Radio wave reflector, method for manufacturing a radio wave reflector, and system for manufacturing a radio wave reflector

Abstract

The objective is to provide a radio wave reflector that allows for easy adjustment of the reflection angle. [Solution] The radio wave reflector 11 of the present invention comprises a reflective material 20 having a reflective surface 21 that reflects radio waves, and a transparent substrate 30 attached to the surface of the reflective material 20 opposite to the reflective surface 21. The transparent substrate 30 has a reflective material mounting surface 31 to which the reflective material 20 is attached, and an installation surface 32 on the object 110 to which the radio wave reflector 11 is installed. The reflective material mounting surface 31 is inclined with respect to the installation surface 32, and the inclination angle α of the reflective material mounting surface 31 with respect to the installation surface 32 is greater than 0 degrees and 45 degrees or less.

Description

Technical Field

[0001] The present invention relates to a radio wave reflector, a method for manufacturing a radio wave reflector, and a radio wave reflector manufacturing system.

Background Art

[0002] In mobile phones and wireless communications, radio waves in a frequency band of about 3 GHz or more and 300 GHz or less, called centimeter waves and millimeter waves, are used. Such radio waves with short wavelengths have strong straightness. If there are obstacles between the transmitting antenna and the receiving antenna, it is difficult for the radio waves to bend around, and it becomes difficult for the radio waves to reach the receiving antenna. Therefore, in order to make the radio waves reach the blind spots where the radio waves cannot reach, reflectors are provided on the surfaces of buildings such as the walls, floors, ceilings, and columns of buildings (hereinafter referred to as "walls, etc.").

[0003] As reflectors, there are those that reflect radio waves by specular reflection where the incident angle and the reflection angle of the radio waves are the same. Also, in Patent Document 1, a reflector designed such that the incident angle and the reflection angle of radio waves are different has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] These reflectors are so-called passive reflectors in which the reflection angle is determined relative to the incident angle of radio waves. In a passive reflector, the reflection angle of radio waves is determined by the pattern of reflection elements included in the reflector. Therefore, it is necessary to design the pattern of reflection elements according to the reflection angle, which results in a so-called one-angle-one-design, and a mold is required for each design.

[0006] To install a reflector on a wall or other surface, the angle of the wall and the desired direction of radio wave reflection must be determined in advance, and a reflector with an appropriate reflection angle corresponding to these angles and directions must be designed. However, the actual reflection angle of the reflector may deviate from the design value, or the direction of radio wave reflection may shift from the desired direction during installation at the site, resulting in an angular deviation in the direction of radio wave reflection by the reflector. Since the reflection angle of passive reflectors cannot be adjusted, the reflector will be installed with an angular deviation, resulting in the problem that it cannot reflect radio waves sufficiently. It is also conceivable to prepare reflectors with different reflection angles to accommodate angular deviations, but this requires designing molds and reflective element patterns for each reflection angle, which is time-consuming.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a radio wave reflector, a method for manufacturing a radio wave reflector, and a radio wave reflector manufacturing system that allow for easy adjustment of the direction of radio wave reflection. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention encompasses the subject matter described in the following sections.

[0009] Item 1: A radio wave reflector that reflects radio waves, A reflective material having a reflective surface that reflects radio waves, The reflective material comprises a transparent substrate attached to the surface of the reflective material opposite to the reflective surface, The transparent substrate has a reflective material mounting surface to which the reflective material is attached, and an mounting surface to which the radio wave reflector is installed on the object to be installed. A radio wave reflector in which the reflective material mounting surface is inclined with respect to the aforementioned mounting surface, and the inclination angle of the reflective material mounting surface with respect to the aforementioned mounting surface is greater than 0 degrees and 45 degrees or less.

[0010] Item 2: The radio wave reflector according to Item 2, wherein the transparent substrate is transparent glass or a transparent resin substrate.

[0011] Item 3: The radio wave reflector according to item 1 or 2, wherein the reflective material is transparent.

[0012] Item 4: The radio wave reflector according to any one of items 1 to 3, wherein the transparent substrate has a rectangular shape when viewed from a plane.

[0013] Item 5: A radio wave reflector according to any one of items 1 to 4, wherein, when the direction perpendicular to the installation surface is defined as the vertical direction, the shortest distance between the installation surface and the reflective material mounting surface in the vertical direction is 0.5 μm or more and 10 μm or less, and the longest distance between the installation surface and the reflective material mounting surface in the vertical direction is 0.5 μm or more and 2000 mm or less.

[0014] Item 6: The radio wave reflector according to any one of items 1 to 5, further comprising an adhesive layer between the reflective material and the transparent substrate for bonding the reflective material and the transparent substrate.

[0015] Item 7: A radio wave reflector according to any one of items 1 to 6, wherein the angle of reflection of the radio waves reflected by the reflecting material is different from the angle of incidence.

[0016] Item 8: The radio wave reflector according to any one of items 1 to 7, wherein the reflector includes a conductor and a resin layer.

[0017] Item 9: The radio wave reflector according to any one of items 1 to 8, further comprising an adhesive layer for installation on the installation surface of the transparent substrate for installation on the object to be installed.

[0018] Item 10: A method for manufacturing a radio wave reflector, A process for obtaining a reflective material having a reflective surface that reflects radio waves at a desired reflection angle, A step to obtain a plurality of transparent substrates having a reflective material mounting surface to which the reflective material is attached and an installation surface to an object on which the radio wave reflector is installed, wherein each transparent substrate has the reflective material mounting surface inclined with respect to the installation surface, the inclination angle of the reflective material mounting surface with respect to the installation surface is greater than 0 degrees and 45 degrees or less, and the inclination angles of the plurality of transparent substrates are different, A step of selecting a transparent substrate with an appropriate tilt angle from among the plurality of transparent substrates so that the reflector reflects radio waves in a desired radio wave reflection direction; A method for manufacturing a radio wave reflector, comprising: a step of attaching the reflector attachment surface of the selected transparent substrate to a surface opposite to the reflection surface of the reflector with an adhesive layer.

[0019] Item 11: A system for manufacturing a radio wave reflector, comprising: One or more reflectors having a reflection surface for reflecting radio waves; And a plurality of transparent substrates, Each transparent substrate has a reflector attachment surface to which the reflector can be attached and an installation surface on an object to which the radio wave reflector is to be installed. In each transparent substrate, the reflector attachment surface is inclined with respect to the installation surface, the inclination angle of the reflector attachment surface with respect to the installation surface is greater than 0 degrees and 45 degrees or less, and the inclination angles of the plurality of transparent substrates are different. A radio wave reflector manufacturing system.

Advantages of the Invention

[0020] According to the present invention, it becomes easy to adjust the reflection angle of the radio wave reflector.

Brief Description of the Drawings

[0021] [Figure 1] It is a front view showing the overall schematic configuration of a radio wave reflector according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along the line A-A of FIG. 1. [Figure 3] It is an explanatory diagram of the incident angle and reflection angle of radio waves incident on and reflected from the radio wave reflector. [Figure 4] It is a diagram for explaining a radio wave reflector manufacturing system including a reflector and a plurality of transparent substrates.

Embodiments for Carrying Out the Invention

[0023] In this specification, the incident angle α1 is the angle between the direction of incidence when the incident wave is incident on the radio wave reflector 11 (for example, shown by arrow A1 in Figure 3) and the direction in which the normal to the reflective surface 21 of the radio wave reflector 11 extends (for example, shown by arrow A2 in Figure 3). The reflection angle α2 is the angle between the direction of reflection of the reflected wave (for example, shown by arrow A3 in Figure 3) and the normal to the reflective surface 21. The normal is a straight line perpendicular to the tangent (or tangent plane) at the point of reflection.

[0024] The incident wave is reflected as a reflected wave by the radio wave reflector 11 at a reflection angle α2. The reflective material 20 (described later) of the radio wave reflector 11 may reflect the radio wave at a reflection angle α2 that is the same angle as the incident angle α1, or it may reflect the radio wave at a reflection angle α2 that is different from the incident angle α1. Reflection of radio waves at a reflection angle α2 that is the same angle as the incident angle α1 is also called "specular reflection," and reflection at a reflection angle α2 that is a desired angle different from the incident angle α1 is also called "biased reflection."

[0025] In the example in Figure 3, the incident angle α1 of the incident wave is 60 degrees. The reflected wave may be reflected at the same reflection angle α2 as the incident angle α1, i.e., in Figure 3, in the direction of arrow A3 where the reflection angle α2 is 60 degrees. Alternatively, the reflected wave may be reflected at a desired reflection angle α2 different from the incident angle α1, for example, in Figure 3, in the direction of arrow A2 where the desired reflection angle α2 is 0 degrees.

[0026] The shape of the radio wave reflector 11 in plan view is not limited, but it is preferably a square, for example, with a side length of 20 cm or more and 400 cm or less. Radio waves with frequencies of 3 GHz or more and 300 GHz or less are attenuated with distance, but in order to reflect with sufficient intensity at all points within a practical distance from the radio wave source 100, it is preferable that the side length be 20 cm or more. There is no particular upper limit to the side length, but from a manufacturing standpoint, 400 cm or less is preferable. The overall shape of the radio wave reflector 11 is not limited to a square, but may be a rectangle, or a polygon such as a triangle, pentagon, or hexagon, in which case the length of the shortest side is set to 20 cm or more and 400 cm or less. Alternatively, the shortest distance between a vertex and the opposite side, or the shortest distance between a side and the opposite side, may be set to 20 cm or more and 400 cm or less. Furthermore, if the overall shape of the radio wave reflector 11 is circular, the diameter is set to 20 cm or more and 400 cm or less. If the overall shape of the radio wave reflector 11 is elliptical, the minor axis is set to be between 20 cm and 400 cm. If the overall shape of the radio wave reflector 11 is sector-shaped, the length of the shorter arc or radius is set to be between 20 cm and 400 cm. Furthermore, the overall shape of the radio wave reflector 11 may be a three-dimensional shape such as cylindrical or conical. The shape and size of the radio wave reflector 11 are appropriately selected according to the manner in which the radio wave reflector 11 is used.

[0027] (Structure of the radio wave reflector 11) As shown in Figures 1 and 2, the radio wave reflector 11 comprises a reflective material 20 having a reflective surface 21 that reflects radio waves, and a transparent substrate 30 attached to the surface of the reflective material 20 opposite to the reflective surface 21. Furthermore, it comprises an adhesive layer 40 for bonding the reflective material 20 and the transparent substrate 30, and an installation adhesive layer 41 for installing the transparent substrate 30 onto the object 110. Note that in this specification, the drawings are used to illustrate the radio wave reflector 11 and do not represent actual dimensions.

[0028] (Reflective material 20) The reflective material 20 is plate-shaped, with one side being a reflective surface 21 that reflects radio waves, and the side opposite the reflective surface 21 being a substrate mounting surface 22 to which the transparent substrate 30 is attached. The reflective material 20 is formed in a pattern in which a conductor (not shown) is placed on one surface of a resin layer (not shown), and since radio waves are reflected by the conductor, the side of the resin layer on which the conductor is provided becomes the reflective surface 21. The reflective material 20 may also have a protective layer that covers the conductor to protect it. If a protective layer is provided, the surface of the protective layer on the side of the resin layer of the reflective material 20 on which the conductor is provided may be referred to as the reflective surface 21.

[0029] The reflective material 20 is transparent. In the following description, "transparent" means that the other side is visible when viewed from one side, and includes translucency. Also, "transparent" includes being colored as a whole. The reflective material 20 preferably has a total light transmittance of 65% or more under a D65 standard light source, more preferably 80% or more, and even more preferably 95% or more.

[0030] It is preferable that the thickness L1 of the reflective material 20 is set to 1 mm or less. The thickness L1 of the reflective material 20 is set to a thickness that allows the reflective material 20 to be flexible and does not concentrate force on the conductor contained in the reflective material 20 when an external force is applied and the reflective material 20 is bent.

[0031] (Transparent base material 30) The transparent substrate 30 is transparent and is made of a substrate made of transparent glass or transparent synthetic resin. The transparent substrate 30 has a reflective material mounting surface 31 to which the reflective material 20 is attached and an installation surface 32 to which the radio wave reflector 11 is installed on an object 110 such as a wall. As shown in Figure 1, the transparent substrate 30 has a square shape in plan view and is designed to be slightly larger than the reflective material 20, but it may be the same size and shape as the reflective material 20. If the transparent substrate 30 is a substrate made of synthetic resin, the transparent substrate 30 may be flexible.

[0032] The transparent substrate 30 has a reflective material mounting surface 31 that is inclined with respect to the installation surface 32, and the inclination angle α of the reflective material mounting surface 31 with respect to the installation surface 32 is greater than 0 degrees and 45 degrees or less. The inclination angle α is the angle of the reflective material mounting surface 31 with respect to the installation surface 32 in a cross-section obtained by cutting vertically along a line connecting a point on a plane where the distance between the installation surface 32 and the reflective material mounting surface 31 is shortest in the vertical direction, and a point on a plane where the distance between the installation surface 32 and the reflective material mounting surface 31 is longest in the vertical direction, assuming that the direction perpendicular to the installation surface 32 is the vertical direction.

[0033] In this embodiment, in the left-right direction in Figure 1, one side of the mounting surface 32 and one side of the reflective material mounting surface 31 are parallel, and the other side of the mounting surface 32 and the other side of the reflective material mounting surface 31 are parallel. Therefore, as shown in Figure 2, the shortest distance L2 is between one side of the mounting surface 32 and one side of the reflective material mounting surface 31, and the longest distance L3 is between the other side of the mounting surface 32 and the other side of the reflective material mounting surface 31.

[0034] In Figure 1, the cross-section obtained by cutting the transparent substrate 30 vertically along a line connecting an arbitrary point on the left edge and an arbitrary point on the right edge (for example, the cross-section shown in Figure 2, along line AA in Figure 1) is trapezoidal, and the angle of the reflective material mounting surface 31 with respect to the installation surface 32 is the inclination angle α.

[0035] The shortest distance L2 between the mounting surface 32 and the reflective material mounting surface 31 in the vertical direction is designed to be between 0.5 μm and 10 μm, and the longest distance L3 between the mounting surface 32 and the reflective material mounting surface 31 in the vertical direction is designed to be between 0.5 μm and 2000 mm. The length of the transparent substrate 30 in the left-right direction is determined so that the inclination angle α is greater than 0 degrees and 45 degrees or less.

[0036] The planar shape of the transparent substrate 30 is not limited to a square, but can be any shape corresponding to the planar shape of the radio wave reflector 11 described above. Furthermore, the cross-sectional shape of the transparent substrate 30 is not limited to a trapezoid, but can be any shape, and the shortest distance L2 between the mounting surface 32 and the reflector mounting surface 31 may be zero, i.e., the reflector mounting surface 31 may be a right triangle with a hypotenuse.

[0037] (adhesive layer 40) The adhesive layer 40 is provided between the substrate mounting surface 22 of the reflective material 20 and the reflective material mounting surface 31 of the transparent substrate 30, and adheres the reflective material 20 and the transparent substrate 30. The adhesive layer 40 is made of an adhesive. The adhesive layer 40 is transparent and has a size corresponding to the reflective material 20 in a plan view. Examples of adhesives include, but are not limited to, synthetic resins such as acrylic resin, silicone resin, and polyvinyl alcohol resin, or rubber adhesive sheets. In this embodiment, the thickness of the adhesive layer 40 is set to 150 μm, but is not limited to this.

[0038] (Adhesive layer for installation 41) The adhesive layer 41 for installation is provided between the installation surface 32 of the transparent substrate 30 and the object to be installed 110, which is made of a wall or the like, and is used to attach the transparent substrate 30 to the object to be installed 110. The adhesive layer 41 for installation is transparent and has a size corresponding to the transparent substrate 30 in a plan view. Examples of adhesives include, but are not limited to, synthetic resins such as acrylic resin, silicone resin, and polyvinyl alcohol resin, or rubber adhesive sheets. In this embodiment, the thickness of the adhesive layer 41 is set to 150 μm, but is not limited to this.

[0039] (Radio wave reflector fabrication system 12) The radio wave reflector fabrication system 12 comprises one or more reflective materials 20 having a predetermined reflection angle and a plurality of transparent substrates 30 with different inclination angles α. The number of reflective materials 20 is less than the number of transparent substrates 30, preferably between 1 and 3, and more preferably 1 or 2. The example of the radio wave reflector fabrication system 12 shown in Figure 4 comprises two reflective materials 20A and 20B and nine transparent substrates 30A to 30I. For example, reflective materials 20A and 20B are designed to have reflection angles of 10 degrees and 80 degrees, respectively. In addition, the inclination angle α of each of the nine transparent substrates 30 is set to a value in 5-degree increments between 5 degrees and 45 degrees.

[0040] (Method for fabricating a radio wave reflector 11 using a radio wave reflector fabrication system 12) A method for manufacturing the radio wave reflector 11 will be described. The worker has in advance the direction the wall on which the radio wave reflector 11 will be installed will face and the direction in which the radio wave reflector 11 should reflect radio waves (the desired direction of radio wave reflection). The worker designs and manufactures a reflective material 20 so as to have a desired reflection angle corresponding to the desired direction of radio wave reflection, and obtains the reflective material 20. Alternatively, as shown in Figure 4, multiple reflective materials 20 having predetermined reflection angles may be designed and manufactured. Furthermore, the worker prepares multiple transparent substrates 30 with different inclination angles α. For example, nine transparent substrates 30A to 30I may be prepared, and the inclination angle α of each transparent substrate 30A to 30I may be set to a value between 5 degrees and 45 degrees in increments of 5 degrees.

[0041] At the installation site of the radio wave reflector 11, a transparent substrate 30 with an inclination angle α of 0 degrees is temporarily fixed to the reflector 20, and the transparent substrate 30 is temporarily installed on the installation target object 110 such as a wall. If there are multiple reflectors 20, a reflector 20 having a reflection angle close to the desired direction of radio wave reflection is selected.

[0042] If the reflective material 20 can reflect radio waves in the desired direction, the transparent substrate 30 is attached to the reflective material 20 with an adhesive layer 40 to create a radio wave reflector 11. Then, an adhesive layer 41 for installation is applied to the installation surface 32 of the transparent substrate 30, and the radio wave reflector 11 is attached to the object to be installed 110.

[0043] If the reflective material 20 reflects radio waves in a direction deviated from the desired reflection direction, the operator selects a transparent substrate 30 with an appropriate inclination angle α from among the multiple transparent substrates 30 of the radio wave reflector manufacturing system 12 so that the reflective material 20 can reflect radio waves in the desired reflection direction. The selected transparent substrate 30 is attached to the reflective material mounting surface 31 and the substrate mounting surface 22 of the reflective material 20 with an adhesive layer 40 to manufacture a radio wave reflector 11 as shown in Figures 1 and 2. Then, an adhesive layer 41 for installation is applied to the installation surface 32 of the transparent substrate 30 of the radio wave reflector 11 manufactured by the above method, and the radio wave reflector 11 is attached to the object to be installed 110.

[0044] In this way, the reflective material 20 is designed to a predetermined reflection angle, the inclination angle of the transparent substrate 30 is set to be greater than 0 degrees and 45 degrees or less, and the transparent substrate is selected so that the reflective material 20 reflects radio waves in the desired reflection direction. As a result, even if the reflection angle of radio waves of the radio wave reflector 11 deviates from the desired direction, the reflection direction of radio waves can be easily adjusted without changing the design of the conductor of the radio wave reflector 11.

[0045] Incidentally, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Expressions indicating that things such as "in a certain direction", "along a certain direction", "the same", "identical", "equal", and "homogeneous" are in an equal state represent not only a strictly equal state, but also a state in which there are tolerances or differences that allow the same function to be obtained. Expressions representing triangular, quadrangular, or circular shapes represent not only geometrically precise shapes, but also shapes including concavo-convex portions, chamfered portions, etc. within a range where the same effect can be obtained. The expressions "comprising", "having", "including", or "possessing" one component are not exclusive expressions excluding the existence of other components. "Parallel" and "orthogonal" mean substantially "parallel" and "orthogonal", and include not only a strictly "parallel" and "orthogonal" state, but also a state including errors of about several degrees. Also, in some cases, an expression such as "part" like "end part" may be used. For example, "end part" means a part having a certain range including the "end". The same applies to other expressions with "part".

Explanation of Reference Numerals

[0046] 11 Radio wave reflector 12 Radio wave reflector production system 20 Reflective material 21 Reflective surface 22 Substrate mounting surface 30 Transparent substrate 31 Reflective material mounting surface 32 Installation surface 40 Adhesive layer 41 Adhesive layer for installation L1 Thickness of reflective material L2, L3 Thickness of transparent substrate

Claims

1. A radio wave reflector that reflects radio waves, A reflective material having a reflective surface that reflects radio waves, The reflective material comprises a transparent substrate attached to the surface of the reflective material opposite to the reflective surface, The transparent substrate has a reflective material mounting surface to which the reflective material is attached, and an mounting surface to which the radio wave reflector is installed on the object to be installed. A radio wave reflector in which the reflective material mounting surface is inclined with respect to the aforementioned installation surface, and the inclination angle of the reflective material mounting surface with respect to the aforementioned installation surface is greater than 0 degrees and 45 degrees or less.

2. The radio wave reflector according to claim 1, wherein the transparent substrate is transparent glass or a transparent resin substrate.

3. The radio wave reflector according to claim 2, wherein the reflective material is transparent.

4. The radio wave reflector according to claim 1, wherein the transparent substrate has a rectangular shape when viewed from a planar perspective.

5. The radio wave reflector according to claim 1, wherein, when the direction perpendicular to the installation surface is defined as the vertical direction, the shortest distance between the installation surface and the reflective material mounting surface in the vertical direction is 0.5 μm or more and 10 μm or less, and the longest distance between the installation surface and the reflective material mounting surface in the vertical direction is 0.5 μm or more and 2000 mm or less.

6. The radio wave reflector according to claim 1, further comprising an adhesive layer between the reflective material and the transparent substrate for bonding the reflective material and the transparent substrate.

7. The radio wave reflector according to claim 1, wherein the angle of reflection of the radio waves reflected by the reflective material is different from the angle of incidence.

8. The radio wave reflector according to claim 1, wherein the reflective material includes a conductor and a resin layer.

9. The radio wave reflector according to claim 1, further comprising an adhesive layer for installation on the installation surface of the transparent substrate for installation on the object to be installed.

10. A method for manufacturing a radio wave reflector, A process for obtaining a reflective material having a reflective surface that reflects radio waves at a desired reflection angle, A step to obtain a plurality of transparent substrates having a reflective material mounting surface to which the reflective material is attached and an installation surface to an object on which the radio wave reflector is installed, wherein each transparent substrate has the reflective material mounting surface inclined with respect to the installation surface, the inclination angle of the reflective material mounting surface with respect to the installation surface is greater than 0 degrees and 45 degrees or less, and the inclination angles of the plurality of transparent substrates are different, The process of selecting a transparent substrate with an appropriate inclination angle from among a plurality of transparent substrates such that the reflective material reflects radio waves in the desired direction of reflection of radio waves, A method for manufacturing a radio wave reflector, comprising the step of attaching the reflective material mounting surface of the selected transparent substrate to the surface of the reflective material opposite to the reflective surface by means of an adhesive layer.

11. A system for fabricating radio wave reflectors, One or more reflective materials having a reflective surface that reflects radio waves, Equipped with multiple transparent substrates, Each transparent substrate has a reflective material mounting surface to which the reflective material can be attached, and an mounting surface to the object on which the radio wave reflector is installed. A radio wave reflector manufacturing system in which each transparent substrate has a reflective material mounting surface that is inclined with respect to the installation surface, the inclination angle of the reflective material mounting surface with respect to the installation surface is greater than 0 degrees and 45 degrees or less, and the inclination angles of the multiple transparent substrates are different.

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