferably has high gas permeability (high oxygen permeability, high water vapor permeability), so that the skin surface is less likely to be damaged when the skin surface is treated by the skin treatment device 100.
Specifically, the oxygen permeability of the sheet substrate 2 is not particularly limited, but is preferably about 1×10 ³ cm ³ /m ² ·24h·atm or more, and more preferably about 2×10 ³ cm ³ /m ² ·24h·atm or more.
The water vapor permeability of the sheet substrate 2 is not particularly limited, but is preferably about 5 g/m ² ·24 h ·atm or more, and more preferably about 10 g/m ² ·24 h ·atm or more.

The sheet substrate 2 (narrow width portion 22 ) has two through holes 221 and two openings 222 formed therein.
2 of the device body 10 are inserted into the two through holes 221. By inserting the pins 101 into the through holes 221, the device body 10 can be positioned relative to the conductive sheet 1. That is, the skin treatment device 100 has a positioning portion of the device body 10 relative to the conductive sheet 1, which is composed of the pins 101 and the through holes 221.
A part of the conductive pattern 3 is exposed in each opening 222. The device body 10 has a pair of terminal portions 11 as shown in Fig. 2. When the device body 10 is positioned relative to the conductive sheet 1, the terminal portions 11 are inserted into the corresponding openings 222 and come into contact with the conductive pattern 3. This electrically connects the device body 10 and the conductive pattern 3.

The conductive pattern 3 is provided on the lower surface (one surface) of the sheet base material 2. The conductive pattern 3 may be disposed in direct contact with the sheet base material 2, or may be disposed via an intermediate layer for any purpose. Functions of the intermediate layer include, for example, a function of increasing the adhesion between the conductive pattern 3 and the sheet base material 2, a function of reinforcing the conductive pattern 3, and a function other than current conduction (for example, a heating function and a magnetic force imparting function, which will be described later).
3, the conductive patterns 3 are provided in a pair on the left and right sides, and the two conductive patterns 3 have approximately the same shape. Each conductive pattern 3 includes three wiring parts 31 and an electrode part 32 connected to one end of each wiring part 31. By dividing and arranging the electrode parts 32 in this way, it becomes easier to supply current more uniformly to the skin surface.

The three wiring portions 31 join together at the other end to form a joining portion 33 .
The connecting portion 34 protruding further toward the other end side is integrally formed from the junction 33. As described above, the sheet base material 2 has the opening 222 through which the connecting portion 34 is exposed.
When the device body 10 is attached to the conductive sheet 1, the terminal portion 11 is inserted into the corresponding opening 222 and comes into contact with the connection portion 34. That is, the wiring portion 31 has the connection portion 34 connected to one of the terminal portions 11 on the other end side.
Such a conductive pattern 3 can also be expanded or contracted in any direction.

The conductive pattern 3 can be made of, for example, a composite material (elastic conductive material) containing a conductive filler and an elastomer.
Examples of the conductive filler include carbon materials such as carbon nanotubes and carbon nanohorns, and metal materials such as gold, silver, copper, and nickel.
Examples of the elastomer include thermoplastic elastomers such as polyamide-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and urethane-based thermoplastic elastomers, and rubber materials such as ethylene propylene rubber, neoprene rubber, natural rubber, and silicone rubber.
With such a composite material, the conductive pattern 3 can be produced relatively easily using a printing method.

The thickness of the conductive pattern 3 is not particularly limited, but from the viewpoint of ensuring high conformability of the conductive sheet 1 to the skin surface and the mechanical strength of the conductive pattern 3, it is preferable that the thickness be approximately 1 μm or more and 50 μm or less, and more preferably approximately 5 μm or more and 25 μm or less.
When the resistance value (25°C) of the entire combination of the conductive pattern 3 and the bioadhesive layer 4, or of the conductive pattern 3 alone when not stretched (natural state), is R1 [Ω], and the resistance value (25°C) of the entire combination of the conductive pattern 3 and the bioadhesive layer 4, or of the conductive pattern 3 alone when stretched by 50%, is R2 (Ω), it is preferable to satisfy the relationship 1<R2/R1≦20, more preferably to satisfy the relationship R2/R1≦18, and even more preferably to satisfy the relationship R2/R1≦16. With this level of resistance fluctuation, a current can be stably supplied to the skin surface.
R1, when measured as the resistance between the lower surface (skin side) of the bioadhesive layer 4, or, when the bioadhesive layer 3 is omitted, the lower surface (skin side) of the conductive pattern 3 and the upper surface (power supply connection) of the connection part 34, is preferably about 1000Ω or less, more preferably about 600Ω or less, even more preferably about 500Ω or less, particularly preferably about 400Ω or less, and most preferably about 300Ω or less. R2 is preferably about 5000Ω or less, more preferably about 2000Ω or less, and even more preferably about 1500Ω or less.

In this specification, the stretchability of the conductive pattern 3 is represented by the stretch rate when the conductive pattern 3 is stretched in a certain direction. The certain direction may be, for example, the extension direction in which the wiring portion 31 extends.
When the conductive pattern 3 is stretched in this extension direction, the extension rate is preferably about 10% or more, more preferably about 20% or more, and even more preferably about 50% or more, and means a state in which no break occurs in the conductive pattern 3 when stretched at that extension rate. A conductive pattern 3 that satisfies such conditions can be determined to have stretchability.
1 and 2, a part of the wiring portion 31 and the electrode portion 32 is disposed along the outer edge of the sheet base material 2. This allows a current to be supplied more uniformly to the area of the skin surface to which the conductive sheet 1 is attached.

The bioadhesive layer 4 is provided on the opposite side of the conductive pattern 3 to the sheet substrate 2. This bioadhesive layer 4 is configured to be attached to the skin surface of a user. In other words, the bioadhesive layer 4 has the function of holding the entire skin treatment device 100 on the skin surface of the user.
The adhesive strength of the bioadhesive layer 4 varies slightly depending on the shape and size of the conductive pattern 3, but is preferably about 0.5 N/20 mm to 10 N/20 mm, and more preferably about 1 N/20 mm to 6 N/20 mm. If the bioadhesive layer 4 has an adhesive strength in this range, the conductive pattern 3 can be more reliably held against the skin surface of the user.
The adhesive strength of the bioadhesive layer 4 refers to the adhesive strength when peeled off at an angle of 90° in accordance with the adhesive tape test method of JIS Z 0237:2009.

3, a pair of bioadhesive layers 4 are provided on the left and right sides, and the two bioadhesive layers 4 have approximately the same shape. Each bioadhesive layer 4 has a size sufficient to encompass the conductive pattern 3 in a plan view. By covering the entire conductive pattern 3 with the bioadhesive layer 4 in this way, it becomes easier to supply current more uniformly to the skin surface.
The bioadhesive layer 4 can be obtained by supplying the material for forming a bioadhesive layer before gelation onto a release sheet to form a coating film and crosslinking it. Alternatively, the material for forming a bioadhesive layer before gelation may be supplied so as to cover the conductive pattern 3 and crosslinked to obtain the bioadhesive layer 4.
Examples of the crosslinking (polymerization) method include a method in which the bioadhesive layer-forming material is heated, irradiated with light, or irradiated with radiation.

Such a bioadhesive layer 4 is also stretchable in any direction.
The bioadhesive layer 4 is preferably a gel having adhesive strength to the skin surface, particularly a high water content adhesive gel, that is, the bioadhesive layer 4 is preferably in the form of a gel.
The water content of the high water content adhesive gel is not particularly limited, but is preferably about 10% by mass to 60% by mass, and more preferably about 15% by mass to 50% by weight. When a skin topical agent is used in combination, the water content of the bioadhesive layer 4 is suppressed from swelling, and the adhesive strength of the conductive pattern 3 can be prevented or suppressed from decreasing.
The highly hydrated adhesive gel is preferably a hydrogel containing, in addition to water, a polymer matrix and a plasticizer, and, if necessary, an electrolyte and a water-soluble polymer. The highly hydrated adhesive gel may also contain an active ingredient contained in a skin topical preparation as described below. In this case, a plurality of fine needle-shaped protrusions (height: about 50 μm to 150 μm) may be formed on the skin surface side of the bioadhesive layer 4. This allows the multiple protrusions to penetrate the skin surface when the bioadhesive layer 4 is applied to the skin surface, thereby promoting the penetration of the active ingredient into the skin tissue (dermal tissue).

(polymer matrix)
The polymer matrix is not particularly limited as long as it is composed of a polymer compound that can form a network structure and form a gel by containing at least water. In the present invention, a polymer compound that can be attached to the skin surface is preferably used. As such a polymer compound, a copolymer of a monofunctional monomer having one ethylenically unsaturated group and a crosslinkable monomer is particularly preferred.
Examples of the monofunctional monomer include (meth)acrylamide monomers, (meth)acrylic acid ester monomers, and monomers such as (meth)acrylic acid or a salt thereof. These monofunctional monomers may be used alone or in combination of two or more kinds.

Specific examples of (meth)acrylamide monomers include N,N-dialkyl(meth)acrylamides such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide; N-alkyl(meth)acrylamides such as N-isopropyl(meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, and N-propyl(meth)acrylamide; N-hydroxyalkyl(meth)acrylamides such as N-hydroxyethyl(meth)acrylamide and N-hydroxymethyl(meth)acrylamide; amino group-containing cationic monomers such as dimethylaminopropyl(meth)acrylamide; sulfonic acid group-containing anionic monomers or salts thereof such as tert-butylacrylamidosulfonic acid; and derivatives thereof.

Specific examples of (meth)acrylic acid ester monomers include (meth)acrylic acid alkyl esters having an alkyl group of 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and tert-butyl (meth)acrylate; alkoxy group-containing (meth)acrylic acid esters, such as 2-methoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, and methoxytriethylene glycol (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters, such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; glycerin mono(meth)acrylate; polyalkylene glycol mono(meth)acrylate, such as polyethylene glycol mono(meth)acrylate; and (meth)acrylic acid esters having an aromatic ring, such as benzyl (meth)acrylate.

Specific examples of (meth)acrylic acid or a salt thereof include acrylic acid, methacrylic acid, sodium acrylate, potassium acrylate, and potassium methacrylate.
In the hydrogel, the total content of the structural units derived from the monofunctional monomer is preferably about 10% by mass or more and about 50% by mass or less, and more preferably about 15% by mass or more and about 45% by mass or less, based on the total mass of the hydrogel. By setting the total content of the structural units derived from the monofunctional monomer in the hydrogel within the above range, the flexibility of the hydrogel can be further improved while maintaining sufficient shape retention of the hydrogel.

Cross-linking monomers include, for example, compounds having two or more polymerizable carbon-carbon double bonds in the molecule. Specific examples of such compounds include divinylbenzene, divinylbiphenyl, N,N'-methylenebis(meth)acrylamide, ethylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polyglycerin di(meth)acrylate, etc. These cross-linking monomers may be used alone or in combination of two or more.

The content of structural units derived from crosslinking monomers in the hydrogel is not particularly limited, as it varies slightly depending on the types of monofunctional monomer and crosslinking monomer used, but is preferably about 0.01% by mass to 0.5% by mass, and more preferably about 0.01% by mass to 0.1% by mass, relative to the total mass of the hydrogel. By setting the content of structural units derived from crosslinking monomers in the hydrogel within the above range, the crosslink density can be sufficiently increased to maintain the shape stability of the gel while preventing or suppressing the gel from becoming too hard.

(Plasticizer)
The plasticizer is a component added for the purpose of imparting water retention (moisture retention) to the hydrogel, suppressing evaporation of water, and maintaining the flexibility of the gel. As such a plasticizer, polyoxyalkylene alkyl ether and/or sugar are preferably used. These compounds are more hydrophobic than polyhydric alcohols, so they can reduce the penetration of water into the hydrogel from the outside and prevent or suppress swelling of the gel.
Specific examples of polyoxyalkylene alkyl ethers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene isostearyl ether; and polyoxypropylene alkyl ethers such as polyoxypropylene lauryl ether, polyoxypropylene stearyl ether, and polyoxypropylene isostearyl ether.

Sugars are classified as monosaccharides, disaccharides or polysaccharides, and one of these may be used alone or two or more of them may be used in combination.
Examples of monosaccharides include xylose, arabinose, glucose, galactose, and mannose.
Examples of disaccharides include sucrose, maltose, cellobiose, and lactose.
Examples of polysaccharides include oligosaccharides such as maltotriose, xylan, starch, cellulose, chitin, chitosan, and the like.
Amino sugars of these sugars and their N-acetylated products can also be used.

The content of the plasticizer is preferably about 10% by mass to about 60% by mass, more preferably about 20% by mass to about 50% by mass, based on the total mass of the hydrogel. By setting the content of the plasticizer in the hydrogel within the above range, it is possible to prevent the plasticizer from bleeding out onto the surface of the gel, stabilize the gel over a long period of time, and maintain the adhesive strength of the gel.
The ratio of the polymer matrix to the plasticizer, in terms of mass ratio, is preferably about 0.25:1 or more and 3:1 or less, and more preferably about 0.45:1 or more and 2.5:1 or less.

(Electrolytes)
The electrolyte is a component that is added for the purpose of imparting electrical conductivity to the hydrogel.
The electrolyte may be, for example, an inorganic salt, an organic salt, a polymeric salt, or a mixture thereof.
Specific examples of inorganic salts include alkali metal halides, alkaline earth metal halides, other metal halides, hypochlorites, chlorites, chlorates, perchlorates, sulfates, carbonates, nitrates, phosphates, ammonium salts, complex salts, and the like.
Specific examples of organic salts include metal salts of carboxylic acids such as acetic acid, benzoic acid, lactic acid, tartaric acid, phthalic acid, succinic acid, adipic acid, and citric acid, metal salts of sulfonic acids, metal salts of amino acids, and organic ammonium salts.
Specific examples of the salts of polymers include salts of poly(meth)acrylic acid, salts of polyvinylsulfonic acid, salts of polytert-butylacrylamidosulfonic acid, salts of polyallylamine, and salts of polyethyleneimine.

The content of the electrolyte is preferably about 0.001% by mass to about 10% by mass, more preferably about 0.1% by mass to about 5% by mass, based on the total mass of the hydrogel. By setting the content of the electrolyte in the hydrogel within the above range, an increase in the impedance (Z) of the hydrogel can be prevented, and sufficient conductivity can be imparted to the hydrogel.
The electrolyte may be added for the purpose of adjusting the pH of the hydrogel, for the purpose of improving the moisture retention performance of the hydrogel, for the purpose of imparting antibacterial properties to the hydrogel, etc.

(Water-soluble polymer)
The water-soluble polymer is a component that is added for the purpose of imparting adhesiveness to the hydrogel.
Examples of the water-soluble polymer include polyvinylpyrrolidone, vinylpyrrolidone copolymer, polyvinyl alcohol, polyacrylic acid, sodium polyacrylate, sodium carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium alginate, dextran, etc. These water-soluble polymers may be used alone or in combination of two or more.
Among these, polyacrylic acid and/or sodium polyacrylate are preferred as the water-soluble polymer because they are excellent in the effect of imparting adhesiveness to the hydrogel.
The content of the water-soluble polymer is preferably about 0.1% by mass or more and 5% by mass or less based on the total mass of the hydrogel.

(Other additives)
Other ingredients such as preservatives, bactericides, anti-rust agents, antioxidants, stabilizers, fragrances, surfactants, colorants, anti-inflammatory agents, vitamins, whitening agents, etc. may be added to the hydrogel as needed, within the scope of not impairing the effects of the present invention. These additives may be used alone or in combination of two or more.
The content of these additives is preferably about 0.01% by mass or more and 10% by mass or less with respect to the total mass of the hydrogel.

Such a hydrogel can be prepared, for example, as follows.
When the polymer matrix is composed of a polymer of a monofunctional monomer and a crosslinkable monomer, it can be easily prepared by copolymerizing the monofunctional monomer and the crosslinkable monomer in a mixture liquid in which the monofunctional monomer, the crosslinkable monomer, and the plasticizer are uniformly mixed and dissolved in water.
If necessary, a water-soluble polymer, an electrolyte and/or other additives may be added to the mixture liquid.
Alternatively, the polymer matrix may be formed in advance by polymerizing a monofunctional monomer and a crosslinkable monomer, and then impregnated with water and a plasticizer, and, if necessary, with a water-soluble polymer, an electrolyte, and/or other additives.

The polymerization of the monofunctional monomer and the crosslinkable monomer is preferably carried out in the presence of a polymerization initiator, such as a thermal polymerization initiator or a photopolymerization initiator.
As the thermal polymerization initiator, a compound that is cleaved by heat to generate radicals can be used. Examples of such thermal polymerization initiators include benzoyl peroxide, azobiscyanovaleric acid, azobisisobutyronitrile, azobisamidinopropane dihydrochloride, potassium persulfate, ammonium persulfate, etc. These thermal polymerization initiators may be used alone or in combination of two or more.
If necessary, a redox initiator consisting of a reducing agent such as ferrous sulfate or pyrosulfite and a peroxide such as hydrogen peroxide, sodium thiosulfate or peroxodisulfate may be used in combination with the thermal polymerization initiator.

As the photopolymerization initiator, a compound that is cleaved by ultraviolet or visible light to generate radicals can be used, for example, azo-based polymerization initiators such as 2,2'-azobis-N-(2-hydroxyethyl)propionamide and 2,2'-azobis(1-imino-1-pyrrolidino-2-methylpropane)dihydrochloride, α-hydroxyketones, α-aminoketones, benzyl methyl ketal, bisacylphosphine oxides, metallocenes, etc.
Specific examples of the photopolymerization initiator include 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1-[(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, etc. These photopolymerization initiators may be used alone or in combination of two or more.

The content of the polymerization initiator is preferably about 0.01% by mass or more and 1% by mass or less, more preferably about 0.05% by mass or more and 0.5% by mass or less, based on the total mass of the hydrogel (total mass of the material for forming the bioadhesive layer). By setting the content of the polymerization initiator in the hydrogel within the above range, the polymerization reaction can be sufficiently advanced, and the amount of monofunctional monomer and crosslinking monomer remaining in the obtained hydrogel can be reduced. In addition, discoloration (yellowing) and odor caused by the polymerization initiator remaining in the obtained hydrogel can be prevented.
The thickness of the bioadhesive layer 4 is not particularly limited, but from the viewpoint of ensuring high conformability of the conductive sheet 1 to the skin surface and the mechanical strength of the bioadhesive layer 4, it is preferably approximately 50 μm or more and 500 μm or less, and more preferably approximately 100 μm or more and 350 μm or less.

The bioadhesive layer 4 is not limited to a configuration that covers the entire conductive pattern 3, but may be a configuration that covers only a part of the conductive pattern 3. In the latter case, the conductive sheet 1 is attached such that the conductive pattern 3 is in direct contact with the skin surface in the portion where the bioadhesive layer 4 is not present, and the bioadhesive layer 4 is in direct contact with the skin in the portion where the bioadhesive layer 4 is present. In this case, the presence of the bioadhesive layer 4 reliably maintains the state where the conductive sheet 1 is attached to the skin surface of the user, while a stronger current can be used to provide muscle stimulation to the skin surface where the conductive pattern 3 is in direct contact.
Furthermore, it is sufficient that at least a part of the conductive sheet 1 is stretchable in any direction. Therefore, the conductive sheet 1 may be in an embodiment in which the sheet base material 2 is stretchable but the conductive pattern 3 is not necessarily stretchable, or in which the sheet base material 2 and/or the conductive pattern 3 include stretchable and non-stretchable parts, such that the conductive sheet 1 as a whole includes stretchable and non-stretchable parts.
Furthermore, the conductive sheet 1 may be configured not to have stretchability, but at least a part of it may have flexibility capable of conforming to the skin surface. In this case, the range of materials to be used for the sheet base material 2 and the conductive pattern 3 can be expanded.

The device body 10 is attached to such a conductive sheet 1 .
In the first configuration example, the conductive sheet 1 has an elongated shape, and the device body 10 is attached to the central portion (narrow portion 22) of the conductive sheet 1 in the longitudinal direction.
As described above, a pair of pins 101 and a pair of terminal portions 11 protrude from the back surface of the device body 10. The pair of pins 101 are each inserted into corresponding through holes 221 formed in the narrow portion 22 of the sheet base material 2. The pair of terminal portions 11 are each inserted into corresponding openings 222 formed in the narrow portion 22 of the sheet base material 2. In this way, the device body 10 is connected (fixed) to the conductive sheet 1.

With this configuration, in this embodiment, the device body 10 is detachably attached to the conductive sheet 1. Note that the device body 10 may also be fixed to the conductive sheet 1 so as not to be detachable.
When the device body 10 is configured to be detachable from the conductive sheet 1, the device body 10 is preferably attached to the conductive sheet 1 by magnetic force. For example, by disposing a permanent magnet inside the device body 10 or on the back surface, the permanent magnet can be attracted to the conductive pattern 3 by magnetic force. Such an attachment/detachment mechanism has a simple configuration and also contributes to preventing the device body 10 from becoming large.
Furthermore, when the device main body 10 is configured to be attracted to the conductive sheet 1 by magnetic force, permanent magnets of opposite polarity (south pole and north pole) can be placed on both the device main body 10 and the conductive sheet 1, thereby preventing the device main body 10 from being attached in the opposite direction to the conductive sheet 1.
The device body 10 may be configured to be attached to an end in the longitudinal direction of the conductive sheet 1. In this case, the wiring portion 31 is extended to the end of the sheet base material 2, and the connection portion 34 is connected to the tip of the wiring portion 31. This configuration can also be adopted for conductive sheets 1 of other configurations and the conductive sheet 1 of the second configuration example described later.

Furthermore, it is desirable for the device main body 10 to be as small as possible, and the mass must be such that it does not interfere with the close contact with the skin surface. For this reason, the device main body 10 uses a flexible substrate to reduce its weight and size.
In this case, it is preferable that the skin treatment device 100 includes a plurality of different types of conductive sheets 1, and the device body 10 is detachably attached to each conductive sheet 1. This allows the appropriate conductive sheet 1 to be selected and used depending on the area of the skin surface to be treated, making it easier to more reliably perform skin treatment according to the user's requirements. A second configuration example of the conductive sheet 1 will be described later.

As shown in Fig. 5, two operation buttons 12 are provided on the surface of the device main body 10. These operation buttons 12 can change at least one of the amount of power supply or the supply pattern (mode). Note that changing the amount of power supply also includes turning the power supply (power source) on and off.
Further, a power supply unit 13, a control unit 14, and an electric circuit unit 15 are provided inside the device main body 10. The power supply unit 13, the electric circuit unit 15, and the two operation buttons 12 are electrically connected to the control unit 14, and the two terminal units 11 are electrically connected to the electric circuit unit 15.
The power supply unit 13 is configured to supply power to the electrode unit 32. For example, a dry cell, a solar cell, a fuel cell, a lithium ion secondary battery, an all-solid-state battery, a lithium polymer battery, etc. can be used as the power supply unit 13. The power supply unit 13 may be a connector to which a power cable can be connected.

The control unit 14 includes a processing element and a storage element.
The arithmetic element is composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc. The arithmetic element realizes various functions related to the skin processing device 100 by reading out a predetermined program stored in the memory element. That is, information processing by the software stored in the memory element is specifically realized by the arithmetic element.
The number of arithmetic elements is not limited to one, and a plurality of arithmetic elements may be provided for each function, or a combination thereof may be used.

The memory element stores various pieces of information defined in the above description. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs related to the skin processing device 100 executed by the computing element, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to the computation of the programs.
The storage element also stores various programs, variables, and the like related to the skin processing device 100 that are executed by the arithmetic element.

The electric circuit section 15 includes, for example, a drive circuit, an output waveform generating circuit, a transformer, a switching circuit, and the like.
The control unit 14 is configured to control the power supplied from the power supply unit 13 to the electrode unit 32 via the electric circuit unit 15. Here, controlling the power means setting at least one of the voltage value, the current value, the waveform, the frequency, the pulse width, the current direction, and the current flow time.
In this embodiment, the current supplied by the device main body 10 under the control of the control unit 14 is at least one of a current that promotes the penetration of the active ingredients contained in the topical skin preparation, a current that provides muscle stimulation, a current that warms the skin surface, and a microcurrent.
The type (mode) of current supplied by the device main body 10 can be changed by operating the operation button 12 .

It is preferable to use currents having multiple types of pulse waveforms in combination as the current for promoting the penetration of the active ingredient contained in the topical skin preparation, which allows the active ingredient contained in the topical skin preparation to penetrate into skin tissue more quickly.
For example, the current having the first pulse waveform preferably has a frequency of about 1.5 kHz ±10% and a voltage of about 20 V or less. In this case, it is more preferable to generate one pulse with reversed polarity for every multiple (e.g., seven) pulses of the same polarity.
Moreover, it is preferable that the current having the second pulse waveform has a frequency of about 1 Hz or more and 1 kHz or less, and a voltage of about 20 V or more and 50 V or less.

The order in which these two types of currents are applied to the skin surface is arbitrary, but it is preferable that they be alternated.
It should be noted that the combination of electric currents is not limited to these, and it is preferable to combine stimuli depending on the purpose, the ingredients to be penetrated, and the user's preference for sensation to promote the penetration of the active ingredients contained in the topical skin preparation.
For example, a current having a third pulse waveform may be used. In this case, the current preferably has a frequency of about 10 Hz to 100 Hz and a voltage of about 50 V or more.
By combining a current having the first pulse waveform with a current having the third pulse waveform, the device can be used in a manner that causes a mild irritating sensation even when worn on the skin.

In addition, the current having multiple types of pulse waveforms may include a current having a frequency of about 10 Hz or more and 50 Hz or less (myogenic potential stimulation), a current having a frequency of 1 kHz, and a current having multiple frequencies.
In addition, the current that promotes the penetration of the active ingredient contained in the topical skin preparation is not limited to the combined use of currents having multiple types of pulse waveforms, and a current having a single waveform for iontophoresis may be used alone, or may be used in combination with a current having at least one arbitrary pulse waveform.

The current for applying the muscle stimulation EMS (Electrical Muscle Stimulation) preferably has a frequency of about 1 Hz to 1 kHz, which causes muscle contraction to cause muscle movement and relieve tension.
The frequency of the current (high frequency current) for heating the skin surface is preferably about 10 kHz or more, and more preferably about 10 kHz or more and 500 kHz or less.
The frequency of the microcurrent is preferably about 1200 Hz or less.

The active ingredients contained in the external skin preparation used with the skin treatment device 100 include the following compounds.
Specific examples of active ingredients include tranexamic acid or a derivative thereof (e.g., cetyl tranexamate hydrochloride), niacinamide, pyridoxine hydrochloride or a derivative thereof, benzalkonium chloride, palmitoyl tripeptide-5, acetyl hexapeptide-8, dipeptide diaminobutyroylbenzylamide diacetate or a derivative thereof, allantoin, aldioxa, carnitine HCl, urea, and the like.

Other specific examples of active ingredients include potassium 4-methoxysalicylate, disodium adenosine monophosphate, ascorbic acid or its derivatives (L-ascorbic acid 2-glucoside, sodium L-ascorbyl phosphate, disodium L-ascorbyl sulfate, trisodium ascorbyl palmitate phosphate, etc.), sodium dl-α tocopheryl phosphate, zinc paraphenolsulfonate, salicylic acid and its sodium salts, sodium lactate, sodium L- or DL-pyrrolidone carboxylate, sodium L-glutamate, sodium L-aspartate, glycyrrhizic acid or its salts (dipotassium glycyrrhizinate, ammonium glycyrrhizinate, etc.), sodium guaiazulene sulfonate, sodium dilauroyl glutamate lysine, etc.

Other examples of active ingredients include kojic acid, arbutin, hydroquinone, 4-n-butylresorcinol, 5,5'-dipropyl-biphenyl-2,2'-diol, ellagic acid, ascorbic acid derivatives (3-O-ethyl ascorbic acid, 3-glyceryl ascorbic acid, bisglyceryl ascorbic acid, hexyl 3-glyceryl ascorbic acid, myristyl 3-glyceryl ascorbic acid, 3-lauryl glyceryl ascorbic acid, etc.), D-pantothenyl alcohol, cholecalciferol, 3-o-cymen-5-ol (isopropylmethylphenol), glycine, proline, alanine, serine, acetylhydroxyproline, ε-aminocaproic acid, γ-aminobutyric acid, trimethylglycine, xylose, sorbitol, mannitol, butylene glycol, hexylene glycol, pentylene glycol, glycerin, and hinokitiol.

Other specific examples of active ingredients include fullerene, oryzanol, ceramide EOP, ceramide EOS, ceramide NG, caproyl sphingosine, ceramide NP, N-stearoyl phytosphingosine, N-stearoyl dihydrosphingosine, ceramide AG, ceramide AP, hydroxystearyl phytosphingosine, ceramide 6II, phytosphingosine (whether or not encapsulated in liposomes), flavonoids (isoflavones, licorice root extract, licorice flavonoids, liquorice flavonoids, etc.), extracts obtained from plants or animals (chamomilla ET, sophora flavonoids, Swertia japonica extract, carrot or its root extract, soybean extract, soybean seed extract, tea leaf extract, Galactomyces culture medium, rice extract No. 11, astaxanthin liquid, red algae extract, placenta extract, etc.), stem cell culture medium, stem cell culture supernatant, etc.

Other examples of active ingredients include squalane, linoleic acid, ascorbyl tetra-2-hexyldecanoate, ascorbyl dipalmitate, retinol or its derivatives (retinol acetate, retinol palmitate, hydrogenated retinol, retinol linoleate, etc.), tocopherol (natural vitamin E) or its derivatives (tocopherol nicotinate, dl-α-tocopherol, d-δ-tocopherol, DL-α-tocopherol acetate, etc.), stearyl glycyrrhetinate, estradiol, ethinyl estradiol, astaxanthin, rice germ oil, phospholipids (sphingomyelin, etc.), synthetic or vegetable squalane, guaiazulene, guaiazulene sulfonate, fatty acid esters of ascorbic acid (ascorbyl stearate, ascorbyl palmitate, etc.), di(phytosteryl/octyldodecyl) lauroyl glutamate, and oil-soluble placenta.

Other specific examples of active ingredients include human recombinant oligopeptide-1, palmitoyl hexapeptides (palmitoyl hexapeptide-4, etc.), palmitoyl pentapeptides, hydrolyzed collagen or a derivative thereof, hyaluronic acid or a derivative thereof (sodium hyaluronate, sodium acetylated hyaluronate), Tremella fuciformis polysaccharide, Alcaligenes-produced polysaccharide, polyquaterniums, and the like.
The bioadhesive layer 4 as described above can retain the above-mentioned compounds well.

In addition, the current that promotes the penetration of the active ingredient contained in the skin topical preparation may be an alternating current. For example, depending on the characteristics of the active ingredient, an alternating current (alternating current stimulation) of a suitable frequency may be applied to the skin surface to promote the penetration of the active ingredient.
When the active ingredient is a low molecular weight substance that is water soluble and easily becomes positively charged in an aqueous solution (tranexamic acid, etc.), the frequency of the alternating current is preferably about 10 kHz or more and 200 kHz or less, and more preferably about 50 kHz or more and 180 kHz or less.
When the active ingredient is a low molecular weight substance that is water soluble and tends to be negatively charged in an aqueous solution (such as potassium 4-methoxysalicylic acid), the frequency of the alternating current is preferably about 10 kHz or more and 200 kHz or less, and more preferably about 50 kHz or more and 160 kHz or less.

In addition, depending on the properties of the active ingredient, it may be possible to promote the penetration of the active ingredient into skin tissue by providing an appropriate stimulus, such as when the active ingredient is a low molecular weight substance that is water-soluble and has almost no charge in an aqueous solution (kojic acid, arbutin, etc.) or an ampholyte (amino acids, peptides), a lipid or oil-soluble substance (squalane, etc.), or a polymeric substance (human recombinant oligopeptide-1, etc.).

6 and 7, the bioadhesive layer 4 may be provided so as to correspond to the shape in plan view of the conductive pattern 3. Specifically, the shape in plan view of the bioadhesive layer 4 may be the same as the shape in plan view of the conductive pattern 3, or may be set to be slightly larger.
Fig. 6 is a plan view showing an exploded state of a conductive sheet having a bioadhesive layer of another configuration, and Fig. 7 is a cross-sectional view of the conductive sheet of Fig. 6 corresponding to Fig. 4.
In the following description, the front side of the paper in FIG. 6 will also be referred to as the "front" or "top", the back side of the paper in FIG. 6 will also be referred to as the "back" or "bottom", the upper side in FIG. 7 will also be referred to as the "front" or "top", and the lower side in FIG. 7 will also be referred to as the "back" or "bottom".

According to this configuration, when a topical skin preparation is used in combination, the topical skin preparation can be held in the slits 3a of the conductive pattern 3 and the slits 4a of the bioadhesive layer 4, and prevented or suppressed from scattering. In this state, if a current that promotes the penetration of the active ingredient contained in the topical skin preparation is supplied to the skin surface via the electrode section 32, the penetration efficiency of the active ingredient can be further increased.
In the skin treatment device 100, when the area of the conductive sheet 1 in a plan view is A [ ^mm2 ] and the area of the device body 10 in a plan view is B [ ^mm2 ], it is preferable that B/A is about 0.1 to 0.6, and more preferably about 0.2 to 0.5. This allows the size of the conductive sheet 1 and the size of the device body 10 to be balanced.
In addition, the bioadhesive layer 4 does not have to be arranged to correspond to the shape of the conductive pattern 3 in a planar view, and may, for example, have a shape and/or size that covers the entire conductive pattern 3, or may have a shape and/or size that exposes a portion of the conductive pattern 3.

<Second Configuration Example>
Next, a second configuration example of the conductive sheet 1 will be described.
Hereinafter, the conductive sheet 1 of the second configuration example will be described, focusing on the differences from the conductive sheet 1 of the first configuration example described above, and a description of similar points will be omitted.
FIG. 8 is a plan view showing an exploded state of a skin treatment device including a conductive sheet of the second configuration example.
In the following description, the front side of the paper in Fig. 8 will be referred to as the "front" or "top", and the back side of the paper in Fig. 8 will be referred to as the "back" or "bottom". In Fig. 8, the conductive pattern 3 located on the back side (lower side) of the sheet base material 2 is shown with oblique lines.

The conductive sheet 1 of the second configuration example is elongated and is formed so that the width of one end side is larger than the width of the other end side. The device body 10 is configured to be attached to the one end side of the conductive sheet 1.
Moreover, the conductive sheet 1 is curved midway in the longitudinal direction.
The conductive sheet 1 having such a configuration can be suitably used by being attached to the skin areas around the eyes and where nasolabial folds are prominent.
In this way, an appropriate conductive sheet 1 can be selected depending on the area of the skin surface to be treated, and the device main body 10 can be attached and used, making it easier to more reliably perform skin treatment according to the user's needs.

<Third Configuration Example>
Next, a third configuration example of the conductive sheet 1 will be described.
Hereinafter, the conductive sheet 1 of the third configuration example will be described, focusing on the differences from the conductive sheets 1 of the first and second configuration examples, and a description of similar points will be omitted.
FIG. 9 is a plan view showing a conductive sheet 1 according to a third configuration example.
In the following description, the front side of the paper in Fig. 9 will be referred to as the "front" or "top", and the back side of the paper in Fig. 9 will be referred to as the "back" or "bottom". In Fig. 9, the conductive pattern 3 located on the back side (lower side) of the sheet base material 2 is shown with diagonal lines.

The conductive sheet 1 of the third configuration example has an elongated shape and is curved midway in the longitudinal direction to form a C-shape or an L-shape.
The conductive sheet 1 having such a configuration can be brought into contact with, for example, the areas of the frontalis muscle, temporalis muscle, and orbicularis oculi muscle all at once, making it easy to perform skin treatment on those areas.
Moreover, the tip 35 of each conductive pattern 3 on the opposite side to the connection portion 34 is formed in a mesh shape. By having the tip 35 in such a shape, it is possible to disperse the current applied to the skin surface in that portion (in other words, to prevent the current from concentrating). As a result, the user can obtain a mild physical sensation (muscle stimulation), i.e., a physical sensation that is not unpleasant.

<Fourth Configuration Example>
Next, a fourth configuration example of the conductive sheet 1 will be described.
Hereinafter, the conductive sheet 1 of the fourth configuration example will be described, focusing on the differences from the conductive sheets 1 of the first to third configuration examples, and a description of similar points will be omitted.
FIG. 10 is a plan view showing a conductive sheet 1 according to a fourth configuration example.
In the following description, the front side of the paper in Fig. 10 will be referred to as the "front" or "top", and the back side of the paper in Fig. 10 will be referred to as the "back" or "bottom". In Fig. 10, the conductive pattern 3 located on the back side (lower side) of the sheet base material 2 is shown with diagonal lines.

The conductive sheet 1 of the fourth configuration example is different in the configuration of the tip portion of one of the conductive patterns 3, but is otherwise similar to the conductive sheet 1 of the third configuration example.
That is, in the conductive sheet 1 of the fourth configuration example, the tip portion 35a of one of the conductive patterns 3 is separated and independent. Therefore, electricity cannot flow to the tip portion 35a, and therefore, no current is supplied from the tip portion 35a to the skin surface.
In this case, since the current is not supplied across the frontalis muscle and the temporalis muscle, the occurrence of pain can be reduced.

<Fifth Configuration Example>
Next, a fifth configuration example of the conductive sheet 1 will be described.
Hereinafter, the conductive sheet 1 of the fifth configuration example will be described, focusing on the differences from the conductive sheets 1 of the first to fourth configuration examples, and a description of similar points will be omitted.
FIG. 11 is a bottom view showing the conductive sheet 1 of the fifth configuration example.
In the following description, the front side of the paper in Fig. 11 will be referred to as the "back" or "bottom", and the back side of the paper in Fig. 11 will be referred to as the "front" or "top". Furthermore, the bioadhesive layer 4 is omitted in Fig. 11.
The conductive sheet 1 of the fifth configuration example includes a masking portion 5 provided so as to cover a portion of the sheet substrate 2 (conductive pattern 3), but is otherwise similar to the conductive sheet 1 of the fourth configuration example.

This masking portion 5 has at least one of a function of blocking the current supplied to the skin surface of the user and a function of reducing the elasticity of the conductive sheet 1 .
For example, as shown in Fig. 11, the masking portion 5 can be made of an insulating sheet provided so as to cover a portion close to the connection portion 34 of one of the conductive patterns 3. With this configuration, it is possible to cut off the current supplied to the skin surface from the vicinity of the connection portion 34, and to preferentially supply the current to the skin surface from the tip portion 35. In this way, by changing the portion of the conductive pattern 3 covered by the masking portion 5, it is possible to adjust the position where the bodily sensation (muscle stimulation) is easily obtained.

The masking portion 5 can also be made of a low-elasticity sheet. In this case, the conductive sheet 1 can have an elastic portion that is pulled to attach to the skin surface, and a non-elastic portion that stably secures the positional relationship between the skin surface and the conductive pattern 3.
In this case, the elastic portion may be a portion that needs to conform to the shape of the face (e.g., a portion that corresponds to a skin surface that is prone to wrinkles, etc.), whereas the non-elastic portion may be a portion where muscle stimulation is desired to be reliably applied, etc.

<Sixth Configuration Example>
Next, a sixth configuration example of the conductive sheet 1 will be described.
Hereinafter, the conductive sheet 1 of the sixth configuration example will be described, focusing on the differences from the conductive sheets 1 of the first to fifth configuration examples, and a description of similar points will be omitted.
Fig. 12(a) is a plan view showing the conductive sheet 1 of the sixth configuration example, and Fig. 12(b) is a side view showing the conductive sheet 1 of the sixth configuration example. Fig. 13 is a cross-sectional view taken along line BB in Fig. 12(a).
In the following description, the front side of the paper in FIG. 12(a) is also referred to as "front" or "top", the back side of the paper in FIG. 12(a) is also referred to as "back" or "bottom", the upper side in FIG. 12(b) is also referred to as "front" or "top", and the lower side in FIG. 12(b) is also referred to as "back" or "bottom". The upper side in FIG. 13 is also referred to as "front" or "top", and the lower side in FIG. 13 is also referred to as "back" or "bottom". In FIG. 12, the conductive pattern 3 and the like located on the back side (lower side) of the sheet base material 2 are shown by dashed lines.

13, the sheet base material 2 of the sixth configuration example has a non-stretchable sheet base material 201 and a stretchable sheet base material 202, which are integrally formed. The sheet base material 2 may be formed by separately producing the non-stretchable sheet base material 201 and the stretchable sheet base material 202, and then bonding them together, for example, by adhesion with an adhesive, fusion (thermal fusion, high-frequency fusion, ultrasonic fusion), an adhesive member, etc. As the adhesive member, for example, an adhesive sheet 6, a conductive tape 37, and/or an additional adhesive tape can be used.
It is preferable that the non-elastic sheet substrate 201 is relatively hard. The material of the non-elastic sheet substrate 201 is not particularly limited, but examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyphenylene sulfide (PPS), and fluororesin.
Furthermore, the non-stretchable sheet substrate 201 has two through holes 2011 formed therein.

A reinforcing block 24 is fixed to the upper surface of the non-stretchable sheet substrate 201 .
Two through holes 241 are formed in the reinforcement block 24, and each of them opens at the opening 222. Each of the through holes 241 communicates with each of the through holes 2011. In addition, two through holes 221 are formed in predetermined positions of the reinforcement block 24. The device body 10 is attached to this reinforcement block 24.
The reinforcing block 24 may be made of the same materials as those listed for the non-stretchable sheet substrate 201 .
The stretchable sheet substrate 202 has high conformability to the skin surface and can accommodate the movement of the skin, and is therefore excellent for supporting the conductive pattern 3 as the skin electrode. The stretchable sheet substrate 202 can be made of the same materials as those listed for the sheet substrate 2.

Two conductive patterns 3 are provided on the lower surface of the stretchable sheet substrate 202. A conductive tape 37 is connected to each of the two conductive patterns 3 at an electrical connection portion 38.
The conductive tape 37 may be made of a resin tape in which conductive particles containing silver, gold, nickel, etc. are dispersed. Furthermore, a columnar connection portion 36 is fixed to the upper surface of each conductive tape 37. The connection portion 36 is preferably magnetic.
An adhesive tape 6 is provided between each conductive tape 37 and the sheet base material 2. A through hole 61 is formed in the adhesive tape 6. Examples of the constituent material of the adhesive tape 6 include an acrylic adhesive, a urethane adhesive, a silicone adhesive, a natural rubber adhesive, and a synthetic rubber adhesive. These adhesives may be used alone or in combination of two or more.

When the conductive sheet 1 is in an assembled state, the connection portion 36 is inserted into the through hole 241 via the through hole 61 and the through hole 2011 .
A masking tape 7 is provided on the lower surface of the conductive tape 37. The masking tape 7 may be made of the same materials as those listed for the non-stretchable sheet substrate 201.
The conductive sheet 1 has a bioadhesive layer 4 formed on the bottom surface thereof.
According to this configuration, the connection portion 36 that electrically connects the terminal portion 11 of the device body 10 is reinforced with the non-elastic sheet substrate 201, the reinforcing block 24, and the masking tape 7, so that a stable connection between the conductive sheet 1 and the device body 10 is possible. Also, the device body 10 can be easily removed from the conductive sheet 1. Meanwhile, the conductive pattern 3 is supported by the elastic sheet substrate 202, so that it is attached with high conformability to the skin surface.

When the conductive sheets 1 of the second to sixth configuration examples were applied to the area around the eyes for 10 minutes a day, three times a week, after four weeks of use, the thickness of the orbicularis oculi and temporalis muscles significantly increased, and after eight weeks of use, significant improvements were observed in the moisture content and sagging under the eyes.
Age-related changes in the eyes include sagging above and below the eyes, wrinkles around the eyes, etc. It is known that the causes of these age-related changes are not only physiological aging and photoaging, but also the skin and muscles around the eyes.
It has been reported that the orbicularis oculi muscle, which surrounds the eye in a doughnut shape, becomes thinner with age, and it is known that as the eye area droops, a youthful appearance is lost and changes that make one feel older occur.
It was found that the conductive sheet 1, which easily fits around the eyes, can be used to efficiently apply electrical stimulation to the muscles around the eyes, thereby strengthening the orbicularis oculi and temporalis muscles, thereby significantly improving sagging around the eyes.

Next, the conductive sheet of the present invention will be described.
The conductive sheet 1 is used to supply an electric current to the skin surface of a user, and at least a part of it is stretchable in any direction, or at least a part of it has flexibility to conform to the skin surface. The conductive sheet 1 has a sheet base material 2, a conductive pattern 3, and a bioadhesive layer 4. The conductive pattern 3 is provided on one surface of the sheet base material 2, and includes a wiring section 31 and an electrode section 32 connected to one end of the wiring section 31. The bioadhesive layer 4 is provided on the opposite side of the conductive pattern 3 to the sheet base material 2, and is configured to be attached to the skin surface of a user. In addition, the bioadhesive layer 4 is preferably in a gel form.
The configurations of the sheet substrate 2, the conductive pattern 3 and the biological adhesive layer 4 are similar to those of the sheet substrate 2, the conductive pattern 3 and the biological adhesive layer 4 described in the skin treatment device of the present invention, respectively.
By using such a conductive sheet 1, skin treatment can be performed on the skin surface in various areas according to the needs of the user.
Furthermore, it may be provided in the following aspects:

(1) A skin treatment device comprising: a conductive sheet, at least a portion of which is stretchable in any direction, or a conductive sheet, at least a portion of which is flexible enough to conform to the skin surface; and a device body that is attached to the conductive sheet and supplies an electric current to the skin surface of a user, the conductive sheet having a sheet base material, a conductive pattern, and a bioadhesive layer, the conductive pattern being provided on one side of the sheet base material and comprising a wiring section and an electrode section connected to one end of the wiring section, the bioadhesive layer being provided on the side of the conductive pattern opposite the sheet base material and configured to be attached to the skin surface of the user.

(2) A skin treatment device as described in (1) above, in which the bioadhesive layer is in a gel state.

(3) A skin treatment device according to (1) or (2) above, wherein the electric current is at least one of a current that promotes the penetration of an active ingredient contained in a skin topical agent, a current that provides muscle stimulation, a current that warms the skin surface, and a microcurrent.

(4) A skin treatment device according to any one of (1) to (3) above, wherein the device body is removably attached to the conductive sheet.

(5) A skin treatment device according to any one of (1) to (4) above, wherein the device body is attached to the conductive sheet by magnetic force.

(6) A skin treatment device according to (4) or (5) above, comprising a plurality of different types of conductive sheets, and the device body is removably attached to each of the conductive sheets.

(7) A skin treatment device according to any one of (4) to (6) above, further comprising a positioning portion for the conductive sheet of the device body.

(8) A skin treatment device according to any one of (1) to (7) above, wherein the device body further has a pair of terminal portions, and the wiring portion has a connection portion at the other end thereof that is connected to one of the terminal portions.

(9) A skin treatment device as described in (8) above, wherein the sheet base material has an opening that exposes the connection portion.

(10) A skin treatment device according to any one of (1) to (9) above, wherein the wiring section and a portion of the electrode section are arranged along the outer edge of the sheet substrate.

(11) A skin treatment device according to any one of (1) to (10) above, wherein the conductive sheet is elongated, and the device body is attached to the center or end of the conductive sheet in the longitudinal direction.

(12) A skin treatment device according to any one of (1) to (10) above, wherein the conductive sheet is elongated and is formed so that the width of one end is greater than the width of the other end, and the device body is attached to the one end of the conductive sheet.

(13) A skin treatment device according to (11) or (12) above, in which the conductive sheet is curved midway along its longitudinal direction.

(14) A skin treatment device as described in (13) above, in which the conductive sheet is C-shaped or L-shaped.

(15) In the skin treatment device described in any one of (1) to (14) above, when the area of the conductive sheet in a planar view is A [mm ² ] and the area of the device body in a planar view is B [mm ² ], B/A is 0.1 or more and 0.6 or less.

(16) A skin treatment device according to any one of (1) to (15) above, wherein the bioadhesive layer is provided to correspond to the shape of the conductive pattern in a planar view.

(17) A skin treatment device according to any one of (1) to (16) above, wherein the resistance of the entire conductive pattern and the bioadhesive layer, or the conductive pattern alone, when not stretched, is 1000 Ω or less.

(18) A skin treatment device according to any one of (1) to (17) above, wherein the conductive sheet further includes a masking portion arranged to cover a portion of the sheet base material, and the masking portion has at least one of the functions of blocking the current supplied to the skin surface of the user and reducing the elasticity of the conductive sheet.

(19) A conductive sheet used to supply electric current to the skin surface of a user, at least a portion of which is stretchable in any direction, or at least a portion of which is flexible enough to conform to the skin surface, the conductive sheet having a sheet base material, a conductive pattern, and a bioadhesive layer, the conductive pattern being provided on one side of the sheet base material and including a wiring section and an electrode section connected to one end of the wiring section, the bioadhesive layer being provided on the side of the conductive pattern opposite the sheet base material, and configured to be attached to the skin surface of the user.

(20) The conductive sheet according to (19) above, wherein the bioadhesive layer is in a gel state.
Of course, this is not the case.

As described above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and modifications thereof are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.
In other words, the present invention is not limited to the above-described embodiments, but can be implemented in a suitable shape and treatment method depending on the wrinkles on the skin surface, the shape of the skin surface at the application position, the skin condition, and the active ingredients used.

For example, a film heater may be disposed between the sheet substrate 2 and the bioadhesive layer 4. In this case, if a part of the conductive pattern 3 and a part of the film heater are electrically connected, a current (power) can be supplied to the film heater. This allows the skin treatment device 100 to achieve a warming effect on the skin surface by heating the film heater when in use.
A magnetic layer may be disposed between the sheet substrate 2 and the bioadhesive layer 4. In this case, if a part of the conductive pattern 3 and a part of the magnetic layer are electrically connected, a current (power) can be supplied to the magnetic layer. This allows the magnetic force of the magnetic layer to exert a blood circulation promoting effect on the skin surface when the skin treatment device 100 is used. Such a magnetic layer can be created by printing magnetic ink or by forming a pattern containing magnetic powder.
Furthermore, a magnetic conductive filler may be used to form a magnetic conductive pattern 3 .

Furthermore, the configurations of the conductive sheet 1 and the device body 10 are not limited to the above-mentioned embodiments. For example, the device body 10 may be provided with multiple terminal portions (power contacts) 11 so that a current (power) can be supplied from one device body 10 to multiple conductive sheets 1.

100: Skin treatment device, 1: Conductive sheet, 2: Sheet base material, 201: Non-elastic sheet base material, 2011: Through hole, 202: Stretchable sheet base material, 21: Wide section, 22: Narrow section, 221: Through hole, 222: Opening, 23: Ear section, 24: Reinforcement block, 241: Through hole, 3: Conductive pattern, 3a: Slit, 31: Wiring section, 32: Electrode section, 33: Junction section , 34: Connection part, 35: Tip part, 35a: Tip part, 36: Connection part, 37: Conductive tape, 38: Electrical connection part, 4: Bioadhesive layer, 4a: Slit, 5: Masking part, 6: Adhesive tape, 61: Through hole, 7: Masking tape, 10: Device body, 101: Pin, 11: Terminal part, 12: Operation button, 13: Power supply part, 14: Control part, 15: Electrical circuit part

Claims

A skin treatment device, comprising:
A conductive sheet at least a part of which is stretchable in any direction, or a conductive sheet at least a part of which has flexibility so that it can conform to the skin surface, and a device body that is attached to the conductive sheet and supplies an electric current to the skin surface of a user,
The conductive sheet has a sheet base material, a conductive pattern, and a bioadhesive layer,
the conductive pattern is provided on one surface of the sheet base material and includes a wiring portion and an electrode portion connected to one end of the wiring portion;
The bioadhesive layer is provided on the opposite side of the conductive pattern to the sheet substrate, and is configured to be attached to the skin surface of the user.
The skin treatment device according to claim 1,
The skin treatment device, wherein the bioadhesive layer is in a gel state.
The skin treatment device according to claim 1 or 2,
The current is at least one of a current that promotes the penetration of an active ingredient contained in a skin topical preparation, a current that imparts muscle stimulation, a current that warms the skin surface, and a microcurrent.
In the skin treatment device according to any one of claims 1 to 3,
The device body is a skin treatment device that is detachably attached to the conductive sheet.
In the skin treatment device according to any one of claims 1 to 4,
The device body is attached to the conductive sheet by magnetic force.
The skin treatment device according to claim 4 or 5,
A plurality of different types of conductive sheets are provided,
The device body is detachably attached to each of the conductive sheets.
The skin treatment device according to any one of claims 4 to 6,
The skin treatment device further comprises a positioning portion of the device body relative to the conductive sheet.
The skin treatment device according to any one of claims 1 to 7,
The device body further has a pair of terminal portions,
The wiring portion has a connection portion at the other end thereof that is connected to one of the terminal portions, the skin treatment device.
The skin treatment device according to claim 8,
The sheet base material has an opening through which the connection portion is exposed.
The skin treatment device according to any one of claims 1 to 9,
A skin treatment device, wherein the wiring portion and a portion of the electrode portion are arranged along an outer edge of the sheet base material.
The skin treatment device according to any one of claims 1 to 10,
The conductive sheet has an elongated shape,
The device body is attached to the center or end of the conductive sheet in the longitudinal direction of the skin treatment device.
The skin treatment device according to any one of claims 1 to 10,
The conductive sheet is elongated and is formed so that the width of one end side is larger than the width of the other end side,
The device body is a skin treatment device attached to the one end side of the conductive sheet.
13. The skin treatment device according to claim 11 or 12,
A skin treatment device, wherein the conductive sheet is curved midway in its longitudinal direction.
The skin treatment device according to claim 13,
The conductive sheet is C-shaped or L-shaped.
The skin treatment device according to any one of claims 1 to 14,
When the area of the conductive sheet in a planar view is A [mm 2 ] and the area of the device body in a planar view is B [mm 2 ], B/A is 0.1 or more and 0.6 or less.
The skin treatment device according to any one of claims 1 to 15,
The bioadhesive layer is provided to correspond to the shape of the conductive pattern in a planar view.
The skin treatment device according to any one of claims 1 to 16,
A skin treatment device, wherein the resistance value of the conductive pattern and the bioadhesive layer as a whole, or the conductive pattern alone, when not stretched is 1000 Ω or less.
The skin treatment device according to any one of claims 1 to 17,
The conductive sheet further includes a masking portion provided so as to cover a portion of the sheet base material,
The masking portion has at least one of a function of blocking the current supplied to the skin surface of the user and a function of reducing the elasticity of the conductive sheet.
A conductive sheet used to supply an electric current to a user's skin surface, at least a part of which is stretchable in any direction, or at least a part of which is flexible enough to conform to the skin surface,
The sheet has a sheet substrate, a conductive pattern, and a bioadhesive layer,
the conductive pattern is provided on one surface of the sheet base material and includes a wiring portion and an electrode portion connected to one end of the wiring portion;
The conductive sheet, wherein the bioadhesive layer is provided on the opposite side of the conductive pattern to the sheet substrate and is configured to be attached to the skin surface of the user.
20. The conductive sheet according to claim 19,
The conductive sheet, wherein the bioadhesive layer is in a gel state.