Capacitive sensor and input device

Abstract

The capacitive sensor of the present invention that takes processability, environmental resistance into consideration and can provide invisibility has the following structure: a first transparent electrode portion (4) and a second transparent electrode portion (5), both of which are formed of crystalline ITO, are formed in a pattern and provided on a substrate (2), and a bridging wiring portion (10) formed of amorphous IZO is provided with an insulating layer (20) interposed therebetween on the adjacent first transparent electrode portion (4) and a connecting portion (7) continuous therewith, and two adjacent second transparent electrode portions (5) are electrically connected through the bridging wiring portion (10). When the thickness of the second transparent electrode portion 5 is TE and the thickness of the bridging wiring portion 10 is TB, the following formula (1) and the following formula (2) are satisfied: 0.28×TE + 83 nm ≤ TB ≤ 0.69×TE + 105 nm (1); 30 nm ≤ TE ≤ 50 nm (2).

Description

Technical Field

[0001] The present invention relates to a capacitive sensor and an input device including the related capacitive sensor. Background Art

[0002] In Patent Document 1, a capacitive sensor is disclosed, which is characterized by including: a substrate having translucency; a plurality of first transparent electrodes arranged and disposed along a first direction in a detection region on one main surface of the substrate and having translucency; a plurality of second transparent electrodes arranged and disposed along a second direction intersecting the first direction in the detection region and having translucency, including conductive nanowires; a connection part provided integrally with the first transparent electrode for electrically connecting two adjacent first transparent electrodes to each other; a bridging wiring part provided separately from the second transparent electrode for electrically connecting two adjacent second transparent electrodes to each other and including an amorphous oxide-based material; and a covering layer provided to cover the second transparent electrode and the bridging wiring part, the refractive index of the covering layer being higher than that of the second transparent electrode and lower than that of the bridging wiring part.

[0003] In Patent Document 2, there is a description of a case where the transparent electrode is formed of ITO and the bridging wiring part has a laminated structure including IZO (particularly, paragraph 0042, Figure 4 ). In Patent Document 3, it is described that when a bridging wiring part is prepared using a transparent conductive oxide (TCO), the thickness thereof can be prepared to be 5 nm or more and 70 nm or less (particularly, paragraph 0044).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2018 / 066214

[0007] Patent Document 2: JP-A-2015-118537

[0008] Patent Document 3: JP-A-2015-529899 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In the capacitive sensor disclosed in Patent Document 1, an insulating layer is disposed between the bridging wiring part and the first transparent electrode so that the bridging wiring part can maintain an insulated state from the first transparent electrode. Therefore, even if amorphous IZO with excellent translucency is used as the material of the bridging wiring part, the structure in the vicinity of the bridging wiring part becomes more complex than other parts and is easily visually recognized.

[0011] An object of the present invention is to provide a capacitive sensor and an input device including the related capacitive sensor, which can consider the processability and environmental resistance of a bridging wiring portion and improve the invisibility of a region including the bridging wiring portion when amorphous IZO is used as a material of the bridging wiring portion, and crystalline ITO is used as a material of a transparent electrode electrically connected to the bridging wiring portion and a transparent electrode laminated with the bridging wiring portion via an insulating layer.

[0012] Means for Solving the Problem

[0013] In one aspect, the present invention for solving the above problems is a capacitive sensor, characterized by including: a substrate having light transmissivity; a first transparent electrode including a plurality of first transparent electrode portions arranged along a first direction of the substrate and having light transmissivity, and a connecting portion integrally provided with the first transparent electrode portions and electrically connecting two adjacent first transparent electrode portions to each other; a second transparent electrode including a plurality of second transparent electrode portions arranged along a second direction intersecting the first direction of the substrate and having light transmissivity, and a bridging wiring portion provided separately from the second transparent electrode portions and electrically connecting two adjacent second transparent electrode portions to each other; and an insulating layer formed between the first transparent electrode and the bridging wiring portion, wherein the second transparent electrode portions are formed of crystalline ITO, the bridging wiring portion is formed of amorphous IZO, and when the thickness of the second transparent electrode portions is TE and the thickness of the bridging wiring portion is TB, the following formula (1) and the following formula (2) are satisfied:

[0014] 0.28×TE + 83 nm ≤ TB ≤ 0.69×TE + 105 nm (1)

[0015] 30 nm ≤ TE ≤ 50 nm (2).

[0016] The capacitive sensor in which the thickness TE of the second transparent electrode portions and the thickness TB of the bridging wiring portion are within the ranges represented by the above two formulas has excellent environmental resistance, excellent processability (selective etching property), and excellent invisibility. In particular, the closer to TB = 0.54×TE + 93 nm, the easier it is to obtain good invisibility.

[0017] In the above capacitive sensor, the substrate has a resin film, and the transparent electrode (second transparent electrode portion) of crystalline ITO provided on the substrate is formed by performing crystallization heat treatment or the like on amorphous ITO, and good invisibility is also achieved.

[0018] In the above-described capacitive sensor, the first transparent electrode may be formed of crystalline ITO. In this case, the thickness of the first transparent electrode is equal to the thickness of the second transparent electrode portion, and the first transparent electrode and the bridging wiring cross each other with the insulating layer therebetween, achieving good invisibility as well.

[0019] In the above-described capacitive sensor, when the insulating layer is made of a resin-based material with a refractive index of 1.5 or more and 2.0 or less, particularly good invisibility is achieved.

[0020] As another aspect of the present invention, there is provided an input device characterized by including the above-described capacitive sensor; and a light source provided on the substrate side of the capacitive sensor. The light source may be an organic EL light-emitting element. The light source is composed of an aggregate of a plurality of light-emitting bodies, and the arrangement pitch of the plurality of light-emitting bodies is 20 μm or less.

[0021] Advantages of the Invention

[0022] According to the present invention, there are provided a capacitive sensor with excellent environmental resistance, excellent processability (selective etching property), and excellent invisibility, and an input device including the related capacitive sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a plan view showing a capacitive sensor according to an embodiment of the present invention.

[0024] Figure 2 is a Figure 1 plan view showing an enlarged area A1 shown in.

[0025] Figure 3 is a Figure 2 cross-sectional view taken along a cut surface C1-C1 shown in.

[0026] Figure 4 is a Figure 2 cross-sectional view taken along a cut surface C2-C2 shown in.

[0027] Figure 5 is a diagram showing the results of confirming the influence of the etching residue of the constituent material of the bridging wiring portion on the first transparent electrode portion and the second transparent electrode portion formed of crystalline ITO by an etching solution for amorphous IZO.

[0028] Figure 6Fig. (a) is a graph of spectral data of the spectral photometric data Sw(λ) of white light of the organic EL light-emitting element, Fig. (b) is a graph of spectral data of the spectral photometric data Sg(λ) of green light of the organic EL light-emitting element, and Fig. (c) is a graph of the three stimulus values x(λ), y(λ), and z(λ) of the color matching function of the XYZ colorimetric system.

[0029] Figure 7 is a graph showing the influence of the electrode thickness TE and the bridging thickness TB on the color difference ΔE in the case of using white light as the light source.

[0030] Figure 8 is a graph showing the relationship between the electrode thickness TE and the bridging thickness TB and the change rate R related to the color difference ΔE in the case of using white light as the light source.

[0031] Figure 9 is a graph showing the influence of the light source on the relationship between the electrode thickness TE and the bridging thickness TB and the change rate R related to the color difference ΔE.

[0032] Figure 10 is a graph showing the relationship between the bridging thickness TB and the change rate R at different electrode thicknesses TE in the case of using white light as the light source.

[0033] Figure 11 is a graph showing the relationship between the electrode thickness TE and the bridging thickness TB when the change rate R becomes 0% or 50%.

[0034] Figure 12 is a graph conceptually showing the structure of the test structure observed.

[0035] Figure 13 is a graph showing the observed images in the case where the light source is white and green for three types of test structures.

[0036] Figure 14 is an explanatory diagram of an input device according to an embodiment of the present invention. Detailed Embodiment

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are assigned to the same components, and the description of the components that have been described once will be appropriately omitted.

[0038] Figure 1 is a top view showing the capacitive sensor 1 according to this embodiment. Figure 2 is to Figure 1 the enlarged top view of the region A1 shown in Figure 3 is Figure 2 the cross-sectional view at the cut surface C1-C1 shown inFigure 4 is Figure 2 a sectional view taken along the cut surface C2-C2 shown in Figure 4 . In addition, although the transparent electrode is transparent and thus cannot be visually recognized in principle, its outer shape is shown in Figure 1 and Figure 2 for easy understanding. Figure 1 and Figure 2 for easy understanding.

[0039] In the present application specification, the terms "transparent" and "translucency" refer to a state where the visible light transmittance is 50% or more (preferably 80% or more). Further, a haze value of 6% or less is suitable. In the present application specification, the terms "light-shielding" and "light-shielding property" refer to a state where the visible light transmittance is less than 50% (preferably less than 20%).

[0040] As Figures 1 to 4 shown in Figures 1 to 4 , the capacitive sensor 1 according to the present embodiment includes an insulating base material 2, a conductive first transparent electrode portion 4, a conductive second transparent electrode portion 5, a conductive connecting portion 7, a conductive bridging wiring portion 10, and an insulating cover layer 3. An insulating portion 21 is provided between the first transparent electrode portion 4 and the second transparent electrode portion 5, and the first transparent electrode portion 4 and the second transparent electrode portion 5 are electrically insulated from each other. From the perspective of the bridging wiring portion 10, the cover layer 3 is provided on the side opposite to the base material 2. An insulating optically transparent adhesive layer (OCA; Optical Clear Adhesive) 30 is provided between the base material 2 and the cover layer 3. The insulating portion 21 is buried between the base material 2 and the bridging wiring portion 10, and an insulating layer 20 is provided to cover the connecting portion 7 located between the bridging wiring portion 10 and the base material 2. As Figure 3 shown in Figure 3 , in the portion where the bridging wiring portion 10 is provided, the optically transparent adhesive layer 30 is provided between the bridging wiring portion 10 and the cover layer 3.

[0041] The base material 2 has light transmissibility and is formed of a resin-based base material such as a resin film containing polyethylene terephthalate (PET), polyolefin-based polymer (COC; Cyclic Olefin Copolymer, COP; Cyclic Olefin Polymer), polycarbonate (PC), etc., a glass base material, or the like. Since the heat resistance of the resin-based base material is generally about 150°C, when the resin-based base material is used as the base material 2, the heat treatment temperature of the member laminated thereon is also approximately 150°C as the upper limit. The refractive index of the base material 2 is not particularly limited, but when the base material 2 is composed of a resin-based base material, the refractive index of the base material 2 may be in the range of 1.4 to 1.6. In addition, there is a case where a refractive index adjustment layer (refractive index matching layer) is provided on the base material 2. The refractive index adjustment layer has a function of suppressing the following situation: between the laminated structure composed of the base material 2 and the transparent conductive material (the first transparent electrode portion 4 and the second transparent electrode portion 5) provided on the base material 2, the invisibility of the portion provided with the transparent conductive material due to interference is reduced. In the following description, the results of studying the invisibility between the laminated structure composed of the base material 2 and the transparent conductive material (the first transparent electrode portion 4 and the second transparent electrode portion 5) provided on the base material 2, and the structure in which the insulating layer 20 and the bridging wiring portion 10 are further laminated on the laminated structure are shown, and whether providing the refractive index adjustment layer on the base material 2 will affect the invisibility.

[0042] The first transparent electrode portion 4 and the second transparent electrode portion 5 are provided on one main surface of the base material 2 (the main surface on the Z1 side among the main surfaces of the base material 2 having the direction along the Z1-Z2 direction as the normal line, hereinafter referred to as "front surface 2a"). Details thereof will be described later. As Figure 3 characterized in, the cover layer 3 is provided on the side opposite to the base material 2 when viewed from the bridging wiring portion 10 and has light transmissibility. Examples of the material of the cover layer 3 include resin-based base materials such as polyethylene terephthalate (PET), polyolefin-based polymer (COC, COP), polycarbonate (PC), polymethyl methacrylate (PMMA; Polymethylmethacrylate), and glass base materials. A hard coat in which light-transmissive inorganic fine particles (e.g., zirconia, titanium oxide) are dispersed in a resin matrix can be provided on the resin-based base material.

[0043] As Figure 1As characterized in [description], the electrostatic capacitance type sensor 1, when viewed from the direction (Z1-Z2 direction) along the normal line of the surface on the side of the cover layer 3, is composed of a detection region 11 and a non-detection region 25. The detection region 11 is a region that can be operated by an operating body such as a finger, and the non-detection region 25 is a frame-shaped region located on the outer peripheral side of the detection region 11. The non-detection region 25 is shielded from light by a decorative layer (not shown), and light from the surface on the side of the cover layer 3 to the surface on the side of the base material 2 (exemplified as external light) and light from the surface on the side of the base material 2 to the surface on the side of the cover layer 3 (exemplified as light from the backlight of a display device used in combination with the electrostatic capacitance type sensor 1) hardly pass through the non-detection region 25.

[0044] As Figure 1 characterized in [description], a first transparent electrode 8 and a second transparent electrode 12 are provided on the front surface 2a of the base material 2. The first transparent electrode 8 is disposed in the detection region 11 and has a plurality of first transparent electrode portions 4. As Figure 3 and Figure 4 shown, a plurality of first transparent electrode portions 4 are provided on the front surface 2a. Each first transparent electrode portion 4 is connected in the Y1-Y2 direction (first direction) via an elongated connecting portion 7. Moreover, the first transparent electrode 8 having a plurality of first transparent electrode portions 4 connected in the Y1-Y2 direction is arranged at intervals in the X1-X2 direction. The connecting portion 7 is made of the same material as the first transparent electrode portion 4 and is formed integrally with the continuously provided first transparent electrode portions 4. The connecting portion 7 electrically connects two adjacent first transparent electrode portions 4 to each other.

[0045] The first transparent electrode portion 4 and the connecting portion 7 have light transmissivity and are formed of crystalline ITO. Crystalline ITO can be directly formed into a film on the base material 2, or amorphous ITO can be formed into a film on the base material 2 and crystallized by heat treatment. By performing crystallization, the resistance value can be reduced and the conductivity can be improved. As described later, in an input device which is one of the uses of the electrostatic capacitance type sensor 1, the size of the light-emitting body of the display element becomes smaller, for example, the arrangement pitch becomes about 20 μm or less. At this time, from the viewpoint of ensuring the design freedom of the transparent electrode, it is desired to reduce the resistance value of the transparent electrode arranged to overlap with the display element. Specifically, the requirement to narrow the width of the connecting portion 7 is increased, and in order to respond to this requirement, it is necessary to reduce the resistance value of the transparent conductive material constituting the connecting portion 7. Therefore, it is desired that the ITO constituting the connecting portion 7 is not amorphous but crystalline ITO. The thickness of the film-shaped first transparent electrode portion 4 and the connecting portion 7 formed on the base material 2 is, for example, in the range of 20 nm to 150 nm, and in some cases, it is preferably in the range of 20 nm to 60 nm, and more preferably in the range of 30 nm to 50 nm.

[0046] The second transparent electrode 12 is disposed in the detection region 11 and has a plurality of second transparent electrode portions 5. AsFigure 3 and Figure 4 As shown, a plurality of second transparent electrode portions 5 are provided on the front surface 2a of the base material 2. In this way, the second transparent electrode portions 5 are provided on the same surface (the front surface 2a of the base material 2) as the first transparent electrode portion 4. Each second transparent electrode portion 5 is connected via an elongated bridging wiring portion 10 in the X1-X2 direction (the second direction). And the second transparent electrode 12 having a plurality of second transparent electrode portions 5 connected in the X1-X2 direction is arranged at intervals in the Y1-Y2 direction. The bridging wiring portion 10 and the second transparent electrode portion 5 are formed as separate bodies. In addition, the X1-X2 direction intersects the Y1-Y2 direction. For example, the X1-X2 direction is perpendicular to the Y1-Y2 direction.

[0047] The second transparent electrode portion 5 is formed of a light-transmissive conductive material. The second transparent electrode portion 5 is preferably formed of crystalline ITO in the same manner as the material of the first transparent electrode portion 4. As will be described later, in the capacitive sensor 1, the thickness of the second transparent electrode portion 5 is 30 nm or more and 50 nm or less. The thickness of the second transparent electrode portion 5 may be equal to the thickness of the first transparent electrode portion 4 and the connecting portion 7.

[0048] The bridging wiring portion 10 has light transmissivity and is formed of a material containing an amorphous oxide-based material. As the amorphous oxide-based material, at least one selected from the group consisting of amorphous ITO (Indium Tin Oxide), amorphous IZO (Indium Zinc Oxide), amorphous GZO (Gallium-doped Zinc Oxide), amorphous AZO (Aluminum-doped Zinc Oxide), and amorphous FTO (Fluorine-doped Zinc Oxide) can be used. From the viewpoints of low resistance value, excellent processability (selective etching property with respect to crystalline ITO), and excellent invisibility, the bridging wiring portion 10 is preferably composed of amorphous IZO.

[0049] As Figures 2 to 4 shown, an insulating layer 20 is provided on the surface of the connecting portion 7 that connects between the first transparent electrode portions 4. As Figure 3As shown, the insulating layer 20 fills the space between the connection portion 7 and the second transparent electrode portion 5, and also covers the surface of the second transparent electrode portion 5. As the insulating layer 20, a cured product of a resin-based material, such as a photosensitive transparent resin (examples include novolak-based and acrylic-based materials), is used. There are cases where the refractive index of the insulating layer 20 is preferably in the range of 1.5 to 2.0. Since the refractive index of the crystalline ITO constituting the first transparent electrode portion 4 and the second transparent electrode portion 5 is in the range of 1.8 to 2.3, and as a specific example of the amorphous oxide-based material constituting the bridging wiring portion 10, the refractive index of amorphous IZO is in the range of 1.9 to 2.3, therefore, when the refractive index of the insulating layer 20 is in the range of 1.5 to 2.0, the refractive index difference between the bridging wiring portion 10 and the members in its vicinity becomes smaller, and the invisibility of the bridging wiring portion 10 is likely to be improved. From the viewpoint of more stably improving the invisibility of the bridging wiring portion 10, there are cases where the refractive index of the insulating layer 20 is preferably in the range of 1.8 to 2.0.

[0050] As Figure 3 and Figure 4 shown, the bridging wiring portion 10 is provided from the surface 20a of the insulating layer 20 to the surfaces of the respective second transparent electrode portions 5 located on both sides in the X1 - X2 direction of the insulating layer 20. The bridging wiring portion 10 electrically connects two adjacent second transparent electrode portions 5 to each other. The width L1 of the bridging wiring portion 10 is determined in consideration of the electrical characteristics (especially the resistance value) desired for the bridging wiring portion 10, the thickness of the bridging wiring portion 10 (bridging thickness TB) described later, and the invisibility of the bridging wiring portion 10, etc. Recently, due to the increasing requirement for improving the invisibility of the bridging wiring portion 10, the width L1 of the bridging wiring portion 10 has a tendency to become narrower. Specifically, the width L1 of the bridging wiring portion 10 is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 50 μm or less. When the capacitive sensor 1 is disposed on a light source, due to the miniaturization of the light-emitting body being promoted, there are cases where the width L1 of the bridging wiring portion 10 is preferably 40 μm or less, and more preferably 20 μm or less.

[0051] As Figure 3 and Figure 4 shown, an insulating layer 20 is provided on the surface of the connection portion 7 that connects the respective first transparent electrode portions 4, and a bridging wiring portion 10 that connects the respective second transparent electrode portions 5 is provided on the surface of the insulating layer 20. Thus, the insulating layer 20 exists between the connection portion 7 and the bridging wiring portion 10, and the first transparent electrode portion 4 and the second transparent electrode portion 5 are in an electrically insulated state. In addition, in the present embodiment, since the first transparent electrode portion 4 and the second transparent electrode portion 5 are provided on the same surface (the front surface 2a of the substrate 2), the capacitive sensor 1 can be made thinner.

[0052] In addition, Figures 2 to 4 the connecting portion 7 shown in Figures 2 to 4 is formed integrally with the first transparent electrode portion 4 and extends in the Y1 - Y2 direction. In addition, Figures 2 to 4 the bridging wiring portion 10 shown in Figures 2 to 4 is formed separately from the second transparent electrode portion 5 on the surface 20a of the insulating layer 20 covering the connecting portion 7 and extends in the X1 - X2 direction. However, the arrangement forms of the connecting portion 7 and the bridging wiring portion 10 are not limited thereto. For example, the connecting portion 7 may be formed integrally with the first transparent electrode portion 4 and extend in the X1 - X2 direction. In this case, the connecting portion 7 electrically connects two adjacent second transparent electrode portions 5 to each other. The bridging wiring portion 10 is formed separately from the first transparent electrode portion 4 on the surface 20a of the insulating layer 20 covering the connecting portion 7 and extends in the Y1 - Y2 direction. In this case, the bridging wiring portion 10 electrically connects two adjacent first transparent electrode portions 4 to each other. In the description of the capacitive sensor 1 according to the present embodiment, the following case is given as an example: the bridging wiring portion 10 is formed separately from the second transparent electrode portion 5 on the surface 20a of the insulating layer 20 covering the connecting portion 7 and extends in the X1 - X2 direction.

[0053] As Figure 1 shown, a plurality of wiring portions 6 are formed in the non - detection region 25 and are led out from each of the first transparent electrodes 8 and each of the second transparent electrodes 12. The first transparent electrodes 8 and the second transparent electrodes 12 are electrically connected to the wiring portions 6 via the connection wirings 16 respectively. Each wiring portion 6 is connected to an external connection portion 27 that is electrically connected to a flexible printed circuit board (not shown). That is, each wiring portion 6 electrically connects the first transparent electrodes 8 and the second transparent electrodes 12, and the external connection portion 27. The external connection portion 27 is electrically connected to a flexible printed circuit board (not shown) via, for example, a conductive paste, a material having a metal such as Cu, Cu alloy, CuNi alloy, Ni, Ag, Au, etc.

[0054] Each wiring portion 6 is formed of a material having a metal such as Cu, Cu alloy, CuNi alloy, Ni, Ag, Au, etc. The connection wiring 16 is formed of a transparent conductive material such as ITO, metal nanowires, etc. and extends from the detection region 11 to the non - detection region 25. The wiring portions 6 are laminated on the connection wiring 16 in the non - detection region 25 and are electrically connected to the connection wiring 16.

[0055] The wiring portions 6 are provided in a part of the non - detection region 25 located on the front surface 2a of the base material 2. The external connection portion 27 is also provided in a part of the non - detection region 25 on the front surface 2a of the base material 2 in the same manner as the wiring portions 6.

[0056] In Figure 1In [the figure], the wiring portion 6 and the external connection portion 27 are shown for easy understanding so as to be visually recognizable. However, actually, a decorative layer (not shown) having light-shielding properties is provided in a portion located in the non-detection region 25. Therefore, when viewing the capacitive sensor 1 from the surface on the side of the cover layer 3, the wiring portion 6 and the external connection portion 27 are blocked by the decorative layer and cannot be visually recognized. The material constituting the decorative layer can be arbitrary as long as it has light-shielding properties. The decorative layer may also have insulating properties.

[0057] In the capacitive sensor 1 according to the present embodiment, as Figure 3 shown, for example, when a finger as an example of an operating body touches the surface 3a of the cover layer 3, capacitances are generated between the finger and the first transparent electrode portion 4 close to the finger and between the finger and the second transparent electrode portion 5 close to the finger. The capacitive sensor 1 can calculate the contact position of the finger based on the capacitance change at this time. The capacitive sensor 1 detects the X coordinate of the finger position based on the capacitance change between the finger and the first transparent electrode 8, and detects the Y coordinate of the finger position based on the capacitance change between the finger and the second transparent electrode 12 (self-capacitance detection type).

[0058] Alternatively, the capacitive sensor 1 may be a mutual capacitance detection type. That is, the capacitive sensor 1 may apply a driving voltage to a row of any one of the first transparent electrode 8 and the second transparent electrode 12, and detect the change in the capacitance between the finger and any other one of the first transparent electrode 8 and the second transparent electrode 12. Thereby, the capacitive sensor 1 detects the Y coordinate of the finger position through the other electrode and detects the X coordinate of the finger position through one electrode.

[0059] In the capacitive sensor 1 according to the present embodiment, when the thickness of the second transparent electrode portion 5 is set to TE and the thickness of the bridging wiring portion 10 is set to TB, the following formula (1) and the following formula (2) are satisfied.

[0060] 0.28×TE + 83 nm ≤ TB ≤ 0.69×TE + 105 nm (1)

[0061] 30 nm ≤ TE ≤ 50 nm (2)

[0062] Hereinafter, these ranges will be described.

[0063] As Figures 1 to 4As shown, a first transparent electrode portion 4 and a second transparent electrode portion 5, both made of crystalline ITO, are provided on a substrate 2 made of a COP film by pattern formation. An insulating layer 20 made of a cured product of a photosensitive resist resin is provided between an adjacent first transparent electrode portion 4 and a connecting portion 7 that electrically connects them, and a bridging wiring portion 10 made of amorphous IZO is provided thereon. Two adjacent second transparent electrode portions 5 are electrically connected by the bridging wiring portion 10. A structure thus obtained (hereinafter referred to as "test structure") is prepared by making the thicknesses of a plurality of bridging wiring portions 10 different. An environmental test is conducted on this structure by placing it in an environment of 85°C and 85% RH for 240 hours. The resistance value of the second transparent electrode 12 including the bridging wiring portion 10 is measured before and after the environmental test, and the hourly change rate (unit: % / hour, [resistance value after the test - resistance value before the test] / resistance value before the test × 100 / test time) is obtained. The results are shown in Table 1.

[0064] [Table 1]

[0065] Thickness of the bridging wiring portion 60 nm 80 nm 100 nm 120 nm Rate of change per hour [% / hr] 0.1 0.05 0.03 0.02 Judgment Non-conforming Conforming Good Good

[0066] It was confirmed that the thicker the thickness of the bridging wiring portion 10, the lower the hourly resistance change rate. It is assumed that if the thickness of the bridging wiring portion 10 is 80 nm or more, the hourly resistance change rate will be sufficiently low even after 1000 hours in a normal environment (25°C and 50% RH). From the viewpoint of excellent environmental resistance, the thickness of the bridging wiring portion 10 is preferably 90 nm or more, and particularly preferably 100 nm or more.

[0067] For the test structures with different thicknesses of the bridging wiring portion 10, the influence of a weakly acidic etching solution that dissolves and removes the amorphous IZO used in the pattern formation process of the bridging wiring portion 10 on the first transparent electrode portion 4 and the second transparent electrode portion 5 made of crystalline ITO is confirmed. Specifically, the degree of etching residue of the constituent material of the bridging wiring portion 10 is confirmed. The results are shown in Figure 5 shown.

[0068] As Figure 5As shown, until the thickness of the bridging wiring portion 10 reaches 140 nm, after the shaping of the bridging wiring portion 10, the surfaces of the first transparent electrode portion 4 and the second transparent electrode portion 5 made of crystalline ITO are not affected, and no defective conditions such as residual residues can be seen. In contrast, when the thickness of the bridging wiring portion 10 is 160 nm, residues can be seen on the entire surfaces of the first transparent electrode portion 4 and the second transparent electrode portion 5. This residue causes the coloring of the first transparent electrode portion 4 and the second transparent electrode portion 5, and causes a decrease in transmittance. Therefore, when the first transparent electrode portion 4 and the second transparent electrode portion 5 are made of crystalline ITO and the bridging wiring portion 10 is made of amorphous IZO, it is preferable that the thickness of the bridging wiring portion 10 is less than 160 nm.

[0069] Prepare test structures with different thicknesses of the base material 2 (40 μm), the insulating layer 20 (1.5 μm), the thickness of the first transparent electrode portion 4 and the second transparent electrode portion 5 (hereinafter referred to as "electrode thickness TE"), and the thickness of the bridging wiring portion 10 (hereinafter referred to as "bridging thickness TB"). Use a spectrophotometer ("CM3700A" manufactured by Konica Minolta) to measure the spectral transmittance data tE(λ) of the portion where the base material 2 and the first transparent electrode portion 4 are laminated (the base portion) and the spectral transmittance data tB(λ) of the portion where the base material 2, the first transparent electrode portion 4, the insulating layer 20, and the bridging wiring portion 10 are laminated (the bridging portion).

[0070] As light source information, measure the spectral photometric data Sw(λ) of white light and the spectral photometric data Sg(λ) of green light of the organic EL light-emitting element. The respective spectral data are shown in Figure 6 (a) of Figure 6 and

[0071] Use the measured spectral transmittance data tE(λ) of the base portion, the spectral photometric data Sw(λ) of white light, and the three stimulus values x(λ), y(λ), z(λ) of the color matching function of the XYZ colorimetric system to obtain the color mixture amounts X0, Y0, Z0 of the base portion in the XYZ colorimetric system. In addition, the three stimulus values x(λ), y(λ), z(λ) of the color matching function of the XYZ colorimetric system are shown in Figure 6 (c) of

[0072] Similarly, use the measured spectral transmittance data tB(λ) of the bridging portion, the spectral photometric data Sw(λ) of white light, and the stimulus values x(λ), y(λ), z(λ) of the color matching function of the XYZ colorimetric system to obtain the color mixture amounts X, Y, Z of the bridging portion in the XYZ colorimetric system.

[0073] Based on these values, obtain the color difference ΔE for the case of white light according to the following formula (3).

[0074] ΔE = {(X - X0) 2 + (Y - Y0) 2 + (Z - Z0) 2} 1 / 2 (3)

[0075] Regarding the electrode thickness TE of 50 nm, the color difference ΔE is also obtained for green in the same manner.

[0076] The obtained color difference ΔE is summarized and shown in Table 2.

[0077] [Table 2]

[0078]

[0079] Under the conditions of each electrode thickness TE, the change rate R (unit: %, [color difference ΔE - minimum color difference ΔE0] / minimum color difference ΔE0 × 100) of the color difference ΔE that is the smallest with respect to the bridging thickness TB is obtained. The results are shown in Table 3. The bridging thickness TB for which R becomes "0%" in Table 3 is the bridging thickness TB that gives the minimum color difference ΔE0 at the electrode thickness TE.

[0080] [Table 3]

[0081]

[0082] The results of Table 2 are shown in Figure 7 The results of the white light source in Table 3 are shown in Figure 8 The influence of the light source in the case where the electrode thickness TE is 50 nm among the results of Table 3 is shown in Figure 9 shown.

[0083] As shown in Table 2 and Figure 7 , compared with the case where the second transparent electrode portion 5 (electrode thickness TE = 0 nm) is not provided at the base, by providing the second transparent electrode portion 5 at the base, regardless of the bridging thickness TB, a basic tendency of a lower color difference ΔE can be seen. In addition, regardless of the electrode thickness TE, the relationship between the bridging thickness TB and the color difference ΔE is not a monotonically increasing or monotonically decreasing relationship, and a tendency for the color difference ΔE to specifically decrease at a given bridging thickness TB is confirmed.

[0084] This tendency is in Table 3 and Figure 8It is more clearly confirmed that, in the case of a white light source, when the electrode thickness TE is 0 nm, the bridging thickness TB that gives the minimum color difference ΔE0 is 100 nm; when the electrode thickness TE is 30 nm and 35 nm, the bridging thickness TB that gives the minimum color difference ΔE0 is 110 nm; and when the electrode thickness TE is 50 nm, the bridging thickness TB that gives the minimum color difference ΔE0 is 120 nm. Thus, it can be seen that the thicker the electrode thickness TE is from 0 nm, the thicker the bridging thickness TB that gives the minimum color difference ΔE0 becomes. There is a possibility that the interference between the light passing through the base portion and the light passing through the bridging portion has an impact.

[0085] In addition, as Figure 9 shown, it is confirmed that, compared with the case of a white light source, in the case of a green light source, the change in the minimum color difference ΔE0 and the color difference ΔE at other bridging thicknesses TB is more significant.

[0086] Based on Table 3, in the case where the light source is white, for different electrode thicknesses TE, the bridging thickness TB at which the change rate R becomes 100% and 50% is obtained by interpolation. The results are shown in Table 4 appended to the data shown in Table 3. In Table 4, the results with a change rate R of 0% are underlined, the results with a change rate R of 50% are shown in bold, and the results with a change rate R of 100% are shown in italic.

[0087] [Table 4]

[0088]

[0089] Figure 10 The content of Table 4 is charted. In Figure 10 , the case where the change rate R is 50% is shown as a white circle (○), and the case where the change rate R is 100% is shown as a black circle (●). From these results, it is confirmed that as the electrode thickness TE increases, the bridging thickness TB at which the change rate R becomes 0% increases. Similarly, it is confirmed that as the electrode thickness TE increases, the overall range of the bridging thickness TB at which the change rate R is 50% or less shifts to the right (the side with a larger bridging thickness TB) in Figure 10 .

[0090] Figure 11 is a chart showing the results of plotting the results with a change rate R of 0% and the results with a change rate R of 50% in Table 4 in a coordinate system with the electrode thickness TE as the horizontal axis and the bridging thickness TB as the vertical axis (hereinafter referred to as the "TE-TB coordinate system"). In Figure 11Among them, the results where the change rate R becomes 0% are shown as black circles (●), and the results where the change rate R becomes 50% are shown as white circles (○). When the electrode thickness TE is 0 nm, since the situation is different from other cases, an approximate formula is obtained based on the results of the electrode thicknesses TE of 30 nm, 35 nm, and 50 nm. The results are characterized in Figure 11 as follows.

[0091] Using the results where the change rate R becomes 0% in Table 4 (specifically, the points where (TE[nm], TB[nm]) = (30, 110), (35, 110), (50, 120) in the TE - TB coordinate system) to obtain an approximate formula. The obtained approximate formula can be characterized by the following formula (4). The following formula (4) is shown as a one-dot chain line M0 in Figure 11 as follows.

[0092] TB = 0.54 × TE + 93 nm (4)

[0093] Using the results of the upper limit of the range where the change rate R is 50% or less in Table 4 (specifically, the points where (TE[nm], TB[nm]) = (30, 127), (35, 127), (50, 140) in the TE - TB coordinate system), to obtain the formula for the upper limit of the range where the change rate R is 100% or less. As a result, the following formula (5) is obtained. The following formula (5) is shown as a dashed line M1 in Figure 11 as follows.

[0094] TB = 0.69 × TE + 105 nm (5)

[0095] Similarly, using the results of the lower limit of the range where the change rate R is 50% or less (specifically, the points where (TE[nm], TB[nm]) = (30, 91), (35, 94), (50, 97) in the TE - TB coordinate system), to obtain the formula for the lower limit of the range where the change rate R is 100% or less. As a result, the following formula (6) is obtained. The following formula (6) is shown as a dashed line M2 in Figure 11 as follows.

[0096] TB = 0.28 × TE + 83 nm (6)

[0097] From the viewpoints of the electrical characteristics, invisibility (lightness of hue), and processability (ease of crystallization based on heat treatment) of the first transparent electrode portion 4 and the second transparent electrode portion 5, the electrode thickness TE is set within the range of the following formula (2).

[0098] 30 nm ≤ TE ≤ 50 nm (2)

[0099] When the electrode thickness TE is too small, the resistance value tends to be high. When the base material 2 is made of a resin-based base material, for the ITO provided thereon, there is a case where it is formed by first forming an amorphous film and crystallizing it by heat treatment to reduce the resistance value. However, when the electrode thickness TE is too small, the crystallization based on this heat treatment sometimes hardly progresses. On the other hand, when the electrode thickness TE is too large, it causes coloring. In addition, there is a case where the insulating portion 21 between the first transparent electrode portion 4 and the second transparent electrode portion 5 is formed by removing the conductive ITO. In this case, the thicker the electrode thickness TE, the lower the workability (pattern etching property), and the more likely the shape accuracy after processing is to be reduced.

[0100] Therefore, by setting the electrode thickness TE and the bridging thickness TB so as to satisfy the above formula (1) and the above formula (2), the capacitive sensor 1 with excellent environmental resistance, workability, and invisibility can be obtained. In other words, satisfying the above formula (1) and the above formula (2) means setting the electrode thickness TE and the bridging thickness TB so as to be within the range of the quadrilateral P1P2P3P4 formed by the following four points P1 to P4 in the TE-TB coordinate system.

[0101] P1(TE [nm], TB [nm]) = (50, 140)

[0102] P2(TE [nm], TB [nm]) = (30, 126)

[0103] P3(TE [nm], TB [nm]) = (30, 91)

[0104] P4(TE [nm], TB [nm]) = (50, 97)

[0105] Regarding the case where both the above formula (1) and the above formula (2) are satisfied, the case where the bridging thickness TB is too thin, and the case where the bridging thickness TB is too thick, the results of observing the test structure are specifically shown below.

[0106] Figure 12 It is a diagram conceptually showing the structure of the test structure within the observation field of view. As Figure 12 shown, the first transparent electrode portion 4, the second transparent electrode portion 5, the insulating portion 21, the insulating layer 20, and the bridging wiring portion 10 are arranged in the observation field of view. In Figure 12 , the insulating layer 20 characterized by a substantially rectangular shape is 300 μm × 340 μm in size.

[0107] Figure 13This is a diagram showing observation images in the cases where the light source is white and green for three types of wiring structures. In the wiring structure according to Comparative Example 1, the electrode thickness TE is 50 nm and the bridging thickness TB is 90 nm. In the wiring structure according to Example 1, the electrode thickness TE is 50 nm and the bridging thickness TB is 120 nm. In the wiring structure according to Comparative Example 2, the electrode thickness TE is 50 nm and the bridging thickness TB is 150 nm. The results of the sensory evaluation of the invisibility of observing the wiring structures according to the respective examples under a green light source are shown in Figure 13 on the lower layer. In addition, since green is the color with the highest sensitivity to brightness changes in the human eye, the light source in the sensory evaluation is set to green.

[0108] The sensory evaluation is specifically carried out by the following method. The wiring structure is arranged on the light irradiation surface of a light source with an organic EL light-emitting element as the light emitter, and a polarizing plate with a transmission direction along the bridging direction (X1 - X2 direction) of the bridging wiring portion 10 is arranged thereon to prepare an observation object. The observation object is visually observed from the side where the polarizing plate is arranged under sunlight and a fluorescent lamp. When observing, observe along the stacking direction (Z1 - Z2 direction) of the observation object, or from a direction slightly inclined to the stacking direction, and observe the observation object while moving the line of sight. Since it is an observation under visual inspection, although the shape of the bridging wiring portion 10 cannot be directly visually recognized, observe the Figure 12 area shown. When the bridging wiring portion 10 is not conspicuous in comparison with the surrounding first transparent electrode portion 4 and second transparent electrode portion 5 and it is difficult to visually recognize the flicker when moving the line of sight, it is determined that the invisibility is good ( Figure 13 shown as "A" in). In contrast, when the bridging wiring portion 10 is conspicuous in comparison with the surrounding first transparent electrode portion 4 and second transparent electrode portion 5 and it is easy to visually recognize the flicker when moving the line of sight, it is determined that the invisibility is poor ( Figure 13 shown as "B" in).

[0109] As a result, as Figure 13 shown, in the stacked structure of Example 1 within the range of the bridging thickness TB where the change rate R becomes 50% or less in Figure 11 , good invisibility can be obtained. In contrast, in the stacked structures of Comparative Example 1 and Comparative Example 2 within the range of the bridging thickness TB where the change rate R exceeds 50% in Figure 11 , good invisibility cannot be obtained. Therefore, it is confirmed that by setting the electrode thickness TE and the bridging thickness TB so that it is within the range of the quadrilateral P1P2P3P4 in Figure 11 , a capacitive sensor 1 with good invisibility can be obtained.

[0110] Figure 14 This is an explanatory diagram of an input device according to an embodiment of the present invention. As Figure 14 shown, the input device 100 according to this embodiment includes: a light source; the capacitive sensor 1 according to the above-described embodiment; and a light source 200. The capacitive sensor 1 opposes the light source 200 to the substrate 2 side (Z2 side in the Z1-Z2 direction). The light source 200 can irradiate light toward the Z1 side in the Z1-Z2 direction. As a specific example of the light source 200, an organic EL light-emitting element (OLED), a laminated structure including a liquid crystal optical element and a light source, a micro LED array obtained by arranging micro LEDs on a substrate, etc. can be cited. Even if the light source 200 is composed of an integrated body of a plurality of light-emitting bodies and the arrangement pitch of the plurality of light-emitting bodies is 20 μm or less, the capacitive sensor 1 according to this embodiment can suitably have electrical characteristics (particularly, resistance value) and has invisibility.

[0111] The embodiments described above are described to facilitate understanding of the present invention and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments conforms to the following principle: It also includes all design changes and equivalents belonging to the technical scope of the present invention.

[0112] Explanation of reference numerals

[0113] 1: Capacitive sensor

[0114] 2: Substrate

[0115] 2a: Front surface

[0116] 3: Cover layer

[0117] 3a: Surface

[0118] 4: First transparent electrode portion

[0119] 5: Second transparent electrode portion

[0120] 6: Wiring portion

[0121] 7: Connecting portion

[0122] 8: First transparent electrode

[0123] 10: Bridging wiring portion

[0124] 11: Detection area

[0125] 12: Second transparent electrode

[0126] 16: Connection wiring

[0127] 20: Insulating layer

[0128] 20a: Surface

[0129] 21: Insulating portion

[0130] 25: Non-detection area

[0131] 27: External connection portion

[0132] 30: Optically transparent adhesive layer

[0133] 100: Input device

[0134] 200: Light source

[0135] A1: Area

[0136] L1: Width of the bridging wiring portion

[0137] M0, M1, M2: Approximate straight lines in the TE-TB coordinate system

[0138] P1, P2, P3, P4: Points in the TE-TB coordinate system

[0139] R: Rate of change

[0140] TB: Bridging thickness

[0141] TE: Electrode thickness

[0142] ΔE: Color difference.

Claims

1. An electrostatic capacitance type sensor, characterized in that, Comprising: a substrate having light transmissivity; a first transparent electrode including a plurality of first transparent electrode portions arranged along a first direction of the substrate and having light transmissivity, and connection portions integrally provided with the first transparent electrode portions and electrically connecting two adjacent first transparent electrode portions to each other; a second transparent electrode including a plurality of second transparent electrode portions arranged along a second direction intersecting the first direction of the substrate and having light transmissivity, and bridging wiring portions separately provided from the second transparent electrode portions and electrically connecting two adjacent second transparent electrode portions to each other; and an insulating layer formed between the first transparent electrode and the bridging wiring portions, wherein the second transparent electrode portions are made of crystalline ITO, and the bridging wiring portions are made of amorphous IZO, when the thickness of the second transparent electrode portions is TE and the thickness of the bridging wiring portions is TB, the following formula (1) and the following formula (2) are satisfied: 0.28×TE + 83 nm ≤ TB ≤ 0.69×TE + 105 nm (1) 30 nm ≤ TE ≤ 50 nm (2).

2. The capacitive sensor according to claim 1, wherein the substrate has a resin film.

3. The capacitive sensor according to claim 1, wherein the first transparent electrode is formed of crystalline ITO, the thickness of the first transparent electrode is equal to the thickness of the second transparent electrode portions, and the first transparent electrode and the bridging wiring portions intersect with each other with the insulating layer therebetween.

4. The capacitive sensor according to claim 1, wherein the insulating layer is made of a resin-based material and has a refractive index of 1.5 or more and 2.0 or less.

5. An input device, characterized in that, Comprising: the capacitive sensor according to claim 1; and a light source provided on the substrate side of the capacitive sensor.

6. The input device according to claim 5, wherein the light source is an organic EL light-emitting element.

7. The input device according to claim 5 or 6, wherein the light source is composed of an assembly of a plurality of light-emitting bodies, and the arrangement pitch of the plurality of light-emitting bodies is 20 μm or less.

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