Laminate structure

Abstract

To provide a laminate structure that can obtain electromagnetic wave transmission or blocking performance required for design while using a metal layer as it is without processing it.SOLUTION: A laminate structure 10 is configured such that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves below a predetermined frequency than for electromagnetic waves above a predetermined frequency, and includes a laminate 1 having at least one plate material 2 and a metal layer 3 laminated on the at least one plate material 2, and a metasurface sheet 4 attached to the laminate 1, and the metasurface sheet 4 is configured such that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves of the predetermined frequency or higher than for electromagnetic waves of below the predetermined frequency.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a laminated structure. [Background technology]

[0002] Patent Document 1 discloses a conventional laminated structure. The laminated structure of Patent Document 1 is a window structure having a glass body. The glass body of Patent Document 1 has a Low-E film formed on the entire surface of one surface 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 laminated structure that can obtain the electromagnetic wave transmission or blocking performance required for design 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 laminated structure configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves having a frequency equal to or lower than a predetermined frequency than for electromagnetic waves having a frequency higher than the predetermined frequency, a laminate having at least one plate material and a metal layer laminated on the at least one plate material; A metasurface sheet attached to the laminate; Equipped with The metasurface sheet is a laminated structure configured so that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves of a predetermined frequency or higher than that for electromagnetic waves of a predetermined frequency or lower.

[0008] Item 2. The metasurface sheet is A substrate; a metal pattern formed on the substrate, the metal pattern having a plurality of resonating units periodically formed thereon; and Each of the plurality of resonating units is a conductor region including an outer edge of the resonator portion; Item 2. The laminate structure according to item 1, further comprising: a conductor-free region that is a region inside the outer edge where no conductor is provided.

[0009] Item 3. The laminated structure according to Item 2, wherein the conductor region is composed of a plurality of linear bodies surrounding the conductor-free region.

[0010] Item 4. The laminated structure according to Item 3, wherein each of the resonator parts is formed in a rectangular shape, and the conductor of the metal pattern is formed in a lattice pattern.

[0011] Item 5. A laminated structure configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves of a predetermined frequency or higher than the predetermined frequency than for electromagnetic waves of a frequency lower than the predetermined frequency, a laminate having at least one plate material and a metal layer laminated on the at least one plate material; A metasurface sheet attached to the laminate; Equipped with The metasurface sheet is a laminated structure configured so that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves below a predetermined frequency than for electromagnetic waves above the predetermined frequency.

[0012] Item 6. The metasurface sheet is A substrate; a metal pattern formed on the substrate, the metal pattern having a plurality of resonating units periodically formed thereon; and The metal pattern is Item 7. The laminated structure according to item 6, wherein a plurality of conductor regions made of conductors are separated by conductor-free regions where no conductors are provided.

[0013] Item 7. The laminated structure according to Item 6, wherein the conductor-free region is in a lattice pattern.

[0014] Item 8. The plate material is window glass, Item 8. The laminate structure according to any one of items 1 to 7, wherein the metal layer is a Low-E film. [Effects of the Invention]

[0015] The laminated structure of the above aspect according to the present invention has an advantage that it is possible to obtain the electromagnetic wave transmission or blocking performance required for design while using the metal layer as it is without processing it. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of a window material according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the metasurface film according to the first embodiment. [Figure 3] Fig. 3(A) is a plan view of the metasurface film according to the first embodiment, and Fig. 3(B) is an enlarged view of part A in Fig. 3(A). [Figure 4] Fig. 4(A) shows a modified example of the metal pattern, and Fig. 4(B) shows another modified example of the metal pattern. [Figure 5]5A is a plan view of the metasurface film according to the second embodiment. FIG. 5B is an enlarged view of part B in FIG. 4A. FIG. 5C is a cross-sectional view. [Figure 6] FIG. 6 is a cross-sectional view of a metasurface film according to the first modified example. [Figure 7] FIG. 7 is a cross-sectional view of a metasurface film according to the second modified example. [Figure 8] FIG. 8 is a schematic diagram of a waveguide model used in the examples. [Figure 9] FIG. 9 is a schematic diagram of the metasurface sheet used in the examples. [Figure 10] Fig. 10(A) is a graph showing the results of a numerical simulation, and Fig. 10(B) is an enlarged view of the region in Fig. 10(A) where the difference is 0 dB or more. [Figure 11] Fig. 11(A) is a graph showing the results of a numerical simulation, and Fig. 11(B) is an enlarged view of the region in Fig. 11(A) where the difference is 0 dB or more. DETAILED DESCRIPTION OF THE INVENTION

[0017] First Embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. A laminated structure 10 according to the first embodiment includes a laminate 1 in which a plate material 2 and a metal layer 3 are stacked, and a metasurface sheet 4 attached to the laminate 1. The laminated structure 10 is configured so that the intensity of an output wave relative to an input wave is stronger for electromagnetic waves of a predetermined frequency (referred to as the "first frequency") or less than for electromagnetic waves exceeding the first frequency. The laminated structure 10 according to this embodiment forms a low-pass filter with the first frequency as its cutoff frequency.

[0018] On the other hand, the metasurface sheet 4 attached to the laminate 1 is configured so that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves of a predetermined frequency (referred to as the "second frequency") or higher than for electromagnetic waves below the second frequency. The metasurface sheet 4 according to this embodiment constitutes a high-pass filter with the second frequency as its cutoff frequency.

[0019] Thus, according to the laminated structure 10 of this embodiment, by combining the metal layer 3 and the metasurface sheet 4, the function of the metasurface sheet 4 as a high-pass filter can be made to function as a low-pass filter. Therefore, according to the laminated structure 10 of this embodiment, the electromagnetic wave transmission performance or blocking performance required for the design can be obtained even while using the metal layer 3 as is without processing it. As a result, since there is no need to process the metal layer 3 in the laminated structure 10, the electromagnetic wave transmission performance or blocking performance can be obtained with good manufacturability.

[0020] In this specification, the term "sheet" refers to a thin material whose thickness is 10% or less of the maximum length between the outer edges in a planar view and which has a large expanse. When the shape in a planar view is rectangular, the "maximum length between the outer edges in a planar view" refers to the length of the diagonal. When the shape in a planar view is circular, the "maximum length between the outer edges in a planar view" refers to the length of the diameter. In this specification, membranes, foils, films, etc. are also included in the term "sheet."

[0021] In the laminated structure 10, the specific frequency band of the incident wave is preferably any radio wave in the range of 0.5 GHz to 60 GHz. In this embodiment, the incident wave is set to belong to the 5G frequency band (3 GHz to 5 GHz, 25 GHz to 30 GHz). However, in the laminated structure 10, there is no particular restriction on the frequency band of the incident wave. The frequency band of the incident wave can be set to a desired frequency band by changing the shape, size, and / or spacing of the resonating portions 411 in the metasurface sheet 4.

[0022] Each element of the laminated structure 10 and metasurface sheet 4 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°.

[0023] [Laminated structure 10] The laminated structure 10 is a structure including a metasurface sheet 4. Examples of the laminated structure 10 include window glass, walls, ceilings, floors, partitions, smoke barriers, furniture, balcony railings, parapets, blinds, storm shutters, shutters, and doors. In this embodiment, the laminated structure 10 is a window structure for a building. The window structure includes a window material as the laminate 1 and a metasurface sheet 4.

[0024] As described above, the laminated structure 10 is configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves of a first frequency or less than the first frequency than for electromagnetic waves exceeding the first frequency. The first frequency that serves as the cutoff frequency is not particularly limited, but is preferably in the range of 3.0 GHz or more and 4.0 GHz or less, more preferably in the range of 3.2 GHz or more and 3.8 GHz or less, and even more preferably in the range of 3.3 GHz or more and 3.7 GHz or less.

[0025] [Window materials] The laminate 1 is a member in which at least one plate material and a metal layer are laminated. In this embodiment, the laminate 1 is a window material. The window material is a double-pane glass having a plurality of transparent plates 20 as at least one plate material 2. However, the window material may also be a single-pane glass. As shown in FIG. 1 , the window material includes a plurality of transparent plates 20, a metal layer 3, and a spacer 5 that maintains a distance between the plurality of transparent plates 20.

[0026] (Transparent plate 20) The transparent plate 20 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 20 is not limited to being colorless and transparent, and may be colored.

[0027] The transparent plate 20 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, the transparent plate 20 may also be made of an acrylic plate, a polycarbonate plate, or the like.

[0028] There are no particular limitations on the shape of the transparent plate 20. The shape of the transparent plate 20 may be, for example, a rectangular shape in a plan view, a circular shape in a plan view, a pentagonal shape in a plan view, a hexagonal shape in a plan view, an elliptical shape in a plan view, etc. Here, "plan view" means that the main surface of the transparent plate 20 is viewed from a direction perpendicular to the main surface.

[0029] 1, the multiple transparent plates 20 are arranged at regular intervals in the thickness direction of the laminate 1. Of the adjacent transparent plates 20, one transparent plate 20 may be referred to as a "first transparent plate 201" and the other transparent plate 20 may be referred to as a "second transparent plate 202."

[0030] A spacer 5 is disposed between the first transparent plate 201 and the second transparent plate 202. The spacer 5 maintains the distance between the two adjacent transparent plates 201, 22. The outer peripheries of the multiple transparent plates 20 are surrounded by a sealing material (not shown), and the space (heat insulating layer 6) between the two adjacent transparent plates 201, 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.

[0031] The first transparent plate 201 has a first surface 211 and a second surface 212. Similarly, the second transparent plate 202 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 20. The second surfaces 212, 222 are main surfaces on the opposite side to the first surfaces 211, 221. In this embodiment, the first surfaces 211, 221 refer to surfaces of adjacent transparent plates 20 that face each other (inner surfaces in the thickness direction of the window material), and the second surfaces 212, 222 refer to outer surfaces of the window material.

[0032] The laminate 1 of this embodiment is a double glazing consisting of two transparent plates 20, but it may also be a triple glazing consisting of three transparent plates 20, or may be composed of four or more transparent plates 20.

[0033] (metal layer 3) The metal layer 3 is laminated on a plate material (transparent plate 20) to improve the heat insulating properties of the window material. 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.

[0034] The metal layer 3 may be laminated on any one of the plurality of transparent plates 20. In this embodiment, the metal layer 3 is laminated on the first surface 211 of the first transparent plate 201. The metal layer 3 is laminated over the entire surface of the first surface 211 of the transparent plate 20. The metal layer 3 is laminated on the transparent plate 20 by, for example, coating, vapor deposition, adhesion, welding, or the like.

[0035] (window frame) A window frame (not shown) surrounds the periphery of the window material. It is preferable that the window material be 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 fitted into the opening, and a movable frame that is movable relative to the fixed frame and into which the window material 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.

[0036] 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.

[0037] Examples of the window structure 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 according to this embodiment can be applied to windows for automobiles, aircraft, ships, trains, ropeways, etc. in addition to buildings.

[0038] [Metasurface Sheet 4] The metasurface sheet 4 is provided on the laminate 1. The metasurface sheet 4 according to this embodiment is a metasurface sheet 4 attached to the first transparent plate 201 of the window material. However, the metasurface sheet 4 may also be attached to the second transparent plate 202 or the metal layer 3.

[0039] 2 and 3, the metasurface sheet 4 comprises, in this order, a substrate 42 attached to the transparent plate 20 or the metal layer 3, a metal pattern 41 formed on the substrate 42, and a protective film 44. By attaching the metasurface sheet 4 to the transparent plate 20 or the metal layer 3, the laminated structure 10 can achieve a performance in which electromagnetic waves below a first frequency are stronger than electromagnetic waves above the first frequency.

[0040] The metasurface sheet 4 according to this embodiment may cover the entire surface of the plate material 2, or may be attached to only a part of the entire surface.

[0041] The metasurface sheet 4 according to this embodiment is itself a high-pass filter configured so that the intensity (power) of the outgoing wave relative to the incident wave is stronger for electromagnetic waves of a second frequency or higher than for electromagnetic waves of a second frequency or lower. Note that the outgoing wave emitted from the metasurface sheet 4 may propagate in the same direction as the incident wave relative to the metasurface sheet 4 (i.e., the incident wave is reflected by the metasurface sheet 4), or may propagate in the opposite direction to the incident wave (i.e., the incident wave passes through the metasurface sheet 4).

[0042] The second frequency that is the cutoff frequency is not particularly limited, but is preferably in the range of 3.2 GHz or more and 4.2 GHz or less, more preferably in the range of 3.4 GHz or more and 4.0 GHz or less, and even more preferably in the range of 3.5 GHz or more and 3.9 GHz or less.

[0043] (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 20 or the metal layer 3. An adhesive layer (hereinafter referred to as the first adhesive layer 45) is preferably 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 the capsules rupture when pressure is applied from the substrate 42 toward the transparent plate 20 or the metal layer 3 during bonding, thereby enabling bonding. However, the first adhesive layer 45 may 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.

[0044] 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.

[0045] The base material 42 may be, for example, a synthetic resin, FRP (Fiber Reinforced Plastics), or a cardboard. Examples of synthetic resins include 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.

[0046] 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.

[0047] 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.

[0048] (Metal pattern 41) The metal pattern 41 is a metal microstructure portion having a structure smaller than the wavelength of the target electromagnetic wave (for example, 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, the metal pattern A periodically formed figure in the turn 41 may be referred to as a "resonating portion 411."

[0049] The metal pattern 41 has a conductor (hereinafter also referred to as a "conductor region 412"). 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.

[0050] 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.

[0051] 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.

[0052] The shape of each resonator portion 411 of the metal pattern 41 may take various shapes depending on the frequency band of the incident wave, 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 411 in the metal pattern 41 according to this embodiment, it is possible to obtain the transmission or blocking performance of electromagnetic waves in a desired frequency band.

[0053] 3(A) and 3(B), each resonator 411 has a conductor region 412, which is a region made of a conductor, and a conductor-free region 413, which is a region where no conductor is provided. The resonator 411 is repeatedly formed in the vertical direction (X direction in the figure) and the horizontal direction (Y direction in the figure), that is, formed periodically.

[0054] The conductor region 412 includes an outer edge 414 of the resonator 411. The outer edge 414 of the resonator 411 is a boundary between adjacent resonators 411 and may be a virtual outer edge. In this embodiment, the outer edge 414 of the resonator 411 is located at the center in the width direction of the linear body 415 that surrounds the conductor-free region 413.

[0055] The conductor region 412 preferably has a continuous shape without any breaks in the circumferential direction. Examples of the conductor region 412 include a rectangular frame shape, a triangular frame shape, a pentagonal frame shape, a hexagonal frame shape, and a circular frame shape. The conductor region 412 according to this embodiment is a rectangular frame-shaped region. As a result, when viewed as a metal pattern, it is formed in a lattice shape, as shown in FIG. 3(A).

[0056] The conductor region 412 is preferably formed with rotational symmetry around the center of gravity of the resonator unit 411. This reduces the dependency on the angle of the incident wave in a plan view. The conductor region 412 according to this embodiment is square-shaped, and therefore has a four-fold symmetry. However, the conductor region 412 may have two-fold symmetry, three-fold symmetry, or five-fold or more rotational symmetry.

[0057] The length D1 of one side of the conductor-free region 413 is preferably 1 / 10 of the wavelength of the desired frequency band. To give some examples, when the frequency of the incident wave is 3 GHz, the length D1 of one side is 10 mm. When the frequency of the incident wave is 4.7 GHz, the length D1 of one side is 6.3 mm. When the frequency of the incident wave is 4.9 GHz, the length D1 of one side is 10 mm. The length of the side D1 is 6.1 mm. When the frequency of the incident wave is 7 GHz, the length of one side is The length D1 is 4.3 mm. However, the propagation speed of electromagnetic waves is 299,792,458 m / s. The "length of one side" in this specification is the length in millimeters, rounded to one decimal place.

[0058] When the non-conductor region 413 is a rectangular region, the longer of the vertical length and the horizontal length is preferably 1 / 10 of the wavelength of the frequency of the incident wave. Furthermore, when the non-conductor region 413 is a circular region, the diameter is preferably 1 / 10 of the wavelength of the frequency of the incident wave. Furthermore, when the non-conductor region 413 is a polygon with five or more sides, the length of the longest diagonal line among the multiple diagonals is preferably 1 / 10 of the wavelength of a predetermined frequency. This configuration allows transmission or blocking performance to be achieved for incident waves in a desired frequency band.

[0059] The width (line width W1) of the linear bodies 415 surrounding the conductor-free region 413 is preferably the same in the longitudinal direction (same width). The line width W1 is preferably, for example, 10 μm or more, more preferably 1 mm or more, and even more preferably 1.8 mm or more. On the other hand, the line width W1 is preferably 2 mm or less. When the line width of the linear bodies 415 is 2 mm or less, the degree of freedom in designing the metal pattern 41 can be improved. When the line width of the linear bodies 415 is 10 μm or more, the productivity of the metal pattern can be maintained while keeping costs down.

[0060] However, the conductor region 412 is not limited to a combination of linear bodies 415. The conductor region 412 may be formed in a region such as a perforated metal, as shown in Fig. 4(A), for example. Alternatively, the conductor region 412 may be formed in a region of a perforated metal where each hole is triangular or polygonal, as shown in Fig. 4(B).

[0061] The non-conductor region 413 is a region where no conductor is formed, and is surrounded by the conductor region 412 in each resonator 411. Examples of the non-conductor region 413 include a circular shape, a triangular shape, a rectangular shape, a pentagonal shape, and a hexagonal shape.

[0062] The metal pattern 41 having such a configuration preferably has a relative dielectric constant of at least 7. On the other hand, the upper limit of the relative dielectric constant is preferably 10,000 or less.

[0063] (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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Second Embodiment Next, a second embodiment will be described. The laminated structure 10 according to the second embodiment is the same as the first embodiment in that it includes a laminate 1 in which plate materials and metal layers are stacked, and a metasurface sheet 4 attached to the laminate 1. However, in this embodiment, the laminated structure 10 is configured so that the intensity of the output wave relative to the incident wave is stronger for electromagnetic waves of a predetermined frequency (referred to as the "third frequency") or higher than for electromagnetic waves below that frequency. In other words, the laminated structure 10 according to the second embodiment differs from the laminated structure 10 according to the first embodiment in that it constitutes a high-pass filter with the third frequency as its cutoff frequency.

[0068] The third frequency, which is the cutoff frequency, is not particularly limited, but is preferably in the range of 4.0 GHz or more and 5.0 GHz or less, more preferably in the range of 4.2 GHz or more and 4.8 GHz or less, and even more preferably in the range of 4.3 GHz or more and 4.7 GHz or less.

[0069] On the other hand, the metasurface sheet 4 attached to the laminate 1 is configured so that the intensity of the outgoing wave relative to the incident wave is stronger for electromagnetic waves of a predetermined frequency (referred to as the "fourth frequency") or less than that for electromagnetic waves exceeding the fourth frequency. The metasurface sheet 4 according to this embodiment constitutes a low-pass filter with the fourth frequency as its cutoff frequency.

[0070] The fourth frequency, which is the cutoff frequency of the metasurface sheet 4 in this embodiment, is not particularly limited, but is preferably in the range of 4.2 GHz or more and 5.2 GHz or less, more preferably in the range of 4.4 GHz or more and 5.0 GHz or less, and even more preferably in the range of 4.5 GHz or more and 4.9 GHz or less.

[0071] In this way, the laminated structure 10 according to the second embodiment can make the low-pass filter function of the metasurface sheet 4 function as a high-pass filter. Therefore, the laminated structure 10 according to this embodiment can obtain the electromagnetic wave transmission or blocking performance required for design, even when using the metal layer as is without processing it.

[0072] In this embodiment, the laminate 1 having the plate material and the metal layer has the same structure as in the first embodiment, and only the metal pattern of the metasurface sheet 4 is different. Here, we will mainly explain the configuration that differs from the first embodiment, and omit explanations of the configuration that is the same as in the first embodiment.

[0073] The metal pattern of the metasurface sheet 4 is a complex, periodically formed metal pattern as shown in Figure 5. 5, each of the resonating portions 411 has a conductor region 412 that is a region made of a conductor, and a conductor-free region 413 that is a region where no conductor is provided.

[0074] Conductor region 412 is preferably a rectangular region made of a conductor. Conductor region 412 according to this embodiment is a square region. The length D2 of one side of conductor region 412 is preferably 1 / 10 of the wavelength of the frequency band of the incident wave. However, conductor region 412 may also be, for example, triangular, pentagonal, hexagonal, circular, or other shapes.

[0075] As in the first embodiment, the conductor region 412 is preferably formed in rotational symmetry around the center of gravity of the resonator unit 411. This reduces the dependency on the angle of the incident wave in a plan view.

[0076] The conductor-free region 413 partitions the conductor region 412. The conductor-free region 413 according to this embodiment is surrounded by four straight line portions 416. The outer edge 414 of one resonator portion 411 is located at the center of the straight line portion 416 in the width direction, as shown by the imaginary line in FIG. 5(B). Therefore, the conductor-free region 413 in the metal pattern is formed in a lattice pattern, as shown in FIG. 5.

[0077] It is preferable that the width W2 of all of the straight line portions 416 of the conductor-free region 413 be the same in the longitudinal direction. The width W2 of the straight line portions 416 is, for example, preferably 10 μm or more, more preferably 1 mm or more, and even more preferably 1.8 mm or more. On the other hand, the width W2 of the straight line portions 416 is preferably 2 mm or less. However, in the present invention, the conductor-free region 413 is not limited to being linear.

[0078] <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.

[0079] (First Modification) In the first and second embodiments, the laminate 1 has multiple transparent plates 20, but as shown in FIG. 5, the laminate 1 may have only one transparent plate 20. As shown in FIG. 5, a metal layer 3 is laminated on a first surface 211 of the transparent plate 20. A metasurface sheet 4 is attached to the metal layer 3. The metasurface sheet 4 may also be provided on a second surface 212 on which the metal layer 3 is not provided.

[0080] 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 20, for example, after the window material is installed in the window frame.

[0081] (Second Modification) In the first and second embodiments, the metasurface sheet 4 is attached to a transparent plate 20 (first transparent plate 201) on which a metal layer 3 is laminated, but as shown in Figure 6, it may also be attached to a transparent plate 20 (second transparent plate 202) other than the transparent plate 20 on which the metal layer 3 is laminated.

[0082] The distance between the metasurface sheet 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 sheet 4 and the metal layer 3 may be 0 mm. That is, the metasurface sheet 4 may be directly bonded to the metal layer 3 (see Figure 4).

[0083] (Other variations) In the first and second embodiments, examples have been described in which a transparent plate 20 is used as the plate material 2, but in the present invention, the plate material 2 does not have to be transparent. Examples of opaque plate materials 2 include wood boards, MDF, steel plates, aluminum plates, mud walls, FRP, engineering plastics, and carbon.

[0084] <Example> In this example, we used numerical simulation to confirm the extent to which placing the metasurface sheet 4 on the surface of a plate changes the radio wave transmission or blocking performance compared to using only the metasurface sheet 4.

[0085] The numerical simulation was performed based on the waveguide model 9 shown in Fig. 6. In the radio wave transmitting body included in the illustrated waveguide model 9, the conductive layer pattern (i.e., the conditions of the meta-structure) shown in Fig. 7 was specified, and in this specified waveguide model 9, the radio wave intensity transmitted through the window material was calculated.

[0086] The dimensions PA and GAP shown in Figure 7 are defined as variables that define the pattern of the conductive layer of the metasurface sheet 4. In the metasurface sheet 4 that functions as a high-pass filter, the dimension PA is the length of one side of the non-conductor region 413, and the dimension GAP refers to the width of the conductor region 412. In the metasurface sheet 4 that functions as a low-pass filter, the dimension PA is the length of one side of the conductor region 412, and the dimension GAP refers to the width of the non-conductor region 413.

[0087] The radio wave intensity transmitted through the plate material was calculated by comprehensively combining multiple conditions (numerical ranges) shown in Table 1 and comprehensively changing the specified dimensions PA and GAP within the numerical ranges shown in Table 1. In this example, there were 11 different dimensions PA and 15 different dimensions GAP, for a total of 165 different conditions, and the radio wave intensity (dB) transmitted through the plate material and metasurface sheet 4 was calculated for radio waves whose incident wave was changed from 1 GHz to 10 GHz. The value calculated by multiplying the radio wave intensity transmitted through the plate material (Low-E film) by -60.9578 dB (minus 60.9578 dB) was used as the intensity of the incident radio wave.

[0088] [Table 1] The results of the numerical simulation are shown in Figures 8 and 9. Figure 8 shows the results when a metasurface sheet 4 with a high-pass filter function is used. Figure 8(B) is an enlarged view of the region in Figure 8(A) where the difference (dB) is ≧0. Figure 9 shows the results when a metasurface sheet 4 with a low-pass filter function is used. Figure 9(B) is an enlarged view of the region in Figure 9(A) where the difference (dB) is ≧0.

[0089] As can be seen from Figure 8, the laminated structure 10 using the metasurface sheet 4 with the function of a high-pass filter has the function of a low-pass filter with a cutoff frequency of about 7 GHz. This confirms that by combining the metasurface sheet 4 with the function of a high-pass filter with the metal layer 3, it is possible to obtain the laminated structure 10 with the function of a low-pass filter.

[0090] 9, the laminated structure 10 using the metasurface sheet 4 with the function of a low-pass filter also functions as a high-pass filter with a cutoff frequency of about 5 GHz. This confirms that by combining the metasurface sheet 4 with the function of a low-pass filter with the metal layer 3, it is possible to obtain the laminated structure 10 with the function of a high-pass filter. [Explanation of symbols]

[0091] 10. Laminated structure 1. Laminate 2 Board material 3 metal layer 4 Metasurface Sheet 41 Metal Pattern 411 Resonance part 412 Conductor Area 413 Non-conductor region 42 Base material

Claims

1. A laminated structure configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves having a frequency equal to or lower than a predetermined frequency than for electromagnetic waves having a frequency higher than the predetermined frequency, a laminate including at least one plate material and a metal layer laminated on the at least one plate material; A metasurface sheet attached to the laminate; Equipped with The metasurface sheet is configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves having a frequency equal to or higher than a predetermined frequency than for electromagnetic waves having a frequency lower than a predetermined frequency. Laminated structure.

2. The metasurface sheet is A substrate; a metal pattern formed on the substrate, the metal pattern having a plurality of resonating units periodically formed thereon; and Each of the plurality of resonating units is a conductor region including an outer edge of the resonator portion; a conductor-free region that is a region on the inside of the outer edge where no conductor is provided, The laminated structure according to claim 1 .

3. The conductor region is composed of a plurality of linear bodies surrounding the non-conductor region. The laminated structure according to claim 2 .

4. Each of the resonator parts is formed in a rectangular shape, so that the conductor of the metal pattern is formed in a lattice shape. The laminated structure according to claim 3 .

5. A laminated structure configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves having a predetermined frequency or higher than that of electromagnetic waves having a frequency lower than the predetermined frequency, a laminate including at least one plate material and a metal layer laminated on the at least one plate material; A metasurface sheet attached to the laminate; Equipped with The metasurface sheet is configured so that the intensity of an outgoing wave relative to an incident wave is stronger for electromagnetic waves having a frequency equal to or lower than a predetermined frequency than for electromagnetic waves having a frequency higher than a predetermined frequency. Laminated structure.

6. The metasurface sheet is A substrate; a metal pattern formed on the substrate, the metal pattern having a plurality of resonating units periodically formed thereon; and The metal pattern is A plurality of conductor regions made of conductors are separated by conductor-free regions where no conductors are provided. The laminated structure according to claim 1 .

7. the non-conductor-forming region is in a lattice pattern; The laminated structure according to claim 6 .

8. the plate is a window glass, the metal layer is a Low-E film; The laminate structure according to any one of claims 1 to 7.

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