Wiring substrate and method for manufacturing wiring substrate

Abstract

The invention provides a wiring substrate and a method for manufacturing the wiring substrate. A wiring substrate (10) is provided with: a transparent substrate (11); a wiring pattern region (20) that is disposed on the substrate (11) and includes a plurality of first direction wirings (21); and a power supply unit (40) that is electrically connected to the plurality of first direction wirings (21) in the wiring pattern region (20). The first direction wiring (21) has a first region (26) located in the vicinity of the power supply unit (40) and a second region (27) other than the first region (26). The line width (W3) of the first direction wiring (21) in the first region (26) is larger than the line width (W1) of the first direction wiring (21) in the second region (27).

Description

[0001] This application is a divisional application of the Chinese invention patent application with an application date of April 21, 2020, an invention name of “Wiring Substrate and Method for Manufacturing Wiring Substrate”, and an application number of 202080033584.6 (PCT / JP2020 / 017139). Technical Field

[0002] Embodiments of the present disclosure relate to a wiring board and a method for manufacturing the wiring board. Background Art

[0003] At present, the high-function, miniaturization, thinning and lightness of portable terminal devices such as smartphones and tablet computers are constantly developing. In order to use multiple communication frequency bands, these portable terminal devices require multiple antennas corresponding to the communication frequency bands. For example, the portable terminal device is equipped with multiple antennas such as telephone antennas, WiFi (Wireless Fidelity) antennas, 3G (Generation: third generation digital communication) antennas, 4G (Generation: fourth generation digital communication) antennas, LTE (Long Term Evolution: long-term evolution) antennas, Bluetooth (Bluetooth, registered trademark) antennas, NFC (NearField Communication: near-field wireless communication) antennas. However, with the miniaturization of portable terminal devices, the mounting space for antennas is limited, thereby limiting the freedom of antenna design. In addition, since the antenna is built into a limited space, it may not be able to meet the radio wave sensitivity.

[0004] Therefore, a film antenna that can be mounted on the display area of ​​a portable terminal device has been developed. The film antenna is a transparent antenna having an antenna pattern formed on a transparent substrate, wherein the antenna pattern is formed by a grid-shaped conductive mesh layer, and the grid-shaped conductive mesh layer is composed of a conductor portion as a forming portion of an opaque conductive layer and a plurality of opening portions as a non-forming portion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-66610

[0008] Patent Document 2: Japanese Patent No. 5636735

[0009] Patent Document 3: Japanese Patent No. 5695947

[0010] However, in the conventional film antenna, the current density in the area near the power supply part in the conductor mesh layer tends to be higher than in other areas. Therefore, when the film antenna is used for a long time, the wiring is more likely to be disconnected in the area near the power supply part than in other areas of the conductor mesh layer.

[0011] The present embodiment provides a wiring board and a method for manufacturing the wiring board that can suppress disconnection of wiring in a wiring pattern region near a power supply portion.

[0012] In addition, in the film antenna, it is preferred to cover with a protective layer to protect the conductor mesh layer and the power supply part. However, generally speaking, the power supply part for supplying power to the conductor mesh layer is composed of a metal plate-like component with no gaps and uniformity on the entire surface, so the protective layer covering the power supply part and the power supply part may be peeled off.

[0013] The present embodiment provides a wiring board and a method for manufacturing the wiring board in which the protective layer and the power supply portion can be prevented from being peeled off from each other. Summary of the invention

[0014] The wiring substrate of this embodiment is a wiring substrate comprising: a substrate which is transparent; a wiring pattern area which is arranged on the substrate and includes a plurality of first direction wirings; and a power supply portion which is electrically connected to the plurality of first direction wirings in the wiring pattern area, the first direction wiring having a first area located near the power supply portion and a second area excluding the first area, the line width of the first direction wiring in the first area being thicker than the line width of the first direction wiring in the second area.

[0015] In the wiring substrate of this embodiment, the wiring pattern region may include a plurality of second-direction wirings connecting the plurality of first-direction wirings, and the first region may be located at least between the second-direction wirings closest to the power feeding portion and the power feeding portion.

[0016] In the wiring substrate of the present embodiment, a planar shape of the first-direction wiring in the first region may be a shape in which a line width gradually becomes narrower as it becomes farther away from the power supply portion.

[0017] In the wiring substrate of this embodiment, the line width of the first direction wiring in the first region near the widthwise center of the wiring pattern region may be thinner than the line width of the first direction wiring in the first region near the widthwise edge of the wiring pattern region.

[0018] In the wiring substrate of the present embodiment, a length of the first region along the longitudinal direction of the wiring pattern region may be greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

[0019] In the wiring substrate of the present embodiment, the line width of the first-direction wiring in the first region may be 150% or more of the line width of the first-direction wiring in the second region.

[0020] In the wiring substrate of the present embodiment, the line width of the first-direction wiring in the second region may be in a range of 0.1 μm to 5.0 μm.

[0021] The wiring substrate of this embodiment is a wiring substrate comprising: a substrate which is transparent; a wiring pattern area which is arranged on the substrate and includes a plurality of first-direction wirings and a plurality of second-direction wirings; and a power supply portion which is electrically connected to the plurality of first-direction wirings and the plurality of second-direction wirings in the wiring pattern area, and the area surrounded by the power supply portion, the first-direction wirings and the second-direction wirings is a non-opening portion.

[0022] The manufacturing method of the wiring substrate of the present embodiment is a manufacturing method of the wiring substrate, which comprises the following steps: preparing a transparent substrate; and forming a wiring pattern area and a power supply portion on the substrate, wherein the wiring pattern area includes a plurality of first direction wirings, the power supply portion is electrically connected to the plurality of first direction wirings in the wiring pattern area, the first direction wiring has a first area located near the power supply portion and a second area excluding the first area, and the line width of the first direction wiring in the first area is thicker than the line width of the first direction wiring in the second area.

[0023] According to the embodiment of the present disclosure, it is possible to suppress the occurrence of disconnection of wiring in the wiring pattern region near the power supply portion.

[0024] The wiring substrate of this embodiment is a wiring substrate comprising: a substrate having transparency; a wiring pattern area arranged on the substrate and including a plurality of wirings; and a power supply portion electrically connected to the plurality of wirings in the wiring pattern area, the power supply portion having a plurality of through holes or a plurality of non-through recesses.

[0025] In the wiring substrate of the present embodiment, the plurality of through holes or the plurality of non-through recessed portions may be arranged in a plurality of stages and in a plurality of rows within a plane of the power supply portion.

[0026] In the wiring substrate of the present embodiment, the plurality of through holes or the plurality of non-through recessed portions may be arranged at uniform intervals from each other in at least one direction.

[0027] In the wiring substrate of 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.

[0028] In the wiring substrate of the present embodiment, a pitch between the plurality of through holes or the plurality of non-through recessed portions may be greater than or equal to 100 μm and less than or equal to 500 μm.

[0029] In the wiring substrate of the present embodiment, a protective layer may be formed on the substrate so as to cover the wiring pattern region and the power supply portion.

[0030] In the wiring substrate of the present embodiment, the line width of the wiring may be in a range of 0.1 μm to 5.0 μm.

[0031] In the wiring substrate of the present embodiment, the wiring pattern region may function as an antenna.

[0032] In the wiring substrate of the present embodiment, the areas or pitches of the plurality of through holes or the plurality of non-through recesses may be different between a region close to the wiring pattern region and a region far from the wiring pattern region.

[0033] The manufacturing method of the wiring substrate of the present embodiment is a manufacturing method of the wiring substrate, which comprises the following steps: preparing a transparent substrate; and forming a wiring pattern area and a power supply portion on the substrate, wherein the wiring pattern area includes a plurality of wirings, the power supply portion is electrically connected to the plurality of wirings in the wiring pattern area, and the power supply portion has a plurality of through holes or a plurality of non-through recesses.

[0034] According to the embodiment of the present disclosure, it is possible to suppress the protective layer and the power feeding portion from being peeled off from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a plan view showing the wiring board according to the first embodiment.

[0036] Figure 2 is an enlarged plan view showing a wiring substrate according to the first embodiment ( Figure 1 (enlarged view of part II).

[0037] Figure 3 is a cross-sectional view showing a wiring substrate according to the first embodiment (along the Figure 2 sectional view along line III-III).

[0038] Figure 4 is a cross-sectional view showing a wiring substrate according to the first embodiment (along the Figure 2 sectional view along line IV-IV).

[0039] Figure 5 is an enlarged plan view showing a wiring substrate according to the first embodiment ( Figure 1 (enlarged view of the V part).

[0040] Figure 6 (a) to (i) are cross-sectional views illustrating the method for manufacturing the wiring board according to the first embodiment.

[0041] Figure 7 It is a plan view showing the image display device according to the first embodiment.

[0042] Figure 8 It is a partially enlarged plan view showing an image display device according to a modification of the first embodiment.

[0043] Fig. 9 This is an enlarged plan view showing a wiring board according to Modification 1 of the first embodiment.

[0044] Fig.10 It is an enlarged plan view showing a wiring board according to Modification 2 of the first embodiment.

[0045] Fig.11 This is an enlarged plan view showing a wiring board according to Modification 3 of the first embodiment.

[0046] Fig.12 It is an enlarged plan view showing a wiring board according to Modification 4 of the first embodiment.

[0047] Fig.13 It is an enlarged plan view showing a wiring board according to Modification 5 of the first embodiment.

[0048] Fig.14 It is an enlarged plan view showing a wiring board according to Modification 6 of the first embodiment.

[0049] Fig.15 It is a plan view showing a wiring board according to the second embodiment.

[0050] Fig.16 is an enlarged plan view showing a wiring substrate according to the second embodiment ( Fig.15 (enlarged view of part XVI of FIG. 1 ).

[0051] Fig.17 is a cross-sectional view showing a power supply portion of a wiring substrate according to a second embodiment (along the Fig.16 sectional view along line XVII-XVII).

[0052] Fig.18 It is a plan view showing an image display device according to the second embodiment.

[0053] Fig.19 (a) to (c) are enlarged plan views showing a wiring board according to Modification 1 of the second embodiment.

[0054] Fig. 20(a)-(b) are enlarged plan views showing a wiring board according to a second modification of the second embodiment.

[0055] Fig.21 It is an enlarged plan view showing a wiring board according to Modification 3 of the second embodiment.

[0056] Fig. 22 It 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

[0057] The figures shown below are schematically shown. Therefore, in order to facilitate understanding, the size and shape of each part are appropriately exaggerated. In addition, the implementation can be appropriately changed without departing from the technical idea. In addition, in the figures shown below, the same parts are marked with the same reference numerals, and a part of the detailed description is sometimes omitted. In addition, the numerical values ​​and material names such as the dimensions of each component recorded in this specification are examples of implementation methods, are not limited to this, and can be appropriately selected for use. In this specification, for terms that determine shapes and geometric conditions, such as parallel, orthogonal, vertical, etc., in addition to strict definitions, substantially the same state is also included.

[0058] In addition, in the following embodiments, the "X direction" is a direction parallel to one side of the substrate. The "Y direction" is a direction perpendicular to the X direction and parallel to the other side of the substrate. The "Z direction" is a direction perpendicular to both the X direction and the Y direction and parallel to the thickness direction of the wiring substrate. In addition, the "front side" refers to the surface on the positive side of the Z direction, and refers to the surface on which the wiring is provided to the substrate. The "back side" refers to the surface on the negative side of the Z direction, and refers to the surface on the opposite side of the surface on which the wiring is provided to the substrate.

[0059] (First embodiment)

[0060] according to Figures 1 to 15 , the first embodiment is described. Figures 1 to 15 It is a figure which shows the 1st embodiment.

[0061] [Structure of wiring board]

[0062] Reference Figures 1 to 5 , the structure of the wiring substrate of this embodiment is described. Figures 1 to 5 It is a diagram showing a wiring board according to this embodiment.

[0063] like Figure 1 As shown, the wiring substrate 10 of this embodiment is disposed on a display of an image display device, for example. Such a wiring substrate 10 includes: a transparent substrate 11; and a wiring pattern area 20 disposed on the substrate 11. In addition, a power supply unit 40 is electrically connected to the wiring pattern area 20.

[0064] Among them, when viewed from above, the substrate 11 is in a roughly rectangular shape, with its long side parallel to the Y direction and its short side parallel to the X direction. The substrate 11 is transparent and is roughly flat, and its thickness is roughly uniform as a whole. The length L1 in the long side direction (Y direction) of the substrate 11 can be selected, for example, within the range of 100 mm to 200 mm, and the length L2 in the short side direction (X direction) of the substrate 11 can be selected, for example, within the range of 50 mm to 100 mm. In addition, the corners of the substrate 11 can also be rounded.

[0065] The material of the substrate 11 can be any material as long as it has transparency and electrical insulation in the visible light region. In the present embodiment, the material of the substrate 11 is polyethylene terephthalate, but it is not limited to this. As the material of the substrate 11, it is preferred to use 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, or a polyolefin resin such as a cycloolefin polymer, a cellulose resin material such as triacetyl cellulose, etc. In addition, as the material of the substrate 11, glass, ceramics, etc. can also be appropriately selected according to the application. In addition, an example in which the substrate 11 is composed of one layer is shown, but it is not limited to this, and it can also be a structure in which multiple substrates or layers are stacked together. In addition, the substrate 11 can be in a film shape or in a plate shape. Therefore, the thickness of the substrate 11 is not particularly limited and can be appropriately selected according to the application, but as an example, the thickness (Z direction) T1 of the substrate 11 (refer to Figure 3 ) can be set, for example, in the range of 10 μm to 200 μm.

[0066] In this embodiment, the wiring pattern region 20 is composed of an antenna pattern region having a function as an antenna. Figure 1 In the embodiment, a plurality of (three) wiring pattern regions 20 are formed on the substrate 11, each corresponding to a different frequency band. That is, the length (length in the Y direction) L of the plurality of wiring pattern regions 20 is a The length L of the wiring pattern region 20 is different from each other and each has a length corresponding to a specific frequency band. a The longer the wiring substrate 10 is, for example, arranged on a display 91 of an image display device 90 (see the following description). Figure 7 ), each wiring pattern area 20 can correspond to any 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.

[0067] Each wiring pattern region 20 is substantially rectangular in shape when viewed from above. The long side direction of each wiring pattern region 20 is parallel to the Y direction, and the short side direction (width direction) thereof is parallel to the X direction. The length L of each wiring pattern region 20 in the long side direction (Y direction) is a For example, the width W of each wiring pattern region 20 in the short side direction (width direction) can be selected within a range of 3 mm to 100 mm. a For example, the diameter can be selected within a range of 1 mm to 10 mm.

[0068] In the wiring pattern area 20, the metal wires are formed in a lattice shape or a mesh shape, and have a repeated pattern in the X direction and the Y direction. That is, the wiring pattern area 20 has a pattern shape composed of a portion extending in the X direction (the second direction wiring 22) and a portion extending in the Y direction (the first direction wiring 21).

[0069] like Figure 2 As shown, each wiring pattern area 20 includes: a plurality of first-direction wirings (antenna wirings) 21 having a function as an antenna; and a plurality of second-direction wirings (antenna connection wirings) 22 connecting the plurality of first-direction wirings 21. Specifically, the plurality of first-direction wirings 21 and the plurality of second-direction wirings 22 are integrated as a whole to form a lattice shape or a mesh shape. Each first-direction wiring 21 extends in a direction corresponding to the frequency band of the antenna (long side direction, Y direction), and each second-direction wiring 22 extends in a direction perpendicular to the first-direction wiring 21 (width direction, X direction). The first-direction wiring 21 has a length L corresponding to a specified frequency band. a (The length of the wiring pattern area 20 described above is referred to as Figure 1 On the other hand, the second direction wiring 22 connects the first direction wirings 21 to each other, thereby preventing the following undesirable situations: the first direction wiring 21 is disconnected or the first direction wiring 21 and the power supply unit 40 become disconnected electrically.

[0070] In each wiring pattern area 20, a plurality of openings 23 are formed by being surrounded by adjacent first direction wirings 21 and adjacent second direction wirings 22. When viewed from above, each opening 23 is approximately rectangular or square. The area of ​​the opening 23 is uniform at least in the second area 27 described later. In addition, the transparent substrate 11 is exposed from each opening 23. Therefore, by increasing the total area of ​​the openings 23 per unit area of ​​the wiring pattern area 20, the transparency of the wiring substrate 10 as a whole can be improved.

[0071] like Figure 2As shown, a plurality of first direction wirings 21 are arranged at intervals (pitch P1) from each other in the width direction (X direction) of the wiring pattern area 20. In this case, a plurality of first direction wirings 21 are arranged at uniform intervals from each other along the width direction (X direction) of the wiring pattern area 20. In addition, the first direction wirings 21 and the second direction wirings 22 are arranged at equal intervals from each other. That is, a plurality of first direction wirings 21 are arranged at equal intervals from each other, and their pitch P1 can be set, for example, in the range of 0.01 mm or more and 1 mm or less. In addition, a plurality of second direction wirings 22 are arranged at equal intervals from each other, and their pitch P2 can be set, for example, in the range of 0.01 mm or more and 1 mm or less. In this way, a plurality of first direction wirings 21 and a plurality of second direction wirings 22 are arranged at equal intervals, respectively, thereby, at least in the second area 27 described later, the size of the opening 23 has no deviation, and the wiring pattern area 20 can be made difficult to see with the naked eye. In addition, at least in the second area 27 described later, the spacing P1 of the first direction wiring 21 is equal to the spacing P2 of the second direction wiring 22. Therefore, in the second area 27, when viewed from above, each opening 23 is roughly square in shape, and the transparent substrate 11 is exposed from each opening 23. In this way, by expanding the area of ​​each opening 23, the transparency of the wiring substrate 10 as a whole can be improved. In addition, the length L3 of one side of each opening 23 can be set to a range of more than 0.01 mm and less than 1 mm, for example. In addition, each first direction wiring 21 and each second direction wiring 22 are perpendicular to each other, but are not limited to this, and can also cross each other at an acute angle or an obtuse angle. In addition, the shape of the opening 23 is preferably set to the same shape and the same size at least in the second area 27 described later, but it can also be changed according to the location, etc., so as to be uneven on the entire surface.

[0072] like Figure 3 As shown, the cross section (X-direction cross section) perpendicular to the long side direction of each first direction wiring 21 is substantially rectangular or substantially square. The cross-sectional shape of the first direction wiring 21 is different between the first region 26 and the second region 27 described later. In the first region 26 or the second region 27, the cross-sectional shape of the first direction wiring 21 is substantially uniform along the long side direction (Y-direction) of the first direction wiring 21.

[0073] In addition, if Figure 4As shown, the shape of the cross section (Y-direction cross section) perpendicular to the long side direction of each second direction wiring 22 is a substantially rectangular shape or a substantially square shape, which is substantially the same as the shape of the cross section (X-direction cross section) of the first direction wiring 21 in the second region 27 described above. In this case, the cross-sectional shape of the second direction wiring 22 is substantially uniform along the long side direction (X-direction) of the second direction wiring 22. The cross-sectional shape of the first direction wiring 21 and the second direction wiring 22 may not necessarily be a substantially rectangular shape or a substantially square shape, and may be, for example, a substantially trapezoidal shape in which the front side (Z-direction positive side) is narrower than the back side (Z-direction negative side), or a shape in which the side surfaces on both sides of the long side direction are curved.

[0074] In this embodiment, the line width W1 (length in the X direction, see Figure 3 ) and the line width W2 (length in the Y direction, see Figure 4 ) is not particularly limited and can be appropriately selected according to the application. For example, the line width W1 of the first direction wiring 21 can be selected within the range of 0.1 μm to 5.0 μm, and the line width W2 of the second direction wiring 22 can be selected within the range of 0.1 μm to 5.0 μm. In addition, the height H1 (length in the Z direction, see Figure 3 ) and the height H2 of the second direction wiring 22 (the length in the Z direction, see Figure 4 ) is not particularly limited and can be appropriately selected depending on the intended use, and can be selected, for example, within the range of 0.1 μm to 5.0 μm.

[0075] like Figure 5 As shown, the plurality of first-direction wirings 21 are electrically connected to the power supply portion 40 on the negative side in the Y direction. The plurality of first-direction wirings 21 each have a first region 26 located near the power supply portion 40 and a second region 27 excluding the first region 26. The first region 26 is a region located on the negative side in the Y direction in the first-direction wiring 21, and is a region including a connection portion connected to the power supply portion 40. In addition, the second region 27 is a region located on the positive side in the Y direction in the first-direction wiring 21, and is a region located at a position farther from the power supply portion 40 than the first region 26. In addition, in the long side 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.

[0076] The line width W3 of the first direction wiring 21 in the first region 26 is thicker than the line width W1 of the first direction wiring 21 in the second region 27. That is, the line width of the first direction wiring 21 becomes thicker in the first region 26 located near the connection portion connected to the power supply portion 40, and becomes thinner in the second region 27 away from the power supply portion 40. Thus, the line width W3 of the first direction wiring 21 can be thickened in the connection portion (first region 26) connected to the power supply portion 40, which is a region where the current density is higher than other portions, thereby suppressing the disconnection of the first direction wiring 21.

[0077] The line width W3 of the first direction wiring 21 in the first region 26 is preferably set to be 150% or more of the line width W1 of the first direction wiring 21 in the second region 27 (1.5W1≦W3). Specifically, the line width W3 of the first direction wiring 21 in the first region 26 can be selected within a range of 0.15 μm or more. In addition, in the present embodiment, the line widths W3 of the plurality of first direction wirings 21 are all the same.

[0078] exist Figure 5 In FIG. 1 , the planar shape of the first region 26 is a rectangular shape elongated in the Y direction. The line width W3 of the first region 26 is substantially uniform in the first region 26 along the long side direction (Y direction) of the first direction wiring 21. In addition, the planar shape of the second region 27 is a rectangular shape elongated in the Y direction. The line width W1 of the second region 27 is substantially uniform in the second region 27 along the long side direction (Y direction) of the first direction wiring 21. In addition, the height H1 (length in the Z direction, refer to Figure 3 ) is uniform between the first region 26 and the second region 27. On the other hand, the line width W2 of the second direction wiring 22 is uniform between the second direction wiring 22 located near the power supply portion 40 and the second direction wiring 22 located away from the power supply portion 40.

[0079] The first region 26 is preferably located at least between the second-direction wiring 22 closest to the power supply section 40 (located closest to the negative side in the Y direction) and the power supply section 40. Figure 5 In the embodiment, the second direction wiring 22 is located between the second direction wiring 22 closest to the power supply unit 40 (the second one located on the positive side in the Y direction when viewed from the power supply unit 40) and the power supply unit 40. However, the present invention is not limited thereto, and the second direction wiring 22 may be located between the second direction wiring 22 closest to the power supply unit 40 (N is 3 or more) and the power supply unit 40.

[0080] Specifically, the length L4 of the first region 26 in the Y direction is preferably set to be greater than or equal to 0.1 mm and less than or equal to 0.5 mm. By setting the length L4 of the first region 26 in the Y direction to be greater than or equal to 0.1 mm, the line width W3 of the first direction wiring 21 can be thickened in the vicinity of the connection portion connected to the power supply portion 40 where the current density is higher than other portions, thereby suppressing the disconnection of the first direction wiring 21. In addition, by setting the length L4 of the first region 26 in the Y direction to be less than or equal to 0.5 mm, the region where the line width W3 of the first direction wiring 21 is thicker does not become too long. As a result, there is no need to worry about damaging the overall transparency of the wiring substrate 10.

[0081] The material of the first direction wiring 21 and the second direction wiring 22 can be any metal material as long as it has conductivity. In the present embodiment, the material of the first direction wiring 21 and the second direction wiring 22 is copper, but is not limited thereto. As the material of the first direction wiring 21 and the second direction wiring 22, metal materials such as gold, silver, copper, platinum, tin, aluminum, iron, nickel, etc. (including alloys of these materials) can be used.

[0082] In the present embodiment, the overall aperture ratio At of the wiring pattern area 20 can be set to a range of, for example, 87% or more and less than 100%. By setting the overall aperture ratio At of the wiring substrate 10 to this range, the conductivity and transparency of the wiring substrate 10 can be ensured. In addition, the aperture ratio refers to the ratio (%) of the area of ​​the opening region (the region where the metal parts such as the first direction wiring 21 and the second direction wiring 22 are not present and the substrate 11 is exposed) to the unit area of ​​a specified region (for example, a part of the wiring pattern area 20).

[0083] Refer again Figure 1 The power supply portion 40 is electrically connected to the wiring pattern area 20. The power supply portion 40 is composed of a conductive thin plate-like component in a roughly rectangular shape. The long side direction of the power supply portion 40 is parallel to the X direction, and the short side direction of the power supply portion 40 is parallel to the Y direction. In addition, the power supply portion 40 is arranged at the end of the long side direction of the substrate 11 (the negative end in the Y direction). Regarding the material of the power supply portion 40, metal materials such as gold, silver, copper, platinum, tin, aluminum, iron, nickel, etc. (including alloys of these materials) can be used. The power supply portion 40 is installed in the image display device 90 (refer to Figure 7 ) is electrically connected to the wireless communication circuit 92 of the image display device 90. In addition, the power supply unit 40 is provided on the front surface of the substrate 11, but is not limited thereto, and a part or all of the power supply unit 40 may also be located outside the periphery of the substrate 11.

[0084] And, if Figure 3 and Figure 4As shown, a protective layer 17 is formed on the front surface of the substrate 11 in a manner covering the wiring pattern area 20 and the power supply part 40. The protective layer 17 protects the wiring pattern area 20 and the power supply part 40, and is formed on substantially the entire area of ​​the front surface of the substrate 11. As the material of the protective layer 17, acrylic resins such as poly(methyl)acrylate, poly(ethyl)acrylate and their modified resins and copolymers, polyesters, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinyl butyral and their copolymers, polyurethanes, epoxy resins, polyamides, chlorinated polyolefins and other colorless and transparent insulating resins can be used. In addition, the thickness T2 of the protective layer 17 can be selected within the range of more than 0.3 μm and less than 100 μm. In addition, the protective layer 17 only needs to be formed to cover at least the wiring pattern area 20 in the substrate 11.

[0085] [Method for manufacturing wiring board]

[0086] Next, refer to Figure 6 (a) to (i) of the present embodiment describe a method for manufacturing a wiring board. Figure 6 (a) to (i) are cross-sectional views illustrating a method for manufacturing a wiring board according to the present embodiment.

[0087] First, if Figure 6 As shown in (a), a substrate 11 is prepared, and a conductive layer 51 is formed on substantially the entire area of ​​the front side of the substrate 11. In the present embodiment, the thickness of the conductive layer 51 is 200 nm. However, not limited thereto, the thickness of the conductive layer 51 can be appropriately selected within a range of 10 nm to 1000 nm. In the present embodiment, the conductive layer 51 is formed using copper by sputtering. As a method for forming the conductive layer 51, a plasma CVD method can also be used.

[0088] Then, if Figure 6 As shown in (b) of FIG. 1 , a photo-curable insulating resist 52 is applied to substantially the entire area of ​​the front surface of the substrate 11. Examples of the photo-curable insulating resist 52 include organic resins such as epoxy resins.

[0089] Next, a transparent stamping mold 53 ( Figure 6 (c)), the mold 53 and the substrate 11 are brought close to each other, and the photocurable insulating resist 52 is developed between the mold 53 and the substrate 11. Next, light is irradiated from the mold 53 side to cure the photocurable insulating resist 52, thereby forming an insulating layer 54. As a result, a groove 54a having a shape in which the convex portion 53a is transferred is formed on the front surface of the insulating layer 54. The groove 54a has a planar shape pattern corresponding to the first direction wiring 21 and the second direction wiring 22.

[0090] Then, the mold 53 is peeled off from the insulating layer 54, thereby obtaining Figure 6 The insulating layer 54 has a cross-sectional structure shown in (d). The direction in which the mold 53 is peeled off from the insulating layer 54 is preferably the Y direction in which the longer first-direction wiring 21 extends.

[0091] In this way, the groove 54a is formed on the front surface of the insulating layer 54 by the imprint method, so that the shape of the groove 54a can be fine. In addition, without being limited to this, the insulating layer 54 can also be formed by photolithography. In this case, the resist pattern is formed by photolithography so that the conductive layer 51 corresponding to the first direction wiring 21 and the second direction wiring 22 is exposed.

[0092] like Figure 6 As shown in (d), the residue of the insulating material may remain at the bottom of the groove 54a of the insulating layer 54. Therefore, the residue of the insulating material is removed by performing a wet treatment using a permanganate solution or N-methyl-2-pyrrolidone or a dry treatment using oxygen plasma. Figure 6 As shown in (e), a groove 54a that exposes the conductive layer 51 can be formed.

[0093] Then, if Figure 6 As shown in (f), the groove 54a of the insulating layer 54 is filled with the conductor 55. In this embodiment, the conductive layer 51 is used as a seed layer, and the groove 54a of the insulating layer 54 is filled with copper by using the electroplating method.

[0094] Next, if Figure 6 As shown in (g), the insulating layer 54 is removed. In this case, the insulating layer 54 on the substrate 11 is removed by performing a wet treatment using a permanganate solution or N-methyl-2-pyrrolidone, or a dry treatment using oxygen plasma.

[0095] Then, if Figure 6 As shown in (h), the conductive layer 51 on the front side of the substrate 11 is removed. At this time, the conductive layer 51 is etched in such a way that the front side of the substrate 11 is exposed by performing a wet treatment using hydrogen peroxide solution. In this way, a wiring substrate 10 having a substrate 11 and a wiring pattern area 20 arranged on the substrate 11 can be obtained. In this case, the wiring pattern area 20 includes a first direction wiring 21 and a second direction wiring 22. The above-mentioned conductor 55 includes a first direction wiring 21 and a second direction wiring 22. At this time, the power supply portion 40 can also be formed by a part of the conductor 55. Alternatively, a flat-plate-shaped power supply portion 40 can be prepared separately, and the power supply portion 40 can be electrically connected to the wiring pattern area 20.

[0096] Afterwards, if Figure 6As shown in (i), the protective layer 17 is formed in a manner covering the wiring pattern area 20 and the power supply portion 40 on the substrate 11. As a method for forming the protective layer 17, roll coating, gravure coating, reverse gravure coating, micro gravure coating, slot die coating, die coating, blade coating, inkjet coating, dispenser coating, kiss coating, spray coating, screen printing, offset printing, and flexographic printing can be used.

[0097] [Function of this embodiment]

[0098] Next, the operation of the wiring board having such a structure will be described.

[0099] like Figure 7 As shown, the wiring substrate 10 is incorporated into an image display device 90 having a display 91. The wiring substrate 10 is arranged on the display 91. As such an image display device 90, for example, a portable terminal device such as a smart phone and a tablet computer can be cited. The wiring pattern area 20 of the wiring substrate 10 is electrically connected to the wireless communication circuit 92 of the image display device 90 via the power supply unit 40. In this way, radio waves of a predetermined frequency can be transmitted and received via the wiring pattern area 20, so that communication can be performed using the image display device 90.

[0100] However, generally speaking, during the period when the wiring pattern area 20 is used to transmit and receive radio waves, there is a tendency for the current density to become higher near the power supply portion 40 in the wiring pattern area 20. Therefore, in the first direction wiring 21 near the power supply portion 40, especially when the wiring substrate 10 is used for a long time, it is easy to cause disconnection compared with other parts of the first direction wiring 21. In contrast, in the present embodiment, the line width W3 of the first direction wiring 21 in the first area 26 near the power supply portion 40 is made thicker than the line width W1 of the first direction wiring 21 in the second area 27 other than the first area 26. Thus, it is possible to improve the strength of the first direction wiring 21 near the power supply portion 40 (first area 26) where the current density is easy to become high and disconnection is easy to occur during long-term use, thereby suppressing the disconnection of the first direction wiring 21. In addition, even in the process of manufacturing the wiring substrate 10, the first direction wiring 21 near the power supply portion 40 is easy to cause disconnection compared with other parts. Therefore, the strength of the first direction wiring 21 in the vicinity of the power feeding portion 40 (the first region 26 ) can be improved, and disconnection of the first direction wiring 21 can be suppressed when manufacturing the wiring substrate 10 .

[0101] Furthermore, according to the present embodiment, since the wiring substrate 10 includes: the transparent substrate 11 and the wiring pattern region 20 disposed on the substrate 11 and including a plurality of first-direction wirings 21, the transparency of the wiring substrate 10 is ensured. Thus, when the wiring substrate 10 is disposed on the display 91, the display 91 can be seen from the opening 23 of the wiring pattern region 20, and the visual confirmation of the display 91 is not hindered.

[0102] Furthermore, according to the present embodiment, the wiring pattern region 20 includes a plurality of second direction wirings 22 connecting a plurality of first direction wirings 21. This makes it difficult for the first direction wirings 21 to be disconnected, and reduces the function of the first direction wirings 21.

[0103] Furthermore, according to the present embodiment, the first region 26 of the wiring pattern region 20 is located at least between the second direction wiring 22 closest to the power supply section 40 and the power supply section 40. Thus, the line width W3 of the first direction wiring 21 can be thickened near the connection portion connected to the power supply section 40, thereby increasing the strength of the first direction wiring 21 and suppressing the disconnection of the wiring. Furthermore, since the region where the line width W3 of the first direction wiring 21 is thicker does not become too long, there is no worry that the overall transparency of the wiring substrate 10 will be impaired.

[0104] In addition, according to the present embodiment, the length L4 of the first region 26 along the long side direction (Y direction) of the wiring pattern region 20 is greater than or equal to 0.1 mm and less than or equal to 0.5 mm. Thus, the line width of the first direction wiring 21 can be thickened near the connection portion connected to the power supply portion 40, thereby increasing the strength of the first direction wiring 21 and suppressing wire breakage. In addition, since the area where the line width W3 of the first direction wiring 21 is thicker does not become too long, there is no need to worry about damaging the overall transparency of the wiring substrate 10.

[0105] Furthermore, according to the present embodiment, the line width W3 of the first direction wiring 21 in the first region 26 is 150% or more of the line width W1 of the first direction wiring 21 in the second region 27. Thus, the line width of the first direction wiring 21 can be thickened near the connection portion connected to the power supply portion 40, thereby increasing the strength of the first direction wiring 21 and suppressing disconnection. Furthermore, since the region where the line width W3 of the first direction wiring 21 is thicker does not become too long, there is no worry about damaging the overall transparency of the wiring substrate 10.

[0106] In addition, according to the present embodiment, by thickening the line width W3 of the first direction wiring 21 in the first area 26, the first direction wiring 21 present in the first area 26 becomes low resistance. By adjusting the line width W3 of the first direction wiring 21 in the first area 26, the resistance value (impedance) can be controlled. As a result, impedance matching, which is particularly important in frequency domains such as millimeter waves and microwaves, can be easily performed. That is, in the connection portion of the first direction wiring 21, if the impedance of the first direction wiring 21 and the power supply unit 40 side is not approximately the same value, reflection will occur and electromagnetic waves may be difficult to transmit. In the present embodiment, in the connection portion where the first direction wiring 21 is connected to the power supply unit 40, by widening the line width W3 of the first direction wiring 21, the impedance difference between the first direction wiring 21 and the power supply unit 40 can be reduced.

[0107] Furthermore, according to the present embodiment, by increasing the line width W3 of the first direction wiring 21 in the first region 26, the bending resistance of the first direction wiring 21 can be improved. Figure 8 As shown, the following situation can be considered: the power supply unit 40 is arranged at the peripheral portion of the display 91, and the first direction wiring 21 existing in the first area 26 is bent. In this regard, according to this embodiment, by thickening the line width W3 of the first direction wiring 21 in the first area 26, it is possible to avoid the first direction wiring 21 from being broken when being bent.

[0108] In addition, if Figure 8 As shown, the wiring pattern area 20 is arranged on the display 91. In addition, the power supply portion 40 is arranged on the frame (frame) 93 around the display 91, or is arranged in a bent manner on the frame 93. In addition, the opening ratio of the wiring pattern area 20 is, for example, in the range of 87% or more and less than 100%, while the opening ratio of the power supply portion 40 is 0%. According to this embodiment, by thickening the line width W3 of the first direction wiring 21 in the first area 26, it is possible to suppress the rapid change in the opening ratio of the wiring pattern area 20 and the opening ratio of the power supply portion 40, and it is possible to make it difficult to see the wiring pattern area 20.

[0109] (Variation of the first embodiment)

[0110] Next, refer to Figures 9 to 14 , various modifications of the wiring substrate of this embodiment are described. Figures 9 to 14 1 is a diagram showing various modified examples of a wiring substrate. Figures 9 to 14 In the modified example shown, the structure of the wiring pattern area 20 is different, and the other structures are the same as those described above. Figures 1 to 7 The embodiments shown are substantially the same. Figures 9 to 14 In, with Figures 1 to 7 The same parts as shown are marked with the same reference numerals and detailed description is omitted.

[0111] (Variation 1 of the First Embodiment)

[0112] Fig. 9 A wiring board 10A according to a first modification of the present embodiment is shown. Fig. 9 In the embodiment, the first region 26 of the first direction wiring 21 is located only between the second direction wiring 22 closest to the power supply section 40 (closest to the negative side in the Y direction) and the power supply section 40. In this case, the decrease in the overall transparency of the wiring substrate 10 can be minimized while preventing the first direction wiring 21 from being disconnected.

[0113] (Variation 2 of the first embodiment)

[0114] Fig.10 A wiring board 10B according to a second modification of the present embodiment is shown. Fig.10 In the figure, the line width W3 of the first region 26 is not uniform along the long side direction (Y direction) of the first direction wiring 21. That is, the line width W3 of the first region 26 is widest near the power supply portion 40 and narrowest near the second region 27. In this case, the planar shape of the first direction wiring 21 in the first region 26 is a shape in which the line width W3 gradually narrows as it moves away from the power supply portion 40. Fig.10 In the embodiment, the planar shape of the first region 26 is a trapezoid or a triangle, and the two sides of the first region 26 are straight lines. However, the present invention is not limited thereto, and the two sides of the first region 26 may also be curved lines. Fig.10 The structure shown can improve the strength of the connection portion in the first region 26 connected to the power supply portion 40 with a higher current density, suppress the disconnection of the first direction wiring 21 in the connection portion connected to the power supply portion 40, and suppress the decrease in the overall transparency of the wiring substrate 10. In addition, in the connection portion between the first direction wiring 21 and the power supply portion 40, by gradually widening the line width W3 of the first direction wiring 21, it is possible to easily perform impedance matching between the first direction wiring 21 and the power supply portion 40 as described above.

[0115] (Variation 3 of the first embodiment)

[0116] Fig.11 A wiring board 10C according to a third modification of the present embodiment is shown. Fig.11, the line width W3 of the first region 26 is non-uniform along the long side direction (Y direction) of the first direction wiring 21. That is, the line width W3 of the first region 26 is widest near the power supply portion 40 and narrowest near the second region 27. In this case, the line width W3 of the first region 26 gradually becomes thinner from the vicinity of the power supply portion 40 to the vicinity of the second region 27. That is, the line width W3 between the power supply portion 40 and the second direction wiring 22 closest to the power supply portion 40 is the thickest. In addition, the line width W3 between the second direction wiring 22 closest to the power supply portion 40 and the second direction wiring 22 second closest to the power supply portion 40 is the second thickest. And, the line width W3 between the second direction wiring 22 second closest to the power supply portion 40 and the second direction wiring 22 third closest to the power supply portion 40 is the third thickest. In addition, without limitation to this, the line width W3 of the first region 26 may also be thinner in two stages or four or more stages from the vicinity of the power supply portion 40 to the vicinity of the second region 27. By setting Fig.11 The structure shown can improve the strength of the connection portion in the first area 26 connected to the power supply portion 40 with a higher current density, thereby suppressing the disconnection of the first direction wiring 21 in the connection portion connected to the power supply portion 40 and suppressing the decrease in the overall transparency of the wiring substrate 10.

[0117] (Variation 4 of the first embodiment)

[0118] Fig.12 A wiring board 10D according to a fourth modification of the present embodiment is shown. 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 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) is greater than 3B In addition, the line width of the first region 26 gradually increases from the first direction wiring 21 located near the center portion in the width direction toward the first direction wiring 21 located near the edge portion in the width direction.

[0119] Generally speaking, during the period of using the wiring pattern area 20 to transmit and receive radio waves, the current value flowing through the wiring pattern area 20 is not uniform in the width direction (X direction). Specifically, the current value flowing through the width direction edge of the wiring pattern area 20 is larger than the current value flowing through the width direction center of the wiring pattern area 20. Fig.12 The structure shown in the figure makes the line width W in the central part of the width direction of the wiring pattern area 20 3A The line width W at the edge of the wiring pattern region 20 is greater than 3B Thin (W 3A <W 3B). That is, the density of the first direction wiring 21 in the width direction edge portion where the current value is higher is made higher than the density of the first direction wiring 21 in the width direction center portion where the current value is lower. As a result, compared with the case where the mesh of the wiring pattern region 20 is uniform, the current distribution in the width direction center portion and the width direction edge portion of the wiring pattern region 20 becomes uniform, so that the characteristics (antenna characteristics, etc.) of the wiring pattern region 20 can be further improved.

[0120] (Variation 5 of the first embodiment)

[0121] Fig.13 A wiring board 10E according to a fifth modification of the present embodiment is shown. Fig.13 In the figure, the line width W3 of the first region 26 is not uniform along the long side direction (Y direction) of the first direction wiring 21. That is, the line width W3 of the first region 26 is widest near the power supply portion 40 and narrowest near the second region 27. In this case, the planar shape of the first direction wiring 21 in the first region 26 is a shape in which the line width W3 gradually narrows as it moves away from the power supply portion 40. Fig.13 In the embodiment, the planar shape of the first direction wiring 21 in the first region 26 is a trapezoid or a triangle. The trapezoid or the triangle is integrated with the trapezoid or the triangle constituting the first direction wiring 21 adjacent in the X direction. As a result, the connection between the first direction wiring 21 and the power supply portion 40 becomes smooth, and the impedance matching between the first direction wiring 21 and the power supply portion 40 can be easily performed as described above. In addition, the aperture ratio of the wiring pattern region 20 and the aperture ratio of the power supply portion 40 can be suppressed from changing sharply, and the wiring pattern region 20 can be made difficult to see.

[0122] (Variation 6 of the first embodiment)

[0123] Fig.14 FIG. 1 is an enlarged plan view showing a wiring board 10F according to a sixth modification of the present embodiment. Fig.14 In the embodiment, the first direction wiring 21 and the second direction wiring 22 intersect obliquely, and each opening 23 is formed into a rhombus when viewed from above. The first direction wiring 21 and the second direction wiring 22 are not parallel to any direction in the X direction and the Y direction, respectively. In a position adjacent to the power supply part 40, an area 28 surrounded by the power supply part 40, the first direction wiring 21 and the second direction wiring 22 is a non-opening part. When viewed from above, the area 28 is a triangle. That is, the area 28 is filled with metals constituting the first direction wiring 21, the second direction wiring 22 and the power supply part 40, and the substrate 11 is not exposed. As a result, the strength of the first direction wiring 21 and the second direction wiring 22 near the power supply part 40 (the first area 26) where the current density is likely to increase and disconnection is likely to occur during long-term use can be improved, thereby suppressing disconnection of the first direction wiring 21 and the second direction wiring 22.

[0124] In addition, all of the multiple regions 28 surrounded by the power supply portion 40, the first-direction wiring 21, and the second-direction wiring 22 may be non-opening portions, or only a part of the multiple regions 28 may be non-opening portions. In the latter case, for example, multiple regions 28 located near the center portion in the width direction (X direction) of the wiring pattern region 20 may be set as opening portions, and multiple regions 28 located near the edge portion in the width direction (X direction) of the wiring pattern region 20 may be set as non-opening portions. In this case, as described above, the density of the metal portion at the edge portion in the width direction of the wiring pattern region 20 with a higher current value can be made higher than the density of the metal portion at the center portion in the width direction of the wiring pattern region 20 with a lower current value. As a result, the current distribution is uniform in the center portion in the width direction and the edge portion in the width direction of the wiring pattern region 20, so the characteristics (antenna characteristics, etc.) of the wiring pattern region 20 can be further improved.

[0125] In addition, Figures 1 to 14 In the description, the case where the wiring pattern area 20 has the function of an antenna is used as an example, but it is not limited to this. The wiring pattern area 20 may also have functions such as hovering (a function that can be operated even if the user does not directly touch the display), fingerprint authentication, a heater, noise reduction (noise shielding), etc. In such a case, by making the line width W3 of the first direction wiring 21 in the first area 26 thicker than the line width W1 of the first direction wiring 21 in the second area 27, the disconnection of the first direction wiring 21 can be suppressed without damaging the transparency of the wiring substrate 10.

[0126] (Second embodiment)

[0127] Next, according to Figures 15 to 18 , the second embodiment is described. Figures 15 to 18 It is a figure which shows the 2nd embodiment. Figures 15 to 18 The second embodiment shown in the figure is mainly different in the structure of the power supply unit 40, and the other structures are the same as those of the Figures 1 to 14 The first embodiment shown is substantially the same. Figures 15 to 18 In, with Figures 1 to 14 The same parts as those in the embodiment shown are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, the following description will focus on the differences from the first embodiment.

[0128] [Structure of wiring board]

[0129] Reference Figures 15 to 17 , the structure of the wiring substrate of this embodiment is described. Figures 15 to 17 It is a figure which shows the wiring board of this embodiment.

[0130] like Fig.15As shown, the wiring substrate 10 of this embodiment is arranged on a display of an image display device, for example. Such a wiring substrate 10 includes: a transparent substrate 11; and wiring pattern areas 20 arranged on the substrate 11. In addition, each wiring pattern area 20 is electrically connected to a power supply unit 40.

[0131] In this embodiment, unlike the first embodiment, the first direction wiring 21 may have a uniform width as a whole. The area of ​​the opening 23 may also be uniform within the wiring pattern region 20. In this case, the size of the opening 23 does not vary within the wiring pattern region 20, making it difficult to see the wiring pattern region 20 with the naked eye. The shape of the opening 23 is preferably the same shape and the same size within the wiring pattern region 20, but it may be changed according to the location, etc., so as to be uneven on the entire surface.

[0132] The cross-sectional shape of the first direction wiring 21 is substantially uniform throughout the entire long side direction (Y direction) of the first direction wiring 21. In addition, the cross-sectional shape of the second direction wiring 22 is substantially uniform throughout the entire long side direction (X direction) of the second direction wiring 22. However, this is not limited to the above. In this embodiment, as in the case of the first embodiment, the line width of the first direction wiring 21 in the first region 26 located near the power supply portion 40 may be thicker than the line width of the first direction wiring 21 in the second region 27. In addition, the structure of the wiring pattern region 20 may be the same as in the case of the first embodiment.

[0133] Reference Fig.15 The power supply part 40 is electrically connected to each wiring pattern area 20, respectively. The power supply part 40 is composed of a conductive thin plate-like component in a roughly rectangular shape. The long side direction of the power supply part 40 is parallel to the X direction, and the short side direction of the power supply part 40 is parallel to the Y direction. In addition, the power supply part 40 is arranged at the end of the long side direction of the substrate 11 (the negative end in the Y direction). Regarding the material of the power supply part 40, metal materials such as gold, silver, copper, platinum, tin, aluminum, iron, nickel, etc. (including alloys of these materials) can be used. The power supply part 40 is installed in the image display device 90 (refer to Fig.18 ) is electrically connected to the wireless communication circuit 92 of the image display device 90 via the power supply line 95. In addition, the power supply unit 40 is provided on the front surface of the substrate 11, but is not limited thereto, and a part or all of the power supply unit 40 may also be located outside the periphery of the substrate 11. Fig.15 In the embodiment, each wiring pattern region 20 is connected to a corresponding power supply portion 40 , but the present invention is not limited thereto. One power supply portion 40 may be electrically connected to a plurality of wiring pattern regions 20 .

[0134] like Fig.16As shown, a plurality of first-direction wirings 21 are electrically connected to the power supply portion 40 on the negative side in the Y direction, respectively. In this case, the power supply portion 40 is formed integrally with the wiring pattern area 20. A connection area 46 electrically connected to the power supply line 95 described later is formed on the side of the power supply portion 40 opposite to the wiring pattern area 20 (negative side in the Y direction). The length L6 of the power supply portion 40 in the long side direction (X direction) can be set to be greater than 1 mm and less than 10 mm, and the length L5 of the power supply portion 40 in the short side direction (Y direction) can be set to be greater than 0.5 mm and less than 3 mm. In addition, the thickness T3 of the power supply portion 40 (refer to Fig.17 ) can be set to be equal to the height H1 of the first direction wiring 21 (refer to Figure 3 ) and the height H2 of the second direction wiring 22 (refer to Figure 4 ) is the same, for example, it can be selected in the range of 0.1μm to 5.0μm.

[0135] In the present embodiment, the power supply part 40 has a plurality of through holes 45. The through holes 45 are arranged in the power supply part 40 in a lattice shape when viewed from above. That is, the through holes 45 are arranged in multiple stages and multiple columns in the surface of the power supply part 40, and multiple holes are arranged in the X direction and the Y direction respectively. The through holes 45 penetrate the power supply part 40 in the thickness direction (Z direction), and the transparent substrate 11 is exposed from each through hole 45. In this case, the through holes 45 are arranged in substantially the entire area within the surface of the power supply part 40, but are not limited to this. The through holes 45 are preferably arranged at least in the area covered by the protective layer 17 and in the connection area 46. Thereby, the close contact between the protective layer 17 and the power supply part 40, and the close contact between the solder connecting the power supply line 95 and the power supply part 40 can be improved.

[0136] When viewed from above, each through hole 45 has a square shape. The width (length of one side) W4 of each through hole 45 can also be set to be greater than 50μm and less than 500μm. In addition, without limitation thereto, the planar shape of the through hole 45 can also be set to a polygonal shape such as a circular shape, an elliptical shape, a rectangular shape, etc. In addition, the plurality of through holes 45 are arranged at uniform intervals from each other in the X direction and the Y direction. Specifically, the spacing P3 of the plurality of through holes 45 in the X direction can be set to, for example, greater than 100μm and less than 500μm, and the spacing P4 of the plurality of through holes 45 in the Y direction can be set to, for example, greater than 100μm and less than 500μm. In addition, without limitation thereto, the plurality of through holes 45 can also be arranged at uniform intervals only in any one direction of the X direction and the Y direction. In the present embodiment, the pitch P3 of the through holes 45 in the X direction is equal to the pitch P4 of the through holes 45 in the Y direction (P3=P4), but the present invention is not limited thereto, and the pitch P3 and the pitch P4 may be different from each other.

[0137] And, if Fig.17As shown, a protective layer 17 is formed on the front surface of the substrate 11 in a manner covering the wiring pattern area 20 and the power supply portion 40. The protective layer 17 protects the wiring pattern area 20 and the power supply portion 40 and may be formed on substantially the entire area of ​​the front surface of the substrate 11. Other than this, the structure of the protective layer 17 may be the same as that of the first embodiment.

[0138] like Fig.17 As shown, the protective layer 17 has a plurality of protrusions 17a protruding toward the substrate 11 side. The protrusions 17a have a shape that is a transfer of the through hole 45 of the power supply portion 40. The end of the protrusion 17a (the negative end in the Z direction) is in contact with the front surface of the substrate 11. The protrusions 17a of the protective layer 17 enter into each through hole 45 of the power supply portion 40 and solidify, whereby the protrusions 17a act as anchors. As a result, the protective layer 17 is firmly in contact with the power supply portion 40, so that the protective layer 17 is not peeled off from the power supply portion 40. In addition, since it is easy to connect the power supply line 95 to the power supply portion 40, the protective layer 17 may not cover the connection area 46 of the power supply portion 40.

[0139] [Method for manufacturing wiring board]

[0140] The wiring substrate of this embodiment can be compared with the case of the first embodiment ( Figure 6 In addition, in this embodiment, the power supply unit 40 having a plurality of through holes 45 can also be manufactured when the conductive layer 51 on the front surface of the substrate 11 is removed (see Figure 6 (h)) is formed by a part of the conductor 55. Alternatively, a flat-plate-shaped power supply portion 40 having a plurality of through holes 45 may be separately prepared and the power supply portion 40 may be electrically connected to the wiring pattern region 20. Then, when the protective layer 17 is formed in a manner covering the wiring pattern region 20 and the power supply portion 40 on the substrate 11 (see Figure 6 (i)), a portion of the protective layer 17 enters the plurality of through holes 45 and solidifies, thereby forming a protrusion 17a and firmly bonding with the power supply portion 40 (see Fig.17 ).

[0141] [Function of this embodiment]

[0142] Next, the operation of the wiring board having such a structure will be described.

[0143] like Fig.18As shown, the wiring substrate 10 is incorporated into an image display device 90 having a display 91. The wiring substrate 10 is arranged on the display 91. As such an image display device 90, for example, a portable terminal device such as a smart phone and a tablet computer can be cited. The wiring pattern area 20 of the wiring substrate 10 is electrically connected to the wireless communication circuit 92 of the image display device 90 via the power supply unit 40 and the power supply line 95. In this way, radio waves of a predetermined frequency can be transmitted and received via the wiring pattern area 20, and communication can be performed using the image display device 90.

[0144] However, generally speaking, the power supply portion 40 contacts the protective layer 17 with a larger area than the first direction wiring 21 and the second direction wiring 22. On the other hand, the metal power supply portion 40 and the resin protective layer 17 are made of different materials, so their adhesion is not necessarily strong. Therefore, it is also conceivable that the protective layer 17 is peeled off from the power supply portion 40 when a force is applied to the wiring substrate 10 in a bending direction during use of the image display device 90, and the protective layer 17 is peeled off from the entire surface of the substrate 11 from this point.

[0145] In contrast, according to the present embodiment, since the power supply portion 40 has a plurality of through holes 45 in the surface, a portion of the protective layer 17 (protrusion 17a) entering the through holes 45 serves as an anchor and is firmly bonded to the power supply portion 40. Thus, the protective layer 17 can be prevented from peeling off from the power supply portion 40.

[0146] Furthermore, according to the present embodiment, the solder for connecting the power supply line 95 to the power supply part 40 can be inserted into the plurality of through holes 45 of the power supply part 40. Thus, a portion of the solder entering the through hole 45 becomes an anchor and is coupled to the power supply part 40. Thus, the power supply line 95 and the power supply part 40 can be firmly connected. Furthermore, by providing the plurality of through holes 45 in the power supply part 40, the flow of the solder can be prevented in a manner that prevents the solder from excessively wetting and spreading.

[0147] Furthermore, according to the present embodiment, since the wiring substrate 10 includes: the transparent substrate 11 and the wiring pattern region 20 disposed on the substrate 11 and including a plurality of first-direction wirings 21, the transparency of the wiring substrate 10 is ensured. Thus, when the wiring substrate 10 is disposed on the display 91, the display 91 can be seen from the opening 23 of the wiring pattern region 20, and the visual confirmation of the display 91 is not hindered.

[0148] Furthermore, according to the present embodiment, the wiring pattern region 20 includes a plurality of second direction wirings 22 connecting a plurality of first direction wirings 21. This makes it difficult for the first direction wirings 21 to be disconnected, and reduces the function of the first direction wirings 21.

[0149] Furthermore, according to the present embodiment, the protective layer 17 is formed so as to cover the wiring pattern region 20 and the power supply portion 40. Thus, the wiring pattern region 20 and the power supply portion 40 can be protected from external impact and the like.

[0150] According to the present embodiment, the plurality of through holes 45 are arranged in multiple stages and multiple rows within the surface of the power supply portion 40 . This allows the protective layer 17 and the through holes 45 to be connected over a wide area of ​​the power supply portion 40 .

[0151] Furthermore, according to the present embodiment, the plurality of through holes 45 are arranged at uniform intervals in at least one direction. This allows the protective layer 17 and the through holes 45 to be connected with substantially uniform strength within the plane.

[0152] In addition, the power supply unit 40 is sometimes joined to the circuit substrate of the image display device 90 using a joint portion not shown in the figure. In this case, since the power supply unit 40 has a plurality of through holes 45, the surface area of ​​the power supply unit 40 can be increased, and the close contact between the power supply unit 40 and the joint portion can be improved. In addition, as such a joint portion, for example, an anisotropic conductive film (ACF: Anisotropic Conductive Film) can be cited. In addition, the circuit substrate can also be a substrate formed of a flexible material such as FPC (Flexible Printed Circuits: Flexible Printed Circuits).

[0153] However, in recent years, the development of portable terminal devices for the fifth generation of communication, i.e., 5G (Generation), has been carried out. When the wiring pattern area 20 of the wiring substrate 10 is used as, for example, an antenna for 5G (particularly an antenna for millimeter waves), the radio waves (millimeter waves) transmitted and received by the wiring pattern area 20 are higher frequencies than those transmitted and received by the antenna for 4G, for example.

[0154] Generally speaking, when an alternating current flows through a wiring, the higher the frequency, the more difficult it is for the current to flow through the center of the wiring, so the current flows on the surface of the wiring. In this way, the phenomenon that the current flows only on the surface when an alternating current flows through the wiring is called the skin effect. In addition, the skin depth refers to the depth from the wiring surface that is attenuated to 1 / e (about 0.37) times the current on the wiring surface where the current is most likely to flow. The skin depth δ can usually be calculated using the following formula.

[0155] [Formula 1]

[0156]

[0157] In the above formula, ω is the angular frequency (=2πf), and μ is the guiding magnetic constant (4π×10 -7[H / m]), σ refers to the electrical conductivity of the conductor constituting the wiring (5.8×10 7 [S / m]). Regarding the skin depth δ of the copper wiring, when the frequency is 0.8 GHz, δ = about 2.3 μm, when the frequency is 2.4 GHz, δ = about 1.3 μm, when the frequency is 4.4 GHz, δ = about 1.0 μm, and when the frequency is 6 GHz, δ = about 0.85 μm. In addition, the radio waves (millimeter waves) transmitted and received by the antenna for 5G are high-frequency (28 GHz to 39 GHz) compared with the radio waves transmitted and received by the antenna for 4G. For example, when the frequency of the current is 28 GHz to 39 GHz, δ = about 0.3 μm to about 0.4 μm.

[0158] In this way, the current flows from the surface of the wiring at a depth equivalent to the skin depth δ. Therefore, especially when the radio waves received and transmitted by the wiring pattern area 20 are high-frequency (for example, 28 GHz to 39 GHz), since the skin depth δ is small, it is necessary to smooth the surfaces of the first direction wiring 21 and the second direction wiring 22. In the present embodiment, since the wiring pattern area 20 and the power supply part 40 are made at the same time, the surface of the power supply part 40 is also smoothed together with the surface of the wiring pattern area 20. On the other hand, since the solder and the joint (ACF) are connected to the power supply part 40, it is necessary to improve the adhesion between the power supply part 40 and the solder and the joint (ACF). Therefore, in the present embodiment, a plurality of through holes 45 are formed in the power supply part 40 to increase the surface area of ​​the power supply part 40, thereby improving the adhesion between the power supply part 40 and the solder and the joint (ACF).

[0159] (Variation of the Second Embodiment)

[0160] Next, refer to Figures 19 to 22 , various modifications of the wiring substrate of this embodiment are described. Figures 19 to 22 1 is a diagram showing various modified examples of a wiring substrate. Figures 19 to 22 In the modified example shown, the structure of the power supply portion 40 or the wiring pattern area 20 is different, and the other structures are the same as those described above. Figures 15 to 18 The embodiments shown are substantially the same. Figures 19 to 22 In, with Figures 15 to 18 The same parts as shown are marked with the same reference numerals and detailed description is omitted.

[0161] (Variation 1 of the Second Embodiment)

[0162] Fig.19(a) to (c) show a wiring board 10G of a modification example 1 of the present embodiment. In the above embodiment, the case where the plurality of through holes 45 are square in plan view and are arranged in a grid pattern within the surface of the power supply portion 40 is described as an example, but the present invention is not limited to this. Fig.19 As shown in (a), it is also possible that, when viewed from above, the plurality of through holes 45 are each square and are arranged in a staggered manner (staggered) within the surface of the power supply portion 40. Fig.19 As shown in (b), the plurality of through holes 45 may each have a circular shape when viewed from above, and may be arranged in a grid pattern within the surface of the power supply portion 40. Fig.19 As shown in (c), the plurality of through holes 45 may each have a rhombus shape when viewed from above, and may be arranged in a lattice pattern within the surface of the power supply portion 40. In addition, each through hole 45 may also be formed into a polygon such as a parallelogram, trapezoid, triangle, hexagon, or an ellipse when viewed from above.

[0163] (Variation 2 of the Second Embodiment)

[0164] Fig. 20 (a)-(b) show a wiring board 10H according to a second modification of the present embodiment. Fig. 20 As shown in (a)-(b) of FIG. 1 , the area and pitch of the plurality of through holes 45 may be different in the region close to the wiring pattern region 20 and the region far from the wiring pattern region 20. For example, Fig. 20 As shown in (a), the area of ​​the plurality of through holes 45 (the width W4 of the through holes 45) may also be formed to be larger in the region closer to the wiring pattern region 20 and gradually smaller as it is farther away from the wiring pattern region 20. Fig. 20 As shown in (b), the plurality of through holes 45 may also be formed such that the closer the area is to the wiring pattern area 20, the smaller the spacing P4 is, and the farther away from the wiring pattern area 20, the more gradually the spacing P4 increases. Thus, with respect to the resistance value of the power supply portion 40, the area away from the wiring pattern area 20 is lower than the area close to the wiring pattern area 20. In this way, by adjusting the area and spacing of the plurality of through holes 45, the resistance value (impedance) can be controlled. Thus, impedance matching, which is important particularly in frequency domains such as millimeter waves and microwaves, can be easily performed. In the present embodiment, in the power supply portion 40 located at the connection portion between the wiring pattern area 20 and the power supply line 95, the impedance difference between the wiring pattern area 20 and the power supply line 95 can be reduced.

[0165] (Variation 3 of the Second Embodiment)

[0166] Fig.21 FIG. 1 shows a wiring board 10I according to a third variation of the present embodiment. Fig.21As shown, similarly to the first embodiment, the line width W3 of the first direction wiring 21 in the first region 26 may be made thicker than the line width W1 of the first direction wiring 21 in the second region 27. In this case, by adjusting the line width W3 of the first direction wiring 21 in the first region 26, the resistance value (impedance) of the first direction wiring 21 can be controlled, and by adjusting the number and shape of the plurality of through holes 45, the resistance value (impedance) of the power supply portion 40 can be controlled. Thus, impedance matching between the first direction wiring 21 and the power supply portion 40 can be easily performed.

[0167] (Variation 4 of the Second Embodiment)

[0168] Fig. 22 FIG. 1 shows a wiring board 10J according to a fourth variation of the present embodiment. Fig. 22 As shown, in the power supply portion 40, a plurality of non-through recesses 47 may be provided instead of the through holes 45. When viewed from above, the non-through recesses 47 are arranged in a lattice pattern in the power supply portion 40. That is, the non-through recesses 47 are arranged in multiple stages and multiple columns in the surface of the power supply portion 40, and multiple recesses are arranged in the X direction and the Y direction, respectively. The non-through recesses 47 do not penetrate the power supply portion 40 in the thickness direction (Z direction). In addition, the depth D1 of the non-through recesses 47 can be selected, for example, within a range of not less than 0.1 μm and not more than 3.0 μm. In the case of making the non-through recesses 47, in the step of removing the conductive layer 51 on the front surface of the substrate 11 (refer to Figure 6 In (h)), the power supply portion 40 is covered with a resist or the like so that the conductive layer 51 in the power supply portion 40 remains, thereby forming a non-through recess 47 in the power supply portion 40. In addition, the planar shape or configuration of the non-through recess 47 can be set to be substantially the same as that of the through hole 45 described above.

[0169] In addition, Figures 15 to 22 In the description, the wiring pattern area 20 is described as an example in which the wiring pattern area 20 has the function of an antenna, but the present invention is not limited thereto. The wiring pattern area 20 may also have functions such as hovering (a function that enables operation even if the user does not directly touch the display), fingerprint authentication, a heater, noise reduction (noise shielding), and the like.

[0170] The plurality of components disclosed in the above-mentioned embodiments and modifications may be combined as needed, or some components may be deleted from all the components shown in the above-mentioned embodiments and modifications.

Claims

1. A wiring substrate, wherein: The wiring substrate comprises: substrate; A wiring pattern area, which is arranged on the substrate and includes a plurality of wirings; a power supply portion electrically connected to the plurality of wirings in the wiring pattern area; and a protective layer formed on the substrate, The power supply portion has a plurality of through holes or a plurality of non-through recesses, The power supply portion includes a region covered by the protective layer and a connection region not covered by the protective layer.

2. The wiring substrate according to claim 1, wherein The plurality of through holes or the plurality of non-through recesses are arranged in the connection region.

3. The wiring substrate according to claim 1, wherein The plurality of through holes or the plurality of non-through recesses are arranged in a plurality of stages and in a plurality of rows within a surface of the power supply portion.

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

5. The wiring substrate according to claim 1, wherein The width of each through hole or each non-through recessed portion is 50 μm or more and 500 μm or less.

6. The wiring substrate according to claim 1, wherein The pitch of the plurality of through holes or the plurality of non-through recesses is greater than or equal to 100 μm and less than or equal to 500 μm.

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

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

9. The wiring substrate according to claim 1, wherein The areas or pitches of the plurality of through holes or the plurality of non-through recesses are different between a region close to the wiring pattern region and a region far from the wiring pattern region.

10. A method for manufacturing a wiring substrate, wherein: The method for manufacturing the wiring substrate comprises the following steps: Prepare substrate; forming a wiring pattern region and a power supply portion on the substrate, wherein the wiring pattern region includes a plurality of wirings, and the power supply portion is electrically connected to the plurality of wirings in the wiring pattern region; and forming a protective layer on the substrate, The power supply portion has a plurality of through holes or a plurality of non-through recesses, The power supply portion includes a region covered by the protective layer and a connection region not covered by the protective layer.

Images