Radio wave permeable materials and window materials

Abstract

Easily improve the radio wave transmission properties of window materials. [Solution] A translucent radio wave permeator 4 is disposed on the surface of a window material 1 comprising at least one transparent plate 2 and a metal layer 3 laminated on at least one transparent plate 2, and comprises a conductive layer 41 and a base layer 43 supporting the conductive layer 41, wherein the conductive layer 41 is arranged periodically in multiple vertical and horizontal directions in a pattern having conductive regions 41 and non-conductive regions 42, and a current I flows through the conductive layer 41 when radio waves are incident on it. 41 A radio wave permeable material 4 whose orientation is opposite to the direction of the current I3 flowing through the metal layer 3 due to the incidence of radio waves.

Description

Technical Field

[0001] The present invention relates to a radio wave transmission body disposed on the surface of a window material and a window material provided with the radio wave transmission body.

Background Art

[0002] In recent years, as energy-saving measures for buildings, the spread of window glass (hereinafter referred to as window material) with excellent heat insulation in summer and heat insulation in winter has been progressing. In such a window material, a Low-E film is formed on the entire surface of a certain surface constituting the window material.

[0003] On the other hand, it is known that when a Low-E film is formed on a window material, the radio wave permeability decreases over a wide frequency band. The occurrence of a radio wave dead zone indoors in a building is a problem. Therefore, in conventional window materials, for example, as in Patent Document 1, a radio wave transmission region is formed by removing a part of the Low-E film by laser processing to improve the indoor radio wave communication environment.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when manufacturing a window material, performing an operation of removing a part of the Low-E film as in Patent Document 1 cannot be said to have good productivity. In addition, it is not practical to perform such a Low-E film removal process on a window material that has already been installed in a building. There is a need for a technology to easily improve the radio wave permeability of window materials.

[0006] The present invention provides a technology for easily improving the radio wave permeability of window materials.

Means for Solving the Problems

[0007] To achieve the above objectives, the present invention encompasses the subject matter described in the following sections. (Section 1) A light-transmitting radio wave conductor is disposed on the surface of a window material comprising at least one transparent plate and a metal layer laminated on the at least one transparent plate. A conductive layer, A substrate layer supporting the conductive layer, Equipped with, The conductive layer has a pattern having conductive regions and non-conductive regions, and multiple layers are arranged periodically in the vertical and horizontal directions. A radio wave transparent material in which the direction of the current flowing through the conductive layer when radio waves are incident on it is opposite to the direction of the current flowing through the metal layer when radio waves are incident on it. (Section 2) The radio wave transparent material according to item 1, wherein the angle (boundary angle) between the direction of the current flowing through the conductive layer and the direction of the current flowing through the metal layer is within the range of 125° to 180°. (Section 3) The radio wave transparent body according to item 1 or 2, wherein the conductive layer has a pattern in which conductive regions and non-conductive regions surrounding the conductive regions are arranged periodically in the vertical and horizontal directions. (Section 4) The radio wave transparent body according to item 1 or 2, wherein the conductive layer has a pattern in which a first conductive region, a non-conductive region surrounding the first conductive region, and a second conductive region surrounding the non-conductive region are arranged periodically in the vertical and horizontal directions. (Section 5) The radio wave transparent body according to item 1 or 2, wherein the conductive layer has a pattern in which a first nonconductive region, a conductive region surrounding the first nonconductive region, and a second nonconductive region surrounding the conductive region are arranged periodically in the vertical and horizontal directions. (Section 6) At least one transparent plate, A metal layer laminated on at least one of the transparent plates, A radio wave transparent material according to any one of items 1 to 5, attached to the transparent plate or the metal layer, Window material equipped with [a specific feature / feature]. [Effects of the Invention]

[0008] According to the present invention, the radio wave transmissivity of the window material can be easily increased.

Brief Description of the Drawings

[0009] [Figure 1] It is a cross-sectional view of a window material according to an embodiment. [Figure 2] It is a diagram showing the overall schematic configuration of a radio wave transmission body according to an embodiment. (A) is a plan view, and (B) is an enlarged view of part A in (A). [Figure 3] It is a cross-sectional view of a radio wave transmission body according to an embodiment. [Figure 4] It is a schematic cross-sectional view of a window material for explaining the direction of the current flowing through the conductive layer of the radio wave transmission body and the direction of the current flowing through the metal layer provided in the window material. [Figure 5] It is a diagram for explaining another example of the pattern of the conductive layer provided in the radio wave transmission body. [Figure 6] It is a diagram for explaining another example of the pattern of the conductive layer provided in the radio wave transmission body. [Figure 7] It is a cross-sectional view of a window material according to Modification 1. [Figure 8] It is a cross-sectional view of a window material according to Modification 2. [Figure 9] It is a waveguide model used in the numerical simulation according to an example. [Figure 10] It is a diagram for explaining the result of a numerical simulation regarding the pattern of the conductive layer functioning as a band-pass filter. (A) is a diagram showing the planar structure of the conductive layer used in the numerical simulation. (B) is a graph showing the result of the numerical simulation regarding the radio wave transmissivity of the radio wave transmission body. [Figure 11] It is a diagram for explaining the result of a numerical simulation regarding the pattern of the conductive layer functioning as a band-pass filter. (A) is a diagram showing the direction of the current flowing through the conductive layer. (B) is a diagram showing the direction of the current flowing through the metal layer (Low-E film) provided in the window material. [Figure 12] FIG. is for explaining the result of numerical simulation regarding the pattern of the conductive layer functioning as a band-stop filter. (A) is a diagram showing the planar structure of the conductive layer used for the numerical simulation. (B) is a graph showing the result of the numerical simulation regarding the radio wave transmissivity of the radio wave transmission body. [Figure 13] FIG. is for explaining the result of numerical simulation regarding the pattern of the conductive layer functioning as a band-stop filter. (A) is a diagram showing the direction of the current flowing through the conductive layer. (B) is a diagram showing the direction of the current flowing through the metal layer (Low-E film) provided in the window material. [Figure 14] FIG. is for explaining the result of numerical simulation regarding the pattern of the conductive layer functioning as a low-pass filter. (A) is a diagram showing the planar structure of the conductive layer used for the numerical simulation. (B) is a graph showing the result of the numerical simulation regarding the radio wave transmissivity of the radio wave transmission body. [Figure 15] FIG. is for explaining the result of numerical simulation regarding the pattern of the conductive layer functioning as a low-pass filter. (A) is a diagram showing the direction of the current flowing through the conductive layer. (B) is a diagram showing the direction of the current flowing through the metal layer (Low-E film) provided in the window material.

MODE FOR CARRYING OUT THE INVENTION

[0010] <EMBODIMENT> Hereinafter, embodiments of the present invention will be described with reference to the drawings. Refer to FIG. 1. In the window material 1 according to the present embodiment, a translucent radio wave transmission body 4 is disposed on the surface. The window material 1 according to the present embodiment includes a metal layer 3, and thus the radio wave transmissivity is reduced over a wide frequency band. However, since the radio wave transmission body 4 which is a metasurface film is disposed on the surface, the radio wave transmissivity is improved.

[0011] Refer to Figures 2 to 4. Figure 4 is a schematic cross-sectional view of the window material to illustrate the direction of current flowing through the conductive layer of the radio wave permeable and the direction of current flowing through the metal layer provided in the window material. For the sake of clarity, some components of the window material 1 and radio wave permeable 4 are not shown. For window material 1, the spacer 5, intermediate layer 6, and second transparent plate 22 are not shown. For radio wave permeable 4, the adhesive layers 44, 46, and protective film 45 are not shown. The thickness of some layers is exaggerated in the illustration.

[0012] The radio wave permeable body 4 comprises a conductive layer 41 and a substrate layer 43 that supports the conductive layer 41. The conductive layer 41 has a pattern having conductive regions 41 and non-conductive regions 42, and multiple layers are arranged periodically in the vertical and horizontal directions, and a current I flows through the conductive layer 41 when radio waves are incident on it. 41 The direction of the current is opposite to the direction of the current I3 flowing through the metal layer 3 due to the incidence of radio waves. In this way, the inventors have found that in a translucent radio wave transparent material 4, the current I3 flowing through the conductive layer 41 of the radio wave transparent material 4 41 We found that the radio wave transmittance of the window material 1 is increased when multiple conductive layers 41, each having a conductive region 41 and a non-conductive region 42, are arranged periodically in the vertical and horizontal directions such that the direction of the current I3 flowing through the metal layer 3 provided in the window material 1 is approximately opposite to the direction of the current I3 flowing through the metal layer 3 provided in the window material 1. The direction of the two currents being approximately opposite means that in a plan view, the current I 41 The angle (boundary angle) between the direction of the element and the direction of the current I3 is preferably in the range of 91° to 180°, and more preferably in the range of 125° to 180°.

[0013] First, we will describe the window material 1 on which the radio wave permeable material 4 is placed. Next, we will describe the various components of the window material 1, including the radio wave permeable material 4.

[0014] (Window materials) As shown in Figure 1, the window material 1 is a double-glazed window having multiple transparent plates 2. The window material 1 comprises multiple transparent plates 2, a metal layer 3, and a radio wave transparent material 4. The window material 1 also includes spacers 5 that maintain the distance between the multiple transparent plates 2.

[0015] As shown in Figures 2 and 3, the radio wave transparent body 4 comprises a base layer 43 attached to a transparent plate 2 or a metal layer 3, and a conductive layer 41 formed on the base layer 43.

[0016] The window material 1 according to this embodiment, with this configuration, can enhance radio wave transparency only for radio waves in a specific frequency band, even though the metal layer 3 reflects or blocks radio waves. Moreover, since it only requires attaching the radio wave permeable material 4 to the existing window material 1 with the metal layer 3 laminated on it, the window material 1 can be manufactured with high manufacturability.

[0017] The window material 1 according to this embodiment can be used, for example, as window glass in buildings, as well as for skylights in doors, fixed windows in ceilings, floors, etc. Furthermore, the window material 1 according to this embodiment can be used not only in buildings, but also in windows of automobiles, aircraft, ships, trains, ropeways, etc.

[0018] In the window material 1, the specific frequency band of radio waves that can enhance radio wave transparency is preferably any radio wave belonging to the range of 0.5 GHz to 60 GHz. In this embodiment, the transparent plate 2 is set to have high radio wave transparency in the 5G frequency band (3 GHz to 5 GHz, 25 GHz to 30 GHz). However, there are no particular restrictions on the frequency band in which the radio wave transparency is to be enhanced in the window material 1. The specific frequency band in which the radio wave transparency is to be enhanced can be set to the desired frequency band by changing the shape of the conductive layer 41 in the radio wave transparent body 4.

[0019] (Transparent plate 2) Transparent plate 2 is a transparent plate material. In this specification, "transparent" means that the light transmittance is 10% or more of the peak wavelength of the light before incidence, preferably 50% or more, and more preferably 80% or more. In other words, "semi-transparent," where the light transmittance is, for example, about 30% of the peak wavelength of the light before incidence, is also included in "transparent" as defined in this specification. Furthermore, transparent plate 2 is not limited to being colorless and transparent, but may be colored.

[0020] In this embodiment, the transparent plate 2 is preferably a glass plate. Examples of glass plates include float glass, patterned glass, frosted glass, wired glass, and tempered glass. However, in addition to glass plates, the transparent plate 2 may also be an acrylic plate, a polycarbonate plate, or the like.

[0021] There are no particular restrictions on the shape of the transparent plate 2. The shape of the transparent plate 2 may be, for example, rectangular, circular, pentagonal, hexagonal, or elliptical in plan view. Here, "plan view" means viewing the main surface of the transparent plate 2 from a direction perpendicular to that main surface.

[0022] As shown in Figure 1, the multiple transparent plates 2 are arranged at regular intervals in the thickness direction of the window material 1. Of the adjacent transparent plates 2, one transparent plate 2 is sometimes referred to as the "first transparent plate 21" and the other transparent plate 2 as the "second transparent plate 22".

[0023] A spacer 5 is placed 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 and 22. The outer periphery of the multiple transparent plates 2 is surrounded by a sealing material (not shown), and the space (intermediate layer 6) between the two adjacent transparent plates 21 and 22 is formed in an airtight manner. Preferably, the intermediate layer 6 is filled with an insulating gas. Examples of insulating gases include inert gases such as argon gas. However, the intermediate layer 6 may be filled with air. The intermediate layer 6 may also be a vacuum.

[0024] 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 and 221 are one of the surfaces (main surfaces) in the thickness direction of the transparent plate 2. The second surfaces 212 and 222 are main surfaces opposite to the first surfaces 211 and 221. In this embodiment, the first surfaces 211 and 221 refer to surfaces that face each other in adjacent transparent plates 2 (inner surfaces in the thickness direction of the window material 1), and the second surfaces 212 and 222 refer to outer surfaces of the window material 1.

[0025] In this embodiment, the window material 1 is a double-glazed glass consisting of two transparent plates 2, but it may also be a triple-glazed glass consisting of three transparent plates 2, or it may be composed of four or more transparent plates 2.

[0026] (metal layer 3) The metal layer 3 is laminated on the transparent plate 2 to improve the heat insulation 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, but examples include a film in which a transparent dielectric layer, an infrared reflective layer, and another transparent dielectric layer are laminated in that 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) and semiconductor films.

[0027] The metal layer 3 can be laminated onto any of the multiple transparent plates 2. In this embodiment, it is laminated onto the first surface 211 of the first transparent plate 21. The metal layer 3 is laminated across the entire surface of the first surface 211 of the transparent plate 2. The metal layer 3 is laminated onto the transparent plate 2 by, for example, coating, vapor deposition, adhesion, welding, etc.

[0028] (Radio wave transparent body 4) The radio wave permeable material 4 is attached to the transparent plate 2 or the metal layer 3. By attaching the radio wave permeable material 4 to the transparent plate 2 or the metal layer 3, the radio wave transparency of the window material 1 can be increased in a specific frequency band of radio waves. As shown in Figures 2 and 3, the radio wave permeable material 4 is laminated in the following order: a base layer 43, a conductive layer 41, and a protective film 45. In this embodiment, the radio wave permeable material 4 is attached to the second surface 212 of the first transparent plate 21. The radio wave permeable material 4 may cover the entire surface of the transparent plate 2, or it may be attached to only a part of the entire surface.

[0029] (Base material layer 43) The base layer 43 supports the conductive layer 41. In this embodiment, the base layer 43 is transparent. The base layer 43 is attached to the transparent plate 2 or the metal layer 3. On the surface of the base layer 43 opposite to the conductive layer 41, an adhesive layer (hereinafter referred to as the first adhesive layer 46) is provided. The first adhesive layer 46 preferably has a structure in which, before bonding, it has a number of capsules filled with adhesive, and when pressure is applied from the base layer 43 toward the transparent plate 2 or the metal layer 3 during bonding, the capsules burst and bonding is possible. However, the first adhesive layer 46 may be an adhesive that is applied without being filled into capsules. Examples of adhesives include synthetic resins such as acrylic resin, silicone resin, and polyvinyl alcohol resin.

[0030] As shown in Figure 2, the outer shape of the base layer 43 in this embodiment is rectangular (more specifically, square) in plan view. However, there are no particular restrictions on the shape of the base layer 43; for example, in addition to polygons, it can be circular, elliptical, star-shaped, heart-shaped, etc. The thickness of the base layer 43 is uniform throughout. However, the thickness of the base layer 43 does not have to be uniform.

[0031] Examples of the base material layer 43 include synthetic resins, FRP (Fiber Reinforced Plastics), carbon, glass, etc. Examples of synthetic resins 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 base material layer 43 may also be a composite material of these synthetic resins. In this embodiment, the base material layer 43 is composed of a PET film.

[0032] The thickness of the base layer 43 is 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 base layer 43 is preferably 500 μm or less, more preferably 130 μm or less, and even more preferably 100 μm or less.

[0033] The base layer 43 is preferably flexible. The Young's modulus of the base layer 43 is 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 base layer 43 is preferably 80 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less.

[0034] (Conductive layer 41) The conductive layer is a metallic microstructure portion consisting of a structure finer than the wavelength of the target radio wave (electromagnetic wave). The conductive layer corresponds to a split ring resonator in a metasurface (metamaterial) and is also called a split ring resonator (SRR). In this specification, the periodic pattern formed by the conductive layer 41 may be referred to as the "split ring resonant region" or simply the "resonant region".

[0035] The conductive layer 41 contains a conductor and constitutes a transparent surface. The conductive layer 41 is formed on the substrate layer 43. Methods for forming the conductive layer 41 on the substrate layer 43 include, for example, laminating a thin film in which the conductive layer 41 is embedded in a thin film dielectric onto the substrate layer 43, or forming the conductive layer 41 on the substrate layer 43 without using a dielectric.

[0036] Examples of conductors constituting the conductive layer 41 include one or more of silver, gold, copper, platinum, aluminum, titanium, silicon, indium tin oxide, and alloys (e.g., alloys containing nickel, chromium, and molybdenum). Examples of alloys containing nickel, chromium, and molybdenum include various grades such as Hastelloy B-2, B-3, C-4, C-2000, C-22, C-276, G-30, N, W, and X.

[0037] The thickness of the conductive layer 41 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 conductive layer 41 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 conductive layer 41 is 10 nm or more, an appropriate radio wave intensity can be ensured.

[0038] The conductive layer 41 preferably has a relative permittivity of 7 or higher. On the other hand, the upper limit of the relative permittivity is preferably 10,000 or less.

[0039] (Pattern of conductive layer 41) The conductive layer 41 is arranged in a plan view pattern, for example, as shown in Figure 2(B). When the conductive layer 41 has the plan view pattern shown in Figure 2(B), the radio wave permeator 4 functions as a bandpass filter that transmits radio waves in a predetermined frequency band. In this embodiment, the conductive layer 41 is arranged periodically in multiple layers vertically and horizontally in a pattern having a first conductive region 41C, a non-conductive region 42 surrounding the first conductive region 41C, and second conductive regions 41A, 41B surrounding the non-conductive region 42. In this way, the conductive layer 41 constitutes a divided ring resonance region 40 in the metasurface film 4, and the resonance region 40 is arranged periodically in multiple layers vertically and horizontally in a pattern having conductive regions 41 and non-conductive regions 42.

[0040] The first conductive region 41C is surrounded by a non-conductive region 42. The non-conductive region 42 is surrounded by one or more linear conductive regions 41A, 41B. The non-conductive region 42 is surrounded by the second conductive regions 41A, 41B.

[0041] In this embodiment, the first conductive region 41C is rectangular (square). The non-conductive region 42 encloses the outer periphery of the rectangular first conductive region 41C in a rectangular shape. The second conductive regions 41A and 41B enclose the outer periphery of the non-conductive region 42 in a rectangular shape. Specifically, linear conductive regions 41A and 41B are arranged at equal intervals along the vertical and horizontal directions, and the conductive region 41A along the horizontal direction and the conductive region 41B along the vertical direction are electrically conductive at their overlapping intersections, and these conductive regions 41A and 41B constitute the second conductive region.

[0042] The width W of the conductive region 42 is expressed as {(PA-PB) / 2}, which is half the difference between the length of the line segment PB connecting two opposite sides of the first conductive region 41C and the length of the line segment PA connecting two opposite sides of the second conductive region. Furthermore, if the gap GAP between adjacent non-conductive regions 42, 42 along the vertical or horizontal direction is used, the width of the second conductive regions 41A, 41B is expressed as GAP / 2. Note that the non-conductive regions 42 may be filled with adhesive from the adhesive layer 44.

[0043] (Other examples of patterns for conductive layer 41) Figures 5 to 7 illustrate other examples of patterns for the conductive layer 41 provided on the radio wave transparent material 4.

[0044] The conductive layer 41 can also be arranged in a plan view pattern, for example, as shown in Figure 5. When the conductive layer 41 has the plan view pattern shown in Figure 5, the radio wave permeable body 4 functions as a bandstop filter that blocks radio waves in a predetermined frequency band and transmits radio waves outside that frequency band.

[0045] In the example shown in Figure 5, the conductive layer 41 is a pattern having a first nonconductive region 42C, a conductive region 41 surrounding the first nonconductive region 42C, and second nonconductive regions 42A and 42B surrounding the conductive region 41, and multiple such patterns are arranged periodically in the vertical and horizontal directions. The first nonconductive region 42C is surrounded by the conductive region 41. The conductive region 41 is surrounded by one or more linear nonconductive regions 42A and 42B. The conductive region 41 is surrounded by the second nonconductive regions 42A and 42B. In this way, the conductive layer 41 constitutes a divided ring resonance region 40 in the metasurface film 4, and the resonance region 40 is a pattern having conductive regions 41 and nonconductive regions 42, and multiple such resonance regions are arranged periodically in the vertical and horizontal directions.

[0046] In this example, the first non-conductive region 42C is rectangular (square). The conductive region 41 encloses the outer periphery of the rectangular first non-conductive region 42C in a rectangular shape. The second non-conductive regions 42A and 42B enclose the outer periphery of the conductive region 41 in a rectangular shape. Specifically, linear non-conductive regions 42A and 42B are arranged at equal intervals along the vertical and horizontal directions, and the non-conductive region 42A along the horizontal direction and the non-conductive region 42B along the vertical direction are connected at their overlapping intersections, and these non-conductive regions 42A and 42B constitute the second non-conductive region.

[0047] The width W of the conductive region 41 is expressed as {(PA-PB) / 2}, which is half the difference between the length of the line segment PB connecting two opposite sides of the first nonconductive region 42C and the length of the line segment PA connecting two opposite sides of the second nonconductive region. Furthermore, if the gap GAP between conductive regions 41, 41 in adjacent patterns along the vertical or horizontal direction is used, the width of the second nonconductive regions 42A, 42B is expressed as GAP / 2. Note that the adhesive of the adhesive layer 44 may be filled into the nonconductive regions 42 (42A, 42B, 42C).

[0048] The conductive layer 41 can also be arranged in a plan view pattern, for example, as shown in Figure 6. When the conductive layer 41 has the plan view pattern shown in Figure 6, the radio wave transparent body 4 functions as a low-pass filter that transmits radio waves below a predetermined frequency.

[0049] In the example shown in Figure 6, the conductive region 41 is rectangular (square) in plan view and is demarcated by the non-conductive region 42. In this example, the non-conductive region 42 is linear and surrounds the conductive region 41 with two regions 42 (42A) along the horizontal direction and two regions 42 (42B) along the vertical direction. Thus, the conductive layer 41 constitutes a divided ring resonant region in the metasurface film 4, and the resonant region is a pattern having conductive regions 41 and non-conductive regions 42, arranged periodically in multiple locations in the vertical and horizontal directions. The outer edge of one resonant region is located in the center of the width direction of each non-conductive region 42 (42A, 42B). As exemplary dimensions, in this embodiment, the line width L6 of the non-conductive region 42 is approximately 0.4 mm, and the length L7 of one side of the rectangular (square) conductive region 41 is, for example, approximately 5.265 mm. The non-conductive region 42 may be filled with adhesive from the adhesive layer 44. The non-conductive region 42 can also be called the region without the conductive layer 41.

[0050] (Protective film 45) The protective film 45 can protect the conductive layer 41 by covering it. The protective film 45 has a size corresponding to the base layer 43 in a plan view. Examples of the protective film 45 include a film made of synthetic resin. Examples of synthetic resins 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.

[0051] The protective film 45 preferably contains fluorine. A protective film 45 containing fluorine can prevent the transmission of ultraviolet light, thereby protecting the conductive layer 41 from ultraviolet light.

[0052] The thickness of the protective film 45 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 45 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 25 μm or less.

[0053] The protective film 45 is bonded to the substrate layer 43 via an adhesive layer (hereinafter referred to as the second adhesive layer 44). The second adhesive layer 44 can be made of, for example, a synthetic resin or a rubber adhesive sheet. Examples of synthetic resins include acrylic resin, silicone resin, and polyvinyl alcohol resin.

[0054] <Variation> The above embodiments are merely one of many embodiments of the present invention. The embodiments can be modified in various ways depending on the design, etc., as long as the objectives of the present invention are achieved. The following lists some modifications of the embodiments. The modifications described below can be combined and applied as appropriate.

[0055] (Variation 1) In the above embodiment, the window material 1 had multiple transparent plates 2, but as shown in Figure 7, the window material 1 may have only one transparent plate 2. As shown in Figure 7, a metal layer 3 is laminated on the first surface 211 of the transparent plate 2. The radio wave permeable material 4 is attached to the metal layer 3. The radio wave permeable material 4 may also be attached to the second surface 212, which does not have a metal layer 3.

[0056] Furthermore, the metal layer 3 is not limited to a Low-E film, but may also be a heat-shielding film. If the metal layer 3 is a heat-shielding film, for example, it may be attached to the first surface 211 or the second surface 212 of the transparent plate 2 after the window material 1 has been installed in the window frame.

[0057] (Modification 2) In the above embodiment, the radio wave permeable material 4 was attached to a transparent plate 2 (first transparent plate 21) on which the metal layer 3 was laminated. However, as shown in Figure 8, the radio wave permeable material 4 may be attached to a transparent plate 2 (second transparent plate 22) that is different from the transparent plate 2 on which the metal layer 3 was laminated.

[0058] The distance between the radio wave permeable material 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 radio wave permeable material 4 and the metal layer 3 may be 0 mm. That is, the radio wave permeable material 4 may be directly bonded to the metal layer 3 (see Figure 7).

[0059] <Examples> In this embodiment, the degree to which radio wave transmission is improved by placing a radio wave permeable material on the surface of the window material was confirmed by numerical simulation. The numerical simulation was performed based on the waveguide model 9 shown in Figure 9. In the radio wave permeable material included in the illustrated waveguide model 9, the patterns of the conductive layers shown in Figures 10, 12, 14, and 17 (i.e., the conditions of the metastructure) were defined, and in this defined waveguide model 9, the radio wave intensity transmitted through the window material and the strength and direction of the currents flowing through the conductive layer 41 and the metal layer 3 were calculated. The strength and direction of the current in the entire conductive layer 41 (hereinafter also referred to as the current vector) was taken as the average of multiple current vectors calculated in the conductive layer 41. The current vector in the entire metal layer 3 was the same as the current vector in the entire conductive layer 41.

[0060] To facilitate understanding of the examples, in Figures 10 to 18, the same reference numerals are used for components that are the same as those described in the above-described embodiments. The thickness of each layer in waveguide model 9 was as follows: the radio wave permeable 4 (metasurface film) was 101.4 μm (breakdown: conductive layer 41 was 1.4 μm, and substrate layer 43 was 100 μm), the first transparent plate 21 (glass) was 5 mm, the metal layer 3 (Low-E film) was 100 nm, the intermediate layer 6 (air) was 5 mm, and the second transparent plate 22 (glass) was 5 mm.

[0061] (Bandpass filter) Figures 10 and 11 illustrate the results of numerical simulations regarding the pattern of a conductive layer that functions as a bandpass filter. Figure 10(A) shows the planar structure of the conductive layer used in the numerical simulation. In Figure 10(A), line segment PA is 20 cm, line segment PB is 10 cm, and the gap P is 1 cm. Figure 10(B) is a graph showing the results of a numerical simulation regarding the radio wave transmittance of the radio wave permeable material. The vertical axis of the graph represents the radio wave transmittance through the metal layer 3 (Low-E film) provided in the window material 1 shown in Figure 1. Figure 11(A) shows the direction of the current flowing through the conductive layer. Figure 11(B) shows the direction of the current flowing through the metal layer (Low-E film) provided in the window material. In both Figure 11(A) and Figure 11(B), the direction of the current throughout the entire layer is shown at the left end.

[0062] We will examine the bandpass filters shown in Figures 10 and 11. As shown in Figure 10(B), it was confirmed that the radio wave transmission performance was good in the 5G frequency band (3GHz to 5GHz), and that it functioned as a bandpass filter. Furthermore, it was confirmed that the direction of the current flowing through the conductive layer 41 and the direction of the current flowing through the metal layer 3 were not the same, as shown in Figure 11, but were generally opposite.

[0063] (Bandstop filter) Figures 12 and 13 illustrate the results of numerical simulations regarding the pattern of the conductive layer that functions as a bandstop filter. The positioning of each figure is the same as in Figures 10 and 11. In Figure 12(A), line segment PA is 10 cm, line segment PB is 20 cm, and the gap P is 1 cm.

[0064] We will examine the bandstop filter shown in Figures 12 and 13. As shown in Figure 12(B), in the 5G frequency band (3GHz to 5GHz), the radio wave transmission performance was reduced, confirming that it was functioning as a bandstop filter. Furthermore, as shown in Figure 13, it was confirmed that the direction of the current flowing through the conductive layer 41 and the direction of the current flowing through the metal layer 3 were not the same, but generally opposite.

[0065] (Low-pass filter) Figures 14 and 15 illustrate the results of numerical simulations regarding the pattern of a conductive layer that functions as a low-pass filter. The positioning of each figure is the same as in Figures 10 and 11. In Figure 14(A), the line width L6 was set to 0.6 cm and the length L7 to 7.02 cm.

[0066] We will examine the low-pass filters shown in Figures 14 and 15. As shown in Figure 14(B), it was confirmed that the radio wave transmission performance was good at frequencies lower than the 5G frequency band (3GHz to 5GHz), and that it functioned as a low-pass filter. Furthermore, it was confirmed that the direction of the current flowing through the conductive layer 41 and the direction of the current flowing through the metal layer 3 were not the same, as shown in Figure 15, but were generally opposite. [Explanation of Symbols]

[0067] 1 Window materials 2 transparent plate 21 1st transparent plate 211 Page 1 212 2nd page 22 Second transparent plate 221 Page 1 222 2nd page 3 metal layer 4. Radio wave transparent material (metasurface film) 41 Conductive layer (conductive region) 42 Non-conductive area 43 Base material layer 44 Adhesive layer (second adhesive layer) 45 protective film 46 Adhesive layer (1st adhesive layer) 5 Spacers 6. Mesopotamian

Claims

1. A light-transmitting radio wave permeator disposed on the surface of a window material comprising at least one transparent plate and a metal layer laminated on the at least one transparent plate, A conductive layer, A substrate layer supporting the conductive layer, Equipped with, The conductive layer has a pattern having conductive regions and non-conductive regions, and multiple layers are arranged periodically in the vertical and horizontal directions. A radio wave transparent material in which the direction of the current flowing through the conductive layer when radio waves are incident on it is opposite to the direction of the current flowing through the metal layer when radio waves are incident on it.

2. The radio wave transparent material according to claim 1, wherein the angle (boundary angle) between the direction of the current flowing through the conductive layer and the direction of the current flowing through the metal layer is within the range of 125° to 180°.

3. The radio wave transparent body according to claim 1, wherein the conductive layer has a pattern in which conductive regions and non-conductive regions surrounding the conductive regions are arranged periodically in the vertical and horizontal directions.

4. The radio wave transparent body according to claim 1, wherein the conductive layer has a pattern in which a first conductive region, a non-conductive region surrounding the first conductive region, and a second conductive region surrounding the non-conductive region are arranged periodically in the vertical and horizontal directions.

5. The radio wave transparent body according to claim 1, wherein the conductive layer has a pattern in which a first nonconductive region, a conductive region surrounding the first nonconductive region, and a second nonconductive region surrounding the conductive region are arranged periodically in the vertical and horizontal directions.

6. At least one transparent plate, A metal layer laminated on at least one of the transparent plates, A radio wave transparent material according to any one of claims 1 to 5, attached to the transparent plate or the metal layer, Window material equipped with [a specific feature / feature].

Images