Wiring board and method for manufacturing the same

Abstract

To provide a wiring board and a manufacturing method thereof that suppress disconnection of wiring in a wiring pattern area near a power supply portion.SOLUTION: A wiring board 10 includes a transparent substrate 11, a wiring pattern region 20 disposed on the substrate 11 and including a plurality of first directional wires 21, and a power supply portion electrically connected to the plurality of first directional wires 21 in the wiring pattern region 20. The first directional wire 21 has a first region located near the power supply portion and a second region other than the first region. The line width W3 of the first directional wires 21 in the first region is larger than the line width W1 of the first directional wires 21 in the second region.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] An embodiment of the present disclosure relates to a wiring substrate and a method for manufacturing the wiring substrate. [Background technology]

[0002] Currently, mobile terminal devices such as smartphones and tablets are becoming increasingly sophisticated, smaller, thinner, and lighter. These mobile terminal devices use multiple communication bands, requiring multiple antennas corresponding to the communication bands. For example, mobile terminal devices are equipped with multiple antennas, such as a telephone antenna, a Wi-Fi (Wireless Fidelity) antenna, a 3G (Generation) antenna, a 4G (Generation) antenna, an LTE (Long Term Evolution) antenna, a Bluetooth (registered trademark) antenna, and an NFC (Near Field Communication) antenna. However, as mobile terminal devices become smaller, the space available for antenna installation is limited, limiting the degree of freedom in antenna design. Furthermore, because antennas are built into a limited space, radio wave sensitivity is not always satisfactory.

[0003] For this reason, film antennas that can be mounted in the display area of ​​mobile terminal devices have been developed. These film antennas are transparent antennas in which an antenna pattern is formed on a transparent substrate, and the antenna pattern is formed by a mesh-like conductive mesh layer that consists of conductor portions as formed portions of an opaque conductive layer and numerous openings as non-formed portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-66610 [Patent Document 2] Patent No. 5636735 specification [Patent Document 3] Patent No. 5695947 specification Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional film antennas, the area of ​​the conductive mesh layer near the power supply point tends to have a higher current density than other areas, so when the film antenna is used for a long period of time, the wiring near the power supply point is more likely to break than other areas of the conductive mesh layer.

[0006] The present embodiment provides a wiring board and a method for manufacturing the wiring board that can prevent the wiring in the wiring pattern area from being broken near the power supply portion.

[0007] In addition, in a film antenna, it is preferable to cover the conductive mesh layer and the power supply part with a protective layer to protect them. However, since the power supply part that supplies electricity to the conductive mesh layer is generally made of a uniform metal plate member with no gaps over the entire surface, there is a risk that the protective layer covering the power supply part and the power supply part may peel off.

[0008] The present embodiment provides a wiring board and a method for manufacturing the wiring board that can prevent the protective layer and the power supply portion from peeling off from each other. [Means for solving the problem]

[0009] The wiring board according to the present embodiment is a wiring board comprising: a transparent substrate; a wiring pattern region arranged on the substrate and including a plurality of first directional wirings; and a power supply section electrically connected to the plurality of first directional wirings in the wiring pattern region, wherein the first directional wirings have a first region located near the power supply section and a second region other than the first region, and the line width of the first directional wirings in the first region is thicker than the line width of the first directional wirings in the second region.

[0010] In the wiring board according to this embodiment, the wiring pattern region may include a plurality of second directional wirings connecting the plurality of first directional wirings, and the first region may be located at least between the second directional wiring closest to the power supply portion and the power supply portion.

[0011] In the wiring board according to the present embodiment, the first direction wiring in the first region may have a planar shape in which the line width gradually narrows with increasing distance from the power supply portion.

[0012] In the wiring board according to this embodiment, the line width of the first region of the first direction wiring located near the widthwise center of the wiring pattern region may be narrower than the line width of the first region of the first direction wiring located near the widthwise edge of the wiring pattern region.

[0013] In the wiring board according to the present embodiment, the length of the first region along the longitudinal direction of the wiring pattern region may be 0.1 mm or more and 0.5 mm or less.

[0014] In the wiring board according to the present embodiment, the line width of the first directional wiring in the first region may be 150% or more of the line width of the first directional wiring in the second region.

[0015] In the wiring board according to the present embodiment, the line width of the first direction wiring in the second region may be in the range of 0.1 μm to 5.0 μm.

[0016] The wiring board according to the present embodiment is a wiring board comprising a transparent substrate, a wiring pattern area disposed on the substrate and including a plurality of first-directional wirings and a plurality of second-directional wirings, and a power supply section electrically connected to the plurality of first-directional wirings and the plurality of second-directional wirings in the wiring pattern area, and the area surrounded by the power supply section, the first-directional wirings, and the second-directional wirings is a non-opening.

[0017] A method for manufacturing a wiring board according to the present embodiment is a method for manufacturing a wiring board, comprising the steps of: preparing a transparent substrate; and forming, on the substrate, a wiring pattern region including a plurality of first directional wirings; and a power supply section electrically connected to the plurality of first directional wirings in the wiring pattern region, wherein the first directional wirings have a first region located near the power supply section and a second region other than the first region, and the line width of the first directional wirings in the first region is thicker than the line width of the first directional wirings in the second region.

[0018] According to the embodiment of the present disclosure, it is possible to prevent the wiring in the wiring pattern area from being broken near the power supply portion.

[0019] The wiring board according to the present embodiment is a wiring board comprising: a transparent substrate; a wiring pattern area arranged on the substrate and including a plurality of wirings; and a power supply section electrically connected to the plurality of wirings in the wiring pattern area, wherein the power supply section has a plurality of through holes or a plurality of non-through recesses.

[0020] In the wiring board according to this embodiment, the plurality of through holes or the plurality of non-through recesses may be arranged in a plurality of rows and columns within the plane of the power supply portion.

[0021] In the wiring board according to this embodiment, the plurality of through holes or the plurality of non-through recesses may be arranged at uniform intervals from one another in at least one direction.

[0022] In the wiring board according to the present embodiment, the width of each through hole or each non-through recess may be 50 μm or more and 500 μm or less.

[0023] In the wiring board according to the present embodiment, the pitch of the plurality of through holes or the plurality of non-through recesses may be 100 μm or more and 500 μm or less.

[0024] In the wiring board according to the present embodiment, a protective layer may be formed on the board so as to cover the wiring pattern area and the power supply portion.

[0025] In the wiring board according to the present embodiment, the wiring may have a line width in the range of 0.1 μm to 5.0 μm.

[0026] In the wiring board according to this embodiment, the wiring pattern region may have a function as an antenna.

[0027] In the wiring board according to this embodiment, the area or pitch of the plurality of through holes or the plurality of non-through recesses may be different between an area close to the wiring pattern area and an area far from the wiring pattern area.

[0028] The method for manufacturing a wiring board according to this embodiment is a method for manufacturing a wiring board, and includes the steps of preparing a transparent substrate, and forming, on the substrate, a wiring pattern area including a plurality of wirings, and a power supply section electrically connected to the plurality of wirings in the wiring pattern area, wherein the power supply section has a plurality of through holes or non-through recesses. [Effects of the Invention]

[0029] According to the embodiment of the present disclosure, it is possible to prevent the protective layer and the power supply part from peeling off from each other. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a plan view showing a wiring board according to a first embodiment. [Figure 2] FIG. 2 is an enlarged plan view showing the wiring board according to the first embodiment (an enlarged view of a portion II in FIG. 1). [Figure 3] 3 is a cross-sectional view (a cross-sectional view taken along line III-III in FIG. 2) showing the wiring board according to the first embodiment. [Figure 4] 4 is a cross-sectional view (a cross-sectional view taken along line IV-IV in FIG. 2) showing the wiring board according to the first embodiment. [Figure 5] FIG. 5 is an enlarged plan view showing the wiring board according to the first embodiment (an enlarged view of a portion V in FIG. 1). [Figure 6] 6(a) to 6(i) are cross-sectional views showing a method for manufacturing a wiring substrate according to the first embodiment. [Figure 7] FIG. 7 is a plan view showing the image display device according to the first embodiment. [Figure 8] FIG. 8 is a partially enlarged plan view showing an image display device according to a modified example of the first embodiment. [Figure 9] FIG. 9 is an enlarged plan view showing a wiring board according to a first modification of the first embodiment. [Figure 10] FIG. 10 is an enlarged plan view showing a wiring board according to a second modification of the first embodiment. [Figure 11] FIG. 11 is an enlarged plan view showing a wiring board according to a third modification of the first embodiment. [Figure 12] FIG. 12 is an enlarged plan view showing a wiring board according to a fourth modification of the first embodiment. [Figure 13] FIG. 13 is an enlarged plan view showing a wiring board according to a fifth modified example of the first embodiment. [Figure 14] FIG. 14 is an enlarged plan view showing a wiring board according to a sixth modified example of the first embodiment. [Figure 15] FIG. 15 is a plan view showing a wiring board according to a second embodiment. [Figure 16] 16 is an enlarged plan view showing the wiring board according to the second embodiment (an enlarged view of a portion XVI in FIG. 15). [Figure 17] 17 is a cross-sectional view (cross-sectional view taken along line XVII-XVII in FIG. 16) showing the power supply portion of the wiring board according to the second embodiment. [Figure 18] FIG. 18 is a plan view showing an image display device according to a second embodiment. [Figure 19] 19(a) to 19(c) are enlarged plan views showing a wiring board according to a first modified example of the second embodiment. [Figure 20] 20(a) and 20(b) are enlarged plan views showing a wiring board according to a second modification of the second embodiment. [Figure 21]FIG. 21 is an enlarged plan view showing a wiring board according to a third modification of the second embodiment. [Figure 22] FIG. 22 is a cross-sectional view showing a power supply portion of a wiring board according to a fourth modification of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] The figures shown below are schematic illustrations. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made within the scope of the technical concept. In the figures shown below, identical parts are denoted by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are examples of embodiments, and are not limited to these and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include substantially the same state in addition to their strict meanings.

[0032] In the following embodiments, the "X direction" refers to a direction parallel to one side of the substrate. The "Y direction" refers to a direction perpendicular to the X direction and parallel to another side of the substrate. The "Z direction" refers to a direction perpendicular to both the X and Y directions and parallel to the thickness direction of the wiring substrate. The "front surface" refers to the surface on the positive side of the Z direction, on which wiring is provided with respect to the substrate. The "back surface" refers to the surface on the negative side of the Z direction, on the opposite side to the surface on which wiring is provided with respect to the substrate.

[0033] (First embodiment) The first embodiment will be described with reference to Figures 1 to 15. Figures 1 to 15 are diagrams showing the first embodiment.

[0034] [Wiring board configuration] The configuration of the wiring board according to this embodiment will be described with reference to Figures 1 to 5. Figures 1 to 5 are diagrams showing the wiring board according to this embodiment.

[0035] 1, a wiring board 10 according to this embodiment is disposed on, for example, a display of an image display device. Such wiring board 10 includes a transparent substrate 11 and a wiring pattern area 20 disposed on substrate 11. A power supply unit 40 is electrically connected to wiring pattern area 20.

[0036] Of these, substrate 11 has a substantially rectangular shape in a plan view, with its longitudinal direction parallel to the Y direction and its lateral direction parallel to the X direction. Substrate 11 is transparent and substantially flat, with a substantially uniform thickness overall. The length L1 of substrate 11 in the longitudinal direction (Y direction) can be selected, for example, from 100 mm to 200 mm, and the length L2 of substrate 11 in the lateral direction (X direction) can be selected, for example, from 50 mm to 100 mm. Note that substrate 11 may have rounded corners.

[0037] The material of substrate 11 may be any material that is transparent in the visible light range and electrically insulating. In this embodiment, the material of substrate 11 is polyethylene terephthalate, but is not limited thereto. The material of substrate 11 is preferably an organic insulating material, such as a polyester resin such as polyethylene terephthalate, an acrylic resin such as polymethyl methacrylate, a polycarbonate resin, a polyimide resin, a polyolefin resin such as cycloolefin polymer, or a cellulose resin such as triacetyl cellulose. The material of substrate 11 may also be selected appropriately from glass, ceramics, and the like depending on the application. While the illustrated example shows substrate 11 formed of a single layer, this is not limiting and multiple substrates or layers may be stacked. Substrate 11 may also be in the form of a film or a plate. Therefore, the thickness of substrate 11 is not particularly limited and can be selected appropriately depending on the application. For example, the thickness (Z direction) T1 of substrate 11 (see FIG. 3 ) may be, for example, in the range of 10 μm to 200 μm.

[0038] In this embodiment, the wiring pattern area 20 is made up of an antenna pattern area that functions as an antenna. In FIG. 1, a plurality of (three) wiring pattern areas 20 are formed on the substrate 11, and each corresponds to a different frequency band. That is, the plurality of wiring pattern areas 20 have a length (length in the Y direction) L a The lengths L of the wiring pattern area 20 are different from each other and correspond to specific frequency bands. a When the wiring board 10 is disposed on, for example, a display 91 of an image display device 90 (see FIG. 7 described later), each wiring pattern area 20 may correspond to any one of a telephone antenna, a WiFi antenna, a 3G antenna, a 4G antenna, a 5G antenna, an LTE antenna, a Bluetooth (registered trademark) antenna, an NFC antenna, etc.

[0039] Each wiring pattern region 20 has a substantially rectangular shape in a plan view. The longitudinal direction of each wiring pattern region 20 is parallel to the Y direction, and the lateral direction (width direction) of each wiring pattern region 20 is parallel to the X direction. The length L of each wiring pattern region 20 in the longitudinal direction (Y direction) is a can be selected, for example, in the range of 3 mm to 100 mm, and the width W a can be selected, for example, in the range of 1 mm to 10 mm.

[0040] In the wiring pattern region 20, metal wires are formed in a lattice or mesh shape, and have a repeated pattern in the X and Y directions. That is, the wiring pattern region 20 has a pattern shape made up of a portion extending in the X direction (second-directional wiring 22) and a portion extending in the Y direction (first-directional wiring 21).

[0041] As shown in FIG. 2, each wiring pattern region 20 includes a plurality of first-directional wirings (antenna wirings) 21 that function as antennas, and a plurality of second-directional wirings (antenna connecting wirings) 22 that connect the plurality of first-directional wirings 21. Specifically, the plurality of first-directional wirings 21 and the plurality of second-directional wirings 22 are integrated as a whole to form a lattice or mesh shape. Each first-directional wiring 21 extends in a direction (longitudinal direction, Y direction) corresponding to the frequency band of the antenna, and each second-directional wiring 22 extends in a direction (width direction, X direction) perpendicular to the first-directional wiring 21. The first-directional wiring 21 has a length L corresponding to a predetermined frequency band. a (See FIG. 1 for the length of the wiring pattern region 20 described above), and thereby function mainly as an antenna. On the other hand, the second directional wirings 22, by connecting these first directional wirings 21 together, function to prevent problems such as breakage of the first directional wirings 21 and loss of electrical connection between the first directional wirings 21 and the power supply unit 40.

[0042] In each wiring pattern region 20, a plurality of openings 23 are formed by being surrounded by adjacent first-directional wires 21 and adjacent second-directional wires 22. Each opening 23 has a substantially rectangular or square shape in plan view. The area of ​​the openings 23 is uniform at least within a second region 27, which will be described later. Furthermore, the transparent substrate 11 is exposed through each opening 23. Therefore, by increasing the total area of ​​the openings 23 per unit area of ​​the wiring pattern region 20, the transparency of the wiring substrate 10 as a whole can be increased.

[0043] As shown in FIG. 2, the multiple first directional wires 21 are arranged at intervals (pitch P1) from one another in the width direction (X direction) of the wiring pattern region 20. In this case, the multiple first directional wires 21 are arranged at uniform intervals from one another along the width direction (X direction) of the wiring pattern region 20. Furthermore, the first directional wires 21 and the second directional wires 22 are arranged at equal intervals from one another. That is, the multiple first directional wires 21 are arranged at equal intervals from one another, and the pitch P1 can be, for example, in the range of 0.01 mm to 1 mm. Furthermore, the multiple second directional wires 22 are arranged at equal intervals from one another, and the pitch P2 can be, for example, in the range of 0.01 mm to 1 mm. In this way, by arranging the multiple first directional wires 21 and the multiple second directional wires 22 at equal intervals, there is no variation in the size of the openings 23 at least within a second region 27 described later, and the wiring pattern region 20 can be made difficult to see with the naked eye. Furthermore, at least within the second region 27 described below, the pitch P1 of the first directional wirings 21 is equal to the pitch P2 of the second directional wirings 22. Therefore, within the second region 27, each opening 23 has a substantially square shape in a plan view, and the transparent substrate 11 is exposed through each opening 23. In this way, by increasing the area of ​​each opening 23, the transparency of the wiring substrate 10 as a whole can be improved. The length L3 of one side of each opening 23 can be, for example, in the range of 0.01 mm to 1 mm. While the first directional wirings 21 and the second directional wirings 22 are orthogonal to each other, this is not a limitation and they may intersect at an acute or obtuse angle. The shape of the openings 23 is preferably the same shape and size at least within the second region 27 described below, but it does not have to be uniform across the entire surface; for example, it may vary depending on the location.

[0044] 3, each of the first directional wirings 21 has a substantially rectangular or square cross section perpendicular to its longitudinal direction (X-direction cross section). The cross-sectional shapes of the first directional wirings 21 differ between a first region 26 and a second region 27, which will be described later. Within the first region 26 or the second region 27, the cross-sectional shape of the first directional wirings 21 is substantially uniform along the longitudinal direction (Y direction) of the first directional wirings 21.

[0045] 4, the shape of a cross section (Y-direction cross section) perpendicular to the longitudinal direction of each second directional wiring 22 is substantially rectangular or square, and is substantially the same as the cross section (X-direction cross section) of the first directional wiring 21 in the above-described second region 27. In this case, the cross section shape of the second directional wiring 22 is substantially uniform along the longitudinal direction (X direction) of the second directional wiring 22. The cross section shapes of the first directional wiring 21 and the second directional wiring 22 do not necessarily have to be substantially rectangular or square, and may be, for example, a substantially trapezoidal shape in which the front side (positive side in the Z direction) is narrower than the back side (negative side in the Z direction), or a shape in which the side surfaces located on both longitudinal sides are curved.

[0046] In this embodiment, the line width W1 (length in the X direction, see FIG. 3) of the first-directional wiring 21 and the line width W2 (length in the Y direction, see FIG. 4) of the second-directional wiring 22 in the second region 27 described later are not particularly limited and can be appropriately selected depending on the application. For example, the line width W1 of the first-directional wiring 21 can be selected in the range of 0.1 μm to 5.0 μm, and the line width W2 of the second-directional wiring 22 can be selected in the range of 0.1 μm to 5.0 μm. Furthermore, the height H1 (length in the Z direction, see FIG. 3) of the first-directional wiring 21 and the height H2 (length in the Z direction, see FIG. 4) of the second-directional wiring 22 are not particularly limited and can be appropriately selected depending on the application, for example, can be selected in the range of 0.1 μm to 5.0 μm.

[0047] As shown in FIG. 5, the plurality of first directional wirings 21 are electrically connected to the power supply unit 40 on the negative side in the Y direction. Each of the plurality of first directional wirings 21 has a first region 26 located near the power supply unit 40 and a second region 27 other than the first region 26. The first region 26 is a region of the first directional wirings 21 located on the negative side in the Y direction and includes a connection portion with the power supply unit 40. The second region 27 is a region of the first directional wirings 21 located on the positive side in the Y direction and is farther from the power supply unit 40 than the first region 26. In the longitudinal direction (Y direction) of the wiring pattern region 20, the length of the second region 27 is longer than that of the first region 26.

[0048] The line width W3 of the first directional wiring 21 in the first region 26 is larger than the line width W1 of the first directional wiring 21 in the second region 27. That is, the line width of the first directional wiring 21 is larger in the first region 26 located near the connection portion with the power supply unit 40, and is smaller in the second region 27 located away from the power supply unit 40. This makes it possible to increase the line width W3 of the first directional wiring 21 in the connection portion with the power supply unit 40 (first region 26), which is a region where the current density is higher than in other portions, and to prevent breakage of the first directional wiring 21.

[0049] The line width W3 of the first directional wirings 21 in the first region 26 is preferably 150% or more (1.5W1≦W3) of the line width W1 of the first directional wirings 21 in the second region 27. Specifically, the line width W3 of the first directional wirings 21 in the first region 26 can be selected in the range of 0.15 μm or more. In this embodiment, the line widths W3 of all of the multiple first directional wirings 21 are the same.

[0050] In FIG. 5, the first region 26 has a planar shape of a rectangle elongated in the Y direction. The line width W3 of the first region 26 is approximately uniform within the first region 26 along the longitudinal direction (Y direction) of the first directional wiring 21. The second region 27 has a planar shape of a rectangle elongated in the Y direction. The line width W1 of the second region 27 is approximately uniform within the second region 27 along the longitudinal direction (Y direction) of the first directional wiring 21. The height H1 (length in the Z direction, see FIG. 3) of the first directional wiring 21 is uniform between the first region 26 and the second region 27. On the other hand, the line width W2 of the second directional wiring 22 is the same between the second directional wiring 22 located near the power supply unit 40 and the second directional wiring 22 located away from the power supply unit 40.

[0051] The first region 26 is preferably located at least between the second directional wiring 22 closest to the power supply unit 40 (located closest to the negative Y-direction side) and the power supply unit 40. In FIG. 5, the first region 26 is located between the second directional wiring 22 second closest to the power supply unit 40 (located second closest to the positive Y-direction side as viewed from the power supply unit 40) and the power supply unit 40. However, the first region 26 is not limited to this, and may be located between the second directional wiring 22 N-th closest to the power supply unit 40 (N is 3 or more) and the power supply unit 40.

[0052] Specifically, the length L4 in the Y direction of the first region 26 is preferably 0.1 mm or more and 0.5 mm or less. By making the length L4 in the Y direction of the first region 26 0.1 mm or more, the line width W3 of the first directional wiring 21 can be made thicker in the region near the connection with the power supply unit 40, where the current density is higher than in other regions, and disconnection of the first directional wiring 21 can be suppressed. Furthermore, by making the length L4 in the Y direction of the first region 26 0.5 mm or less, the region where the line width W3 of the first directional wiring 21 is thick does not become excessively long. This prevents the transparency of the wiring substrate 10 as a whole from being impaired.

[0053] The material of the first directional wiring 21 and the second directional wiring 22 may be any metal material having electrical conductivity. In the present embodiment, the material of the first directional wiring 21 and the second directional wiring 22 is copper, but is not limited to this. The material of the first directional wiring 21 and the second directional wiring 22 may be, for example, a metal material (including an alloy) such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel.

[0054] In the present embodiment, the overall aperture ratio At of the wiring pattern region 20 can be set, for example, in the range of 87% or more and less than 100%. By setting the overall aperture ratio At of the wiring substrate 10 in this range, the conductivity and transparency of the wiring substrate 10 can be ensured. The aperture ratio refers to the ratio (%) of the area of ​​the open region (a region where no metal parts such as the first-directional wiring 21 and the second-directional wiring 22 are present and where the substrate 11 is exposed) to the unit area of ​​a predetermined region (for example, a part of the wiring pattern region 20).

[0055] Referring again to FIG. 1 , the power supply unit 40 is electrically connected to the wiring pattern region 20. The power supply unit 40 is made of a conductive thin plate member having a substantially rectangular shape. The longitudinal direction of the power supply unit 40 is parallel to the X direction, and the lateral direction of the power supply unit 40 is parallel to the Y direction. The power supply unit 40 is disposed at the longitudinal end (the end on the negative side in the Y direction) of the substrate 11. The power supply unit 40 may be made of a metal material (including an alloy containing metal), such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel. When the wiring substrate 10 is incorporated into an image display device 90 (see FIG. 7 ), the power supply unit 40 is electrically connected to a wireless communication circuit 92 of the image display device 90. Note that the power supply unit 40 is provided on the surface of the substrate 11, but this is not limiting, and a part or all of the power supply unit 40 may be located outside the periphery of the substrate 11.

[0056] Furthermore, as shown in FIGS. 3 and 4, a protective layer 17 is formed on the surface of the substrate 11 to cover the wiring pattern region 20 and the power supply portion 40. The protective layer 17 protects the wiring pattern region 20 and the power supply portion 40 and is formed over substantially the entire surface of the substrate 11. Examples of materials that can be used for the protective layer 17 include acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate, modified resins thereof, copolymers thereof, polyester, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinyl butyral, copolymers thereof, polyurethane, epoxy resin, polyamide, and chlorinated polyolefin, and other colorless and transparent insulating resins. The thickness T2 of the protective layer 17 can be selected from a range of 0.3 μm to 100 μm. The protective layer 17 only needs to be formed to cover at least the wiring pattern region 20 of the substrate 11.

[0057] [Method of manufacturing wiring board] Next, a method for manufacturing a wiring board according to this embodiment will be described with reference to Figures 6(a) to 6(i). Figures 6(a) to 6(i) are cross-sectional views illustrating the method for manufacturing a wiring board according to this embodiment.

[0058] First, as shown in FIG. 6(a), a substrate 11 is prepared, and a conductive layer 51 is formed over substantially the entire surface of the substrate 11. In this embodiment, the thickness of the conductive layer 51 is 200 nm. However, this is not limiting, and the thickness of the conductive layer 51 can be appropriately selected within the range of 10 nm to 1000 nm. In this embodiment, the conductive layer 51 is formed by sputtering using copper. The conductive layer 51 may also be formed by plasma CVD.

[0059] 6(b), a photo-curable insulating resist 52 is applied to almost the entire surface of the substrate 11. As the photo-curable insulating resist 52, for example, an organic resin such as an epoxy resin can be used.

[0060] Next, a transparent imprint mold 53 having protrusions 53a is prepared (FIG. 6(c)), and this mold 53 and the substrate 11 are brought close to each other, and a photo-curable insulating resist 52 is spread between the mold 53 and the substrate 11. Next, light is irradiated from the mold 53 side to harden the photo-curable insulating resist 52, thereby forming an insulating layer 54. As a result, trenches 54a having a shape transferred from the protrusions 53a are formed on the surface of the insulating layer 54. The trenches 54a have a planar shape pattern corresponding to the first-directional wiring 21 and the second-directional wiring 22.

[0061] Thereafter, the mold 53 is peeled off from the insulating layer 54 to obtain the insulating layer 54 having the cross-sectional structure shown in Fig. 6(d). The mold 53 is preferably peeled off from the insulating layer 54 in the Y direction in which the longer first directional wirings 21 extend.

[0062] In this way, by forming the trenches 54a in the surface of the insulating layer 54 by the imprint method, the shape of the trenches 54a can be made fine. However, this is not limiting, and the insulating layer 54 may also be formed by the photolithography method. In this case, a resist pattern is formed by the photolithography method so as to expose the conductive layer 51 corresponding to the first-directional wirings 21 and the second-directional wirings 22.

[0063] As shown in FIG. 6(d), residues of insulating material may remain at the bottom of the trench 54a in the insulating layer 54. Therefore, the residues of insulating material are removed by wet processing using a permanganate solution or N-methyl-2-pyrrolidone, or by dry processing using oxygen plasma. By removing the residues of insulating material in this manner, trenches 54a can be formed that expose the conductive layer 51, as shown in FIG. 6(e).

[0064] 6(f), the trenches 54a in the insulating layer 54 are filled with a conductor 55. In this embodiment, the trenches 54a in the insulating layer 54 are filled with copper by electroplating using the conductive layer 51 as a seed layer.

[0065] 6(g), the insulating layer 54 is removed by wet treatment using a permanganate solution or N-methyl-2-pyrrolidone, or dry treatment using oxygen plasma.

[0066] Next, as shown in FIG. 6( h), the conductive layer 51 on the surface of the substrate 11 is removed. At this time, a wet process using hydrogen peroxide is performed to etch the conductive layer 51 so that the surface of the substrate 11 is exposed. In this manner, a wiring board 10 is obtained, which includes the substrate 11 and the wiring pattern region 20 arranged on the substrate 11. In this case, the wiring pattern region 20 includes first directional wiring 21 and second directional wiring 22. The above-mentioned conductor 55 includes the first directional wiring 21 and the second directional wiring 22. At this time, the power supply unit 40 may be formed by a portion of the conductor 55. Alternatively, a flat-plate-shaped power supply unit 40 may be separately prepared and electrically connected to the wiring pattern region 20.

[0067] 6(i), a protective layer 17 is formed so as to cover the wiring pattern region 20 and the power supply section 40 on the substrate 11. Methods for forming the protective layer 17 include roll coating, gravure coating, gravure reverse coating, microgravure coating, slot die coating, die coating, knife coating, inkjet coating, dispenser coating, kiss coating, spray coating, screen printing, offset printing, and flexographic printing.

[0068] [Operation of this embodiment] Next, the operation of the wiring board having such a configuration will be described.

[0069] As shown in FIG. 7 , the wiring board 10 is incorporated into an image display device 90 having a display 91. The wiring board 10 is disposed on the display 91. Examples of such image display devices 90 include mobile terminal devices such as smartphones and tablets. The wiring pattern region 20 of the wiring board 10 is electrically connected to a wireless communication circuit 92 of the image display device 90 via a power supply unit 40. In this way, radio waves of a predetermined frequency can be transmitted and received via the wiring pattern region 20, and communication can be performed using the image display device 90.

[0070] Generally, while radio waves are being transmitted and received using the wiring pattern region 20, the current density tends to be high in the vicinity of the power supply unit 40 in the wiring pattern region 20. Therefore, the first directional wiring 21 near the power supply unit 40 is more likely to break than other portions of the first directional wiring 21, especially when the wiring substrate 10 is used for a long period of time. In contrast, in the present embodiment, the line width W3 of the first directional wiring 21 in the first region 26 located near the power supply unit 40 is made thicker than the line width W1 of the first directional wiring 21 in the second region 27 outside the first region 26. This increases the strength of the first directional wiring 21 near the power supply unit 40 (first region 26), where the current density is likely to be high and breakage is likely to occur after long-term use, thereby preventing breakage of the first directional wiring 21. Furthermore, during the process of fabricating the wiring substrate 10, the first directional wiring 21 near the power supply unit 40 is more likely to break than other portions. This increases the strength of the first direction wirings 21 in the vicinity of the power supply section 40 (first region 26), and prevents the first direction wirings 21 from breaking when the wiring board 10 is manufactured.

[0071] Furthermore, according to the present embodiment, wiring board 10 has substrate 11 having transparency and wiring pattern region 20 that is disposed on substrate 11 and includes a plurality of first directional wires 21, thereby ensuring the transparency of wiring board 10. As a result, when wiring board 10 is disposed on display 91, display 91 can be viewed through openings 23 of wiring pattern region 20, and visibility of display 91 is not hindered.

[0072] Moreover, according to this embodiment, the wiring pattern region 20 includes a plurality of second directional wirings 22 that connect a plurality of first directional wirings 21. This makes it possible to make the first directional wirings 21 less susceptible to breakage, and to suppress a decrease in the functionality of the first directional wirings 21.

[0073] Furthermore, according to this embodiment, the first region 26 of the wiring pattern region 20 is located at least between the second directional wiring 22 closest to the power supply section 40 and the power supply section 40. This allows the line width W3 of the first directional wiring 21 to be thickened near the connection section with the power supply section 40, thereby increasing the strength of the first directional wiring 21 and preventing breakage. Furthermore, since the region where the line width W3 of the first directional wiring 21 is thick does not become excessively long, there is no risk of impairing the transparency of the wiring board 10 as a whole.

[0074] Furthermore, according to the present embodiment, the length L4 of the first region 26 along the longitudinal direction (Y direction) of the wiring pattern region 20 is 0.1 mm or more and 0.5 mm or less. This allows the line width of the first directional wirings 21 to be thickened near the connection portion with the power supply section 40, thereby increasing the strength of the first directional wirings 21 and preventing breakage. Furthermore, since the region where the line width W3 of the first directional wirings 21 is thick does not become excessively long, there is no risk of impairing the transparency of the wiring board 10 as a whole.

[0075] Furthermore, according to the present embodiment, the line width W3 of the first directional wiring 21 in the first region 26 is 150% or more of the line width W1 of the first directional wiring 21 in the second region 27. This allows the line width of the first directional wiring 21 to be thickened near the connection portion with the power supply unit 40, thereby increasing the strength of the first directional wiring 21 and preventing breakage. Furthermore, since the region where the line width W3 of the first directional wiring 21 is thick does not become excessively long, there is no risk of impairing the transparency of the wiring board 10 as a whole.

[0076] Furthermore, according to the present embodiment, by increasing the line width W3 of the first directional wiring 21 in the first region 26, the resistance of the first directional wiring 21 present in the first region 26 becomes low. Adjusting the line width W3 of the first directional wiring 21 in the first region 26 makes it possible to control the resistance value (impedance). This facilitates impedance matching, which is particularly important in frequency regions such as millimeter waves and microwaves. That is, if the impedances of the first directional wiring 21 and the power supply unit 40 at the connection portion of the first directional wiring 21 are not approximately the same, reflections may occur, making it difficult for electromagnetic waves to propagate. In the present embodiment, by increasing the line width W3 of the first directional wiring 21 at the connection portion between the first directional wiring 21 and the power supply unit 40, it is possible to reduce the difference in impedance between the first directional wiring 21 and the power supply unit 40.

[0077] Furthermore, according to this embodiment, by increasing the line width W3 of the first directional wirings 21 in the first region 26, it is possible to improve the bending resistance of the first directional wirings 21. For example, as shown in FIG. 8, it is conceivable that the power supply unit 40 is disposed on the periphery of the display 91, and the first directional wirings 21 present in the first region 26 will be bent. In contrast, according to this embodiment, by increasing the line width W3 of the first directional wirings 21 in the first region 26, it is possible to prevent the first directional wirings 21 from being broken when bent.

[0078] 8, the wiring pattern region 20 is disposed on a display 91. The power supply unit 40 is disposed on a bezel (frame) 93 around the display 91, or is disposed by being folded on the bezel 93. The aperture ratio of the wiring pattern region 20 is, for example, in the range of 87% or more and less than 100%, whereas the aperture ratio of the power supply unit 40 is 0%. According to the present embodiment, by increasing the line width W3 of the first direction wiring 21 in the first region 26, a sudden change in the aperture ratio of the wiring pattern region 20 and the aperture ratio of the power supply unit 40 can be suppressed, and the wiring pattern region 20 can be made less visible.

[0079] (Modification of the first embodiment) Next, various modified examples of the wiring board according to this embodiment will be described with reference to Figures 9 to 14. Figures 9 to 14 are diagrams showing various modified examples of the wiring board. The modified examples shown in Figures 9 to 14 differ in the configuration of the wiring pattern region 20, but other configurations are substantially the same as the embodiment shown in Figures 1 to 7 described above. In Figures 9 to 14, the same parts as those in the embodiment shown in Figures 1 to 7 are given the same reference numerals, and detailed description thereof will be omitted.

[0080] (Modification 1 of the first embodiment) 9 shows a wiring board 10A according to a first modification of the present embodiment. In Fig. 9, the first region 26 of the first-directional wiring 21 is located only between the power supply section 40 and the second-directional wiring 22 that is closest to the power supply section 40 (located closest to the negative Y-direction side). In this case, it is possible to minimize a decrease in the transparency of the wiring board 10 as a whole while suppressing disconnection of the first-directional wiring 21.

[0081] (Modification 2 of the First Embodiment) FIG. 10 shows a wiring board 10B according to a second modification of the present embodiment. In FIG. 10, the line width W3 of the first region 26 is nonuniform along the longitudinal direction (Y direction) of the first-directional wirings 21. That is, the line width W3 of the first region 26 is widest near the power supply unit 40 and narrowest near the second region 27. In this case, the planar shape of the first-directional wirings 21 in the first region 26 has a shape in which the line width W3 gradually narrows as it moves away from the power supply unit 40. In FIG. 10, the planar shape of the first region 26 is a trapezoid or a triangle, and both sides of the first region 26 are straight. However, this is not a limitation, and both sides of the first region 26 may be curved. The configuration shown in FIG. 10 increases the strength of the connection portion of the first region 26 with the power supply unit 40, which has a higher current density, and suppresses disconnection of the first-directional wirings 21 at the connection portion with the power supply unit 40, while suppressing a decrease in the transparency of the wiring board 10 as a whole. Furthermore, by gradually widening the line width W3 of the first directional wiring 21 at the connection portion between the first directional wiring 21 and the power supply section 40, it becomes easier to perform impedance matching between the first directional wiring 21 and the power supply section 40, as described above.

[0082] (Third modification of the first embodiment) FIG. 11 shows a wiring board 10C according to a third modification of this embodiment. In FIG. 11, the line width W3 of the first region 26 is nonuniform along the longitudinal direction (Y direction) of the first directional wiring 21. That is, the line width W3 of the first region 26 is widest near the power supply unit 40 and narrowest near the second region 27. In this case, the line width W3 of the first region 26 gradually narrows from near the power supply unit 40 to near the second region 27. That is, the line width W3 between the power supply unit 40 and the second directional wiring 22 closest to the power supply unit 40 is the widest. Furthermore, the line width W3 between the second directional wiring 22 closest to the power supply unit 40 and the second directional wiring 22 second closest to the power supply unit 40 is the second widest. Furthermore, the line width W3 between the second directional wiring 22 second closest to the power supply unit 40 and the second directional wiring 22 third closest to the power supply unit 40 is the third widest. 11 , the strength of the connection portion with the power supply portion 40, which has a higher current density, in the first region 26 can be increased, and disconnection of the first directional wiring 21 at the connection portion with the power supply portion 40 can be suppressed, while suppressing a decrease in the transparency of the wiring substrate 10 as a whole.

[0083] (Fourth Modification of the First Embodiment) 12 shows a wiring board 10D according to a fourth modification of the present embodiment. In FIG. 12, the line width W of the first region 26 of the first direction wiring 21 located near the center of the wiring pattern region 20 in the width direction (X direction) is 3A is the line width W of the first region 26 of the first direction wiring 21 located near the edge of the wiring pattern region 20 in the width direction (X direction). 3B The line width of the first region 26 gradually increases from the first direction wirings 21 located near the center in the width direction toward the first direction wirings 21 located near the edge in the width direction.

[0084] Generally, while transmitting and receiving radio waves using the wiring pattern area 20, the value of the current flowing through the wiring pattern area 20 is not uniform in the width direction (X direction). Specifically, the value of the current flowing through the edge of the wiring pattern area 20 in the width direction is larger than the value of the current flowing through the center of the wiring pattern area 20 in the width direction. In contrast, according to the configuration shown in FIG. 12, the line width W 3A is the line width W at the edge of the wiring pattern area 20 in the width direction. 3B It is thinner than (W 3A <W 3B ) That is, the density of the first direction wirings 21 at the width direction edge portions where the current value is high is made higher than the density of the first direction wirings 21 at the width direction center portion where the current value is low. As a result, the current distribution is made uniform between the width direction center portion and width direction edge portions of the wiring pattern region 20 compared to when the mesh of the wiring pattern region 20 is uniform, and the characteristics (antenna characteristics, etc.) of the wiring pattern region 20 can be further improved.

[0085] (Fifth Modification of the First Embodiment) FIG. 13 shows a wiring board 10E according to a fifth modification of this embodiment. In FIG. 13, the line width W3 of the first region 26 is non-uniform along the longitudinal direction (Y direction) of the first directional wiring 21. That is, the line width W3 of the first region 26 is widest near the power supply unit 40 and narrowest near the second region 27. In this case, the planar shape of the first directional wiring 21 in the first region 26 is such that the line width W3 gradually narrows as it moves away from the power supply unit 40. In FIG. 13, the planar shape of the first directional wiring 21 in the first region 26 is a trapezoid or a triangle. The trapezoid or triangle is integrated with the trapezoid or triangle constituting the first directional wiring 21 adjacent in the X direction. This smooths the connection between the first directional wiring 21 and the power supply unit 40, facilitating impedance matching between the first directional wiring 21 and the power supply unit 40 as described above. Furthermore, a sudden change in the aperture ratio of the wiring pattern region 20 and the aperture ratio of the power supply portion 40 can be suppressed, making the wiring pattern region 20 less visible.

[0086] (Sixth Modification of the First Embodiment) FIG. 14 is an enlarged plan view showing a wiring board 10F according to a sixth modification of the present embodiment. In FIG. 14, the first-directional wirings 21 and the second-directional wirings 22 intersect at an angle, and each opening 23 is formed in a diamond shape in plan view. The first-directional wirings 21 and the second-directional wirings 22 are non-parallel to both the X direction and the Y direction, respectively. At a position adjacent to the power supply unit 40, a region 28 surrounded by the power supply unit 40, the first-directional wirings 21, and the second-directional wirings 22 is a non-opening. This region 28 is triangular in plan view. That is, the region 28 is filled with metal constituting the first-directional wirings 21, the second-directional wirings 22, and the power supply unit 40, and the substrate 11 is not exposed. This increases the strength of the first directional wiring 21 and the second directional wiring 22 in the vicinity of the power supply section 40 (first region 26), where the current density is likely to be high and breakage is likely to occur after long-term use, thereby making it possible to suppress breakage of the first directional wiring 21 and the second directional wiring 22.

[0087] All of the multiple regions 28 surrounded by the power supply unit 40, the first-directional wiring 21, and the second-directional wiring 22 may be non-openings, or only some of the multiple regions 28 may be non-openings. In the latter case, for example, the multiple regions 28 located near the center of the width direction (X direction) of the wiring pattern region 20 may be openings, and the multiple regions 28 located near the edges of the width direction (X direction) of the wiring pattern region 20 may be non-openings. In this case, as described above, the density of the metal parts at the edges of the wiring pattern region 20 in the width direction, where the current value is high, can be made higher than the density of the metal parts at the center of the wiring pattern region 20 in the width direction, where the current value is low. This makes the current distribution uniform between the center and edges of the wiring pattern region 20 in the width direction, thereby further improving the characteristics (antenna characteristics, etc.) of the wiring pattern region 20.

[0088] 1 to 14, the wiring pattern region 20 has been described as having an antenna function, but this is not limiting. The wiring pattern region 20 may have functions such as hovering (a function that allows a user to operate the display without directly touching it), fingerprint authentication, a heater, and noise reduction (shielding). Even in this case, by making the line width W3 of the first directional wiring 21 in the first region 26 thicker than the line width W1 of the first directional wiring 21 in the second region 27, it is possible to prevent breakage of the first directional wiring 21 without impairing the transparency of the wiring substrate 10.

[0089] (Second embodiment) Next, a second embodiment will be described with reference to Figs. 15 to 18. Figs. 15 to 18 are diagrams illustrating the second embodiment. The second embodiment illustrated in Figs. 15 to 18 differs mainly in the configuration of the power supply unit 40, and other configurations are substantially similar to those of the first embodiment illustrated in Figs. 1 to 14. In Figs. 15 to 18, the same parts as those illustrated in Figs. 1 to 14 are designated by the same reference numerals, and detailed description thereof will be omitted. The following description will focus on the differences from the first embodiment.

[0090] [Wiring board configuration] The configuration of the wiring board according to this embodiment will be described with reference to Figures 15 to 17. Figures 15 to 17 are diagrams showing the wiring board according to this embodiment.

[0091] 15, a wiring board 10 according to this embodiment is arranged on, for example, a display of an image display device. Such wiring board 10 includes a transparent substrate 11 and wiring pattern areas 20 arranged on the substrate 11. Furthermore, a power supply section 40 is electrically connected to each wiring pattern area 20.

[0092] In this embodiment, unlike the first embodiment, the first direction wiring 21 may have a uniform width overall. The area of ​​the openings 23 may be uniform within the wiring pattern region 20. In this case, there is no variation in the size of the openings 23 within the wiring pattern region 20, making it difficult to see the wiring pattern region 20 with the naked eye. The shape of the openings 23 is preferably the same shape and size within the wiring pattern region 20, but it does not have to be uniform across the entire surface and may vary depending on the location.

[0093] The cross-sectional shape of the first directional wiring 21 is substantially uniform throughout the longitudinal direction (Y direction) of the first directional wiring 21. The cross-sectional shape of the second directional wiring 22 is substantially uniform throughout the longitudinal direction (X direction) of the second directional wiring 22. However, this is not limiting, and in the present embodiment, as in the first embodiment, the line width of the first directional wiring 21 in the first region 26 located near the power supply unit 40 may be made thicker than the line width of the first directional wiring 21 in the second region 27. In addition, the configuration of the wiring pattern region 20 may be the same as in the first embodiment.

[0094] 15, the power supply unit 40 is electrically connected to each wiring pattern region 20. The power supply unit 40 is made of a conductive thin plate member having a substantially rectangular shape. The longitudinal direction of the power supply unit 40 is parallel to the X direction, and the lateral direction of the power supply unit 40 is parallel to the Y direction. The power supply unit 40 is disposed at the longitudinal end (the end on the negative side in the Y direction) of the substrate 11. The power supply unit 40 may be made of a metal material (including an alloy thereof) such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel. When the wiring substrate 10 is incorporated into an image display device 90 (see FIG. 18), the power supply unit 40 is electrically connected to a wireless communication circuit 92 of the image display device 90 via a power supply line 95. Note that the power supply unit 40 is provided on the surface of the substrate 11, but is not limited thereto. Part or all of the power supply unit 40 may be located outside the periphery of the substrate 11. In addition, in FIG. 15, a corresponding power supply section 40 is connected to each wiring pattern area 20, but this is not limited to this, and one power supply section 40 may be electrically connected to multiple wiring pattern areas 20.

[0095] As shown in FIG. 16, the plurality of first-directional wirings 21 are electrically connected to a power supply unit 40 on the negative Y-direction side. In this case, the power supply unit 40 is formed integrally with the wiring pattern region 20. A connection region 46 is formed on the opposite side (negative Y-direction side) of the power supply unit 40 from the wiring pattern region 20, electrically connecting to a power supply line 95 (described later). The length L6 of the power supply unit 40 in the longitudinal direction (X direction) may be 1 mm or more and 10 mm or less, and the length L5 of the power supply unit 40 in the lateral direction (Y direction) may be 0.5 mm or more and 3 mm or less. The thickness T3 (see FIG. 17) of the power supply unit 40 can be the same as the height H1 (see FIG. 3) of the first-directional wirings 21 and the height H2 (see FIG. 4) of the second-directional wirings 22, and can be selected, for example, from the range of 0.1 μm or more and 5.0 μm or less.

[0096] In this embodiment, the power supply unit 40 has a plurality of through holes 45. The through holes 45 are arranged in a lattice pattern in a plan view within the power supply unit 40. That is, the through holes 45 are arranged in multiple rows and columns within the plane of the power supply unit 40, with multiple through holes 45 arranged in each of the X and Y directions. The through holes 45 penetrate the power supply unit 40 in the thickness direction (Z direction), and the transparent substrate 11 is exposed through each through hole 45. In this case, the through holes 45 are arranged over substantially the entire plane of the power supply unit 40, but this is not a limitation. The through holes 45 are preferably arranged at least within the area covered by the protective layer 17 and within the connection area 46. This improves adhesion between the protective layer 17 and the power supply unit 40 and between the solder connecting the power supply line 95 and the power supply unit 40.

[0097] Each through hole 45 has a square shape in a plan view. The width (length of one side) W4 of each through hole 45 may be 50 μm or more and 500 μm or less. The planar shape of the through hole 45 is not limited to this, and may be a polygonal shape such as a circle, an ellipse, or a rectangle. The multiple through holes 45 are arranged at uniform intervals in the X and Y directions. Specifically, the pitch P3 of the multiple through holes 45 in the X direction may be, for example, 100 μm or more and 500 μm or less, and the pitch P4 of the multiple through holes 45 in the Y direction may be, for example, 100 μm or more and 500 μm or less. The multiple through holes 45 may be arranged at uniform intervals in only one of the X and Y directions. Furthermore, in this embodiment, the pitch P3 of the multiple through holes 45 in the X direction is equal to the pitch P4 of the multiple through holes 45 in the Y direction (P3=P4), but this is not limited thereto, and the pitch P3 and the pitch P4 may be different from each other.

[0098] 17, a protective layer 17 is formed on the surface of the substrate 11 so as to cover the wiring pattern region 20 and the power supply section 40. The protective layer 17 protects the wiring pattern region 20 and the power supply section 40, and may be formed over substantially the entire surface of the substrate 11. In addition, the configuration of the protective layer 17 may be the same as in the first embodiment.

[0099] As shown in FIG. 17 , the protective layer 17 has multiple protrusions 17a that protrude toward the substrate 11. The protrusions 17a have a shape that is a transcription of the through-holes 45 of the power supply unit 40. The tips of the protrusions 17a (the ends on the negative Z-direction side) contact the surface of the substrate 11. The protrusions 17a of the protective layer 17 penetrate into the through-holes 45 of the power supply unit 40 and harden, so that the protrusions 17a function as anchors. This allows the protective layer 17 to adhere strongly to the power supply unit 40, preventing the protective layer 17 from peeling off from the power supply unit 40. Note that the protective layer 17 may not cover the connection area 46 of the power supply unit 40 to make it easier to connect the power supply line 95 to the power supply unit 40.

[0100] [Method of manufacturing wiring board] The wiring board according to this embodiment can be manufactured in a manner substantially similar to that of the first embodiment (FIGS. 6(a)-(i)). In this embodiment, the power supply unit 40 having the plurality of through holes 45 may be formed by a portion of the conductor 55 when the conductive layer 51 on the surface of the substrate 11 is removed (see FIG. 6(h)). Alternatively, a flat power supply unit 40 having the plurality of through holes 45 may be separately prepared and electrically connected to the wiring pattern area 20. Thereafter, when the protective layer 17 is formed to cover the wiring pattern area 20 and the power supply unit 40 on the substrate 11 (see FIG. 6(i)), a portion of the protective layer 17 penetrates into the plurality of through holes 45 and hardens, forming protrusions 17a that are firmly bonded to the power supply unit 40 (see FIG. 17).

[0101] [Operation of this embodiment] Next, the operation of the wiring board having such a configuration will be described.

[0102] As shown in FIG. 18 , the wiring board 10 is incorporated into an image display device 90 having a display 91. The wiring board 10 is disposed on the display 91. Examples of such image display devices 90 include mobile terminal devices such as smartphones and tablets. The wiring pattern region 20 of the wiring board 10 is electrically connected to a wireless communication circuit 92 of the image display device 90 via a power supply unit 40 and a power supply line 95. In this way, radio waves of a predetermined frequency can be transmitted and received via the wiring pattern region 20, and communication can be performed using the image display device 90.

[0103] Generally, power supply unit 40 contacts protective layer 17 over a larger area than first-directional wiring 21 and second-directional wiring 22. However, because metal power supply unit 40 and resin protective layer 17 are made of different materials, their adhesion is not necessarily strong. For this reason, if a force is applied to wiring substrate 10 in a bending direction while image display device 90 is in use, protective layer 17 may peel off from power supply unit 40, and this may serve as a starting point for protective layer 17 to peel off from the entire surface of substrate 11.

[0104] In contrast, according to the present embodiment, power supply unit 40 has a plurality of through holes 45 in its surface, and therefore parts of protective layer 17 (protrusions 17a) that have entered through holes 45 act as anchors, firmly bonding power supply unit 40. This makes it possible to prevent protective layer 17 from peeling off power supply unit 40.

[0105] Furthermore, according to this embodiment, solder for connecting the power feed line 95 to the power supply unit 40 can be introduced into the multiple through holes 45 of the power supply unit 40. As a result, part of the solder that has entered the through holes 45 serves as an anchor and is connected to the power supply unit 40. This allows the power feed line 95 to be firmly connected to the power supply unit 40. Furthermore, since the power supply unit 40 has multiple through holes 45, the flow of solder can be blocked to prevent the solder from spreading more than necessary.

[0106] Furthermore, according to the present embodiment, wiring board 10 has substrate 11 having transparency and wiring pattern region 20 that is disposed on substrate 11 and includes a plurality of first directional wires 21, thereby ensuring the transparency of wiring board 10. As a result, when wiring board 10 is disposed on display 91, display 91 can be viewed through openings 23 of wiring pattern region 20, and visibility of display 91 is not hindered.

[0107] Furthermore, according to this embodiment, the wiring pattern region 20 includes a plurality of second directional wirings 22 that connect a plurality of first directional wirings 21. This makes it possible to make the first directional wirings 21 less susceptible to breakage, and to suppress a decrease in the functionality of the first directional wirings 21.

[0108] Furthermore, according to this embodiment, the protective layer 17 is formed so as to cover the wiring pattern area 20 and the power supply part 40. This makes it possible to protect the wiring pattern area 20 and the power supply part 40 from external impacts and the like.

[0109] Furthermore, according to the present embodiment, the plurality of through holes 45 are arranged in multiple rows and multiple stages within the plane of the power supply unit 40. This allows the protective layer 17 and the through holes 45 to be connected over a wide area of ​​the power supply unit 40.

[0110] Furthermore, according to this embodiment, the plurality of through holes 45 are arranged at uniform intervals in at least one direction, which allows the protective layer 17 and the through holes 45 to be connected with approximately uniform strength within the plane.

[0111] Furthermore, power supply unit 40 may be joined to a circuit board of image display device 90 using, for example, a joint (not shown). In this case, power supply unit 40 has a plurality of through holes 45, which increases the surface area of ​​power supply unit 40 and improves adhesion between power supply unit 40 and the joint. An example of such a joint is an anisotropic conductive film (ACF). The circuit board may also be a board made of a flexible material such as an FPC (Flexible Printed Circuit).

[0112] Recently, development of mobile terminal devices for fifth-generation communication, i.e., 5G (Generation), has been progressing. When the wiring pattern area 20 of the wiring board 10 is used as, for example, a 5G antenna (especially a millimeter wave antenna), the radio waves (millimeter waves) transmitted and received by the wiring pattern area 20 have a higher frequency than the radio waves transmitted and received by, for example, a 4G antenna.

[0113] Generally, when AC current is passed through wiring, the higher the frequency, the more difficult it becomes for the current to flow through the center of the wiring, and the more the current flows on the surface of the wiring. This phenomenon in which current flows only on the surface when AC current is passed through wiring is called the skin effect. Furthermore, skin depth refers to the depth from the surface of the wiring where the current attenuates by 1 / e (approximately 0.37) times compared to the current on the surface of the wiring, where it flows most easily. This skin depth δ can generally be calculated using the following formula.

[0114]

number

[0115] In the above formula, ω is the angular frequency (=2πf), μ is the magnetic permeability (4π×10 in a vacuum) -7 [H / m]), and σ is the conductivity of the conductor that makes up the wiring (5.8×10 for copper). 7The skin depth δ of copper wiring is approximately 2.3 μm when the frequency is 0.8 GHz, approximately 1.3 μm when the frequency is 2.4 GHz, approximately 1.0 μm when the frequency is 4.4 GHz, and approximately 0.85 μm when the frequency is 6 GHz. Furthermore, the radio waves (millimeter waves) transmitted and received by 5G antennas are higher frequency (28 GHz to 39 GHz) than the radio waves transmitted and received by 4G antennas, and when the current frequency is 28 GHz to 39 GHz, for example, δ is approximately 0.3 μm to 0.4 μm.

[0116] Thus, current flows from the surface of the wiring at a depth equivalent to the skin depth δ. Therefore, particularly when the radio waves transmitted and received by the wiring pattern region 20 are high-frequency (e.g., 28 GHz to 39 GHz), the skin depth δ is small, and therefore the surfaces of the first-directional wiring 21 and the second-directional wiring 22 must be smooth. In this embodiment, the wiring pattern region 20 and the power supply unit 40 are fabricated simultaneously, so the surfaces of the wiring pattern region 20 and the power supply unit 40 are also smooth. On the other hand, since the power supply unit 40 is connected to a solder or a joint (ACF), it is necessary to improve the adhesion between the power supply unit 40 and the solder or the joint (ACF). Therefore, in this embodiment, by forming a plurality of through holes 45 in the power supply unit 40 and increasing the surface area of ​​the power supply unit 40, the adhesion between the power supply unit 40 and the solder or the joint (ACF) can be improved.

[0117] (Modification of the second embodiment) Next, various modified examples of the wiring board according to this embodiment will be described with reference to Figs. 19 to 22. Figs. 19 to 22 are diagrams showing various modified examples of the wiring board. The modified examples shown in Figs. 19 to 22 differ in the configuration of the power supply section 40 or the wiring pattern region 20, but other configurations are substantially the same as the embodiment shown in Figs. 15 to 18 described above. In Figs. 19 to 22, the same parts as those shown in Figs. 15 to 18 are given the same reference numerals, and detailed description thereof will be omitted.

[0118] (Modification 1 of the second embodiment) 19(a)-(c) show a wiring board 10G according to a first modification of the present embodiment. In the above-described embodiment, the plurality of through holes 45 are each square in plan view and are arranged in a lattice pattern within the plane of the power supply unit 40. However, this is not limiting. As shown in FIG. 19(a), the plurality of through holes 45 may each be square in plan view and arranged in a staggered pattern within the plane of the power supply unit 40. As shown in FIG. 19(b), the plurality of through holes 45 may each be circular in plan view and arranged in a lattice pattern within the plane of the power supply unit 40. As shown in FIG. 19(c), the plurality of through holes 45 may each be diamond-shaped in plan view and arranged in a lattice pattern within the plane of the power supply unit 40. Alternatively, each through hole 45 may be polygonal, such as a parallelogram, trapezoid, triangle, or hexagon, or may be elliptical in plan view.

[0119] (Modification 2 of the second embodiment) 20(a)-(b) show a wiring board 10H according to a second modification of the present embodiment. As shown in FIGS. 20(a)-(b), the area and pitch of the plurality of through holes 45 may be different in a region closer to the wiring pattern region 20 and a region farther from the wiring pattern region 20. For example, as shown in FIG. 20(a), the area of ​​the plurality of through holes 45 (width W4 of the through holes 45) may be larger in a region closer to the wiring pattern region 20 and gradually decrease as the distance from the wiring pattern region 20 increases. Alternatively, as shown in FIG. 20(b), the pitch P4 of the plurality of through holes 45 may be smaller in a region closer to the wiring pattern region 20 and gradually increase as the distance from the wiring pattern region 20 increases. This results in a lower resistance value of the power supply unit 40 in a region farther from the wiring pattern region 20 than in a region closer to the wiring pattern region 20. In this way, the resistance value (impedance) can be controlled by adjusting the area and pitch of the plurality of through holes 45. This facilitates impedance matching, which is particularly important in frequency regions such as millimeter waves and microwaves. In this embodiment, it is possible to reduce the difference in impedance between the wiring pattern area 20 and the feeder line 95 at the feeder section 40 located at the connection between the wiring pattern area 20 and the feeder line 95.

[0120] (Modification 3 of the second embodiment) 21 shows a wiring board 10I according to a third modification of the present embodiment. As shown in FIG. 21, similarly to the first embodiment, the line width W3 of the first directional wirings 21 in the first region 26 may be made larger than the line width W1 of the first directional wirings 21 in the second region 27. In this case, the resistance value (impedance) of the first directional wirings 21 can be controlled by adjusting the line width W3 of the first directional wirings 21 in the first region 26, and the resistance value (impedance) of the power supply unit 40 can be controlled by adjusting the number and shape of the plurality of through holes 45. This makes it easier to perform impedance matching between the first directional wirings 21 and the power supply unit 40.

[0121] (Fourth modification of the second embodiment) FIG. 22 illustrates a wiring substrate 10J according to a fourth modification of the present embodiment. As illustrated in FIG. 22, the power supply unit 40 may have a plurality of non-through recesses 47 instead of through holes 45. The non-through recesses 47 are arranged in a lattice pattern in a plan view within the power supply unit 40. That is, the non-through recesses 47 are arranged in multiple rows and columns within the plane of the power supply unit 40, with multiple non-through recesses 47 arranged in each of the X and Y directions. The non-through recesses 47 do not penetrate the power supply unit 40 in the thickness direction (Z direction). The depth D1 of the non-through recesses 47 can be selected, for example, from 0.1 μm to 3.0 μm. To form the non-through recesses 47, in the step of removing the conductive layer 51 on the surface of the substrate 11 (see FIG. 6(h)), the power supply unit 40 is covered with a resist or the like, and the conductive layer 51 within the power supply unit 40 remains, thereby forming the non-through recesses 47 in the power supply unit 40. In addition, the planar shape and arrangement of the non-through recesses 47 can be substantially the same as those of the through holes 45 described above.

[0122] 15 to 22, the wiring pattern area 20 has been described as having an antenna function, but this is not limiting. The wiring pattern area 20 may have other functions, such as hovering (a function that allows the user to operate the display without directly touching it), fingerprint authentication, a heater, noise reduction (shielding), etc.

[0123] It is also possible to combine the multiple components disclosed in the above embodiments and modifications as needed, or to delete some of the components disclosed in the above embodiments and modifications.

Claims

1. A wiring board, A substrate; a wiring pattern area disposed on the substrate, the wiring pattern area including a plurality of first directional wirings and a plurality of second directional wirings connecting the plurality of first directional wirings; a power supply section electrically connected to the plurality of first direction wirings in the wiring pattern area, the power supply portion has a plurality of through holes or a plurality of non-through recesses, each of the plurality of first direction wirings has a first region located near the power supply portion and a second region other than the first region; a line width of the first directional wiring in the first region is larger than a line width of the first directional wiring in the second region; a length of the first region along the longitudinal direction of the wiring pattern region is 0.1 mm or more and 0.5 mm or less; A wiring board, wherein the line width of the second directional wiring located in the first region is the same as that of the second directional wiring located in the second region.

2. The wiring board according to claim 1 , wherein the plurality of through holes or the plurality of non-through recesses are arranged in a plurality of rows and columns within a plane of the power supply portion.

3. The wiring board according to claim 1 , wherein the plurality of through holes or the plurality of non-through recesses are arranged at uniform intervals from one another in at least one direction.

4. The wiring board according to claim 1 , wherein each of the through holes or non-through recesses has a width of 50 μm or more and 500 μm or less.

5. The wiring board according to claim 1 , wherein the pitch of the plurality of through holes or the plurality of non-through recesses is 100 μm or more and 500 μm or less.

6. The wiring board according to claim 1 , further comprising a protective layer formed on the board so as to cover the wiring pattern area and the power supply portion.

7. The wiring board according to claim 1 , wherein the line width of the first direction wiring is in the range of 0.1 μm to 5.0 μm.

8. 2. The wiring board according to claim 1, wherein the wiring pattern region functions as an antenna.

9. 2. The wiring board according to claim 1, wherein the area or pitch of the plurality of through holes or the plurality of non-through recesses differs between an area close to the wiring pattern area and an area far from the wiring pattern area.

10. A method for manufacturing a wiring substrate, providing a substrate; forming, on the substrate, a wiring pattern area including a plurality of first directional wirings and a plurality of second directional wirings connecting the plurality of first directional wirings, and a power supply unit electrically connected to the plurality of first directional wirings in the wiring pattern area; the power supply portion has a plurality of through holes or non-through recesses, each of the plurality of first direction wirings has a first region located near the power supply portion and a second region other than the first region; a line width of the first directional wiring in the first region is larger than a line width of the first directional wiring in the second region; a length of the first region along the longitudinal direction of the wiring pattern region is 0.1 mm or more and 0.5 mm or less; A method for manufacturing a wiring substrate, wherein the line width of the second direction wiring located in the first region is the same as that of the second direction wiring located in the second region.

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