JP5267403B2 - Electrode film for touch panel, method for producing electrode film for touch panel, and touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode film for a touch panel capable of reducing haze at low cost, and to provide a method of manufacturing the electrode film and the touch panel using the electrode film. <P>SOLUTION: The electrode film for the touch panel is configured such that an electrode consisting of an aluminum pattern layer having a plurality of openings and a line section surrounding and dividing this is formed through a transparent adhesive layer on one face of a transparent base material, and the rate (R<SB>SCE</SB>/R<SB>SCI</SB>) of a diffused light beam reflection rate (R<SB>SCE</SB>) for a full light beam reflection rate (R<SB>SCI</SB>) measured based on the JIS Z 8722 of the transparent adhesive layer side surface of the aluminum pattern layer is &le;0.4. The method of manufacturing the electrode film is also provided along with the touch panel using the electrode film. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a touch panel disposed on a screen of a display device or the like, an electrode film used for the touch panel, and a method for manufacturing the electrode film.

  The touch panel is used as an input device mounted on a screen of a display device such as a liquid crystal display or a plasma display. Capacitance type, optical type, ultrasonic type, thin film resistance type, etc. have been proposed as the touch panel type depending on the input position detection method, but especially the thin film resistance type touch panel has a simple structure and detection method. It is widely used because it is. A general thin film resistance type touch panel includes two electrode films having a transparent conductive film such as ITO formed on the surface, and an insulating spacer formed on one of the transparent conductive film sides of the electrode film. Provided, the transparent conductive films of the respective electrode films are opposed to each other, and are configured to be spaced apart from each other by the spacer.

A conventional thin film resistance type touch panel is formed with a transparent conductive film such as ITO. However, the transparent conductive film is brittle and may be cracked or peeled off due to bending or the like. There was a problem that sex could not be obtained. Further, the conventional thin film resistance type touch panel has a problem of improving the light transmittance.
With respect to these problems, in Patent Document 1, an electrode film that does not use a transparent conductive film, specifically, a lattice network-like opening pattern is formed with a resist film, and the opening network is formed with a lattice network-like shape by electroless plating. An electrode film formed with a metal film has been proposed.
Since the metal film has a lattice network-like opening pattern, flexibility is imparted to the metal film, so that the problem of cracking due to bending or the like and the problem of peeling can be solved. However, the growth rate of the metal film by electroless plating is low, and the problem remains that the production rate (production efficiency) is low.

  In response to these problems, Patent Document 2 proposes an electrode film that has improved light transmittance by providing a missing portion in a transparent conductive film formed on a substrate.

  There has also been proposed a touch panel sheet (electrode film) in which a metal wiring pattern (metal pattern layer) made of a metal such as copper is formed on a transparent substrate such as a resin film (for example, Patent Document 3).

JP 2004-192093 A Japanese Patent Laid-Open No. 10-326152 JP 2008-305036 A

  The metal pattern layer is formed in a mesh shape by laminating an unprocessed metal foil on a transparent substrate via a transparent adhesive layer, and then etching the metal foil by a photolithography method. In the electrode film obtained in this way, the surface of the transparent adhesive layer onto which the fine irregularities on the surface of the metal foil are transferred is exposed in the opening from which the metal foil has been removed by etching. There is a problem that light is easily scattered on the uneven surface of the agent layer, the electrode film becomes opaque, and haze increases.

In recent years, there is a demand for cost reduction along with reduction in haze of electrode films.
As a material of the metal foil used for the metal pattern layer of the electrode film, generally copper (copper foil) has been widely used. However, the use of the copper foil increases the cost. Therefore, in order to reduce the cost, it is conceivable to use a material that is less expensive than the copper foil.

  The present invention has been made in view of the above problems, and provides an electrode film for a touch panel that can reduce haze and is inexpensive, a method for producing the electrode film, and a touch panel using the electrode film. The purpose is to do.

The inventors of the present invention studied to manufacture an electrode film for a touch panel using aluminum (aluminum thin film) that is cheaper than copper as a material for a metal foil used for a metal pattern layer. In the production process, the aluminum thin film is formed by superposing two aluminum foils and extending the aluminum foil with a rolling roll. At that time, the surface in contact with the rolling roll is shaped as a smooth surface of the rolling roll, so this surface is called a mirror surface, while the surface in contact with the aluminum foils has minute irregularities whose surface is messy due to stochastic fluctuations. Therefore, this surface is called a rough surface. Therefore, the aluminum thin film has a mirror surface and a rough surface.
Further, as a result of the experiments by the present inventors, even when the arithmetic average roughness Ra or the ten-point average roughness Rz, which has been conventionally used as a general index representing the uneven shape on the surface of the metal foil, is defined, It was found that haze cannot always be reduced.
Therefore, as a result of intensive studies, the present inventors faced the mirror surface (smooth surface with low light scattering property) of an aluminum thin film having a specific index within a specific range with the transparent substrate side. Thus, the haze of the obtained electrode film for a touch panel is reduced, and the present invention has been completed.
That is, the electrode film for a touch panel according to the present invention is an electrode composed of an aluminum pattern layer having a plurality of openings and a line portion surrounding and partitioning it on one surface of the transparent substrate with a transparent adhesive layer interposed therebetween. It is provided, and the ratio _{(R SCE} of total light reflectance was measured in conformity with JIS Z 8722 of the transparent adhesive layer side surface of the aluminum pattern layer diffuse light reflectance for _{(R SCI) (R SCE)} / R _SCI ) is 0.4 or less.

The electrode film for a touch panel of the present invention is such that the surface on the transparent substrate side of the aluminum pattern layer is a smooth surface (mirror surface) having a low light scattering property (by selecting such a surface of the aluminum thin film), diffuse light reflectance to the total light reflectance of the transparent adhesive layer surface of the opening portion of the aluminum pattern layer _{(R SCI)} the ratio of _{(R SCE) (R SCE /} R SCI) can be the above specific range, Since the transparent adhesive layer surface has a shape that hardly scatters light, haze can be reduced.

Moreover, the manufacturing method of the electrode film for touchscreens which concerns on this invention is for touchscreens provided with the electrode which consists of an aluminum pattern layer which has a several opening part and the line part which encloses and partitions this on one surface of a transparent base material. A method for producing an electrode film,
(I) An aluminum thin film having a surface having a diffused light reflectance ( _RSCE ) ratio ( _RSCE / _RSCI ) of 0.4 or less to the total light reflectance ( _RSCI ) measured according to JIS Z 8722 The process to prepare,
(Ii) A step of laminating the aluminum thin film on one surface of the transparent substrate with the surface of which R _SCE / R _SCI is 0.4 or less facing the transparent substrate via a transparent adhesive layer And (iii) a step of etching the aluminum thin film into a predetermined pattern shape to form an electrode.

According to the manufacturing method of the electrode film for touch panels of this invention, the cost reduction of an electrode film can be achieved by using aluminum cheaper than copper as a material of the metal foil used for a metal pattern layer.
Further, on one surface of a transparent substrate, through a transparent adhesive layer, a ratio of the diffuse light reflectance to the total light reflectance of the aluminum thin film _{(R SCI) (R SCE)} (R SCE / R SCI) is the with light scattering of less smooth surface which is a specific range (mirror), the total light reflectance of the transparent adhesive layer side surface of the aluminum pattern layer (R _SCI) diffuse light reflectance for the (R _SCE) The ratio ( _RSCE / _RSCI ) can be in a specific range. Furthermore, by laminating this facing the transparent base material, the surface of the transparent adhesive layer in the opening after the etching treatment of the aluminum thin film also has a shape that hardly scatters light, thereby reducing haze. An electrode film can be obtained.

Moreover, the touch panel according to the present invention is a touch panel in which two electrode films having transparent conductive electrodes on one surface of a transparent substrate are arranged with electrodes facing each other via a spacer,
Of the two electrode films, at least one of the electrode films is the electrode film for a touch panel according to the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, providing the touch panel which can reduce a haze at low cost by using the electrode film for touch panels which concerns on this invention for at least one electrode film among the two electrode films of a touch panel. it can.

According to the touch panel electrode film of the present invention, the particular spreading light reflectance to the total light reflectance of the surface of the transparent substrate side of the aluminum pattern layer _{(R SCI)} the ratio of _{(R SCE) (R SCE /} R SCI) By setting it as the range, the transparent adhesive layer surface at the opening of the aluminum pattern layer can be a smooth surface (mirror surface) with low light scattering property, and the transparent adhesive layer surface is less likely to be light scattered. Therefore, haze can be reduced.

Moreover, according to the manufacturing method of the electrode film for touchscreens of this invention, the cost reduction of an electrode film can be achieved by using aluminum cheaper than copper as a material of the metal foil used for a metal pattern layer.
Further, on one surface of a transparent substrate, through a transparent adhesive layer, a ratio of the diffuse light reflectance to the total light reflectance of the aluminum thin film _{(R SCI) (R SCE)} (R SCE / R SCI) is the By laminating a smooth surface (mirror surface) with a low light scattering property in a specific range so as to face the transparent substrate, the surface of the transparent adhesive layer in the opening after etching of the aluminum thin film is subjected to light scattering. Since it is difficult to form, an electrode film with reduced haze can be obtained. Further, a smooth surface (mirror surface) having a low light scattering property of the aluminum thin film is laminated on one surface of the transparent base material through the transparent adhesive layer so as to face the transparent base material. Intrusion of bubbles between the transparent adhesive layer is suppressed, and an increase in haze due to light scattering of residual bubbles can also be suppressed.

  Moreover, the touch panel which can reduce a haze can be provided at low cost by using the electrode film for touch panels which concerns on this invention for the at least one electrode film of a touch panel.

It is sectional drawing which showed typically an example of the electrode film for touchscreens which concerns on this invention. It is sectional drawing which showed typically another example of the electrode film for touchscreens which concerns on this invention. It is sectional drawing which showed typically the touch panel which has arrange | positioned the electrode film for touch panels shown in FIG. 2 as an electrode film of an input side, and has arrange | positioned the electrode film for touch panels shown in FIG. 1 as an electrode film on the side of a display apparatus. It is sectional drawing which showed typically the touch panel which has arrange | positioned the electrode film for touch panels shown in FIG. 2 as an electrode film of an input side.

The present invention includes an electrode film for a touch panel (hereinafter, also simply referred to as an electrode film), a manufacturing method thereof, and a touch panel using the electrode film. Each will be described in detail below.
Incidentally, the terms “rough surface” and “mirror surface” in the present invention are definitions of the industry terms of the metal foil manufacturer. Among the outer surfaces (front and back surfaces) of the aluminum foil, the surface of the metal foil manufacturer Applying physical or chemical treatment to increase the degree of unevenness of the surface, the surface with the relatively increased degree of unevenness is referred to as “roughened surface” (others, “roughened surface” or “matte surface”). Both) On the other hand, the surface on the other side is referred to as “mirror surface” (also referred to as “smooth surface”, “glossy surface”, or “mirror surface”).
Incidentally, these “rough surface” and “mirror surface” are scales that have been formed and evaluated from the viewpoint of the adhesive force by the throwing effect, and as described later, these “rough surface” or “mirror surface” are not necessarily bonded. It does not always correlate directly with the haze value in the state of being transferred and shaped on the surface of the agent layer. Moreover, it turns out that it does not correlate with the numerical range of the specific light reflectance ratio ( _RSCE / _RSCI ) prescribed | regulated by this invention.
In the present invention, an aluminum foil is used as the aluminum thin film laminated on one surface of the transparent substrate.

I. An electrode film for a touch panel according to the present invention has an aluminum pattern layer having a plurality of openings and a line portion surrounding and partitioning the openings on one surface of a transparent substrate via a transparent adhesive layer. Ratio of diffused light reflectance (R _SCE ) to total light reflectance (R _SCI ) provided as an electrode and measured according to JIS Z 8722 of the surface of the aluminum pattern layer on the transparent adhesive layer side (R _SCE / R _SCI ) is 0.4 or less.

The opening of the aluminum pattern layer provided on the transparent substrate, that is, the exposed surface of the transparent adhesive layer, has a fine surface (a smooth surface with low light scattering property) facing the transparent substrate side of the aluminum thin film. The uneven shape is transferred. Therefore, the ratio (R _SCE ) of the diffused light reflectance (R _SCE ) to the total light reflectance (R _SCI ) measured according to JIS Z 8722 on the surface of the transparent adhesive layer exposed from the opening of the aluminum pattern layer. / R _SCI ) and the total light ray measured in accordance with JIS Z 8722 of the line part of the aluminum pattern layer, that is, the surface of the aluminum pattern layer in contact with the transparent adhesive layer (smooth surface with low light scattering property) It is considered that the ratio (R _SCE / R _SCI ) of the diffused light reflectance (R _SCE ) to the reflectance (R _SCI ) is equivalent.
Therefore, in the present invention, the numerical value of the light reflectance ratio (R _SCE / R _SCI ) on the surface of the transparent adhesive layer exposed from the opening of the aluminum pattern layer is the shape of the electrode film;
In the laminate of transparent substrate / transparent adhesive layer / aluminum pattern layer, light for measurement is incident from the transparent substrate side, and the surface of the aluminum pattern layer passes through the interposed transparent substrate and transparent adhesive layer. The value of (R _SCE / R _SCI ) is measured by the light reflected at, and is indirectly evaluated.

As a result of the experiments by the present inventors, the surface of the adhesive layer that is exposed to the opening where the surface of the aluminum thin film to be bonded to one surface of the transparent base material via the transparent adhesive layer is smooth is transferred. It was confirmed that the haze of the obtained electrode film can be reduced when light transmission is mainly parallel light transmission light.
Moreover, as shown in Table 1 of the examples described later, in the electrolytic copper foil, the surface on the transparent adhesive layer side can be distinguished in appearance from a rough surface and a mirror surface, but the numerical value represented by JIS B0601 arithmetic average roughness Ra is There is no difference. Here, the arithmetic average roughness Ra of JIS B0601 is extracted from the roughness curve by the reference length L in the direction of the average line, and the absolute value of the deviation from the average line of the extracted portion to the measurement curve is totaled. The average value. Moreover, although the Ra of the rough surface of the aluminum foil is larger than the Ra of the rough surface of the electrolytic copper foil, the haze value after the etching treatment is small. Further, in the aluminum foil, the mirror surface Ra is smaller than the rough surface Ra, but the root mean square roughness Rq measured in a minute range is larger in the mirror surface than in the rough surface.
From the above results, there is no correlation between the arithmetic average roughness Ra, the appearance of the metal foil surface, and the haze value transferred to the adhesive layer surface of the opening after the etching treatment. The correlation between the ten-point average roughness (prescribed in JIS B0601 (1994 edition)) that has been used as an index of specularity in the past and the haze transferred to the surface of the adhesive layer is the same. Not clear. Moreover, the average roughness showing the uneven | corrugated shape on the surface of metal foil changes with the methods to measure. From this, in the same arithmetic mean roughness Ra, the surface shape having a high unevenness frequency and a close unevenness interval has a large haze value after the etching process, while the unevenness frequency is low and the uneven interval is low. It is considered that the haze value after the etching process is small in a surface shape with a sparse and many flat portions.
That is, conventionally, the haze after the etching process has been reduced in correlation with the ten-point average roughness Rz because the conditions such as the roughness of the rough surface of the metal foil surface, the density of the protrusions, etc. It is concluded that it is not a design standard that can be widely applied in general when the manufacturing method of metal foil, the rough surface fine uneven shape of the surface, the density of protrusions, etc. vary in various ways. The
As a result of the above studies, the present inventors have found that the surface of the aluminum foil to be bonded to the transparent adhesive layer side is a mirror surface with low light scattering property, thereby reducing haze after the etching process with good correlation. I found it. Specifically, on one surface of a transparent substrate, the surface of aluminum foil bonded via a transparent adhesive layer, diffuse light reflectance to the total light reflectance was measured in accordance with JIS Z8722 (R _SCI) If the ratio of _{(R SCE) (R SCE /} R SCI) is in the range of 0.4 or less, regardless of the value of the arithmetic average roughness Ra of the surface, transmitting an opening of the aluminum pattern layer after the etching treatment The haze of light to be reduced can be reduced.
The arithmetic average roughness Ra and the ten-point average roughness Rz, which have been used as general indices representing the uneven shape of the surface of the metal foil, are the specularity of the metal foil, and further, the opening of the opening to which the surface is transferred. It was not necessarily related to the haze of the adhesive layer.

The ratio of the total light reflectance diffuse light reflectance for _{(R SCI) (R SCE)} (R SCE / R SCI) is an indicator that the surface shape of the metal foil (aluminum thin film) represents whether easily scatters light When the shape of the surface of the metal foil (aluminum thin film) is transferred to the transparent adhesive layer, it is a value that directly affects the haze of the transmitted light of the obtained electrode film.
In the present invention, the surface of the aluminum pattern layer on the transparent substrate side is a smooth surface with low light scattering properties (by selecting such a surface of the aluminum thin film). the total light reflectance of the transparent adhesive layer surface diffusion light reflectance for _{(R SCI)} the ratio of _{(R SCE) (R SCE /} R SCI) can be the above specific range, it is transparent adhesive layer surface Since the shape hardly scatters transmitted light, haze can be reduced.

Total light reflectance was measured in accordance with JIS Z8722-1982 of aluminum thin film surface of the present invention _{(R SCI)} is in compliance with JIS Z8722-1982, spectrophotometer (e.g., Konica Minolta Sensing Co., Ltd., CM-3600d) is set to the reflection mode, the light source is the standard light D65, the field of view is 2 °, the measurement diameter is 4 mmφ or more, and the detector is the total reflection that combines both diffuse reflection and specular reflection of the reflected light. The Y value (Y of tristimulus values XYZ) is measured by setting to an SCI (Special Component Include) mode in which the (integral) intensity of light is measured. The diffusion light reflectance was measured in accordance with JIS Z8722-1982 of aluminum thin film surface _{(R SCE)} is similarly using spectrophotometer, a light source, field of view, and measuring the diameter is the same as above, The detector is set to an SCE (Special Component Exclude) mode that measures the (integral) intensity of only diffusely reflected light in the reflected light, and the Y value (Y of tristimulus values XYZ) is measured. . Here, the tristimulus value XYZ is defined by JIS Z8722-1982, and is determined by illuminating a sample placed in an ideal environment with a standard light source and calculating the spectral analysis result of the reflected light from the sample. It is a value to be set.

〔Layer structure〕
The layer structure of the electrode film for touch panels according to the present invention will be described with reference to the drawings.
A sectional view of an example of an electrode film according to the present invention is conceptually shown in FIG. In the cross-sectional views shown in FIG. 1 and FIG. 2, for ease of explanation, the scale in the thickness direction (vertical direction in the figure) is greatly enlarged and exaggerated than the scale in the plane direction (left and right direction in the figure). In addition, the line width of the aluminum pattern layer is exaggerated significantly larger than the arrangement period. In the electrode film 10 shown in FIG. 1, an electrode made of an aluminum pattern layer 3 is laminated on one surface of a transparent substrate 1 with a transparent adhesive layer 2 interposed therebetween. The aluminum pattern layer 3 has a smooth surface 3a whose surface on the transparent substrate 1 side (also a surface on the transparent adhesive layer side) has a low light scattering property, and a surface opposite to the transparent substrate 1 side is non-smooth It is the surface 3b. In the present invention, it is essential that the surface of the aluminum pattern layer 3 on the transparent adhesive layer 2 side is a smooth surface 3a. Accordingly, the side surface opposite to the transparent adhesive layer 2 side of the aluminum pattern layer 3 may be the smooth surface 3a. Although not shown, the aluminum pattern layer 3 may have a blackened layer by blackening the surface (non-smooth surface 3b) opposite to the surface on the transparent substrate 1 side.
Moreover, as shown in FIG. 2, on the surface opposite to the aluminum pattern layer 3 side of the transparent substrate 1, a hard coat layer, an antireflection layer (AR layer), an antiglare layer (AG layer), etc. One or two or more optical function layers 4 may be provided.
Hereinafter, the electrode film of the present invention will be described in order from a transparent substrate.

(1) Transparent base material The transparent base material 1 used by this invention is a part layer which comprises an electrode film, and is a layer used as a base material for laminating | stacking an aluminum pattern layer through a transparent adhesive layer. . The transparent substrate may be selected according to the intended use in consideration of performance such as transparency in the visible region (light transmittance), mechanical strength, and heat resistance. Specific examples of such a transparent substrate include a sheet (or film; the same applies hereinafter) or a plate made of an organic material such as resin or an inorganic material such as glass. The higher the transparency of the transparent substrate, the better. However, the light transmittance in the visible light region of 380 to 780 nm is preferably 70% or more, more preferably 80% or more. The light transmittance can be measured using a spectrophotometer (for example, UV-3100PC manufactured by Shimadzu Corporation) and a value measured in the air at room temperature.
Further, the haze value of the transparent substrate in accordance with JIS K7105-1981 is preferably 10% or less, more preferably 2.0% or less, and particularly preferably 1.0% or less. . By setting the haze value of the transparent substrate in the above range, the haze of the electrode film of the present invention can be kept low together with the effect of the present invention.

  Examples of the resin used as the material for the transparent substrate include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, terephthalic acid-isophthalic acid-ethylene glycol copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Polyester resins such as polyester resins, polyamide resins such as nylon 6, polyolefin resins such as polypropylene, polymethylpentene and cycloolefin polymers, acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymers, Examples thereof include cellulose resins such as triacetyl cellulose, imide resins, and polycarbonate resins.

  These resins are used alone or as a plurality of types of mixed resins (including polymer alloys), and the layer structure of the transparent substrate is used as a single layer or a laminate of two or more layers. In the case of a resin film, a uniaxially stretched or biaxially stretched film is more preferable in terms of mechanical strength. Moreover, you may add additives, such as a filler, a plasticizer, and an antistatic agent, in these resins suitably as needed. Examples of the glass include soda glass, potash glass, borosilicate glass, and quartz glass. Usually, glass is used in the form of a thick plate.

The thickness of the transparent substrate may be basically selected according to the use and is not particularly limited, but is usually 12 to 5000 μm, preferably 50 to 500 μm in the case of a film, more preferably 50 to 200 μm, plate In this case, the thickness is 500 to 3000 μm. Within such a thickness range, the mechanical strength is sufficient, warping, loosening, breakage, etc. are prevented, and it is easy to supply and process in a continuous belt shape.
In the present invention, as the transparent substrate, a material made of a flexible resin film or plate is particularly preferable in terms of good manufacturing processability and reduced weight and cost. In particular, a substrate made of these resins is referred to as a transparent resin substrate.

  As a form of the transparent resin substrate, a transparent resin film is preferable to a resin plate. Among these resin films, polyester resin films such as polyethylene terephthalate and polyethylene naphthalate are preferable in terms of transparency, heat resistance, cost, and the like, and more preferably a biaxially stretched polyethylene terephthalate film.

  In addition, a transparent substrate such as a resin film has a known surface such as a corona discharge treatment, a plasma treatment, an ozone treatment, a flame treatment, a primer treatment, a pre-heat treatment, a dust removal treatment, a vapor deposition treatment, and an alkali treatment. An adhesion treatment may be performed.

(2) Aluminum pattern layer The aluminum pattern layer 3 is a pattern layer formed of an aluminum thin film, and constitutes an electrode of an electrode film for a touch panel. Although the layer itself is opaque, it is a layer in which both conductivity and light transmission required as a touch panel electrode are achieved by forming a pattern in which an unformed portion of the layer such as an opening is provided.
In the present invention, a transparent adhesive layer side surface of the aluminum pattern layer, diffuse light reflectance to the total light reflectance was measured in accordance with _{JIS Z8722 (R SCI) (R} SCE) ratio _(R SCE _/ R _SCI ) Is 0.4 or less, preferably 0.3 or less. Total light reflectance diffuse light reflectance for _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) by optimizing to have the specific reflection characteristics, the surface properties of the aluminum pattern layer Since the surface of the transparent adhesive layer at the opening of the transferred aluminum pattern layer has a shape that hardly scatters light, the haze of the electrode film can be reduced.
In addition, the said specific reflective characteristic is acquired by raising the polish degree of the rolling roll surface of the aluminum thin film which forms an aluminum pattern layer.

  The aluminum of the aluminum pattern layer may be pure aluminum alone, but it is mainly composed of aluminum, and may be aluminum alloy in addition to aluminum alone. These are collectively referred to as aluminum in the present invention, but the conductivity decreases when the purity of aluminum is low. Therefore, the purity is preferably higher in terms of high conductivity, and aluminum having a purity of 99.0% or more is preferable. Such an aluminum pattern layer using aluminum having a purity of 99.0% or more is a foil conforming to the aluminum foil defined by JIS H4160 (aluminum and aluminum alloy foil) and JIS H4170 (high purity aluminum foil). It can be formed by using

In the present invention, the degree of haze reduction on the exposed surface of the transparent adhesive layer formed by transferring and shaping the smooth surface of the aluminum thin film forming the aluminum pattern layer is, as described above, the specific light reflection of the aluminum thin film adhesive surface. It greatly depends on (correlates with) the numerical value of the rate ratio ( _RSCE / _RSCI ). He stated that the dependence (correlation) on the arithmetic average roughness Ra defined in JIS B0601 is low. However, if the value of Ra becomes too large, the surface unevenness generally increases, and therefore the haze on the exposed surface of the adhesive layer also tends to increase (weak correlation). In view of this point, it can be said that it is preferable to select a small Ra within a possible range on the assumption that a specific light reflectance ratio (R _SCE / R _SCI ) is set. Usually, Ra is set to 0.2 μm or less, more preferably 0.15 μm or less.

  What is necessary is just to select the thickness of an aluminum pattern layer suitably from points, such as electroconductivity, workability, and mechanical strength, Specifically, it is 1-100 micrometers, Preferably it is 5-20 micrometers, More preferably, it is 8-15 micrometers. If the thickness is small, the conductivity, mechanical strength, and the like are lowered. If the thickness is thick, the workability is lowered.

  The pattern shape of the aluminum pattern layer in plan view is, for example, a mesh (lattice or mesh) shape, a stripe (stripe or parallel line group) shape, a spiral (spiral or spiral), etc., which has both conductivity and light transmittance. This is a known pattern. Among them, a mesh shape and a square lattice shape are typical, and in addition, examples of the lattice shape include a rectangular lattice, a rhombus lattice, a hexagonal lattice, and a triangular lattice. The mesh has a plurality of openings having these shapes, and the openings are line portions (line portions or line portions) that define the openings. The line portions are usually line-shaped with a uniform width, and usually the openings and the spaces between the openings are all the same shape and the same size.

  The line width of the line portion of the pattern is, for example, 5 to 50 μm, preferably 5 to 30 μm, and the line interval (pitch) that is a line repetition period is, for example, 100 to 500 μm.

(3) Transparent adhesive layer If the transparent adhesive layer 2 is a layer which can adhere | attach an aluminum pattern layer and a transparent base material and has sufficient transparency, the kind etc. will not be specifically limited. However, in the present invention, since the aluminum thin film constituting the aluminum pattern layer and the transparent base material are bonded together via the transparent adhesive layer, the aluminum thin film is formed into a pattern by etching. The layer also preferably has etching resistance. Specific examples include polyurethane resins such as polyurethane ester resins and two-component curable urethane resins, acrylic resins, polyester resins, and epoxy resins. The transparent adhesive layer used in the present invention may be an ultraviolet curable type or a thermosetting type. In particular, a polyurethane resin, an acrylic resin, a polyester resin, particularly a two-component curable urethane resin is preferable from the viewpoint of adhesion to a transparent substrate.

The film thickness of the transparent adhesive layer is preferably in the range of 0.5 μm to 50 μm, and more preferably in the range of 1 μm to 20 μm. Thereby, a transparent base material and an aluminum pattern layer can be adhere | attached firmly, and it prevents that a transparent base material receives the influence of etching liquid, such as iron oxide, in the case of the etching which forms an aluminum pattern layer Because it can.
Further, the refractive index of the transparent adhesive layer is preferably in the range of 1.41 to 1.59 from the viewpoint of reducing interface reflection due to the difference in refractive index with the transparent base material. It is preferable to be within the range of 52.

[Other layers]
The electrode film of the present invention has an optical function such as an antiglare function and an antireflection function on the surface opposite to the aluminum pattern layer 3 side of the transparent substrate 1, or an anti-scratch function, an antifouling function, a water repellent function, A functional layer 4 having other functions such as an antistatic function and an antibacterial function may be provided. In particular, a functional layer having an optical function is also referred to as an optical functional layer. The functional layer may be formed as a multilayer in addition to a single layer.
<Abrasion-resistant functional layer>
The scratch-resistant (hard coat) layer preferably exhibits a hardness of “H” or higher in a pencil hardness test specified by JIS K5600-5-4 (1999). The material is not particularly limited as long as the same transparency can be realized.
The scratch-resistant layer (hard coat) layer is, for example, a polyfunctional (meth) acrylate prepolymer such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, or trimethylolpropane tri (meth) acrylate. , Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and other polyfunctional (meth) acrylate monomers such as tri- or more functional compounds, either alone or in combination of two or more of these It can be formed as a coating film using a curable resin. Typical examples of ionizing radiation include ultraviolet rays and electron beams. When ionizing radiation curable resins are used as ultraviolet curable resins, sensitization is performed as a photopolymerization initiator or a photopolymerization accelerator. An agent can be added. Here, (meth) acrylate is a composite notation meaning acrylate or methacrylate. The scratch resistance function (hard coat) can be formed by a wet film formation method such as coating on the transparent substrate by diluting the material with a solvent as necessary.

<Anti-glare layer>
The antiglare layer (Anti Glare layer, abbreviated as AG layer) is formed on the surface of the layer by forming a coating using an inorganic filler such as silica in a resin binder, or by forming using a pressing of a forming plate, etc. It can be formed as a layer provided with fine irregularities for irregularly reflecting external light. As the resin of the resin binder, a curable acrylic resin, an ionizing radiation curable resin, or the like is preferably used in the same manner as the scratch-resistant (hard coat) layer because the surface layer is desired to have surface strength.

<Antireflection layer>
The antireflection layer (Anti Reflection layer, abbreviated as AR layer) is a single layer of a low refractive index layer, or a low refractive index layer and a high refractive index layer, and the low refractive index layer is positioned in the uppermost layer. A multilayer structure in which the layers are alternately laminated is generally used, and can be formed by a dry film formation method such as vapor deposition or sputtering, or by using a wet film formation method such as coating. Note that silicon oxide, magnesium fluoride, fluorine-containing resin, or the like is used for the low refractive index layer, and titanium oxide, zinc sulfide, zirconium oxide, niobium oxide, or the like is used for the high refractive index layer. Here, the high (low) refractive index layer means that the refractive index of the layer is relatively high (low) compared to a layer adjacent to the layer (for example, a low (high) refractive index layer). Meaning.
When the antireflection layer is further provided with a scratch resistance function, the antireflection layer is appropriately formed using a material having high hardness described in the section of the scratch resistance function (hard coat) layer.

  The haze value measured based on JIS K7105-1981 of the electrode film which concerns on this invention can be 10% or less, Furthermore, it can be 5% or less, and has transparency sufficient as an electrode film.

The surface resistance value of the aluminum pattern layer of the electrode film according to the present invention is 100 to 1000 Ω / □, more preferably 300 to 500 Ω / □. When the surface resistance value is smaller than the above range, it is appropriately adjusted to be within the above range. Adjustment methods include, for example, reducing the thickness of the aluminum pattern layer, reducing the aluminum purity of the aluminum foil used in the aluminum pattern layer (alloying aluminum), thinning the aluminum pattern layer, and increasing the aperture ratio. Etc.
The surface resistance value can be measured by a 4-terminal 4-probe method using a resistivity meter / Loresta EPMCP-T360 type (manufactured by Mitsubishi Chemical Analytech).

II. Method for Producing Touch Panel Electrode Film A method for producing an electrode film for a touch panel according to the present invention comprises an aluminum pattern layer having a plurality of openings and a line portion surrounding and partitioning on one surface of a transparent substrate. A method for producing an electrode film for a touch panel comprising:
(I) An aluminum thin film having a surface having a diffused light reflectance ( _RSCE ) ratio ( _RSCE / _RSCI ) of 0.4 or less to the total light reflectance ( _RSCI ) measured according to JIS Z 8722 The process to prepare,
(Ii) A step of laminating the aluminum thin film on one surface of the transparent substrate with the surface of which R _SCE / R _SCI is 0.4 or less facing the transparent substrate via a transparent adhesive layer And (iii) a step of etching the aluminum thin film into a predetermined pattern shape to form an electrode.

According to the method for producing an electrode film of the present invention, the cost of the electrode film can be reduced by using aluminum which is cheaper than copper as the material of the metal foil used for the metal pattern layer.
Further, on one surface of a transparent substrate, through a transparent adhesive layer, a ratio of the diffuse light reflectance to the total light reflectance of the aluminum thin film _{(R SCI) (R SCE)} (R SCE / R SCI) is the By laminating a smooth surface (mirror surface) with a low light scattering property in a specific range so as to face the transparent substrate, the surface of the transparent adhesive layer in the opening after etching of the aluminum thin film is subjected to light scattering. Since it is difficult to form, an electrode film with reduced haze can be obtained.

Hereinafter, each step will be described.
(I) An aluminum thin film having a surface having a diffused light reflectance ( _RSCE ) ratio ( _RSCE / _RSCI ) of 0.4 or less to the total light reflectance ( _RSCI ) measured according to JIS Z 8722 Step to be prepared In this step, an aluminum thin film is first prepared.
The aluminum thin film used in the present invention has a surface (smooth surface with low light scattering property) having the specific reflection characteristics. As will be described later, through the step of laminating the smooth surface of the aluminum thin film so as to face one surface of the transparent substrate through the transparent adhesive layer, the opening of the aluminum thin film after the etching treatment is processed. Since the surface of the transparent adhesive layer has a shape that hardly scatters light, the resulting electrode film can be reduced in haze.
As the aluminum thin film, the one described in the section “(2) Aluminum pattern layer” can be used.

(Ii) A step of laminating the aluminum thin film on one surface of the transparent substrate with the surface of which R _SCE / R _SCI is 0.4 or less facing the transparent substrate via a transparent adhesive layer In this step, first, a transparent substrate is prepared, and one surface of the transparent substrate is coated with a transparent adhesive to form a transparent adhesive layer.
As the transparent substrate, those described in the section “(1) Transparent substrate” can be used.
In addition, as a layer forming method, a known layer forming method, for example, a coating method such as roll coating, comma coating, gravure coating, or die coating, or printing such as screen printing or gravure printing that allows easy partial formation in an arbitrary shape. The law can be adopted as appropriate.
Next, an aluminum thin film is laminated on the surface of the transparent adhesive layer of the transparent substrate with the smooth surface side having a low light scattering property facing.

(Iii) Step of etching the aluminum thin film into a predetermined pattern shape to form an electrode In this step, a resist layer is provided in a predetermined pattern on the surface of the aluminum thin film laminated on the transparent substrate. After the uncovered portion of the aluminum thin film is removed by etching (corrosion), an electrode made of an aluminum pattern layer is formed by an etching process that removes the resist layer. Among the etching processing methods, it is preferable to adopt a so-called photolithography method from the viewpoint of fine processing accuracy.

Hereinafter, the photolithography method will be described.
First, masking is performed. For example, a photosensitive resist is applied to the outermost surface on the aluminum thin film side, dried, and then closely exposed with a photomask having a predetermined pattern, developed with warm water, subjected to a hardening process, and baked. A resist layer of the pattern is formed. Note that either a negative type or a positive type of photosensitive resist can be used. When the photosensitive resist is a negative type, a photomask pattern having a transparent line portion is used. When the photosensitive resist is a positive type, a photomask pattern having a transparent opening is used. Further, the exposure pattern is a desired pattern as an electrode film. When a mesh shape is adopted as the pattern, the exposure pattern is composed of a pattern of at least a mesh region.

  In the winding process, the photosensitive resist is applied by dipping (dipping), curtain coating, or hanging a resist made of casein, PVA, gelatin or the like onto the aluminum thin film surface while the belt-like laminate is conveyed continuously or intermittently. Use a sink or other method. Also, the resist may be a dry film resist instead of coating, and workability can be improved.

  Etching is performed after masking. As the etching solution used for the etching, an aqueous solution of ferric chloride or cupric chloride that can be easily circulated is preferable in the present invention in which etching is continuously performed. The etching is basically the same as the equipment and process for manufacturing a shadow mask for a color TV cathode ray tube that etches a strip-like continuous steel material, particularly a thin plate having a thickness of 20 to 80 μm. Single-wafer processing in the case of using glass as a transparent substrate has been performed for a long time. After etching, the substrate may be dried after washing with water, stripping the resist with an alkaline solution, and washing.

  Thus, the haze value measured based on JISK7105: 1981 of the obtained electrode film can be 10% or less, and can also be 5% or less.

II. Touch panel The touch panel according to the present invention is a touch panel in which two electrode films having transparent conductive electrodes on one surface of a transparent substrate are arranged with electrodes facing each other via a spacer,
Of the two electrode films, at least one of the electrode films is the electrode film for a touch panel according to the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the touch panel which can reduce a haze can be provided at low cost by using the electrode film which concerns on this invention mentioned above for the at least one electrode film of a touch panel.

In the touch panels 50A and 50B according to the present invention, as shown in FIG. 3 and FIG. 4 as an example, two electrode films are arranged with the electrodes facing each other at a constant interval G with a spacer 6 interposed therebetween. At least one of the two electrode films is composed of the electrode film having the structure of the present invention. In particular, in the embodiment of FIG. 3, the two electrode films are both made of the electrode film of the present invention. The electrode film on the display device 60 side has an aluminum pattern layer 3 laminated as an electrode on one surface of the transparent substrate 1 with a transparent adhesive layer 2 interposed therebetween. The surface on one side (also the surface on the transparent adhesive layer side) is a smooth surface 3a having a low light scattering property, and the surface opposite to the transparent substrate 1 side is the non-smooth surface 3b. Yes. In addition to the electrode film on the input side with which the input pen 7 is in contact, the optical functional layer 4 is further laminated on the surface of the transparent substrate 1 opposite to the aluminum pattern layer 3 side. The electrode film 20 is formed.
The touch panel 50B shown in FIG. 4 includes the electrode film 20 of the present invention including the optical functional layer 4 on the input-side electrode film, and the conventional electrode film on the display device 60-side electrode film. An electrode film 30 in which a transparent conductive film 40 such as ITO is formed on the entire surface of the transparent substrate 1 is used, and the others are configured similarly to FIG.

In addition, in order to improve the contrast of the display (image, number, etc.) of the display device viewed through the touch panel in the presence of external light such as sunlight, the input side electrode film 10 (observer side electrode film) A blackened layer may be provided on the surface (smooth surface 3a) of the aluminum pattern layer 3 on the transparent substrate 1 side.
As the blackening layer, a known layer may be appropriately employed. For example, as the blackening layer, an inorganic material such as a metal, an organic material such as a black resin, or the like can be used. The inorganic material is, for example, a metal compound such as a metal or an alloy, a metal oxide, or a metal sulfide, and can be formed by a known blackening process such as a plating method. Moreover, as black resin, it can form as a layer which contained black coloring agents, such as carbon black, in resin.

  The touchscreen electrode films 10 and 20 and the touchscreens 50A and 50B according to the present invention include a display surface of a small game machine, a display surface of a computer display, a display surface of a TV display, a display surface of electronic paper, etc. It can be preferably used as a display surface, various electronic guide boards, a display surface of a database, a touch panel mounted on a display surface of a ticket vending machine, or a component thereof. Such a display device may be a liquid crystal display device (LCD), a plasma display device (PDP), an electroluminescence (EL) display device, a cathode ray tube (CRT) display device, an electrophoretic display device, or the like. Good.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be described more specifically with reference to examples. These descriptions do not limit the present invention.

Hereinafter, as examples and comparative examples of the present invention;
An electrode film comprising a laminate of transparent substrate / transparent adhesive layer / aluminum pattern layer was prepared. In this embodiment, measurement light is incident from the transparent base material side, and the surface of the aluminum pattern layer on the transparent adhesive layer side has a specific light reflectance ratio (R _SCE / R _SCI ) (“aluminum pattern”). The layer was also referred to as “ _RSCE / _RSCI ”), and the haze value of the transmitted light from the electrode film was measured to evaluate the relationship between the two.
Also, In addition, for the aluminum thin film per se separately the unpatterned directly anything without intervening light ray reflectance ratio of the adhesive surface (surface contacting the transparent adhesive layer side) between (R _SCE / R _SCI ) (also referred to as “R _SCE / R _SCI of the aluminum thin film itself. It is also a physical characteristic value specific to the surface of the aluminum thin film)” was also measured.
And the correlation between the numerical value of both ( _RSCE / _RSCI ) was evaluated.
Prior to this, as reference data, various surface roughness values (Ra, Rq, and Rz), the light reflectance ratio ( _RSCE / _RSCI ), and the obtained configuration described above were separately provided as reference data. In order to confirm the correlation with the haze value of the electrode film, for various metal thin films, ( _RSCE / _RSCI ) of the metal thin film itself was measured, and Ra, Rq, and Rz based on JIS standards (below) Each surface roughness value of was measured.
Furthermore, in order to confirm how the haze value of the exposed surface of the transparent adhesive, to which the surface shape of the metal thin film is transferred and shaped, depends on the value of the light reflectance ratio ( _RSCE / _RSCI ), The haze of the electrode film itself having the above-described configuration using each metal thin film was measured.
Together, these are presented below as Reference Test 1 to Reference Test 4 (the obtained samples are Reference Example 1 to Reference Example 4).

[Reference test (and reference example)]
(Reference test 1)
First, as a metal foil to be a metal thin film, an electrolytic copper foil (B2X-WS: trade name, manufactured by Furukawa Circuit Foil) with a thickness of 12 μm was prepared. Electric Kaidohaku has a mirror and rough surface, measured in the rough surface of the electric Kaidohaku, the ratio _(R SCE _/ R _SCI) of total light reflectance diffuse light reflectance for _{(R SCI) (R SCE)} As a result, the ratio (R _SCE / R _SCI ) of the rough surface of the electrolytic copper foil itself was 1.0.
In addition, the surface roughness values of Ra, Rq, and Rz specified in JIS standards were measured for the rough surface of the metal thin film.
In addition, as a transparent substrate, a non-colored transparent biaxially stretched polyethylene terephthalate (PET) film (A4300: trade name, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and having a polyester resin primer layer formed on one side is formed. Prepared.
Next, on the surface of the PET film on which the primer layer is formed, a transparent adhesive (12 parts by mass of a polyester polyurethane polyol having an average molecular weight of 30,000 as a main component and a curable agent is used to make the dry thickness 7 μm. A two-component curable urethane resin adhesive composed of 1 part by mass of a diisocyanate prepolymer was coated to form a transparent adhesive layer.

  Next, on the primer layer on one side of the PET film, dry lamination is performed with the rough surface side of the electrolytic copper foil facing the PET film side (transparent adhesive layer side) through the transparent adhesive layer. As a result, a continuous strip-shaped laminate was obtained. After dry laminating, the adhesive was cured by curing at 50 ° C. for 3 days.

Next, a copper mesh layer as a metal pattern layer including an opening portion and a line portion was formed on the above-described continuous strip-shaped laminate by etching the electrolytic copper foil using a photolithography method.
Specifically, the etching is performed by applying a photosensitive negative etching resist to the entire exposed surface (in this case, the mirror surface) of the electrolytic copper foil of the laminate, and then exposing and developing a mask having a desired mesh pattern. Then, after hardening and baking, after processing the resist layer into a pattern in which the resist layer remains on the area corresponding to the line portion of the mesh and there is no resist layer on the area corresponding to the opening, The electrolytic copper foil in the resist layer non-formation region was removed by etching with a ferric chloride aqueous solution to form a mesh-shaped opening, and then washing with water, stripping of the resist, washing and drying were sequentially performed.

  The mesh shape of the mesh-like region was such that the opening portion was square, the line width of the linear portion serving as the non-opening portion was 20 μm, the line interval was 300 μm, and the height of the line portion was 12 μm. In this way, an electrode film sheet having a width dimension of 605 mm was obtained.

(Reference test 2)
In Reference Test 1, an electrode film sheet was obtained in the same manner as in Reference Test 1 except that the surface of the electrolytic copper foil to be laminated on the transparent substrate was a mirror surface.
Incidentally, in the mirror surface of the electrolytic copper foil, the ratio was measured _(R SCE _/ R _SCI), electric Kaidohaku mirror itself ratio of diffuse light reflectance to the total light reflectance _{(R SCI) (R SCE)} ( R _SCE / R _SCI ) was 0.9.

(Reference test 3)
In Reference Test 1, a rolled aluminum foil (1N30-B1: trade name, manufactured by Sumi Light Aluminum Foil Co., Ltd.) having a thickness of 12 μm was used as a metal foil to form a metal thin film, and was not in contact with the rolling roller of the aluminum foil. The electrode film sheet was obtained in the same manner as in Reference Test 1 except that the surface (non-smooth surface) on the side was directed to the transparent substrate side and laminated on the transparent substrate via a transparent adhesive layer. It was.
Note that the non-smooth surface of the aluminum foil, the total light reflectance diffuse light reflectance for _{(R SCI)} was measured the ratio of _{(R SCE) (R SCE /} R SCI), of the aluminum foil non-smooth surface itself The ratio (R _SCE / R _SCI ) was 0.8.

(Reference test 4)
In Reference Test 3, an electrode film sheet was obtained in the same manner as in Reference Test 3 except that the surface of the aluminum foil to be laminated was smoothed on the transparent substrate via a transparent adhesive layer.
Note that the smooth surface of the aluminum foil, was measured the ratio _(R SCE _/ R _SCI) of total light reflectance diffuse light reflectance for _{(R SCI) (R SCE)} , the ratio of the aluminum foil smooth surface itself ( R _SCE / R _SCI ) was 0.3.

The following points were evaluated for each of the above reference tests. The results are listed in Table 1.
(1) Ratio of metal foil surface itself ( _RSCE / _RSCI )
About the metal foil of the state before lamination | stacking on a transparent base material, this metal foil which measured the surface planned to adhere | attach on the transparent base material side based on JISZ8722-1982 without interposing any layer in between. The total light reflectance (%) of the (thin film) itself is set to a reflection mode with a spectrocolorimeter (Konica Minolta Sensing Co., Ltd., CM-3600d), the light source is standard light D65, field of view 2 °, measurement diameter The detector is set to 8 mmφ, and the detector is set to a SCI (Special Component Included) mode in which the (integrated) intensity of total reflected light combining both diffuse reflected light and specular reflected light is measured. (Y of tristimulus value XYZ) was measured. In addition, the diffused light reflectance (%) according to JIS Z8722-1982 of the surface of the metal foil on the transparent substrate side is similarly determined using the spectrocolorimeter, and the light source, field of view, and measurement diameter are the same as described above. The specular reflection light is absorbed and cut off by an optical trap, so that the detector is set to an SCE (Special Component Excluded) mode in which the (integral) intensity of only the diffuse reflection light out of the reflection light is set, and the Y value (3 Stimulus values XYZ Y) were measured.
(2) Arithmetic average roughness Ra of the metal foil surface
The center line average roughness Ra of the fine irregularities on the metal foil surface was measured with a stylus type surface roughness meter according to JIS B0601 (1982 version).
(3) root mean square roughness Rq of metal foil surface
The root mean square roughness Rq of the metal foil surface was measured with a stylus type surface roughness meter as an average value obtained by squaring the measurement curve (crest itself) of fine irregularities on the metal foil surface.
(4) Ten-point average roughness of metal foil surface RzJIS
As for the micro unevenness of the metal foil surface, when a roughness curve is adopted as the contour curve of the micro unevenness, the ten-point average roughness RzJIS of the contour curve is determined according to JIS B0601 (1994 edition). Measured with a meter.
In addition, since the measurement of Rz in the said reference test was aimed at reconfirmation of the presence or absence of correlation with Rz and the haze after an etching, it stopped only the measurement of the reference example 1 and the reference example 2. FIG.
(5) Haze value The haze value of the electrode film after the etching treatment was measured according to JIS K 7105-1981 “Testing method for optical properties of plastic”.

[Examples and Comparative Examples]
Example 1
First, as an aluminum thin film, a rolled aluminum foil having a thickness of 12 μm and a continuous belt shape (1N30-B1: trade name, manufactured by Sumi Light Aluminum Foil Co., Ltd.) was prepared. The aluminum foil has a smooth surface and a non-smooth surface. The aluminum foil in the state before lamination on the transparent substrate 1 (unpatterned) is diffused with respect to the total light reflectance ( _RSCI ) without any layer between them on the smooth surface to be bonded. When the ratio of light reflectance ( _RSCE ) ( _RSCE / _RSCI ) was measured, the ratio of the aluminum thin film itself ( _RSCE / _RSCI ) was 0.3.

Moreover, as the transparent base material 1, a polyester resin-based primer layer is formed on one side, and a continuous belt-like uncolored transparent biaxially stretched polyethylene terephthalate (PET) film having a thickness of 100 μm (A4300: trade name, manufactured by Toyobo Co., Ltd.) Prepared.
Next, on the surface of the PET film on which the primer layer is formed, a transparent adhesive (12 parts by mass of a polyester polyurethane polyol having an average molecular weight of 30,000 as a main component and a curable agent is used to make the dry thickness 7 μm. A transparent adhesive layer 2 was formed by coating a two-component curable urethane resin adhesive comprising 1 part by mass of a diisocyanate prepolymer.

  Next, on the primer layer on one side of the PET film, the laminate layer is laminated by dry lamination so that the smooth surface side of the aluminum foil faces the PET film side via the transparent adhesive layer. Obtained. After dry laminating, the adhesive was cured by curing at 50 ° C. for 3 days.

Next, an aluminum pattern layer 3 as an electrode including an opening and a line portion was formed on the above-described continuous strip-shaped laminate by etching the aluminum foil using a photolithography method.
Specifically, the above-mentioned etching is performed by applying a photosensitive negative etching resist to the entire exposed surface of the aluminum foil of the laminate, then exposing the mask with a desired mesh pattern, developing, hardening, and baking. Then, after processing the resist layer into a pattern in which the resist layer remains on the area corresponding to the line portion of the mesh and there is no resist layer on the area corresponding to the opening, The aluminum foil in the resist layer non-formation region was removed by etching to form a mesh-shaped opening, and then water washing, resist peeling, washing, and drying were sequentially performed.

  The mesh shape of the mesh-like region was such that the opening portion was square, the line width of the linear portion serving as the non-opening portion was 20 μm, the line interval was 300 μm, and the height of the line portion was 12 μm. In this way, an electrode film sheet 10 having a width dimension of 605 mm was obtained.

Next, the electrode film sheet 10 obtained above was cut into a square shape having a length of 50 mm and a width of 50 mm to obtain a test piece. In the test piece, measurement light is incident from the transparent substrate side, and the total light reflectance (R) of the surface (smooth surface) of the aluminum pattern layer on the transparent substrate side through the transparent substrate and the transparent adhesive layer. diffuse light reflectance against _{SCI) (ratio} of _{R SCE) (R SCE / R} SCI) was determined. The ratio ( _RSCE / _RSCI ) of the aluminum pattern layer was 0.34.
In addition, the total light reflectance (%) measured based on JIS Z8722-1982 of the smooth surface of the aluminum pattern layer is set to a spectrocolorimeter (Konica Minolta Sensing Co., Ltd., CM-3600d) in the reflection mode. The light source is the standard light D65, the field of view is 2 °, and the measurement diameter is 8 mmφ, and the detector measures the (integrated) intensity of the total reflected light that combines both diffuse reflected light and specular reflected light. In such SCI mode, the Y value was measured. In addition, the diffused light reflectance (%) of the smooth surface according to JIS Z8722-1982 is similarly measured using a spectrocolorimeter, with the light source, field of view, and measurement diameter being the same as described above, and the specular reflected light is optically trapped. Then, the detector was set to the SCE mode in which the detector measures the (integrated) intensity of only the diffusely reflected light out of the reflected light, and the Y value was measured.

(Comparative Example 1)
In Example 1, an electrode film sheet was obtained in the same manner as in Example 1 except that the surface of the aluminum foil to be laminated was set to the non-smooth surface side through the transparent adhesive layer on the transparent substrate. It was. Incidentally, in the non-smooth surface of the aluminum foil, the ratio of the pre-laminated on a transparent substrate state total light reflectance (unpatterned) _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R _SCI ) was measured without any layer in between, and the ratio of the aluminum thin film (R _SCE / R _SCI ) was 0.8.
Next, the electrode film sheet obtained above was cut into a square shape having a length of 50 mm and a width of 50 mm to obtain a test piece. In the test piece, measurement light is incident from the transparent substrate side, and the total light reflectance of the surface (non-smooth surface) of the aluminum pattern layer on the transparent substrate side through the transparent substrate and the transparent adhesive layer ( diffuse light reflectance for R _{SCI) (ratio} of _{R SCE) (R SCE / R} SCI) was determined. The ratio of the aluminum pattern layer (R _SCE / R _SCI ) was 0.72.

(Evaluation results)
The haze values of the electrode films obtained in the above examples and comparative examples were measured according to JIS K 7105-1981 “Testing methods for optical properties of plastics”. The results are listed in Table 2.

(Summary of results)
From Table 2, in the obtained electrode film, the diffusion with respect to the total light reflectance ( _RSCI ) of the surface of the aluminum pattern layer on the transparent substrate side through the transparent substrate and the transparent adhesive layer from the transparent substrate side As a result of measuring the ratio of light reflectance ( _RSCE ) ( _RSCE / _RSCI ), in Example 1 in which the ratio of aluminum pattern layer ( _RSCE / _RSCI ) is 0.4 or less, the haze value is 6 A low haze (low haze) of 0.0% or less was obtained. On the other hand, in Comparative Example 1 in which the ratio ( _RSCE / _RSCI ) of the aluminum pattern layer was more than 0.4, the haze value was 36.5%, which was high haze (high haze).
Further, from Table 2, the ratio ( _RSCE / _RSCI ) of the aluminum thin film itself before laminating on the transparent substrate on the side of the transparent substrate (the surface on the laminating side) and the aluminum pattern layer corresponding to the aluminum thin film The ratio of the surface on the transparent substrate side ( _RSCE / _RSCI ) is comparable, and a correlation is found between the ratio ( _RSCE / _RSCI ) and the haze value.
Further, in Reference Example 1 and Reference Example 2, the haze value is increased in spite of the fact that the centerline average roughness Ra is smaller than that in Reference Example 3. Further, in Reference Example 1, although the ten-point average roughness RzJIS is smaller than that in Reference Example 2, the haze value is increased. Further, in Reference Example 3, the haze value is significantly increased in spite of the smaller root mean square roughness Rq than in Reference Example 4. In Reference Examples 1 to 4, there is consistently a correlation between ( _RSCE / _RSCI ) and the haze value.
Therefore, it is difficult to reliably reduce the haze of the electrode film even if the ten-point average roughness RzJIS, the root mean square roughness Rq, and the centerline average roughness Ra of the surface on which the metal foil is laminated are specified. is there. In contrast, through the transparent substrate and the transparent adhesive layer from the transparent substrate side, diffuse light reflectance to the total light reflectance of the surface of the transparent substrate side of the aluminum pattern layer (R _SCI) (R _SCE ) Ratio (R _SCE / R _SCI ) is set to 0.4 or less, it is possible to reliably reduce the haze of the electrode film.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Transparent adhesive 3 Aluminum pattern layer (electrode)
3a Smooth surface 3b Non-smooth surface 4 Optical functional layer 6 Spacer 7 Input pen 10, 20, 30 Electrode film 40 Transparent conductive film 50A, 50B Touch panel 60 Display device G Distance between two electrode films

Claims (3)

An electrode composed of an aluminum pattern layer having a plurality of openings and line portions surrounding and partitioning the openings is provided on one surface of the transparent substrate via a transparent adhesive layer, and the aluminum pattern layer the ratio of the total light reflectance was measured in conformity with JIS Z 8722 of the transparent adhesive layer side surface _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R SCI) is 0.4 or less, Electrode film for touch panel. A method for producing an electrode film for a touch panel comprising an electrode comprising an aluminum pattern layer having a plurality of openings and line portions surrounding and partitioning the openings on one surface of the transparent substrate,
(I) An aluminum thin film having a surface having a diffused light reflectance ( _RSCE ) ratio ( _RSCE / _RSCI ) of 0.4 or less to the total light reflectance ( _RSCI ) measured according to JIS Z 8722 The process to prepare,
(Ii) A step of laminating the aluminum thin film on one surface of the transparent substrate with the surface of which R _SCE / R _SCI is 0.4 or less facing the transparent substrate via a transparent adhesive layer And (iii) A method for producing an electrode film for a touch panel, comprising a step of etching the aluminum thin film into a predetermined pattern shape to form an electrode. Two electrode films having transparent conductive electrodes on one surface of a transparent substrate are touch panels arranged with electrodes facing each other via a spacer,
The touch panel according to claim 1, wherein at least one of the two electrode films is the electrode film for a touch panel according to claim 1.

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