JP5786403B2 - Transparent conductive laminate and touch panel using the same - Google Patents

Description

  The present invention relates to a transparent conductive laminate used as an electrode material of a transparent touch panel that is an input device.

  In recent years, a transparent touch panel is attached as an input device on the display of various electronic devices. Examples of the touch panel system include a resistance film type and a capacitance type. In the resistive film type, the touch position is detected by contacting the upper and lower electrodes. In the capacitance type, the touch position is detected by a change in the surface capacitance when a fingertip or the like touches.

  Due to the thin frame of liquid crystal panels and the diversification of usage environments, high durability of touch panels incorporated in displays is required. For that purpose, high durability of the transparent conductive laminated body used as an electrode is indispensable (for example, patent document 1). Examples of a method for making the transparent conductive laminate highly durable include a method of providing an adhesion layer and a cushion layer between the base material and the transparent conductive film (for example, Patent Document 2).

  On the other hand, because of the diversification of usage environments such as the increase in cases used outdoors due to adoption in mobile phones and the like in recent years, the transparent conductive laminate used for touch panels has only mechanical durability against pen touch etc. In addition, weather resistance against environmental changes such as sunlight is also required.

  In order to obtain mechanical durability and weather resistance, it is necessary to further increase the adhesion between the substrate and the transparent conductive film of the transparent conductive laminate. If this adhesion force is small, the transparent conductive film is peeled off from the substrate due to the influence of pen touch or environmental change, and performance such as electrical characteristics and optical characteristics is lost.

Japanese Patent Laid-Open No. 2007-213886 JP 2009-218034 A

  Therefore, for example, as described in Patent Document 2, when an adhesion layer or a cushion layer is provided between the base material and the transparent conductive film, the adhesion force between the base material and the transparent conductive film can be increased to some extent. It is. However, in order to satisfy mechanical durability and weather resistance, it is necessary to further increase the adhesion.

  Accordingly, the present invention is intended to solve the above-described problems of the prior art, and an object thereof is to provide a transparent conductive laminate satisfying both mechanical durability and weather resistance.

As means for solving the above problems, the present invention includes at least a transparent base material, an adhesion layer provided on one surface of the transparent base material, an optical adjustment layer, and a transparent conductive film in this order. A transparent conductive laminate, wherein the adhesion layer includes at least a first adhesion layer made of silicon oxide and a second adhesion layer made of aluminum oxide .

Further, the present invention, the adhesion layer is a transparent conductive laminate permeable you comprises a metal or an inorganic compound.

Further, the present invention, the thickness of the adhesive layer is a transparent conductive laminate permeable you wherein a is 0.1nm or 10nm or less.

Further, the present invention, the adhesion layer is a transparent conductive laminate permeable you being a layer for improving the adhesion between the transparent conductive film and the transparent substrate.

Moreover, this invention is a touch panel using the transparent conductive laminated body as described in this invention as an electrode material.

  According to the present invention, by providing an adhesive layer composed of at least two layers on one surface of a transparent substrate, the adhesion between the transparent substrate and the transparent conductive film is improved, and the mechanical properties of the transparent conductive laminate are improved. Durability and weather resistance can be improved.

It is explanatory drawing of the cross section of the transparent conductive laminated body of the 1st Embodiment of this invention. It is explanatory drawing of the cross section of the transparent conductive laminated body of the 2nd Embodiment of this invention. It is explanatory drawing of the cross section of the transparent conductive laminated body of the 3rd Embodiment of this invention. It is explanatory drawing of the cross section of the transparent conductive laminated body of the 4th Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and modifications such as design changes can be made based on the knowledge of those skilled in the art, and such modifications have been added. Embodiments are also included in the scope of the present invention.

  Drawing 1 is an explanatory view of the section of the transparent conductive layered product of a 1st embodiment of the present invention. The transparent conductive laminate 10 includes a transparent substrate 1, a transparent conductive film 2, and an adhesion layer 3.

  Drawing 2 is an explanatory view of the section of the transparent conductive layered product of a 2nd embodiment of the present invention. The transparent conductive laminate 20 has a configuration in which the optical adjustment layer 4 is provided between the adhesion layer 3 and the transparent conductive film 2 of the transparent conductive laminate 10 shown in FIG.

  Drawing 3 is an explanatory view of the section of the transparent conductive layered product of a 3rd embodiment of the present invention. The transparent conductive laminate 30 has a configuration in which the resin layer 5 is provided between the transparent substrate 1 and the adhesion layer 3 of the transparent conductive laminate 10 shown in FIG.

  FIG. 4 is an explanatory view of a cross section of the transparent conductive laminate according to the fourth embodiment of the present invention. The transparent conductive laminate 40 has a configuration in which the optical adjustment layer 4 is provided between the transparent conductive film 2 and the adhesion layer 3 of the transparent conductive laminate 30 shown in FIG.

  The transparent conductive laminate 10, 20, 30, 40 according to the embodiment of the present invention is transparent between the transparent substrate 1 and the transparent conductive film 2, as shown in FIGS. An adhesion layer 3 for improving adhesion between the conductive film 2 is provided. When the adhesion layer 3 provided between the transparent substrate 1 and the transparent conductive film 2 is composed of at least two layers, the adhesion between the transparent substrate 1 and the transparent conductive film 2 is improved and mounted on the touch panel. The durability of both mechanical durability and weather resistance can be enhanced.

  As the transparent substrate 1 used in the present invention, a plastic film made of resin is used in addition to glass. The plastic film is not particularly limited as long as it has sufficient strength in the film-forming process and the post-process and has good surface smoothness. For example, polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polycarbonate Examples include films, polyethersulfone films, polysulfone films, polyarylate films, cyclic polyolefin films, polyimide films, and the like. The thickness is about 10 μm or more and 200 μm or less in consideration of the thinning of the member and the flexibility of the laminate.

  As the material contained in the transparent substrate 1, various known additives and stabilizers such as antistatic agents, plasticizers, lubricants, and easy adhesives may be used. In order to improve adhesion with each layer, corona treatment, low temperature plasma treatment, ion bombardment treatment, chemical treatment, etc. may be performed as pretreatment.

  Examples of the material used for the adhesion layer 3 used in the present invention include metals such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium, or 2 of these elements. Examples thereof include compounds composed of more than one kind, oxides, fluorides, sulfides and nitrides of these elements, or mixtures of these oxides, fluorides, sulfides and nitrides. Of the above materials, the chemical composition of oxides, fluorides, sulfides, and nitrides may not match the stoichiometric composition as long as adhesion is improved. Note that in this specification, a compound composed of two or more of the above elements, or an oxide, fluoride, sulfide, nitride, or oxide, fluoride, sulfide, or nitride of the above element. All of these mixtures are inorganic compounds.

  The adhesion layer 3 is preferably composed of two or more layers using the above materials. For example, in the order from the transparent substrate 1 side, a first layer formed using silicon oxide, aluminum oxide, chromium oxide, or the like, and a different material from the first layer such as silicon oxide, aluminum oxide, chromium oxide, or the like are used. The adhesion layer 3 can be formed by combining the second layer formed in this manner. In particular, the adhesion layer 3 is more preferably a combination of a first layer formed using silicon oxide and a second layer formed using aluminum oxide.

  The thickness of the adhesion layer 3 is preferably 0.1 nm or more and 10 nm or less as a whole of two or more layers constituting the adhesion layer 3. When the film thickness of the adhesion layer 3 is less than 0.1 nm, it becomes difficult to obtain film uniformity, and sufficient adhesion is not exhibited. Moreover, when the film thickness of the adhesion layer 3 exceeds 10 nm, the transparency is greatly lowered. Moreover, the thickness of each layer which comprises the contact | adherence layer 3 is suitably set by the material characteristic etc. of the transparent base material and transparent conductive film which are used.

  The resin layer 5 used in the present invention is provided to give the transparent conductive laminates 10, 20, 30, and 40 mechanical strength. Although it does not specifically limit as resin used, Resin which has transparency, moderate hardness, and mechanical strength is preferable. Specifically, a photocurable resin such as a monomer or a crosslinkable oligomer having a tri- or higher functional acrylate as a main component that can be expected to be three-dimensionally cross-linked is preferable.

  Trifunctional or higher acrylate monomers include trimethylolpropane triacrylate, isocyanuric acid EO-modified triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate Ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, polyester acrylate and the like are preferable. Particularly preferred are isocyanuric acid EO-modified triacrylates and polyester acrylates. These may be used alone or in combination of two or more. In addition to these tri- or higher functional acrylates, so-called acrylic resins such as epoxy acrylate, urethane acrylate, and polyol acrylate can be used in combination.

  As the crosslinkable oligomer, acrylic oligomers such as polyester (meth) acrylate, polyether (meth) acrylate, polyurethane (meth) acrylate, epoxy (meth) acrylate, and silicone (meth) acrylate are preferable. Specific examples include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bisphenol A type epoxy acrylate, polyurethane diacrylate, and cresol novolac type epoxy (meth) acrylate.

  In addition, the resin layer 5 may contain additives such as particles and a photopolymerization initiator.

  Examples of the particles to be added include organic or inorganic particles, but it is preferable to use organic particles in consideration of transparency. Examples of the organic particles include particles made of acrylic resin, polystyrene resin, polyester resin, polyolefin resin, polyamide resin, polycarbonate resin, polyurethane resin, silicone resin, and fluorine resin.

  The average particle size of the particles varies depending on the thickness of the resin layer 5, but for reasons of appearance such as haze, the lower limit is 2 μm or more, more preferably 5 μm or more, and the upper limit is 30 μm or less, preferably 15 μm or less. To do. Further, for the same reason, the particle content is preferably 0.5% by weight or more and 5% by weight or less based on the resin.

  When a photopolymerization initiator is added, radical generating photopolymerization initiators include benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyl methyl ketal, acetophenone, 2, 2 , -Dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, and other acetophenones, methylanthraquinone, 2-ethylanthraquinone, 2-amylanthraquinone and other anthraquinones, thioxanthone, 2,4-diethylthioxanthone, 2, 4 -Thioxanthones such as diisopropylthioxanthone, ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal, benzophenone, 4,4-bismeth Le benzophenones such aminobenzophenone and azo compounds, and the like. These can be used alone or as a mixture of two or more thereof, and further, tertiary amines such as triethanolamine and methyldiethanolamine, benzoic acid derivatives such as 2-dimethylaminoethylbenzoic acid and ethyl 4-dimethylaminobenzoate, etc. It can be used in combination with a photoinitiator aid or the like.

  The addition amount of the photopolymerization initiator is 0.1% by weight or more and 5% by weight or less, and preferably 0.5% by weight or more and 3% by weight or less with respect to the main component resin. Less than the lower limit is not preferable because the hard coat layer is insufficiently cured. Moreover, when exceeding an upper limit, since yellowing of a hard-coat layer will be produced or a weather resistance will fall, it is unpreferable. The light used for curing the photocurable resin is ultraviolet rays, electron beams, or gamma rays, and in the case of electron beams or gamma rays, it is not always necessary to contain a photopolymerization initiator or a photoinitiating aid. As these radiation sources, high pressure mercury lamps, xenon lamps, metal halide lamps, accelerated electrons, and the like can be used.

  The thickness of the resin layer 5 is not particularly limited, but is preferably in the range of 0.5 μm to 15 μm. Moreover, it is more preferable that the refractive index is the same as or close to that of the transparent substrate 1, and preferably about 1.45 or more and 1.75 or less.

  The resin layer 5 is formed by dissolving a resin as a main component in a solvent, a die coater, curtain flow coater, roll coater, reverse roll coater, gravure coater, knife coater, bar coater, spin coater, micro gravure coater, etc. The well-known coating method is used.

  The solvent is not particularly limited as long as it dissolves the main component resin and the like. Specifically, as a solvent, ethanol, isopropyl alcohol, isobutyl alcohol, benzene, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, methyl cellosolve, ethyl cellosolve, Examples include butyl cellosolve, methyl cellosolve acetate, and propylene glycol monomethyl ether acetate. These solvents may be used alone or in combination of two or more.

  The optical adjustment layer 4 has a function of adjusting the transmittance and hue of the transparent conductive laminate, and is a layer for improving visibility. When an inorganic compound is used as the optical adjustment layer 2, materials such as oxide, sulfide, fluoride, and nitride can be used. The thin film made of the inorganic compound has a different refractive index depending on the material, and the optical characteristics can be adjusted by forming a thin film having a different refractive index with a specific film thickness. The number of optical functional layers may be a plurality of layers depending on the target optical characteristics.

  Materials having a low refractive index include magnesium oxide (1.6), silicon dioxide (1.5), magnesium fluoride (1.4), calcium fluoride (1.3 to 1.4), cerium fluoride ( 1.6), aluminum fluoride (1.3), and the like. Moreover, as a material with a high refractive index, titanium oxide (2.4), zirconium oxide (2.4), zinc sulfide (2.3), tantalum oxide (2.1), zinc oxide (2.1), Examples include indium oxide (2.0), niobium oxide (2.3), and tantalum oxide (2.2). However, the numerical value in the parenthesis represents the refractive index.

  Examples of the transparent conductive film 2 include indium oxide, zinc oxide, and tin oxide, or two or three kinds of mixed oxides thereof, and those added with other additives. -Various materials can be used depending on the application, and are not particularly limited. At present, the most reliable and proven material is indium tin oxide (ITO).

  When indium tin oxide (ITO), which is the most common transparent conductive film, is used as the transparent conductive film 2, the content ratio of tin oxide doped in indium oxide is selected according to the specifications required for the device. To do. For example, when the transparent substrate is a plastic film, the sputtering target material used for crystallizing the thin film for the purpose of increasing the mechanical strength preferably has a tin oxide content of less than 10% by weight. In order to give flexibility, the content ratio of tin oxide is preferably 10% by weight or more. Moreover, when low resistance is calculated | required by a thin film, the content rate of a tin oxide has the preferable range of 2 to 20 weight%.

  As a manufacturing method of the optical adjustment layer 4 and the transparent conductive film 2, any film forming method may be used as long as the film thickness can be controlled, and a thin film forming dry method is particularly preferable. For this, a vacuum vapor deposition method, a physical vapor deposition method such as sputtering, or a chemical vapor deposition method such as a CVD method can be used. In particular, in order to form a thin film having a uniform film quality over a large area, a sputtering method in which the process is stable and the thin film becomes dense is preferable.

  Next, examples and comparative examples will be described.

<Example>
A polyethylene terephthalate (PET) film (188 μm) was used as a transparent substrate, and 3 nm of silicon oxide was formed as an adhesion layer on one surface of the PET film by sputtering, and 3 nm of aluminum oxide was further formed. Subsequently, a transparent conductive laminate in which silicon oxide and niobium oxide were formed as an optical adjustment layer and ITO was formed as a transparent conductive film was formed by a sputtering method.
<Comparative example>
A PET film (188 μm) was used as a transparent substrate, and an aluminum oxide film having a thickness of 3 nm was formed as an adhesion layer on one surface of the PET film by a sputtering method. Subsequently, a transparent conductive laminate in which silicon oxide and niobium oxide were formed as an optical adjustment layer and ITO was formed as a transparent conductive film was formed by a sputtering method.

[Weather resistance test]
For the weather resistance test, ATLAS Xenon Weatherometer Ci4000 (manufactured by Toyo Seiki Seisakusho) was used. The conditions were set as follows.
Illuminance: 1.2 W / m ² (420 nm)
Black standard panel temperature: 40 ℃
Tank temperature: 20 ° C
Humidity in the tank: 50% RH
Test time: 90 hours A weather resistance test was performed on each of the transparent conductive laminates prepared in Examples and Comparative Examples under the above conditions.

[Evaluation of adhesive strength of transparent conductive film (Crosscut tape peel evaluation)]
The surface of the transparent conductive laminate after the weather resistance test was cut on the surface of the transparent conductive film with a cutter knife, and a cellophane tape (manufactured by Nichiban) was applied, and the surface after peeling the cellophane tape was observed. Then, the number of grids where the transparent conductive film was peeled off was counted. The adhesion was compared by the number of squares peeled off.

  Table 1 shows the results of cross-cut tape peel evaluation after the weather resistance test. In the comparative example, peeling of 6 to 24 squares occurred, whereas in the example, no peeling occurred. It was confirmed that the production method of the example had improved durability against the weather resistance test as compared with the production method of the comparative example.

  The present invention is used for a transparent touch panel attached as an input device on a display of an electronic device. In particular, it is used for mobile devices capable of multi-touch.

DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... Transparent conductive film 3 ... Adhesion layer 4 ... Optical adjustment layer 5 ... Resin layer 10, 20, 30, 40 ... Transparent conductive laminated body

Claims (4)

At least, a transparent conductive laminate comprising a transparent substrate, an adhesion layer provided on one surface of the transparent substrate, an optical adjustment layer, and a transparent conductive film in this order,
The transparent conductive laminate, wherein the adhesion layer includes at least a first adhesion layer made of silicon oxide and a second adhesion layer made of aluminum oxide .   The transparent conductive laminate according to claim 1, wherein the adhesion layer has a thickness of 0.1 nm to 10 nm. The adhesion layer, a transparent electroconductive laminate according to claim 1 or 2, characterized in that a layer for improving the adhesion between the transparent conductive film and the transparent substrate. A touch panel using the transparent conductive laminate according to any one of claims 1 to 3 as an electrode material.

Images