Conductive film

Abstract

A groove part (9a) and a groove part (9b) which extend linearly are formed on a first surface (5a) of a substrate (5). When an angle (C1) formed by a bottom surface (91a) and a side surface (92a) of the groove part (9a) is smaller than an angle (C2) formed by a bottom surface (91b) and a side surface (92b) of the groove part (9b), a thickness (L1) of a side surface part (312a) of the adhesion layer (31a) formed along the side surface (92a) of the groove part (9a) is smaller than a thickness (L2) of a side surface part (312b) of the adhesion layer (31b) formed along the side surface (92b) of the groove part (9b).

Description

Technical Field

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

[0002] Conventionally, as for a touch sensor using a conductive film, for example, a touch sensor disclosed in Patent Document 1 is known.

[0003] Patent document 1 discloses a touch sensor provided with a visible area (display area for displaying an image). The touch sensor includes: a cover member (polarizing plate) capable of transmitting light, a substrate having a surface opposite to the back surface of the cover member, and a plurality of electrodes (contact electrodes) provided on the surface of the substrate and arranged in the visible area.

[0004] A plurality of bottomed grooves (conductive layer forming grooves, wiring forming grooves) are provided on the surface of the substrate. Each electrode is composed of a plurality of fine wires arranged on the surface side of the substrate in a manner forming a predetermined pattern (mesh-like pattern). Each fine wire is composed of a conductive layer formed by burying a metal material having excellent conductivity in each groove. The outer surface of the conductive layer is arranged opposite to the cover member (polarizing plate) and is formed into a flat surface flush with the surface of the substrate.

[0005] Patent document 1: WO2021 / 131319A1 Summary of the invention

[0006] -Technical problem to be solved by the invention-

[0007] In the conductive film of Patent Document 1, each thin wire includes a conductive layer and an adhesive layer. The conductive layer is buried in the groove via the adhesive layer formed on the groove in a thin film form. The conductive layer ensures adhesion to the groove through the adhesive layer.

[0008] However, for example, when a current flows through the conductive layer, the temperature in the conductive layer and the close-contact layer may sometimes increase due to the heat of the conductive layer and the close-contact layer. In the case where the conductive layer is composed of metal and the close-contact layer is composed of a metal compound, if the temperature in the conductive layer and the close-contact layer increases, the volume of the conductive layer will expand more than the volume of the close-contact layer. Therefore, the close-contact layer is compressed due to the expansion of the conductive layer. In particular, in the case where the groove portion is formed in a concave bottomed shape, since the two side surfaces of the groove portion are arranged opposite to each other, the close-contact layer formed along the side surface of the groove portion is compressed by the conductive layer.

[0009] Furthermore, when the adhesion layer is composed of a metal compound, the thicker the adhesion layer is, the higher the rigidity of the adhesion layer is, and stress due to expansion of the conductive layer is more likely to be generated in the conductive layer, thereby causing destruction of the adhesion layer.

[0010] The present disclosure is completed to solve the above technical problems, and its purpose is to make the conductive film a structure resistant to external interferences such as temperature changes and erosion.

[0011] - Technical solution for solving the technical problem -

[0012] To achieve the above object, an embodiment of the present disclosure is a conductive film, which includes a substrate having a first surface. On the first surface of the substrate, there are provided a bottomed first groove portion and a second groove portion extending linearly. In the first groove portion, a first conductive layer made of metal is embedded with a first metal compound layer made of metal compound therebetween. In the second groove portion, a second conductive layer made of metal is embedded with a second metal compound layer made of metal compound therebetween. The first groove portion includes a first bottom portion and a first side portion, and the first side portion connects the first bottom portion to the opening of the first groove portion. The second groove portion includes a second bottom portion and a second side portion, and the second side portion connects the second bottom portion to the opening of the second groove portion. The first metal compound layer includes a first layer formed along the first side portion, and the second metal compound layer includes a second layer formed along the second side portion. When the first angle formed by the first bottom portion and the first side portion, i.e., the first angle, is smaller than the second angle formed by the second bottom portion and the second side portion, i.e., the second angle, the first thickness of the first layer, i.e., the first thickness, is smaller than the second thickness of the second layer, i.e., the second thickness.

[0013] - Effects of the invention -

[0014] According to the present disclosure, it is possible to make the conductive film a structure resistant to external interferences such as temperature changes and erosion. Description of the drawings

[0015] Figure 1 is an overall perspective view of the contact sensor according to the embodiment of the present disclosure;

[0016] Figure 2 is a top view briefly showing the connection state between the substrate and the flexible wiring board;

[0017] Figure 3 is a perspective view briefly showing the structures of the substrate, the first electrode, the second electrode, the first wiring portion, and the second wiring portion when viewed from the first surface side of the substrate;

[0018] Figure 4 is a top view showing the structures of the substrate, the first electrode, and the first wiring portion when viewed from the first surface side of the substrate;

[0019] Figure 5 is a bottom view showing the structures of the substrate, the second electrode, and the second wiring portion when viewed from the second surface side of the substrate;

[0020] Figure 6 is along Figure 1Cross-sectional view taken along line VI-VI;

[0021] Figure 7 Partial enlarged top view showing a part of the first electrode in an enlarged manner;

[0022] Figure 8 is along Figure 1 Cross-sectional view taken along line VIII-VIII;

[0023] Figure 9 Partial enlarged top view showing a part of the first wiring portion in an enlarged manner;

[0024] Figure 10 Partial enlarged top view showing a part of the connection pad in an enlarged manner;

[0025] Figure 11 Cross-sectional view briefly showing the cross-sectional state of the fine wires constituting the first electrode and the second electrode;

[0026] Figure 12 Cross-sectional view briefly showing the cross-sectional state of the fine wires constituting the first wiring portion, the second wiring portion, and the connection pad;

[0027] Figure 13 briefly shows Figure 11 Cross-sectional view of the groove portion;

[0028] Figure 14 briefly shows Figure 12 Cross-sectional view of the groove portion. Detailed implementation mode

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description of the embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its application objects, or their uses.

[0030] Figure 1 shows the structure of the contact sensor 1 to which the conductive film 4 (refer to Figures 2 to 5 ) according to the embodiment of the present disclosure is applied. The contact sensor 1 is a sensor-type input device capable of performing touch operations. The contact sensor 1 is used, for example, as an input device for in-vehicle devices such as car navigation, display devices of personal computers, mobile phones, portable information terminals, portable game consoles, copiers, ticket vending machines, automated teller machines, watches, etc.

[0031] In the following description, the side where the operation surface 2a of the cover member 2 to be described later is located is defined as the "front side" of the contact sensor 1, and the opposite side is defined as the "back side" of the contact sensor 1, so as to define the positional relationship of the respective elements constituting the contact sensor 1. In addition, in the present embodiment, for the sake of convenience of explanation,Figures 1 to 5 The direction from the lower side to the upper side in the plane of the paper is defined as the first direction D1. On the other hand, Figures 1 to 5 the direction from the left side to the right side in the plane of the paper is defined as the second direction D2.

[0032] (Cover member)

[0033] As Figure 1 shown, the contact sensor 1 includes a cover member 2 having translucency. The cover member 2 is constituted by, for example, a glass cover sheet or a protective cover made of plastic. The cover member 2 is formed, for example, in a plate shape that is rectangular when viewed from above. The cover member 2 is fixed to the first surface 5a of a substrate 5 described later through an adhesive layer 21 described later (refer to Figure 6 and Figure 8 ).

[0034] As Figure 1 , Figure 6 and Figure 8 shown, on the cover member 2, a decorative portion 3 that is dark-colored such as black and has a substantially frame shape is formed by screen printing or the like on the peripheral portion of the back surface. The internal rectangular area surrounded by the decorative portion 3 becomes a visible area V that can transmit light. That is, the user can obtain visual information from a display panel (not shown) arranged on the back side of the contact sensor 1 via the visible area V. The front surface of the cover member 2 in the visible area V is configured as an operation surface 2a that is contacted by the user's finger F (refer to Figure 6 ) or the like along with a touch operation.

[0035] (Substrate)

[0036] As Figures 2 to 5 shown, the contact sensor 1 includes a substrate 5. The substrate 5 is formed in a substantially rectangular shape when viewed from above. As Figure 6 and Figure 8 shown, the substrate 5 has a first surface 5a and a second surface 5b. The substrate 5 is laminated and arranged on the cover member 2 such that the first surface 5a faces the back surface of the cover member 2 with the adhesive layer 21 described later interposed therebetween. It should be noted that in Figure 6 and Figure 8 , for the sake of simplifying the illustration, the illustration of a first groove forming layer 7 and a second groove forming layer 8 described later is omitted.

[0037] As Figure 11 and Figure 12 shown, the substrate 5 has a film base material 6. The film base material 6 is constituted by a resin material having transparency. As the resin material having transparency, for example, resin materials such as PET (polyethylene terephthalate), polycarbonate, COP (cycloolefin polymer), and COC (cycloolefin copolymer) can be cited.

[0038] The substrate 5 has a first groove forming layer 7 and a second groove forming layer 8. The first groove forming layer 7 and the second groove forming layer 8 are layers for forming groove portions 9, 9, ... described later, and are made of a resin material having insulating properties and transmissive properties.

[0039] The first groove forming layer 7 is laminated on the front side of the film base material 6. The front side of the first groove forming layer 7 faces the back side of the cover member 2. That is, the front side of the first groove forming layer 7 corresponds to the first surface 5a of the substrate 5. The thickness of the first groove forming layer 7 is, for example, 1.8 to 4.2 μm.

[0040] The second groove forming layer 8 is laminated and arranged on the back side of the film substrate 6. The back side of the second groove forming layer 8 faces the back side of the cover member 2 via the first groove forming layer 7 and the film substrate 6. That is, the back side of the second groove forming layer 8 corresponds to the second surface 5b of the substrate 5. The thickness of the second groove forming layer 8 is, for example, 1.8 to 4.2 μm.

[0041] like Figure 11 and Figure 12 As shown, a plurality of grooves 9, 9, ... are provided on the first surface 5a and the second surface 5b of the substrate 5. Each groove 9 extends linearly on the first surface 5a and the second surface 5b so as to form a predetermined pattern described later.

[0042] The groove portion 9 located on the first surface 5a is formed in the first groove forming layer 7 in a bottomed shape that is recessed from the first surface 5a toward the front surface of the film substrate 6 (see Figure 13 The grooves 9 located on the second surface 5b are formed in the second groove-forming layer 8 in a bottomed shape that is recessed from the second surface 5b toward the back surface of the film substrate 6. The depth of each groove 9 is set to, for example, 0.5 to 3.0 μm.

[0043] (Adhesive layer)

[0044] like Figure 6 and Figure 8 As shown, the touch sensor 1 includes adhesive layers 21, 21. Each adhesive layer 21 is stacked on the first surface 5a and the second surface 5b of the substrate 5. The adhesive layer 21 is an optically transparent adhesive (OCA) and preferably has a thickness of 25 to 250 μm.

[0045] The adhesive layer 21 has a notch 22 formed by cutting away a portion of the adhesive layer 21. Specifically, the adhesive layer 21 located on the first surface 5a side has the notch 22 formed therein so as to correspond to the mounting position of the first connection portion 18 described later relative to the first surface 5a. In addition, the adhesive layer 21 located on the second surface 5b side has the notch 22 formed therein so as to correspond to the mounting position of the second connection portion 19 described later relative to the second surface 5b.

[0046] (The first electrode and the second electrode)

[0047] As Figures 3 to 6 shown, the contact sensor 1 includes a plurality of first electrodes 11, 11,... and a plurality of second electrodes 12, 12,... based on the capacitance method.

[0048] The first electrodes 11, 11,... and the second electrodes 12, 12,... are arranged in the visible area V. In the contact sensor 1, it is possible to detect the touch operation of the user's finger F (that is, the detection object connected to the ground wire (GND)) that contacts the operation surface 2a of the cover member 2 through the first electrodes 11, 11,... and the second electrodes 12, 12,... located in the visible area V (refer to Figure 6 ).

[0049] As Figure 4 shown, each first electrode 11 is arranged on the first surface 5a of the substrate 5. On the other hand, as Figure 5 shown, each second electrode 12 is arranged on the second surface 5b of the substrate 5. That is, each second electrode 12 is in a state of being insulated from each first electrode 11 via the substrate 5.

[0050] As Figure 6 shown, each first electrode 11 is configured to receive the electric field E radiated from each second electrode 12 (refer to the double-dot dash line in Figure 6 ). That is, the first electrode 11 is configured as a receiving electrode.

[0051] As Figure 3 and Figure 4 shown, when viewed from above, each first electrode 11 extends in a substantially strip shape along the long side direction (second direction D2) of the substrate 5. The first electrodes 11, 11,... are arranged at intervals in the short side direction (first direction D1) of the substrate 5. Each first electrode 11 is connected to a detection circuit (not shown) via a flexible wiring board 16 described later.

[0052] As Figure 6 shown, each second electrode 12 is configured to be connected to a drive circuit (not shown) via a flexible wiring board 16 described later, and radiate an electric field E to the surroundings through the drive circuit. That is, each second electrode 12 is configured as a transmitting electrode.

[0053] As Figure 3 and Figure 5 shown, when viewed from above, each second electrode 12 extends in a substantially strip shape along the short side direction (first direction D1) of the substrate 5. The second electrodes 12, 12,... are arranged at intervals in the long side direction (second direction D2) of the substrate 5.

[0054] Each first electrode 11 and each second electrode 12 are composed of a plurality of thin lines 30, 30,.... Specifically, each first electrode 11 and each second electrode 12 are structured by arranging the thin lines 30, 30,... in a prescribed pattern on the first surface 5a and the second surface 5b of the substrate 5. As an example of the above-mentioned prescribed pattern, a first pattern (mesh pattern) in which the thin lines 30, 30,... are arranged in a grid shape can be cited (refer to Figure 7 ).

[0055] As Figure 7 shown, the first pattern is a mesh shape formed by the thin lines 30, 30,... crossing each other and being arranged at a prescribed interval (equal intervals in the illustrated example). That is, the first pattern becomes a mesh structure formed by regularly arranging a plurality of units composed of the thin lines 30, 30,.... Each of the above-mentioned units is formed as a parallelogram having the same size as each other.

[0056] Each thin line 30 constituting the first pattern extends in a direction inclined with respect to both the first direction D1 and the second direction D2. Each thin line 30 has a line width of several μm, for example. Specifically, in each first electrode 11 and each second electrode 12, in order to ensure the visibility of the visual recognition area V, it is preferable that the line width of each thin line 30 is set to 2 μm or less. It should be noted that the specific structure of the thin line 30 will be described later.

[0057] Here, as the above-mentioned prescribed pattern, it is not limited to the above-mentioned first pattern (mesh pattern). For example, it may also be a second pattern in which a plurality of thin lines 30, 30,... are arranged in a ladder shape, or a third pattern in which a plurality of thin lines 30, 30,... are arranged in a shape other than a grid shape and a ladder shape.

[0058] (First wiring portion and second wiring portion)

[0059] As Figures 3 to 5 shown, the contact sensor 1 includes a plurality of first wiring portions 13, 13,... and a plurality of second wiring portions 14, 14,.... The first wiring portions 13, 13,... and the second wiring portions 14, 14,... are elements for electrically connecting the first electrodes 11, 11,... and the second electrodes 12, 12,... to an external circuit (not shown).

[0060] The first wiring portions 13, 13,... and the second wiring portions 14, 14,... are arranged at the peripheral portion of the substrate 5 (that is, outside the visual recognition area V). Specifically, when viewed from above the operation surface 2a side, the first wiring portions 13, 13,... and the second wiring portions 14, 14,... are arranged at a position related to the decorative portion 3 (refer to Figure 1 and Figure 8)Overlapping positions. That is, the first wiring portions 13, 13, … and the second wiring portions 14, 14, … cannot be visually recognized from the operation surface 2a side due to the decoration portion 3. It should be noted that in Figure 6 the illustration of the first wiring portions 13, 13, … and the second wiring portions 14, 14, … is omitted for the sake of simplifying the illustration.

[0061] As Figure 4 and Figure 8 shown, each first wiring portion 13 is formed on the first surface 5a of the substrate 5. One end portion of each first wiring portion 13 is electrically connected to one end portion of each first electrode 11 (the end portion located on the left side of the paper surface of Figure 4 ). In addition, the other end portions of the first wiring portions 13, 13, … are arranged to converge substantially at the center in the long side direction of the substrate 5 on the lower side of the paper surface of the peripheral portion of the first surface 5a. Figure 4

[0062] A connection pad 15 for electrically connecting to a first connection portion 18 of a flexible wiring board 16 described later is provided at the other end portion of each first wiring portion 13. The other end portion of each first wiring portion 13 is configured to be electrically connected to the flexible wiring board 16 via each connection pad 15.

[0063] As Figure 5 and Figure 8 shown, each second wiring portion 14 is formed on the second surface 5b of the substrate 5. One end portion of each second wiring portion 14 is electrically connected to one end portion of each second electrode 12 (the end portion located on the lower side of the paper surface of Figure 5 ). In addition, the other end portions of the second wiring portions 14, 14, … extend in a manner of converging substantially at the center in the long side direction of the substrate 5 on the lower side of the paper surface of the peripheral portion of the second surface 5b. The other end portions of the second wiring portions 14, 14, … are arranged at intervals from the other end portions of the first wiring portions 13 in the long side direction (second direction D2) of the substrate 5. Figure 5

[0064] A connection pad 15 for electrically connecting to a second connection portion 19 of a flexible wiring board 16 described later is provided at the other end portion of each second wiring portion 14. The other end portion of each second wiring portion 14 is configured to be electrically connected to the flexible wiring board 16 via each connection pad 15.

[0065] Each first wiring portion 13, each second wiring portion 14, and each connection pad 15 are each configured by arranging a plurality of thin lines 30, 30, … in a predetermined pattern on the first surface 5a and the second surface 5b of the substrate 5, respectively. Specifically, each first wiring portion 13, each second wiring portion 14, and each connection pad 15 are each configured by a pattern (corresponding to the above-mentioned second pattern) formed by arranging the thin lines 30b, 30b, … in a ladder shape (refer toFigure 9 and Figure 10 ) It should be noted that, different from each of the first electrodes 11 and each of the second electrodes 12, each of the first wiring portions 13, each of the second wiring portions 14, and each of the connection pads 15 are preferably such that the line width of each of the fine lines 30 is set to 10 μm or less.

[0066] (Flexible wiring board)

[0067] As Figure 1 shown, the contact sensor 1 includes a flexible wiring board 16. The flexible wiring board 16 is configured to have flexibility and its electrical characteristics do not change even in a deformed state. The flexible wiring board 16 is formed of a flexible insulating film such as polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc.

[0068] As Figure 2 shown, the flexible wiring board 16 has a main body portion 17, a first connection portion 18, and a second connection portion 19. The first connection portion 18 and the second connection portion 19 are formed integrally with the main body portion 17, and the first connection portion 18 and the second connection portion 19 are formed to branch in two directions from one end side of the main body portion 17.

[0069] As Figure 8 shown, the first connection portion 18 is fixed, for example, to the peripheral portion of the first surface 5a by an anisotropic conductive adhesive (not shown). In this fixed state, the first connection portion 18 is electrically connected to the first wiring portions 13, 13,....

[0070] The second connection portion 19 is fixed to the peripheral portion of the second surface 5b by the above-mentioned anisotropic conductive adhesive. In this fixed state, the second connection portion 19 is electrically connected to the second wiring portions 14, 14,....

[0071] (Protective film)

[0072] As Figure 6 and Figure 8 shown, the contact sensor 1 includes a protective film 23. The protective film 23 is a film material mainly used to protect the second electrodes 12, 12,... and the second wiring portions 14, 14,.... As such a film material, for example, resin materials such as PET (polyethylene terephthalate), polycarbonate, COP (cycloolefin polymer), COC (cycloolefin copolymer), and PE can be cited.

[0073] The protective film 23 is formed, for example, to have a substantially rectangular shape in a top view and is formed to have the same size as the substrate 5. The protective film 23 is laminated and disposed at a position opposite to the second surface 5b of the substrate 5. Specifically, the protective film 23 is fixed to the second surface 5b of the substrate 5 through an adhesive layer 21.

[0074] (Fine wire)

[0075] As Figure 11 and Figure 12 shown, each fine wire 30 includes a conductive material embedded in each groove portion 9. Specifically, Figure 11 is a cross-sectional view of the fine wire 30 (specifically, Figure 7 the fine wire 30 in) that constitutes the first electrode 11 and the second electrode 12. Figure 12 is a cross-sectional view of the fine wire 30 (specifically, Figure 9 and Figure 10 the fine wire 30 in) that constitutes the first wiring portion 13, the second wiring portion 14, and the connection pad 15. It should be noted that in the following description, the fine wire 30 that constitutes the first electrode 11 and the second electrode 12 is sometimes referred to as the fine wire 30a, and the fine wire 30 that constitutes the first wiring portion 13, the second wiring portion 14, and the connection pad 15 is sometimes referred to as the fine wire 30b. In addition, the groove portion 9 in which the fine wire 30a is embedded is sometimes referred to as the groove portion 9a (first groove portion), and the groove portion 9 in which the fine wire 30b is embedded is sometimes referred to as the groove portion 9b (second groove portion).

[0076] As Figure 11 and Figure 12 shown, each fine wire 30 is composed of, for example, an adhesion layer 31, a conductive layer 32, and a blackening layer 38.

[0077] The adhesion layer 31 is an element for ensuring the adhesion of the conductive layer 32 to the groove portion 9. In addition, the adhesion layer 31 has a function of making the fine wire 30 difficult to be visually recognized when the user observes from the operation surface 2a of the contact sensor 1.

[0078] The adhesion layer 31 contains any one of transition metals in Groups 4 to 6, 10, and 11. The adhesion layer 31 is, for example, a metal layer composed of a metal nitride, a metal oxide, or a metal oxynitride containing both a metal nitride and a metal oxide, which contains at least one or more metals selected from the group consisting of Ti, V, W, Ta, Cr, Ag, Mo, Cu, Ni, and Nb. The adhesion layer 31 can be a single layer, or can also be a laminate formed by laminating a plurality of layers with different compositions. The adhesion layer 31 is laminated on the groove portion 9 in a thin film shape by, for example, evaporation or sputtering.

[0079] In addition, the close contact layer 31 includes a bottom surface portion 311 formed along the bottom surface of the groove portion 9 and a side surface portion 312 formed along the side surface of the groove portion 9. It should be noted that in the following description, the close contact layer 31 of the thin line 30a is sometimes referred to as the close contact layer 31a (first metal compound layer), and the close contact layer 31 of the thin line 30b is sometimes referred to as the close contact layer 31b (second metal compound layer). The bottom surface portion 311 of the close contact layer 31a is referred to as the bottom surface portion 311a (third layer), and the side surface portion 312 of the close contact layer 31a is referred to as the side surface portion 312a (first layer). The bottom surface portion 311 of the close contact layer 31b is referred to as the bottom surface portion 311b, and the side surface portion 312 of the close contact layer 31b is referred to as the side surface portion 312b (second layer).

[0080] The conductive layer 32 is an element for ensuring the conductivity of the thin line 30. In the present embodiment, the conductive layer 32 is composed of a seed layer 33 and a main body layer 34. Both the seed layer 33 and the main body layer 34 are composed of a conductive material. A conductive metal such as copper (Cu) or silver (Ag) is suitably used as the conductive material. It should be noted that a transparent conductive material having light transmissivity such as a conductive resin material, indium tin oxide, or tin oxide may be used instead of the above-mentioned conductive metal. It should be noted that in the following description, the conductive layer 32 of the thin line 30a is sometimes referred to as the conductive layer 32a (first conductive layer), and the conductive layer 32 of the thin line 30b is sometimes referred to as the conductive layer 32b (second conductive layer).

[0081] The seed layer 33 has a function of improving the close contact property between the close contact layer 31 and the main body layer 34. Specifically, for example, in the electroplating process for forming the main body layer 34, the seed layer 33 functions as a cathode for depositing a plating solution such as copper (Cu) on the close contact layer 31. The seed layer 33 is laminated in a thin film form on the close contact layer 31 by, for example, evaporation or sputtering. It should be noted that when the main body layer 34 is formed by a method different from the electroplating process, the seed layer 33 may not be provided.

[0082] The main body layer 34 is formed by, for example, evaporation, sputtering, electroless plating treatment, or electroplating treatment. In the present embodiment, a method of laminating the main body layer 34 on the seed layer 33 by electroplating treatment is shown. It should be noted that after the electroplating treatment, the seed layer 33 and the main body layer 34 are formed as one body, and the interface between the seed layer 33 and the main body layer 34 is in a state where it cannot be discriminated.

[0083] The blackening layer 38 has a function of making it difficult for the thin line 30 to be visually recognized when the user observes from the operation surface 2a of the contact sensor 1. The blackening layer 38 is provided on the upper layer side of each of the close contact layer 31 and the conductive layer 32.

[0084] (Groove portion)

[0085] As Figure 13and Figure 14 As shown in Figure 14 , groove portions 9 are formed on the first surface 5a and the second surface 5b of the substrate 5. Fine wires 30 are embedded in the groove portions 9.

[0086] The groove portion 9 is composed of a bottom surface 91 extending in the width direction (the left - right direction in the drawing) and side surfaces 92 connecting the bottom surface 91 and the opening of the groove portion 9. It should be noted that in the following description, the bottom surface 91 of the groove portion 9a may sometimes be referred to as the bottom surface 91a (the first bottom), and the side surface 92 of the groove portion 9a may sometimes be referred to as the side surface 92a (the first side portion). The bottom surface 91 of the groove portion 9b may sometimes be referred to as the bottom surface 91b (the second bottom), and the side surface 92 of the groove portion 9b may sometimes be referred to as the side surface 92b (the second side portion).

[0087] Here, the angle formed by the bottom surface 91a and the side surface 92a of the groove portion 9a is set as the angle C1 (the first angle), and the angle formed by the bottom surface 91b and the side surface 92b of the groove portion 9b is set as the angle C2 (the second angle). In addition, the thickness of the side surface portion 312a of the adhesion layer 31a in the fine wire 30a formed along the side surface 92a of the groove portion 9a is set as the thickness L1 (the first thickness), and the thickness of the side surface portion 312b of the adhesion layer 31b in the fine wire 30b formed along the side surface 92b of the groove portion 9b is set as the thickness L2 (the second thickness). At this time, when the angle C1 is smaller than the angle C2, the thickness L1 is thinner than the thickness L2.

[0088] It should be noted that the thickness L1 is, for example, the thickness of the adhesion layer 31a at a position where the depth from the bottom surface 91a of the groove portion 9a is the depth A2 in the depth direction. When the depth of the groove portion 9a (the distance from the bottom 91a to the opening) is set as A1, the depth A2 is 2 / 3 of the depth A1. Similarly, the thickness L2 is, for example, the thickness of the adhesion layer 31b at a position where the depth from the bottom surface 91b of the groove portion 9b is the depth A4 in the depth direction. When the depth of the groove portion 9b (the distance from the bottom 91b to the opening) is set as A3, the depth A4 is 2 / 3 of the depth A3.

[0089] In addition, the angles C1 and C2 are each 90° or more and 135° or less. The thicknesses L1 and L2 are each 3 nm or more and 150 nm or less.

[0090] In addition, the thickness L1 of the bottom surface portion 311a of the adhesion layer 31a in the fine wire 30a and the thickness L2 of the bottom surface portion 311b of the adhesion layer 31b in the fine wire 30b are 5 nm or more and 150 nm or less.

[0091] In addition, the length in the width direction of the bottom surface portion 311a of the groove portion 9a is set as the length W1 (the first length), and the length in the width direction of the bottom surface portion 311b of the groove portion 9b is set as the length W2 (the second length). At this time, it is preferably configured such that the length W1 is smaller than the length W2 and the angle C1 is smaller than the angle C2.

[0092] In addition, the ratio of thickness T1 to thickness L1 is 1 or more and 1.75 or less. The ratio of thickness T2 to thickness L2 is 1 or more and 1.75 or less.

[0093] (Process of forming groove portion and fine wire)

[0094] Next, the process of forming the groove portion 9 and the fine wire 30 will be described. In the following forming process, only the groove portion 9 (9a) located in the first groove formation layer 7 and the fine wire 30 (30a) constituting the first electrode 11 will be described.

[0095] First, the groove portion 9 is formed in the first groove formation layer 7. Next, a metal layer composed of the above-mentioned metal nitride, metal oxide, or metal oxynitride containing both metal nitride and metal oxide is formed in a thin film shape on the first surface 5a and the groove portion 9 by evaporation or sputtering. Through this film formation process, the adhesion layer 31 is formed in the groove portion 9.

[0096] After forming the adhesion layer 31, for example, copper (Cu) is formed in a thin film shape on the adhesion layer 31 by evaporation or sputtering. Through this film formation process, the seed layer 33 is formed in the groove portion 9.

[0097] After forming the seed layer 33, through, for example, electroplating treatment and using the seed layer 33 as the cathode, a conductive metal such as copper (Cu) is laminated over the entire area of the seed layer 33.

[0098] After laminating a predetermined amount of copper by electroplating treatment, the excess copper laminated on the first surface 5a is gradually removed. Thereby, the main body layer 34 is formed in the groove portion 9.

[0099] After forming the main body layer 34, a blackening layer 38 is formed by performing a blackening treatment. Finally, an anti-rust treatment for forming an anti-rust film (not shown) is performed on the blackening layer 38.

[0100] Through the above processes, the groove portion 9 and the fine wire 30 are formed.

[0101] It should be noted that in the present embodiment, the groove portion 9 located in the second groove formation layer 8 is formed by the same process as the process of forming the groove portion 9 located in the first groove formation layer 7. In addition, the fine wires 30 constituting the second electrode 12, the first wiring portion 13, the second wiring portion 14, and the connection pad 15 are formed by the same process as the process of forming the fine wire 30 constituting the first electrode 11.

[0102] [Function and effect of the embodiment]

[0103] As described above, a groove portion 9a (first groove portion) and a groove portion 9b (second groove portion) extending linearly are formed on the first surface 5a of the substrate 5. A thin wire 30a is buried in the groove portion 9a. A thin wire 30b is buried in the groove portion 9b. Specifically, in the groove portion 9a, a conductive layer 32a (first conductive layer) composed of a metal is buried via a close-contact layer 31a (first metal compound layer) composed of a metal compound. In the groove portion 9b, a conductive layer 32b (second conductive layer) composed of a metal is buried via a close-contact layer 31b (second metal compound layer) composed of a metal compound. The groove portion 9a includes a bottom surface 91a (first bottom) and a side surface 92a (first side portion) connecting the bottom surface 91a and the opening of the groove portion 9a. The groove portion 9b includes a bottom surface 91b (second bottom) and a side surface 92b (second side portion) connecting the bottom surface 91b and the opening of the groove portion 9b.

[0104] Here, the angle formed by the bottom surface 91a and the side surface 92a of the groove portion 9a is set to angle C1 (first angle), and the angle formed by the bottom surface 91b and the side surface 92b of the groove portion 9b is set to angle C2 (second angle). In addition, the thickness of the side surface 312b of the close-contact layer 31 in the thin line 30a formed along the side surface 92a of the groove portion 9a is set to thickness L1 (first thickness), and the thickness of the side surface 312b of the close-contact layer 31 in the thin line 30b formed along the side surface 92b of the groove portion 9b is set to thickness L2 (second thickness). At this time, when the angle C1 is smaller than the angle C2, the thickness L1 is smaller than the thickness L2.

[0105] As described above, the thin wires 30a and 30b include the conductive layer 32 made of metal and the adhesion layer 31 made of a metal compound. The conductive layer 32 is buried in the groove 9 via the adhesion layer 31 formed in a thin film on the groove 9. The conductive layer 32 has adhesion to the groove 9 secured by the adhesion layer 31.

[0106] However, for example, when a current flows through the conductive layer 32, the temperature inside the conductive layer 32 and the adhesive layer 31 may rise due to the heat of the conductive layer 32 and the adhesive layer 31. Since the conductive layer 32 is made of metal and the adhesive layer 31 is made of a metal compound, if the temperature inside the conductive layer 32 and the adhesive layer 31 rises, the volume of the conductive layer 32 expands more than the volume of the adhesive layer 31. For example, the linear expansion coefficient of Cu is 17.7×10 －6 K, the linear expansion coefficient of ceramics (metal nitrides) is 1 to 10×10 －6 K. Therefore, the adhesion layer 31 is compressed due to the expansion of the conductive layer 32. In particular, when the groove portion 9 is formed in a concave bottomed shape, the side portions 312 of the groove portion 9 are formed opposite to each other, so the adhesion layer 31 formed along the side of the groove portion 9 (specifically, the side portions 312 of the adhesion layer 31) is compressed.

[0107] In addition, when the adhesion layer 31 is made of a metal compound, the thicker the film thickness of the adhesion layer 31, the higher the rigidity of the adhesion layer 31, and the easier it is to generate stress relative to the expansion of the conductive layer 32 within the conductive layer 32, resulting in the destruction of the adhesion layer 31.

[0108] More specifically, the stress generated due to the expansion of the conductive layer 32 and relative to the depth direction of the groove portion 9 ( Figure 11 and Figure 12 the up-and-down direction of the drawing) is applied to the bottom surface portion 311 of the adhesion layer 31, and the stress relative to the width direction of the groove portion 9 ( Figure 11 and Figure 12 the left-and-right direction of the drawing) is applied to the side surface portion 312 of the adhesion layer 31. At this time, since an opening is provided at a position of the groove portion 9 opposite to the bottom surface portion 311 of the adhesion layer 31, the stress applied to the bottom surface portion 311 of the adhesion layer 31 does not increase, and thus it is difficult to cause the destruction of the adhesion layer 31. In contrast, since the side surface portions 312 of the adhesion layer 31 are respectively formed on the side surfaces 92 on both sides of the groove portion 9, the stress relative to the width direction of the groove portion 9 is applied. In particular, if the angle formed by the bottom surface 91 and the side surface 92 of the groove portion 9 becomes smaller, the angle between the stress relative to the width direction of the groove portion 9 and the side surface 92 (the side surface portion 312 of the adhesion layer 31) approaches perpendicular, and thus the influence of the stress caused by the expansion of the conductive layer 32 on the adhesion layer 31 becomes larger.

[0109] Therefore, in the present embodiment, the thickness of the side surface portion 312 of the adhesion layer 31 formed along the side surface 92 of the groove portion 9 is changed according to the angle formed by the bottom surface 91 and the side surface 92 of the groove portion 9. Specifically, in the groove portion 9a where the angle C1 formed by the bottom surface 91a and the side surface 92a is small, the thickness L1 of the side surface portion 312b of the adhesion layer 31a in the fine wire 30a is made smaller. By reducing the thickness L1 according to the angle C1, the side surface portion 312 of the adhesion layer 31 can be easily flexed, and thus the influence of the stress caused by the expansion of the conductive layer 32 can be suppressed. Thereby, the destruction of the adhesion layer 31 can be suppressed. Therefore, the conductive film can be made into a structure resistant to external disturbances such as temperature changes and erosion.

[0110] In addition, the angles C1 and C2 are 90° or more and 135° or less. The thicknesses L1 and L2 are 3 nm or more and 150 nm or less. Thus, the thickness of the adhesion layer 31 becomes thinner, so that the concentration of stress at the corner portion of the adhesion layer 31 can be suppressed, and thus the reduction in the adhesion between the adhesion layer 31 and the groove portion 9 can be suppressed.

[0111] In addition, the intimate layer 31 contains transition metals of at least any one of Groups 4 to 6, Group 10, and Group 11. Thereby, the chemical resistance of the intimate layer 31 is improved, and the intimate layer 31 is difficult to be visually recognized from the outside.

[0112] In addition, the intimate layer 31 particularly preferably contains nitrogen. By nitriding the intimate layer 31, the reflectivity of the intimate layer 31 can be reduced, and thus the intimate layer 31 is difficult to be visually recognized from the outside.

[0113] In addition, the intimate layer 31a includes a bottom surface portion 311a (third layer) formed along the bottom surface 91a of the groove portion 9a. The thickness T1 of the bottom surface portion 311a is 5 nm or more and 150 nm or less. Therefore, the intimate layer 31a is difficult to be visually recognized from the outside.

[0114] In addition, it is preferable that the length W1 (first length) in the width direction of the groove portion 9a is smaller than the length W2 (second length) in the width direction of the groove portion 9b, and the angle C1 is smaller than the angle C2. When the length in the width direction of the groove portion 9 is small, the visual recognition degree of the intimate layer 31 can be reduced, but the adhesion between the intimate layer 31 and the groove portion 9 is reduced. Therefore, by making the angle between the bottom surface and the side surface of the groove portion 9 smaller, the thickness of the side surface portion 312 of the intimate layer 31 can be thinned, and the adhesion between the intimate layer 31 and the groove portion 9 can be improved.

[0115] In addition, the thickness T1 (third thickness) / thickness L1 is 1 or more and 1.75 or less. Thereby, excessive film stress on the intimate layer 31 is suppressed.

[0116] [Other Embodiments]

[0117] In the above embodiment, the first direction D1 and the second direction D2 are defined as Figures 1 to 5 the directions shown, but are not limited to such directions. For example, the direction from left to right in the plane of each figure may be defined as the first direction D1, and on the other hand, the direction from bottom to top in the plane of each figure may be defined as the second direction D2. That is, it may also be a structure in which each first electrode 11 extends along the length direction of the substrate 5, and on the other hand, each second electrode 12 extends along the short side direction of the substrate 5.

[0118] In addition, in the above embodiment, a mode of using a single substrate 5 is shown, but is not limited to this mode. For example, the substrate 5 may also be a laminate formed by laminating two base materials.

[0119] In addition, in the above-described embodiment, a method of forming electrodes (first electrode 11 and second electrode 12) on two surfaces (first surface 5a and second surface 5b) of a single substrate 5 is shown, but it is not limited to this method. That is to say, it may also be a method of forming the first electrode 11 and the second electrode 12 only on one side (either the first surface 5a or the second surface 5b) of a single substrate 5.

[0120] In addition, in the above-described embodiment, a method of applying a rectangular visual region V is shown, but it is not limited to this method. The visual region V may also be substantially circular, for example.

[0121] In addition, in the above-described embodiment, a method in which each of the first electrodes 11 and each of the second electrodes 12 are substantially strip-shaped is shown, but it is not limited to this method. For example, each of the second electrodes 12 may also be a method in which protrusions (not shown) are repeatedly arranged along the extending direction, where the middle part of the protrusion tapers at the front end as it approaches the second direction D2 or its opposite direction. Similarly, for each of the first electrodes 11, instead of the substantially strip-shaped method shown in the above-described embodiment, a method in which protrusions (not shown) are repeatedly arranged along the extending direction may be used, where the middle part of the protrusion tapers at the front end as it approaches the first direction D1 or its opposite direction. In other words, the shape of each electrode may also be a shape formed by repeating a shaped pad portion such as a rhombus along the extending direction.

[0122] In addition, in the present embodiment, a rounded corner may be formed at the corner between the bottom surface 91 and the side surface 92 of the groove portion 9. In addition, the side surface 92 of the groove portion 9 may also be inclined in such a way that it gradually expands as it approaches the opening from the bottom surface 91 of the groove portion 9.

[0123] In addition, in the present embodiment, the cross-section of at least either the bottom surface 91 or the side surface 92 of the groove portion 9 may also be arc-shaped. In this case, the angle C1 is the angle formed by the tangent at the deepest part of the bottom surface 91a in the groove portion 9a and the tangent of the side surface 92a (for example, Figure 11 the tangent at the position of the depth A2). In addition, the angle C2 may also be the angle formed by the tangent at the deepest part of the bottom surface 91b in the groove portion 9b and the tangent of the side surface 92b (for example, Figure 12 the tangent at the position of the depth A4).

[0124] In addition, in the present embodiment, the case where the groove portion 9 includes the groove portion 9a with an angle C1 formed by the bottom surface 91a and the side surface 92a, and the groove portion 9b with an angle C2 formed by the bottom surface 91b and the side surface 92b is taken as an example for explanation. That is to say, in the present embodiment, the case where the groove portion 9 includes two groove portions with unequal angles formed by the bottom surface and the side surface is taken as an example for explanation, but it is not limited thereto. For example, the groove portion 9 may also include three or more groove portions with unequal angles formed by the bottom surface and the side surface.

[0125] In addition, in the present embodiment, the blackening layer 38 may also be omitted.

[0126] In the above embodiment, the capacitive sensor 1 to which the conductive film 4 according to the embodiment of the present disclosure is applied is exemplified, but it is not limited thereto. For example, the conductive film 4 according to the embodiment of the present disclosure can be widely applied to technical fields other than the capacitive sensor 1 (for example, various technical fields such as liquid crystal display devices, organic electroluminescence display devices (OLEDs), micro-LED display devices, solar cell devices, heater devices, antenna devices, electromagnetic wave shielding sheets, etc.).

[0127] The above has described the embodiments of the present disclosure, but the present disclosure is not limited to the above embodiments, and various modifications can be made within the scope of the present disclosure.

[0128] -Industrial Applicability-

[0129] The present disclosure can be industrially used as a conductive film applicable to capacitive sensors and the like.

[0130] -Symbol Explanation-

[0131] 1: Capacitive sensor

[0132] 2: Cover member

[0133] 3: Decorative portion

[0134] 4: Operating surface

[0135] 5: Substrate

[0136] 5a: First surface

[0137] 5b: Second surface

[0138] 6: Film base material

[0139] 7: First groove forming layer

[0140] 8: Second groove forming layer

[0141] 9: Groove portion

[0142] 9a: Groove portion (first groove portion)

[0143] 9b: Groove portion (second groove portion)

[0144] 91: Bottom surface

[0145] 91a: Bottom surface (first bottom portion)

[0146] 91b: Bottom surface (second bottom portion)

[0147] 92: Side surface

[0148] 92a: Side surface (first side portion)

[0149] 92b: Side surface (first side portion)

[0150] 11: First electrode

[0151] 12: Second electrode

[0152] 13: First wiring portion

[0153] 14: Second wiring portion

[0154] 15: Connection pad

[0155] 16: Flexible wiring board

[0156] 17: Main body portion

[0157] 18: First connection portion

[0158] 19: Second connection portion

[0159] 21: Adhesive layer

[0160] 22: Notch portion

[0161] 23: Protective film

[0162] 30: Fine wire

[0163] 30a: Fine wire

[0164] 30b: Fine wire

[0165] 31: Close contact layer

[0166] 31a: Close contact layer (first metal compound layer)

[0167] 31b: Close contact layer (second metal compound layer)

[0168] 311: Bottom surface portion

[0169] 311a: Bottom surface portion (third layer)

[0170] 312a: Bottom surface portion

[0171] 312: Side surface portion

[0172] 312a: Side face (first layer)

[0173] 312b: Side face (second layer)

[0174] 32: Conductive layer

[0175] 32a: Conductive layer (first conductive layer)

[0176] 32b: Conductive layer (second conductive layer)

[0177] 33: Seed layer

[0178] 34: Body layer

[0179] 38: Blackening layer

[0180] V: Visible area

[0181] C1: Angle (first angle)

[0182] C2: Angle (second angle)

[0183] L1: Thickness (first thickness)

[0184] L2: Thickness (second thickness)

[0185] T1: Thickness (third thickness)

[0186] T2: Thickness

[0187] W1: Length (first length)

[0188] W2: Length (second length)

Claims

1. A conductive film, characterized in that: the conductive film includes a substrate having a first surface, a bottomed first groove portion and a second groove portion extending linearly are provided on the first surface of the substrate, in the first groove portion, a first conductive layer made of metal is embedded with a first metal compound layer made of a metal compound interposed therebetween, in the second groove portion, a second conductive layer made of metal is embedded with a second metal compound layer made of a metal compound interposed therebetween, the first groove portion includes a first bottom portion and a first side portion, and the first side portion connects the first bottom portion and the opening of the first groove portion, the second groove portion includes a second bottom portion and a second side portion, and the second side portion connects the second bottom portion and the opening of the second groove portion, the first metal compound layer includes a first layer formed along the first side portion, the second metal compound layer includes a second layer formed along the second side portion, when the first angle formed by the first bottom portion and the first side portion, i.e., the first angle, is smaller than the second angle formed by the second bottom portion and the second side portion, i.e., the second angle, the thickness of the first layer, i.e., the first thickness, is smaller than the thickness of the second layer, i.e., the second thickness.

2. The conductive film according to claim 1, characterized in that: the first angle is 90° or more and 135° or less, the first thickness is 3 nm or more and 150 nm or less.

3. The conductive film according to claim 1, characterized in that: the first metal compound layer includes at least any one group of transition metals among the transition metals of Group 4 to Group 6, Group 10, and Group 11.

4. The conductive film according to claim 1, characterized in that: the first metal compound layer includes nitrogen.

5. The conductive film according to claim 1, characterized in that: the first metal compound layer includes a third layer formed along the first bottom portion, the thickness of the third layer is 5 nm or more and 150 nm or less.

6. The conductive film according to claim 1, characterized in that: when the length in the width direction of the first groove portion, i.e., the first length, is smaller than the length in the width direction of the second groove portion, i.e., the second length, the first angle is smaller than the second angle.

7. The conductive film according to claim 1, characterized in that: the first metal compound layer includes a third layer formed along the first bottom portion, when the first thickness is set as T1 and the thickness of the third layer, i.e., the third thickness, is set as L1, L1 / T1 is 1 or more and 1.75 or less.

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