JP6048529B2 - Transparent conductive film and touch panel - Google Patents

Description

  The present invention relates to a transparent conductive film and a touch panel using the transparent conductive film.

  ITO (indium tin oxide) is widely used as a transparent conductive film. In recent years, in order to improve the sensitivity and increase the area of the touch panel, for example, 50Ω / sq. A transparent conductive film having the following low surface resistance is required.

  However, the surface resistance of the ITO film having a film thickness of about 20 nm is 100 Ω / sq. The above-mentioned requirement cannot be satisfied. For this reason, the movement of replacing ITO is accelerating. There is a sandwich type transparent conductive film that can realize a low resistance that surpasses the ITO film (see, for example, Patent Documents 1 and 2). This type of transparent conductive film achieves both low resistance and high transmittance by sandwiching a metal thin film between metal oxide thin films.

  A metal oxide thin film used for a sandwich type transparent conductive film based on zinc oxide (ZnO) has been proposed. By adjusting the types and contents of various oxides that are components other than the main material ZnO, in addition to high transmittance, sufficiently low surface resistance and sufficient environmental resistance can be imparted. it can.

  However, in the spectral transmittance shown in FIG. 2 of Patent Document 1, the transmittance is reduced at short wavelengths and long wavelengths. Since the sandwich-type transparent conductive film uses the interference effect, a wavelength having a high transmittance and a wavelength having a low transmittance are mixed. As a result, the color tone of the transmitted light changes, and the color reproducibility deteriorates in applications such as displays.

  In order to suppress such a change in color tone, in Patent Document 2, in a transparent conductive film having a laminated structure of a metal thin film and a metal oxide thin film, a dye which is a complementary color of the transparent conductive film is contained in the transparent substrate. In other words, the color tone correction of the transmitted color is realized by coating on the surface of the transparent substrate. However, in the configuration of Patent Document 2, since the color tone of the transmitted color is adjusted by absorbing light of a specific wavelength using a dye, the transmittance of the entire film is lowered. It is difficult to increase the transmittance by the technique described in Patent Document 2.

  When the transparent conductive film is incorporated into a device such as a touch panel, for example, the lead wiring is often connected to the transparent conductive film. At that time, in order to improve the conduction between the lead-out wiring and the transparent conductive film, the metal oxide thin film needs to exhibit a stable resistance value on the surface thereof.

  Conventionally, many glass substrates are used as a transparent substrate. However, when the area is increased, the weight is increased, and the glass is easily broken when dropped. Therefore, it is advantageous to apply a light resin film that is hard to break as a transparent substrate. When such a thin resin film is applied, the probability that an increase in surface resistance value, an increase in haze, and a decrease in transmittance will increase when the resin film is bent. Therefore, in order to realize a large area of the transparent conductive film, it is necessary to simultaneously realize a high flexibility that does not cause a change in characteristics even when bent. In addition to this, the resin film is likely to swell due to the environment such as humidity as compared with glass or the like, and there is a concern that the resistance value and color tone of the transparent conductive film formed thereon deteriorate over time. Therefore, it is necessary to have a barrier performance that prevents permeation of environmental substances such as moisture.

Japanese Patent Laid-Open No. 09-176837 JP 2000-147244 A

  In one aspect, an object of the present invention is to provide a transparent conductive film that exhibits a stable resistance value on the outermost surface and has high flexibility and high environmental resistance. Moreover, this invention makes it a subject to provide the touch panel which is excellent in the above-mentioned characteristic by using the said transparent conductive film in another side surface.

  In order to solve such problems, the present inventors have intensively studied. As a result, in a transparent conductive film in which a transparent conductive film having a three-layer structure in which a metal thin film is sandwiched between metal oxide thin films is formed on a transparent substrate, the oxide is so formed that the refractive index of the metal oxide thin film is increased. An attempt was made to adjust the composition ratio of the materials to a predetermined range. As a result, it has been found that a highly practical transparent conductive film having a stable resistance value on the outermost surface of the metal oxide thin film and having both high flexibility and high environmental resistance can be obtained. Furthermore, by forming the metal oxide thin film within a predetermined film thickness range, the metal thin film can be, for example, 50 Ω / sq. It has been found that even when the thickness is equal to or greater than a predetermined thickness required for obtaining the following surface resistance, the wavelength dependency of the transmittance is small and a high transmittance can be obtained. Further, it has been found that low resistance and high color reproducibility are realized.

  Furthermore, the present inventors have found that a touch panel with extremely high color reproducibility can be obtained by using this transparent conductive film. In this way, the present invention has been completed.

  That is, in one aspect, the present invention is a transparent conductive film comprising a transparent substrate and a transparent conductive film on the transparent substrate, the transparent conductive film sandwiching the metal thin film and the metal thin film. The metal element contained in the pair of metal oxide thin films is mainly Ti, Nb or Sn, and Zn, and Ti, Nb or Sn, and Zn Each content rate of provides a transparent conductive film which is 10-80 mol% on the basis of these sum totals.

  Such a transparent conductive film has a very high practicality because it exhibits a stable resistance value on the outermost surface and has both high flexibility and high environmental resistance.

  When the metal element contained in the pair of metal oxide thin films is mainly Ti, Nb and Zn, among the pair of metal oxide thin films, the Ti content is X, the Nb content is Y, and Zn. When the content rate is Z, a smaller value of 26X + 23Y + 21Z may have a larger film thickness. Thereby, in addition to the above characteristics, the color reproducibility can be sufficiently improved by the balance of the refractive index.

  When the metal element contained in the pair of metal oxide thin films is mainly Ti, Sn, and Zn, among the pair of metal oxide thin films, the Ti content is X, the Sn content is W, and Zn. When the content is Z, the smaller value of 26X + 19W + 21Z may have a larger film thickness. Thereby, in addition to the above characteristics, the color reproducibility can be sufficiently improved by the balance of the refractive index.

  The film thickness of the metal thin film may be 5 to 11 nm. The thickness of the pair of metal oxide thin films may be 20 to 50 nm, respectively. By adopting such a structure, in addition to the above characteristics, the initial surface resistance can be sufficiently lowered and the color reproducibility can be further improved.

  In another aspect, the present invention provides a touch panel including the above-described transparent conductive film. Since this touch panel includes the above-described transparent conductive film, it has excellent characteristics and durability.

  The transparent conductive film of the present invention has resistance equivalent to the transparent conductive film on which the ITO film is formed while having the same transmittance as that of the transparent conductive film on which the ITO film is formed. Can be realized. Further, when a transparent substrate of a thin resin film is used, a high flexibility that does not cause cracks even when bent can be realized. In addition, deterioration of characteristics over time due to the influence of humidity and the like can be sufficiently suppressed. Therefore, high performance can be maintained over a long period of time. In addition, since it is possible to achieve high color reproducibility that hardly impairs the color tone of the transmitted color, it is suitable for applications such as touch panels that require light weight and flexibility.

  The transparent conductive film of the present invention can be applied as a transparent electrode for a liquid crystal display, an electroluminescence display, a solar cell panel, etc. in addition to a touch panel. It can also be applied to uses such as heat ray shielding, electromagnetic wave shielding, and transparent heating elements.

It is a schematic cross section which shows the basic structure of the transparent conductive film which concerns on the 1st Embodiment of this invention. It is a schematic cross section which shows the modification of the transparent conductive film of FIG. It is a schematic cross section which shows another modification of the transparent conductive film of FIG. It is a schematic cross section which shows the structure of the transparent conductive film which concerns on the 2nd Embodiment of this invention. It is a schematic cross section which shows the structure of the transparent conductive film which concerns on the 3rd Embodiment of this invention. It is a schematic cross section of the transparent conductive film in which the pattern based on the 4th Embodiment of this invention was formed. It is a schematic cross section which shows one Embodiment of the touchscreen of this invention. It is a schematic cross section which shows another embodiment of the touchscreen of this invention. It is a figure which shows one example of the matrix shape of the touchscreen produced using the transparent conductive film of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted in some cases. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic cross-sectional view of a transparent conductive film according to the first embodiment. The transparent conductive film 10a of FIG. 1 includes a transparent conductive film 60 on one surface (one main surface) of the transparent substrate 12. The transparent conductive film 60 includes a metal thin film 16 and a pair of metal oxide thin films 15 and 18 sandwiching the metal thin film 16. That is, the transparent conductive film 60 has a three-layer structure in which the first metal oxide thin film 15, the metal thin film 16, and the second metal oxide thin film 18 are laminated in this order from the transparent substrate 12 side. . The first metal oxide thin film 15 and the second metal oxide thin film 18 (hereinafter sometimes collectively referred to as “metal oxide thin films 15 and 18”) are formed with the same film thickness. The composition of the first metal oxide thin film 15 and the second metal oxide thin film 18 may be the same or different from each other.

  FIG. 2 is a schematic cross-sectional view of a transparent conductive film 10b that is a modification of the first embodiment. The transparent conductive film 10b of FIG. 2 differs from the transparent conductive film 10a of FIG. 1 in that a functional resin layer 13 is provided between the transparent substrate 12 and the first metal oxide thin film 15. That is, the transparent conductive film 10 b has the functional resin layer 13 between the transparent substrate 12 and the transparent conductive film 60. The functional resin layer 13 has an action of improving the hardness or strength of the transparent substrate 12. The functional resin layer 13 includes, for example, a resin composition containing a curable compound having an energy ray reactive group such as a (meth) acryloyl group or a vinyl group.

  The curable compound contains, for example, 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.

  The curable compound contains, for example, a compound having a vinyl group. Specific 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, and ethylene oxide-modified bisphenol A. Examples thereof include divinyl ether, 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 BASF Japan Ltd.), and KAYACURE DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) can be mentioned.

  What is necessary is just to mix | blend a photoinitiator in the ratio of about 0.01-20 mass% or 0.5-5 mass% with respect to a sclerosing | hardenable compound. The resin composition may be a known composition in which a photopolymerization initiator is blended with an acrylic monomer. As what mix | blended the photoinitiator with the acryl-type monomer, SD-318 (brand name, the product made by DIC Corporation) which is ultraviolet curable resin, XNR5535 (brand name, the product made by Nagase Sangyo Co., Ltd.) etc., for example Is mentioned.

  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 functional resin layer 13 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 functional resin layer 13 can be produced by applying a solution or dispersion of the resin composition onto one surface of the transparent substrate 12 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 thickness of the functional resin layer 13 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 11 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.

  FIG. 3 is a schematic cross-sectional view of a transparent conductive film 10c which is another modified example of the first embodiment. The transparent conductive film 10c of FIG. 3 is different from the transparent conductive film 10b of FIG. 2 in that an adhesion layer 14 is further provided between the functional resin layer 13 and the first metal oxide thin film 15. Different. That is, the transparent conductive film 10 c has the functional resin layer 13 and the adhesion layer 14 in this order from the transparent substrate 12 side between the transparent substrate 12 and the transparent conductive film 60. The adhesion layer 14 has an effect of improving the adhesion between the functional resin layer 13 and the first metal oxide thin film 15.

  FIG. 4 is a schematic cross-sectional view of a transparent conductive film 20a according to the second embodiment. The transparent conductive film 20a of FIG. 4 includes a transparent conductive film 60a on one surface of the transparent substrate 12. The transparent conductive film 60a has a three-layer structure in which the first metal oxide thin film 15, the metal thin film 16, and the second metal oxide thin film 18a are laminated in this order from the transparent substrate 12 side. The first metal oxide thin film 15 is formed thicker than the second metal oxide thin film 18a. Thus, the film thicknesses of the first metal oxide thin film 15 and the second metal oxide thin film 18a may be different from each other.

  FIG. 5 is a schematic cross-sectional view of a transparent conductive film 20b according to the third embodiment. The transparent conductive film 20 b includes a transparent conductive film 60 b on one surface of the transparent substrate 12. The transparent conductive film 60b has a three-layer structure in which the first metal oxide thin film 15a, the metal thin film 16, and the second metal oxide thin film 18 are laminated in this order from the transparent substrate 12 side. The first metal oxide thin film 15 a is formed thinner than the second metal oxide thin film 18.

  FIG. 6 is a schematic cross-sectional view of a transparent conductive film 30 according to the fourth embodiment. A pattern may be formed on the transparent conductive film 30 as shown in FIG. The transparent conductive film 30 includes a transparent conductive portion 32 and an insulating portion made of a transparent conductive film 60 in which a first metal oxide thin film 15, a metal thin film 16, and a second metal oxide thin film 18 are laminated in this order. 34 is formed. That is, the transparent conductive film 60 exists in the transparent conductive part 32, whereas the transparent conductive film 60 does not exist in the insulating part 34. The transparent conductive film 30 can be obtained, for example, by etching a part of the transparent conductive film 60 in the transparent conductive film 10a of FIG.

  “Transparent” in the present specification means that visible light is transmitted, and the light may be scattered to some extent. About the degree of light scattering, the level requested | required changes with the uses of a transparent conductive film. 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.

As shown in FIGS. 1-6, the transparent conductive film 10a (10b, 10c, 20a, 20b, 30) , Hand metal thin film 16 (silver-based thin film) on the metal oxide thin film 15 and 18 (18 a) A sandwiched transparent conductive film 60 (60a, 60b) having a three-layer structure is formed on at least one surface of the transparent substrate 12. The metal elements contained in the metal oxide thin films 15, 18 (18a ) are mainly Ti and Nb and Zn, or Ti, Sn and Zn, and the content of each metal element is 10 mol% or more and 80 mol%. It is as follows. Two metal oxide thin films 15 and 18 (18a ) may be formed on both sides of the metal thin film 16. The film thickness of the metal thin film 16 is 5 nm or more and 11 nm or less, for example. The film thickness of the metal oxide thin films 15 and 18 (18a ) is, for example, not less than 20 nm and not more than 50 nm. The material and shape of each member of each transparent conductive film shown in FIGS.

<Transparent substrate>
As the transparent substrate 12, an inorganic compound molded product such as soda lime glass, non-alkali glass, or quartz glass can be used. From the viewpoint of being light and difficult to break, a polymer molded product can be used more suitably. The polymer molding may be transparent in the visible wavelength region. Examples of the polymer include polyethylene terephthalate, polyether sulfone, polystyrene, polyethylene naphthalate, polyarylate, polyether ether ketone, polycarbonate, polyethylene, polypropylene, nylon 6 and other cellulose, polyimide, triacetyl cellulose, and other cellulose-based polymers. Resin, polyurethane, fluorine-based resin such as polytetrafluoroethylene, vinyl compound such as polyvinyl chloride, polyacrylic acid, polyacrylic acid ester, polyacrylonitrile, addition polymer of vinyl compound, polymethacrylic acid, polymethacrylic acid ester, Copolymerization of vinylidene compounds such as polyvinylidene chloride, vinyl compounds such as vinylidene fluoride / trifluoroethylene copolymer, ethylene / vinyl acetate copolymer, or fluorine compounds Body, polyethers such as polyethylene oxide, epoxy resins, polyvinyl alcohol, and polyvinyl butyral. However, the polymer is not limited to these. One of the above may be used alone, or two or more may be used in combination.

  The transparent polymer molding may be plate-shaped or film-shaped as long as the main surface is smooth. A film-like material rich in flexibility can be used particularly preferably. The thickness of the transparent substrate 12 is not particularly limited. For example, in the case of a polymer molded product, the thickness is 25 to 200 μm, preferably 50 to 188 μm. If it is an inorganic compound molding, it is 0.1-1 mm, Preferably it is 0.3-0.7 mm. If the thickness of the transparent substrate 12 is too thin, handling tends to be difficult. On the other hand, if it is too thick, the transparent substrate 12 tends to be heavy and at the same time the cost is increased.

  As shown in FIG. 2, a functional resin layer 13 having an effect of improving the hardness or strength of the transparent substrate 12 may be formed on the surface of the transparent substrate 12. As shown in FIG. 3, an adhesion layer 14 having a function of improving adhesion between the functional resin layer 13 and the first metal oxide thin film 15 may be further formed. The materials, film thicknesses, and the like of the functional resin layer 13 and the adhesion layer 14 can be appropriately adjusted according to the function.

<Metal oxide thin film>
The metal oxide thin films 15 and 18 contain one of Ti, Nb, and Sn, and Zn as main metal elements. When Nb is contained as a main metal element, the content of each metal element is 10 to 80 mol% based on the total of Ti, Nb, and Zn. When Sn is contained as the main metal element, the content of each metal element is 10 to 80 mol% based on the total of Ti, Sn, and Zn. By setting it as such a composition range, it can be set as the transparent conductive film which is excellent in stability of surface resistance, environmental resistance, and flexibility.

The metal oxide thin films 15 and 18 contain titanium oxide, niobium oxide or tin oxide, and zinc oxide. Titanium oxide is, for example, TiO _2. Niobium oxide is, for example, Nb ₂ O ₅ . Tin oxide is, for example, SnO _2. Zinc oxide is, for example, ZnO. The ratio of metal atoms to oxygen atoms in each metal oxide may deviate from the stoichiometric ratio. The content of each metal element can be determined by, for example, fluorescent X-ray analysis.

  The thickness of the metal oxide thin film is preferably 20 to 50 nm. If the thickness of the metal oxide thin film is less than 20 nm or greater than 50 nm, the optical interference effect for converting the reflected light generated by the metal thin film into transmitted light may deviate from the optimum conditions. is there. For this reason, the color tone change of the transmitted light cannot be suppressed, and the color reproducibility may be deteriorated.

  The thickness of each layer constituting the transparent conductive film 10a (10b, 10c, 20a, 20b, 30) can be measured by the following procedure. The transparent conductive film is 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.

  When the Ti content based on the sum of Ti, Nb or Sn, and Zn is less than 10 mol%, the barrier properties against environmental substances such as moisture that are about to be obtained by addition of Ti are reduced, and the resistance value and The transmittance will deteriorate over time. Ti also has the effect of increasing the refractive index of the oxide thin film. Therefore, if the Ti content is low, the refractive index of the oxide thin film cannot be increased. For this reason, when the film thickness of a metal thin film is large, the color tone change of the transmitted light cannot be suppressed, and color reproducibility will deteriorate. On the other hand, when the content of Ti exceeds 80 mol%, the content of any of Nb, Sn, or Zn is less than 10 mol% as described later, and the effect that is originally intended to be obtained with these elements is obtained. It can no longer be obtained.

  When the content of Nb or Sn is less than 10 mol%, based on the sum of Ti, Nb or Sn, and Zn, the metal oxide thin film is made amorphous by adding Nb or Sn, and cracks when bent The effect of suppressing the generation is weakened, and the bending resistance is lowered. On the other hand, when the content of Nb or Sn exceeds 80 mol%, the content of either Ti or Zn described below is less than 10 mol%, and the effect originally intended to be obtained with these elements is obtained. It can no longer be obtained.

  When the Zn content based on the sum of Ti, Nb or Sn, and Zn is less than 10 mol%, the effect of imparting conductivity to the film by adding Zn and having a stable resistance value on the outermost surface is weakened. End up. As a result, connection failure with the lead wiring when used as a device occurs. Moreover, when the said content rate of Zn exceeds 80 mol%, content of either the above-mentioned Ti, or Nb, or Sn will be less than 10 mol%, and the effect which is originally going to be obtained with these elements is acquired. It will not be possible.

  When the metal oxide thin films 15 and 18 contain Ti, Nb, and Zn as main metal elements, and the compositions of the first metal oxide thin film 15 and the second metal oxide thin film 18 are different, FIG. As shown in FIG. 5, each thin film may be formed with a different film thickness so that the color tone change of the transmitted color is minimized. Specifically, among the metal oxide thin films 15 and 18, it is preferable to make the film thickness of the smaller value represented by 26X + 23Y + 21Z thicker than the film thickness of the larger value. This parameter correlates with the refractive index of the metal oxide thin films 15 and 18 containing Ti, Nb, and Zn as main metal elements. Using this parameter, the magnitude relationship between the refractive indexes of the metal oxide thin films 15 and 18 can be determined.

  X, Y, and Z in the above formulas are the content percentages of Ti, Nb, and Zn on the basis of the total of Ti, Nb, and Zn, respectively. Each coefficient multiplied by X, Y, and Z in the above formula is a numerical value corresponding to the refractive index of each oxide mainly constituting the metal oxide thin films 15 and 18. Specifically, the refractive index of each oxide simple substance is multiplied by 10, and the first decimal place is rounded off.

  When the metal oxide thin films 15 and 18 contain Ti, Sn, and Zn as main metal elements and the compositions of the first metal oxide thin film 15 and the second metal oxide thin film 18 are different, FIG. As shown in FIG. 5, each thin film may be formed with a different film thickness so that the color tone change of the transmitted color is minimized. Specifically, among the metal oxide thin films 15 and 18, it is preferable to make the film thickness of the smaller value represented by 26X + 19W + 21Z thicker than the film thickness of the larger value. This parameter has a correlation with the refractive index of the metal oxide thin films 15 and 18 containing Ti, Sn, and Zn as the main metal elements, and the magnitude relationship between the refractive indexes of the metal oxide thin films 15 and 18 is determined using this parameter. can do.

  X, W, and Z in the above formulas are molar contents of Ti, Sn, and Zn, respectively, based on the sum of Ti, Sn, and Zn. Each coefficient multiplied by X, Y, and Z in the above formula is a numerical value corresponding to the refractive index of each oxide mainly constituting the metal oxide thin films 15 and 18. Specifically, the refractive index of each oxide simple substance is multiplied by 10, and the first decimal place is rounded off.

  Examples of the method for forming the metal oxide thin films 15 and 18 include DC magnetron sputtering using an oxide target having each metal element as a constituent element. The film forming method is not limited to this, and other vacuum film forming methods using plasma or ion beam, or a coating method using a liquid in which constituent elements are dispersed in an appropriate binder can be appropriately selected.

  The metal element contained in the metal oxide thin films 15 and 18 only needs to be mainly composed of one of the combinations shown above, that is, a combination of Ti, Nb, and Zn, or a combination of Ti, Sn, and Zn. Other trace amounts of metal elements may be included. For example, a desired effect can be obtained even if a trace amount of metal element includes Al, Mg, Th, Y, Hf, La, Si, Nd, Sb, In, Zr, Ta, Ce, W, Bi, or the like. be able to. These metal elements may be included as oxides. The total content of Ti, Nb or Sn, and Zn with respect to all metal elements may be, for example, 95 mol% or more, or 98 mol% or more.

<Metal thin film>
The metal thin film 16 of the present invention is preferably mainly composed of silver having a low volume resistivity. The film thickness is preferably 5 to 11 nm (5 nm to 11 nm). When the metal thin film 16 is less than 5 nm, 50Ω / sq. The following surface resistance tends to be difficult to obtain. On the other hand, when the film thickness exceeds 11 nm, the increase in the refractive index of the metal oxide thin films 15 and 18 reaches the limit, the color tone change of the transmitted light cannot be suppressed, and the color reproducibility tends to be lowered. The metal thin film 16 can be formed using, for example, DC magnetron sputtering. The film forming method of the metal thin film 16 is not particularly limited, and other vacuum film forming methods using plasma or ion beam, or a coating method using a liquid in which constituent elements are dispersed in an appropriate binder can be appropriately selected. is there.

  The material of the metal thin film 16 only needs to be mainly silver, and may contain other trace amounts of metal elements. For example, when a trace amount of Cu, Nd, Pt, Pd, Bi, Sn, Sb, etc. is contained, the environmental resistance of silver is improved. Silver and these trace metals may be alloyed. Examples of silver alloys include Ag-Pd, Ag-Cu, Ag-Pd-Cu, Ag-Nd-Cu, Ag-In-Sn, and Ag-Sn-Sb.

<Touch panel>
Next, an embodiment of the touch panel of the present invention will be described. The touch panel of this embodiment has one of the transparent conductive films described above. Here, as an example, the case where the above-described transparent conductive film is applied to a capacitive touch panel will be described. The structure of the capacitive touch panel is usually such that a first pattern (for example, the pattern 52 in FIG. 9) and a second pattern (for example, the pattern 54 in FIG. 9) made of a matrix-like transparent conductive film are formed on a transparent substrate. ).

  FIG. 7 shows a cross-sectional structure in an embodiment of a touch panel manufactured using two transparent conductive films each having a pattern. FIG. 8 shows a cross-sectional structure of another embodiment of a touch panel manufactured using two transparent conductive films each having a pattern formed thereon. As a transparent conductive film used for production of a touch panel as shown in FIGS. 7 and 8, for example, a transparent conductive film having a pattern as shown in FIG. 6 can be used.

  The touch panel 40a shown in FIG. 7 includes a surface on the second metal oxide thin film 18 side of the first transparent conductive film 44 on which the pattern is formed, and a transparent substrate on the second transparent conductive film 46 on which the pattern is formed. 12 'is bonded together by the transparent adhesive layer 42. The transparent conductive film 60 in the first transparent conductive film 44 constitutes the X transparent wiring 52. The transparent conductive film 60 ′ in the second transparent conductive film 46 constitutes the Y transparent wiring 54. The transparent conductive film 60 has a three-layer structure in which the first metal oxide thin film 15, the metal thin film 16, and the second metal oxide thin film 18 are laminated in this order from the transparent substrate 12 side. The transparent conductive film 60 ′ has a three-layer structure in which a first metal oxide thin film 15 ′, a metal thin film 16 ′, and a second metal oxide thin film 18 ′ are laminated in this order from the transparent substrate 12 ′ side. Have

  The touch panel 40b in FIG. 8 includes a surface of the first transparent conductive film 44 on which the pattern is formed on the second metal oxide thin film 18 side and a second of the second transparent conductive film 46 on which the pattern is formed. The surface of the metal oxide thin film 18 ′ is bonded with the transparent adhesive layer 42. The transparent conductive film 60 in the first transparent conductive film 44 constitutes an X transparent wiring. The transparent conductive film 60 ′ in the second transparent conductive film 46 constitutes a Y transparent wiring.

  The stacking order of the X transparent wiring and the Y transparent wiring is not limited to the order described here. Moreover, the material of the transparent adhesive layer 42 is not particularly limited, and any resin material having excellent permeability and adhesiveness can be selected as appropriate. Although not shown, a protective panel that is in direct contact with the finger is disposed on one of the upper and lower surfaces of FIGS. 7 and 8, and a display panel such as a liquid crystal or organic EL is disposed on the other surface. May be. The protective panel and the display panel are bonded to each other by a suitably selected transparent adhesive or the like.

  The lead-out wiring 48 is connected to the X transparent wiring (transparent conductive film 60) and the Y transparent wiring (transparent conductive film 60 ') in the touch panel of FIGS. The lead wiring connected to the Y transparent wiring is not shown. The material of the lead wiring 48 is particularly limited. In general, a material having a low volume resistivity is preferable. For example, Cu, Ag, or the like can be suitably used.

  FIG. 9 is a diagram illustrating an example of a matrix shape of the touch panel. Such a touch panel can be manufactured using any of the above-described transparent conductive films. In the touch panel 50 in FIG. 9, a pattern 52 in which conductive regions having a rhombus shape are bridge-connected in the X direction and a pattern 54 in which conductive regions having a rhombus shape are bridge-connected in the Y direction fill a gap. Are arranged as follows.

  A pattern 52 in FIG. 9 is an X transparent wiring, and is constituted by the transparent conductive film 60 in the first transparent conductive film 44 in FIG. A pattern 54 in FIG. 9 is a Y transparent wiring, and is composed of the transparent conductive film 60 ′ in the second transparent conductive film 46 in FIG. 8.

  A lead wiring 58 is connected to the X transparent wiring (pattern 52) and the Y transparent wiring (pattern 54) in FIG. The lead wiring 58 corresponds to the lead wiring 48 of FIG.

  Although the electrostatic capacity method can be further classified into several methods, the operation principle of the self-capacitance touch panel will be described based on the touch panel structure shown in FIGS.

  In the self-capacitance type touch panel, a current is alternately passed (scanned) through the X transparent wiring and the Y transparent wiring shown in FIGS. 8 and 9, and the capacitance value is read. As the finger approaches, a capacitor is formed between the nearby pattern portion and the finger, and the capacitance changes. The X transparent wiring and the Y transparent wiring respectively detect where the capacitance has changed, so that it is possible to determine where the finger is located.

  Another method is a mutual capacitance method. This is a method of reading a change in capacitance value formed between the X transparent wiring and the Y transparent wiring, unlike the self-capacitance method that detects a capacitance change between the conductive pattern and the finger. That is, a capacitor is formed between the X transparent wiring and the Y transparent wiring. When a finger approaches the capacitor, the electric field distribution formed between the X transparent wiring and the Y transparent wiring changes, and the X transparent wiring is changed. The capacitance value between the wiring and the Y transparent wiring changes. By detecting this, it is determined at which position the finger is located. This method has an advantage of higher sensitivity to multipoint contact than the self-capacitance method.

  In both the self-capacitance method and the mutual capacitance method, a current is alternately passed through the X transparent wiring and the Y transparent wiring to detect the touch position. Usually, the detection accuracy of the touch position is increased by performing scanning a plurality of times. The number of scans can be reduced as the change amount of the capacitance value per time is larger, that is, as the sensitivity is higher. As a result, the time from the touch to the determination of the position is shortened, leading to energy saving and an improved response speed to the touch. In order to increase the sensitivity, it is very important to reduce the resistance of the transparent conductive film.

  In a large-screen touch panel, the number of scans as described above has a more significant effect on the energy consumption and the response speed to touch. Therefore, the transparent conductive film of each of the above embodiments can be used for a capacitive touch panel regardless of a self-capacitance method, a mutual capacitance method, or the like. It can be preferably used.

  There is no particular limitation on the etching method of the transparent conductive film and the lead-out wiring, and a wet etching method using acid or alkali, or a dry etching method using a reactive plasma or a reactive ion beam in vacuum can be appropriately selected. . It is also possible to form a pattern using a liquid in which constituent elements are dispersed in a suitable binder in combination with a gravure printing method or an ink jet method.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments.

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

  In each of the following examples and comparative examples, a polyethylene terephthalate (PET) film having a thickness of 125 μm was used as the transparent substrate. The metal oxide thin film and metal thin film (silver-based thin film) of each Example and each Comparative Example were formed as follows.

The metal oxide thin film was formed by DC magnetron sputtering using a TiO ₂ target, Nb ₂ O ₅ target or SnO ₂ target, and ZnO target. The film forming conditions were Ar gas: 30 sccm and film forming pressure: 0.5 Pa. Film formation was performed by ternary simultaneous sputtering while adjusting the film formation power of the above three targets so that a metal oxide thin film having a desired composition ratio was obtained.

  The metal thin film was formed by DC magnetron sputtering using an AgPdCu (Ag: Pd: Cu = 99.0: 0.5: 0.5 (mass%)) target. The deposition conditions were Ar gas: 30 sccm, deposition pressure: 0.5 Pa, deposition power: 0.2 kW.

  The detailed structure of the transparent conductive film in each example and each comparative example will be described later. The evaluation method of the produced transparent conductive film is demonstrated below.

<Evaluation of color tone and transmittance>
About the color tone of the transmitted color, a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd .: HM-150) was used and evaluated by the values of “a *” and “b *” in the L * a * b * color system. If the values of “a *” and “b *” are in the range of −1 to +1, it is difficult to identify color change with the human eye, which is preferable. In order to ensure stable color reproducibility even when used for a long time, the values of “a *” and “b *” are preferably closer to zero.

<Evaluation of surface resistance and resistance stability at the outermost surface>
The surface resistance was measured using a four-terminal resistance measuring instrument. Continuous measurement for 15 seconds per point was performed at 10 different points. The average value (Rave) of the surface resistance indicated at all measurement points was determined. The rate of change when the maximum value of the surface resistance was Rmax and the minimum value was Rmin was determined by (Rmax−Rmin) / Rave × 100. A case where the rate of change was less than 10% was evaluated as “A”, and a case where the rate of change exceeded 10% was evaluated as “B”. The evaluation results are shown in the column of “resistance stability” in Tables 1 to 4. The transparent conductive film of evaluation “A” can secure stable conductivity with the lead-out wiring, and can secure stable driving performance when used for a touch panel.

<Evaluation of environmental resistance>
The environmental resistance was maintained for 200 hours in a thermostatic chamber in which the produced transparent conductive film was maintained at 85 ° C. and 85% RH. The width of decrease in transmittance after holding from before holding (transmittance before holding-transmittance after holding) is less than 1%, and the surface resistance (R1) after holding with respect to the surface resistance (R0) before holding When the rate of increase [(R1-R0) / R0] was less than 10%, it was evaluated as “A”, and the others were evaluated as “B”. When the transparent conductive film of evaluation “A” is used for a touch panel, stable driving performance can be ensured over a long period of time in the usage environment.

<Evaluation of flexibility>
Flexibility was evaluated by the rate of change (increase rate) in surface resistance before and after the film was wound around a cylinder of φ5 mm. The rate of change (increase rate) was calculated by the formula of (R1-R0) / R0 × 100, where R0 is the surface resistance value before winding and R1 is the surface resistance value after winding. The smaller the rate of change in surface resistance, the better. When the change rate of the surface resistance value before and after winding was less than 1.1%, it was evaluated as “A”, and when the change rate was 1.1% or more, it was evaluated as “B”. If the evaluation result is “A”, it is possible to avoid a situation in which the characteristics deteriorate due to the influence of handling or the like in the manufacturing process of the transparent conductive film or the touch panel. In addition, even when applied as a touch panel for a display panel having a curved surface, stable performance can be ensured.

  Tables 1 to 4 show the structures and characteristics of the produced transparent conductive films. Detailed structures and procedures in the individual embodiments are described below.

[Example 1]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets. In addition, the content rate of each metal element of Table 1-Table 4 is a mole fraction with respect to the sum total of three metal elements. Moreover, the calculated value of 26X + 23Y + 21Z or 26X + 19W + 21Z is shown in Table 1-Table 4 from the content rate of each metal element.

[Example 2]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (25 nm) are laminated in this order on the surface of the PET film to form a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 3]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (45 nm) are laminated in this order on the surface of the PET film to obtain a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 4]
A transparent conductive film as shown in FIG. 4 is formed by laminating a first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (15 nm) in this order on the surface of the PET film. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 5]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (55 nm) are laminated in this order on the surface of the PET film to form a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

  In Examples 1 to 5, the thickness of the second metal oxide thin film is changed. As shown in Table 1, in the metal oxide thin films of Examples 1 to 5, all of Ti, Nb, and Zn were in the range of 10 mol% to 80 mol%. The evaluation results of resistance stability, environmental resistance, and flexibility at these outermost surfaces were all “A”. Rave is about 16Ω / sq. 50Ω / sq. Lower and better.

  “A *” and “b *” in Examples 1 to 3 in which the film thickness of the second metal oxide thin film is in the range of 20 to 50 nm are in the range of −1 to +1, and the color reproducibility is good. there were. On the other hand, “b *” in Examples 4 to 5 deviating from the above range was larger than +1 and exhibited a change in color tone that was higher than a visible level.

[Example 6]
A transparent conductive film as shown in FIG. 1 is formed by laminating a first metal oxide thin film (39 nm), a metal thin film (5 nm), and a second metal oxide thin film (39 nm) in this order on the surface of the PET film. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 7]
A first metal oxide thin film (33 nm), a metal thin film (11 nm), and a second metal oxide thin film (33 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 8]
A transparent conductive film as shown in FIG. 1 is formed by laminating a first metal oxide thin film (39 nm), a metal thin film (4 nm), and a second metal oxide thin film (39 nm) in this order on the surface of the PET film. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

[Example 9]
A transparent conductive film as shown in FIG. 1 is formed by laminating a first metal oxide thin film (33 nm), a metal thin film (12 nm), and a second metal oxide thin film (33 nm) in this order on the surface of the PET film. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 1 by adjusting the power of three types of targets.

  In Examples 6 to 9, the film thickness of the metal thin film is changed. As shown in Table 1, in the metal oxide thin films of Examples 6 to 9, all of Ti, Nb, and Zn are in the range of 10 mol% to 80 mol%, and resistance stability and environmental resistance on the outermost surface And the evaluation results of flexibility were both “A”.

  In Examples 6 to 7 where the thickness of the metal thin film is in the range of 5 to 11 nm, Rave is 50 Ω / sq. Lower and better. On the other hand, “a *” and “b *” in Example 8 where the thickness of the metal thin film was 4 nm were in the range of −1 to +1. Thus, color reproducibility was good. However, the surface resistance is about 100 Ω / sq. It was high. In Example 9 where the thickness of the metal thin film is 12 nm, Rave is about 9 Ω / sq. It was low and good. On the other hand, “a *” was smaller than −1 and exhibited a change in color tone that was higher than a visible level.

[Comparative Example 1]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

[Comparative Example 2]
The first metal oxide thin film (35 nm), the metal thin film (8 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

  In Comparative Examples 1 and 2, the Ti content in the metal oxide thin film is changed. As shown in Table 2, in Comparative Example 1 in which the Ti content in the metal oxide thin film is 5 mol%, “a *” and “b *” are in the range of −1 to +1, and the color reproducibility is It was good. The surface resistance is about 16 Ω / sq. 50Ω / sq. Lower and better. The evaluation result of resistance stability and flexibility at the outermost surface was “A”. On the other hand, the increase rate of the surface resistance in the environmental resistance evaluation was 10% or more, which was insufficient.

  “A *” and “b *” of Comparative Example 2 in which the Ti content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance is about 13 Ω / sq, and 50 Ω / sq. Lower and better. The evaluation results of resistance stability and environmental resistance on the outermost surface were “A”. On the other hand, the increase rate of the surface resistance in the flexibility evaluation was 1.1% or more, which was insufficient.

[Comparative Example 3]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

[Comparative Example 4]
The first metal oxide thin film (35 nm), the metal thin film (8 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

  In Comparative Examples 3 to 4, the Nb content in the metal oxide thin film is changed. As shown in Table 2, “a *” and “b *” in Comparative Example 3 in which the Nb content in the metal oxide thin film is 5 mol% are in the range of −1 to +1, and the color reproducibility is good. Met. The surface resistance is about 16 Ω / sq. 50Ω / sq. Lower and better. The evaluation results of resistance stability and environmental resistance on the outermost surface were “A”. On the other hand, the increase rate of the surface resistance in the flexibility evaluation was 1.1% or more, which was insufficient.

  “A *” and “b *” of Comparative Example 4 in which the Nb content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance is about 13 Ω / sq. 50Ω / sq. Lower and better. The evaluation results of environmental resistance and flexibility were “A”. On the other hand, the rate of change in surface resistance in the resistance stability evaluation on the outermost surface was 10% or more, which was insufficient.

[Comparative Example 5]
A first metal oxide thin film (35 nm), a metal thin film (8 nm), and a second metal oxide thin film (35 nm) were laminated in this order on the surface of the PET film to produce a transparent conductive film. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

[Comparative Example 6]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (35 nm) were laminated in this order on the surface of the PET film to produce a transparent conductive film. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

  In Comparative Examples 5 to 6, the content of Zn in the metal oxide thin film is changed. As shown in Table 2, “a *” and “b *” in Comparative Example 5 in which the Zn content in the metal oxide thin film is 5 mol% are in the range of −1 to +1, and the color reproducibility is good. Met. The surface resistance is about 13 Ω / sq. 50Ω / sq. Lower and better. The evaluation result of environmental resistance and flexibility on the outermost surface was “A”. On the other hand, the rate of change in surface resistance in the resistance stability evaluation on the outermost surface was 10% or more, which was insufficient.

  Further, “a *” and “b *” of Comparative Example 6 in which the Zn content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance is about 16 Ω / sq. 50Ω / sq. Lower and better. The evaluation result of resistance stability and flexibility at the outermost surface was “A”. On the other hand, the increase rate of the surface resistance in the environmental resistance evaluation was 10% or more, which was insufficient.

[Example 10]
A first metal oxide thin film (29 nm), a metal thin film (7 nm), and a second metal oxide thin film (41 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

[Example 11]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

[Example 12]
On the surface of the PET film, a first metal oxide thin film (41 nm), a metal thin film (7 nm), and a second metal oxide thin film (29 nm) are laminated in this order to form a transparent conductive film as shown in FIG. Produced. The composition ratio of the 1st and 2nd metal oxide thin film was made to become the composition ratio of Table 2 by adjusting the power of three types of targets.

  In Examples 10 to 12, the compositions of the first metal oxide thin film and the second metal oxide thin film are different. As shown in Table 2, in Example 10, the value represented by 26X + 23Y + 21Z is different between the first metal oxide thin film and the second metal oxide thin film. In Example 10, out of the first metal oxide thin film and the second metal oxide thin film, the second metal oxide thin film having a smaller value represented by 26X + 23Y + 21Z is more than the first metal oxide thin film. The film thickness is thick. On the other hand, in Example 11, the first metal oxide thin film and the second metal oxide thin film have the same film thickness. In Example 12, of the first metal oxide thin film and the second metal oxide thin film, the second metal oxide thin film having a smaller value represented by 26X + 23Y + 21Z is the first metal oxide thin film. The film thickness is thinner than.

  As shown in Table 2, in the metal oxide thin films of Examples 10 to 12, all of Ti, Nb, and Zn were in the range of 10 to 80 mol%. The evaluation results of resistance stability, environmental resistance, and flexibility at the outermost surface were all “A”. Also, the surface resistance is about 16 Ω / sq. 50Ω / sq. Lower and better. On the other hand, the values of “a *” and “b *” are closest to zero in Example 10, and the values of “a *” and “b *” increase in the order of Example 11 and Example 12. I understood. From this, the second metal oxide thin film having a small value calculated by 26X + 23Y + 21Z has a larger film thickness than the first metal oxide thin film, so that color change is sufficiently suppressed and stable color reproduction is achieved. It was confirmed that the property was obtained.

[Example 13]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 14]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (25 nm) are laminated in this order on the surface of the PET film to form a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 15]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (45 nm) are laminated in this order on the surface of the PET film to obtain a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 16]
A transparent conductive film as shown in FIG. 4 is formed by laminating a first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (15 nm) in this order on the surface of the PET film. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 17]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (55 nm) are laminated in this order on the surface of the PET film to form a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

  In Examples 13 to 17, the thickness of the second metal oxide thin film is changed. As shown in Table 3, the metal oxide thin films of Examples 13 to 17 are all in the range of 10 to 80 mol% of Ti, Sn, and Zn, and have resistance stability, environmental resistance, and flexibility at the outermost surface. All of the evaluation results were “A”. Further, the surface resistance was about 16 Ω / sq in all cases, which was good lower than 50 Ω / sq.

  “A *” and “b *” in Examples 13 to 15 in which the film thickness of the second metal oxide thin film is in the range of 20 to 50 nm are in the range of −1 to +1, and the color reproducibility is good. there were. On the other hand, “b *” in Examples 16 to 17 in which the film thickness of the second metal oxide thin film deviates from the above range is larger than +1 and exhibits a change in color tone that is higher than a visible level. It was.

[Example 18]
A first metal oxide thin film (35 nm), a metal thin film (5 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film to form a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 19]
A first metal oxide thin film (34 nm), a metal thin film (11 nm), and a second metal oxide thin film (34 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 20]
The first metal oxide thin film (35 nm), the metal thin film (4 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film to obtain a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

[Example 21]
The first metal oxide thin film (34 nm), the metal thin film (12 nm), and the second metal oxide thin film (34 nm) are laminated in this order on the surface of the PET film to obtain a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 3 by adjusting the power of the three types of targets.

  In Examples 18 to 21, the film thickness of the metal thin film was changed. As shown in Table 3, the metal oxide thin films of Examples 18 to 21 are all in the range of 10 to 80 mol% of Ti, Sn, and Zn, and have resistance stability, environmental resistance, and flexibility at the outermost surface. All of the evaluation results were “A”.

  In Examples 18 to 19 in which the thickness of the metal thin film was in the range of 5 to 11 nm, the surface resistance was all lower than 50 Ω / sq. On the other hand, “a *” and “b *” in Example 20 in which the thickness of the metal thin film was 4 nm were in the range of −1 to +1, and the color reproducibility was good. However, the surface resistance was as high as about 100Ω / sq.

  The surface resistance of Example 21 in which the thickness of the metal thin film was 12 nm was as low as about 9 Ω / sq, which was good. On the other hand, “a *” was smaller than −1 and exhibited a change in color tone that was higher than a visible level.

[Comparative Example 7]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

[Comparative Example 8]
In the first embodiment, a first metal oxide thin film (35 nm), a metal thin film (8 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the same as in FIG. A transparent conductive film having the following structure was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

  In Comparative Examples 7 to 8, the Ti content in the metal oxide thin film is changed. As shown in Table 4, “a *” and “b *” in Comparative Example 7 in which the Ti content in the metal oxide thin film is 5 mol% are in the range of −1 to +1, and the color reproducibility is good. Met. The surface resistance was about 16 Ω / sq, which was better than 50 Ω / sq. The evaluation result of resistance stability and flexibility at the outermost surface was “A”. On the other hand, the increase rate of the surface resistance in the environmental resistance evaluation was 10% or more, which was insufficient.

  “A *” and “b *” in Comparative Example 8 in which the Ti content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance was about 13 Ω / sq, which was better than 50 Ω / sq. In addition, the evaluation results of resistance stability and environmental resistance on the outermost surface were “A”. On the other hand, the increase rate of the surface resistance in the flexibility evaluation was 1.1% or more, which was insufficient.

[Comparative Example 9]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

[Comparative Example 10]
The first metal oxide thin film (35 nm), the metal thin film (6 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

In Comparative Examples 9 to 10, the Sn content in the metal oxide thin film is changed. As shown in Table 4, in Comparative Example 9 in which the Sn content in the metal oxide thin film is 5 mol%, “a *” and “b *” are in the range of −1 to +1, and the color reproducibility is It was good. The surface resistance was about 16 Ω / sq, which was better than 50 Ω / sq. The evaluation results of resistance stability and environmental resistance on the outermost surface were “A”. On the other hand, the increase rate of the surface resistance in the flexibility evaluation was 1.1% or more, which was insufficient.

  “A *” and “b *” of Comparative Example 10 in which the Sn content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance was about 23 Ω / sq, which was better than 50 Ω / sq. The evaluation results of environmental resistance and flexibility were “A”. On the other hand, the rate of change in surface resistance in the resistance stability evaluation on the outermost surface was 10% or more, which was insufficient.

[Comparative Example 11]
The first metal oxide thin film (35 nm), the metal thin film (6 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

[Comparative Example 12]
The first metal oxide thin film (35 nm), the metal thin film (7 nm), and the second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and the transparent conductive material having the same structure as FIG. A film was prepared. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

  In Comparative Examples 11 to 12, the Zn content in the metal oxide thin film is changed. As shown in Table 4, “a *” and “b *” in Comparative Example 11 in which the Zn content in the metal oxide thin film is 5 mol% are in the range of −1 to +1, and the color reproducibility is good. Met. The surface resistance was about 23 Ω / sq, which was better than 50 Ω / sq. The evaluation result of environmental resistance and flexibility on the outermost surface was “A”. On the other hand, the rate of change in surface resistance in the resistance stability evaluation on the outermost surface was 10% or more, which was insufficient.

  “A *” and “b *” of Comparative Example 12 in which the Zn content in the metal oxide thin film was 85 mol% were in the range of −1 to +1, and the color reproducibility was good. The surface resistance was about 16 Ω / sq, which was better than 50 Ω / sq. The evaluation result of resistance stability and flexibility at the outermost surface was “A”. On the other hand, the increase rate of the surface resistance in the environmental resistance evaluation was 10% or more, which was insufficient.

[Example 22]
A first metal oxide thin film (30 nm), a metal thin film (7 nm), and a second metal oxide thin film (41 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

[Example 23]
A first metal oxide thin film (35 nm), a metal thin film (7 nm), and a second metal oxide thin film (35 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets.

[Example 24]
A first metal oxide thin film (41 nm), a metal thin film (7 nm), and a second metal oxide thin film (30 nm) are laminated in this order on the surface of the PET film, and a transparent conductive film as shown in FIG. Produced. The composition ratios of the first and second metal oxide thin films were adjusted to the composition ratios shown in Table 4 by adjusting the power of the three types of targets. In Examples 22 to 24, the compositions of the first metal oxide thin film and the second metal oxide thin film are different.

  As shown in Table 4, in Example 22, the value represented by 26X + 19W + 21Z is different between the first metal oxide thin film and the second metal oxide thin film. That is, of the first metal oxide thin film and the second metal oxide thin film, the thickness of the second metal oxide thin film having a smaller value represented by 26X + 19W + 21Z is larger than that of the first metal oxide thin film. It is thick. On the other hand, in Example 23, the first metal oxide thin film and the second metal oxide thin film have the same film thickness. In Example 24, of the first metal oxide thin film and the second metal oxide thin film, the second metal oxide thin film having a smaller value represented by 26X + 19W + 21Z is more than the first metal oxide thin film. The film thickness is thin.

  As shown in Table 4, the metal oxide thin films of Examples 22 to 24 are all in the range of 10 to 80 mol% of Ti, Sn, and Zn, and have resistance stability, environmental resistance, and flexibility at the outermost surface. All of the evaluation results were “A”. Further, the surface resistance was about 16 Ω / sq in all cases, which was good lower than 50 Ω / sq. On the other hand, the average values of “a *” and “b *” are closest to zero in Example 22, and the average values of “a *” and “b *” increase in the order of Example 23 and Example 24. I found out. Since the second metal oxide thin film having a smaller value calculated by 26X + 19W + 21Z has a larger film thickness than the first metal oxide thin film, the color tone change is sufficiently suppressed, and stable color reproducibility is achieved. It was confirmed that it was obtained.

[Example 25]
A touch panel was prepared according to the following procedure. A resist pattern was formed on the surface of the transparent conductive film prepared in Example 1 using a phenol-based positive photoresist (manufactured by Kanto Chemical Co., Ltd .: OFPR-800LB) so as to correspond to the shape of the pattern 52 in FIG. . Then, the resist pattern was used as a mask, and the transparent conductive film was immersed in an etching solution (Fuji Giken Kogyo Co., Ltd .: Chromat IT) maintained at 23 ° C. for 1 minute. Thereby, the transparent conductive film (the first metal oxide thin film, the metal thin film, and the second metal oxide thin film) in the unmasked portion is etched to form an insulating portion, and the transparent conductive film shown in FIGS. A first pattern 52 composed of the film 60 was produced. Then, the 2nd pattern 54 comprised by transparent conductive film 60 'of FIG. 7, 8 was produced by the process same as the process of forming the 1st pattern 52. FIG.

  Subsequently, a lead wire 48 shown in FIGS. 7 and 8 (drawer wire 58 shown in FIG. 9) was formed by an inkjet method using a paste in which Cu fine particles were dispersed in the produced first pattern 52 and second pattern 54. .

  Then, the 1st pattern transparent conductive film and the 2nd pattern transparent conductive film were bonded together as shown in FIG.8 and FIG.9 using the optical adhesive agent, and the touch panel was produced.

  The touch panel was bonded to the liquid crystal panel with an adhesive, and the color tone of the display image was visually confirmed. As a result, it was confirmed that the display color of the liquid crystal panel hardly changed before and after the touch panel was bonded, and that high color reproducibility was realized.

  In addition, 4 inch, 7 inch, 10 inch, and 14 inch touch panels were produced by the above-described methods. These touch panels were bonded to a liquid crystal panel and a protective panel, and the accuracy and response speed with respect to finger contact were evaluated. As a result, it was confirmed that the contact position was detected at almost the same response speed without erroneous recognition in any size.

  According to the present invention, it is possible to provide a transparent conductive film that exhibits a stable resistance value on the outermost surface and has both high flexibility and high environmental resistance. Moreover, the touch panel excellent in the above-mentioned characteristic can be provided by using the said transparent conductive film.

  10a, 10b, 10c ... transparent conductive film, 12, 12 '... transparent substrate, 13 ... functional resin layer, 14 ... adhesion layer, 15, 15' ... first metal oxide thin film, 16, 16 '... metal Thin film, 18, 18 '... second metal oxide thin film, 20a, 20b ... transparent conductive film, 30 ... transparent conductive film, 32 ... transparent conductive part, 34 ... insulating part, 40a, 40b, 50 ... touch panel, 42 ... transparent adhesive layer, 44 ... first transparent conductive film, 46 ... second transparent conductive film, 48, 58 ... lead-out wiring, 52 ... X transparent wiring (pattern), 54 ... Y transparent wiring (pattern) ).

Claims (5)

A transparent conductive film comprising a transparent substrate and a transparent conductive film on the transparent substrate,
The transparent conductive film has a three-layer structure having a metal thin film and a pair of metal oxide thin films sandwiching the metal thin film,
The metal elements contained in the pair of metal oxide thin films are mainly Ti, Nb or Sn, and Zn,
The transparent conductive film whose content rate of Ti, Nb or Sn, and Zn is 10-80 mol% on the basis of these sum totals. The metal elements contained in the pair of metal oxide thin films are mainly Ti, Nb and Zn,
Of the pair of metal oxide thin films, when the Ti content is X, the Nb content is Y, and the Zn content is Z, the smaller one of 26X + 23Y + 21Z has a larger film thickness. 1. The transparent conductive film according to 1. The metal elements contained in the pair of metal oxide thin films are mainly Ti, Sn and Zn,
2. Of the pair of metal oxide thin films, when the Ti content is X, the Sn content is W, and the Zn content is Z, the smaller value of 26X + 19W + 21Z has a larger film thickness. The transparent conductive film described in 1.   4. The transparent conductive film according to claim 1, wherein the metal thin film has a thickness of 5 to 11 nm, and the pair of metal oxide thin films has a thickness of 20 to 50 nm, respectively.   A touch panel provided with the transparent conductive film of any one of Claims 1-4.

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