Radio-wave-transmitting body and window material

Abstract

Provided is a technology for easily enhancing the radio wave transmissivity of a window material. A translucent radio-wave-transmitting body 4 is disposed on the surface of a window material 1 comprising a transparent sheet 2 and a metal layer 3 layered on the transparent sheet 2. The radio-wave-transmitting body 4 comprises an electroconductive layer 41 and a substrate layer 43. The electroconductive layer 41 includes multiple electroconductive regions 41 and non-electroconductive regions 42 enclosing the electroconductive regions 41, which are disposed vertically and horizontally in a periodical manner. The regions 41 are each defined by the length of a line segment that passes through the center of gravity of the region 41 and joins both ends of the region 41. The length of the line segment is the length obtained by subtracting the interval between the regions 41 that are adjacent from the distance between the centers of gravity of adjacent regions 41. The length of the line segment, the length of the interval, the frequency of the incident radio wave, and the radio wave intensity after transmission satisfy a specific combination. According to one combination, the length of the line segment is 5.3 mm to 31.6 mm, the length of the interval between adjacent regions 41 is 0.1 mm to 15 mm, and the radio wave intensity after transmission of an incident radio wave having a frequency of 3.5 GHz is 1 dB or greater.

Description

Radio wave transmitting body and window material

[0001] The present invention relates to a radio wave transmitting body that is placed on the surface of a window material, and to a window material that includes a radio wave transmitting body.

[0002] In recent years, window glass (hereinafter referred to as window material) with excellent heat blocking properties in summer and heat insulating properties in winter has become increasingly popular as an energy-saving measure for buildings. In such window materials, a Low-E film is formed on the entire surface of one of the surfaces that constitutes the window material.

[0003] On the other hand, it is known that when a Low-E film is formed on a window material, the transmittance of radio waves decreases over a wide frequency band. The occurrence of radio wave blind zones inside a building is a problem for the widespread use of high-speed wireless communications, such as 5G, that make up mobile phone networks. Therefore, in conventional window materials, as in Patent Document 1, for example, a radio wave transmittance area is formed by removing a portion of the Low-E film using laser processing, thereby improving the indoor radio wave communication environment.

[0004] Japanese Patent Application Laid-Open No. 2023-113772

[0005] However, when manufacturing a window material, removing a portion of the Low-E film as in Patent Document 1 cannot be said to be efficient for production. Moreover, it is not realistic to perform such a Low-E film removal process on window materials that have already been installed in buildings. There is a need for a technology that can easily increase the radio wave transmittance of window materials.

[0006] An object of the present invention is to provide a technique for easily increasing the radio wave transmittance of a window material.

[0007] In order to achieve the above object, the present invention encompasses the following subjects: (Item 1) A light-transmitting radio wave transmitting body 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, comprising: a conductive layer; and a base layer supporting the conductive layer, wherein the conductive layer has a plurality of conductive regions and non-conductive regions surrounding the conductive regions periodically arranged lengthwise and widthwise, wherein the conductive regions are regions defined by the length of a line segment passing through the center of gravity of the conductive region and connecting both ends of the conductive region, the length of the line segment being the distance between the centers of gravity of adjacent conductive regions minus the interval between adjacent conductive regions, wherein a combination of the length of the line segment, the length of the interval, the frequency of the incident radio wave, and the radio wave intensity after transmission is: the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the interval is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 3.5 GHz is 1 dB or more; A radio wave transparent body according to any one of the following combinations: a second combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 3.7 GHz is 1 dB or more, a third combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 4.5 GHz is 1 dB or more, and a fourth combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 4.7 GHz is 1 dB or more. (Item 2) The radio wave transparent body according to item 1, wherein the conductive region is a rectangle surrounded by one or more linear non-conductive regions. (Item 3) The radio wave transmitting body according to Item 2, wherein in the first combination, the length of the line segment is 5.3 mm or more and 15.8 mm or less, the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 4 dB or more. (Item 4) The radio wave transmitting body according to Item 3, wherein the length of the gap is 0.4 mm or more and 13 mm or less, and the radio wave intensity after transmission is 6 dB or more.(Item 5) The radio wave transmission body according to Item 4, wherein the length of the line segment is 6.3 mm or more and 15.8 mm or less, the length of the gap is 0.5 mm or more and 13 mm or less, and the radio wave intensity after transmission is 8 dB or more. (Item 6) The radio wave transmission body according to Item 2, wherein in the second combination, the length of the gap is 0.4 mm or more and 15 mm or less, and the radio wave intensity after transmission is 4 dB or more. (Item 7) The radio wave transmission body according to Item 6, wherein the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 6 dB or more. (Item 8) The radio wave transmission body according to Item 7, wherein the length of the line segment is 5.3 mm or more and 12.6 mm or less, and the radio wave intensity after transmission is 8 dB or more. (Item 9) The radio wave transmission body according to Item 2, wherein in the third combination, the length of the gap is 0.4 mm or more and 15 mm or less, and the radio wave intensity after transmission is 4 dB or more. (Item 10) The radio wave transmission body according to Item 9, wherein the length of the line segment is 5.3 mm or more and 21.1 mm or less, and the radio wave intensity after transmission is 5 dB or more. (Item 11) The radio wave transmission body according to Item 10, wherein the length of the line segment is 5.3 mm or more and 12.6 mm or less, the length of the gap is 0.4 mm or more and 13 mm or less, and the radio wave intensity after transmission is 6 dB or more. (Item 12) The radio wave transmission body according to Item 2, wherein in the fourth combination, the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 4 dB or more. (Item 13) The radio wave transmission body according to Item 12, wherein the length of the gap is 0.5 mm or more and 14 mm or less, and the radio wave intensity after transmission is 5 dB or more. (Item 14) A window material comprising: at least one transparent plate; a metal layer laminated on the at least one transparent plate; and the radio wave transmitting body according to any one of Items 1 to 13 attached to the transparent plate or the metal layer.

[0008] According to the present invention, a technique for easily increasing the radio wave transmittance of a window material can be provided.

[0009] 1 is a cross-sectional view of a window material according to an embodiment; FIG. 2 is a diagram showing a schematic configuration of the entire radio wave transmitting body according to an embodiment; (A) is a plan view, and (B) is an enlarged view of part A of (A); FIG. 3 is a cross-sectional view of a radio wave transmitting body according to an embodiment; FIG. 4 is a diagram for explaining another example of the pattern of the conductive layer provided on the radio wave transmitting body; FIG. 5 is a cross-sectional view of a window material according to modified example 1; FIG. 6 is a cross-sectional view of a window material according to modified example 2; FIG. 7 is a waveguide model used in a numerical simulation according to an example; FIG. 8 is a pattern of the conductive layer used in a numerical simulation according to an example; FIG. 9 is a scatter diagram for explaining the results of a numerical simulation according to an example (incident radio waves 3.5 GHz); FIG. 10 is a scatter diagram for explaining the results of a numerical simulation according to an example (incident radio waves 3.7 GHz); FIG. 11 is a scatter diagram for explaining the results of a numerical simulation according to an example (incident radio waves 4.5 GHz); FIG. 12 is a scatter diagram for explaining the results of a numerical simulation according to an example (incident radio waves 4.7 GHz).

[0010] Embodiments of the present invention will now be described with reference to the drawings. A window material 1 according to this embodiment has a light-transmitting radio wave transmitting body 4 disposed on its surface. Although the window material 1 according to this embodiment has reduced radio wave transmittance over a wide frequency band due to the inclusion of the metal layer 3, the radio wave transmittance body 4, which is a metasurface film, disposed on the surface improves radio wave transmittance.

[0011] First, the window material 1 on which the radio wave transmitting body 4 is disposed will be described below. Next, each component of the window material 1, including the radio wave transmitting body 4, will be described.

[0012] (Window Material) As shown in Fig. 1 , the window material 1 is a double glazing having a plurality of transparent plates 2. The window material 1 includes the plurality of transparent plates 2, a metal layer 3, and a radio wave transmitting body 4. The window material 1 also includes a spacer 5 that maintains a distance between the plurality of transparent plates 2.

[0013] As shown in FIGS. 2 and 3, the radio wave transmitting body 4 includes a base layer 43 attached to the transparent plate 2 or the metal layer 3, and a conductive layer 41 formed on the base layer 43.

[0014] Because the window material 1 according to this embodiment is configured in this manner, it is possible to increase the radio wave transmittance only for radio waves in a specific frequency band, even if the metal layer 3 reflects or blocks radio waves. Moreover, because it is only necessary to attach the radio wave transmitting body 4 to the window material 1 on which the existing metal layer 3 is laminated, the window material 1 can be made highly manufacturable.

[0015] The window material 1 according to this embodiment is used, for example, as window glass in buildings, as well as light-receiving windows in doors, fixed windows in ceilings, floors, etc. Furthermore, the window material 1 according to this embodiment can also be used for windows in automobiles, aircraft, ships, trains, ropeways, etc. in addition to buildings.

[0016] In the window material 1, the specific frequency band of radio waves that can enhance the radio wave transmittance is preferably any radio wave in the range of 0.5 GHz to 60 GHz. In this embodiment, the transparent plate 2 is configured to enhance the radio wave transmittance in the 5 GHz 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 transmittance of the window material 1 is to be enhanced. The specific frequency band in which the radio wave transmittance is to be enhanced can be set to a desired frequency band by changing the shape of the conductive layer 41 in the radio wave transmitting body 4.

[0017] (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. Furthermore, the transparent plate 2 is not limited to being colorless and transparent, and may be colored.

[0018] The transparent plate 2 according to the present embodiment is preferably a glass plate. Examples of the glass plate include float glass, figured glass, frosted glass, wired glass, and tempered glass. However, examples of the transparent plate 2 include an acrylic plate and a polycarbonate plate in addition to a glass plate.

[0019] There are no particular limitations on the shape of the transparent plate 2. The shape of the transparent plate 2 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 2 is viewed from a direction perpendicular to the main surface.

[0020] 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 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."

[0021] 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 transparent plates 2 are surrounded by a sealing material (not shown), and the space (intermediate layer 6) between the two adjacent transparent plates 21, 22 is formed airtight. The intermediate layer 6 is preferably filled with an insulating gas. Examples of the insulating gas include an inert gas such as argon gas. However, the intermediate layer 6 may also be filled with air. Alternatively, the intermediate layer 6 may be a vacuum.

[0022] 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 the first surfaces 211 and 221. In this embodiment, the first surfaces 211 and 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 and 222 refer to outer surfaces of the window material 1.

[0023] The window material 1 in this embodiment is a double-pane glass made up of two transparent plates 2, but it may also be a triple-pane glass made up of three transparent plates 2, or it may be made up of four or more transparent plates 2.

[0024] (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.

[0025] 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.

[0026] (Radio wave transmitting body 4) The radio wave transmitting body 4 is attached to the transparent plate 2 or the metal layer 3. By attaching the radio wave transmitting body 4 to the transparent plate 2 or the metal layer 3, it is possible to increase the radio wave transmittance of the window material 1 in a specific frequency band of radio waves. As shown in Figures 2 and 3, the radio wave transmitting body 4 has a base layer 43, a conductive layer 41, and a protective film 45 laminated in this order. The radio wave transmitting body 4 according to this embodiment is attached to the second surface 212 of the first transparent plate 21. The radio wave transmitting body 4 may cover the entire surface of the transparent plate 2, or may be attached to only a part of the entire surface.

[0027] (Substrate Layer 43) The substrate layer 43 supports the conductive layer 41. In this embodiment, the substrate layer 43 is transparent. The substrate layer 43 is attached to the transparent plate 2 or the metal layer 3. An adhesive layer (hereinafter referred to as the first adhesive layer 46) is provided on the surface of the substrate layer 43 opposite the conductive layer 41. The first adhesive layer 46 preferably has a large number of capsules filled with adhesive before bonding, and is structured so that the adhesive ruptures when pressure is applied from the substrate layer 43 toward the transparent plate 2 or the metal layer 3 during bonding, thereby enabling bonding. However, the first adhesive layer 46 may also be an adhesive applied without being filled into capsules. Examples of adhesives include synthetic resins such as acrylic resin, silicone resin, and polyvinyl alcohol resin.

[0028] In this embodiment, the outer shape of the base material layer 43 is quadrangular (more specifically, square) in plan view, as shown in Fig. 2. However, there are no particular limitations on the shape of the base material layer 43, and examples thereof include a polygon, a circle, an ellipse, a star, a heart, and the like. The thickness of the base material layer 43 is uniform over the entire surface. However, the thickness of the base material layer 43 does not have to be uniform.

[0029] Examples of the substrate layer 43 include synthetic resin, fiber reinforced plastics (FRP), 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 layer 43 may be a composite material of these synthetic resins. The substrate layer 43 according to this embodiment is made of a PET film.

[0030] The thickness of the base layer 43 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 base layer 43 is, for example, preferably 500 μm or less, more preferably 130 μm or less, and even more preferably 100 μm or less.

[0031] The base layer 43 preferably has flexibility. The modulus of longitudinal elasticity of the base layer 43 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 modulus of longitudinal elasticity of the base layer 43 is, for example, preferably 80 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less.

[0032] (Conductive layer 41) The conductive layer is a metal microstructure having a structure finer than the wavelength of the target radio waves (electromagnetic waves). 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 40 formed by the conductive layer 41 may be referred to as a "split ring resonator portion" or simply as a "resonator portion."

[0033] The conductive layer 41 includes a conductor and constitutes a transmission surface. The conductive layer 41 is formed on a base layer 43. Methods for forming the conductive layer 41 on the base layer 43 include, for example, laminating a thin film formed by embedding the conductive layer 41 in a thin-film dielectric on the base layer 43, or forming the conductive layer 41 on the base layer 43 without using a dielectric.

[0034] Examples of the conductor constituting the conductive layer 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.

[0035] 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, appropriate radio wave intensity can be ensured.

[0036] The conductive layer 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.

[0037] (Pattern of Conductive Layer 41) The conductive layer 41 is arranged in a pattern in a plan view as shown in Fig. 2B, for example. In this specification, when describing the conductive layer 41 by focusing on the pattern in a plan view, the conductive layer 41 is described as a conductive region 41.

[0038] As shown in FIG. 2B , the radio wave transmitting body 4 (metasurface film 4) has multiple split-ring resonators 40 (resonator 40) periodically arranged in the vertical and horizontal directions. Each resonator 40 has a conductive region 41 and a non-conductive region 42. In this embodiment, the conductive regions 41 are arranged at equal intervals along the vertical and horizontal directions, and the conductive region 41 is surrounded by one or more linear non-conductive regions 42. In this embodiment, the conductive regions 41 are rectangular (square) and periodically arranged at intervals equal to the line width L6 of the non-conductive region 42. In this embodiment, the conductive region 41 is surrounded by a non-conductive region 42 (42A) extending along the horizontal direction and a non-conductive region 42 (42B) extending along the vertical direction. The length L7 of one side of the square conductive region 41 (the length between adjacent non-conductive regions 42 along the vertical or horizontal direction) is set to be greater than the wavelength of visible light but less than the wavelength of radio waves passing through the radio wave transmitting body 4. The non-conductive region 42 may be filled with the adhesive of the adhesive layer 44 .

[0039] 4 is a diagram illustrating another example of the pattern of the conductive layer 41 provided on the radio wave transmitting body 4. In this embodiment, the pattern of the conductive region 41 is rectangular (square) in plan view, but the pattern of the region 41 is not limited to a rectangle. The pattern of the conductive region 41 can be a pattern that satisfies the conditions described below.

[0040] That is, in a pattern in which a plurality of conductive regions 41 are periodically arranged vertically and horizontally, surrounded by non-conductive regions 42, each conductive region 41 is defined by the length of a line segment that passes through the center of gravity of the region 41 and connects both ends of the region 41. The length of this line segment is the distance between the centers of gravity of adjacent regions 41 minus the spacing between the multiple regions 41. As shown below as examples for several shapes, the conductive region 41 can be defined by the length of such a line segment that passes through the center of gravity of the region 41 and connects both ends of the region 41.

[0041] 4A shows an example in which the conductive region 41 is circular. In the example shown in FIG. 4A, the conductive region 41 is formed by a line segment a １ b １ The length of the line segment a １ b １ is the center of gravity C of the region 41 １ The length of the line segment a1b1 is the distance from the center of gravity C of the adjacent region 41. １ , C ２ From the distance between the adjacent regions 41 (line segment b １ a ２ The length is the length minus the length of the

[0042] In the circular example shown in FIG. 4A, the conductive area 41 is １ b １ Instead of the length of the line segment d １ e １ It can also be defined by the length of the line segment d １ e １ is the center of gravity C of the region 41 １ The line segment d passes through and connects both ends of the region 41. １ e １ The length of the center of gravity C of the adjacent region 41 １ , C ３From the distance between the adjacent regions 41 (line segment e １ d ３ The length is the length minus the length of the

[0043] 4B shows an example in which the conductive region 41 is a regular pentagon. In the example shown in FIG. 4B, the conductive region 41 is formed by a line segment a １ b １ As in FIG. 4A, the length of the line segment a １ b １ is the center of gravity C of the region 41 １ The line segment a passes through and connects both ends of the region 41. １ b １ The length of the center of gravity C of the adjacent region 41 １ , C ２ From the distance between the adjacent regions 41 (line segment b １ a ２ The length is the length minus the length of the

[0044] In the example of a regular pentagon shown in FIG. 4B, the conductive region 41 is １ b １ Instead of the length of the line segment d １ e １ It can also be defined by the length of the line segment d １ e １ is the center of gravity C of the region 41 １ The line segment d passes through and connects both ends of the region 41. １ e １ The length of the center of gravity C of the adjacent region 41 １ , C ３ From the distance between the adjacent regions 41 (line segment e １ d ３ The length is the length minus the length of the

[0045] (Protective Film 45) The protective film 45 can protect the conductive layer 41 by covering the conductive layer 41. The protective film 45 has a size corresponding to the base material layer 43 in a plan view. Examples of the protective film 45 include films made of synthetic resins. 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.

[0046] The protective film 45 preferably contains fluorine. The protective film 45 containing fluorine can prevent transmission of ultraviolet rays, and therefore can protect the conductive layer 41 from ultraviolet rays.

[0047] 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.

[0048] The protective film 45 is adhered to the base layer 43 via an adhesive layer (hereinafter referred to as the second adhesive layer 44). Examples of the second adhesive layer 44 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.

[0049] <Modifications> 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.

[0050] (Variation 1) In the above embodiment, the window material 1 has multiple transparent plates 2, but as shown in Fig. 5, the window material 1 may have only one transparent plate 2. As shown in Fig. 5, a metal layer 3 is laminated on a first surface 211 of the transparent plate 2. A radio wave transmitting body 4 is attached to the metal layer 3. Note that the radio wave transmitting body 4 may also be attached to a second surface 212 on which no metal layer 3 is provided.

[0051] 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 the window frame.

[0052] (Variant 2) In the above embodiment, the radio wave transparent body 4 was attached to a transparent plate 2 (first transparent plate 21) on which the metal layer 3 was laminated, but as shown in Figure 6, the radio wave transparent body 4 may also be attached to a transparent plate 2 (second transparent plate 22) other than the transparent plate 2 on which the metal layer 3 was laminated.

[0053] The distance between the radio wave transmitting body 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 transmitting body 4 and the metal layer 3 may be 0 mm. In other words, the radio wave transmitting body 4 may be directly bonded to the metal layer 3 (see FIG. 5 ).

[0054] Example In this example, the degree to which radio wave transmission is improved by placing a radio wave transmitting body on the surface of a window material was confirmed by numerical simulation. The numerical simulation was performed based on the waveguide model 9 shown in Fig. 7. For the radio wave transmitting body included in the illustrated waveguide model 9, the conductive layer pattern (i.e., the metastructure conditions) shown in Fig. 8 was specified, and the intensity of radio waves transmitted through the window material was calculated for this specified waveguide model 9.

[0055] The dimensions PA and GAP shown in FIG. 8 were defined as variables defining the pattern of the conductive layer of the radio wave transmitting body. The radio wave intensity transmitted through the window material was calculated by comprehensively combining the multiple conditions (numerical ranges) shown in Table 1 and comprehensively varying these defined 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 transmitted through the window material was calculated for each of these. In this example, the frequencies of the radio waves incident on the window material were 3.5 GHz, 3.7 GHz, 4.5 GHz, and 4.7 GHz. A comprehensive numerical simulation was performed for each of these four frequencies, varying the conditions among the 165 types described above. The value calculated by subtracting the following radio wave intensity from the radio wave intensity transmitted through the window material (Low-E) was used as the intensity of the incident radio wave. When the frequency of the incident radio wave is 3.5 GHz, the intensity of the radio wave transmitted through the window material (Low-E) was calculated by subtracting 60.9578 dB. Similarly, when the frequency of the incident radio wave is 3.5 GHz, 61.619 dB was subtracted from the intensity of the radio wave transmitted through the window material (Low-E), when the frequency of the incident radio wave is 4.5 GHz, 63.3631 dB was subtracted, and when the frequency of the incident radio wave is 4.7 GHz, 63.5783 dB was subtracted. The results of the numerical simulation are shown in Figure 9 (3.5 GHz), Figure 10 (3.7 GHz), Figure 11 (4.5 GHz), and Figure 12 (4.7 GHz). When considering the results, it was determined that the radio wave transmittance was improved when the radio wave intensity after transmission of the incident radio wave was 1 dB or more.

[0056]

[0057] 7 and 8, the same components as those described in the above embodiment are denoted by the same reference numerals. Dimension PA corresponds to the line segment passing through the center of gravity of conductive region 41 and connecting both ends of region 41, as described with reference to FIG. 4. Symbol CG is the center of gravity of conductive region 41. Dimension GAP corresponds to the spacing between adjacent conductive regions 41, as described with reference to FIG. 4.

[0058] The scatter diagram of FIG. 9 plots combinations of dimensions PA and GAP that, in a numerical simulation, resulted in an incident radio wave frequency of 3.5 GHz and an intensity of the radio wave transmitted through the window material of 4 dB or more.

[0059] 9A shows a combination of dimensions for which the radio wave intensity is 4 dB or more. As shown in FIG. 9A, when the dimension PA is 5.3 mm or more and 15.8 mm or less, and the dimension GAP is 0.4 mm or more and 14 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 4 dB or more.

[0060] 9B shows a combination of dimensions for which the radio wave intensity is 6 dB or more. As shown in FIG. 9B, when the dimension PA is 5.3 mm or more and 15.8 mm or less, and the dimension GAP is 0.4 mm or more and 13 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 6 dB or more.

[0061] 9C shows a combination of dimensions for which the radio wave intensity is 8 dB or more. As shown in FIG. 9C, when the dimension PA is 6.3 mm or more and 15.8 mm or less, and the dimension GAP is 0.5 mm or more and 13 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 8 dB or more.

[0062] The scatter diagram of FIG. 10 plots combinations of dimensions PA and GAP that, in a numerical simulation, resulted in an incident radio wave frequency of 3.7 GHz and an intensity of the radio wave transmitted through the window material of 4 dB or more.

[0063] Fig. 10A shows a combination of dimensions for which the radio wave intensity is 4 dB or more. As shown in Fig. 10A, when the dimension PA is 5.3 mm or more and 31.6 mm or less, and the dimension GAP is 0.4 mm or more and 15 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 4 dB or more.

[0064] Fig. 10(B) shows a combination of dimensions for which the radio wave intensity is 6 dB or more. As shown in Fig. 10(B), when the dimension PA is 5.3 mm or more and 31.6 mm or less, and the dimension GAP is 0.4 mm or more and 14 mm or less, a numerical simulation showed that radio waves can be transmitted with an intensity of 6 dB or more.

[0065] Fig. 10C shows a combination of dimensions that results in a radio wave intensity of 8 dB or more. As shown in Fig. 10C, when the dimension PA is 5.3 mm or more and 12.6 mm or less, and the dimension GAP is 0.4 mm or more and 14 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 8 dB or more.

[0066] The scatter diagram of FIG. 11 plots combinations of dimensions PA and GAP that, in a numerical simulation, resulted in an incident radio wave frequency of 4.5 GHz and an intensity of the radio wave transmitted through the window material of 4 dB or more.

[0067] 11A shows a combination of dimensions that results in a radio wave intensity of 4 dB or more. As shown in FIG. 11A, when the dimension PA is 5.3 mm or more and 31.6 mm or less, and the dimension GAP is 0.4 mm or more and 15 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 4 dB or more.

[0068] Fig. 11(B) shows the combination of dimensions for which the radio wave intensity is 5 dB or more. As shown in Fig. 11(B), when the dimension PA is 5.3 mm or more and 21.1 mm or less, and the dimension GAP is 0.4 mm or more and 15 mm or less, a numerical simulation showed that radio waves can be transmitted with an intensity of 5 dB or more.

[0069] Fig. 11C shows a combination of dimensions that results in a radio wave intensity of 6 dB or more. As shown in Fig. 11C, when the dimension PA is 5.3 mm or more and 12.6 mm or less, and the dimension GAP is 0.4 mm or more and 13 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 6 dB or more.

[0070] The scatter diagram of FIG. 12 plots combinations of dimensions PA and GAP that, in a numerical simulation, resulted in an incident radio wave frequency of 4.7 GHz and an intensity of the radio wave transmitted through the window material of 4 dB or more.

[0071] Fig. 12A shows the combination of dimensions that results in a radio wave intensity of 4 dB or more. As shown in Fig. 12A, when the dimension PA is 5.3 mm or more and 31.6 mm or less, and the dimension GAP is 0.4 mm or more and 14 mm or less, a numerical simulation showed that radio waves penetrate with an intensity of 4 dB or more.

[0072] Fig. 12(B) shows a combination of dimensions for which the radio wave intensity is 5 dB or more. As shown in Fig. 12(B), when the dimension PA is 5.3 mm or more and 31.6 mm or less, and the dimension GAP is 0.5 mm or more and 14 mm or less, a numerical simulation showed that radio waves can be transmitted with an intensity of 5 dB or more.

[0073] REFERENCE SIGNS LIST 1 window material 2 transparent plate 21 first transparent plate 211 first surface 212 second surface 22 second transparent plate 221 first surface 222 second surface 3 metal layer 4 radio wave transparent body (metasurface film) 40 split ring resonator 41 conductive layer (conductive region) 42 non-conductive region 43 substrate layer 44 adhesive layer (second adhesive layer) 45 protective film 46 adhesive layer (first adhesive layer) 5 spacer 6 intermediate layer

Claims

1. A light-transmitting radio wave transmitting body 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, comprising: a conductive layer; and a base layer supporting the conductive layer; wherein the conductive layer has a plurality of conductive regions and non-conductive regions surrounding the conductive regions periodically arranged lengthwise and widthwise; wherein the conductive regions are regions defined by the length of a line segment passing through the center of gravity of the conductive region and connecting both ends of the conductive region, the length of the line segment being the distance between the centers of gravity of adjacent conductive regions minus the interval between adjacent conductive regions; and a first combination of the length of the line segment, the length of the interval, the frequency of the incident radio wave, and the radio wave intensity after transmission, wherein the length of the line segment is 5.3 mm or more and 31.6 mm or less, and the length of the interval is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 3.5 GHz is 1 dB or more; a second combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for incident radio waves with a frequency of 3.7 GHz is 1 dB or more; a third combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for incident radio waves with a frequency of 4.5 GHz is 1 dB or more; or a fourth combination in which the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.1 mm or more and 15 mm or less, and the radio wave intensity after transmission for incident radio waves with a frequency of 4.7 GHz is 1 dB or more.

2. The radio wave transparent body according to claim 1, wherein the conductive region is a rectangle surrounded by one or more linear non-conductive regions.

3. The radio wave transmitting body according to claim 2, wherein in the first combination, the length of the line segment is 5.3 mm or more and 15.8 mm or less, the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 4 dB or more.

4. The radio wave transmitting body according to claim 3, wherein the length of the gap is 0.4 mm or more and 13 mm or less, and the radio wave intensity after transmission is 6 dB or more.

5. A radio wave transmitting body according to claim 4, wherein the length of the line segment is 6.3 mm or more and 15.8 mm or less, the length of the gap is 0.5 mm or more and 13 mm or less, and the radio wave intensity after transmission is 8 dB or more.

6. The radio wave transmitting body according to claim 2, wherein in the second combination, the length of the gap is 0.4 mm or more and 15 mm or less, and the radio wave intensity after transmission is 4 dB or more.

7. The radio wave transmitting body according to claim 6, wherein the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 6 dB or more.

8. The radio wave transmitting body according to claim 7, wherein the length of the line segment is 5.3 mm or more and 12.6 mm or less, and the radio wave intensity after transmission is 8 dB or more.

9. The radio wave transmitting body according to claim 2, wherein in the third combination, the length of the gap is 0.4 mm or more and 15 mm or less, and the radio wave intensity after transmission is 4 dB or more.

10. The radio wave transmitting body according to claim 9, wherein the length of the line segment is 5.3 mm or more and 21.1 mm or less, and the radio wave intensity after transmission is 5 dB or more.

11. A radio wave transmitting body according to claim 10, wherein the length of the line segment is 5.3 mm or more and 12.6 mm or less, the length of the gap is 0.4 mm or more and 13 mm or less, and the radio wave intensity after transmission is 6 dB or more.

12. The radio wave transmitting body according to claim 2, wherein in the fourth combination, the length of the line segment is 5.3 mm or more and 31.6 mm or less, the length of the gap is 0.4 mm or more and 14 mm or less, and the radio wave intensity after transmission is 4 dB or more.

13. The radio wave transmitting body according to claim 12, wherein the length of the gap is 0.5 mm or more and 14 mm or less, and the radio wave intensity after transmission is 5 dB or more.

14. A window material comprising: at least one transparent plate; a metal layer laminated on said at least one transparent plate; and a radio wave transparent body according to any one of claims 1 to 13 attached to said transparent plate or said metal layer.

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