Wiring substrate, image display device, and method for producing wiring substrate

Abstract

This wiring substrate comprises a transparent substrate and a mesh wiring layer that is disposed on the substrate. The mesh wiring layer includes wiring. An opening is formed by being surrounded by the wiring. Isolated wiring that is electrically independent from the wiring is provided in the opening.

Description

Wiring board, image display device, and method of manufacturing wiring board

[0001] An embodiment of the present disclosure relates to a wiring substrate, an image display device, and a method for manufacturing the wiring substrate.

[0002] Currently, mobile terminal devices such as smartphones, tablets, and smart glasses (AR, MR, etc.) are becoming more functional, smaller, thinner, and lighter. These mobile terminal devices use multiple communication bands. Therefore, multiple antennas corresponding to the communication bands are required. 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, a 5G (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 freedom of antenna design. Furthermore, because antennas are built into a limited space, radio wave sensitivity is not always satisfactory.

[0003] For this reason, a film antenna that can be mounted in the display area of ​​a mobile terminal device or the transparent area of ​​smart glasses has been developed. This film antenna is a transparent antenna in which an antenna pattern is formed on a transparent substrate. The antenna pattern is formed by a mesh-like conductive mesh layer. The conductive mesh layer includes a conductive portion as a formed portion of an opaque conductive layer and a large number of openings as a non-formed portion.

[0004] JP 2011-66610 A Japanese Patent No. 5636735 Japanese Patent No. 5695947

[0005] In a conventional film antenna, for example, one or more conductive mesh layers are formed on a transparent substrate, and in this case, it is required to make the conductive mesh layers less visible.

[0006] An object of the present embodiment is to provide a wiring board, an image display device, and a method for manufacturing a wiring board, which are capable of making a mesh wiring layer less visible.

[0007] Embodiments of the present disclosure relate to the following [1] to

[16] .

[0008] [1] A wiring board comprising: a transparent substrate; and a mesh wiring layer disposed on the substrate, wherein the mesh wiring layer includes wiring, and an opening is formed by being surrounded by the wiring, and an isolated wiring electrically independent from the wiring is provided within the opening.

[0009] [2] The wiring board according to [1], wherein the area ratio of the isolated wiring in the opening is 0.1% or more and 0.3% or less.

[0010] [3] The wiring board according to [1] or [2], wherein the distance between the wiring and the isolated wiring is 4.0 μm or more and 400 μm or less.

[0011] [4] The wiring board according to any one of [1] to [3], wherein the pitch of the isolated wiring is 500 μm or less.

[0012] [5] The wiring board according to any one of [1] to [4], wherein the line width of the isolated wiring is 3.0 μm or less.

[0013] [6] The wiring board according to any one of [1] to [5], wherein the length of the isolated wiring is 50 μm or less.

[0014] [7] The wiring board according to any one of [1] to [6], wherein the isolated wirings are separated from each other via cutouts, and the length of the cutouts is 4.0 μm or more and 400 μm or less.

[0015] [8] The wiring board according to any one of [1] to [7], wherein the pitch of the wiring is 500 μm or more and 10 mm or less.

[0016] [9] The wiring board according to any one of [1] to [8], wherein the wiring has a line width of 3.0 μm or less.

[0017]

[10] The wiring board according to any one of [1] to [9], wherein the mesh wiring layer has an aperture ratio of 98% or more and less than 100%.

[0018]

[11] The wiring board according to any one of [1] to

[10] , wherein at least one of the wiring and the isolated wiring is arranged irregularly.

[0019]

[12] The wiring board according to any one of [1] to

[11] , wherein a dummy wiring layer electrically independent from the mesh wiring layer is provided around the mesh wiring layer.

[0020]

[13] The wiring board according to

[12] , wherein a plurality of the dummy wiring layers are provided, and the aperture ratios of the mesh wiring layer and the dummy wiring layer increase stepwise from the mesh wiring layer toward the dummy wiring layer farther from the mesh wiring layer.

[0021]

[14] The wiring board according to any one of [1] to

[13] , having a radio wave transmitting and receiving function.

[0022]

[15] An image display device comprising: the wiring board according to

[14] ; and a display device laminated on the wiring board.

[0023]

[16] A method for manufacturing a wiring board, comprising: a step of preparing a substrate having transparency; and a step of forming a mesh wiring layer on the substrate, wherein the mesh wiring layer includes wiring, an opening is formed by being surrounded by the wiring, and an isolated wiring that is electrically independent from the wiring is provided within the opening.

[0024] According to the embodiment of the present disclosure, the mesh wiring layer can be made less visible.

[0025] FIG. 1 is a plan view showing an image display device according to an embodiment. FIG. 2 is a cross-sectional view (cross-sectional view taken along line II-II in FIG. 1) showing an image display device according to an embodiment. FIG. 3 is a plan view showing a wiring board according to an embodiment. FIG. 4 is an enlarged plan view showing a wiring board according to an embodiment. FIG. 5 is a cross-sectional view (cross-sectional view taken along line V-V in FIG. 4) showing a wiring board according to an embodiment. FIG. 6 is a cross-sectional view (cross-sectional view taken along line VI-VI in FIG. 4) showing a wiring board according to an embodiment. FIG. 7 is a cross-sectional view showing a module according to an embodiment. FIG. 8A is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 8B is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 8C is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 8D is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 8E is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 8F is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. FIG. 9A is a cross-sectional view showing a method for manufacturing a module according to an embodiment. FIG. 9B is a cross-sectional view showing a method for manufacturing a module according to an embodiment. FIG. 9C is a cross-sectional view showing a method for manufacturing a module according to an embodiment. FIG. 10A is a cross-sectional view showing a method for manufacturing an image display device according to an embodiment. FIG. 10B is a cross-sectional view showing a method for manufacturing an image display device according to an embodiment. FIG. 10C is a cross-sectional view showing a method for manufacturing an image display device according to an embodiment. FIG. 10D is a cross-sectional view showing a method for manufacturing an image display device according to an embodiment. FIG. 11 is an enlarged plan view showing a wiring board of an image display device according to a first modified example. FIG. 12 is an enlarged plan view showing a wiring board of an image display device according to a second modified example. FIG. 13 is a plan view showing a wiring board of an image display device according to a third modified example. FIG. 14 is an enlarged plan view showing a wiring board of an image display device according to the third modified example. FIG. 15 is a plan view showing a wiring board of an image display device according to a fourth modified example. FIG. 16 is an enlarged plan view showing a wiring board of an image display device according to the fourth modified example. FIG. 17 is an enlarged plan view showing a wiring board of an image display device according to a fifth modified example.

[0026] First, one embodiment will be described with reference to Figures 1 to 10D. Figures 1 to 10D are diagrams showing this embodiment.

[0027] The figures shown below are schematic diagrams. 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, the same 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 interpreted not only to mean their strict meanings but also to include substantially the same state.

[0028] In the following embodiments, the "X direction" refers to a direction parallel to one side of the image display device. The "Y direction" refers to a direction perpendicular to the X direction and parallel to another side of the image display device. The "Z direction" refers to a direction perpendicular to both the X direction and the Y direction and parallel to the thickness direction of the image display device. The "front surface" refers to the surface on the positive side of the Z direction, which is the light-emitting surface side of the image display device and faces the viewer. The "rear surface" refers to the surface on the negative side of the Z direction, which is the surface opposite to the light-emitting surface of the image display device and the surface facing the viewer. In the present embodiment, the mesh wiring layer 20 is described as having a radio wave transmitting and receiving function (functioning as an antenna), but the mesh wiring layer 20 does not necessarily have to have a radio wave transmitting and receiving function (functioning as an antenna).

[0029] The configuration of the image display device according to this embodiment will be described with reference to FIGS.

[0030] As shown in FIGS. 1 and 2 , an image display device 60 according to the present embodiment includes a laminate 70 for an image display device and a display device 61 laminated on the laminate 70 for an image display device. As shown in FIG. 2 , the laminate 70 for an image display device includes a wiring substrate 10, a first transparent adhesive layer 95, and a second transparent adhesive layer 96. The laminate 70 for an image display device also includes a cover glass 75 and a decorative layer 74. The cover glass 75 and the decorative layer 74 are disposed on the wiring substrate 10 via the first transparent adhesive layer 95. Note that an impact absorbing layer (not shown) or the like may be disposed between the first transparent adhesive layer 95 and the cover glass 75. A module 80A is also configured by the wiring substrate 10 and a power supply line 85 electrically connected to the wiring substrate 10.

[0031] The wiring board 10 of the module 80A has a substrate 11, a mesh wiring layer 20, and a power supply unit 40. As shown in Fig. 2, the substrate 11 includes a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The mesh wiring layer 20 is disposed on the first surface 11a of the substrate 11. The power supply unit 40 is electrically connected to the mesh wiring layer 20.

[0032] 2 , the image display device 60 has a light-emitting surface 64. The above-described wiring substrate 10 is located on the light-emitting surface 64 side (positive side in the Z direction) of the display device 61. A communication module 63 is disposed on the opposite side of the light-emitting surface 64 (negative side in the Z direction) of the display device 61. The image display device laminate 70, the display device 61, and the communication module 63 are housed in a housing 62.

[0033] 1 and 2 , radio waves of a predetermined frequency (e.g., a frequency higher than 1 GHz) can be transmitted and received via a communication module 63, enabling communication. The communication module 63 may include any of a millimeter wave antenna, a telephone antenna, a Wi-Fi antenna, a 3G antenna, a 4G antenna, a 5G antenna, an LTE antenna, a Bluetooth (registered trademark) antenna, an NFC antenna, etc. Examples of such an image display device 60 include mobile terminal devices such as smartphones and tablets.

[0034] The display device 61 is, for example, an organic EL (Electro Luminescence) display device. The display device 61 may be configured to be easily deformable. For example, the rigidity of the display device 61 may be lower than the rigidity of the cover glass 75. The display device 61 may include, for example, a metal layer, a support substrate, a resin substrate, a thin film transistor (TFT), and an organic EL layer (not shown). A touch sensor (not shown) may be disposed on the display device 61. Note that the display device 61 is not limited to an organic EL display device. For example, the display device 61 may be another display device that has the ability to emit light itself, or may be a micro LED display device including micro LED elements (light emitters). The display device 61 may also be a liquid crystal display device including liquid crystal.

[0035] Next, the laminate 70 for an image display device will be described in detail. As described above, the laminate 70 for an image display device includes the wiring substrate 10, the first transparent adhesive layer 95, and the second transparent adhesive layer 96. As described above, the laminate 70 for an image display device also includes the cover glass 75 and the decorative layer 74. The laminate 70 for an image display device may be incorporated into a head-mounted display (smart glasses) by being attached to a frame (not shown).

[0036] The cover glass 75 of the laminate 70 for an image display device is located on the first surface 11a side of the substrate 11 of the wiring board 10. The first transparent adhesive layer 95 is located between the substrate 11 of the wiring board 10 and the cover glass 75. The decorative layer 74 is located between the cover glass 75 and the first transparent adhesive layer 95. The second transparent adhesive layer 96 is located on the second surface 11b side of the substrate 11 of the wiring board 10. Here, the first transparent adhesive layer 95 of the laminate 70 for an image display device will be described first. Details of the wiring board 10 will be described later.

[0037] The first transparent adhesive layer 95 is an adhesive layer that directly or indirectly bonds the wiring substrate 10 to the decorative layer 74 and the cover glass 75. This first transparent adhesive layer 95 is located on the first surface 11a side of the substrate 11. The first transparent adhesive layer 95 is optically transparent and may be an OCA (Optical Clear Adhesive) layer. The OCA layer is a layer prepared, for example, as follows: First, a liquid curable adhesive layer composition containing a polymerizable compound is applied to a release film such as polyethylene terephthalate (PET). Next, the composition is cured using, for example, ultraviolet (UV) light to obtain an OCA sheet. After the OCA sheet is attached to an object, the release film is peeled off and removed to obtain the OCA layer. The material of the first transparent adhesive layer 95 may be an acrylic resin, a silicone resin, a urethane resin, or the like. In particular, the first transparent adhesive layer 95 may contain an acrylic resin. In this case, it is preferable that the second transparent adhesive layer 96 contains an acrylic resin. This substantially eliminates the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, and more reliably suppresses the reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0038] The first transparent adhesive layer 95 may have a visible light transmittance of 85% or more, preferably 90% or more. There is no particular upper limit to the visible light transmittance of the first transparent adhesive layer 95, but it may be, for example, 100% or less. By setting the visible light transmittance of the first transparent adhesive layer 95 within the above range, the transparency of the laminate 70 for an image display device can be increased, making the display device 61 of the image display device 60 easier to see. Visible light refers to light with a wavelength of 400 nm or more and 700 nm or less. A visible light transmittance of 85% or more means that, when the absorbance of the member to be measured (e.g., the first transparent adhesive layer 95) is measured, the transmittance is 85% or more across the entire wavelength range of 400 nm or more and 700 nm or less. Absorbance measurements can be performed using a spectrophotometer (V-670 spectrometer manufactured by JASCO Corporation).

[0039] As described above, the wiring substrate 10 is disposed on the light-emitting surface 64 side of the display device 61. In this case, the wiring substrate 10 is located between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. More specifically, a portion of the substrate 11 of the wiring substrate 10 is disposed in a portion of the area between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. In this case, the first transparent adhesive layer 95, the second transparent adhesive layer 96, the display device 61, and the cover glass 75 each have a larger area than the substrate 11 of the wiring substrate 10. By disposing the substrate 11 of the wiring substrate 10 in a portion of the image display device 60 rather than over the entire surface in a plan view, the area of ​​the wiring substrate 10 can be reduced. Therefore, when fabricating the first directional wiring 21 and the second directional wiring 22 of the wiring substrate 10 (described later), multiple first directional wirings 21 and second directional wirings 22 can be fabricated at the same time. This reduces the manufacturing cost per wiring substrate 10. The substrate 11 of the wiring substrate 10 may be disposed over the entire surface of the image display device 60 in plan view. In this case, the time required for positioning the wiring substrate 10 on the display device 61 can be reduced.

[0040] As described above, the wiring substrate 10 includes a transparent substrate 11 and a mesh wiring layer 20 disposed on the first surface 11a of the substrate 11. The power supply unit 40 is electrically connected to the mesh wiring layer 20. The power supply unit 40 is electrically connected to the communication module 63 via a power supply line 85. A portion of the wiring substrate 10 is not disposed between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, but protrudes outward (toward the negative Y direction) from between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. Specifically, the region of the wiring substrate 10 where the power supply unit 40 is disposed protrudes outward. This facilitates electrical connection between the power supply unit 40 and the communication module 63. Meanwhile, the region of the wiring substrate 10 where the mesh wiring layer 20 is disposed is located between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. Although not shown, the mesh wiring layer 20 may be disposed on the second surface 11b of the substrate 11. That is, the mesh wiring layer 20 may be provided closer to the display device 61 than the substrate 11. Details of such a wiring substrate 10 will be described later.

[0041] The second transparent adhesive layer 96 is an adhesive layer that directly or indirectly adheres the display device 61 to the wiring substrate 10. This second transparent adhesive layer 96 is located on the second surface 11b side of the substrate 11. Like the first transparent adhesive layer 95, the second transparent adhesive layer 96 has optical transparency and may be an OCA (Optical Clear Adhesive) layer. The material of the second transparent adhesive layer 96 may be an acrylic resin, a silicone resin, a urethane resin, or the like. In particular, the second transparent adhesive layer 96 may contain an acrylic resin. This substantially eliminates the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, thereby more reliably suppressing reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0042] The second transparent adhesive layer 96 may have a transmittance of 85% or more, preferably 90% or more, for visible light (light having a wavelength of 400 nm or more and 700 nm or less). There is no particular upper limit to the visible light transmittance of the second transparent adhesive layer 96, but it may be, for example, 100% or less. By setting the visible light transmittance of the second transparent adhesive layer 96 to be within the above range, the transparency of the laminate 70 for an image display device can be increased, and the display device 61 of the image display device 60 can be made easier to view.

[0043] In this image display device 60, the difference in refractive index between the substrate 11 and the first transparent adhesive layer 95 is 0.05 or less, and preferably 0.02 or less. The difference in refractive index between the substrate 11 and the second transparent adhesive layer 96 is 0.05 or less, and preferably 0.02 or less. The difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96 is preferably 0.05 or less, and more preferably 0.02 or less. For example, if the first transparent adhesive layer 95 and the second transparent adhesive layer 96 are made of acrylic resins with refractive indices of 1.49, the refractive index of the substrate 11 is set to 1.45 or more and 1.54 or less. Examples of such materials include fluororesins, silicone-based resins, polyolefin resins, polyester-based resins, acrylic resins, polycarbonate-based resins, polyimide-based resins, and cellulose-based resins.

[0044] Thus, by limiting the difference between the refractive index of the substrate 11 and the refractive index of the first transparent adhesive layer 95 to 0.05 or less, reflection of visible light at the interface B1 between the substrate 11 and the first transparent adhesive layer 95 is suppressed, making the substrate 11 less visible to the naked eye of an observer. Furthermore, by limiting the difference between the refractive index of the substrate 11 and the refractive index of the second transparent adhesive layer 96 to 0.05 or less, reflection of visible light at the interface B2 between the substrate 11 and the second transparent adhesive layer 96 is suppressed, making the substrate 11 less visible to the naked eye of an observer. Furthermore, by limiting the difference between the refractive index of the first transparent adhesive layer 95 and the refractive index of the second transparent adhesive layer 96 to 0.05 or less, reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96 is suppressed. Therefore, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 are less visible to the naked eye of an observer.

[0045] In particular, it is preferable that the material of the first transparent adhesive layer 95 and the material of the second transparent adhesive layer 96 are the same material. This makes it possible to further reduce the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, and to suppress reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0046] In addition, in FIG. 2, the thickness T ３ and the thickness T of the second transparent adhesive layer 96 ４ At least one of the thicknesses is the thickness T of the substrate 11. １ The thickness T of the substrate 11 may be 1.5 times or more, preferably 2 times or more, and more preferably 2.5 times or more. １ The thickness T of the first transparent adhesive layer 95 ３ or the thickness T of the second transparent adhesive layer 96 ４ By making the first transparent adhesive layer 95 or the second transparent adhesive layer 96 sufficiently thick, the first transparent adhesive layer 95 or the second transparent adhesive layer 96 deforms in the thickness direction in the region overlapping with the substrate 11, absorbing the thickness of the substrate 11. This makes it possible to prevent steps from occurring in the first transparent adhesive layer 95 or the second transparent adhesive layer 96 at the periphery of the substrate 11, making it difficult for an observer to recognize the presence of the substrate 11.

[0047] Thickness T of the first transparent adhesive layer 95 ３ and the thickness T of the second transparent adhesive layer 96 ４At least one of the thicknesses is the thickness T of the substrate 11. １ The thickness T ３ or the thickness T of the second transparent adhesive layer 96 ４ The thickness of the image display device 60 as a whole can be reduced.

[0048] In addition, in FIG. 2, the thickness T ３ is the thickness T of the second transparent adhesive layer 96 ４ As described above, the first transparent adhesive layer 95 is located on the first surface 11a side of the substrate 11 of the wiring board 10. In addition, the mesh wiring layer 20 is disposed on the first surface 11a of the substrate 11 of the wiring board 10. Therefore, there is a possibility that unevenness will be formed on the surface of the first transparent adhesive layer 95 due to the unevenness formed by the mesh wiring layer 20. In contrast, the thickness T ３ is the thickness T of the second transparent adhesive layer 96 ４ By making the thickness of the first transparent adhesive layer 95 thicker than the thickness of the first transparent adhesive layer 95 , it is possible to prevent the formation of irregularities on the surface of the first transparent adhesive layer 95 , and to make the surface of the first transparent adhesive layer 95 smooth.

[0049] Thickness T of the first transparent adhesive layer 95 ３ and the thickness T of the second transparent adhesive layer 96 ４ The difference between the thickness T and the thickness T is preferably 100 μm or less. As described above, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 may be OCA layers. Therefore, residual stress that may be generated in the OCA layer when the OCA layer is produced may generate tensile stress in the first transparent adhesive layer 95 and the second transparent adhesive layer 96, which acts to shrink the first transparent adhesive layer 95 and the second transparent adhesive layer 96. This tensile stress is generated by the thickness T of the first transparent adhesive layer 95. ３ or the thickness T of the second transparent adhesive layer 96 ４ If the difference between the tensile stress generated in the first transparent adhesive layer 95 and the tensile stress generated in the second transparent adhesive layer 96 becomes large, warping of the wiring substrate 10 may occur. ３and the thickness T of the second transparent adhesive layer 96 ４ By making the difference between the first and second transparent adhesive layers 95 and 96 100 μm or less, it is possible to reduce the difference between the tensile stress generated in the first transparent adhesive layer 95 and the tensile stress generated in the second transparent adhesive layer 96. This makes it possible to reduce warping of the wiring substrate 10 caused by the difference between the tensile stress generated in the first transparent adhesive layer 95 and the tensile stress generated in the second transparent adhesive layer 96.

[0050] In FIG. 2, the thickness T ３ and the thickness T of the second transparent adhesive layer 96 ４ In this case, the thickness T ３ and the thickness T of the second transparent adhesive layer 96 ４ are the thickness T of the substrate 11, respectively. １ The thickness T ３ and the thickness T of the second transparent adhesive layer 96 ４ The sum of (T ３ +T ４ ) is the thickness T of the substrate 11 １ In this way, the thickness T １ , the thickness T of the first transparent adhesive layer 95 and the second transparent adhesive layer 96 ３ , T ４ By making the total of the thicknesses of the first and second transparent adhesive layers 95 and 96 sufficiently thick, the first and second transparent adhesive layers 95 and 96 deform (shrink) in the thickness direction in the region overlapping with the substrate 11. As a result, the first and second transparent adhesive layers 95 and 96 absorb the thickness of the substrate 11. This makes it possible to prevent steps from occurring in the first and second transparent adhesive layers 95 and 96 at the periphery of the substrate 11, making it difficult for an observer to recognize the presence of the substrate 11.

[0051] Thickness T of the first transparent adhesive layer 95 ３ and the thickness T of the second transparent adhesive layer 96 ４ and are the same, the thickness T ３ and the thickness T of the second transparent adhesive layer 96 ４ are the thickness T of the substrate 11, respectively. １The thickness T ３ , T ４ The thickness of the image display device 60 as a whole can be reduced.

[0052] Specifically, the thickness T of the substrate 11 １ The thickness T of the substrate 11 may be, for example, 2.0 μm or more, 10 μm or more, and preferably 15 μm or more. １ By setting the thickness T of the substrate 11 to 2.0 μm or more, the strength of the wiring substrate 10 can be maintained, and the first directional wiring 21 and the second directional wiring 22 of the mesh wiring layer 20, which will be described later, can be made less likely to deform. １ The thickness T of the substrate 11 may be, for example, 200 μm or less, or 50 μm or less, and is preferably 25 μm or less. １ By setting the thickness T of the substrate 11 to 200 μm or less, it is possible to prevent the occurrence of a step in the first transparent adhesive layer 95 and the second transparent adhesive layer 96 at the periphery of the substrate 11, and to make it difficult for an observer to recognize the presence of the substrate 11. １ By setting the thickness to 50 μm or less, the occurrence of steps in the first transparent adhesive layer 95 and the second transparent adhesive layer 96 at the periphery of the substrate 11 can be further suppressed, making it more difficult for an observer to recognize the presence of the substrate 11.

[0053] Thickness T of the first transparent adhesive layer 95 ３ The thickness T of the first transparent adhesive layer 95 may be, for example, 15 μm or more, and is preferably 20 μm or more. ３ The thickness T of the first transparent adhesive layer 95 may be, for example, 500 μm or less, preferably 300 μm or less, and more preferably 250 μm or less. ３ Since the thickness T of the first transparent adhesive layer 95 is 500 μm or less, ３ The thickness T of the first transparent adhesive layer 95 does not become too thick, and the overall thickness of the image display device 60 can be reduced. ３ By making the thickness 300 μm or less, the overall thickness of the image display device 60 can be further reduced.

[0054] Thickness T of the second transparent adhesive layer 96 ４ The thickness T of the second transparent adhesive layer 96 may be, for example, 15 μm or more, and is preferably 20 μm or more. ４ The thickness T of the second transparent adhesive layer 96 may be, for example, 500 μm or less, preferably 300 μm or less, and more preferably 250 μm or less. ４ Since the thickness T of the second transparent adhesive layer 96 is 500 μm or less, ４ The thickness T of the second transparent adhesive layer 96 does not become too thick, and the overall thickness of the image display device 60 can be reduced. ４ By making the thickness 300 μm or less, the overall thickness of the image display device 60 can be further reduced.

[0055] As described above, the laminate 70 for an image display device is composed of the wiring substrate 10, the first transparent adhesive layer 95 having an area larger than that of the substrate 11 of the wiring substrate 10, and the second transparent adhesive layer 96 having an area larger than that of the substrate 11. In the present embodiment, such a laminate 70 for an image display device is also provided.

[0056] Referring again to FIG. 2 , the cover glass 75 is disposed directly or indirectly on the first transparent adhesive layer 95. The cover glass 75 is located on the positive side of the first transparent adhesive layer 95 in the Z direction and is disposed on the decorative layer 74. The cover glass 75 is a light-transmitting glass member. The cover glass 75 is plate-shaped and may have a rectangular shape in a plan view. The thickness of the cover glass 75 may be, for example, 200 μm to 1000 μm, and preferably 300 μm to 700 μm. The length of the cover glass 75 in the longitudinal direction (Y direction) may be, for example, 20 mm to 500 mm, and preferably 100 mm to 200 mm. The length of the cover glass 75 in the lateral direction (X direction) may be, for example, 20 mm to 500 mm, and preferably 50 mm to 100 mm.

[0057] At least a portion of the decorative layer 74 is disposed on the first transparent adhesive layer 95. The decorative layer 74 may be a decorative film. For example, the decorative layer 74 has an opening in all or part of the portion that overlaps with the display area of ​​the display device 61 when viewed from the viewer's side, and blocks light from the portion other than the display area. In other words, the decorative layer 74 is disposed so as to cover the edge of the display device 61 when viewed from the viewer's side.

[0058] 1, the shape of the image display device 60 is a substantially rectangular shape as a whole in a plan view, with its longitudinal direction parallel to the Y direction and its lateral direction parallel to the X direction. ４ The length L of the image display device 60 in the short side direction (X direction) can be selected, for example, in the range of 20 mm to 500 mm, preferably 100 mm to 200 mm. ５ The distance can be selected, for example, within a range of 20 mm to 500 mm, preferably 50 mm to 100 mm. The planar shape of the image display device 60 may be a rectangle with rounded corners.

[0059] Next, the configuration of the wiring board will be described with reference to Figures 3 to 6. Figures 3 to 6 are diagrams showing the wiring board according to this embodiment.

[0060] The wiring substrate 10 according to this embodiment is a substrate used in the image display device 60 described above (see FIGS. 1 and 2). The wiring substrate 10 can be disposed on the light-emitting surface 64 side of the display device 61, between a first transparent adhesive layer 95 and a second transparent adhesive layer 96 (see FIG. 2). As shown in FIG. 3, such a wiring substrate 10 includes a transparent substrate 11 and a mesh wiring layer 20 disposed on the substrate 11, as described above. The mesh wiring layer 20 is electrically connected to a power supply unit 40.

[0061] The shape of the substrate 11 is approximately rectangular in plan view. In the illustrated example, its longitudinal direction is parallel to the X direction, and its lateral direction is parallel to the Y direction. The substrate 11 is transparent and has an approximately flat plate shape, and its thickness is approximately uniform overall. The length L of the substrate 11 in the longitudinal direction (Y direction) of the image display device 60 is １The length L of the substrate 11 in the short-side direction (X direction) of the image display device 60 (see FIGS. 1 and 3) can be selected, for example, in the range of 10 mm to 200 mm. ２ (See FIG. 1) can be selected, for example, in the range of 3 mm to 100 mm. The planar shape of the substrate 11 may be a rectangle with rounded corners.

[0062] The material of the substrate 11 may be any material that is transparent in the visible light range and electrically insulating. The material of the substrate 11 is preferably an organic insulating material such as a polyester resin, an acrylic resin, a polycarbonate resin, a polyimide resin, a polyolefin resin, a cellulose resin, or a fluororesin material. The polyester resin may be polyethylene terephthalate or the like. The acrylic resin may be polymethyl methacrylate or the like. The polyolefin resin may be a cycloolefin polymer or the like. The cellulose resin may be triacetyl cellulose or the like. The fluororesin material may be PTFE, PFA or the like. For example, the material of the substrate 11 may be an organic insulating material such as a cycloolefin polymer (e.g., ZF-16 manufactured by Nippon Zeon Co., Ltd.) or a polynorbornene polymer (manufactured by Sumitomo Bakelite Co., Ltd.). Furthermore, the material of the substrate 11 may be glass, ceramics, or the like, appropriately selected depending on the application. Although the substrate 11 is illustrated as being made up of a single layer, the present invention is not limited to this and may have a structure in which multiple base materials or layers are stacked. Furthermore, the substrate 11 may be a film-like member or a plate-like member.

[0063] The dielectric loss tangent of the substrate 11 is preferably 0.002 or less. When the dielectric loss tangent of the substrate 11 is in the above range, particularly when the electromagnetic waves (e.g., millimeter waves) transmitted and received by the mesh wiring layer 20 are high frequency, the gain loss (reduction in sensitivity) associated with the transmission and reception of the electromagnetic waves can be reduced.

[0064] The dielectric constant of the substrate 11 is preferably 2 or more and 10 or less. Having a dielectric constant of 2 or more allows for a wider range of material options for the substrate 11. Furthermore, having a dielectric constant of 10 or less for the substrate 11 allows for reduced gain loss during transmission and reception of electromagnetic waves. That is, when the dielectric constant of the substrate 11 increases, the thickness of the substrate 11 has a greater effect on the propagation of electromagnetic waves. Furthermore, if there is an adverse effect on the propagation of electromagnetic waves, the dielectric loss tangent of the substrate 11 increases, which can result in increased gain loss during transmission and reception of electromagnetic waves. In contrast, having a dielectric constant of 10 or less for the substrate 11 allows for reduced effect of the thickness of the substrate 11 on the propagation of electromagnetic waves. Therefore, the gain loss during transmission and reception of electromagnetic waves can be reduced. In particular, when the electromagnetic waves (e.g., millimeter waves) transmitted and received by the mesh wiring layer 20 are high frequency, the gain loss during transmission and reception of electromagnetic waves can be reduced.

[0065] The dielectric loss tangent and relative dielectric constant of the substrate 11 can be measured in accordance with IEC 62562. Specifically, first, a test piece is prepared by cutting out a portion of the substrate 11 where the mesh wiring layer 20 is not formed. The dimensions of the test piece are a width of 10 mm to 20 mm and a length of 50 mm to 100 mm. Next, the dielectric loss tangent or relative dielectric constant is measured in accordance with IEC 62562.

[0066] In this embodiment, the substrate 11 is transparent. In this specification, "transparent" means that the transmittance of visible light (light having a wavelength of 400 nm or more and 700 nm or less) is 85% or more. The substrate 11 may have a visible light transmittance of 85% or more, and preferably 90% or more. There is no particular upper limit to the visible light transmittance of the substrate 11, but it may be, for example, 100% or less. By setting the visible light transmittance of the substrate 11 to be within the above range, the transparency of the wiring substrate 10 can be increased, and the display device 61 of the image display device 60 can be more easily viewed.

[0067] In this embodiment, the mesh wiring layer 20 is made up of an antenna pattern that functions as an antenna. This mesh wiring layer 20 may be configured as an array antenna. When the mesh wiring layer 20 is configured as an array antenna in this way, it is possible to improve the millimeter wave antenna performance for transmitting and receiving millimeter waves with high linearity. Note that an array antenna is an antenna in which multiple antenna elements (radiating elements) are regularly arranged and in which the amplitude and phase of the excitation of the elements can be independently controlled.

[0068] As shown in Fig. 3, a plurality of mesh wiring layers 20 are formed on the substrate 11. It is preferable that four or more mesh wiring layers 20 are provided. In the illustrated example, four mesh wiring layers 20 are formed on the substrate 11 (see Fig. 1). Also, as shown in Fig. 3, the mesh wiring layers 20 may not be present on the entire surface of the substrate 11, but may be present only in a partial region on the substrate 11. Each mesh wiring layer 20 may have the same shape. In this case, each mesh wiring layer 20 has a length (distance in the Y direction) L of a tip side portion 20b described later. ａ Error and width (X direction distance) W ａ It is preferable that the errors of the above are within 10%. This can effectively improve the performance of the millimeter wave antenna.

[0069] The mesh wiring layer 20 has a base end portion (transmission portion) 20a on the power supply unit 40 side and a tip end portion (transmission / reception portion) 20b connected to the base end portion 20a. The base end portion 20a is connected to the power supply unit 40. In this case, the base end portion (transmission portion) 20a may be configured as a microstrip line or a coplanar line. The base end portion 20a and the tip end portion 20b each have a substantially rectangular shape in a plan view. In this case, the length (distance in the Y direction) of the tip end portion 20b is substantially the same as the length (distance in the Y direction) of the base end portion 20a, and the width (distance in the X direction) of the tip end portion 20b is wider than the width (distance in the X direction) of the base end portion 20a.

[0070] The tip end portion 20b of the mesh wiring layer 20 corresponds to a predetermined frequency band. That is, the tip end portion 20b has a length (distance in the Y direction) Lａ The length L of the distal end portion 20b corresponds to a specific frequency band. ａ The length of the mesh wiring layer 20 becomes longer. In addition to a millimeter wave antenna, the mesh wiring layer 20 may also be compatible with any of a telephone antenna, a Wi-Fi antenna, a 3G antenna, a 4G antenna, a 5G antenna, an LTE antenna, a Bluetooth (registered trademark) antenna, an NFC antenna, etc. The lengths of the multiple tip portions 20b may be different from each other and each may correspond to a different frequency band. Alternatively, if the wiring board 10 does not have a radio wave transmission / reception function, each mesh wiring layer 20 may perform functions such as a hovering function, fingerprint authentication, a heater, noise reduction (shielding), etc. The hovering function refers to a function that allows the user to operate the display without directly touching it.

[0071] In the illustrated example, the tip portion 20b has a longitudinal direction parallel to the X direction and a lateral direction parallel to the Y direction. Alternatively, the tip portion 20b may have a longitudinal direction parallel to the Y direction and a lateral direction parallel to the X direction. The length L of the tip portion 20b in the Y direction ａ The width W of the tip portion 20b in the X direction can be selected, for example, in the range of 1 mm to 100 mm. ａ In particular, when the mesh wiring layer 20 is a millimeter wave antenna, the length L of the tip side portion 20b can be selected within a range of, for example, 1 mm or more and 100 mm or less. ａ When the mesh wiring layer 20 is a millimeter wave antenna, the length L of the tip side portion 20b can be selected in the range of 1 mm or more, more preferably 1.5 mm or more. ａ can be selected in the range of 10 mm or less, more preferably 5 mm or less.

[0072] The distance between the mesh wiring layers 20 is preferably 0.2 mm or more and 5 mm or less. ２０ｂ The distance D between the tip end portions 20b (see FIG. 3) is preferably 0.2 mm or more and 5 mm or less. ２０ｂWhen the distance D between the tip side portions 20b is 0.2 mm or more, unintended interference of electromagnetic waves between the antenna elements can be suppressed. ２０ｂ By making the distance D between the tip side portions 20b equal to or less than 5 mm, it is possible to reduce the size of the entire array antenna formed by the mesh wiring layer 20. For example, when the mesh wiring layer 20 is a millimeter wave antenna of 28 GHz, the distance D between the tip side portions 20b is equal to or less than 5 mm. ２０ｂ In addition, when the mesh wiring layer 20 is a millimeter wave antenna of 60 GHz, the distance D between the tip side portions 20b may be 3.5 mm. ２０ｂ may be 1.6 mm.

[0073] 4, the mesh wiring layer 20 has a pattern shape in which metal wires are arranged in a lattice or mesh shape. This pattern shape is repeatedly arranged in the X direction and the Y direction. That is, the mesh wiring layer 20 has a pattern shape composed of a portion (first-directional wiring 21 described later) extending in a first direction (e.g., Y direction) and a portion (second-directional wiring 22 described later) extending in a second direction (e.g., X direction).

[0074] The mesh wiring layer 20 has a plurality of wires. Specifically, the mesh wiring layer 20 has a plurality of first-directional wires (wires) 21 and a plurality of second-directional wires (wires) 22 connecting the plurality of first-directional wires 21. The plurality of first-directional wires 21 and the plurality of second-directional wires 22 are arranged to protrude above the substrate 11. The plurality of first-directional wires 21 and the plurality of second-directional wires 22 are integrated as a whole to form a lattice or mesh-like shape. Each first-directional wire 21 extends in the longitudinal direction (Y direction) of the mesh wiring layer 20. Each second-directional wire extends linearly in the width direction (X direction) of the mesh wiring layer 20. Note that the first-directional wires 21 and the second-directional wires 22 may extend in a direction that is not parallel to either the X direction or the Y direction.

[0075] In the mesh wiring layer 20, openings 23 are formed by being surrounded by wires. That is, in the mesh wiring layer 20, a plurality of openings 23 are formed by being surrounded by adjacent first directional wires 21 and adjacent second directional wires 22. The transparent substrate 11 is exposed from each opening 23. This allows the transparency of the wiring substrate 10 as a whole to be increased.

[0076] The planar shape of each opening 23 is approximately square in plan view. That is, the first directional wirings 21 and the second directional wirings 22 are arranged at equal intervals. The first directional wirings 21 are arranged at equal intervals with a pitch P １ The pitch P may be, for example, in the range of 0.01 mm to 10 mm, or in the range of 500 μm to 10 mm. ２ The pitch P of the first directional wirings 21 may be in the range of 0.01 mm or more and 10 mm or in the range of 500 μm or more and 10 mm or less. In this way, by arranging the plurality of first directional wirings 21 and the plurality of second directional wirings 22 at equal intervals, the size of the openings 23 in the mesh wiring layer 20 does not vary, and the mesh wiring layer 20 can be made difficult to see with the naked eye. In addition, the pitch P of the first directional wirings 21 may be in the range of 0.01 mm or more and 10 mm or less. In this way, the plurality of first directional wirings 21 and the plurality of second directional wirings 22 are arranged at equal intervals, so that the size of the openings 23 in the mesh wiring layer 20 does not vary, and the mesh wiring layer 20 can be made difficult to see with the naked eye. １ is the pitch P of the second directional wiring 22 ２ Therefore, as described above, each opening 23 has a substantially square shape in a plan view, and the transparent substrate 11 is exposed from each opening 23. Therefore, by increasing the area of ​​each opening 23, the transparency of the wiring substrate 10 as a whole can be increased. Note that the length L of one side of each opening 23 is ３ The width of the first directional wirings 21 and the second directional wirings 22 may be, for example, in the range of 0.01 mm to 10 mm, or in the range of 500 μm to 10 mm. Note that although the first directional wirings 21 and the second directional wirings 22 are perpendicular to each other, this is not limitative and they may intersect at an acute angle or an obtuse angle. Furthermore, it is preferable that the shape of the openings 23 be the same shape and size over the entire surface, but it is not necessary that the shape be uniform over the entire surface, and the shape may vary depending on the location.

[0077] As shown in FIG. 5 , each first directional wiring 21 has a cross section perpendicular to its longitudinal direction (X-direction cross section) that is substantially rectangular or square. In this case, the cross-sectional shape of the first directional wiring 21 is substantially uniform along the longitudinal direction (Y-direction) of the first directional wiring 21. As shown in FIG. 6 , each second directional wiring 22 has a cross section perpendicular to its longitudinal direction (Y-direction cross section) that is substantially rectangular or square, and has substantially the same shape as the cross-sectional shape (X-direction cross section) of the first directional wiring 21 described above. In this case, the cross-sectional shape of the second directional wiring 22 is substantially uniform along the longitudinal direction (X-direction) of the second directional wiring 22. The cross-sectional shapes of the first directional wiring 21 and the second directional wiring 22 do not necessarily have to be substantially rectangular or square. For example, the cross-sectional shapes of the first directional wiring 21 and the second directional wiring 22 may be approximately trapezoidal in that the front side (positive side in the Z direction) is narrower than the back side (negative side in the Z direction), or may be shaped such that the side surfaces on both sides in the longitudinal direction are curved.

[0078] In this embodiment, the line width W of the first direction wiring 21 １ (see FIG. 5) and the line width W ２ (See FIG. 6) is not particularly limited and can be appropriately selected depending on the application. １ is the width (distance in the X direction) in a cross section perpendicular to the longitudinal direction, and the line width W of the second directional wiring 22 ２ is the width (distance in the Y direction) in a cross section perpendicular to the longitudinal direction. For example, the line width W １ The width W of the second direction wiring 22 can be selected in the range of 0.1 μm or more and 5.0 μm or less, preferably 3.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less. ２ can be selected in the range of 0.1 μm or more and 5.0 μm or less, preferably 3.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less.

[0079] Height H of the first directional wiring 21 １ (See FIG. 5) and the height H ２ (See FIG. 6) is not particularly limited and can be appropriately selected depending on the application.１ and the height H of the second direction wiring 22 ２ are the lengths in the Z direction. １ and the height H of the second direction wiring 22 ２ The height H of the first directional wiring 21 can be selected within a range of, for example, 0.1 μm or more, and is preferably 0.2 μm or more. １ and the height H of the second direction wiring 22 ２ can be selected, for example, in the range of 5.0 μm or less, and is preferably 2.0 μm or less.

[0080] The material of the first directional wiring 21 and the second directional wiring 22 may be any conductive metal material. 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 such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals. Furthermore, the first directional wiring 21 and the second directional wiring 22 may be a plating layer formed by electrolytic plating.

[0081] The overall aperture ratio At of the mesh wiring layer 20 may be, for example, in the range of 87% or more and less than 100%. By setting the overall aperture ratio At of the mesh wiring layer 20 in this range, the conductivity and transparency of the wiring substrate 10 can be ensured. The overall aperture ratio At of the mesh wiring layer 20 is preferably 95% or more and less than 100%, and more preferably 98% or more and less than 100%. This allows the transparency of the wiring substrate 10 to be increased while ensuring the conductivity of the wiring substrate 10. The aperture ratio refers to the percentage (%) of the area of ​​the open region in a unit area of ​​a predetermined region (e.g., the entire mesh wiring layer 20). The open region refers to a region where no metal parts such as the first directional wiring 21 and the second directional wiring 22 are present and the substrate 11 is exposed.

[0082] Here, first isolated wirings (isolated wirings) 35 and second isolated wirings (isolated wirings) 36 that are electrically independent from the first directional wirings (wirings) 21 and the second directional wirings (wirings) 22 are provided within the opening 23. In this embodiment, a plurality of first isolated wirings 35 and a plurality of second isolated wirings 36 are provided within the opening 23. The first isolated wirings 35 and the second isolated wirings 36 are each electrically independent from the mesh wiring layer 20 (the first directional wirings 21 and the second directional wirings 22).

[0083] In this case, the first isolated wiring 35 extends parallel to the first directional wiring 21. Furthermore, the second isolated wiring 36 extends parallel to the second directional wiring 22. In this way, the first isolated wiring 35 and the second isolated wiring 36 extend parallel to the first directional wiring 21 or the second directional wiring 22, so that the mesh wiring layer 20 arranged on the substrate 11 can be made even less visible.

[0084] As described above, the first isolated wiring 35 and the second isolated wiring 36 are electrically independent from the first directional wiring 21 and the second directional wiring 22, respectively. １１ The distance L between the second direction wiring 22 and the first isolated wiring 35 is preferably 4.0 μm or more and 400 μm or less. １２ The distance L is preferably 4.0 μm or more and 400 μm or less. １１ (distance L １２ ) is 4.0 μm or more, it is possible to effectively prevent the first directional wiring 21 (second directional wiring 22) and the second isolated wiring 36 (first isolated wiring 35) from being electrically connected to each other. １１ (distance L １２ ) is 400 μm or less, the first directional wiring 21 (second directional wiring 22) can be made inconspicuous. １１ (distance L １２ ) is 400 μm or less, the first direction wirings 21 (second direction wirings 22) can be made unclear. This makes it possible to make the mesh wiring layer 20 less visible on the surface of the image display device 60, and makes it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye.

[0085] The first isolated wirings 35 are separated from each other by the notches 37. In this case, the length L of the first isolated wirings 35 is １３ The length L of the notch 37 is preferably 5.0 μm or more and 50 μm or less. １４ The length L of the second isolated wirings 36 is preferably 4.0 μm or more and 400 μm or less. The second isolated wirings 36 are separated from each other via the notches 38. In this case, the length L of the second isolated wirings 36 is preferably 4.0 μm or more and 400 μm or less. １５ The length L of the notch 37 is preferably 5.0 μm or more and 50 μm or less. １６ The length L of the first isolated wiring 35 is preferably 4.0 μm or more and 400 μm or less. １３ (The length L of the second isolated wiring 36 １５ By making the length L of the first isolated wiring 35 5.0 μm or more, the first direction wiring 21 (second direction wiring 22) can be made less noticeable, and the mesh wiring layer 20 can be made less visible to the user of the image display device 60 with the naked eye. １３ (The length L of the second isolated wiring 36 １５ By making the length L of the notch 37 50 μm or less, it is possible to prevent the overall aperture ratio At of the mesh wiring layer 20 from decreasing, and the transparency of the wiring substrate 10 can be increased. １４ (Length L of the notch 38 １６ When the length L of the notch 37 is 4.0 μm or more, the overall aperture ratio At of the mesh wiring layer 20 can be increased, and the transparency of the wiring substrate 10 can be increased. １４ (Length L of the notch 38 １６ ) is 400 μm or less, the first direction wiring 21 (second direction wiring 22) can be made inconspicuous, and the mesh wiring layer 20 can be made difficult for a user of the image display device 60 to recognize with the naked eye.

[0086] The plurality of first isolated wirings 35 are arranged in the opening 23 along the X direction at equal intervals, with a pitch P １１ The second isolated wirings 36 are arranged in the opening 23 along the Y direction at equal intervals, and the pitch P １２The pitch P may be, for example, in the range of 50 μm to 500 μm. １１ (Pitch P １２ By making the pitch P ) 50 μm or more, the overall aperture ratio At of the mesh wiring layer 20 can be increased, and the transparency of the wiring substrate 10 can be increased. １１ (Pitch P １２ ) is 500 μm or less, the first direction wirings 21 (second direction wirings 22) can be made inconspicuous, making it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye. Also, as in this embodiment, by arranging the plurality of first isolated wirings 35 and the plurality of second isolated wirings 36 at equal intervals, the first isolated wirings 35 and the second isolated wirings 36 can be made difficult to recognize with the naked eye. Furthermore, the transparent substrate 11 is exposed between the first isolated wirings 35 and the second isolated wirings 36. This makes it possible to increase the transparency of the wiring substrate 10 as a whole. Note that within the opening 23, the pitch P of the first isolated wirings 35 is １１ is the pitch P of the second isolated wiring 36 １２ In addition, the first isolated wirings 35 and the second isolated wirings 36 are perpendicular to each other, but are not limited to this and may intersect each other at an acute angle or an obtuse angle.

[0087] As shown in FIG. 5 , each first isolated wiring 35 has a substantially rectangular or square cross section (X-direction cross section) perpendicular to its longitudinal direction. In this case, the cross-sectional shape of the first isolated wiring 35 is substantially uniform along the longitudinal direction (Y-direction) of the first isolated wiring 35. As shown in FIG. 6 , each second isolated wiring 36 has a substantially rectangular or square cross section (Y-direction cross section) perpendicular to its longitudinal direction, which is substantially the same as the cross-sectional shape (X-direction cross section) of the first isolated wiring 35 described above. In this case, the cross-sectional shape of the second isolated wiring 36 is substantially uniform along the longitudinal direction (X-direction) of the second isolated wiring 36. The cross-sectional shapes of the first isolated wiring 35 and the second isolated wiring 36 do not necessarily have to be substantially rectangular or square. For example, the cross-sectional shapes of the first isolated wiring 35 and the second isolated wiring 36 may be substantially trapezoidal, with the front side (positive side in the Z-direction) narrower than the back side (negative side in the Z-direction), or may have curved side surfaces on both widthwise sides.

[0088] In this embodiment, the line width W of the first isolated wiring 35 １１ (See FIG. 5) and the line width W １２ (See FIG. 6) is not particularly limited and can be appropriately selected depending on the application. １１ and the line width W of the second isolated wiring 36 １２ is the line width W of the first direction wiring 21 １ and the line width W of the second direction wiring 22 ２ Here, the line width W of the first isolated wiring 35 is preferably equal to １１ is the width (distance in the X direction) in a cross section perpendicular to the longitudinal direction, and the line width W １２ is the width (distance in the Y direction) in a cross section perpendicular to the longitudinal direction. １１ The width W of the second isolated wiring 36 can be selected, for example, from 0.1 μm to 5.0 μm, preferably 3.0 μm or less, and more preferably 0.2 μm to 2.0 μm. １２ The line width W can be selected, for example, from 0.1 μm to 5.0 μm, preferably 3.0 μm or less, and more preferably 0.2 μm to 2.0 μm. １１ (Line width W １２By making the line width W ) 0.2 μm or more, the first direction wiring 21 (second direction wiring 22) can be made less noticeable, and the mesh wiring layer 20 can be made less visible to the user of the image display device 60 with the naked eye. １１ (Line width W １２ By making the thickness θ 3.0 μm or less, the overall aperture ratio At of the mesh wiring layer 20 can be increased, and the transparency of the wiring substrate 10 can be increased.

[0089] Height H of the first isolated wiring 35 １１ (See FIG. 5) and the height H １２ (See FIG. 6) is not particularly limited and can be appropriately selected depending on the application. １１ and the height H of the second isolated wiring 36 １２ are the lengths in the Z direction. １１ and the height H of the second isolated wiring 36 １２ The height H of the first isolated wiring 35 can be selected within a range of, for example, 0.1 μm or more, and is preferably 0.2 μm or more. １１ and the height H of the second isolated wiring 36 １２ can be selected, for example, in the range of 5.0 μm or less, and is preferably 2.0 μm or less.

[0090] The material of the first isolated wires 35 and the second isolated wires 36 may be the same as the material of the first directional wires 21 and the second directional wires 22 described above. That is, the material of the first isolated wires 35 and the second isolated wires 36 may be any conductive metal material. In the present embodiment, the material of the first isolated wires 35 and the second isolated wires 36 is copper, but this is not limited to this. The material of the first isolated wires 35 and the second isolated wires 36 may be, for example, a metal material such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals. Furthermore, the first isolated wires 35 and the second isolated wires 36 may be a plating layer formed by electrolytic plating.

[0091] The area ratio of the first isolated wiring 35 and the second isolated wiring 36 in the opening 23 is preferably 0.1% or more and 0.3% or less. When the area ratio is 0.1% or more, the first directional wiring 21 (second directional wiring 22) can be made less noticeable, making it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye. Furthermore, when the area ratio is 0.3% or less, the overall aperture ratio At of the mesh wiring layer 20 can be increased, and the transparency of the wiring substrate 10 can be increased. The area ratio refers to the proportion (%) of the area of ​​the first isolated wiring 35 and the second isolated wiring 36 to the area of ​​the opening 23.

[0092] Although not shown, a protective layer may be formed on the first surface 11a of the substrate 11 so as to cover the mesh wiring layer 20. The protective layer protects the mesh wiring layer 20 and is formed so as to cover at least the mesh wiring layer 20 of the substrate 11. Examples of materials that can be used for the protective layer include acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate, modified resins thereof, copolymers thereof, polyvinyl resins such as polyester, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, and polyvinyl butyral, copolymers thereof, polyurethane, epoxy resin, polyamide, and chlorinated polyolefin, and other colorless and transparent insulating resins.

[0093] 3 again, a power supply unit 40 is electrically connected to the mesh wiring layer 20. This power supply unit 40 is made of a substantially rectangular conductive thin plate member. 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.

[0094] The power supply unit 40 is disposed at the longitudinal end (the end on the negative Y-side) of the substrate 11. The power supply unit 40 may be made of a metal such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing any of these metals.

[0095] When the wiring board 10 is incorporated into the image display device 60 (see FIGS. 1 and 2 ), the power supply unit 40 is electrically connected to the communication module 63 of the image display device 60 via the power supply line 85. Note that although the power supply unit 40 is provided on the substrate 11, this is not limiting, and part or all of the power supply unit 40 may be located outside the periphery of the substrate 11. Furthermore, the power supply unit 40 may be configured to be flexible so that it can wrap around the side or back of the image display device 60. In this case, the power supply unit 40 may be electrically connected to the communication module 63 on the side or back of the image display device 60.

[0096] The mesh wiring layer 20 is electrically connected to the power supply portion 40 on the positive side in the Y direction. In this case, the power supply portion 40 is formed integrally with the mesh wiring layer 20. The thickness T of the power supply portion 40 ５ (Z-direction distance, see FIG. 6) is the height H of the first direction wiring 21 １ (See FIG. 5) and the height H ２ (see FIG. 6), and can be selected, for example, in the range of 0.1 μm to 5.0 μm.

[0097] Next, the configuration of the module will be described with reference to Fig. 7. Fig. 7 is a diagram showing the module according to this embodiment.

[0098] 7 , module 80A includes the above-described wiring board 10 and power supply line 85 electrically connected to power supply unit 40 via anisotropic conductive film 85c. As described above, when module 80A is incorporated into image display device 60, power supply unit 40 of wiring board 10 is electrically connected to communication module 63 of image display device 60 via power supply line 85.

[0099] The power supply line 85 is pressure-bonded to the wiring board 10 via an anisotropic conductive film (ACF) 85c. The anisotropic conductive film 85c contains a resin material such as acrylic resin or epoxy resin, and conductive particles 85d. In the illustrated example, the anisotropic conductive film 85c covers a portion of the power supply unit 40. This can prevent corrosion of the power supply unit 40.

[0100] The anisotropic conductive film 85c is disposed so as to face the power supply unit 40. Some of the conductive particles 85d are in contact with the power supply unit 40. This electrically connects the power supply line 85 to the power supply unit 40. Note that some of the anisotropic conductive film 85c may be eluted around the power supply line 85 when the power supply line 85 is pressure-bonded to the wiring substrate 10. The particle diameter of the conductive particles 85d may be, for example, approximately 7.0 μm.

[0101] The power supply line 85 may be, for example, a flexible printed circuit board. The power supply line 85 has a base material 85a and a metal wiring portion 85b laminated on the base material 85a. Of these, the base material 85a may contain, for example, a resin material such as polyimide or a liquid crystal polymer. The metal wiring portion 85b may contain, for example, copper. The metal wiring portion 85b is electrically connected to the power supply unit 40 via conductive particles 85d.

[0102] [Methods of Manufacturing Wiring Substrate, Module, and Laminate for Image Display Device] Next, with reference to Figures 8A to 8F, 9A to 9C, and 10A to 10D, methods of manufacturing wiring substrate 10, module 80A, and image display device 60 according to this embodiment will be described. Figures 8A to 8F are cross-sectional views showing the method of manufacturing wiring substrate 10 according to this embodiment. Figures 9A to 9C are cross-sectional views showing the method of manufacturing module 80A according to this embodiment. Figures 10A to 10D are cross-sectional views showing the method of manufacturing image display device 60 according to this embodiment.

[0103] First, a method for manufacturing a wiring board according to this embodiment will be described with reference to FIGS. 8A to 8F.

[0104] 8A, a substrate 11 is prepared, which includes a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The substrate 11 is transparent.

[0105] Next, the mesh wiring layer 20 and the power supply section 40 electrically connected to the mesh wiring layer 20 are formed on the first surface 11 a of the substrate 11 .

[0106] 8B , metal foil 51 is first laminated over substantially the entire first surface 11a of substrate 11. In this embodiment, the thickness of metal foil 51 may be 0.1 μm or more and 5.0 μm or less. In this embodiment, metal foil 51 may contain copper.

[0107] 8C, a photo-curable insulating resist 52 is applied to almost the entire surface of the metal foil 51. As the photo-curable insulating resist 52, for example, an organic resin such as an acrylic resin or an epoxy resin can be used.

[0108] 8D , the insulating layer 54 is formed by photolithography. In this case, the photo-curable insulating resist 52 is patterned by photolithography to form the insulating layer 54 (resist pattern). At this time, the insulating layer 54 is formed so that the metal foil 51 corresponding to the first directional wiring 21, the second directional wiring 22, the first isolated wiring 35, and the second isolated wiring 36 is covered by the insulating layer 54.

[0109] 8E , the metal foil 51 located on the first surface 11 a of the substrate 11 in the portion not covered with the insulating layer 54 is removed. At this time, the metal foil 51 is etched so as to expose the first surface 11 a of the substrate 11 by wet processing using ferric chloride, cupric chloride, a strong acid such as sulfuric acid or hydrochloric acid, persulfate, hydrogen peroxide, an aqueous solution of these, or a combination of these.

[0110] 8F, the insulating layer 54 is removed by wet treatment using a permanganate solution, N-methyl-2-pyrrolidone, an acid or alkaline solution, or dry treatment using oxygen plasma.

[0111] In this manner, a wiring board 10 is obtained, which includes the substrate 11 and the mesh wiring layer 20 provided on the first surface 11a of the substrate 11. In this case, the mesh wiring layer 20 includes first directional wiring 21 and second directional wiring 22. Furthermore, an opening 23 is formed by being surrounded by the first directional wiring 21 and the second directional wiring 22. Then, a first isolated wiring 35 and a second isolated wiring 36 that are electrically independent from the first directional wiring 21 and the second directional wiring 22 are provided within the opening 23. At this time, a power supply unit 40 may be formed by a part of the metal foil. Alternatively, a flat power supply unit 40 may be separately prepared and electrically connected to the mesh wiring layer 20.

[0112] Next, a method for manufacturing the module according to this embodiment will be described with reference to FIGS. 9A to 9C.

[0113] First, as shown in Fig. 9A, the wiring substrate 10 is prepared. At this time, the wiring substrate 10 is fabricated by, for example, the method shown in Figs. 8A to 8F.

[0114] Next, the power supply line 85 is electrically connected to the power supply unit 40 via an anisotropic conductive film 85c containing conductive particles 85d. At this time, first, the anisotropic conductive film 85c and the power supply line 85 are placed on the wiring substrate 10, as shown in FIG. 9B . At this time, the anisotropic conductive film 85c is placed between the power supply line 85 and the power supply unit 40.

[0115] 9C , the power supply line 85 is pressure-bonded to the wiring substrate 10. At this time, pressure and heat are applied to the power supply line 85, thereby pressure-bonding the power supply line 85 to the wiring substrate 10. Then, some of the conductive particles 85d come into contact with the power supply portion 40. In this way, the power supply line 85 is electrically connected to the power supply portion 40. At this time, some of the anisotropic conductive film 85c may dissolve around the power supply line 85.

[0116] In this way, a module 80A is obtained that includes the wiring substrate 10 and the power supply line 85 electrically connected to the power supply section 40 via the anisotropic conductive film 85c containing conductive particles 85d.

[0117] Next, a method for manufacturing the image display device 60 according to this embodiment will be described with reference to FIGS. 10A to 10D.

[0118] 10A , for example, a cover glass 75, a decorative layer 74, and a first transparent adhesive layer 95 are laminated together. A liquid curable adhesive layer composition containing a polymerizable compound may be used as the first transparent adhesive layer 95. This curable adhesive layer composition may contain a polar group-containing monomer. When laminating the cover glass 75, the decorative layer 74, and the first transparent adhesive layer 95 together, the first transparent adhesive layer 95 may be heated to, for example, about 60° C.

[0119] Next, as shown in FIG. 10B, the wiring substrate 10 of the module 80A is laminated on the first transparent adhesive layer 95.

[0120] Next, as shown in FIG. 10C , a second transparent adhesive layer 96 is laminated on the wiring substrate 10. A liquid curable adhesive layer composition containing a polymerizable compound may be used as the second transparent adhesive layer 96. This curable adhesive layer composition may contain a polar group-containing monomer. By laminating the second transparent adhesive layer 96 on the wiring substrate 10 in this manner, the wiring substrate 10 is sandwiched between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. In this manner, a laminate 70 for an image display device is obtained, which includes the first transparent adhesive layer 95, the second transparent adhesive layer 96, and the wiring substrate 10. When laminating the second transparent adhesive layer 96 on the wiring substrate 10, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 may be heated, for example, so that the first transparent adhesive layer 95 and the second transparent adhesive layer 96 reach a temperature of approximately 60°C.

[0121] 10D , the display device 61 is laminated on the second transparent adhesive layer 96. At this time, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 may be heated, for example, so that the first transparent adhesive layer 95 and the second transparent adhesive layer 96 reach a temperature of about 60° C.

[0122] Next, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 are cured using, for example, ultraviolet (UV) rays.

[0123] In this way, the image display device 60 including the laminate for an image display device 70 and the display device 61 laminated on the laminate for an image display device 70 is obtained.

[0124] [Operation of the Present Embodiment] Next, the operation of the present embodiment configured as described above will be described.

[0125] 1 and 2 , the wiring substrate 10 is incorporated into an image display device 60 having a display device 61. At this time, the wiring substrate 10 is placed on the display device 61. The mesh wiring layer 20 of the wiring substrate 10 is electrically connected to the communication module 63 of the image display device 60 via the power supply unit 40 and the power supply line 85. In this way, radio waves of a predetermined frequency can be transmitted and received via the mesh wiring layer 20, and communication can be performed using the image display device 60.

[0126] According to this embodiment, the mesh wiring layer 20 includes first directional wiring 21 and second directional wiring 22. Furthermore, an opening 23 is formed by being surrounded by the first directional wiring 21 and the second directional wiring 22. Then, a first isolated wiring 35 and a second isolated wiring 36 that are electrically independent from the first directional wiring 21 and the second directional wiring 22 are provided within the opening 23. This makes it possible to make the first directional wiring 21 and the second directional wiring 22 less noticeable, and makes it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye.

[0127] Here, in order to increase the transmittance of visible light in the wiring substrate 10, the pitch P of the first directional wiring 21 is １ (The pitch P of the second direction wiring 22 ２ On the other hand, it may be required to increase the pitch P １ In contrast, by providing the first isolated wiring 35 and the second isolated wiring 36 in the opening 23, the pitch P １ Even if the pitch P of the first directional wirings 21 is increased, the first directional wirings 21 and the like can be made inconspicuous. １Even if the thickness of the wiring substrate 10 is increased, the mesh wiring layer 20 can be made difficult to be recognized by the naked eye by a user of the image display device 60. That is, the mesh wiring layer 20 can be made difficult to be recognized by the naked eye by a user of the image display device 60 while increasing the transmittance of visible light in the wiring substrate 10.

[0128] Furthermore, according to this embodiment, the wiring substrate 10 includes a transparent substrate 11 and a mesh wiring layer 20 disposed on the substrate 11. The mesh wiring layer 20 has a conductor portion as a forming portion of an opaque conductive layer and a mesh pattern formed by numerous openings. This ensures the transparency of the wiring substrate 10. As a result, when the wiring substrate 10 is disposed on the display device 61, the display device 61 can be seen through the openings 23 of the mesh wiring layer 20, and the visibility of the display device 61 is not obstructed.

[0129] Next, modified examples of the wiring board will be described.

[0130] Fig. 11 shows a first modified example of the wiring board. The modification shown in Fig. 11 differs in that the planar shape of each opening 23 is a substantially regular hexagon in plan view, but other configurations are substantially the same as those shown in Figs. 1 to 10D described above. In Fig. 11, the same parts as those shown in Figs. 1 to 10D are designated by the same reference numerals, and detailed description thereof will be omitted.

[0131] 11 , the planar shape of each opening 23 is a substantially regular hexagon in plan view. In this modification, the mesh wiring layer 20 includes wiring 25. That is, the opening 23 is formed by being surrounded by the wiring 25. Note that the line width and height of the wiring 25, as well as the material constituting the wiring 25, may be the same as those of the first directional wiring 21.

[0132] In this modification, isolated wirings 39a electrically independent from wirings 25 are provided within opening 23. These isolated wirings 39a extend in three directions within opening 23 so that the shape of the connected ends forms a regular hexagon in plan view. The isolated wirings 39a are separated from one another via notches 39b. The length and pitch of the isolated wirings 39a, as well as the material constituting the isolated wirings 39a, may be the same as those of first isolated wiring 35. The length of notches 39b may be the same as that of notch 37.

[0133] According to this modification, an isolated wiring 39a that is electrically independent from the wiring 25 is provided within the opening 23. This makes it possible to make the wiring 25 less noticeable, and makes it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye.

[0134] Fig. 12 shows a second modified example of the wiring board. The modified example shown in Fig. 12 differs in that the planar shapes of the openings 23 are different from each other, but other configurations are substantially the same as the embodiment shown in Figs. 1 to 11 described above. In Fig. 12, the same parts as those shown in Figs. 1 to 11 are given the same reference numerals, and detailed description thereof will be omitted.

[0135] 12, the planar shapes of the openings 23 are different from one another. Specifically, the planar shapes of the openings 23 are dissimilar hexagons in a planar view. In this case, the wiring 25 is arranged irregularly. Furthermore, in this modification, the isolated wiring 39a is arranged irregularly within the opening 23. Specifically, the isolated wiring 39a extends along a predetermined direction within the opening 23 so that the shape of the isolated wiring 39a when connected to its end portions forms a dissimilar hexagon in a planar view.

[0136] In this modified example, the planar shapes of the openings 23 are different from one another. This makes it possible to suppress the occurrence of light beams (streaks of light that are observed to trail) that may occur when the wirings 25 are arranged periodically. Although not shown, the wirings 25 may be arranged regularly and the isolated wirings 39a may be arranged irregularly. Furthermore, although not shown, the wirings 25 may be arranged irregularly and the isolated wirings 39a may be arranged regularly.

[0137] Figures 13 and 14 show a third modified example of the wiring board. The modified example shown in Figures 13 and 14 differs in that a dummy wiring layer 30 is provided around the mesh wiring layer 20, but other configurations are substantially the same as the embodiment shown in Figures 1 to 12 described above. In Figures 13 and 14, the same parts as those shown in Figures 1 to 12 are given the same reference numerals and detailed descriptions thereof will be omitted.

[0138] 13, a dummy wiring layer 30 is provided along the periphery of the mesh wiring layer 20. Unlike the mesh wiring layer 20, this dummy wiring layer 30 does not substantially function as an antenna.

[0139] As shown in FIG. 14 , the dummy wiring layer 30 is composed of repeated dummy wirings 30 a each having a predetermined pattern shape. That is, the dummy wiring layer 30 includes a plurality of dummy wirings 30 a, and each dummy wiring 30 a is electrically independent from the mesh wiring layer 20 (the first directional wirings 21 and the second directional wirings 22). The plurality of dummy wirings 30 a are regularly arranged throughout the dummy wiring layer 30. The plurality of dummy wirings 30 a are spaced apart from one another in the planar direction and are arranged to protrude above the substrate 11. That is, each dummy wiring 30 a is electrically independent from the mesh wiring layer 20, the first isolated wirings 35, the second isolated wirings 36, the power supply section 40, and other dummy wirings 30 a. The shape of each dummy wiring 30 a is approximately L-shaped in plan view.

[0140] In this case, the dummy wiring 30a has a shape in which a portion of the pattern shape of the mesh wiring layer 20 described above is missing. This makes it difficult to visually recognize the difference between the mesh wiring layer 20 and the dummy wiring layer 30, and makes the mesh wiring layer 20 arranged on the substrate 11 less visible. As shown in FIG. 14 , the dummy wiring 30a extends parallel to the first directional wiring 21 or the second directional wiring 22. Specifically, the dummy wiring 30a includes a first portion 31a extending parallel to the first directional wiring 21 and a second portion 32a extending parallel to the second directional wiring 22. In this way, the dummy wiring 30a extending parallel to the first directional wiring 21 or the second directional wiring 22 makes the mesh wiring layer 20 arranged on the substrate 11 even less visible. The aperture ratio of the dummy wiring layer 30 may be the same as or different from the aperture ratio of the mesh wiring layer 20, but is preferably close to the aperture ratio of the mesh wiring layer 20.

[0141] As in this modification, the dummy wiring layer 30 that is electrically independent from the mesh wiring layer 20 is provided around the mesh wiring layer 20, thereby making it possible to obscure the outer edge of the mesh wiring layer 20. This makes it possible to make the mesh wiring layer 20 less visible on the surface of the image display device 60, and makes it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye.

[0142] 15 and 16 show a fourth modified example of the wiring substrate. The modified example shown in Figures 15 and 16 differs in that a plurality of dummy wiring layers 30A, 30B having different aperture ratios are provided around the mesh wiring layer 20, but other configurations are substantially the same as those shown in Figures 1 to 14 described above. In Figures 15 and 16, the same parts as those shown in Figures 1 to 14 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0143] 15, a plurality of (two in this case) dummy wiring layers 30A, 30B (a first dummy wiring layer 30A and a second dummy wiring layer 30B) having different aperture ratios are provided along the periphery of the mesh wiring layer 20. Specifically, the first dummy wiring layer 30A is arranged along the periphery of the mesh wiring layer 20, and the second dummy wiring layer 30B is arranged along the periphery of the first dummy wiring layer 30A. Unlike the mesh wiring layer 20, these dummy wiring layers 30A, 30B do not actually function as antennas.

[0144] 16, the first dummy wiring layer 30A is composed of repeated dummy wirings 30a1 each having a predetermined pattern. The second dummy wiring layer 30B is composed of repeated dummy wirings 30a2 each having a predetermined pattern. That is, the dummy wiring layers 30A and 30B each include a plurality of dummy wirings 30a1 and 30a2, and each of the dummy wirings 30a1 and 30a2 is electrically independent from the mesh wiring layer 20. The dummy wirings 30a1 and 30a2 are regularly arranged throughout the entire dummy wiring layers 30A and 30B, respectively. The dummy wirings 30a1 and 30a2 are spaced apart from each other in the planar direction and are arranged to protrude above the substrate 11. Each of the dummy wirings 30a1 and 30a2 is electrically independent from the mesh wiring layer 20, the first isolated wiring 35, the second isolated wiring 36, the power supply section 40, and the other dummy wirings 30a1 and 30a2. Each of the dummy wirings 30a1 and 30a2 has a substantially L-shape in plan view.

[0145] In this case, the dummy wirings 30a1 and 30a2 have a shape in which a portion of the pattern shape of the mesh wiring layer 20 described above is missing. This makes it difficult to visually recognize the difference between the mesh wiring layer 20 and the first dummy wiring layer 30A, and the difference between the first dummy wiring layer 30A and the second dummy wiring layer 30B, and makes it difficult to see the mesh wiring layer 20 arranged on the substrate 11. As shown in Figure 16, the dummy wirings 30a1 and 30a2 extend parallel to the first directional wiring 21 or the second directional wiring 22. Specifically, the dummy wiring 30a1 includes a first portion 31a1 extending parallel to the first directional wiring 21 and a second portion 32a1 extending parallel to the second directional wiring 22. The dummy wiring 30 a 2 includes a first portion 31 a 2 extending parallel to the first directional wiring 21 and a second portion 32 a 2 extending parallel to the second directional wiring 22 .

[0146] The area of ​​each dummy wiring 30a1 in the first dummy wiring layer 30A is larger than the area of ​​each dummy wiring 30a2 in the second dummy wiring layer 30B. In this case, the line width of each dummy wiring 30a1 is the same as the line width of each dummy wiring 30a2, but this is not limited to this, and the line width of each dummy wiring 30a1 may be wider than the line width of each dummy wiring 30a2. Note that other configurations of the dummy wirings 30a1 and 30a2 are similar to the configuration of the dummy wiring 30a in the third modified example, so detailed description will be omitted here.

[0147] In this modification, the aperture ratios of the mesh wiring layer 20 and the multiple dummy wiring layers 30A, 30B preferably increase stepwise from the mesh wiring layer 20 toward the dummy wiring layers 30A, 30B farther from the mesh wiring layer 20. In other words, the aperture ratio of each dummy wiring layer preferably increases gradually from the one closest to the mesh wiring layer 20 to the one farther from it. In this case, the aperture ratio of the first dummy wiring layer 30A is preferably greater than that of the mesh wiring layer 20. The aperture ratio of the second dummy wiring layer 30B is preferably greater than that of the first dummy wiring layer 30A. This makes it possible to further obscure the outer edges of the mesh wiring layer 20 and the dummy wiring layers 30A, 30B. This makes it possible to make the mesh wiring layer 20 even less visible on the surface of the image display device 60.

[0148] In this way, by arranging the dummy wiring layers 30A and 30B electrically independent from the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made more unclear. This makes the mesh wiring layer 20 less visible on the surface of the image display device 60, making it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye. Note that three or more dummy wiring layers having different aperture ratios may be provided around the mesh wiring layer 20.

[0149] Fig. 17 shows a fifth modified example of the wiring board. The modified example shown in Fig. 17 differs in the planar shape of the mesh wiring layer 20, but other configurations are substantially the same as those shown in Figs. 1 to 16. In Fig. 17, the same parts as those shown in Figs. 1 to 16 are given the same reference numerals, and detailed description thereof will be omitted.

[0150] 17 , the first directional wiring 21 and the second directional wiring 22 intersect at an oblique angle (non-right angle), and each opening 23 is formed in a diamond shape in a plan view. The first directional wiring 21 and the second directional wiring 22 are not parallel to either the X direction or the Y direction, respectively, but either one of the first directional wiring 21 and the second directional wiring 22 may be parallel to the X direction or the Y direction. Furthermore, the first isolated wiring 35 and the second isolated wiring 36 intersect at an oblique angle (non-right angle). The first isolated wiring 35 and the second isolated wiring 36 are not parallel to either the X direction or the Y direction, respectively, but either one of the first isolated wiring 35 and the second isolated wiring 36 may be parallel to the X direction or the Y direction.

[0151] It is also possible to combine the multiple components disclosed in the above embodiment and each modification as needed, or to delete some of the components disclosed in the above embodiment and each modification.

Claims

1. A wiring board comprising: a transparent substrate; and a mesh wiring layer disposed on the substrate, the mesh wiring layer including wiring, the mesh wiring layer being surrounded by the wiring to form an opening, and an isolated wiring that is electrically independent from the wiring being provided within the opening.

2. The wiring board according to claim 1, wherein the area ratio of said isolated wiring within said opening is 0.1% or more and 0.3% or less.

3. The wiring board according to claim 1 or 2, wherein the distance between the wiring and the isolated wiring is 4.0 μm or more and 400 μm or less.

4. The wiring board according to any one of claims 1 to 3, wherein the pitch of the isolated wiring is 500 μm or less.

5. The wiring board according to any one of claims 1 to 4, wherein the line width of the isolated wiring is 3.0 μm or less.

6. The wiring board according to any one of claims 1 to 5, wherein the length of the isolated wiring is 50 μm or less.

7. The wiring board according to any one of claims 1 to 6, wherein the isolated wirings are separated from each other via cutouts, and the length of the cutouts is not less than 4.0 µm and not more than 400 µm.

8. The wiring board according to any one of claims 1 to 7, wherein the wiring pitch is not less than 500 µm and not more than 10 mm.

9. The wiring board according to any one of claims 1 to 8, wherein the line width of the wiring is 3.0 μm or less.

10. A wiring board according to any one of claims 1 to 9, wherein the opening ratio of the mesh wiring layer is 98% or more and less than 100%.

11. The wiring board according to any one of claims 1 to 10, wherein at least one of the wirings and the isolated wirings is arranged irregularly.

12. The wiring board according to any one of claims 1 to 11, further comprising a dummy wiring layer provided around the mesh wiring layer and electrically independent from the mesh wiring layer.

13. The wiring board as described in claim 12, wherein a plurality of the dummy wiring layers are provided, and the aperture ratios of the mesh wiring layer and the dummy wiring layer increase stepwise from the mesh wiring layer to the dummy wiring layer furthest from the mesh wiring layer.

14. The wiring board according to any one of claims 1 to 13, having a radio wave transmitting and receiving function.

15. An image display device comprising: a wiring board according to claim 14; and a display device laminated on the wiring board.

16. A method for manufacturing a wiring board, comprising: a step of preparing a transparent substrate; and a step of forming a mesh wiring layer on the substrate, wherein the mesh wiring layer includes wiring, an opening is formed by being surrounded by the wiring, and an isolated wiring that is electrically independent from the wiring is provided within the opening.

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