JP2017226111A - Laminate, see-through electrode, touch panel and display device having touch position detection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently prevent a warp from occurring, in a laminate and a see-through electrode having excellent flexibility.SOLUTION: A laminate includes a transparent base material film having flexibility and a conductor formation layer formed on the base material film. The conductor formation layer includes a body layer including copper, a low reflection layer including copper nitride and arranged between the body layer and the material film, and a second low reflection layer including copper nitride and arranged on a side opposite to the low reflection layer with regard to the body layer. A tensile internal stress of the body layer measured using an X-ray diffraction method is within a range of -130 MPa to 20 MPa, inclusive.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a flexible laminate and a transparent electrode. The present invention also relates to a touch panel provided with a transparent electrode. The present invention also relates to a display device with a touch position detection function obtained by combining a touch panel and a display device.

  Today, touch panel devices are widely used as input means. The touch panel device includes a touch panel, a control circuit that detects a contact position on the touch panel, wiring, and an FPC (flexible printed circuit board). In many cases, the touch panel device includes various devices in which a display device such as a liquid crystal display or an organic EL display is incorporated (for example, a ticket vending machine, an ATM device (automatic teller machine), a mobile phone, a game, etc. It is used together with a display device as an input means for a computer, a notebook PC (Notebook Personal Computer), a smartphone, and a tablet terminal. In such a device, the touch panel is arranged on the display surface of the display device, and thereby, a very direct input to the display device, particularly the position coordinates of the display image and the information associated with the position coordinates. Input is possible. The area of the touch panel that faces the display area of the display device is transparent, and this area of the touch panel constitutes an active area that can detect the contact position (or approach position).

  As a touch panel, a projected capacitive coupling type touch panel is known. In a capacitively coupled touch panel, a parasitic capacitance is newly generated when an external conductor (typically a finger) whose position is to be detected contacts (or approaches) the touch panel via a dielectric. The position of the external conductor on the touch panel is detected on the basis of the change in capacitance caused by the parasitic capacitance. Such a projected capacitively coupled touch panel includes, for example, a transparent electrode including a transparent base material such as a PET film and a plurality of conductive patterns provided on the transparent base material. The conductive pattern is made of, for example, a transparent conductive material made of ITO (indium tin oxide) having translucency and conductivity.

  In addition, in order to reduce the electrical resistance value of the conductive pattern and thereby improve the detection accuracy of the touch position, a metal material such as silver or copper having higher conductivity than the transparent conductive material is used as a material constituting the conductive pattern. It has been proposed to use (see, for example, Patent Document 1). However, since these metal materials are opaque, when the conductive pattern is made of a metal material, the conductive pattern has an opening for transmitting the image light from the display device at an appropriate ratio. For example, the conductive pattern is composed of conductive wires arranged in a mesh shape.

  By the way, metal materials, such as copper, show a metallic luster, while having high electroconductivity. For this reason, when an untreated metal material is used as a conducting wire, the visibility of the image light from the display device is hindered by the metallic luster of the conducting wire. In particular, copper exhibits a reddish color peculiar to copper, so that it is more conspicuous than other metal materials such as silver, and this hinders the visibility of image light from the display device. In order to reduce such metallic luster peculiar to copper, for example, in the above-mentioned Patent Document 1, it is proposed to reduce the metallic luster of the conductive wire by providing a low reflective layer made of copper nitride on the surface of the metal layer. Has been.

JP 2013-169712 A

  As a method of manufacturing a flexible wiring substrate such as a transparent electrode used for a touch panel, the above-described low reflection layer or metal is formed on a long resin substrate that is supplied and conveyed by a roll-to-roll method. A method of forming a long wiring board by forming a layer and winding the wiring board into a roll is conceivable. Here, the “roll-to-roll method” means that a long belt-like flexible substrate is unwound from a take-up (roll), supplied, and subjected to predetermined processing. Later, it refers to a processing method of winding into a winding (roll) form. As a method for forming the low reflective layer and the metal layer, a known thin film forming method such as a sputtering method can be used.

  By the way, when the inventors of the present invention have made extensive studies for producing a wiring board having excellent flexibility, they have obtained the following knowledge. That is, when a conductive wire forming layer including a low reflection layer and a metal layer is formed by sputtering, high energy particles such as recoil Ar atoms are taken into the conductive wire forming layer, thereby causing internal stress (tensile tension) in the conductive wire forming layer. Stress or compressive stress). In order to increase the flexibility of the wiring board, it is necessary to reduce the thickness of the base film. However, when the conductive wire forming layer is formed on the thin base film, the base film and the relevant film are caused by the internal stress of the conductive wire forming layer. There is a possibility that warpage occurs in the laminate with the conductive wire forming layer. When warpage occurs in the laminated body, it becomes extremely difficult to form a fine conductive pattern by a photolithography method in a later process.

  Moreover, when forming a conducting wire formation layer by sputtering, the conducting wire formation layer is also deposited on a member around the target such as an earth shield. When the formation of the conductive wire forming layer is repeated using the same sputtering apparatus, the conductive wire forming layers are laminated in multiple stages on the member around the target, and the internal stress of each layer is increased by integrating the internal stress of each layer. Thus, the laminated film is likely to be partially peeled from the members around the target. When a part of the laminated film is peeled off, the fragments may fall on the base film as a foreign substance, which may cause an appearance defect due to a dent.

  The present invention has been made in consideration of such points. An object of the present invention is to sufficiently suppress the occurrence of warpage in a laminate and a transparent electrode having excellent flexibility.

The present invention
A transparent base film having flexibility;
A conductor forming layer provided on the base film;
With
The conducting wire forming layer is
A body layer made of copper;
A low reflection layer made of copper nitride, disposed between the main body layer and the substrate film;
A second low reflection layer made of copper nitride disposed on the opposite side of the main reflection layer from the low reflection layer;
Including
The laminate is a laminate in which a tensile internal stress of the main body layer measured using an X-ray diffraction method is in a range of −130 MPa to 20 MPa.

Alternatively, the present invention provides
A transparent base film having flexibility;
A plurality of conductive patterns provided on the base film;
With
The conductive pattern is a conductive wire having a light shielding property, and is composed of conductive wires arranged in a mesh shape so that an opening is formed between the conductive wires,
The conducting wire is
A body layer made of copper;
A low reflection layer made of copper nitride, disposed between the main body layer and the substrate film;
A second low reflection layer made of copper nitride disposed on the opposite side of the main reflection layer from the low reflection layer;
Including
It is a see-through electrode whose tensile internal stress of the said main body layer measured using a X ray diffraction method exists in the range of -130 Mpa or more and 20 Mpa or less.

  A touch panel provided with the above-described transparent electrode according to the present invention is also included in the scope of the present invention.

A display device;
A touch panel according to the present invention described above, disposed on the display surface of the display device;
A display device with a touch position detection function provided with the above is also included in the scope of the present invention.

  According to the present invention, it is possible to sufficiently suppress the occurrence of warpage in a wiring board and a transparent electrode having excellent flexibility.

FIG. 1 is a plan view showing a transparent electrode in the first embodiment of the present invention. 2A is an enlarged plan view showing a conductive pattern in a portion surrounded by an alternate long and short dash line denoted by reference numeral II in FIG. FIG. 2B is an enlarged plan view showing a modification of the conductive pattern. FIG. 3 is a cross-sectional view showing a case where the transparent electrode is cut along line III in FIG. 2A. FIG. 4 is an enlarged cross-sectional view of the transparent substrate and the conductor shown in FIG. FIG. 5A is a diagram for explaining a method of manufacturing a transparent electrode. FIG. 5B is a diagram for explaining a method of manufacturing a transparent electrode. FIG. 5C is a diagram for explaining a method of manufacturing a transparent electrode. FIG. 5D is a diagram for explaining a method of manufacturing the transparent electrode. FIG. 5E is a diagram for explaining a method of manufacturing a transparent electrode. FIG. 6 is a development view showing a display device with a touch position detection function according to the second embodiment of the present invention. FIG. 7 is a plan view showing a touch panel of the display device with a touch position detection function of FIG. FIG. 8 is an enlarged plan view showing a conductive pattern of a portion surrounded by a one-dot chain line denoted by reference numeral XVI in FIG. FIG. 9 is a cross-sectional view showing a case where the touch panel is cut along the line XVII in FIG. 10 is an enlarged cross-sectional view of a part of the touch panel shown in FIG. FIG. 11 is a cross-sectional view showing a modification of the touch panel according to the second embodiment of the present invention. FIG. 12 is a cross-sectional view showing a modification of the touch panel according to the second embodiment of the present invention. FIG. 13 is a diagram showing a modification of the cross-sectional shape of the conductive wire arranged on the display device side. FIG. 14 is a diagram showing the measurement principle of the internal stress of the sample. FIG. 15 is a diagram illustrating the relationship between the internal stress and the amount of warpage of the main body layer and the low reflection layer. FIG. 16 is a diagram illustrating the relationship between the internal stress of the main body layer and the amount of warpage.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that, in the drawings attached to the present specification, for the sake of easy understanding of the drawings, the scale and the vertical / horizontal dimension ratio are appropriately changed and exaggerated from those of the actual ones.

<First Embodiment>
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS.

  First, with reference to FIG. 1, the transparent electrode 31 in this Embodiment is demonstrated. FIG. 1 is a plan view showing the transparent electrode 31 when viewed from the observer side.

  Here, an example in which the transparent electrode 31 is configured for a projection-type capacitively coupled touch panel will be described. Note that the “capacitive coupling” method is also referred to as “capacitance” method, “capacitance coupling” method, or the like in the technical field of the touch panel. It is treated as a term synonymous with the “capacitive coupling” method. A typical capacitive coupling type touch panel has a conductive pattern, and an external conductor (typically a human finger) approaches or touches the touch panel, whereby the external conductor and the touch panel are touched. A capacitor (capacitance) is formed with the conductive pattern. Based on the change in the electrical state accompanying the formation of the capacitor, the position coordinates of the position where the external conductor is approaching on the touch panel are specified.

  As shown in FIG. 1, the transparent electrode 31 includes a base film 32 and a plurality of conductive patterns 41 provided on the base film 32. As shown in FIG. 1, each conductive pattern 41 has a rectangular outline shape, and the long side of the rectangle extends in a strip shape in the vertical direction of FIG. The plurality of conductive patterns 41 are arranged at a constant arrangement pitch in a direction orthogonal to the direction in which each conductive pattern 41 extends. The arrangement pitch of the conductive patterns 41 is determined according to the resolution required for detecting the touch position, and is, for example, 1 mm to 5 mm.

  As shown in FIG. 1, the base film 32 of the transparent electrode 31 has a rectangular active area Aa1 extending from the central portion to the peripheral portion corresponding to the region where the touch position can be detected in the plan view. And a non-active area Aa2 having a rectangular frame shape located around the active area Aa1. The active area Aa1 and the inactive area Aa2 are respectively divided in accordance with the active area and the inactive area of the display device of the display device with a touch position detection function 10 described later.

  The conductive pattern 41 described above is disposed in the active area Aa1. Further, in the inactive area Aa2, a plurality of frame wirings 43 electrically connected to the respective conductive patterns 41 and a plurality of frame wirings arranged near the outer edge of the base film 32 and electrically connected to each frame wiring 43 are provided. Terminal portion 44.

  The frame wiring 43 and the terminal portion 44 connected to the conductive pattern 41 are provided for extracting a signal from the conductive pattern 41 to the outside of the transparent electrode 31. As long as signals can be appropriately transmitted, the specific configurations of the frame wiring 43 and the terminal portion 44 are not particularly limited. For example, the frame wiring 43 and the terminal portion 44 may be formed simultaneously with the conductive wire 51 with the same layer configuration as the conductive wire 51 described later.

  Next, the pattern shape of the conductive pattern 41 will be described with reference to FIG. 2A. 2A is a plan view showing a conductive pattern 41 in a portion surrounded by a one-dot chain line denoted by reference numeral II in FIG. As shown in FIG. 2A, the conductive pattern 41 is a conductive wire 51 having light shielding properties and electrical conductivity, and is composed of conductive wires 51 arranged in a mesh shape so that openings 51a are formed between the conductive wires 51. Has been.

  The ratio of the area occupied by the opening 51a (hereinafter referred to as the aperture ratio) in the total area of the conductive pattern 41 is sufficiently high, so that the image light from the display device can be transmitted through the transparent electrode 31 with an appropriate transmittance. As long as it can pass through the active area Aa1, the size and shape of the conducting wire 51 are not particularly limited. For example, in the example shown in FIG. 2A, the conductive pattern 41 is configured by arranging conductive wires 51 formed in a rectangular shape along a predetermined direction. The aperture ratio is appropriately set according to the characteristics of the image light emitted from the display device.

  The line width of the conducting wire 51 is set according to the required aperture ratio, the invisibility of the conductive pattern, etc. For example, the line width of the conducting wire 51 is in the range of 1 μm to 5 μm, more preferably in the range of 1 μm to 3 μm. More preferably, the average is set to 2 μm. Further, the arrangement pitch P1 of the conductive wires 51 extending in parallel with each other is also set according to the required aperture ratio or the like. For example, the arrangement pitch P1 of the conductive wires 51 is set within a range of 50 μm to 500 μm. . As a result, the influence of the conductive wire 51 on the image visually recognized by the observer can be reduced to a negligible level, that is, sufficient invisibility can be obtained.

  Although FIG. 2A shows an example in which the conductive pattern 41 is configured by arranging the conductive wires 51 whose opening portions are formed in a rectangular shape along a predetermined direction, the present invention is not limited thereto. . For example, as illustrated in FIG. 2B, the conductive pattern 41 may be configured by arranging the conductive wires 51 whose opening portions are formed in a rhombus shape along a predetermined direction. In this embodiment, as shown in FIGS. 2A and 2B, the number of openings 51a of the conductive pattern 41 is two in the direction orthogonal to the extending direction of the conductive pattern 41 (the left-right direction in the figure). However, the number of arrangements in the present invention is not limited to two, and the number is appropriately set according to the resolution of touch panel position detection, the sensitivity, the invisibility of the conductive pattern, and the like.

  Next, the layer configuration of the transparent electrode 31 will be described with reference to FIGS. 3 and 4. 3 is a cross-sectional view showing a case where the transparent electrode 31 is cut along the line III in FIG. 2A. FIG. 4 is an enlarged cross-sectional view showing the base film 32 and the conductive wire 51 shown in FIG. is there.

  As shown in FIG. 3, the transparent electrode 31 includes a transparent base film 32 having flexibility, and a conductive pattern 41 made of a conductive wire 51 provided on the surface of the base film 32. . In the present specification, “transparent” means that the light transmittance is sufficiently high and the other side can be seen through. Specifically, for example, the visible light transmittance is 50% or more, more preferably 80% or more, and still more preferably 90% or more. The total light transmittance is measured according to JIS K7361-1: 1997.

  The base film 32 can have a thickness of 50 μm or more and 100 μm or less, and further 70 μm or less. Such a thin base film 32 has excellent flexibility. Here, that a certain member has flexibility means that the target member is curved to the extent that a human can visually sense it. Such a base film 32 can be curved so as to form a three-dimensional curved surface. Therefore, extremely various design properties can be imparted to the base film 32.

  The base film 32 is for supporting patterns and wiring such as the conductive pattern 41 and the frame wiring 43 described above. As shown in FIG. 4, the base film 32 includes a transparent base material 33 that can transmit image light from the display device, and an acrylic resin provided between the transparent base material 33 and the conductive wire 51 of the conductive pattern 41. And a layer 34a. The base film 32 may further include an acrylic resin layer 34 b provided on the side of the transparent base material 33 opposite to the side facing the conductive wire 51.

  As a material constituting the transparent base material 33, a material having transparency and flexibility is used, and for example, a synthetic resin (plastic) is used. Examples of synthetic resins include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polypropylene (PP) and cycloolefin polymer (COP), polycarbonate (PC) resin, and triacetyl cellulose. A resin having flexibility and transparency such as a cellulose resin such as (TAC) is used.

  The acrylic resin layers 34a and 34b have a function of improving the scratch resistance against scratches that may be caused by friction with the guide roller when the transparent electrode 31 is manufactured by the roll-to-roll method, This is a layer provided to realize a function of adjusting optical characteristics such as transmittance and reflectance.

  As a material constituting the acrylic resin layers 34a and 34b, an acrylic resin is used. As the acrylic resin, those having sufficient scratch resistance and transparency are preferable. Typical examples of satisfying these conditions include ionizing radiation type acrylic resins that cure by a crosslinking reaction or a polymerization reaction by ionizing radiation irradiation. It is done. As such an ionizing radiation curable acrylic resin, a (meth) acrylate prepolymer or a (meth) acrylate monomer having a polymerizable functional group such as a (meth) acryloyl group or a (meth) acryloyloxy group in the molecule is used. It is done. Examples of the (meth) acrylate prepolymer include prepolymers such as urethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate. Examples of the (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentaerythritol hexa (meth) methacrylate. Examples include a polymer. (Here, “(meth) acryloyl group”, “(meth) acrylate” and the like mean “acryloyl group or methacryloyl group” and “acrylate or methacrylate”, respectively). These prepolymers and monomers are Depending on the required performance such as scratch resistance, flexibility, coating suitability, etc., one or more of the above prepolymers may be mixed as appropriate, and the above monomers may be used alone or in combination of two or more. Alternatively, one or more of the above prepolymers and one or more of the above monomers may be mixed and used. As the ionizing radiation, electromagnetic waves such as ultraviolet rays, visible rays, and X-rays, and charged particle beams such as electron beams and alpha rays can be used. When ultraviolet rays or visible rays are used as the ionizing radiation, 0.1 parts by mass to 5 parts by mass of a photoinitiator such as a benzotriazole compound or a benzophenone compound with respect to 100 parts by mass of the prepolymer and the monomer. Add about 1 part. Further, in order to improve the scratch resistance, fine particles having a particle size of 0.1 to 5 μm are added as fillers (fillers) in the acrylic resin. The fine particles include inorganic particles made of silica (silicon oxide), alumina (aluminum oxide), calcium carbonate, barium sulfate, etc., and organic particles such as acrylic resin, urethane resin, silicon resin, fluorine resin, melamine resin. Can be used. The addition amount of the fine particles can be about 0.1 to 30% by weight in the acrylic resin layer composition. The thickness of the acrylic resin layers 35a and 35b can be set to about 1 to 5 μm in a dry and cured state. In this embodiment, a cured product of an ultraviolet curable acrylic resin composition comprising an acrylate prepolymer, an acrylate monomer, and a benzotriazole photoinitiator is used.

  Of the acrylic resin layers 34a and 34b, the acrylic resin layer located on the observer side of the transparent base material 33 is referred to as an “observer side acrylic resin layer”, and the acrylic resin layer located on the opposite side. This may be referred to as “display device side acrylic resin layer”. As will be described later, the conducting wire 51 may be positioned on the viewer side of the base film 32 or may be positioned on the display device side of the base film 32. Therefore, the acrylic resin layer 34a may be an “observer side acrylic resin layer” and the acrylic resin layer 34b may be a “display device side acrylic resin layer”, or the acrylic resin layer 34b may be an “observer”. In some cases, the acrylic resin layer 34 a becomes a “display side acrylic resin layer”.

  Next, the layer structure of the conducting wire 51 will be described. As shown in FIG. 4, the conducting wire 51 includes a conducting wire forming layer 52 configured by arranging a low reflective layer 54, a main body layer 53, and a low reflective layer 55 in this order from the base film 32 side.

  The main body layer 53 is mainly a layer for realizing conductivity in the conductive wire 51. The main body layer 53 in the present invention is configured to have a thickness of, for example, 0.3 μm or less, more specifically within a range of 0.05 μm to 0.2 μm. Thereby, it can suppress that the thickness of the conducting wire 51 whole becomes large, and it can suppress that external light and video light are reflected in the side surface of the conducting wire 51 by this. For this reason, the visibility in the display device to which the transparent electrode 31 is attached can be sufficiently ensured.

On the other hand, reducing the thickness of the main body layer 53 can lead to an increase in the electrical resistance value of the conducting wire 51. Here, in the present embodiment, a metal material having a specific resistance equal to or lower than a desired value is used as a material constituting the main body layer 53. For example, the specific resistance is 4.0 × 10 ⁻⁶ (Ωm). The following metal materials are used. Thereby, the electrical resistance value of the conducting wire 51 can be made sufficiently low. For example, the sheet resistance value of the main body layer 53 can be set to 0.3Ω / □ or less. In the present invention, for example, the specific resistance is 3.0 × 10 ⁻⁸ as the metal material for constituting the main body layer 53 and having a specific resistance of 4.0 × 10 ⁻⁶ (Ωm) or less. A material (metal simple substance, metal alloy, etc.) containing 90% by weight or more of a metal such as gold, silver, copper, and aluminum that is (Ωm) or less can be used. In the present embodiment, a material containing 99.9% by weight of copper can be used.

  By the way, metal materials, such as copper, show a metallic luster, while having high electroconductivity. For this reason, when an untreated metal material is used as the conducting wire 51, the visibility of the image light from the display device is hindered by the metallic luster of the conducting wire. In particular, copper exhibits a reddish color peculiar to copper, so that it is more conspicuous than other metal materials such as silver, and this hinders the visibility of image light from the display device.

  In order to relieve such metallic luster peculiar to copper, a thin low-reflection layer 54 and a low-reflection layer 55 whose metallic luster is suppressed compared to the main body layer 53 are arranged on both sides of the main body layer 53. Hereinafter, the low reflection layers 54 and 55 will be described.

  The low reflection layers 54 and 55 are both layers made of copper nitride. Copper nitride may further contain oxygen atoms. As the copper nitride, for example, a copper compound containing 5 to 25 atomic% of nitrogen, 5 to 25 atomic% of oxygen, and 50 to 90 atomic% of copper may be used. In the low reflection layers 54 and 55 configured using such copper nitride, the metallic luster is reduced as compared with the metallic luster in the main body layer 53, and in particular, it has a reddish color peculiar to copper. The color has been reduced. For this reason, it can suppress that the visibility of an image | video falls by the reflected light from the conducting wire 51. FIG.

  Moreover, since both the low reflection layers 54 and 55 have a thickness smaller than that of the main body layer 53, specifically, both have a thickness in the range of 10 nm to 60 nm, the thickness of the entire conductive wire 51 is increased. This can be suppressed. Thereby, it can suppress that external light and image light are reflected in the side surface of the conducting wire 51. FIG.

  Moreover, the reflectance of the light in the conducting wire 51 can also be lowered by setting the thicknesses of both the low reflection layers 54 and 55 within the range of 10 nm to 60 nm. As this reason, the thin film interference which arises in the low reflection layers 54 and 55 can be mentioned, for example. The thin film interference is a phenomenon in which light reflected on one surface of the low reflection layers 54 and 55 interferes with light reflected on the other surface of the low reflection layers 54 and 55. By setting the thicknesses of the low reflection layers 54 and 55 within the above-mentioned range of 10 nm to 60 nm, thin film interference is generated such that the reflected lights reflected on the respective surfaces weaken each other. It can be considered that the reflectivity of is reduced.

  The method for forming the conductive wire forming layer 52 as described above is not particularly limited, and a known thin film forming method such as a sputtering method, a vacuum evaporation method, a CVD method, an ion plating method, or an electron beam evaporation method is used. be able to. For example, when the sputtering method is used as a method for forming the low reflection layers 54 and 55, while supplying nitrogen gas or both nitrogen gas and oxygen gas controlled to a predetermined flow rate in a vacuum atmosphere containing Ar gas. By applying discharge power to a target made of copper, a layer made of the above-mentioned copper nitride having a desired composition can be obtained.

  By the way, as mentioned in the column of the problem to be solved by the invention, when the conductor forming layer 52 is formed by the sputtering method, high energy particles such as recoil Ar atoms are taken into the conductor forming layer 52. In some cases, internal stress (tensile stress or compressive stress) may appear in the conductive wire forming layer 52. In order to increase the flexibility of the wiring board, it is necessary to reduce the thickness of the base film 32 of the material as exemplified above to the thickness as described above, but the conductive wire forming layer 52 is formed on the thin base film 32. If formed, the laminated body 60 of the base film 32 and the conductive wire forming layer 52 may be warped due to internal stress of the conductive wire forming layer 52. When warpage occurs in the stacked body 60, it becomes extremely difficult to form a fine conductive pattern by a photolithography method in a subsequent process.

  As a result of intensive studies in consideration of such problems, the present inventors have determined that the tensile internal stress of the main body layer 53 is measured using an X-ray diffraction method (hereinafter referred to as an XRD (X-ray diffraction) method). Is within the range of −130 MPa or more and 20 MPa or less, it is sufficient that even if the conductive wire forming layer 52 is formed on the thin base film 32, the laminate 60 is warped by the internal stress of the conductive wire forming layer 52. It was confirmed that it can be suppressed. Below, the relationship between the tensile internal stress of the main body layer 53 and the low reflection layers 54 and 55 and the amount of warpage of the laminate 60 will be described in detail.

  First, a method for evaluating the internal stress of a sample using the XRD method will be described. FIG. 14 is a diagram showing the measurement principle of the internal stress of the sample. As shown in FIGS. 14A to 14C, when a tensile internal stress is present in a sample, for example, the lattice plane spacing of crystal grains in the sample is not uniform. Specifically, as shown in FIGS. 14A to 14C, the crystal plane spacing increases as the crystal grain has a larger angle ψ formed by the normal N of the lattice plane and the normal N ′ of the sample plane. It is increasing. The degree to which the lattice spacing increases is proportional to the magnitude of the internal stress. Therefore, the internal stress σ can be obtained by measuring the lattice spacing for a plurality of angles Ψ and applying the following equation to this measurement result. it can. In the following formula, the lattice spacing corresponds to the diffraction angle (2θ).

σ = −E / {2 (1 + ν)} · cot θ ₀ · (π / 180) · {Δ (2θ) / Δ (sin ² ψ)}
= K · Δ (2θ) / Δ (sin ² Ψ)
Here, σ is internal stress, E is Young's modulus, ν is Poisson's ratio, and θ ₀ is standard Bragg angle. K is a constant determined by the material and the measurement wavelength. That is, the relationship between the diffraction angle (2θ) and sin ² Ψ is plotted on a graph, the gradient of the approximate straight line obtained by applying the least square method to this plot is obtained, and this is multiplied by K. The internal stress can be evaluated.

  In the present embodiment, when the conductor forming layer 52 is formed on the base film 32, copper nitride is formed by sputtering on the base film 32 in a state where Ar having the pressure shown in Table 1 below is introduced into the chamber. Three layers of (low reflection layer 54), copper (main body layer 53) and copper nitride (low reflection layer 55) were formed in this order. And about each of three types of samples prepared in this way, each internal stress of the low reflection layers 54 and 55 and the main body layer 53 was evaluated using the XRD method. In the present embodiment, the internal stress of copper constituting the main body layer 53 is evaluated based on the diffracted light from the 311 plane of the crystal lattice, and the internal stress of copper nitride constituting the low reflection layers 54 and 55 is 220 of the crystal lattice. Evaluation was based on diffracted light from the surface. This is because when the internal stress is generated in the copper, the shift of the peak position of the diffracted light by the 311 plane of the copper crystal lattice is remarkable, and when the internal stress is generated in the copper nitride, the crystal of the copper nitride This is because the peak position of the diffracted light is remarkably shifted by the 220 plane of the grating, and the internal stress of the main body layer 53 and the low reflection layers 54 and 55 can be evaluated with high accuracy by paying attention to these planes. Of course, in principle, the internal stress can also be evaluated using diffracted light from another surface such as the 111-plane of copper.

  FIG. 15 is a diagram showing the relationship between the internal stress evaluation results of the three types of samples and the amount of warpage of each sample. In FIG. 15, three rhombus plots connected by broken lines show the tensile internal stress of copper nitride (low reflection layers 54 and 55) of each sample, and three square plots connected by broken lines are The tensile internal stress of copper (main body layer 53) is shown. In addition, three triangular plots connected by solid lines indicate the amount of warpage of each sample. For each of the three diamond plots, square plots, and triangle plots, the plot located on the left side of the figure corresponds to sample 1 and the plot located in the center corresponds to sample 2. The plot located on the right side corresponds to sample 3. In this specification, the amount of warping refers to the highest point and the lowest point of the height of the upper surface of the sample piece when a sample piece of a square laminate having a side of 10 cm is placed on the flat plate stage. Means the difference.

  As shown in FIG. 15, the internal stress of copper nitride (low reflection layers 54 and 55) does not change greatly even when the film forming pressure when forming the copper nitride is increased. On the other hand, the internal stress of copper (main body layer 53) tends to increase as the film formation pressure is increased when copper nitride is formed. Further, the amount of warpage of each sample tends to decrease as the tensile internal stress of copper (main body layer 53) increases (when the compressive internal stress decreases). Quantitatively, the correlation coefficient between the internal stress and the amount of warpage of copper nitride (low reflection layers 54 and 55) of each sample is −0.353, and the internal stress of copper (main body layer 53) of each sample is The correlation coefficient with the amount of warpage is 0.950. That is, it can be said that the amount of warpage of each sample substantially depends on the internal stress of the main body layer 53.

Next, FIG. 16 is a diagram showing the relationship between the evaluation result of the internal stress of the main body layer 53 and the warpage amount, with the internal stress (MPa) as the horizontal axis and the warpage amount (mm) of the sample as the vertical axis. The straight line in the figure is an approximate straight line obtained by applying the least square method to each plot. This approximate straight line is expressed by the following equation where the amount of warpage is Y (mm) and the internal stress of the main body layer 53 is X (MPa).
Y = 0.0674X + 3.70445 (1)

  In general, the amount of warp of the sample is preferably in the range of −5 mm to 5 mm. When the range of the internal stress X corresponding to the range of the warp amount is obtained based on the equation (1), a range of −130 MPa to 20 MPa is obtained. The negative internal stress represents a compressive stress, and the positive internal stress represents a tensile stress.

  However, as will be understood from the relationship between the film forming pressure of copper nitride (low reflection layers 54 and 55) and the internal stress of copper (main layer 53), for example, the amount of warping of the sample is set to around 0 mm (main layer 53). In order to set the internal stress of the copper nitride to around 0 MPa, the film forming pressure of copper nitride needs to be higher than 4.0 Pa. On the other hand, in order to keep the inside of the chamber of the sputtering apparatus clean, it is preferable that the film forming pressure is low. In view of such circumstances, in manufacturing the transparent electrode 31 according to the present embodiment, 4.0 Pa was adopted as the film forming pressure of copper nitride, but a problem such as contamination of the environment in the chamber was not confirmed. In addition, the internal stress of the main body layer 53 at this time was −53 MPa (see FIG. 15).

  Next, a method for manufacturing the transparent electrode 31 having the above configuration will be described with reference to FIGS. 5A to 5E.

  First, as shown in FIG. 5A, a transparent base film 32 having flexibility is prepared. As described above, the base film 32 includes the transparent base material 33 and the acrylic resin layers 34a and 34b provided on both sides of the transparent base material 33, respectively.

  An example of a method for producing the substrate film 32 will be described. First, a long transparent substrate 33 is prepared, and acrylic resin layers 34 a and 34 b are formed on both sides of the transparent substrate 33. For example, the acrylic resin layers 34a and 34b can be formed by coating a coating liquid containing an acrylic resin on the transparent substrate 33 using a coater. At this time, as the coater, a coater that can sufficiently ensure the flatness of the acrylic resin layers 34a and 34b is preferably used. For example, a gravure roll coater is used. The coating liquid for forming the acrylic resin layers 34a and 34b may contain a leveling agent for improving the flatness of the acrylic resin layers 34a and 34b. Thereby, for example, it is possible to suppress the occurrence of defects such as pinholes when the conductive wire 51 layer is formed on the acrylic resin layer 34a.

  The base film 32 can have a thickness of 50 μm or more and 100 μm or less, and further 70 μm or less. Such a thin base film 32 has excellent flexibility.

  After preparing the base film 32, as shown to FIG. 5B, the low reflection layer 54 is formed on the acrylic resin layer 34a. The low reflective layer 54 can be formed by sputtering a copper target using AC discharge and / or DC discharge while supplying nitrogen gas into a vacuum atmosphere containing 4 Pa of Ar gas. As the frequency of AC discharge, for example, 30 kHz to 2 MHz can be adopted. In addition to nitrogen gas, oxygen gas may be further supplied.

  Next, as shown in FIG. 5B, the main body layer 53 is formed on the low reflection layer 54. The main body layer 53 can be formed by sputtering a copper target using AC discharge and / or DC discharge in a vacuum atmosphere containing 0.6 Pa Ar gas. As the frequency of AC discharge, for example, 30 kHz to 2 MHz can be adopted.

  Next, as shown in FIG. 5B, the low reflection layer 55 is formed on the main body layer 53. The low reflection layer 55 can be formed under the same conditions as the low reflection layer 54.

  Thus, the laminated body 60 (also called a blank) provided with the base film 32 and the conductive wire forming layer 52 provided on the base film 32 as a base material for producing the transparent electrode 31. Is obtained. The conductive wire forming layer 52 includes a low reflection layer 54, a main body layer 53, and a low reflection layer 55 arranged in this order from the base film 32 side. As described above, the tensile internal stress of the main body layer 53 of the present embodiment was measured by the XRD method, and was −53 MPa. Moreover, the amount of warpage of the laminate 60 was 2 mm.

  After preparing the laminated body 60, as shown in FIG. 5C, a photosensitive resist layer 71 is formed in a predetermined pattern on the conductive wire forming layer 52. The photosensitive resist layer 71 has photosensitivity to light in a specific wavelength range, for example, ultraviolet rays. The type of the photosensitive resist layer 71 is not particularly limited. For example, a photodissolvable photosensitive resist layer may be used, or a photocurable photosensitive resist layer may be used. Here, an example in which a photodissolvable photosensitive resist layer is used will be described.

  The photosensitive resist layer 71 is formed in a pattern corresponding to the pattern of the conductive wire 51. The photosensitive resist layer 71 is, for example, by first coating a photosensitive resist material on the surface of the laminate 60 using a coater, and then exposing and developing the photosensitive resist material in a predetermined pattern. A photosensitive resist layer 71 having a predetermined pattern shape is formed.

  Here, according to the present embodiment, since the warpage of the multilayer body 60 is sufficiently suppressed, a part of the multilayer body 60 does not substantially float from the stage during exposure, and the photosensitive body The fine pattern shape of the conductive resist layer 71 can be stably formed.

  Next, as shown in FIG. 5D, the low reflection layers 54 and 55 and the main body layer 53 are etched using the photosensitive resist layer 71 as a mask. Note that, as described above, each of the low reflection layers 54 and 55 and the main body layer 53 includes copper. For this reason, the low reflection layers 54 and 55 and the main body layer 53 can be simultaneously etched using an etching solution capable of dissolving copper. As the etching solution, for example, phosphonitrate is used.

  Next, the photosensitive resist layer 71 remaining on the main body layer 53 is washed with a chemical solution for dissolving and removing the photosensitive resist layer 71 and subjected to film removal. Thereby, as shown in FIG. 5E, the photosensitive resist layer 71 can be removed. In this way, the conductive wire forming layer 52 having the low reflection layers 54 and 55 and the main body layer 53 can be patterned, and the transparent electrode 31 including the conductive wire 51 formed therefrom can be obtained.

  As described above, according to the present embodiment, since the tensile internal stress of the main body layer 53 measured using the XRD method is −53 MPa, the lead wire forming layer 52 in the laminate 60 having excellent flexibility. It is possible to sufficiently suppress the warp of the base film 32 due to the internal stress. Therefore, a part of the laminated body 60 does not substantially float from the stage during exposure, and the fine pattern shape of the photosensitive resist layer 71 can be stably formed. As a result, in the transparent electrode 31 having excellent flexibility, it is possible to achieve sufficient thinning of the conductive wire 51.

  Further, according to the present embodiment, the conductive wire 51 faces the base film 32 in the surface of the main body layer 53 in addition to the low reflection layer 54 provided between the main body layer 53 and the base film 32. A low reflection layer 55 provided on the surface opposite to the surface is included. For this reason, the occurrence of light reflection can be suppressed on both sides of the main body layer 53. Thereby, it is possible to sufficiently ensure the visibility of the video.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a display device with a touch position detection function obtained by combining a touch panel including the above-described transparent electrode 31 and a display device will be described. In the present embodiment, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, when it is clear that the operational effects obtained in each embodiment can be obtained also in this embodiment, the description thereof may be omitted.

  FIG. 6 is a development view showing the display device 10 with a touch position detection function. As shown in FIG. 6, the display device 10 with a touch position detection function is configured by combining a touch panel 30 and a display device 15 such as a liquid crystal display or an organic EL display.

  The illustrated display device 15 is configured as a flat panel display. The display device 15 includes a display panel 16 having a display surface 16 a and a display control unit (not shown) connected to the display panel 16. The display panel 16 includes an active area A1 that can display an image, and an inactive area (also referred to as a frame area) A2 that is disposed outside the active area A1 so as to surround the active area A1. . The display control unit processes information regarding the video to be displayed, and drives the display panel 16 based on the video information. The display panel 16 displays a predetermined image on the display surface 16a based on a control signal from the display control unit. That is, the display device 15 plays a role as an output device that outputs information such as characters and drawings as video.

  As shown in FIG. 6, a protective plate 12 having translucency may be further provided on the viewer side of the touch panel 30, that is, the side opposite to the display device 15. For example, the protective plate 12 is bonded to the surface of the touch panel 30 on the viewer side with an adhesive layer or the like. The protective plate 12 is for preventing damage to the pattern of the touch panel 30 and the display device 15 due to contact with an external conductor such as a finger, and is also referred to as a so-called front plate.

  As shown in FIG. 6, the touch panel 30 is bonded to the display surface 16 a of the display device 15 via, for example, an adhesive layer (not shown). The touch panel 30 is configured by combining two transparent electrodes 31. In FIG. 6, the see-through electrode arranged on the observer side is represented by reference numeral 31 </ b> A, and the see-through electrode arranged on the display device side from the see-through electrode 31 </ b> A is represented by reference numeral 31 </ b> B. In the following description, the transparent electrode labeled 31A is also referred to as a first transparent electrode 31A, and the transparent electrode labeled 31B is also referred to as a second transparent electrode 31B.

  FIG. 7 is a plan view showing the touch panel 30 when viewed from the observer side. In FIG. 7, the constituent elements of the first transparent electrode 31A are represented by solid lines, and the constituent elements of the second transparent electrode 31B are represented by dotted lines.

  As shown in FIG. 7, each of the first transparent electrode 31A and the second transparent electrode 31B includes a plurality of conductive patterns 41 extending in a predetermined direction. Here, the first transparent electrode 31A and the second transparent electrode 31B are arranged so that the respective conductive patterns 41 extend in directions intersecting each other. For example, the first transparent electrode 31A is arranged such that the conductive pattern 41 extends along the first direction D1. On the other hand, the 2nd transparent electrode 31B is arrange | positioned so that the conductive pattern 41 may extend along the 2nd direction D2 orthogonal to the 1st direction D1.

  FIG. 8 is an enlarged plan view showing the conductive pattern 41 in the portion surrounded by the alternate long and short dash line with the symbol XVI in FIG. As shown in FIG. 8, the conductive pattern 41 of the first transparent electrode 31A and the conductive pattern 41 of the second transparent electrode 31B are each composed of a conductive wire 51 arranged in a mesh shape.

  FIG. 9 is a cross-sectional view showing a case where the touch panel 30 is cut along the line XVII in FIG. As shown in FIG. 9, the touch panel 30 has the first perspective view so that both the lead wire 51 of the first transparent electrode 31 </ b> A and the lead wire 51 of the second transparent electrode 31 </ b> B are located on the display device side of the base film 32. 31A and the second transparent electrode 31B are combined. Note that an adhesive layer 38 or the like may be interposed between the first transparent electrode 31A and the second transparent electrode 31B.

  10 is an enlarged cross-sectional view of a part of the touch panel 30 shown in FIG. As shown in FIG. 10, both the conductive wire 51 of the first transparent electrode 31 </ b> A and the conductive wire 51 of the second transparent electrode 31 </ b> B include the above-described conductive wire forming layer 52. Here, as shown in FIG. 10, the conductive wire forming layer 52 includes a main body layer 53, a low reflection layer 54 provided on the observer side of the main body layer 53, and a low reflection provided on the display device side of the main body layer 53. Layer 55.

  Since the low reflection layer 54 is provided on the viewer side of the main body layer 53, it is possible to prevent external light incident on the touch panel 30 from the viewer side from being reflected by the conductive wire 51 and returning to the viewer side. it can. Thereby, it can suppress that the conducting wire 51 is visually recognized by an observer, and this can suppress that the visibility of the image from the display device 15 is hindered by the conducting wire 51.

  Further, as described above, the main body layer 53 of the conductive wire forming layer 52 is configured to have a thickness of 0.3 μm or less. In the present embodiment, it is 0.1 μm. For this reason, it can suppress that the light which injected into the touch panel 30 along the direction inclined from the normal line direction of the base film 32 is reflected by the side surface of the conducting wire formation layer 52. Thereby, it can suppress that the side of the conducting wire 51 is visually recognized by an observer, and that the video light from the display device is hindered by the side of the conducting wire 51. Accordingly, the visibility of the video can be improved.

  Further, since the conductive wire forming layer 52 includes a low reflection layer 55 provided on the display device side of the main body layer 53, the image light from the display device 15 incident on the touch panel 30 is reflected by the conductive wire 51 and displayed. Returning to the 15 side, it is possible to prevent the light from being reflected again by the components of the display device 15 and reaching the observer as noise light.

  Various changes can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as the above embodiment. The duplicated explanation is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

  FIG. 10 shows an example in which both the conductive wire 51 of the first transparent electrode 31 </ b> A and the conductive wire 51 of the second transparent electrode 31 </ b> B include the conductive wire forming layer 52. However, the present invention is not limited to this, and the conducting wire 51 of the first transparent electrode 31A may include the conducting wire forming layer 52B described above. That is, the conducting wire 51 of the first transparent electrode 31A may be configured by either the conducting wire forming layer 52 or the conducting wire forming layer 52B. Similarly, the conducting wire 51 of the second transparent electrode 31B may be constituted by either the conducting wire forming layer 52 or the conducting wire forming layer 52B.

  FIG. 9 shows an example in which both the conductive wire 51 of the first transparent electrode 31A and the conductive wire 51 of the second transparent electrode 31B are located on the display device side of the base film 32, but this is not limitative. There is nothing. For example, as shown in FIG. 11, the conducting wire 51 of the first transparent electrode 31A is located on the viewer side of the base film 32, while the conducting wire 51 of the second transparent electrode 31B is an indication of the base film 32. It may be located on the device side.

  As shown in FIG. 12, the conductive wire 51 of the first transparent electrode 31 </ b> A is located on the display device side of the base film 32, while the conductive wire 51 of the second transparent electrode 31 </ b> B is an observation of the base film 32. It may be located on the person side.

  Next, a preferable example of the cross-sectional shape of the conducting wire 51 when the conducting wire 51 is provided on the display device side of the base film 32 will be described with reference to FIG.

  As shown in FIG. 13, the conductive wire forming layer 52 of the conductive wire 51 has a tapered shape that tapers toward the display device 15. In this case, the external light L incident on the touch panel 30 along the direction inclined from the normal direction of the base film 32 is not incident on the side surface of the conductor 51 due to the tapered shape of the conductor formation layer 52. You can escape to the side. For this reason, it can further suppress that external light is reflected by the conducting wire 51 and returns to the observer side.

  Although the specific taper shape of the conducting wire formation layer 52 is appropriately set according to the assumed degree of inclination of external light, for example, the normal direction of the base film 32 and the side surface of the conducting wire 51 are formed. The angle is in the range of 10 ° to 30 °.

  In addition, although the some modification with respect to this Embodiment mentioned above has been demonstrated, naturally, it can also apply combining a some modification suitably.

DESCRIPTION OF SYMBOLS 10 Display device with a touch position detection function 12 Protection plate 15 Display device 16 Display panel 30 Touch panel 31 Transparent electrode 32 Base film 33 Transparent base material 34a, 34b Acrylic resin layer 34a1, 34b1 First acrylic resin layer 34a2, 34b2 Second acrylic resin layer 38 Adhesive layer 41 Conductive pattern 43 Frame wiring 44 Terminal portion 51 Conductive wire 52 Conductive wire forming layer 53 Main body layer 54 Low reflective layer 55 Low reflective layer 60 Laminate 71 Photosensitive resist layer

Claims (4)

A transparent base film having flexibility;
A conductor forming layer provided on the base film;
With
The conducting wire forming layer is
A body layer made of copper;
A low reflection layer made of copper nitride, disposed between the main body layer and the substrate film;
A second low reflection layer made of copper nitride disposed on the opposite side of the main reflection layer from the low reflection layer;
Including
The laminated body whose tensile internal stress of the said main body layer measured using a X ray diffraction method exists in the range of -130 Mpa or more and 20 Mpa or less. A transparent base film having flexibility;
A plurality of conductive patterns provided on the base film;
With
The conductive pattern is a conductive wire having a light shielding property, and is composed of conductive wires arranged in a mesh shape so that an opening is formed between the conductive wires,
The conducting wire is
A body layer made of copper;
A low reflection layer made of copper nitride, disposed between the main body layer and the substrate film;
A second low reflection layer made of copper nitride disposed on the opposite side of the main reflection layer from the low reflection layer;
Including
The transparent electrode whose tensile internal stress of the said main body layer measured using a X ray diffraction method exists in the range of -130 Mpa or more and 20 Mpa or less.   A touch panel comprising the transparent electrode according to claim 2. A display device;
The touch panel according to claim 3, which is disposed on a display surface of the display device,
A display device with a touch position detection function.