KR102062616B1 - Film for preventing counterfeit and method for regulating infrared emissivity - Google Patents

Abstract

The present invention relates to an anti-counterfeiting film and an infrared radiation control method, and more particularly, a substrate, a graphene pattern disposed on at least a portion of one surface of the substrate and at least a portion of the surface of the substrate, covering the graphene pattern. It includes a metal film, the metal film has a thickness less than the minimum thickness of the inherent infrared radiation of the metal, it is possible to check the infrared radiation pattern according to the graphene pattern when measuring the infrared radiation has excellent anti-counterfeiting effect It relates to an anti-counterfeiting film and infrared radiation control method that can be represented.

Description

FILM FOR PREVENTING COUNTERFEIT AND METHOD FOR REGULATING INFRARED EMISSIVITY}

The present invention relates to an anti-counterfeiting film and an infrared radiation control method.

Recently, as forgery and tampering of branded products has emerged as a social problem, various technologies for preventing forgery and tampering have been developed. For example, holograms attached to the product in the form of anti-counterfeiting stickers, RFID in the form of electronic tags, optically variable ink (OVI), braille, intaglio printing, etc., which are implemented through printing methods. Can be mentioned.

The most representative technique is a hologram, and a hologram is a medium recording interference fringes that reproduce a three-dimensional image, and is made using the principle of holography. However, the information that can be recorded by such a hologram has a limit, it is difficult to produce a sophisticated hologram, and there has been a problem that it is difficult for consumers to actually determine the authenticity.

In addition, RFID, which stores unique ID or data read from the sensor, and transmits the information in various ways when the reader requests it, is bulky and expensive, so it is expensive to apply to the product, and to determine authenticity. A separate reader is required and not easy for consumers to use.

In addition, OVI, which shows different colors according to the viewing angle, is widely applied to security prints such as banknotes, but it is difficult for ordinary people such as consumers to recognize the change in color, and there is a limitation in the applied product. There is.

Accordingly, there is still a need for anti-counterfeiting technology to allow the general consumer to easily determine the authenticity of the product while being able to attach to various products requiring anti-counterfeiting at low cost.

Korean Registered Patent No. 1173374

An object of the present invention is to provide an anti-counterfeiting film that can be identified by simply identifying a specific pattern by measuring the infrared, heat, and the like.

An object of the present invention is to provide a method for adjusting infrared radiation.

1. description,

Graphene patterns disposed on at least a portion of one side of the substrate and

A metal film disposed on at least a portion of one surface of the substrate and covering the graphene pattern;

The metal film is an anti-counterfeiting film having a thickness less than the minimum thickness of the infrared radiation of the metal is measured.

2. In the above 1, wherein the graphene is at least one of graphene, graphene oxide and reduced graphene oxide, anti-counterfeiting film.

3. In the above 1, wherein the thickness of the graphene pattern is 0.1nm to 1nm, anti-counterfeiting film.

4. In the above 1, the metal is copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), cobalt (Co), ruthenium (Ru), palladium (Pd) , Chromium (Cr), manganese (Mn), gold (Au), silver (Ag), molybdenum (Mo), rhodium (Rh), tantalum (Ta), titanium (Ti), tungsten (W), uranium (U) , Vanadium (V), zirconium (Zr), iridium (Ir), brass (brass), bronze (bronze), stainless steel (stainless steel) and at least one selected from the group consisting of alloys, anti-counterfeiting film.

5. In the above 1, wherein the thickness of the metal film is 1nm to 100nm, anti-counterfeiting film.

6. In the above 1, wherein the metal film has a different infrared radiation according to the presence of the graphene pattern of the lower side anti-counterfeiting film.

7. forming a graphene pattern on at least a portion of one surface of the substrate, and

Forming a metal film covering the graphene pattern on the substrate;

And the metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured.

8. In the above 7, wherein the graphene is at least one of graphene, graphene oxide and reduced graphene oxide, infrared radiation control method.

9. In the above 7, the thickness of the graphene pattern is 0.1nm to 1nm, infrared radiation control method.

10. In the above 7, the metal is copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), cobalt (Co), ruthenium (Ru), palladium (Pd) , Chromium (Cr), manganese (Mn), gold (Au), silver (Ag), molybdenum (Mo), rhodium (Rh), tantalum (Ta), titanium (Ti), tungsten (W), uranium (U) At least one selected from the group consisting of vanadium (V), zirconium (Zr), iridium (Ir), brass, bronze, stainless steel and alloys thereof. .

11. In the above 7, the thickness of the metal film is 1 nm to 100 nm, infrared radiation control method.

Anti-counterfeiting film of the present invention has a different infrared radiation according to the presence of the graphene pattern on the back of the metal film, by measuring the infrared radiation, heat, it is possible to check the pattern according to the specific pattern of the graphene pattern. Thus, it can be applied as an anti-counterfeiting film can exhibit excellent anti-counterfeiting efficacy.

1 is a comparison result between a metal film Au alone and a laminate in which a graphene pattern is formed on the metal film. a is the difference in infrared radiation and b is the charge density difference.
2 is a comparison result between a metal film Ag alone and a laminate in which a graphene pattern is formed on the metal film. a is the difference in infrared radiation and b is the charge density difference.
3 is a comparison result between a metal film Al alone and a laminate in which a graphene pattern is formed on the metal film. a is the difference in infrared radiation and b is the charge density difference.
3 is an IR image (a) and a thermal mapping image (b) of a laminate in which a graphene pattern is formed on the metal film Au.
4 is an IR image (a) and a thermal mapping image (b) of a laminate in which a graphene pattern is formed on the metal film Ag.
5 is an IR image (a) and a thermal mapping image (b) of a laminate in which a graphene pattern is formed on the metal film Al.
Figure 6 is a general digital camera image and infrared camera image of the anti-counterfeiting film according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The anti-counterfeiting film of the present invention includes a substrate, a graphene pattern and a metal film.

The present invention is based on the finding that due to the optical specificity between the graphene and the nano metal film, the infrared radiation of the metal film differs depending on the presence of the lower graphene pattern.

As the substrate supports the graphene pattern and the metal film, any material capable of supporting them may be used without limitation, and any material known in the art may be used without limitation. For example, organic materials, such as Si, Ge wafer, glass, or plastics with flexibility, can be used.

Available organics include, for example, polyimide (PI), polycarbonate (PC), polyethersulfone (PES), polyetheretherketone (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), poly Vinyl chloride (PVC), polyethylene (PE), ethylene copolymer, polypropylene (PP), propylene copolymer, poly (4-methyl-1-pentene) (TPX), polyarylate (PAR), polyacetal (POM ), Polyphenylene oxide (PPO), polysulfone (PSF), polyphenylene sulfide (PPS), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAC), polyvinyl alcohol (PVAL), polyvinyl acetal, Polystyrene (PS), AS resin, ABS resin, polymethyl methacrylate (PMMA), fluorocarbon resin, phenolic resin (PF), melamine resin (MF), urea resin (UF), unsaturated polyester (UP), epoxy resin (EP), diallyl phthalate resin (DAP), polyurethane (PUR), polyamide (PA), silicone resin (SI) or mixtures and compounds thereof. Available.

The thickness of the substrate is not particularly limited, and may be, for example, 0.1 μm to 1000 μm.

If necessary, the substrate may be one having at least one functional group of a hydroxy group, a thiol group, and a perfluoroalkyl group. In such a case, since the metal atoms of the metal film on the graphene layer interact with the functional group, uniform metal nucleation and crystal growth are possible, so that even if manufactured with several thin ultrathin layers, a continuous thin film can be formed without grain-boundaries. It is possible to provide a conductive metal ultra-thin film that could not be achieved by the prior art.

For example, the solid substrate having the hydroxy group may be prepared by thermally oxidizing the silica substrate or by treating with an oxygen plasma, but is not limited thereto.

Further, the solid substrate having the thiol group and the perfluoroalkyl group may be prepared by treating the solid substrate having the hydroxy group with a mercaptoalkylalkoxysilane and a perfluoroalkylalkoxysilane, respectively, but is not limited thereto. For example, (3-mercaptopropyl) trimethoxysilane (MPTMS) is used as the mercaptoalkylalkoxysilane, and FAS-13 (1H, 1H, 2H) is used as perfluoroalkylalkoxysilane. , 2H-perfluorooctyltriethoxysilane) may be used, but is not limited thereto.

The graphene pattern is disposed on at least a portion of one surface of the substrate.

Since the graphene pattern is disposed on at least a portion of one surface of the substrate, there is a difference in infrared radiation between a portion having graphene and a portion not having a lower portion of the metal film, and the difference may appear in the form of a graphene pattern. Thus, it can be used as a forgery prevention pattern. The infrared radiation difference is determined by exchanging electrons with graphene according to the work function of the metal.

The at least part is not particularly limited as long as the difference in infrared radiation degree can be recognized, and may be any area except the entirety of one surface of the substrate, and may have a pattern of a specific figure, a character, or the like.

The graphene of the graphene pattern may be graphene, graphene oxide, reduced graphene oxide or at least one of them.

The thickness of the graphene pattern is not particularly limited, and may be, for example, 0.1 nm to 1 nm, specifically 0.1 nm to 0.5 nm.

The metal film is disposed on at least a portion of one surface of the substrate and covers the graphene pattern.

Since all metals have a work function, the metals used in the metal film are not particularly limited and include, for example, copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), Cobalt (Co), Ruthenium (Ru), Palladium (Pd), Chromium (Cr), Manganese (Mn), Gold (Au), Silver (Ag), Molybdenum (Mo), Rhodium (Rh), Tantalum (Ta) , Group consisting of titanium (Ti), tungsten (W), uranium (U), vanadium (V), zirconium (Zr), iridium (Ir), brass, bronze and bronze steel One or more selected from may be mentioned, Preferably, gold, silver, aluminum and the like can be used.

The metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured.

In the present specification, the inherent infrared radiation of the metal refers to the infrared radiation of the metal itself, and when the metal film is formed to a sufficient thickness so that no other material is exposed to the lower side of the metal when the infrared radiation is measured, only the metal film Infrared radiation is measured, and the infrared radiation at that time is an infrared radiation inherent in the metal.

When the metal film is formed on the substrate by a method such as vapor deposition, and the metal film exceeds a predetermined thickness and completely covers the substrate at the infrared radiation measurement site, the infrared radiation inherent in the metal is measured. However, if the thickness of the metal film is not sufficient to completely cover the substrate, the metal and the substrate material exposed at the bottom of the infrared radiation measurement part coexist and the infrared radiation value is changed.

The minimum thickness at which the inherent infrared radiation is measured means the minimum thickness that completely covers the substrate.

In the present invention, the metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured, so that a value other than the inherent infrared radiation is measured.

For example, after forming a film of the same metal as the metal film on the SiO 2 substrate, a value other than the inherent infrared radiation can be measured when measuring the infrared radiation from the metal film side.

That is, in the anti-counterfeiting film of the present invention, the metal film covers the graphene pattern. Since the metal film has the same thickness as above, the metal film has a value different from the inherent infrared radiation when measuring the infrared radiation from the metal film side. As described above, the infrared graph also shows a difference in the infrared radiation.

The infrared radiation difference due to the graphene pattern may not appear when the metal film has a thickness greater than the above thickness. For example, in the metal film thickness of 20 nm in Figs. 1 to 3, the infrared radiation degree in the case of forming only the metal film and the graphene pattern and the metal film are almost the same (the infrared radiation degree in the thickness of 20 nm or more is intrinsic to the metal). Emissivity) In this case, when the infrared radiation is measured on the metal film, the thickness of the infrared radiation of the metal film may be 20 nm. The thickness may vary depending on the formation conditions, methods, etc. of the metal film, and may be, for example, within 100 nm, and may be 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, or the like within the range.

The lower limit of the thickness of the metal film is not particularly limited, and for example, the infrared radiation measured at the metal film side in the anti-counterfeiting film may be greater than the thickness of the same as the infrared radiation of the graphene pattern. The thickness may be, for example, 0.1 nm or more, 1 nm or more, 3 nm or more, but is not limited thereto.

In addition, the present invention provides a method for adjusting infrared radiation.

The infrared radiation control method of the present invention includes forming a graphene pattern on at least a portion of one surface of the substrate, and forming a metal film covering the graphene pattern on the substrate.

As the substrate supports the graphene pattern and the metal film, any material capable of supporting them may be used without limitation, and any material known in the art may be used without limitation. For example, organic materials, such as Si, Ge wafer, glass, or plastics with flexibility, can be used.

Available organics include, for example, polyimide (PI), polycarbonate (PC), polyethersulfone (PES), polyetheretherketone (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), poly Vinyl chloride (PVC), polyethylene (PE), ethylene copolymer, polypropylene (PP), propylene copolymer, poly (4-methyl-1-pentene) (TPX), polyarylate (PAR), polyacetal (POM ), Polyphenylene oxide (PPO), polysulfone (PSF), polyphenylene sulfide (PPS), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAC), polyvinyl alcohol (PVAL), polyvinyl acetal, Polystyrene (PS), AS resin, ABS resin, polymethyl methacrylate (PMMA), fluorocarbon resin, phenolic resin (PF), melamine resin (MF), urea resin (UF), unsaturated polyester (UP), epoxy resin (EP), diallyl phthalate resin (DAP), polyurethane (PUR), polyamide (PA), silicone resin (SI) or mixtures and compounds thereof. Available.

The thickness of the substrate is not particularly limited, and may be, for example, 0.1 μm to 1000 μm.

If necessary, the substrate has at least one functional group of a hydroxy group, a thiol group, and a perfluoroalkyl group on one side, and the method of the present invention further includes forming the functional group on the substrate before forming the graphene pattern. can do.

The graphene pattern may be formed by growing graphene on a substrate by deposition or the like, or may be formed by transferring graphene onto a substrate.

The graphene of the graphene pattern may be graphene, graphene oxide, reduced graphene oxide or at least one of them, and the method of the present invention forms the graphenes or oxidizes / reduces them after formation of graphenes. You can.

Pattern formation may be, for example, by photolithography, but is not limited thereto.

The thickness of the graphene pattern is not particularly limited, and may be, for example, 0.1 nm to 1 nm, specifically 0.1 nm to 0.5 nm.

Thereafter, a metal film covering the graphene pattern is formed on the substrate.

The metal film may be formed by a vapor deposition method, for example, by physical vapor deposition (PVD), but is not limited thereto.

The metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured.

When the metal film is formed on the substrate by a method such as vapor deposition, and the metal film exceeds a predetermined thickness and completely covers the substrate at the infrared radiation measurement site, the infrared radiation inherent in the metal is measured. However, if the thickness of the metal film is not sufficient to completely cover the substrate, the metal and the substrate material exposed at the bottom of the infrared radiation measurement part coexist and the infrared radiation value is changed.

In the present invention, the metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured, so that a value other than the inherent infrared radiation is measured.

That is, in the anti-counterfeiting film of the present invention, the metal film covers the graphene pattern. Since the metal film has the same thickness as above, the metal film has a value different from the inherent infrared radiation when measuring the infrared radiation from the metal film side. As described above, the infrared graph also shows a difference in the infrared radiation.

The infrared radiation difference due to the graphene pattern may not appear when the metal film has a thickness greater than the above thickness. For example, in FIG. 1 to FIG. 3, the thickness of the metal film is about 20 nm, which is almost the same as the case of forming the graphene pattern and the metal film. The thickness at which the infrared radiation of the metal film is measured may be 20 nm. The thickness may vary depending on the formation conditions, methods, etc. of the metal film, and may be, for example, within 100 nm, and may be 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, or the like within the range.

The lower limit of the thickness of the metal film is not particularly limited, and for example, the infrared radiation measured at the metal film side in the anti-counterfeiting film may be greater than the thickness of the same as the infrared radiation of the graphene pattern. The thickness may be, for example, 0.1 nm or more, 1 nm or more, 3 nm or more, but is not limited thereto.

The metal used for the metal film is not particularly limited, and for example, copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), cobalt (Co), ruthenium (Ru), wave Radium (Pd), Chromium (Cr), Manganese (Mn), Gold (Au), Silver (Ag), Molybdenum (Mo), Rhodium (Rh), Tantalum (Ta), Titanium (Ti), Tungsten (W), At least one selected from the group consisting of uranium (U), vanadium (V), zirconium (Zr), iridium (Ir), brass, brass, bronze, stainless steel and alloys thereof Can be.

The infrared radiation of the metal film depends on the presence of the lower graphene pattern, which includes both increasing and decreasing the infrared radiation.

Increasing or decreasing the infrared radiation may be selected by various combinations of metal types, metal film thicknesses, graphene pattern thicknesses, and the like.

For example, as the metal type, the thickness of the graphene pattern is fixed, and the thickness of the metal film is changed, the infrared radiation of the metal film may be higher or lower than before the graphene pattern is formed.

For example, when the metal constituting the metal film is gold (Au), when the metal film thickness is about 12 nm or less, infrared radiation can be reduced by forming a graphene pattern of 0.3 nm, and more than (over) In thickness, infrared radiation may increase by forming a graphene pattern of 0.3 nm.

As another specific example, when the metal constituting the metal film is silver (Ag), when the metal film thickness is about 7 nm, infrared radiation may increase by forming a graphene pattern of 0.3 nm, and more than (excess) In the thickness of), infrared radiation may be reduced by forming a graphene pattern of 0.3 nm, and the difference may be reduced again as the metal film becomes thicker.

As another specific example, when the metal constituting the metal film is aluminum (Al), when the metal film thickness is about 5 nm, infrared radiation can be greatly increased by forming a graphene pattern of 0.3 nm, and more ( Greater than), the infrared radiation may be reduced by forming a graphene pattern of 0.3 nm, and the difference may be reduced again as the metal film becomes thicker.

Also, depending on the type of metal, the change in infrared radiation may be reversed, and the difference may be large or small.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example . Manufacture of anti-counterfeiting film

One. Graphene  Synthesis of templates

Graphene was prepared by low pressure chemical vapor deposition (CVD) on a 4.5 μm thick copper thin film (Alfa Aesar). Prior to synthesis, the copper thin film was washed by soaking in nickel etchant (Transene, TFB). Specific growth conditions are as follows. First, a copper thin film was put into a reactor, and the pressure was reduced, and then heated to 1000 ° C., and annealed for 20 minutes under 100 sccm H ₂ conditions. 30 sccm CH ₄ and 30 sccm H ₂ were introduced for 40 minutes to promote graphene growth. The furnace was cooled to room temperature. The graphene pattern was formed in a lattice pattern with a thickness of 0.3 nm.

2. Graphene  Warrior

The PMMA polymer support layer was formed on the graphene thin film formed from the copper thin film, and the copper thin film was removed by placing it in a copper caustic (CE-100) solution for at least 1 hour. Thereafter, the PMMA / graphene layer was transferred to the SiO ₂ substrate, the solvent was sufficiently dried, and then the PMMA layer was removed with acetone.

3. Graphene  Formation of patterns

In order to form a single layer graphene pattern transferred to SiO ₂ , only the graphene region to be removed is exposed to oxygen plasma or UV / O for at least 30 minutes and blown away. At this time, the area to be left was used a stencil mask or photoresist.

As a pattern, a square pattern and a letter pattern were formed.

The square pattern formed a 100 μm × 100 μm square pattern. At this time, the part shown as a square is a region where graphene does not exist, and a single layer graphene is formed as an area outside the square.

4. Formation of Metallic Crystals

The micro patterned graphene formed on the solid substrate was placed in a thermal evaporator chamber (Edwards AUTO 306) for metal thin film deposition. The chamber was initially depressurized to 2.0 × 10 ⁻⁶ mbar and pure gold pellets (99.999%, iTASCO) were placed in the molybdenum boat (iTASCO) and then evaporated to a current of 55 A. The deposition was carried out at a growth rate of 0.01 dl / s at room temperature (300K) without heating or cooling. The thickness of the thin film was monitored by quartz crystal microbalance (QCM).

Aluminum and silver were carried out in the same manner as above.

Experimental Example

1. Infrared radiation measurement

We measured the metal film alone is formed by the case and the metal film, the infrared radiation of SiO case of forming a _two-phase to the graphene pattern / metal film also on the SiO ₂ on the metal film side, and the results are also shown in Figs. 1 to 3 (a) It was.

Referring to this, it can be seen that the infrared radiation of the metal film is changed by the formation of the graphene pattern.

2. Charge Density Calculation

Assuming a metal layer of infinite thickness, a metal free surface that can be influenced by graphene to be laminated thereon with three layers (atomic layers) on the inside from the metal layer is defined, and a single layer graphene (thickness 0.3 nm thick) is defined thereon. ) Was laminated. Thereafter, the charge density of the laminated structure was calculated through the first principle computer simulation, and the results are shown in FIGS. 1 to 3 (b).

Referring to this, it can be seen that the charge density of the metal film is changed by the formation of the graphene pattern.

3. infrared / heat Mapping  Image shooting

In order to obtain the greatest anti-counterfeiting effect according to the presence or absence of graphene, the thickness showing the largest difference in the degree of emissivity among the thickness conditions of each metal was used as the optimum condition. At this time, the used metal film had thicknesses of Au 7 nm, Ag 7 nm, and Al 5 nm.

An infrared image and a heat mapping image of the metal film side of the laminate on which the graphene square pattern was formed were photographed, and the results are shown in FIGS. 4 to 6.

Referring to this, the infrared radiation degree and temperature of the metal film are changed by the formation of the graphene pattern, so that the lattice pattern of the graphene pattern is confirmed.

4. Digital camera and infrared camera shooting

Anti-counterfeiting film with graphene character pattern was taken by digital camera and infrared camera to compare images.

Referring to FIG. 7, although the pattern is not observed in the general digital camera image, the letter according to the graphene pattern may be identified in the infrared camera, and the temperature of the metal film may be higher than that of the non-letter part. .

Claims (11)

materials,
Graphene patterns disposed on at least a portion of one side of the substrate and
A metal film disposed on at least a portion of one surface of the substrate and covering the graphene pattern;
The metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured,
The metal film has a different infrared radiation according to the presence of the lower graphene pattern anti-counterfeiting film.
The anti-counterfeiting film of claim 1, wherein the graphene is at least one of graphene, graphene oxide, and reduced graphene oxide.
The anti-counterfeiting film of claim 1, wherein the graphene pattern has a thickness of 0.1 nm to 1 nm.
The method of claim 1, wherein the metal is copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), cobalt (Co), ruthenium (Ru), palladium (Pd), chromium (Cr), manganese (Mn), gold (Au), silver (Ag), molybdenum (Mo), rhodium (Rh), tantalum (Ta), titanium (Ti), tungsten (W), uranium (U), vanadium (V), zirconium (Zr), iridium (Ir), brass (brass), bronze (bronze), stainless steel (stainless steel) and at least one selected from the group consisting of alloys, anti-counterfeiting film.
The anti-counterfeiting film of claim 1, wherein the metal film has a thickness of 1 nm to 100 nm.
delete Forming a graphene pattern on at least a portion of one surface of the substrate, and
Forming a metal film covering the graphene pattern on the substrate;
And the metal film has a thickness less than the minimum thickness at which the inherent infrared radiation is measured.
The method of claim 7, wherein the graphene is at least one of graphene, graphene oxide and reduced graphene oxide.
The method of claim 7, wherein the graphene pattern has a thickness of 0.1 nm to 1 nm.
The method of claim 7, wherein the metal is copper (Cu), nickel (Ni), iron (Fe), platinum (Pt), aluminum (Al), cobalt (Co), ruthenium (Ru), palladium (Pd), chromium (Cr), manganese (Mn), gold (Au), silver (Ag), molybdenum (Mo), rhodium (Rh), tantalum (Ta), titanium (Ti), tungsten (W), uranium (U), vanadium (V), zirconium (Zr), iridium (Ir), brass (brass), bronze (bronze), stainless steel (stainless steel) and at least one selected from the group consisting of alloys, infrared radiation control method.
The method of claim 7, wherein the metal film has a thickness of 1 nm to 100 nm.

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