TWI595392B - Transparent conductive body and touch panel - Google Patents

Description

Transparent conductor and touch panel

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

The transparent conductor is used as a display such as a liquid crystal display (LCD), a plasma display panel (PDP), and an electroluminescence panel (organic EL, inorganic EL), and a transparent electrode of a solar cell or the like. Further, in addition to these, it is also used for an electromagnetic wave shielding film, an infrared shielding film, and the like. As a material of 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 touch panels, such as smart phones and tablet terminals, are rapidly spreading. These have a configuration in which a touch sensor portion is provided on a liquid crystal panel and a cover glass is provided on the outermost surface. The touch sensor unit is configured by laminating one or two sheets of an ITO film formed by sputtering on one side or both sides of a glass or a film substrate.

With the increase in the size of the touch panel and the high precision of the touch sensor function, a transparent conductor having high transmittance and low resistance has been sought. In order to lower the electric resistance of the transparent electric conductor using the ITO film, it is necessary to thicken the thickness of the ITO film or to perform crystallization of the ITO film by thermal annealing. However, when the ITO film is thickened, the transmittance is lowered. In addition, it is generally difficult to subject the film substrate to thermal annealing at a high temperature. Therefore, in the case of the ITO film provided on the film substrate, it is difficult to maintain a high transmittance and reduce the electric resistance.

In this case, a transparent conductive film having a laminated structure of a metal oxide layer and a metal layer containing zinc oxide as a main component is proposed (for example, Japanese Patent Laid-Open No. Hei 9-291355 Bulletin).

In the use of a touch panel or the like, the transparent conductive film is patterned into a conductive portion and an insulating portion and the position of the touch is detected. Therefore, in the transparent conductor having a laminated structure of a metal oxide layer and a metal layer, the metal oxide layer and the metal layer can be removed at one time by etching. However, in the laminated structure of the metal oxide layer and the metal layer containing zinc oxide as a main component, there is a case where it is difficult to remove the metal oxide layer and the metal layer at one time by etching.

Here, in the present disclosure, there is provided a transparent conductor having a laminated structure of a metal oxide layer containing a zinc oxide as a main component and a metal layer, and the metal oxide layer and the metal layer can be easily removed by etching. Further, in the present disclosure, a touch panel which can be easily manufactured is provided by using such a transparent conductor.

The present invention provides a transparent conductor in which 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 the above-described order, and the second metal is provided. The oxide layer contains ZnO as a main component and contains Ga ₂ O ₃ and GeO ₂ as a subcomponent.

Such a transparent conductor has a laminated structure and includes a second metal oxide layer containing ZnO as a main component and containing Ga ₂ O ₃ and GeO ₂ as a subcomponent, and a metal layer containing a silver alloy. The second metal oxide layer and the metal layer are easily removed at one time by etching. In addition, a transparent conductor having high transparency, high electrical conductivity, and excellent corrosion resistance can be produced. Therefore, it can be applied to applications requiring etching such as a touch panel.

In some embodiments, the content of ZnO may be 70 to 90 mol% based on the total of the three components of ZnO, Ga ₂ O ₃ and GeO ₂ in the second metal oxide layer. The Ga ₂ O ₃ content may be 5 to 15 mol% with respect to the total of the above three components. The content of GeO ₂ may be 5 to 20 mol% based on the total of the above three components. By containing the above ratio ZnO, Ga ₂ O ₃ and GeO _2, it is possible to sufficiently improve the transparency of the second metal oxide layers, conductive, corrosion resistance and etch resistance.

In the form of several embodiments, the first metal oxide layer as a main component may contain ZnO, and may contain a subcomponent Ga ₂ O ₃ and GeO _2. Thereby, the first metal oxide layer, the second metal oxide layer, and the metal layer can be easily removed at one time by etching. In addition, a transparent conductor having high transparency, high electrical conductivity, and excellent corrosion resistance can be produced.

In several embodiments, the metal layer may have a thickness of 4 to 11 nm. The transparency of the transparent conductor can be sufficiently improved and the surface resistance can be lowered. 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 sensing film on the panel, the sensing film being composed of the transparent conductor. Since such a touch panel has a sensing film made of the above transparent conductor, it can be easily manufactured.

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

10‧‧‧Transparent resin substrate

12‧‧‧1st metal oxide layer

14‧‧‧2nd metal oxide layer

15a, 15b‧‧‧ sensor electrodes

16‧‧‧metal layer

17, 18‧‧‧ optical glue

19‧‧‧ Covering glass

20‧‧‧hard coating

22‧‧‧1st hard coat

24‧‧‧2nd hard coat

50‧‧‧Conductor lines

70‧‧‧ panel

80‧‧‧ electrodes

90‧‧‧Adhesive

92‧‧‧shims

100, 101‧‧‧ Transparent conductor

100a, 100b‧‧‧ sensing film

200‧‧‧ touch panel

S‧‧‧ gap

Fig. 1 is a cross-sectional view schematically showing an embodiment of a transparent conductor.

Fig. 2 is a cross-sectional view schematically showing another embodiment of a transparent conductor.

Fig. 3 is a schematic cross-sectional view showing a portion of a cross section in an embodiment of the touch panel.

4(A) and 4(B) are plan views showing a sensing film of an embodiment of the touch panel.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments at all. In the drawings, the same or equivalent components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

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 the film-shaped transparent resin substrate 10, the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are arranged in the above-described order.

"Transparent" in this specification means that visible light is transmitted, and light can be scattered to some extent. The degree of light scattering varies depending on the level required for the use of the transparent conductor 100. The term "transparent" as used in this specification is also encompassed by what is commonly referred to as translucent light scattering. The degree of light scattering is preferably relatively small, and the transparency is preferably relatively 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. The total light transmittance is a transmittance including diffused transmitted light obtained by using an integrating sphere, and can be measured using a commercially available film haze meter.

The transparent resin substrate 10 is not particularly limited, and may be a flexible organic resin film. The organic resin film may also be an organic resin sheet. Examples of the organic resin film include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, and polycarbonate films. An acrylic film, a norbornene film, a polyarylate film, a polyether ruthenium film, a diethyl ruthenium cellulose film, a triethylene fluorene cellulose film, or the like. Among these, a polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is preferable.

The transparent resin substrate 10 is preferably thicker from the viewpoint of rigidity. Further, from the viewpoint of thinning the transparent conductor 100, the transparent resin substrate 10 is preferably thin. From this point of view, 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, from 1.50 to 1.70 from the viewpoint of producing a transparent conductor excellent in optical characteristics. In addition, the refractive index in this specification is λ = 633 nm, and the temperature is 20 ° C. The value measured under the conditions.

The transparent resin substrate 10 preferably has a high dimensional stability upon heating. In general, a flexible organic resin film produces dimensional changes due to expansion or contraction by heating during film formation. In the uniaxial stretching or the biaxial stretching, the transparent resin substrate 10 having a small thickness can be produced at low cost. When the extraction electrode is formed, when the transparent conductor 100 is heated, dimensional changes occur due to heat shrinkage. Such dimensional change can be measured in accordance with ASTM D1204-02 or JIS-C-2151. The dimensional change rate before and after the heat treatment is determined by setting the size before heating to Lo and the size after heating to L.

Dimensional change rate (%) = 100 × (L-Lo) / Lo

The case where the dimensional change rate (%) is a positive value indicates that expansion is caused by heat treatment, and the case of negative value indicates that shrinkage is caused 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) in the extension. The dimensional change ratio 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 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. The transparent resin substrate may also be a resin film. The transparent conductor 100 can be made excellent in flexibility by using a resin film. Therefore, it is not limited to the transparent conductor used for the touch panel, and can be used for a transparent electrode such as a soft organic EL illumination or an electromagnetic wave shield.

For example, when the transparent conductive body 100 is used as a sensing film constituting a touch panel, the transparent resin substrate 10 may also use a flexible organic resin film to appropriately input externally to a finger, a pen, or the like. Deformation.

The second metal oxide layer 14 is a transparent layer containing an oxide, and contains ZnO as a main component and Ga ₂ O ₃ and GeO ₂ as a subcomponent. The term "main component" as used herein means a component having the highest molar content of the three components of ZnO, Ga ₂ O ₃ and GeO ₂ . The term "subcomponent" means a component other than the above three components. Since the second metal oxide layer 14 contains ZnO as a main component, it is excellent in economic efficiency. Further, the second metal oxide layer 14 having 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 produced without performing thermal annealing treatment.

In the second metal oxide layer 14 , the content of ZnO is, for example, 70 mol% or more, preferably 75 mol% or more, based on the total of the above three components, from the viewpoint of sufficiently improving the transmittance and the conductivity. In the second metal oxide layer 14, the content of ZnO is, for example, 90 mol% or less, preferably 84 mol% or less, based on the total of the above three components. When the ZnO content is too large, it tends to cause white turbidity when stored in a high-temperature and high-humidity environment. On the other hand, when the ZnO content is too small, the transmittance and the conductivity tend to be lowered.

In the second metal oxide layer 14 , the content of Ga ₂ O _{3 is} , for example, 15 mol% or less, preferably 11 mol, from the viewpoint of sufficiently reducing the surface resistance and sufficiently increasing the transmittance. %the following. In the second metal oxide layer 14 , the content of Ga ₂ O _{3 is} , for example, 5 mol% or more, and preferably 8 mol% or more, from the viewpoint of sufficiently improving the storage stability. When the content of Ga ₂ O ₃ is too large, the surface resistance tends to increase and the transmittance tends to decrease. On the other hand, if the Ga ₂ O ₃ content is too small, the preservation of the environment of high temperature and humidity in the case, there will be cloudy and tends to easily generate a high electric resistance of the surface.

In the second metal oxide layer 14 , the content of GeO _{2 is} , for example, 20 mol% or less, preferably 14 mol% or less, from the viewpoint of sufficiently reducing the surface resistance and sufficiently increasing the transmittance. . In the second metal oxide layer 14 , the content of GeO _{2 is} , for example, 5 mol% or more, preferably 8 mol% or more, based on the total of the above three components, from the viewpoint of sufficiently improving the storage stability. When the content of GeO _{2 is} too large, the surface resistance tends to increase and the transmittance tends to decrease. On the other hand, when the content of GeO _{2 is} too small, the surface resistance tends to increase when it is 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 above three components within a range that does not greatly impair the function. However, from the viewpoint of producing the transparent conductor 100 having sufficiently high characteristics, it is preferable that the ratio of the total of the three components in the second metal oxide layer 14 is relatively high. The ratio is, for example, 95 mol% or more, preferably 97 mol% or more. Further, the second metal oxide layer 14 preferably does not contain ITO.

The first metal oxide layer 12 and the second metal oxide layer 14 may be the same or different in thickness, structure, and composition. The description of the composition of the second metal oxide layer 14 can also be directly applied to the first metal oxide layer 12. The first metal oxide layer 12 has the same composition as that of the second metal oxide layer 14, and the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 can be removed at one time by etching. . In addition, transparency and corrosion resistance can be further improved.

The first metal oxide layer 12 may have a different composition from the second metal oxide layer 14. In this case, 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 thickness of the first metal oxide layer 12 and the second metal oxide layer 14 is, for example, 10 to 70 nm from the viewpoint of the thickness suitable for various touch panels.

The first metal oxide layer 12 and the second metal oxide layer 14 can be produced by a vacuum film formation method such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. Among these, a sputtering method is preferred in terms of miniaturization of the film forming chamber and rapid film formation. As the sputtering method, magnetron sputtering is exemplified. As the target, an oxide target, a metal or a semi-metal target can be used.

A wiring electrode or the like may be provided on the second metal oxide layer 14. The current of the metal layer 16 to be described later is conducted from the wiring electrode or the like provided on the second metal oxide layer 14 via the second metal oxide layer 14. Therefore, the second metal oxide layer 14 preferably has high conductivity. On such viewpoint, in the surface of the film 14 of the single resistance value of the second metal oxide layer, for example, it is preferably ^{1.0 × 10 +7 Ω / sq.} (= 1.0E + 7Ω / sq.) Or less, more preferably 5.0 ×10 ⁺⁶ Ω/sq. 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 the group consisting of Pd, Cu, Nd, In, Sn, and Sb. Examples of the silver alloy include Ag-Pd, Ag-Cu, Ag-Pd-Cu, Ag-Nd-Cu, Ag-In-Sn, and Ag-Sn-Sb.

The metal layer 16 may contain additives in addition to the silver alloy. The additive is preferably one which can be easily removed by an etchant. The content of the silver alloy in the metal layer 16 can be, for example, 90% by mass or more, and may be 95% by mass or more. The thickness of the metal layer 16 is, for example, 1 to 30 nm. The thickness of the metal layer 16 is preferably 4 to 11 nm from the viewpoint of sufficiently reducing the surface resistance of the transparent conductor 100 and sufficiently increasing the total light transmittance. 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 be high.

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 formation method such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. Among these, a sputtering method is preferred in terms of miniaturization of the film forming chamber and rapid film formation. As the sputtering method, a DC magnetron sputtering method can be cited. As the target, a metal target can be used.

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

Fig. 2 is a schematic cross-sectional view showing another embodiment of a transparent conductor. Transparent conductive The body 101 is different from the transparent conductor 100 in that a pair of hard coat layers 20 are provided so as to sandwich the transparent resin substrate 10. The other configuration is the same as that of the transparent conductor 100.

In the transparent conductor 101, as the pair of hard coat layers 20, the first hard coat layer 22 is provided on the main surface of the transparent resin substrate 10 on the side of the first metal oxide layer 12, and the transparent resin substrate 10 is bonded to the transparent resin substrate 10. The second hard coat layer 24 is provided on the main surface opposite to the side of the first metal oxide layer 12. In other words, the transparent conductor 101 has 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 in this order. The layered structure of the layer. 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, damage to the transparent resin substrate 10 can be sufficiently suppressed. The hard coat layer 20 contains a cured resin obtained by hardening the resin composition. The resin composition preferably contains at least one selected from the group consisting of a thermosetting resin composition, an ultraviolet curable resin composition, and an electron beam curable resin composition. The thermosetting resin composition may contain at least one selected from the group consisting of an epoxy resin, a phenoxy resin, and a melamine resin.

The resin composition is, for example, a composition containing a curable compound having an energy ray-reactive group such as a (meth) acrylonitrile group or a vinyl group. Further, the expression of the (meth)acryl fluorenyl group means the meaning of at least one of an acryloyl group and a methacryl group. The curable compound is preferably a polyfunctional monomer or oligomer containing two or more, preferably three or more, energy ray-reactive groups in one molecule.

The curable compound preferably contains an acrylic monomer. Specific examples of the acrylic monomer include 1,6-hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, and ethylene oxide-modified bisphenol A di(A). Acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide modified tri(meth)acrylate, trimethylolpropane propylene oxide modified tris(A) Acrylate, pentaerythritol tetra(meth)acrylate, Ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa(meth) acrylate, pentaerythritol tri(meth) acrylate, and 3-(methyl) Acryloxy glycerol mono(meth)acrylate or the like. However, it is not necessarily limited to these compounds. For example, an amine ester-modified acrylate and an ethylene oxide-modified acrylate may also be mentioned.

As the curable compound, a compound having a vinyl group can also 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, and ethylene oxide. Modified hydroquinone divinyl ether, ethylene oxide modified bisphenol A divinyl ether, pentaerythritol trivinyl ether, dipentaerythritol hexavinyl ether, and ditrimethylolpropane polyvinyl ether. However, it is not limited to these.

In the case where the curable compound is cured by ultraviolet rays, the resin composition contains a photopolymerization initiator. As the photopolymerization initiator, various photopolymerization initiators can be used. For example, a known compound such as an acetophenone-based, a benzophenone-based, a benzophenone-based or a thioxanthone can be suitably selected. More specifically, Darocur 1173, Irgacure 651, Irgacure 184, Irgacure 907 (above, trade name, manufactured by Ciba Specialty Chemicals, Japan); and KAYACURE DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) can be cited.

The photopolymerization initiator may be from 0.01 to 20% by mass or from 0.5 to 5% by mass based on the mass of the curable compound. The resin composition may be a known substance in which a photopolymerization initiator is added to the acrylic monomer. The material which added the photopolymerization initiator to the acrylic monomer is, for example, SD-318 (trade name, manufactured by Dainippon Ink and Chemicals Co., Ltd.) and XNR5535 (trade name, long 濑). Manufacturing Co., Ltd.) and so on.

The resin composition may contain organic fine particles and/or inorganic fine particles in order to increase the coating film strength and/or adjust the refractive index and the like. Examples of the organic fine particles include organic fine particles and cross-linking. The acrylic resin fine particles and the crosslinked polystyrene fine particles. Examples of the inorganic fine particles include cerium oxide fine particles, alumina fine particles, zirconia fine particles, titanium oxide fine particles, and iron oxide fine particles. Among these, cerium oxide microparticles are preferred.

The fine particles are also preferably fine particles whose surface is treated with a decane coupling agent, and an energy ray-reactive group such as a (meth) acrylonitrile group and/or a vinyl group exists as a film on the surface. When such reactive fine particles are used, the intensity of the film can be enhanced when the energy ray is irradiated, or the fine particles react with each other, or the fine particles react with the polyfunctional monomer or oligomer. Preferably, the cerium oxide microparticles treated with a (meth)acrylonitrile-based decane coupling agent are used.

From the viewpoint of less than the thickness of the hard coat layer 20 and ensuring sufficient transparency, the average particle diameter of the fine particles may be 100 nm or less, or may be 20 nm or less. On the other hand, from the viewpoint of production of the colloidal solution, it may be 5 nm or more, or may be 10 nm or more. In the case of using the organic fine particles and/or the inorganic fine particles, the total content of the organic fine particles and the inorganic fine particles may be, for example, 5 to 500 parts by mass, or 20 to 200 parts by mass, per 100 parts by mass of the curable compound.

When a resin composition hardened by an energy ray is used, the resin composition can be cured by irradiation with an energy ray such as ultraviolet rays. Therefore, such a resin composition is also preferably used from the viewpoint of the production steps.

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, drying it, and curing the resin composition. The coating at this time can be carried out according to a known method. Examples of the coating method include an extrusion nozzle method, a doctor blade method, a knife method, a bar coating method, a contact coating method, a contact reverse coating method, a gravure coating method, a dipping method, and a reverse roll coating method. , direct roll coating, curtain method and extrusion method. The second hard coat layer 24 can also be produced on the other surface of the transparent resin substrate 10 similarly to 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. When the thickness exceeds 10 μm, thickness unevenness, wrinkles, and the like tend to occur. on the other hand, When the thickness is less than 0.5 μm, when the transparent resin substrate 10 contains a relatively large amount of a low molecular weight component such as a plasticizer or an oligomer, it may be difficult to sufficiently suppress the outflow of the components. Further, from the viewpoint of suppressing warpage, the thicknesses of the first hard coat layer 22 and the second hard coat layer 24 are preferably made the same.

The refractive indices 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 between the refractive indices of 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. By reducing the absolute value of the difference between the refractive indices of the first hard coat layer 22 and the second hard coat layer 24 and the transparent resin substrate 10, the first hard coat layer 22 and the second hard coat layer 24 can be suppressed. The intensity of the interference fringes that occur due to uneven thickness.

The thickness of each layer constituting the transparent conductors 100 and 101 can be measured in the following order. The transparent conductors 100, 101 were cut by a focused ion beam apparatus (FIB, Focused Ion Beam) to obtain a cross section. The cross section was observed using a transmission electron microscope (TEM), and the thickness of each layer was measured. The measurement is preferably carried out at positions of 10 or more arbitrarily selected, and the average value thereof is determined. As a method of obtaining a cross section, a microtome for a microscope can also be used as a device other than the focused ion beam device. As a method of measuring the thickness, a scanning electron microscope (SEM) can also be used. Further, the film thickness can also be measured using a fluorescent X-ray device.

The thickness of the transparent conductors 100 and 101 may be 200 μm or less, or may be 150 μm or less. If it is such a thickness, the required level of thinning can be fully satisfied. The total light transmittance of the transparent conductors 100 and 101 can be made, for example, at a high value of 85% or more. In addition, the surface resistance value (four-terminal method) of the transparent conductors 100 and 101 can be, for example, 30 Ω/sq. or less without performing thermal annealing treatment on the first metal oxide layer 12 and the second metal oxide layer 14. It can also be made 25 Ω/sq. or less.

The transparent conductors 100 and 101 having the above-described configuration have a laminated structure in which the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are laminated. The laminated structure can It is easily removed at one time using a usual etching solution. In addition, it has high transmittance and high conductivity even without thermal annealing. Therefore, it can be suitably used as a sensing film of a touch panel.

3 is a schematic cross-sectional view showing a portion of a cross section of the touch panel 200 having a pair of sensing films. 4(A) and 4(B) are plan views showing the sensing films 100a and 100b of the transparent conductor 100 described above. The touch panel 200 includes a pair of sensing films 100a and 100b disposed opposite each other via the optical glue 18. The touch panel 200 is configured to be capable of calculating the touch position of the contact body as a coordinate position (lateral position and vertical position) in a plane parallel to the two-dimensional coordinate (X-Y coordinate) of the panel 70 to be the screen.

Specifically, the touch panel 200 includes a sensing film 100a for longitudinal position detection (hereinafter referred to as "Y sensing film") and a sensing film 100b for lateral position detection which are bonded via the optical adhesive 18 (hereinafter referred to as It is "X sensing film"). On the lower surface side of the X sensing film 100b, a spacer 92 is provided between the X sensing film 100b and the panel 70 of the display device.

The cover glass 19 is provided via the optical adhesive 17 on the upper surface side (the side opposite to the panel 70 side) of the Y sensor film 100a. In other words, the touch panel 200 has a laminated structure in which the X sensing film 100b, the Y sensing film 100a, and the cover glass 19 are disposed from the panel 70 side in this order on the panel 70.

The Y sensing film 100a for detecting the vertical position and the X sensing film 100b for detecting the lateral position are composed of the transparent conductor 100. The Y sensing film 100a and the X sensing film 100b have a sensor electrode 15a and a sensor electrode 15b as conductive portions so as to face the cover glass 19.

The sensor electrode 15a is composed of a first metal oxide layer 12, a second metal oxide layer 14, and a metal layer 16. As shown in FIG. 4(A), the sensor electrode 15a extends a plurality of roots in the longitudinal direction (y direction) in such a manner as to be able to detect the touch position in the longitudinal direction (y direction). The plurality of root sensor electrodes 15a are arranged in parallel in the longitudinal direction (y direction). One end of the sensor electrode 15a is connected to the electrode 80 on the side of the driving IC via a conductor line 50 formed of a silver paste.

The X sensing film 100b for detecting the lateral position has the sensor electrode 15b on the opposite surface of the Y sensing film 100a. The sensor electrode 15b is composed of a first metal oxide layer 12, a second metal oxide layer 14, and a metal layer 16. As shown in FIG. 4(B), the sensor electrode 15b extends a plurality of roots in the lateral direction (x direction) in such a manner as to be able to detect the lateral (x-direction) touch position. The plurality of root sensor electrodes 15b are arranged in parallel with each other in the lateral direction (x direction). One end of the sensor electrode 15b is connected to the electrode 80 on the side of the driving IC via a conductor line 50 formed of a silver paste.

The Y sensing film 100a and the X sensing film 100b are optically bonded to each other through the sensing film 100a and the X sensing film 100b so that the respective sensor electrodes 15a and 15b are perpendicular to each other. And they are overlapped. On the side opposite to the X sensing film 100b side of the Y sensing film 100a, a cover glass 19 is provided via the optical glue 17. The optical glues 17, 18, the cover glass 19, and the panel 70 can use a usual material.

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

The shape and number of the sensor electrodes 15a and 15b in each of the sensing films 100a and 100b are not limited to those shown in Figs. 3, 4(A) and 4(B). For example, the detection accuracy of the touch position can also be improved by increasing the number of the sensor electrodes 15a, 15b.

The panel 70 is provided via the spacer 92 on the side opposite to the Y sensing film 100a side of the X sensing film 100b. The spacer 92 may be disposed at a position corresponding to the shape of the sensor electrodes 15a, 15b and a position surrounding the entirety of the sensor electrodes 15a, 15b. The spacer 92 may be formed of a light transmissive material such as PET (polyethylene terephthalate) resin. One end of the spacer 92 is attached to the underside of the X sensing film 100b by an optical adhesive or an adhesive such as an acrylic or epoxy-based adhesive. The other end of the spacer 92 is followed by a bonding agent 90 to the panel 70 of the display device. Thus, the X sensing film 100b and the panel 70 are passed through the spacer 92. The opposing direction is such that a gap S can be provided between the X sensing film 100b and the panel 70 of the display device.

The control unit (IC) is electrically connected to the electrode 80. The change in capacity of each of the sensor electrodes 15a and 15b caused by the change in electrostatic capacitance between the fingertip and the Y sensing film 100a of the touch panel 200 is measured. The control unit can calculate the touch position of the contact body as a coordinate position (the intersection of the position in the X-axis direction and the position in the Y-axis direction) based on the measurement result. Further, the method of driving the sensor electrodes and the method of calculating the coordinate position may employ various methods in addition to the above methods.

The touch panel 200 can be manufactured in the following order. After the transparent conductor 100 is prepared, 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 a spin coating method using a photolithography technique. Thereafter, prebaking can be performed in order to improve adhesion. Then, a masking pattern is disposed to perform exposure, and development is performed with a developing solution to form a resist pattern. The formation of the resist pattern is not limited to the photolithography method, and may be formed by a screen printing method or the like.

Then, the transparent conductor 100 forming the resist pattern is immersed in the acidic etching liquid, and the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 at the portions where the resist pattern is not formed are dissolved and removed. Thereafter, the resist layer is removed, thereby obtaining the Y sensing film 100a on which the sensor electrode 15a is formed and the X sensing film 100b on which the sensor electrode 15b is formed.

The first metal oxide layer 12 and the second metal oxide layer 14 are set to have different compositions. When the first metal oxide layer 12 is made of a composition that is not removed by etching, the metal layer 16 can be etched at one time. The second metal oxide layer 14 can also directly retain the first metal oxide layer 12 after etching. As the etching liquid, an inorganic acid-based etching liquid can be used. For example, a phosphate-based etching liquid is preferred.

Then, for example, a metal paste such as a silver alloy paste is applied to form a conductor line 50. And electrode 80. In this manner, the control unit and the sensor electrodes 15a and 15b are electrically connected. Then, the Y-sensing film 100a and the X-sensor film 100b are bonded to each other with the optical glue 18 so that the respective sensor electrodes 15a and 15b are oriented in the same direction. In this case, the sensor electrodes 15a and 15b are bonded to each other in a direction perpendicular to each other when viewed in the lamination direction of the Y sensing film 100a and the X sensing film 100b. Further, the cover glass 19 and the Y sensor film 100a are bonded together using the optical glue 17. The touch panel 200 can be manufactured in this manner.

The touch panel 200 uses the transparent conductor 100 as the Y sensing film 100a and the X sensing film 100b. The transparent conductor 100 can remove the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 by etching at one time. Therefore, the manufacturing process of the touch panel 200 can be simplified, and the touch panel 200 can be easily manufactured.

Further, it is not necessary to use the transparent conductor 100 for both the Y sensing film 100a and the X sensing film 100b, and any other transparent conductor can be used. Even such a touch panel can make the display sufficiently clear. Further, as the sensing film, the transparent conductor 101 may be used without using the transparent conductor 100.

As such, the transparent conductors 100, 101 can be suitably used for a touch panel. However, the use thereof 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 specific shape by etching to form the first metal oxide layer 12. a portion (conductive portion) of the second metal oxide layer 14 and the metal layer 16, and a portion (non-conductive portion) not including the first metal oxide layer 12, the second metal oxide layer 14, and the metal layer 16 It can be used as a transparent electrode, anti-charge, or electromagnetic wave in various display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence panel (organic EL, inorganic EL), electrochromic device, and electronic paper. Broken for use. In addition, 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 embodiments. For example, the transparent conductor 101 has a pair of hard coat layers 20, but may have only one of the first hard coat layer 22 and the second hard coat layer 24. In addition, it can also be transparent A hard coat layer is provided on one surface of the resin substrate 10, and a plurality of optical adjustment layers are provided on the other surface by coating. 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. Further, in the transparent conductors 100 and 101, any layer other than the above layer may be provided at any position within a range that does not greatly impair the function.

[Examples]

The present invention will be further specifically described by the following examples and comparative examples, but the invention is not limited to the examples.

[Examples 1 to 18]

(Production 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 substrate 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. The transparent conductors of the respective examples were fabricated as described below.

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. The first metal oxide layer, the metal layer, and the second metal oxide layer are sequentially formed by DC magnetron sputtering on the transparent resin substrate. 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 of the examples were formed using targets having the same composition. The composition of the first metal oxide layer and the second metal oxide layer in each of the examples is shown in Table 1. The thickness of the first metal oxide layer and the second metal oxide layer in each of the examples was 50 nm.

In all of the examples shown in Table 1, the metal layer was formed using an AgPdCu (Ag: Pd: Cu = 99.0: 0.5: 0.5 (% by mass)) target. The thickness of the metal layer 16 was made 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, or nitric acid is prepared. The transparent conductor of each example was immersed in the etching solution for 1 minute at room temperature to perform etching. Thereafter, the total light transmittance was measured, and it was determined whether or not the first metal oxide layer, the metal layer, and the second metal oxide layer were dissolved. Specifically, the case where the total light transmittance of the sample after etching coincides with the total light transmittance of only the transparent resin substrate is judged as "A", and the case where the film does not match is determined as "B". The total light transmittance (transmittance) was measured using a turbidity meter (trade name: NDH-7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The evaluation results are shown in Table 1.

The surface resistance of each of the examples was measured using a four-terminal resistivity meter (trade name: manufactured by Loresta GP Mitsubishi Chemical Corporation). The measurement results are shown in Table 1. In Table 1, "surface resistance (1)" is a surface resistance value of a transparent conductor stored in an environment of 85 ° C and 85% RH (rel. 85% relative humidity) for 50 hours. "Surface resistance (2)" The surface resistance value after storage under the above environmental conditions.

After the transparent conductors of the respective examples were stored in an environment of 85 ° C and 85% RH, the storage stability was evaluated visually. The case where white turbidity was observed in the transparent conductor was judged as "B", and the case where white turbidity was not observed was judged as "A". The judgment results are shown in Table 1.

As shown in Table 1, the evaluation of the etching characteristics was "A" in all the examples. 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. In addition, the surface resistance after storage in a high temperature and high humidity environment is also high. This is because the conductivity of the second metal oxide layer in contact with the four terminals of the surface resistance measuring device is lowered. Therefore, in the application in which the wiring electrode is not required to be electrically connected to the second metal oxide layer, even if the surface resistance (2) is high, it does not become a practical problem. Further, the storage stability is a level that can be sufficiently used if it is not required to have such a high level of transparency, for example, a noise sheet or the like (for example, noise interruption).

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

As shown in Table 1, it was confirmed that the absorption rate of the metal oxide layer of each of the examples was sufficiently low. Further, it was confirmed that even if ZnO is contained as a main component, corrosion resistance can be improved by containing Ga ₂ O ₃ and GeO ₂ as subcomponents.

[Examples 19 to 30]

A transparent conductor was produced in the same manner as in Example 6 except that the target composition at the time of producing the metal layer was changed, and the composition of the metal layer was changed and/or the thickness of the metal layer was changed as shown in Table 3. That is, the thickness of the metal layer was changed in Examples 19 to 26. A target layer of AgNdCu (Ag: Nd: Cu = 99.0: 0.5: 0.5 (% by mass)) was used in Example 27 to form a metal layer. A AgInSn (Ag:In:Sn=99.0:0.5:0.5 (% by mass)) target was used in Example 28 to form a metal layer. AgSnSb (Ag:Sn:Sb=99.0:0.5:0.5 (% by mass)) target was used in Example 29. To form a metal layer. An AgCu (Ag: Cu = 99.5: 0.5 (% by mass)) target was used in Example 30 to form a metal layer.

The transparent conductors of Examples 19 to 30 produced were evaluated in the same manner as in Example 6. The evaluation results are shown in Table 3. Further, the compositions and thicknesses of the metal oxide layers of Examples 19 to 30 were the same as in Example 6. In addition, the storage stability was measured under the conditions of storage in an environment of 85 ° C and 85% RH for 50 hours and storage in an environment of 60 ° C and 90% RH for 50 hours. After storage under various conditions, the case where white turbidity was observed in the transparent conductor was visually determined as "B", and the case where white turbidity was not observed was judged as "A".

According to the results shown in Table 3, the evaluation of the etching characteristics in all the examples was "A". 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. Further, it has been confirmed that when the thickness of the metal layer is increased, the surface resistance tends to be small and the total light transmittance tends to decrease. In addition, it was confirmed that the case where the silver alloy contains Pd is particularly excellent in storage stability.

[Comparative Examples 1 to 4]

A transparent conductor of Comparative Examples 1 to 4 was produced in the same manner as in Example 1 except that the target having the composition shown in Table 4 was used as the target for forming the first metal oxide layer and the second metal oxide layer. In Comparative Example 1, a first metal oxide layer and a 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. In Comparative Example 4, a ZnO-SnO ₂ -Cr ₂ O ₃ target was used. In each of the comparative examples, the first metal oxide layer and the second metal oxide layer were formed using targets having the same composition. The composition of the first metal oxide layer and the second metal oxide layer in each of the comparative examples is shown in Table 4. The etching characteristics of the transparent conductors of the respective comparative examples were evaluated in the same manner as in the first embodiment. The results are shown in Table 4.

As shown in Table 4, it was confirmed that the transparent conductor having the metal oxide layer containing no three components of ZnO-Ga ₂ O ₃ -GeO ₂ could not be sufficiently etched.

10‧‧‧Transparent resin substrate

12‧‧‧1st metal oxide layer

14‧‧‧2nd metal oxide layer

16‧‧‧metal layer

100‧‧‧Transparent conductor

Claims (10)

A transparent conductor in which 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, and the second metal oxide layer contains ZnO as a main component and contains Ga ₂ O ₃ and GeO ₂ as a sub-component, the second metal oxide layer is ZnO, the total of the three components of Example ₂ Ga ₂ O ₃ and GeO less than 95mol%. The transparent conductor of claim 1, wherein the content of the ZnO is 70 to 90 mol% with respect to the total of the three components of the ZnO, Ga ₂ O ₃ and GeO ₂ in the second metal oxide layer. In total, the content of Ga ₂ O ₃ is 5 to 15 mol%, and the content of GeO ₂ is 5 to 20 mol% based on the total of the above three components. The transparent conductor of claim 1 or 2, wherein the metal layer has a thickness of 4 to 11 nm. The transparent conductor according to claim 1 or 2, wherein the first metal oxide layer contains ZnO as a main component and contains Ga ₂ O ₃ and GeO ₂ as a subcomponent. The transparent conductor of claim 3, wherein the first metal oxide layer contains ZnO as a main component and contains Ga ₂ O ₃ and GeO ₂ as an auxiliary component. The transparent conductor of claim 1 or 2, 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. The transparent conductor of claim 3, 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. The transparent conductor of claim 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. The transparent conductor of claim 5, wherein the silver alloy is Ag and selected from the group consisting of Pd and Cu. An alloy of at least one of Nd, In, Sn, and Sb. A touch panel is provided with a sensing film on a panel, and the sensing film is composed of a transparent conductor according to any one of claims 1 to 9.