Conductive film and display device

Abstract

A conductive film provided with a base material and a conductive part provided on the main surface side of the base material, the conductive part having a main body part containing a first metal and a blackened layer covering at least the surface of the main body part on the opposite side from the base material, the blackened layer containing the first metal and a second metal different from the first metal, the blackening layer has a crystal structure with a space group of Pm-3m.

Description

Technical Field

[0001] The present disclosure relates to a conductive film and a display device. Background Art

[0002] A display device having a display portion such as a touch panel may include a conductive film having a conductive pattern in which conductive portions are formed in a mesh shape on the surface side of the display portion.

[0003] In such a conductive film, in order to suppress reflection of light from the conductive portion, the conductive pattern may include a conductive portion main body and a blackened layer provided on the conductive portion main body.

[0004] For example, the following patent document 1 discloses a conductive film, which includes a substrate and a conductive part composed of metal fine wires, and the above-mentioned conductive part is arranged on at least one main surface of the substrate, wherein the metal fine wires include a base layer and a conductive layer and a blackening layer covering the surface of the conductive layer arranged in sequence from the substrate side, and the line width of the metal fine wires is less than 2.0 μm, the base layer contains metal oxide or metal nitride as a main component, the blackening layer contains palladium, and the conductive layer contains copper as a main component.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2019 / 065782 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the conductive film described in Patent Document 1 has the following problems.

[0010] That is, although the conductive film described in Patent Document 1 suppresses reflection of light and improves invisibility, there is still room for improvement in terms of improving conductivity.

[0011] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a conductive film and a display device that can improve conductivity while suppressing reflection of light.

[0012] Technical solutions to solve problems

[0013] One aspect of the present disclosure provides a conductive film, which has a substrate and a conductive part arranged on the main surface side of the substrate, the conductive part has: a main body, which contains a first metal; and a blackening layer, which covers the surface of the main body on at least the side opposite to the substrate, the blackening layer contains the first metal and a second metal different from the first metal, and the blackening layer has a crystal structure with a space group of Pm-3m.

[0014] Effects of the Invention

[0015] The present disclosure can provide a conductive film and a display device that can improve conductivity while suppressing reflection of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a partial plan view showing one embodiment of the conductive film disclosed herein.

[0017] Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0018] Figure 3 This is a cross-sectional view showing the first structure obtained in the first step.

[0019] Figure 4 is a cross-sectional view showing the second structure obtained in the second step.

[0020] Figure 5 This is a cross-sectional view showing the third structure obtained in the third step.

[0021] Figure 6 It is a cross-sectional view showing the fifth structure obtained in the fifth step.

[0022] Figure 7 This is a partial cross-sectional view showing one embodiment of the display device of the present disclosure.

[0023] Figure 8 This is a partial cross-sectional view showing another embodiment of the conductive film disclosed herein. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present disclosure will be described in detail.

[0025] <<Conductive film>>

[0026] First, one embodiment of the conductive film of the present disclosure will be described with reference to the drawings. Figure 1 This is a partial plan view showing one embodiment of the conductive film disclosed herein. Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0027] Figure 1 and Figure 2 The conductive film 100 shown includes a substrate 10 , a mesh wiring 40 including linear conductive portions 20 provided on the principal surface 10S side of the substrate 10 , and a resin layer 30 .

[0028] The resin layer 30 is provided on the main surface 10S of the substrate 10 and has a groove 33 on the side opposite to the substrate 10 . The conductive portion 20 is filled in the groove 33 and fixed to the substrate 10 via the resin layer 30 .

[0029] The conductive part 20 sequentially comprises a main body 21 including a first metal and a black layer 22. The black layer 22 is disposed in the groove 33 and covers a first surface 21c of the main body 21 on the side opposite to the substrate 10. The black layer 22 comprises a first metal and a second metal different from the first metal, and has a crystal structure with a space group of Pm-3m.

[0030] According to the conductive film 100, in the conductive part 20 provided on the main surface 10S of the substrate 10, since the black layer 22 covers the first surface 21c of the surface of the main body 21, even when light is incident on the main surface 10S of the substrate 10, the reflection of the light is suppressed by the black layer 22. In addition, in a state where the main body 21 includes a first metal and the black layer 22 includes the first metal and a second metal different from the first metal, if the black layer 22 has a crystal structure of a space group of Pm-3m, the resistance value of the black layer 22 of the conductive part 20 is reduced, and therefore, the resistance value of the conductive part 20 is reduced as a whole. Therefore, the conductivity of the conductive film 100 can be improved. This is particularly effective when the high-frequency current flowing to the conductive part 20 mainly flows on the surface of the conductive part 20 due to the skin effect. This is because, when the high-frequency current mainly flows on the surface of the conductive part 20, the resistance value of the black layer 22 constituting a part of the surface of the conductive part 20 has a large influence on the conductivity of the conductive part 20.

[0031] The inventors of the present disclosure speculate as follows about the reason why the resistance value of the blackened layer 22 decreases when the blackened layer 22 has a crystal structure with a space group of Pm-3m.

[0032] That is, in the crystal structure of the space group Fm-3m, the atoms of the second metal exist randomly, and the regularity of the crystal structure becomes low. In contrast, in the crystal structure of the space group Pm-3m, the atoms of the second metal exist in a specific lattice (place), and the regularity of the crystal structure becomes high. Therefore, it is believed that in the blackened layer 22 including the crystal structure of the space group Pm-3m, the flow of electrons is not hindered when current flows, and a low resistance value can be obtained.

[0033] In addition, the conductive portion 20 is filled in the groove 33 of the resin layer 30 . Therefore, the conductive portion 20 is stably fixed to the base material 10 by the resin layer 30 , and the conductive portion 20 is not easily peeled off from the base material 10 .

[0034] Next, the base material 10 , the conductive portion 20 , and the resin layer 30 will be described in detail.

[0035] <Base material>

[0036] The substrate 10 is a member for fixing the conductive part 20. The substrate 10 may be a light-transmitting substrate. The light-transmitting substrate has, for example, a degree of light transmittance required when the conductive film 100 is included in a display device. Specifically, the total light transmittance of the substrate 10 may be 90 to 100%. Alternatively, the haze of the substrate 10 may also be 0 to 5%.

[0037] The substrate 10 may be, for example, a transparent resin film, and examples thereof include films of polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), cycloolefin polymer (COP), or polyimide (PI). The substrate 10 may also be a glass substrate.

[0038] The thickness of the substrate 10 may be 1 μm or more, 10 μm or more, or 20 μm or less, or 500 μm or less, 200 μm or less, or 100 μm or less.

[0039] <Conductive part>

[0040] The conductive part 20 includes a main body part 21 and a blackened layer 22. The conductive part 20 may further include a base layer 23 on the main body part 21 on the substrate 10 side.

[0041] The width of the conductive portion 20 is not particularly limited, but is preferably 4 μm or less, more preferably 2 μm or less, from the viewpoint of improving invisibility. However, from the viewpoint of reducing the resistance of the conductive portion 20, the width of the conductive portion 20 is preferably 0.5 μm or more, more preferably 0.8 μm or more.

[0042] Furthermore, the width of the conductive portion 20 specifically refers to the width in a direction perpendicular to the extending direction of the conductive portion 20 when the conductive portion 20 is viewed from the blackened layer 22 side.

[0043] In the mesh wiring 40, the spacing (pitch) between the opposing conductive parts 20 is not particularly limited, but is preferably 300 μm or less, more preferably 200 μm or less from the viewpoint of improving conductivity. From the viewpoint of improving invisibility, the pitch of the conductive part 20 may be, for example, 50 μm or more, or 80 μm or more.

[0044] (Main body)

[0045] The main body 21 includes a first metal. The first metal is not particularly limited, and examples of the first metal include copper (Cu), gold (Au), and silver (Ag).

[0046] The main body 21 may further contain non-metallic elements such as phosphorus within a range in which appropriate conductivity can be maintained.

[0047] The space group of the crystal structure contained in the main body 21 is not particularly limited, and may be Pm-3m or Fm-3m, but is preferably Fm-3m.

[0048] The mass content of the first metal in the main body 21 may be, for example, 50 mass % or more, 55 mass % or more, or 100 mass %.

[0049] The main body 21 may include crystal grains. The maximum size of the grain size (crystal grain diameter) is not particularly limited, but is preferably 30 nm or less, and more preferably 25 nm or less. The maximum size of the crystal grain diameter included in the main body 21 may be 5 nm or more, or 8 nm or more.

[0050] The “maximum size of crystal grains” in the present disclosure refers to the maximum size of crystal grains among 10 crystal grains included in a field of view when any region of a cross section in the thickness direction of the main body 21 is observed using a transmission electron microscope (TEM).

[0051] In addition, the size of a crystal grain refers to the distance between two points on a grain boundary of a crystal grain when the distance between the two points is the maximum.

[0052] The thickness of the main body 21 is appropriately set based on the resistance value required for the conductive part 20 and is not particularly limited. For example, it may be 1.0 μm or more, 1.5 μm or more, or 2.0 μm or more. The thickness of the main body 21 may be 6.0 μm or less, 5.0 μm or less, or 4.0 μm or less.

[0053] Preferably, the main body 21 of the conductive portion 20 and the resin layer 30 are in direct contact with each other without the blackened layer 22 interposed therebetween, over all or part of the interface between the main body 21 of the conductive portion 20 and the resin layer 30 .

[0054] In this case, even when a high-frequency current flowing to the conductive portion 20 flows on the surface of the conductive portion 20 due to the skin effect, the conductivity of the conductive portion 20 can be further improved because the proportion of the blackened layer 22 on the surface of the conductive portion 20 is reduced.

[0055] exist Figure 2 2 shows a state in which the main body 21 of the conductive portion 20 and the resin layer 30 are in direct contact with each other without the blackened layer 22 interposed therebetween over the entire interface between the main body 21 of the conductive portion 20 and the resin layer 30 .

[0056] Furthermore, at a part of the interface between the main body portion 21 of the conductive portion 20 and the resin layer 30 , the main body portion 21 and the resin layer 30 may be in contact with each other via the blackened layer 22 .

[0057] (Blackening layer)

[0058] The blackened layer 22 includes a first metal and a second metal different from the first metal.

[0059] As the first metal, the same metal as the first metal contained in the main body 21 is used.

[0060] The second metal may be any metal as long as it is different from the first metal, but preferably has a reflectance in the visible light region lower than that of the first metal. Examples of the second metal include palladium (Pd) and nickel (Ni).

[0061] In the blackened layer 22 , for example, the first metal may be Cu and the second metal may be Pd.

[0062] The mass content of the first metal in the black layer 22 is not particularly limited, and is preferably 50 mass % or more. In this case, there is a tendency to reduce the resistance value of the black layer 22. The mass content of the first metal in the black layer 22 may be 53 mass % or more, or 55 mass % or more. The mass content of the first metal in the black layer 22 may be 95 mass % or less, 90 mass % or less, or 85 mass % or less.

[0063] The mass content of the second metal in the black layer 22 may be 15 mass % or more, 20 mass % or more, or 25 mass % or more. The mass content of the second metal in the black layer 22 may be 50 mass % or less, 48 ​​mass % or less, or 45 mass % or less. The mass content of the second metal in the black layer 22 is preferably 43 mass % or less.

[0064] The mass content of the first metal in the blackening layer 22 may be greater than the mass content of the second metal in the blackening layer 22, or may be less than the mass content of the second metal, but preferably, the mass content of the first metal in the blackening layer 22 is greater than the mass content of the second metal in the blackening layer 22, that is, the ratio R2 of the mass content of the first metal in the blackening layer 22 to the mass content of the second metal in the blackening layer 22 is greater than 1.

[0065] In this case, the space group of the crystal structure included in the blackened layer 22 is likely to be Pm-3m, and the resistance value of the blackened layer 22 is effectively reduced, thereby effectively reducing the resistance value of the conductive portion 20 as a whole. Therefore, the conductivity of the conductive film 100 can be effectively improved.

[0066] The ratio R2 is not particularly limited as long as it is greater than 1, but is preferably 1.2 or greater, and more preferably 1.4 or greater. However, the ratio R2 is preferably 2.1 or less, and more preferably 2.0 or less.

[0067] The crystal system contained in the black layer 22 may be the same as or different from the crystal system of the first metal contained in the main body 21, but preferably the same. The lattice of the crystal system contained in the black layer 22 may be the same as or different from the lattice of the first metal, but preferably the same. In this case, the resistance value of the black layer 22 can be effectively reduced. The crystal system varies depending on the type of the first metal, and examples thereof include cubic crystals, tetragonal crystals, and the like.

[0068] For example, when the first metal is Cu, the crystal system of Cu is cubic and the crystal lattice is face-centered cubic (fcc). Therefore, it is preferable that the crystal system contained in the blackened layer 22 is cubic and the crystal lattice is face-centered cubic.

[0069] The compound constituting the crystal structure contained in the blackened layer 22 may be an intermetallic compound containing the first metal and the second metal. When the first metal is Cu and the second metal is Pd, the intermetallic compound may be an intermetallic compound containing Cu and Pd. Examples of such intermetallic compounds include Cu 3.82 Pd 0.18 , Cu3Pd, Cu3PdPd, CuPd. Among them, the intermetallic compound is preferably Cu 3.82 Pd 0.18 In this case, the resistance value of the blackened layer 22 is effectively reduced, and thus the resistance value of the conductive portion 20 is effectively reduced as a whole. Therefore, the conductivity of the conductive film 100 can be effectively improved.

[0070] The space group of the crystal structure contained in the blackened layer 22 is Pm-3m. In the blackened layer 22, the content of the crystal structure having the space group Pm-3m may be 70% by mass or more, 80% by mass or more, or 100% by mass.

[0071] The space group of the crystal structure can be determined by observing an electron beam diffraction image of a region observed by a transmission electron microscope (TEM) in a cross section in the thickness direction of the blackened layer 22. Specifically, if the (110) plane exists in the electron beam diffraction image, the space group of the crystal structure can be determined to be Pm-3m.

[0072] The maximum size of the grain diameter contained in the black layer 22 is not particularly limited, and is preferably less than 30 nm, and more preferably less than 25 nm. When the maximum size of the grain diameter contained in the black layer 22 is less than 30 nm, compared with the case where the maximum size of the grain diameter contained in the black layer 22 is greater than 30 nm, when light is incident on the conductive portion 20, the visible light is not easily scattered on the black layer 22 and is easily absorbed. Therefore, the reflection of visible light in the conductive portion 20 is effectively suppressed. Therefore, the invisibility of the conductive portion 20 can be improved.

[0073] The maximum size of the crystal grains included in the blackened layer 22 may be 5 nm or more, or 8 nm or more.

[0074] The “maximum size of the crystal grain diameter” in the present disclosure refers to the maximum size of the crystal grains among the 10 crystal grains included in the field of view when any region of the cross section in the thickness direction of the blackened layer 22 is observed by TEM.

[0075] In addition, the size of a crystal grain refers to the distance between two points on a grain boundary of a crystal grain when the distance between the two points is the maximum.

[0076] The surface roughness of the black layer 22 is not particularly limited, but is preferably less than 100 nm, more preferably less than 80 nm, and further preferably less than 50 nm. When the surface roughness of the black layer 22 is less than 100 nm, the flatness of the surface of the black layer 22 becomes higher, and thus, the resistance value of the black layer 22 can be further reduced. This is particularly effective when the high-frequency current flowing to the conductive portion 20 mainly flows on the surface of the conductive portion 20 due to the skin effect.

[0077] Furthermore, “100 nm” means a size sufficiently smaller than the lower limit of the wavelength of visible light.

[0078] The surface roughness of the blackened layer 22 may be greater than or equal to 5 nm, greater than or equal to 10 nm, or greater than or equal to 15 nm.

[0079] The “surface roughness” in the present disclosure is the maximum height, specifically, the value of the maximum height in the surface width of 300 nm of the blackened layer 22 measured when a cross section in the thickness direction of the blackened layer 22 is observed by TEM.

[0080] The surface roughness of the blackened layer 22 may be smaller than that of the main body 21 , or may be greater than that of the main body 21 , but is preferably smaller than that of the main body 21 .

[0081] In this case, compared with the case where the surface roughness of the black layer 22 is greater than the surface roughness of the surface of the main body 21, the surface of the black layer 22 has a higher flatness than the surface of the main body 21, and therefore, the resistance value of the black layer 22 is further reduced. Therefore, the resistance value of the conductive part 20 is effectively reduced as a whole, and the conductivity of the conductive film 100 can be effectively improved. In particular, even in the case where the high-frequency current flowing to the conductive part 20 mainly flows on the surface of the conductive part 20 due to the skin effect, the influence caused by the surface of the black layer 22 is small, and therefore, the conductivity of the conductive film 100 can be further improved.

[0082] The ratio R3 of the surface roughness of the blackened layer 22 to the surface roughness of the main body 21 may be less than 1, preferably 0.9 or less, and more preferably 0.8 or less. The ratio R3 may be 0.2 or more, or 0.3 or more.

[0083] The thickness of the black layer 22 is not particularly limited, but is preferably 100 nm or less, more preferably 80 nm or less, and further preferably 70 nm or less. When the thickness of the black layer 22 is 100 nm or less, the overall resistance value of the conductive portion 20 can be further reduced.

[0084] The thickness of the blackened layer 22 may be greater than 10 nm, greater than 15 nm, or greater than 20 nm.

[0085] (basal layer)

[0086] The base layer 23 includes a third metal.

[0087] The third metal may be a metal selected from Pd, Cu, Ni, Al, Co, Au, Ag, Pd, Rh, Pt, In and Sn, a metal selected from Pd, Cu, Ni and Al, a metal selected from Pd, Cu and Ni, or Ni. The third metal may be a single metal or a combination of two or more. The third metal may be the same as or different from the first metal. For example, the third metal may be nickel and the first metal may be copper.

[0088] The thickness of the base layer 23 may be 5 nm or more, 10 nm or more, or 30 nm or less, or 500 nm or less, 300 nm or less, or 150 nm or less.

[0089] (Resin layer)

[0090] like Figure 2 As shown, the resin layer 30 may include a first resin layer 31. The first resin layer 31 includes resin.

[0091] The total light transmittance of the first resin layer 31 may be 90 to 100%. The haze of the first resin layer 31 may be 0 to 5%.

[0092] The resin contained in the first resin layer 31 can be a cured product of a curable resin composition (a photocurable resin composition or a thermosetting resin composition). The curable resin composition contains a curable resin. As a curable resin, acrylic resin, amino resin, cyanate resin, isocyanate resin, polyimide resin, epoxy resin, oxetane resin, polyester resin, allyl resin, phenolic resin, benzoxazine resin, xylene resin, ketone resin, furan resin, COPNA (condensed polycyclic polynuclear aromatic) resin, silicone resin, dicyclopentadiene resin, benzocyclobutene resin, episulfide resin, ene-thiol resin, polyazomethine resin, polyvinyl benzyl ether compound, acenaphthylene, and ultraviolet curing resin containing functional groups such as unsaturated double bonds, cyclic ethers and vinyl ethers that undergo polymerization reactions under ultraviolet light.

[0093] The thickness of the first resin layer 31 may be, for example, 500 nm or more, 1000 nm or more, or 2000 nm or less, 10 μm or less, or 5 μm or less.

[0094] (Second resin layer)

[0095] like Figure 2 As shown, the resin layer 30 may include a second resin layer 32 in addition to the first resin layer 31. The second resin layer 32 is provided between the first resin layer 31 and the substrate 10.

[0096] The second resin layer 32 includes a resin. The second resin layer 32 may further include first inorganic particles.

[0097] The resin contained in the second resin layer 32 can also be a cured product of a curable resin composition (a photocurable resin composition or a thermosetting resin composition). The curable resin composition contains a curable resin. As a curable resin, for example, acrylic resin, amino resin, cyanate resin, isocyanate resin, polyimide resin, epoxy resin, oxetane resin, polyester resin, allyl resin, phenolic resin, benzoxazine resin, xylene resin, ketone resin, furan resin, COPNA (condensed polycyclic polynuclear aromatic) resin, silicone resin, dicyclopentadiene resin, benzocyclobutene resin, episulfide resin, ene-thiol resin, polyazine resin, polyvinyl benzyl ether compound, acenaphthylene, and ultraviolet curing resin containing unsaturated double bonds, cyclic ethers and vinyl ethers, etc., which undergo polymerization reaction under ultraviolet light. The curable resin can also be a single one or a combination of two or more.

[0098] As the first inorganic particles, for example, silicon dioxide, aluminum oxide, titanium dioxide, tantalum oxide, zirconium oxide, silicon nitride, barium titanate, barium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, gallium oxide, spinel, mullite, cordierite, talc, aluminum titanate, barium silicate, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate, hydrotalcite, mica, calcined kaolin and carbon, etc. The second inorganic particles can be used alone or in combination of two or more.

[0099] The second resin layer 32 is preferably made of a material having higher adhesion to the base material 10 than the first resin layer 31 .

[0100] The thickness of the second resin layer 32 may be, for example, 5 nm or more, 100 nm or more, or 200 nm or less, or 10 μm or less, 5 μm or less, or 2 μm or less.

[0101] The resin layer 30 may further include second inorganic particles at least between the second resin layer 32 and the base layer 23. The second inorganic particles may be a metal selected from Pd, Cu, Ni, Al, Co, Au, Ag, Pd, Rh, Pt, In, and Sn, a metal selected from Pd, Cu, Ni, and Al, a metal selected from Pd, Cu, and Ni, or Pd. The second inorganic particles may be a single one or a combination of two or more. The resin layer 30 may further include second inorganic particles between the second resin layer 32 and the first resin layer 31.

[0102] (Groove)

[0103] exist Figure 2 In the embodiment, the bottom surface of the groove 33 of the resin layer 30 is formed on the first resin layer 31. The groove 33 may be formed to penetrate the first resin layer 31.

[0104] <<Method for producing conductive film>>

[0105] Next, an embodiment of a method for producing a conductive film according to the present disclosure will be described.

[0106] The manufacturing method of the conductive film disclosed in the present invention includes a conductive portion forming step of forming a conductive portion on the main surface side of a substrate. In the conductive portion forming step, the conductive portion has: a main body portion including a first metal, and a blackened layer covering the surface of the main body portion on at least the side opposite to the substrate, the blackened layer includes the first metal and a second metal different from the first metal, and the blackened layer is formed in a manner having a crystal structure with a space group of Pm-3m.

[0107] Below, refer to Figure 3 to Figure 6 In the case where the conductive film is the conductive film 100 described above, a method for manufacturing the conductive film 100 will be described.

[0108] Figure 3 is a cross-sectional view showing the first structure obtained in the first step, Figure 4 is a cross-sectional view showing the second structure obtained in the second step, Figure 5 is a cross-sectional view showing the third structure obtained in the third step, Figure 6 It is a cross-sectional view showing the fifth structure obtained in the fifth step.

[0109] The method for manufacturing the conductive film 100 includes, for example, a first step of forming a resin film 30A on the main surface 10S of the substrate 10 to obtain a first structure 101 (see Figure 3 ); in the resin film 30A, the surface on the side opposite to the substrate 10 is formed by an imprint method to form a groove 33 to form a resin layer 30, to obtain a second step of the second structure 102 (reference Figure 4 ); forming a base layer 23 as a seed layer containing a third metal in the groove 33 to obtain a third structure 103 (refer to the third step Figure 5 ); in the third structure 103, a catalyst layer (not shown) is formed on the base layer 23 to obtain a fourth structure; on the base layer 23, a metal plating 24 containing a first metal is grown by a plating method to obtain a fifth structure 104 (refer to Figure 6 ); and, a sixth step of blackening the exposed surface of the grown metal plating 24 by using a blackening treatment liquid containing a second metal, making the exposed surface portion of the metal plating 24 into a blackening layer 22, and forming a conductive portion 20 having a base layer 23, a main body 21 and a blackening layer 22 (refer to Figure 2 ). Here, the third step to the sixth step correspond to the above-mentioned conductive portion forming step.

[0110] In the first step, the resin film 30A is a laminate of the second resin film 32A to be the second resin layer 32 and the first resin film 31A to be the first resin layer 31 (see Figure 3 ).

[0111] In the first process, for example, first, after forming the second resin film 32A containing the first inorganic particles and the resin, a resin layer containing the second inorganic particles and the resin as a nucleating agent is formed. Thereafter, the resin layer containing the second inorganic particles is removed by ashing. At this time, the second inorganic particles as the nucleating agent remain on the surface of the second resin film 32A. Next, the first resin film 31A is formed on the second resin film 32A via the second inorganic particles.

[0112] In the second step, for example, a mold having a convex portion is pressed into the resin film 30A, and then the mold is pulled out from the resin film 30A, thereby forming the groove 33 on the resin film 30A to form the resin layer 30. At this time, the groove 33 is formed in a manner that the second inorganic particles existing on the surface of the second resin film 32A are exposed, that is, the groove 33 is formed in a manner that penetrates the first resin film 31A.

[0113] When the first resin film 31A includes a curable resin composition, the first resin film 31A may be cured with a mold pressed into the first resin film 31A to form the first resin layer 31. Specifically, when the first resin film 31A includes a photocurable resin composition, the first resin film 31A may be irradiated with ultraviolet rays with a mold pressed into the first resin film 31A to cure the first resin film 31A to form the first resin layer 31.

[0114] In the third step, the base layer 23 functions as a seed layer when the metal plating 24 is grown in the fifth step. The base layer 23 can be formed, for example, by immersing the second structure 102 in an electroless plating solution for base layer formation, thereby using the second inorganic particles on the second resin film 32A as nucleating agents.

[0115] In the fourth step, the catalyst layer can be formed on the base layer 23 by immersing the third structure 103 in a catalyst solution containing a catalyst.

[0116] As the catalyst in the catalyst solution, at least one metal selected from the group consisting of copper, nickel, cobalt, palladium, silver, gold, platinum, and tin can be used.

[0117] In the fifth step, for example, the base layer 23 can be used as a seed layer to grow the metal plating 24 on the base layer 23. The growth of the metal plating 24 is preferably performed by an electroless plating method. In this case, compared with the case where the metal plating 24 is grown by an electrolytic plating method, the grain boundaries and impurities are more contained in the metal plating 24, and the second metal in the blackening treatment solution in the sixth step is not easy to diffuse into the metal plating 24, and the blackening layer 22 containing more of the first metal than the second metal can be formed in a short time. In the case of growing the metal plating 24 by an electroless plating method, specifically, by immersing the fourth structure, for example, in an electroless plating solution, the metal plating 24 grows on the base layer 23 starting from the catalyst layer.

[0118] In the sixth step, for example, a blackening treatment liquid containing the second metal is used to blacken the exposed surface of the grown metal plating 24, thereby replacing part of the first metal in the metal plating 24 with the second metal, thereby forming a blackened layer 22 containing the first metal and the second metal.

[0119] In the blackening treatment, the metal plating 24 can be brought into contact with a blackening treatment liquid containing a second metal. At this time, when the metal plating 24 is grown by an electroless plating method, the contact time between the metal plating 24 and the blackening treatment liquid can be set to, for example, 150 seconds or less, or 120 seconds or less. Even if the contact time between the metal plating 24 and the blackening treatment liquid is 100 seconds or less, the blackening layer 22 can be obtained.

[0120] The contact time between the metal plating 24 and the blackening treatment liquid may be, for example, 30 seconds or longer, or 45 seconds or longer.

[0121] The temperature of the blackening treatment liquid is not particularly limited, and may be, for example, 20° C. or higher, or 25° C. or higher. The temperature of the blackening treatment liquid may be, for example, 50° C. or lower, or 45° C. or lower.

[0122] In addition, when the first metal is Cu, the second metal is Pd, and a Cu 3.18 Pd 0.82 In the case of a compound represented by the composition formula of , even if the ratio of Pd to Cu is changed in a wide range, a Cu-containing compound can be formed in the blackened layer 22. 3.18 Pd 0.82 That is, without strictly controlling the ratio of Pd to Cu, it is possible to easily form a Cu-containing black layer 22. 3.18 Pd 0.82 Therefore, the contact time between the metal plating 24 and the blackening treatment liquid, the temperature of the blackening treatment liquid, etc., which are required to adjust the ratio of Pd to Cu, can be set within a wide range.

[0123] <<Display device>>

[0124] Next, embodiments of the display device of the present disclosure will be described.

[0125] The display device of the present disclosure includes a conductive film. As the conductive film, the conductive film 100 described above can be used.

[0126] According to the display device, the conductive film can improve the conductivity while suppressing the reflection of light. Therefore, in the display device, the invisibility of the conductive part can be improved. In addition, since the conductivity can be improved, the heat generation of the conductive part can be suppressed.

[0127] The conductive film 100 can be used as, for example, a planar transparent antenna.

[0128] The display device may be, for example, a liquid crystal display device or an organic EL display device.

[0129] Figure 7 It is a cross-sectional view showing one embodiment of the display device of the present disclosure.

[0130] Figure 7 The display device 200 shown includes an image display unit 201, a conductive film 100, a polarizing plate 202, and a cover glass 203. On one surface of the image display unit 201, the conductive film 100, the polarizing plate 202, and the cover glass 203 are stacked in this order from the image display unit 201 side.

[0131] In addition, the structure of the display device is not limited to Figure 7 The form of the conductive film 100 can be changed as needed. For example, the polarizing plate 202 can also be provided between the image display unit 201 and the conductive film 100. The image display unit 201 can also be a liquid crystal display unit, for example. As the polarizing plate 202 and the cover glass 203, the polarizing plate and the cover glass commonly used in the display device can be used. The polarizing plate 202 and the cover glass 203 may not be provided.

[0132] For example, in the above embodiment, the conductive part 20 is fixed to the base material 10 via the resin layer 30 , but the conductive part 20 may be directly fixed to the base material 10 . In this case, the resin layer 30 may be omitted.

[0133] In the above embodiment, the main body 21 of the conductive portion 20 is composed only of the base provided inside the groove 33 when the conductive portion 20 is viewed from above (i.e., when viewed from a direction perpendicular to the main surface 10S of the substrate 10). Figure 8 As shown in the conductive film 110 , the main body 21 includes a base 21 a and protruding portions 21 b provided on both sides thereof.

[0134] When the main body 21 includes the base 21 a and the protrusions 21 b provided on both sides of the base 21 a , the protrusions 21 b are preferably in contact with a surface 30S of the resin layer 30 on the opposite side to the base 10 .

[0135] In this case, the main body 21 has protrusions 21b provided on both sides of the base 21a, and the protrusions 21b are in contact with the surface 30S on the side opposite to the substrate 10 in the resin layer 30, so that the contact area between the resin layer 30 and the conductive part 20 is increased compared with the case where the main body 21 does not have the protrusions 21b. Therefore, the adhesion between the resin layer 30 and the conductive part 20 is further improved, and the conductive part 20 is not easy to be peeled off from the resin layer 30. In addition, the thermal expansion coefficient of the conductive part 20 is generally smaller than the thermal expansion coefficient of the resin layer 30. Therefore, the base 21a is not easy to expand in the thickness direction compared with the resin layer 30. Therefore, even if the resin layer 30 is to expand in the thickness direction due to the increase in the surrounding temperature, the expansion of the resin layer 30 in the thickness direction is suppressed by the protrusions 21b, and the conductive part 20 is not easy to be peeled off from the resin layer 30.

[0136] In addition, when the main body 21 is composed of a base 21a and protrusions 21b provided on both sides thereof, as shown in FIG. Figure 8 As shown, the blackened layer 22 may cover the first surface 21 c and the second surface 21 d of the main body 21 . In this case, even if light is incident on the main surface 10S of the substrate 10 , reflection of the light is suppressed by the blackened layer 22 .

[0137] In addition, in the above-mentioned embodiment, the bottom surface of the groove 33 of the resin layer 30 is formed in the first resin layer 31, but it can also be formed in the second resin layer 32 or in the substrate 10. In this case, compared with the case where the bottom surface of the groove 33 is formed in the first resin layer 31, the aspect ratio of the conductive part 20 can be improved, and the conductivity of the conductive part 20 can be further improved. Here, the aspect ratio refers to the ratio of the thickness of the conductive part 20 to the width of the conductive part 20. The width of the conductive part 20 refers to the width in the direction orthogonal to the extension direction of the conductive part 20 when the conductive part 20 is viewed from the black layer 22 side, and the thickness of the conductive part 20 refers to the distance between the position closest to the substrate 10 side and the position farthest from the substrate 10 in the conductive part 20.

[0138] The present disclosure includes the following structural examples in addition to the conductive film described in the means for solving the problem, but is not limited to the following structural examples.

[0139] In the conductive film according to one aspect of the present disclosure, in the blackened layer, the mass content of the first metal may be greater than the mass content of the second metal.

[0140] In this case, since the resistance value of the blackened layer is effectively reduced, the resistance value of the conductive portion is effectively reduced as a whole, and thus the conductivity of the conductive film can be effectively improved.

[0141] In the conductive film, the first metal may be copper, and the second metal may be palladium.

[0142] In the above-mentioned conductive film, the above-mentioned blackened layer may contain Cu 3.18 Pd 0.82 A compound represented by the composition formula.

[0143] In this case, since the resistance value of the blackened layer is effectively reduced, the resistance value of the conductive portion is effectively reduced as a whole, and thus the conductivity of the conductive film can be effectively improved.

[0144] In the conductive film, the blackened layer may include crystal grains, and the maximum size of the crystal grains may be less than 30 nm.

[0145] In this case, when light is incident on the conductive part, the visible light is not easily scattered on the black layer and is easily absorbed. Therefore, the reflection of the visible light in the conductive part is effectively suppressed. Therefore, the invisibility of the conductive part can be improved.

[0146] In the conductive film, the blackened layer may have a thickness of 100 nm or less.

[0147] In this case, by setting the thickness of the blackened layer to 100 nm or less, the resistance value of the entire conductive portion can be further reduced.

[0148] In the above-mentioned conductive film, the surface roughness of the above-mentioned blackened layer may be less than 100 nm.

[0149] In this case, since the flatness of the surface of the blackened layer is improved, the resistance value of the blackened layer can be further reduced. This is particularly effective when the high-frequency current flowing to the conductive portion mainly flows on the surface of the conductive portion due to the skin effect.

[0150] In the conductive film, the blackened layer may have a surface roughness smaller than a surface roughness of a surface of the main body portion.

[0151] In this case, compared with the case where the surface roughness of the blackened layer is greater than the surface roughness of the surface of the main body, since the surface of the blackened layer has a higher flatness than the surface of the main body, the resistance value of the blackened layer is further reduced. Therefore, the resistance value of the conductive part is effectively reduced as a whole, and the conductivity of the conductive film can be effectively improved. In particular, even in the case where the high-frequency current flowing to the conductive part mainly flows on the surface of the conductive part due to the skin effect, the influence caused by the surface of the blackened layer is small, and therefore, the conductivity of the conductive film can be further improved.

[0152] The conductive film may further include a resin layer provided on the main surface side of the substrate, the resin layer may have a groove, and the conductive portion may be filled in the groove.

[0153] In this case, in the conductive film, the resin layer has grooves, and the conductive portion is filled in the grooves, so that the conductive portion is stably fixed to the substrate.

[0154] In the conductive film, at least in a portion of an interface between the main body of the conductive portion and the resin layer, the main body and the resin layer may be in direct contact without the blackened layer interposed therebetween.

[0155] In this case, even when a high-frequency current flowing to the conductive portion flows in the surface portion of the conductive portion due to the skin effect, the conductivity of the conductive portion can be further improved because the proportion of the blackened layer in the surface portion of the conductive portion is reduced.

[0156] In the conductive film, the conductive portion may include a base disposed inside the groove and protrusions disposed on both sides of the base when the conductive portion is viewed from above, and the protrusions are in contact with a surface of the resin layer on the opposite side to the substrate.

[0157] In this case, the main body has projections on both sides of the base, and the projections are in contact with the surface of the side opposite to the base material in the resin layer, so that the contact area between the resin layer and the conductive part increases compared with the situation that the main body does not have projections. Therefore, the adhesion between the resin layer and the conductive part is further improved, and the conductive part is not easy to peel off from the resin layer. In addition, the thermal expansion coefficient of the conductive part is usually smaller than the thermal expansion coefficient of the resin layer. Therefore, the base is not easy to expand in the thickness direction compared with the resin layer. Therefore, even if the resin layer is to expand in its thickness direction because of the surrounding temperature increase, the expansion in the thickness direction of the resin layer will also be suppressed by the projections, and the conductive part is not easy to peel off from the resin layer.

[0158] Another aspect of the present disclosure provides a display device including the conductive film.

[0159] According to the display device, the conductive film can improve the conductivity while suppressing the reflection of light. Therefore, in the display device, the invisibility of the conductive part can be improved. In addition, since the conductivity can be improved, the heat generation of the conductive part can be suppressed.

[0160] Example

[0161] Hereinafter, the present disclosure will be specifically described by way of examples, but the present invention is not limited to the following examples.

[0162] (Example 1)

[0163] As a substrate, a COP film (thickness: 100 μm) was prepared.

[0164] Next, a second resin composition (the second resin composition containing silica as first inorganic particles, acrylic resin as resin, and methyl ethyl ketone (MEK) as solvent) was applied onto the main surface of the substrate and dried to form a second resin film having a thickness of 0.3 μm.

[0165] Next, a Pd-containing resin composition (the Pd-containing resin composition contains Pd as second inorganic particles, acrylic resin as resin, and methyl ethyl ketone (MEK) as solvent) was applied and dried to form a 60 μm-thick Pd-containing resin layer.

[0166] Next, after the resin in the Pd-containing resin layer was removed by ashing, the first resin composition (the first resin composition containing acrylic resin as a resin) was applied on the Pd particles remaining on the second resin film to form a first resin film with a thickness of 2 μm.

[0167] In this way, a resin film having a thickness of 2.3 μm was formed to obtain a first structure.

[0168] Next, a resin layer is formed by forming grooves on the surface of the resin film on the side opposite to the substrate by an imprinting method to obtain a second structure. Specifically, a mold having a grid-like protrusion is pressed into the above-mentioned resin film, and then the mold is pulled out from the resin film, thereby forming a grid pattern with grooves of 2 μm in depth and 1.5 μm in width on the resin film. At this time, the Pd particles remaining on the second resin film are exposed. Thus, a resin layer is formed. At this time, the pitch of the grid pattern is 100 μm.

[0169] Next, the second structure is immersed in an electroless plating solution containing nickel sulfate and sodium hypophosphite, so that Ni plating grows on the Pd particles remaining on the second resin film, and a Ni layer as a base layer is formed in the groove to obtain a third structure. The third structure formed with the Ni layer is immersed in a Pd catalyst solution to form a Pd catalyst layer to obtain a fourth structure.

[0170] Next, the fourth structure obtained is immersed in an electroless plating solution containing copper sulfate and formalin, so that the Cu plating grows on the Ni layer starting from the Pd catalyst layer, thereby forming a Cu layer in the groove. Thus, a conductive layer with a grid-like pattern is formed in the groove, and a fifth structure is obtained.

[0171] Next, the fifth structure is immersed in a blackening treatment liquid containing palladium at room temperature (25°C) for 60 seconds, and the exposed surface of the grown copper plating is blackened, thereby making the surface layer of the copper plating into a blackened layer, forming a conductive part having a base layer, a main body and a blackened layer, and forming a grid wiring having a conductive part on a grid pattern having grooves.

[0172] As described above, a conductive film is obtained.

[0173] By performing TEM observation and electron beam diffraction analysis on the conductive film obtained as described above, the thickness of the main body, the composition ratio of Cu and Pd in ​​the black layer (Cu:Pd, mass ratio), the thickness of the black layer, the maximum size of the crystal grains of the black layer, the crystal structure (lattice) of the black layer, the space group of the crystal structure of the black layer, and the compound phase constituting the crystal structure of the black layer were obtained. The results are shown in Table 1.

[0174] Furthermore, TEM observation and electron beam diffraction analysis were performed using a scanning transmission electron microscope (STEM) equipped with an EDS detector (manufactured by JEOL Ltd., product name: JEM-2011F).

[0175] (Comparative Example 1)

[0176] A conductive film was produced in the same manner as in Example 1, except that the fifth structure was immersed in a blackening treatment liquid containing palladium at room temperature (25° C.) for 180 seconds.

[0177] By performing TEM observation and electron beam diffraction analysis on the conductive film obtained as described above in the same manner as in Example 1, the thickness of the main body, the composition ratio of Cu and Pd in ​​the blackened layer (Cu:Pd, mass ratio), the thickness of the blackened layer, the maximum size of the crystal grains of the blackened layer, the crystal structure (lattice) of the blackened layer, the space group of the crystal structure of the blackened layer, and the compound phase constituting the crystal structure of the blackened layer were obtained. The results are shown in Table 1.

[0178] (Comparative Example 2)

[0179] A conductive film was produced in the same manner as in Example 1 except that the blackening treatment was not performed and the blackening layer was not formed.

[0180] In addition, since the blackening layer is not formed in Comparative Example 2, the thickness of the main body, the composition ratio of Cu and Pd in ​​the blackening layer (Cu:Pd, mass ratio), the thickness of the blackening layer, the maximum size of the grains of the blackening layer, the crystal structure (lattice) of the blackening layer, the space group of the crystal structure of the blackening layer, and the compound phase constituting the crystal structure of the blackening layer are shown as “-” in Table 1.

[0181] <Evaluation>

[0182] (1) Light reflection suppression effect

[0183] In order to evaluate the light reflection suppression effect of the conductive film obtained in Example 1, Comparative Example 1 and Comparative Example 2, an evaluation sample was prepared. Specifically, the evaluation sample was prepared in the same manner as in Example 1, Comparative Example 1 or Comparative Example 2, except that no resin layer was formed on the main surface of the substrate and a conductive portion was formed on the entire main surface of the substrate. Then, the reflectance of the evaluation sample was measured for light with a wavelength of 550nm using a spectrophotometer. The results are shown in Table 1.

[0184] (2) Electrical conductivity

[0185] The mesh wiring of the conductive film obtained in Example 1, Comparative Example 1, and Comparative Example 2 was measured for surface resistance (Ω / sq) using a four-terminal resistance meter, and the conductivity was evaluated based on the surface resistance.

[0186]

[0187] From the results shown in Table 1, it can be seen that, in the conductive film of Example 1, the reflectance of light having a wavelength of 550 nm is the same as that of Comparative Example 1, but the surface resistance value of the conductive portion is sufficiently lowered.

[0188] This confirmed that the conductive film of the present disclosure can improve conductivity while suppressing reflection of light.

[0189] Furthermore, the outline of the present disclosure is as follows.

[0190] [1] A conductive film, comprising: a substrate and a conductive portion arranged on the main surface side of the substrate, the conductive portion comprising: a main body portion, which contains a first metal; and a blackening layer, which covers at least the surface of the main body portion on the side opposite to the substrate, the blackening layer contains the first metal and a second metal different from the first metal, and the blackening layer has a crystal structure with a space group of Pm-3m.

[0191] [2] The conductive film according to [1], wherein in the blackened layer, the mass content of the first metal is greater than the mass content of the second metal.

[0192] [3] The conductive film according to [1] or [2], wherein the first metal is copper and the second metal is palladium.

[0193] [4] The conductive film according to [3], wherein the blackened layer contains Cu 3.18 Pd 0.82 A compound represented by the composition formula.

[0194] [5] The conductive film according to any one of [1] to [4], wherein the blackened layer includes crystal grains, and the maximum size of the crystal grains is less than 30 nm.

[0195] [6] The conductive film according to any one of [1] to [5], wherein the thickness of the blackened layer is 100 nm or less.

[0196] [7] The conductive film according to any one of [1] to [6], wherein the surface roughness of the blackened layer is less than 100 nm.

[0197] [8] The conductive film according to any one of [1] to [7], wherein the surface roughness of the blackened layer is smaller than the surface roughness of the surface of the main body portion.

[0198] [9] The conductive film according to any one of [1] to [8], further comprising a resin layer provided on the main surface side of the substrate, the resin layer having a groove, and the conductive portion is filled in the groove.

[0199]

[10] The conductive film according to [9], wherein, at least in a portion of an interface between the main body of the conductive portion and the resin layer, the main body and the resin layer are in direct contact without the blackened layer interposed therebetween.

[0200]

[11] A conductive film according to [9] or

[10] , wherein the main body has a base arranged on the inner side of the groove when the main body is viewed from above and protrusions arranged on both sides of the base, and the protrusions are in contact with the surface of the resin layer on the side opposite to the substrate.

[0201]

[12] A display device comprising the conductive film according to any one of [1] to

[11] .

[0202] Description of Reference Numerals

[0203] 10. Base material

[0204] 10S main surface,

[0205] 20 conductive part,

[0206] 21Main body,

[0207] 21a base,

[0208] 21b protrusion,

[0209] 22 black layer,

[0210] 30 resin layers,

[0211] 33 grooves,

[0212] 100 conductive film,

[0213] 200 display devices.

Claims

1. A conductive film, wherein: have: substrate; and a conductive portion provided on the main surface side of the substrate, The conductive part has: a body portion comprising a first metal; and a blackened layer covering at least a surface of the main body portion on a side opposite to the substrate, The blackened layer includes the first metal and a second metal different from the first metal, The blackened layer has a crystal structure with a space group of Pm-3m.

2. The conductive film according to claim 1, wherein In the blackened layer, the mass content of the first metal is greater than the mass content of the second metal.

3. The conductive film according to claim 1, wherein The first metal is copper, and the second metal is palladium.

4. The conductive film according to claim 3, wherein The blackened layer contains Cu 3.18 Pd 0.82 A compound represented by the composition formula.

5. The conductive film according to claim 1, wherein The blackened layer contains crystal grains, and the maximum size of the crystal grains is less than 30 nm.

6. The conductive film according to claim 1, wherein The thickness of the blackened layer is less than 100 nm.

7. The conductive film according to claim 1, wherein The surface roughness of the blackened layer is less than 100 nm.

8. The conductive film according to claim 1, wherein The surface roughness of the blackened layer is smaller than the surface roughness of the surface of the main body.

9. The conductive film according to claim 1, wherein The conductive film further comprises a resin layer provided on the main surface side of the substrate. The resin layer has a groove, and the conductive portion is filled in the groove.

10. The conductive film according to claim 9, wherein At least a portion of an interface between the main body portion of the conductive portion and the resin layer, the main body portion and the resin layer are in direct contact without the blackened layer interposed therebetween.

11. The conductive film according to claim 9, wherein The main body has a base provided inside the groove and protrusions provided on both sides of the base when the main body is viewed from above, and the protrusions are in contact with a surface of the resin layer on the opposite side to the base.

12. A display device, wherein: A conductive film according to any one of claims 1 to 11.

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