Module, laminate for image display device, image display device, and method for manufacturing the module

Abstract

The present invention provides a module that suppresses a decrease in electrical connectivity between a power supply line and a power supply unit, a laminate for an image display device, and an image display device. [Solution] Module 80A comprises a substrate 11 including a first surface 11a and a second surface 11b located opposite the first surface 11a, a wiring board 10 having a mesh wiring section 20 disposed on the first surface 11a of the substrate 11 and a power supply section 40 electrically connected to the mesh wiring section 20, and a power supply line 85 electrically connected to the power supply section 40 via an anisotropic conductive film 85c containing a plurality of conductive particles 85d. The wiring board 10 has an electromagnetic wave transmission and reception function. The substrate 11 is transparent. The mesh wiring section 20 is configured as an antenna. The average particle diameter of the conductive particles 85d is 3 μm or more and 20 μm or less.

Description

[Technical Field]

[0001] Embodiments of this disclosure relate to a module, a laminate for an image display device, an image display device, and a method for manufacturing the module. [Background technology]

[0002] Currently, mobile devices such as smartphones and tablets are becoming more sophisticated, smaller, thinner, and lighter. Because these devices utilize multiple communication bands, they require multiple antennas corresponding to each band. For example, mobile devices are equipped with multiple antennas, including antennas for telephone communication, Wi-Fi (Wireless Fidelity), 3G (Generation), 4G (Generation), LTE (Long Term Evolution), Bluetooth (registered trademark), and NFC (Near Field Communication). However, with the miniaturization of mobile devices, the space available for antenna installation is limited, restricting the design flexibility of antennas. Furthermore, because antennas are integrated into a limited space, radio wave sensitivity is not always satisfactory.

[0003] For this reason, film antennas that can be mounted on the display area of ​​mobile devices have been developed. In this film antenna, an antenna pattern is formed on a transparent substrate, and the antenna pattern is formed by a mesh-like conductive mesh layer consisting of a conductive part as a part that forms an opaque conductive layer and a number of openings as a non-formed part. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-66610 [Patent Document 2] Patent No. 5636735 specification [Patent Document 3] Patent No. 5695947 specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Incidentally, in film antennas, a feed line is connected to the feed section, which electrically connects the conductive mesh layer to external equipment. In this case, it is necessary to suppress the deterioration of electrical connectivity between the feed section and the feed line.

[0006] This embodiment aims to provide a module, a laminate for an image display device, an image display device, and a method for manufacturing the module that can suppress a decrease in electrical connectivity between the power supply line and the power supply unit. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a module comprising a substrate including a first surface and a second surface located opposite to the first surface, a wiring board having a mesh wiring portion disposed on the first surface of the substrate and a power supply portion electrically connected to the mesh wiring portion, and a power supply line electrically connected to the power supply portion via an anisotropic conductive film containing a plurality of conductive particles, wherein the wiring board has an electromagnetic wave transmission and reception function, the substrate is transparent, the mesh wiring portion is configured as an antenna, and the average particle diameter of the conductive particles is 3 μm or more and 20 μm or less.

[0008] A second aspect of this disclosure is a module according to the first aspect described above, in which, of the plurality of conductive particles, 20% of the conductive particles are excluded in order from the largest particle diameter, and 20% of the conductive particles are excluded in order from the smallest particle diameter, and in the remaining 60% of the conductive particles, the value obtained by subtracting the minimum value from the maximum value of the particle diameter may be 60% or less of the average particle diameter.

[0009] A third aspect of the present disclosure is a module according to the first or second aspect described above, wherein the wiring board may have a millimeter-wave transmitting and receiving function, and the mesh wiring section may be configured as an array antenna.

[0010] A fourth aspect of this disclosure is that, in the module according to the first to third aspects described above, the thickness of the anisotropic conductive film may be 3 μm or more and 20 μm or less.

[0011] A fifth aspect of the present disclosure is that, in each of the modules according to the first to fourth aspects described above, a first oxide film may be formed on the surface of the power supply portion, and the conductive particles may penetrate the first oxide film.

[0012] A sixth aspect of the present disclosure is a module according to each of the first to fifth aspects described above, wherein the power supply line may have a base material and a metal wiring portion laminated on the base material, a second oxide film may be formed on the surface of the metal wiring portion, and the conductive particles may penetrate the second oxide film.

[0013] A seventh aspect of this disclosure is that, in each of the modules according to the first to sixth aspects described above, the distance between the mesh wiring portions may be 1 mm or more and 5 mm or less.

[0014] An eighth aspect of this disclosure is that, in each of the modules according to the first to seventh aspects described above, a dummy wiring section electrically independent from the mesh wiring section may be provided around the mesh wiring section.

[0015] A ninth aspect of the present disclosure is that in the module according to the eighth aspect described above, a plurality of dummy wiring sections may be provided, and the opening ratio of the mesh wiring section and the dummy wiring section may increase in stages from the mesh wiring section toward the dummy wiring section which is further away from the mesh wiring section.

[0016] The tenth aspect of the present disclosure is a laminate for an image display device, comprising a module according to each of the first aspect to the ninth aspect described above, a first adhesive layer located on the first surface side of the substrate, and a second adhesive layer located on the second surface side of the substrate, wherein a partial region of the substrate is disposed in a partial region between the first adhesive layer and the second adhesive layer.

[0017] The eleventh aspect of the present disclosure is an image display device, comprising a laminate for an image display device according to the tenth aspect described above, and a display device laminated on the laminate for an image display device.

[0018] The twelfth aspect of the present disclosure is a method for manufacturing a module, comprising the steps of: preparing a substrate including a first surface and a second surface located on the opposite side of the first surface; manufacturing a wiring substrate by forming a mesh wiring portion and a power supply portion electrically connected to the mesh wiring portion on the first surface of the substrate; and electrically connecting a power supply line to the power supply portion through an anisotropic conductive film including a plurality of conductive particles, wherein the wiring substrate has an electromagnetic wave transmission and reception function, the substrate has transparency, the mesh wiring portion is configured as an antenna, and the average particle diameter of the conductive particles is 3 μm or more and 20 μm or less.

Advantages of the Invention

[0019] According to an embodiment of the present disclosure, it is possible to suppress a decrease in electrical connectivity between a power supply line and a power supply portion.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a plan view showing an image display device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view (a cross-section taken along line II-II in FIG. 1) showing an image display device according to an embodiment. [Figure 3] FIG. 3 is a plan view showing a wiring substrate according to an embodiment. [Figure 4]Figure 4 is an enlarged plan view showing the mesh wiring section of a wiring board according to one embodiment. [Figure 5] Figure 5 is a cross-sectional view (VV line cross-section in Figure 4) showing a wiring board according to one embodiment. [Figure 6] Figure 6 is a cross-sectional view (cross-sectional view along line VI-VI in Figure 4) showing a wiring board according to one embodiment. [Figure 7] Figure 7 is a cross-sectional view showing a module according to one embodiment. [Figure 8] Figures 8(a)-(f) are cross-sectional views showing a method for manufacturing a wiring board according to one embodiment. [Figure 9] Figures 9(a)-(c) are cross-sectional views showing a method for manufacturing a module according to one embodiment. [Figure 10] Figures 10(a)-(c) are cross-sectional views showing a method for manufacturing a laminate for an image display device according to one embodiment. [Figure 11] Figure 11 is a plan view showing a wiring board according to the first modified example. [Figure 12] Figure 12 is an enlarged plan view showing a wiring board according to the first modified example. [Figure 13] Figure 13 is a plan view showing a wiring board according to a second modified example. [Figure 14] Figure 14 is an enlarged plan view showing a wiring board according to the second modified example. [Figure 15] Figure 15 is an enlarged plan view showing the mesh wiring section of the wiring board according to the third modified example. [Modes for carrying out the invention]

[0021] First, an embodiment will be described with reference to Figures 1 to 10. Figures 1 to 10 are diagrams illustrating this embodiment.

[0022] The following figures are schematic representations. Therefore, the size and shape of each part are exaggerated as appropriate for ease of understanding. Furthermore, they can be modified as appropriate without departing from the technical concept. In the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. Also, the numerical values ​​such as dimensions and material names of each component described in this specification are examples of embodiments and are not limiting; they can be selected and used as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, are interpreted to include not only their strict meaning but also substantially equivalent states.

[0023] Furthermore, in the following embodiments, "X direction" refers to the direction parallel to one side of the image display device. "Y direction" refers to the direction perpendicular to the X direction and parallel to the other side of the image display device. "Z direction" refers to the direction perpendicular to both the X and Y directions and parallel to the thickness direction of the image display device. Also, "front surface" refers to the surface on the positive Z direction side, which is the light-emitting surface side of the image display device and faces the observer. "Back surface" refers to the surface on the negative Z direction side, which is the surface opposite to the light-emitting surface and the surface facing the observer of the image display device. In this embodiment, the explanation will take the case where the mesh wiring section 20 has a radio wave transmission and reception function (function as an antenna) as an example, but the mesh wiring section 20 does not necessarily have to have a radio wave transmission and reception function (function as an antenna).

[0024] The configuration of the image display device according to this embodiment will be described with reference to Figures 1 and 2.

[0025] As shown in Figures 1 and 2, the image display device 60 according to this embodiment comprises an image display device laminate 70 and a display device 61 laminated on the image display device laminate 70. As shown in Figure 2, the image display device laminate 70 comprises a wiring board 10, a power supply line 85 electrically connected to the wiring board 10, a first transparent adhesive layer (first adhesive layer) 95, and a second transparent adhesive layer (second adhesive layer) 96. Of these, the wiring board 10 and the power supply line 85 electrically connected to the wiring board 10 constitute a module 80A.

[0026] The wiring board 10 of module 80A comprises a substrate 11, a mesh wiring section 20, and a power supply section 40. As shown in Figure 2, the substrate 11 includes a first surface 11a and a second surface 11b located opposite the first surface 11a. The mesh wiring section 20 is arranged on the first surface 11a of the substrate 11. The power supply section 40 is electrically connected to the mesh wiring section 20. Furthermore, a communication module 63 is arranged on the negative Z-direction side 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.

[0027] In the image display device 60 shown in Figures 1 and 2, radio waves of a predetermined frequency can be transmitted and received via a 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 mobile terminal devices such as smartphones and tablets.

[0028] As shown in Figure 2, the image display device 60 has a light-emitting surface 64. The image display device 60 includes a wiring board 10 located on the side of the light-emitting surface 64 (positive 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 Z-direction) relative to the display device 61.

[0029] 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 be placed on the display device 61. A wiring board 10 is also placed on the display device 61 via a second transparent adhesive layer 96. Note that the display device 61 is not limited to an organic EL display device. For example, the display device 61 may be another display device that has the function of emitting light itself, or it may be a micro-LED display device that includes a micro-LED element (light-emitting element). Also, the display device 61 may be a liquid crystal display device that includes a liquid crystal. A cover glass (surface protective plate) 75 is also placed on the wiring board 10 via a first transparent adhesive layer 95. Note that a polarizing plate (not shown) may be placed between the first transparent adhesive layer 95 and the cover glass 75.

[0030] Next, the laminated image display device 70 will be described in detail. As described above, the laminated image display device 70 comprises a wiring board 10, a power supply line 85, a first adhesive layer 95, and a second adhesive layer 96. Of these, the first transparent adhesive layer 95 is located on the first surface 11a side of the substrate 11 of the wiring board 10. The second transparent adhesive layer 96 is located on the second surface 11b side of the substrate 11 of the wiring board 10. Here, we will first describe the first transparent adhesive layer 95 of the laminated image display device 70. Details of the wiring board 10 and the power supply line 85 will be described later.

[0031] The first transparent adhesive layer 95 is an adhesive layer that directly or indirectly adheres the wiring board 10 to the decorative layer 74 and cover glass 75, which will be described later. 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 be an OCA (Optical Clear Adhesive) layer. An OCA layer is a layer made, for example, as follows: First, a liquid curable adhesive layer composition containing a polymerizable compound is applied to a release film such as polyethylene terephthalate (PET). Next, an OCA sheet is obtained by curing this using, for example, ultraviolet light (UV). After laminating this OCA sheet to the object, the OCA layer is obtained by peeling off the release film. The material of the first transparent adhesive layer 95 may be an acrylic resin, a silicone resin, or a urethane resin. In particular, the first transparent adhesive layer 95 may contain an acrylic resin. In this case, it is preferable that the second transparent adhesive layer 96 contains an acrylic resin. This effectively eliminates the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, thereby more reliably suppressing the reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0032] The first transparent adhesive layer 95 may have a visible light transmittance of 85% or more, and preferably 90% or more. There is no particular upper limit to the visible light transmittance of the first transparent adhesive layer 95, but it may be, for example, 100% or less. By setting the visible light transmittance of the first transparent adhesive layer 95 within the above range, the transparency of the laminate 70 for the image display device can be increased, making the display device 61 of the image display device 60 easier to see. Visible light refers to light rays with a wavelength of 400 nm or more and 700 nm or less. Furthermore, a visible light transmittance of 85% or more means that when the absorbance is measured on the component to be measured (for example, the first transparent adhesive layer 95), the transmittance is 85% or more in the entire wavelength range from 400 nm to 700 nm. Absorbance can be measured using a known spectrophotometer (for example, a spectrometer manufactured by JASCO Corporation: V-670).

[0033] As described above, the wiring board 10 is positioned on the light-emitting surface 64 side relative to the display device 61. In this case, the wiring board 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 board 10 is positioned in a portion of the area between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. In this case, the first transparent adhesive layer 95, the second transparent adhesive layer 96, the display device 61, and the cover glass 75 each have a larger area than the substrate 11 of the wiring board 10. By positioning the substrate 11 of the wiring board 10 in a portion of the image display device 60 rather than across its entire surface in a plan view, the overall thickness of the image display device 60 can be reduced.

[0034] As described above, the wiring board 10 comprises a transparent substrate 11, a mesh wiring section 20 arranged on the first surface 11a of the substrate 11, and a power supply section 40 electrically connected to the mesh wiring section 20. The power supply section 40 is electrically connected to the communication module 63 via a power supply line 85. Furthermore, a portion of the wiring board 10 is not positioned between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, but protrudes outward (towards the negative side in the Y direction) from between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. Specifically, the region of the wiring board 10 where the power supply section 40 is provided protrudes outward. This facilitates the electrical connection between the power supply section 40 and the communication module 63. On the other hand, the region of the wiring board 10 where the mesh wiring section 20 is provided is located between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. Details of the wiring board 10 and the power supply line 85 will be described later.

[0035] The second transparent adhesive layer 96 is an adhesive layer that directly or indirectly adheres the display device 61 to the wiring substrate 10. This second transparent adhesive layer 96 is located on the second surface 11b side of the substrate 11. The second transparent adhesive layer 96, like the first transparent adhesive layer 95, has optical transparency and may be an OCA (Optical Clear Adhesive) layer. The material of the second transparent adhesive layer 96 may be an acrylic resin, a silicone resin, or a urethane resin, etc. In particular, the second transparent adhesive layer 96 may contain an acrylic resin. This substantially eliminates the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, and more reliably suppresses the reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0036] The second transparent adhesive layer 96 may have a transmittance of 85% or more for visible light (light with a wavelength of 400 nm to 700 nm), and preferably 90% or more. There is no particular upper limit to the transmittance of visible light of the second transparent adhesive layer 96, but it may be, for example, 100% or less. By setting the transmittance of visible light of the second transparent adhesive layer 96 within the above range, the transparency of the laminate 70 for the image display device is increased, making the display device 61 of the image display device 60 easier to see.

[0037] In such an image display device 60, 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 preferably 0.05 or less. Furthermore, the difference between the refractive index of the substrate 11 and the refractive index of the second transparent adhesive layer 96 is 0.1 or less, and preferably 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 is preferably 0.1 or less, and more preferably 0.05 or less. For example, if the material of the first transparent adhesive layer 95 and the material of the second transparent adhesive layer 96 are acrylic resins with a refractive index of 1.49, the refractive index of the substrate 11 is set to 1.39 or more and 1.59 or less. Examples of such materials include fluororesins, silicone resins, polyolefin resins, polyester resins, acrylic resins, polycarbonate resins, polyimide resins, cellulose resins, and the like.

[0038] In this way, by keeping the difference between the refractive index of the substrate 11 and the refractive index of the first transparent adhesive layer 95 to 0.1 or less, the reflection of visible light at the interface B1 between the substrate 11 and the first transparent adhesive layer 95 is suppressed, making the substrate 11 difficult to see with the naked eye. Furthermore, by keeping the difference between the refractive index of the substrate 11 and the refractive index of the second transparent adhesive layer 96 to 0.1 or less, the reflection of visible light at the interface B2 between the substrate 11 and the second transparent adhesive layer 96 is suppressed, making the substrate 11 difficult to see with the naked eye. Moreover, by keeping the difference between the refractive index of the first transparent adhesive layer 95 and the refractive index of the second transparent adhesive layer 96 to 0.1 or less, the reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96 can be suppressed. Therefore, the first transparent adhesive layer 95 and the second transparent adhesive layer 96 can be made difficult to see with the naked eye.

[0039] In particular, it is preferable that the material of the first transparent adhesive layer 95 and the material of the second transparent adhesive layer 96 are the same material. This makes it possible to further reduce the difference in refractive index between the first transparent adhesive layer 95 and the second transparent adhesive layer 96, and to suppress the reflection of visible light at the interface B3 between the first transparent adhesive layer 95 and the second transparent adhesive layer 96.

[0040] Furthermore, in Figure 2, the thickness of at least one of the thicknesses T3 of the first transparent adhesive layer 95 and T4 of the second transparent adhesive layer 96 may be 1.5 times or more the thickness T1 of the substrate 11, preferably 2 times or more, and more preferably 2.5 times or more. By making the thickness T3 of the first transparent adhesive layer 95 or the thickness T4 of the second transparent adhesive layer 96 sufficiently thicker than 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. This makes it possible to suppress the occurrence of steps in the first transparent adhesive layer 95 or the second transparent adhesive layer 96 at the periphery of the substrate 11, making it difficult for observers to recognize the presence of the substrate 11.

[0041] The thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 are preferably 10 times or less the thickness T1 of the substrate 11, and more preferably 5 times or less. This prevents the thickness T3 of the first transparent adhesive layer 95 or the thickness T4 of the second transparent adhesive layer 96 from becoming too thick, thereby reducing the overall thickness of the image display device 60.

[0042] In Figure 2, the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 may 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 may each be 1.5 times or more the thickness T1 of the substrate 11, and preferably 2.0 times or more. That is, the sum of the thickness T3 of the first transparent adhesive layer 95 and the thickness T4 of the second transparent adhesive layer 96 (T3 + T4) is 3 times or more the thickness T1 of the substrate 11. In this way, by making the sum of the thicknesses T3 and T4 of the first transparent adhesive layer 95 and the second transparent adhesive layer 96 sufficiently thick compared 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, it is possible to suppress the occurrence of steps in the first transparent adhesive layer 95 or the second transparent adhesive layer 96 at the periphery of the substrate 11, making it difficult for observers to recognize the presence of the substrate 11.

[0043] 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 may be 5 times or less the thickness T1 of the substrate 11, and preferably 3 times or less. This prevents the thicknesses T3 and T4 of both the first transparent adhesive layer 95 and the second transparent adhesive layer 96 from becoming too thick, and allows the overall thickness of the image display device 60 to be reduced.

[0044] Specifically, the thickness T1 of the substrate 11 may be, for example, 2 μm or more, 10 μm or more, and preferably 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, and the first directional wiring 21 and second directional wiring 22 of the mesh wiring portion 20, described later, can be made less prone to deformation. Alternatively, the thickness T1 of the substrate 11 may be, for example, 200 μm or less, 50 μm or less, and preferably 25 μm or less. By setting the thickness T1 of the substrate 11 to 200 μm or less, the occurrence of steps between 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 observers to recognize the presence of the substrate 11. Furthermore, by setting the thickness T1 of the substrate 11 to 50 μm or less, the occurrence of steps between 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 observers to recognize the presence of the substrate 11.

[0045] The thickness T3 of the first transparent adhesive layer 95 may be, for example, 15 μm or more, and preferably 20 μm or more. The thickness T3 of the first transparent adhesive layer 95 may be, for example, 500 μm or less, preferably 300 μm or less, and more preferably 250 μm or less. The thickness T4 of the second transparent adhesive layer 96 may be, for example, 15 μm or more, and preferably 20 μm or more. The thickness T4 of the second transparent adhesive layer 96 may be, for example, 500 μm or less, preferably 300 μm or less, and more preferably 250 μm or less.

[0046] Referring again to Figure 2, the cover glass 75 is positioned directly or indirectly on the first transparent adhesive layer 95. The cover glass 75 is located on the positive Z-direction side of the first transparent adhesive layer 95. This cover glass 75 is a light-transmitting glass component. The cover glass 75 is plate-shaped, and its shape may be rectangular in plan view. The thickness of the cover glass 75 may be, for example, 200 μm or more and 1000 μm or less, and preferably 300 μm or more and 700 μm or less. The length of the cover glass 75 in the longitudinal direction (Y direction) may be, for example, 20 mm or more and 500 mm or less, preferably 100 mm or more and 200 mm or less. The length of the cover glass 75 in the short direction (X direction) may be 20 mm or more and 500 mm or less, preferably 50 mm or more and 100 mm or less. A decorative layer 74 is provided between this cover glass 75 and the first transparent adhesive layer 95.

[0047] The decorative layer 74 is positioned on the first transparent adhesive layer 95, at least in part. The decorative layer 74 may also be a decorative film. The decorative layer 74 has, for example, an opening in all or part of the portion that overlaps with the display area of ​​the display device 61 as viewed from the observer's side, thereby shielding the portion other than the display area from light. That is, the decorative layer 74 is positioned to cover the edge of the display device 61 as viewed from the observer's side.

[0048] As shown in Figure 1, the image display device 60 has a roughly rectangular shape in plan view, with its longitudinal direction parallel to the Y direction and its transverse direction parallel to the X direction. The length L4 of the longitudinal direction (Y direction) of the image display device 60 can be selected within the range of, for example, 20 mm to 500 mm, preferably 100 mm to 200 mm. The length L5 of the transverse direction (X direction) of the image display device 60 can be selected within the range of, for example, 20 mm to 500 mm, preferably 50 mm to 100 mm. The planar shape of the image display device 60 may also be a rectangle with rounded corners.

[0049] Next, the configuration of the wiring board will be described with reference to Figures 3 to 6. Figures 3 to 6 are diagrams showing the wiring board according to this embodiment.

[0050] The wiring board 10 according to this embodiment is a substrate used in the image display device 60 (see Figures 1 and 2) described above. The wiring board 10 is located on the light-emitting surface 64 side of the display device 61 and can be placed between the first transparent adhesive layer 95 and the second transparent adhesive layer 96. As shown in Figure 3, such a wiring board 10 has, as described above, a transparent substrate 11, a plurality of mesh wiring sections 20 arranged on the substrate 11, and a power supply section 40. The power supply section 40 is electrically connected to the mesh wiring sections 20.

[0051] The substrate 11 has a roughly rectangular shape in plan view. The substrate 11 is transparent and roughly flat, and its thickness is roughly uniform throughout. The length L1 of the substrate 11 in the longitudinal direction (Y direction) of the image display device 60 (see Figures 1 and 3) can be selected within a range of, for example, 10 mm to 200 mm. The length L2 of the substrate 11 in the short direction (X direction) of the image display device 60 (see Figure 1) can be selected within a range of, for example, 3 mm to 100 mm. The planar shape of the substrate 11 may be a rectangle with rounded corners.

[0052] The substrate 11 material may be any material having transparency in the visible light region and electrical insulation properties. Preferably, the substrate 11 material is an organic insulating material such as polyester resin, acrylic resin, polycarbonate resin, polyimide resin, polyolefin resin, cellulose resin, or fluororesin material. Polyester resin may be polyethylene terephthalate, etc. Acrylic resin may be polymethyl methacrylate, etc. Polyolefin resin may be cycloolefin polymer, etc. Cellulose resin may be triacetylcellulose, etc. Fluororesin material may be PTFE or PFA, etc. For example, the substrate 11 material may be an organic insulating material such as cycloolefin polymer (e.g., ZF-16 manufactured by Nippon Zeon Co., Ltd.) or polynorbornene polymer (manufactured by Sumitomo Bakelite Co., Ltd.). Furthermore, glass or ceramics may be appropriately selected as the substrate 11 material depending on the application. Although the illustration shows a substrate 11 composed of a single layer, it is not limited to this, and may have a structure in which multiple substrates or layers are laminated. Furthermore, the substrate 11 may be a film-like material or a plate-like material.

[0053] The dielectric loss tangent of the substrate 11 is preferably 0.002 or less. By having the dielectric loss tangent of the substrate 11 within the above range, the loss of gain (decrease in sensitivity) associated with the transmission and reception of electromagnetic waves can be reduced, especially when the electromagnetic waves (e.g., millimeter waves) transmitted and received by the mesh wiring section 20 are of high frequency.

[0054] The relative permittivity of the substrate 11 is preferably between 2 and 10. Having a relative permittivity of 2 or higher allows for a wider range of material choices for the substrate 11. Furthermore, having a relative permittivity of 10 or lower reduces the gain loss associated with electromagnetic wave transmission and reception. That is, when the relative permittivity of the substrate 11 is high, the influence of the substrate 11's thickness on electromagnetic wave propagation increases. Also, if electromagnetic wave propagation is negatively affected, the dielectric loss tangent of the substrate 11 increases, potentially leading to a greater gain loss associated with electromagnetic wave transmission and reception. In contrast, having a relative permittivity of 10 or lower reduces the influence of the substrate 11's thickness on electromagnetic wave propagation. Therefore, the gain loss associated with electromagnetic wave transmission and reception can be reduced. In particular, when the electromagnetic waves (e.g., millimeter waves) transmitted and received by the mesh wiring section 20 are high-frequency, the gain loss associated with electromagnetic wave transmission and reception can be reduced.

[0055] The dielectric loss tangent and relative permittivity of the substrate 11 can be measured in accordance with IEC 62562. Specifically, first, a test specimen is prepared by cutting out a portion of the substrate 11 where the mesh wiring section 20 is not formed. The dimensions of the test specimen shall be a width of 10 mm to 20 mm and a length of 50 mm to 100 mm. Next, the dielectric loss tangent or relative permittivity is measured in accordance with IEC 62562.

[0056] 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 to 700 nm) is 85% or more. The substrate 11 may have a visible light transmittance of 85% or more, but it is preferably 90% or more. There is no particular upper limit to the visible light transmittance of the substrate 11, but it may be, for example, 100% or less. By setting the visible light transmittance of the substrate 11 within the above range, the transparency of the wiring board 10 is increased, making the display device 61 of the image display device 60 easier to see.

[0057] In this embodiment, the mesh wiring section 20 consists of an antenna pattern that functions as an antenna. This mesh wiring section 20 may also be configured as an array antenna. When the mesh wiring section 20 is configured as an array antenna in this way, the performance of the millimeter-wave antenna for transmitting and receiving highly directional millimeter waves can be improved. An array antenna is an antenna in which a plurality of antenna elements (radiating elements) are arranged regularly, and in which the amplitude and phase of the excitation of the elements can be controlled independently.

[0058] As shown in Figure 3, multiple mesh wiring sections 20 are formed on the substrate 11. It is preferable that four or more mesh wiring sections 20 are provided. In the illustrated example, four mesh wiring sections 20 are formed on the substrate 11 (see Figure 1). Also, as shown in Figure 3, the mesh wiring sections 20 may not be present across the entire surface of the substrate 11, but only in a portion of the substrate 11. Each mesh wiring section 20 may have the same shape as the others. In this case, each mesh wiring section 20 has a length (Y-direction distance) L of the tip portion 20b, which will be described later. a Error and width (distance in the X direction) W a It is preferable that the errors are within 10% each. This effectively improves the performance of the millimeter-wave antenna.

[0059] The mesh wiring section 20 has a base end portion (transmission section) 20a on the power supply section 40 side and a tip end portion (transmitting / receiving section) 20b connected to the base end portion 20a. The base end portion 20a is connected to the power supply section 40. In this case, the base end portion (transmission section) 20a may constitute a microstrip line or a coplanar line. The shape of the base end portion 20a and the shape of the tip end portion 20b are both approximately rectangular in plan view. In this case, the length (Y-direction distance) of the tip end portion 20b is approximately the same as the length (Y-direction distance) of the base end portion 20a, and the width (X-direction distance) of the tip end portion 20b is wider than the width (X-direction distance) of the base end portion 20a.

[0060] The tip-side portion 20b of this mesh wiring portion 20 corresponds to a predetermined frequency band. That is, the tip-side portion 20b has a length (Y-direction distance) L a that corresponds to a specific frequency band. Note that the lower the frequency band to which it corresponds, the longer the length L a of the tip-side portion 20b. The mesh wiring portion 20 may correspond to any of an antenna for millimeter waves, an antenna for telephones, an antenna for WiFi, an antenna for 3G, an antenna for 4G, an antenna for 5G, an antenna for LTE, an antenna for Bluetooth (registered trademark), an antenna for NFC, etc. Note that the lengths of the plurality of tip-side portions 20b may be different from each other and each may correspond to a different frequency band. Alternatively, when the wiring substrate 10 does not have a radio wave transmission / reception function, each mesh wiring portion 20 may perform functions such as, for example, a hovering function, fingerprint authentication, a heater, noise cut (shield), etc. Note that the hovering function refers to a function that enables operation even when the user does not directly touch the display.

[0061] The longitudinal direction of the tip-side portion 20b is parallel to the X direction, and the short-side direction thereof is parallel to the Y direction. The length L a in the Y direction of the tip-side portion 20b can be selected, for example, in the range of 1 mm or more and 100 mm or less. The width W a in the X direction of the tip-side portion 20b can be selected, for example, in the range of 1 mm or more and 100 mm or less. In particular, when the mesh wiring portion 20 is an antenna for millimeter waves, the length L a of the tip-side portion 20b can be selected in the range of 1 mm or more, more preferably 1.5 mm or more. When the mesh wiring portion 20 is an antenna for millimeter waves, the length L a of the tip-side portion 20b can be selected in the range of 10 mm or less, more preferably 5 mm or less.

[0062] The distance between the mesh wiring portions 20 is preferably 1 mm or more and 5 mm or less. That is, the distance D 20b (see FIG. 3) between the tip-side portions 20b is preferably 1 mm or more and 5 mm or less. The distance D 20bThe fact that the distance between the tip portions 20b is 1 mm or more suppresses unintended interference of electromagnetic waves between antenna elements. 20b By keeping the distance between the mesh wiring sections 20 to 5 mm or less, the overall size of the array antenna formed by the mesh wiring section 20 can be reduced. For example, if the mesh wiring section 20 is a 28 GHz millimeter-wave antenna, the distance between the tip portions 20b is D 20b It may be 3.5 mm. Also, if the mesh wiring section 20 is a 60 GHz millimeter wave antenna, the distance D between the tip portions 20b is... 20b It may be 1.6 mm.

[0063] As shown in Figure 4, each mesh wiring section 20 has a pattern shape in which 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 section 20 has a pattern shape composed of a portion extending in a first direction (for example, the Y direction) (first direction wiring 21, described later) and a portion extending in a second direction (for example, the X direction) (second direction wiring 22, described later).

[0064] The mesh wiring section 20 has multiple wirings. Specifically, the mesh wiring section 20 has multiple first-directional wirings 21 and multiple second-directional wirings 22 that connect the multiple first-directional wirings 21. The multiple first-directional wirings 21 and the multiple second-directional wirings 22 together form a grid-like or mesh-like shape. Each first-directional wiring 21 extends in the longitudinal direction (Y direction) of the mesh wiring section 20. Each second-directional wiring extends linearly in the width direction (X direction) of the mesh wiring section 20. Note that the first-directional wirings 21 and the second-directional wirings 22 may extend in directions that are not parallel to either the X direction or the Y direction.

[0065] In the mesh wiring section 20, multiple openings 23 are formed by being surrounded by adjacent first-directional wiring 21 and adjacent second-directional wiring 22. The planar shape of each opening 23 is approximately square in plan view. A transparent substrate 11 is exposed through each opening 23. This enhances the overall transparency of the wiring board 10.

[0066] In the mesh wiring section 20, multiple openings 23 are formed by being surrounded by adjacent first-directional wiring 21 and adjacent second-directional wiring 22. Furthermore, the first-directional wiring 21 and second-directional wiring 22 are arranged at equal intervals from each other. That is, the multiple first-directional wiring 21 are arranged at equal intervals from each other, and their pitch P1 can be, for example, in the range of 0.01 mm to 1 mm. Similarly, the multiple second-directional wiring 22 are arranged at equal intervals from each other, and their pitch P2 can be, for example, in the range of 0.01 mm to 1 mm. In this way, because the multiple first-directional wiring 21 and the multiple second-directional wiring 22 are arranged at equal intervals, there is no variation in the size of the openings 23 within the mesh wiring section 20, making the mesh wiring section 20 difficult to see with the naked eye. In addition, the pitch P1 of the first-directional wiring 21 is equal to the pitch P2 of the second-directional wiring 22. Therefore, each opening 23 is approximately square in plan view, and the transparent substrate 11 is exposed through each opening 23. By increasing the area of ​​each opening 23, the overall transparency of the wiring board 10 can be increased. The length L3 of one side of each opening 23 can be, for example, in the range of 0.01 mm to 1 mm. Although each first directional wiring 21 and each second directional wiring 22 are orthogonal to each other, they are not limited to this and may intersect at acute or obtuse angles. Furthermore, while it is preferable for the shape and size of the openings 23 to be the same across the entire surface, they do not have to be uniform across the entire surface, for example, by varying them in different locations.

[0067] As shown in Figure 5, each first-direction wiring 21 has a shape in which the cross section perpendicular to its longitudinal direction (cross section in the X direction) is approximately rectangular or approximately square. In this case, the cross-sectional shape of the first-direction wiring 21 is approximately uniform along the longitudinal direction (Y direction) of the first-direction wiring 21. As shown in Figure 6, each second-direction wiring 22 has a cross section perpendicular to its longitudinal direction (cross section in the Y direction) that is approximately rectangular or approximately square, and has approximately the same shape as the cross-sectional shape (cross section in the X direction) 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 longitudinal 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 shape of the first direction wiring 21 and the cross-sectional shape of the second direction wiring 22 may be a roughly trapezoidal shape where the front side (positive Z-direction side) is narrower than the back side (negative Z-direction side), or a shape in which the sides located on both sides in the longitudinal direction are curved.

[0068] In this embodiment, the line width W1 of the first directional wiring 21 (see Figure 5) and the line width W2 of the second directional wiring 22 (see Figure 6) are not particularly limited and can be appropriately selected according to the application. Here, the line width W1 of the first directional wiring 21 is the width (distance in the X direction) in a cross section perpendicular to its longitudinal direction, and the line width W2 of the second directional wiring 22 is the width (distance in the Y direction) in a cross section perpendicular to its longitudinal direction. For example, the line width W1 of the first directional wiring 21 can be selected in the range of 0.1 μm to 5.0 μm, and is preferably 0.2 μm to 2.0 μm. Also, the line width W2 of the second directional wiring 22 can be selected in the range of 0.1 μm to 5.0 μm, and is preferably 0.2 μm to 2.0 μm.

[0069] 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) are not particularly limited and can be appropriately 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. The height H1 of the first direction wiring 21 and the height H2 of the second direction wiring 22 can each be selected in a range of, for example, 0.1 μm or more, and preferably 0.2 μm or more. The height H1 of the first direction wiring 21 and the height H2 of the second direction wiring 22 can each be selected in a range of, for example, 5.0 μm or less, and preferably 2.0 μm or less.

[0070] The material of the first directional wiring 21 and the second directional wiring 22 may be any conductive metallic material. In this embodiment, the material of the first directional wiring 21 and the second directional wiring 22 is copper, but is not limited to this. The material of the first directional wiring 21 and the second directional wiring 22 may be, for example, a metallic material such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals. Furthermore, the first directional wiring 21 and the second directional wiring 22 may be a plated layer formed by an electroplating method.

[0071] The overall aperture ratio At of the mesh wiring section 20 may be, for example, in the range of 87% or more and less than 100%. By setting the overall aperture ratio At of the mesh wiring section 20 within this range, the conductivity and transparency of the wiring board 10 can be ensured. Preferably, the overall aperture ratio At of the mesh wiring section 20 is 95% or more and less than 100%. This ensures the conductivity of the wiring board 10 while also increasing its transparency. The aperture ratio refers to the ratio (%) of the area of ​​the aperture region to the unit area of ​​a predetermined region (for example, the entire area of ​​the mesh wiring section 20). The aperture region refers to the area where there are no metal parts such as the first direction wiring 21 and the second direction wiring 22, and the substrate 11 is exposed.

[0072] Although not shown in the figures, a protective layer may be formed on the first surface 11a of the substrate 11 so as to cover the mesh wiring portion 20. The protective layer protects the mesh wiring portion 20 and is formed so as to cover at least the mesh wiring portion 20 of the substrate 11. As the material for the protective layer, a colorless, transparent insulating resin such as polymethyl (meth)acrylate, polyethyl (meth)acrylate, acrylic resins and their modified resins and copolymers, polyester, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinyl butyral, polyvinyl resins and their copolymers, polyurethane, epoxy resin, polyamide, or chlorinated polyolefin can be used.

[0073] Referring again to Figure 3, the power supply unit 40 is electrically connected to the mesh wiring unit 20. This power supply unit 40 consists of a roughly rectangular conductive thin plate-like member. The longitudinal direction of the power supply unit 40 is parallel to the X direction, and the short direction of the power supply unit 40 is parallel to the Y direction.

[0074] Furthermore, the power supply unit 40 is located at the longitudinal end (the negative Y-direction end) of the substrate 11. The material of the power supply unit 40 can be, for example, a metallic material such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals.

[0075] The power supply unit 40 is electrically connected to the communication module 63 of the image display device 60 (see Figures 1 and 2) via a power supply line 85 when the wiring board 10 is incorporated into the image display device 60. The power supply unit 40 is provided on the first surface 11a of the board 11, but is not limited to this, and part or all of the power supply unit 40 may be located outside the periphery of the board 11. Furthermore, by forming the power supply unit 40 flexibly, it may be configured to wrap around to the side or back of the image display device 60. In this case, the power supply unit 40 may be electrically connected to the communication module 63 on the side or back of the image display device 60.

[0076] The power supply section 40 is electrically connected to the mesh wiring section 20 on the positive side in the Y direction. In this case, the power supply section 40 is formed integrally with the mesh wiring section 20. The thickness T5 of the power supply section 40 (distance in the Z direction, see Figure 6) can be the same as 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), and can be selected in a range of, for example, 0.1 μm to 5.0 μm. In addition, an oxide film (first oxide film) 40a is formed on the surface of the power supply section 40.

[0077] Next, the module configuration will be described with reference to Figure 7. Figure 7 is a diagram showing the module according to this embodiment.

[0078] As shown in Figure 7, module 80A comprises the wiring board 10 described above and a power supply line 85 electrically connected to the power supply unit 40 via an anisotropic conductive film 85c. As described above, when module 80A is incorporated into the image display device 60 having a display device 61, the power supply unit 40 of the wiring board 10 is electrically connected to the communication module 63 of the image display device 60 via the power supply line 85.

[0079] The power supply line 85 is crimped to the wiring board 10 via an anisotropic conductive film (ACF) 85c. The anisotropic conductive film 85c contains a resin material such as acrylic resin or epoxy resin and a plurality of conductive particles 85d. In the illustrated example, the anisotropic conductive film 85c covers a portion of the power supply section 40. This helps to suppress corrosion of the power supply section 40.

[0080] The anisotropic conductive film 85c is positioned to face the power supply unit 40. A portion of each conductive particle 85d is in contact with the power supply unit 40. This electrically connects the power supply line 85 to the power supply unit 40. Note that a portion of the anisotropic conductive film 85c may dissolve around the power supply line 85 when the power supply line 85 is crimped to the wiring board 10.

[0081] The thickness T7 of the anisotropic conductive film 85c (see Figure 7) may be between 3 μm and 20 μm. A thickness T7 of 3 μm or more improves the adhesion between the power supply unit 40 and the power supply line 85. Furthermore, a thickness T7 of 20 μm or less reduces the thickness of the image display device 60.

[0082] The average particle diameter of the conductive particles 85d is between 3 μm and 20 μm. Having an average particle diameter of 3 μm or more allows the conductive particles 85d to easily come into contact with the power supply unit 40 and the metal wiring section 85b of the power supply line 85, as described later. This suppresses a decrease in electrical connectivity. Furthermore, having an average particle diameter of 20 μm or less prevents the thickness T7 of the anisotropic conductive film 85c from becoming excessively thick, allowing the overall thickness of the module 80A and the image display device 60 to be reduced.

[0083] When measuring the average particle diameter of conductive particles 85d, first, the power supply line 85 is peeled off from the power supply unit 40 to expose multiple conductive particles 85d from the resin material of the anisotropic conductive film 85c. Next, the exposed multiple conductive particles 85d are photographed using a scanning electron microscope (SEM). Then, the particle diameter of the multiple conductive particles 85d is measured from the obtained image. If the shape of the conductive particles 85d is irregular, the diameter is measured at multiple points on each conductive particle 85d and the average value is calculated. The average value of the measured values ​​of multiple conductive particles 85d is then taken as the average particle diameter of the conductive particles 85d. The number of conductive particles 85d to be measured is between 10 and 100. If the number of conductive particles 85d that can be measured on one power supply line 85 is 9 or less, the average particle diameter of the conductive particles 85d is calculated using the particle diameters of the conductive particles 85d on other power supply lines 85. Furthermore, if the conductive particles 85d are not exposed from the resin material of the anisotropic conductive film 85c, the shape of the conductive particles 85d within the resin material of the anisotropic conductive film 85c is imaged using a scanning electron microscope.

[0084] Furthermore, among a plurality of conductive particles 85d whose particle diameters have been measured, it is preferable that the value obtained by subtracting the minimum particle diameter from the maximum particle diameter for the remaining 60% of conductive particles 85d, after excluding 20% ​​of the conductive particles 85d with the largest particle diameters and 20% of the conductive particles 85d with the smallest particle diameters, is 60% or less of the average particle diameter. For example, if there are 100 conductive particles 85d whose particle diameters have been measured, it is preferable that the value obtained by subtracting the minimum particle diameter from the maximum particle diameter for the remaining 60 conductive particles 85d, after excluding 20 conductive particles 85d with the largest particle diameters and 20 conductive particles 85d with the smallest particle diameter, is 60% or less of the average particle diameter. In other words, if there are 100 conductive particles 85d whose particle diameters have been measured, it is preferable that the value obtained by subtracting the 80th particle diameter from the 21st particle diameter with the largest particle diameter is 60% or less of the average particle diameter. This reduces variations in the density of conductive particles 85d within the resin material of the anisotropic conductive film 85c. As a result, the antenna characteristics of the wiring board 10 can be stabilized.

[0085] The conductive particles 85d penetrate the oxide film 40a of the power supply unit 40. This effectively suppresses a decrease in electrical connectivity between the power supply line 85 and the power supply unit 40.

[0086] Furthermore, the conductive particles 85d penetrate the oxide film 85e of the power supply line 85, which will be described later. Even in this case, the decrease in electrical connectivity with the power supply line 85 can be effectively suppressed.

[0087] The power supply line 85 may be, for example, a flexible printed circuit board. The power supply line 85 has a base material 85a and a metal wiring section 85b laminated on the base material 85a. The base material 85a may contain, for example, a resin material such as polyimide or a liquid crystal polymer. The metal wiring section 85b may contain, for example, copper. The metal wiring section 85b is positioned to face the power supply section 40. An oxide film (second oxide film) 85e is formed on the surface of the metal wiring section 85b. This metal wiring section 85b is electrically connected to the power supply section 40 via conductive particles 85d.

[0088] Here, as shown in Figure 2, the power supply section 40 of the wiring board 10 and the power supply line 85 are joined to each other via a joint section 88. The length L7 of the joint section 88 is preferably 0.3 mm or more and 20 mm or less. By having a joint section 88 length L7 of 0.3 mm or more, the contact between the power supply section 40 and the power supply line 85 can be improved. Also, by having a joint section 88 length L7 of 20 mm or less, it is possible to prevent the power supply line 85 from extending into the display area of ​​the display device 61, thereby increasing the display area of ​​the display device 61. Furthermore, by having a joint section 88 length L7 of 20 mm or less, it is possible to prevent the power supply line 85 from getting too close to the housing 62, thereby preventing a large load from being placed on the power supply line 85 due to bending of the power supply line 85. As a result, power loss in the power supply line 85 can be reduced.

[0089] [Manufacturing Method for Wiring Board, Manufacturing Method for Module, and Manufacturing Method for Laminate for Image Display Device] Next, with reference to Figures 8(a)-(f), 9(a)-(c), and 10(a)-(c), the manufacturing method for the wiring board 10, the manufacturing method for the module 80A, and the manufacturing method for the laminate for image display device 70 according to this embodiment will be described. Figures 8(a)-(f) are cross-sectional views showing the manufacturing method for the wiring board 10 according to this embodiment. Figure 9(a)-(c) are cross-sectional views showing the manufacturing method for the module 80A according to this embodiment. Figure 10(a)-(c) are cross-sectional views showing the manufacturing method for the laminate for image display device 70 according to this embodiment.

[0090] First, the method for manufacturing a wiring board according to this embodiment will be described with reference to Figures 8(a)-(f).

[0091] First, as shown in Figure 8(a), a substrate 11 is prepared, which includes a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The substrate 11 is transparent.

[0092] Next, a mesh wiring section 20 and a power supply section 40 electrically connected to the mesh wiring section 20 are formed on the first surface 11a of the substrate 11.

[0093] In this case, first, as shown in Figure 8(b), a metal foil 51 is laminated over substantially the entire surface 11a of the substrate 11. In this embodiment, the thickness of the metal foil 51 may be 0.1 μm or more and 5.0 μm or less. In this embodiment, the metal foil 51 may contain copper.

[0094] Next, as shown in Figure 8(c), a photocurable insulating resist 52 is supplied to substantially the entire surface of the metal foil 51. Examples of photocurable insulating resists 52 include organic resins such as acrylic resins and epoxy resins.

[0095] Next, as shown in Figure 8(d), the insulating layer 54 is formed by photolithography. In this case, the photocurable insulating resist 52 is patterned by photolithography to form the insulating layer 54 (resist pattern). At this time, the insulating layer 54 is formed so that the metal foil 51 corresponding to the first directional wiring 21 and the second directional wiring 22 is exposed.

[0096] Next, as shown in Figure 8(e), the metal foil 51 located on the first surface 11a of the substrate 11, in the portion not covered by the insulating layer 54, is removed. In this process, the metal foil 51 is etched so that the first surface 11a of the substrate 11 is exposed by performing a wet treatment using ferric chloride, cupric chloride, strong acids such as sulfuric acid and hydrochloric acid, persulfates, hydrogen peroxide, aqueous solutions thereof, or combinations thereof.

[0097] Next, as shown in Figure 8(f), the insulating layer 54 is removed. In this case, the insulating layer 54 on the metal foil 51 is removed by wet treatment using a permanganate solution, N-methyl-2-pyrrolidone, an acid or alkaline solution, or by dry treatment using oxygen plasma.

[0098] In this way, a wiring board 10 is obtained having a substrate 11 and a mesh wiring section 20 provided on the first surface 11a of the substrate 11. In this case, the mesh wiring section 20 includes first-direction wiring 21 and second-direction wiring 22. At this time, a power supply section 40 may be formed by a part of the metal foil. Alternatively, a flat plate-shaped power supply section 40 may be prepared separately and electrically connected to the mesh wiring section 20.

[0099] Next, the method for manufacturing a module according to this embodiment will be described with reference to Figures 9(a)-(c).

[0100] First, prepare the wiring board 10 as shown in Figure 9(a). In this case, the wiring board 10 is manufactured, for example, by the method shown in Figures 8(a)-(f).

[0101] Next, the power supply line 85 is electrically connected to the power supply unit 40 via an anisotropic conductive film 85c containing multiple conductive particles 85d. First, as shown in Figure 9(b), the anisotropic conductive film 85c and the power supply line 85 are placed on the wiring board 10. At this time, the anisotropic conductive film 85c is positioned to face the power supply unit 40.

[0102] Next, as shown in Figure 9(c), the power supply line 85 is crimped to the wiring board 10. At this time, pressure and heat are applied to the power supply line 85 to crimp it to the wiring board 10. Then, the conductive particles 85d come into contact with the power supply unit 40. At this time, the conductive particles 85d penetrate the oxide film 40a. Also, the conductive particles 85d come into contact with the metal wiring portion 85b of the power supply line 85. At this time, the conductive particles 85d penetrate the oxide film 85e. In this way, the power supply unit 40 and the power supply line 85 are joined to each other via the joint portion 88, and the power supply line 85 is electrically connected to the power supply unit 40. When crimping the power supply line 85 to the wiring board 10, the power supply line 85 is crimped to the wiring board 10 such that the anisotropic conductive film 85c covers at least a part of the power supply unit 40. At this time, a portion of the anisotropic conductive film 85c may dissolve into the area around the power supply line 85.

[0103] In this way, a module 80A is obtained that includes a wiring board 10 and a power supply line 85 electrically connected to a power supply unit 40 via an anisotropic conductive film 85c containing conductive particles 85d.

[0104] Next, with reference to Figures 10(a)-(c), a method for manufacturing the image display device 60 according to this embodiment will be described.

[0105] Next, the first transparent adhesive layer 95, the wiring board 10 of module 80A, and the second transparent adhesive layer 96 are laminated together. First, as shown in Figure 10(a), an OCA sheet 90 is prepared, which includes, for example, a release film 91 made of polyethylene terephthalate (PET) and an OCA layer 92 (first transparent adhesive layer 95 or second transparent adhesive layer 96) laminated on the release film 91. At this time, the OCA layer 92 may be a layer obtained by coating the release film 91 with a liquid curable adhesive layer composition containing a polymerizable compound and curing it using, for example, ultraviolet light (UV). This curable adhesive layer composition contains a polar group-containing monomer.

[0106] Next, as shown in Figure 10(b), the OCA layer 92 of the OCA sheet 90 is bonded to the wiring board 10. This sandwiches the wiring board 10 between the OCA layer 92.

[0107] Next, as shown in Figure 10(c), the release film 91 is peeled off from the OCA layer 92 of the OCA sheet 90 bonded to the wiring board 10, thereby obtaining the first transparent adhesive layer 95 (OCA layer 92), the wiring board 10, and the second transparent adhesive layer 96 (OCA layer 92) which are laminated together.

[0108] Subsequently, a decorative film as a decorative layer 74 and a cover glass 75 are laminated on the first transparent adhesive layer 95.

[0109] In this way, a laminate 70 for an image display device is obtained, comprising a first transparent adhesive layer 95, a second transparent adhesive layer 96, and a module 80A having a wiring board 10.

[0110] Subsequently, by stacking the display device 61 on the image display device laminate 70, an image display device 60 is obtained, comprising the image display device laminate 70 and the display device 61 stacked on the image display device laminate 70.

[0111] [Operation of this embodiment] Next, we will describe the operation of this embodiment, which has the above configuration.

[0112] As shown in Figures 1 and 2, the wiring board 10 is incorporated into an image display device 60 having a display device 61. At this time, the wiring board 10 is placed on the display device 61. The mesh wiring section 20 of the wiring board 10 is electrically connected to the communication module 63 of the image display device 60 via the power supply section 40 and the power supply line 85. In this way, radio waves of a predetermined frequency can be transmitted and received via the mesh wiring section 20, and communication can be performed using the image display device 60.

[0113] In this embodiment, the power supply line 85 is electrically connected to the power supply unit 40 via an anisotropic conductive film 85c containing a plurality of conductive particles 85d. The average particle diameter of the conductive particles 85d is 3 μm or more and 20 μm or less. By having an average particle diameter of 3 μm or more for the conductive particles 85d, the conductive particles 85d are more likely to come into contact with the power supply unit 40 and the metal wiring unit 85b. This suppresses a decrease in electrical connectivity. Furthermore, by having an average particle diameter of 20 μm or less for the conductive particles 85d, the thickness T7 of the anisotropic conductive film 85c does not become too thick, and the overall thickness of the module 80A and the image display device 60 can be reduced.

[0114] Furthermore, according to this embodiment, the wiring board 10 comprises a substrate 11 and a mesh wiring section 20 disposed on the substrate 11. The substrate 11 is transparent. Moreover, the mesh wiring section 20 has a conductive section as a part for forming an opaque conductive layer and a mesh-like pattern with a large number of openings. Thus, the transparency of the wiring board 10 is ensured. As a result, when the wiring board 10 is placed on the display device 61, the display device 61 can be seen through the openings 23 of the mesh wiring section 20, and the visibility of the display device 61 is not obstructed.

[0115] Furthermore, according to this embodiment, the conductive particles 85d penetrate the oxide film 40a of the power supply unit 40. This effectively suppresses a decrease in electrical connectivity between the power supply line 85 and the power supply unit 40.

[0116] Furthermore, according to this embodiment, the conductive particles 85d penetrate the oxide film 85e of the power supply line 85, which will be described later. Even in this case, the decrease in electrical connectivity with the power supply line 85 can be effectively suppressed.

[0117] Next, we will describe a modified example of a wiring board.

[0118] Figures 11 and 12 show a first modified example of the wiring board. The modified example shown in Figures 11 and 12 differs in that a dummy wiring section 30 is provided around the mesh wiring section 20, while the other configurations are substantially the same as those shown in Figures 1 to 10 described above. In Figures 11 and 12, the same reference numerals are used for parts that are the same as those shown in Figures 1 to 10, and detailed explanations are omitted.

[0119] In the wiring board 10 shown in Figure 11, a dummy wiring section 30 is provided around the mesh wiring section 20. Unlike the mesh wiring section 20, this dummy wiring section 30 does not function as an antenna in any substantial way.

[0120] As shown in Figure 12, the dummy wiring section 30 is composed of repeating dummy wiring 30a having a predetermined pattern shape. That is, the dummy wiring section 30 includes multiple dummy wiring 30a, and each dummy wiring 30a is electrically independent from the mesh wiring section 20 (first direction wiring 21 and second direction wiring 22). Furthermore, the multiple dummy wiring 30a are regularly arranged throughout the entire area of ​​the dummy wiring section 30. The multiple dummy wiring 30a are spaced apart from each other in the planar direction and are arranged to protrude from the substrate 11. That is, each dummy wiring 30a is electrically independent from the mesh wiring section 20, the power supply section 40, and other dummy wiring 30a. The shape of each dummy wiring 30a is approximately L-shaped in plan view.

[0121] In this case, the dummy wiring 30a has a shape in which a part of the pattern shape of the mesh wiring section 20 described above is missing. This makes it difficult to visually recognize the difference between the mesh wiring section 20 and the dummy wiring section 30, and makes the mesh wiring section 20 placed on the substrate 11 less visible. As shown in Figure 12, the dummy wiring 30a extends parallel to the first direction wiring 21 or the second direction wiring 22. Specifically, the dummy wiring 30a includes a first portion 31a that extends parallel to the first direction wiring 21 and a second portion 32a that extends parallel to the second direction wiring 22. In this way, because the dummy wiring 30a extends parallel to the first direction wiring 21 or the second direction wiring 22, the mesh wiring section 20 placed on the substrate 11 can be made even less visible. The aperture ratio of the dummy wiring section 30 may be the same as or different from the aperture ratio of the mesh wiring section 20, but it is preferable that it is close to the aperture ratio of the mesh wiring section 20.

[0122] As shown in this modified example, by providing a dummy wiring section 30 electrically independent from the mesh wiring section 20 around the mesh wiring section 20, the outer edge of the mesh wiring section 20 can be obscured. This makes the mesh wiring section 20 less visible on the surface of the image display device 60, making it difficult for users of the image display device 60 to recognize the mesh wiring section 20 with the naked eye.

[0123] Figures 13 and 14 show a second modified example of the wiring board. The modified example shown in Figures 13 and 14 differs in that multiple dummy wiring sections 30A and 30B with different opening ratios are provided around the mesh wiring section 20, while the other configurations are substantially the same as those shown in Figures 1 to 12 described above. In Figures 13 and 14, the same reference numerals are used for parts that are the same as those shown in Figures 1 to 12, and detailed explanations are omitted.

[0124] In the wiring board 10 shown in Figure 13, multiple (in this case, two) dummy wiring sections 30A and 30B (first dummy wiring section 30A and second dummy wiring section 30B) with different aperture ratios are provided around the mesh wiring section 20. Specifically, the first dummy wiring section 30A is arranged around the mesh wiring section 20, and the second dummy wiring section 30B is arranged around the first dummy wiring section 30A. Unlike the mesh wiring section 20, these dummy wiring sections 30A and 30B do not substantially function as antennas.

[0125] As shown in Figure 14, the first dummy wiring section 30A is composed of repeating dummy wiring 30a1 having a predetermined pattern shape. The second dummy wiring section 30B is composed of repeating dummy wiring 30a2 having a predetermined pattern shape. That is, the dummy wiring sections 30A and 30B each contain multiple dummy wirings 30a1 and 30a2, and each dummy wiring 30a1 and 30a2 is electrically independent from the mesh wiring section 20. Furthermore, the dummy wirings 30a1 and 30a2 are regularly arranged throughout the entire area of ​​the dummy wiring sections 30A and 30B, respectively. Each dummy wiring 30a1 and 30a2 is spaced apart from each other in the planar direction and is positioned protruding from the substrate 11. Each dummy wiring 30a1 and 30a2 is electrically independent from the mesh wiring section 20, the power supply section 40, and other dummy wirings 30a1 and 30a2. The shapes of each dummy wire 30a1 and 30a2 are roughly L-shaped when viewed from above.

[0126] In this case, the dummy wiring 30a1 and 30a2 have a shape in which a part of the pattern shape of the mesh wiring section 20 described above is missing. This makes it difficult to visually recognize the difference between the mesh wiring section 20 and the first dummy wiring section 30A, and the difference between the first dummy wiring section 30A and the second dummy wiring section 30B, and makes the mesh wiring section 20 placed on the substrate 11 less visible. As shown in Figure 14, the dummy wiring 30a1 and 30a2 extend parallel to the first direction wiring 21 or the second direction wiring 22. Specifically, the dummy wiring 30a1 includes a first portion 31a1 that extends parallel to the first direction wiring 21 and a second portion 32a1 that extends parallel to the second direction wiring 22. The 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.

[0127] Furthermore, the area of ​​each dummy wire 30a1 in the first dummy wiring section 30A is larger than the area of ​​each dummy wire 30a2 in the second dummy wiring section 30B. In this case, the line width of each dummy wire 30a1 is the same as the line width of each dummy wire 30a2, but this is not limited to this, and the line width of each dummy wire 30a1 may be thicker than the line width of each dummy wire 30a2. Furthermore, the other configurations of the dummy wires 30a1 and 30a2 are the same as the configuration of the dummy wire 30a in the third modified example, so a detailed explanation is omitted here.

[0128] In this modified example, it is preferable that the aperture ratio of the mesh wiring section 20 and the multiple dummy wiring sections 30A and 30B gradually increases from the mesh wiring section 20 toward the dummy wiring sections 30A and 30B that are further away from the mesh wiring section 20. In other words, it is preferable that the aperture ratio of each dummy wiring section gradually increases from those closer to the mesh wiring section 20 toward those further away. In this case, it is preferable that the aperture ratio of the first dummy wiring section 30A is greater than the aperture ratio of the mesh wiring section 20. It is also preferable that the aperture ratio of the second dummy wiring section 30B is greater than the aperture ratio of the first dummy wiring section 30A. This makes the outer edges of the mesh wiring section 20 and the dummy wiring sections 30A and 30B even more indistinct. As a result, the mesh wiring section 20 can be made even less visible on the surface of the image display device 60.

[0129] In this way, by arranging dummy wiring sections 30A and 30B that are electrically independent from the mesh wiring section 20, the outer edge of the mesh wiring section 20 can be made more indistinct. As a result, the mesh wiring section 20 can be made less visible on the surface of the image display device 60, making it difficult for users of the image display device 60 to recognize the mesh wiring section 20 with the naked eye. In addition, three or more dummy wiring sections with different aperture ratios may be provided around the mesh wiring section 20.

[0130] Figure 15 shows a third modified example of the wiring board. The modified example shown in Figure 15 differs in the planar shape of the mesh wiring section 20, but the other components are substantially the same as those shown in Figures 1 to 14 described above. In Figure 15, the same reference numerals are used for parts that are the same as those shown in Figures 1 to 14, and detailed explanations are omitted.

[0131] In Figure 15, the first directional wiring 21 and the second directional wiring 22 intersect at an angle (not perpendicular), and each opening 23 is formed in a rhombus shape in plan view. Neither the first directional wiring 21 nor the second directional wiring 22 are parallel to either the X or Y direction, but either one of the first directional wiring 21 or the second directional wiring 22 may be parallel to either the X or Y direction.

[0132] The multiple components disclosed in the above embodiments and each of their variations can be combined as needed. Alternatively, some components may be removed from all the components shown in the above embodiments and each of their variations.

Claims

1. A wiring board having a substrate including a first surface and a second surface located opposite the first surface, a mesh wiring section disposed on the first surface of the substrate, and a power supply section electrically connected to the mesh wiring section, The power supply unit is electrically connected to a power supply line via an anisotropic conductive film containing multiple conductive particles. The aforementioned wiring board has an electromagnetic wave transmission and reception function, The substrate is transparent, The aforementioned mesh wiring section is configured as an antenna. In the mesh wiring section, an opening is formed to expose the substrate. The aforementioned power supply unit does not have the aforementioned opening formed therein. A module in which the average particle diameter of the conductive particles is 3 μm or more and 20 μm or less.

2. The module according to claim 1, wherein, of the plurality of conductive particles, 20% of the conductive particles are excluded in order from the largest particle diameter, and 20% of the conductive particles are excluded in order from the smallest particle diameter, and in the remaining 60% of the conductive particles, the value obtained by subtracting the minimum value from the maximum value of the particle diameter is 60% or less of the average particle diameter.

3. The module according to claim 1, wherein the wiring board has millimeter-wave transmitting and receiving functions, and the mesh wiring section is configured as an array antenna.

4. The module according to claim 1, wherein the thickness of the anisotropic conductive film is 3 μm or more and 20 μm or less.

5. The module according to claim 1, wherein a first oxide film is formed on the surface of the power supply section, and the conductive particles penetrate the first oxide film.

6. The module according to claim 1, wherein the power supply line comprises a base material and a metal wiring portion laminated on the base material, a second oxide film is formed on the surface of the metal wiring portion, and the conductive particles penetrate the second oxide film.

7. The module according to claim 1, wherein the distance between the mesh wiring sections is 1 mm or more and 5 mm or less.

8. The module according to claim 1, wherein a dummy wiring section is provided around the mesh wiring section, electrically independent from the mesh wiring section.

9. The module according to claim 8, wherein a plurality of dummy wiring sections are provided, and the opening ratio of the mesh wiring section and the dummy wiring section increases in stages from the mesh wiring section toward the dummy wiring section further away from the mesh wiring section.

10. A module according to any one of claims 1 to 9, A first adhesive layer located on the first surface side of the substrate, The substrate comprises a second adhesive layer located on the second surface side, A laminate for an image display device, wherein a portion of the substrate is disposed in a portion of the region between the first adhesive layer and the second adhesive layer.

11. A laminate for an image display device according to claim 10, An image display device comprising a display device formed by stacking the aforementioned image display device laminates.

12. A method for manufacturing a module, A step of preparing a substrate including a first surface and a second surface located opposite the first surface, A step of manufacturing a wiring board by forming a mesh wiring section and a power supply section electrically connected to the mesh wiring section on the first surface of the substrate, The process includes the step of electrically connecting a power supply line to the power supply unit via an anisotropic conductive film containing multiple conductive particles, The aforementioned wiring board has an electromagnetic wave transmission and reception function, The substrate is transparent, The aforementioned mesh wiring section is configured as an antenna. In the mesh wiring section, an opening is formed to expose the substrate. The aforementioned power supply unit does not have the aforementioned opening formed therein. A method for manufacturing a module, wherein the average particle diameter of the conductive particles is 3 μm or more and 20 μm or less.

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