JP2016087963A - Transparent conductive body and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive body capable of easily removing a metal oxide layer and a metal layer by etching.SOLUTION: There is provided a transparent conductive body 100 containing a transparent resin substrate 10 a first metal oxide layer 12, a metal layer containing a silver alloy 16 and a second metal oxide layer 14 laminated in this order, the second metal oxide layer 14 contains ZnO as a main component and GaOand GeOas accessory components.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a transparent conductor and a touch panel using the same.

The transparent conductor is used as a transparent electrode for a display such as a liquid crystal display (LCD), a plasma display panel (PDP), and an electroluminescence panel (organic EL, inorganic EL), and a solar cell. In addition to these, they are also used for electromagnetic wave shielding films and infrared ray prevention films. As a material for the metal oxide layer in the transparent conductor, ITO in which tin (Sn) is added to indium oxide (In ₂ O ₃ ) is widely used.

  In recent years, terminals equipped with a touch panel such as smartphones and tablet terminals are rapidly spreading. These have the structure which provided the touch sensor part on the liquid crystal panel, and provided the cover glass on the outermost surface. The touch sensor unit is configured by bonding one or two glass films or a film base material on which one or both surfaces of an ITO film are formed by sputtering.

  With the increase in the size of touch panels and the high accuracy of touch sensor functions, there is a demand for transparent conductors having high transmittance and low resistance. In order to reduce the resistance of the transparent conductor using the ITO film, it is necessary to increase the thickness of the ITO film or to crystallize the ITO film by thermal annealing. However, when the ITO film is thickened, the transmittance is lowered. Also, it is usually difficult to thermally anneal the film substrate at a high temperature. For this reason, in the case of the ITO film | membrane provided on the film base material, it was in the difficult situation to make resistance low, maintaining a high transmittance | permeability.

  Under such circumstances, a transparent conductive film having a laminated structure of a metal oxide layer mainly composed of zinc oxide and a metal layer has been proposed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-291355

  In applications such as a touch panel, a transparent conductive film is patterned into a conductive portion and an insulating portion to detect a touched position. For this reason, in the transparent conductor which has a laminated structure of a metal oxide layer and a metal layer, it is calculated | required that a metal oxide layer and a metal layer can be removed collectively by an etching. However, in the laminated structure of the metal oxide layer mainly composed of zinc oxide and the metal layer, it is difficult to remove the metal oxide layer and the metal layer all together by etching.

  Therefore, in the present disclosure, in a transparent conductor having a laminated structure of a metal oxide layer containing zinc oxide as a main component and a metal layer, the metal oxide layer and the metal layer can be easily removed by etching. A transparent conductor is provided. In addition, the present disclosure provides a touch panel that can be easily manufactured by using such a transparent conductor.

In one aspect of the present invention, a transparent resin base material, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer are laminated in this order, and the second metal The oxide layer provides a transparent conductor containing ZnO as a main component and Ga ₂ O ₃ and GeO ₂ as subcomponents.

Such a transparent conductor is composed of a second metal oxide layer containing ZnO as a main component and containing Ga ₂ O ₃ and GeO ₂ as subcomponents, and a metal layer containing a silver alloy. And a laminated structure comprising: The second metal oxide layer and the metal layer are easily removed at once by etching. Moreover, it can be set as the transparent conductor which has high transparency, high electroconductivity, and the outstanding corrosion resistance. Therefore, it can be suitably used for applications that require etching, such as touch panels.

In some embodiments, the content of ZnO in the second metal oxide layer may be 70 to 90 mol% based on the total of the three components of ZnO, Ga ₂ O _3, and GeO ₂ . The content of Ga ₂ O ₃ with respect to the total of the three components may be 5 to 15 mol%. The content of GeO ₂ with respect to the total of the three components may be 5 to 20 mol%. By containing ZnO, Ga ₂ O ₃ and GeO ₂ at the above-mentioned ratio, the transparency, conductivity, corrosion resistance and etching property of the second metal oxide layer can be sufficiently increased.

In some embodiments, the first metal oxide layer may contain ZnO as a main component and Ga ₂ O ₃ and GeO ₂ as subcomponents. As a result, the first metal oxide layer, the second metal oxide layer, and the metal layer can be easily removed collectively by etching. Moreover, it can be set as the transparent conductor which has high transparency, high electroconductivity, and the outstanding corrosion resistance.

  In some embodiments, the thickness of the metal layer may be 4-11 nm. The surface resistance can be lowered while sufficiently increasing the transparency of the transparent conductor. In some embodiments, the silver alloy may be an alloy of Ag and at least one metal selected from the group consisting of Pd, Cu, Nd, In, Sn, and Sb.

  In another aspect, the present invention provides a touch panel having a sensor film on a panel plate, wherein the sensor film is composed of the above-described transparent conductor. Such a touch panel can be easily manufactured because it has a sensor film composed of the above-described transparent conductor.

  According to the present disclosure, in a transparent conductor having a laminated structure of a metal oxide layer containing zinc oxide as a main component and a metal layer, the metal oxide layer and the metal layer can be easily removed by etching. A transparent conductor can be provided. Moreover, in this indication, the touch panel which can be manufactured easily can be provided by using such a transparent conductor.

FIG. 1 is a cross-sectional view schematically showing one embodiment of a transparent conductor. FIG. 2 is a cross-sectional view schematically showing another embodiment of the transparent conductor. FIG. 3 is a schematic cross-sectional view showing an enlarged part of a cross section in one embodiment of the touch panel. 4 (A) and 4 (B) are plan views of a sensor film constituting one embodiment of the touch panel.

  Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted in some cases.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a transparent conductor. The transparent conductor 100 has a laminated structure in which a film-like transparent resin base material 10, a first metal oxide layer 12, a metal layer 16, and a second metal oxide layer 14 are arranged in this order. .

  “Transparent” in the present specification means that visible light is transmitted, and the light may be scattered to some extent. Regarding the degree of light scattering, the required level varies depending on the use of the transparent conductor 100. What has light scattering generally referred to as translucent is also included in the concept of “transparency” in this specification. The degree of light scattering is preferably small, and the transparency is preferably high. The total light transmittance of the entire transparent conductor 100 is, for example, 80% or more, preferably 83% or more, and more preferably 85% or more. This total light transmittance is a transmittance including diffuse transmitted light obtained using an integrating sphere, and is measured using a commercially available haze meter.

  It does not specifically limit as the transparent resin base material 10, The organic resin film which has flexibility may be sufficient. The organic resin film may be an organic resin sheet. Examples of organic resin films include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polycarbonate films, acrylic films, norbornene films, polyarylate films, and polyether sulfone films. , A diacetyl cellulose film, a triacetyl cellulose film, and the like. Of these, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferable.

  The transparent resin base material 10 is preferably thicker from the viewpoint of rigidity. On the other hand, the transparent resin substrate 10 is preferably thin from the viewpoint of thinning the transparent conductor 100. From such a viewpoint, the thickness of the transparent resin substrate 10 is, for example, 10 to 200 μm. The refractive index of the transparent resin substrate is, for example, 1.50 to 1.70 from the viewpoint of a transparent conductor excellent in optical characteristics. The refractive index in this specification is a value measured under the conditions of λ = 633 nm and a temperature of 20 ° C.

The transparent resin substrate 10 preferably has high dimensional stability during heating. In general, a flexible organic resin film undergoes dimensional changes due to expansion or contraction due to heating in the film production process. In uniaxial stretching or biaxial stretching, the transparent resin substrate 10 having a small thickness can be produced at low cost. When the transparent electrode 100 is heated when forming the extraction electrode, a dimensional change occurs due to thermal contraction. Such a dimensional change can be measured according to ASTM D1204-02 or JIS-C-2151. The dimensional change rate before and after the heat treatment can be obtained by the following equation, where Lo is the dimension before heating and L is the dimension after heating.
Dimensional change rate (%) = 100 × (L-Lo) / Lo

  When the rate of dimensional change (%) is positive, it indicates that it has expanded by heat treatment, and when it is negative, it indicates that it has shrunk by heat treatment. The dimensional change rate of the biaxially stretched transparent resin substrate 10 can be measured in both the traveling direction (MD direction) and the lateral direction (TD direction) during stretching. The dimensional change rate of the transparent resin substrate 10 is, for example, −1.0 to −0.3% in the MD direction and −0.1 to + 0.1% in the TD direction.

  The transparent resin substrate 10 may be subjected to at least one surface treatment selected from the group consisting of corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, and ozone treatment. Good. The transparent resin substrate may be a resin film. By using a resin film, the transparent conductor 100 can be made excellent in flexibility. Thereby, it can be used not only for transparent conductors for touch panel applications, but also for transparent electrodes such as flexible organic EL lighting, or as an electromagnetic wave shield.

  For example, when the transparent conductor 100 is used as a sensor film constituting a touch panel, the transparent resin substrate 10 is made of a flexible organic resin film so that it can be appropriately deformed with respect to external inputs such as fingers and pens. It may be used.

The second metal oxide layer 14 is a transparent layer containing an oxide, contains ZnO as a main component, and contains Ga ₂ O ₃ and GeO ₂ as subcomponents. The main component here is a component having the highest content on a molar basis in the three components of ZnO, Ga ₂ O ₃ and GeO ₂ . A subcomponent is a component which is not a main component among said three components. Since the 2nd metal oxide layer 14 contains ZnO as a main component, it is excellent in economical efficiency. Further, the second metal oxide layer 14 having both high conductivity and high transparency can be formed without using ITO. Therefore, the second metal oxide layer 14 having a low surface resistance can be obtained without performing thermal annealing.

  In the second metal oxide layer 14, the content of ZnO with respect to the total of the three components is, for example, 70 mol% or more, preferably 75 mol% or more from the viewpoint of sufficiently increasing the transmittance and conductivity. . In the second metal oxide layer 14, the content of ZnO with respect to the total of the three components is, for example, 90 mol% or less, and preferably 84 mol% or less, from the viewpoint of sufficiently increasing the storage stability. When the content of ZnO is too large, white turbidity tends to occur when stored in a high temperature and high humidity environment. On the other hand, if the content of ZnO is too small, the transmittance and conductivity tend to decrease.

In the second metal oxide layer 14, the content of Ga ₂ O ₃ relative to the total of the three components is, for example, 15 mol% or less from the viewpoint of sufficiently increasing the transmittance while sufficiently reducing the surface resistance. Preferably it is 11 mol% or less. In the second metal oxide layer 14, the content of Ga ₂ O ₃ with respect to the total of the above three components is, for example, 5 mol% or more, preferably 8 mol% or more, from the viewpoint of sufficiently increasing the storage stability. . When content of Ga ₂ O ₃ is too large, a tendency that the surface resistance increases, and the transmittance tends to decrease. On the other hand, if the Ga ₂ O ₃ content is too small, white turbidity tends to occur and surface resistance tends to increase when stored in a high temperature and high humidity environment.

In the second metal oxide layer 14, the content of GeO ₂ with respect to the total of the above three components is, for example, 20 mol% or less from the viewpoint of sufficiently increasing the transmittance while sufficiently reducing the surface resistance, preferably It is 14 mol% or less. In the second metal oxide layer 14, the content of GeO ₂ with respect to the total of the three components is, for example, 5 mol% or more, preferably 8 mol% or more, from the viewpoint of sufficiently increasing the storage stability. When the content of GeO ₂ is too large, a tendency that the surface resistance increases, and the transmittance tends to decrease. On the other hand, if the content of GeO ₂ is too small, the surface resistance tends to increase when stored in a high temperature and high humidity environment.

  The second metal oxide layer 14 has functions such as adjustment of optical characteristics, protection of the metal layer 16, and securing of conductivity. The second metal oxide layer 14 may contain a trace component or an unavoidable component in addition to the three components as long as the function is not significantly impaired. However, from the viewpoint of making the transparent conductor 100 having sufficiently high characteristics, it is preferable that the total ratio of the three components in the second metal oxide layer 14 is higher. The ratio is 95 mol% or more, for example, Preferably it is 97 mol% or more. Moreover, it is preferable that the 2nd metal oxide layer 14 does not contain ITO.

  The first metal oxide layer 12 and the second metal oxide layer 14 may be the same or different in terms of thickness, structure, and composition. The description relating to the composition of the second metal oxide layer 14 can be applied to the first metal oxide layer 12 as it is. Since the first metal oxide layer 12 has the same composition as the second metal oxide layer 14, the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are formed. It can be removed all at once by etching. Further, transparency and corrosion resistance can be further increased.

  The first metal oxide layer 12 may have a composition different from that of the second metal oxide layer 14. In this case, only the second metal oxide layer 14 and the metal layer 16 can be removed by etching, and the first metal oxide layer 12 can be left as it is.

  The thicknesses of the first metal oxide layer 12 and the second metal oxide layer 14 are, for example, 10 to 70 nm from the viewpoint of making the thickness suitable for various touch panels.

  The first metal oxide layer 12 and the second metal oxide layer 14 can be manufactured by a vacuum film formation method such as a vacuum evaporation method, a sputtering method, an ion plating method, or a CVD method. Among these, the sputtering method is preferable in that the film forming chamber can be downsized and the film forming speed is high. Examples of the sputtering method include DC magnetron sputtering. As a target, an oxide target, a metal, or a metalloid target can be used.

A wiring electrode or the like may be provided on the second metal oxide layer 14. A current that conducts through a metal layer 16 to be described later is guided from a wiring electrode or the like provided on the second metal oxide layer 14 via the second metal oxide layer 14. For this reason, it is preferable that the 2nd metal oxide layer 14 has high electroconductivity. From such a viewpoint, the surface resistance value of the second metal oxide layer 14 single film is preferably 1.0 × 10 ⁺⁷ Ω / □ (= 1.0E + 7 Ω / sq.) Or less, for example. More preferably, it is 0.0 × 10 ⁺⁶ Ω / □ or less.

  The metal layer 16 is a layer containing a silver alloy as a main component. Since the metal layer 16 has high conductivity, the surface resistance of the transparent conductor 100 can be sufficiently reduced. Examples of the metal element constituting the silver alloy include Ag and at least one selected from Pd, Cu, Nd, In, Sn, and Sb. Examples of silver alloys include Ag-Pd, Ag-Cu, Ag-Pd-Cu, Ag-Nd-Cu, Ag-In-Sn, and Ag-Sn-Sb.

  The metal layer 16 may contain an additive in addition to the silver alloy. The additive is preferably one that can be easily removed by an etching solution. The content of the silver alloy in the metal layer 16 may be, for example, 90% by mass or more, or 95% by mass or more. The thickness of the metal layer 16 is, for example, 1 to 30 nm. From the viewpoint of sufficiently increasing the total light transmittance while sufficiently reducing the surface resistance of the transparent conductor 100, the thickness of the metal layer 16 is preferably 4 to 11 nm. If the thickness of the metal layer 16 is too large, the total light transmittance tends to decrease. On the other hand, if the thickness of the metal layer 16 is too small, the surface resistance tends to increase.

  The metal layer 16 has a function of adjusting the total light transmittance and surface resistance of the transparent conductor 100. The metal layer 16 can be produced by a vacuum film forming method such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. Among these, the sputtering method is preferable because the film forming chamber can be downsized and the film forming speed is high. Examples of the sputtering method include DC magnetron sputtering. A metal target can be used as the target.

  At least a part of the first metal oxide layer 12 and the second metal oxide layer 14 and at least a part of the metal layer 16 in the transparent conductor 100 may be removed by etching or the like.

  FIG. 2 is a schematic cross-sectional view showing another embodiment of the transparent conductor. The transparent conductor 101 is different from the transparent conductor 100 in that the transparent conductor 101 includes a pair of hard coat layers 20 so as to sandwich the transparent resin base material 10. Other configurations are the same as those of the transparent conductor 100.

  As the pair of hard coat layers 20, the transparent conductor 101 has a first hard coat layer 22 on the main surface on the first metal oxide layer 12 side of the transparent resin base material 10, and the first of the transparent resin base material 10. A second hard coat layer 24 is provided on the main surface opposite to the one metal oxide layer 12 side. That is, the transparent conductor 101 includes the second hard coat layer 24, the transparent resin substrate 10, the first hard coat layer 22, the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer. 14 has a laminated structure laminated in this order. The thickness, structure, and composition of the first hard coat layer 22 and the second hard coat layer 24 may be the same or different. Further, it is not always necessary to provide both the first hard coat layer 22 and the second hard coat layer 24, and only one of them may be provided.

  By providing the hard coat layer 20, scratches generated on the transparent resin substrate 10 can be sufficiently suppressed. The hard coat layer 20 contains a cured resin obtained by curing the resin composition. The resin composition preferably contains at least one selected from a thermosetting resin composition, an ultraviolet curable resin composition, and an electron beam curable resin composition. The thermosetting resin composition may include at least one selected from an epoxy resin, a phenoxy resin, and a melamine resin.

  A resin composition is a composition containing the sclerosing | hardenable compound which has energy-beam reactive groups, such as a (meth) acryloyl group and a vinyl group, for example. Note that the notation of (meth) acryloyl group includes at least one of acryloyl group and methacryloyl group. The curable compound preferably contains a polyfunctional monomer or oligomer containing 2 or more, preferably 3 or more energy ray reactive groups in one molecule.

  The curable compound preferably contains an acrylic monomer. Specific examples of acrylic monomers include 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, ethylene oxide-modified bisphenol A di (meth) acrylate, and trimethylolpropane tri (meth). Acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, trimethylolpropane propylene oxide modified tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta (meth) Acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, and 3- (meth) acryloyloxy Riserinmono (meth) acrylate. However, it is not necessarily limited to these. For example, urethane-modified acrylate and epoxy-modified acrylate are also included.

  As the curable compound, a compound having a vinyl group may be used. Examples of the compound having a vinyl group include ethylene glycol divinyl ether, pentaerythritol divinyl ether, 1,6-hexanediol divinyl ether, trimethylolpropane divinyl ether, ethylene oxide-modified hydroquinone divinyl ether, ethylene oxide-modified bisphenol A divinyl ether, Examples include pentaerythritol trivinyl ether, dipentaerythritol hexavinyl ether, and ditrimethylolpropane polyvinyl ether. However, it is not necessarily limited to these.

  The resin composition contains a photopolymerization initiator when the curable compound is cured by ultraviolet rays. Various photopolymerization initiators can be used. For example, it may be appropriately selected from known compounds such as acetophenone, benzoin, benzophenone, and thioxanthone. More specifically, Darocur 1173, Irgacure 651, Irgacure 184, Irgacure 907 (above trade name, manufactured by Ciba Specialty Chemicals) and KAYACURE DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) can be mentioned. .

  A photoinitiator should just be about 0.01-20 mass% or about 0.5-5 mass% with respect to the mass of a curable compound. The resin composition may be a known composition obtained by adding a photopolymerization initiator to an acrylic monomer. Examples of the acrylic monomer added with a photopolymerization initiator include SD-318 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.) and XNR5535 (trade name, Nagase Sangyo), which are ultraviolet curable resins. Etc.).

  The resin composition may contain organic fine particles and / or inorganic fine particles for increasing the strength of the coating film and / or adjusting the refractive index. Examples of the organic fine particles include organic silicon fine particles, crosslinked acrylic fine particles, and crosslinked polystyrene fine particles. Examples of the inorganic fine particles include silicon oxide fine particles, aluminum oxide fine particles, zirconium oxide fine particles, titanium oxide fine particles, and iron oxide fine particles. Of these, silicon oxide fine particles are preferred.

  The fine particles preferably have a surface treated with a silane coupling agent, and energy ray reactive groups such as (meth) acryloyl groups and / or vinyl groups are present in the form of a film on the surface. When fine particles having such reactivity are used, the fine particles react with each other upon irradiation with energy rays, or the fine particles and polyfunctional monomers or oligomers react to increase the strength of the film. . Silicon oxide fine particles treated with a silane coupling agent containing a (meth) acryloyl group are preferably used.

  The average particle diameter of the fine particles is smaller than the thickness of the hard coat layer 20 and may be 100 nm or less or 20 nm or less from the viewpoint of ensuring sufficient transparency. On the other hand, from the viewpoint of production of the colloidal solution, it may be 5 nm or more, or 10 nm or more. When organic fine particles and / or inorganic fine particles are used, the total amount of organic fine particles and inorganic fine particles may be, for example, 5 to 500 parts by mass, or 20 to 200 parts by mass with respect to 100 parts by mass of the curable compound. May be.

  When a resin composition that cures with energy rays is used, the resin composition can be cured by irradiation with energy rays such as ultraviolet rays. Accordingly, it is preferable to use such a resin composition from the viewpoint of the manufacturing process.

  The first hard coat layer 22 can be produced by applying a solution or dispersion of the resin composition onto one surface of the transparent resin substrate 10 and drying it to cure the resin composition. Application | coating in this case can be performed by a well-known method. Examples of the coating method include an extrusion nozzle method, a blade method, a knife method, a bar coating method, a kiss coating method, a kiss reverse method, a gravure roll method, a dip method, a reverse roll method, a direct roll method, a curtain method, and a squeeze method. Etc. The second hard coat layer 24 can also be produced on the other surface of the transparent resin substrate 10 in the same manner as the first hard coat layer 22.

  The thickness of the first hard coat layer 22 and the second hard coat layer 24 is, for example, 0.5 to 10 μm. If the thickness exceeds 10 μm, uneven thickness or wrinkles tend to occur. On the other hand, when the thickness is less than 0.5 μm, when the transparent resin substrate 10 contains a considerable amount of low molecular weight components such as plasticizers or oligomers, the bleeding out of these components can be sufficiently suppressed. It can be difficult. In addition, from the viewpoint of suppressing warpage, it is preferable that the thicknesses of the first hard coat layer 22 and the second hard coat layer 24 be approximately the same.

  The refractive indexes of the first hard coat layer 22 and the second hard coat layer 24 are, for example, 1.40 to 1.60. The absolute value of the difference in refractive index between the transparent resin substrate 10 and the first hard coat layer 22 is preferably 0.1 or less. The absolute value of the difference in refractive index between the transparent resin substrate 10 and the second hard coat layer 24 is also preferably 0.1 or less. The first hard coat layer 22 and the second hard coat layer 22 are reduced by reducing the absolute value of the difference in refractive index between the first hard coat layer 22 and the second hard coat layer 24 and the transparent resin substrate 10. It is possible to suppress the intensity of interference unevenness generated by the thickness unevenness of 24.

  The thickness of each layer constituting the transparent conductors 100 and 101 can be measured by the following procedure. The transparent conductors 100 and 101 are cut by a focused ion beam device (FIB, Focused Ion Beam) to obtain a cross section. The cross section is observed using a transmission electron microscope (TEM), and the thickness of each layer is measured. The measurement is preferably performed at 10 or more arbitrarily selected positions, and the average value is obtained. As a method for obtaining the cross section, a microtome may be used as an apparatus other than the focused ion beam apparatus. A scanning electron microscope (SEM) may be used as a method for measuring the thickness. It is also possible to measure the film thickness using a fluorescent X-ray apparatus.

  The thickness of the transparent conductors 100 and 101 may be 200 μm or less, or 150 μm or less. Such a thickness can sufficiently satisfy the required level of thinning. The total light transmittance of the transparent conductors 100 and 101 can be as high as 85% or more, for example. Further, the surface resistance value (four-terminal method) of the transparent conductors 100 and 101 is, for example, 30Ω / □ or less without thermal annealing of the first metal oxide layer 12 and the second metal oxide layer 14. And can be 25 Ω / □ or less.

  The transparent conductors 100 and 101 having the above-described configuration have a stacked structure in which the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are stacked. This laminated structure can be easily removed at once using a normal etching solution. In addition, it has high transmittance and high conductivity without thermal annealing. For this reason, it can use suitably for the sensor film use of a touch panel.

  FIG. 3 is a schematic cross-sectional view showing an enlarged part of a cross section of a touch panel 200 including a pair of sensor films. 4A and 4B are plan views of sensor films 100a and 100b using the transparent conductor 100 described above. The touch panel 200 includes a pair of sensor films 100 a and 100 b that are disposed to face each other via the optical glue 18. The touch panel 200 can calculate the touch position of the contact body as a coordinate position (horizontal position and vertical position) on a two-dimensional coordinate (XY coordinate) plane parallel to the panel board 70 serving as a screen. It is configured.

  Specifically, the touch panel 200 includes a sensor film 100a for longitudinal position detection (hereinafter referred to as “sensor film for Y”) and a sensor for position detection in the lateral direction, which are bonded together via the optical glue 18. A film 100b (hereinafter referred to as "sensor film for X"). On the lower surface side of the X sensor film 100b, a spacer 92 is provided between the X sensor film 100b and the panel plate 70 of the display device.

  A cover glass 19 is provided on the upper surface side (the side opposite to the panel plate 70 side) of the Y sensor film 100 a via an optical glue 17. That is, the touch panel 200 has a laminated structure in which the X sensor film 100b, the Y sensor film 100a, and the cover glass 19 are arranged in this order on the panel board 70 from the panel board 70 side.

  The Y sensor film 100a for detecting the vertical position and the X sensor film 100b for detecting the horizontal position are constituted by the transparent conductor 100 described above. The Y sensor film 100a and the X sensor film 100b have a sensor electrode 15a and a sensor electrode 15b, which are conductive portions, so as to face the cover glass 19.

  The sensor electrode 15 a includes a first metal oxide layer 12, a second metal oxide layer 14, and a metal layer 16. As shown in FIG. 4A, a plurality of sensor electrodes 15a extend in the vertical direction (y direction) so that the touch position in the vertical direction (y direction) can be detected. The plurality of sensor electrodes 15a are arranged in parallel to each other along the vertical direction (y direction). One end of the sensor electrode 15a is connected to the electrode 80 on the driving IC side via a conductor line 50 formed of silver paste.

  The X sensor film 100b that detects the lateral position has a sensor electrode 15b on the surface facing the Y sensor film 100a. The sensor electrode 15 b includes a first metal oxide layer 12, a second metal oxide layer 14, and a metal layer 16. As shown in FIG. 4B, a plurality of sensor electrodes 15b extend in the horizontal direction (x direction) so that the touch position in the horizontal direction (x direction) can be detected. The plurality of sensor electrodes 15b are arranged in parallel to each other along the horizontal direction (x direction). One end of the sensor electrode 15b is connected to an electrode 80 on the driving IC side through a conductor line 50 formed of silver paste.

  The Y sensor film 100a and the X sensor film 100b are optical glues so that the sensor electrodes 15a and 15b are orthogonal to each other when viewed from the stacking direction of the Y sensor film 100a and the X sensor film 100b. 18 are superimposed. A cover glass 19 is provided on the opposite side of the Y sensor film 100 a from the X sensor film 100 b side via an optical glue 17. As the optical glues 17, 18, the cover glass 19, and the panel plate 70, ordinary ones can be used.

  The conductor line 50 and the electrode 80 in FIGS. 4A and 4B are made of a conductive material such as metal (for example, Ag). The conductor line 50 and the electrode 80 are patterned by, for example, screen printing. The transparent resin base material 10 also has a function as a protective film that covers the surface of the touch panel 200.

  The shape and number of sensor electrodes 15a and 15b in each sensor film 100a and 100b are not limited to the forms shown in FIGS. 3, 4A, and 4B. For example, the detection accuracy of the touch position may be increased by increasing the number of sensor electrodes 15a and 15b.

  On the opposite side of the X sensor film 100b to the Y sensor film 100a side, a panel plate 70 is provided via a spacer 92. The spacer 92 can be provided at a position corresponding to the shape of the sensor electrodes 15a and 15b and a position surrounding the entire sensor electrodes 15a and 15b. The spacer 92 may be formed of a light-transmitting material, for example, PET (polyethylene terephthalate) resin. One end of the spacer 92 is bonded to the lower surface of the X sensor film 100b by an optical glue or an adhesive 90 having translucency such as acrylic or epoxy. The other end of the spacer 92 is bonded to the panel plate 70 of the display device with an adhesive 90. Thus, by arranging the X sensor film 100b and the panel plate 70 to face each other via the spacer 92, a gap S can be provided between the X sensor film 100b and the panel plate 70 of the display device.

  A control unit (IC) is electrically connected to the electrode 80. The capacitance changes of the sensor electrodes 15a and 15b caused by the capacitance change between the fingertip and the Y sensor film 100a of the touch panel 200 are measured. The control unit can calculate the touch position of the contact body as a coordinate position (intersection of the position in the X-axis direction and the position in the Y-axis direction) based on the measurement result. In addition to the above, various known methods can be adopted as the sensor electrode driving method and the coordinate position calculation method.

  The touch panel 200 can be manufactured by the following procedure. After preparing the transparent conductor 100, the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are etched and patterned. Specifically, a resist material is applied to the surface of the second metal oxide layer 14 by spin coating using a photolithography technique. Thereafter, pre-baking may be performed to improve adhesion. Subsequently, a resist pattern is formed by arranging and exposing a mask pattern and developing with a developer. The formation of the resist pattern is not limited to photolithography, and can be formed by screen printing or the like.

  Next, the transparent conductor 100 on which the resist pattern is formed is immersed in an acidic etching solution, and the first metal oxide layer 12, the second metal oxide layer 14, and the metal in the portion where the resist pattern is not formed. Layer 16 is dissolved away. Thereafter, the resist is removed, and the Y sensor film 100a on which the sensor electrode 15a is formed and the X sensor film 100b on which the sensor electrode 15b is formed are obtained.

  If the first metal oxide layer 12 and the second metal oxide layer 14 have different compositions, and the first metal oxide layer 12 has a composition that is not removed by etching, the metal layer 16 and the second metal oxide layer It is also possible to etch the physical layer 14 together and leave the first metal oxide layer 12 as it is after etching. As the etchant, an inorganic acid-based etchant can be used. For example, a phosphoric acid-based etching solution is suitable.

  Subsequently, for example, a metal paste such as a silver alloy paste is applied to form the conductor line 50 and the electrode 80. In this way, the control unit and the sensor electrodes 15a and 15b are electrically connected. Next, the Y sensor film 100a and the X sensor film 100b are bonded using the optical glue 18 so that the sensor electrodes 15a and 15b face in the same direction. In this case, the sensor electrodes 15a and 15b are bonded so as to be orthogonal to each other when viewed from the stacking direction of the Y sensor film 100a and the X sensor film 100b. Then, the cover glass 19 and the Y sensor film 100 a are bonded together using the optical glue 17. In this way, the touch panel 200 can be manufactured.

  The touch panel 200 uses the transparent conductor 100 as the Y sensor film 100a and the X sensor film 100b. The transparent conductor 100 can collectively remove the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 by etching. For this reason, the manufacturing process of the touch panel 200 can be simplified and the touch panel 200 can be easily manufactured.

  In addition, it is not necessary to use the transparent conductor 100 for both the Y sensor film 100a and the X sensor film 100b, and either one may use another transparent conductor. Even with such a touch panel, the display can be made sufficiently clear. Moreover, you may use the transparent conductor 101 instead of the transparent conductor 100 as a sensor film.

  Thus, the transparent conductors 100 and 101 can be suitably used for touch panels. However, the use is not limited to the touch panel. For example, the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 are processed into a predetermined shape by etching, and the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 are processed. A portion (conductive portion) having the metal oxide layer 12, the second metal oxide layer 14 and the metal layer 16, and the first metal oxide layer 12, the second metal oxide layer 14 and the metal layer 16 are provided. In various display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence panel (organic EL, inorganic EL), electrochromic element, and electronic paper, It can be used for transparent electrodes, antistatics, and electromagnetic wave shields. It can also be used as an antenna.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, the above-described transparent conductor 101 has the pair of hard coat layers 20, but may include only one of the first hard coat layer 22 and the second hard coat layer 24. Further, a hard coat layer may be provided on one surface of the transparent resin base material 10, and a plurality of optical adjustment layers may be provided by coating on the other surface. In this case, the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 may be provided on the optical adjustment layer. Furthermore, the transparent conductors 100 and 101 may be provided with an arbitrary layer at an arbitrary position other than the above-described layers as long as the function is not greatly impaired.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Examples 1 to 18]
(Preparation of transparent conductor 101)
A transparent conductor as shown in FIG. 2 was produced. The transparent conductor has a laminated structure in which a transparent resin base material sandwiched between a pair of hard coat layers, a first metal oxide layer, a metal layer, and a second metal oxide layer are laminated in this order. It was. The transparent conductor of each Example was produced as follows.

A polyethylene terephthalate film (manufactured by Toray Industries, Inc., product number: U48) having a thickness of 100 μm was prepared. This PET film was used as a transparent resin substrate. On the transparent resin substrate, a first metal oxide layer, a metal layer, and a second metal oxide layer were sequentially formed by DC magnetron sputtering. The first metal oxide layer and the second metal oxide layer were formed using a ZnO—Ga ₂ O ₃ —GeO ₂ target having the composition shown in Table 1. The first metal oxide layer and the second metal oxide layer in each example were formed using targets having the same composition. The compositions of the first metal oxide layer and the second metal oxide layer in each example were as shown in Table 1. The thickness of the first metal oxide layer and the second metal oxide layer in each example was 50 nm.

  In all the examples shown in Table 1, the metal layer was formed using an AgPdCu (Ag: Pd: Cu = 99.0: 0.5: 0.5 (mass%)) target. The thickness of the metal layer 16 was 5 nm.

(Evaluation of transparent conductor 101)
The etching characteristics were evaluated by the following procedure. First, a PAN-based etching solution containing phosphoric acid, acetic acid, and nitric acid was prepared. Etching was performed by immersing the transparent conductor of each example in this etching solution at room temperature for 1 minute. Then, the total light transmittance measurement was performed and it was determined whether the 1st metal oxide layer, the metal layer, and the 2nd metal oxide layer were melt | dissolved. Specifically, when the total light transmittance of the sample after etching coincided with the total light transmittance of only the transparent resin substrate, it was determined as “A”, and when it did not coincide, “B” was determined. The total light transmittance (transmittance) was measured using a haze meter (trade name: NDH-7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The evaluation results are as shown in Table 1.

  The surface resistance of each example was measured using a 4-terminal resistivity meter (trade name: Loresta GP, manufactured by Mitsubishi Chemical Corporation). The results are shown in Table 1. In Table 1, “surface resistance (1)” is a surface resistance value before storing the transparent conductor in an environment of 85 ° C. and 85% RH (relative humidity 85%) for 50 hours. ")" Is the surface resistance value after storage in the above environment.

  After storing the transparent conductor of each Example in an environment of 85 ° C. and 85% RH, the storage stability was evaluated visually. When white turbidity was observed in the transparent conductor, it was determined as “B”, and when it was not observed as “A”. The results were as shown in Table 1.

  As shown in Table 1, in all Examples, the evaluation of the etching characteristics was “A”. From this, it was confirmed that the metal oxide layer and the metal layer in the transparent conductors of Examples 1 to 18 can be easily removed. The transparent conductor of Example 10 had the highest total light transmittance, but the storage stability was evaluated as B. The surface resistance after storage in a high temperature and high humidity environment was also high. This is because the conductivity of the second metal oxide layer that contacts the four terminals of the surface resistance measuring instrument has decreased. For this reason, in the use which does not need to attach a wiring electrode to the 2nd metal oxide layer and to make it conduct, even if surface resistance (2) is high, it does not become a problem practically. In addition, the storage stability is a level that can be sufficiently used for applications such as a noise sheet (for example, a noise shield) that do not require a very high level of transparency.

  In order to evaluate the characteristics of the metal oxide layer, a sample of only the metal oxide layer (single layer) was prepared in the same manner as described above. This sample was evaluated in the same manner as described above. The evaluation results are shown in Table 2. In addition, the absorptance of Table 2 is a value obtained by the equation of 100−transmittance−reflectance = absorbance using the measurement results of transmittance and reflectance measured using a spectroscope. This absorptance is a value at a wavelength of 380 nm.

As shown in Table 1, it was confirmed that the metal oxide layer of each Example has a sufficiently low absorption rate. Further, also contain ZnO as the main component, by the inclusion of _Ga 2 _{O 3} and GeO ₂ as an auxiliary component, it was confirmed that the improved corrosion resistance.

[Examples 19 to 30]
The composition of the target at the time of producing the metal layer was changed, and as shown in Table 3, the composition of the metal layer was changed and / or the thickness of the metal layer was changed as in Example 6. Thus, a transparent conductor was produced. That is, in Examples 19 to 26, the thickness of the metal layer was changed. In Example 27, a metal layer was formed using an AgNdCu (Ag: Nd: Cu = 99.0: 0.5: 0.5 (mass%)) target. In Example 28, a metal layer was formed using an AgInSn (Ag: In: Sn = 99.0: 0.5: 0.5 (mass%)) target. In Example 29, a metal layer was formed using an AgSnSb (Ag: Sn: Sb = 99.0: 0.5: 0.5 (mass%)) target. In Example 30, the metal layer was formed using an AgCu (Ag: Cu = 99.5: 0.5 (mass%)) target.

  The produced transparent conductors of Examples 19 to 30 were evaluated in the same manner as in Example 6. The evaluation results are as shown in Table 3. In addition, the composition and thickness of the metal oxide layers of Examples 19 to 30 are the same as those of Example 6. In addition, the storage stability was performed under the conditions of storing in an environment of 85 ° C. and 85% RH for 50 hours and under the condition of storing in an environment of 60 ° C. and 90% RH for 50 hours. After storage under each condition, it was determined as “B” when the transparent conductor was visually observed as “B”, and when not observed as “A”.

  From the results shown in Table 3, the evaluation of the etching characteristics was “A” in any of the examples. From this, it was confirmed that the metal oxide layer and the metal layer in the transparent conductors of Examples 19 to 30 can be easily removed. Moreover, the tendency for surface resistance to become small and the tendency for total light transmittance to fall was confirmed when the thickness of the metal layer became large. In addition, when the silver alloy contains Pd, it was confirmed that the storage stability is particularly excellent.

[Comparative Examples 1-4]
Comparative Example 1 to Comparative Example 1 except that a target having the composition shown in Table 4 was used as a target when forming the first metal oxide layer and the second metal oxide layer. 4 transparent conductors were produced. In Comparative Example 1, the first metal oxide layer and the second metal oxide layer were formed using a ZnO—TiO ₂ —Nb ₂ O ₅ target. In Comparative Example 2, a ZnO—In ₂ O ₃ —Cr ₂ O ₃ target was used. In Comparative Example 3, a ZnO—SnO ₂ —In ₂ O ₃ target was used. In Comparative Example 4, a ZnO—SnO ₂ —Cr ₂ O ₃ target was used. In each comparative example, the first metal oxide layer and the second metal oxide layer were formed using targets having the same composition. The compositions of the first metal oxide layer and the second metal oxide layer in each comparative example were as shown in Table 4. The etching characteristics of the transparent conductor of each comparative example were evaluated in the same manner as in Example 1. The results were as shown in Table 4.

As shown in Table 4, it was confirmed that the transparent conductor having a metal oxide layer not containing the three components of ZnO—Ga ₂ O ₃ —GeO ₂ could not be etched sufficiently.

  According to the present disclosure, a transparent conductor that can easily remove a metal oxide layer and a metal layer by etching is provided. Moreover, according to this indication, the touch panel which can be manufactured easily is provided by using such a transparent conductor.

  DESCRIPTION OF SYMBOLS 10 ... Transparent resin base material, 12 ... 1st metal oxide layer, 14 ... 2nd metal oxide layer, 16 ... Metal layer, 15a, 15b ... Sensor electrode, 20 ... Hard-coat layer, 22 ... 1st Hard coat layer, 24 ... second hard coat layer, 50 ... conductor line, 70 ... panel plate, 80 ... electrode, 90 ... adhesive, 92 ... spacer, 100, 101 ... transparent conductor, 100a ... sensor film for Y , 100b ... Sensor film for X, 200 ... Touch panel.

Claims (6)

A transparent resin substrate, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer are laminated in this order,
The second metal oxide layer is a transparent conductor containing ZnO as a main component and Ga ₂ O ₃ and GeO ₂ as subcomponents. In the second metal oxide layer,
ZnO content with respect to the total of the three components of ZnO, Ga ₂ O ₃ and GeO ₂ is 70 to 90 mol%,
The content of Ga ₂ O ₃ with respect to the total of the three components is 5 to 15 mol%,
The 3 content of GeO ₂ with respect to the sum of the components is 5 to 20 mol%, the transparent conductor of claim 1.   The transparent conductor according to claim 1 or 2, wherein the metal layer has a thickness of 4 to 11 nm. The first metal oxide layer contains ZnO as a main component, containing _Ga 2 _{O 3} and GeO ₂ as an auxiliary component, the transparent conductor according to any one of claims 1 to 3.   The transparent conductive according to any one of claims 1 to 4, wherein the silver alloy is an alloy of Ag and at least one metal selected from the group consisting of Pd, Cu, Nd, In, Sn, and Sb. body. A touch panel having a sensor film on a panel board,
The touch panel with which the said sensor film is comprised with the transparent conductor as described in any one of Claims 1-5.

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