WO2024079869A1

WO2024079869A1 - Light-transmissive antenna

Info

Publication number: WO2024079869A1
Application number: PCT/JP2022/038323
Authority: WO
Inventors: 央丸山; 遵阪本; 弘樹萩原
Original assignee: 日本電業工作株式会社
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2024-04-18

Abstract

This light-transmissive antenna comprises: a substrate that is formed by a light-transmissive insulating member; an antenna element part that is provided on a surface of the substrate and that is constituted from a light-transmissive electrically conductive member; a terminal, power supply terminal and cable 40 that supply power to the antenna element part; and a cover member 20 that is formed from a light-transmissive insulating member, that covers an end part of the cable 40, the power supply terminal, and the terminal, and that has projections and recesses on at least one of an inner surface and an outer surface thereof.

Description

Light-transmitting antenna

The present invention relates to a light-transmitting antenna.

There are transparent antennas that have a transparent conductive film on a transparent substrate and are configured to transmit light such as visible light. By using a transparent substrate and a transparent conductive film, transparent antennas can reduce the visibility of the antenna and prevent the appearance of the antenna from deteriorating in the location where it is installed.

Patent Document 1 discloses a film antenna having a thin film layer formed by laminating a plurality of thin films, including a thin metal film and a thin metal oxide film, on the surface of a light-transmitting substrate, the thin metal film having a portion that forms an antenna pattern and a portion that does not form the antenna pattern, and a groove that divides the thin metal film in the portion that does not form the antenna pattern.

JP 2021-57876 A

Even in a see-through antenna, the power supply section and cable that supply power to the antenna (element) are not made of optically transparent materials. For this reason, there is room for improvement in terms of reduced visibility in see-through antennas.

The purpose of the present invention is to contribute to reducing the visibility of the entire antenna by reducing the visibility of the power supply part in a light-transmitting antenna.

To achieve the above object, the present invention provides a light-transmitting antenna comprising a substrate formed of an insulating material having optical transparency, an antenna section provided on the surface of the substrate and made of an electrically conductive material having optical transparency, a power supply section for supplying power to the antenna section, and a cover member formed of an insulating material having optical transparency, covering the power supply section and having irregularities on at least one of the inner and outer surfaces.
More specifically, the covering member may have a plurality of protrusions having a triangular cross section on one of the inner surface and the outer surface.
More specifically, the protrusion of the covering member may be formed in a stripe shape in which the apexes of a triangle in cross section are connected together.
The covering member may also be configured to have a plurality of semi-spherical recesses on the other of the inner surface and the outer surface.
The covering member may also be configured to have a plurality of protrusions on its inner surface and a plurality of recesses on its outer surface.
More preferably, the convex portions and concave portions may be arranged such that the position of the lowest part between the convex portions does not coincide with the position of the deepest bottom of the concave portion.
Another aspect of the present invention that achieves the above object is a light-transmitting antenna comprising: a substrate formed of an insulating material having optical transparency; an antenna section provided on a surface of the substrate and made of an electrically conductive material having optical transparency; a power supply section that supplies power to the antenna section; and a cover section that is formed of an insulating material having optical transparency, covers the power supply section, and has an area that scatters light that passes through.

According to the present invention, by reducing the visibility of the power supply part in a light-transmitting antenna, it is possible to contribute to reducing the visibility of the entire antenna.

FIG. 1 is a diagram showing an example of installation of a light-transmitting antenna. FIG. 1 is a diagram illustrating a configuration example of a light-transmitting antenna. 1A and 1B are diagrams illustrating an example of the configuration of a light-transmitting antenna connected to a leg portion. 1A and 1B are diagrams illustrating an example of the configuration of a light-transmitting antenna provided with a covering member. 5A and 5B are diagrams showing an example of the configuration of a covering member, in which FIG. 5A is a diagram showing an outer side surface, FIG. 5B is a diagram showing an inner side surface, and FIG. 5C is a cross-sectional view taken along CC in FIG. 5B. 6A and 6B are diagrams for explaining the effect of the concealing area of the covering member, in which FIG. 6A shows how light transmits when there is no concealing area, and FIG. 6B shows how light transmits when there is a concealing area. 7A and 7B are diagrams for explaining the arrangement of the convex portions, in which FIG. 7A shows a state in which the convex portions are arranged side by side with no gaps, and FIG. 7B shows a state in which the convex portions are arranged side by side with gaps between adjacent convex portions. FIG. 4 is a diagram illustrating the positional relationship between a recess and a protrusion. FIG. 13 is a diagram showing a configuration example of a light-transmitting antenna different from that of the present embodiment.

Below, an embodiment of the present invention will be described in detail with reference to the attached drawings.

<Configuration of light-transmitting antenna>
FIG. 1 is a diagram showing an example of the installation of a light-transmitting antenna. The light-transmitting antenna 10 is installed on a ceiling or a wall surface in the premises of a house or a building. In the example shown in FIG. 1, an example in which the light-transmitting antenna 10 is installed on a ceiling 100 is shown. Hereinafter, a case in which the light-transmitting antenna 10 is installed on the ceiling 100 will be described as an example. In FIG. 1, the side of the ceiling 100 on which the light-transmitting antenna 10 is installed is called the front side of the ceiling 100. The light-transmitting antenna 10 is fixed to the ceiling 100 by legs (not shown). In the example shown, the legs are provided on the upper side of the light-transmitting antenna 10. A power line for feeding power to the light-transmitting antenna 10 is wired (not shown) on the back side of the ceiling 100, and a part of the power line is drawn into the legs. The legs have a power feed board (not shown) that connects to the terminal of the light-transmitting antenna 10. As a result, power is fed from the power line on the back of the ceiling 100 to the light-transmitting antenna 10 via the legs. The light-transmitting antenna 10 is provided with a cover member 20 that covers a part of the antenna unit.

FIG. 2 is a diagram showing an example of the configuration of the antenna section of the light-transmitting antenna 10. The light-transmitting antenna 10 includes a substrate 14, and

antenna element sections

11 and 12 and a terminal 13 provided on the surface of the substrate 14. The

antenna element sections

11 and 12 are an example of an antenna section.

The substrate 14 is a plate-like member made of an electrically insulating material that is highly transparent to visible light (light transparency). The substrate 14 may be made of any material as long as it is highly transparent and electrically insulating. For example, the substrate 14 may be made of a material such as a highly transparent resin, such as PET (Poly Ethylene Terephthalate) resin, or glass. The substrate 14 may also be flexible. In FIG. 2, the light-transmitting antenna 10 is shown upside down compared to the orientation of the light-transmitting antenna 10 shown in FIG. 1, and the legs (not shown) are attached to the underside of the light-transmitting antenna 10. Hereinafter, the side of the substrate 14 on which the legs are attached is referred to as the "installation side". The installation side is the side that comes into contact with the ceiling 100 when the substrate 14 is installed on the ceiling 100.

The

antenna element parts

11 and 12 are formed on one surface of the substrate 14 by a conductive material having optical transparency. The antenna element part 11 is, for example, a radiating element corresponding to a target frequency band, and the antenna element part 12 is, for example, an antenna GND connected to ground (GND). The

antenna element parts

11 and 12 have a shape corresponding to a target frequency band (for example, 1.7 GHz to 5 GHz). In the example shown in FIG. 2, the antenna element part 11 has a shape that gradually widens from the base part (lower part in FIG. 2) where the terminal 13 is provided to the tip part (upper part in FIG. 2). Two antenna element parts 12 are provided on both sides of the antenna element part 11 on the substrate 14. The two antenna element parts 12 extend in a direction perpendicular to the direction in which the tip of the antenna element part 11 extends. In addition, each antenna element part 12 has

protrusions

12a and 12b that protrude in a direction perpendicular to the direction in which the antenna element part 12 extends. The protrusion 12a is formed along a direction from the bottom to the top in Fig. 2, and the protrusion 12b is formed along a direction from the top to the bottom in Fig. 2, opposite to the protrusion 12a. The shapes of the

antenna element parts

11 and 12 can be appropriately determined so as to obtain the required characteristics according to the target frequency band and power resistance, and are not limited to the shape shown in Fig. 2.

The conductive members constituting the

antenna element parts

11 and 12 may be made of various materials that can be used in existing light-transmitting antennas, such as mesh-like conductors and film-like conductors. The conductive material constituting the mesh-like conductors of the

antenna element parts

11 and 12 is made of a material that has high electrical conductivity and is easy to process into a mesh shape. For example, copper (Cu), silver (Ag), aluminum (Al), etc. may be used. The film-like conductor of the

antenna element parts

11 and 12 may be made of a thin metal film with light transparency, such as Ag-stacked film.

When the light-transmitting antenna 10 is attached to the leg, the terminal 13 is connected to the power supply board of the leg and supplies power to the

antenna element parts

11 and 12. The terminals 13 consist of a terminal 13 provided at the base of the antenna element part 11 and a terminal 13 provided on each of the two antenna element parts 12. These terminals 13 are power supply parts that supply power to the

antenna element parts

11 and 12. In the light-transmitting antenna 10 shown in Figure 2, a protrusion 12b is formed on the antenna element part 12, so that the terminal 13 is provided at a position separated from the end of the board 14 on the leg side (the bottom end of the board 14 in Figure 2).

FIG. 3 is a diagram showing an example of the configuration of an optically transparent antenna 10 connected to a leg. The leg 30 shown in FIG. 3 comprises a power supply board 31 and a leg body 32. In FIG. 3, the illustration of the cover member 20 is omitted in order to show how the power supply board 31 of the leg 30 is connected to the optically transparent antenna 10.

The power supply board 31 is a plate-like member made of an electrically insulating material with high optical transparency. The power supply board 31 may be made of, for example, the same material as the board 14 of the light-transmitting antenna 10. The power supply board 31 is attached to the surface of the board 14 of the light-transmitting antenna 10 on the side on which the

antenna element sections

11 and 12 are formed. The power supply board 31 is provided with a plurality of power supply terminals 31a corresponding to the plurality of terminals 13 of the light-transmitting antenna 10. When the power supply board 31 is attached to the board 14 of the light-transmitting antenna 10, the power supply terminals 31a are connected to the terminals 13 of the

antenna element sections

11 and 12, and power is supplied from the power supply terminals 31a via the terminals 13 to the

antenna element sections

11 and 12.

The leg body 32 is attached to the installation side of the substrate 14 of the light-transmitting antenna 10. The leg body 32 is a tubular member, and the cable 40 connected to the power supply terminal 31a passes through an internal through hole. In the example shown in FIG. 3, the power supply substrate 31 is provided on the upper end side of the leg body 32, and the cable 40 connected to the power supply terminal 31a of the power supply substrate 31 passes through a through hole inside the leg body 32 (not shown) and is drawn out from the lower end side of the leg body 32. Although not shown, the cable 40 exposed from the leg body 32 is connected to a power line wired on the back side of the ceiling 100. The leg body 32 is made of, for example, resin or metal. The leg body 32 is embedded in the ceiling 100 on which the light-transmitting antenna 10 is installed, and the light-transmitting antenna 10 attached to the leg body 32 is fixed to the ceiling 100.

As described above, the power supply board 31 is optically transparent, but the power supply terminal 31a and the cable 40 are not optically transparent. Therefore, when the power supply board 31 is attached to the light-transmitting antenna 10, the power supply board 31 itself is poorly visible, but the power supply terminal 31a and the cable 40 are highly visible. Therefore, by providing a cover member 20 on the light-transmitting antenna 10, the visibility of the power supply terminal 31a and the cable 40 is reduced. The power supply terminal 31a, the cable 40, and the terminal 13 of the light-transmitting antenna 10 are an example of a power supply section.

9 is a diagram showing an example of the configuration of a light-transmitting antenna different from this embodiment. The light-transmitting antenna 110 shown in FIG. 9 includes a substrate 114 and

antenna element parts

111 and 112. The substrate 114 and the

antenna element parts

111 and 112 correspond to the substrate 14 and the

antenna element parts

11 and 12 of the light-transmitting antenna 10 described with reference to FIG. 2. The light-transmitting antenna 110 is attached to the front side of the ceiling 100 and connected to the power line via the legs 130. As mentioned above, the shape of the antenna element part of the light-transmitting antenna is determined according to the target frequency band and power resistance, but the shape of the

antenna element parts

111 and 112 of the light-transmitting antenna 110 shown in FIG. 9 is different from the shape of the

antenna element parts

11 and 12 of this embodiment. In particular, the antenna element part 112 does not have a protruding part corresponding to the protruding part 12b in the antenna element part 12 of this embodiment. For this reason, in the light-transmitting antenna 110 shown in FIG. 9, the terminals (not shown) of the

antenna element parts

111 and 112 are provided at positions closer to the leg 130 side of the substrate 114 than the terminal 13 of the light-transmitting antenna 10 of this embodiment. In this configuration, the power supply terminal and cable for connecting to the terminals of the

antenna element parts

111 and 112 to supply power are located at the end of the substrate 114 on the leg 130 side (the lower end of the substrate 114 in FIG. 9), and therefore visibility is poor. In contrast, in the light-transmitting antenna 10 of this embodiment, the terminal 13 is located away from the end of the substrate 14 on the leg side (the lower end of the substrate 14 in FIG. 2) as described above, so a cover member 20 is provided to reduce the visibility of the power supply terminal 31a and the cable 40.

FIG. 4 is a diagram showing an example of the configuration of the light-transmitting antenna 10 provided with a covering member 20. FIG. 4 shows the light-transmitting antenna 10 in the state shown in FIG. 3 with a covering member 20 provided.

The covering member 20 is a plate-like member made of an electrically insulating material with high optical transparency, and is provided on the installation side of the substrate 14 of the optically transparent antenna 10. For example, the covering member 20 may be made of the same material as the substrate 14 of the optically transparent antenna 10. The covering member 20 is provided on both sides of the substrate 14 (the surface on which the

antenna element portions

11 and 12 are formed and the opposite surface). The covering member 20 is curved so that the center is higher than the edges of the substrate 14 excluding the installation side. This provides a space between the covering member 20 and the terminals 13 and the power supply board 31 provided on the substrate 14. The edges of the covering member 20 on the installation side of the substrate 14 may be in contact with the substrate 14 or may be separated from the substrate 14.

A concealing area 21 is formed near the center of the covering member 20. Specifically, the concealing area 21 is formed in a position that covers the power supply board 31 of the leg 30 and the cable 40 connected to the power supply board 31 when the covering member 20 is attached to the substrate 14. The concealing area 21 is configured to scatter visible light that passes through it. As an example of a means for scattering visible light, the concealing area 21 has unevenness formed on the inner surface located on the inside and the outer surface located on the outside when the covering member 20 is attached to the substrate 14.

<Configuration of Covering Member>
5 is a diagram showing an example of the configuration of the covering member 20. FIG. 5(A) is a diagram showing the outer side, FIG. 5(B) is a diagram showing the inner side, and FIG. 5(C) is a cross-sectional view taken along the line C-C of FIG. 5(B). However, FIG. 5(C) shows an enlarged view of a part of the cross section. As shown in FIGS. 5(A) and 5(B), the covering member 20 has a leg cover 23 provided on the edge of the installation side (the lower side of the figure). The leg cover 23 covers the end of the leg 30 on the light-transmitting antenna 10 side when the covering member 20 is attached to the substrate 14 of the light-transmitting antenna 10. As a result, the light-transmitting antenna 10 to which the covering member 20 is attached is fixed to the leg 30.

A plurality of recesses 21b are formed on the outer surface of the concealing area 21 of the covering member 20. Each recess 21b is a hemispherical depression. Therefore, the surface forming each recess 21b forms a spherical surface. In the example shown in FIG. 5(A), a plurality of recesses 21b are arranged vertically and horizontally within the concealing area 21.

In the example shown in FIG. 5(A), a streak-like uneven portion 22 is provided on the lower side of the concealing area 21 along the edge of the installation side of the covering member 20. The streak-like uneven portion 22 is configured by arranging multiple streak-like uneven portions in parallel. In the example shown, streak-like uneven portions are formed that extend in a direction perpendicular to the edge of the installation side of the covering member 20 (the vertical direction in the figure). The streak-like uneven portion 22 provided on the lower side of the concealing area 21 reduces the visibility of the protrusion 24, which will be described later.

A number of protrusions 21a are formed on the inner surface of the concealing area 21 of the covering member 20. Each protrusion 21a has a triangular cross section and is formed in a stripe shape with the vertices of the triangle connected together. In the example shown in FIG. 5(B), the stripes of the protrusions 21a are made up of parallel straight lines. As shown in FIGS. 5(A) and (B), the protrusions 21a on the inner surface and the recesses 21b on the outer surface are arranged in corresponding areas.

In the example shown in Figures 5(B) and (C), a positioning protrusion 24 is provided below the concealed area 21. When attaching the cover member 20 to the substrate 14 of the optically transparent antenna 10, the protrusion 24 is inserted into a hole (not shown) provided in the substrate 14, thereby positioning the cover member 20 relative to the substrate 14.

FIG. 6 is a diagram explaining the effect of the concealing region 21 of the covering member 20. FIG. 6(A) is a diagram showing how light passes when there is no concealing region 21, and FIG. 6(B) is a diagram showing how light passes when there is a concealing region 21. FIGS. 6(A) and (B) show the positional relationship between the substrate 14 of the optically transparent antenna 10, the power supply substrate 31 of the leg 30, and the covering member 20. For simplicity, the outer and inner surfaces of the covering member 20 in FIG. 6(A) are assumed to be parallel. Also, FIG. 6(B) shows only the simplified protrusion 21a of the concealing region 21.

If there is no concealed area 21, the light passing through the covering member 20 is refracted when it enters and exits the covering member 20, but the direction of travel of the light before it enters and after it exits is approximately the same. Therefore, as shown in FIG. 6(A), when looking toward the power supply board 31 from the observation position OP, the light from the power supply board 31 is observed, and the power supply terminal 31a and cable 40 provided on the power supply board 31 are visible.

On the other hand, when there is a concealed area 21, the light passing through the covering member 20 is scattered, and the light travels in different directions before entering and after exiting the covering member 20. For this reason, as shown in FIG. 6(B), when looking toward the power supply board 31 from the observation position OP, light is observed from various directions, making it difficult to see the power supply terminal 31a and cable 40 provided on the power supply board 31.

Here, we will further explain the convex portions 21a and concave portions 21b formed in the concealing region 21 of the covering member 20. As explained with reference to Figure 5, the convex portions 21a formed on the inner surface of the covering member 20 have a triangular cross section and form stripe-like irregularities. Furthermore, the concave portions 21b formed on the outer surface of the covering member 20 form a collection of hemispherical depressions. The way in which light passing through the covering member 20 is scattered varies depending on the arrangement of the convex portions 21a and concave portions 21b.

FIG. 7 is a diagram explaining the arrangement of the convex portions 21a. FIG. 7(A) is a diagram showing the convex portions 21a arranged side by side with no gaps, and FIG. 7(B) is a diagram showing the convex portions 21a arranged side by side with gaps between adjacent convex portions 21a. For simplicity, the outer surface of the covering member 20 is assumed to be flat, and the function of the convex portions 21a when no concave portions 21b are provided will be explained.

Because the cross section of the convex portion 21a is triangular, the surface of the convex portion 21a is inclined with respect to the outer surface of the covering member 20. For this reason, as shown in FIG. 7(A), light that is incident on the covering member 20 from the convex portion 21a side is refracted and reflected in various ways by the inclined surface of the convex portion 21a and the outer surface of the covering member 20 that is not parallel to this inclined surface. Then, the light is emitted in a direction different from the direction of incidence on the covering member 20.

Now, let us consider a method for manufacturing the covering member 20. The covering member 20 is manufactured by molding using a metal mold. In this case, the shape of the convex portions 21a is determined by the metal mold. When the convex portions 21a, each having a triangular cross section, are arranged without any gaps as shown in FIG. 7(A), it is necessary to use a metal mold with a sharp pointed shape in order to form depressions between adjacent convex portions 21a. However, since a metal mold with a pointed shape has a limited strength, in reality, it is expected that the covering member 20 will be molded using a metal mold with a blunt tip.

When the protrusions 21a of the covering member 20 are molded using a mold with a blunt tip, as shown in FIG. 7(B), a gap is created at the lowest point between adjacent protrusions 21a, resulting in a surface 21c that is approximately parallel to the outer surface of the covering member 20. Of the light that is incident on the covering member 20 from the protrusion 21a side, the light that is incident from surface 21c is partially reflected by the inner surface of the covering member 20, but exits from the outer surface of the covering member 20 in an exit direction that generally coincides with the direction of incidence. For this reason, at the position of surface 21c, the power supply terminal 31a and cable 40 covered by the covering member 20 can be seen. As a means to solve this, a recess 21b is provided on the outer surface of the covering member 20.

Figure 8 is a diagram explaining the positional relationship between the recess 21b and the protrusion 21a. Since the recess 21b is a hemispherical depression, the entire surface is curved. Therefore, the angle of each part of the recess 21b with respect to the outer surface of the covering member 20 is different. This makes the scattering of light that passes through the covering member 20 and exits complex. However, since the recess 21b is hemispherical, the deepest bottom is approximately parallel to the surface 21c of the gap between the protrusions 21a. Therefore, when the position of the bottom of the recess 21b and the position of the surface 21c are aligned, the light that enters from the surface 21c exits from the bottom of the recess 21b in an exit direction that is approximately the same as the direction of incidence. Then, at the position where the bottom of the recess 21b and the surface 21c overlap, the power supply terminal 31a and the cable 40 covered by the covering member 20 can be seen. To solve this problem, each protrusion 21a and recess 21b is positioned so that the position of the bottom of recess 21b does not coincide with the position of surface 21c.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned embodiment, the convex portion 21a provided in the concealing region 21 of the covering member 20 is a streak-like convex portion with a series of triangular vertices, but a configuration in which multiple protrusions having individual vertices are arranged vertically and horizontally may be used. In addition, in the above-mentioned embodiment, the concave portion 21b is a hemispherical depression, but it may be a depression formed by a part of a sphere or other curved surface. Furthermore, in the above-mentioned embodiment, the convex portion 21a is provided on the inner surface of the covering member 20 and the concave portion 21b is provided on the outer surface, but it may be a configuration in which a concave portion is provided on the inner surface and a convex portion is provided on the outer surface, or a configuration in which a concave portion or a convex portion is provided on both the inner surface and the outer surface. Furthermore, it may be a configuration in which a convex portion or a concave portion is provided on either the inner surface or the outer surface. In addition, it may be a configuration in which a convex portion or a concave portion is provided on either the inner surface or the outer surface. In addition, various modifications and alternative configurations that do not deviate from the scope of the technical idea of the present invention are included in the present invention.

10...light-transmitting antenna, 11, 12...antenna element portion, 12a, 12b...protruding portion, 13...terminal, 14...substrate, 20...covering member, 21...hidden area, 30...leg portion, 31...power supply substrate, 31a...power supply terminal, 40...cable, 100...ceiling

Claims

A substrate formed of an insulating material having optical transparency;
an antenna portion provided on a surface of the substrate and made of a conductive material having optical transparency;
A power supply unit that supplies power to the antenna unit;
a cover member formed of an insulating material having optical transparency, covering the power supply unit, and having projections and recesses on at least one of an inner surface and an outer surface;
A light-transmitting antenna comprising:
The optically transparent antenna according to claim 1, characterized in that the covering member has multiple protrusions with triangular cross sections on one of the inner surface and the outer surface.
The optically transparent antenna according to claim 2, characterized in that the convex portion of the covering member is formed in a stripe shape with the vertices of a triangle in cross section connected together.
The optically transparent antenna according to claim 2 or 3, characterized in that the covering member has a plurality of hemispherical recesses on the other of the inner surface and the outer surface.
The optically transparent antenna according to claim 4, characterized in that the convex portions and the concave portions are arranged such that the position of the lowest part between the convex portions does not coincide with the position of the deepest bottom of the concave portion.
The optically transparent antenna according to claim 1, characterized in that the cover member has a plurality of convex portions on the inner surface and a plurality of concave portions on the outer surface.
The optically transparent antenna according to claim 6, characterized in that the convex portions and the concave portions are arranged such that the position of the lowest part between the convex portions does not coincide with the position of the deepest bottom of the concave portion.
A substrate formed of an insulating material having optical transparency;
an antenna portion provided on a surface of the substrate and made of a conductive material having optical transparency;
A power supply unit that supplies power to the antenna unit;
a cover portion formed of an insulating material having optical transparency, covering the power supply portion and having a region for scattering light passing through the cover portion;
A light-transmitting antenna comprising: