Light-transmissive antenna

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

Technical Field

[0001] The present invention relates to a light-transmissive antenna.

Background Art

[0002] There is a transmissive antenna configured to transmit light such as visible light by providing a transparent conductive film on a transparent substrate. The transmissive antenna can suppress the visibility of the antenna by using a transparent substrate and a transparent conductive film, and can suppress the deterioration of the appearance at the installation location of the antenna.

[0003] Patent Document 1 discloses a film antenna having a thin film layer in which a plurality of thin films including a metal thin film and a metal oxide thin film are laminated on the surface of a light-transmissive substrate, the metal thin film having a portion constituting an antenna pattern and a portion not constituting an antenna pattern, and the portion not constituting the antenna pattern having a groove portion for dividing the metal thin film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Even in a transmissive antenna, the power supply portion and the cable for supplying power to the antenna (element) are not made of light-transmissive members. For this reason, there has been room for improvement regarding the reduction of visibility in the transmissive antenna.

[0006] An object of the present invention is to contribute to the reduction of the visibility of the entire antenna by reducing the visibility of the power supply portion in a light-transmissive antenna.

Means for Solving the Problems

[0007] The present invention for achieving the above object is a light transmissive antenna comprising: a substrate formed of an insulating member having light transmissivity; an antenna portion provided on the surface of the substrate and composed of a conductive member having light transmissivity; a power feeding portion for supplying power to the antenna portion; and a covering member formed of an insulating member having light transmissivity, covering the power feeding portion, and having irregularities on at least one of an inner surface and an outer surface. More specifically, the covering member may be configured to have a plurality of convex portions having a triangular cross section on one of the inner surface and the outer surface. Even more specifically, the convex portions of the covering member may be formed in a streaky shape in which the vertices of the triangular cross sections are continuous. Also, the covering member may be configured to have a plurality of hemispherical concave portions on the other of the inner surface and the outer surface. Also, the covering member may be configured to have a plurality of convex portions on the inner surface and a plurality of concave portions on the outer surface. More preferably, the convex portions and the 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 part of the concave portion. Another present invention for achieving the above object is a light transmissive antenna comprising: a substrate formed of an insulating member having light transmissivity; an antenna portion provided on the surface of the substrate and composed of a conductive member having light transmissivity; a power feeding portion for supplying power to the antenna portion; and a covering portion formed of an insulating member having light transmissivity, covering the power feeding portion, and having a region for scattering transmitted light.

Effects of the Invention

[0008] According to the present invention, in a light transmissive antenna, by reducing the visibility of the power feeding portion, it is possible to contribute to the reduction of the visibility of the entire antenna.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 8

Figure 9

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Configuration of Light Transmissive Antenna> FIG. 1 is a diagram showing an installation example of a light-transmissive antenna. The light-transmissive antenna 10 is installed on the ceiling, wall surface, etc. inside a house or building. In the example shown in FIG. 1, an example where the light-transmissive antenna 10 is installed on the ceiling 100 is shown. Hereinafter, the case where the light-transmissive antenna 10 is installed on the ceiling 100 will be described as an example. In FIG. 1, the side of the ceiling 100 where the light-transmissive antenna 10 is installed is called the front side of the ceiling 100. The light-transmissive antenna 10 is fixed to the ceiling 100 by legs (not shown). In the illustrated example, the legs are provided on the upper side of the light-transmissive antenna 10. On the back side of the ceiling 100, a power line for supplying power to the light-transmissive antenna 10 is wired (not shown), and a part of it is drawn into the legs. The legs have a power supply board (not shown) connected to the terminals of the light-transmissive antenna 10. Thereby, power is supplied from the power line on the back of the ceiling 100 to the light-transmissive antenna 10 through the legs. A covering member 20 that covers a part of the antenna portion is provided on the light-transmissive antenna 10.

[0012] FIG. 2 is a diagram showing a configuration example of the antenna portion of the light-transmissive antenna 10. The light-transmissive antenna 10 includes a substrate 14, and antenna element portions 11, 12 and terminals 13 provided on the surface of the substrate 14. The antenna element portions 11, 12 are an example of the antenna portion.

[0013] The substrate 14 is a plate-like member made of an electrically insulating material having high visible light transmittance (light transmittance). The substrate 14 only needs to have high light transmittance and electrical insulation, and the type of material does not matter. For example, the substrate 14 can be formed using a resin with high light transmittance such as PET (Poly Ethylene Terephthalate) resin or a material such as glass. Further, the substrate 14 may have flexibility (softness). In FIG. 2, the up and down directions are shown opposite to the orientation of the light-transmissive antenna 10 shown in FIG. 1, and the legs (not shown) are attached to the lower side of the light-transmissive antenna 10. Hereinafter, the side of the substrate 14 to which the legs are attached will be called the "installation side". The installation side is the side that contacts the ceiling 100 when the substrate 14 is installed on the ceiling 100.

[0014] The antenna element parts 11 and 12 are formed on the surface on one side of the substrate 14 by a conductive member having light transmissibility. 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 the 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 expands from the base part (lower part in FIG. 2) provided with the terminal 13 toward 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 orthogonal to the direction in which the tip of the antenna element part 11 extends. Further, on each antenna element part 12, protruding parts 12a and 12b that protrude in a direction orthogonal to the direction in which the antenna element part 12 extends are formed. The protruding part 12a is formed along the direction from the lower part to the upper part in FIG. 2, and the protruding part 12b is formed along the direction from the upper part to the lower part in FIG. 2, opposite to the protruding part 12a. Note that the shapes of the antenna element parts 11 and 12 may be appropriately determined so that the required characteristics can be obtained according to the target frequency band and the withstand power, and are not limited to the shapes shown in FIG. 2.

[0015] As the conductive member constituting the antenna element parts 11 and 12, various materials that can be used for existing light transmissive antennas, such as a mesh-like conductor or a film-like conductor, can be used. As the conductor material constituting the mesh-like conductor of the antenna element parts 11 and 12, a material having high electrical conductivity and being easily processed into a mesh shape is used. For example, copper (Cu), silver (Ag), aluminum (Al), etc. can be used. As the film-like conductor of the antenna element parts 11 and 12, for example, a metal thin film having light transmissibility such as an Ag stacked film (Ag-Stacked Film) can be used.

[0016] Terminal 13 is connected to the power supply substrate of the leg portion in a state where the light transmissive antenna 10 is attached to the leg portion, and supplies power to the antenna element portions 11 and 12. Terminal 13 is composed of a terminal 13 provided at the root portion of the antenna element portion 11 and terminals 13 provided at each of the two antenna element portions 12. These terminals 13 are a power supply unit that supplies power to the antenna element portions 11 and 12. In the light transmissive antenna 10 shown in FIG. 2, since the protruding portion 12b is formed in the antenna element portion 12, the terminal 13 is provided at a position separated from the end portion on the leg side of the substrate 14 (the lower end of the substrate 14 in FIG. 2).

[0017] FIG. 3 is a diagram showing a configuration example of the light transmissive antenna 10 connected to the leg portion. The leg portion 30 shown in FIG. 3 includes a power supply substrate 31 and a leg body 32. In FIG. 3, in order to show the state where the power supply substrate 31 of the leg portion 30 is connected to the light transmissive antenna 10, the description of the covering member 20 is omitted.

[0018] The power supply substrate 31 is a plate-like member made of an electrically insulating material with high light transmissivity. As the power supply substrate 31, for example, it may be formed of the same material as the substrate 14 of the light transmissive antenna 10. The power supply substrate 31 is used by being attached to the surface of the substrate 14 of the light transmissive antenna 10 on the side where the antenna element portions 11 and 12 are formed. The power supply substrate 31 is provided with a plurality of power supply terminals 31a corresponding to the plurality of terminals 13 of the light transmissive antenna 10. In a state where the power supply substrate 31 is attached to the substrate 14 of the light transmissive antenna 10, the power supply terminals 31a are connected to the terminals 13 of the respective antenna element portions 11 and 12, and power is supplied from the power supply terminals 31a to the antenna element portions 11 and 12 via the terminals 13.

[0019] The foot body 32 is attached to the installation side of the substrate 14 of the light transmissive antenna 10. The foot body 32 is a cylindrical member, and a cable 40 connected to the power supply terminal 31a passes through the internal through hole. In the example shown in FIG. 3, a power supply substrate 31 is provided on the upper end side of the foot body 32, and the cable 40 connected to the power supply terminal 31a of the power supply substrate 31 passes through the through hole inside the foot body 32 (not shown) and is drawn out from the lower end side of the foot body 32. Although not particularly shown, the cable 40 exposed from the foot body 32 is connected to a power line wired on the back side of the ceiling 100. The foot body 32 is made of, for example, resin or metal. By embedding the foot body 32 in the ceiling 100 where the light transmissive antenna 10 is installed, the light transmissive antenna 10 attached to the foot body 32 is fixed to the ceiling 100.

[0020] As described above, the power supply substrate 31 has light transmissivity, but the power supply terminal 31a and the cable 40 do not have light transmissivity. Therefore, when the power supply substrate 31 is attached to the light transmissive antenna 10, the visibility of the power supply substrate 31 itself is low, but the visibility of the power supply terminal 31a and the cable 40 is high. Thus, by providing a covering member 20 on the light transmissive 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 transmissive antenna 10 are an example of a power supply unit.

[0021] FIG. 9 is a diagram showing a configuration example of a light transmissive antenna different from the present embodiment. The light transmissive antenna 110 shown in FIG. 9 includes a substrate 114 and antenna element portions 111 and 112. The substrate 114 and the antenna element portions 111 and 112 correspond to the substrate 14 and the antenna element portions 11 and 12 of the light transmissive antenna 10 described with reference to FIG. 2. The light transmissive antenna 110 is attached to the front side of the ceiling 100 and is connected to a power line via a leg portion 130. Although it has been described that the shape of the antenna element portion of the light transmissive antenna is determined according to the target frequency band and the withstand power, the shapes of the antenna element portions 111 and 112 of the light transmissive antenna 110 shown in FIG. 9 are different from the shapes of the antenna element portions 11 and 12 of the present embodiment. In particular, the antenna element portion 112 does not have a protruding portion corresponding to the protruding portion 12b in the antenna element portion 12 of the present embodiment. For this reason, in the light transmissive antenna 110 shown in FIG. 9, the terminals (not shown) of each of the antenna element portions 111 and 112 are provided at positions closer to the side on the leg portion 130 side of the substrate 114 as compared with the terminals 13 of the light transmissive antenna 10 of the present embodiment. In such a configuration, since the power supply terminals and the cables for connecting and powering the terminals of each of the antenna element portions 111 and 112 are located at the end portion on the leg portion 130 side of the substrate 114 (the lower end of the substrate 114 in FIG. 9), the visibility is poor. On the other hand, in the light transmissive antenna 10 of the present embodiment, since the terminal 13 is located at a position separated from the end portion on the leg portion side of the substrate 14 (the lower end of the substrate 14 in FIG. 2) as described above, a covering member 20 for reducing the visibility of the power supply terminal 31a and the cable 40 is provided.

[0022] FIG. 4 is a diagram showing a configuration example of the light transmissive antenna 10 provided with the covering member 20. FIG. 4 shows a state in which the covering member 20 is provided on the light transmissive antenna 10 in the state shown in FIG. 3.

[0023] The covering member 20 is a plate-shaped member made of an electrically insulating material with high light transmittance, and is provided on the installation side of the substrate 14 of the light transmissive antenna 10. As the covering member 20, for example, it may be formed of the same material as the substrate 14 of the light transmissive antenna 10. The covering member 20 is provided on both sides of the substrate 14 (the surface on which the antenna elements 11 and 12 are formed and the opposite surface). The covering member 20 is formed to be curved so that the center is higher than the edge portion excluding the installation side of the substrate 14. Thereby, a space is provided between the terminal 13 and the power supply substrate 31 provided on the substrate 14 and the covering member 20. Among the edge portions of the covering member 20, the edge portion on the installation side of the substrate 14 may be in contact with the substrate 14 or may be separated from the substrate 14.

[0024] A light shielding region 21 is formed near the center of the covering member 20. Specifically, the light shielding region 21 is formed at a position that covers the power supply substrate 31 of the leg portion 30 and the cable 40 connected to the power supply substrate 31 in a state where the covering member 20 is attached to the substrate 14. The light shielding region 21 is configured to scatter transmitted visible light. As an example of means for scattering visible light, unevenness is formed on the inner surface located inside and the outer surface located outside in a state where the covering member 20 is attached to the substrate 14 in the light shielding region 21.

[0025] <Configuration of the covering member> FIG. 5 is a diagram showing a configuration example of the covering member 20. FIG. 5(A) is a diagram showing the outer surface, FIG. 5(B) is a diagram showing the inner surface, and FIG. 5(C) is a cross-sectional view taken along the line C-C of FIG. 5(B). However, FIG. 5(C) shows a partially enlarged cross section. As shown in FIGS. 5(A) and 5(B), the covering member 20 is provided with a leg cover 23 at the edge portion on the installation side (the lower side in the figure). The leg cover 23 covers the end portion on the light transmissive antenna 10 side of the leg portion 30 in a state where the covering member 20 is attached to the substrate 14 of the light transmissive antenna 10. Thereby, the light transmissive antenna 10 to which the covering member 20 is attached is fixed to the leg portion 30.

[0026] On the outer surface of the light-shielding region 21 of the covering member 20, a plurality of recesses 21b are formed. Each individual recess 21b is a hemispherical depression. Therefore, the surface forming each recess 21b constitutes a spherical surface. In the example shown in FIG. 5(A), a plurality of recesses 21b are arranged side by side vertically and horizontally within the light-shielding region 21.

[0027] Also, in the example shown in FIG. 5(A), on the lower side of the light-shielding region 21, along the edge on the installation side of the covering member 20, a ribbed uneven portion 22 is provided. The ribbed uneven portion 22 is configured by arranging a plurality of rib-shaped unevenness in parallel. In the illustrated example, rib-shaped unevenness extending in a direction perpendicular to the edge on the installation side of the covering member 20 (the vertical direction in the figure) is formed. The ribbed uneven portion 22 provided at the lower part of the light-shielding region 21 reduces the visibility of the protruding portion 24 described later.

[0028] On the inner surface of the light-shielding region 21 of the covering member 20, a plurality of convex portions 21a are formed. Each individual convex portion 21a has a triangular cross-section and is formed in a rib shape where the vertices of the triangles are connected. In the example shown in FIG. 5(B), the ribs of the convex portions 21a are composed of parallel straight lines. As shown in FIGS. 5(A) and (B), the convex portions 21a on the inner surface and the recesses 21b on the outer surface are arranged within corresponding regions.

[0029] Also, in the examples shown in FIGS. 5(B) and (C), on the lower side of the light-shielding region 21, a positioning protruding portion 24 is provided. When attaching the covering member 20 to the substrate 14 of the light-transmissive antenna 10, the covering member 20 is positioned with respect to the substrate 14 by inserting the protruding portion 24 into a hole (not shown) provided in the substrate 14.

[0030] FIG. 6 is a diagram for explaining the action of the light-shielding region 21 of the covering member 20. FIG. 6(A) is a diagram showing the state of light transmission when there is no light-shielding region 21, and FIG. 6(B) is a diagram showing the state of light transmission when there is a light-shielding region 21. In FIGS. 6(A) and 6(B), the positional relationship among the substrate 14 of the light-transmissive antenna 10, the power supply substrate 31 of the leg portion 30, and the covering member 20 is shown. Here, for simplicity, it is assumed that the outer surface and the inner surface of the covering member 20 are parallel in FIG. 6(A). Further, in FIG. 6(B), only the convex portion 21a simplified with respect to the light-shielding region 21 is shown.

[0031] When there is no light-shielding region 21, the light transmitted through the covering member 20 is refracted when entering and exiting the covering member 20, but the traveling directions of the light before incidence and after emission are substantially the same. Therefore, as shown in FIG. 6(A), when looking at the direction of the power supply substrate 31 from the observation position OP, the light from the power supply substrate 31 is observed, and the power supply terminal 31a and the cable 40 provided on the power supply substrate 31 can be seen.

[0032] On the other hand, when there is a light-shielding region 21, the light transmitted through the covering member 20 is scattered, and the traveling directions of the light before entering and after exiting the covering member 20 are various. Therefore, as shown in FIG. 6(B), when looking at the direction of the power supply substrate 31 from the observation position OP, the light from various directions is observed, and the power supply terminal 31a and the cable 40 provided on the power supply substrate 31 are difficult to see.

[0033] Here, the convex portion 21a and the concave portion 21b formed in the light-shielding region 21 of the covering member 20 will be further described. As described with reference to FIG. 5, the convex portion 21a formed on the inner surface of the covering member 20 has a triangular cross section and constitutes streak-shaped irregularities. Further, the concave portion 21b formed on the outer surface of the covering member 20 constitutes a collection of hemispherical depressions. The light transmitted through the covering member 20 is scattered in different ways according to the arrangement of the convex portion 21a and the concave portion 21b.

[0034] FIG. 7 is a diagram for explaining the arrangement of the convex portions 21a. FIG. 7(A) is a diagram showing a state in which the convex portions 21a are arranged side by side without gaps, and FIG. 7(B) is a diagram showing a state in which the convex portions 21a are arranged side by side with gaps between adjacent convex portions 21a. Here, for simplicity, it is assumed that the outer surface of the covering member 20 is a plane, and the operation of the convex portion 21a in the case where the concave portion 21b is not provided will be described.

[0035] Since 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, the light incident from the convex portion 21a side with respect to the covering member 20 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, as shown in FIG. 7(A). Then, it is emitted in a direction different from the incident direction with respect to the covering member 20.

[0036] Here, consider the manufacturing method of the covering member 20. It is assumed that the covering member 20 is manufactured by molding using a mold. In this case, the shape of the convex portion 21a is determined by the mold. When arranging the convex portions 21a having a triangular cross section side by side without gaps as shown in FIG. 7(A), it is necessary to use a mold having a sharply pointed shape in order to form a depression between adjacent convex portions 21a. However, since a mold with a pointed shape has a strength limit, in reality, it is assumed that the covering member 20 is molded using a mold whose tip is not pointed.

[0037] When the convex portion 21a of the covering member 20 is molded by a mold whose tip is not pointed, as shown in FIG. 7(B), a gap is formed in the lowest portion between adjacent convex portions 21a, and a surface 21c substantially parallel to the outer surface of the covering member 20 is generated. Among the light incident from the convex portion 21a side with respect to the covering member 20, the light incident from the surface 21c is mostly reflected by the inner surface of the covering member 20, but is emitted from the outer surface of the covering member 20 in an emission direction that generally coincides with the incident direction. For this reason, at the position of the surface 21c, the power supply terminal 31a and the cable 40 covered by the covering member 20 can be visually recognized. As a means for eliminating this, a concave portion 21b is provided on the outer surface of the covering member 20.

[0038] FIG. 8 is a diagram for explaining the positional relationship between the concave portion 21b and the convex portion 21a. Since the concave portion 21b is a hemispherical depression, the entire surface is a curved surface. For this reason, the angle with respect to the outer surface of the covering member 20 is different for each part of the concave portion 21b. As a result, the scattering of the light transmitted through the covering member 20 becomes complicated. However, since the concave portion 21b is hemispherical, the deepest bottom portion is substantially parallel to the surface 21c of the gap of the convex portion 21a. Therefore, when the position of the bottom portion of the concave portion 21b coincides with the position of the surface 21c, the light incident from the surface 21c is emitted from the bottom portion of the concave portion 21b in an emission direction that generally coincides with the incident direction. And at the position where the bottom of the concave portion 21b and the surface 21c overlap, the power supply terminal 31a and the cable 40 covered by the covering member 20 can be visually recognized. As a means for eliminating this, the individual convex portions 21a and concave portions 21b are arranged so that the position of the bottom portion of the concave portion 21b and the position of the surface 21c do not coincide.

[0039] As described above, the embodiments of the present invention have been described, but the technical scope of the present invention is not limited to the above embodiments. For example, in the above embodiment, the convex portion 21a provided in the light shielding region 21 of the covering member 20 is a streak-shaped convex portion in which the vertices of the triangles are connected, but a configuration in which a plurality of protrusions having individual vertices are arranged side by side vertically and horizontally may be used. Further, in the above embodiment, the concave portion 21b is a hemispherical depression, but it may be a depression formed by a part of a spherical surface or other curved surfaces. Furthermore, in the above 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 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 concave portions or convex portions are provided on both the inner surface and the outer surface may be used. Furthermore, a configuration in which a convex portion or a concave portion is provided on either the inner surface or the outer surface may be used. In addition, various changes and configuration alternatives that do not depart from the scope of the technical idea of the present invention are included in the present invention.

Description of Reference Numerals

[0040] 10... Light transmissive antenna, 11, 12... Antenna element parts, 12a, 12b... Protrusions, 13... Terminal, 14... Substrate, 20... Covering member, 21... Light shielding region, 30... Leg portion, 31... Power supply substrate, 31a... Power supply terminal, 40... Cable, 100... Ceiling

Claims

1. a substrate formed of an insulating member having light transmissivity; an antenna portion provided on the surface of the substrate and composed of a conductive member having light transmissivity; a power feeding portion for supplying power to the antenna portion; a covering member formed of an insulating member having light transmissivity, covering the power feeding portion, and having irregularities on at least one of an inner surface and an outer surface; A light transmissive antenna, comprising:

2. The light transmissive antenna according to claim 1, wherein the covering member has a plurality of convex portions having a triangular cross section on one of the inner surface and the outer surface.

3. The light transmissive antenna according to claim 2, wherein the convex portions of the covering member are formed in a streak shape in which the vertices of the triangles of the cross sections are continuous.

4. The light transmissive antenna according to claim 2 or claim 3, wherein the covering member has a plurality of hemispherical concave portions on the other of the inner surface and the outer surface.

5. The light transmissive antenna according to claim 4, wherein the convex portions and the concave portions are arranged such that a position of a lowest portion between the convex portions does not coincide with a position of a deepest bottom portion of the concave portions.

6. The light transmissive antenna according to claim 1, wherein the covering member has a plurality of convex portions on the inner surface and a plurality of concave portions on the outer surface.

7. The light transmissive antenna according to claim 6, wherein the convex portions and the concave portions are arranged such that a position of a lowest portion between the convex portions does not coincide with a position of a deepest bottom portion of the concave portions.

8. a substrate formed of an insulating member having light transmissivity; an antenna portion provided on the surface of the substrate and composed of a conductive member having light transmissivity; a power feeding portion for supplying power to the antenna portion; a covering member formed of an insulating member having light transmissivity, covering the power feeding portion, and having a region for scattering transmitted light; A light transmissive antenna, comprising:

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