Metasurface sheet and window structure

Abstract

To provide a metasurface sheet and a window structure that can improve the electromagnetic wave transmission or blocking performance while using a metal layer as is without processing it.SOLUTION: A metasurface sheet 40 is attached to a window material 1 having at least one transparent plate 2 and a metal layer 3 laminated on the at least one transparent plate 2. The metasurface sheet 40 includes a substrate 42 and a metal pattern 41 formed on the substrate 42. The metal pattern 41 has a first region 411 made of a conductor and a second region 412 made of a conductor and spaced apart from the first region 411 and having a smaller area than the first region 411. The minimum distance between the first region 411 and the second region 412 is greater than 0 mm and less than 1 mm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a metasurface sheet and a window structure. [Background technology]

[0002] Patent Document 1 discloses a conventional window structure. The glass body in Patent Document 1 has a Low-E film formed on the entire surface of one side of the glass plate. It is known that a glass body with a Low-E film formed thereon has low transmittance to radio waves in a wide frequency band. For this reason, in Patent Document 1, a portion of the Low-E film is removed by laser processing to form a radio wave-transmitting region. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-113772 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the process of removing a portion of the Low-E film when manufacturing the glass body was not very manufacturable.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a metasurface sheet and window structure that can improve the electromagnetic wave transmission or blocking performance while using the metal layer as is without processing it. [Means for solving the problem]

[0006] To achieve the above object, the present invention includes the following subject matter.

[0007] Item 1. A metasurface sheet attached to a window material having at least one transparent plate and a metal layer laminated on the at least one transparent plate, A substrate; a metal pattern formed on the substrate; Equipped with The metal pattern is a first region made of a conductor; a second region made of a conductor and arranged at a distance from the first region and having an area smaller than that of the first region; and A metasurface sheet, wherein the minimum distance between the first region and the second region is greater than 0 mm and less than 1 mm.

[0008] Item 2. The first region is a rectangular region, the second region is a plurality of rectangular regions arranged at intervals with respect to each side of the first region, In the second region, a length of a side facing the first region is equal to a length of a corresponding side of the first region, and a length of a side perpendicular to the side facing the first region is shorter than the length of the corresponding side. The metasurface sheet according to item 1.

[0009] Item 3. In the second region, the length of a side perpendicular to the side facing the first region is 50% or less of the length of the corresponding side of the first region. The metasurface sheet according to item 2.

[0010] Item 4. In the outer circumferential direction of the first region, there is a conductor-free region between adjacent second regions, where no conductor is formed. Item 2 or Item 3. The metasurface sheet according to item 2 or 3.

[0011] Item 5. The metasurface sheet is used in accordance with a predetermined frequency, The first region is a square region, and the length of one side of the first region is 1 / 10 of the wavelength of the frequency. Item 2 or Item 3. The metasurface sheet according to item 2 or 3.

[0012] Item 6. A window material having at least one transparent plate and a metal layer laminated on the at least one transparent plate; a metasurface portion provided on the window material; Equipped with The metasurface portion is a first region made of a conductor; a second region made of a conductor and arranged at a distance from the first region and having an area smaller than that of the first region; and A window structure, wherein the minimum distance between the first region and the second region is greater than 0 mm and less than 1 mm. [Effects of the Invention]

[0013] The metasurface sheet and window structure of the above-described aspect of the present invention have the advantage that they can improve the electromagnetic wave transmission or blocking performance while using the metal layer as is without processing it. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a window material according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a metasurface film according to an embodiment. [Figure 3] Fig. 3(A) is a front view of the metasurface film according to the embodiment, and Fig. 3(B) is an enlarged view of part A in Fig. 3(A). [Figure 4] FIG. 4 is a cross-sectional view of a metasurface film according to the first modified example. [Figure 5] FIG. 5 is a cross-sectional view of a metasurface film according to the second modified example. [Figure 6] FIG. 6 is a schematic diagram of a waveguide model used in the examples. [Figure 7] Fig. 7(A) is a graph showing the results of a numerical simulation, and Fig. 7(B) is an enlarged view of part B in Fig. 7(A). [Figure 8] FIG. 8 is a graph showing the results of the numerical simulation. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Embodiment> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A window structure 10 according to an embodiment of the present invention includes a window material 1 and a metasurface portion 4 provided on the window material 1.

[0016] The window material 1 is a partition fitted into an opening in a building. The window material 1 closes the opening. The window material 1 comprises at least one transparent plate 2 and a metal layer 3 laminated on the transparent plate 2.

[0017] The metasurface unit 4 utilizes a metamaterial structure to enhance the transmission or blocking (reflection) performance for electromagnetic waves in a specific frequency band. The metasurface unit 4 is formed, for example, in a sheet shape. In this specification, a sheet on which the metasurface unit 4 is formed is referred to as a metasurface sheet 40. Note that the term "sheet" here refers to a thin material whose thickness is 10% or less of the maximum length between its outer edges in a planar view and which has a large expanse. If the shape in a planar view is rectangular, the "maximum length between its outer edges in a planar view" refers to the length of the diagonal. Furthermore, if the shape in a planar view is circular, the "maximum length between its outer edges in a planar view" refers to the diameter. In this specification, the term "sheet" also includes membranes, foils, films, etc.

[0018] 3, the metasurface unit 4 has a first region 411 and a second region 412 made of a conductor formed on the same plane. The second region 412 is disposed at a distance from the first region 411 and is formed to have a smaller area than the first region 411. The minimum distance between the first region 411 and the second region 412 is set to be greater than 0 mm and less than 1 mm.

[0019] The window structure 10 according to this embodiment is configured in this manner, and therefore can improve the transmission or blocking (reflection) performance for electromagnetic waves in a specific frequency band, even if it has a window material 1 that blocks (including reflects) electromagnetic waves using the metal layer 3. Similarly, the metasurface sheet 40 according to this embodiment, when attached to a window material 1 that blocks electromagnetic waves using the metal layer 3, can improve the transmission or blocking (reflection) performance for electromagnetic waves in a specific frequency band.

[0020] In the metasurface unit 4, the specific frequency band of electromagnetic waves that can improve the transmission or blocking performance is preferably any radio wave in the range of 0.5 GHz to 60 GHz. In this embodiment, the transmission or blocking performance is set to be high in the 5G frequency bands (3 GHz to 5 GHz, 25 GHz to 30 GHz). However, there are no particular restrictions on the frequency band in which the transmission or blocking performance of the metasurface unit 4 is to be improved. The specific frequency band in which the transmission or blocking performance is to be improved can be set to a desired frequency band by changing the size and / or spacing of the first region 411 and the second region 412 in the metasurface unit 4.

[0021] Each element of the window structure 10 and metasurface sheet 40 according to the embodiment will be described in more detail below. In this specification, "parallel" refers not only to two lines, sides, surfaces, etc. that do not intersect even when extended, but also to two lines, sides, surfaces, etc. that intersect at an angle within a range of 10°. Furthermore, "orthogonal" refers to two lines, sides, surfaces, etc. that intersect at an angle within a range of 90°±10°.

[0022] [Window Material 1] In this embodiment, the window material 1 is a double-pane glass having a plurality of transparent plates 2. However, the window material 1 may also be a single-pane glass. In addition to the plurality of transparent plates 2 and the metal layer 3, the window material 1 includes a spacer 5 that maintains a distance between the plurality of transparent plates 2.

[0023] (Transparent plate 2) The transparent plate 2 is a transparent plate material. In this specification, "transparent" means that the light transmittance is 10% or more with respect to the peak wavelength of the light before incidence, preferably 50% or more, and more preferably 80% or more. In other words, "transparent" in this specification also includes "semi-transparent" in which the light transmittance is, for example, about 30% with respect to the peak wavelength of the light before incidence. In addition, the transparent plate 2 is not limited to being colorless and transparent, and may be colored.

[0024] The transparent plate 2 according to this embodiment is preferably a glass plate. Examples of glass plates include float glass, figured glass, frosted glass, wired glass, and tempered glass. However, in addition to glass plates, acrylic plates, polycarbonate plates, and the like may also be used as the transparent plate 2.

[0025] There are no particular limitations on the shape of the transparent plate 2. The shape of the transparent plate 2 may be, for example, rectangular in plan view, circular in plan view, pentagonal in plan view, hexagonal in plan view, elliptical in plan view, etc. Here, "plan view" means that the main surface of the transparent plate 2 is viewed from a direction perpendicular to the main surface.

[0026] 1, the multiple transparent plates 2 are arranged at regular intervals in the thickness direction of the window material 1. Of adjacent transparent plates 2, one transparent plate 2 may be referred to as the "first transparent plate 21" and the other transparent plate 2 may be referred to as the "second transparent plate 22."

[0027] A spacer 5 is disposed between the first transparent plate 21 and the second transparent plate 22. The spacer 5 maintains the distance between the two adjacent transparent plates 21, 22. The outer peripheries of the multiple transparent plates 2 are surrounded by a sealing material (not shown), and the space (heat insulating layer 6) between the two adjacent transparent plates 21, 22 is formed airtight. The heat insulating layer 6 is preferably filled with a heat insulating gas. Examples of the heat insulating gas include an inert gas such as argon gas. However, the heat insulating layer 6 may also be filled with air. The heat insulating layer 6 may also be a vacuum.

[0028] The first transparent plate 21 has a first surface 211 and a second surface 212. Similarly, the second transparent plate 22 has a first surface 221 and a second surface 222. The first surfaces 211, 221 are one of the surfaces (main surfaces) in the thickness direction of the transparent plate 2. The second surfaces 212, 222 are main surfaces opposite the first surfaces 211, 221. In this embodiment, the first surfaces 211, 221 refer to surfaces of adjacent transparent plates 2 that face each other (inner surfaces in the thickness direction of the window material 1), and the second surfaces 212, 222 refer to outer surfaces of the window material 1.

[0029] The window material 1 in this embodiment is a double glazing made up of two transparent plates 2, but it may also be a triple glazing made up of three transparent plates 2, or it may be made up of four or more transparent plates 2.

[0030] (metal layer 3) The metal layer 3 is laminated on the transparent plate 2 to improve the heat insulating properties of the window material 1. The metal layer 3 is preferably a Low-E film. There are no particular limitations on the Low-E film, and examples thereof include a film in which a transparent dielectric layer, an infrared reflective layer, and a transparent dielectric layer are laminated in this order. Examples of the transparent dielectric layer include metal oxides (e.g., zinc oxide, tin oxide) and metal nitrides. Examples of the infrared reflective layer include metal films (e.g., silver), semiconductor films, etc.

[0031] The metal layer 3 may be laminated on any one of the plurality of transparent plates 2. In this embodiment, the metal layer 3 is laminated on the first surface 211 of the first transparent plate 21. The metal layer 3 is laminated over the entire surface of the first surface 211 of the transparent plate 2. The metal layer 3 is laminated on the transparent plate 2 by, for example, coating, vapor deposition, adhesion, welding, or the like.

[0032] (window frame) A window frame (not shown) surrounds the periphery of the window material 1. It is preferable that the window material 1 is fitted into the window frame. The window frame is formed, for example, in a generally rectangular frame shape when viewed from the front. The window frame may also include a fixed frame that is fitted into the opening, and a movable frame that is movable relative to the fixed frame and into which the window material 1 is fitted. The movable frame may be movable relative to the fixed frame in a direction parallel to the opening surface, or in a direction intersecting the opening surface. The movable frame that moves in a direction intersecting the opening surface may be either a vertical-axis rotating window frame or a horizontal-axis rotating window frame. The window frame may also be a fixed window frame that is attached immovably to the opening.

[0033] The opening is, for example, an opening formed in a wall of a building. The building is not particularly limited, and examples thereof include non-residential buildings, residential buildings, and complex buildings that combine non-residential buildings and residential buildings. Examples of non-residential buildings include stores, office buildings, factories, warehouses, school buildings (kindergartens), and the like. The building may be constructed using any of a number of methods, such as reinforced concrete, steel reinforced concrete, steel frame, or wood construction.

[0034] Examples of the window structure 10 according to this embodiment include window glass for buildings, as well as light-receiving windows in doors, fixed windows in ceilings, floors, etc. Furthermore, the window structure 10 according to this embodiment can be applied to windows for automobiles, aircraft, ships, trains, ropeways, etc. in addition to buildings.

[0035] (Metasurface part 4) The metasurface unit 4 is provided on the window material 1. The metasurface unit 4 according to this embodiment is a metasurface sheet 40 attached to the first transparent plate 21 of the window material 1. However, the metasurface unit 4 is not limited to a sheet attached to the window material 1, and may be, for example, a pattern formed on one surface of the window material 1 by vapor deposition or the like. Furthermore, the metasurface sheet 40 may be attached to the second transparent plate 22 or the metal layer 3.

[0036] As shown in Figures 2 and 3, the metasurface sheet 40 comprises a substrate 42 attached to the transparent plate 2 or the metal layer 3, and a metal pattern 41 formed on the substrate 42. By attaching the metasurface sheet 40 to the transparent plate 2 or the metal layer 3, the window material 1 can be improved in terms of the transmission or blocking performance of electromagnetic waves in a specific frequency band. As shown in Figure 2, the metasurface sheet 40 is formed by laminating a substrate 42, multiple metal patterns 41, and a protective film 44 in this order. The metasurface sheet 40 of this embodiment is attached, for example, to the second surface 212 of the first transparent plate 21. The metasurface sheet 40 may cover the entire surface of the transparent plate 2, or may be attached to only a portion of the entire surface.

[0037] (Base material 42) The substrate 42 supports the metal pattern 41. In this embodiment, the substrate 42 is transparent. The substrate 42 is attached to the transparent plate 2 or the metal layer 3. An adhesive layer (hereinafter referred to as the first adhesive layer 45) is provided on the surface of the substrate 42 opposite to the metal pattern 41. The first adhesive layer 45 preferably has a large number of capsules filled with adhesive before bonding, and is structured so that when pressure is applied from the substrate 42 toward the transparent plate 2 or the metal layer 3 during bonding, the capsules rupture, allowing bonding. However, the first adhesive layer 45 may also be an adhesive that is applied without being filled into capsules. Examples of adhesives include synthetic resins such as acrylic resins, silicone resins, and polyvinyl alcohol resins.

[0038] In this embodiment, the outer shape of the substrate 42 is quadrangular (more specifically, square) in plan view, as shown in Fig. 3. However, there are no particular limitations on the shape of the substrate 42, and examples include a polygon, a circle, an ellipse, a star, a heart, and the like. The thickness of the substrate 42 is uniform over the entire surface. However, the thickness of the substrate 42 does not have to be uniform.

[0039] Examples of the substrate 42 include synthetic resins, FRP (Fiber Reinforced Plastics), carbon, and glass. Examples of the synthetic resin include one or more selected from the group consisting of PET (polyethylene terephthalate), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyformaldehyde, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin. The substrate 42 may be a composite material of these synthetic resins. The substrate 42 according to this embodiment is made of a PET film.

[0040] The thickness of the substrate 42 is, for example, preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. On the other hand, the upper limit of the thickness of the substrate 42 is, for example, preferably 500 μm or less, more preferably 130 μm or less, and even more preferably 100 μm or less.

[0041] The substrate 42 preferably has flexibility. The Young's modulus of the substrate 42 is, for example, preferably 0.01 GPa or more, more preferably 1 GPa or more, and even more preferably 8 GPa or more. On the other hand, the upper limit of the Young's modulus of the substrate 42 is, for example, preferably 80 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less.

[0042] (Metal pattern 41) The metal pattern 41 is a metal microstructure portion having a structure finer than the wavelength of a target electromagnetic wave (e.g., radio wave). One periodically formed figure in the metal pattern 41 corresponds to a split ring resonator in a metasurface (metamaterial) and is also called a split ring resonator (SRR). In this specification, one periodically formed figure in the metal pattern 41 may be referred to as a "resonator portion 414."

[0043] The metal pattern 41 is made of a conductor. The metal pattern 41 is formed on a substrate 42. Methods for forming the metal pattern 41 on the substrate 42 include, for example, laminating a thin film in which the metal pattern 41 is embedded in a thin-film dielectric on the substrate 42, or forming the metal pattern 41 on the substrate 42 without using a dielectric.

[0044] Examples of conductors constituting the metal pattern 41 include one or more of silver, gold, copper, platinum, aluminum, titanium, silicone, indium tin oxide, and alloys (e.g., alloys containing nickel, chromium, and molybdenum). Examples of alloys containing nickel, chromium, and molybdenum include various grades of Hastelloy B-2, B-3, C-4, C-2000, C-22, C-276, G-30, N, W, and X.

[0045] The thickness of the conductor is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 100 nm or more. On the other hand, the upper limit of the thickness of the conductor is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 4 μm or less. When the thickness of the conductor is 10 nm or more, appropriate radio wave intensity can be ensured.

[0046] The shape of each resonator portion 414 of the metal pattern 41 may take various shapes depending on the desired frequency band of radio waves for which transmission or blocking performance is to be improved, but in this embodiment, the pattern shown in Fig. 3 will be described as an example. By adjusting the shape and size of the resonator portion 414 in the metal pattern 41 according to this embodiment, it is possible to improve the transmission or blocking performance of electromagnetic waves in a desired frequency band.

[0047] 3(A)(B), each resonator unit 414 includes one first region 411 and four second regions 412. Each of the first region 411 and the second region 412 is partitioned by a region where no conductor is formed (sometimes referred to as a "conductor-free region"). The first region 411 and the second region 412 are spaced apart and are not electrically connected to each other.

[0048] The first region 411 is preferably a rectangular region made of a conductor. The first region 411 according to this embodiment is a square region. The entire first region 411 is made of a conductor. The length of one side of the first region 411 is preferably 1 / 10 of the wavelength of the desired frequency band. To give some examples, when the frequency of the electromagnetic wave incident on the metasurface sheet 40 (sometimes referred to as the "predetermined frequency") is 3 GHz, the length D1 of one side is 10 mm. When the predetermined frequency is 3.5 GHz, the length D1 of one side is 8.5 mm. When the predetermined frequency is 3.7 GHz, the length D1 of one side is 8.0 mm. When the predetermined frequency is 4.5 GHz, the length D1 of one side is 6.6 mm. When the predetermined frequency is 4.7 GHz, the length D1 of one side is 6.3 mm. When the predetermined frequency is 4.9 GHz, the length D1 of one side is 6.1 mm. When the predetermined frequency is 7 GHz, the length D1 of one side is 4.3 mm. However, the calculation is based on the propagation speed of electromagnetic waves being 299,792,458 m / s. In this specification, the "length of one side" is the length in millimeters, rounded to one decimal place.

[0049] When the first region 411 is a rectangular region, it is preferable that the longer of the vertical length and horizontal length is 1 / 10 of the wavelength of the predetermined frequency. Furthermore, when the first region 411 is a circular region, it is preferable that the diameter is 1 / 10 of the wavelength of the predetermined frequency. Furthermore, when the first region 411 is a polygon with five or more sides, it is preferable that the longest diagonal line among the multiple diagonals is 1 / 10 of the wavelength of the predetermined frequency. By configuring it in this way, it is possible to improve the transmission performance or blocking performance for the predetermined frequency.

[0050] Each second region 412 is disposed at an interval relative to each side of the first region 411. Each second region 412 is formed to have a smaller area than the first region 411. The second region 412 is preferably a rectangular region made of a conductor. The second region 412 according to this embodiment is a rectangular region in which one pair of sides is longer than the other pair of sides. All of the second region 412 is made of a conductor.

[0051] As shown in FIG. 3B , in the second region 412, the length D21 of a side H21 facing a side H1 of the first region 411 is preferably equal to the length D1 of the corresponding side H1 of the first region 411, and the length D22 of a side H22 perpendicular to the side H1 of the first region 411 is preferably shorter than the length D1 of the corresponding side H1 of the first region 411. In particular, the length D22 of the side H22 is preferably 50% or less of the length D1 of the side H1, more preferably 40% or less, and even more preferably 30% or less. The length D22 of the side H22 perpendicular to the side H1 of the first region 411 in the second region 412 is preferably 15% or more of the length D1 of the side H1. In this way, by changing the lengths D1, D21, and D22 of the regions 411 and 412, it is possible to adjust the desired frequency at which transmission or blocking performance is obtained.

[0052] The minimum distance between the first region 411 and the second region 412 is greater than 0 mm and less than 1 mm. This configuration allows a resonance point to be generated for electromagnetic waves of a desired frequency. The minimum distance between the first region 411 and the second region 412 is preferably 0.7 mm or less, more preferably 0.6 mm or less, and even more preferably 0.5 mm or less. The minimum distance between the first region 411 and the second region 412 is preferably 0.2 mm or more, and more preferably 0.3 mm or more. This makes it easier to generate a more pronounced resonance point for electromagnetic waves of a desired frequency.

[0053] Furthermore, it is preferable that a rectangular conductor-free region (hereinafter referred to as a corner-free region 413) is formed between adjacent second regions 412 in the circumferential direction of the first region 411. The corner-free region 413 is formed corresponding to the protruding corners of the first region 411, and in this embodiment, four corner-free regions 413 are formed in one resonator 414. For example, if the first region 411 is pentagonal, five corner-free regions 413 are formed corresponding to the protruding corners. This configuration makes it easier to produce a more pronounced resonance point for electromagnetic waves of a desired frequency.

[0054] The metal pattern 41 preferably has a relative dielectric constant of 7 or more. On the other hand, the upper limit of the relative dielectric constant is preferably 10,000 or less.

[0055] Furthermore, the shape of the resonator unit 414 of the metal pattern 41 is preferably a figure with four-fold or more rotational symmetry. When the resonator unit 414 has a figure with four-fold or more rotational symmetry, the dependency on the angle of the incident wave in a plan view is reduced. However, the shape of the resonator unit 414 may also have two-fold or three-fold symmetry.

[0056] (protective film 44) The protective film 44 can protect the metal patterns 41 by covering the multiple metal patterns 41. The protective film 44 has a size corresponding to the substrate 42 in a plan view. The protective film 44 is, for example, a film made of a synthetic resin. Examples of the synthetic resin include one or more selected from the group consisting of PET (polyethylene terephthalate), COP (cycloolefin polymer), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyformaldehyde, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin.

[0057] The protective film 44 preferably contains fluorine. The protective film 44 containing fluorine can prevent transmission of ultraviolet rays, and therefore can protect the plurality of metal patterns 41 from ultraviolet rays.

[0058] The thickness of the protective film 44 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. On the other hand, the upper limit of the thickness of the protective film 44 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 25 μm or less.

[0059] The protective film 44 is adhered to the base material 42 via an adhesive layer (hereinafter referred to as the second adhesive layer 43). Examples of the second adhesive layer 43 include a synthetic resin, a rubber adhesive sheet, etc. Examples of the synthetic resin include an acrylic resin, a silicone resin, and a polyvinyl alcohol resin.

[0060] <Modification> The above embodiment is merely one of various embodiments of the present invention. The embodiment can be modified in various ways depending on the design, etc., as long as the object of the present invention can be achieved. Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combinations.

[0061] (First Modification) In the above embodiment, multiple transparent plates 2 are provided, but as shown in FIG. 4, the window material 1 may have only one transparent plate 2. As shown in FIG. 4, a metal layer 3 is laminated on a first surface 211 of the transparent plate 2. A metasurface portion 4 is provided on the metal layer 3. Note that the metasurface portion 4 may also be provided on a second surface 212 on which no metal layer 3 is provided.

[0062] Furthermore, the metal layer 3 is not limited to a Low-E film and may be a heat-shielding film. When the metal layer 3 is a heat-shielding film, it may be attached to the first surface 211 or the second surface 212 of the transparent plate 2, for example, after the window material 1 is installed in a window frame.

[0063] (Second Modification) In the above embodiment, the metasurface portion 4 is attached to a transparent plate 2 (first transparent plate 21) on which a metal layer 3 is laminated, but as shown in Figure 5, it may also be provided on a transparent plate 2 (second transparent plate 22) other than the transparent plate 2 on which the metal layer 3 is laminated.

[0064] The distance between the metasurface section 4 and the metal layer 3 is preferably 110 mm or less, more preferably 30 mm or less, and even more preferably 10 mm or less. On the other hand, the lower limit of the distance between the metasurface section 4 and the metal layer 3 may be 0 mm. In other words, the metasurface section 4 may be directly bonded to the metal layer 3 (see FIG. 4).

[0065] <Example> In this example, it was confirmed by numerical simulation that the transmission or blocking performance of electromagnetic waves of a specific frequency can be improved by providing the metasurface portion 4 on the surface of the window material 1. The numerical simulation was performed based on a waveguide model 9 shown in FIG.

[0066] A metasurface sheet 40 having a metal pattern 41 (FIG. 3) of the embodiment was used in the metasurface section 4 included in the waveguide model 9. In the waveguide model 9, a test piece was used in which the metasurface sheet 40, the first transparent plate 21, the metal layer 3, the heat insulating layer 6, and the second transparent plate 22 were stacked in this order from top to bottom, and the radio wave intensity transmitted through the test piece was calculated.

[0067] 3, and the minimum distance between the first region 411 and the second region 412 were set under the conditions shown in Table 1. For Comparative Example 1, a test piece without a metasurface sheet (a test piece in which the first transparent plate 21, the metal layer 3, the heat insulating layer 6, and the second transparent plate 22 were laminated in this order) was used.

[0068] [Table 1] The frequency of the radio waves incident on the test piece was changed from 1 GHz to 6 GHz, and the difference in intensity between the incident wave and the outgoing wave was calculated for each frequency of the radio waves.

[0069] The calculation results are shown in Figures 7 and 8. Figure 7(B) is an enlarged view of part B in Figure 7(A). As can be seen from Figure 7(B), in Comparative Example 1, which does not have the metasurface sheet 40, the intensity was -63 dB at 4.7 GHz, whereas in Example 1 it was -60 dB and in Example 2 it was -58 dB. Therefore, it was confirmed that the test piece with the metasurface sheet 40 had easier transmission of radio waves at specific frequencies than the test piece without the metasurface sheet 40.

[0070] 8, in Example 1, a resonance point appears at 4.7 GHz, whereas no resonance point appears in Comparative Examples 2 and 3. From this, it was confirmed that when the minimum distance between first region 411 and second region 412 is less than 1 mm, a resonance point appears, thereby improving the blocking performance (reflection performance) for electromagnetic waves in a specific frequency band. [Explanation of symbols]

[0071] 10 Window Structure 1. Window materials 2 transparent plate 21 1st transparent plate 22 Second transparent plate 3 metal layer 4 Metasurface section 40 Metasurface Sheet 41 Metal Pattern 411 First area 412 Second area 413 Corner non-formation area 414 Resonance part 42 Base material

Claims

1. A metasurface sheet attached to a window material having at least one transparent plate and a metal layer laminated to the at least one transparent plate, A substrate; a metal pattern formed on the substrate; Equipped with The metal pattern is a first region made of a conductor; a second region made of a conductor and arranged at a distance from the first region and having an area smaller than that of the first region; and The minimum distance between the first region and the second region is greater than 0 mm and less than 1 mm. Metasurface sheet.

2. the first region is a rectangular region, the second region is a plurality of rectangular regions arranged at intervals with respect to each side of the first region, In the second region, a length of a side facing the first region is equal to a length of a corresponding side of the first region, and a length of a side perpendicular to the side facing the first region is shorter than the length of the corresponding side. The metasurface sheet according to claim 1.

3. In the second region, a length of a side perpendicular to a side facing the first region is 50% or less of a length of the corresponding side of the first region. The metasurface sheet according to claim 2.

4. a conductor-free region in which no conductor is formed is present between adjacent second regions in the circumferential direction of the first region; The metasurface sheet according to claim 2 or claim 3.

5. The metasurface sheet is used in accordance with a predetermined frequency, The first region is a square region, and the length of one side of the first region is 1 / 10 of the wavelength of the frequency. The metasurface sheet according to claim 2 or claim 3.

6. a window material having at least one transparent plate and a metal layer laminated to the at least one transparent plate; a metasurface portion provided on the window material; Equipped with The metasurface portion is a first region made of a conductor; a second region made of a conductor and arranged at a distance from the first region and having an area smaller than that of the first region; and The minimum distance between the first region and the second region is greater than 0 mm and less than 1 mm. Window structure.

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