Structure having three-dimensional curved surface

Abstract

Provided is a structure having a three-dimensional curved surface, said structure comprising, in the following order, a metal layer, a dielectric, and a metal pattern region on the dielectric surface, wherein the diameter of the minimum bounding sphere for a meta-atom constituting the metal pattern region is 3 μm to 100 mm, inclusive.

Description

Structure with three-dimensional curved surface

[0001] The present invention relates to a structure having a three-dimensional curved surface.

[0002] In recent years, advances in remote control technology for electronic devices and the widespread use of virtual reality (VR) have led to demands for faster, higher-capacity communications. To achieve this, communication using higher-frequency electromagnetic waves is necessary. High-frequency electromagnetic waves are generally less susceptible to diffraction than lower-frequency waves, and are blocked by obstacles. Therefore, there is a demand for electromagnetic wave control elements that can bypass obstacles and deliver electromagnetic waves to their intended destinations. For example, the use of metamaterials (more specifically, artificial materials that have periodic structures smaller than the wavelength of electromagnetic waves and exhibit behaviors toward those waves that are not found in natural materials) to control the direction of electromagnetic waves has been investigated.

[0003] For example, Non-Patent Document 1 discloses a planar metamaterial that is characterized by forming a plate-like dielectric with a thickness of about 50 nm on a gold foil, and creating a gold pattern on the plate-like dielectric using photolithography, and reflecting electromagnetic waves in the range of 333 THz to 400 THz.

[0004] For example, Non-Patent Document 2 discloses a planar metamaterial characterized by forming copper patterns on both sides of a plate-like dielectric material with a thickness of about 0.787 mm using photolithography, and concentrating electromagnetic waves of 35 GHz to 40 GHz.

[0005] Nano Lett. , 2012, 12, 6223 Sci. Rep. ,2021,11,12671

[0006] However, the planar metamaterials described in Non-Patent Documents 1 and 2 have the problem that they cannot be installed in a shape that conforms to a three-dimensional curved housing. Furthermore, planar metamaterials have the problem that the angle of incidence of electromagnetic waves irradiated onto the planar metamaterial from a specific direction is almost constant at any point on the metamaterial. When the angle of incidence is constant, there is a problem that the control direction of the electromagnetic waves is limited. Non-Patent Documents 1 and 2 do not adequately address the above-mentioned problems caused by the planar shape of the structure.

[0007] The present invention aims to solve the above problems and provide a structure with a three-dimensional curved surface that functions as a metamaterial and enables electromagnetic wave control. In this disclosure, a structure functioning as a metamaterial means that it can control the direction of electromagnetic waves in directions that cannot be achieved by ordinary specular reflection or refraction.

[0008] The present disclosure includes the following items. [Item 1] A structure having a three-dimensional curved surface, comprising, in this order, a metal layer, a dielectric, and a metal pattern region on the surface of the dielectric, wherein the diameter of the smallest encompassing sphere of a meta-atom constituting the metal pattern region is 3 μm or more and 100 mm or less. [Item 2] The structure according to Item 1, further comprising a metal compound layer inside the meta-atom. [Item 3] The structure according to Item 1 or 2, wherein the metal constituting the meta-atom includes copper. [Item 4] The structure according to Item 2, wherein the metal constituting the meta-atom and the metal compound layer includes copper. [Item 5] The structure according to any one of Items 1 to 4, further comprising a resin layer on the outside of the metal pattern region. [Item 6] The structure according to any one of Items 1 to 5, wherein the carbon / metal element concentration ratio of the meta-atom is 1.0 or more and 6.0 or less. [Item 7] The structure according to any one of Items 1 to 6, wherein the water absorption coefficient of the dielectric is 0.2 or less. [Item 8] The structure according to any one of Items 1 to 6, wherein the area of ​​the metal pattern region is 0.09 mm ２ More than 20m ２The structure according to any one of Items 1 to 7, wherein the operating frequency is 0.3 GHz or more and 10 THz or less. [Item 9] The structure according to any one of Items 1 to 8, wherein the operating frequency is 0.3 GHz or more and 10 THz or less. [Item 10] An electromagnetic wave transmission / reception system including the structure according to any one of Items 1 to 9 and an electromagnetic wave oscillation antenna.

[0009] According to one aspect of the present invention, a structure having a three-dimensional curved surface that can control electromagnetic waves in any direction can be provided.

[0010] 1 is a diagram illustrating a structure produced in an example; FIG. 2 is a diagram illustrating a cross-sectional structure of a structure produced in an example; FIG. 3 is a diagram showing the results of the reflection direction when electromagnetic waves are incident on a structure produced in an example; FIG. 4 is a top view of a structure produced in Example 2; FIG. 5 is a cross-sectional view of a structure produced in an example; FIG. 6 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz for the structure of Example 2; FIG. 7 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz for the structure of Example 2; FIG. 8 is a diagram explaining the azimuthal angle and polar angle of the reflection direction in xyz coordinates; FIG. 9 is an apparatus layout diagram when a function confirmation test as a metamaterial is performed on the structure produced in an example; FIG. 10 is an evaluation result when a function confirmation test as a metamaterial is performed on the structure of Example 2, showing the angular distribution of reflected wave intensity at a frequency of 300 GHz; FIG. 11 is a top view of a structure produced in Example 3; FIG. 12 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz for the structure of Example 3. 1 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz for the structure of Example 3. FIG. 2 is a diagram showing the angular distribution of reflected wave intensity at a frequency of 300 GHz, which is an evaluation result of a function confirmation test of the structure of Example 3 as a metamaterial. FIG. 3 is a top view of a structure produced in Example 4. FIG. 4 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz for the structure of Example 4. FIG. 5 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz for the structure of Example 4. FIG. 6 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz for the structure of Example 4. FIG. 7 is a diagram showing the evaluation results of a function confirmation test of the structure of Example 4 as a metamaterial, which is an evaluation result of a function confirmation test of the structure of Example 4 as a metamaterial. FIG. 8 is a top view of a structure produced in Example 5. FIG. 9 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz for the structure of Example 5. FIG. 10 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz for the structure of Example 5. 10 is a diagram showing the evaluation results of a function confirmation test as a metamaterial of the structure of Example 5, and is a diagram showing the angular distribution of the reflected wave intensity at a frequency of 300 GHz.10 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz in the structure of Example 6. FIG. 11 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz in the structure of Example 6. FIG. 12 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz in the structure of Example 7. FIG. 13 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz in the structure of Example 7. FIG. 14 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz in the structure of Example 8. FIG. 15 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz in the structure of Example 8. FIG. 16 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the xz plane at a frequency of 300 GHz in the structure of Example 9. FIG. 17 is a diagram showing the calculation results of the angular distribution of reflected wave intensity in the yz plane at a frequency of 300 GHz in the structure of Example 9. FIG. 18 is a top view of a structure produced in Example 10. 10 is a diagram showing the calculation results of the angular distribution of the reflected wave intensity in the xz plane at a frequency of 1.05 THz in the structure of Example 10. FIG. 11 is a diagram showing the calculation results of the angular distribution of the reflected wave intensity in the yz plane at a frequency of 1.05 THz in the structure of Example 10. FIG. 12 is a top view of a structure produced in Example 11. FIG. 13 is a diagram showing the calculation results of the angular distribution of the reflected wave intensity in the xz plane at a frequency of 100 GHz in the structure of Example 11. FIG. 14 is a diagram showing the calculation results of the angular distribution of the reflected wave intensity in the yz plane at a frequency of 100 GHz in the structure of Example 11.

[0011] Illustrative embodiments of the present invention (sometimes referred to as the present embodiments) will be described below, but the present invention is not limited to these embodiments.

[0012] In this disclosure, various measurements are performed based on the methods described in the specification, particularly the methods described in the Examples. In this specification, the upper or lower limit of a stepwise numerical range may be replaced with the upper or lower limit of a corresponding other stepwise numerical range, particularly the corresponding value described in the Examples. Furthermore, in this specification, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the function of the step is achieved. The components (scale, shape, length, etc.) shown in the drawings may be exaggerated for clarity.

[0013] <Structure with a Three-Dimensional Curved Surface> In this embodiment, a three-dimensional curved surface refers to a curved surface that cannot be established by deforming a plane (i.e., it is not a developable surface). The structure of this embodiment is a structure with a three-dimensional curved surface, and includes a metal layer, a dielectric, and a metal pattern region on the dielectric surface. The structure of this embodiment also includes a metal layer, a dielectric, and a metal pattern region on the dielectric surface, in this order.

[0014] [Metal Layer] The metal constituting the metal layer according to this embodiment is not particularly limited, and examples thereof include silver, copper, gold, aluminum, magnesium, zinc, cobalt, nickel, lithium, platinum, palladium, tin, chromium, lead, hafnium, zirconium, bismuth, manganese, titanium, molybdenum, antimony, indium, gallium, calcium, rhodium, iridium, sodium, tungsten, ruthenium, potassium, cadmium, osmium, rubidium, tantalum, strontium, thorium, niobium, protactinium, rhenium, vanadium, barium, arsenic, antimony, lutetium, yttrium, lanthanum, neodymium, thulium, holmium, dysprosium, and germanium. From the viewpoints of ease of processing and improving the transmittance of electromagnetic waves, the metal constituting the metal layer according to this embodiment is preferably silver, copper, gold, platinum, aluminum, nickel, and iron, more preferably silver, copper, gold, platinum, and aluminum, even more preferably silver, copper, and aluminum, and particularly preferably copper. From the same viewpoint as above, copper oxide is preferred as the metal compound.

[0015] From the viewpoint of improving reflectivity, the thickness of the metal layer according to this embodiment is preferably 50 nm or more, or 100 nm or more. From the viewpoint of ease of processing, the thickness of the metal layer according to this embodiment is preferably 200 μm or less, or 100 μm or less. The thickness of the metal layer according to this embodiment is measured by the method described in the Examples.

[0016] [Dielectric] The dielectric according to this embodiment is a layer disposed on a metal layer. In one aspect, the dielectric may be in contact with the metal layer, or may not be in contact with the metal layer via another layer. The dielectric constant of the dielectric according to this embodiment is preferably 2 or more, or 2.5 or more, or 3 or more, from the viewpoint of generating a desired phase shift in electromagnetic waves, for example, in electromagnetic wave control applications. The dielectric constant of the dielectric according to this embodiment is preferably 100 or less, or 50 or less, or 30 or less, or 10 or less, or 5 or less, from the viewpoint of reducing energy loss of electromagnetic waves, for example, in electromagnetic wave control applications. The dielectric constant of the dielectric is measured by a method described in the Examples. The water absorption of the dielectric is preferably 0.2 or less, or 0.15 or less, or 0.1 or less, from the viewpoint of suppressing changes in dielectric constant and dimensional changes due to water absorption and attenuation of transmitted electromagnetic waves. The water absorption of the dielectric is measured by a method described in the Examples.

[0017] The dielectric material according to this embodiment may be a ceramic or a resin. Examples of the ceramic include oxides, carbides, nitrides, borides, and fluorides of one or more elements selected from silicon, silver, copper, gold, aluminum, magnesium, zinc, cobalt, nickel, lithium, platinum, palladium, tin, chromium, lead, hafnium, zirconium, bismuth, manganese, titanium, molybdenum, antimony, indium, gallium, calcium, rhodium, iridium, sodium, tungsten, ruthenium, potassium, cadmium, osmium, rubidium, tantalum, strontium, thorium, niobium, protactinium, rhenium, vanadium, barium, arsenic, antimony, lutetium, yttrium, lanthanum, neodymium, thulium, holmium, dysprosium, and germanium. In particular, oxides, carbides, nitrides, borides and fluorides of silicon, copper, aluminum and magnesium are preferred from the viewpoint of ease of molding into a three-dimensional curved surface.

[0018] Examples of resins include polyimide (PI), liquid crystal polyester (LCP), polyester (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.), polyethersulfone (PES), polycarbonate (PC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyacetal (POM), polyarylate (PAR), polyamide (PA) (PA6, PA66, etc.), polyamideimide (PAI), polyetherimide (PEI), polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyphenylene sulfide (PPS), polyetherketone (PEK), polyphthalamide (PPA), polyethernitrile (PENt), polybenzimidazole (PBI), polycarbodiimide, polysiloxane, polymethacrylamide, nitrile rubber, acrylic rubber, polyethylene tetrafluoride, epoxy resin, and phenolic resin. Examples of suitable rubbers include acrylic resins, melamine resins, urea resins, polymethyl methacrylate resins (PMMA), polybutene, polypentene, ethylene-propylene copolymers, ethylene-butene-diene copolymers, polybutadiene, polyisoprene, ethylene-propylene-diene copolymers, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymers, polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), phenol novolac, benzocyclobutene, polyvinylphenol, polychloroprene, polyoxymethylene, polysulfone (PSF), polyphenylsulfone resin (PPSU), cycloolefin polymers (COP), acrylonitrile-butadiene-styrene resins (ABS), acrylonitrile-styrene resins (AS), polytetrafluoroethylene resins (PTFE), and polychlorotrifluoroethylene (PCTFE). In particular, PI, LCP and epoxy resins are preferred from the viewpoint of ease of molding onto a three-dimensional curved surface.

[0019] In this embodiment, the thickness of the dielectric is preferably 75 nm or more, or 1 μm or more, or 3 μm or more, or 10 μm or more from the viewpoint of easily realizing a desired phase shift, and from the same viewpoint, is preferably 43 mm or less, or 20 mm or less, or 8 mm or less. The thickness of the dielectric is measured by the method described in the Examples.

[0020] [Metal Pattern Region] The metal pattern region according to this embodiment is disposed on the surface of a dielectric. In the present disclosure, a plurality of metal patterns may be disposed on the metal, and the shape and size thereof may be selected as desired. The metal pattern according to this embodiment may also be obtained by forming a pattern on the metal. In one aspect, the shape of the metal pattern is preferably rectangular or circular, and the size of the metal pattern is preferably such that one side (e.g., when the metal pattern is rectangular) and the diameter (e.g., when the metal pattern is circular) are 1 / 100 to 1 / 2 times the wavelength of the incident electromagnetic wave. The metal pattern region according to this embodiment is composed of the meta-atoms according to this embodiment described below.

[0021] In the present disclosure, the area of ​​the metal pattern region according to this embodiment is the area of ​​the four sides surrounding the periphery of the metal pattern region. From the viewpoint of enabling the electromagnetic waves emitted from the structure having a three-dimensional curved surface according to this embodiment to cover a wide area, the area of ​​the metal pattern region according to this embodiment is preferably 0.09 mm ２ or more, or 0.36 mm ２ or more, or 9 mm ２ From the viewpoint of ease of processing, the area of ​​the metal pattern region according to this embodiment is preferably 20 m ２ Less than or equal to 5m ２ Less than or equal to 0.02m ２ or less than 1100 mm ２ or less than 400 mm ２ or less, or 110 mm ２ The area of ​​the metal pattern region according to this embodiment is preferably 0.09 mm ２ More than 20m ２ More preferably, it is 0.36 mm or less. ２ More than 5m２ Below 9 mm, particularly preferably ２ More than 0.02m ２ In one aspect, from the viewpoint of enabling the electromagnetic waves emitted from the structure having a three-dimensional curved surface according to this embodiment to cover a wide area, the area of ​​the metal pattern region according to this embodiment is 100 mm ２ or more, or 1000 mm ２ or more, or 2500 mm ２ or more, or 5000 mm ２ or more, or 10,000 mm ２ In one aspect, from the viewpoint of ease of processing, the area of ​​the metal pattern region according to this embodiment is 100 m ２ or less, or 10m ２ Less than or equal to 1 m ２ Less than or equal to 0.5m ２ Less than or equal to 0.25m ２ The following is the result.

[0022] The area of ​​the metal pattern region according to this embodiment is measured by the following method. The area of ​​the metal pattern region according to this embodiment may be calculated by measuring the characteristic length of the surface surrounding the periphery of the metal pattern region (in one embodiment, the vertical and horizontal lengths of the metal pattern region) using an optical microscope, and is not particularly limited. In one embodiment, the area of ​​the metal pattern region is found by multiplying the vertical and horizontal lengths of the metal pattern region, respectively.

[0023] The metal constituting the metal pattern region according to this embodiment is not particularly limited, but examples thereof include silver, copper, gold, aluminum, magnesium, zinc, cobalt, nickel, lithium, platinum, palladium, tin, chromium, lead, hafnium, zirconium, bismuth, manganese, titanium, molybdenum, antimony, indium, gallium, calcium, rhodium, iridium, sodium, tungsten, ruthenium, potassium, cadmium, osmium, rubidium, tantalum, strontium, thorium, niobium, protactinium, rhenium, vanadium, barium, arsenic, antimony, lutetium, yttrium, lanthanum, neodymium, thulium, holmium, dysprosium, and germanium. From the viewpoint of ease of processing and improving the transmittance of electromagnetic waves, the metal pattern region of this embodiment preferably contains silver, copper, gold, platinum, aluminum, nickel, and iron, more preferably contains silver, copper, gold, platinum, and aluminum, and even more preferably contains silver, copper, and aluminum.

[0024] (Additional Layer) The structure having a three-dimensional curved surface according to this embodiment may further include an additional layer in addition to the dielectric and the metal pattern region present on the dielectric surface. For example, the structure having a three-dimensional curved surface according to this embodiment may have an antioxidant layer disposed so as to cover the exposed metal pattern region. Examples of the antioxidant layer include silicone resin, fluororesin, butyral resin, urethane resin, epoxy resin, acrylic resin, modified polyester, polyamide resin, polyolefin resin, and fluorinated acrylic resin. The presence of the antioxidant layer prevents oxidation of the metal pattern region due to contact with oxygen in the air, thereby enabling the electromagnetic wave control performance to be maintained for a longer period of time.

[0025] [Meta-atom] In the present disclosure, a meta-atom is a metal pattern that constitutes a metal pattern region according to this embodiment.

[0026] The shape of the meta-atom is not particularly limited and may be, for example, a polyhedron. The meta-atom may have an internal cavity. The surface of the meta-atom may be flat or curved. In one aspect of the present invention, the surface of the meta-atom preferably has a regular periodicity, from the viewpoint of improving adhesion to adjacent dielectrics or to an antioxidant layer additionally provided to prevent oxidation of the meta-atom. In the present disclosure, the term "the surface of the meta-atom has a regular periodicity" refers to a continuous structure, such as a concave-convex structure (hereinafter referred to as a "convex-concave structure") and a stepped structure, on the surface of the meta-atom. In one aspect, the regular periodicity of the surface of the meta-atom (e.g., the period of the concave-convex structure and the stepped structure) is preferably 3 μm or more, 5 μm or more, or 10 μm or more from the above viewpoint, and is preferably 1000 μm or less, 300 μm or less, or 150 μm or less from the above viewpoint. The surface period of the meta-atom according to this embodiment is measured by photographing a cross section of the structure with an electron microscope to obtain a microscopic image and detecting the surface of the meta-atom.

[0027] In the present disclosure, the uneven structure refers to a structure in which the difference in height between the convex portions and the concave portions is 0.01 μm or more. The boundary between the convex portions and the concave portions may be a clear step, or may be a wavy unevenness with a smooth slope. The difference in height between the convex portions and the concave portions is preferably 0.01 μm or more, or 0.05 μm or more, or 0.1 μm or more from the viewpoint of improving adhesion with adjacent dielectrics and an antioxidant film additionally provided to prevent oxidation of the meta-atom, and is preferably 1 μm or less, or 0.5 μm or less, or 0.2 μm or less from the viewpoint of increasing the mechanical strength of the meta-atom.

[0028] In the present disclosure, a stepped structure refers to a structure in which the height of steps periodically increases or decreases. The step height is preferably 0.01 μm or more, or 0.05 μm or more, or 0.1 μm or more from the viewpoint of improving adhesion to adjacent dielectrics or to an antioxidant film additionally provided to prevent oxidation of the meta-atom, and is preferably 1 μm or less, or 0.5 μm or less, or 0.2 μm or less from the viewpoint of increasing the mechanical strength of the meta-atom.

[0029] Since meta-atoms do not have a specific shape, the size of a meta-atom is expressed by the diameter of the smallest enclosing sphere of the meta-atom. In this disclosure, the smallest enclosing sphere of a meta-atom refers to the sphere with the smallest diameter that can contain the meta-atom.

[0030] From the viewpoint of efficiently exciting surface plasmons with incident electromagnetic waves, the diameter of the smallest encompassing sphere of the meta-atom is 3 μm or more and 430 mm or less, preferably 3 μm or more and 100 mm or less, or 50 μm or more and 1.5 mm or less, relative to the wavelength of the incident electromagnetic wave. The diameter of the smallest encompassing sphere of the meta-atom is preferably 10 μm or more, or 30 μm or more, or 50 μm or more, or 75 μm or more, or 100 μm or more, relative to the wavelength of the incident electromagnetic wave. From the above viewpoint, the diameter is preferably 200 mm or less, or 100 mm or less, or 85 mm or less, or 50 mm or less, or 15 mm or less, or 4 mm or less, or 2 mm or less, or 1.5 mm or less, or 1 mm or less, or 500 μm or less, or 400 μm or less. In one aspect, when there is variation in the diameter of the smallest encompassing sphere of the meta-atom, the average of the minimum and maximum diameters may be used as the diameter of the smallest encompassing sphere of the meta-atom. The diameter of the smallest enclosing sphere of a meta-atom is determined by photographing the meta-atom with an optical microscope, acquiring a microscopic image, and calculating the diameter through image processing using Image J. The diameter of the smallest enclosing sphere of a meta-atom can be adjusted as appropriate by changing the laser irradiation area, etc.

[0031] The size of a meta-atom can be appropriately designed depending on the wavelength of the electromagnetic waves incident on a structure having a three-dimensional curved surface. The incident electromagnetic waves may be microwaves to terahertz waves, and their wavelengths may be, for example, in the range of 10 μm to 430 mm or 30 μm to 1000 mm. From the viewpoint of efficiently exciting surface plasmons with the incident electromagnetic waves, the diameter of the smallest encompassing sphere of the meta-atom is preferably 0.02 times or more, 0.03 times or more, or 0.05 times or more the wavelength of the incident electromagnetic waves. From the above viewpoint, the diameter is preferably 1 time or less, 0.7 times or less, or 0.5 times or less the wavelength of the incident electromagnetic waves.

[0032] From the viewpoint of ease of forming the meta-atom, the volume resistivity of the meta-atom is preferably 1.5×10 －８ Ω·m or more, and from the viewpoint of suppressing the energy of the electromagnetic wave incident on the electromagnetic wave control element from being converted into thermal energy and being attenuated, preferably 1×10 －３ Ω・m or less, or 1×10 －４ Ω・m or less, or 1×10 －５ Ω・m or less, or 1×10 －６ It is Ω·m or less.

[0033] The metal element constituting the meta-atom is not particularly limited, but examples thereof include silver, copper, gold, aluminum, magnesium, zinc, cobalt, nickel, lithium, platinum, palladium, tin, chromium, lead, hafnium, zirconium, bismuth, manganese, titanium, molybdenum, antimony, indium, gallium, calcium, rhodium, iridium, sodium, tungsten, ruthenium, potassium, cadmium, osmium, rubidium, tantalum, strontium, thorium, niobium, protactinium, rhenium, vanadium, barium, arsenic, antimony, lutetium, yttrium, lanthanum, neodymium, thulium, holmium, dysprosium, and germanium. From the viewpoint of preventing attenuation of surface plasmons excited by electromagnetic waves, the metal elements constituting the meta-atom are preferably silver, copper, gold, platinum, aluminum, nickel, and iron, more preferably silver, copper, gold, platinum, and aluminum, and even more preferably silver, copper, and gold. Furthermore, from the viewpoint of improving adhesion between the meta-atom and adjacent dielectrics and an antioxidant layer additionally provided to prevent oxidation of the meta-atom, it is preferable that the metal elements constituting the meta-atom include copper.

[0034] In one embodiment of the present invention, the meta-atom contains metal and carbon. From the viewpoint of improving adhesion between the meta-atom and a dielectric, the content ratio of carbon to metal in the meta-atom (in one embodiment, the carbon / metal elemental concentration ratio of the meta-atom) is preferably 0.05 or more, or 0.1 or more, or 0.5 or more, or 1.0 or more, or 1.5 or more, or 2.0 or more. From the viewpoint of preventing attenuation of surface plasmons excited by electromagnetic waves, the carbon / metal elemental concentration ratio of the meta-atom is 6.0 or less, or 5.5 or less, or 5.0 or less. Examples of methods for controlling the carbon / metal elemental concentration ratio of the meta-atom within the above range include, for example, a method of producing a meta-atom by irradiating a composition containing an adjusted mixture ratio of a metal compound and an organic compound with energy such as heat, plasma, or electromagnetic waves. The carbon / metal elemental concentration ratio of the meta-atom can be determined by EDX analysis.

[0035] The thickness of the meta-atom according to this embodiment is preferably 50 nm or more, or 100 nm or more, from the viewpoint of efficiently exciting surface plasmons with incident electromagnetic waves. From the same viewpoint, the thickness of the meta-atom according to this embodiment is preferably 300 μm or less, or 200 μm or less, or 100 μm or less. The thickness of the meta-atom is measured by the method described in the Examples.

[0036] (Metal Compound Layer) From the viewpoint of improving the reflectance of the structure, the structure according to this embodiment preferably has a metal oxide layer (in one embodiment, a metal compound layer) at the boundary between the meta-atom and the dielectric layer. Furthermore, from the viewpoint of improving the reflectance of the structure, the meta-atom according to this embodiment preferably has a metal compound layer therein. From the viewpoint of improving the reflectance of the structure, the thickness of the metal compound layer according to this embodiment is preferably 40 nm or more, or 50 nm or more, or 75 nm or more, or 100 nm or more. From the same viewpoint, the thickness of the metal compound layer according to this embodiment is preferably 10 μm or less, or 5 μm or less, or 1 μm or less. The thickness of the metal compound layer according to this embodiment is measured by the method described in the Examples. From the viewpoint of improving the reflectance, the ratio of the thickness of the metal compound layer to the thickness of the meta-atom is preferably 0.01 or more, or 0.1 or more, or 0.15 or more, or 0.2 or more. From the same viewpoint, it is preferably 0.5 or less, or 0.3 or less. The thickness of the metal compound layer inside the meta-atom can be appropriately adjusted by manipulating the laser irradiation intensity, etc.

[0037] The metal compound constituting the metal compound layer according to this embodiment is not particularly limited, but examples thereof include oxides and nitrides of silver, copper, gold, aluminum, magnesium, zinc, cobalt, nickel, lithium, platinum, palladium, tin, chromium, lead, hafnium, zirconium, bismuth, manganese, titanium, molybdenum, antimony, indium, gallium, calcium, rhodium, iridium, sodium, tungsten, ruthenium, potassium, cadmium, osmium, rubidium, tantalum, strontium, thorium, niobium, protactinium, rhenium, vanadium, barium, arsenic, antimony, lutetium, yttrium, lanthanum, neodymium, thulium, holmium, dysprosium, and germanium. Copper is preferred as the metal element constituting the metal compound layer because it exists stably as a metal compound and can be reduced to a metal with little energy. From the same perspective, copper oxide is preferred as the metal compound. From the viewpoint of improving the reflectivity of the structure, it is preferable that the metal compound layer present inside the meta-atom contains a copper oxide layer. From the viewpoint of efficiently exciting surface plasmons by incident electromagnetic waves, it is preferable that the metal constituting the meta-atom and the metal compound layer according to this embodiment both contain copper.

[0038] [Resin Layer] The structure according to this embodiment preferably includes a resin layer on the outside of the metal pattern region according to this embodiment. Examples of resin layers according to this embodiment include silicone resins, fluororesins, butyral resins, urethane resins, epoxy resins, acrylic resins, modified polyesters, polyamide resins, polyolefin resins, fluorinated acrylic resins, and polyimides. The presence of the resin layer according to this embodiment prevents oxidation of the metal pattern region due to contact with oxygen in the air, thereby enabling electromagnetic wave control performance to be maintained for a longer period of time. Furthermore, the resin layer reduces the amount of moisture penetrating into the structure according to this embodiment and suppresses water absorption in the dielectric layer, thereby preventing a decrease in adhesion between the metal pattern layer and the dielectric layer according to this embodiment due to dimensional changes caused by water absorption. In particular, when the dielectric layer according to this embodiment is made of a resin with low water absorption, such as modified polyphenylene ether (m-PPE), the presence of the resin layer, combined with the effect of the resin layer, reduces the amount of water absorbed into the dielectric layer, enabling electromagnetic wave control performance to be maintained for a longer period of time.

[0039] (Operating Frequency) The operating frequency of the structure having a three-dimensional curved surface according to this embodiment may be in the visible light band to the terahertz wave band. From the viewpoint of suitability for high-speed communication applications, the operating frequency of the structure according to this embodiment is preferably 0.3 GHz or higher, or 0.7 GHz or higher, or 1.5 GHz or higher, or 3.6 GHz or higher, or 27 GHz or higher, or 92 GHz or higher, or 152 GHz or higher, or 287 GHz or higher. From the viewpoint of suppressing attenuation of electromagnetic waves, the operating frequency of the structure according to this embodiment is preferably 10 THz or lower, or 5 THz or lower, or 1 THz or lower. The operating frequency of the structure according to this embodiment is preferably 0.3 GHz or higher and 10 THz or lower, more preferably 0.7 GHz or higher and 5 THz or lower.

[0040] <Electromagnetic Wave Transmission / Reception System> One aspect of the present invention provides an electromagnetic wave transmission / reception system including the structure having a three-dimensional curved surface of the present embodiment and an electromagnetic wave oscillation antenna. The type and shape of the electromagnetic wave oscillation antenna are not particularly limited and may be selected appropriately depending on the purpose. Examples of the electromagnetic wave oscillation antenna include a microstrip antenna.

[0041] <Method for manufacturing a structure having a three-dimensional curved surface> The method for manufacturing a structure according to this embodiment is a method for manufacturing a structure including a dielectric and a metal pattern region on the dielectric surface, and includes a step of forming the metal pattern region on the dielectric surface.

[0042] [Step of forming a metal pattern region] In this step, a metal pattern region is formed on the surface of a dielectric. Examples of methods for forming the metal pattern region include a method of applying a metal precursor-containing composition to the surface of a dielectric to form a coating layer, and selectively irradiating the coating layer with light energy (light-baking method). The metal precursor contained in the coating layer may be fine particles, and the average particle diameter of the fine particles of the metal precursor is 1 nm or more and 100 nm or less, more preferably 1 nm or more and 50 nm or less, and even more preferably 1 nm or more and 20 nm or less. The smaller the particle diameter of the fine particles of the metal precursor, the more easily the particles are fused together by light energy irradiation, and the less attenuation of the electromagnetic waves resonating in the metal pattern, which is preferable.

[0043] In the photo-sintering method, light irradiation is used as the energy irradiation. A flash light method using a discharge tube such as xenon as a light source or a laser light method can be applied. These methods involve short-term exposure to high-intensity light, raising the temperature of the dielectric layer to a high temperature in a short period of time, and firing. This method involves reducing and sintering the metal precursors in the coating layer of the metal precursor-containing composition, integrating these, and decomposing the organic matter, thereby forming a metal pattern. When the photo-sintering method is performed by laser irradiation, firing and patterning can be performed simultaneously by irradiating the coating layer of the metal precursor-containing composition with the laser.

[0044] The flash light method uses a xenon discharge tube to instantly discharge the charge stored in a capacitor, generating a large amount of pulsed light, which is then irradiated onto a coating layer of a metal precursor-containing composition, instantaneously heating the metal precursor on and / or within the dielectric layer to a high temperature and converting it into a metal pattern. The amount of exposure can be adjusted by the light intensity, light emission time, light irradiation interval, and number of times.

[0045] Although the light source is different, the same effect as the flash light method can be obtained using a laser light source. In the case of a laser, in addition to the adjustment items of the flash light method, there is a degree of freedom in wavelength selection, and the emission wavelength can be selected taking into account the light absorption wavelength of the coating layer of the metal precursor-containing composition. In addition, exposure by beam scanning is possible, and there is a feature that the exposure range can be easily adjusted, such as selecting exposure to the entire coating layer or partial exposure. As the type of laser, a YAG (yttrium aluminum garnet) laser, a YVO (yttrium vanadate) laser, a Yb (ytterbium) laser, a semiconductor (GaAs, GaAlAs, GaInAs) laser, and a carbon dioxide laser can be used, and not only the fundamental wave but also higher harmonics can be extracted and used as necessary.

[0046] In particular, when using laser light, the emission wavelength is preferably 300 nm or more and 1500 nm or less, for example, 355 nm, 405 nm, 445 nm, 450 nm, 532 nm, 1056 nm, etc. are preferred. From the absorption region of the coating layer of the metal precursor-containing composition, laser wavelengths of 355 nm, 405 nm, 445 nm, 450 nm, and / or 532 nm are particularly preferred. By using a laser, a desired three-dimensional pattern can be freely created. By selecting such a wavelength, desired voids can be formed, making it easy to create a metal-containing film with a desired porosity. The porosity of the metal precursor-containing film can be controlled by adjusting the output and speed of the laser irradiated onto the coating film of the metal precursor-containing composition. For example, slowing the laser scanning speed contributes to reducing the porosity.

[0047] Selective irradiation of laser light can be performed, for example, by irradiating a coating film of the metal precursor-containing composition with a light beam through a mask in a laser light method, or by directly drawing a desired pattern on the coating film by beam scanning in a laser light method. The surface irradiated with the laser light may be flat or not flat, and may be, for example, a housing in which the substrate is a three-dimensional object. The exposure amount can be adjusted by the laser light intensity, emission time, laser light irradiation interval, and number of times. In one embodiment, in the laser-irradiated region of the coating film of the metal precursor-containing composition, it is preferable that a portion of the coating film of the metal precursor-containing composition remains as a metal compound layer at the boundary with the dielectric layer. The metal compound layer acts as a dielectric and has the effect of improving reflectance.

[0048] (Cleaning Step) After laser irradiation, a cleaning step may be performed to remove the unfired regions using an appropriate cleaning solution. In this case, only the fired regions are left on the dielectric surface. Alternatively, the cleaning step may be omitted, leaving the unfired regions along with the fired regions.

[0049] When cleaning is performed, a solvent capable of dispersing or dissolving a metal compound (e.g., copper oxide) can be used as a cleaning liquid. Specific examples include water, propylene glycol monomethyl ether acetate, 3-methoxy-3-methyl-butyl acetate, ethoxyethyl propionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2-pentanediol, 2-methylpentane-2,4-diol, 2,5-hexanediol, 2,4-heptanediol, 2-ethylhexane-1,3-diol, diethylene glycol, hexanediol, octanediol, triethylene glycol, tri-1,2-propylene glycol, glycerol, and ethylene glycol monohexyl ether. , diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl acetate, diethylene glycol monoethyl ether acetate, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, 2-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, 2-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, 1-hexanol, 2-hexanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, 2-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol, and acetone. The above solvents are suitable, particularly when the coating layer of the metal precursor-containing composition contains a dispersant, because they can effectively wash away the metal precursor.Particularly preferred solvents are water, ethanol, butanol, i-propanol, and acetone. A dispersant may be added to the cleaning solution. A preferred dispersant is a phosphorus-containing organic substance.

[0050] (Optional Plating Step) A plating step may be performed in which the metal pattern after laser irradiation is plated. The metal-containing film after the laser light irradiation step preferably has a porosity of 0.5% by volume or more. This porosity allows the plating solution to easily penetrate in the subsequent plating step, improving plating adhesion and resulting in good adhesion. The porosity is more preferably 0.7% by volume or more, more preferably 1.0% by volume or more, more preferably 1.5% by volume or more, more preferably 2.0% by volume or more, and more preferably 2.5% by volume or more. In addition, from the viewpoint of adhesion between the copper-containing film and the substrate, the porosity is preferably 60% by volume or less, more preferably 58% by volume or less, more preferably 55% by volume or less, more preferably 53% by volume or less, and more preferably 51% by volume or less.

[0051] <Degreasing Step> In one embodiment, the method of the present disclosure may further include a degreasing step of degreasing the metal-containing film. Examples of degreasing methods include UV methods and wet degreasing methods. The degreasing step increases the growth rate of subsequent plating, improving productivity. This step also contributes to reducing the porosity of the metal pattern after plating.

[0052] From the viewpoint of interlayer adhesion of the structure, the degreasing step is preferably carried out by immersing the structure in a degreasing solution containing a compound having an amino group. Examples of compounds containing an amino group include amino acids such as alanine, arginine, asparagine, cysteine, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine; alkylamines such as methylamine, dimethylamine, ethylamine, trimethylamine, diethylamine, triethylamine, propylamine, isopropylamine, and diisopropylamine; alkanolamines such as 2-aminoethanol, diethanolamine, triethanolamine, N-methylethanolamine, and N,N-dimethylethanolamine; polyamines such as ethylenediamine, diethylenetriamine, tetraethylenepentamine, tris(hydroxymethyl)aminomethane, m-xylylenediamine, p-xylylenediamine, and 1,3-bis(aminomethyl)cyclohexane; aminosulfonic acids such as taurine; aminothiols such as 2-aminoethanethiol; and nitrogen-containing heterocyclic compounds such as 3-picolylamine and 3-pyridinemethanol. From the viewpoint of contributing to the plating growth rate, 2-aminoethanol is particularly preferred.

[0053] The degreasing liquid may be a commercially available product, and specific examples thereof include ALC-009 (containing 2-aminoethanol as a compound having an amino group) manufactured by Uemura Kogyo Co., Ltd. and Cleaner Securigant 902 (containing 2-aminoethanol as a compound having an amino group) manufactured by Atotech Japan K.K.

[0054] The concentration of the compound containing an amino group in the degreasing solution is preferably 5 mmol / L or more, more preferably 10 mmol / L or more, and even more preferably 20 mmol / L or more, from the viewpoint of removing substances that inhibit the plating reaction. Furthermore, from the viewpoint of promoting the plating reaction, the concentration of the compound containing an amino group in the degreasing solution is preferably 100 mmol / L or less, more preferably 90 mmol / L or less, and even more preferably 80 mmol / L.

[0055] The immersion time of the structure in the degreasing solution is preferably 1 minute or more, more preferably 2 minutes or more, from the viewpoint of contributing to the plating growth rate. Furthermore, from the viewpoint of reducing damage to the dielectric, the immersion time of the structure in the degreasing solution is preferably 15 minutes or less, more preferably 10 minutes or less. Immersion under stirring is preferred from the viewpoint of uniform degreasing.

[0056] The immersion temperature is preferably 15° C. or higher, more preferably 30° C. or higher, and even more preferably 40° C. or higher, in order to enhance the effect of accelerating the plating growth rate. Furthermore, from the viewpoint of reducing damage to the dielectric, the immersion temperature is preferably 70° C. or lower, and more preferably 60° C. or lower.

[0057] After the degreasing step, it is preferable to wash the structure using a washing liquid. The washing liquid is preferably water. The temperature of the washing liquid is preferably 15°C or higher, more preferably 20°C or higher. Furthermore, from the viewpoint of reducing damage to the dielectric, the temperature of the washing liquid is preferably 70°C or lower, more preferably 60°C or lower. It is preferable to carry out a plating step after washing the structure.

[0058] In this step, plating is performed on the metal-containing film that has or has not been subjected to the degreasing step. Electrolytic plating or electroless plating is performed on the metal-containing film (in one embodiment, the metal pattern) of the structure obtained as described above, thereby obtaining a metal pattern having a plated layer (e.g., a plated copper layer) of a desired thickness.

[0059] In one aspect, the plating performed in this embodiment is electroless plating. In one aspect, electroless plating of a metal-containing film facilitates improving conductivity. Electroless plating can form a metal pattern composed of a metal compound layer and a plating layer. Electroless plating can easily form a thick metal pattern, making it particularly advantageous for manufacturing structures for applications requiring large currents. In one aspect, electroless plating is preferred from the viewpoint of its wide applicability to patterns, and is particularly preferred for metal patterns created by laser.

[0060] A typical electroless plating method can be applied to the electroless plating. For example, electroless plating is performed together with a degreasing step or a cleaning step. As the electroless plating bath, for example, a plating solution containing copper ions and a reducing agent can be used. By immersing the structure in the plating solution while bubbling air, the copper ions in the plating solution are reduced, and copper is precipitated on the surface of the reduced copper layer, forming a plated copper layer.

[0061] The electroless plating bath may contain, for example, a plating solution containing CuSO4 as a copper ion source, EDTA (ethylenediaminetetraacetic acid) or Rochelle salt as a complexing agent, and formaldehyde (CHO), potassium tetrahydrochloride, dimethylamine borane, glyoxylic acid, or phosphinic acid as a reducing agent. Commercially available plating solutions include Thrucup PEA-6 and Thrucup ELC-SP from Uemura Industries Co., Ltd., Melplate CU-390 and Melplate CU-5100P from Meltex Inc., OPC Copper HFS, OPC Copper NCA, and ATS Adcopper IW from Okuno Chemical Industries Co., Ltd., CUPOSIT328 and C4500 from Rohm and Haas Co., Ltd., Atotech MVTP1 and Printganth UPlus from Atotech Inc., and Cu-150 and Cu-510 from Japan MacDermid Co., Ltd.

[0062] An electroless plating solution is used for electroless plating. The electroless plating solution preferably contains EDTA (ethylenediaminetetraacetic acid). EDTA functions as a complexing agent, forming a highly stable complex with copper ions, which suppresses side reactions in the plating bath and stabilizes the plating bath. This is thought to contribute to preventing peeling of the coating film by ensuring uniform plating deposition. This contributes to the production of structures with excellent interlayer adhesion. Furthermore, EDTA is stable even in high-temperature solutions, which also contributes to accelerating the plating speed. The plating bath for electroless plating may further contain a surfactant.

[0063] The amount of EDTA in the electroless plating solution is preferably 7 g / L or more, or 10 g / L or more, or 15 g / L or more from the viewpoint of obtaining the advantages of EDTA well, and is preferably 50 g / L or less, or 45 g / L or less, or 40 g / L or less from the viewpoint of reducing impurities in the plating deposit and lowering electrical resistance. The temperature of the electroless plating bath is preferably 25 to 80°C, and more preferably 30 to 70°C or 35 to 65°C, from the viewpoint of achieving faster plating growth. The plating time is preferably 5 to 60 minutes, more preferably 5 to 50 minutes, and more preferably 10 to 40 minutes.

[0064] Electroless plating is preferably carried out using a plating solution having a copper concentration in the range of 1.5 g / L to 5.0 g / L. A concentration of 1.5 g / L or more is preferred to improve the plating rate, and a concentration of 5.0 g / L or less is preferred from the viewpoint of uniformity of the plated film. The copper concentration is more preferably 1.5 g / L to 4.0 g / L, even more preferably 1.8 g / L to 3.5 g / L, and even more preferably 2.0 g / L to 3.0 g / L.

[0065] In one embodiment, electrolytic plating may be performed after electroless plating. A typical electroplating method can be applied to electrolytic plating. For example, an electrode and a metal pattern to be plated are placed in a solution (plating bath) containing metal ions (e.g., copper ions). Then, a direct current is applied between the electrode and the metal pattern from an external direct current power supply. In one embodiment, a current can be applied to the metal pattern on the dielectric by connecting a jig (e.g., a clip) connected to one of a pair of electrodes of the external direct current power supply to the metal pattern. As a result, metal is precipitated on the surface of the metal pattern on the dielectric by reduction of the metal ions, forming a plated metal layer.

[0066] Examples of the electroplating bath that can be used include a copper sulfate bath, a copper borofluoride bath, a copper cyanide bath, and a copper pyrophosphate bath. From the viewpoints of safety and productivity, a copper sulfate bath and a copper pyrophosphate bath are preferred.

[0067] As the copper sulfate plating bath, for example, a sulfuric acid copper sulfate plating bath containing copper sulfate pentahydrate, sulfuric acid, and chlorine is preferably used. The concentration of copper sulfate pentahydrate in the copper sulfate plating bath is preferably 50 g / L or more, or 100 g / L or more, and preferably 300 g / L or less, or 200 g / L or less. The concentration of sulfuric acid is preferably 40 g / L or more, or 80 g / L or more, and preferably 160 g / L or less, or 120 g / L or less. The solvent for the plating bath is usually water. The temperature of the plating bath is preferably 20°C or more, or 30°C or more, and preferably 60°C or less, or 50°C or less. The current density during electrolysis is preferably 1 A / dm 2 or more, or 2 A / dm 2 or more, preferably 15 A / dm 2 or less than 10 A / dm 2 The following is the result.

[0068] A suitable copper pyrophosphate plating bath is, for example, a plating bath containing copper pyrophosphate and potassium pyrophosphate. The concentration of copper pyrophosphate in the copper pyrophosphate plating bath is preferably 60 g / L or more, or 70 g / L or more, and preferably 110 g / L or less, or 90 g / L or less. The concentration of potassium pyrophosphate is preferably 240 g / L or more, or 300 g / L or more, and preferably 470 g / L or less, or 400 g / L or less. The solvent for the plating bath is usually water. The pH of the plating bath is preferably 8.0 or more, or 8.2 or more, and preferably 9.0 or less, or 8.8 or less. Ammonia water or the like may be added to adjust the pH value. The temperature of the plating bath is preferably 20°C or more, or 30°C or more, and preferably 60°C or less, or 50°C or less. The current density during electrolysis is preferably 0.5 A / dm 2 or more, or 1 A / dm 2 or more, preferably 10 A / dm 2 or less, or 7 A / dm 2 The plating bath for electrolytic plating may further contain a surfactant.

[0069] After the plating step, the structure is preferably washed using a washing liquid. The washing liquid is preferably water. The temperature of the washing liquid is preferably 15°C or higher, more preferably 20°C or higher. Furthermore, from the viewpoint of reducing damage to the dielectric, the temperature is preferably 70°C or lower, more preferably 60°C or lower.

[0070] After the plating step, it is preferable that the voids in the metal-containing film formed by the step of forming a metal pattern are reduced by 0.9% by volume or more. This improves adhesion between the metal-containing film formed by laser firing and the plating layer. The reduction rate is more preferably 1.0% by volume or more, more preferably 1.2% by volume or more, more preferably 1.5% by volume or more, and more preferably 2.0% by volume or more. From the viewpoint of ease of forming the metal-containing film, the reduction rate may be, for example, 60% by volume or less, 55% by volume or less, or 50% by volume or less.

[0071] The thickness of the plating layer (in one embodiment, the plated copper layer) is preferably 1 μm or more and 100 μm or less, more preferably 1 μm or more and 50 μm or less, and even more preferably 2 μm or more and 30 μm or less, from the viewpoint of efficient interaction of the metal pattern with electromagnetic waves.

[0072] The following examples further illustrate exemplary embodiments of the present invention, but the present invention is not limited to these examples.

[0073] [Evaluation method] [Test to confirm function as metamaterial] Using an HFSS manufactured by ANSYS, the reflection direction was calculated when an electromagnetic wave with a frequency of 300 GHz was incident on the metal pattern region of the structure from a direction of 0° as shown in Figure 2. The polarization direction of the electric field of the electromagnetic wave was set perpendicular to the width direction of the metal pattern. If the electromagnetic wave incident on the structure was reflected in an abnormal direction, the structure was determined to function as a metamaterial.

[0074] (Relative Permittivity) The relative permittivity of the dielectric was calculated from the time waveform of the transmitted electric field when an electromagnetic wave of 100 GHz was transmitted through the dielectric using a TAS7500SL manufactured by Advantest Corporation.

[0075] (Water Absorption Rate) The water absorption rate of the dielectric is measured by the dry weight method in accordance with Method A of JIS K7209 using a sample having the same dimensions as Type D1 of ISO 294-3.

[0076] (Thickness) The thicknesses of the metal layer, dielectric, and metal (copper) pattern (Meta-Atom) were determined by the following method. The structures produced in the examples were consolidated in epoxy resin, and then cross-sections were processed using an FIB device (product name Ethos NX5000, manufactured by Hitachi High-Technologies Corporation) to prepare samples. The thicknesses of each were determined by measuring microscopic images of the cross-sections of the samples taken using an electron microscope (product name S4800, manufactured by Hitachi High-Technologies Corporation). The thickness of the metal compound layer inside the Meta-Atom was determined by consolidating the structure in epoxy resin, cross-section processing using an FIB device (product name Ethos NX5000, manufactured by Hitachi High-Technologies Corporation) to enable cross-sectional analysis by SEM, and then setting the magnification so that the thickness of the Meta-Atom was within the field of view. The elemental composition within that range was analyzed using EDX (product name S4800, manufactured by Hitachi High-Technologies Corporation) at an accelerating voltage of 5 kV to calculate the element concentration.

[0077] (Diameter of the Smallest Enclosing Sphere of a Meta-Atom) The diameter of the smallest enclosing sphere of a meta-atom was determined by photographing the metal (copper) pattern with an optical microscope to obtain a microscopic image, and then calculating the diameter through image processing using Image J.

[0078] Example 1 (Fabrication of Structure) A copper sphere with a radius of 41.3 mm was dip-coated with U-imide varnish (manufactured by Unitika Ltd.) and cured at 280°C for 1 hour. The thickness of the cured product (dielectric 12) on the copper sphere was 25 μm, and the relative dielectric constant was 3.0. 202 g of copper (II) acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in a mixed solvent of 1,890 g of distilled water (manufactured by Kyoei Pharmaceutical Co., Ltd.) and 874 g of 1,2-propylene glycol (manufactured by Kanto Chemical Co., Ltd.), and the liquid temperature was adjusted to -5°C using an external temperature controller. 59 g of hydrazine monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the resulting solution over 20 minutes, and the mixture was stirred for 30 minutes under a nitrogen atmosphere. After that, the liquid temperature was adjusted to 25°C using an external temperature controller, and the mixture was stirred for 90 minutes. After stirring, the resulting dispersion was separated into a supernatant and a precipitate by centrifugation. To 98 g of the obtained precipitate, a mixture of 13 g of DISPERBYK-145 (manufactured by BYK-Chemie) as a nonvolatile organic compound and 212 g of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was dispersed using a homogenizer, yielding 323 g of a composition with a cuprous oxide particle concentration of 20% by mass. The cured product was dip-coated with the obtained composition and dried in an oven at 60°C for 2 hours, resulting in a dried composition with a thickness of 800 nm. The dried composition was irradiated with 355 nm laser light in regions 11 of a metal (copper) pattern as shown in Table 1 with reference to Figure 1. Portions of the dried composition that were not irradiated with the laser and remained as the dried composition were wiped off with a nonwoven cloth impregnated with ethanol.

[0079] As shown in FIG. 2 , the metal (copper) pattern region 11 includes metal (copper) patterns (meta-atoms, in one embodiment) 13 arranged at regular intervals on the surface of the dielectric 12, designated #1 to #52. Also, as shown in FIG. 2 , in a cross-sectional plane at the equator of the copper sphere (structure 10), the angle between the incident wave and a straight line connecting the center of the copper sphere and #1 of the metal (copper) pattern 13 is 12.6°. As shown in FIG. 1 , the metal pattern region 11 includes a metal (copper) pattern 13, which is a rectangular parallelepiped copper layer having a vertical length of 110 μm and a horizontal length L, and is regularly arranged in repeating units with a vertical period of 150 μm and a horizontal period of 350 μm. A structure 10 was fabricated by arranging this metal (copper) pattern 13 and metal pattern region 11 as shown in FIG. 1 . The diameter of the smallest encompassing sphere of the meta-atom in the fabricated structure 10 was a minimum of 74.7 μm and a maximum of 345 μm. The thickness of the metal (copper) pattern 13 was 400 nm. Table 1 shows the horizontal length L of the metal (copper) patterns 13 (#1 to #52).

[0080]

[0081]

[0082] For the metal (copper) pattern region 11 of this structure 10, an ANSYS HFSS was used to calculate the reflection direction when an electromagnetic wave with a frequency of 300 GHz was incident on the copper pattern region from a 0° direction as shown in FIG. 2 . The polarization direction of the electric field of the electromagnetic wave was perpendicular to the vertical direction of the metal (copper) pattern 13. The results are shown in FIG. 3 . Note that the vertical axis of FIG. 3 represents a value proportional to the electromagnetic wave intensity (unit: none), and the horizontal axis of FIG. 3 represents the angle of the reflection direction (unit: degrees). On the horizontal axis of FIG. 3 , reflection to the left in FIG. 2 is negative, and reflection to the right in FIG. 2 is positive. From the results in FIG. 3 , it was confirmed that an incident wave at 0° was abnormally reflected at 45° to the right, as shown in FIG. 2 . It was found that the structure of Example 1 can function as a metamaterial because it can control the direction of electromagnetic waves in directions that cannot be achieved by normal specular reflection or refraction.

[0083] Example 2 (Preparation of Metal Compound-Containing Composition) 202 g of copper (II) acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in a mixed solvent of 1,890 g of distilled water (manufactured by Kyoei Pharmaceutical Co., Ltd.) and 874 g of 1,2-propylene glycol (manufactured by Kanto Chemical Co., Ltd.), and the liquid temperature was adjusted to -5°C using an external temperature regulator. 59 g of hydrazine monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the resulting solution over 20 minutes, and the mixture was stirred for 30 minutes under a nitrogen atmosphere. After that, the liquid temperature was adjusted to 25°C using an external temperature regulator, and the mixture was stirred for 90 minutes. After stirring, the resulting dispersion was separated into a supernatant and a precipitate by centrifugation. To 98 g of the obtained precipitate, a mixed liquid of 17 g of DISPERBYK-145 (manufactured by BYK-Chemie) as a nonvolatile organic substance and 100 g of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was dispersed using a homogenizer, thereby obtaining 216 g of a metal compound-containing composition containing cuprous oxide particles at a mass concentration of 30%.

[0084] (Fabrication of Structure) Referring to FIGS. 4 and 5 , a structure 10 was fabricated. A metal compound-containing composition was applied by spin coating to the spherical surface of a plano-convex spherical glass lens LA1257 (Thorlab Japan Co., Ltd.) serving as a substrate 16. The substrate was heated and baked in an IR furnace under a nitrogen-hydrogen mixed gas (hydrogen concentration: 3.6% by volume) at 320°C for 120 minutes to reduce copper oxide, producing a copper layer serving as a metal layer 15. Polyimide varnish (U-Imide Varnish CR, manufactured by Unitika Ltd.) was then applied by spin coating to the copper layer and cured at 300°C for 1 hour using a hot plate in an air atmosphere to form a polyimide layer serving as a dielectric 12. The polyimide layer had a dielectric constant of 3.0. A metal compound-containing composition was then applied by spin coating to the polyimide layer using a spin coater at a rotation speed of 1400 rpm to form a coating film. Laser irradiation (laser irradiation intensity: 30 mW) of the coating film formed multiple metal patterns 13 (metaatoms). The excess metal compound-containing coating film in the non-laser-irradiated areas was removed by pouring purified water over it, completing structure 10. The thicknesses of the copper layer as the metal layer, the polyimide layer as the dielectric, and the copper as the meta-atom formed on the spherical surface of glass lens LA1257 were 1 μm, 25 μm, and 0.4 μm, respectively. The diameter of the smallest encompassing sphere of the meta-atom of the fabricated structure 10 was a minimum of 147 μm and a maximum of 348 μm.

[0085] FIG. 4 is a top view of the structure produced in Example 2.

[0086] (Simulation to confirm function as a metamaterial) For the structure produced in Example 2, a HFSS manufactured by ANSYS was used to calculate the reflection intensity distribution when an electromagnetic wave with a frequency of 300 GHz was incident from the positive direction of the z axis to the negative direction shown in Figure 4. The polarization direction of the electric field of the electromagnetic wave was set parallel to the y axis direction. The results are shown in Figures 6 and 7.

[0087] FIG. 6 shows the reflection intensity distribution in the xz plane, and FIG. 7 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 6 and 7 are values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes are the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 6 indicates that reflection in the positive direction of the y axis is positive and reflection in the negative direction of the y axis is negative, while the horizontal axis of FIG. 7 indicates that reflection in the positive direction of the x axis is positive and reflection in the negative direction of the x axis is negative. From the results of FIG. 6, it was confirmed that the reflected wave was reflected in a direction tilted 30.5° from the z axis on the xz plane, and from the results of FIG. 7, it was confirmed that the reflected wave was reflected in a direction tilted 30.5° from the z axis on the yz plane. The azimuth angle θ of the reflection direction ｒ and polar angle φ ｒ is defined as shown in FIG. 8, the angle on the horizontal axis of FIG. 6 is θ ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ) and the angle on the horizontal axis in FIG. 7 is expressed as arctan (tan φ ｒ sinθ ｒ Therefore, the reflected wave is expressed as (θ ｒ , φ ｒ ) = (45°, 40°) direction. It was found that the structure of Example 2 can control the direction of electromagnetic waves in directions that cannot be achieved by ordinary specular reflection or refraction, and therefore functions as a metamaterial.

[0088] (Test to Confirm Metamaterial Function) The directional control ability of the structure fabricated in Example 2 was measured by the following method when an electromagnetic wave with a frequency of 300 GHz was incident from the positive direction of the z-axis to the negative direction in FIG. 4 . A uni-traveling-carrier photodiode (manufactured by NTT Electronics) connected to a tunable wavelength laser diode (manufactured by Spectra Quest Labs) was used as the 300 GHz electromagnetic wave oscillator 33. A Fermi-level controlled barrier diode (manufactured by NTT Electronics) was used as the photodetector 31. Furthermore, the photodetector 31 was attached to a moving stage 30 (manufactured by Sigma Koki) so that it could be scanned. The apparatus was arranged with reference to FIG. 9 . An electromagnetic wave 34 (incident wave) was irradiated from the oscillator 33 to the structure of Example 2 held on a sample holder 32, and the electromagnetic wave intensity of the reflected wave 35 reflected by the structure of Example 2 was measured by the photodetector 31. As a result, FIG. 10 showing the angular distribution of the reflection intensity was obtained. As shown in FIG. 10 , θ ｒ = 45°, φ ｒ Reflection at an angle of 45° was observed. This confirmed that the structure fabricated in Example 2 functions as a metamaterial.

[0089] [Example 3] (Preparation of metal compound-containing composition and structure) The metal compound-containing composition and structure prepared in Example 3 were prepared in the same manner as in Example 2, except that Figure 11 was used instead of Figure 4 and the curing conditions for the polyimide varnish were changed to a nitrogen atmosphere. The relative dielectric constant of the polyimide layer was 3.2. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 μm and a maximum of 348 μm.

[0090] (Simulation to Confirm Function as a Metamaterial) For the structure of Example 3, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 12 and 13. FIG. 12 shows the reflection intensity distribution in the xz plane, and FIG. 13 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 12 and 13 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 12 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 13 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 12 confirmed that the reflected wave was reflected in a direction tilted 45° from the z-axis on the xz plane, and the result of FIG. 13 confirmed that the reflected wave was reflected in a direction tilted 0° from the z-axis on the yz plane.

[0091] The angle on the horizontal axis in FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 45°) direction, and it was found that the material functions as a metamaterial because it can control the direction of electromagnetic waves in directions that cannot be achieved with normal specular reflection or refraction.

[0092] (Test to confirm function as metamaterial) The directional control ability when an electromagnetic wave with a frequency of 300 GHz was incident from the positive direction of the z axis shown in FIG. 11 to the negative direction was measured in the same manner as in Example 2. As a result, FIG. 14 showing the reflection intensity distribution was obtained. As shown in FIG. 14, the directional control ability when θ ｒ = -2°, φ ｒ Reflection at an angle of about 45° was observed. This confirmed that the structure fabricated in Example 3 functions as a metamaterial.

[0093] [Example 4] (Preparation of metal compound-containing composition and structure) The metal compound-containing composition and structure prepared in Example 4 were prepared in the same manner as in Example 3, except that Fig. 15 was referenced instead of Fig. 11. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 µm and a maximum of 348 µm.

[0094] (Simulation to Confirm Function as a Metamaterial) For the structure of Example 4, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 16 and 17 . FIG. 16 shows the reflection intensity distribution in the xz plane, and FIG. 17 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 16 and 17 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 16 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 17 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 16 confirmed that the reflected wave was reflected in a direction tilted 43.5° from the z-axis on the xz plane, and the result of FIG. 17 confirmed that the reflected wave was reflected in a direction tilted 10.5° from the z-axis on the yz plane.

[0095] The angle on the horizontal axis in FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ) and the angle on the horizontal axis of FIG. 17 is expressed as arctan (tan φ ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (11°, 44°) direction, which means that the direction of electromagnetic waves can be controlled in directions that cannot be achieved with normal specular reflection or refraction, and it was found that the material functions as a metamaterial.

[0096] (Test to confirm function as metamaterial) The directional control ability when an electromagnetic wave with a frequency of 300 GHz was incident from the positive direction of the z axis shown in FIG. 15 to the negative direction was measured in the same manner as in Example 2. As a result, FIG. 18 showing the reflection intensity distribution was obtained. As shown in FIG. 18, the directional control ability when θ ｒ = 13°, φ ｒReflection was observed at around 47°. This confirmed that the structure fabricated in Example 4 functions as a metamaterial.

[0097] [Example 5] (Preparation of metal compound-containing composition and structure) The metal compound-containing composition and structure prepared in Example 5 were prepared in the same manner as in Example 3, except that Fig. 19 was referenced instead of Fig. 11. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 µm and a maximum of 348 µm.

[0098] (Simulation to confirm function as a metamaterial) For the structure of Example 5, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 20 and 21 . FIG. 20 shows the reflection intensity distribution in the xz plane, and FIG. 21 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 20 and 21 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 20 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 21 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 20 confirmed that the reflected wave was reflected in a direction tilted 30° from the z-axis on the xz plane, and the result of FIG. 21 confirmed that the reflected wave was reflected in a direction tilted 0° from the z-axis on the yz plane.

[0099] The angle on the horizontal axis in FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. 21 is expressed as arctan (tanφ ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 30°) direction, which means that the direction of electromagnetic waves can be controlled in directions that cannot be achieved with normal specular reflection or refraction, and it was found that this material functions as a metamaterial.

[0100] (Test to confirm function as metamaterial) The directional control ability when an electromagnetic wave with a frequency of 300 GHz was incident from the positive direction of the z axis shown in FIG. 19 to the negative direction was measured in the same manner as in Example 2. As a result, FIG. 22 showing the reflection intensity distribution was obtained. As shown in FIG. 22, the directional control ability when θ ｒ = -2°, φ ｒ Reflection was observed at around 28°. This confirmed that the structure fabricated in Example 5 functions as a metamaterial.

[0101] [Example 6] (Preparation of metal compound-containing composition and structure) The metal compound-containing composition and structure prepared in Example 6 were prepared in the same manner as in Example 3, except that Fig. 23 was referenced instead of Fig. 11. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 µm and a maximum of 348 µm.

[0102] (Simulation to Confirm Function as a Metamaterial) For the structure of Example 6, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 24 and 25 . FIG. 24 shows the reflection intensity distribution in the xz plane, and FIG. 25 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 24 and 25 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 24 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 25 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 24 confirmed that the reflected wave was reflected in a direction tilted 29° from the z-axis on the xz plane, and the result of FIG. 25 confirmed that the reflected wave was reflected in a direction tilted 7.5° from the z-axis on the yz plane.

[0103] The angle on the horizontal axis in FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. 25 is expressed as arctan (tan φ ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ) = (13°, 30°) direction, which means that the direction of electromagnetic waves can be controlled in directions that cannot be achieved with normal specular reflection or refraction, and it was found that the material functions as a metamaterial.

[0104] [Example 7] (Preparation of Metal Compound-Containing Composition and Structure) The metal compound-containing composition and structure prepared in Example 7 were prepared using the same procedure as in Example 5, except that the laser irradiation intensity on the coating film of the metal compound-containing composition was reduced to 25 mW. The thickness of the copper meta-atom was 0.4 μm. A copper oxide layer as a metal compound layer was formed at the interface between the meta-atom and the dielectric, with a thickness of 0.05 μm. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 μm and a maximum of 348 μm.

[0105] (Simulation to Confirm Function as a Metamaterial) For the structure of Example 7, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 26 and 27 . FIG. 26 shows the reflection intensity distribution in the xz plane, and FIG. 27 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 26 and 27 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 26 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 27 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 26 confirmed that the reflected wave was reflected in a direction tilted 30° from the z-axis on the xz plane, and the result of FIG. 27 confirmed that the reflected wave was reflected in a direction tilted 0° from the z-axis on the yz plane.

[0106] The angle on the horizontal axis of FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ) = (0°, 30°), which means that the direction of the electromagnetic wave can be controlled in directions that cannot be achieved by ordinary specular reflection or refraction, and it was found that it functions as a metamaterial. Comparing Figure 26 with Figure 20, the value on the vertical axis of the peak is 3.27 × 10 ―５ From 3.33 x 10 ―５ 27 and 21, it is found that ―６ From 6.67 x 10 ―６ This indicates that the copper oxide layer inside the meta-atom improves reflectivity.

[0107] [Example 8] (Preparation of Metal Compound-Containing Composition and Structure) The metal compound-containing composition and structure prepared in Example 8 were prepared using the same procedure as in Example 5, except that the laser irradiation intensity on the coating film of the metal compound-containing composition was reduced to 22 mW. The thickness of the copper meta-atom was 0.4 μm. A copper oxide layer as a metal compound layer was formed at the interface between the meta-atom and the dielectric, with a thickness of 0.075 μm. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 μm and a maximum of 348 μm.

[0108] (Simulation to confirm function as a metamaterial) For the structure of Example 8, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 28 and 29 . FIG. 28 shows the reflection intensity distribution in the xz plane, and FIG. 29 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 28 and 29 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 28 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 29 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 28 confirmed that the reflected wave was reflected in a direction tilted 30° from the z-axis on the xz plane, and the result of FIG. 29 confirmed that the reflected wave was reflected in a direction tilted 0° from the z-axis on the yz plane.

[0109] The angle on the horizontal axis of FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ), and the angle on the horizontal axis of FIG. ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 30°), which means that the direction of the electromagnetic wave can be controlled in directions that cannot be achieved by ordinary specular reflection or refraction, and it was found that it functions as a metamaterial. Comparing Figure 28 with Figure 20, the value on the vertical axis of the peak is 3.27 × 10 ―５ From 3.37 x 10 ―５ 29 and 21, it is found that ―６ From 6.64 x 10 ―６ This indicates that the copper oxide layer inside the meta-atom improves reflectivity.

[0110] [Example 9] (Preparation of Metal Compound-Containing Composition and Structure) The metal compound-containing composition and structure prepared in Example 9 were prepared using the same procedure as in Example 5, except that the spin-coating rotation speed of the metal compound-containing composition was reduced to 1000 rpm and the laser irradiation intensity on the coating film of the metal compound-containing composition was increased to 34 mW. The thickness of the copper meta-atom was 0.48 μm. A copper oxide layer as a metal compound layer was formed at the interface between the meta-atom and the dielectric, with a thickness of 0.12 μm. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 147 μm and a maximum of 348 μm.

[0111] (Simulation to confirm function as a metamaterial) For the structure of Example 9, a calculation of the reflection intensity distribution was performed in the same manner as in Example 2. The results are shown in FIGS. 30 and 31 . FIG. 30 shows the reflection intensity distribution in the xz plane, and FIG. 31 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 30 and 31 represent values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes represent the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 30 represents reflection in the positive direction of the y-axis as positive and reflection in the negative direction of the y-axis as negative, while the horizontal axis of FIG. 31 represents reflection in the positive direction of the x-axis as positive and reflection in the negative direction of the x-axis as negative. The result of FIG. 30 confirmed that the reflected wave was reflected in a direction tilted 30° from the z-axis on the xz plane, and the result of FIG. 31 confirmed that the reflected wave was reflected in a direction tilted 0° from the z-axis on the yz plane.

[0112] The angle on the horizontal axis of FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. 31 is expressed as arctan (tanφ ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 30°), which means that the direction of the electromagnetic wave can be controlled in directions that cannot be achieved by ordinary specular reflection or refraction, and it was found that it functions as a metamaterial. Comparing Figure 30 with Figure 20, the value on the vertical axis of the peak is 3.27 × 10 ―５ From 3.37 x 10 ―５ 31 and 21, it is 6.63×10 ―６ From 6.76 x 10 ―６ This indicates that the copper oxide layer inside the meta-atom improves reflectivity.

[0113] [Example 10] (Preparation of metal compound-containing composition and structure) The metal compound-containing composition and structure prepared in Example 10 were prepared in the same manner as in Example 3, except that Fig. 32 was referenced instead of Fig. 11. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 10 was a minimum of 43 µm and a maximum of 95 µm.

[0114] (Simulation to confirm function as a metamaterial) For the structure produced in Example 10, a HFSS manufactured by ANSYS was used to calculate the reflection intensity distribution when an electromagnetic wave with a frequency of 1.05 THz was incident from the positive direction of the z-axis to the negative direction shown in FIG. 32 . The results are shown in FIGS. 33 and 34 . FIG. 33 shows the reflection intensity distribution in the xz plane, and FIG. 34 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 33 and 34 are values ​​proportional to the electromagnetic wave intensity (units: none), and the horizontal axes are the angle of the reflection direction (units: degrees). The horizontal axis of FIG. 33 indicates that reflection in the positive direction of the y-axis is positive and reflection in the negative direction of the y-axis is negative, while the horizontal axis of FIG. 34 indicates that reflection in the positive direction of the x-axis is positive and reflection in the negative direction of the x-axis is negative. The results in Figure 33 confirm that the reflected wave is reflected in a direction tilted 30.5° from the z-axis on the xz plane, and the results in Figure 34 confirm that the reflected wave is reflected in a direction tilted 0° from the z-axis on the yz plane.

[0115] The angle on the horizontal axis of FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. 34 is expressed as arctan (tanφ ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 30.5°), which makes it possible to control the direction of electromagnetic waves in directions that cannot be achieved with normal specular reflection or refraction, and therefore it was found to function as a metamaterial.

[0116] [Example 11] (Preparation of metal compound-containing composition / structure) The metal compound-containing composition structure prepared in Example 11 was prepared in the same manner as in Example 3, except that Fig. 35 was referenced instead of Fig. 11. The diameter of the smallest encompassing sphere of the meta-atom of the prepared structure 11 was a minimum of 345 µm and a maximum of 1082 µm.

[0117] (Simulation to confirm function as a metamaterial) For the structure produced in Example 11, a HFSS manufactured by ANSYS was used to calculate the reflection intensity distribution when an electromagnetic wave with a frequency of 100 GHz was incident from the positive direction of the z-axis shown in FIG. 35 to the negative direction. The results are shown in FIGS. 36 and 37. FIG. 36 shows the reflection intensity distribution in the xz plane, and FIG. 37 shows the reflection intensity distribution in the yz plane. The vertical axes of FIGS. 36 and 37 are values ​​proportional to the electromagnetic wave intensity (unit: none), and the horizontal axes are the angle of the reflection direction (unit: degrees). The horizontal axis of FIG. 36 indicates that reflection in the positive direction of the y-axis is positive and reflection in the negative direction of the y-axis is negative, while the horizontal axis of FIG. 37 indicates that reflection in the positive direction of the x-axis is positive and reflection in the negative direction of the x-axis is negative. The results in Figure 36 confirm that the reflected wave is reflected in a direction tilted 30.5° from the z-axis on the xz plane, and the results in Figure 37 confirm that the reflected wave is reflected in a direction tilted 0° from the z-axis on the yz plane.

[0118] The angle on the horizontal axis of FIG. ｒ , φ ｒ Using arctan (tanφ ｒ cosθ ｒ ), and the angle on the horizontal axis of FIG. ｒ sinθ ｒ ) and the reflected wave is expressed as (θ ｒ , φ ｒ ) = (0°, 30.5°), which makes it possible to control the direction of electromagnetic waves in directions that cannot be achieved with normal specular reflection or refraction, and therefore it was found to function as a metamaterial.

[0119] The structure according to the present invention has a three-dimensional curved surface, and therefore can be suitably applied to electromagnetic wave control elements in particular.

[0120] REFERENCE SIGNS LIST 10 Structure 11 Metal pattern region 12, 17 Dielectric 13 Metal pattern (meta-atom) 15 Metal layer 16 Substrate 30 Moving stage 31 Photodetector 32 Sample holder 33 Oscillator 34 Electromagnetic wave 35 Reflected wave

Claims

1. A structure having a three-dimensional curved surface, comprising, in this order, a metal layer, a dielectric, and a metal pattern region on the surface of the dielectric, wherein the diameter of the smallest encompassing sphere of the meta-atoms constituting the metal pattern region is 3 μm or more and 100 mm or less.

2. The structure according to claim 1, further comprising a metal compound layer within said meta-atom.

3. The structure according to claim 1 or 2, wherein the metal constituting the meta-atom includes copper.

4. The structure of claim 2, wherein the metal constituting said meta-atom and said metal compound layer comprises copper.

5. The structure according to claim 1 or 2, further comprising a resin layer on the outside of the metal pattern region.

6. The structure according to claim 1 or 2, wherein the carbon / metal element concentration ratio of said meta-atom is 1.0 or more and 6.0 or less.

7. The structure according to claim 1 or 2, wherein the dielectric has a water absorption coefficient of 0.2 or less.

8. The area of ​​the metal pattern region is 0.09 mm ２ More than 20m ２ 3. The structure of claim 1 or 2, wherein:

9. The structure according to claim 1 or 2, wherein the operating frequency is 0.3 GHz or more and 10 THz or less.

10. An electromagnetic wave transmitting and receiving system comprising the structure according to claim 1 or 2 and an electromagnetic wave oscillating antenna.

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