Metal reflector

Abstract

To provide a radio wave reflector capable of reflecting a radio wave while securing a reflection strength, and keeping a landscape.SOLUTION: A radio wave reflector 11 contains a conductive layer 16 in which a periodic conductive pattern is formed by a liner conductor 12 and an open region 12a without the liner conductor 12 surrounded by the liner conductor 12. A ratio of an area of the open region 12a per unit area in a flat surface of a conductive layer 16 is 85% or larger. At an optional position on the conductive layer, a virtual square region S of which a length of one side is a wavelength λ of the maximum frequency of a radio wave is set, and all of the open regions that are overlapped to the square region is extracted. There is at least one square region in which a maximum value of a distance of a X direction of the open region is a maximum value Lx, a maximum value of the distance of a Y direction is a maximum value Ly, the Lx of the open region is λ / 4 or less, and a value obtained by calculating an average of an aspect ratio Ly / Lx by weighting in accordance with an area of the open region becomes larger 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a radio wave reflector for reflecting radio waves. [Background technology]

[0002] In mobile phones and wireless communications, radio waves in a frequency band of about 2 GHz to 300 GHz are used. Since such short-wavelength radio waves have a strong tendency to travel in a straight line and are difficult to bend around obstacles, reflectors are provided on the surfaces of buildings such as walls, floors, ceilings, and pillars of buildings (hereinafter referred to as "walls, etc.") in order to allow the radio waves to reach a wide range. For example, Patent Document 1 proposes a communication system in which a monopole antenna and a metal reflector that reflects radio waves are arranged in an indoor underfloor space. In Patent Document 1, the reflector diffuses the radio waves radiated from the monopole antenna into the underfloor space, and prevents the radio waves from leaking from the underfloor space to the outside of the room (building) or being absorbed by the floor of the building. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-258514 A Summary of the Invention [Problem to be solved by the invention]

[0004] Metal reflectors that reflect radio waves are generally made of metal plates such as aluminum or copper. Metal reflectors strongly reflect short-wavelength radio waves in the regular reflection direction, but are known to be difficult to diffuse and reflect radio waves, making it difficult for radio waves to reach a wide area of ​​space. Metal reflectors are generally opaque. In other words, the other side cannot be seen from one side of the metal reflector, so if such a metal reflector is used in a room, its presence is conspicuous, and if used on a window, it blocks the view, disrupting the atmosphere in the room and spoiling the view.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a radio wave reflector that can reflect radio waves while maintaining reflection strength and preserving the scenery. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention includes the subject matter described in the following paragraphs.

[0007] Section 1: A radio wave reflector for reflecting radio waves, a conductive layer having a conductive pattern formed by linear conductors and an open area surrounded by the conductors and free of the conductors; an aperture ratio, which is a ratio of an area of ​​the opening region per unit area in a plane of the conductive layer, is 85% or more; An X direction and a Y direction perpendicular to each other are arbitrarily set on the plane of the conductive layer; Assume that an incident wave of radio waves is such that the direction of a vector obtained by orthogonally projecting a vector in the vibration direction Y' of the electric field onto the conductive layer is the Y direction, and the direction of a vector obtained by orthogonally projecting a vector in the direction X' perpendicular to the vibration direction Y' of the electric field onto the conductive layer is the X direction, and the wavelength of the radio waves of the highest frequency in a predetermined frequency band of radio waves reflected by the radio wave reflector is λ, A virtual square region having a side length of λ is set at an arbitrary position on the plane of the conductive layer, All of the opening regions overlapping with the square region in the XY plane are extracted, and in each of the extracted opening regions, the maximum value of the distance between any two of the intersection points between a virtual line along the X direction and the periphery of each of the opening regions is defined as Lx, and the maximum value of the distance between any two of the intersection points between a virtual line along the Y direction and the periphery of each of the opening regions is defined as Ly; Lx of all the extracted aperture regions is λ / 4 or less, A radio wave reflector in which, when the aspect ratio of each of the extracted opening regions is Ly / Lx, there is at least one square region such that the average aspect ratio calculated by weighting the respective extracted opening regions according to their areas is greater than 1.

[0008] Section 2: Item 2. The radio wave reflector according to item 1, wherein the conductive layer has two or more opening regions with different areas.

[0009] Section 3: 3. The radio wave reflector according to item 1 or 2, wherein the ratio of the total area of ​​the extracted aperture regions having an aspect ratio greater than 1 to the total area of ​​all the aperture regions is 10% or more.

[0010] Section 4: The conductive material is provided on a surface of a substrate layer. The conductive layer is composed of the conductors parallel to the Y direction, 4. The radio wave reflector according to any one of items 1 to 3, wherein the opening region is a region surrounded by the conductor and an edge of the base layer.

[0011] Section 5: Item 5. The radio wave reflector according to any one of items 1 to 4, wherein the frequency band of radio waves reflected by the radio wave reflector is 2 GHz or more and 300 GHz or less.

[0012] Item 6: Item 6. The radio wave reflector according to any one of items 1 to 5, having a total light transmittance of 75% or more under a D65 standard light source. Effect of the Invention

[0013] According to the present invention, it is possible to provide a radio wave reflector that can reflect radio waves while maintaining reflection strength and also preserve the appearance of the scenery. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is an explanatory diagram showing an embodiment of the present invention in which a radio wave reflector reflects radio waves emitted from a transmitting antenna toward a receiving section, where (A) shows the case where the vibration direction of the electric field of the radio waves is horizontal, and (B) shows the case where the vibration direction is vertical. [Diagram 2] 1 is a cross-sectional view showing a schematic overall configuration of a radio wave reflector. [Diagram 3] 3 is a plan view showing a schematic overall configuration of the radio wave reflector shown in FIG. 2. [Figure 4] 1A and 1B are plan views for explaining the conductive pattern of Example 1, in which (A) shows a state in which a square region is set in the conductive pattern, and (B) shows an extracted opening region. [Diagram 5] 11A and 11B are plan views of a conductive pattern according to a second embodiment, in which (A) is an explanatory diagram showing a state in which a square region is set in the conductive pattern, and (B) is an explanatory diagram showing an extracted opening region. [Figure 6] 11A and 11B are plan views of a conductive pattern according to a third embodiment, in which (A) is an explanatory diagram showing a state in which a square region is set in the conductive pattern, and (B) is an explanatory diagram showing an extracted opening region. [Figure 7] 13A and 13B are plan views of a conductive pattern according to a fourth embodiment, in which (A) is an explanatory diagram showing a state in which a square region is set in the conductive pattern, and (B) is an explanatory diagram showing an extracted opening region. [Figure 8] 13A and 13B are plan views of a conductive pattern according to a fifth embodiment, in which (A) is an explanatory diagram showing a state in which a square region is set in the conductive pattern, and (B) is an explanatory diagram showing an extracted opening region. [Figure 9] 11A and 11B are plan views of the conductive pattern of Example 6, in which (A) shows a state in which a square area is set in the conductive pattern, (B) shows the extracted first opening area, and (C) shows the extracted second opening area. [Figure 10] 13A and 13B are plan views of the conductive pattern of Example 7, in which (A) shows a state in which a square region is set in the conductive pattern, and (B) shows the extracted opening region. [Figure 11]11A and 11B are plan views of the conductive pattern of Example 8, in which (A) shows a state in which a square area is set in the conductive pattern, (B) shows the extracted first opening area, and (C) shows the extracted second opening area. [Figure 12] 13A and 13B are plan views of the conductive pattern of Example 9, in which (A) shows a state in which a square area is set in the conductive pattern, (B) shows the extracted first opening area, and (C) shows the extracted second opening area. [Figure 13] 13A and 13B are plan views of the conductive pattern of Example 10, in which (A) shows a state in which a square area is set in the conductive pattern, (B) shows the extracted first opening area, and (C) shows the extracted second opening area. [Figure 14] 6(A) to 6(D) are explanatory views showing other examples of the conductive pattern. [Figure 15] FIG. 11 is a cross-sectional view showing another embodiment of a radio wave reflector. [Figure 16] FIG. 11 is a cross-sectional view showing another embodiment of a radio wave reflector. [Figure 17] (A) is an explanatory diagram showing an example of indoor application of building materials, and (B) is a plan view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Overall composition) An embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1(A) and Fig. 1(B), the radio wave reflector 11 of the present invention reflects radio waves output from a transmitting antenna 20 of a radio wave source, and the reflected waves are received by a receiving unit 21. The radio wave source is a communication device having a transmitting antenna 20 capable of transmitting radio waves. The receiving unit 21 is a communication device having a receiving antenna capable of receiving radio waves. Examples of the receiving unit 21 include a smartphone, a mobile phone, a tablet terminal, a notebook PC, a portable game machine, a repeater, a radio, and a television. Note that Fig. 1 is described for the purpose of explanation, and does not show the actual radio wave reflector 11, the transmitting antenna 20, and the receiving unit 21, and does not show the actual incident wave, reflected wave, and reflection angle.

[0016] The frequency band of the radio wave (incident wave) reflected by the radio wave reflector 11 is 2 GHz or more and 300 GHz or less, and preferably, radio waves in any frequency band of 2 GHz or more and less than 6 GHz, 6 GHz or more and less than 20 GHz, 20 GHz or more and less than 60 GHz, 60 GHz or more and less than 100 GHz, 100 GHz or more and less than 150 GHz, or 150 GHz or more and 300 GHz or less are reflected by the radio wave reflector 11. The incident angle of the incident wave is at least a certain angle of 15 degrees or more and 75 degrees or less, and is preferably 45 degrees, and more preferably the entire range of angles of 15 degrees or more and 75 degrees or less.

[0017] The radio wave reflector 11 has a total light transmittance of 75% or more under the D65 standard light source, preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The total light transmittance refers to the ratio of the total transmitted light flux to the parallel incident light flux of the test piece, and is specified in JISK7375:2008. That is, the radio wave reflector 11 is so-called "transparent", and "transparent" means that the other side of the radio wave reflector 11 can be seen from one side of the radio wave reflector 11, and includes translucency. The radio wave reflector 11 may be colored as a whole. In addition, as will be described in detail later, when the radio wave reflector 11 includes the conductive layer 16 including the conductor 12, the base layer 13, the adhesive layer 14, and the protective layer 15, each layer may be formed of a resin having a total light transmittance of 75% or more, and the conductor 12 of the conductive layer 16 may be formed to a thickness having a total light transmittance of 75% or more.

[0018] In the present embodiment, the radio wave reflector 11 has a square overall shape in a plane, and the length L10 of one side is preferably 15 cm or more and 400 cm or less. Radio waves with frequencies of 2 GHz or more and 300 GHz or less attenuate with distance, but in order to reflect the radio waves with sufficient strength at all points within a practical distance from the transmitting antenna 20, the length L10 of one side is preferably 15 cm or more. There is no particular upper limit to the length L10 of one side, but from the viewpoint of manufacturing, it is preferably 400 cm or less. The overall shape is not limited to a square, and may be a rectangle, or a polygon such as a triangle, a pentagon, or a hexagon. In this case, the length of the shortest side is set to 15 cm or more and 400 cm or less. Alternatively, the shortest distance between a certain vertex and the opposite side, or the shortest distance between a certain side and the opposite side may be set to 15 cm or more and 400 cm or less. In addition, when the overall shape of the radio wave reflector 11 is a circle, the diameter is set to 15 cm or more and 400 cm or less. When the overall shape of the radio wave reflector 11 is elliptical, the minor axis is set to 15 cm or more and 400 cm or less. When the overall shape of the radio wave reflector 11 is sector-shaped, the shorter length of the arc or radius is set to 15 cm or more and 400 cm or less. Furthermore, the overall shape may be a three-dimensional shape such as a cylindrical or conical shape. The overall shape and size of the radio wave reflector 11 are such that the radio wave can be reflected with a reflection strength of -30 dB or more relative to the incident wave, and the shape and size are appropriately selected depending on the manner in which the radio wave reflector 11 is used.

[0019] In this embodiment, the radio wave reflector 11 has a thickness L1 of about 0.25 mm, but is not limited thereto, and the thickness L1 is preferably 1 mm or less. When the radio wave reflector 11 includes the conductive layer 16, the base layer 13, the adhesive layer 14, and the protective layer 15 as described below, the thicknesses of the base layer 13, the conductive layer 16, the adhesive layer 14, and the protective layer 15 are set so that the thickness L1 of the radio wave reflector 11 is 1 mm or less. The thickness L1 of the radio wave reflector 11 is the sum of the thickness L3 of the conductive layer 16 and the thickness L2 of the base layer 13, or the sum of the thickness L3 of the conductive layer 16, the thickness L2 of the base layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15. However, since the thickness L3 of the conductive layer 16 is much thinner than the thicknesses L2, L4, and L5 of the base layer 13, the adhesive layer 14, and the protective layer 15, the thickness L3 of the conductive layer 16 may be ignored when calculating the thickness L1 of the radio wave reflector 11. Furthermore, the thickness L1 of the radio wave reflector 11, the thickness L3 of the conductive layer 16, the thickness L2 of the base layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15 are determined by measuring any two or more locations and calculating the average value of the obtained measured values. For example, a reflectance spectroscopic film thickness measurement (e.g., F3-CS-NIR, manufactured by Filmetrics Inc.) is used as a measuring instrument to measure the thickness L1, the thickness L3, the thickness L2, the thickness L4, and the thickness L5.

[0020] The radio wave reflector 11 may have plasticity. Plasticity refers to a property that allows deformation by application of external pressure, and when deformation beyond the elastic limit is caused by pressure, the deformed shape is maintained even after the force is removed. All of the synthetic resins constituting the base layer 13, the adhesive layer 14, and the protective layer 15 may have plasticity, or at least one of the base layer 13, the adhesive layer 14, and the protective layer 15 may have plasticity.

[0021] (Structure of radio wave reflector 11) An example of the structure of the radio wave reflector 11 will be described with reference to Figs. 2 and 3. The radio wave reflector 11 may have a conductive layer 16 including a conductor 12, a base material layer 13 laminated on the conductive layer 16 and including a base material, a protective layer 15 including a protective material for protecting the conductive layer 16, and an adhesive layer 14 including an adhesive for bonding the conductive layer 16 and the protective layer 15. The radio wave reflector 11 may also have the conductive layer 16 including the conductor 12 and a resin for keeping the conductor 12 in a sheet shape. At least one of the base material layer 13 including a base material, the protective layer 15 including a protective material for protecting the conductive layer 16, and the adhesive layer 14 including an adhesive for bonding the conductive layer 16 and the protective layer 15 may be made of a resin. In Fig. 2, the radio wave reflector 11 is laminated in the order of the base material layer 13, the conductive layer 16, the adhesive layer 14, and the protective layer 15 from the bottom.

[0022] In the following description, the up-down direction is defined based on Fig. 2, but the up-down direction is used for the purpose of explanation and does not define the actual up-down direction when the radio wave reflector 11 is used, such as when it is attached to a building or the like. Also, Figs. 1 to 17 do not show the actual scale. Also, in Fig. 3, the adhesive layer 14 and protective layer 15 are omitted from the illustration in part of the radio wave reflector 11.

[0023] (Base material layer 13) The base layer 13 is made of a base material, and has a conductive layer 16 including a conductor 12 laminated on the upper surface. In this embodiment, the outer shape is formed in a square shape in a plane, but is not limited thereto, and may be a rectangle, a circle, an ellipse, a sector, a polygon, a three-dimensional shape, or the like according to the overall shape of the radio wave reflector 11. A synthetic resin sheet is used as the base material, which is the base material layer 13. 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. In this embodiment, the thickness L2 of the base material layer 13 (the length in the vertical direction in FIG. 2) is set to 50 μm, but is not limited thereto. In addition to the base material, the base material layer 13 may contain any substance such as a synthetic resin or any other material.

[0024] (Conductive layer 16) The conductive layer 16 is preferably a layer in which one or more linear conductors 12 are formed as a thin film on the upper surface of the base layer 13. The conductors 12 are preferably made of, for example, silver (Ag). The conductors 12 may be made of any metal having free electrons, and are not limited to silver. For example, the conductors 12 may be gold (Au), copper (Cu), platinum (Pt), zinc (Zn), iron (Fe), tin (Sn), lead (Pb), aluminum (Al), cobalt (Co), indium (In), nickel (Ni), chromium (Cr), titanium (Ti), aluminium (Sb), bismuth (Bi), thallium (Tl), germanium (Ge), cadmium (Cd), silicon (Si), tungsten (W), molybdenum (Mo), indium tin oxide (ITO), and alloys (for example, 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, X, etc.

[0025] In addition, the thickness (film thickness) L3 of the conductive layer 16 (conductor 12) is set to 500 nm (0.5 μm) or less in this embodiment, but is not limited to this. From the viewpoint of ensuring appropriate radio wave intensity, the thickness L3 is preferably 5 nm or more. Note that the conductive layer 16 may contain, in addition to the conductor 12, any substance such as a synthetic resin or any other material.

[0026] The conductive layer 16 includes a periodic conductive pattern formed by linear conductors 12 and opening regions 12a surrounded by the conductors 12 and having no conductors 12. That is, the conductors 12 and the opening regions 12a are arranged at a predetermined interval. The conductors 12 and the opening regions 12a may be arranged periodically. The conductors 12 and the opening regions 12a gather together to form a thin film. The term "linear" means that the length in the longitudinal direction is 3000 times or more the length in the direction perpendicular to the longitudinal direction. The line width L6 of the conductors 12 is set to 0.1 μm or more and 10 μm or less. An example of the conductive pattern is shown in region A of FIG. 3 and in FIGS. 4 to 13 and 14. The details of the example of the conductive pattern will be described later.

[0027] The conductive pattern is formed so as to satisfy the following conditions.

[0028] The conductive pattern is formed so that the opening ratio, which is the ratio of the area of ​​the open regions 12a per unit area on the plane of the conductive layer 16, is 85% or more.

[0029] The conductive pattern is formed to satisfy the following conditions. An X direction and a Y direction perpendicular to each other are arbitrarily set on the plane of the conductive layer 16. The vibration direction of the electric field of the incident wave of the radio wave is the Y' direction (also called the "vibration direction Y'"), and the direction perpendicular to the vibration direction of the electric field of the incident wave of the radio wave is the X' direction (also called the "direction X'"). The vibration direction of the electric field of the radio wave is the direction in which the amplitude of the electric field changes on the X'Y' plane perpendicular to the Z direction of the radio wave. The incident radio wave is assumed such that the direction of the vector obtained by orthogonally projecting the vector of the vibration direction Y' of the electric field onto the conductive layer 16 is the Y direction (also called the "orthogonal projection direction Y of the vibration direction of the electric field"), and the direction of the vector obtained by orthogonally projecting the vector of the direction X' onto the conductive layer 16 is the X direction. The wavelength of the radio wave of the highest frequency in a predetermined frequency band of radio waves reflected by the radio wave reflector 11 is λ.

[0030] In FIG. 1(A), the transmitting antenna 20 has a rectangular opening, and the length of the opening is aligned along the vertical direction. In this case, the vibration direction Y' of the electric field of the radio wave is the horizontal direction, which is perpendicular to the vertical direction, and the radio wave is called a horizontally polarized wave. In FIG. 1(B), the transmitting antenna 20 has a rectangular opening, and the length of the opening is aligned along the horizontal direction, which is perpendicular to the vertical direction. In this case, the vibration direction Y' of the electric field of the radio wave is the vertical direction, and the radio wave is called a vertically polarized wave. Note that the vibration direction Y' of the electric field of the radio wave can be set in any direction, not limited to the above example.

[0031] 1(A) and (B), the radio waves are incident so that the traveling direction Z of the radio waves is perpendicular to the surface of the conductive layer 16 of the radio wave reflector 11, and the vibration direction Y' of the electric field of the radio waves coincides with the Y direction, and the X' direction coincides with the X direction. The conductive layer 16 being parallel to the XY plane means that the upper surface of the base layer 13 on which the conductor 12 is formed is parallel to the XY plane, and the plane of the conductive layer 16 means a surface that includes a conductive pattern and is parallel to the upper surface of the base layer 13 on which the conductor 12 is formed. Note that the traveling direction Z of the radio waves does not necessarily need to be perpendicular to the surface of the conductive layer 16 of the radio wave reflector 11, and the radio waves may be incident on the surface of the conductive layer 16 by traveling in a direction deviated from the direction perpendicular to the surface of the conductive layer 16.

[0032] A virtual square region S with a side length of λ is set at an arbitrary position on the surface of the conductive layer 16. All opening regions 12a overlapping with the square region S in the XY plane are extracted. In each of the extracted opening regions 12a, the maximum value of the distance between any two of the intersection points between a virtual line AX (FIG. 3) along the X direction and the periphery of each opening region is set as Lx. Also, the maximum value of the distance between any two of the intersection points between a virtual line AY (FIG. 3) along the Y direction and the periphery of each opening region 12a is set as Lx. At this time, Lx of all the extracted opening regions 12a is λ / 4 or less. When the aspect ratio of each extracted opening region 12a is set as Ly / Lx, there is at least one square region S whose average aspect ratio is greater than 1 when weighted according to the area of ​​each extracted opening region 12a.

[0033] The length of one side of the square area S is set to the wavelength λ of the radio wave of the highest frequency incident on the radio wave reflector 11 in order to ensure the minimum size of the square area S required to calculate the reflection loss of the radio wave reflector 11 in, for example, the simulation software ANSYS HFSS. By setting the length of one side of the square area S to the wavelength λ of the radio wave, a sufficient size of the square area S can be ensured for the first Fresnel radius in the evaluation conditions for the reflection loss. The first Fresnel radius is an index indicating the spread of radio waves between the so-called transmitting and receiving antennas, and is defined by the frequency of the radio waves and the distance between the transmitting and receiving antennas and the radio wave reflector. If the size of the square area S is equal to or larger than the first Fresnel radius, it is considered that the strength of the radio waves received by the receiving antenna (receiving unit 21) will be approximately the same regardless of the size of the radio wave reflector 11. The reflection loss is calculated using the above simulation software for the square area S or an area including the square area S but larger than the square area S.

[0034] Furthermore, Lx is set to λ / 4 or less because as Lx increases, reflection loss increases, and the receiver 21 is unable to receive the reflected wave with sufficient strength when the radio wave reflector 11 reflects the radio wave. By setting Lx to λ / 4 or less, the reflection loss becomes 2 dB or less, and the receiver 21 can receive radio waves with a strength that is suitable for practical use.

[0035] The conductive layer preferably has two or more types of open regions 12a (12c, 12d, 12e, 12f) with different areas.

[0036] It is preferable that the ratio (area ratio) of the total area of ​​the opening regions 12a having an aspect ratio greater than 1 to the total area of ​​all the extracted opening regions 12a is 10% or more.

[0037] Reflection of radio waves occurs when a surface current flows on the reflecting surface of the radio wave reflector 11 in a direction parallel to the orthogonal projection direction Y of the vibration direction of the electric field due to the incident electric field, and the energy of the current is re-radiated into the atmosphere. Therefore, the reflection loss of radio waves is smaller as the surface current flows more easily, and the smaller the reflection loss, the greater the intensity of radio waves reflected by the radio wave reflector 11. As described above, since the average value of the aspect ratio Ly / Lx of the opening region 12a is greater than 1, the length of the opening region 12a in the Y direction is longer than the X direction, and the length of the conductor 12 surrounding the opening region 12a in the Y direction is longer than the X direction. Therefore, a surface current flows easily in the conductor 12 aligned along the Y direction, and reflection loss is likely to be reduced.

[0038] (adhesive layer 14) The adhesive layer 14 is for bonding the protective layer 15 onto the base material layer 13 and the conductive layer 16, and is made of an adhesive. The adhesive layer 14 has a size corresponding to the base material layer 13 in a plane. An adhesive sheet made of synthetic resin or rubber is used as the adhesive of the adhesive layer 14. Examples of synthetic resin include acrylic resin, silicone resin, polyvinyl alcohol resin, etc. In this embodiment, the thickness L4 of the adhesive layer 14 is set to 150 μm, but is not limited to this. The adhesive layer 14 may contain any substance such as a synthetic resin or any member in addition to the adhesive.

[0039] It is preferable that the adhesive layer 14 does not contain an ultraviolet absorbing agent. If the adhesive layer 14 does not contain an ultraviolet absorbing agent, there is an advantage that the adhesive layer 14 can be easily adjusted to be colorless and transparent. Here, "not containing" includes not only the case where the adhesive layer 14 does not contain any ultraviolet absorbing agent, but also the case where the adhesive layer 14 contains a small amount of ultraviolet absorbing agent that does not impair the colorless and transparent properties.

[0040] (Protective layer 15) The protective layer 15 has a size corresponding to the base layer 13 in a plane, protects the conductor 12, and is made of a protective material. A synthetic resin film is used as the protective material of the protective layer 15. 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. The thickness L5 of the protective layer 15 is set to 50 μm in this embodiment, but is not limited to this. The protective layer 15 may contain any substance such as a synthetic resin or any member in addition to the protective material.

[0041] (Example) Examples 1 to 10 were prepared as the radio wave reflector 11 of the present invention. Examples 1 to 10 have different conductive patterns of the conductive layer 16. The conductive patterns of Examples 1 to 10 are described below. However, the radio wave reflector 11 of the present invention is not limited to Examples 1 to 10. Also, Figs. 4 to 13 are enlarged views of a part of the radio wave reflector 11 for explaining the conductive pattern, and are plan views of the conductor 12 provided on the base layer 13. The adhesive layer 14 and the protective layer 15 are omitted in Figs. 4 to 13. Note that the drawings are used to explain the radio wave reflector 11, and the dimensions and dimensional ratios in the drawings do not indicate the actual dimensions and dimensional ratios.

[0042] Example 1 As shown in FIG. 4(A), the conductive pattern of the first embodiment includes a plurality of conductors 12A arranged along one direction Y1 (horizontal direction in FIG. 4). The distance L7 between adjacent conductors 12A is constant. In this example, the conductors 12A extend to the edges 13a on both sides of the base layer 13, and the opening region 12a is defined as a region surrounded by the conductors 12A and the edges 13a of the base layer 13. In other words, the opening regions 12a are arranged at intervals of the line width L6 of the conductors 12A. In the first embodiment, each opening region 12a has the same rectangular shape, and the length direction is along the one direction Y1 and the width direction is along the direction X1 perpendicular to the one direction Y1. In the following description, the one direction Y1 and the direction X1 perpendicular to the one direction are also referred to as the length direction Y1 and the width direction X1 of the opening region 12a, respectively.

[0043] 3, the conductive layer 16 is not provided on the peripheral portion of the base layer 13, but is provided inside the edge 13a of the base layer 13. In such a case, the opening region 12a is defined as a rectangle whose length in the longitudinal direction Y1 is equal to the length of the conductor 12A in the longitudinal direction and whose length in the width direction X1 is equal to the distance L7 between adjacent conductors 12A.

[0044] In the first embodiment, the line width L6 is set to 0.01 mm, and the distance L7 between adjacent conductors 12A is set to 0.1 mm. The rectangular opening region 12a of the conductive pattern has a length in the length direction Y1 (equal to the length L10 of one side of the radio wave reflection pair 11) of 32 mm and a length in the width direction X1 of 0.10 mm, and the area of ​​each opening region 12a is 3.2 mm. 2 (square millimeters).

[0045] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is preferably 85% or more, and is 91% in Example 1. The aperture ratio can also be said to be the ratio of the area of ​​the base layer 13 not covered by the conductor 12 to a unit area in the plane of the base layer 13. When the conductive layer 16 is not provided on the peripheral portion of the base layer 13 but is provided inside the edge 13a of the base layer 13 as in the embodiment shown in FIG. 3, the aperture ratio refers to the ratio of the area of ​​the open regions 12a per unit area in the region on the upper surface of the base layer 13 where the conductive layer 16 is provided in the plane. The region where the conductive layer 16 is provided is the region of the upper surface region of the base layer 13 excluding the peripheral portion of the base layer 13 (the portion between the edge 13a of the base layer 13 and the conductive layer 16). The aperture ratio is measured using a scanning electron microscope (SEM), a transmission electron microscope (TEM), an optical microscope, or the like.

[0046] Let λ be the wavelength of the radio wave of the highest frequency in a predetermined frequency band of radio waves reflected by the radio wave reflector 11. In this embodiment, the frequency band is preferably from 2 GHz to 300 GHz, in which case the highest frequency is 300 GHz and the wavelength λ is 1 mm.

[0047] With the surface of the conductive layer 16 parallel to the XY plane, as shown in Fig. 4(A), a virtual square region S with a side length of λ is set at an arbitrary position on the plane of the conductive layer 16. In the example of Fig. 4, the sides of the square region S are set along the X and Y directions, and the conductive layer 16 is set so that the length direction Y1 (one direction, the horizontal direction in Fig. 4) of the rectangular opening region 12a is aligned along the Y direction, and the width direction X1 of the opening region 12a is aligned along the X direction.

[0048] Then, all the opening regions 12a that overlap even a part of the square region S in the XY plane are extracted. In this example, as shown in FIG. 4(B), ten opening regions 12a are extracted. In FIG. 4(B), the extracted opening regions 12a are shown by being filled in. As described above, FIG. 4 is an enlarged view of a part of the radio wave reflector 11, and the actual length of the opening region 12a in the longitudinal direction Y1 (maximum Y-direction value Ly, described later) is equal to the length L10 of one side of the radio wave reflector 11.

[0049] In each of the extracted opening regions 12a, the maximum value of the distance between any two of the intersection points of the virtual line AX along the X direction and the periphery of each opening region 12a is set as the X-direction maximum value Lx, and the maximum value of the distance between any two of the intersection points of the virtual line AY along the Y direction and the periphery of each opening region 12a is set as the Y-direction maximum value Ly (FIG. 3(B)). In this example, the virtual line AX along the X direction extends along the width direction X1 (direction perpendicular to one direction) of the rectangular opening region 12a, and the length in the width direction of the opening region 12a is the X-direction maximum value Lx. In addition, the virtual line AY along the Y direction extends along the length direction Y1 of the opening region 12a, and the length in the length direction Y1 of the opening region 12a, i.e., the length L10 of one side of the radio wave reflecting pair, is the Y-direction maximum value Ly.

[0050] At this time, the maximum value Lx in the X direction of all the extracted opening regions 12a is equal to or smaller than λ / 4. The aspect ratio of the extracted opening regions is defined as Ly / Lx, and the average aspect ratio is calculated by weighting according to the area of ​​the extracted opening regions 12a. At this time, the average aspect ratio is greater than 1. The conductive pattern is provided so that there is at least one such square region S.

[0051] In this example, the extracted opening regions 12a are rectangular and have the same area and shape, so the extracted opening regions 12a are weighted equally and have an average aspect ratio of 32.

[0052] It is also preferable that the total area of ​​the opening regions having an aspect ratio greater than 1 is 10% or more of the total area of ​​all the extracted opening regions 12a. In Example 1, since the aspect ratio of all the extracted opening regions 12a is greater than 1, the area ratio, which is the ratio of the total area of ​​the opening regions having an aspect ratio greater than 1 to the total area of ​​all the extracted opening regions 12a, is 100%.

[0053] The installation method of the radio wave reflector 11 of the first embodiment is as follows. The radio wave reflector 11 reflects radio waves transmitted from a fixedly installed transmitting antenna 20, and the vibration direction Y' of the electric field of the radio waves reflected by the radio wave reflector 11 and the direction X' perpendicular to the vibration direction Y' are known, and the angle at which the traveling direction Z of the radio waves is incident on the surface of the conductive layer 16 of the radio wave reflector 11 is also known, so that the orthogonal projection direction Y of the vibration direction of the electric field and the X direction perpendicular to the Y direction are also known. The above-mentioned square area S is set on the surface of the conductive layer 16, and the radio wave reflector 11 is installed on the installation target so that it is aligned with the Y direction used to calculate the average aspect ratio and the length direction Y1 (one direction) of the opening area 12a of the radio wave reflector 11. In Fig. 1(A), the vibration direction Y' of the radio wave and the orthogonal projection direction Y of the vibration direction of the electric field are along the horizontal direction, so the radio wave reflector 11 is provided so that the length direction Y1 (one direction) of the rectangular opening region 12a is along the horizontal direction. In Fig. 1(B), the vibration direction Y' of the radio wave and the orthogonal projection direction Y of the vibration direction of the electric field are along the vertical direction, so the radio wave reflector 11 is provided so that the length direction Y1 (one direction) of the opening region 12a of Example 1 is along the vertical direction. Note that in Fig. 1, a part of the opening region 12a of the radio wave reflector 11 is shown enlarged for the purpose of explanation.

[0054] Example 2 In the following description of the second embodiment, only the differences from the first embodiment will be described, and the same configurations and settings as those of the first embodiment will be omitted. In the second embodiment, as shown in FIG. 5(A), the conductor 12 includes a conductor 12A along one direction Y1 and a conductor 12B along a direction X1 perpendicular to the one direction. The opening region 12a surrounded by the conductors 12A and 12B is rectangular. The distance L7 between the conductors 12A adjacent to each other along the one direction Y1 and the distance L8 between the conductors 12B adjacent to each other along the direction X1 perpendicular to the one direction are constant, and the distance L7 between the conductors 12A is shorter than the distance L8 between the conductors 12B adjacent to each other. The conductors 12A and 12B are conductive at the intersections where the conductors 12A and 12B overlap.

[0055] In the second embodiment, the distance L8 between adjacent conductors 12B, i.e., the length L8 in the longitudinal direction Y1 (one direction, the horizontal direction in FIG. 5) of the rectangular opening region 12a, is 1.0 mm, and the distance L7 between adjacent conductors 12A, i.e., the length L7 in the width direction X1 of the rectangular opening region 12a, is 0.11 mm. The area of ​​each opening region 12a is 0.11 mm. 2 (square millimeters).

[0056] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is 91%.

[0057] As shown in Fig. 5(A), a virtual square region S is set on the conductive layer 16. As shown in Fig. 5(B), nine opening regions 12a are extracted that overlap at least partially with the square region S in the XY plane. The extracted opening regions 12a are all rectangular and have the same size and area.

[0058] In Example 2, the maximum X-direction value Lx of all the extracted opening regions 12a is equal to or less than λ / 4. Since the extracted opening regions 12a have the same area and rectangular shape, the extracted opening regions 12a are weighted equally, and the average aspect ratio is 9.1.

[0059] Example 3 In the following description of the third embodiment, only the points different from the second embodiment will be described, and a description of the same configurations and settings as the second embodiment will be omitted.

[0060] In the third embodiment, the distance L8 between adjacent conductors 12B, i.e., the length L8 in the longitudinal direction Y1 of the rectangular opening region 12a, is 0.52 mm, and the distance L7 between adjacent conductors 12A, i.e., the length L7 in the transverse direction X1 of the rectangular opening region 12a, is 0.12 mm. The area of ​​each opening region 12a is 0.062 mm. 2 (square millimeters).

[0061] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is 91%.

[0062] As shown in Fig. 6(A), a virtual square region S is set on the conductive layer 16. As shown in Fig. 6(B), 16 opening regions 12a are extracted that overlap at least partially with the square region S in the XY plane. The extracted opening regions 12a are all rectangular and have the same size and area.

[0063] In Example 3, the maximum X-direction value Lx of all the extracted opening regions 12a is equal to or less than λ / 4. Since the extracted opening regions 12a have the same area and the same rectangular shape, the extracted opening regions 12a are weighted equally, and the average aspect ratio is 4.3.

[0064] Example 4 In the following description of the fourth embodiment, only the points different from the second embodiment will be described, and a description of the same configurations and settings as the second embodiment will be omitted.

[0065] In the fourth embodiment, the distance L8 between adjacent conductors 12B, i.e., the length L8 in the longitudinal direction Y1 of the rectangular opening region 12a, is 0.34 mm, and the distance L7 between adjacent conductors 12A, i.e., the length L7 in the transverse direction X1 of the rectangular opening region 12a, is 0.14 mm. The area of ​​each opening region 12a is 0.048 mm. 2 (square millimeters).

[0066] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is 91%.

[0067] As shown in Fig. 7(A), a virtual square region S is set on the conductive layer 16. As shown in Fig. 7(B), 21 opening regions 12a that overlap at least partially with the square region S in the XY plane are extracted. The extracted opening regions 12a are all rectangular and have the same size and area.

[0068] In Example 4, the maximum X-direction value Lx of all the extracted opening regions 12a is equal to or less than λ / 4. Since the extracted opening regions 12a have the same area and rectangular shape, the extracted opening regions 12a are weighted equally, and the average aspect ratio is 2.4.

[0069] Example 5 In the following description of the fifth embodiment, only the points different from the second embodiment will be described, and the description of the same configurations and settings as the second embodiment will be omitted.

[0070] In the fifth embodiment, the distance L8 between adjacent conductors 12B, i.e., the length L8 in the longitudinal direction Y1 of the rectangular opening region 12a, is 0.22 mm, and the distance L7 between adjacent conductors 12A, i.e., the length L7 in the transverse direction X1 of the rectangular opening region 12a, is 0.19 mm. The area of ​​each opening region 12a is 0.042 mm 2 (square millimeters).

[0071] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is 91%.

[0072] As shown in Fig. 8(A), a virtual square region S is set on the surface of conductive layer 16 parallel to the XY plane. As shown in Fig. 8(B), 24 opening regions 12a that overlap at least partially with square region S are extracted in the XY plane. All of the extracted opening regions 12a are rectangular and have the same size and area.

[0073] In Example 5, the maximum X-direction value Lx of all the extracted opening regions 12a is equal to or less than λ / 4. Since the extracted opening regions 12a have the same area and rectangular shape, the extracted opening regions 12a are weighted equally and have an average aspect ratio of 1.2.

[0074] Example 6 In the following description of the sixth embodiment, only the differences from the first embodiment will be described, and the same configurations and settings as those of the first embodiment will be omitted. The opening region 12a includes opening regions 12c and 12d that are free of a plurality (two or more) of types of conductors 12 with different areas. In the region 40 of the conductive layer 16, the conductors 12 include the conductors 12A along one direction Y1 and the conductors 12B along the direction X1 perpendicular to the one direction, and have a square-shaped first opening region 12c surrounded by the conductors 12A and 12B. The distance L41 between the adjacent conductors 12A and the distance L40 between the adjacent conductors 12B are equal. In the region 41 that is provided continuously in the region 40 along the direction X1 perpendicular to the one direction, the conductors 12 include the conductors 12A along one direction Y1 and the conductors 12B along the direction X1 perpendicular to the one direction, and have a rectangular second opening region 12d surrounded by the conductors 12A and 12B. A distance L43 between adjacent conductors 12A is shorter than a distance L42 between adjacent vertical conductors 12B. The number of conductors 12B in region 41 is smaller than the number of conductors 12B in region 40, and the conductors 12B in region 41 are continuous with the conductors 12B in region 40. Regions 40 and 41 are alternately arranged along a direction X1 perpendicular to one direction.

[0075] In the sixth embodiment, in the first opening region 12c, the distance L41 between adjacent conductors 12A and the distance L40 between adjacent conductors 12B, i.e., the length of one side of the square first opening region 12c, is set to 0.20 mm, and the area of ​​each first opening region 12c is 0.040 mm. 2In the second opening region 12d, the distance L42 between adjacent conductors 12B, i.e., the length L42 in the longitudinal direction Y1 of the rectangular opening region 12a, is 1.0 mm, and the distance L43 between adjacent conductors 12A, i.e., the length L43 in the width direction X1 of the rectangular opening region 12a, is 0.1 mm. The area of ​​each opening region 12d is 0.10 mm 2 (square millimeters).

[0076] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the first opening region 12c and the second opening region 12d per unit area, is 91%.

[0077] 9(A), a virtual square region S with a side length of λ is set at an arbitrary position on the surface of conductive layer 16 parallel to the XY plane. In this example, the width direction X1 of rectangular opening region 12d is aligned along the X direction, and the length direction Y1 of opening region 12d (one direction, the horizontal direction in FIG. 9) is aligned along the Y direction.

[0078] Then, all the opening regions 12a that overlap even a part of the square region S in the XY plane are extracted. In this example, 20 opening regions 12c are extracted as shown in Fig. 9(B). Furthermore, two opening regions 12d are extracted as shown in Fig. 9(C).

[0079] In each of the first and second opening regions 12c and 12d having different areas, the maximum value of the distance between any two of the intersection points between the virtual line AX along the X direction and the periphery of each of the first and second opening regions 12c and 12d is set as the X-direction maximum value Lx. In addition, the maximum value of the distance between any two of the intersection points between the virtual line AY along the Y direction and the periphery of each opening region 12a is set as the Y-direction maximum value Ly. In this example, in the first opening region 12c, the X-direction maximum value Lx and the Y-direction maximum value Ly correspond to the length of one side of the square shape, which is 0.2 mm. In the second opening region 12d, the X-direction maximum value Lx corresponds to the length L43 of the rectangular shape in the width direction X1 (direction perpendicular to one direction), and the Y-direction maximum value Ly corresponds to the length L42 (length along one direction) of the rectangular shape in the length direction Y1, where the X-direction maximum value Lx is 0.1 mm and the Y-direction maximum value Ly is 1.0 mm.

[0080] In this case, the maximum value Lx in the X direction of all the extracted first opening regions 12c and all the extracted second opening regions 12f is λ / 4 or less. The aspect ratio of each of the extracted first and second opening regions 12c and 12d is defined as Ly / Lx, and the average aspect ratio is calculated by weighting according to the area of ​​each of the extracted first and second opening regions 12c and 12d. Specifically, the average aspect ratio is calculated using the following formula 1.

[0081] Average aspect ratio = aspect ratio of the first opening region × (total area of ​​the extracted first opening region / total area of ​​the extracted first and second opening regions) + aspect ratio of the second opening region × (total area of ​​the extracted second opening region / total area of ​​the extracted first and second opening regions) (Formula 1)

[0082] Where: Sum of the areas of the extracted first opening regions = area of ​​each first opening region x number of extracted first opening regions, Sum of the areas of the extracted second opening regions = area of ​​each second opening region x number of extracted second opening regions; The sum of the areas of the extracted first and second opening regions = the sum of the areas of the extracted first opening regions + the sum of the areas of the extracted second opening regions, It is.

[0083] In this case, there is at least one square region S in which the average value of the aspect ratio is greater than 1. The conductive pattern is provided so that the square region S having such an average aspect ratio can be set.

[0084] In this example, since the extracted first and second opening regions 12c and 12d have different areas, opening regions 12c and 12d are weighted according to the area of ​​each opening region 12c and 12d as shown in Equation 1 to calculate the average aspect ratio, which is 2.8.

[0085] It is also preferable that the area ratio of the total area of ​​opening region 12d, which has an aspect ratio greater than 1, is 10% or more relative to the total area of ​​the extracted first and second opening regions. In Example 6, the aspect ratio of opening region 12c is 1, but the aspect ratio of opening region 12d is greater than 1. In Example 6, the total area ratio of the extracted first and second opening regions, which is 1 mm 2 The total area of ​​the extracted second opening regions is 0.2 mm 2 and the area ratio is 20%.

[0086] Example 7 In the following description of the seventh embodiment, only the differences from the first embodiment will be described, and a description of the same configurations and settings as those in the first embodiment will be omitted.

[0087] In the seventh embodiment, the line width L6 is set to 0.002 mm, and the distance L7 between adjacent conductors 12A is set to 0.11 mm. The length of the rectangular opening region 12a in the longitudinal direction Y1 (equal to the length L10 of one side of the radio wave reflector 11) is 32 mm, the length of the rectangular opening region 12a in the width direction X1 is 0.11 mm, and the area of ​​each opening region 12a is 0.35 mm. 2 10 showing the seventh embodiment is an enlarged view of a part of the radio wave reflector 11, and the actual length of the opening region 12a in the longitudinal direction Y1 (maximum value Ly in the Y direction) is equal to the length L10 of one side of the radio wave reflector 11.

[0088] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the open regions 12a per unit area, is 98%.

[0089] As shown in Fig. 10(A), a virtual square region S is set on the conductive layer 16. As shown in Fig. 10(B), eleven opening regions 12a are extracted that overlap at least partially with the square region S in the XY plane. All of the extracted opening regions 12a are rectangular and have the same size and area.

[0090] In Example 7, the maximum X-direction value Lx of all the extracted opening regions 12a is equal to or less than λ / 4. Since the extracted opening regions 12a have the same area and the same rectangular shape, the extracted opening regions 12a are equally weighted and have an average aspect ratio of 29.

[0091] Example 8 In the following description of the eighth embodiment, only the points different from the sixth embodiment will be described, and the description of the same configurations and settings as those of the sixth embodiment will be omitted.

[0092] In the eighth embodiment, the conductor pattern has an ellipse with the conductors 12 continuing, the long axis of the ellipse is along one direction Y1, and the short axis is along the direction X1 perpendicular to the one direction. As shown in FIG. 11(A), the vertices of the ellipse shapes adjacent to each other along the one direction Y1 and the direction X1 perpendicular to the one direction overlap and are conductive. The opening region 12a includes a first opening region 12e and a second opening region 12f having different areas and free of a plurality (two) types of conductors 12. The shape of the region 12e free of the conductors 12 is an ellipse, and the shape of the region 12f free of the conductors 12 is a rectangle with sides curved inward. The line width L6 of the conductors 12 is 0.002 mm.

[0093] In the eighth embodiment, as shown in FIG. 11B, in the first opening region 12e, the length L44 of the major axis of the ellipse along one direction Y1 is set to 1.0 mm, the length L45 of the minor axis along the direction X1 perpendicular to the one direction is set to 0.11 mm, and the area of ​​each first opening region 12e is 0.086 mm 2As shown in FIG. 11C, in the second opening region 12f, the distance L46 between the vertices along one direction Y1 is set to 0.81 mm, the distance L47 between the vertices along the direction X1 perpendicular to the one direction is set to 0.1 mm, and the area of ​​each second opening region 12f is set to 0.022 mm 2 (square millimeters).

[0094] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the first opening region 12e and the second opening region 12f per unit area, is 97%.

[0095] 11(A), a virtual square region S with a side length of λ is set at an arbitrary position on the surface of the conductive layer 16 parallel to the XY plane. In this example, the minor axis direction of the elliptical first opening region 12e is aligned along the X direction, and the major axis direction is aligned along the Y direction.

[0096] Then, all the opening regions 12a that overlap even a part of the square region S in the XY plane are extracted. In this example, nine opening regions 12e are extracted as shown in Fig. 11(B). Furthermore, 20 opening regions 12f are extracted as shown in Fig. 11(C).

[0097] In each of the two types of first and second opening regions 12e and 12f having different areas, the maximum value of the distance between any two of the intersection points between the virtual line AX along the X direction and the periphery of each opening region 12e and 12f is set as the X-direction maximum value Lx. Also, the maximum value of the distance between any two of the intersection points between the virtual line AY along the Y direction and the periphery of each opening region 12a is set as the Y-direction maximum value Ly. In this example, in the elliptical first opening region 12e, the X-direction maximum value Lx coincides with the length L45 of the minor axis along the direction X1 of the elliptical shape, which is 0.11 mm. The Y-direction maximum value Ly coincides with the length L44 of the major axis along one direction Y1, which is 1.0 mm. In the second opening region 12f having an approximately rectangular shape, the maximum X-direction value Lx corresponds to the distance L47 between the vertices along the direction X1 perpendicular to the one direction, which is 0.1 mm, and the maximum Y-direction value Ly corresponds to the distance L46 between the vertices along the one direction Y1, which is 0.81 mm.

[0098] At this time, the maximum X-direction value Lx of all the extracted first opening regions 12e and all the extracted second opening regions 12f is equal to or less than λ / 4. The aspect ratio of each of the extracted first and second opening regions 12e and 12f is defined as Ly / Lx, and the average of the aspect ratios weighted according to the areas of the extracted first and second opening regions 12e and 12f is calculated using the above-mentioned formula 1.

[0099] In this case, there is at least one square region S in which the average aspect ratio is greater than 1. The conductive pattern is provided so that such a maximum X-direction value Lx and a square region S in which the average aspect ratio is achieved can be set.

[0100] In this example, since the extracted first and second opening regions 12e, 12f have different areas, the first and second opening regions 12e, 12f are weighted according to the area of ​​each opening region 12e, 12f as shown in Equation 1 to calculate the average aspect ratio, which is 8.7.

[0101] It is also preferable that the area ratio, which is the ratio of the total area of ​​the extracted first and second opening regions 12e, 12f having an aspect ratio greater than 1, is 10% or more. In Example 8, the aspect ratio of the first opening region 12e is 9.1 (rounded off to one decimal place) and the aspect ratio of the second opening region 12f is 8.1, both of which exceed 1, so the area ratio is 100%.

[0102] Example 9 In the following description of the ninth embodiment, only the points different from the eighth embodiment will be described, and the description of the same configurations and settings as those of the eighth embodiment will be omitted.

[0103] In Example 9, in the first opening region 12e, the length L44 of the major axis of the ellipse is set to 0.5 mm, the length L45 of the minor axis is set to 0.12 mm, and the area of ​​each first opening region 12e is 0.048 mm 2In the second opening region 12f, the distance L46 between the vertices along one direction is set to 0.41 mm, the distance L47 between the vertices along the direction perpendicular to the one direction is set to 0.11 mm, and the area of ​​each second opening region 12f is set to 0.013 mm 2 (square millimeters).

[0104] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the first opening region 12e and the second opening region 12f per unit area, is 97%.

[0105] 12(A), a virtual square region S with a side length of λ is set at an arbitrary position on the surface of the conductive layer 16 parallel to the XY plane. In this example, the minor axis direction of the elliptical first opening region 12e is aligned along the X direction, and the major axis direction is aligned along the Y direction.

[0106] Then, all the opening regions 12a that overlap even a part of the square region S in the XY plane are extracted. In this example, 16 opening regions 12e are extracted as shown in Fig. 12(B). Furthermore, 27 opening regions 12f are extracted as shown in Fig. 12(C).

[0107] In each of the two types of first and second opening regions 12e and 12f having different areas, the maximum value of the distance between any two of the intersection points between the virtual line AX along the X direction and the periphery of each opening region 12e and 12f is set as the X-direction maximum value Lx. Also, the maximum value of the distance between any two of the intersection points between the virtual line AY along the Y direction and the periphery of each opening region 12a is set as the Y-direction maximum value Ly. In this example, in the first opening region 12e having an elliptical shape, the X-direction maximum value Lx coincides with the length L45 of the short axis of the elliptical shape and is 0.12 mm. The Y-direction maximum value Ly coincides with the length L44 of the long axis and is 0.5 mm. In the second opening region 12f having an approximately rectangular shape, the X-direction maximum value Lx coincides with the distance L47 between the vertices along a direction perpendicular to one direction and is 0.11 mm, and the Y-direction maximum value Ly coincides with the distance L46 between the vertices along one direction and is 0.41 mm.

[0108] At this time, the maximum X-direction value Lx of all the extracted first opening regions 12e and all the extracted second opening regions 12f is equal to or less than λ / 4. The aspect ratio of each of the extracted first and second opening regions 12e and 12f is defined as Ly / Lx, and the average aspect ratio is calculated using the above-mentioned formula 1 by weighting according to the area of ​​each of the extracted first and second opening regions 12e and 12f.

[0109] In this case, there is at least one square region S in which the average aspect ratio is greater than 1. The conductive pattern is provided so that such a maximum X-direction value Lx and a square region S in which the average aspect ratio is achieved can be set.

[0110] In this example, since the extracted first and second opening regions 12e, 12f have different areas, the first and second opening regions 12e, 12f are weighted according to the area of ​​each opening region 12e, 12f as shown in Equation 1 to calculate the average aspect ratio, which is 4.0.

[0111] Furthermore, it is preferable that the area ratio, which is the ratio of the total area of ​​the extracted first and second opening regions 12e, 12f having an aspect ratio greater than 1, is 10% or more. In Example 9, the aspect ratio of the first opening region 12e is 4.2 (rounded off to one decimal place) and the aspect ratio of the second opening region 12f is 3.7, both of which exceed 1, so the area ratio is 100%.

[0112] Example 10 In the following description of the tenth embodiment, only the differences from the eighth embodiment will be described, and the description of the same configurations and settings as those of the eighth embodiment will be omitted.

[0113] In the tenth embodiment, in the first opening region 12e, the length L44 of the long axis of the ellipse is set to 0.25 mm, the length L45 of the short axis is set to 0.16 mm, and the area of ​​each first opening region 12e is 0.032 mm 2In the second opening region 12f, the distance L46 between the vertices along the direction Y1 is set to 0.21 mm, and the distance L47 between the vertices along the direction X1 perpendicular to the direction Y1 is set to 0.15 mm. The area of ​​each second opening region 12f is 0.0084 mm 2 (square millimeters).

[0114] In the plane of the conductive layer 16, the aperture ratio, which is the ratio of the total area of ​​the first opening region 12e and the second opening region 12f per unit area, is 97%.

[0115] 13(A), a virtual square region S with a side length of λ is set at an arbitrary position on the surface of the conductive layer 16 parallel to the XY plane. In this example, the minor axis direction of the elliptical first opening region 12e is aligned along the X direction, and the major axis direction is aligned along the Y direction.

[0116] Then, all the opening regions 12a that overlap even a part of the square region S in the XY plane are extracted. In this example, 24 opening regions 12e are extracted as shown in Fig. 13(B). Furthermore, 35 opening regions 12f are extracted as shown in Fig. 13(C).

[0117] In each of the two types of first and second opening regions 12e and 12f having different areas, the maximum value of the distance between any two of the intersection points between the virtual line AX along the X direction and the periphery of each opening region 12e and 12f is set as the X-direction maximum value Lx. Also, the maximum value of the distance between any two of the intersection points between the virtual line AY along the Y direction and the periphery of each opening region 12a is set as the Y-direction maximum value Ly. In this example, in the first opening region 12e having an elliptical shape, the X-direction maximum value Lx corresponds to the length L45 of the short axis of the elliptical shape, which is 0.16 mm. The Y-direction maximum value Ly corresponds to the length L44 of the long axis, which is 0.25 mm. In the second opening region 12f having an approximately rectangular shape, the X-direction maximum value Lx corresponds to the distance L47 between the vertices along a direction perpendicular to one direction, which is 0.15 mm, and the Y-direction maximum value Ly corresponds to the distance L46 between the vertices along one direction, which is 0.21 mm.

[0118] At this time, the maximum X-direction value Lx of all the extracted first opening regions 12e and all the extracted second opening regions 12f is equal to or less than λ / 4. The aspect ratio of each of the extracted first and second opening regions 12e and 12f is defined as Ly / Lx, and the average aspect ratio is calculated using the above-mentioned formula 1 by weighting according to the area of ​​each of the extracted first and second opening regions 12e and 12f.

[0119] In this case, there is at least one square region S in which the average aspect ratio is greater than 1. The conductive pattern is provided so that such a maximum X-direction value Lx and a square region S in which the average aspect ratio is achieved can be set.

[0120] In this example, since the extracted first and second opening regions 12e, 12f have different areas, the first and second opening regions 12e, 12f are weighted according to the area of ​​each opening region 12e, 12f as shown in Equation 1 to calculate the average aspect ratio, which is 1.5.

[0121] Furthermore, it is preferable that the area ratio, which is the ratio of the total area of ​​the extracted first and second opening regions 12e, 12f having an aspect ratio greater than 1, is 10% or more. In Example 10, the aspect ratio of the first opening region 12e is 1.6 (rounded off to one decimal place) and the aspect ratio of the second opening region 12f is 1.4, both of which exceed 1, so the area ratio is 100%.

[0122] (Other configurations of Examples 1 to 10) Other than the above-mentioned configuration, the first to tenth embodiments have the same configuration, which will be described below.

[0123] The radio wave reflector 11 has a square planar shape, and in Examples 1 to 7, the length L10 of one side of the radio wave reflector 11 was set to 32 mm, and in Examples 8 to 10, the length L10 of one side of the radio wave reflector 11 was set to 30 mm. The thickness L1 of the radio wave reflector 11 was set to 0.25 mm. The thickness L1 of the radio wave reflector 11 is the sum of the thickness L3 of the conductive layer 16, the thickness L2 of the base layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15. However, since the thickness L3 of the conductive layer 16 is much thinner than the respective thicknesses L2, L4, and L5 of the base layer 13, the adhesive layer 14, and the protective layer 15, the thickness L1 of the radio wave reflector 11 does not take into account the thickness L3 of the conductive layer 16. A synthetic resin material sheet made of PET (Lumirror 50T60, manufactured by Toray Industries, Inc.) was used as the base layer 13, and the thickness L2 of the base layer 13 was set to 50 μm. The conductor 12 of the conductive layer 16 is a linear metal thin film made of silver (Ag) and has a thickness (film thickness) L3 of 500 nm. The surface resistivity of the conductive layer 16 is 1.7 Ω / □. A rubber-based adhesive is used as the adhesive layer 14. In detail, the adhesive layer 14 is prepared by adding 100 parts by weight of a rubber-based polymer (a mixture of 50% by weight of a styrene-(ethylene-propylene)-styrene type block copolymer and 50% by weight of a styrene-(ethylene-propylene) type block copolymer, 15% styrene content, and 130,000 weight average molecular weight), 40 parts by weight of a synthetic resin (Mitsui Chemicals, Inc., FMR-0150), 20 parts by weight of a softener (JX Nippon Oil & Energy Corporation, LV-100), 0.5 parts by weight of an antioxidant (ADEKA Corporation, Adeka STAB AO-330), and 150 parts by weight of toluene to a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, a dropping funnel, and a stirring device, and stirring the mixture at 40° C. for 5 hours. The thickness L4 of the adhesive layer 14 was 150 μm. The induced dissipation factor of the adhesive layer 14 is 0.04. A synthetic resin sheet made of PET (Lumirror 50T60, manufactured by Toray Industries, Inc.) was used as the protective layer 15. The thickness L5 of the protective layer 15 was set to 50 μm. The thickness L1 of the radio wave reflector 11, the thickness L3 of the conductive layer 16, the thickness L2 of the base layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15 were determined by measuring any multiple locations and calculating the average value of the obtained measured values. For example, a reflectance spectroscopic film thickness measuring instrument (for example, F3-CS-NIR, manufactured by Filmetrics Inc.) was used as a measuring instrument to measure the thicknesses L1 to L5.

[0124] A method for manufacturing the radio wave reflector 11 will be described. First, the conductor 12 is formed on the base layer 13. A core layer of 0.01 to 3 μm is formed on one surface of a copper foil having a thickness of 5 to 200 μm, which has sufficient strength as a metal layer, by a method such as electrolytic or electroless plating. Then, a conductive layer 16 of a predetermined conductive pattern is formed on the surface of the core layer by a method such as electrolytic or electroless plating. Next, the entire conductive layer 16 is covered with the base layer 13. An adhesive is applied to the base layer 13 in advance. Then, the copper foil and the core layer are removed by etching. As a result, the conductor 12 is formed on the base layer 13.

[0125] Then, protective layer 15 is attached to the conductor 12 on the side opposite to base layer 13 with adhesive layer 14. Protective layer 15 is attached to conductor 12 on base layer 13 using adhesive layer 14 while taking care not to trap air bubbles. In this manner, radio wave reflector 11 is manufactured.

[0126] The conductive layer 16 can be manufactured by forming a conductive film, forming a pattern by etching, and extracting a conductive thin film having the pattern. Alternatively, a photosensitive resist is applied to a base film having a lift-off layer, forming a pattern by photolithography, filling the patterned portion with a conductor, and then extracting a conductive thin film having the pattern. The manufacturing method is not limited to the above, and examples of the conductive layer 16 include a method of adhering a metal thin film and a method of vapor-depositing a metal.

[0127] (evaluation) The aperture ratio, total light transmittance, and reflection loss were used to evaluate Examples 1 to 10. Tables 1 and 2 show the evaluation results. (Opening ratio) As described above, the aperture ratio is the ratio of the total area of ​​the open regions 12a per unit area on the plane of the conductive layer 16. The conductor 12 has low transparency, while the adhesive layer 14, the protective layer 15, and the base layer 13 have higher transparency than the conductor 12. Therefore, the higher the aperture ratio in the conductive layer 16, the higher the transparency. In Examples 1 to 10, the aperture ratio exceeds 90%, which contributes to the transparency of the radio wave reflector 11. (Total light transmittance) The total light transmittance was measured in accordance with the method defined in JISK 7375:2008 under the D65 standard light source (one of the standard light sources defined by the CIE (International Commission on Illumination)). Examples 1 to 10 were evaluated as having a total light transmittance of 85% or more, as "◎", as having a total light transmittance of more than 75% and less than 85%, as "◯", and as having a total light transmittance of less than 75%. All of Examples 1 to 10 had a total light transmittance of 75% or more, and can be said to be transparent enough not to obstruct the view.

[0128] It should be noted that Examples 1 to 10 were created to measure the aperture ratio and total light transmittance, and in order to actually reflect radio waves, it is preferable that the length L10 of one side is set to 15 cm or more and 400 cm or less.

[0129] (reflection loss) The reflection loss refers to the degree of loss in the amplitude ratio of the reflected wave to the incident wave relative to perfect reflection (amplitude ratio is 1). The reflection loss in Examples 1 to 10 was calculated by using the full-wave finite element simulation software ANSYS HFSS to define the radio wave reflector 11 corresponding to the above-mentioned Examples 1 to 10 and apply a periodic boundary condition to the periphery of Examples 1 to 10. The frequencies of the incident wave were set to 3 GHz, 20 GHz, 29 GHz, 60 GHz, 100 GHz, 200 GHz, and 300 GHz. In order to obtain the reflection loss using the above software, as described above, the length L10 of one side of the radio wave reflector 11 was set to 32 mm in Examples 1 to 7, and the length L10 of one side of the radio wave reflector 11 was set to 30 mm in Examples 8 to 10. However, the method of calculating the reflection loss is not limited to using the above software.

[0130] In Examples 1 to 10, the reflection loss of 1 dB or less was evaluated as "◎", the reflection loss of more than 1 dB and less than 2 dB was evaluated as "◯", and the reflection loss of 2 dB or more was evaluated as "X". In all of Examples 1 to 10, the reflection loss was less than 2 dB regardless of the frequency of the incident wave.

[0131] According to this embodiment, the conductive layer 16 of the radio wave reflector 11 has a high aperture ratio and is therefore highly transparent, and when the radio wave reflector 11 is used in a room, the view is not blocked, and the presence of the radio wave reflector 11 is not conspicuous, so that the atmosphere and scenery of the room are not hindered, and the scenery can be maintained in a good condition. In addition, in the radio wave reflector 11, when an incident wave with a frequency of 2 GHz or more and 300 GHz or less is regularly reflected, the strength of the reflected wave is sufficiently large compared to the incident wave, so that the radio wave can be reflected while maintaining a high reflection strength. Therefore, even if the radio wave has a short wavelength and is highly directional, it is possible to prevent blind spots from occurring as much as possible in the space inside the room, and it is not necessary to install a large number of radio wave reflectors in order to reduce blind spots.

[0132] [Table 1] [Table 2]

[0133] (Other embodiments) The conductive pattern of the conductor 12 may be any conductive pattern as long as the aperture ratio, which is the ratio of the area of ​​the open region 12a per unit area, is 85% or more on the plane of the conductive layer 16, and there is at least one square region S whose average aspect ratio, as described above, is greater than 1. Figures 14(A) to 14(D) show examples of other conductive patterns.

[0134] 14(A), a plurality of conductors 12A are arranged at predetermined intervals along the horizontal direction, and a plurality of conductors 12B extending in the vertical direction are arranged in a staggered pattern between the conductors 12A extending in the horizontal direction. The staggered pattern refers to a state in which a plurality of conductors 12B extending in the vertical direction are arranged at predetermined intervals in the horizontal direction, a plurality of conductors 12B forming one row are positioned between a plurality of conductors 12B forming an adjacent row in the vertical direction, and the conductors 12B in every other row are arranged in a straight line.

[0135] 14(B), the conductor 12A is disposed along the horizontal direction, while the conductors 12B and 12C extend along oblique directions inclined upward and downward with respect to the horizontal direction, and the conductors 12B and 12C intersect with each other on the conductor 12A, so that the shape of the opening region 12a is triangular.

[0136] In FIG. 14(C), hexagonal opening regions 12a formed by linear conductors 12 are periodically arranged, and in FIG. 14(D), pentagonal opening regions 12a formed by linear conductors 12 are periodically arranged.

[0137] Another embodiment of the present invention is shown in Fig. 15. In the radio wave reflector 11 shown in Fig. 15, conductive layers 16A and 16B are laminated in two layers in the up-down direction. The conductive layer 16A formed on the base layer 13A and the conductive layer 16B formed on the base layer 13B are aligned so that their conductive patterns overlap when viewed from above. The conductive patterns of the conductive layers 16A and 16B do not have to overlap when viewed from above, and the conductive layers 16A and 16B may be formed with different conductive patterns. The lower surface of the base layer 13B is attached onto the conductive layer 16A with an adhesive layer 14A, and the protective layer 15 is attached onto the conductive layer 16B with an adhesive layer 14B.

[0138] The radio wave incident on the radio wave reflector 11 is reflected by the first conductive layer 16B, but a part of the radio wave passes through the conductive layer 16B without being reflected by the conductive layer 16B. The radio wave that passes through the conductive layer 16B is reflected by the second conductive layer 16A. In this way, by stacking a plurality of conductive layers 16 including the conductors 12 in the vertical direction, the radio wave that passes through the upper conductive layer 16B can be reflected by the lower conductive layer 16A, and the reflection intensity of the radio wave reflector 11 can be kept higher than when there is only one conductor 12. The other configurations and functions are the same as those of the embodiment shown in Figs. 2 and 3, and corresponding configurations are denoted by the same reference numerals and detailed description thereof will be omitted.

[0139] 15, the conductive layer 16 formed on the base layer 13 is laminated in two layers, but it may be laminated in three or more layers. As the number of laminated conductive layers 16 increases, the reflection intensity increases, but the overall thickness of the radio wave reflector 11 increases, resulting in a decrease in total light transmittance and flexibility. For this reason, the number of laminated conductive layers 16 is appropriately set depending on the intended use, etc.

[0140] (Other embodiments) Fig. 16 shows another embodiment of the radio wave reflector 11. In the embodiment of Fig. 16, the radio wave reflector 11 includes a conductive layer 16 and a base layer 13, and does not include an adhesive layer 14 and a protective layer 15. Other configurations and functions are similar to those of the embodiments shown in Fig. 2 and Fig. 3, so that the same reference numerals are used to denote corresponding configurations and detailed descriptions thereof will be omitted.

[0141] (use) Any of the radio wave reflectors 11 described above may be used by being included in a building material 30. The building material 30 can be attached to a building as, for example, decorative material 30A such as wallpaper for walls, ceilings, and floors, wallpaper for partitions, and posters in a room or a corridor, and decorative material 30B such as transparent stickers for light covers, as shown in Fig. 17(A). By attaching decorative materials 30A and 30B including the radio wave reflector 11 to a wall surface 31 or a light cover 32, radio waves that enter the room from the outside through a window 33 or the like are reflected by the decorative materials 30A and 30B provided on the wall surface 31 or the light cover 32. This allows radio waves to reach a wider range in the indoor space S, improving the convenience of radio wave reception.

[0142] The radio wave reflector 11 may be formed as one held inside the building material 30. For example, the wall surface 31 itself or the light cover 32 itself, which is the building material 30, may be composed of the radio wave reflector 11. Furthermore, the building material 30 is not limited to the wall or light cover inside the room, but may be a partition, a pillar, a lintel, an exterior wall of a building, a window, or the like. For example, FIG. 17(B) is a plan view of the room, and the building material 30, which is the radio wave reflector 11, is formed as a corner pillar 30C having a curved surface at the corner of the room. Radio waves entering through the window 33 are reflected by the corner pillar 30C, and the radio waves reach a wider range of the indoor space S. Note that FIGS. 17(A) and 17(B) show application examples of the building material 30, and do not show the actual range of reflection of radio waves. The radio wave reflector 11 is not limited to the building material 30, and may be held inside a member made of a non-conductive material such as resin and used in any location.

[0143] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. The dimensions, materials, shapes, and relative arrangements of the components described as embodiments or shown in the drawings are merely illustrative examples, and are not intended to limit the scope of the present invention. For example, expressions expressing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only strictly express such arrangements, but also express a state in which they are relatively displaced with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions expressing that things are in an equal state, such as "same," "equal," and "homogeneous," not only strictly express a state in which they are equal, but also express a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions expressing shapes such as a square shape or a cylindrical shape not only express shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also express shapes including uneven parts and chamfered parts to the extent that the same effect is obtained. The terms "comprises," "includes," "has," "includes," "contains," or "has" of a component are not exclusive terms that exclude the presence of other components. In addition, the drawings are not drawn to scale. [Explanation of symbols]

[0144] 11 Radio wave reflector 12 Conductors 12a (12c~12f) Opening area (first opening area, second opening area) 13 Base material layer 13a Edge of base layer 14 Adhesive layer 15 Protective layer 16 Conductive layer L6 Conductor line width L10 Length of one side of the radio wave reflector Lx Maximum value in X direction Ly Y-direction maximum value S square area X: A direction perpendicular to the direction of vibration of the electric field of the radio wave Y: Along the direction of the electric field vibration of the radio wave AX An imaginary line along the X direction AY An imaginary line along the Y direction

Claims

1. A radio wave reflector for reflecting radio waves, a conductive layer having a conductive pattern formed by linear conductors and an open area surrounded by the conductors and free of the conductors; an aperture ratio, which is a ratio of an area of ​​the opening region per unit area in a plane of the conductive layer, is 85% or more; An X direction and a Y direction perpendicular to each other are arbitrarily set on the plane of the conductive layer; Assume that an incident wave of radio waves is such that the direction of a vector obtained by orthogonally projecting a vector in the vibration direction Y' of the electric field onto the conductive layer is the Y direction, and the direction of a vector obtained by orthogonally projecting a vector in the direction X' perpendicular to the vibration direction Y' of the electric field onto the conductive layer is the X direction, and the wavelength of the radio waves of the highest frequency in a predetermined frequency band of radio waves reflected by the radio wave reflector is λ, A virtual square region having a side length of λ is set at an arbitrary position on the plane of the conductive layer, All of the opening regions overlapping with the square region in the XY plane are extracted, and in each of the extracted opening regions, the maximum value of the distance between any two of the intersection points between a virtual line along the X direction and a periphery of each of the opening regions is defined as Lx, and the maximum value of the distance between any two of the intersection points between a virtual line along the Y direction and a periphery of each of the opening regions is defined as Ly, Lx of all the extracted aperture regions is λ / 4 or less, A radio wave reflector in which, when the aspect ratio of each of the extracted opening regions is Ly / Lx, there is at least one square region such that the average aspect ratio calculated by weighting the respective extracted opening regions according to their areas is greater than 1.

2. The radio wave reflector according to claim 1 , wherein the conductive layer has two or more opening regions with different areas.

3. 2. The radio wave reflector according to claim 1, wherein a ratio of a total area of ​​the opening regions having an aspect ratio greater than 1 to a total area of ​​all the extracted opening regions is 10% or more.

4. The conductive material is provided on a surface of a substrate layer. The conductive layer is composed of the conductors parallel to the Y direction, The radio wave reflector according to claim 1 , wherein the open area is an area surrounded by the conductor and an edge of the base material layer.

5. 2. The radio wave reflector according to claim 1, wherein the predetermined frequency band of radio waves reflected by said radio wave reflector is 2 GHz or more and 300 GHz or less.

6. 2. The radio wave reflector according to claim 1, which has a total light transmittance of 75% or more under a D65 standard light source.

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