Wiring substrate and image display device

Abstract

The present application provides a wiring substrate and an image display device. The wiring substrate includes a substrate including a first surface and a second surface located on the opposite side of the first surface; a primer layer disposed on the first surface of the substrate; and a mesh wiring layer disposed on the primer layer. The substrate has transparency. The mesh wiring layer has a first dark color layer disposed on the primer layer, a first metal layer disposed on the first dark color layer, and a second metal layer disposed on the first metal layer. The surface roughness Sa of the first dark color layer is 5 nm or more and 200 nm or less.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on May 16, 2024, entitled "Wiring Substrate and Image Display Device", with application number 202480031783.1 (PCT / JP2024 / 018092). Technical Field

[0002] Embodiments of this disclosure relate to wiring substrates and image display devices. Background Technology

[0003] Currently, portable terminal devices such as smartphones, tablets, and smart glasses (AR, MR, etc.) are undergoing significant advancements in terms of high functionality, miniaturization, thinness, and lightweight design. These portable terminal devices utilize multiple communication frequency bands, thus requiring multiple antennas corresponding to each band. For example, portable terminal devices may incorporate antennas for telephone communication, WiFi (Wireless Fidelity), 3G (Generation), 4G (Generation), 5G (Generation), LTE (Long Term Evolution), Bluetooth (trademark), and NFC (Near Field Communication). However, with the miniaturization of portable terminal devices, the space available for antenna installation is limited, narrowing the design freedom. Furthermore, due to the limited space required to house the antennas, it may not be possible to meet the required radio wave sensitivity.

[0004] Therefore, a thin-film antenna capable of being mounted on the display area of ​​portable terminal devices or the transmission area of ​​smart glasses has been developed. In this thin-film antenna, an antenna pattern is formed on a transparent substrate. The antenna pattern is formed from a mesh-like conductive layer, which consists of conductor portions forming opaque conductive layers and multiple openings forming non-opaque conductive layers.

[0005] Existing technical documents

[0006] Patent documents

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

[0008] However, for example, in conventional thin-film antennas, one or more mesh antennas are mounted on a transparent substrate, but there are areas on the transparent substrate where antenna patterns are formed and areas where no antenna patterns are formed. In this case, because there are areas where no antenna patterns are formed, the areas where antenna patterns are formed are easily visible. Therefore, it is desirable for wiring patterns such as antenna patterns to be difficult to visually identify.

[0009] In addition, for example, in thin-film antennas, in order to prevent the antenna pattern from peeling off from the transparent substrate, it is required to improve the adhesion between the transparent substrate and the antenna pattern.

[0010] This embodiment provides a wiring substrate and an image display device that makes the mesh wiring layer difficult to be visually identified and improves the adhesion between the substrate and the mesh wiring layer.

[0011] In addition, this embodiment provides a wiring substrate and an image display device that make the mesh wiring layer difficult to visually identify. Summary of the Invention

[0012] The embodiments of this disclosure relate to the following [1] to [9]. [1]

[0014] A wiring substrate includes: a substrate having a first surface and a second surface located opposite to the first surface; a base coating disposed on the first surface of the substrate; and a mesh wiring layer disposed on the base coating. The substrate is transparent, and the mesh wiring layer has: a first dark layer disposed on the base coating; a first metal layer disposed on the first dark layer; and a second metal layer disposed on the first metal layer. The surface roughness Sa of the first dark layer is 5 nm or more and 200 nm or less. [2]

[0016] According to the wiring substrate described in [1], the wiring substrate further comprises a second dark layer covering the mesh wiring layer, wherein the surface roughness Sa of the second dark layer is 5 nm or more and 100 nm or less. [3]

[0018] According to the wiring substrate described in [1] or [2], the first metal layer and the second metal layer have different crystallization properties, and the second metal layer has a crystallization property in which the diffraction angle 2θ of the (111) plane is less than 43.4° as measured using CuKα rays as an X-ray source. [4]

[0020] The wiring substrate according to any one of [1] to [3], wherein the dielectric loss tangent of the substrate is less than 0.002. [5]

[0022] According to any one of [1] to [4], the increase in resistance of the mesh wiring layer is less than 20% when the wiring substrate is stretched after being bent 180° around a cylinder with a diameter of 1 mm 100 times. [6]

[0024] The wiring substrate according to any one of [1] to [5], wherein the wiring substrate has millimeter-wave transceiver function and the mesh wiring layer is configured as an array antenna. [7]

[0026] The wiring substrate according to any one of [1] to [6], wherein a dummy wiring layer electrically independent of the grid wiring layer is provided around the grid wiring layer. [8]

[0028] According to the wiring substrate described in [7], a plurality of dummy wiring layers are provided, and the aperture ratio of the mesh wiring layer and the aperture ratio of the dummy wiring layer increase in stages from the mesh wiring layer toward the dummy wiring layer away from the mesh wiring layer. [9]

[0030] An image display device comprising: a wiring substrate as described in any one of [1] to [8]; and a display device stacked on the wiring substrate.

[0031] In addition, the embodiments of this disclosure relate to the following

[10] to

[24] .

[10]

[0033] A wiring substrate includes: a substrate having a first side and a second side located opposite to the first side; and a mesh wiring layer disposed on the first side of the substrate, the substrate being transparent, the mesh wiring layer having wiring, the wiring comprising: a black layer containing resin; a first metal layer disposed on the black layer; and a second metal layer disposed on the first metal layer, the wiring having a linewidth of 5.0 μm or less.

[11]

[0035] According to the wiring substrate of

[10] , the wiring substrate further comprises an undercoating layer disposed between the substrate and the mesh wiring layer.

[12]

[0037] According to the wiring substrate of

[10] or

[11] , the thickness of the black layer is 0.2 μm or more and 1.0 μm or less.

[13]

[0039] The wiring substrate according to any one of

[10] to

[12] , wherein the black layer comprises dye or pigment.

[14]

[0041] The wiring substrate according to any one of

[10] to

[13] , wherein the first metal layer and the second metal layer have different crystallization properties, and the second metal layer has a crystallization property in which the diffraction angle 2θ of the (111) plane is less than 43.4° as measured using CuKα rays as an X-ray source.

[15]

[0043] The wiring substrate according to any one of

[10] to

[14] , wherein the dielectric loss tangent of the substrate is less than 0.002.

[16]

[0045] The wiring substrate according to any one of

[10] to

[15] , wherein, when the wiring substrate is stretched after being bent 180° around a cylinder with a diameter of 1 mm 100 times, the increase in resistance of the mesh wiring layer is less than 20%.

[17]

[0047] The wiring substrate according to any one of

[10] to

[16] , wherein the wiring substrate has millimeter-wave transceiver function and the mesh wiring layer is configured as an array antenna.

[18]

[0049] The wiring substrate according to any one of

[10] to

[17] , wherein a dummy wiring layer electrically independent of the grid wiring layer is provided around the grid wiring layer.

[19]

[0051] According to the wiring substrate described in

[18] , a plurality of dummy wiring layers are provided, and the aperture ratio of the mesh wiring layer and the aperture ratio of the dummy wiring layer increase in stages from the mesh wiring layer toward the dummy wiring layer away from the mesh wiring layer.

[20]

[0053] The wiring substrate according to any one of

[10] to

[19] , wherein the wiring substrate further comprises a dark layer covering the mesh wiring layer. [twenty one]

[0055] According to the wiring substrate described in

[20] , the black layer has a 5° positive reflectance at a wavelength of 700 nm that is lower than that of the dark layer. [twenty two]

[0057] According to the wiring substrate described in

[20] or

[21] , the 5° orthoreflection spectrum of the dark layer and the 5° orthoreflection spectrum of the black layer are different in the visible light wavelength region. [twenty three]

[0059] A wiring substrate includes: a substrate having a first surface and a second surface located opposite to the first surface; a base coating disposed on the first surface of the substrate; and a mesh wiring layer disposed on the base coating, the substrate being transparent, the base coating being a dark-colored layer, the mesh wiring layer having wiring, the wiring comprising: a first metal layer disposed on the base coating; and a second metal layer disposed on the first metal layer. [twenty four]

[0061] An image display device comprising: a wiring substrate as described in any one of

[10] to

[23] ; and a display device stacked on the wiring substrate.

[0062] According to embodiments of this disclosure, the mesh wiring layer can be made difficult to visually identify, and the adhesion between the substrate and the mesh wiring layer can be improved.

[0063] Furthermore, according to embodiments of this disclosure, the mesh wiring layer can be made difficult to visually identify. Attached Figure Description

[0064] Figure 1 This is a top view showing the image display device according to the first embodiment.

[0065] Figure 2 This is a cross-sectional view showing the image display device according to the first embodiment ( Figure 1 (Sectional view along line II-II).

[0066] Figure 3 This is a top view showing the wiring substrate of the first embodiment.

[0067] Figure 4 This is an enlarged top view showing the grid wiring layer of the wiring substrate according to the first embodiment.

[0068] Figure 5 This is a cross-sectional view showing the wiring substrate of the first embodiment. Figure 4 (VV-line sectional view).

[0069] Figure 6 This is a cross-sectional view showing the wiring substrate of the first embodiment. Figure 4 (VI-VI line sectional view).

[0070] Figure 7A This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0071] Figure 7B This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0072] Figure 7C This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0073] Figure 7D This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0074] Figure 7E This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0075] Figure 7F This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0076] Figure 7G This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0077] Figure 7H This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0078] Figure 7I This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0079] Figure 7J This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the first embodiment.

[0080] Figure 8 This is a top view of a wiring substrate showing a first variation of the first embodiment.

[0081] Figure 9 This is an enlarged top view of a wiring substrate showing a first variation of the first embodiment.

[0082] Figure 10 This is a top view of a wiring substrate showing a second variation of the first embodiment.

[0083] Figure 11 This is an enlarged top view of a wiring substrate showing a second variation of the first embodiment.

[0084] Figure 12 This is a top view showing a wiring substrate of a third variation of the first embodiment.

[0085] Figure 13 This is a top view showing the image display device according to the second embodiment.

[0086] Figure 14 This is a cross-sectional view showing the image display device according to the second embodiment ( Figure 13 (Cross-sectional view along line XIV-XIV).

[0087] Figure 15This is a top view showing the wiring substrate of the second embodiment.

[0088] Figure 16 This is an enlarged top view showing the grid wiring layer of the wiring substrate according to the second embodiment.

[0089] Figure 17 This is a cross-sectional view showing the wiring substrate of the second embodiment. Figure 16 (Sectional view along line XVII-XVII).

[0090] Figure 18 This is a cross-sectional view showing the wiring substrate of the second embodiment. Figure 16 (Cross-sectional view along line XVIII-XVIII).

[0091] Figure 19A This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0092] Figure 19B This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0093] Figure 19C This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0094] Figure 19D This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0095] Figure 19E This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0096] Figure 19F This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0097] Figure 19G This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0098] Figure 19H This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0099] Figure 19I This is a cross-sectional view showing a method for manufacturing a wiring substrate according to the second embodiment.

[0100] Figure 20 This is a cross-sectional view of a wiring substrate showing a first variation of the second embodiment.

[0101] Figure 21 This is a cross-sectional view of a wiring substrate showing a first variation of the second embodiment.

[0102] Figure 22This is a cross-sectional view of a wiring substrate showing a second variation of the second embodiment.

[0103] Figure 23 This is a cross-sectional view of a wiring substrate showing a second variation of the second embodiment.

[0104] Figure 24 This is a cross-sectional view of a wiring substrate showing a comparative example.

[0105] Figure 25 This is a graph showing the reflectance spectrum.

[0106] Figure 26 This is a perspective view showing a head-mounted display assembled with a wiring substrate of a second modified embodiment of the second embodiment.

[0107] Figure 27 It is a diagram illustrating the unevenness of the rainbow.

[0108] Figure 28 This is a cross-sectional view of a wiring substrate showing a third variation of the second embodiment.

[0109] Figure 29 This is a cross-sectional view of a wiring substrate showing a third variation of the second embodiment.

[0110] Figure 30 This is a top view of the wiring substrate showing a fourth variation of the second embodiment.

[0111] Figure 31 This is an enlarged top view showing the wiring substrate of the fourth variation of the second embodiment.

[0112] Figure 32 This is a top view showing a fifth variation of the wiring substrate according to the second embodiment.

[0113] Figure 33 This is an enlarged top view showing the wiring substrate of the fifth variation of the second embodiment.

[0114] Figure 34 This is a top view of the wiring substrate showing the sixth variation of the second embodiment. Detailed Implementation

[0115] (First Implementation)

[0116] First, through Figures 1 to 7J One implementation method will be described. Figures 1 to 7J This is a diagram illustrating this embodiment.

[0117] The figures shown below are schematic illustrations. Therefore, for ease of understanding, the size and shape of each part have been appropriately exaggerated. Furthermore, modifications can be made appropriately without departing from the technical concept. In addition, in the figures shown below, the same reference numerals are used for the same parts, and sometimes detailed descriptions are omitted. Furthermore, the dimensions and material names of the components described in this specification are examples of embodiments and are not limiting; appropriate selections can be made. In this specification, terms describing the conditions for determining shape and geometry, such as parallel, orthogonal, and perpendicular, are interpreted in addition to their strict meaning, encompassing substantially the same state.

[0118] In the following embodiments, "X direction" refers to a direction parallel to one side of the image display device. "Y direction" refers to a direction perpendicular to the X direction and parallel to the other side of the image display device. "Z direction" refers to a direction perpendicular to both the X and Y directions and parallel to the thickness direction of the image display device. "Front side" refers to the surface on the positive side in the Z direction, and specifically the surface on the light-emitting side of the image display device. "Back side" refers to the surface on the negative side in the Z direction, and specifically the surface opposite to the surface on the light-emitting side of the image display device. Furthermore, in this embodiment, the mesh wiring layer 20 is described as a mesh wiring layer with radio wave transceiver function (functioning as an antenna), but the mesh wiring layer 20 may also not have radio wave transceiver function.

[0119] Reference Figure 1 and Figure 2 The structure of the image display device of this embodiment will be described.

[0120] like Figure 1 and Figure 2 As shown, the image display device 60 of this embodiment includes a wiring substrate 10 and a display device 61 stacked on the wiring substrate 10. The wiring substrate 10, together with the first transparent adhesive layer 95 and the second transparent adhesive layer 96, constitutes a laminate 70 for the image display device.

[0121] The wiring substrate 10 includes a substrate 11, a base coating 15, a mesh wiring layer 20 having first dark layers 21c and 22c (described later), a second dark layer 18, and a power supply section 40. For example... Figure 2 As shown, the substrate 11 includes a first surface 11a and a second surface 11b located opposite to the first surface 11a. A base coating 15 is disposed on the first surface 11a of the substrate 11. A mesh wiring layer 20 is disposed on the base coating 15. The mesh wiring layer 20 is covered by a second dark layer 18. In addition, a power supply unit 40 is electrically connected to the mesh wiring layer 20. Furthermore, a communication module 63 is disposed on the negative side in the Z direction relative to the display device 61. The image display device laminate 70, the display device 61, and the communication module 63 are housed within a housing 62.

[0122] exist Figure 1 and Figure 2 The image display device 60 shown can transmit and receive radio waves of a specified frequency via the communication module 63, enabling communication. The communication module 63 may include any of the following: a millimeter-wave antenna, a telephone antenna, a WiFi antenna, a 3G antenna, a 4G antenna, a 5G antenna, an LTE antenna, a Bluetooth antenna, an NFC antenna, etc. Examples of such an image display device 60 include portable terminal devices such as smartphones and tablets. Furthermore, the millimeter-wave frequency band is 30 GHz or higher and 100 GHz or lower. Additionally, the frequency band used in 5G is 450 MHz or higher and 6000 MHz or lower in Fr1 (Frequency Range 1), and 24.25 GHz or higher and 52.6 GHz or lower in Fr2 (Frequency Range 2).

[0123] like Figure 2 As shown, the image display device 60 has a light-emitting surface 64. The image display device 60 includes a wiring substrate 10 located on the side of the light-emitting surface 64 (positive side in the Z direction) relative to the display device 61, and a communication module 63 located on the opposite side of the light-emitting surface 64 (negative side in the Z direction) relative to the display device 61.

[0124] The display device 61 is, for example, an organic EL (Electro Luminescence) display device. The display device 61 may include, for example, a metal layer (not shown), a support substrate, a resin substrate, a thin-film transistor (TFT), and an organic EL layer. A touch sensor (not shown) may also be disposed on the display device 61. Furthermore, a wiring substrate 10 is disposed on the display device 61 across a second transparent adhesive layer 96. The display device 61 is not limited to an organic EL display device. For example, the display device 61 may be other display devices with self-illuminating capabilities, or it may be a micro-LED display device including micro-LED elements. Additionally, the display device 61 may be a liquid crystal display device including liquid crystal.

[0125] A cover glass 75 is disposed on the wiring substrate 10, separated by a first transparent adhesive layer 95. It should be noted that a decorative film and a polarizing plate (not shown) may also be disposed between the first transparent adhesive layer 95 and the cover glass 75.

[0126] The first transparent adhesive layer 95 is an adhesive layer that directly or indirectly bonds the wiring substrate 10 to 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 has optical transparency and may also be an OCA (Optical Clear Adhesive) layer. The OCA layer is manufactured, for example, as follows: First, a liquid curable adhesive layer composition containing a polymeric compound is coated onto a release film such as polyethylene terephthalate (PET). Then, it is cured using, for example, ultraviolet light (UV), thereby obtaining an OCA sheet. After the OCA sheet is adhered to an object, the release film is peeled off, thereby obtaining the OCA layer. The material of the first transparent adhesive layer 95 may also be an acrylic resin, a silicone resin, or a polyurethane resin. In particular, the first transparent adhesive layer 95 may also contain an acrylic resin. In this case, the second transparent adhesive layer 96 may also contain an acrylic resin. This effectively 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 B4 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0127] Regarding the first transparent adhesive layer 95, the transmittance of visible light can be 85% or more, or 90% or more. It should be noted that there is no particular upper limit to the transmittance of visible light of the first transparent adhesive layer 95; for example, it can be less than 100%. By setting the transmittance of visible light of the first transparent adhesive layer 95 to the above range, the transparency of the laminate 70 for the image display device can be improved, making it easier to visually identify the display device 61 of the image display device 60. Furthermore, visible light refers to light with a wavelength of 400 nm or more and 700 nm or less. Additionally, a transmittance of 85% or more of visible light means that when measuring the absorbance of the component to be measured (e.g., the first transparent adhesive layer 95), the transmittance is 85% or more across the entire wavelength range of 400 nm or more and 700 nm or less. The absorbance measurement can be performed using a spectrophotometer (spectrometer V-670 manufactured by Nippon Spectrophotometer Co., Ltd.).

[0128] As described above, the wiring substrate 10 is disposed on the light-emitting surface 64 side relative to 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 an area larger 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 the entire surface of the image display device 60 when viewed from above, the overall thickness of the image display device 60 can be reduced.

[0129] As described above, the wiring substrate 10 includes: a transparent substrate 11; a base coating 15 disposed on a first surface 11a of the substrate 11; a mesh wiring layer 20 disposed on the base coating 15; and a second dark layer 18 covering the mesh wiring layer 20. A 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 (not shown). Furthermore, 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 (to the negative side in the Y direction) from between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. Specifically, the area in the wiring substrate 10 where the power supply unit 40 is disposed protrudes outward. This allows for easy electrical connection between the power supply unit 40 and the communication module 63. On the other hand, the area in 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. Further details regarding the wiring substrate 10 will be described later.

[0130] The second transparent adhesive layer 96 is an adhesive layer that directly or indirectly bonds 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. The second transparent adhesive layer 96, like the first transparent adhesive layer 95, has optical transparency and can also be an OCA (Optical Clear Adhesive) layer. The material of the second transparent adhesive layer 96 can also be acrylic resin, silicone resin, or polyurethane resin, etc. In particular, the second transparent adhesive layer 96 can also contain 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 B4 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0131] Regarding the second transparent adhesive layer 96, the transmittance of visible light (light with a wavelength of 400 nm or more and 700 nm or less) can be 85% or more, or 90% or more. It should be noted that there is no particular upper limit to the transmittance of visible light of the second transparent adhesive layer 96; for example, it can be less than 100%. By setting the transmittance of visible light of the second transparent adhesive layer 96 to the above range, the transparency of the laminate 70 for the image display device can be improved, making it easier to visually identify the display device 61 of the image display device 60.

[0132] In such a laminate 70 for an image display device, the difference between the refractive index of the base layer 15 and the refractive index of the first transparent adhesive layer 95 is 0.1 or less, and can be 0.05 or less. Furthermore, the difference between the refractive index of the base layer 15 and the refractive index of the substrate 11 is 0.1 or less, and can be 0.05 or less. Here, refractive index refers to absolute refractive index, which can be determined based on Method A of JIS K-7142. For example, if the material of the first transparent adhesive layer 95 is an acrylic resin (refractive index 1.49), the refractive index of the base layer 15 is set to be 1.39 or more and 1.59 or less. Examples of such materials include fluoropolymers, silicone resins, polyolefin resins, polyester resins, acrylic resins, polycarbonate resins, polyimide resins, and cellulose resins.

[0133] By suppressing the difference between the refractive index of the base coating 15 and the refractive index of the first transparent adhesive layer 95 to less than 0.1, the reflection of visible light at the interface B1 between the base coating 15 and the first transparent adhesive layer 95 can be suppressed, making the substrate 11 with the base coating 15 less visible to the naked eye. Furthermore, by suppressing the difference between the refractive index of the base coating 15 and the refractive index of the substrate 11 to less than 0.1, the reflection of visible light at the interface B2 between the base coating 15 and the substrate 11 can be suppressed, making the substrate 11 less visible to the naked eye.

[0134] Furthermore, in the image display device laminate 70, the difference between the refractive index of the substrate 11 and the refractive index of the first transparent adhesive layer 95 is 0.1 or less, and can be 0.05 or less. Similarly, the difference between the refractive index of the second transparent adhesive layer 96 and the refractive index of the substrate 11 is 0.1 or less, and can also be 0.05 or less. Moreover, the difference between the refractive index of the first transparent adhesive layer 95 and the refractive index of the second transparent adhesive layer 96 can be 0.1 or less, and can also be 0.05 or less. For example, if the materials of the first transparent adhesive layer 95 and the second transparent adhesive layer 96 are acrylic resins (refractive index 1.49), the refractive index of the substrate 11 is set to be 1.39 or more and 1.59 or less. Examples of such materials, as described above, include fluoropolymers, silicone resins, polyolefin resins, polyester resins, acrylic resins, polycarbonate resins, polyimide resins, and cellulose resins.

[0135] By suppressing the difference between the refractive index of the second transparent adhesive layer 96 and the refractive index of the substrate 11 to less than 0.1, the reflection of visible light at the interface B3 between the second transparent adhesive layer 96 and the substrate 11 can be suppressed, making the substrate 11 less visible to the naked eye. Furthermore, by suppressing 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 less than 0.1, the reflection of visible light at the interface B4 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96 can be suppressed, making the first transparent adhesive layer 95 and the second transparent adhesive layer 96 less visible to the naked eye.

[0136] Specifically, the materials of the first transparent adhesive layer 95 and the second transparent adhesive layer 96 can be the same. This further reduces the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, thereby suppressing the reflection of visible light at the interface B4 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0137] exist Figure 2 In this embodiment, the thickness of at least one of the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 can be more than 1.5 times, more than 2 times, or more than 2.5 times the thickness T1 of the substrate 11. Thus, by making the thickness T3 of the first transparent adhesive layer 95 or the thickness T4 of the second transparent adhesive layer 96 sufficiently thick relative to the thickness T1 of the substrate 11, 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. Therefore, it is possible to suppress the generation of a step difference on 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 detect the presence of the substrate 11.

[0138] The thickness of at least one of the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 can be less than 10 times or less than 5 times the thickness T1 of the substrate 11. Therefore, the thickness T3 of the first transparent adhesive layer 95 or the thickness T4 of the second transparent adhesive layer 96 will not become too thick, and the overall thickness of the image display device 60 can be reduced.

[0139] exist Figure 2 In this configuration, the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 can be the same. In this case, the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 can be at least 1.5 times or more than 2.0 times the thickness T1 of the substrate 11. That is, the total thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 (T3+T4) is at least 3 times the thickness T1 of the substrate 11. By making the total thickness T3 and T4 of the first transparent adhesive layer 95 and the second transparent adhesive layer 96 sufficiently thick relative to the thickness T1 of the substrate 11, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 deform (shrink) in the thickness direction in the region overlapping with the substrate 11. As a result, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 absorb the thickness of the substrate 11. Therefore, at the periphery of the substrate 11, the generation of step difference on the first transparent adhesive layer 95 or the second transparent adhesive layer 96 can be suppressed, making it difficult for an observer to detect the presence of the substrate 11.

[0140] When the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 are the same, the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 can be less than 5 times or less than 3 times the thickness T1 of the substrate 11. Therefore, the thicknesses T3 and T4 of both the first transparent adhesive layer 95 and the second transparent adhesive layer 96 will not become excessively thick, allowing for a thinner overall thickness of the image display device 60.

[0141] Specifically, the thickness T1 of the substrate 11 can be, for example, 2 μm or more, 10 μm or more, or 15 μm or more. By setting the thickness T1 of the substrate 11 to 2 μm or more, the strength of the wiring substrate 10 can be maintained, making it difficult for the first direction wiring 21 and the second direction wiring 22 of the mesh wiring layer 20 (described later) to deform. Alternatively, the thickness T1 of the substrate 11 can be, for example, 200 μm or less, 50 μm or less, or 25 μm or less. By setting the thickness T1 of the substrate 11 to 200 μm or less, the generation of step differences on the first transparent adhesive layer 95 and the second transparent adhesive layer 96 at the periphery of the substrate 11 can be suppressed, making it difficult for an observer to detect the presence of the substrate 11. Furthermore, by setting the thickness T1 of the substrate 11 to 50 μm or less, the generation of step differences on 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 even more difficult for an observer to detect the presence of the substrate 11.

[0142] The thickness T3 of the first transparent adhesive layer 95 can be, for example, 15 μm or more, or 20 μm or more. The thickness T3 of the first transparent adhesive layer 95 can be, for example, less than 500 μm, less than 300 μm, or less than 250 μm. The thickness T4 of the second transparent adhesive layer 96 can be, for example, 15 μm or more, or 20 μm or more. The thickness T4 of the second transparent adhesive layer 96 can be, for example, less than 500 μm, less than 300 μm, or less than 250 μm.

[0143] Refer again Figure 2 A cover glass 75 is disposed on a first transparent adhesive layer 95. This cover glass 75 is a glass component that allows light to pass through. Alternatively, the cover glass 75 may be plate-shaped, and its shape may be rectangular when viewed from above. The thickness of the cover glass 75 may be, for example, 200 μm or more and 1000 μm or less, or 300 μm or more and 700 μm or less. The length of the cover glass 75 in the long side direction (Y direction) may be, for example, 20 mm or more and 500 mm or less, or 100 mm or more and 200 mm or less. The length of the cover glass 75 in the short side direction (X direction) may be 20 mm or more and 500 mm or less, or 50 mm or more and 100 mm or less.

[0144] like Figure 1As shown, the image display device 60 is generally rectangular in shape when viewed from above, with its long side parallel to the Y-direction and its short side parallel to the X-direction. The length L4 of the image display device 60 in the long side (Y-direction) can be, for example, 20mm or more and 500mm or less, or 100mm or more and 200mm or less. The length L5 of the image display device 60 in the short side (X-direction) can be, for example, 20mm or more and 500mm or less, or 50mm or more and 100mm or less. Furthermore, the planar shape of the image display device 60 can also be a rectangle with rounded corners.

[0145] Next, refer to Figures 3 to 6 The structure of the wiring substrate will be explained. Figures 3 to 6 This is a diagram showing the wiring substrate of this embodiment.

[0146] Figure 3 The wiring substrate 10 shown is used in the image display device 60 described above (see reference). Figure 1 and Figure 2 The wiring substrate 10 can be disposed at a position closer to the light-emitting surface 64 than the display device 61, and disposed between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. As described above, such a wiring substrate 10 includes: a transparent substrate 11; a base coating layer 15 disposed on the substrate 11; a mesh wiring layer 20 disposed on the base coating layer 15; and a second dark layer 18 covering the mesh wiring layer 20. In addition, a power supply unit 40 is electrically connected to the mesh wiring layer 20.

[0147] The substrate 11 is approximately rectangular in shape when viewed from above. In the illustrated example, its long side is parallel to the X-direction, and its short side is parallel to the Y-direction. The substrate 11 is transparent and approximately flat, with a generally uniform thickness. The length L1 of the substrate 11 in the first direction (Y-direction) can be selected, for example, within a range of 3 mm to 300 mm. The length L2 of the substrate 11 in the second direction (X-direction) (see reference...) Figure 1 For example, it can be selected within the range of 3mm to 300mm. In addition, the planar shape of the substrate 11 can also be a rectangle with rounded corners.

[0148] Regarding the material of the substrate 11, any material that is transparent and electrically insulating in the visible light region is acceptable. For example, organic insulating materials such as polyester resins, acrylic resins, polycarbonate resins, polyimide resins, polyolefin resins, cellulose resins, or fluoropolymers can be used as the material of the substrate 11. Polyester resins can also be polyethylene terephthalate, etc. Acrylic resins can also be polymethyl methacrylate, etc. Polyolefin resins can be cyclic olefin polymers, etc. Cellulose resins can be triacetyl cellulose, etc. Fluoropolymers can also be PTFE or PFA, etc. For example, organic insulating materials such as cyclic olefin polymers (e.g., ZF-16 manufactured by ZEON Corporation of Japan) or polynorbornene polymers (manufactured by Sumitomo Bakelite Corporation) can also be used as the material of the substrate 11. Furthermore, glass or ceramics can be appropriately selected as the material of the substrate 11 depending on the application. Although an example of a single layer constituting the substrate 11 is illustrated, it is not limited to this, and a structure with multiple substrates or layers stacked can also be used. In addition, the substrate 11 can be a film-like component or a plate-like component.

[0149] The dielectric loss tangent of substrate 11 can be 0.002 or less, or 0.001 or less. Furthermore, the lower limit of the dielectric loss tangent of substrate 11 is not particularly limited and can be set to be greater than 0. By setting the dielectric loss tangent of substrate 11 to the above range, especially 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 electromagnetic waves can be reduced.

[0150] The relative permittivity of substrate 11 is not particularly limited and can be 2 or higher and 10 or lower. By making the relative permittivity of substrate 11 2 or higher, the selection of materials for substrate 11 can be increased. Furthermore, by making the relative permittivity of substrate 11 10 or lower, the gain loss associated with the transmission and reception of electromagnetic waves can be reduced. That is, when the relative permittivity of substrate 11 increases, the impact of substrate 11 thickness on electromagnetic wave transmission becomes greater. Additionally, if there is an adverse effect on electromagnetic wave transmission, the dielectric loss tangent of substrate 11 increases, and the gain loss associated with the transmission and reception of electromagnetic waves may increase. Conversely, by making the relative permittivity of substrate 11 10 or lower, the impact of substrate 11 thickness on electromagnetic wave transmission can be reduced. Therefore, the gain loss associated with the transmission and reception of electromagnetic waves can be reduced. This is particularly beneficial when the electromagnetic waves (e.g., millimeter waves) transmitted and received by the mesh wiring layer 20 are high-frequency.

[0151] The dielectric loss tangent and relative permittivity of substrate 11 can be measured according to IEC 62562. Specifically, firstly, a test piece is prepared by cutting out the portion of substrate 11 before the formation of the mesh wiring layer 20. The dimensions of the test piece are: a width of 10 mm or more and 20 mm or less, and a length of 50 mm or more and 100 mm or less. Next, the dielectric loss tangent or relative permittivity is measured according to IEC 62562.

[0152] In this embodiment, the substrate 11 is transparent. In this specification, "transparent" means that the transmittance of visible light (light with a wavelength of 400 nm or more and 700 nm or less) is 85% or more. The transmittance of visible light of the substrate 11 can be 85% or more, or it can be 90% or more. Furthermore, there is no particular limitation on the upper limit of the transmittance of visible light of the substrate 11; for example, it can be 100% or less. By setting the transmittance of visible light of the substrate 11 to the above range, the transparency of the wiring substrate 10 can be improved, making it easier to visually identify the display device 61 of the image display device 60.

[0153] Next, the base coating 15 will be described. The base coating 15 serves to improve the adhesion between the mesh wiring layer 20 and the substrate 11. In this embodiment, the base coating 15 is provided over approximately the entire area of ​​the first surface 11a of the substrate 11. Therefore, it is not necessary to pattern the base coating 15. As a result, the number of process steps can be reduced. Alternatively, the base coating 15 may be provided only in the area of ​​the first surface 11a of the substrate 11 where the mesh wiring layer 20 is provided.

[0154] The base coating 15 comprises a polymer material. This effectively improves the adhesion between the mesh wiring layer 20 and the substrate 11. In this case, a colorless and transparent polymer material can be used as the material for the base coating 15.

[0155] The base coating 15 may contain an acrylic resin or a polyester resin. This improves the adhesion between the mesh wiring layer 20 and the substrate 11 more effectively. When the base coating 15 contains an acrylic resin, polymers with acrylic acid, methacrylic acid, and their derivatives as monomers can be listed as examples. Examples of acrylic resins include polymers copolymerized with acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methacrylic acid, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl acrylate, acrylamide, acrylonitrile, hydroxyl acrylate, etc., as main components, and copolymerized with monomers capable of copolymerizing them (e.g., styrene, divinylbenzene, acrylonitrile, etc.). In addition to the monomers mentioned above, dimers having two acryloyl or methacryloyl groups per molecule, or polyfunctional urethane acrylates, can be added to the resin as the main component. Organic molecules having two or more epoxy groups per molecule can also be added to the resin as the main component. Therefore, by crosslinking the acrylic resin, the resin can be cured to form the primer layer 15. The cured primer layer exhibits excellent adhesion. In addition, it can also exhibit excellent water resistance, acid resistance, alkali resistance, or solvent resistance, or a combination thereof. Therefore, it is possible to prevent the adhesion between the mesh wiring layer 20 and the substrate 11 from decreasing during wiring formation or decreasing over time.

[0156] Furthermore, when the base coating 15 comprises a polyester resin, the base coating 15 can be formed, for example, by crosslinking the hydroxyl-containing polyester resin using a curing agent that reacts with hydroxyl groups, thereby curing it. Examples of hydroxyl-containing polyester resins include polyester polyols, and examples of curing agents include polyisocyanates and / or polyisocyanate prepolymers. The base coating 15 formed by curing the polyester polyol with polyisocyanates and / or polyisocyanate prepolymers exhibits excellent adhesion. Furthermore, it can also exhibit excellent water resistance, acid resistance, alkali resistance, or solvent resistance, or combinations thereof. Therefore, it is possible to suppress the decrease in adhesion between the mesh wiring layer 20 and the substrate 11 over time. In addition, the base coating 15 formed by curing the polyester polyol with polyisocyanates and / or polyisocyanate prepolymers exhibits excellent heat resistance. Therefore, it is less susceptible to the effects of heat generated in various film-forming processes performed after the base coating 15 is formed, and the generation of whitening or cracking of the base coating 15 caused by heat can be suppressed.

[0157] Furthermore, examples of polyisocyanates and / or polyisocyanate prepolymers include IPDI-based, XDI-based, and HDI-based polyisocyanates and / or polyisocyanate prepolymers. Using these, yellowing of the base coating 15 can be suppressed. Here, IPDI-based refers to isophorone diisocyanate and its modified forms, XDI-based refers to xylene diisocyanate and its modified forms, and HDI-based refers to hexamethylolamine diisocyanate and its modified forms. Examples of modified forms include trimethylolpropane (TMP) adducts, isocyanurates, biuret, and urethane.

[0158] Furthermore, the polymer material of the base coating 15 can also be cross-linked and cured by irradiating it with visible light, ultraviolet light, X-rays, electron beams, alpha rays, beta rays, gamma rays, etc. This improves the damage resistance and heat resistance of the base coating 15.

[0159] Furthermore, the transmittance of visible light (light with a wavelength of 400 nm or more and 700 nm or less) of the base coating 15 can be 85% or more, or 90% or more. It should be noted that there is no particular upper limit to the transmittance of visible light of the base coating 15; for example, it can be less than 100%. By setting the transmittance of visible light of the base coating 15 to the above range, the transparency of the wiring substrate 10 can be improved, making it easier to visually identify the display device 61 of the image display device 60.

[0160] The thickness T2 of the base coating 15 (length in the Z direction, refer to...) Figure 5 The thickness T2 of the base coating 15 can be 0.05 μm or more and 0.5 μm or less. By making the thickness T2 of the base coating 15 0.05 μm or more, the adhesion between the mesh wiring layer 20 and the substrate 11 can be effectively improved. In addition, by making the thickness T2 of the base coating 15 0.5 μm or less, the transparency of the wiring substrate 10 can be ensured.

[0161] In this embodiment, the mesh wiring layer 20 is configured as an electromagnetic wave transceiver. In this case, the mesh wiring layer 20 is configured with an antenna pattern that functions as an antenna. The mesh wiring layer 20 can also be configured as an array antenna. Thus, by configuring the mesh wiring layer 20 as an array antenna, the performance of millimeter-wave antennas for transmitting and receiving millimeter-wave waves with high linearity can be improved. Furthermore, an array antenna refers to an antenna in which multiple antenna elements (radiating elements) are regularly arranged, and the amplitude and phase of the excitation of the elements can be independently controlled.

[0162] like Figure 3 As shown, multiple mesh wiring layers 20 are formed on the substrate 11. More than four mesh wiring layers 20 can also be provided. In the illustrated example, four mesh wiring layers 20 are formed on the substrate 11 (see reference). Figure 1 Additionally, such as Figure 3 As shown, the mesh wiring layer 20 may not exist on the entire surface of the substrate 11, but only in a portion of the substrate 11. Each mesh wiring layer 20 may also have the same shape as each other. In this case, the length (Y-direction distance) L of the end-side portion 20b of each mesh wiring layer 20 (described later) is... a Error and width (distance in the X direction) W a The error can also be within 10%. Therefore, the performance of millimeter-wave antennas can be effectively improved.

[0163] The mesh cabling layer 20 has a base-side portion (transmission section) 20a on the power supply section 40 side and an end-side portion (transmitter / receiver section) 20b connected to the base-side portion 20a. The base-side portion 20a is connected to the power supply section 40. In this case, the base-side portion (transmission section) 20a can also be configured as a microstrip line or a coplanar line. The shapes of the base-side portion 20a and the end-side portion 20b are both approximately rectangular when viewed from above. In this case, the width (X-direction distance) of the end-side portion 20b is larger than the width (X-direction distance) of the base-side portion 20a.

[0164] The end portion 20b of the mesh wiring layer 20 corresponds to a specified frequency band. That is, the length (distance in the Y direction) L of the end portion 20b... a This becomes the length corresponding to a specific frequency band. Furthermore, the lower the frequency band, the longer the 20-bit length L of the end portion. a The longer the mesh wiring layer 20, the better. Besides corresponding to millimeter-wave antennas, it can also correspond to any of the following: telephone antennas, WiFi antennas, 3G antennas, 4G antennas, 5G antennas, LTE antennas, Bluetooth antennas, NFC antennas, etc. Furthermore, the multiple end portions 20b can have different lengths and correspond to different frequency bands. Alternatively, if the wiring substrate 10 does not have radio wave transceiver functionality, each mesh wiring layer 20 can also function as a hover function, fingerprint authentication, heater, noise cutoff (shielding), etc. Furthermore, the hover function refers to the ability to operate the display even without direct user contact.

[0165] In the illustrated example, the long side of the end portion 20b is parallel to the X direction, and its short side is parallel to the Y direction. Alternatively, the end portion 20b may also have its long side parallel to the Y direction and its short side parallel to the X direction. The length L of the end portion 20b in the Y direction is... a For example, it can be selected within a range of 1mm to 100mm. The width W of the end-side portion 20b in the X direction... aFor example, it can be selected within a range of 1mm to 100mm. In particular, in the case where the mesh wiring layer 20 is a millimeter-wave antenna, the length L of the end portion 20b... a It can be 1mm or more, or 1.5mm or more. In the case where the mesh wiring layer 20 is a millimeter-wave antenna, the length L of the end portion 20b... a It can be less than 10mm or less than 5mm.

[0166] The distance between the mesh wiring layers 20 can be appropriately set according to the corresponding frequency, but it can also be more than 1 mm and less than 30 mm. That is, the distance D between the end portions 20b 20b (refer to Figure 3 The distance can be between 1mm and 30mm. By setting an appropriate distance, the desired antenna directivity and gain can be improved.

[0167] like Figure 4 As shown, the mesh wiring layer 20 has a pattern shape in which the metal wires are arranged in a grid or mesh pattern. This pattern shape is repeated in the X and Y directions. That is, the mesh wiring layer 20 has a pattern shape composed of a portion extending in a first direction (e.g., the Y direction) (first direction wiring 21 described later) and a portion extending in a second direction (e.g., the X direction) (second direction wiring 22 described later).

[0168] like Figure 4 As shown, the mesh wiring layer 20 has multiple wirings. Specifically, the mesh wiring layer 20 has multiple first-direction wirings 21 and multiple second-direction wirings 22 connecting the multiple first-direction wirings 21. The multiple first-direction wirings 21 and the multiple second-direction wirings 22 are integrated as a whole, thereby forming a grid-like or mesh-like shape. Each first-direction wiring 21 extends linearly in the length direction (Y direction) of the mesh wiring layer 20. Each second-direction wiring 22 extends linearly in the width direction (X direction) of the mesh wiring layer 20. In addition, the first-direction wirings 21 and the second-direction wirings 22 may also extend in directions that are not parallel to either the X or Y direction.

[0169] In the mesh wiring layer 20, multiple openings 23 are formed by being surrounded by adjacent first-direction wiring 21 and adjacent second-direction wiring 22. The transparent substrate 11 is exposed from each opening 23. As a result, the overall transparency of the wiring substrate 10 can be improved.

[0170] Each opening 23 has a roughly square planar shape when viewed from above. That is, the first-direction wiring 21 and the second-direction wiring 22 are arranged at equal intervals. The spacing P1 between the multiple first-direction wirings 21 can be set to a range of 0.01 mm or more and 1 mm or less. Similarly, the spacing P2 between the multiple second-direction wirings 22 can be set to a range of 0.01 mm or more and 1 mm or less. By arranging the multiple first-direction wirings 21 and the multiple second-direction wirings 22 at equal intervals, the size of the openings 23 within the mesh wiring layer 20 is consistent, making the mesh wiring layer 20 difficult to discern with the naked eye. Furthermore, the spacing P1 of the first-direction wirings 21 is equal to the spacing P2 of the second-direction wirings 22. Therefore, each opening 23 is roughly square when viewed from above, and the transparent base coating 15 and substrate 11 are exposed from each opening 23. Therefore, by increasing the area of ​​each opening 23, the overall transparency of the wiring substrate 10 can be improved. Furthermore, the length L3 of one side of each opening 23 can be set to a range of 0.01 mm or more and 1 mm or less. Additionally, each first-direction wiring 21 and each second-direction wiring 22 are orthogonal to each other, but are not limited to this; they can also intersect each other at acute or obtuse angles. Furthermore, the shape of the opening 23 can be the same shape and size across the entire surface, or it can be changed depending on the location, thus resulting in unevenness across the entire surface.

[0171] like Figure 5 As shown, each first-direction wiring 21 has a cross-section (X-direction cross-section) perpendicular to its long side direction, which is approximately rectangular or approximately square. In this case, the cross-sectional shape of the first-direction wiring 21 is approximately uniform along the long side direction (Y-direction) of the first-direction wiring 21. Figure 6 As shown, the cross-section (i.e., the Y-direction cross-section) of each second-direction wiring 22 perpendicular to its long side direction is approximately rectangular or approximately square, and has a shape approximately the same as the cross-section (X-direction cross-section) shape of the first-direction wiring 21 described above. In this case, the cross-sectional shape of the second-direction wiring 22 is approximately uniform along the long side direction (X-direction) of the second-direction wiring 22. The cross-sectional shapes of the first-direction wiring 21 and the second-direction wiring 22 do not necessarily have to be approximately rectangular or approximately square. For example, the cross-sectional shapes of the first-direction wiring 21 and the second-direction wiring 22 may also be approximately trapezoidal with the front side (positive Z-direction side) narrower than the back side (negative Z-direction side), or shapes with curved sides on both sides in the width direction.

[0172] In this embodiment, the line width W1 of the first direction wiring 21 (refer to...) Figure 5 ) and the line width W2 of the second direction wiring 22 (refer to Figure 6There are no particular limitations, and the appropriate width can be selected according to the application. Here, the linewidth W1 of the first direction wiring 21 is the width of the cross section perpendicular to its long side (length in the X direction), and the linewidth W2 of the second direction wiring 22 is the width of the cross section perpendicular to its long side (length in the Y direction). For example, the linewidth W1 of the first direction wiring 21 can be selected in the range of 0.1μm or more and 5.0μm or less, or it can be 0.2μm or more and 2.0μm or less. Similarly, the linewidth W2 of the second direction wiring 22 can be selected in the range of 0.1μm or more and 5.0μm or less, or it can be 0.2μm or more and 2.0μm or less. By making the linewidth W1 of the first direction wiring 21 and the linewidth W2 of the second direction wiring 22 both 5.0μm or less, the mesh wiring layer 20 can be made difficult to be visually discernible to the naked eye.

[0173] The height H1 of the first direction wiring 21 (see...) Figure 5 ) and the height H2 of the second direction wiring 22 (see Figure 6 There are no particular restrictions, and the appropriate height can be selected depending on the application. Here, the height H1 of the first direction wiring 21 and the height H2 of the second direction wiring 22 are the lengths in the Z direction, respectively. The height H1 of the first direction wiring 21 and the height H2 of the second direction wiring 22 can be selected, for example, within a range of 60 nm or more and 5.0 μm or less.

[0174] Here, as Figure 5 and Figure 6 As shown, the mesh wiring layer 20 includes: first dark layers 21c and 22c disposed on the base coating layer 15; first metal layers 21a and 22a disposed on the first dark layers 21c and 22c; and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. Specifically, the first directional wiring 21 includes a first dark layer 21c disposed on the base coating layer 15, a first metal layer 21a disposed on the first dark layer 21c, and a second metal layer 21b disposed on the first metal layer 21a. Furthermore, the second directional wiring 22 includes a first dark layer 22c disposed on the base coating layer 15, a first metal layer 22a disposed on the first dark layer 22c, and a second metal layer 22b disposed on the first metal layer 22a.

[0175] The first dark layers 21c and 22c are layers used to make the mesh wiring layer 20 difficult to be visually identified by the naked eye by suppressing the reflection of visible light incident on the mesh wiring layer 20 from the substrate 11 side.

[0176] The first dark layers 21c and 22c can also be dark layers, such as black. The first dark layers 21c and 22c can also be formed by performing a darkening treatment (blackening treatment) on a metal layer formed by sputtering or vapor deposition. In this case, the first dark layers 21c and 22c can also be formed as layers composed of metal oxides or metal sulfides. Alternatively, the first dark layers 21c and 22c can also be formed as layers containing palladium or tellurium. Furthermore, the first dark layers 21c and 22c can also be formed as dark metal layers on the surface of the base layer 15 by sputtering or vapor deposition. In this case, the first dark layers 21c and 22c can also be layers composed of copper, nickel, or chromium (hereinafter also referred to as copper, etc.). Alternatively, the first dark layers 21c and 22c can also be layers composed of alloys such as copper, nitrides or oxides of elemental metals such as copper, or nitrides or oxides of alloys such as copper.

[0177] The surface roughness Sa (arithmetic mean height of the surface) of the first dark layers 21c and 22c is 5 nm or more and 200 nm or less. By making the surface roughness Sa of the first dark layers 21c and 22c 5 nm or more, the reflection of visible light on the first dark layers 21c and 22c can be suppressed. Therefore, the mesh wiring layer 20 can be made less visible to the naked eye. By making the surface roughness Sa of the first dark layers 21c and 22c 200 nm or less, the haze value of the first dark layers 21c and 22c can be suppressed from becoming too high. As a result, the presence of the first dark layers 21c and 22c is difficult for the observer to detect. Therefore, the mesh wiring layer 20 can be made less visible to the naked eye. In measuring the surface roughness Sa of the first dark layers 21c and 22c, a laser microscope (KEYENCE Corporation, VK-X 1000) was used, based on ISO 25178, to measure the surface roughness Sa of the back side of the first dark layers 21c and 22c. When measuring the surface roughness Sa of the first dark layers 21c and 22c, firstly, the wiring substrate 10 was placed in the laser microscope such that a laser was irradiated onto the wiring substrate 10 from the second surface 11b side of the substrate 11. The objective lens magnification was set to 50x. The measurement area in this case was approximately 270μm × 200μm. Next, the wiring substrate 10 was irradiated onto the wiring substrate 10 from the second surface 11b side of the substrate 11. Thus, the surface roughness Sa of the first dark layers 21c and 22c was measured. According to this measurement method, even after the first metal layers 21a, 22a and the second metal layers 21b, 22b are stacked on the first dark layers 21c, 22c, the surface roughness Sa of the first dark layers 21c, 22c can still be measured.

[0178] The thickness d of the first dark layer 21c and 22c 1c d 2cThe thickness can be greater than 0.1 μm and less than 5.0 μm, greater than 0.2 μm and less than 4.5 μm, or greater than 0.3 μm and less than 4.0 μm. This is achieved by adjusting the thickness d of the first dark layers 21c and 22c. 1c d 2c A thickness of 0.1 μm or more can improve the adhesion between the base coating 15 and the first dark layers 21c and 22c, as well as the adhesion between the first dark layers 21c and 22c and the first metal layers 21a and 22a. Furthermore, by increasing the thickness d of the first dark layers 21c and 22c... 1c d 2c By setting the thickness d to below 5.0 μm, the haze values ​​of the first dark layers 21c and 22c can be suppressed from becoming excessively high, making it difficult for observers to detect their presence. Therefore, the mesh wiring layer 20 can be made less visually discernible to the naked eye. Furthermore, by setting the thickness d of the first dark layers 21c and 22c... 1c d 2c With a thickness of less than 5.0 μm, the formation time of the mesh wiring layer 20 can be shortened.

[0179] The first metal layers 21a and 22a improve the adhesion between the substrate 11 and the mesh wiring layer 20. Additionally, the first metal layers 21a and 22a serve as seed layers when the second metal layers 21b and 22b are formed by electroplating. The first metal layers 21a and 22a can also be formed by sputtering or vapor deposition. Furthermore, the first metal layers 21a and 22a can also be formed using the same method as the first dark layers 21c and 22c.

[0180] The thickness d of the first metal layers 21a and 22a 1a d 2a The thickness can be above 10nm and below 1000nm, above 30nm and below 500nm, or above 50nm and below 300nm. This is achieved by adjusting the thickness d of the first metal layers 21a and 22a. 1a d 2a With a thickness of 10 nm or more, the second metal layers 21b and 22b can be effectively supported when formed on the first metal layers 21a and 22a. Furthermore, by increasing the thickness d of the first metal layers 21a and 22a... 1a d 2a With a wavelength below 1000nm, the formation time of the mesh wiring layer 20 can be shortened.

[0181] The second metal layers 21b and 22b increase the height H1 of the first-direction wiring 21 and the height H2 of the second-direction wiring 22. This reduces the resistance of the first-direction wiring 21 and the second-direction wiring 22. The second metal layers 21b and 22b can be formed by plating or electroplating.

[0182] The thickness d of the second metal layers 21b and 22b 1b d 2b The thickness can be above 50nm and below 4990nm, above 100nm and below 2000nm, or above 200nm and below 1800nm. This is achieved by adjusting the thickness d of the second metal layers 21b and 22b. 1b d 2b With a thickness of 50nm or more, it is possible to increase the height H1 of the first-direction wiring 21 and the height H2 of the second-direction wiring 22, and to reduce the resistance values ​​of the first-direction wiring 21 and the second-direction wiring 22. This is achieved by increasing the thickness d of the second metal layers 21b and 22b. 1b d 2b With a wavelength below 4990nm, the formation time of the mesh wiring layer 20 can be shortened.

[0183] The first dark layers 21c and 22c and the first metal layers 21a and 22a may also have the same crystallization characteristics. On the other hand, the first metal layers 21a and 22a and the second metal layers 21b and 22b may also have different crystallization characteristics. At least one of the following can be different: crystallization ratio, crystal structure, crystallite size, and crystal plane spacing. For example, the diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a, measured using CuKα rays as an X-ray source, may be greater than the diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b. For example, the first metal layers 21a and 22a may also have crystallization characteristics where the diffraction angle 2θ of the (111) plane, measured using CuKα rays as an X-ray source, is less than 43.430°. This improves the adhesion between the first dark layers 21c and 22c and the first metal layers 21a and 22a. In this case, the diffraction angle 2θ can be 43.42° or less, or 43.41° or less. Furthermore, the lower limit of the diffraction angle 2θ is not particularly limited; it can be 43.25° or more, 43.30° or more, or 43.35° or more. It should be noted that the diffraction angle can be measured using an X-ray diffraction apparatus (Rigaku Corporation, Smart Lab, 9kW type). The diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b are measured at the power supply unit 40. As described below, the power supply unit 40 is formed simultaneously with the first metal layers 21a, 22a and the second metal layers 21b, 22b by a portion of the second metal film 51 constituting the first metal layers 21a, 22a and a portion of the third metal film 52 constituting the second metal layers 21b, 22b. Therefore, at the power supply unit 40, the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b, 22b can be measured. In this case, compared with the case of measuring the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a in a grid wiring layer 20 with relatively narrow line widths W1, W2, the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a can be measured more accurately. The measurement conditions are shown below.

[0184] Measurement mode: 2θ / θ measurement (Out-Plane)

[0185] X-ray source: Cu-Kα 45kV-50mA

[0186] Optical system: lumped method

[0187] Incident-side optical system 1: Soler slit 5deg

[0188] Incident-side optical system 2: Variable slit (IS) 1deg

[0189] Length limit slit: 10mm

[0190] Light-receiving side optical system 1: Variable slits (RS1) 1deg, (RS2) 0.3mm

[0191] Light-receiving side optical system 2: PSA OPEN / Soler slit 5deg

[0192] Detector: Blink Counter

[0193] Measurement range: 35deg-80deg

[0194] Step: 0.02deg

[0195] Measurement time: 2.0 deg / min

[0196] The second metal layers 21b and 22b can have a crystal characteristic where the diffraction angle 2θ of the (111) plane, measured using CuKα rays as an X-ray source, is less than 43.4°. Therefore, the formability of the second metal layers 21b and 22b can be improved when they are formed by etching. The diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b can be less than 43.390°, less than 43.380°, or less than 43.370°.

[0197] Regarding the materials for the first directional wiring 21 and the second directional wiring 22, any conductive metallic material is acceptable. That is, the materials for the first dark layers 21c and 22c, the first metal layers 21a and 22a, and the second metal layers 21b and 22b can all be conductive metallic materials. In this embodiment, the materials for the first directional wiring 21 and the second directional wiring 22 are copper, but this is not a limitation. For example, the materials for the first directional wiring 21 and the second directional wiring 22 can be metallic materials such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or alloys containing these metals. Furthermore, the materials for the first metal layers 21a and 22a and the second metal layers 21b and 22b can be the same. This improves the adhesion between the first metal layers 21a and 22a and the second metal layers 21b and 22b.

[0198] The overall aperture ratio At of the mesh wiring layer 20 can 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 to 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 can also be 95% or more and less than 100%. Thus, the conductivity of the wiring substrate 10 can be ensured while improving the transparency of the wiring substrate 10. Furthermore, the aperture ratio refers to the percentage (%) of the area of ​​the open region to the unit area of ​​a specified area (e.g., the entire area of ​​the mesh wiring layer 20). The open region refers to the area where the substrate 11 is exposed due to the absence of metal portions such as the first direction wiring 21 and the second direction wiring 22.

[0199] However, when performing a flexural strength test on the wiring substrate 10, the increase in resistance of the mesh wiring layer 20 can be less than 20% or less than 10%. The flexural strength test refers to a test in which the wiring substrate 10 is bent 180° around a cylinder with a diameter of 1 mm and then stretched 100 times using a cylindrical mandrel bending tester.

[0200] Specifically, the experiment is conducted as follows: First, the resistance between the two ends of the long side of the mesh wiring layer 20 is measured. This resistance value is set as R0 (Ω). Next, the wiring substrate 10 is wound around the cylinder of a cylindrical mandrel bending tester, with the two ends of the long side of the wiring substrate 10 facing opposite directions at 180°. Then, the wiring substrate 10 is removed from the cylinder and extended flat. This operation is repeated 100 times. Afterward, the resistance between the two ends of the long side of the mesh wiring layer 20 is measured again. This resistance value is set as R1 (Ω). The value obtained by calculating ((R1-R0) / R0)×100 (%) is taken as the increase in resistance value. By keeping this increase in resistance value below 20%, the durability of the wiring substrate 10 can be improved when it is used in a bent or flexed manner.

[0201] Next, we will explain the second dark layer 18. For example... Figure 5 and Figure 6 As shown, a second dark layer (blackening layer) 18 is formed on the mesh wiring layer 20 of the wiring substrate 10. This second dark layer 18 is used to make the mesh wiring layer 20 difficult to see with the naked eye by suppressing the reflection of visible light caused by the mesh wiring layer 20. The second dark layer 18 covers the entire area of ​​the mesh wiring layer 20. This second dark layer 18 can also cover the entire area of ​​the power supply section 40.

[0202] The second dark layer 18 can also be a dark layer, such as black. Alternatively, the second dark layer 18 can also be a layer with a roughened surface.

[0203] The surface roughness Sa of the second dark layer 18 is 5 nm or more and 100 nm or less. By making the surface roughness Sa of the second dark layer 18 5 nm or more, the reflection of visible light on the surface of the second dark layer 18 can be suppressed. Therefore, the mesh wiring layer 20 covered by the second dark layer 18 is not easily visible to the naked eye of an observer. By making the surface roughness Sa of the second dark layer 18 100 nm or less, the haze value of the second dark layer 18 can be suppressed from becoming too high. As a result, it is difficult for an observer to detect the presence of the second dark layer 18. Therefore, the mesh wiring layer 20 covered by the second dark layer 18 is not easily visible to the naked eye of an observer. In this case, the surface roughness Sa is determined using a laser microscope (KEYENCE Corporation, VK-X 1000) based on ISO 25178.

[0204] The second dark layer 18 can be formed, for example, by performing a darkening treatment (blackening treatment) on a portion of the metal material constituting the mesh wiring layer 20 or the power supply section 40, thereby forming the second dark layer 18 as a part of the mesh wiring layer 20 or the power supply section 40. In this case, the second dark layer 18 can also be formed as a layer composed of metal oxides or metal sulfides. Alternatively, the second dark layer 18 can also be formed on the surface of the mesh wiring layer 20 or the power supply section 40 as a coating of dark material or a plating layer of nickel or chromium. Furthermore, the second dark layer 18 can also be formed by roughening the surface of the mesh wiring layer 20 or the power supply section 40.

[0205] Alternatively, although not shown, a protective layer can be formed on the base coating 15 to cover the mesh wiring layer 20 and the second dark layer 18. The protective layer protects the mesh wiring layer 20 and is formed to cover at least the mesh wiring layer 20 in the substrate 11. Materials used for the protective layer can be colorless and transparent insulating resins such as copolymers of acrylic resins and their modified resins, such as poly(methyl methacrylate) and poly(ethyl methacrylate), polyester, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, and polyvinyl butyral, polyurethane, epoxy resin, polyamide, and chlorinated polyolefin.

[0206] Refer again Figure 3 A power supply section 40 is electrically connected to the mesh wiring layer 20. This power supply section 40 is composed of a generally rectangular conductive thin plate-like component. The long side of the power supply section 40 is parallel to the X-direction, and the short side is parallel to the Y-direction. Furthermore, the power supply section 40 is disposed at the end of the long side of the substrate 11 (the negative end in the Y-direction). The material of the power supply section 40 can be, for example, metals such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or alloys containing these metals. This power supply section 40 is assembled on the wiring substrate 10 onto the image display device 60 (see reference 10). Figure 1 and Figure 2 The power supply unit 40 is electrically connected to the communication module 63 of the image display device 60 via a power supply line (not shown). Furthermore, the power supply unit 40 is disposed on the first surface 11a of the substrate 11, but is not limited thereto; a portion or all of the power supply unit 40 may be located outside the periphery of the substrate 11. Alternatively, the power supply unit 40 may be flexibly formed to wrap around the side or back of the image display device 60. In this case, the power supply unit 40 may also be electrically connected to the communication module 63 on the side or back of the image display device 60.

[0207] Next, refer to Figures 7A to 7J The manufacturing method of the wiring substrate 10 of this embodiment will be described.

[0208] First, such as Figure 7A As shown, a substrate 11 is prepared, comprising a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The substrate 11 is transparent.

[0209] Next, as Figure 7B As shown, a base coating 15 is formed on the substrate 11. At this time, the base coating 15 can also be formed over approximately the entire area of ​​the first surface 11a of the substrate 11. Methods for forming the base coating 15 include roller coating, gravure coating, gravure reverse coating, microgravure coating, slot die coating, mold coating, doctor blade coating, inkjet coating, dispenser coating, mating coating, spraying, screen printing, offset printing, and flexographic printing.

[0210] Next, a mesh wiring layer 20 is formed on the base layer 15, wherein the mesh wiring layer 20 includes a plurality of first-direction wirings 21 and a plurality of second-direction wirings 22 connecting the plurality of first-direction wirings 21.

[0211] At this point, firstly, as Figure 7C As shown, a first metal film 55 is laminated over approximately the entire surface area of ​​the base coating 15. This first metal film 55 is used to form the first dark layers 21c and 22c. For example, copper, copper alloys, nitrides or oxides of elemental metals such as copper, or nitrides or oxides of alloys such as copper can be used, and it can be formed by sputtering or vapor deposition. The thickness of the first metal film 55 can be 10 nm or more and 1000 nm or less. In this embodiment, the first metal film 55 may also contain copper.

[0212] like Figure 7DAs shown, a second metal film 51 is laminated over approximately the entire surface area of ​​the first metal film 55. This second metal film 51 is used to form the first metal layers 21a and 22a. The second metal film 51 can also be formed, for example, by sputtering. The thickness of the second metal film 51 can be 10 nm or more and 1000 nm or less. In this embodiment, the second metal film 51 may also contain copper.

[0213] Next, as Figure 7E As shown, a third metal film 52 is stacked on the second metal film 51. This third metal film 52 is used to form the second metal layers 21b and 22b. Alternatively, the second metal film 51 can be used as a seed layer and formed using electroplating. The thickness of the third metal film 52 can be 50 nm or more and 4990 nm or less. In this embodiment, the third metal film 52 may also contain copper. Furthermore, the above-described process of stacking the first metal film 55 ( Figure 7C The process of laminating the second metal film 51 () Figure 7D This can also be performed in a vacuum chamber (not shown). On the other hand, the process of laminating the third metal film 52 ( Figure 7E It can also be performed outside a vacuum chamber (not shown).

[0214] Next, as Figure 7F As shown, a photocurable insulating resist 53 is supplied to approximately the entire surface area of ​​the third metal film 52. Examples of such photocurable insulating resist 53 include organic resins such as acrylic resins and epoxy resins.

[0215] Next, as Figure 7G As shown, the insulating layer 54 is formed by photolithography. In this case, the insulating layer 54 (resist pattern) is formed by patterning a photocurable insulating resist 53 using photolithography. At this time, the insulating layer 54 is formed such that a third metal film 52 corresponding to the first direction wiring 21 and the second direction wiring 22 is exposed.

[0216] Next, as Figure 7H As shown, the third metal film 52, the second metal film 51, and the first metal film 55 on the first surface 11a of the substrate 11, located in the portion not covered by the insulating layer 54, are removed. At this time, a wet treatment using strong acids such as ferric chloride, copper chloride, sulfuric acid / hydrochloric acid, persulfate, hydrogen peroxide, or aqueous solutions thereof, or combinations thereof, is performed to etch the third metal film 52, the second metal film 51, and the first metal film 55 so that the first surface 11a of the substrate 11 is exposed. In this wet treatment, the liquid used for the third metal film 52 and the second metal film 51 can be different from the liquid used for the first metal film 55.

[0217] Next, as Figure 7IAs shown, the insulating layer 54 is removed. In this case, the insulating layer 54 on the third metal film 52 is removed by performing a wet treatment using a permanganate solution or N-methyl-2-pyrrolidone, an acid or alkali solution, or a dry treatment using oxygen plasma.

[0218] Next, as Figure 7J As shown, a second dark layer 18 is formed. In this case, the second dark layer 18 can also be formed by performing a darkening treatment (blackening treatment) on a portion of the first metal film 55, the second metal film 51, and the third metal film 52. Alternatively, the second dark layer 18 can also be formed on the surface of the first metal film 55, the second metal film 51, and the third metal film 52 as a coating of dark material or a plating layer of nickel or chromium. Moreover, the second dark layer 18 can also be formed by roughening the surfaces of the first metal film 55, the second metal film 51, and the third metal film 52.

[0219] In this way, a wiring substrate 10 can be obtained, comprising a substrate 11, a base coating 15 disposed on a first surface 11a of the substrate 11, a mesh wiring layer 20 disposed on the base coating 15, and a second dark layer 18 covering the mesh wiring layer 20. In this case, the mesh wiring layer 20 includes first-direction wiring 21 and second-direction wiring 22. At this time, the power supply section 40 may also be formed from a portion of the first metal film 55, the second metal film 51, and the third metal film 52.

[0220] Then, across Figure 2 The first transparent adhesive layer 95 and the second transparent adhesive layer 96 shown are stacked on the wiring substrate 10 to form a display device 61, thereby obtaining an image display device 60 having the wiring substrate 10 and the display device 61 stacked on the wiring substrate 10.

[0221] Next, the function of this embodiment, which is constructed in this way, will be explained.

[0222] like Figure 1 and Figure 2 As shown, the wiring substrate 10 is assembled onto the image display device 60, which has a display device 61. At this time, the wiring substrate 10 is disposed on the display device 61. The grid 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. Thus, radio waves of a predetermined frequency can be transmitted and received via the grid wiring layer 20, thereby enabling communication using the image display device 60.

[0223] According to this embodiment, the mesh wiring layer 20 includes: first dark layers 21c and 22c disposed on the base coating layer 15; first metal layers 21a and 22a disposed on the first dark layers 21c and 22c; and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. By forming the first metal layers 21a and 22a on the first dark layers 21c and 22c, and forming the second metal layers 21b and 22b on the first metal layers 21a and 22a, the adhesion between the first dark layers 21c and 22c and the first metal layers 21a and 22a, as well as the adhesion between the first metal layers and the second metal layers, can be improved. Therefore, the adhesion between the substrate 11 and the mesh wiring layer 20 can be improved. Furthermore, the following embodiments illustrate that by having the mesh wiring layer 20 have first dark layers 21c, 22c, first metal layers 21a, 22a, and second metal layers 21b, 22b, the adhesion between the substrate 11 and the mesh wiring layer 20 can be improved.

[0224] Furthermore, according to this embodiment, the surface roughness Sa of the first dark layers 21c and 22c is 5 nm or more and 200 nm or less. This suppresses the reflection of visible light on the back surface of the first dark layers 21c and 22c. Additionally, it prevents the haze value of the first dark layers 21c and 22c from becoming excessively high, making it difficult for an observer to detect their presence. Therefore, when an observer visually identifies the wiring substrate 10 from the substrate 11 side, the mesh wiring layer 20 is less likely to be visually detected by the naked eye.

[0225] Furthermore, according to this embodiment, the mesh wiring layer 20 has first metal layers 21a, 22a disposed on the first dark layers 21c, 22c, and second metal layers 21b, 22b disposed on the first metal layers 21a, 22a. This effectively increases the height H1 of the first direction wiring 21 and the height H2 of the second direction wiring 22. Consequently, the resistance values ​​of the first direction wiring 21 and the second direction wiring 22 can be reduced.

[0226] Furthermore, according to this embodiment, the surface roughness Sa of the second dark layer 18 is 5 nm or more and 100 nm or less. This suppresses the reflection of visible light on the surface of the second dark layer 18. Additionally, it prevents the haze value of the second dark layer 18 from becoming excessively high, making it difficult for an observer to detect its presence. Therefore, the mesh wiring layer 20 covered by the second dark layer 18 is less likely to be visually discernible to the naked eye.

[0227] Furthermore, according to this embodiment, the wiring substrate 10 includes a substrate 11, a base coating 15 disposed on the substrate 11, a mesh wiring layer 20 disposed on the base coating 15, and a second dark layer 18 covering the mesh wiring layer 20. Additionally, the substrate 11 is transparent. Furthermore, the mesh wiring layer 20 has a mesh-like pattern formed by conductor portions that are formed as opaque conductive layers and a plurality of openings 23. Therefore, the transparency of the wiring substrate 10 is ensured. Thus, when the wiring substrate 10 is disposed on the display device 61, the display device 61 can be visually identified through the openings 23 of the mesh wiring layer 20 without obstructing the visual visibility of the display device 61.

[0228] Next, a modified example of the wiring substrate of the first embodiment will be described.

[0229] Figure 8 and Figure 9 A first variation of the wiring substrate of the first embodiment is shown. Figure 8 and Figure 9 The difference in the variant shown is that a dummy wiring layer 30 is provided around the mesh wiring layer 20, while the other structures are the same as described above. Figures 1 to 7J The shapes shown are roughly the same. Figure 8 and Figure 9 In the middle, to and Figures 1 to 7J Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0230] exist Figure 8 In the wiring substrate 10 shown, a dummy wiring layer 30 is provided around the grid wiring layer 20. The dummy wiring layer 30 can be covered by the second dark layer 18. This dummy wiring layer 30 is different from the grid wiring layer 20 and does not actually function as an antenna.

[0231] like Figure 9 As shown, the dummy wiring layer 30 is composed of repeating dummy wirings 30a having a defined unit pattern shape. That is, the dummy wiring layer 30 includes multiple dummy wirings 30a of the same shape, each dummy wiring 30a being electrically independent of the grid wiring layer 20 (first direction wiring 21 and second direction wiring 22). Furthermore, the multiple dummy wirings 30a are regularly arranged throughout the entire area of ​​the dummy wiring layer 30. The multiple dummy wirings 30a are separated from each other in the planar direction and are protruding from the substrate 11. That is, each dummy wiring 30a is electrically independent of the grid wiring layer 20, the power supply section 40, and other dummy wirings 30a. The shape of each dummy wiring 30a is approximately L-shaped when viewed from above.

[0232] In this case, the dummy wiring 30a has a unit pattern shape that makes the aforementioned mesh wiring layer 20 (see reference) Figure 4The shape is formed by the absence of a portion of the ) . As a result, the difference between the mesh wiring layer 20 and the dummy wiring layer 30 is difficult to identify visually, and the mesh wiring layer 20 disposed on the substrate 11 is difficult to see.

[0233] like Figure 9 As shown, the dummy wiring 30a extends parallel to either the first-direction wiring 21 or the second-direction wiring 22. Specifically, the dummy wiring 30a includes a first portion 31a extending parallel to the first-direction wiring 21 and a second portion 32a extending parallel to the second-direction wiring 22. The first portion 31a has a shape in which a portion of the first-direction wiring 21 is missing. Furthermore, the second portion 32a has a shape in which a portion of the second-direction wiring 22 is missing. Since the other structures of the first portion 31a and the second portion 32a are the same as those of the first-direction wiring 21 and the second-direction wiring 22, detailed descriptions are omitted here. Thus, because the dummy wiring 30a extends parallel to either the first-direction wiring 21 or the second-direction wiring 22, the mesh wiring layer 20 disposed on the substrate 11 becomes more difficult to see. The aperture ratio of the dummy wiring layer 30 may be the same as or different from that of the mesh wiring layer 20. Even when the aperture ratio of the dummy routing layer 30 is different from that of the mesh routing layer 20, the aperture ratio of the dummy routing layer 30 can still be close to that of the mesh routing layer 20.

[0234] In this way, by setting a dummy wiring layer 30 that is electrically independent of the mesh wiring layer 20 around the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made unclear. As a result, the mesh wiring layer 20 is difficult to see on the surface of the image display device 60, making it difficult for the user of the image display device 60 to identify the mesh wiring layer 20 with the naked eye.

[0235] Figure 10 and Figure 11 A second variation of the wiring substrate of the first embodiment is shown. Figure 10 and Figure 11 The difference in the variant shown is that two or more dummy wiring layers 30A and 30B with different aperture ratios are provided around the mesh wiring layer 20, while the other structures are the same as described above. Figures 1 to 9 The shapes shown are roughly the same. Figure 10 and Figure 11 In the middle, to and Figures 1 to 9 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0236] exist Figure 10In the wiring substrate 10 shown, multiple (in this case, two) dummy wiring layers 30A and 30B (first dummy wiring layer 30A and second dummy wiring layer 30B) with different aperture ratios are arranged around the grid wiring layer 20. Specifically, the first dummy wiring layer 30A is arranged around the grid wiring layer 20, and the second dummy wiring layer 30B is arranged around the first dummy wiring layer 30A. The dummy wiring layers 30A and 30B can be covered by the second dark layer 18. Unlike the grid wiring layer 20, the dummy wiring layers 30A and 30B do not actually function as antennas.

[0237] like Figure 11 As shown, the first dummy wiring layer 30A is formed by repeating dummy wirings 30a1 with a defined unit pattern shape. Similarly, the second dummy wiring layer 30B is formed by repeating dummy wirings 30a2 with a defined unit pattern shape. That is, dummy wiring layers 30A and 30B each contain multiple dummy wirings 30a1 and 30a2 of the same shape, and each dummy wiring 30a1 and 30a2 is electrically independent of the grid wiring layer 20. Furthermore, the dummy wirings 30a1 and 30a2 are regularly arranged throughout the entire area of ​​the dummy wiring layers 30A and 30B, respectively. Each dummy wiring 30a1 and 30a2 is separated from each other in the planar direction and protrudes from the substrate 11. Each dummy wiring 30a1 and 30a2 is electrically independent of the grid wiring layer 20, the power supply section 40, and other dummy wirings 30a1 and 30a2. The shapes of each dummy wiring 30a1 and 30a2 are approximately L-shaped when viewed from above.

[0238] In this case, the dummy wiring 30a1 and 30a2 have a unit pattern shape that makes the aforementioned mesh wiring layer 20 (see reference) Figure 4 The shape is formed by the absence of a portion of the dummy wiring layer 20. Therefore, the differences between the mesh wiring layer 20 and the first dummy wiring layer 30A, and between the first dummy wiring layer 30A and the second dummy wiring layer 30B, are difficult to discern visually, making the mesh wiring layer 20 disposed on the substrate 11 difficult to see. For example... Figure 11 As shown, dummy wirings 30a1 and 30a2 extend parallel to either the first direction wiring 21 or the second direction wiring 22. Specifically, dummy wiring 30a1 includes a first portion 31a1 extending parallel to the first direction wiring 21 and a second portion 32a1 extending parallel to the second direction wiring 22. Dummy wiring 30a2 includes a first portion 31a2 extending parallel to the first direction wiring 21 and a second portion 32a2 extending parallel to the second direction wiring 22.

[0239] Furthermore, 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 linewidth of each dummy wiring 30a1 is the same as the linewidth of each dummy wiring 30a2, but this is not a limitation; the linewidth of each dummy wiring 30a1 may also be larger than the linewidth of each dummy wiring 30a2. Moreover, the other structures of the dummy wirings 30a1 and 30a2 are the same as those of the dummy wiring 30a in the first modified example, therefore detailed descriptions are omitted here.

[0240] In this modified example, the aperture ratio of the mesh wiring layer 20 and the two or more dummy wiring layers 30A and 30B can also increase in stages from the mesh wiring layer 20 toward the dummy wiring layers 30A and 30B away from the mesh wiring layer 20. In other words, the aperture ratio of each dummy wiring layer can also gradually increase from a position close to the mesh wiring layer 20 toward a position away from the mesh wiring layer 20. In this case, the aperture ratio of the first dummy wiring layer 30A can also be larger than the aperture ratio of the mesh wiring layer 20. The aperture ratio of the second dummy wiring layer 30B can be larger than the aperture ratio of the first dummy wiring layer 30A. As a result, the outer edges of the mesh wiring layer 20 and the dummy wiring layers 30A and 30B can be made less clear. Therefore, it is more difficult to see the mesh wiring layer 20 on the surface of the image display device 60.

[0241] In this way, by configuring dummy wiring layers 30A and 30B that are electrically independent of the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made less distinct. This makes the mesh wiring layer 20 difficult to see on the surface of the image display device 60, making it difficult for the user of the image display device 60 to visually identify the mesh wiring layer 20. Furthermore, three or more dummy wiring layers with different aperture ratios can be provided around the mesh wiring layer 20.

[0242] Figure 12 A third variation of the wiring substrate according to the first embodiment is shown. Figure 12 In the variant shown, the planar shape of the mesh wiring layer 20 is different, but the other structures are the same as described above. Figures 1 to 11 The shapes shown are roughly the same. Figure 12 In the middle, to and Figures 1 to 11 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0243] Figure 12 This is an enlarged top view showing the mesh wiring layer 20 of the third modified example. Figure 12In the diagram, the first directional wiring 21 and the second directional wiring 22 intersect at an angle (not at a right angle), and the shape of each opening 23 is rhomboid when viewed from above. Although the first directional wiring 21 and the second directional wiring 22 are not parallel to the X and Y directions respectively, either the first directional wiring 21 or the second directional wiring 22 can be parallel to either the X or Y direction.

[0244] [Example]

[0245] Next, specific embodiments of this implementation will be described.

[0246] (Example 1)

[0247] Making with Figure 3 The wiring substrate shown is a 100 μm thick polyethylene terephthalate substrate. Additionally, a 0.1 μm thick polyester resin is used as the base coating.

[0248] In addition, first-direction wiring and second-direction wiring are formed on the base layer. In this case, as a first metal film (first dark layer), a copper nitride vapor-deposited film with a thickness of 0.1 μm is formed on the polyester resin serving as the base layer by vapor deposition. Furthermore, as a second metal film (first metal layer), a copper vapor-deposited film with a thickness of 0.1 μm is formed on the first metal film by vapor deposition. Then, as a third metal film (second metal layer), a copper plating layer with a thickness of 1.0 μm is formed on the second metal film by plating. Afterwards, a photocurable insulating resist is formed on the third metal film, and a photoresist pattern covering the first-direction wiring and the second-direction wiring pattern is formed by exposure and development. Then, etching is performed using a ferric chloride aqueous solution, followed by resist removal using an alkaline aqueous solution. The linewidth of the first-direction wiring and the second-direction wiring is set to 2.0 μm, and the spacing is set to 100 μm. Furthermore, the first dark layer and the first metal layer are formed inside a vacuum chamber, and the second metal layer is formed outside the vacuum chamber. At this point, the surface roughness Sa of the first dark layer is 17 nm.

[0249] (1) Visual recognition assessment test

[0250] Next, the visual recognizability of the mesh wiring layer in the wiring substrate was confirmed. At this point, the mesh wiring layer was observed from the substrate side (negative side in the Z direction).

[0251] (2) Adhesion evaluation test

[0252] Next, the adhesion of the mesh wiring layer to the substrate was evaluated. First, adhesive tape (manufactured by NICHIBAN Co., Ltd., Cellotte (registered trademark)) was applied to the mesh wiring layer. Then, the adhesive tape was peeled off from the wiring substrate to check whether the mesh wiring layer was adhered to the adhesive tape.

[0253] (Comparative Example 1)

[0254] Instead of forming a first metal layer, a second metal layer is formed directly on the first dark layer. The thickness of the second metal layer is 1.1 μm. Otherwise, the visual recognition evaluation test and the adhesion evaluation test were performed in the same manner as in Example 1.

[0255] The results are shown in Table 1. In the visual recognition evaluation test column of Table 1, "A (excellent)" means that the mesh wiring layer cannot be visually identified with the naked eye. Additionally, in the adhesion evaluation test column of Table 1, "A (excellent)" means that no mesh wiring layer is attached to the adhesive tape. "B (poor)" means that a mesh wiring layer is attached to the adhesive tape.

[0256] [Table 1]

[0257] As a result, as shown in Table 1, the mesh wiring layer cannot be visually identified in the wiring substrate of Example 1 and the wiring substrate of Comparative Example 1. Therefore, it can be seen that in this embodiment, the mesh wiring layer is difficult to visually identify.

[0258] Furthermore, as shown in Table 1, in the wiring substrate of Comparative Example 1, a mesh wiring layer is attached to the adhesive tape. Specifically, in the wiring substrate of Comparative Example 1, the second metal layer is peeled off from the first dark layer, thereby attaching the second metal layer to the adhesive tape. In contrast, in the wiring substrate of Example 1, the mesh wiring layer is not attached to the adhesive tape. That is, it can be seen that by forming the first metal layer on the first dark layer that has undergone darkening treatment using the same method (e.g., vapor deposition) as the first dark layer, the adhesion between the first dark layer and the first metal layer can be improved. It can also be seen that by forming a second metal layer containing the same metal as the first metal layer on the first metal layer that has not undergone darkening treatment, the adhesion between the first metal layer and the second metal layer can be improved. Therefore, it can be seen that in this embodiment, the adhesion between the substrate and the mesh wiring layer can be improved.

[0259] (Second Implementation)

[0260] Next, through Figures 13 to 19I The second embodiment will be described. Figures 13 to 19I This is a diagram illustrating the second embodiment. Figures 13 to 19IIn China, sometimes with Figures 1 to 12 The same parts as those in the first embodiment shown are labeled with the same reference numerals and detailed descriptions are omitted.

[0261] Reference Figure 13 and Figure 14 The structure of the image display device of this embodiment will be described.

[0262] like Figure 13 and Figure 14 As shown, the image display device 60 of this embodiment includes a wiring substrate 10 and a display device 61 stacked on the wiring substrate 10. The wiring substrate 10, together with the first transparent adhesive layer 95 and the second transparent adhesive layer 96, constitutes a laminate 70 for the image display device.

[0263] The wiring substrate 10 includes: a transparent substrate 11; and a mesh wiring layer 20 disposed on a first surface 11a of the substrate 11 (described later). Additionally, the wiring substrate 10 may also include: a base coating layer 15 disposed between the substrate 11 and the mesh wiring layer 20; and a power supply section 40. (Example...) Figure 14 As shown, the substrate 11 includes a first surface 11a and a second surface 11b located opposite to the first surface 11a. A base coating 15 is disposed on the first surface 11a of the substrate 11. A mesh wiring layer 20 is disposed on the base coating 15. Furthermore, a power supply unit 40 is electrically connected to the mesh wiring layer 20. A communication module 63 is disposed on the negative side in the Z direction relative to the display device 61. The image display device laminate 70, the display device 61, and the communication module 63 are housed within a housing 62.

[0264] Next, the image display device laminate 70 will be described in detail. As described above, the image display device laminate 70 is composed of a wiring substrate 10, a first transparent adhesive layer 95, and a second transparent adhesive layer 96. A cover glass 75 is disposed on the wiring substrate 10, separated by the first transparent adhesive layer 95. It should be noted that a decorative film (not shown) and a polarizing plate may also be disposed between the first transparent adhesive layer 95 and the cover glass 75. Furthermore, the image display device laminate 70 can also be mounted on a frame 91 (see reference 1). Figure 26 And assembled into head-mounted displays (smart glasses).

[0265] Next, refer to Figures 15 to 18 The structure of the wiring substrate will be explained. Figures 15 to 18 This is a diagram showing the wiring substrate of this embodiment.

[0266] Figure 15 and Figure 16 The wiring substrate 10 shown is used in the image display device 60 described above (see reference). Figure 13 and Figure 14The wiring substrate 10 can be disposed closer to the light-emitting surface 64 than the display device 61, between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. As described above, such a wiring substrate 10 includes: a transparent substrate 11; a base coating layer 15 disposed on the substrate 11; and a mesh wiring layer 20 disposed on the base coating layer 15. In addition, a power supply unit 40 is electrically connected to the mesh wiring layer 20.

[0267] Here, as Figure 17 and Figure 18 As shown, the mesh wiring layer 20 includes black layers 21d and 22d disposed on the base coating layer 15, first metal layers 21a and 22a disposed on the black layers 21d and 22d, and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. Specifically, the first directional wiring 21 includes a black layer 21d disposed on the base coating layer 15, a first metal layer 21a disposed on the black layer 21d, and a second metal layer 21b disposed on the first metal layer 21a. Furthermore, the second directional wiring 22 includes a black layer 22d disposed on the base coating layer 15, a first metal layer 22a disposed on the black layer 22d, and a second metal layer 22b disposed on the first metal layer 22a.

[0268] Among them, the black layers 21d and 22d are used to make the mesh wiring layer 20 difficult to be identified by the naked eye by suppressing the reflection of visible light incident on the mesh wiring layer 20 from the substrate 11 side.

[0269] The black layers 21d and 22d can be, for example, dark-colored layers such as black. The materials constituting the black layers 21d and 22d are not particularly limited, as long as they can provide the desired light-blocking properties. In this embodiment, the black layers 21d and 22d contain resin. Thus, when the black layers 21d and 22d contain resin, the line widths W1 and W2 can be easily narrowed such that the line width W1 of the first direction wiring 21 and the line width W2 of the second direction wiring 22 are both 5.0 μm or less. In this case, the black layers 21d and 22d can also be cured products containing a black pigment in an adhesive resin. As the adhesive resin for the black layers 21d and 22d, materials capable of dispersing the black pigment are preferred. Examples of adhesive resins include photosensitive resins containing reactive vinyl groups such as acrylate-based, methacrylate-based, polyvinyl cinnamate-based, or cyclized rubber-based resins. The black layers 21d and 22d can also contain dyes or pigments as the black pigment. Specifically, the black layers 21d and 22d can contain pigments such as carbon black and titanium black.

[0270] The surface roughness Sa (arithmetic mean height of the surface) of black layers 21d and 22d can be 5 nm or more and 200 nm or less. By making the surface roughness Sa of black layers 21d and 22d 5 nm or more, the reflection of visible light on black layers 21d and 22d can be suppressed. Therefore, the mesh wiring layer 20 can be made less visible to the naked eye. By making the surface roughness Sa of black layers 21d and 22d 200 nm or less, the haze value of black layers 21d and 22d can be suppressed from becoming too high. Thus, the presence of black layers 21d and 22d can be difficult for the observer to detect. Therefore, the mesh wiring layer 20 can be made less visible to the naked eye. When measuring the surface roughness Sa of black layers 21d and 22d, a laser microscope (KEYENCE Corporation, VK-X 1000) was used, and the surface roughness Sa of the back surface of black layers 21d and 22d was measured according to ISO 25178. When measuring the surface roughness Sa of black layers 21d and 22d, firstly, the wiring substrate 10 is placed in a laser microscope such that a laser is irradiated onto the wiring substrate 10 from the second surface 11b side of the substrate 11. The magnification of the objective lens is set to 50x. The measurement area at this time is approximately 270μm × 200μm. Next, the wiring substrate 10 is irradiated onto the wiring substrate 10 from the second surface 11b side of the substrate 11. In this way, the surface roughness Sa of black layers 21d and 22d is measured. According to this measurement method, even after the first metal layers 21a and 22a and the second metal layers 21b and 22b are stacked on the black layers 21d and 22d, the surface roughness Sa of the black layers 21d and 22d can still be measured.

[0271] The thickness d of the black layers 21d and 22d 1d d 2d The thickness can be greater than 0.2 μm and less than 1.0 μm, greater than 0.3 μm and less than 0.8 μm, or greater than 0.4 μm and less than 0.6 μm. This is achieved by adjusting the thickness d of the black layer at 21d and 22d. 1d d 2d A thickness of 0.2 μm or more can improve the adhesion between the base coating 15 and the black layers 21d and 22d, as well as the adhesion between the black layers 21d and 22d and the first metal layers 21a and 22a. Furthermore, by increasing the thickness d of the black layers 21d and 22d... 1d d 2d With a thickness below 1.0 μm, the haze values ​​of the black layers 21d and 22d can be suppressed from becoming too high, making it difficult for observers to detect the presence of the black layers 21d and 22d. Therefore, the mesh wiring layer 20 is not easily visible to the naked eye.

[0272] In this embodiment, the first metal layers 21a and 22a and the second metal layers 21b and 22b may also have different crystallization characteristics. Specifically, the first metal layers 21a and 22a and the second metal layers 21b and 22b may differ from each other in at least one of the following: crystallization ratio, crystal structure, crystallite size, and crystal plane spacing. For example, the diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a, measured using CuKα rays as an X-ray source, is greater than the diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b. For example, the first metal layers 21a and 22a may also have a crystallization characteristic where the diffraction angle 2θ of the (111) plane, measured using CuKα rays as an X-ray source, is 43.430° or less. This improves the adhesion between the black layers 21d and 22d and the first metal layers 21a and 22a. In this case, the diffraction angle 2θ can be 43.42° or less, or 43.41° or less. Furthermore, the lower limit of the diffraction angle 2θ is not particularly limited; it can be 43.25° or more, 43.30° or more, or 43.35° or more. It should be noted that the diffraction angle can be measured using an X-ray diffraction apparatus (Rigaku Corporation, SmartLab, 9kW type). The diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b are measured at the power supply unit 40. As described later, the power supply unit 40 is formed simultaneously with the first metal layers 21a and 22a and the second metal layers 21b and 22b by a portion of the first metal film 501 constituting the first metal layers 21a and 22a and a portion of the second metal film 502 constituting the second metal layers 21b and 22b. Therefore, at the power supply section 40, the diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b and 22b can be measured. In this case, compared with the case of measuring the diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a in a grid wiring layer 20 with relatively narrow line widths W1 and W2, the diffraction angle 2θ of the (111) plane of the first metal layers 21a and 22a can be measured more accurately. The measurement conditions are shown below.

[0273] Measurement mode: 2θ / θ measurement (Out-Plane)

[0274] X-ray source: Cu-Kα 45kV-50mA

[0275] Optical system: lumped method

[0276] Incident-side optical system 1: Soler slit 5deg

[0277] Incident-side optical system 2: Variable slit (IS) 1deg

[0278] Length limit slit: 10mm

[0279] Light-receiving side optical system 1: Variable slits (RS1) 1deg, (RS2) 0.3mm

[0280] Light-receiving side optical system 2: PSA OPEN / Soler slit 5deg

[0281] Detector: Blink Counter

[0282] Measurement range: 35-80 degrees

[0283] Step: 0.02deg

[0284] Measurement time: 2.0 deg / min

[0285] Regarding the materials of the first metal layers 21a, 22a and the second metal layers 21b, 22b in the first direction wiring 21 and the second direction wiring 22, any conductive metal material is acceptable. In this embodiment, the materials of the first metal layers 21a, 22a and the second metal layers 21b, 22b are copper, but this is not a limitation. For example, the materials of the first metal layers 21a, 22a and the second metal layers 21b, 22b can be metals such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or alloys containing these metals. Furthermore, the materials of the first metal layers 21a, 22a and the second metal layers 21b, 22b can also be the same material. This improves the adhesion between the first metal layers 21a, 22a and the second metal layers 21b, 22b.

[0286] Next, refer to Figures 19A to 19I The manufacturing method of the wiring substrate 10 of this embodiment will be described.

[0287] First, such as Figure 19A As shown, a substrate 11 is prepared, comprising a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The substrate 11 is transparent.

[0288] Next, as Figure 19B As shown, a base coating 15 is formed on the substrate 11. At this time, the base coating 15 can also be formed over approximately the entire area of ​​the first surface 11a of the substrate 11. Methods for forming the base coating 15 include roller coating, gravure coating, gravure reverse coating, microgravure coating, slot die coating, mold coating, doctor blade coating, inkjet coating, dispenser coating, mating coating, spraying, screen printing, offset printing, and flexographic printing.

[0289] Next, a mesh wiring layer 20 is formed on the base layer 15, comprising a plurality of first-direction wirings 21 and a plurality of second-direction wirings 22 connecting the plurality of first-direction wirings 21.

[0290] At this point, firstly, as Figure 19C As shown, a resin film 505 is laminated over approximately the entire surface area of ​​the base coating 15. This resin film 505 is used to form the black layers 21d and 22d. The resin film 505 may, for example, be formed using a resin containing dyes or pigments, and by, for example, gravure printing. The thickness of the resin film 505 can be 0.2 μm or more and 1.0 μm or less.

[0291] like Figure 19D As shown, a first metal film 501 is laminated over approximately the entire surface area of ​​the resin film 505. This first metal film 501 is used to form the first metal layers 21a and 22a. The first metal film 501 can also be formed, for example, by sputtering. The thickness of the first metal film 501 can be 10 nm or more and 1000 nm or less. In this embodiment, the first metal film 501 may also contain copper.

[0292] Next, as Figure 19E As shown, a second metal film 502 is stacked on a first metal film 501. This second metal film 502 is used to form the second metal layers 21b and 22b. Alternatively, the first metal film 501 can be used as a seed layer, and the second metal film 502 can be formed using electroplating. The thickness of the second metal film 502 can be 50 nm or more and 4990 nm or less. In this embodiment, the second metal film 502 may also contain copper. Furthermore, the above-described process of stacking the first metal film 501 ( Figure 19D This can also be performed in a vacuum chamber (not shown). On the other hand, the process of laminating the second metal film 502 ( Figure 19E It can also be performed outside a vacuum chamber (not shown).

[0293] Next, as Figure 19F As shown, a photocurable insulating resist 53 is supplied to approximately the entire surface area of ​​the second metal film 502. Examples of such photocurable insulating resist 53 include organic resins such as acrylic resins and epoxy resins.

[0294] Next, as Figure 19G As shown, the insulating layer 54 is formed by photolithography. In this case, the insulating layer 54 (resist pattern) is formed by patterning a photocurable insulating resist 53 using photolithography. At this time, the insulating layer 54 is formed such that the second metal film 502 corresponding to the first direction wiring 21 and the second direction wiring 22 is exposed.

[0295] Next, as Figure 19HAs shown, the second metal film 502, the first metal film 501, and the resin film 505 on the first surface 11a of the substrate 11, located in the portion not covered by the insulating layer 54, are removed. At this time, a wet treatment using strong acids such as ferric chloride, copper chloride, sulfuric acid / hydrochloric acid, persulfate, hydrogen peroxide, or aqueous solutions thereof, or combinations thereof, is performed to etch the second metal film 502, the first metal film 501, and the resin film 505 so that the first surface 11a of the substrate 11 is exposed. In this wet treatment, the liquid used for the second metal film 502 and the first metal film 501 and the liquid used for the resin film 505 can be different. Furthermore, although the detailed process is not shown, as another example, in order to obtain... Figure 19H The same pattern shown on the resin film 505 can also be pre-patterned on the resin film 505 using photolithography. Furthermore, other layers can be laminated on the resin film 505 in subsequent processes.

[0296] Next, as Figure 19I As shown, the insulating layer 54 is removed. In this case, the insulating layer 54 on the second metal film 502 is removed by performing a wet treatment using a permanganate solution or N-methyl-2-pyrrolidone, an acid or alkali solution, or a dry treatment using oxygen plasma.

[0297] Thus, a wiring substrate 10 is obtained, comprising a substrate 11, a base coating 15 disposed on a first surface 11a of the substrate 11, and a mesh wiring layer 20 disposed on the base coating 15. In this case, the mesh wiring layer 20 includes first-direction wiring 21 and second-direction wiring 22. At this time, the power supply section 40 may also be formed from a portion of the first metal film 501 and the second metal film 502.

[0298] Then, across Figure 14 The first transparent adhesive layer 95 and the second transparent adhesive layer 96 shown are stacked on the wiring substrate 10 to form a display device 61, thereby obtaining an image display device 60 having the wiring substrate 10 and the display device 61 stacked on the wiring substrate 10.

[0299] Next, the function of this embodiment, which is constructed in this way, will be explained.

[0300] like Figure 13 and Figure 14 As shown, the wiring substrate 10 is assembled onto the image display device 60, which has a display device 61. At this time, the wiring substrate 10 is disposed on the display device 61. The grid 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. Thus, radio waves of a predetermined frequency can be transmitted and received via the grid wiring layer 20, thereby enabling communication using the image display device 60.

[0301] According to this embodiment, the mesh wiring layer 20 has a first-direction wiring 21 and a second-direction wiring 22. Furthermore, the first-direction wiring 21 and the second-direction wiring 22 each include: black layers 21d and 22d containing resin; first metal layers 21a and 22a disposed on the black layers 21d and 22d; and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. Thus, since the first-direction wiring 21 and the second-direction wiring 22 include black layers 21d and 22d, the reflection of visible light incident on the mesh wiring layer 20 from the substrate 11 side can be suppressed. Therefore, the mesh wiring layer 20 can be made difficult to distinguish with the naked eye.

[0302] Furthermore, when the black layers 21d and 22d contain resin, the linewidths W1 and W2 can be narrowed, so that the linewidth W1 of the first-direction wiring 21 and the linewidth W2 of the second-direction wiring 22 are both 5.0 μm or less. That is, for example, when the black layer is made of metal, during the formation of the first-direction wiring 21, the black layer and the portion between the black layer and the first metal layers 21a and 22a may sometimes be accidentally etched. In this case, a break in the first-direction wiring 21 may occur (so-called wiring breakage). In addition, due to the difference between the etching rate of the black layer and the etching rate of the first metal layers 21a and 22a, the first metal layers 21a and 22a may be accidentally removed, or the black layer may be accidentally removed. In other words, for example, when the black layer is made of metal, it may be difficult to control the shape of each layer. In contrast, by containing resin in the black layers 21d and 22d (resin film 505), the acid resistance of the resin film 505 can be improved. Therefore, when forming the first-direction wiring 21 and the second-direction wiring 22 by etching, the black layers 21d and 22d are removed by wet processing with an alkaline solution or the like, or by dry processing, thereby making it easier to control the shape of each layer. As a result, the linewidths W1 and W2 can be narrowed, so that the linewidth W1 of the first-direction wiring 21 and the linewidth W2 of the second-direction wiring 22 are both 5.0 μm or less. As a result, the mesh wiring layer 20 becomes difficult to be seen with the naked eye.

[0303] Furthermore, according to this embodiment, the mesh wiring layer 20 includes black layers 21d and 22d, first metal layers 21a and 22a disposed on the black layers 21d and 22d, and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. Thus, by forming the first metal layers 21a and 22a on the black layers 21d and 22d, and forming the second metal layers 21b and 22b on the first metal layers 21a and 22a, the adhesion between the black layers 21d and 22d and the first metal layers 21a and 22a, as well as the adhesion between the first metal layers and the second metal layers, can be improved. Therefore, the adhesion between the substrate 11 and the mesh wiring layer 20 can be improved.

[0304] Furthermore, according to this embodiment, the mesh wiring layer 20 has first metal layers 21a and 22a disposed on the black layers 21d and 22d, and second metal layers 21b and 22b disposed on the first metal layers 21a and 22a. This effectively increases the height H1 of the first-direction wiring 21 and the height H2 of the second-direction wiring 22. Consequently, the resistance values ​​of the first-direction wiring 21 and the second-direction wiring 22 can be reduced.

[0305] Furthermore, according to this embodiment, the wiring substrate 10 includes a substrate 11, a base coating 15 disposed on the substrate 11, and a mesh wiring layer 20 disposed on the base coating 15. Additionally, the substrate 11 is transparent. Furthermore, the mesh wiring layer 20 has a mesh-like pattern formed by conductor portions that are formed as opaque conductive layers and a plurality of openings 23. Therefore, the transparency of the wiring substrate 10 is ensured. As a result, when the wiring substrate 10 is disposed on the display device 61, the display device 61 can be visually identified from the openings 23 of the mesh wiring layer 20, without obstructing the visual recognizability of the display device 61.

[0306] Next, a modified example of the wiring substrate of the second embodiment will be described.

[0307] Figure 20 and Figure 21 A first variation of the wiring substrate according to the second embodiment is shown. Figure 20 and Figure 21 The variant shown differs from the one described above in that the wiring substrate 10 does not have a base coating 15; otherwise, the structure is the same as described above. Figures 13 to 19I The shapes shown are roughly the same. Figure 20 and Figure 21 In the middle, to and Figures 13 to 19I Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0308] exist Figure 20 and Figure 21In the wiring substrate 10 shown, no base coating 15 is provided on the substrate 11. In this case, for example, the black layers 21d and 22d serve to improve the adhesion between the mesh wiring layer 20 and the substrate 11. In this case, the adhesion between the substrate 11 and the mesh wiring layer 20 can also be improved.

[0309] Figure 22 and Figure 23 A second variation of the wiring substrate according to the second embodiment is shown. Figure 22 and Figure 23 The variant shown differs from the one described above in that the wiring substrate 10 also has a dark layer 18 covering the mesh wiring layer 20; otherwise, the structure is the same as described above. Figures 13 to 21 The shapes shown are roughly the same. Figure 22 and Figure 23 In the middle, to and Figures 13 to 21 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0310] exist Figure 22 and Figure 23 In the wiring substrate 10 shown, the mesh wiring layer 20 is covered by a dark layer 18. This dark layer 18 is used to make the mesh wiring layer 20 difficult to see with the naked eye by suppressing the reflection of visible light caused by the mesh wiring layer 20. The dark layer 18 covers the sides of the first metal layers 21a and 22a, and the surfaces and sides of the second metal layers 21b and 22b in the mesh wiring layer 20. In other words, the dark layer 18 surrounds the first metal layers 21a and 22a and the second metal layers 21b and 22b in such a way that it covers the entire area of ​​the first metal layers 21a and 22a and the second metal layers 21b and 22b except for the back surfaces of the first metal layers 21a and 22a. In the illustrated example, black layers 21d and 22d are provided on the back surface (negative side in the Z direction) of the dark layer 18, covering the back surface of the dark layer 18. Furthermore, although not shown in the diagram, it is also possible that the black layers 21d and 22d do not cover the back side of the dark layer 18, and the dark layer 18 covers the sides of the black layers 21d and 22d. Alternatively, the dark layer 18 may cover the entire area of ​​the power supply section 40 except for the back side of the power supply section 40.

[0311] The dark layer 18 can also be a dark layer, such as black. Alternatively, the dark layer 18 can also be a layer with a roughened surface.

[0312] The surface roughness Sa of the dark layer 18 can be 5 nm or more and 100 nm or less. By making the surface roughness Sa of the dark layer 18 5 nm or more, the reflection of visible light on the surface of the dark layer 18 can be suppressed. Therefore, the mesh wiring layer 20 covered by the dark layer 18 is not easily visible to the naked eye of an observer. By making the surface roughness Sa of the dark layer 18 100 nm or less, the haze value of the dark layer 18 can be suppressed from becoming too high. As a result, the presence of the dark layer 18 is difficult for an observer to detect. Therefore, the mesh wiring layer 20 covered by the dark layer 18 is not easily visible to the naked eye of an observer. In this case, the surface roughness Sa is determined using a laser microscope (KEYENCE Corporation, VK-X 1000) based on ISO 25178.

[0313] Regarding the dark layer 18, for example, it can be formed by performing a darkening treatment (blackening treatment) on a portion of the metal material constituting the mesh wiring layer 20 or the power supply section 40, thereby forming the dark layer 18 as a part of the mesh wiring layer 20 or the power supply section 40. In this case, the dark layer 18 can be formed as a layer composed of metal oxides or metal sulfides. Alternatively, the dark layer 18 can also be formed on the surface of the mesh wiring layer 20 or the power supply section 40 as a coating of dark material or a plating layer of nickel or chromium. Furthermore, the dark layer 18 can also be formed by roughening the surface of the mesh wiring layer 20 or the power supply section 40.

[0314] As described above, the dark layer 18 covers the sides of the first metal layers 21a and 22a, and the surfaces and sides of the second metal layers 21b and 22b in the mesh wiring layer 20. On the other hand, as... Figure 24 As shown, there exists a situation where a dark layer 18, formed by a darkening treatment (blackening treatment) of a portion of the metallic material, covers the back side of the first metal layers 21a and 22a. In this case, light is easily reflected orthogonally at the front, sides, and back of the dark layer 18, as well as the front and back of the base layer 15. Thus, light undergoes orthogonal reflection at various points, thereby... Figure 25 As shown by dashed line A, there exists a situation where contrast increases at a specific wavelength due to interference of reflected light. In this case, coloration is very easily identified at the wavelengths where contrast is high. This easily leads to so-called iridic anomalies caused by the reflection spectrum. Furthermore, when viewing an object from an oblique angle, as a result of the increased effective optical path length, a phenomenon known to occur where the spectrum shifts towards shorter wavelengths is observed. In this case, the reflection spectrum with high reflectivity in the infrared region shifts towards shorter wavelengths and enters the visible light region. Thus, through thin-film interference, the wavelength shifts towards shorter wavelengths based on the angle of observation. Therefore, when viewing an object from an oblique angle, coloration is much easier to identify compared to viewing the object from the front.

[0315] Furthermore, as described above, the image display device laminate 70, constructed from the wiring substrate 10, is sometimes assembled into a head-mounted display (smart glasses). In this case, such as Figure 26 As shown, for example, the image display device laminate 70 can be assembled onto the head-mounted display 90 by mounting it onto the frame 91. In this case, there is also a possibility that the contrast becomes higher at a specific wavelength due to light interference. In this case, as... Figure 26 and Figure 27 As shown, a so-called iridescent asymmetry R, ​​caused by the reflectance spectrum, is easily generated. This iridescent asymmetry R is not visually perceptible to the wearer of the head-mounted display 90, but rather to the observer of the head-mounted display being worn. In particular, the iridescent asymmetry R is more easily perceived as a rainbow pattern by the observer in the dark.

[0316] In contrast, in this modified example, the first directional wiring 21 and the second directional wiring 22 include black layers 21d and 22d containing resin. This suppresses reflections of light incident from the substrate 11 side onto the mesh wiring layer 20, as well as reflections at the sides of the black layers 21d and 22d. Therefore, interference of reflected light can be suppressed. As a result, as... Figure 25 As shown by solid line B, it can suppress the increase in contrast at a specific wavelength. Therefore, it can suppress the generation of so-called iridescent unevenness.

[0317] In this case, the 5° positive reflectance of the black layers 21d and 22d at a wavelength of 700nm can also be lower than that of the dark layer 18. In this case, light reflection can also be suppressed, and the increase in contrast at a specific wavelength can be suppressed. Therefore, the generation of so-called iridescent unevenness can be suppressed. Furthermore, in Figure 25 In the diagram, dashed line C represents the 5° positive reflectance of the dark layer 18, and dashed line D represents the 5° positive reflectance of the black layers 21d and 22d. The 5° positive reflectance is measured as follows: First, a wiring substrate 10 is prepared as the measurement sample. Next, to prevent back reflection from the measurement sample, black adhesive tape (manufactured by Teraoka Corporation) is attached to the back side of the measurement sample. Then, the 5° positive reflectance is measured using a Shimadzu UV-3100 spectrophotometer.

[0318] The 5° orthoreflectance spectrum of the dark layer 18 and the 5° orthoreflectance spectrum of the black layers 21d and 22d can be different in the visible light wavelength region. In this embodiment, the first directional wiring 21 and the second directional wiring 22 include both the dark layer 18 and the black layers 21d and 22d. Moreover, the reflection spectra of the dark layer 18 and the black layers 21d and 22d are different. Such first directional wiring 21 and second directional wiring 22 are less likely to cause interference that enhances the reflected light at specific wavelengths. Therefore, the first directional wiring 21 and second directional wiring 22 of this embodiment can suppress iridic non-uniformity.

[0319] In this way, by also including a dark layer 18 covering the mesh wiring layer 20 on the wiring substrate 10, the reflection of visible light on the surface of the dark layer 18 can be suppressed. Therefore, the mesh wiring layer 20 covered by the dark layer 18 can be made difficult for an observer to see with the naked eye.

[0320] Figure 28 and Figure 29 A third variation of the wiring substrate according to the second embodiment is shown. Figure 28 and Figure 29 The variant shown differs from the one described above in that the mesh wiring layer 20 does not include black layers 21d and 22d; otherwise, the structure is the same as described above. Figures 13 to 27 The shapes shown are roughly the same. Figure 28 and Figure 29 In the middle, to and Figures 13 to 27 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0321] exist Figure 28 and Figure 29 In the wiring substrate 10 shown, the mesh wiring layer 20 does not include the black layers 21d and 22d disposed on the base coating layer 15. That is, as Figure 28 As shown, the first directional wiring 21 does not include a black layer 21d. In this case, the first directional wiring 21 includes a first metal layer 21a disposed on the base coating 15 and a second metal layer 21b disposed on the first metal layer 21a. Additionally, as... Figure 29 As shown, the second-direction wiring 22 does not include a black layer 22d. In this case, the second-direction wiring 22 includes a first metal layer 22a disposed on the base coating 15 and a second metal layer 22b disposed on the first metal layer 22a.

[0322] In this variation, the base coating 15 can also be a dark layer, such as black. The base coating 15 may also contain a black colorant. In this case, the base coating 15 may contain dyes or pigments as the black colorant. Specifically, the base coating 15 may contain pigments such as carbon black or titanium black. Thus, by making the base coating 15 a dark layer, the reflection of visible light incident on the mesh wiring layer 20 from the substrate 11 side can be suppressed. Therefore, the mesh wiring layer 20 can be made difficult to see with the naked eye.

[0323] Figure 30 and Figure 31 A fourth variation of the wiring substrate of the second embodiment is shown. Figure 30 and Figure 31 The difference in the variant shown is that, similar to the first variant of the first embodiment, a dummy wiring layer 30 is provided around the mesh wiring layer 20. Apart from this, the other structures are the same as described above. Figures 13 to 29 The shapes shown are roughly the same. Figure 30 and Figure 31 In the middle, to and Figures 13 to 29 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0324] exist Figure 30 In the wiring substrate 10 shown, a dummy wiring layer 30 is provided around the grid wiring layer 20. This dummy wiring layer 30 is different from the grid wiring layer 20 and does not actually function as an antenna.

[0325] like Figure 31 As shown, the dummy wiring layer 30 is formed by repeating dummy wirings 30a with a defined unit pattern shape. That is, the dummy wiring layer 30 includes multiple dummy wirings 30a of the same shape, each dummy wiring 30a being electrically independent of the grid wiring layer 20 (first direction wiring 21 and second direction wiring 22). Furthermore, the multiple dummy wirings 30a are regularly arranged throughout the entire area of ​​the dummy wiring layer 30. The multiple dummy wirings 30a are separated from each other in the planar direction and are protruding from the substrate 11. That is, each dummy wiring 30a is electrically independent of the grid wiring layer 20, the power supply section 40, and other dummy wirings 30a. The shape of each dummy wiring 30a is approximately L-shaped when viewed from above.

[0326] In this case, the dummy wiring 30a has a unit pattern shape that makes the aforementioned mesh wiring layer 20 (see reference) Figure 16 The shape is formed by the absence of a portion of the ) . As a result, the difference between the mesh wiring layer 20 and the dummy wiring layer 30 is difficult to identify visually, and the mesh wiring layer 20 disposed on the substrate 11 is difficult to see.

[0327] like Figure 31As shown, the dummy wiring 30a extends parallel to either the first-direction wiring 21 or the second-direction wiring 22. Specifically, the dummy wiring 30a includes a first portion 31a extending parallel to the first-direction wiring 21 and a second portion 32a extending parallel to the second-direction wiring 22. The first portion 31a has a shape in which a portion of the first-direction wiring 21 is missing. Furthermore, the second portion 32a has a shape in which a portion of the second-direction wiring 22 is missing. Since the other structures of the first portion 31a and the second portion 32a are the same as those of the first-direction wiring 21 and the second-direction wiring 22, detailed descriptions are omitted here. Thus, by extending the dummy wiring 30a parallel to either the first-direction wiring 21 or the second-direction wiring 22, the mesh wiring layer 20 disposed on the substrate 11 becomes more difficult to see. The aperture ratio of the dummy wiring layer 30 can be the same as or different from that of the mesh wiring layer 20. Even when the aperture ratio of the dummy routing layer 30 is different from that of the mesh routing layer 20, the aperture ratio of the dummy routing layer 30 can still be close to that of the mesh routing layer 20.

[0328] In this way, by providing a dummy wiring layer 30 that is electrically independent of the mesh wiring layer 20 around the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made unclear. As a result, the mesh wiring layer 20 is difficult to see on the surface of the image display device 60, and it is difficult for the user of the image display device 60 to identify the mesh wiring layer 20 with the naked eye.

[0329] Figure 32 and Figure 33 A fifth variation of the wiring substrate according to the second embodiment is shown. Figure 32 and Figure 33 The difference in the variant shown is that, similar to the second variant of the first embodiment, two or more dummy wiring layers 30A and 30B with different aperture ratios are provided around the mesh wiring layer 20. Apart from this, the other structures are the same as described above. Figures 13 to 31 The shapes shown are roughly the same. Figure 32 and Figure 33 In the middle, to and Figures 13 to 31 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0330] exist Figure 32In the wiring substrate 10 shown, multiple (in this case, two) dummy wiring layers 30A and 30B (first dummy wiring layer 30A and second dummy wiring layer 30B) with different aperture ratios are arranged around the grid wiring layer 20. Specifically, the first dummy wiring layer 30A is arranged around the grid wiring layer 20, and the second dummy wiring layer 30B is arranged around the first dummy wiring layer 30A. These dummy wiring layers 30A and 30B are different from the grid wiring layer 20 and do not actually function as antennas.

[0331] like Figure 33 As shown, the first dummy wiring layer 30A is formed by repeating dummy wirings 30a1 with a defined unit pattern shape. The second dummy wiring layer 30B is formed by repeating dummy wirings 30a2 with a defined unit pattern shape. That is, dummy wiring layers 30A and 30B each contain multiple dummy wirings 30a1 and 30a2 of the same shape, and each dummy wiring 30a1 and 30a2 is electrically independent from the grid wiring layer 20. The dummy wirings 30a1 and 30a2 are regularly arranged throughout the entire area of ​​the dummy wiring layers 30A and 30B, respectively. Each dummy wiring 30a1 and 30a2 is separated from each other in the planar direction and is arranged protrudingly on the substrate 11. Each dummy wiring 30a1 and 30a2 is electrically independent from the grid wiring layer 20, the power supply section 40, and other dummy wirings 30a1 and 30a2. The shape of each dummy wiring 30a1 and 30a2 is approximately L-shaped when viewed from above.

[0332] In this case, the dummy wiring 30a1 and 30a2 have a unit pattern shape that makes the aforementioned mesh wiring layer 20 (see reference) Figure 16 The shape is formed by the absence of a portion of the mesh wiring layer 20. Therefore, 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, is difficult to visually identify, making the mesh wiring layer 20 disposed on the substrate 11 difficult to see. For example... Figure 33 As shown, dummy wirings 30a1 and 30a2 extend parallel to either the first direction wiring 21 or the second direction wiring 22. Specifically, dummy wiring 30a1 includes a first portion 31a1 extending parallel to the first direction wiring 21 and a second portion 32a1 extending parallel to the second direction wiring 22. Dummy wiring 30a2 includes a first portion 31a2 extending parallel to the first direction wiring 21 and a second portion 32a2 extending parallel to the second direction wiring 22.

[0333] Furthermore, 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 linewidth of each dummy wiring 30a1 is the same as the linewidth of each dummy wiring 30a2, but this is not a limitation; the linewidth of each dummy wiring 30a1 may also be larger than the linewidth of each dummy wiring 30a2. Moreover, the other structures of the dummy wirings 30a1 and 30a2 are the same as those of the dummy wiring 30a in the fourth variation, therefore detailed descriptions are omitted here.

[0334] In this modified example, the aperture ratio of the mesh wiring layer 20 and the two or more dummy wiring layers 30A and 30B can also gradually increase from the mesh wiring layer 20 toward the dummy wiring layers 30A and 30B further away from the mesh wiring layer 20. In other words, the aperture ratio of each dummy wiring layer can also gradually increase from a position close to the mesh wiring layer 20 toward a position further away from the mesh wiring layer 20. In this case, the aperture ratio of the first dummy wiring layer 30A can also be larger than the aperture ratio of the mesh wiring layer 20. The aperture ratio of the second dummy wiring layer 30B can be larger than the aperture ratio of the first dummy wiring layer 30A. As a result, the outer edges of the mesh wiring layer 20 and the dummy wiring layers 30A and 30B can be made less clear. Therefore, it is more difficult to see the mesh wiring layer 20 on the surface of the image display device 60.

[0335] In this way, by configuring dummy wiring layers 30A and 30B that are electrically independent of the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made less distinct. This makes the mesh wiring layer 20 difficult to see on the surface of the image display device 60, and makes it difficult for the user of the image display device 60 to visually identify the mesh wiring layer 20. Furthermore, three or more dummy wiring layers with different aperture ratios can be provided around the mesh wiring layer 20.

[0336] Figure 34 A sixth variation of the wiring substrate of the second embodiment is shown. Figure 34 The difference between the variant shown and the one described is that, similar to the third variant of the first embodiment, the planar shape of the mesh wiring layer 20 is different, while the other structures are the same as described above. Figures 13 to 33 The shapes shown are roughly the same. Figure 34 In the middle, to and Figures 13 to 33 Parts with the same shape are labeled with the same number and detailed descriptions are omitted.

[0337] Figure 34 This is an enlarged top view showing the mesh wiring layer 20 of the sixth variant example. Figure 34In the diagram, the first direction wiring 21 and the second direction wiring 22 intersect at an angle (not at a right angle), and the shape of each opening 23 is rhomboid when viewed from above. Although the first direction wiring 21 and the second direction wiring 22 are not parallel to the X and Y directions respectively, either the first direction wiring 21 or the second direction wiring 22 can be parallel to either the X or Y direction.

[0338] The various constituent elements disclosed in the above embodiments and modifications can also be appropriately combined as needed. Alternatively, several constituent elements can be deleted from all the constituent elements shown in the above embodiments and modifications.

Claims

1. A wiring substrate comprising: A substrate comprising a first surface and a second surface located on the opposite side of the first surface; A base coating layer disposed on the first surface of the substrate; and A mesh wiring layer is disposed on the base layer. The substrate is transparent. The mesh wiring layer has: A first dark layer is disposed on the base layer; A first metal layer is disposed on the first dark layer; as well as A second metal layer is disposed on the first metal layer. The surface roughness Sa of the first dark layer is greater than 5 nm and less than 200 nm.

2. The wiring substrate according to claim 1, wherein, The wiring substrate further comprises a second dark layer covering the mesh wiring layer, wherein the surface roughness Sa of the second dark layer is greater than 5 nm and less than 100 nm.

3. The wiring substrate according to claim 1 or 2, wherein, The first metal layer and the second metal layer have different crystallization properties. The second metal layer has a crystallization property where the diffraction angle 2θ of the (111) plane measured using CuKα rays as an X-ray source is less than 43.4°.

4. The wiring substrate according to any one of claims 1 to 3, wherein, The dielectric loss tangent of the substrate is below 0.

002.

5. The wiring substrate according to any one of claims 1 to 4, wherein, When the wiring substrate is bent 180° around a cylinder with a diameter of 1 mm and then stretched 100 times, the increase in resistance of the mesh wiring layer is less than 20%.

6. The wiring substrate according to any one of claims 1 to 5, wherein, The wiring substrate has millimeter-wave transceiver capabilities, and the mesh wiring layer is configured as an array antenna.

7. The wiring substrate according to any one of claims 1 to 6, wherein, A dummy wiring layer, electrically independent of the mesh wiring layer, is provided around the mesh wiring layer.

8. The wiring substrate according to claim 7, wherein, Multiple dummy routing layers are provided, and the aperture ratio of the mesh routing layer and the aperture ratio of the dummy routing layer increase in stages from the mesh routing layer toward the dummy routing layer away from the mesh routing layer.

9. An image display device comprising: The wiring substrate according to any one of claims 1 to 8; and The display device is stacked on the wiring substrate.

10. A wiring substrate comprising: A substrate comprising a first surface and a second surface located opposite to the first surface; and A mesh wiring layer is disposed on the first surface of the substrate. The substrate is transparent. The mesh wiring layer has wiring. The wiring includes: A black layer containing resin; A first metal layer is disposed on the black layer; as well as A second metal layer is disposed on the first metal layer. The wiring width is less than 5.0 μm.

11. The wiring substrate according to claim 10, wherein, The wiring substrate also includes an undercoat layer disposed between the substrate and the mesh wiring layer.

12. The wiring substrate according to claim 10 or 11, wherein, The thickness of the black layer is greater than 0.2 μm and less than 1.0 μm.

13. The wiring substrate according to any one of claims 10 to 12, wherein, The black layer contains dyes or pigments.

14. The wiring substrate according to any one of claims 10 to 13, wherein, The first metal layer and the second metal layer have different crystallization properties. The second metal layer has a crystallization property where the diffraction angle 2θ of the (111) plane measured using CuKα rays as an X-ray source is less than 43.4°.

15. The wiring substrate according to any one of claims 10 to 14, wherein, The dielectric loss tangent of the substrate is below 0.

002.

16. The wiring substrate according to any one of claims 10 to 15, wherein, When the wiring substrate is bent 180° around a cylinder with a diameter of 1 mm and then stretched 100 times, the increase in resistance of the mesh wiring layer is less than 20%.

17. The wiring substrate according to any one of claims 10 to 16, wherein, The wiring substrate has millimeter-wave transceiver capabilities, and the mesh wiring layer is configured as an array antenna.

18. The wiring substrate according to any one of claims 10 to 17, wherein, A dummy wiring layer, electrically independent of the mesh wiring layer, is provided around the mesh wiring layer.

19. The wiring substrate according to claim 18, wherein, Multiple dummy routing layers are provided, and the aperture ratio of the mesh routing layer and the aperture ratio of the dummy routing layer increase in stages from the mesh routing layer toward the dummy routing layer away from the mesh routing layer.

20. The wiring substrate according to any one of claims 10 to 19, wherein, The wiring substrate also has a dark layer covering the mesh wiring layer.

21. The wiring substrate according to claim 20, wherein, The black layer has a lower 5° positive reflectance at a wavelength of 700nm than the dark layer.

22. The wiring substrate according to claim 20 or 21, wherein, The 5° orthoreflectance spectrum of the dark layer and the 5° orthoreflectance spectrum of the black layer are different in the visible light wavelength region.

23. A wiring substrate comprising: A substrate comprising a first surface and a second surface located on the opposite side of the first surface; A base coating layer disposed on the first surface of the substrate; and A mesh wiring layer is disposed on the base layer. The substrate is transparent. The base coating is a dark-colored layer. The mesh wiring layer has wiring. The wiring includes: A first metal layer disposed on the base layer; and A second metal layer is disposed on the first metal layer.

24. An image display device comprising: The wiring substrate according to any one of claims 10 to 23; and The display device is stacked on the wiring substrate.

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