TW202416588A - Radio wave reflecting body, manufacturing method for radio wave reflecting body, construction method for radio wave reflecting body - Google Patents

Abstract

The present invention makes it possible to protect a conductor without damaging radio wave reflection properties. A radio wave reflecting body 11 comprises: a conductor layer 16 that includes a conductor 12 which reflects radio waves; and a protective layer 15 that protects the conductor layer 16. If a pencil hardness test is performed on the radio wave reflecting body 11, the pencil hardness, with a surface load of 500g on the protective layer 15, is at least F.

Description

Radio wave reflector, method for manufacturing radio wave reflector, and method for constructing radio wave reflector

The present invention relates to a radio wave reflector.

In mobile phones and wireless communications, radio waves in the frequency band of about 3 GHz to 300 GHz, called centimeter waves or millimeter waves, are used. Since these short-wavelength radio waves have strong straightness, they are not easy to bend even if there are obstacles. Therefore, in order to make the radio waves reach a wider range, reflectors are installed on the walls, floors, ceilings, columns and other surfaces of buildings (hereinafter referred to as "walls, etc.").

For example, Patent Document 1 describes a communication system that places a monopole antenna and a metal reflector for reflecting radio waves in the space under the floor of a room. The metal reflector diffuses the radio waves output from the monopole antenna to the space under the floor, and prevents the radio waves from leaking from the space under the floor to the outside of the living room (building) or being absorbed by the floor of the building. [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2010-258514

[The problem that the invention wants to solve]

However, conventional metal reflectors are simply reflectors made of metal. In order to reflect radio waves more efficiently, the inventors of the present invention considered laminating a conductive layer having a conductor and a protective layer for protecting the conductive layer.

However, if the surface hardness of the protective layer is weak, it may not be able to fully protect the conductor and may impair the radio wave reflectivity.

The purpose of the present invention is to provide a radio wave reflector that can protect the conductor without damaging the radio wave reflectivity. [Technical means to solve the problem]

In order to achieve the above-mentioned object, the present invention includes the subject matter described in the following items.

Item 1. A radio wave reflector, comprising: a conductive layer comprising a conductor for reflecting radio waves; and a protective layer for protecting the conductive layer; and when a pencil hardness test is performed on the radio wave reflector, the pencil hardness of the protective layer when a surface load of 500 g is applied is above F.

Item 2. The radio wave reflector of Item 1, wherein the thickness of the protective layer is greater than 38 μm.

Item 3. The radio wave reflector of Item 1 or Item 2, wherein, when the protective layer is subjected to a pencil hardness test, the pencil hardness of the protective layer when a surface load of 500 g is applied is F or higher.

Item 4. The radio wave reflector according to any one of Items 1 to 3 further comprises a bonding layer, wherein the bonding layer is disposed between the conductive layer and the protective layer and bonds the conductive layer to the protective layer, and the hydroxyl value of the bonding layer is 5 mgKOH/g or more.

Item 5. The radio wave reflector according to Items 1 to 4 further comprises a bonding layer, wherein the bonding layer is disposed between the conductive layer and the protective layer and bonds the conductive layer to the protective layer, and the acid value of the bonding layer is 50 mgKOH/g or less.

Item 6. The radio wave reflector according to any one of Items 1 to 5, wherein the moisture permeability of the protective layer at 40°C and 90% rh is not more than 20 g/m ² · 24 h.

Item 7. The radio wave reflector as described in any one of Items 1 to 6, wherein the decrease rate of the adhesion of the protective layer to the adhered layer after a heat and moisture resistance test is 50% or less.

Item 8. The radio wave reflector according to any one of Items 1 to 7, wherein the total light transmittance of the radio wave reflector is 70% or more.

Item 9. The radio wave reflector according to any one of Items 1 to 8, further comprising a bonding layer, wherein the bonding layer is disposed between the conductive layer and the protective layer and bonds the conductive layer to the protective layer, and the bonding layer does not contain an ultraviolet radiation inhibitor.

Item 10. A radio wave reflector as described in any one of items 1 to 9, wherein the conductive layer has a region without the conductive body and the conductive body formed in a manner surrounding the region, the region includes a plurality of regions of the same shape, and the plurality of regions of the same shape are arranged at certain intervals.

Item 11. The radio wave reflector according to any one of Items 1 to 10, wherein the surface resistivity of the radio wave reflector after heat and moisture resistance tests is 100 Ω/□ or less.

Item 12. The radio wave reflector according to any one of Items 1 to 11, wherein the protective layer contains an ultraviolet radiation inhibitor or has its surface subjected to an ultraviolet radiation blocking treatment.

Item 13. The radio wave reflector according to any one of Items 1 to 12, wherein the haze of the radio wave reflector is 30% or less.

Item 14. The radio wave reflector according to any one of Items 1 to 13, wherein the total light transmittance of the radio wave reflector after a light resistance test is 70% or more.

Item 15. The radio wave reflector according to any one of Items 1 to 14, wherein the yellowing degree Δb* of the radio wave reflector before and after the light resistance test is 15 or less.

Item 16. The radio wave reflector as described in any one of items 1 to 15 comprises a laminated body having the above-mentioned protective layer and the above-mentioned conductive layer, and when viewed from above, all the above-mentioned conductive bodies are covered by the above-mentioned protective layer.

Item 17. A radio wave reflector as in Item 16, wherein the laminate further comprises a bonding layer for bonding the protective layer to the conductive layer, the conductive body being arranged on the inner side of the end edge of the protective layer when viewed from above, and the conductive body being covered by the bonding layer when viewed from the side.

Item 18. A radio wave reflector as described in Item 17, wherein the conductive layer further includes a substrate supporting the conductive body, the conductive body is located between the substrate and the protective layer, and is arranged on the inner side of the edge of the substrate when viewed from above.

Item 19. The radio wave reflector of any one of Items 16 to 18, wherein the conductor is arranged at an inner side at least 5 mm away from an edge of the protective layer when viewed from above.

Item 20. The radio wave reflector as described in any one of Items 16 to 19, wherein a sealing material for preventing the above-mentioned conductor from being exposed is provided at least at a position corresponding to the above-mentioned conductive layer around the above-mentioned laminate.

Item 21. A radio wave reflector as described in any one of Items 16 to 20, wherein the difference between the yellowness index after the heat and humidity resistance test and the yellowness index before the heat and humidity resistance test is 3 or less, and the heat and humidity resistance test is the following test: after placing the radio wave reflector in a constant temperature and humidity tank adjusted to a temperature of 60°C and a humidity of 95%RH for 500 hours, the radio wave reflector is taken out of the tank and left to stand at room temperature for 4 hours.

Item 22. A radio wave reflector as described in any one of Items 1 to 21, wherein, when an incident wave with a frequency of 3 GHz to 300 GHz is normally reflected by the radio wave reflector after the heat and humidity resistance test and the radio wave reflector before the heat and humidity resistance test, there is at least one frequency of the incident wave for which the difference between the intensity of the reflected wave of the radio wave reflector after the heat and humidity resistance test and the intensity of the reflected wave of the radio wave reflector before the heat and humidity resistance test is within 3 dB, and the heat and humidity resistance test is the following test: after placing the radio wave reflector in a constant temperature and humidity tank adjusted to a temperature of 60°C and a humidity of 95%RH for 500 hours, the radio wave reflector is taken out from the tank and left to stand at room temperature for 4 hours.

Item 23. A method for manufacturing a radio wave reflector of Item 20, comprising: a step of forming the above-mentioned laminated body; and a step of providing a sealing material for preventing the above-mentioned conductor from being exposed; and in the above-mentioned radio wave reflector, the above-mentioned sealing material is located at a position around the above-mentioned laminated body at least corresponding to the above-mentioned conductive layer.

Item 24. A method for constructing a radio wave reflector according to Item 20, comprising: a step of installing the above-mentioned laminate at a setting position; and a step of installing a sealing material for preventing the above-mentioned conductor from being exposed; and in the above-mentioned radio wave reflector, the above-mentioned sealing material is located at a position around the above-mentioned laminate at least corresponding to the above-mentioned conductive layer.

Item 25. A method for constructing a radio wave reflector as in Item 24, wherein, in the above-mentioned installation step, a plurality of the above-mentioned laminated bodies are installed at intervals at the installation location, and in the above-mentioned step of installing the sealing material, the above-mentioned sealing material is installed in the space between the adjacent above-mentioned laminated bodies when the plurality of the above-mentioned laminated bodies are installed at intervals at the installation location. [Effect of the Invention]

The radio wave reflector of the present invention has the advantages of being able to protect the conductor without damaging the radio wave reflectivity.

<Implementation>  (Overall structure of the radio wave reflector 11)  The implementation of the present invention is described below with reference to the drawings. As shown in FIG1 , the radio wave reflector 11 of the present implementation is a sheet-like component capable of reflecting radio waves. The radio wave reflector 11 is configured, for example, to reflect radio waves output from a radio wave generating unit 20. The radio waves reflected by the radio wave reflector 11 are received by a receiving unit 21. As shown in FIG2 , the radio wave reflector 11 is sequentially layered with a conductive layer 16 including a conductor 12, a bonding layer 14, and a protective layer 15.

The "sheet" mentioned in this specification refers to a shape in which the thickness of the object is less than 10% of the maximum length between the outer edges when viewed from above. When the shape when viewed from above is a rectangle, the "maximum length between the outer edges when viewed from above" means the length of the diagonal. When the shape when viewed from above is a circle, the "maximum length between the outer edges when viewed from above" means the length of the diameter. In this specification, films, foils, thin films, etc. are also included in the "sheet".

The radio wave generator 20 is a device that outputs radio waves. The radio wave generator 20 of this embodiment is a communication device having a transmission antenna, and the transmission antenna can output a wireless signal using radio waves as a medium. Examples of the radio wave generator 20 include: a fixed base station, a mobile phone base station, a radio wave transmitter, a wireless terminal, etc.

The receiving unit 21 is a device capable of receiving radio waves. The receiving unit 21 of this embodiment is a communication device having a receiving antenna. Examples of the receiving unit 21 include: a smart phone, a mobile phone, a tablet terminal, a notebook PC, a portable game console, a repeater, a radio, a television, and the like.

The radio wave reflector 11 of the present embodiment can reflect radio waves, for example, the frequency of the incident wave is in any range of 3 GHz to 5 GHz, 25 GHz to 30 GHz, and 100 GHz to 300 GHz. The "radio wave that can be reflected" mentioned here means having at least one of the following radio waves, the intensity of the outgoing wave of regular reflection (sometimes referred to as "regular reflection intensity") is -30 dB to 0 dB relative to the intensity of any incident wave with an incident angle of 15 degrees to 75 degrees. It is preferred that the regular reflection intensity is -30 dB to 0 dB regardless of which incident wave with an incident angle of 15 degrees to 75 degrees.

More specifically, it is preferred that the regular reflection intensity be -30 dB or more and 0 dB or less with respect to the incident wave at a frequency of 28.5 GHz, and it is more preferred that the regular reflection intensity be -30 dB or more and 0 dB or less with respect to the incident wave in the entire frequency band from 20 GHz to 60 GHz, and it is further preferred that the regular reflection intensity be -30 dB or more and 0 dB or less with respect to the incident wave in the entire frequency band from 3 GHz to 300 GHz.

The regular reflection intensity is preferably smaller than the attenuation of the incident wave. The regular reflection intensity relative to the incident wave is preferably greater than -25 dB and less than 0 dB, more preferably greater than -22 dB and less than 0 dB, further preferably greater than -20 dB and less than 0 dB, and further preferably greater than -15 dB and less than 0 dB.

By making the regular reflection intensity relative to the incident wave greater than -30 dB, the radio wave reflector 11 can reflect radio waves while maintaining the reflection intensity. As a result, the receiving unit 21 can receive radio waves with a practical intensity. The "reflection intensity" and "regular reflection intensity" in this specification refer to the intensity when the distance between the reflection point 11a and the measurement point is 1 m. In addition, the regular reflection intensity is measured in a flat state without bending or folding the radio wave reflector 11.

As shown in FIG3 , the radio wave reflector 11 of this embodiment is a quadrilateral (including a square and a rectangle) when viewed from above. The length L10 of one side of the radio wave reflector 11 is preferably 20 cm or more, more preferably 100 cm or more, and further preferably 200 cm or more. On the other hand, the upper limit of the length L10 of one side of the radio wave reflector 11 is not particularly limited, and is, for example, 400 cm or less. If the length L10 of one side is 20 cm or more, it is easy to reflect radio waves with sufficient intensity.

The shape of the radio wave reflector 11 is not limited to a quadrilateral, and may be a geometric shape such as a triangle, a pentagon, a hexagon, a circle, an ellipse, or a non-geometric shape. In the radio wave reflector 11, the maximum value of the distance between the ends is preferably 20 cm to 400 cm. The "maximum value of the distance between the ends" refers to the size of the diagonal when the radio wave reflector 11 is a rectangle, the size of the diameter when the radio wave reflector 11 is a circle, and the length of the major axis when the radio wave reflector 11 is an ellipse.

The thickness L1 of the radio wave reflector 11 is preferably 0.01 mm or more, more preferably 0.05 mm or more, and further preferably 0.2 mm or more. On the other hand, the upper limit of the thickness L1 of the radio wave reflector 11 is preferably 0.5 mm or less, and more preferably 0.4 mm or less. By making the thickness L1 of the radio wave reflector 11 0.01 mm or more, it is possible to maintain strength while having flexibility. By making the thickness L1 of the radio wave reflector 11 0.5 mm or less, when the radio wave reflector 11 is bent, it is not easy to bend, and as a result, stress concentration is not easy to occur in the conductor 12. The "bending" mentioned here means bending accompanied by plastic deformation in any layer of the radio wave reflector 11.

When the radio wave reflector 11 is subjected to a pencil hardness test, the pencil hardness of the protective layer 15 when the surface load is 500 g is preferably "F" or higher, more preferably "H" or higher, and further preferably "4H" or higher. The "pencil hardness test" described in this specification is based on the test of JIS K 5600-5-4 (1999). In addition, "surface load 500 g" means that if the load applied to the surface during the pencil hardness test is 500 g ± 10 g, it is included therein.

In addition, the radio wave reflector 11 preferably has a decrease rate of adhesion of the protective layer 15 to the adhered layer after the heat and moisture resistance test of 50% or less, more preferably 45% or less, and further preferably 40% or less. The "adhered layer" described in this specification means a layer that directly contacts the target layer. In this embodiment, the adhered layer of the protective layer 15 is the adhesive layer 14. The adhesion is measured by the tensile adhesion strength test according to JIS K 6849 (1994).

The heat and humidity resistance test is a test as follows: the radio wave reflector 11 is placed in a constant temperature and humidity tank adjusted to a temperature of 60°C and a humidity of 95% rh (relative humidity) and left there for 500 hours. The radio wave reflector 11 is then taken out of the constant temperature and humidity tank and left there at room temperature for 4 hours to check changes in properties.

The difference between the intensity of the reflected wave of the radio wave reflector 11 after the heat and humidity test and the intensity of the reflected wave of the radio wave reflector 11 before the heat and humidity test is preferably within 3 dB. The incident angle of the incident wave for which the difference in the intensity of the reflected wave before and after the heat and humidity test is within 3 dB is preferably at least one angle between 15 degrees and 75 degrees, more preferably 45 degrees, and more preferably all angles within the angle range of 15 degrees and 75 degrees. The frequency of the incident wave for which the difference in the intensity of the reflected wave before and after the heat and humidity test is within 3 dB is preferably at least one between 3 GHz and 300 GHz, and more preferably, all frequencies in the frequency band between 3 GHz and 300 GHz.

In addition, the surface resistivity of the radio wave reflector 11 after the heat and humidity resistance test is preferably 100 Ω/□ or less, more preferably 50 Ω/□ or less, and further preferably 20 Ω/□ or less. By making the surface resistivity after the heat and humidity resistance test 20 Ω/□ or less, the radio wave reflector 11 can be placed in a high temperature and high humidity environment for a long time without damaging the reflection strength, and can maintain the radio wave reflector 11 with practicality.

The surface resistivity of the radio wave reflector 11 before the heat and moisture resistance test is preferably 0.003 Ω/□ to 10 Ω/□, more preferably 0.01 Ω/□ to 9 Ω/□, and further preferably 0.02 Ω/□ to 8 Ω/□. The surface resistivity is a value measured when the radio wave reflector 11 is placed on a placement surface formed by a plane.

The change rate of the surface resistivity of the radio wave reflector 11 after the heat and humidity test relative to that before the heat and humidity test is preferably 20% or less, more preferably 17% or less, and further preferably 15% or less. When the surface resistivity before the heat and humidity test is set as _r1 and the surface resistivity after the heat and humidity test is set as _r2 , the change rate r can be obtained by r = ( _r1 - _r2 ) / _r1 × 100

The reflection intensity of radio waves varies according to the surface resistivity. If the change rate r of the surface resistivity of the radio wave reflector 11 is small, the reflection intensity is not easy to decrease. Since the change rate r of the surface resistivity of the radio wave reflector 11 during the heat and humidity resistance test is less than 20%, the reflection intensity of the radio wave reflector 11 will not be greatly reduced even after the heat and humidity resistance test, and sufficient radio wave reflection intensity can be achieved.

In addition, regarding the radio wave reflector 11, the change rate of the surface resistivity before and after the radio wave reflector 11 is bent along the surface of the member having a curvature radius of 200 mm (also referred to as "the change rate of the surface resistivity when bent") R can be not less than -10% and not more than 10%. The change rate of the surface resistivity when bent R means the ratio of the change in the surface resistivity R2 when the radio wave reflector 11 is bent along the surface of the member having a curvature radius of 200 mm relative to the surface resistivity _R1 of the radio wave reflector 11 when the radio wave reflector ₁₁ is flat. The change rate of the surface resistivity R can be obtained by R = ( _R2 - _R1 ) / _R1 × 100.

The reflection intensity of radio waves varies according to the surface resistivity. However, since the change rate R of the surface resistivity when the radio wave reflector 11 is bent is between -10% and 10%, even when the radio wave reflector 11 is bent, sufficient reflection intensity of radio waves can be achieved as in the flat state.

In this specification, surface resistivity means the surface resistance per 1 ^cm2 . The surface resistivity can be measured by the four-terminal method in accordance with JIS K 6911 by bringing the measuring terminal into contact with the surface of the conductive layer. In addition, the surface resistivity is measured as the surface resistivity of the conductive body 12 of the conductive layer 16. In the case where the conductive body 12 of the conductive layer 16 is not exposed due to protection by a resin sheet or the like, it can be measured by the eddy current method using a non-contact resistance meter (manufactured by Napson Co., Ltd., trade name: EC-80P or its equivalent).

The radio wave reflector 11 is preferably transparent as a whole. That is, the radio wave reflector 11 is preferably transparent. The conductive layer 16, the bonding layer 14 and the protective layer 15 can be formed of a material having visible light transparency and/or a thickness having visible light transparency. "Transparent" here means that an object located on one side of the radio wave reflector 11 can be seen from the other side, and the total light transmittance may not be 100%. "Transparent" includes semi-transparency. In addition, the radio wave reflector 11 can be colored.

The radio wave reflector 11 preferably has a total light transmittance of 70% or more, more preferably 75% or more, and further preferably 80% or more. In this specification, "total light transmittance" means the transmittance of light from a D65 standard light source. The total light transmittance is measured in accordance with JIS K 7375 (2008). The radio wave reflector 11 preferably has a total light transmittance of 70% or more, more preferably 75% or more, and further preferably 80% or more after the following light resistance test.

The radio wave reflector 11 preferably has a haze of 30% or less. Haze refers to the turbidity of the radio wave reflector 11 and is defined in JIS-K7136:2000. In particular, after a light resistance test, the haze is preferably 30% or less.

The light resistance test is a test as described below. The radio wave reflector 11 is placed in a tank of a measuring device (e.g., Xenon Sunshine Weather Ometer Ci4000 manufactured by ATLAS). The tank is set to an irradiance of 60 W/m ² (300-400 nm), a black standard temperature (BST) of 65±3°C, a humidity of 50±5%RH, and a tank temperature of 38°C. The light is irradiated for 1300 hours (one year's worth of direct sunlight), and changes in the properties of the radio wave reflector 11 are confirmed.

The yellowing degree Δb* of the radio wave reflector 11 before and after the light fastness test is preferably 15 or less. The yellowing degree Δb* refers to the difference (b*2-b*1) between the intensity b*1 of the color (yellow) of +b* before the light fastness test and the intensity b*2 of the color (yellow) of +b* after the light fastness test in the L*a*b* color system defined by CIE (International Commission on Illumination). The larger the value, the stronger the color change to yellow. If the yellowing degree Δb* is 15 or less, the change of the radio wave reflector 11 to yellow is not easily visible, and the influence of color change or deterioration is small. The yellowing degree Δb* is measured in accordance with JIS Z 8781-4.

The difference between the yellowness index of the radio wave reflector 11 after the heat and moisture resistance test and the yellowness index before the heat and moisture resistance test is 3 or less. The yellowness index is also called yellowness, which means the degree of hue from colorless or white to yellow. The yellowness index can be obtained by the method in accordance with JISK7373:2006. The difference in yellowness index is an indicator for evaluating yellowing, which is a deterioration phenomenon of the radio wave reflector 11. The smaller the difference in yellowness index, the smaller the deterioration. The yellowness index is different from the yellowness degree Δb* mentioned above. The yellowness index can be obtained using the XYZ color system defined by CIE (International Commission on Illumination).

The bending modulus of the radio wave reflector 11 is preferably 0.05 GPa or more and 4 GPa or less. By making the bending modulus within the above range, the radio wave reflector 11 has flexibility, and the radio wave reflector 11 can be bent and attached to a curved surface or a spherical surface without bending or breaking the radio wave reflector 11. The bending modulus is measured in accordance with JIS K7171. In this specification, "flexibility" means the property of bending without breaking or plastic deformation even when a bending force is applied at normal temperature and pressure.

The radio wave reflector 11 preferably has a longitudinal elastic modulus of 0.01 GPa or more and 80 GPa or less. By making the longitudinal elastic modulus within the above range, the radio wave reflector 11 can be easily deformed, and the radio wave reflector 11 can be bent without breaking the radio wave reflector 11, so that it can be attached to a curved surface with a curvature radius of 200 mm or more. The longitudinal elastic modulus is also called Young's modulus or tensile elastic modulus, which is defined by JIS K7161-2014 and is measured according to JIS K 7127 (1999).

The radio wave reflector 11 of this embodiment has at least the flexibility to be attached to a curved surface with a curvature radius of 200 mm or more, and preferably has the flexibility to be attached to a curved surface with a curvature radius of 100 mm or more.

The radio wave reflector 11 may have plasticity. Plasticity means the property that it can be deformed by applying external pressure, and when the deformation exceeds the elastic limit by applying pressure, the deformed shape is maintained even if the force is removed. That is, the conductive layer 16, the bonding layer 14 and the protective layer 15 may all have plasticity, or at least one of the conductive layer 16, the bonding layer 14 and the protective layer 15 may have plasticity.

The surface roughness Sa of the conductor 12 is not particularly limited, but is preferably 1 μm to 7 μm, and more preferably 1.03 μm to 6.72 μm. When the surface roughness Sa is within this range, radio waves can be easily diffusely reflected.

The surface roughness Sa is obtained by using the arithmetic mean height of ISO 25178 and is measured in accordance with ISO 25178. The surface roughness Sa of the conductor 12 can be obtained by measuring the surface roughness at a plurality of locations on the surface of the conductor 12 using a laser microscope (product name VK-X1000/1050, manufactured by KEYENCE, or its equivalent) and calculating the average value of the obtained measured values.

As shown in FIG1 , the radio wave reflector 11 is preferably such that when the receiving angle position of the reflected wave changes within the angle range α of more than -15 degrees and less than +15 degrees relative to the reflected wave A2 of the regular reflection in the virtual plane including the incident wave A1 and the reflected wave, the kurtosis of the distribution of the intensity of the reflected wave at each receiving angle position becomes less than -0.4. The kurtosis is more preferably less than -1.0, further preferably less than -1.1, and further preferably less than -1.2. The lower limit of the kurtosis is not particularly limited, for example, it is greater than -0.5. On the virtual plane, there are the reflection point 11a on the reflection surface of the radio wave reflector 11, the radio wave generation source 20, and the receiving part 21 of the reflected wave. The kurtosis is measured in a state where the radio wave reflector 11 is made into a planar state.

Kurtosis is a statistic that indicates the degree to which a distribution deviates from a normal distribution. It indicates the sharpness of the peak and the spread of the tail. As shown in FIG1 , the radio wave output from the radio wave generating source 20 is incident on the radio wave reflector 11 at an incident angle θ1 and is regularly reflected at an output angle θ2. The receiving angle position i of the receiving unit 21 is moved within an angle range α of -15 degrees to +15 degrees at specific angles (for example, every 5 degrees) with respect to the reflected wave A2 of the regular reflection of the radio wave, with the reflection point 11a as the center, and the reflection intensity x is measured. The receiving angle position i of the receiving unit 21 is located on an arc centered on the reflection point 11a. The average value of the reflection intensity x _i (i: 1, 2, ..., n) at each receiving angle position i is set to , when the standard deviation is set to s, the kurtosis can be calculated according to the following formula.

When the kurtosis is a negative value, it means that the intensity data at each angle position is flatter than the normal distribution, that is, the data is dispersed from the average value and the tail of the distribution is expanded. The smaller the kurtosis value, the flatter the distribution. In this embodiment, by setting the kurtosis to less than -0.4, the difference in reflection intensity caused by the receiving angle position becomes smaller within the angle range α of ±15 degrees relative to the reflected wave of the regular reflection.

(Structure of each layer of the radio wave reflector 11) Below, each layer of the radio wave reflector 11 is described in more detail. In the following description, the direction in which multiple layers are stacked is defined as the "up and down direction". In addition, when observing the radio wave reflector 11 along the up and down direction, "longitudinal" and "lateral" are defined. However, the definition of these directions is only for explanation and is not for specific use. In addition, each figure is only a schematic diagram and does not represent a strict reduction scale.

As shown in FIG2 , the radio wave reflector 11 has a laminate 18 having a plurality of layers. The laminate 18 has: a conductive layer 16 including a conductive body 12 for reflecting radio waves; and a protective layer 15 for protecting the conductive layer 16. The laminate 18 may further include a bonding layer 14 including a bonding agent for bonding the conductive layer 16 to the protective layer 15. In this embodiment, the radio wave reflector 11 has the bonding layer 14 and the protective layer 15 sequentially laminated on the conductive body 12 of the conductive layer 16.

(Conductive layer 16) The conductive layer 16 is a layer having a conductor 12. The conductive layer 16 includes a substrate 13 and a conductor 12 for reflecting radio waves. The conductor 12 is located between the substrate 13, the bonding layer 14, and the protective layer 15. Furthermore, the conductive layer 16 may not include the substrate 13 but may be composed of the conductor 12. In this case, the protective layer 15 supports the conductor 12 as the substrate 13.

(Substrate 13) The substrate 13 supports the conductor 12. In the present embodiment, the substrate 13 is formed to have a rectangular shape (more specifically, a square shape) when viewed from above. The substrate 13 is formed to have a uniform thickness over the entire surface. However, the thickness of the substrate 13 may be uneven, for example, it may be formed in a wedge shape, it may partially have a spherical surface, or it may be formed in a three-dimensional shape with concave and convex shapes.

As the substrate 13, for example, synthetic resin, FRP (Fiber Reinforced Plastics), carbon, glass, etc. can be listed. As the synthetic resin, for example, one or more of the group consisting of PET (polyethylene terephthalate), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyoxymethylene, 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 can be listed. As the substrate, it can also be a composite material of these synthetic resins. The substrate 13 of the present embodiment is composed of a PET sheet.

The thickness L2 of the substrate 13 is preferably 15 μm or more, more preferably 20 μm or more, and further preferably 25 μm or more. On the other hand, the upper limit of the thickness L2 of the substrate 13 is preferably 200 μm or less, more preferably 150 μm or less, and further preferably 125 μm or less.

The substrate 13 is preferably flexible. The substrate 13 preferably has a higher longitudinal elastic modulus than the protective layer 15. The longitudinal elastic modulus of the substrate 13 is, for example, preferably 1 GPa or more, more preferably 1.2 GPa or more, and further preferably 1.5 GPa or more. On the other hand, the upper limit of the longitudinal elastic modulus of the substrate 13 is, for example, preferably 4 GPa or less, more preferably 3.8 GPa or less, and further preferably 3.5 GPa or less. (Conductor 12)

The conductor 12 is a conductor that reflects radio waves. The conductor 12 is formed on the upper surface of the substrate 13. The conductor 12 is formed, for example, by wet etching or dry etching. Examples of wet etching include screen printing, photolithography, offset printing, etc. Examples of dry etching include reactive gas etching, reactive ion etching, reactive ion beam etching, ion beam etching, reactive laser beam etching, etc.

Furthermore, the conductor 12 may be embedded in a resin to form a thin film. For example, after the conductor film is formed, a pattern may be formed by etching, and the conductive thin film having the pattern may be taken out. Alternatively, a photosensitive anti-etching agent may be applied on a base film provided with a peeling layer, and a pattern may be formed by photolithography. After the conductor is filled in the patterned part, the conductive thin film having the pattern may be taken out. Furthermore, the conductor 12 may be connected to a metal thin film, or may be evaporated metal.

When a thin film conductor 12 is used, a thin film (conductive film layer) having the conductor 12 is laminated on the substrate 13 to form the conductive layer 16 .

As the conductor 12, for example, at least one of silver, gold, copper, platinum, aluminum, titanium, polysilicon, indium tin oxide, and alloys (for example, alloys containing nickel, chromium, and molybdenum) can be cited. As alloys containing nickel, chromium, and molybdenum, for example, various grades of Herschel alloys such as B-2, B-3, C-4, C-2000, C-22, C-276, G-30, N, W, and X can be cited.

The thickness L3 of the conductor 12 is preferably 5 nm or more, more preferably 0.05 μm or more. On the other hand, the upper limit of the thickness L3 of the conductor 12 is preferably 10 μm or less. If the thickness L3 of the conductor 12 is 5 nm or more, appropriate radio wave intensity can be ensured.

The conductive layer 16 preferably has a coverage of 1% to 50%, more preferably 1% to 10%. The coverage refers to the ratio of the area occupied by the conductor 12 per unit area in the area where the conductor 12 is provided on the upper surface of the substrate 13 when viewed from above. The area where the conductor 12 is provided refers to the area obtained by removing the peripheral end of the substrate 13 (the portion between the edge 13a of the substrate 13 and the conductor 12) from the upper surface area of the substrate 13. The coverage is measured using a scanning electron microscope (SEM), a transmission electron microscope (TEM), an optical microscope, etc.

As shown in FIG. 3 (B), the pattern of the conductor 12 is composed of a plurality of regions without the conductor 12 (herein, sometimes referred to as "first regions 12a") and the conductor 12 surrounding the first regions 12a. The first regions 12a may be filled with a portion of the bonding layer described below, or may be filled with a resin forming the conductive layer 16. The plurality of first regions 12a are formed in the same shape, which is a square in this embodiment, but may also be a rectangle. The plurality of first regions 12a of the same shape are arranged at a certain interval.

Describing the conductor 12 of this embodiment in more detail, the first region 12a is surrounded by a rectangular conductor 12 formed of two parallel first linear bodies 12A and two parallel second linear bodies 12B. The first linear bodies 12A and the second linear bodies 12B are orthogonal to each other.

There is a common linear body 12A and 12B between adjacent first regions 12a. The first linear body 12A and the second linear body 12B are electrically connected at the intersection. The width L6 of the linear body is preferably set to be not less than 0.05 μm and not more than 15 μm.

The maximum length L7 between the edges in the first region 12a, or the interval L8 between the adjacent first linear bodies 12A and the adjacent second linear bodies 12B is set to be greater than the wavelength of visible light and less than the wavelength of the radio wave reflected by the radio wave reflector 11. The maximum length of the side of the first region 12a is preferably set to be greater than 2 μm and less than 10 cm, more preferably greater than 20 μm and less than 1 cm, further preferably greater than 25 μm and less than 1 mm, further preferably greater than 30 μm and less than 250 μm. In this way, the maximum length L7 can be greater than the wavelength of visible light and less than the wavelength of the radio wave reflected by the radio wave reflector 11.

The thickness of the substrate 13 dominates the thickness (L2+L3) of the conductive layer 16. The thickness (L2+L3) of the conductive layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 0.3 μm or more. On the other hand, the upper limit of the thickness (L2+L3) of the conductive layer is preferably 20 μm or less, more preferably 15 μm or less, and further preferably 10 μm or less.

Furthermore, the details of the arrangement of the conductor 12 at the end of the radio wave reflector 11 will be described below.

(Variations of the pattern of the conductor 12)  The pattern of the conductor 12 is not limited to the lattice shape as in the embodiment, and may be, for example, a pattern as shown in FIGS. 5(A) to 5(E). For the purpose of illustration, FIGS. 5(A) to 5(E) only illustrate the conductor 12. The structure of the other conductors 12 is the same as that of FIG. 3(B).

In a variation, as shown in FIG. 5 (A), a brick-like pattern may be used. That is, a plurality of first linear bodies 12A are arranged in a straight line in the horizontal direction, and the first linear bodies 12A arranged in a straight line are arranged at intervals in the vertical direction. The second linear bodies 12B connect the first linear bodies 12A adjacent to each other in the vertical direction, but the second linear bodies 12B adjacent to each other in the vertical direction are staggered.

In a variation, as shown in FIG. 5 (B), a triangular pattern may be used. In this variation, as the plurality of regions without the conductive body 12, there are a first region 12a of a triangle and a second region 12b of an inverted triangle. The second region 12b is arranged between adjacent first regions 12a. The first region 12a and the second region 12b are respectively surrounded by a first linear body 12A, a second linear body 12B, and a third linear body 12C. The plurality of first regions 12a are arranged at certain intervals in the horizontal and vertical directions. In addition, the plurality of second regions 12b are also arranged at certain intervals in the horizontal and vertical directions. Moreover, the shapes formed by the first region 12a and the second region 12b are arranged in the same period.

Furthermore, each of the regions 12a and 12b is in the shape of an equilateral triangle, for example, it may also be an isosceles triangle or a triangle with three sides of different lengths.

In a variation, as shown in Fig. 5(C), the first region 12a may be a regular hexagonal region surrounded by a linear conductor 12. A plurality of first regions 12a are arranged at regular intervals in the longitudinal and transverse directions.

In a variation, as shown in FIG. 5 (D), it is also possible to have a plurality of regions without a conductor 12 of different shapes. That is, in a variation, as a region without a conductor 12, there are a first region 12a of a regular pentagon surrounded by a linear conductor 12, a second region 12b of an inverted regular pentagon, and a third region 12c of a rhombus. A plurality of first regions 12a are arranged at a certain interval in the horizontal and vertical directions. In addition, a plurality of second regions 12b are also arranged at a certain interval in the horizontal and vertical directions. In addition, a plurality of third regions 12c are also arranged at a certain interval in the horizontal and vertical directions. Moreover, the shapes formed by the first region 12a, the second region 12b, and the third region 12c are arranged in the same period.

In a variation, the pattern shown in FIG5(E) may be adopted. That is, as the region without the conductor 12, there may be a circular first region 12a surrounded by the linear conductor 12, a substantially triangular second region 12b, and a substantially inverted triangular third region 12c.

(Adhesive layer 14) The adhesive layer 14 is provided between the conductive layer 16 and the protective layer 15 to connect the conductive layer 16 and the protective layer 15. The adhesive layer 14 is preferably provided over the entire surface between the conductive layer 16 and the protective layer 15, but may be provided only in a portion between the conductive layer 16 and the protective layer 15. Examples of the adhesive layer 14 include synthetic resins, rubber adhesive sheets, and the like. Examples of synthetic resins include acrylic resins, silicone resins, polyvinyl alcohol resins, and the like. The adhesive layer 14 may be formed by filling a fluid adhesive between the conductive layer and the protective layer and curing the adhesive, or an adhesive sheet having an adhesive surface may be disposed between the conductive layer 16 and the protective layer 15 .

The thickness L4 of the bonding layer 14 is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. The upper limit of the thickness L4 of the bonding layer 14 is preferably 150 μm or less, more preferably 125 μm or less, and further preferably 100 μm or less.

Furthermore, the hydroxyl value of the bonding layer 14 is preferably 5 mgKOH/g or more, more preferably 8 mgKOH/g or more, further preferably 30 mgKOH/g or more, further preferably 90 mgKOH/g or more. On the other hand, the upper limit of the hydroxyl value of the bonding layer 14 is preferably 120 mgKOH/g or less. If the hydroxyl value of the bonding layer 14 is 5 mgKOH/g or more, there is an advantage that the bonding layer 14 is not easy to foam and/or turn white in a high temperature and high humidity environment. In this specification, the hydroxyl value is measured by the test method based on JIS K 1557.

Furthermore, the acid value of the bonding layer 14 is preferably 50 mgKOH/g or less, more preferably 45 mgKOH/g or less, further preferably 30 mgKOH/g or less, further preferably 10 mgKOH/g or less. On the other hand, the lower limit of the acid value of the bonding layer 14 is preferably 0.1 mgKOH/g or more. If the acid value of the bonding layer 14 is 50 mgKOH/g or less, corrosion of the conductor 12 can be prevented, and the stability of radio wave reflectivity over time can be improved. In this specification, the acid value is measured by the test method based on JIS K 2501.

The bonding layer 14 preferably does not contain an ultraviolet light inhibitor. If the bonding layer 14 does not contain an ultraviolet light inhibitor, it is easy to adjust the bonding layer 14 to be colorless and transparent. Here, "does not contain" includes not only the case where the bonding layer 14 does not contain an ultraviolet light inhibitor at all, but also includes the case where the bonding layer 14 contains a small amount to the extent that the bonding layer 14 does not damage the colorless and transparent state. The ultraviolet light inhibitor absorbs or scatters ultraviolet light to prevent the intrusion of ultraviolet light, and can be any of an ultraviolet light absorber and an ultraviolet light scatterer.

The bonding layer 14 is preferably made of a material having a dielectric loss tangent (tanδ) of 0.018 or less. The lower the dielectric loss tangent, the better. As the lower limit of the dielectric loss tangent, for example, 0.0001 or more can be listed. By using a bonding layer 14 having a dielectric loss tangent of 0.018 or less, the electric energy loss of the radio wave in the radio wave reflector 11 is reduced, and the reflection intensity can be further enhanced.

Furthermore, the synthetic resin material of the next layer 14 is preferably one whose relative dielectric constant changes according to the frequency of the electric field. The relative dielectric constant refers to the ratio of the dielectric constant of the medium (synthetic resin material in this embodiment) to the dielectric constant of a vacuum. By making the relative dielectric constant change according to the electric field, the intensity of the reflected wave in the electric field of a specific frequency can be increased. The relative dielectric constant preferably changes between 1.5 and 7, and more preferably changes between 1.8 and 6.5.

The bonding layer 14 is preferably made of a synthetic resin material with a dielectric loss tangent (tanδ) of 0.018 or less. The lower the dielectric loss tangent, the better, but it is usually above 0.0001. The dielectric loss tangent indicates the degree of electrical energy loss in a dielectric body. The larger the dielectric loss tangent, the greater the electrical energy loss. By using a bonding layer 14 with a dielectric loss tangent of 0.018 or less, the electrical energy loss of the radio wave in the radio wave reflector 11 is reduced, and the reflection intensity can be further enhanced.

(Protective layer 15) The protective layer 15 covers at least one side of the conductive layer 16 to protect the conductive layer 16. The protective layer 15 of the present embodiment has a size corresponding to the base material 13 when viewed from above. Examples of the protective layer 15 include a sheet (film) made of a synthetic resin. Examples of the synthetic resin include PET (polyethylene terephthalate), COP (cycloolefin polymer), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyoxymethylene, 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 preferably 20 μm or more, more preferably 38 μm or more, and further preferably 50 μm or more. On the other hand, the upper limit of the thickness L5 of the protective layer 15 is preferably 200 μm or less, and more preferably 150 μm or less.

When only the protective layer 15 is subjected to a pencil hardness test, the pencil hardness of the protective layer 15 when the surface load is 500 g is preferably "4B" or higher, more preferably "B" or higher, and further preferably "F" or higher. If the pencil hardness of only the protective layer 15 is "4B" or higher, the conductor 12 can be protected. Furthermore, if the pencil hardness of only the protective layer 15 is "F" or higher, the conductor 12 can be protected more firmly.

The moisture permeability of the protective layer 15 at a temperature of 40°C and a humidity of 90% rh (relative humidity) is preferably 20 g/m ²・24 h or less, more preferably 16 g/m ²・24 h or less, further preferably 12 g/m ²・24 h or less, and further preferably 10 g/m ²・24 h or less. If the moisture permeability of the protective layer 15 at a temperature of 40°C and a humidity of 90% rh (relative humidity) is 20 g/m ²・24 h or less, the conductive layer 16 is not easily corroded and the surface resistivity of the conductive layer 16 is not easily increased. The "moisture permeability" described in this specification is measured by the test method based on JIS Z 0208 (1976).

The protective layer 15 is preferably flexible. The longitudinal elastic modulus of the protective layer 15 is preferably 1 GPa or more, more preferably 1.2 GPa or more, and further preferably 1.5 GPa or more. On the other hand, the upper limit of the longitudinal elastic modulus of the protective layer 15 is preferably 4 GPa or less, more preferably 3.8 GPa or less, and further preferably 3.5 GPa or less.

The protective layer 15 may be subjected to an anti-glare treatment or an anti-reflection treatment. For example, when the protective layer 15 is formed of a film, at least one of the upper surface (surface) and the lower surface (the surface opposite to the bonding layer 14) of the film may be subjected to an anti-glare treatment or an anti-reflection treatment.

The anti-glare treatment means a treatment in which a concave-convex shape is formed on at least one surface of the protective layer 15 to scatter light and suppress the reflection of the light source such as lighting into the protective layer 15. Examples of methods for implementing the anti-glare treatment include a method of applying a binder resin in which fine particles are dispersed on the surface of the film, sandblasting, chemical etching, and the like.

The anti-reflection treatment means the following treatment: an anti-reflection film is formed on at least one side of the protective layer 15, and the reflected light reflected from the surface of the anti-reflection film and the reflected light reflected from the interface between the anti-reflection film and the thin film are attenuated by interference, thereby suppressing the reflection of the light source such as the lighting. The anti-reflection film can be a single layer or a film formed by alternately stacking thin films with different refractive indices.

The protective layer 15 may also be formed by attaching an anti-glare or anti-reflection film to one or both sides of a synthetic resin film.

The protective layer 15 may contain an ultraviolet light preventer, or may be subjected to an ultraviolet light blocking treatment on the upper surface (surface) of the protective layer 15, or may contain an ultraviolet light preventer and be subjected to an ultraviolet light blocking treatment. The ultraviolet light blocking treatment means a treatment of forming a film containing an ultraviolet light preventer by coating or the like. According to this structure, ultraviolet light is not easy to penetrate into the inside of the radio wave reflector 11, so even when the radio wave reflector 11 is used for a long time, the discoloration of the radio wave reflector 11 caused by ultraviolet light can be suppressed. As described above, the ultraviolet light preventer may be any of an ultraviolet light absorber and an ultraviolet light scatterer. Examples of the ultraviolet absorber include ethylhexyl methoxycinnamate, tert-butylmethoxydiphenylmethane, and dimethyl PABA octyl ester, and examples of the ultraviolet scatterer include titanium oxide and zinc oxide, but are not limited thereto.

(Construction of the end portion of the radio wave reflector 11) The construction of the peripheral end portion of the radio wave reflector 11 is described in detail. All the conductors 12 constituting the conductive layer 16 are formed on the upper surface of the substrate 13. The conductor 12 is preferably arranged at an inner side at least 5 mm away from the end portion of the laminate 18. The end portion of the laminate 18 means the end portion 13a of the substrate 13 which is a part of the laminate 18. When the substrate 13 is the same size as the protective layer 15 and the bonding layer 14, it may also be referred to as the respective ends of the protective layer 15 and the bonding layer 14. As shown in FIG4 , it is preferred that the distance L11 between an arbitrary position P1 of the edge of the laminate 18 (the edge 13a of the substrate 13) and the conductor 12 closest to the arbitrary position P1 be set to be 5 mm or more when viewed from above. When viewed from above, the conductor 12 is covered by a retaining layer such as the substrate 13, the bonding layer 14, and the protective layer 15.

Furthermore, since the conductor 12 is not disposed at the end of the laminate 18, the end of the laminate 18 has a structure in which the bonding layer 14 and the protective layer 15 are laminated on the upper surface of the substrate 13. Therefore, when viewed from the side, the conductor 12 is covered by these layers. Therefore, the conductor 12 of this embodiment is not exposed to the outside.

That is, the conductor 12 “is not exposed to the outside” means that the conductor 12 is covered by a retaining layer such as the base material 13, the adhesive layer 14, and the protective layer 15 in a plan view or a side view.

As shown in the present embodiment, when the radio wave reflector 11 is composed of a laminate 18 and does not have the sealing material 17 described below, "not exposed to the outside" means that the conductor 12 is arranged closer to the inside than the end edge of the laminate 18 (the end edge 13a of the substrate 13) and is covered by the substrate 13, the bonding layer 14, the protective layer 15 and other retaining layers when viewed from above or from the side.

Generally, the radio wave reflector 11 deteriorates due to discoloration, corrosion, etc. caused by the environmental influence of the conductor 12. According to the above configuration, since the conductor 12 is not exposed to the outside, the conductor 12 is not easily affected by the environment, and the deterioration of the radio wave reflector 11 is prevented, and durability can be achieved.

(Variations of the structure of the end of the radio wave reflector 11)  Variations of the structure of the end are shown in FIG. 7 (A) and FIG. 7 (B). The radio wave reflector 11 of the present embodiment is provided with a sealing material 17 covering the side of the laminate 18 around the laminate 18 and at least at a position corresponding to the conductor 12 constituting the conductive layer 16. The sealing material 17 only needs to cover the side of the laminate 18 in a manner that at least the conductor 12 is not exposed to the outside when the radio wave reflector 11 is viewed from the side. As shown in FIG. 7 (B), the sealing material 17 can cover the side of each of the substrate 13, the conductive layer 16, the bonding layer 14, and the protective layer 15. The sealing material 17 has adhesion and is bonded to the side of each layer.

In this embodiment, the conductor 12 may be disposed on the substrate 13 and at a position that is consistent with the edge 13a of the substrate 13 when viewed from above, or may be disposed continuously along the edge 13a of the substrate 13. That is, when viewed from above, the distance L11 between an arbitrary position P1 of the edge of the laminate 18 (the edge 13a of the substrate 13) and the conductor 12 closest to the arbitrary position P1 may be 0.

In a plan view, the conductor 12 is arranged at least by the amount of the sealing material 17, and is located closer to the inner side than the edge of the radio wave reflector 11. The sealing material 17 is in contact with at least the side surface of the conductor 12 to prevent the conductor 12 from being exposed to the outside. The sealing material 17 makes the conductor 12 less susceptible to environmental influences, and the radio wave reflector 11 is prevented from deteriorating, thereby achieving durability.

Furthermore, the conductor 12 may be formed further inwardly than the edge 13a of the substrate 13. In this case, the conductor 12 is not only further inwardly than the edge 13a of the substrate 13, but also less susceptible to environmental influences due to the sealant 17, and deterioration is prevented, thereby achieving durability.

Furthermore, the conductor 12 may be formed further inwardly than the edge 13a of the substrate 13. In this case, the conductor 12 is not only further inwardly than the edge 13a of the substrate 13, but also less susceptible to environmental influences due to the sealant 17, and deterioration is prevented, thereby achieving durability.

That is, in the present embodiment shown in FIG. 7 , the conductor 12 “is not exposed to the outside” means that the conductor 12 is covered by the sealing material 17 when the radio wave reflector 11 is viewed from the side, and the conductor 12 is covered by the base material 13 , the adhesive layer 14 , and the protective layer 15 when viewed from above.

In a plan view, the length L12 of the sealant 17 protruding from the laminate 18 (the width of the sealant 17) is fixed and preferably 0.01 mm to 10 mm. The length L10 of one side of the radio wave reflector 11 is the length L13 of one side of the laminate 18 plus twice the protruding length L12 of the sealant 17.

As the sealing material 17, a synthetic resin can be used. Examples of the synthetic resin include silicone resin, epoxy resin, polyester resin, acrylic resin, urethane resin, polyimide resin, polyvinyl chloride resin, nylon resin, and the like.

The other structures and functions are the same as those of the embodiments shown in FIGS. 2 to 4 , and thus the corresponding structures are labeled with the same symbols and detailed descriptions are omitted.

(Manufacturing method of radio wave reflector 11 in the embodiment in which sealing material 17 is provided)  The radio wave reflector 11 in the embodiment shown in FIG7 can be installed on a wall or other installation location after the radio wave reflector 11 is manufactured. The manufacturing method of the radio wave reflector 11 is as follows. First, a step of forming a laminate 18 is performed. In this step, a conductive layer 16 is formed on the upper surface of the substrate 13, and a protective layer 15 is connected to the conductive layer 16 via a bonding layer 14, thereby forming a laminate 18. Next, a step of providing a sealing material 17 is performed. In this step, a sealing material 17 is provided at a position around the laminate 18 at least corresponding to the conductive layer 16 so as to prevent the conductor 12 from being exposed. The sealing material 17 has adhesiveness and can therefore be mounted on the side surface of the laminate 18. Through these steps, the radio wave reflector 11 of the embodiment shown in FIG. 7 is manufactured.

Alternatively, the step of providing the sealing material 17 may be performed first, and then the step of forming the laminate 18 may be performed. In the step of providing the sealing material 17, the sealing material 17 is arranged in a ring shape on the surface of a release paper or the like. The space surrounded by the sealing material 17 has the same shape and size as the laminate 18 when viewed from above. Then, the step of forming the laminate 18 is performed as described above. Then, the step of embedding the laminate 18 into the space surrounded by the sealing material 17 is performed. Thus, the radio wave reflector 11 is manufactured. In the radio wave reflector 11 manufactured in this way, the sealing material 17 is located at a position around the laminate 18 at least corresponding to the conductive layer 16.

(Construction method of radio wave reflector 11 in implementation mode of installing sealing material 17)  The radio wave reflector 11 in the implementation mode shown in FIG7 can be installed at the installation location of the installation surface such as the wall in the following construction method. The installation location is, for example, the surface of the wall, partition, column, cross-block ("duck house" in Japanese), the outer wall of the building, window, etc., which can be a flat surface or a curved surface. First, the step of installing the multilayer body 18 at the installation location is performed. In this step, the multilayer body 18 is installed at the installation location in a manner that the base material 13 is connected to the installation location, using installation means such as double-sided tape or adhesive. Then, the step of installing the sealing material 17 is performed. In this step, a sealing material 17 is provided around the laminate 18 at least at a position corresponding to the conductive layer 16 so as to prevent the conductive body 12 from being exposed.

Alternatively, the step of installing the sealing material 17 may be performed first, and then the step of installing the laminate 18 at the installation location may be performed. First, the sealing material 17 is installed in a ring shape around the installation location of the laminate 18 on the installation surface such as a wall. Then, the laminate 18 is installed at the installation location in a manner of being embedded in the space surrounded by the sealing material 17. In this way, the radio wave reflector 11 is constructed at the installation location.

In the embodiment shown in FIG. 7 , the radio wave reflector 11 has one laminate 18, but the radio wave reflector 11 may also be provided with a plurality of laminates 18 spaced apart. In the example of FIG. 8 , four laminates 18 are provided. In a plan view, a sealing material 17 is provided on the side where no adjacent laminate 18 exists among the four sides of each laminate 18, and the sealing material 17 is filled in the entire space between the adjacent laminates 18. In this way, the sealing material 17 is arranged around each laminate 18. The construction method of this radio wave reflector 11 is as follows. First, the following step is performed, that is, a plurality of laminates 18 are installed at intervals on a wall or other installation location using installation means such as double-sided tape or adhesive. Then, the step of installing the sealing material 17 is performed. In this step, the sealing material 17 is installed at least at the position corresponding to the conductive layer of the side of the four sides of the laminate 18 where there is no adjacent laminate 18. Then, the sealing material 17 is installed in the entire space between the adjacent laminates 18. In this way, the radio wave reflector 11 is constructed to the installation location. Alternatively, the step of installing the sealing material 17 may be performed first, and then the step of installing the laminate 18 at the installation location is performed. First, a sealing material 17 is placed in a ring shape around the predetermined installation position of the plurality of laminates 18. Then, when the plurality of laminates 18 are installed at intervals at the installation position, a sealing material is placed in the space between adjacent laminates 18. Then, the laminates 18 are installed at the installation position in a manner of being embedded in the space surrounded by the sealing material 17.

(Usage) The radio wave reflector 11 of the above-mentioned embodiment can be attached to the surfaces of the walls, partitions, columns, baffles, outer walls of buildings, windows, etc. of the buildings as the installation locations by using adhesives, etc. In addition, it can also be used as interior decoration paper or decorative material, for example. The inner layer of paper is a paper material installed on the inner surface of the interior decoration material. As interior decoration materials, for example: inner walls, ceilings, partitions, floor materials, etc. can be listed. As decorative materials, for example: posters, decorative stickers, stained glass style stickers, etc. can be listed. Decorative materials can be listed: wall materials, floor materials, doors, lighting covers, door lintels ("railway" in Japanese), columns, televisions, top boards of tables, etc. FIG. 6 shows an example in which a poster as a decorative material 30A is installed on a wall, and a decorative material 30B is installed on a lighting cover.

By installing the decorative materials 30A and 30B including the radio wave reflector 11 on indoor equipment or building materials, the radio waves entering the room from the outside through the window 33 are reflected at the decorative materials 30A and 30B. In this way, the radio waves reach a wider range of the indoor space S, and the convenience of radio wave reception is improved.

Furthermore, the radio wave reflector 11 is not limited to being used as wallpaper, and can also be used as printed paper for printing plywood. In this case, the plywood including the radio wave reflector 11 can be used to form doors, walls, partitions, exterior wall materials, roofs, ceilings, floor panels, baseboards, etc.

Furthermore, the radio wave reflector 11 is not limited to a flat plate, but can also be a spherical surface. For example, FIG. 6 (B) is a diagram obtained by observing the interior of a room from a top view. The building material 30 having the radio wave reflector 11 on the surface is a spherical corner column 30C at the corner of the house. The radio waves entering from the window 33 are reflected at the corner column 30C, and the radio waves are expanded in a wider range in the indoor space S. Furthermore, FIG. 6 (A) and FIG. 6 (B) are only schematic diagrams showing the outgoing waves, and do not represent the actual reflection range of the radio waves.

<Evaluation Test A> Regarding the radio wave reflector 11, Examples 1 to 13 and Comparative Examples 1 to 8 were prepared, and evaluation tests were conducted on pencil hardness test, adhesion of the protective layer to the adhered layer, radio wave reflectivity, total light transmittance, haze, surface resistivity, foaming, whitening, yellowing degree Δb*, etc. However, the radio wave reflector 11 of the present invention is not limited to Examples 1 to 13.

(Description of Examples and Comparative Examples) In Examples 1 to 13 and Comparative Examples 1 to 8, test pieces were prepared in the following manner. 1 part of a crosslinking agent was added to 100 parts of the following adhesive, and the mixture was stirred for 3 minutes to obtain an adhesive composition. Subsequently, a protective layer was laid on a coating table, the adhesive composition was dripped, and a coating machine adjusted to a thickness of 25 μm was started to obtain an adhesive layer. It was dried at a temperature of 110°C for 5 minutes, and then heated and aged at 40°C for 48 hours to obtain a protective layer and an adhesive layer of the test piece.

Then, the conductive layer, the previously prepared protective layer and the bonding layer were vacuum-laminated at 40° C. for 6 minutes to obtain a test piece. In addition, in the following conditions, for the test piece without the bonding layer and the protective layer, the step of obtaining the protective layer and the bonding layer was not performed.

(1) Example 1 As Example 1, the conditions for the test piece are as follows.・Conductive layer Shape: Square with a side length of 20 cm Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm (the grid pattern means a grid pattern in which the area 12a without a conductor surrounded by the conductor 12 is a square (the pattern of the conductor 12 shown in Figure 3 (B)); the grid spacing means the interval L8 between adjacent parallel conductors 12 in the above grid pattern) ・Adhesive layer Adhesive: X313-295S-14 (manufactured by SAIDEN CHEMICAL INDUSTRY) Acid value: 0.8 mgKOH/g Hydroxyl value: 115 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(2) Example 2 As Example 2, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(3) Example 3 As Example 3, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2006HE (manufactured by Soken Chemical) Acid value: 30 mgKOH/g Hydroxyl value: 10 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(4) Example 4 As Example 4, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2137KH (manufactured by Soken Chemical Co., Ltd.) Acid value: 10 mgKOH/g Hydroxyl value: 8.0 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(5) Example 5 As Example 5, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 75 μm Pencil hardness test (protective layer only): F Moisture permeability: 8.0 g/ ^m2・24 h

(6) Example 6 As Example 6, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 50 μm Pencil hardness test (protective layer only): F Moisture permeability: 12 g/ ^m2・24 h

(7) Example 7 As Example 7, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 45 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(8) Example 8 As Example 8, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 1604N (manufactured by Soken Chemical Co., Ltd.) Acid value: 45 mgKOH/g Hydroxyl value: 6.6 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(9) Example 9 As Example 9, the conditions for the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 1502C (manufactured by Soken Chemical) Acid value: 0.1 mgKOH/g Hydroxyl value: 8.8 mgKOH/g Crosslinking agent: E-AX (manufactured by Soken Chemical) Epoxy type ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(10) Example 10 As Example 10, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2147 (manufactured by Soken Chemical Co., Ltd.) Acid value: 4.0 mgKOH/g Hydroxyl value: 32 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 125 μm Pencil hardness test (protective layer only): F Moisture permeability: 4.8 g/ ^m2・24 h

(11) Example 11 As Example 11, the conditions for the test piece were as follows.・Conductive layer Shape: Square with a side length of 20 cm Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical) Isocyanate type ・Protective layer Material: PET sheet (KB125N05 manufactured by KIMOTO) Thickness: 125 μm Pencil hardness test (protective layer only): 3H Moisture permeability: 4.8 g/m ²・24 h

(12) Example 12 As Example 12, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 38 μm Pencil hardness test (protective layer only): F Moisture permeability: 16 g/ ^m2・24 h

(13) Example 13 As Example 13, the conditions for the test piece were as follows.・Conductive layer Shape: Square with a side length of 20 cm Material: PET sheet Conductor: Grid-shaped, circular pattern composed of copper (Cu) with a line width of 2.3 μm, a line thickness of 1.6 μm, and a grid spacing of 100 μm (the grid-shaped, circular pattern means that the shape of the area 12a without a conductor surrounded by the conductor 12 includes a square pattern and a circular pattern, which means the pattern shown in the following variation 4 (Figure 12); the grid spacing means the interval L8 between the adjacent parallel conductors 12 (the first surrounding portion 41 in Figure 12) surrounding the square area 12a; the diameter of the conductor 12 arranged in a circle (the second surrounding portion 51 in Figure 12) is equal to the grid spacing) ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical) Isocyanate-based Protective layer Material: PET sheet (Toyobo Ester Film HB3UO) Thickness: 50 μm Pencil hardness test (protective layer only): 3H Moisture permeability: 4.8 g/ ^m2・24 h

(14) Comparative Example 1 As Comparative Example 1, the conditions of the test piece are as follows.   ・Conductive layer  Shape: Square with a side length of 20 cm  Material: PET sheet  Conductive body: Grid pattern composed of silver (Ag) Line width 0.8 μm, line thickness 0.5 μm, grid spacing 30 μm  ・Adhesive layer, protective layer  None

(15) Comparative Example 2 As Comparative Example 2, the conditions of the test piece are as follows.   ・Conductive layer  Shape: Square with one side of 20 cm  Material: PET sheet  Conductive body: Grid pattern composed of silver (Ag) Line width 0.8 μm, line thickness 0.5 μm, grid spacing 45 μm  ・Adhesive layer, protective layer  None

(16) Comparative Example 3 As Comparative Example 3, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 38 μm Pencil hardness test (protective layer only): F Moisture permeability: 16 g/ ^m2・24 h

(17) Comparative Example 4 As Comparative Example 4, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 38 μm Pencil hardness test (protective layer only): F Moisture permeability: 16 g/ ^m2・24 h

(18) Comparative Example 5 As Comparative Example 5, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 25 μm Pencil hardness test (protective layer only): F Moisture permeability: 24 g/ ^m2・24 h

(19) Comparative Example 6 As Comparative Example 6, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PET sheet Thickness: 25 μm Pencil hardness test (protective layer only): F Moisture permeability: 24 g/ ^m2・24 h

(20) Comparative Example 7 As Comparative Example 7, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: PP sheet Thickness: 50 μm Pencil hardness test (protective layer only): B Moisture permeability: 4.5 g/ ^m2・24 h

(21) Comparative Example 8 As Comparative Example 8, the conditions of the test piece are as follows. ・Conductive layer Shape: Square with a length of 20 cm on one side Material: PET sheet Conductor: Grid pattern composed of silver (Ag) with a line width of 0.8 μm, a line thickness of 0.5 μm, and a grid spacing of 30 μm ・Adhesive layer Adhesive: 2980 (manufactured by Soken Chemical Co., Ltd.) Acid value: 0.5 mgKOH/g Hydroxyl value: 95 mgKOH/g Crosslinking agent: L-45K (manufactured by Soken Chemical Co., Ltd.) Isocyanate-based ・Protective layer Material: LDPE sheet Thickness: 50 μm Pencil hardness test (protective layer only): 4B Moisture permeability: 10 g/ ^m2・24 h

(Measurement method) (1) Determination of moisture permeability of protective layer. Place the protective layer in a measuring device and place it in an environment with a temperature of 40℃ and a humidity of 90%rh for 48 hours. After supplying water vapor from one side, measure the amount of water that passes through to obtain the moisture permeability.

(2) Adhesion force measurement: The adhesive layer and the protective layer were attached to a PET film with a thickness of 188 μm and cut into 25 mm squares. The film was pulled at 180 degrees relative to the PET film using an autograph at a speed of 300 mm/min to obtain the above-mentioned adhesion force.

(3) Evaluation of radio wave reflectivity For incident waves of 4.7 GHz and 28 GHz, the reception intensity was measured while changing the incident angle and reflection angle, and the evaluation was performed by comparing it with the reception intensity of the aluminum plate. The reception intensity was evaluated as "◎" when it was equal to that of the aluminum plate, "○" when the difference with the reception intensity of the aluminum plate was more than -10 dB but less than -20 dB, and "×" when the difference with the reception intensity of the aluminum plate was more than -20 dB.

(4) Total light transmittance and haze measurement: The test piece was cut into 5 cm squares and the total light transmittance and haze were measured using a fog meter HM-150 (manufactured by Murakami Color Technology Laboratory Co., Ltd.) in accordance with the measurement method of JIS-K7136:2000.

(5) Surface resistivity: The surface resistivity was obtained by subjecting each test piece to the following (7) heat and moisture resistance test and then measuring it using EC-80P manufactured by Napson.

(6) Pencil hardness test method: According to JIS K 5600-5-4, a load of 500±10 g is applied to confirm the hardness of the grid pattern of the conductor when it is deformed. The hardness that is one level lower is taken as the hardness.

(7) Heat and humidity resistance test method: Place the test piece in a constant temperature and humidity tank adjusted to 60°C and 95%RH for 500 hours, then take out the test piece and place it at room temperature for 4 hours, then visually check for bubbling and whitening. Then, perform the above (2) adhesion measurement, (3) evaluation of radio wave reflectivity, (4) transmittance measurement, and haze measurement again, and compare before (initial) and after the heat and humidity resistance test. Regarding adhesion, calculate the ratio of the adhesion after the heat and humidity resistance test to the adhesion before (initial) the heat and humidity resistance test (initial ratio).

(8) Lightfastness Test Place the test piece in a xenon lamp weathering light aging tester Ci4000 manufactured by ATLAS, and set the chamber to an irradiance of 60 W/m ² (300-400 nm), a black standard temperature (BST) of 65±3°C, a humidity of 50±5%RH, and a chamber temperature of 38°C. Measure the yellowing degree Δb* before and after 1300 hours of exposure (one year of direct sunlight). Then, perform the above (3) evaluation of radio wave reflectivity, (4) transmittance measurement, and haze measurement again, and compare the results before (initial) and after the lightfastness test.

(Test Results) The test results of the embodiment are shown in Table 1-1 and Table 1-2, and the test results of the comparative example are shown in Table 2. [Table 1-1] Pencil hardness Moisture permeability Acid value Hydroxyl value Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Conductive layer Grid spacing 30 μm ● ● ● ● ● ● 45 μm 100 μm Line width 0.8 μm ● ● ● ● ● ● 2.3 μm Line Thickness 0.5 μm ● ● ● ● ● ● 1.6 μm Metal Type Ag ● ● ● ● ● ● Cu Protective layer PET Thickness: 125 μm F 4.8 ● ● ● ● 3H 75 F 8.0 ● 50 F 12 ● 3H 4.8 38 F 16 25 F twenty four PP 50 B 4.5 LDPE 50 4B 10 Next layer Follow-up agent X313-295S-14 0.8 115 ● 2980 0.5 95 ● ● ● 2006HE 30 10 ● 2137KH 10 8.0 ● 1604N 45 6.6 1502C 0.1 8.8 2147 4.0 32 Crosslinking agent L-45K ● ● ● ● ● ● E-AX Reviews Follow-up initial 12.8 10.4 15.3 6.1 10.4 10.4 After heat and moisture resistance test 24.5 12.6 14.8 13.1 12.6 12.6 Initial ratio 1.9 1.2 1.0 2.1 1.2 1.2 Radio wave reflectivity initial ◎ ◎ ◎ ◎ ◎ ◎ After heat and moisture resistance test ◎ ◎ ◎ ◎ ◎ ◎ After light fastness test ◎ ◎ ◎ ◎ ◎ ◎ Penetration initial 90 90 90 90 90 90 After heat and moisture resistance test 90 90 90 90 90 90 After light fastness test 89 89 89 89 89 89 Fog initial 1 1 1 1 1 1 After heat and moisture resistance test 1 1 1 1 1 1 After light fastness test 2 1 1 1 1 1 Surface resistivity 3.1 3.8 3.4 3.2 3.8 3.8 Pencil hardness test 4H 4H 4H 4H 4H 4H Heat and moisture resistance test Foaming without without without without without without Whitening without without without without without without Light fastness test Yellowing Δb* 4.1 4.8 5.1 5.3 4.8 4.8 [Table 1-2] Pencil hardness Moisture permeability Acid value Hydroxyl value Embodiment 7 Embodiment 8 Embodiment 9 Embodiment 10 Embodiment 11 Embodiment 12 Embodiment 13 Conductive layer Grid spacing 30 μm ● ● ● ● ● 45 μm ● 100 μm ● Line width 0.8 μm ● ● ● ● ● ● 2.3 μm ● Line Thickness 0.5 μm ● ● ● ● ● ● 1.6 μm ● Metal Type Ag ● ● ● ● ● ● Cu ● Protective layer PET Thickness: 125 μm F 4.8 ● ● ● ● 3H ● 75 F 8.0 50 F 12 3H 4.8 ● 38 F 16 ● 25 F twenty four PP 50 B 4.5 LDPE 50 4B 10 Next layer Follow-up agent X313-295S-14 0.8 115 2980 0.5 95 ● ● ● ● 2006HE 30 10 2137KH 10 8.0 1604N 45 6.6 ● 1502C 0.1 8.8 ● 2147 4.0 32 ● Crosslinking agent L-45K ● ● ● ● ● ● E-AX ● Reviews Follow-up initial 10.4 19.3 11.1 7.6 10.4 10.4 10.4 After heat and moisture resistance test 12.6 22.7 10.1 14.6 12.6 12.6 12.6 Initial ratio 1.2 1.2 0.9 1.9 1.2 1.2 1.2 Radio wave reflectivity initial ◎ ◎ ◎ ◎ ◎ ◎ ◎ After heat and moisture resistance test ◎ ◎ ◎ ◎ ◎ ◎ ◎ After light fastness test ◎ ◎ ◎ ◎ ◎ ◎ ◎ Penetration initial 90 90 88 90 90 90 78 After heat and moisture resistance test 90 90 88 89 90 90 78 After light fastness test 89 87 85 86 89 89 78 Fog initial 1 1 8 1 1 1 5 After heat and moisture resistance test 1 1 8 8 1 1 5 After light fastness test 1 4 twenty four 3 1 1 5 Surface resistivity 3.8 3.5 3.6 3.7 3.8 3.8 0.7 Pencil hardness test 4H 4H 4H 4H 4H 4H 4H Heat and moisture resistance test Foaming without without without without without without without Whitening without without without without without without without Light fastness test Yellowing Δb* 4.8 5.7 10.4 5.3 4.8 4.8 2.3 [Table 2] Pencil hardness Moisture permeability Acid value Hydroxyl value Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Comparison Example 5 Comparative Example 6 Comparison Example 7 Comparative Example 8 Conductive layer Grid spacing 30 μm ● ● ● ● ● ● ● 45 μm ● 100 μm Line width 0.8 μm ● ● ● ● ● ● ● ● 2.3 μm Line Thickness 0.5 μm ● ● ● ● ● ● ● ● 1.6 μm Metal Type Ag ● ● ● ● ● ● Cu Protective layer PET Thickness: 125 μm F 4.8 3H 75 F 8.0 50 F 12 3H 4.8 38 F 16 ● ● 25 F twenty four ● ● PP 50 B 4.5 ● LDPE 50 4B 10 ● Next layer Follow-up agent X313-295S-14 0.8 115 2980 0.5 95 ● ● ● ● ● ● 2006HE 30 10 2137KH 10 8.0 1604N 45 6.6 1502C 0.1 8.8 2147 4.0 32 Crosslinking agent L-45K ● ● ● ● ● ● E-AX Reviews Follow-up initial - - 10.4 10.4 10.4 10.4 10.4 10.4 After heat and moisture resistance test - - 12.6 12.6 12.6 12.6 12.6 12.6 Initial ratio - - 1.2 1.2 1.2 1.2 1.2 1.2 Radio wave reflectivity initial × × × × × × × × After heat and moisture resistance test × × × × × × × × After light fastness test × × × × × × × × Penetration initial 90 90 90 90 90 90 90 90 After heat and moisture resistance test - - - - - - - - After light fastness test - - - - - - - - Fog initial - - - - - - - - After heat and moisture resistance test - - - - - - - - After light fastness test - - - - - - - - Surface resistivity 214 221 - - - - - - Pencil hardness test 6B 6B B B B B 2B 5B Heat and moisture resistance test Foaming - - without without without without without without Whitening - - without without without without without without Light fastness test Yellowing Δb* - - - - - - - -

As can be seen from Table 1-1, Table 1-2, and Table 2, the pencil hardness test of the test piece of Examples 1 to 13 is "4H", while that of Comparative Examples 1 to 8 is "6B", "B", "2B", and "5B". At this time, the evaluation of the radio wave reflectivity of Examples 1 to 13 is "◎", while that of Comparative Examples 1 to 8 is "×".

From this result, it can be seen that the evaluation of radio wave reflectivity depends on the hardness of the protective layer. Therefore, it can be seen that in order to maintain good radio wave reflectivity, it is also necessary to select an appropriate hardness of the protective layer. In addition, regarding Comparative Examples 1 and 2, since the surface resistivity shows a higher value and the radio wave reflectivity is "×", when the surface resistivity shows a higher value, it can be seen that the protective layer has peeled off, deformed, or damaged. In this case, it can also be seen that the radio wave reflectivity has deteriorated.

In summary, it can be seen that Examples 1 to 13 can protect the conductor without damaging the radio wave reflectivity because the pencil hardness test is "F" or above, and thus can obtain practical radio wave reflectivity.

In Examples 1 to 13, the radio wave reflectivity was evaluated as "◎" after the heat and moisture resistance test and the light resistance test, and the radio wave reflectivity was not impaired. In addition, after the tests, the haze was less than 30%, the total light transmittance was 70% or more, and transparency was maintained. Furthermore, in Examples 1 to 13, the yellowing degree after the light resistance test was less than 15, and the color was not seriously changed, and it was not easy to deteriorate.

<Evaluation Test B> Examples 21 to 26 and Comparative Example 21 were prepared as radio wave reflectors 11, and the difference in yellowness index, the rate of change r of surface resistivity during heat and moisture resistance tests, and the difference in reflection intensity between Examples 21 to 26 and Comparative Example 1 were evaluated. However, the radio wave reflector 11 of the present invention is not limited to Examples 21 to 26.

(Description of embodiments and comparative examples) (Embodiment 21) The radio wave reflector 11 manufactured as Embodiment 21 is a radio wave reflector 11 having the same structure as the embodiments shown in Figures 2 to 4. The plane shape of the radio wave reflector 11 is a square, the length L10 of one side is set to 20 cm, and the thickness L1 of the radio wave reflector 11 is set to 250 μm.

The radio wave reflection intensity of the radio wave reflector 11 in the frequency band of 3 GHz to 300 GHz is not less than -30 dB. Furthermore, the maximum value of the radio wave reflection intensity when the radio wave reflector 11 reflects incident waves of frequencies of 3 GHz to 300 GHz (hereinafter also referred to as "the maximum value of the radio wave reflection intensity") is -20 dB.

A synthetic resin material sheet made of PET (manufactured by TORAY, Lumirror 50T60) was used as the substrate 13, and the thickness L2 of the substrate 13 was set to 50 μm.

The conductor 12 of the conductive layer 16 is a linear metal thin film composed of silver (Ag), and the thickness (film thickness) L3 is set to 500 nm, the line width L6 is set to 0.5 μm, and the length L7 between adjacent conductors 12 is set to 60 μm. The surface resistivity of the conductive layer 16 is 1.7 Ω/□, and the conductor coverage is 3.3%. The distance L11 between the end 13a of the substrate 13 of the laminate 18 (i.e., the end of the protective layer 15) and the conductor 12 is set to 10 mm.

A rubber adhesive is used as the adhesive layer 14. Specifically, the next layer 14 is obtained by adding 100 parts by weight of a rubber polymer (a mixture of 50% by weight of styrene-(ethylene-propylene)-styrene type block copolymer and 50% by weight of styrene-(ethylene-propylene) type block copolymer, 15% by weight of styrene content, and weight average molecular weight of 130,000), 40 parts by weight of a synthetic resin (FMR-0150 manufactured by Mitsui Chemicals, Inc.), 20 parts by weight of a softener (LV-100 manufactured by JX Nippon Mining & Petrochemicals, Ltd.), 0.5 parts by weight of an antioxidant (Adekastab AO-330 manufactured by ADEKA Corporation), and 150 parts by weight of toluene to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, a dropping funnel, and a stirring device, and stirring at 40°C for 5 hours. The thickness L4 of the bonding layer 14 is set to 150 μm. The dielectric loss tangent of the bonding layer 14 is set to 0.04.

A synthetic resin sheet made of PET (manufactured by TORAY, Lumirror 50T60) was used as the protective layer 15. The thickness L5 of the protective layer 15 was set to 50 μm.

In Example 21, the sealing material 17 is not provided. Furthermore, the thickness L1 of the radio wave reflector 11, the thickness L3 of the conductor 12, the thickness L2 of the substrate 13, the thickness L4 of the bonding layer 14, and the thickness L5 of the protective layer 15 are obtained by measuring any plurality of locations and calculating the average value of the obtained measured values. When measuring the thicknesses L1 to L5, for example, a reflectivity spectroscopic film thickness measuring device (for example, F3-CS-NIR manufactured by FILMETRICS Co., Ltd.) is used as a measuring device.

The manufacturing method of the radio wave reflector 11 of Example 21 is explained. First, the conductor 12 is formed on the substrate 13. On one surface of a copper foil with a thickness of 5 to 200 μm having sufficient strength as a metal layer, a core layer of 0.01 to 3 μm is formed by electrolysis or electroless plating. Then, on the surface of the core layer, a conductor 12 with a specific configuration pattern is formed by electrolysis or electroless plating. Then, the entire conductor 12 is covered with the substrate 13. An adhesive is pre-coated on the substrate 13. Then, the copper foil and the core layer are etched away. In this way, the conductor 12 is formed on the substrate 13.

Then, the protective layer 15 is installed on the opposite side of the substrate 13 via the conductor 12 using the adhesive layer 14. The protective layer 15 is attached to the conductor 12 of the substrate 13 using the adhesive layer 14 so that air bubbles do not enter. In this way, the radio wave reflector 11 is manufactured.

(Example 22) The difference between the radio wave reflector 11 manufactured as Example 22 and Example 21 is that the distance L11 between the edge of the substrate 13 of the laminate 18 and the conductor 12 is set to 5 mm. The other structures are the same as those of Example 21.

(Example 23) The radio wave reflector 11 manufactured as Example 23 is different from Examples 21 and 22 in that it has the same structure as the embodiment shown in FIG7 . A sealing material 17 is provided around the laminate 18, and the length L12 of the sealing material 17 protruding from the laminate 18 (the width of the sealing material 17) is 5 mm. As the sealing material 17, SEKISUI silicon sealant Clear (model SSBCL-333) of SEKISUI FULLER Co., Ltd., which is a polysilicone resin, is used. The distance L11 between the end edge of the laminate 18 and the conductor 12 is 0. The conductor 12 is located at the end edge of the substrate 13 of the laminate 18. The length L10 of one side of the radio wave reflector 11 is 20.1 cm. The other structures are the same as those in Example 21.

(Example 24) The electric wave reflector 11 made as Example 24 is a radio wave reflector 11 having the same structure as the embodiment shown in Figure 7 as Example 23. The difference from Example 23 is that the sealing material 17 uses an acrylic resin. The acrylic resin is PMMA (polymethyl methacrylate). The other structures are the same as Example 23.

(Example 25) The radio wave reflector 11 manufactured as Example 25 is a radio wave reflector 11 having the same structure as the embodiment shown in Figure 7 as Example 23. The difference from Example 23 is that an epoxy resin is used as the sealing material 17. The epoxy resin contains jER828 (epoxy equivalent 190) of Mitsubishi Chemical Co., Ltd. as the epoxy main agent, and contains JERCURE YN100 (amine value 350 KOHmg/g, amine equivalent 80.1) of Mitsubishi Chemical Co., Ltd. as the curing agent. The curing time is 3 days and the curing temperature is 40 degrees. The other structures are the same as Example 23.

(Example 26) The difference between the radio wave reflector 11 manufactured as Example 26 and Example 21 is that the distance L11 between the edge 13a of the substrate 13 of the laminate 18 and the conductor 12 is set to 1 mm. The other structures are the same as those of Example 21.

(Comparative Example 21) The radio wave reflector 11 manufactured as Comparative Example 21 is different from Example 21 in the following aspects. The distance L11 between the edge of the substrate 13 of the laminate 18 and the conductor 12 is 0, and the conductor 12 exists along the edge of the substrate 13 of the laminate 18. The other structures are the same as Example 21.

(Measurement method and calculation method)  (Measurement of yellowness index and calculation of difference in yellowness index)  The difference in yellowness index is calculated by the following method. First, the yellowness index (YI0) of Examples 21 to 26 and Comparison Example 1 (hereinafter also referred to as "samples") as the measurement objects is measured. Then, a heat and moisture resistance test is performed on the samples, and the yellowness index (YI) of the samples after the heat and moisture resistance test is measured. Then, the difference in yellowness index is calculated by subtracting the yellowness index (YI0) before the heat and moisture resistance test from the yellowness index (YI) after the heat and moisture resistance test. That is, the difference in yellowness index = YI - YI0. The measurement of the yellowness index is performed by a method in accordance with JIS K7373. The heat and humidity resistance test is conducted as follows: after placing the radio wave reflector 11 in a constant temperature and humidity chamber adjusted to a temperature of 60°C and a humidity of 95%RH (relative humidity of 95%) for 500 hours, the radio wave reflector 11 is taken out of the constant temperature and humidity chamber and left at room temperature for 4 hours.

(Measurement of surface resistivity)  The surface resistivity is measured by the four-terminal method in accordance with JIS K6911 with the measuring terminals in contact with the surface of the conductive layer 16 in a state where the conductive layer 16 is exposed and formed during the manufacture of the sample before the heat and moisture resistance test. In addition, for the sample after the heat and moisture resistance test, since the conductive layer 16 is not exposed, a non-contact resistance meter (manufactured by Napson Co., Ltd., trade name: EC-80P or its equivalent) is used to measure the surface resistivity.

(Calculation of the rate of change of surface resistivity during the heat and humidity test)  The rate of change r of surface resistivity during the heat and humidity test is calculated by the following method. First, the surface resistivity of the sample before the heat and humidity test is measured. Then, the heat and humidity test is performed on the sample, and the surface resistivity of the sample after the heat and humidity test is measured. Then, the rate of change of surface resistivity during the heat and humidity test is calculated according to the formula: rate of change r of surface resistivity during the heat and humidity test = (surface resistivity r1 before the heat and humidity test - surface resistivity r2 after the heat and humidity test) / surface resistivity r1 before the heat and humidity test × 100. The surface resistivity of the conductor 12 of the conductive layer 16 is used as the surface resistivity of the radio wave reflector 11.

The case where the change rate of surface resistivity is less than 10% is evaluated as "◎", the case where the change rate of surface resistivity is more than 10% and less than 20% is evaluated as "○", and the case where the change rate of surface resistivity is more than 20% is evaluated as "×". In the case where the change rate of surface resistivity is "◎" or "○", it means that the surface resistivity does not change significantly before and after the heat and moisture resistance test, and is practical in use.

(Measurement of reflection intensity) The intensity of the reflected wave of the sample and the frequency band where the reflection intensity becomes -30 dB or more are measured in accordance with the reflection quantity measurement method described in JISR1679:2007. The sample is placed on the sample stand in a flat state, and the transmitting antenna and the receiving antenna are arranged according to the incident angle θ1 and the reflection angle θ2 of the radio wave (θ1, θ2 = 45 degrees). The distance between the sample and the receiving antenna and the distance between the sample and the transmitting antenna are set to 1 m. Output radio waves with frequencies varying from 3 GHz to 300 GHz (3 GHz radio waves, 5 GHz radio waves, and above 30 GHz radio waves varying from 30 GHz to 300 GHz (i.e. 30, 60, 90, 120...300 GHz)) from the transmitting antenna, and measure the amount of reflection (reflection intensity) corresponding to the radio waves. Also, find the frequency band where the reflection amount becomes -30 dB or more.

First, place a reference metal plate (aluminum A1050 plate, 3 mm thick) on the sample stand, and use a pure network analyzer to measure the receiving level and record it. At this time, use the pure network analyzer to directly connect the coaxial cable of the receiving antenna and the transmitting antenna, and calibrate the signal level of each frequency to 0. Then, reassemble the device and perform the measurement. Remove the reference metal plate from the sample stand, place the sample on the sample stand, measure the receiving level and record it. Subtract the receiving level of the reference metal plate from the measured receiving level to calculate the reflection amount in the regular reflection direction of the measured object radio wave reflector 11. Repeat the same measurement for each sample. Furthermore, when the frequency of radio waves is below 10 GHz, a millimeter wave lens is appropriately used to illuminate the sample with a plane wave in consideration of the first Fresnel radius of the rectangular horn antenna.

(Difference in reflection intensity)  Regarding the radio wave reflector 11 before and after the heat and moisture resistance test, the reflection intensity of radio waves with a frequency changed from 3 GHz to 300 GHz (3 GHz radio waves, 5 GHz radio waves, and above 30 GHz are changed to 300 GHz at intervals of 30 GHz (i.e., 30, 60, 90, 120...300 GHz)) is determined. Then, the difference (absolute value) in radio wave reflection intensity before and after the heat and moisture resistance test is determined for each frequency. The maximum value of the difference is shown in Table 3. If the difference (absolute value) is less than 2, it means that the reflection intensity of the radio wave reflector 11 does not decrease, and it is practical in use.

(Test results) The test results are shown in Table 3. In Example 21 and Example 22, the conductor 12 is formed on the inner side of the end edge 13a of the substrate 13 of the laminate 18 at a distance of 10 mm and 5 mm respectively, and the difference in the yellowness index before and after the heat and moisture resistance test is relatively small, which is 0.4 and 0.6 respectively. In addition, the change rate of the surface resistivity is evaluated as "◎". Furthermore, in all frequency bands above 3 GHz and below 300 GHz, the reflection intensity of the radio wave reflector 11 before and after the heat and moisture resistance test of Example 21 is -20 dB. The difference in reflection intensity is zero, and the reflection intensity is not reduced at all. In this way, in Example 21 and Example 22, no deterioration was found before and after the heat and moisture resistance test.

In Example 26, the conductor 12 is formed 1 mm inside the edge of the laminate 18, and the difference in yellowness index is 3.2, which is greater than that in Example 21. However, the change rate of surface resistivity is evaluated as "○". At a frequency of 27.5 GHz in the frequency band between 3 GHz and 300 GHz, the reflection intensity of the radio wave reflector 11 before the heat and humidity resistance test is -20 dB, and the reflection intensity after the heat and humidity resistance test is -21 dB, and the difference in reflection intensity is 1. The reflection intensity is slightly reduced, but it is still practical in use.

In Examples 23 to 25, although the conductor 12 is formed on the edge 13a of the substrate 13 of the laminate 18, the conductor 12 is covered by the sealing material 17. In Examples 23 to 25, silicone resin, acrylic resin, and epoxy resin are used as the sealing material 17. The difference in yellowness index of Examples 23 to 25 is small, which is 0.1, and the change rate of surface resistivity is evaluated as "◎". Furthermore, in all frequency bands above 3 GHz and below 300 GHz, the reflection intensity of the radio wave reflector 11 of Example 21 before and after the heat and humidity resistance test is -20 dB. The difference in reflection intensity is zero, and the reflection intensity is not reduced at all.

In contrast, in Comparative Example 1, the conductor 12 is formed on the edge 13a of the substrate 13 of the laminate 18, and the sealing material 17 is not provided, so the conductor 12 is exposed to the outside. The difference in the yellow index is large, 4.0, and the surface resistivity change rate is evaluated as "×". At a frequency of 27.5 GHz in the frequency band above 3 GHz and below 300 GHz, the reflection intensity of the radio wave reflector 11 before the heat and humidity resistance test is -20 dB, and the reflection intensity after the heat and humidity resistance test is -25 dB, and the difference in reflection intensity is 5, which means that the reflection intensity is greatly reduced.

[table 3] Embodiment 21 Embodiment 22 Embodiment 23 Embodiment 24 Embodiment 25 Embodiment 26 Comparative Example 21 Distance between the edge of the laminate and the conductor (mm) 10 5 0 0 0 1 0 Whether there is sealing material without without have have have without without Types of sealing materials - - Polysilicone Acrylic Epoxy series - - Reviews Yellowness Index Difference 0.4 0.6 0.1 0.1 0.1 3.2 4.0 Change rate of surface resistivity during heat and humidity resistance test ◎ ◎ ◎ ◎ ◎ ○ × Difference in reflection intensity 0 0 0 0 0 1 5

<Variations> The above-mentioned implementation method is only one of the various implementation methods of the present invention. As long as the purpose of the present invention can be achieved, the implementation method can be variously modified according to the design, etc. The following lists the variations of the implementation method. The variations described below can be appropriately combined and applied.

(1) Variation 1 The conductive layer 16 may have a special material structure, for example. The special material structure is formed by periodically arranging sheet-shaped conductors 12 as dielectrics. The periodic arrangement structure has a negative dielectric constant and reflects radio waves belonging to a specific frequency band determined based on the periodic interval. The shape of each conductor 12 is not limited and may be the above-mentioned shape. For example, as shown in FIG. 9 , each conductor 12 may also be a square. The length L20 of one side and the interval L21 between adjacent conductors 12 may be set in such a way that the conductor 12 reflects radio waves with a frequency of more than 3 GHz and less than 300 GHz. In this case, the length L20 of one side of the conductor 12 can be greater than 0.7 mm and less than 800 mm, and the interval L21 can be greater than 1 μm and less than 1000 μm. The thickness L3 of the conductor 12 is preferably less than 350 nm (0.35 μm), more preferably less than 100 nm, and further preferably less than 50 nm. The number of conductors 12 is appropriately set according to the size (area) of the substrate 13. As an example, the conductor 12 can be formed on the substrate 13 in a total of 4, 2 in the longitudinal direction and 2 in the transverse direction, depending on the size of the substrate 13. In this case, the length L20 of one side of each conductor 12 is set to 77.460 mm, the interval L21 between adjacent conductors 12 is set to 100 μm, and the thickness L3 is set to less than 350 nm (0.35 μm). The conductive layer 16 is not limited to a special material structure, and can also be any one of metal nanowire laminated film, multi-layer graphene, and partially exfoliated graphite.

(2) Variation 2 As shown in FIG. 10 , the radio wave reflector 11 may be stacked in a plurality of layers in the vertical direction. For example, another conductive layer 16B is connected to the conductive layer 16A via the bonding layer 14A, and a protective layer 15 is connected to the conductive layer 16B via the bonding layer 14B. The conductive layer 16A has a substrate 13 and a conductor 12 in the same manner as in the embodiment. The conductive layer 16B has a substrate 13 and a conductor 12 in the same manner.

Furthermore, the number of the conductors 12 formed on the conductive layer 16 may be three or more. If the number of the conductors 12 is increased, the reflection intensity increases, but since the thickness of the radio wave reflector 11 increases, the flexibility decreases, and the visible light transmittance also decreases. Therefore, when the radio wave reflector 11 is provided at a location where flexibility or transparency is not required, the number of layers may be appropriately set according to the intended use, such as increasing the number of layers.

(3) Modification 3 The conductor 12 may be in a form as shown in FIG. 11 . The conductor 12 is formed into a pattern in which a first conductive portion 4 including a plurality of first surrounding portions 41 and a second conductive portion 5 including a plurality of second surrounding portions 51 overlap. The first surrounding portion 41 and the second surrounding portion 51 do not have a common portion when projected onto a projection plane parallel to the conductive layer.

In the first conductive portion 4, the first surrounding portion 41 surrounding the first region R1 where the conductive body 12 is not formed is repeatedly formed at a certain interval. Here, the first conductive portion 4 is formed in a lattice shape, but may also be formed in a pentagonal, hexagonal, circular, or the like.

In the second conductive portion 5, the second surrounding portion 51 surrounding the fourth region R4 as a region where the conductor 12 is not formed is repeatedly formed at a certain interval. The fourth region R4 is formed to span a plurality of adjacent first regions R1. The second conductive portion 5 may be located on the same plane as the first conductive portion 4, or on a different plane. That is, the second conductive portion 5 may be conductive relative to the first conductive portion 4, or may not be conductive. In addition, the adjacent second conductive portions 5 may be separated from each other or may be connected. Furthermore, the second conductive portion 5 is formed into a quadrilateral, or may be formed into a pentagon, a hexagon, etc. Furthermore, FIG. 11 and FIG. 12 described below show the configuration of the conductor 12 when viewed from above, and the protective layer 15 and the bonding layer 14 are not shown.

The conductive body 12 of the modification 3 can improve the radio wave diffusivity. The "radio wave diffusivity" mentioned here means that the difference between the regular reflection intensity and the radio wave intensity around the regular reflection falls within a certain range.

(4) Variation 4 The conductor 12 may be, for example, in the form shown in FIG. 12 . The difference between the form of FIG. 12 and the form of FIG. 11 lies in the shape of the second conductive portion 5 (second surrounding portion 51 ), and the second surrounding portion 51 is circular. The center point of the second surrounding portion 51 is arranged to overlap with the intersection of the first conductive portion 4 formed in a grid shape, and the diameter of the second surrounding portion 51 is equal to the grid spacing of the first conductive portion 4. That is, adjacent second surrounding portions 51 are connected to each other. Furthermore, adjacent second surrounding portions 51 may also be separated from each other. The other structures are the same as those of Variation 3, so the corresponding structures are marked with the same symbols and the description is omitted.

By having the circular second surrounding portion 51, the effect of the incident direction on the reflection intensity of the radio wave reflector 11 in a plan view can be reduced. In other words, in this case, regardless of the direction from which the radio wave is incident on the radio wave reflector 11 in a plan view, the change in the diffusivity corresponding to the incident direction can be reduced.

(5) Variation 5 The conductive layer 16 of the radio wave reflector 11 may not have the base material 13. In this case, all the conductors 12 of the conductive layer 16 are supported by the bonding layer 14 and the protective layer 15, and when viewed from above, all the conductors 12 of the conductive layer 16 are covered by the bonding layer 14 and the protective layer 15. Furthermore, when the protective layer 15 has adhesion, only the protective layer 15 may be provided. In other words, the protective layer 15 may also serve as the base material 13 to support the conductor 12.

The radio wave reflector 11 is arranged such that the conductor 12 faces the installation surface of the installation location, and the conductor 12 is directly in contact with the installation surface or is in contact with the installation surface via a bonding layer, etc. The conductor 12 is covered by the bonding layer 14 and the protective layer 15 and the installation surface in a plan view, and the conductor 12 is not exposed to the outside, thereby preventing deterioration.

(6) Others In the above-mentioned embodiments, the radio wave reflector 11 is formed into a sheet shape, but the present invention is not limited thereto, and may be in the shape of a plate, a block, a sphere, a box, etc. In addition, the installation object of the radio wave reflector 11 is not limited to building materials, and may also be electrical appliances, building structures, cars, trains, airplanes, etc.

In the above embodiment, the radio wave reflector 11 has the bonding layer 14 between the conductive layer 16 and the protective layer 15, but if the protective layer 15 has self-bonding force, the bonding layer 14 may be omitted. In addition, the protective layer 15 may be fixed to the conductive layer 16 by sealing the outer edge with a sealing material without relying on the bonding layer 14. Furthermore, the protective layer 15 does not necessarily need to be fixed to the conductive layer 16.

One embodiment of the present invention has been described above, but the present invention is not limited to the above-mentioned embodiment, and various changes can be made within the scope of the subject matter of the present invention. The dimensions, materials, shapes, relative configurations, etc. of the components recorded as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only strictly indicate such configurations, but also indicate a state in which displacement occurs relative to each other at a tolerance, or at an angle or distance to the extent that the same function can be obtained. For example, expressions such as "same", "equal" and "homogeneous" that indicate that things are in an equal state do not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference in the degree to which the same function can be obtained. For example, expressions such as quadrilateral or cylinder that indicate shapes do not only indicate shapes such as quadrilateral or cylinder in the strict sense of geometry, but also indicate shapes that include concave and convex parts or chamfered parts within the scope of being able to obtain the same effect. The expression "includes", "contains", "has", "includes" or "has" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

In this specification, sometimes, expressions accompanied by "approximately" are used, such as "approximately parallel" or "approximately orthogonal". For example, "approximately parallel" means substantially "parallel", not only the state of strict "parallelism", but also means including errors of several degrees. The same applies to other expressions accompanied by "approximately".

In addition, in this specification, expressions such as "end" and "end" are distinguished by the presence or absence of "part". For example, "end" means the end of an object, and "end" means a region with a certain range including the "end". Any point within a certain range including the end is considered an "end". The same applies to other expressions accompanied by "part".

11: Radio wave reflector 12: Conductor 12a: First region (region without conductor) 12b: Second region (region without conductor) 12c: Third region (region without conductor) 13: Substrate 14: Adhesive layer 15: Protective layer 16: Conductive layer 17: Sealing material 18: Laminated body

[Figure 1] is a schematic diagram for explaining the angle range of the reflected wave reflected by the radio wave reflector of the embodiment.   [Figure 2] is a schematic cross-sectional view of the radio wave reflector of the embodiment.   Figure 3 (A) of [Figure 3] is a schematic plan view of the entire radio wave reflector of the embodiment, and Figure 3 (B) is an enlarged view of the A part of (A).   [Figure 4] is an enlarged view of the C part of Figure 3 (A).   Figures 5 (A) to (E) of [Figure 5] are schematic plan views showing variations of the configuration pattern of the conductor.   Figure 6 (A) of [Figure 6] is an explanatory view showing an example of use of the radio wave reflector of the embodiment. Figure 6 (B) is a schematic plan view showing an example of indoor application of the building material. FIG. 7 (A) of [FIG. 7] is a schematic plan view of the entire radio wave reflector of another embodiment, and FIG. 7 (B) is a schematic cross-sectional view of a portion of the radio wave reflector of another embodiment.   [FIG. 8] is a schematic plan view of the entire radio wave reflector of another embodiment.   [FIG. 9] is a schematic cross-sectional view of the radio wave reflector of variation 1.   [FIG. 10] is a schematic cross-sectional view of the radio wave reflector of variation 2.   FIG. 11 (A) of [FIG. 11] is a schematic plan view of the radio wave reflector of variation 3. FIG. 11 (B) is an enlarged view of portion B of FIG. 11 (A).   FIG. 12 (A) of [FIG. 12] is a schematic plan view of the radio wave reflector of variation 4. FIG. 12 (B) is an enlarged view of portion B of FIG. 12 (A).

11: Radio wave reflector

12: Conductor

13: Base material

14: Next layer

15: Protective layer

16: Conductive layer

18: Layered body

L1: Thickness of radio wave reflector

L2: Thickness of substrate

L3: Thickness of the conductor

L4: Thickness of the next layer

L5: Thickness of protective layer

Claims (25)

A radio wave reflector, comprising: a conductive layer comprising a conductor for reflecting radio waves; and a protective layer for protecting the conductive layer; and when a pencil hardness test is performed on the radio wave reflector, the pencil hardness of the protective layer when a surface load of 500 g is applied is above F. The radio wave reflector of claim 1, wherein the thickness of the protective layer is greater than 38 μm. The radio wave reflector of claim 1, wherein, when the protective layer is subjected to a pencil hardness test, the pencil hardness of the protective layer when a surface load of 500 g is applied is F or higher. The radio wave reflector as claimed in claim 1 further comprises a bonding layer, wherein the bonding layer is disposed between the conductive layer and the protective layer and bonds the conductive layer to the protective layer, and the hydroxyl value of the bonding layer is greater than 5 mgKOH/g. The radio wave reflector as claimed in claim 1 further comprises a bonding layer, wherein the bonding layer is arranged between the conductive layer and the protective layer and bonds the conductive layer to the protective layer, and the acid value of the bonding layer is less than 50 mgKOH/g. The radio wave reflector of claim 1, wherein the moisture permeability of the protective layer at 40°C and 90% rh is less than 20 g/ ^m2 ·24 h. The radio wave reflector of claim 1, wherein the adhesion of the protective layer to the adhered layer decreases by less than 50% after a heat and moisture resistance test. The radio wave reflector of claim 1, wherein the total light transmittance of the radio wave reflector is greater than 70%. The radio wave reflector as claimed in claim 1 further comprises a bonding layer, wherein the bonding layer is arranged between the conductive layer and the protective layer and connects the conductive layer to the protective layer, and the bonding layer does not contain an ultraviolet radiation inhibitor. As for the radio wave reflector of claim 1, the above-mentioned conductive layer has an area without the above-mentioned conductor, and the above-mentioned conductor is formed in a manner of surrounding the above-mentioned area, the above-mentioned area includes a plurality of areas of the same shape, and the above-mentioned plurality of areas of the same shape are arranged at certain intervals. The radio wave reflector of claim 1, wherein the surface resistivity of the radio wave reflector after heat and moisture resistance test is less than 100 Ω/□. The radio wave reflector of claim 1, wherein the protective layer contains an ultraviolet ray inhibitor or has been subjected to an ultraviolet ray blocking treatment on its surface. The radio wave reflector of claim 1, wherein the haze of the radio wave reflector is less than 30%. The radio wave reflector of claim 1, wherein the total light transmittance of the radio wave reflector after a light resistance test is greater than 70%. The radio wave reflector of claim 1, wherein the yellowing degree Δb* of the radio wave reflector before and after the light resistance test is 15 or less. The radio wave reflector as claimed in claim 1 comprises a laminate having the protective layer and the conductive layer, and when viewed from above, all the conductive bodies are covered by the protective layer. As for the radio wave reflector of claim 16, the above-mentioned laminate further has a bonding layer for connecting the above-mentioned protective layer and the above-mentioned conductive layer, the above-mentioned conductive body is arranged on the inner side of the end edge of the above-mentioned protective layer when viewed from above, and the above-mentioned conductive body is covered by the above-mentioned bonding layer when viewed from the side. As in claim 17, the conductive layer further comprises a substrate supporting the conductive body, the conductive body is located between the substrate and the protective layer, and is arranged on the inner side of the edge of the substrate when viewed from above. As for the radio wave reflector of claim 16, the above-mentioned conductor is arranged on the inner side more than 5 mm away from the edge of the above-mentioned protective layer when viewed from above. The radio wave reflector of claim 16, wherein a sealing material is provided around the laminate at least at a position corresponding to the conductive layer so as to prevent the conductive body from being exposed. For the radio wave reflector as claimed in claim 16, the difference between the yellowness index after the heat and humidity resistance test and the yellowness index before the above-mentioned heat and humidity resistance test is less than 3, and the above-mentioned heat and humidity resistance test is the following test: after placing the above-mentioned radio wave reflector in a constant temperature and humidity tank adjusted to a temperature of 60°C and a humidity of 95%RH for 500 hours, the above-mentioned radio wave reflector is taken out from the above-mentioned tank and left at room temperature for 4 hours. The radio wave reflector as claimed in claim 1, wherein, when the incident wave with a frequency of 3 GHz to 300 GHz is normally reflected by the radio wave reflector after the heat and humidity resistance test and the radio wave reflector before the heat and humidity resistance test, there is at least one frequency of the incident wave for which the difference between the intensity of the reflected wave of the radio wave reflector after the heat and humidity resistance test and the intensity of the reflected wave of the radio wave reflector before the heat and humidity resistance test is within 3 dB. The heat and humidity resistance test is the following test: after placing the radio wave reflector in a constant temperature and humidity tank adjusted to a temperature of 60°C and a humidity of 95%RH for 500 hours, the radio wave reflector is taken out from the tank and left to stand at room temperature for 4 hours. A method for manufacturing a radio wave reflector of claim 20, comprising: a step of forming the above-mentioned laminate; and a step of providing a sealing material for preventing the above-mentioned conductor from being exposed; and in the above-mentioned radio wave reflector, the above-mentioned sealing material is located at a position around the above-mentioned laminate at least corresponding to the above-mentioned conductive layer. A construction method for a radio wave reflector of claim 20, comprising: a step of installing the above-mentioned laminate at a setting position; and a step of setting a sealing material for preventing the above-mentioned conductor from being exposed; and in the above-mentioned radio wave reflector, the above-mentioned sealing material is located at a position around the above-mentioned laminate at least corresponding to the above-mentioned conductive layer. A construction method for a radio wave reflector as claimed in claim 24, wherein, in the above-mentioned installation step, a plurality of the above-mentioned laminated bodies are installed at the installation position with spaced intervals, and in the above-mentioned step of installing the sealing material, the above-mentioned sealing material is installed in the space between the adjacent above-mentioned laminated bodies when the plurality of the above-mentioned laminated bodies are installed at the installation position with spaced intervals.

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