KR101874550B1

KR101874550B1 - Heating plate and manufacturing method thereof

Info

Publication number: KR101874550B1
Application number: KR1020170012218A
Authority: KR
Inventors: 정재필; 노명환; 정도현
Original assignee: 서울시립대학교 산학협력단
Priority date: 2017-01-25
Filing date: 2017-01-25
Publication date: 2018-07-04

Abstract

A surface heating element includes a conductive wire formed of an irregular network structure and an uneven part formed on the surface of the conductive wire by metal sputtering to increase the surface area of the conductive wire.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a planar heating element and a planar heating element,

The present invention relates to a planar heating element and a method of manufacturing the planar heating element.

A surface heating element is an object that generates heat in a plane state. A metal electrode is placed on both sides of a conductive heating element on a thin surface, and is insulated with an insulating material to apply a rated voltage to the metal electrode. . Silver (Ag), copper (Cu) or the like is used as the electrode material of the planar heating element, and carbon paste, carbon fiber or the like is used as the material of the heating element made of carbon.

The surface heating element has an advantage of being excellent in heat generation efficiency compared with the conventional linear heating element, capable of rapid heating control, and having a small volume occupied by the heat generation structure, so that it can be applied to various products. These advantages of the surface heating element are that it is possible to use a transparent / flexible heater used in an automobile glass, a house interior / exterior, etc., a flexible / stretchable / wearable heat treatment device utilizing a high thermal efficiency, (wearable) heating device or the like.

Regarding such surface heating elements, Korean Patent Registration No. 10-1028843 discloses a carbon fiber surface heating element and a manufacturing method thereof.

The conventional carbon surface heating element has a danger of fire and deterioration of the heating efficiency due to the continuous heat generation and the damage of the heating structure due to the external force, so that a planar heating element using conductive fiber has been suggested as an alternative. The conductive fiber-based planar heating elements use Ag, Cu, CNT or the like for electrical conductivity and chemical stability, but these materials have disadvantages in that the cost of the planar heating element based on the conductive fiber is increased due to the high unit cost . When an inexpensive material is used to improve this, there is a problem that the electrical conductivity is low or the chemical stability is poor. Accordingly, there is a demand for a planar heating element having electrical conductivity and chemical stability while using an inexpensive material.

And a method of manufacturing a planar heating element and a planar heating element which increase the surface area of the conductive wire by forming irregularities on the surface of the conductive wire by metal sputtering. There is provided a method of manufacturing a planar heating element and a planar heating element which provide conductive nanoparticles between adjacent conductive wires to increase the points of contact of the conductive wires. The present invention provides a method of manufacturing a planar heating element and a planar heating element that provides a heating net structure with improved heating efficiency by dispersing conductive nanoparticles in a heating net structure composed of conductive wires. And a method of manufacturing a planar heating element and a planar heating element using conductive wires made of aluminum (Al), iron (Fe), and alloys thereof, which correspond to the low-cost metal group. There is provided a method of manufacturing a planar heating element and a planar heating element capable of solving the problems of low electrical conductivity and heating structure damage which can be generated by using a low cost metal group for the conductive wire to lower the manufacturing cost of the planar heating element by plating the conductive wire I want to. It is to be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

As a technical means for achieving the above technical object, an embodiment of the present invention includes a conductive wire formed of an irregular network structure and a concavo-convex portion formed on the surface of the conductive wire by metal sputtering to increase the surface area of the conductive wire Can be provided.

According to one example, the diameter of the concave-convex portion may be 10 nm to 1 탆. The concavities and convexities may be formed by performing the metal sputtering for 3 seconds to 120 seconds.

According to one example, the conductive wire may be a metal nanowire. The aspect ratio of the metal nanowires may be 300 or more. The diameter of the metal nanowires may be between 5 and 500 nm.

According to one example, the metal sputtering is a metal sputtering which is performed with a target metal of one of Ag, Au, Cu, Co, Ti, Cr, Mn, Fe, Ni, Zn, W, Al, Lt; / RTI >

According to one example, the planar heating element may further include conductive nanoparticles provided between adjacent conductive wires to increase a point of contact of the conductive wire. The particle diameter of the conductive nanoparticles may be 3 times or less the diameter of the conductive wire. The conductive wire may be provided on the surface of the conductive wire with a metal plating film having higher electrical conductivity than the material constituting the conductive wire.

According to another embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a concave-convex portion for increasing a surface area on a surface of a conductive wire by metal sputtering; dispersing the conductive wire having the concavo- The method comprising the steps of:

According to one example, the metal sputtering may be performed for 3 seconds to 120 seconds. The metal sputtering may be metal sputtering in which one or both of Sn, Au, Cu, Co, Ti, Cr, Mn, Fe, Ni, Zn, W, Al and Sn is used as a target metal. The metal sputtering may be performed in a vacuum atmosphere of 10 < ^-3 > torr or less while maintaining the distance between the conductive wire and the target metal at 4 to 6 cm.

According to one example, the conductive wire may be a metal nanowire. After the step of dispersing the conductive wire, the method may further include dispersing the conductive nanoparticles in the coating solution in which the conductive wire is dispersed to increase the point of contact of the conductive wire. The step of dispersing the conductive wire may include the step of dispersing the conductive wire in the coating solution in an amount of 0.1 to 5 wt%, wherein the step of dispersing the conductive nanoparticles includes dispersing the conductive wire in a coating solution in which the conductive wire is dispersed, And 20 wt% or less of the conductive nanoparticles.

According to one example, after the step of forming the concave-convex portion and before the step of dispersing the conductive wire, the step of plating the surface of the conductive wire with a metal having higher corrosion resistance than the conductive wire may be further included. The plating step may be performed by a method selected from PVD, displacement plating and reduction plating.

According to an exemplary embodiment of the present invention, after forming the irregular network structure of the conductive wire, an electrode is formed at both ends of the network structure, and the packaging structure is formed by performing heat treatment on the network structure and the substrate on which the electrode is formed can do.

The above-described task solution is merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, there may be additional embodiments described in the drawings and the detailed description of the invention.

According to any one of the above-mentioned objects of the present invention, there can be provided a method of manufacturing a planar heating element and a planar heating element that increases the surface area of a conductive wire by forming irregularities on the surface of the conductive wire using metal sputtering. A method of manufacturing a planar heating element and a planar heating element that provide conductive nanoparticles between adjacent conductive wires to increase the points of contact of the conductive wires can be provided. It is possible to provide a planar heating element and a planar heating element which provide a heating net structure with improved heating efficiency by dispersing conductive nano particles in a heating net structure composed of conductive wires. Also, it is possible to provide a method of manufacturing a planar heating element and a planar heating element using a conductive wire made of aluminum (Al), iron (Fe), or an alloy thereof corresponding to a low-cost metal group. In addition, a method of manufacturing a planar heating element and a planar heating element capable of solving the problems of low electrical conductivity and heat generation damage caused by the use of a low-cost metal group in a conductive wire to lower manufacturing cost of the planar heating element by plating the conductive nano structure Can be provided.

1 is a view showing a planar heating element according to an embodiment of the present invention.
2 is an exemplary view for explaining a process of performing metal sputtering to form a concave-convex portion on a surface of a conductive wire according to an embodiment of the present invention.
3 is an exemplary view for explaining a process of plating a conductive wire according to an embodiment of the present invention.
FIG. 4A is a view showing a contact point of a conductive wire of the prior art, and FIG. 4B is a view showing a contact point of a conductive wire whose surface area is increased by metal sputtering according to an embodiment of the present invention.
5 is a view illustrating a planar heating element having an irregular net structure according to an embodiment of the present invention.
6 is a view for explaining a process of packaging a planar heating element according to an embodiment of the present invention.
FIG. 7A is a view showing a conventional conductive wire, and FIG. 7B is a view illustrating a conductive wire formed by metal sputtering according to an embodiment of the present invention.
8 is a view illustrating a transparent surface heating element manufactured using a conductive wire having a concavo-convex portion formed by metal sputtering according to an embodiment of the present invention.
9 is a flowchart of a method of manufacturing the planar heating element according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a planar heating element according to an embodiment of the present invention. 1, the planar heating element may include a conductive wire 110, a substrate 120, an electrode 130, a packaging material 140, and a wire (not shown).

The conductive wire 110 may have an aspect ratio of 300 or more and a diameter of 5 to 500 nm. For example, the conductive wire 110 may be formed of a metal such as Fe, Ag, Au, Cu, Al, Co, Ti, A metal selected from chromium (Cr), manganese (Mn), nickel (Ni), zinc (Zn), tungsten (W) and tin (Sn) or an alloy thereof. Alternatively, the conductive wire 110 may be formed of a single-wall carbon nanotube (SW-CNT), a multi-wall carbon nanotube (MT-CNT), a graphene, or the like.

The process of manufacturing the planar heating element using the conductive wire 110 will be described in detail with reference to FIGS. 2 to 6. FIG.

2 is an exemplary view for explaining a process of performing metal sputtering to form a concave-convex portion on a surface of a conductive wire according to an embodiment of the present invention. Referring to FIG. 2, the conductive wire 200 may be formed with irregularities on the surface of the conductive wire 200 by metal sputtering to increase the surface area. The diameter of the irregular portion may be 10 nm to 1 占 퐉, and may be formed by performing metal sputtering for 3 seconds to 120 seconds. The metal that can be used for the metal sputtering 210 includes, for example, one or a combination of two or more of Ag, Au, Cu, Co, Ti, Cr, Mn, Fe, Ni, Zn, .

For example, the surface of the conductive wire 200 may be formed by metal sputtering (210) of physical vapor deposition (PVD). The metal sputtering 210 is performed for 3 seconds to 120 seconds, and may be Ni sputtering performed, for example, using Ni as the target metal 211. At this time, the conductive wire 200 may be plated on the surface 212 of the conductive wire 200 facing the target 211, and may be formed by physical vapor deposition (PVD) to increase the contact point between the conductive wires 200. [ The concave and convex portions may be formed on the surface of the conductive wire 200. The Ni sputtering may be carried out, for example, in a vacuum atmosphere of 10 ^-3 torr or less while maintaining the distance between the conductive wire 200 and Ni as the target metal at 4 to 6 seconds.

3 is an exemplary view for explaining a process of plating a conductive wire according to an embodiment of the present invention. Referring to FIG. 3, the conductive wire 300 may be formed by forming a conductive wire 300 on the surface of the conductive wire 300 to improve corrosion resistance and chemical stability after the irregularities are formed and before the conductive wire 300 is dispersed. The metal 310 having a higher corrosion resistance than the metal 310 can be plated. For example, the plating treatment may be performed by a method selected from physical vapor deposition (PVD), displacement plating and reduction plating to uniform the surface of the conductive wire 300. [ Accordingly, the conductive wire 300 can be provided on the surface of the conductive wire 300 with a metal plating film having a higher corrosion resistance than the material constituting the conductive wire 300.

For example, the surface of conductive wire 300 may be plated through displacement plating 320. For example, when the conductive wire 300 is immersed in a plating solution in which ions of a metal 310 having a lower ionization tendency than a metal plating material are melted, M ₁ + M ₂ ⁺ M ₁ ⁺ + M ₂ reactions (M ₁ : plated material, M ₂ : plated material) can be advanced. By using the displacement plating (320) method, the immersed plating material can be plated over the entire surface, and a plated surface thinner and more flat than the reduction plating can be obtained due to the characteristics of the plating to be substituted with the metal on the surface of the material to be plated. (Au), tin (Sn), or the like, which is higher in corrosion resistance or chemical stability than the metal (310) or iron (Fe) , Nickel (Ni), lead (Pb) or the like can be used.

As another example, the surface of the conductive wire 300 may be plated through the reduction plating 330. For example, the conductive wire 300 can be plated by immersing the plating material in the plating solution in which the plating metal 310 ions are present, and the M ⁺ + e ^- M reaction can be performed using a reducing agent . The reduction plating (330) method can plastically deposit the plating material immersed in the solution in all directions, and simultaneously obtain corrosion resistance and chemical stability. The plating material is preferably a metal having superior corrosion resistance than iron (Fe), or a metal having superior chemical stability than iron (Fe), such as silver (Ag), gold (Au), zinc (Zn), tin (Ni) or the like may be used.

As the displacement plating 320 and the reduction plating 330 method are performed in an aqueous solution, a process of filtering the plated conductive wire 300 is required. For example, a filtration method using a filter paper and a centrifugation method may be used to separate the conductive wire 300 from an aqueous solution.

When the plating of the conductive wire 300 is completed, the conductive wire 300 having the concave-convex portion in the coating solution can be dispersed. For example, 0.1 to 5 wt% of the conductive wire may be dispersed in a coating solution such as methanol, ethanol, distilled water, IPA, and the like. The coating solution is highly volatile at room temperature, and when the coating solution in which the conductive wire is dispersed is applied to the substrate 130, the coating solution may evaporate within a short period of time to allow the adsorption of the remaining conductive wire.

In this case, when aggregation occurs in the conductive wire, a method using a dispersant, a method using an ultrasonic wave, a method using a stirrer, or the like may be used to suppress aggregation. The method using a dispersant may use 0.5 wt% or less of a surfactant (anion, cation, nonionic surfactant), and the dispersant may include, for example, poly ethylene glycol, octyl phenoxy polyethoxy ethanol, sodium, dodecylsulfate, have. In the method using ultrasonic waves, the aggregation of the conductive wires can be dispersed by applying an ultrasonic wave in the range of 0 to 20 kHz for 1 hour or more. The method using a stirrer can disperse the agglomeration by performing stirring at a speed of 1000 rpm or more.

The conductive nanoparticles can be dispersed in the coating solution in which the conductive wire is dispersed to increase the point of contact of the conductive wire. The conductive nanoparticles may be, for example, copper (Cu) nanoparticles, nickel (Ni) nanoparticles, or cobalt (Co) nanoparticles. Alternatively, the conductive nanoparticles may be graphene, MW-CNT, SW-CNT, or the like. The diameter of the conductive nanoparticles 120 may be three times or less the diameter of the conductive wire 110. For example, conductive nanoparticles of 20 wt% or less of the weight of the conductive wire can be dispersed in the coating solution in which the conductive wire is dispersed. The amount of the conductive nanoparticles to be added may be, for example, 0.5 g or less per 100 g of the dispersion.

FIG. 4A is a view showing a contact point of a conductive wire of the prior art, and FIG. 4B is a view showing a contact point of a conductive wire whose surface area is increased by metal sputtering according to an embodiment of the present invention.

4A is a view showing the contact point 420 of the conductive wire 410 of the prior art. Referring to FIG. 4A, the conductive wire 410 may provide a point of contact resistance generation at a limited contact point 420 of the conductive wire 410 when a current is applied, thereby providing a planar heating element having exothermicity.

4B is a view showing a contact point 450 of the conductive wire 430 including the concave-convex portion 440 according to an embodiment of the present invention. Referring to FIG. 4B, the irregularities 440 may be formed on the surface of the conductive wire 430 by metal sputtering to increase the surface area of the conductive wire 430. The number of contact points of the conductive wire 430 can be increased by the protrusions 440 formed on the surface of the conductive wire 430.

As described above, the conductive wire 430 of FIG. 4B has an advantage that the contact point 450 increases, and when the same current is applied, an improved calorific value can be obtained even if a less amount of material is used than in FIG. 4A.

5 is a view illustrating a planar heating element having an irregular net structure according to an embodiment of the present invention. Referring to FIGS. 1 and 5, an irregular network structure 500 of the conductive wire 110 can be formed by dispersing the conductive wire 110 formed in the coating solution on the substrate 120. At this time, the conductive nanoparticles 510 may be dispersed in the coating solution in which the conductive wires 110 are dispersed to increase the point of contact of the conductive wires 110. The substrate 120 may be made of a polymer such as PET, PVCD or PDMS, or a flexible substrate made of fiber, paper or the like may be used. Alternatively, the substrate 120 may be a hard substrate selected from ceramic, glass, and printed circuit boards (PCB).

Dip coating, spray coating, spin coating, drop coating, or the like is used to form an irregular network structure 500 on the substrate 120 using a coating solution. Can be used. At this time, when the coating solution is overlaid on the substrate, the density of the irregular network structure 500 formed by using air brushing, brushing, spin coating or the like can be adjusted.

6 is a view for explaining a process of packaging a planar heating element according to an embodiment of the present invention. Referring to FIGS. 1 and 6, the electrodes 130 may be formed on both ends of the substrate 120 on which the irregular network structure 600 is formed. As the electrode forming method, a metal paste, a metal foil, a metal PVD, or the like can be used. The metal used for forming the electrode is platinum (Pt), gold (Au), silver (Ag), copper (Cu) Al), and the like.

The net structure and the substrate on which the electrode is formed can be subjected to heat treatment to perform packaging. This is because, by packaging the exposed irregular network structure, the surface property of the surface heating element can be imparted to the surface, and the network structure can be shielded from the external environment. Further, in the case of a wearable surface heating element, the portion in which the current flows does not contact the body, and the heat generated in the heating portion directly touches the heating portion, thereby preventing an excessive temperature rise can do.

If the void space between the conductive wires constituting the irregular net structure 600 is molded with the packaging material, the heat generating performance can be prevented from being lost by the external force such as bending, folding, and pulling of the surface heating element.

FIG. 7A is a view showing a conventional conductive wire, and FIG. 7B is a view illustrating a conductive wire formed by metal sputtering according to an embodiment of the present invention.

7A is a view showing a conventional silver nanowire (AgNW). Referring to FIG. 7A, the silver nanowire 700 may have a diameter of 20 to 30 nm, a length of 20 to 30 μm, and an aspect ratio of 300 to 1500.

FIG. 7B is a view showing a silver nanowire (AgNW) formed by metal sputtering according to an embodiment of the present invention. Referring to FIG. 7B, irregularities can be formed by depositing conductive nanoparticles on the surface of the conventional silver nanowire 710 of FIG. 7A by performing Ni sputtering.

For example, the distance between the nanowire 710 of FIG. 7A and nickel (Ni) as a target metal is maintained at 4 to 6 seconds, and Ni sputtering is performed in a vacuum atmosphere of 10 ^-3 torr for 50 seconds to form conductive nanoparticles Lt; / RTI >

As a result of the SEM analysis of the silver nanowires 710 on which the conductive nanoparticles are deposited, particles of 10 nm to 1 μm diameter are deposited on the surface of the silver nanowires 710.

8 is a view illustrating a transparent surface heating element manufactured using a conductive wire having a concavo-convex portion formed by metal sputtering according to an embodiment of the present invention. Referring to FIG. 8, the saturation temperature can be confirmed through a transparent surface heating element manufactured by using a conductive wire having a size of 30 mm x 30 mm x 0.7 mm formed with concave and convex portions by metal sputtering.

The planar heating element can be manufactured by forming a heating structure on a transparent glass substrate. For example, the silver nanowire (AgNW) coating solution formed with irregularities by Ni sputtering was spin coated at 1500 RPM, and ethanol was evaporated. Thereafter, 0.5 mm thick Electrodes can be formed using conductive silver paste. At this time, a PDMS mixed solution having a ratio of resin to hardener of 10: 1 was uniformly coated on the surface of the substrate of the surface heating element using a transparent glass substrate, and the substrate was heat-treated at 150 ° C for 20 minutes using an atmospheric oven Then, when a voltage of 5 V was applied, it can be seen that the saturation temperature reached 53.2 占 폚 (800). However, the saturation temperature may be slightly different depending on the temperature measurement equipment.

9 is a flowchart of a method of manufacturing the planar heating element according to an embodiment of the present invention. The manufacturing method of the planar heating element according to the embodiment shown in FIG. 9 includes the steps of manufacturing the planar heating element according to the embodiment shown in FIGS. 1 to 8 in a time-series manner. Therefore, the contents already described with respect to the planar heating element according to the embodiment shown in Figs. 1 to 8 are applied to the planar heating element manufacturing method according to the embodiment shown in Fig.

In the step S910, the method for producing the area heating element of the present invention may include the step of forming irregularities for increasing the surface area on the surface of the conductive wire by using metal sputtering. The conductive wire may be, for example, a metal nanowire. Sputtering a metal, for example, the sputtering is performed with Ni and Ni is performed 3 seconds to 120 seconds to the target metal, Ni is sputtered at a distance between the target metal of the conductive wire 4 Ni ~ 6 seconds and 10 ^-3 torr Or less in a vacuum atmosphere.

In the step S920, the method for producing a planar heating element of the present invention may include dispersing a conductive wire having a concavo-convex portion in a coating solution. For example, 0.1 to 5 wt% of the conductive wire may be dispersed in the coating solution. The step of dispersing the conductive nanoparticles may further comprise dispersing the conductive nanoparticles in a coating solution in which the conductive wires are dispersed to increase the point of contact of the conductive wires after the step of dispersing the conductive wires, It is possible to disperse not more than 20 wt% of the conductive nanoparticles by weight of the conductive wire in the dispersed coating solution.

In the step S930, the method for manufacturing the area heating element of the present invention may include forming the irregular network structure of the conductive wire.

Although not shown in Fig. 9, the method for manufacturing the planar heating element of the present invention includes a step of plating the surface of the conductive wire with a metal having a higher electroconductivity than the conductive wire after the step of forming the uneven portion and before the step of dispersing the conductive wire As shown in FIG. At this time, the plating treatment may be performed by a method selected from PVD, displacement plating and reduction plating.

Although not shown in FIG. 9, in the method of manufacturing a planar heating element of the present invention, after forming the irregular network structure of the conductive wire, electrodes are formed at both ends of the network structure, And performing the packaging.

In the above description, steps S910 to S930 may be further divided into further steps or combined into fewer steps, according to an embodiment of the present invention. Also, some of the steps may be omitted as necessary, and the order between the steps may be changed.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

110: conductive wire
120: substrate
130: Electrode
140: Packaging material

Claims

In the planar heating element,
A conductive wire formed of an irregular network structure; And
The conductive wire may be formed by a metal sputtering process to increase the surface area of the conductive wire,
.

The method according to claim 1,
And the diameter of the concave-convex portion is 10 nm to 1 占 퐉.

3. The method according to claim 1 or 2,
Wherein the convexo-concave portion is formed by performing the metal sputtering for 3 seconds to 120 seconds.

3. The method according to claim 1 or 2,
Wherein the conductive wire is a metal nanowire.

5. The method of claim 4,
Wherein the aspect ratio of the metal nanowires is 300 or more.

5. The method of claim 4,
Wherein the metal nanowires have a diameter of 5 to 500 nm.

3. The method according to claim 1 or 2,
The metal sputtering is metal sputtering which is performed using one of or a mixture of two or more of Ag, Au, Cu, Co, Ti, Cr, Mn, Fe, Ni, Zn, W, .

3. The method according to claim 1 or 2,
Wherein the planar heating element further comprises conductive nanoparticles provided between adjacent conductive wires to increase a point of contact of the conductive wire.

9. The method of claim 8,
Wherein a particle diameter of the conductive nanoparticles is 3 times or less the diameter of the conductive wire.

3. The method according to claim 1 or 2,
Wherein the conductive wire comprises a metal plating film having a higher electrical conductivity than the material constituting the conductive wire on the surface of the conductive wire.

A method for producing an area heating element,
Forming a concavity and convexity on the surface of the conductive wire to increase the surface area using metal sputtering;
Dispersing the conductive wire in which the concave-convex part is formed in a coating solution; And
Forming an irregular network structure of the conductive wire;
And heating the surface heating element.

12. The method of claim 11,
Wherein the metal sputtering is performed for 3 seconds to 120 seconds.

13. The method according to claim 11 or 12,
The metal sputtering is metal sputtering which is performed using one of or a mixture of two or more of Ag, Au, Cu, Co, Ti, Cr, Mn, Fe, Ni, Zn, W, Of the surface heating element.

14. The method of claim 13,
Wherein the metal sputtering is performed in a vacuum atmosphere of 10 < ^-3 > torr or less while maintaining the distance between the conductive wire and the target metal at 4 to 6 cm.

13. The method according to claim 11 or 12,
Wherein the conductive wire is a metal nanowire.

13. The method according to claim 11 or 12,
Further comprising the step of dispersing the conductive nanoparticles in the coating solution in which the conductive wire is dispersed to increase the point of contact of the conductive wire after the step of dispersing the conductive wire.

delete

13. The method according to claim 11 or 12,
Further comprising a step of plating the surface of the conductive wire with a metal having a higher corrosion resistance than the conductive wire after the step of forming the concave-convex portion and before the step of dispersing the conductive wire. Way.

19. The method of claim 18,
Wherein the plating step is performed by a method selected from PVD, substitution plating and reduction plating.

13. The method according to claim 11 or 12,
Forming an irregular network structure of the conductive wire, forming an electrode at both ends of the network structure, and performing heat treatment on the network structure and the substrate on which the electrode is formed to perform packaging. Of the surface heating element.