Antenna unit and method for manufacturing antenna unit

Abstract

To provide an antenna unit capable of transmitting and receiving electromagnetic waves through a glass plate.SOLUTION: An antenna unit according to the present invention is installed on the indoor side of a glass plate and suspended from the ceiling, and includes an antenna and a space between the glass plate and the antenna through which air can flow, and transmits and receives electromagnetic waves from the indoor side through the glass plate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antenna unit and a method for manufacturing the antenna unit.

Background Art

[0002] A variety of communication systems using wireless technologies, such as mobile phones, Internet communication, radio broadcasting, and GPS (Global Positioning System), have been developed. To support these communication systems, an antenna capable of transmitting and receiving electromagnetic waves used in each communication system is required.

[0003] As an antenna unit installed and used on the outer wall surface of a building, for example, an antenna unit using a radio wave transmission body having three layers with different relative dielectric constants, each layer being set to a predetermined thickness and having good radio wave transmission performance, has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The radio wave transmission body described in Patent Document 1 uses a surface finishing material such as glass for the outermost first layer, uses a second layer such as an air layer inside the outermost layer, and uses a third layer such as a porous body or an acrylic resin inside that. And the relative dielectric constant of the radio wave transmission body is smaller in the order of the first layer, the third layer, and the second layer.

[0006] One aspect of the present invention aims to provide an antenna unit capable of transmitting and receiving electromagnetic waves through a glass plate.

Means for Solving the Problems

[0007] An antenna unit according to one aspect of the present invention is an antenna unit installed on the indoor side of a glass plate and suspended from the ceiling, and includes an antenna and a space in which air can flow between the glass plate and the antenna, and transmits and receives electromagnetic waves from the indoor side through the glass plate.

[0008] The antenna unit according to one aspect of the present invention preferably has a fixing portion for fixing the antenna to the ceiling so that a space in which air can flow is formed between the glass plate and the antenna.

Effects of the Invention

[0009] The antenna unit according to one aspect of the present invention can transmit and receive electromagnetic waves through a glass plate.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail. For ease of understanding, the scales of the respective members in the drawings may be different from the actual ones. In this specification, a three-dimensional orthogonal coordinate system in three axial directions (X-axis direction, Y-axis direction, Z-axis direction) is used. The width direction of the glass plate is defined as the X direction, the thickness direction as the Y direction, and the height direction as the Z direction. The direction from the bottom to the top of the glass plate is defined as the +Z axis direction, and the opposite direction as the -Z axis direction. In the following description, the +Z axis direction may be referred to as "up" and the -Z axis direction as "down".

[0012] <Antenna Unit for Glass> An antenna unit for glass according to an embodiment (hereinafter, also simply referred to as an antenna unit) will be described. Note that "for glass" in the "antenna unit for glass" indicates that it is used for the purpose of transmitting and receiving electromagnetic waves through glass.

[0013] FIG. 1 is a perspective view showing a state where the antenna unit is applied to the glass plate, FIG. 2 is a perspective view of the antenna unit, and FIG. 3 is a perspective view of the antenna unit shown in FIG. 1 as viewed from the fixing portion side.

[0014] As shown in FIGS. 1 to 3, the antenna unit 10 includes an antenna 11, a flat substrate (antenna mounting substrate) 12 on which the antenna 11 is provided, and a fixing portion 13A attached to the antenna mounting substrate 12. The antenna unit 10 is attached to the glass plate 20 by the fixing portion 13A so that a space S is formed between the antenna mounting substrate 12 and the glass plate 20. Note that when the glass plate 20 is a window glass, the outer edge of the glass plate 20 is held in a state of being sandwiched by the window frame 21. In FIG. 1, the antenna unit 10 is attached to the main surface on the indoor side of the glass plate 20. Then, sunlight or the like is irradiated on the main surface on the side opposite to the indoor side of the glass plate 20.

[0015] In this embodiment, the antenna unit 10 is fixed to the glass plate 20 (window glass) by the fixing portion 13A in FIG. 1, but is not limited thereto. For example, the antenna unit 10 can be suspended from the ceiling or fixed to a protrusion (for example, the window frame 21 or the window sash) existing around the glass plate 20 (window glass).

[0016] The antenna 11 is provided on the first main surface 121 of the antenna mounting substrate 12. The antenna 11 may be formed by printing a metal material so as to at least partially overlap a ceramic layer 14 provided on the first main surface 121 of the antenna mounting substrate 12. Thereby, the antenna 11 is provided across the portion where the ceramic layer 14 is formed and the other portion on the first main surface 121 of the antenna mounting substrate 12.

[0017] As the metal material for forming the antenna 11, a conductive material such as gold, silver, copper, or platinum can be used. Also, for the antenna 11, for example, a patch antenna, a dipole antenna, or the like can be used.

[0018] As another material for forming the antenna 11, fluorine-doped tin oxide (FTO), indium tin oxide (ITO), or the like can be mentioned.

[0019] The ceramic layer 14 can be formed on the first main surface 121 of the antenna mounting substrate 12 by printing or the like. By providing the ceramic layer 14, wiring (not shown) attached to the antenna 11 can be covered, and the design is good. In this embodiment, the ceramic layer 14 may not be provided on the first main surface 121, or may be provided on the second main surface 122 of the antenna mounting substrate 12. It is preferable to provide the ceramic layer 14 on the first main surface 121 of the antenna mounting substrate 12 because the antenna 11 and the ceramic layer 14 can be provided on the antenna mounting substrate 12 by printing in the same process.

[0020] The material of the ceramic layer is glass frit or the like, and its thickness is preferably 1 to 20 μm.

[0021] In this embodiment, the antenna 11 is provided on the first main surface 121 of the antenna mounting substrate 12, but it may be provided inside the antenna mounting substrate 12. In this case, the antenna 11 can be provided inside the antenna mounting substrate 12 in a coil shape, for example.

[0022] When the antenna mounting substrate 12 is a laminated glass including a pair of glass plates and a resin layer provided between the pair of glass plates, the antenna 11 may be provided between the glass plate and the resin layer constituting the laminated glass.

[0023] Also, the antenna 11 may be formed in a flat plate shape. In this case, the antenna mounting substrate 12 may not be used, and the flat plate-shaped antenna may be directly attached to the fixing portion 13A.

[0024] In addition to being provided on the substrate 12 for antenna installation, the antenna 11 may be provided inside the storage container. In this case, for example, a flat antenna can be provided inside the storage container. The shape of the storage container is not particularly limited and may be rectangular.

[0025] The antenna 11 preferably has light transmissivity. If the antenna 11 has light transmissivity, it has good design and can reduce the average solar radiation absorption rate. The visible light transmittance of the antenna 11 is preferably 40% or more, and more preferably 60% or more, which is preferable in terms of maintaining the function as window glass in terms of transparency. The visible light transmittance can be determined according to JIS R 3106 (1998).

[0026] The antenna 11 is preferably formed in a mesh shape in order to have light transmissivity. Note that the mesh refers to a state in which mesh-like through holes are formed in the plane of the antenna 11.

[0027] When the antenna 11 is formed in a mesh shape, the mesh openings may be square or diamond-shaped. The line width of the mesh is preferably 5 to 30 μm, and more preferably 6 to 15 μm. The line interval of the mesh is preferably 50 to 500 μm, and more preferably 100 to 300 μm.

[0028] The aperture ratio of the antenna 11 is preferably 80% or more, and more preferably 90% or more. The aperture ratio of the antenna 11 is the ratio of the area of the openings per area including the openings of the electromagnetic shielding layer 16. The larger the aperture ratio of the antenna 11, the higher the visible light transmittance of the antenna 11 can be.

[0029] The thickness of the antenna 11 is preferably 400 nm or less, and more preferably 300 nm or less. The lower limit of the thickness of the antenna 11 is not particularly limited, but it may be 2 nm or more, 10 nm or more, or 30 nm or more.

[0030] When the antenna 11 is formed in a mesh shape, the thickness of the antenna 11 may be 2 to 40 μm. By forming the antenna 11 in a mesh shape, even if the antenna 11 is thick, the visible light transmittance can be increased.

[0031] The substrate 12 for installing the antenna is provided parallel to the glass plate 20. The substrate 12 for installing the antenna is formed in a rectangle in plan view and has a first main surface 121 and a second main surface 122. The first main surface 121 is provided so as to face the main surface of the glass plate 20 to be attached, and the second main surface 122 is provided in a direction opposite to the main surface side of the glass plate 20.

[0032] In addition, in the present embodiment, the substrate 12 for installing the antenna may be provided at a predetermined angle with respect to the glass plate 20 (window glass). The antenna unit 10 may set a tilt angle in a direction that forms an angle with respect to the normal direction (the positive direction of the Y axis) of the surface formed by the antenna unit 10 and radiate electromagnetic waves. For example, when the antenna unit 10 is installed above the ground surface such as a glass window of a building and radiates electromagnetic waves toward the ground surface to form an area on the ground surface. The angle between the substrate 12 for installing the antenna and the glass plate 20 (window glass) may be 0 degrees or more, may be 5 degrees or more, and may be 10 degrees or more in terms of enabling good transmission direction of radio waves. Also, in order to transmit radio waves to the outside, the angle between the substrate 12 for installing the antenna and the glass plate 20 (window glass) may be 50 degrees or less, may be 30 degrees or less, and may be 20 degrees or less.

[0033] The material for forming the substrate 12 for installing the antenna is designed according to the antenna performance such as the power and directivity required for the antenna 11. For example, glass, resin, or metal can be used. The substrate 12 for installing the antenna may be formed of a resin or the like to have light transmissibility. By forming the substrate 12 for installing the antenna with a light-transmissive material, the glass plate 20 can be seen through the substrate 12 for installing the antenna, so that it is possible to reduce blocking the view visible from the glass plate 20.

[0034] When glass is used as the substrate 12 for antenna installation, examples of the glass material include soda-lime-silica glass, borosilicate glass, aluminosilicate glass, or alkali-free glass.

[0035] The glass plate used as the substrate 12 for antenna installation can be manufactured using known manufacturing methods such as the float method, fusion method, redraw method, press molding method, or drawing method. From the viewpoints of productivity and cost, it is preferable to use the float method as the manufacturing method of the glass plate.

[0036] The glass plate is formed in a rectangular shape in plan view. Examples of the cutting method of the glass plate include a method of irradiating the surface of the glass plate with a laser beam and moving the irradiation region of the laser beam on the surface of the glass plate for cutting, or a method of mechanically cutting with a cutter wheel or the like.

[0037] In the present embodiment, the rectangle includes not only a rectangle and a square but also a shape in which a roundness is formed at the corners of the rectangle and the square. The shape of the glass plate in plan view is not limited to a rectangle, and may be circular or the like. Further, the glass plate is not limited to a single plate, and may be laminated glass or multi-layer glass.

[0038] When resin is used as the substrate 12 for antenna installation, the resin is preferably a transparent resin, and examples thereof include liquid crystal polymer (LCP), polyimide (PI), polyphenylene ether (PPE), polycarbonate, acrylic resin, or fluororesin. Fluororesin is preferable from the viewpoint of low dielectric constant.

[0039] Examples of the fluororesin include ethylene-tetrafluoroethylene copolymers (hereinafter also referred to as "ETFE"), hexafluoropropylene-tetrafluoroethylene copolymers (hereinafter also referred to as "FEP"), tetrafluoroethylene-propylene copolymers, tetrafluoroethylene-hexafluoropropylene-propylene copolymers, perfluoro(alkyl vinyl ether)-tetrafluoroethylene copolymers (hereinafter also referred to as "PFA"), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymers (hereinafter also referred to as "THV"), polyvinylidene fluoride (hereinafter also referred to as "PVDF"), vinylidene fluoride-hexafluoropropylene copolymers, polyvinyl fluoride, chlorotrifluoroethylene polymers, ethylene-chlorotrifluoroethylene copolymers (hereinafter also referred to as "ECTFE"), or polytetrafluoroethylene. Any one of these may be used alone, or two or more of them may be used in combination.

[0040] As the fluororesin, at least one selected from the group consisting of ETFE, FEP, PFA, PVDF, ECTFE, and THV is preferable, and ETFE is particularly preferable in terms of excellent transparency, processability, and weather resistance.

[0041] Further, Afflex (registered trademark) may be used as the fluororesin.

[0042] The thickness of the substrate 12 for installing the antenna is preferably 25 μm to 10 mm. The thickness of the substrate 12 for installing the antenna can be arbitrarily designed according to the location where the antenna 11 is arranged.

[0043] When the substrate 12 for installing the antenna is a resin, it is preferable to use a resin formed into a film or sheet shape. The thickness of the film or sheet is preferably 25 to 1000 μm, more preferably 100 to 800 μm, and particularly preferably 100 to 500 μm in terms of excellent antenna holding strength.

[0044] When the substrate 12 for antenna installation is made of glass, the thickness of the substrate 12 for antenna installation is preferably 1.0 to 10 mm in terms of the strength of antenna holding.

[0045] The arithmetic mean roughness Ra of the first main surface 121 of the substrate 12 for antenna installation is preferably 1.2 μm or less. This is because if the arithmetic mean roughness Ra of the first main surface 121 is 1.2 μm or less, as will be described later, air easily flows in the space S formed between the substrate 12 for antenna installation and the glass plate 20. The arithmetic mean roughness Ra of the first main surface 121 is more preferably 0.6 μm or less, and even more preferably 0.3 μm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but for example, it is 0.001 μm or more.

[0046] Note that the arithmetic mean roughness Ra can be measured based on Japanese Industrial Standard JIS B0601:2001.

[0047] When the antenna 11 is a flat antenna, the arithmetic mean roughness Ra of the main surface on the glass plate side of the antenna 11 is preferably 1.2 μm or less, more preferably 0.6 μm or less, and even more preferably 0.3 μm or less. Also, when the antenna 11 is provided inside the housing container, the arithmetic mean roughness Ra of the main surface on the glass plate side of the housing container is preferably 1.2 μm or less, more preferably 0.6 μm or less, and even more preferably 0.3 μm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but for example, it is 0.001 μm or more.

[0048] The fixing portion 13A forms a space S between the glass plate 20 and the substrate 12 for antenna installation, through which air can flow, and is for fixing the substrate 12 for antenna installation to the glass plate 20. The fixing portion 13A is attached to the first main surface 121 of the substrate 12 for antenna installation. In the present embodiment, the fixing portion 13A is provided in a rectangular shape along the Z-axis direction at both ends of the substrate 12 for antenna installation in the X-axis direction. In the present embodiment, a space S through which air flows is formed between the glass plate 20 and the substrate 12 for antenna installation in order to suppress a local increase in the surface temperature of the glass plate 20 at a position facing the substrate 12 for antenna installation. When sunlight irradiates the outer main surface of the glass plate 20, the glass plate 20 is heated. At this time, if the flow of air is obstructed near the antenna unit 10, the temperature of the antenna unit 10 rises, so the temperature of the surface of the glass plate 20 to which the antenna unit 10 is attached tends to rise more easily than the temperature of the other surfaces of the glass plate 20. In order to suppress this temperature rise, the space S is formed between the glass plate 20 and the substrate 12 for antenna installation. Details regarding this point will be described later.

[0049] The material for forming the fixing portion 13A is not particularly limited as long as it can be fixed to the contact surfaces of the substrate 12 for antenna installation and the glass plate 20. For example, an adhesive or an elastic seal can be used. As the material for forming the adhesive or the sealing material, for example, known resins such as silicone-based resins, polysulfide-based resins, or acrylic-based resins can be used. Further, the fixing portion 13A may be formed of a metal such as aluminum or a spacer formed of a resin such as AES (acrylonitrile·ethylene·styrene copolymer). When using a spacer, for example, the spacer is fixed to the contact surfaces of the substrate 12 for antenna installation and the glass plate 20 with an adhesive such as a silicone sealant.

[0050] The average thickness t of the fixing portion 13A is preferably 0.5 mm to 100 mm. If the average thickness t is too small, the thickness of the space S formed by the substrate 12 for antenna installation and the glass plate 20 becomes small (thin), and air cannot flow smoothly in the space S. Note that by making the space S between the substrate 12 for antenna installation and the glass plate 20 small, the thickness of the space S becomes thin, but the space S can function as a heat insulation layer. Also, even if the thickness of the space S is small, a certain amount of air flows. That is, when sunlight irradiates the glass plate 20, the temperature of the glass plate 20 rises, and the temperature of the air in the space S also rises. And as the temperature of the air rises, the air expands more, so as a result, the air above in the space S rises and flows out from the upper side of the space S to the outside. Then, air sequentially rises from the lower side in the space S. Therefore, even when the thickness of the space S is small, as the temperature of the air in the space S rises, the air tends to flow.

[0051] On the other hand, when the average thickness t of the fixing portion 13A is increased, the space S becomes larger (thicker) accordingly, so the air flow in the space S becomes more suitable. However, since the distance between the main surface of the glass plate 20 and the substrate 12 for antenna installation increases (becomes larger), there is a possibility of hindering the electromagnetic wave transmission performance. Also, since the antenna unit 10 protrudes greatly from the main surface of the glass plate 20, the antenna unit 10 becomes an obstacle to the glass plate 20.

[0052] If the average thickness t of the fixing portion 13A is within the above range, due to a slight temperature rise, the air flowing into the space S can pass through the space S. Thereby, the glass plate 20 can be suppressed from being warmed by the air flowing through the space S, so that the over-temperature rise of the first main surface 121 of the substrate 12 for antenna installation can be suppressed.

[0053] The average thickness t of the fixing portion 13A is more preferably 2 mm to 16 mm, still more preferably 4 mm to 14 mm, and particularly preferably 6 mm to 12 mm. The average thickness t of the fixing portion 13A may be 2 mm or more, 4 mm or more, 6 mm or more, 15 mm or more, 20 mm or more, 30 mm or more, or 50 mm or more in order to suppress thermal cracking. Also, the average thickness t of the fixing portion 13A may be 80 mm or less, 60 mm or less, or 55 mm or less in order to improve the design property.

[0054] In this embodiment, the thickness refers to the length in the vertical direction (Y-axis direction) of the fixing portion 13A with respect to the contact surface of the substrate 12 for antenna installation and the glass plate 20. In this embodiment, the average thickness t of the fixing portion 13A refers to the average value of the thickness of the fixing portion 13A. For example, in the cross section of the fixing portion 13A, when measured at several locations (for example, about 3 locations) at arbitrary places in the Z-axis direction, it refers to the average value of the thicknesses of these measurement locations.

[0055] When the substrate 12 for antenna installation has an angle with respect to the glass plate 20 (window glass), the fixing portion 13A may be configured in a trapezoidal shape in cross section.

[0056] When the substrate 12 for antenna installation has an angle with respect to the glass plate 20 (window glass), the shortest value of the thickness of the fixing portion 13A is preferably 0.5 mm to 100 mm. Also, the shortest value of the thickness of the fixing portion 13A may be 2 mm or more, 4 mm or more, 6 mm or more, 15 mm or more, 20 mm or more, 30 mm or more, or 50 mm or more in order to suppress thermal cracking. The shortest value of the thickness of the fixing portion 13A may be 80 mm or less, 60 mm or less, or 55 mm or less in order to improve the design property.

[0057] As described above, the space S is a space formed between the glass plate 20 and the substrate 12 for antenna installation by the fixing portion 13A, allowing air to flow. Therefore, the thickness of the space S is substantially the same as the average thickness t of the fixing portion 13A.

[0058] In addition, when the main surface of the glass plate 20 is, for example, in a situation where in addition to sunlight irradiation, a heat source is installed near the glass plate 20, the temperature rise may not be sufficiently suppressed only by the amount of air flowing naturally in the space S. In that case, air may be forcibly blown into the space S. The air volume per unit area of the substrate 12 for antenna installation blown into the space S (hereinafter, also simply referred to as the air volume) is 2 m 3 / hour or more is preferable. If the air volume is 2 m 3 / hour (hour) or more, it is possible to reduce the temperature rise of the main surface of the glass plate 20 located at the position facing the substrate 12 for antenna installation. The air volume is more preferably 5 m 3 / hour or more. The upper limit of the air volume is not particularly limited, but for example, it is 10 m 3 / hour or less. As a means for forcibly blowing air into the space S, for example, a blower may be used.

[0059] In this way, by forming the space S, the antenna unit 10 can reduce the average solar radiation absorption rate of the first main surface 121 of the substrate 12 for antenna installation. Thereby, it is possible to suppress the surface temperature of the glass plate 20 from rising. The average solar radiation absorption rate of the first main surface 121 of the substrate 12 for antenna installation depends on the size of the substrate 12 for antenna installation, the thickness of the space S, etc., and is preferably 60% or less, more preferably 40% or less, and still more preferably 25% or less.

[0060] In the present embodiment, the average solar radiation absorption rate refers to the average value of the solar radiation absorption rates of the first main surface 121 of the substrate 12 for antenna installation. For example, in the portion of the first main surface 121 having the antenna and the portion not having the antenna, the areas are obtained, and the solar radiation absorption rates are measured at several locations (e.g., three locations) at arbitrary positions respectively, whereby the average value of the solar radiation absorption rates can be obtained. The solar radiation absorption rate can be obtained according to JIS R 3106 (1998).

[0061] When the antenna 11 is a flat plate antenna, the average solar radiation absorption rate of the main surface on the glass plate side of the antenna 11 is preferably 60% or less, more preferably 40% or less, and still more preferably 25% or less. When the antenna 11 is provided inside the housing container, the average solar radiation absorption rate of the main surface on the glass plate side of the housing container is preferably 60% or less, more preferably 40% or less, and still more preferably 25% or less.

[0062] In the antenna unit 10, air flows into the space S from below the substrate 12 for antenna installation (in the -Z axis direction). The air flowing into the space S can freely flow in the space S toward the upper side (+Z axis direction) of the substrate 12 for antenna installation. The air flowing through the space S flows out from the upper side (+Z axis direction) of the substrate 12 for antenna installation while contacting the main surface of the glass plate 20 located at a position facing the substrate 12 for antenna installation. By the air in the space S contacting the main surface of the glass plate 20 located at a position facing the substrate 12 for antenna installation, it is possible to suppress the main surface of the glass plate 20 located at a position facing the substrate 12 for antenna installation from being excessively heated by the outside air, sunlight, etc. Also, since the fixing portion 13A is continuously formed in the vertical direction, accordingly, the temperature difference between the upper part and the lower part in the space S becomes larger. Therefore, due to the so-called chimney effect, the flow velocity of the air flowing through the space S can be increased.

[0063] The antenna unit 10 is provided with a fixing portion 13A on the antenna installation substrate 12 so that a space S in which air can flow is formed between the glass plate 20 and the antenna installation substrate 12. Thereby, even when the glass plate 20 is heated by outside air, sunlight, or the like, it is possible to suppress an excessive temperature rise of the main surface of the glass plate 20 located at a position facing the antenna installation substrate 12. Therefore, it is possible to reduce the possibility of thermal cracking occurring in the glass plate 20 at a position facing the antenna installation substrate 12. Thus, the antenna unit 10 can be stably installed on the glass plate 20 without causing damage to the glass plate 20.

[0064] Next, another form of the antenna unit 10 will be described.

[0065] So far, the embodiment in which the fixing portions 13A are provided at two locations on the antenna installation substrate 12 has been described. However, as long as air can flow in the space S, the form of the fixing portion 13A is not limited. An example of another form of the fixing portion 13A is shown in FIG. 4. FIG. 4 is a transparent perspective view showing an example of another form of the fixing portion 13A. As shown in FIG. 4, the fixing portion 13B may be provided at both ends in the X-axis direction of the first main surface 121 of the antenna installation substrate 12 and at both ends in the Z-axis direction thereof, and the antenna installation substrate 12 may be fixed at four locations. Further, among the four fixing portions 13B, the fixing portion 13B provided in the -Z-axis direction may be only one, for example, near the center of the lower end of the antenna installation substrate 12, and the antenna installation substrate 12 may be fixed to the glass plate 20 with three fixing portions 13B. Further, only two of the four fixing portions 13B that are diagonally located may be used, and the antenna installation substrate 12 may be fixed to the glass plate 20 with two fixing portions 13B.

[0066] The fixing portion may be provided over the entire side of the antenna installation substrate 12 as shown in FIG. 3, or may be provided on a part of the side of the antenna installation substrate 12 as shown in FIG. 4.

[0067] Also, in FIG. 3, the fixing portions 13A are provided in a rectangular shape along the Z-axis direction at both ends of the antenna installation substrate 12 in the X-axis direction. However, if air can flow in the space S, they may be provided at three locations out of both ends in the X-axis direction and both ends in the Z-axis direction of the antenna installation substrate 12. When the fixing portions 13A are provided at three locations, for example, as described above, by forcibly ventilating the air in the space S using a blower, the air can be made to flow in the space S. If the fixing portions are provided in a frame shape along the four sides of the antenna installation substrate 12, the air cannot flow in the space S. However, by forming the fixing portions in the above-described form, the air can flow in the space S.

[0068] In the present embodiment, the antenna unit 10 forms only the space S between the glass plate 20 and the first main surface 121 of the antenna installation substrate 12, but is not limited thereto. A cross-sectional state of an example of another form of the antenna unit is shown in FIG. 5. As shown in FIG. 5, the antenna unit 10 may further have a dielectric layer 15 on the first main surface 121 on the glass plate 20 side of the antenna installation substrate 12. Even in this case, a space S is formed between the glass plate 20 and the dielectric layer 15. The dielectric layer 15 may cover the entire first main surface 121 or only the portion corresponding to the antenna installation substrate 12. By providing the dielectric layer 15 on the first main surface 121 of the antenna installation substrate 12, the transmission performance of electromagnetic waves can be enhanced. The dielectric layer 15 may be a single layer or a plurality of layers.

[0069] The dielectric layer 15 preferably has a relative permittivity between the antenna installation substrate 12 and the space S. The relative permittivity of the dielectric layer 15 is preferably, for example, 5.0 or less, and more preferably 3.5 or less. The material for forming the dielectric layer 15 may be any material having a relative permittivity between the antenna installation substrate 12 and the space S. For example, (meth)acrylic resins, polycarbonate resins, polyvinyl chloride resins, fluorine resins, fiber reinforced plastics (FRP), etc. can be used. The dielectric layer 15 can be formed by a known method such as being attached with an adhesive.

[0070] The thickness of the dielectric layer 15 only needs to be able to be disposed between the glass plate 20 and the substrate 12 for antenna installation. For example, it is preferably 0.2 mm to 1.5 mm, more preferably 0.3 mm to 1.3 mm, and even more preferably 0.7 mm to 1.2 mm. In this case, the fixing portion 13A is set to 0.7 mm to 100 mm so that the space S can be formed.

[0071] When the dielectric layer 15 is provided on the first main surface 121 of the substrate 12 for antenna installation, the arithmetic mean roughness Ra of the dielectric layer 15 is preferably the same as the arithmetic mean roughness Ra of the first main surface 121 of the substrate 12 for antenna installation. The upper limit value of the arithmetic mean roughness Ra of the dielectric layer 15 is preferably 1.2 μm or less, more preferably 0.6 μm or less, and even more preferably 0.3 μm or less. The lower limit value of the arithmetic mean roughness Ra is not particularly limited, but is preferably 0.001 μm or more. In this case, the arithmetic mean roughness Ra of the first main surface 121 of the glass plate 20 is not particularly limited.

[0072] In the present embodiment, as shown in FIG. 6, the antenna unit 10 may have an electromagnetic shielding layer 16 provided on the second main surface 122 of the substrate 12 for antenna installation, which is opposite to the glass plate 20 side. The electromagnetic shielding layer 16 can reduce the electromagnetic wave interference between the electromagnetic wave and the electromagnetic wave generated from indoor electronic devices. The electromagnetic shielding layer 16 may be a single layer or multiple layers. As the electromagnetic shielding layer 16, known materials can be used. For example, a metal film such as copper or tungsten, or a transparent substrate using a transparent conductive film can be used.

[0073] As the transparent conductive film, for example, a light-transmissive conductive material such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium zinc oxide (IZO), indium tin oxide added with silicon oxide (ITSO), zinc oxide (ZnO), or a Si compound containing P or B can be used.

[0074] The electromagnetic shielding layer 16 is preferably formed in a mesh shape to have light transmissivity. Here, the mesh refers to a state in which mesh-shaped through-holes are formed in the plane of the electromagnetic shielding layer 16. When the electromagnetic shielding layer 16 is formed in a mesh shape, the mesh openings may be square or diamond-shaped. The line width of the mesh is preferably 5 to 30 μm, more preferably 6 to 15 μm. The line interval of the mesh is preferably 50 to 500 μm, more preferably 100 to 300 μm.

[0075] As a method for forming the electromagnetic shielding layer 16, known methods can be used, for example, a sputtering method or a vapor deposition method can be used.

[0076] The surface resistivity of the electromagnetic shielding layer 16 is preferably 20 Ω / square or less, more preferably 10 Ω / square or less, and even more preferably 5 Ω / square or less. The size of the electromagnetic shielding layer 16 is preferably equal to or larger than the size of the substrate 12 for antenna installation. By providing the electromagnetic shielding layer 16 on the second main surface 122 side of the substrate 12 for antenna installation, the transmission of radio waves into the room can be suppressed. The surface resistivity of the electromagnetic shielding layer 16 depends on the thickness, material, and aperture ratio of the electromagnetic shielding layer 16. The aperture ratio is the ratio of the area of the openings per area including the openings of the electromagnetic shielding layer 16.

[0077] The visible light transmittance of the electromagnetic shielding layer 16 is preferably 40% or more, more preferably 60% or more, from the viewpoint of improving the design property. Also, the visible light transmittance of the electromagnetic shielding layer 16 is preferably 90% or less, more preferably 80% or less, in order to suppress the transmission of radio waves into the room.

[0078] Also, the larger the aperture ratio of the electromagnetic shielding layer 16, the higher the visible light transmittance. The aperture ratio of the electromagnetic shielding layer 16 is preferably 80% or more, more preferably 90% or more. Also, the visible light aperture ratio of the electromagnetic shielding layer 16 is preferably 95% or less in order to suppress the transmission of radio waves into the room.

[0079] The thickness of the electromagnetic shielding layer 16 is preferably 400 nm or less, more preferably 300 nm or less. The lower limit of the thickness of the electromagnetic shielding layer 16 is not particularly limited, and may be 2 nm or more, may be 10 nm or more, or may be 30 nm or more.

[0080] Moreover, when the electromagnetic shielding layer 16 is formed in a mesh shape, the thickness of the electromagnetic shielding layer 16 may be 2 to 40 μm. By forming the electromagnetic shielding layer 16 in a mesh shape, even if the electromagnetic shielding layer is thick, the visible light transmittance can be increased.

[0081] Note that the electromagnetic shielding layer 16 is not limited to the example of being provided on the second main surface 122. For example, the antenna unit 10 sets a tilt angle in a direction that forms an angle with respect to the normal direction (the positive direction of the Y axis) of the surface formed by the antenna unit 10. In this case, a part of the radiated electromagnetic wave is reflected at an angle with respect to the normal direction (for example, the negative direction of the Y axis) of the interface between the glass plate 20 and the outside. For example, the reflected wave that forms an angle with respect to the negative direction of the Y axis may pass through the glass plate 20 from a region different from the region where the antenna unit 10 is provided on the indoor side (the negative direction side of the Y axis) into the room. In order to prevent such a reflected wave from passing into the room, the electromagnetic shielding layer 16 may be provided in a region different from the region where the antenna unit 10 is provided on the indoor side surface of the glass plate 20. For example, the electromagnetic shielding layer 16 may be provided in the positive and / or negative directions of the Z axis with respect to the region where the antenna unit 10 is provided on the indoor side surface of the glass plate 20. The position and / or region where the electromagnetic shielding layer 16 is provided with respect to the glass plate 20 may be set according to at least one of the height where the antenna unit 10 is provided, the area formed by the antenna unit 10, and the radiation direction (for example, the tilt angle) of the antenna unit 10.

[0082] Moreover, when the electromagnetic shielding layer 16 is provided on the indoor side of the glass plate 20, a space similar to the space S may be formed between the glass plate 20 and the electromagnetic shielding layer 16.

[0083] Instead of the electromagnetic shielding layer 16, a structure that suppresses the transmission of electromagnetic waves into the room while maintaining translucency may be provided on the second main surface 122. For example, one or more electromagnetic wave absorbing elements may be provided on the second main surface 122. The electromagnetic wave absorbing element has, for example, a structure in which metal is formed into a linear (long) shape.

[0084] Note that the electromagnetic wave absorbing element is not limited to metal, and may be a material composed of a plurality of raw materials. For example, the plurality of raw materials may be metal, alloy, carbon, and / or various organic substances, etc., and their respective conductivity may be different. Also, the electromagnetic wave absorbing element may be configured using a translucent material.

[0085] A plurality of electromagnetic wave absorbing elements may be arranged on the second main surface 122, for example, such that their longitudinal directions face the same direction and they are arranged at a predetermined interval in a direction perpendicular to the longitudinal direction. For example, the longitudinal direction of the electromagnetic wave absorbing element may be arranged along the direction of the polarization plane of the electromagnetic wave radiated from the antenna unit 10.

[0086] The electromagnetic wave absorbing element is not limited to the example of being provided on the second main surface 122, and may be provided, for example, in a region different from the region where the antenna unit 10 is provided on the indoor side surface of the glass plate 20. The position and / or range where the electromagnetic wave absorbing element is provided may be set according to at least one of the height at which the antenna unit 10 is provided, the area formed by the antenna unit 10, and the radiation direction (e.g., tilt angle) of the antenna unit 10.

[0087] In this embodiment, the antenna unit 10 is attached to the glass plate 20 with the antenna installation substrate 12 and the fixing portion 13A integrated, but it is not limited to this. For example, only the fixing portion 13A may be attached to the glass plate 20 first, and then the antenna installation substrate 12 may be attached to the fixing portion 13A to complete the antenna unit 10 on the glass plate 20.

[0088] <Glass plate with antenna> An antenna-equipped glass plate to which an antenna unit for glass according to an embodiment is applied will be described. FIG. 7 is a perspective view of the antenna-equipped glass plate, and FIG. 8 is a partial cross-sectional view taken along the line A-A in FIG. 7. As shown in FIGS. 7 and 8, the antenna-equipped glass plate 30 has the above-described antenna unit 10 and a glass plate 31, and the antenna unit 10 is attached to the glass plate 31.

[0089] The glass plate 31 is a known glass plate used for windows of buildings and the like. The glass plate 31 shown in FIGS. 7 and 8 is formed in a rectangular shape in a plan view and has a first main surface 311 and a second main surface 312. The thickness of the glass plate 31 is set according to the requirements of buildings and the like. In the present embodiment, the first main surface 311 of the glass plate 31 is the outdoor side, and the second main surface 312 is the indoor side. In the present embodiment, the first main surface 311 and the second main surface 312 may be simply referred to as the main surface in some cases. In the present embodiment, the rectangle includes not only a rectangle and a square but also a shape in which the corners of the rectangle and the square are chamfered. The shape of the glass plate 31 in a plan view is not limited to a rectangle and may be a circle or the like. Further, the glass plate 31 is not limited to a single plate and may be laminated glass or multilayer glass.

[0090] Examples of the material of the glass plate 31 include soda lime silica glass, borosilicate glass, aluminosilicate glass, or alkali-free glass.

[0091] The glass plate 31 can be manufactured using a known manufacturing method such as a float method, a fusion method, a redraw method, a press molding method, or a drawing method. As the manufacturing method of the glass plate 31, it is preferable to use the float method in terms of excellent productivity and cost.

[0092] The glass plate 31 is formed in a rectangular shape in a plan view, for example. Examples of the cutting method of the glass plate 31 include a method of irradiating a laser beam on the surface of the glass plate 31 and moving the irradiation region of the laser beam on the surface of the glass plate 31 to cut it, or a method of mechanically cutting it with a cutter wheel or the like.

[0093] The outer edge of the glass plate 31 is held in a state of being sandwiched by the window frame 33. The glass plate 31 may be held to the window frame 33 by using an adhesive or the like at the outer edge of the glass plate 31. As the material for forming the window frame 33, known materials can be used. For example, metal materials such as stainless steel and aluminum can be used.

[0094] The antenna unit 10 is preferably provided at a position separated from the window frame 33 by a predetermined distance L or more in a plan view. The predetermined distance L is preferably 20 mm. For example, when the window glass is directly exposed to sunlight, the temperature of the glass plate 31 rises and becomes high. On the other hand, since the temperature of the window frame 33 is lower than that of the glass plate 31, the glass plate 31 located within the window frame 33 has a lower temperature than the window frame 33. That is, the portion of the glass plate 31 facing the antenna unit 10 has a higher temperature than the portion of the glass plate 31 located within the window frame 33. Therefore, a large thermal expansion difference occurs between the portion of the glass plate 31 facing the antenna unit 10 and the portion of the glass plate 31 located within the window frame 33, and a large thermal strain occurs in the portion of the glass plate 31 facing the antenna unit 10. In some cases, there is a possibility that thermal cracks may occur in the portion of the glass plate 31 facing the antenna unit 10 or in the vicinity thereof. In particular, by attaching the antenna unit 10 to the second main surface 312 of the glass plate 31, the air flow on the second main surface 312 of the glass plate 31 at the position facing the antenna unit 10 is obstructed. In this case, the temperature of the portion of the glass plate 31 facing the antenna unit 10 becomes even higher. As a result, the thermal strain generated in the portion of the glass plate 31 facing the antenna unit 10 or in the vicinity thereof may become even larger.

[0095] Here, an example of the relationship between the position of the antenna unit 10 from the inner frame of the window frame 33 attached to the glass plate 31 and the stress (maximum tensile stress) generated in the glass plate 31 is shown in FIG. 9. In FIG. 9, the size of the antenna unit 10 is 400 mm in width (X-axis direction) × 400 mm in height (Z-axis direction). The average solar radiation absorption rate of the antenna installation substrate 12 is about 90%. The glass plate 31 is FL-8 (manufactured by Asahi Glass Co., Ltd.). The maximum tensile stress generated in the glass plate 31 is evaluated by the ratio (maximum tensile stress ratio) of the maximum tensile stress generated in the glass plate 31 to which the antenna unit 10 is attached and the maximum tensile stress generated in the glass plate 31 to which the antenna unit 10 is not attached. The vertical axis in FIG. 9 indicates the maximum tensile stress ratio of the glass plate 31. The horizontal axis in FIG. 9 is the distance of the antenna unit 10 from the inner frame of the window frame 33.

[0096] As shown in FIG. 9, when the antenna unit 10 is at a position about 20 mm from the inner frame of the window frame 33, the maximum tensile stress ratio reaches the maximum value (about 1.4), and the thermal distortion generated in the glass plate 31 becomes the largest. Then, as the installation position of the antenna unit 10 moves away from the inner frame of the window frame 33 by more than 20 mm, the maximum tensile stress ratio tends to decrease. Therefore, if the antenna unit 10 is installed at a position more than 20 mm away from the inner frame of the window frame 33, the thermal distortion generated in the glass plate 31 will be reduced. Also, if the antenna unit 10 is more than 20 mm from the inner frame of the window frame 33, since the antenna unit 10 is at a position away from the window frame 33, it is easier to install the antenna unit 10, which is preferable.

[0097] In this embodiment, by providing the antenna unit 10 at a position more than 20 mm away from the window frame 33, the temperature gradient between the portion of the glass plate 31 facing the antenna unit 10 and the portion of the glass plate 31 located within the window frame 33 can be reduced. Further, air flow is generated in the space S formed between the antenna installation substrate 12 of the antenna unit 10 and the glass plate 31. Thereby, the temperature gradient between the portion of the glass plate 31 facing the antenna unit 10 and the portion of the glass plate 31 located within the window frame 33 can be made even smaller.

[0098] The predetermined distance L is more preferably 25 mm, even more preferably 30 mm, particularly preferably 40 mm, and most preferably 50 mm. That is, the antenna unit 10 is more preferably provided at a position more than 25 mm away from the window frame 33 in plan view, even more preferably at a position more than 30 mm away, particularly preferably at a position more than 40 mm away, and most preferably at a position more than 50 mm away.

[0099] Since the glass plate 30 with an antenna includes the antenna unit 10, the possibility of thermal cracking occurring in the portion of the glass plate 31 facing the antenna unit 10 can be reduced. Therefore, the glass plate 30 with an antenna can be suitably used as a glass plate for window glass in existing or newly constructed buildings, houses, etc.

[0100] The glass plate 30 with an antenna can have the antenna unit 10 provided on the second main surface 312, which is the indoor side of the glass plate 31. Thereby, it is possible to prevent the antenna unit 10 from spoiling the appearance of the building and to prevent it from being exposed to the outside air, so that the durability can be improved. Further, the glass plate 30 with an antenna has the antenna unit 10 provided above the glass plate 31 and on one of the left and right end sides. Therefore, by passing the wiring connected to the antenna installation substrate 12 of the antenna unit 10 from the glass plate 31 to the ceiling space or the wall, etc., the wiring exposed on the glass plate 20 or the indoor wall of the building can be reduced.

[0101] Since the glass plate 30 with an antenna is provided with the antenna unit 10 on the glass plate 31, it is not necessary to install it on the rooftop of a building or the like. Therefore, the glass plate 30 with an antenna can eliminate the need for work for installation at a high place such as the rooftop of a building, and thus can be easily installed on the building. Also, for example, even when the antenna unit 10 is damaged and needs to be replaced, the antenna unit 10 can be easily replaced in a short time.

[0102] The glass plate 30 with an antenna can be provided with a large number of antenna units 10 on the glass plate 31. Even in this case, since the antenna units 10 are provided on the second main surface 312 which is the indoor side of the glass plate 31, even if a large number of antenna units 10 are provided on the glass plate 31, the glass plate 30 with an antenna can reduce the damage to the appearance of the building. Also, the glass plate 30 with an antenna can stably transmit and receive electromagnetic waves by providing a large number of antenna units 10 on the glass plate 31.

[0103] As the antenna is miniaturized, it can also be installed inside a building. When installing the antenna in a building, it is installed while selecting an appropriate installation location for the antenna so that electromagnetic waves can be stably transmitted and received without damaging the appearance of the building.

[0104] In order to achieve high speed and large capacity of wireless communication, the frequency band used is becoming higher in frequency and wider in bandwidth, such as the frequency band for the fifth generation mobile communication system (5G). Therefore, when electromagnetic waves having a high-frequency and wide-band frequency band are used for mobile phones, Internet communication, etc., it is important to install a larger number of antennas than in the past in order to stably transmit and receive electromagnetic waves. Note that the 5G frequency band means frequencies from 3.6 to 29.5 GHz including the 3.7 GHz band (3.6 - 4.2 GHz), 4.5 GHz band (4.4 - 4.9 GHz), and 28 GHz band (27.5 - 29.5 GHz).

[0105] According to this embodiment, the glass plate 30 with an antenna can stably transmit and receive electromagnetic waves while reducing the damage to the appearance of the building by providing a large number of antenna units 10 on the glass plate 31. As a result, since electromagnetic waves with high frequencies and wide frequency bands can be stably transmitted and received, it is possible to cope with the high speed and large capacity of wireless communication.

[0106] (Other embodiments) Hereinafter, other embodiments of the glass plate 30 with an antenna will be described.

[0107] In this embodiment, as shown in FIG. 10, the glass plate 30 with an antenna may be provided with a coating layer 35 having a heat ray reflection function or the like on the glass plate 31. In this case, the coating layer 35 preferably has an opening 351A at a position facing the antenna installation substrate 12 of the antenna unit 10 or a flat antenna. Thereby, the glass plate 30 with an antenna can suppress the deterioration of the radio wave transmission performance.

[0108] The opening 351A is preferably at least the same size as the antenna installation substrate 12 or the flat antenna.

[0109] When the antenna is provided inside the housing container, the coating layer 35 preferably has an opening 351A at a position facing the housing container of the antenna unit 10, and the opening 351A is preferably at least the same size as the housing container.

[0110] As the coating layer 35, for example, a conductive film can be used. As the conductive film, for example, a transparent dielectric, a metal film, a laminated film obtained by sequentially laminating a transparent dielectric, ITO, or fluorine-doped tin oxide (FTO) can be used. As the metal film, for example, a film mainly composed of at least one selected from the group consisting of Ag, Au, Cu, and Al can be used.

[0111] The area of the opening 351A is preferably not less than the value of the following formula (1). Thereby, the glass plate 30 with an antenna can further suppress the decrease in radio wave transmission performance. a × b ···(1) (However, in formula (1), a is the length of one side of the substrate 12 for antenna installation, the flat antenna, or the housing container, and b is the length of the other side of the substrate 12 for antenna installation, the flat antenna, or the housing container.)

[0112] Here, a and b in the above formula (1) are the cases where the substrate 12 for antenna installation, the flat antenna, or the housing container is rectangular in plan view, but it is not limited thereto. When the substrate 12 for antenna installation is circular in plan view, a and b in the above formula (1) are the diameters of the substrate 12 for antenna installation, the flat antenna, or the housing container and can be the same value. When the substrate 12 for antenna installation is elliptical in plan view, a in the above formula (1) can be the minor axis of the substrate 12 for antenna installation, the flat antenna, or the housing container, and b can be the major axis.

[0113] Also, when the antenna 11 is provided inside the substrate 12 for antenna installation, a in the above formula (1) is the length of one side of the substrate 12 for antenna installation, and b is the length of the other side of the substrate 12 for antenna installation, as in the above case. When the antenna 11 is provided inside a housing container having a surface parallel to the glass plate 20, a in the above formula (1) is the length of one side of the housing container, and b is the length of the other side of the housing container. When the antenna 11 is formed in a flat plate shape, a in the above formula (1) is the length of one side of the flat antenna, and b is the length of the other side of the flat antenna.

[0114] The opening 351A may be partially left, other than having a size corresponding to the antenna unit 10. Another example of the form of the opening 351A is shown in FIG. 11. As shown in FIG. 11, the coating layer 35 may have an opening 351B formed in a slit shape. Even in this case, the glass plate 30 with an antenna can suppress a decrease in radio wave transmission performance. Note that the size of the opening 351B is formed such that the fixing portion 13A of the antenna unit 10 is positioned on the outer periphery thereof.

[0115] The width of the slit-shaped opening 351B is preferably λ / 200 or more. The slit-shaped opening 351B does not need to have a periodic structure, but the interval between the slit-shaped openings 351B is preferably λ / 2 or less. The slit-shaped opening 351B is preferably formed perpendicular to the electric field direction of the electromagnetic wave. Thereby, the glass plate 30 with an antenna can more stably suppress a decrease in radio wave transmission performance. When using both horizontal polarization and vertical polarization as electromagnetic waves, the opening 351B is preferably formed in a grid shape. Thereby, the glass plate 30 with an antenna can more stably suppress a decrease in radio wave transmission performance. Note that when removing the coating layer 35 in an irregular shape, it is preferable not to make the interval between the slit-shaped openings 351B continuous at λ / 2 in the electric field direction. Thereby, the glass plate 30 with an antenna can suppress a decrease in radio wave transmission performance.

[0116] As shown in FIG. 12, the glass plate 30 with an antenna may have a water-repellent treatment layer 36 on the first main surface 311 on the side opposite to the antenna unit 10 side (outer side) of the glass plate 31. By providing the water-repellent treatment layer 36 on the first main surface 311, the radio wave transmission performance of the glass plate 20 can be improved.

[0117] <Construction and manufacturing method of glass antenna unit> Next, a construction and manufacturing method of the antenna unit according to an embodiment will be described. Note that the construction and manufacturing method of the antenna unit described here can be applied to window glass (glass plate) of a building after construction or window glass (glass plate) of a newly constructed building.

[0118] First, conduct a site inspection in advance for attaching the antenna unit 10 to the window glass of the building. The site inspection includes, for example, selecting the type of glass and confirming the orientation of the installation location, and then confirming the radio wave characteristics of the window glass 40 of the building. By conducting the site inspection, the attachment position of the fixing part 13A, or the thickness of the fixing part 13A (the thickness of the space S), etc. are determined.

[0119] After that, as shown in FIG. 13, attach the antenna unit 10 to the window glass 40 via the fixing part 13A so that a space S where air can flow is formed between the window glass 40 and the antenna installation substrate 12.

[0120] Thereby, the antenna unit 10 as shown in FIG. 2 can be installed on the window glass 40 of the existing building.

[0121] In addition, the construction and manufacturing method of the antenna unit 10 can also be applied to the glass plate 31 provided with a coating layer 35 (see FIG. 10) having a heat ray reflection function or the like on the second main surface 312 which is the indoor side of the glass plate 31. In this case, as shown in FIGS. 10 and 11, remove the coating layer 35 at least at the position of the glass plate 31 corresponding to the antenna installation substrate 12 of the antenna unit 10. And it is preferable to form an opening 351A as shown in FIG. 10 or a slit-shaped opening 351B as shown in FIG. 11. Thereby, since the opening 351A or the opening 351B has at least the same size as the antenna unit 10, the glass plate 30 with an antenna can suppress the decrease in radio wave transmission performance.

[0122] The timing of forming the openings 351A and 351B is not particularly limited. However, for example, from the viewpoint of the ease of forming the openings 351A and 351B, it is preferable to form the openings 351A and 351B before attaching the antenna unit 10 to the window glass 40 of the building.

[0123] The coating layer 35 can be removed by a known method such as polishing or laser.

[0124] As described above, it is preferable that the openings 351A and 351B are formed such that their areas are equal to or greater than the value of the above formula (1). Thereby, the glass plate 30 with an antenna can further suppress a decrease in radio wave transmission performance.

[0125] <Method for manufacturing a glass plate with an antenna> Next, a method for manufacturing the glass plate 30 with an antenna will be described. First, an antenna unit 10 and a rectangular glass plate 31 having a main surface formed thereon are prepared. The glass plate 31 can be formed into a rectangle in plan view by using a known cutting method on a glass substrate obtained by a known manufacturing method.

[0126] Thereafter, the antenna unit 10 is attached to the glass plate 31 via the fixing portion 13A so that a space S through which air can flow is formed between the glass plate 31 and the antenna installation substrate 12.

[0127] Thereby, a glass plate 30 with an antenna as shown in FIG. 7 can be manufactured.

[0128] Also, a coating layer 35 (see FIG. 10) can be provided on the second main surface 312 of the glass plate 31. In this case, it is preferable to form an opening 351A as shown in FIG. 10 or a slit-shaped opening 351B as shown in FIG. 11 at a position of the coating layer 35 facing the antenna installation substrate 12 of the antenna unit 10.

Example

[0129] Hereinafter, an example in which an antenna unit is manufactured under the following conditions and a glass plate with an antenna is evaluated is shown. Examples 1-1 to 1-14 are examples, and Examples 1-15 to 1-17 are reference examples.

[0130] <Example 1> [Example 1-1] The size of the antenna installation substrate 12 (see FIG. 2) of the antenna unit 10 is set to a width (X-axis direction) of 400 mm × a height (Z-axis direction) of 400 mm, the average thickness of the fixing portion 13A (see FIG. 2) is set to 1.0 mm, and air is allowed to naturally ventilate in the space S (see FIG. 2). Thus, the glass plate 30 with an antenna shown in FIG. 7 was manufactured. As the antenna installation substrate 12 (see FIG. 2), those having an average solar radiation absorption rate of 20%, 40%, 60%, and 90% on the first main surface 121 were prepared. The amount of solar radiation irradiated on the glass plate 30 with an antenna is 825 W / m 2 , the outside air temperature of the building where the glass plate 30 with an antenna is installed is about 5°C, the indoor temperature is about 20°C, the heat transfer coefficient on the outside of the building is 15.1 W / m 2 k, the heat transfer coefficient on the inside of the building is 8.0 W / m 2 k, and the temperature of the window frame 33 of the glass plate 30 with an antenna was about 10.2°C. The temperature of the second main surface 312 on the side of the antenna installation substrate 12 of each antenna housing substrate, the air volume per unit area of the air flowing through the space S of the antenna installation substrate 12, and the stress generated at the edge of the glass plate 31 were measured.

[0131] The calculation of the stress generated at the edge of the glass plate 31 was performed based on the "Asahi Glass Plate Glass Building Materials Comprehensive Catalog Technical Data Edition". That is, the temperature t of the central portion of the glass plate 31 shown in FIG. 14 of each antenna installation substrate g , and the temperature t of the window frame 33 s were measured. Then, various coefficients (basic stress coefficient k0, shadow coefficient k1, curtain shadow coefficient k2, area coefficient k3, edge temperature coefficient f) were obtained.

[0132] The various coefficients are defined as follows. The basic stress coefficient k0 is 0.47 MPa / °C. When the solar radiation on the glass surface is not uniform and partial shadows are formed, the temperature distribution in the glass plate changes, and the thermal stress becomes larger compared to the case without shadows. The shadow coefficient k1 indicates the ratio of this stress increase compared to the case without shadows. Even if the solar radiation amount is the same, if there are curtains or blinds on the indoor side of the glass, the reflection and re-radiation of solar radiation by them will be enhanced. Therefore, compared with the case without them, the temperature at the center of the glass rises and the temperature difference becomes larger. The curtain shading coefficient k2 indicates this ratio. Even if the temperature difference is the same, when the glass area increases, the absolute value of the thermal expansion amount also increases, and the thermal stress becomes larger compared to the case where the glass area is small. The area ratio k3 indicates this as the ratio to a glass area of 1.0 m 2 is shown. The edge temperature coefficient f is defined by the following formula (i). f=(t g -t e ) / (t g -t s ) ···(i)

[0133] The various coefficients are selected considering the conditions of the glass plate 31 at that time from the values determined mainly based on experimental results. Then, using the temperature t g at the center of the glass plate 31, the temperature t s of the window frame 33, and the various coefficients, the stress σ generated at the edge of the glass plate 31 is calculated from the following formula (ii). σ=k0×k1×k2×k3×f×(t g -t s ) ···(ii)

[0134] [Example 1-2 and 1-3] In Example 1-1, an antenna-equipped glass plate 30 shown in Fig. 7 was fabricated in the same manner as in Example 1-1, except that the average thickness of the fixing portion 13A was changed to 2.0 mm or 3.0 mm. The temperature Tg of the second main surface 312 on the antenna installation substrate 12 side of the glass plate 31, the air volume per unit area of the antenna installation substrate 12 flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0135] [Example 1-4] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was fabricated in the same manner as in Example 1-1, except that the size of the substrate 12 for antenna installation was changed to a width (X-axis direction) of 400 mm and a height (Z-axis direction) of 800 mm, and the average thickness of the fixing portion 13A was changed to 6.0 mm. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0136] [Example 1-5] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was fabricated in the same manner as in Example 1-1, except that the size of the substrate 12 for antenna installation was changed to a width (X-axis direction) of 100 mm and a height (Z-axis direction) of 100 mm, and the average thickness of the fixing portion 13A was changed to 0.5 mm. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0137] [Example 1-6] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was fabricated in the same manner as in Example 1-1, except that the size of the substrate 12 for antenna installation was changed to a width (X-axis direction) of 100 mm and a height (Z-axis direction) of 100 mm. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0138] [Examples 1-7 and 1-8] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was produced in the same manner as in Example 1-1, except that the size of the substrate 12 for antenna installation was changed to a width (X-axis direction) of 100 mm × a height (Z-axis direction) of 100 mm, and the average thickness of the fixing portion 13A was changed to 2.0 or 3.0 mm. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0139] [Examples 1-9 to 1-11] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was produced in the same manner as in Example 1-1, except that air was forcedly ventilated in the space S using a blower and the air volume was changed. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0140] [Examples 1-12 to 1-14] In Example 1-1, an antenna-equipped glass plate 30 shown in FIG. 7 was produced in the same manner as in Example 1-1, except that the average thickness of the fixing portion 13A was changed to 5.0 mm, 15.0 mm, or 25.0 mm. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0141] [Example 1-15] Examples 1-15 are examples in which the substrate 12 for antenna installation is directly provided on the glass plate 31. In Example 1-1, an antenna-equipped glass plate 30 was produced in the same manner as in Example 1-1, except that the average thickness of the fixing portion 13A was set to 0.0 mm so that the space S was not formed. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air flow rate per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0142] [Example 1-16] Example 1-16 is an example in which the space S formed between the glass plate 31, the substrate 12 for antenna installation, and the glass is sealed. In Example 1-1, an antenna-equipped glass plate 30 was produced in the same manner as in Example 1-1, except that the space S was sealed so that air did not ventilate. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air flow rate per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0143] [Example 1-17] Example 1-17 is an example in which the space S formed between the glass plate 31, the substrate 12 for antenna installation, and the glass is sealed. In Example 1-1, an antenna-equipped glass plate 30 was produced in the same manner as in Example 1-1, except that the average thickness of the fixing portion 13A was set to 6.0 mm and the space S was sealed so that air did not ventilate. The temperature Tg of the second main surface 312 on the side of the substrate 12 for antenna installation of the glass plate 31, the air flow rate per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 were measured when the average solar radiation absorption rate of the antenna housing substrate was 20%, 40%, 60%, and 90%.

[0144] In each example, the size of the substrate 12 for antenna installation, the average thickness of the fixing portion 13A, the presence or absence of ventilation in the space S, the temperature of the second main surface 312 of the glass plate 31 on the side of the substrate 12 for antenna installation, the air volume per unit area of the substrate 12 for antenna installation flowing through the space S, and the stress generated at the edge of the glass plate 31 are shown in Table 1. Note that the hatched portions in Table 1 indicate portions where thermal cracking of the glass plate 31 may occur. As the stress that may cause thermal cracking in the glass plate 31, 17.7 MPa, which is the stress that the glass plate 31 can tolerate in a short period, was used as a reference.

[0145]

Table 1

[0146] As is clear from Table 1, in Examples 1-12 to 1-14, the average solar radiation absorption rate of the substrate 12 for antenna installation was 40% to 90%, the stress generated at the edge of the glass plate 31 was large, and there was a high possibility of thermal cracking in the glass plate 31. Therefore, it can be said that for a glass plate with an antenna as in Examples 1-12 to 1-14, it is necessary to take measures to prevent thermal cracking.

[0147] On the other hand, in Examples 1-1 to 1-14, generally, compared with Examples 1-15 to 1-17, the temperature of the glass plate 31 was lower and the stress generated at the edge of the glass plate 31 was smaller. This is considered to be because by providing the space S between the glass plate 31 and the substrate 12 for antenna installation so that air can flow, the temperature of the glass plate 31 could be lowered. In particular, when the average solar radiation absorption rate of the substrate 12 for antenna installation is less than 90%, the stress generated at the edge of the glass plate 31 is smaller than the stress (17.7 MPa) that the glass plate 31 can tolerate in a short period, and it can be said that the possibility of thermal cracking in the glass plate 31 can be reduced.

[0148] In addition, in Examples 1-9 to 1-11, the temperature of the glass plate 31 was lower, and the stress generated at the edge of the glass plate 31 was smaller. This can be attributed to the fact that by forcing air to flow through the space S, the temperature of the glass plate 31 could be reduced.

[0149] <Example 2> [Example 2-1] An antenna unit 10 was fabricated in which a dielectric layer 15 was provided on the first main surface 121 on the glass plate 31 side of the substrate 12 for antenna installation. This antenna unit 10 was attached to the glass plate 31 via a fixing portion 13A to fabricate a glass plate with an antenna. The first layer was the glass plate 31, the second layer was the space S, and the third layer was the dielectric layer. As the glass plate 31, soda-lime glass was used, and as the dielectric layer 15, it was formed using a polycarbonate-based resin. The thickness of the glass plate 31 was set to about 8.0 mm, the thickness of the space S was set to about 0.5 mm, and the thickness of the dielectric layer was set to about 10 mm. Electromagnetic waves were incident on the glass plate 31 from the direction opposite to the antenna unit 10 side of the fabricated glass plate 31, and the transmission loss (TL) of the electromagnetic waves was measured. As the electromagnetic waves, TE waves and TM waves were measured. The measurement results of the transmission loss of the TE waves are shown in FIG. 15, and the measurement results of the transmission loss of the TM waves are shown in FIG. 16. In FIGS. 15 and 16, the glass plate (60°) represents the transmission loss of the glass plate 31. Note that the relative permittivity of soda-lime glass is 7 - j0.1, the relative permittivity of air is 1.0, and the relative permittivity of the dielectric layer is 2.8 - j0.017.

[0150] [Example 2-2] In Example 2-1, an antenna unit 10 in which a dielectric layer 15 was provided on the first main surface 121 on the glass plate 31 side of the substrate 12 for antenna installation was fabricated. The electromagnetic wave transmission performance of the glass plate with an antenna was measured in the same manner as in Example 2-1, except that the antenna unit 10 was directly attached to the glass plate 31 without passing through the fixing portion 13A. The measurement results of the transmission loss of the TE waves are shown in FIG. 17, and the measurement results of the transmission loss of the TM waves are shown in FIG. 18.

[0151] Table 2 shows the types and thicknesses of the first to third layers in Examples 2-1 and 2-2.

[0152] [Table 2]

[0153] As is clear from FIGS. 15 to 18, in Example 2-1, the width of the transmission loss is smaller than that in Example 2-2, and the transmission loss performance is improved. Therefore, it can be said that if a space is provided between the glass plate 31 and the substrate 12 for installing the antenna, the transmission performance of electromagnetic waves can be enhanced.

[0154] [Example 3] An electromagnetic shielding layer 16 was provided on the second main surface 122 of the substrate 12 for installing the antenna, which is opposite to the glass plate 20 side, and an antenna unit 10 as shown in FIG. 6 was fabricated. This antenna unit 10 was attached to the glass plate 31 via the fixing portion 13A to fabricate a glass plate with an antenna. As the electromagnetic shielding layer 16, a glass plate with a thickness of about 6 mm and a transparent conductive film formed thereon was used, and the surface resistivity of the electromagnetic shielding layer 16 was 50 Ω / sq, 20 Ω / sq, 10 Ω / sq, 5.0 Ω / sq, and 3.0 Ω / sq. Electromagnetic waves were vertically incident on the fabricated electromagnetic shielding layer 16, and the transmission loss (TL) of the electromagnetic waves was measured. The measurement results of the transmission loss of the electromagnetic waves incident on the electromagnetic shielding layer 16 are shown in FIG. 19. As shown in FIG. 19, it was confirmed that if the surface resistivity of the electromagnetic shielding layer 16 is 10 Ω / sq or less, the transmission loss can be made about 20 dB or more.

[0155] As described above, the embodiments have been explained. However, the above embodiments are presented as examples, and the present invention is not limited by the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0156] This application claims priority based on Japanese Patent Application No. 2017-150241 filed with the Japan Patent Office on August 2, 2017, and incorporates the entire contents of Japanese Patent Application No. 2017-150241 into this application.

Explanation of Reference Numerals

[0157] 10 Antenna unit for glass (antenna unit) 11 Antenna 12 Flat substrate (substrate for installing antenna) 13A, 13B Fixing part 15 Dielectric layer 16 Electromagnetic shielding layer 20, 31 Glass plate 121, 311 First main surface 122, 312 Second main surface 21, 33 Window frame 30 Glass plate with antenna 35 Coating layer 351A, 351B Opening 36 Water-repellent treatment layer t Average thickness L Predetermined distance S Space

Claims

1. An antenna unit installed on the indoor side of a glass plate and suspended from the ceiling, comprising: an antenna; a space between the glass plate and the antenna through which air can flow; and the antenna unit for transmitting and receiving electromagnetic waves from the indoor side through the glass plate.

2. The antenna unit according to claim 1, further comprising a fixing portion for fixing the antenna to the ceiling such that a space through which air can flow is formed between the glass plate and the antenna.

3. The antenna unit according to claim 2, wherein the thickness of the fixing portion is 0.5 mm to 100 mm.

4. The fixing portion uses a spacer, and the antenna unit according to claim 2 or 3, wherein the spacer adhesively fixes the antenna to the ceiling.

5. The antenna unit according to any one of claims 1 to 4, wherein the thickness of the space is 0.5 mm to 100 mm.

6. The antenna unit according to any one of claims 1 to 5, wherein the antenna is a flat antenna or an antenna provided on a flat substrate.

7. The antenna unit according to claim 6, wherein the average solar radiation absorption rate of the main surface of the flat antenna or the flat substrate on the glass plate side is 60% or less.

8. The antenna unit according to claim 6 or 7, wherein the arithmetic mean roughness Ra of the main surface of the flat antenna or the flat substrate on the glass plate side is 1.2 μm or less.

9. The antenna unit according to any one of claims 6 to 8, further comprising a dielectric layer on the main surface of the flat antenna or the flat substrate on the glass plate side.

10. The antenna unit according to claim 9, wherein the arithmetic mean roughness Ra of the main surface of the dielectric layer on the glass plate side is 1.2 μm or less.

11. The antenna unit according to any one of claims 6 to 10, further comprising an electromagnetic shielding layer provided on the main surface of the flat antenna or the flat substrate opposite to the glass plate side.

12. The antenna unit according to any one of claims 6 to 11, further comprising one or more electromagnetic wave absorbing elements on the main surface of the flat substrate opposite to the glass plate.

13. The antenna unit according to any one of claims 1 to 12, wherein the visible light transmittance of the antenna is 40% or more.

14. The antenna unit according to any one of claims 1 to 13, wherein the antenna is an antenna provided in a housing container.

15. A method for manufacturing an antenna unit, comprising a step of attaching the antenna unit according to any one of claims 2 to 4 to the ceiling via the fixing portion so that the space is formed.

Images