Wiring board for antenna

Abstract

This wiring board for an antenna comprises a base layer, an antenna layer, and a ground layer. The base layer is translucent. The antenna layer is formed on one surface of the base layer. The ground layer is formed on the other surface of the base layer. One of the antenna layer and the ground layer is formed of a mesh member that has openings and is composed of electrically conductive wire rods having a line width of 10.0 µm or less. The other of the antenna layer and the ground layer is formed of a translucent electrically conductive film.

Description

Wiring board for antenna

[0001] The present invention relates to a wiring board for an antenna.

[0002] Communication devices such as mobile phones, smart devices, or tablets are provided with an antenna for transmitting and receiving radio waves. In recent years, due to the miniaturization of communication devices, it may be difficult to easily secure space for installing an antenna inside the housing. In addition, the antenna needs to be provided so that it can transmit and receive radio waves with high directivity such as millimeter waves. Therefore, the antenna may be provided on the display of the communication device. Such an antenna is required to have low visibility (non-visibility).

[0003] For example, in the antenna described in Patent Document 1, an antenna element is provided on one surface of a transparent film substrate, and a ground portion is provided on the other surface of the transparent film substrate. Each of the antenna element and the ground portion is constituted by a mesh pattern formed by thin silver wires. The line width of the thin wire is 1.0 μm or more and less than 5.0 μm. The thickness of the transparent film substrate is 30 μm or more and 300 μm or less. The thin silver wire contains a plurality of silver particles dispersed in a polymer. The ratio of the plurality of silver particles contained in the thin silver wire is 70% by volume or more.

[0004] Patent No. 7454660

[0005] Patent Document 1 describes that with the above-described antenna configuration, it is possible to make the antenna less visible while ensuring the conductivity of the thin wire. However, in the above-described antenna configuration, moiré occurs due to the antenna element and the ground portion, so the antenna is significantly visible. Therefore, it is difficult to improve the non-visibility of the antenna.

[0006] An object of the present invention is to provide a wiring board for an antenna with improved non-visibility.

[0007] An antenna wiring board according to one aspect of the present invention comprises a light-transmitting base layer, an antenna layer formed on one surface of the base layer, and a ground layer formed on the other surface of the base layer, wherein one of the antenna layer and the ground layer is formed of a mesh member having an opening and composed of conductive wires with a line width of 10.0 μm or less, and the other of the antenna layer and the ground layer is formed of a light-transmitting conductive film.

[0008] According to the present invention, the visibility of the wiring board for the antenna can be improved.

[0009] Figure 1 is a plan view of a communication device on which a wiring board according to the first embodiment of the present invention is mounted. Figure 2 is an external perspective view of the wiring board of Figure 1. Figure 3 is a cross-sectional view of the wiring board of Figure 2 taken along line A-A. Figure 4 is a partially enlarged cross-sectional view of the communication device of Figure 1. Figure 5 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 6 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 7 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 8 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 9 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 10 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 11 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 12 is a schematic process cross-sectional view illustrating the manufacturing method of the wiring board of Figure 3. Figure 13 is an external perspective view of a wiring board according to the second embodiment of the present invention. Figure 14 is a cross-sectional view of the wiring board of Figure 13 taken along line B-B. Figure 15 is a partially enlarged cross-sectional view of the communication device in the second embodiment. Figure 16 is a cross-sectional view of a wiring board illustrating a cover layer in another embodiment. Figure 17 is a partially enlarged cross-sectional view of a communication device to which the wiring board of Figure 16 is attached.

[0010] 1. First Embodiment (1) Configuration of the Antenna Wiring Board Hereinafter, an antenna wiring board (hereinafter simply referred to as a wiring board) according to one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a plan view of a communication device on which the wiring board according to the first embodiment of the present invention is mounted. In the example of Figure 1, the communication device 200 is a mobile phone. The communication device 200 may be other devices such as a smart device or a tablet. The communication device 200 includes a housing 110 and a display 120. The display 120 is arranged over substantially the entire surface of one side of the housing 110.

[0011] The wiring board 100 is provided so as to overlap a part of the display 120 of the communication device 200. Figure 2 is an external perspective view of the wiring board 100 of Figure 1. Figure 3 is a cross-sectional view of the wiring board 100 of Figure 2 along line A-A. As shown in Figures 2 and 3, the wiring board 100 comprises a base layer 10, an antenna layer 20, a ground layer 30, and a cover layer 40. In Figure 2, the cover layer 40 is not shown.

[0012] The base layer 10 is formed of a light-transmitting insulating material. The light-transmitting insulating material includes, for example, a cycloolefin polymer resin. The light-transmitting insulating material may also include organic insulating materials such as polyester resin, acrylic resin, polycarbonate resin, or polyimide resin. Alternatively, the light-transmitting insulating material may include glass or transparent ceramics. The light transmittance of the base layer 10 is, for example, 70% or more in the visible light region with a wavelength of 380 nm or more and 780 nm or less. The thickness of the base layer 10 is, for example, 20 μm or more and 200 μm or less.

[0013] The antenna layer 20 is formed on one surface of the base layer 10. In plan view, the antenna layer 20 has a substantially square shape. In plan view, the length L of each side of the antenna layer 20 is substantially equal to λ / 2, where λ is the wavelength of the radio waves transmitted and received by the antenna layer 20. In this embodiment, as shown in the dashed-dotted callout in Figure 2, the antenna layer 20 is formed of a mesh member. The sheet resistance of the mesh member is, for example, 1Ω / □ or less. The mesh member is composed of a plurality of wires 21 and a plurality of wires 22 and has a plurality of openings 23.

[0014] Specifically, the multiple wires 21 extend in a first direction. The multiple wires 22 extend in a second direction that intersects (orthogonal in this example) the first direction. The region enclosed by the multiple wires 21 and 22 becomes the multiple openings 23 in the mesh member. Each wire 21, 22 is made of a conductive material. The conductive material includes, for example, copper or a copper alloy. The wire width of each wire 21, 22 is, for example, 1.0 μm or more. Also, the wire width of each wire 21, 22 is 10.0 μm or less. The thickness of each wire 21, 22 is, for example, 0.5 μm or more and 20 μm or less.

[0015] The ground layer 30 is formed on the other surface of the base layer 10. In this embodiment, the ground layer 30 is formed of a light-transmitting conductive film. The conductive film is formed of, for example, indium tin oxide (ITO) containing tin oxide. The sheet resistance of the conductive film is, for example, 100 Ω / □ or less. The light transmittance of the ground layer 30 is, for example, 70% or more in the visible light region. The thickness of the ground layer 30 is, for example, 20 μm or more and 200 μm or less.

[0016] The cover layer 40 is formed on one surface of the base layer 10 using a translucent insulating material so as to cover the antenna layer 20. The cover layer 40 may be formed from the same material as the base layer 10. In this example, the cover layer 40 has an uneven shape that follows the pattern of the mesh member forming the antenna layer 20. Therefore, the thickness of the cover layer 40 in the portion that overlaps the wires 21 and 22 of the antenna layer 20 is different from the thickness of the portion within the opening 23 of the antenna layer 20. The cover layer 40 does not need to be present within the opening 23 of the antenna layer 20, except for the side portions of the wires 21 and 22. On the other hand, the thickness of the portion of the cover layer 40 that overlaps the wires 21 and 22 is, for example, 1 μm or more and 30 μm or less.

[0017] Figure 4 is a partially enlarged cross-sectional view of the communication device 200 shown in Figure 1. As shown in Figure 4, the ground layer 30 of the wiring board 100 is bonded to the display 120 of the communication device 200 via a light-transmitting adhesive layer 130. A protective layer 150, such as a cover glass, is bonded to the cover layer 40 of the wiring board 100 via a light-transmitting adhesive layer 140. The adhesive layers 130 and 140 may be transparent double-sided tape. In this way, the wiring board 100 is attached to the display 120 of the communication device 200.

[0018] (2) Method for Manufacturing a Wired Board Figures 5 to 12 are schematic cross-sectional views illustrating the manufacturing method of the wired board 100 shown in Figure 3. Note that the cross-sectional views in Figures 5 to 12 correspond to the cross-sectional view taken along line A-A in Figure 2. First, as shown in Figure 5, a base layer 10 having one flat surface and the other flat surface is prepared. The base layer 10 may be formed by coating a photosensitive resin precursor onto a support layer (not shown) and exposing the photosensitive resin precursor with ultraviolet light. In this case, the support layer is removed from the base layer 10 before the step of forming a ground layer 30 on the other surface of the base layer 10, which will be described later.

[0019] Next, as shown in Figure 6, a base layer 20A is formed on one surface of the base layer 10. The base layer 20A contains, for example, ITO. Subsequently, as shown in Figure 7, a thin film layer 20B is formed on the base layer 20A. The thin film layer 20B contains, for example, copper. Both the base layer 20A and the thin film layer 20B may be formed by sputtering. Furthermore, if the thin film layer 20B has sufficient adhesion to the base layer 10, the base layer 20A may not be formed.

[0020] Subsequently, as shown in Figure 8, a plating resist layer 50 having a predetermined pattern opening 51 is formed on the thin film layer 20B. The pattern opening 51 has a mesh-like pattern. The plating resist layer 50 may also be formed by coating a photoresist onto the thin film layer 20B and then exposing and developing the photoresist in a predetermined pattern. Next, as shown in Figure 9, a plating layer 20C is formed on the thin film layer 20B in areas where the plating resist layer 50 is not formed, i.e., on each portion of the thin film layer 20B exposed through the pattern opening 51. The plating layer 20C may contain, for example, copper or a copper alloy and may be formed by electroplating.

[0021] Next, as shown in Figure 10, the plating resist layer 50 is removed. Then, as shown in Figure 11, the unnecessary portions of the thin film layer 20B and the underlayer 20A, i.e., the portions of the thin film layer 20B and the underlayer 20A that are exposed from the plating layer 20C, are removed. The thin film layer 20B and the underlayer 20A may be removed by wet etching or dry etching. This forms the mesh member as the antenna layer 20.

[0022] Specifically, the base layer 20A extending in the first direction, the thin film layer 20B formed on it, and the plating layer 20C formed on it constitute the wires 21 of the antenna layer 20. The base layer 20A extending in the second direction, the thin film layer 20B formed on it, and the plating layer 20C formed on it constitute the wires 22 of the antenna layer 20. The area surrounded by the multiple wires 21 and the multiple wires 22 becomes the multiple openings 23 in the mesh member. Note that the base layer 20A and the thin film layer 20B are not shown in Figure 12.

[0023] Next, as shown in Figure 12, a cover layer 40 is formed on one surface of the base layer 10 so as to cover the antenna layer 20. The cover layer 40 may be formed by coating a photosensitive resin precursor on one surface of the base layer 10 so as to cover the antenna layer 20 and exposing the photosensitive resin precursor with ultraviolet light. Subsequently, a ground layer 30 is formed on the other surface of the base layer 10. The ground layer 30 may be formed by sputtering a light-transmitting conductive film. This completes the wiring board 100 shown in Figure 3.

[0024] (3) Effects In the wiring board 100 according to this embodiment, an antenna layer 20 is formed on one surface of a light-transmitting base layer 10, and a ground layer 30 is formed on the other surface of the base layer 10. The antenna layer 20 is made of a mesh member composed of conductive wires 21 and 22 and having an opening 23. The ground layer 30 is made of a light-transmitting conductive film.

[0025] With this configuration, moiré patterns do not occur even when the antenna layer 20 and the ground layer 30 are stacked. Furthermore, since the line width of the wires 21 and 22 constituting the mesh member is 10.0 μm or less, they are hardly visible. This improves the visibility of the wiring board 100. In addition, the sheet resistance value of the antenna layer 20 can be easily reduced. Therefore, the gain of the antenna layer 20 can be improved.

[0026] The mesh member is made of copper or a copper alloy. In this case, the sheet resistance can be easily reduced while maintaining the durability of the mesh member. Specifically, the sheet resistance of the mesh member is 1 Ω / □ or less. Therefore, the sheet resistance of the mesh member can be sufficiently reduced. In addition, the wire width of the wires 21 and 22 is 1.0 μm or more. This improves the durability of the mesh member.

[0027] The antenna layer 20, formed from a mesh member, is covered by a translucent cover layer 40. This configuration makes it easy to prevent corrosion of the antenna layer 20 even if the wires 21 and 22 constituting the mesh member do not have very high corrosion resistance. Furthermore, the conductive film is formed from ITO. This allows for a relatively low sheet resistance value while maintaining the translucency of the conductive film.

[0028] 2. Second Embodiment (1) Configuration of the Wiring Board The differences between the wiring board 100 according to the second embodiment of the present invention and the wiring board 100 according to the first embodiment will be explained. Figure 13 is an external perspective view of the wiring board 100 according to the second embodiment of the present invention. Figure 14 is a cross-sectional view of the wiring board 100 of Figure 13 taken along line B-B. As shown in Figures 13 and 14, in this embodiment, the wiring board 100 comprises a base layer 10, an antenna layer 20, a ground layer 30, and a cover layer 40. In Figure 13, the cover layer 40 is not shown.

[0029] The base layer 10 in this embodiment has the same configuration as the base layer 10 in the first embodiment. The antenna layer 20 has the same configuration as the antenna layer 20 in the first embodiment, except that it is formed of a light-transmitting conductive film instead of a mesh member. The conductive film is formed of, for example, ITO. The sheet resistance of the conductive film is, for example, 100 Ω / □ or less. The light transmittance of the antenna layer 20 is, for example, 70% or more in the visible light region. The thickness of the antenna layer 20 is, for example, 20 μm or more and 200 μm or less.

[0030] The ground layer 30 is not formed of a light-transmitting conductive film, and has the same configuration as the ground layer 30 in the first embodiment, except that it is formed of a mesh member, as shown by the dashed-dotted line in Figure 13. The sheet resistance value of the mesh member is, for example, 1 Ω / □ or less. The mesh member is composed of a plurality of wires 31 and a plurality of wires 32, and has a plurality of openings 33.

[0031] Specifically, the multiple wires 31 extend in a first direction. The multiple wires 32 extend in a second direction. The region enclosed by the multiple wires 31 and the multiple wires 32 becomes the multiple openings 33 in the mesh member. Each wire 31, 32 is made of a conductive material. The conductive material includes, for example, copper or a copper alloy. The wire width of each wire 31, 32 is, for example, 1.0 μm or more. Also, the wire width of each wire 31, 32 is 10.0 μm or less. The thickness of each wire 31, 32 is, for example, 0.5 μm or more and 20 μm or less.

[0032] The cover layer 40 is the same as the cover layer 40 in the first embodiment, except that it is formed on the other surface of the base layer 10 so as to cover the ground layer 30 rather than the antenna layer 20. Therefore, in this example, the cover layer 40 has an uneven shape that follows the pattern of the mesh member forming the ground layer 30. Consequently, in the cover layer 40, the thickness of the portion of the ground layer 30 that overlaps with the wires 31 and 32 is different from the thickness of the portion of the ground layer 30 that is inside the opening 33. Except for the side portions of the wires 31 and 32, the cover layer 40 does not need to be present inside the opening 33 of the ground layer 30. On the other hand, the thickness of the portion of the cover layer 40 that overlaps with the wires 31 and 32 is, for example, 1 μm or more and 30 μm or less.

[0033] Figure 15 is a partially enlarged cross-sectional view of the communication device 200 in the second embodiment. As shown in Figure 15, in this embodiment, the cover layer 40 of the wiring board 100 is bonded to the display 120 of the communication device 200 via an adhesive layer 130. A protective layer 150 is bonded to the antenna layer 20 of the wiring board 100 via an adhesive layer 140. In this way, the wiring board 100 is attached to the display 120 of the communication device 200.

[0034] (2) Method for manufacturing a wiring board Except for the following, the method for manufacturing the wiring board 100 in this embodiment is the same as the method for manufacturing the wiring board 100 in the first embodiment. In this embodiment, a mesh member is formed as a ground layer 30 on the other surface of the base layer 10 by performing the same steps as in Figures 6 to 11. In addition, an antenna layer 20 is formed by forming a mask having a predetermined pattern on one surface of the base layer 10 and sputtering a light-transmitting conductive film in the area exposed from the mask.

[0035] (3) Effects In the wiring board 100 according to this embodiment, the antenna layer 20 is formed of a light-transmitting conductive film. The ground layer 30 is formed of a mesh member composed of conductive wires 31 and 32 and having an opening 33. In this configuration as well, moiré patterns do not occur, similar to the first embodiment. Furthermore, since the line width of the wires 31 and 32 constituting the mesh member is 10.0 μm or less, they are hardly visible. This improves the visibility of the wiring board 100.

[0036] Since the ground layer 30 is formed from a mesh member, even if the area of ​​the ground layer 30 is increased, it is possible to suppress an increase in the sheet resistance value of the ground layer 30. Therefore, by increasing the area of ​​the ground layer 30, the directivity of the antenna layer 20 can be improved. In addition, the ground layer 30 is covered with a light-transmitting cover layer 40. With this configuration, even if the corrosion resistance of the wires 31 and 32 constituting the mesh member is not very high, corrosion of the ground layer 30 can be easily prevented.

[0037] (4) Modified Example In this embodiment, the plurality of openings 33 are formed uniformly throughout the entire ground layer 30. That is, the opening ratio of the ground layer 30 is uniform overall. Here, the opening ratio is the sum of the areas of the openings relative to the unit area of ​​the mesh member. However, the embodiment is not limited thereto. In the ground layer 30, the opening ratio of the region overlapping with the antenna layer 20 may be smaller than the opening ratio of the region not overlapping with the antenna layer 20.

[0038] In this case, the sheet resistance value of the region of the ground layer 30 that overlaps with the antenna layer 20 is reduced. Therefore, it is possible to easily enlarge the area of ​​the ground layer 30 while suppressing an increase in the sheet resistance value. As a result, the directivity of the antenna layer 20 can be improved by enlarging the area of ​​the ground layer 30. In addition, since the aperture ratio of the region that does not overlap with the antenna layer 20 is relatively large, the visibility of the ground layer 30 can be improved.

[0039] 3. Other Embodiments In the first embodiment, the cover layer 40 has an uneven shape that follows the pattern of the mesh member forming the antenna layer 20, but the embodiments are not limited thereto. The cover layer 40 does not have to have an uneven shape that follows the pattern of the mesh member. Figure 16 is a cross-sectional view of the wiring board 100 for illustrating the cover layer 40 in another embodiment. Figure 17 is a partially enlarged cross-sectional view of the communication device 200 to which the wiring board 100 of Figure 16 is attached.

[0040] As shown in Figure 16, in this embodiment, the cover layer 40 includes a plurality of regions 41 and a plurality of regions 42. The plurality of regions 41 each cover a plurality of wires 21, 22 of the mesh member forming the antenna layer 20. The plurality of regions 42 each fill a plurality of openings 23 of the mesh member. Here, the cover layer 40 is formed flat across the plurality of regions 41 and the plurality of regions 42.

[0041] With this configuration, as shown in Figure 17, when bonding the protective layer 150 of the communication device 200 to the cover layer 40 of the wiring board 100, it is not necessary to fill the recesses of the cover layer 40 with the adhesive layer 140. This allows the protective layer 150 to be stably bonded to the cover layer 40 using a thin adhesive layer 140. Furthermore, the flatness between the protective layer 150 and the cover layer 40 can be easily maintained.

[0042] Similarly, in the second embodiment, the cover layer 40 may not have an uneven shape along the pattern of the mesh member forming the ground layer 30. Similar to the example of FIG. 16, in the cover layer 40, a plurality of regions 41 cover a plurality of wire members 31, 32 of the mesh member forming the ground layer 30, respectively. A plurality of regions 42 may be filled in the plurality of openings 33 of the mesh member, respectively. Here, the cover layer 40 may be formed flat over the plurality of regions 41 and the plurality of regions 42.

[0043] According to this configuration, when the cover layer 40 of the wiring board 100 is adhered to the display 120 of the communication device 200, it is not necessary to fill the adhesive layer 130 in the concave portion of the cover layer 40. Thereby, the cover layer 40 can be stably adhered to the display 120 using the adhesive layer 130 having a small thickness. In addition, the flatness between the cover layer 40 and the display 120 can be easily maintained.

[0044] Further, in the above embodiment, the wiring board 100 includes the cover layer 40, but the embodiment is not limited thereto. When the mesh member forming the antenna layer 20 or the ground layer 30 has high corrosivity, the wiring board 100 may not include the cover layer 40. For example, when the mesh member is composed of a wire made of gold (Au), the mesh member hardly corrodes. Therefore, the wiring board 100 may not include the cover layer 40.

[0045] 4. Examples and Comparative Examples In the following Examples 1 and 2 and Comparative Examples 1 to 3, various wiring boards were designed by simulation. In Example 1, a wiring board according to the first embodiment was designed. That is, the antenna layer of the wiring board was formed of a mesh member, and the ground layer was formed of a conductive film. The mesh member was composed of a copper wire having a wire width of 2 μm. The sheet resistance value of the mesh member was set to 0.1 Ω / sq. The aperture ratio of the mesh member was set to 95%. The conductive film was formed of ITO. The sheet resistance value of the conductive film was set to 50 Ω / sq. The thickness of the antenna layer was set to 5 μm, and the thickness of the ground layer was set to 150 μm.

[0046] In Example 2, a wiring board according to the second embodiment was designed. That is, the antenna layer of the wiring board was formed of a conductive film, and the ground layer was formed of a mesh member. The configuration of the conductive film is the same as that of the conductive film in Example 1. The configuration of the mesh member is the same as that of the mesh member in Example 1. Further, in order to make the sheet resistance value of the conductive film coincide with the sheet resistance value of the conductive film in Example 1 while making the area of the antenna layer coincide with the area of the antenna layer in Example 1, the thickness of the antenna layer was set to 125 μm. In order to make the sheet resistance value of the mesh member coincide with the sheet resistance value of the mesh member in Example 1 while making the area of the ground layer coincide with the area of the ground layer in Example 1, the thickness of the ground layer was set to 6 μm.

[0047] In Comparative Example 1, both the antenna layer and the ground layer of the wiring board were formed of a conductive film. The configuration of the conductive film of the antenna layer and the thickness of the antenna layer are the same as the configuration of the conductive film of the antenna layer and the thickness of the antenna layer in Example 2, respectively. The configuration of the conductive film of the ground layer and the thickness of the ground layer are the same as the configuration of the conductive film of the ground layer and the thickness of the ground layer in Example 1, respectively.

[0048] In Comparative Example 2, both the antenna layer and the ground layer of the wiring board were formed of a mesh member. The configuration of the mesh member of the antenna layer and the thickness of the antenna layer are the same as the configuration of the mesh member of the antenna layer and the thickness of the antenna layer in Example 1, respectively. The configuration of the mesh member of the ground layer and the thickness of the ground layer are the same as the configuration of the mesh member of the ground layer and the thickness of the ground layer in Example 2, respectively.

[0049] In Comparative Example 3, a wiring board similar to Example 2 was designed except that the line width of the wire forming the mesh member was 15 μm instead of 2 μm. The non-visibility of the wiring boards according to these Examples 1, 2 and Comparative Examples 1 to 3 was determined. In the determination, an example with good non-visibility was evaluated as "〇", and an example with poor non-visibility was evaluated as "×". The evaluation results are shown in Table 1.

[0050]

[0051] As shown in Table 1, in Example 1, the visibility of the wiring board was good, so it was evaluated as "○". Similarly, in Example 2, the visibility of the wiring board was good, so it was evaluated as "○". On the other hand, in Comparative Example 1, the visibility was reduced because both the thickness of the antenna layer and the ground layer were large. Therefore, it was evaluated as "×". In Comparative Example 2, moiré patterns were generated by the mesh members of the antenna layer and the ground layer, so the visibility was reduced. Therefore, it was evaluated as "×". In Comparative Example 3, the visibility was reduced because the wire width was large. Therefore, it was evaluated as "×".

[0052] From the above comparison results, it was confirmed that the visibility of the wiring board can be improved by forming one of the antenna layer and ground layer with a mesh material and the other with a conductive film, and by making the wire width of the wire material constituting the mesh material less than 15 μm.

[0053] 5. Correspondence between parts of the embodiment and components of the claims Below, examples of the correspondence between components of the claims and components of the embodiments will be described. Various other elements having the configuration or function described in the claims can also be used as components of the claims.

[0054] In the above embodiment, the base layer 10 is an example of a base layer, the antenna layer 20 is an example of an antenna layer, the ground layer 30 is an example of a ground layer, and the wires 21, 22, 31, and 32 are examples of wires. The openings 23 and 33 are examples of openings, the wiring board 100 is an example of an antenna wiring board, and the cover layer 40 is an example of a cover layer.

[0055] 6. Summary of Embodiments (Section 1) The antenna wiring board according to Section 1 comprises a light-transmitting base layer, an antenna layer formed on one surface of the base layer, and a ground layer formed on the other surface of the base layer, wherein one of the antenna layer and the ground layer is made of a mesh member having an opening and composed of conductive wire with a line width of 10.0 μm or less, and the other of the antenna layer and the ground layer is made of a light-transmitting conductive film.

[0056] In this antenna wiring board, an antenna layer is formed on one surface of a translucent base layer, and a ground layer is formed on the other surface of the base layer. One of the antenna layer and the ground layer is formed from a mesh member. The other of the antenna layer and the ground layer is formed from a translucent conductive film. With this configuration, moiré patterns do not occur even when the antenna layer and the ground layer are laminated. The wire width of the wires constituting the mesh member is 10.0 μm or less, so it is hardly visible. This improves the visibility of the antenna wiring board.

[0057] (Clause 2) In the antenna wiring board described in paragraph 1, the antenna layer may be formed of the conductive film, and the ground layer may be formed of the mesh member.

[0058] This configuration makes it possible to suppress the increase in the sheet resistance of the ground layer even when the area of ​​the ground layer is increased. Therefore, by increasing the area of ​​the ground layer, the directivity of the antenna layer can be improved.

[0059] (Clause 3) In the antenna wiring board described in paragraph 1, the antenna layer may be formed by the mesh member, and the ground layer may be formed by the conductive film.

[0060] In this case, the sheet resistance of the antenna layer can be easily reduced. This allows for an improvement in the gain of the antenna layer.

[0061] (Paragraph 4) The antenna wiring board described in paragraph 1 or 2 may further include a light-transmitting cover layer that covers the layer formed by the mesh member among the antenna layer and the ground layer.

[0062] In this case, corrosion of the layer formed by the mesh member can be easily prevented.

Claims

1. An antenna wiring board comprising: a light-transmitting base layer; an antenna layer formed on one surface of the base layer; and a ground layer formed on the other surface of the base layer, wherein one of the antenna layer and the ground layer is formed of a mesh member having an opening and composed of conductive wire with a line width of 10.0 μm or less; and the other of the antenna layer and the ground layer is formed of a light-transmitting conductive film.

2. The antenna wiring board according to claim 1, wherein the antenna layer is formed of the conductive film and the ground layer is formed of the mesh member.

3. The antenna wiring board according to claim 1, wherein the antenna layer is formed by the mesh member and the ground layer is formed by the conductive film.

4. The antenna wiring board according to claim 1 or 2, further comprising a cover layer that is translucent and covers the layer formed by the mesh member among the antenna layer and the ground layer.

Images