JP5958476B2 - Transparent conductor and touch panel - Google Patents

Description

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

  Transparent electrodes are used in display devices such as a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence panel (organic EL, inorganic EL), a touch panel, and an electrochromic element. Such a transparent electrode is normally comprised by the transparent conductor which has a base material and the transparent conductive layer produced on the base material. The transparent conductor can also be used as a transparent electromagnetic wave shielding film.

  A touch panel (also referred to as a touch switch or a flat switch) is an information input device disposed on a display surface such as a liquid crystal device. Touch panels are widely used in electronic devices such as mobile phones, car navigation systems, personal computers, ticket vending machines, and bank ATM terminals.

  The touch panel includes a pair of panel plates having a transparent conductive layer. When a finger or a touch pen touches or approaches the instruction image displayed in the image display area of the touch panel, the position is detected. Thus, the information corresponding to the instruction image can be input. There are several methods for detecting the position of the touch panel, and among them, a resistive film method and a capacitance method are mainly used. Since the touch panel is operated via the display, the transparent conductor used for the touch panel is required to have high transmittance.

  Among the capacitive methods, the projected capacitive touch panel is excellent in multipoint input. For this reason, the demand for projection capacitive touch panels for mobile phones and tablet PCs is greatly expanding. In this method, the transparent conductive layer is processed into a predetermined pattern for sensing. For this reason, the transparent conductor has a conductive part having a transparent conductive layer and a non-conductive part not having a transparent conductive layer. Therefore, the projected capacitive touch panel has a unique situation that the sensing pattern is easily recognized.

  Here, residual stress is generated in the transparent conductor due to shrinkage of the base material due to heating such as crystallization treatment. For this reason, when a transparent conductive layer is processed into a predetermined pattern, it is known that waviness may occur at the boundary between the conductive part and the non-conductive part, resulting in a step (see, for example, Patent Document 1). In order to prevent such a phenomenon, a method has been proposed in which the heat shrinkage of the substrate is reduced by lowering the heating temperature of the transparent conductor.

JP2013-043372A

  When the transparent conductive layer is patterned for sensing to form a conductive portion and a non-conductive portion, the sensing pattern is easily visible. Such a phenomenon appears more prominently when the transparent conductor is thinned. As means for solving such a problem, it is conceivable to increase the thickness of the transparent conductor or to lower the heating temperature of the transparent conductor. However, in recent years, there is a strong demand for making the touch panel thinner, so it is difficult to increase the thickness of the transparent conductor. Further, if the heating temperature of the transparent conductor is lowered in order to suppress the step, it is inevitably necessary to lengthen the heating time. Such means is not preferable from the viewpoint of productivity. For this reason, it is required to establish another technique capable of sufficiently suppressing the step at the boundary between the conductive part and the non-conductive part and making it difficult to visually recognize the sensing pattern.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transparent conductor that has a high total light transmittance and has a sensing pattern that is hardly visible even when the transparent conductor is thinned. . Another object of the present invention is to provide a touch panel that uses a transparent conductor as described above and has a clear display and a sensing pattern that is difficult to visually recognize.

  As a result of intensive studies to solve the above problems, the present inventors provide at least three optical adjustment layers between the transparent substrate and the transparent conductive layer in the transparent conductor having the transparent substrate and the transparent conductive layer. It has been found that the above problems can be solved.

That is, in this invention, it is a transparent conductor provided with a transparent base material, a transparent conductive layer, and an optical adjustment layer between a transparent base material and a transparent conductive layer, Comprising: An optical adjustment layer is from a transparent base material side. , The first optical adjustment layer, the second optical adjustment layer, and the third optical adjustment layer, the first optical adjustment layer contains a cured resin, and the second optical adjustment layer is nitrided Silicon or silicon nitride and silicon oxide are contained, the third optical adjustment layer contains silicon oxide, and the refractive indexes of the first optical adjustment layer, the second optical adjustment layer, and the third optical adjustment layer are set. Provide transparent conductors satisfying the following formula (1) when n1, n2 and n3, respectively.
n2>n1> n3 (1)

  According to the present invention, it is possible to obtain a transparent conductor that has a high total light transmittance and has a sufficiently suppressed level difference at the boundary between the conductive part and the non-conductive part even if the transparent conductor is thin. it can. In this invention, since it has the 1st-3rd optical adjustment layer which satisfy | fills Formula (1), it can be set as the transparent conductor which has a high total light transmittance. In addition, although the cause which can make the level | step difference of the boundary part of a sensing pattern small is not necessarily clear, the present inventors guess as follows.

  As one of the factors that cause a step at the boundary of the sensing pattern, the transparent conductive layer in the conductive part has a strong compressive stress, whereas such a transparent conductive layer is removed in the non-conductive part. It is mentioned. Since there is such a stress difference, it can be estimated that a step is generated in the transparent conductor. Here, since the 2nd optical adjustment layer of this invention contains the silicon nitride which has a larger compressive stress than resin hardened | cured material and silicon oxide, it accompanies the difference of the compressive stress of a conductive part and a non-conductive part. It is considered that the occurrence of undulation is suppressed and the step at the boundary can be reduced. Since the second optical adjustment layer containing silicon nitride has a large compressive stress, it tends to be warped with heating. The first optical adjustment layer of the present invention is considered to have a function of reducing such warpage.

  In the second optical adjustment layer, the ratio of silicon nitride to the total of silicon nitride and silicon oxide is preferably 40 mol% or more. By increasing the molar ratio of silicon nitride, the step at the boundary can be further reduced. The thickness of the first optical adjustment layer is preferably 10 to 80 nm, and the thickness of the second optical adjustment layer is preferably 1 to 25 nm. Accordingly, the amount of curl can be sufficiently reduced by suppressing the occurrence of warping while reducing the level difference at the boundary.

The thickness of the third optical adjustment layer is preferably 1 to 40 nm. Thus, the absolute value of the b ^* value of transmitted light in the conductive portion and the nonconductive portion is small, to reduce the difference between the b ^* value of transmitted light b ^* values and the non-conductive portion of the light transmitted through the conductive portion be able to. This makes it harder to recognize the sensing pattern and sufficiently suppresses the transmitted light from being colored yellow.

  The thickness of the transparent conductor is preferably 130 μm or less. This makes the transparent conductor of the present invention more useful in the technical field where it is required to make the transparent conductor thin. The transparent conductor of the present invention can make the sensing pattern difficult to be visually recognized even if the thickness is reduced in this way.

  The transparent conductive film preferably has a warp suppressing layer containing silicon nitride or silicon nitride and silicon oxide on the side opposite to the optical adjustment layer side of the transparent substrate. As a result, the curl amount can be sufficiently reduced. The transparent conductor may have a protective film on the side opposite to the optical adjustment layer side of the transparent substrate. As a result, the amount of curling can be further reduced by further suppressing warpage.

  The present invention provides a touch panel in which a panel plate and a sensor film are arranged to face each other via a spacer, and the sensor film is the above-described transparent conductor. Since such a touch panel includes the transparent conductor having the above-described characteristics as a sensor film, the sensing pattern is hardly visible and the display can be made clear.

  According to the present invention, it is possible to provide a transparent conductor that has a high total light transmittance and is difficult to visually recognize a sensing pattern even if the transparent conductor is thinned. Further, by using this transparent conductor, it is possible to provide a touch panel that has a clear display and is difficult to visually recognize the sensing pattern.

FIG. 1 is a cross-sectional view schematically showing one embodiment of the transparent conductor of the present invention. FIG. 2 is a schematic cross-sectional view showing an enlarged part of a cross section of the touch panel of the present invention. 3 (A) and 3 (B) are plan views of a sensor film constituting the touch panel. FIG. 4 is a cross-sectional view schematically showing another embodiment of the transparent conductor of the present invention. FIG. 5 is a diagram for explaining a method of measuring the curl amount of the transparent conductor. FIG. 6 is a cross-sectional view schematically showing an evaluation sample for measuring a step.

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

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a transparent conductor. The transparent conductor 100 includes a film-like transparent substrate 10 and a transparent conductive layer 16, and an optical adjustment layer 11 including a plurality of layers having different compositions between the transparent substrate 10 and the transparent conductive layer 16. The transparent conductor 100 further includes a pair of hard coat layers 20 so as to sandwich the transparent substrate 10 therebetween. The optical adjustment layer 11 has a structure in which a first optical adjustment layer 13, a second optical adjustment layer 14, and a third optical adjustment layer 15 are laminated from the transparent substrate 10 toward the transparent conductive layer 16. .

  A first hard coat layer 22 is provided between the transparent substrate 10 and the first optical adjustment layer 13. Further, a second hard coat layer 24 is provided on the opposite side of the transparent substrate 10 from the first hard coat layer 22. That is, the transparent conductor 100 includes the second hard coat layer 24, the transparent substrate 10, the first hard coat layer 22, the first optical adjustment layer 13, the second optical adjustment layer 14, and the third optical adjustment. The layer 15 and the transparent conductive layer 16 have a stacked structure in which they are stacked in this order.

(Transparent substrate 10)
The transparent substrate 10 is, for example, a flexible organic resin film or organic resin sheet. “Transparent” in the present specification means that visible light is transmitted, and the light may be scattered to some extent. Regarding the degree of light scattering, the required level varies depending on the use of the transparent conductor 100. What has light scattering generally referred to as translucent is also included in the concept of “transparency” in this specification. The degree of light scattering is preferably small, and the transparency is preferably high. The total light transmittance of the entire transparent conductor 100 is, for example, 86% or more, and preferably 89% or more.

  As the transparent substrate 10, an organic resin film having flexibility is suitable. Examples of the resin film include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polycarbonate films, acrylic films, norbornene films, polyarylate films, polyether sulfone films, A diacetyl cellulose film, a triacetyl cellulose film, etc. are mentioned. Of these, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferable.

  The transparent substrate 10 is preferably thicker from the viewpoint of rigidity. On the other hand, the transparent substrate 10 is preferably thin from the viewpoint of thinning the transparent conductor 100. From such a viewpoint, the thickness of the transparent substrate 10 is, for example, 10 to 130 μm. The refractive index of the transparent substrate is, for example, 1.50 to 1.70 from the viewpoint of making a transparent conductor excellent in optical characteristics. The refractive index in this specification is a value measured under the conditions of λ = 633 nm and a temperature of 20 ° C.

  The transparent substrate 10 preferably has high dimensional stability during heating. In general, a flexible organic resin film undergoes a dimensional change due to expansion or contraction due to heating during the film production process. By carrying out uniaxial stretching or biaxial stretching in the production process of the organic resin film, the transparent substrate 10 having a small thickness can be produced at low cost. When the transparent conductor 100 is heated in the step of crystallizing the transparent conductive layer 16 or the step of forming the extraction electrode, the transparent substrate 10 is thermally contracted to cause a dimensional change. Such a dimensional change can be measured according to ASTM D1204 or JIS-C-2151.

The heat treatment for crystallizing the transparent conductive layer 16 is usually performed at a heating temperature of 140 ° C. and a heating time of about 90 minutes. The dimensional change rate before and after the heat treatment can be obtained by the following formula, where Lo is the dimension before heating and L is the dimension after heating.
Dimensional change rate (%) = 100 × (L-Lo) / Lo

  When the rate of dimensional change (%) is positive, it indicates that it has expanded by heat treatment, and when it is negative, it indicates that it has shrunk by heat treatment. The dimensional change rate of the biaxially stretched transparent substrate 10 can be measured in both the traveling direction (MD direction) and the transverse direction (TD direction) during stretching. The dimensional change rate of the transparent 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 substrate 10 may have a large amount of heat shrinkage caused by heating or may have a small amount of heat shrinkage. Examples of the transparent substrate 10 having a small heat shrinkage include a polycarbonate substrate and a cycloolefin substrate.

  The transparent substrate 10 may be subjected to at least one surface treatment selected from the group consisting of corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, and ozone treatment. .

  When the transparent conductor 100 is used as the transparent electrode panel plate on the input side (front side) of the pair of transparent electrode panel plates constituting the touch panel, it can be appropriately deformed with respect to external inputs such as a finger and a pen. The transparent substrate 10 is preferably a flexible organic resin film. On the other hand, when the transparent conductor 100 is used as an internal-side transparent electrode panel plate disposed to face the input-side (surface-side) transparent electrode panel plate, flexibility is not required. May be a non-flexible glass plate.

(Hard coat layer 20)
The transparent conductor 100 includes a pair of hard coat layers 20 (a first hard coat layer 22 and a second hard coat layer 24) so as to sandwich the transparent substrate 10 therebetween. The hard coat layer 20 is provided to prevent scratches on the transparent conductor 100. The hard coat layer 20 contains a cured resin obtained by curing the resin composition. The resin composition preferably contains at least one selected from a thermosetting resin composition, an ultraviolet curable resin composition, and an electron beam curable resin composition. The thermosetting resin composition may include at least one selected from an epoxy resin, a phenoxy resin, and a melamine resin.

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

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

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

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

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

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

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

  The average particle diameter of the fine particles is smaller than the thickness of the hard coat layer 20 and may be 100 nm or less or 20 nm or less from the viewpoint of ensuring sufficient transparency. On the other hand, the average particle diameter of the fine particles may be 5 nm or more, or 10 nm or more from the viewpoint of production of the colloidal solution. 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 weight or 20 to 200 parts by weight with respect to 100 parts by weight of the curable compound. May be.

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

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

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

  In addition, the thickness of each layer which comprises the transparent conductor 100 can be measured in the following procedures. The transparent conductor 100 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.

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

  On the first hard coat layer 22, the optical adjustment layer 11 composed of a plurality of layers having different compositions is laminated. The optical adjustment layer 11 is provided with a first optical adjustment layer 13, a second optical adjustment layer 14, and a third optical adjustment layer 15 in this order from the first hard coat layer 22 side. The optical adjustment layer 11, that is, the first optical adjustment layer 13, the second optical adjustment layer 14, and the third optical adjustment layer 15 reduce the reflectance of the surface of the transparent conductive layer 16 due to optical interference, and reduce the total light. A layer for increasing the transmittance is formed. The first optical adjustment layer 13, the second optical adjustment layer 14, and the third optical adjustment layer 15 suppress an optical difference and a step due to the presence or absence of the transparent conductive layer 16 caused by the sensing pattern. The optical adjustment layer 11 has a function of making the sensing pattern difficult to recognize and also has a function of improving visibility.

(First optical adjustment layer 13)
The first optical adjustment layer 13 contains, for example, a cured resin obtained by curing the resin composition with energy rays, like the first hard coat layer 22. As the resin composition, the same resin composition as that described for the first hard coat layer 22 can be used. As the resin composition, the same energy ray curable resin composition as described in the first hard coat layer 22 is used. That is, the resin composition is an energy ray curable resin composition containing a curable compound having an energy ray reactive group selected from a (meth) acryloyl group and a vinyl group. The resin composition preferably contains a polymer having a high refractive index.

The resin composition may contain metal oxide fine particles. Examples of the metal oxide fine particles include titanium oxide (TiO ₂ , refractive index: 2.35), zirconium oxide (ZrO ₂ , refractive index: 2.05), cerium oxide (CeO ₂ , refractive index: 2.30), Niobium oxide (Nb ₂ O ₃ , refractive index: 2.15), antimony oxide (Sb ₂ O ₃ , refractive index: 2.10), tantalum oxide (Ta ₂ O ₅ , refractive index: 2.10), and these And a combination of two or more. A resin composition in which such fine particles are dispersed in a curable compound is applied onto the first hard coat layer 22 and cured, whereby a first optical material containing a cured resin and metal oxide fine particles is obtained. The adjustment layer 13 can also be produced. The fine particles may be, for example, 5 to 500 parts by weight or 20 to 200 parts by weight with respect to 100 parts by weight of the curable compound. As the content of the fine particles decreases, the refractive index of the first optical adjustment layer 13 tends to decrease.

The refractive index (n1) of the first optical adjustment layer 13 is preferably higher than the refractive index of the first hard coat layer 22, and may be 1.55 to 1.80, for example, 1.57 to It may be 1.67. If the refractive index of the first optical adjustment layer 13 is too low, the total light transmittance at the portion (conductive portion) where the transparent conductive layer is present in the sensing pattern tends to decrease. On the other hand, when the pattern is formed when the refractive index of the first optical adjustment layer 13 is too high, the b ^* value of the transmitted light at the portion where the transparent conductive layer 16 is removed (non-conductive portion) is reduced to the negative side. There is a tendency. That is, a color difference tends to occur in the transmitted light depending on the sensing pattern.

  The thickness of the first optical adjustment layer 13 may be 10 to 80 nm or 15 to 75 nm. If the first optical adjustment layer 13 becomes too thin, the production of the first optical adjustment layer 13 by application tends to be difficult. Further, the effect of suppressing warpage tends to be reduced. On the other hand, when the first optical adjustment layer 13 becomes too thick, the total light transmittance tends to be low at a portion where the transparent conductive layer is present (conductive portion).

As a resin composition for producing the first optical adjustment layer 13, for example, TYT80 (trade name, refractive index: titanium oxide (TiO ₂ ) dispersed in an acrylic energy ray curable resin composition. 1.80, manufactured by Toyo Ink Co., Ltd.), TYZ62 (trade name, refractive index: 1.62, Toyo Ink (ZrO ₂ ) dispersed in an acrylic energy ray-curable resin composition) Etc.). A resin composition containing a polymer having a high refractive index may be used. Examples of the high refractive index polymer include UR-101 (trade name, refractive index: 1.70, manufactured by Nissan Chemical Industries).

On the 1st hard-coat layer 22, the above-mentioned resin composition is apply | coated and dried, Then, an ultraviolet irradiation is performed and it hardens | cures, The 1st optical adjustment layer 13 is produced. The coating method at this time can be performed by a 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. Such a coating method is preferable to a vacuum film forming method using a sputtering method or the like from the viewpoint of manufacturing cost.

  After producing the 1st optical adjustment layer 13, the laminated | multilayer film containing the transparent base material 10, the 1st hard-coat layer 22, and the 1st optical adjustment layer 13 may be shrunk by the heating using a drying furnace. . Thereby, in the step of forming the second optical adjustment layer 14, the third optical adjustment layer 15, and the transparent conductive layer 16, the shrinkage of the transparent substrate 10 can be suppressed and the generation of wrinkles can be suppressed. The drying temperature in the drying furnace is, for example, 110 to 150 ° C. If the temperature is less than 110 ° C., the transparent substrate 10 tends to shrink due to heat during film formation, and wrinkles tend to occur. On the other hand, when the temperature exceeds 150 ° C., the transparent base material 10 is excessively contracted in the drying furnace and tends to cause wrinkles.

  The first optical adjustment layer 13 has a function of suppressing the occurrence of warping (curling) of the transparent conductor 100. Since the second optical adjustment layer 14 provided on the transparent conductor 100 contains silicon nitride, warping tends to occur when the transparent conductor 100 is heated. The first optical adjustment layer 13 has a function of reducing generated warpage. The composition of the first optical adjustment layer 13 is, for example, a transmission electron microscope (TEM) or scanning a cut surface obtained by cutting the transparent conductor 100 using a focused ion beam device (FIB). It can obtain | require by analyzing using the energy dispersive X-ray spectrometer (EDS: energy dispersive X-ray spectrometry) attached to an electron microscope (SEM).

(Second optical adjustment layer 14)
The second optical adjustment layer 14 contains silicon nitride, or silicon nitride and silicon oxide. In the second optical adjustment layer 14, the molar ratio of silicon nitride to the total of silicon nitride and silicon oxide may be 30 mol% or more, 40 mol% or more, or 50 mol% or more. . By increasing the molar ratio of silicon nitride, the step at the boundary of the sensing pattern can be sufficiently reduced. The composition of the second optical adjustment layer 14 can be obtained in the same manner as the composition of the first optical adjustment layer 13.

  The second optical adjustment 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, the sputtering method is preferable in that the film forming chamber can be reduced in size. The sputtering method is particularly preferable when there are a plurality of layers to be formed.

  In the sputtering method, the second optical adjustment layer 14 can be formed on the first optical adjustment layer 13 by a reactive sputtering method using an oxide target, a metal or metalloid target, and a reactive gas. . The reactive sputtering method is a method of forming a metal or metalloid oxide or nitride film by adding a reactive gas such as oxygen or nitrogen to an inert gas such as argon gas. The reactive sputtering method using a metal or metalloid target can increase the deposition rate as compared with the case of using an oxide target.

  The refractive index (n2) of the second optical adjustment layer 14 is set higher than the refractive index (n1) of the first optical adjustment layer 13, and may be 1.62 to 2.30. .69 to 2.10. If the refractive index (n2) is too low, the total light transmittance in the portion where the transparent conductive layer is present (conductive portion) is lowered, so the portion where the transparent conductive layer is present (conductive portion) and the portion where the transparent conductive layer is not present (non-conductive portion). The difference in total light transmittance tends to increase. If the refractive index (n2) is too high, the total light transmittance at the non-conductive part is lowered, and the difference between the total light transmittances at the conductive part and the non-conductive part tends to be large.

The second optical adjustment layer 14 includes the following trace components in addition to silicon nitride (Si ₃ N ₄ , refractive index: 2.00) and silicon oxide (SiO ₂ .refractive index: 1.46). You may go out. Examples of the trace component include titanium oxide (TiO ₂ , refractive index: 2.35), zirconium oxide (ZrO, refractive index: 2.05), cerium oxide (CeO ₂ , refractive index: 2.30), niobium oxide. (Nb ₂ O ₅ , refractive index: 2.30), antimony oxide (Sb ₂ O ₅ refractive index 2.10), and tantalum oxide (Ta ₂ O ₃ , refractive index: 2.10). The total ratio of silicon nitride and silicon oxide to the entire second optical adjustment layer is, for example, 90 mol% or more and 95 mol% or more. The ratio of silicon nitride and silicon oxide can be adjusted by changing the composition of the reactive gas in the reactive sputtering method.

  The thickness of the second optical adjustment layer 14 may be 1 to 25 nm, 2 to 23 nm, or 3 to 10 nm. From the viewpoint of shortening the time required for producing the second optical adjustment layer 14, the second optical adjustment layer 14 is preferably thin. However, if the second optical adjustment layer 14 becomes too thin, the level difference at the boundary between the conductive portion and the non-conductive portion tends to increase. On the other hand, if the second optical adjustment layer 14 becomes too thick, the warp of the transparent conductor 100 tends to increase.

(Third optical adjustment layer 15)
The third optical adjustment layer 15 contains silicon oxide. The composition of the third optical adjustment layer 15 can be obtained in the same manner as the composition of the first optical adjustment layer 13. Similar to the second optical adjustment layer 14, the third optical adjustment layer 15 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, the sputtering method is preferable in that the film forming chamber can be reduced in size. Since the transparent conductor 100 has a plurality of layers produced by a vacuum film forming method, the sputtering method is particularly preferable.

  In the sputtering method, similarly to the second optical adjustment layer 14, the third layer is formed on the second optical adjustment layer 14 by a reactive sputtering method using an oxide target, a metal or metalloid target, and a reactive gas. The optical adjustment layer 15 can be produced. The reactive sputtering method using a metal or metalloid target can increase the deposition rate as compared with the case of using an oxide target.

The refractive index (n3) of the third optical adjustment layer 15 is set lower than the refractive index (n1) of the first optical adjustment layer 13 and the refractive index (n2) of the second optical adjustment layer 14. That is, the following formula (1) is established. The refractive index (n3) may be 1.35 to 1.55 or 1.35 to 1.52. From the viewpoint of optical characteristics, the refractive index (n3) is preferably low. However, if the refractive index (n3) is too low, the layer density tends to be low. From such a viewpoint, the refractive index (n3) is preferably 1.35 or more. When the refractive index (n3) is high, the thickness of the third optical adjustment layer 15 required for increasing the total light transmittance tends to increase. From such a viewpoint, the refractive index (n3) is preferably 1.55 or less, and more preferably 1.52 or less.
n2>n1> n3 (1)

The third optical adjustment layer 15 may contain the following minor components in addition to silicon oxide (SiO ₂ , refractive index: 1.46). Examples of the trace component include lithium fluoride (LiF, refractive index: 1.36), magnesium fluoride (MgF, refractive index: 1.38), calcium fluoride (CaF ₂ , refractive index: 1.4), And cerium fluoride (CeF, refractive index: 1.63). The content of silicon oxide in the third optical adjustment layer 15 is, for example, 90 mol% or more and 95 mol% or more. The content of silicon oxide can be adjusted by changing the reactive gas in the reactive sputtering method.

The thickness of the third optical adjustment layer 15 may be 1 to 40 nm, 7 to 40 nm, or 12 to 30 nm. If the third optical adjustment layer 15 becomes too thin, the total light transmittance of the transparent conductor 100 tends to decrease. On the other hand, if the third optical adjustment layer 15 becomes too thick, the absolute value of the difference in b ^* value of the transmitted light between the conductive portion and the non-conductive portion increases, and the sensing pattern tends to be easily recognized.

(Transparent conductive layer 16)
The transparent conductive layer 16 is a thin film made of a metal (or metalloid) oxide. Examples of the oxide include tin oxide, indium oxide, zinc oxide, titanium oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. It is done. Of these, indium-tin composite oxide is preferable. The content of tin oxide in the indium-tin composite oxide is, for example, 3 to 12% by weight. The composition of the transparent conductive layer 16 can be obtained in the same manner as the composition of the first optical adjustment layer 13.

  The transparent conductive layer 16 is provided on the third optical adjustment layer 15. The transparent conductive layer 16 may cover the entire one surface of the third optical adjustment layer 15 or may cover only a part thereof. That is, the transparent conductive layer 16 may be patterned so as to cover a part of the one surface. The transparent conductive 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, the sputtering method is preferable in that the film forming chamber can be downsized. Since the transparent conductor 100 has a plurality of layers produced by a vacuum film forming method, the sputtering method is particularly preferable.

  The thickness of the transparent conductive layer 16 is, for example, 10 to 50 nm from the viewpoint of the resistance value and the total light transmittance. The refractive index of the transparent conductive layer 16 is preferably low. The refractive index of indium-tin composite oxide is around 2.05. The thickness of the transparent conductive layer 16 is, for example, 10 to 50 nm. If the transparent conductive layer 16 is too thin, it does not become dense and the resistance value tends to be unstable. On the other hand, if the transparent conductive layer 16 is too thick, the total light transmittance tends to be low.

  The surface resistance value of the transparent conductive layer 16 is preferably low, and may be, for example, 300Ω / □ (300Ω / sq.) Or less, or 50 to 300Ω / □.

  The transparent conductor 100 having the above-described configuration includes the optical adjustment layer 11 having a plurality of layers having different compositions between the transparent conductive layer 16, the transparent substrate 10, and the hard coat layer 20 sandwiching the transparent substrate 10. Of the optical adjustment layer 11, the second optical adjustment layer 14 containing silicon nitride has a large compressive stress. For this reason, after patterning the transparent conductive layer 16, when heated to form the extraction electrode, the undulation caused by the presence or absence of the transparent conductive layer 16 having a large compressive stress is sufficiently suppressed, and the sensing pattern The step at the boundary can be reduced. Such an action makes it difficult to visually recognize the sensing pattern. The step at the boundary of the sensing pattern can be, for example, 300 nm or less, and can be 200 nm or less.

  The thickness of the transparent conductor 100 may be 130 μm or less, or 115 μm or less. Such a thickness can sufficiently satisfy the required level of thinning. Since the transparent conductor 100 according to the present embodiment can reduce the step at the boundary portion of the sensing pattern, it is possible to make it difficult to visually recognize the sensing pattern even if the thickness is thus reduced. That is, the transparent conductor 100 is particularly useful in a technical field where thinning is required.

  The optical adjustment layer 11 includes the first optical adjustment layer 13 on the transparent substrate 10 side and the third optical adjustment layer 15 on the transparent conductive layer 16 side so as to sandwich the second optical adjustment layer 14. . The magnitude relationship of the refractive index of the optical adjustment layer 11 satisfies the above formula (1). That is, the refractive indexes n1 and n2 of the first optical adjustment layer 13 and the second optical adjustment layer 14 are larger than the refractive index n3 of the third optical adjustment layer. Thus, in the optical adjustment layer 11, the first optical adjustment layer 13 and the second optical adjustment layer 14 form a high refractive index layer, and the first optical adjustment layer 13 and the second optical adjustment layer 14. Further, the third optical adjustment layer on the transparent conductive layer 16 side is configured to form a low refractive index layer. By having such a layer structure, the total light transmittance of the transparent conductor 100 is improved.

  Among the optical adjustment layers 11 having a three-layer structure, the first optical adjustment layer 13 provided closest to the transparent substrate 10 can be produced by a coating method. For this reason, a thicker first optical adjustment layer can be easily manufactured. On the other hand, the second optical adjustment layer 14 can be produced by a vacuum film formation method. From the viewpoint of shortening the time required for producing the second optical adjustment layer 14, it is preferable that the second optical adjustment layer 14 is thin. Here, in general, the optical thickness can be expressed by [refractive index × thickness]. Therefore, in order to make the first optical adjustment layer 13 thick, it is necessary to lower the refractive index (n1) of the first optical adjustment layer 13. On the other hand, in order to make the second optical adjustment layer 14 thinner, it is necessary to increase the refractive index (n2) of the second optical adjustment layer 14. In the present embodiment, since the relationship between the refractive index (n1) of the first optical adjustment layer 13 and the refractive index (n2) of the second optical adjustment layer 14 is n2> n1, The layer structure of the optical adjustment layer 11 for increasing the light transmittance can be easily produced.

The total light transmittance of the transparent conductor 100 can be as high as 89% or more, for example. Further, the color coordinate b ^* value of the L ^* a ^* b ^* color system defined in JIS Z8729 of transmitted light can be set in the range of -1.0 to 2.0. The curl amount of the transparent conductor 100 can be set to −20 to 20 mm, for example, and can be set to −15 to 15 mm.

  FIG. 2 is a schematic cross-sectional view showing an enlarged part of a cross section of a touch panel 200 including a pair of sensor films. 3A and 3B are plan views of sensor films 100a and 100b using the transparent conductor 100 described above. The touch panel 200 includes a pair of sensor films 100 a and 100 b that are disposed to face each other via the optical glue 18. The touch panel 200 can calculate the touch position of the contact body as a coordinate position (horizontal position and vertical position) on a two-dimensional coordinate (XY coordinate) plane parallel to the panel board 70 serving as a screen. It is configured.

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

  The Y sensor film 100a for detecting the vertical position and the X sensor film 100b for detecting the horizontal position are constituted by the transparent conductor 100 described above. Specifically, the Y sensor film 100a has a sensor electrode 16a on the surface facing the X sensor film 100b. The sensor electrode 16 a is composed of a transparent conductive layer 16. As shown in FIG. 3A, a plurality of sensor electrodes 16a extend in the vertical direction (y direction) so that the touch position in the vertical direction (y direction) can be detected. The plurality of sensor electrodes 16a are arranged in parallel to each other along the vertical direction (y direction). One end of the sensor electrode 16a is connected to the electrode 80 on the driving IC side via a conductor line 50 formed of silver paste.

  The X sensor film 100b that detects the lateral position has a sensor electrode 16b on the surface facing the Y sensor film 100a. The sensor electrode 16 b is composed of the transparent conductive layer 16. As shown in FIG. 3B, a plurality of sensor electrodes 16b extend in the horizontal direction (x direction) so that the touch position in the horizontal direction (x direction) can be detected. The plurality of sensor electrodes 16b are arranged in parallel to each other along the horizontal direction (x direction). One end of the sensor electrode 16b is connected to the electrode 80 on the driving IC side via a conductor line 50 formed of silver paste.

  The Y sensor film 100a and the X sensor film 100b are overlapped via the optical glue 18 so that the sensor electrodes 16a and 16b are orthogonal to each other and face each other, thereby constituting the touch panel 200. The conductor line 50 and the electrode 80 are made of a conductive material such as metal (for example, Ag). The conductor line 50 and the electrode 80 are patterned by, for example, screen printing. The transparent substrate 10 also has a function as a protective film that covers the surface of the touch panel 200.

  The shape and number of the sensor electrodes 16a and 16b in the sensor films 100a and 100b are not limited to the forms shown in FIGS. For example, the detection accuracy of the touch position may be increased by increasing the number of sensor electrodes 16a and 16b.

  On the opposite side of the X sensor film 100b to the Y sensor film 100a side, a panel plate 70 is provided via a spacer 92. The spacer 92 can be provided at a position corresponding to the shape of the sensor electrodes 16a and 16b and a position surrounding the entire sensor electrodes 16a and 16b. The spacer 92 may be formed of a light-transmitting material, for example, PET (polyethylene terephthalate) resin. One end of the spacer 92 is bonded to the lower surface of the X sensor film 100b by an optical glue or an adhesive 90 having translucency such as acrylic or epoxy. The other end of the spacer 92 is bonded to the panel plate 70 of the display device with an adhesive 90. Thus, by arranging the X sensor film 100b and the panel plate 70 to face each other via the spacer 92, a gap S can be formed between the X sensor film 100b and the panel plate 70 of the display device. .

  A control unit (IC) is electrically connected to the electrode 80. When the Y sensor film 100a of the touch panel 200 is pressed by the contact body, the X sensor film 100b and the Y sensor film 100a are bent, and the sensor electrodes 16a and 16b approach the panel plate 70 of the display device. The control unit measures the capacitance change of each of the sensor electrodes 16a and 16b caused by the deformation, and determines the touch position of the contact body as a coordinate position based on the measurement result (intersection of the position in the X axis direction and the position in the Y axis direction). Can be calculated as In addition to the above, various known methods can be adopted as the sensor electrode driving method and the coordinate position calculation method.

  Since the touch panel 200 uses the transparent conductor 100 as the Y sensor film 100a and the X sensor film 100b, the touch panel 200 can be sufficiently thinned. Even if the thickness is reduced in this manner, the sensing patterns of the Y sensor film 100a and the X sensor film 100b can be made sufficiently difficult to recognize. In addition, it is not necessary to use the transparent conductor 100 for both the Y sensor film 100a and the X sensor film 100b, and either one may use another transparent conductor. Even with such a touch panel, the display can be made sufficiently clear.

  FIG. 4 is a schematic cross-sectional view showing another embodiment of the transparent conductor of the present invention. The transparent conductor 101 includes a warp suppressing layer 30 and a protective film 44 in this order on the second hard coat layer 24 from the second hard coat layer 24 side. It differs from the transparent conductor 100 in that a protective film 42 is provided on the side opposite to the optical adjustment layer 11 side. Other configurations are the same as those of the transparent conductor 100.

  The warpage suppressing layer 30 is formed on the second hard coat layer 24, and, like the second optical adjustment layer 14, a vacuum deposition method such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. It can be produced by a film method. Among these, the sputtering method is preferable in that the film forming chamber can be reduced in size. The sputtering method is particularly preferable when there are a plurality of layers to be formed.

  The component contained in the warp suppressing layer 30 is not particularly limited, and may include, for example, silicon oxide, silicon nitride, or both silicon nitride and silicon oxide. The target material for producing the warp suppressing layer 30 may be the same as that of the second optical adjustment layer 14 or the third optical adjustment layer 15. As a result, an increase in production cost associated with the target changing operation can be suppressed. By providing the warp suppressing layer 30, it is possible to more sufficiently suppress the occurrence of warping of the transparent conductor 101 and reduce the curl amount. The thickness of the warp suppressing layer 30 is, for example, 5 to 40 nm.

(Protective film 40)
The protective film 40 can improve the mechanical strength of the transparent conductor 101 in addition to suppressing the warp of the transparent conductor 101. The protective film 40 can be provided on the transparent conductive layer 16 and / or on the warpage suppressing layer 30. When the warp suppressing layer 30 is not provided, the protective film 44 may be provided on the second hard coat layer 24. In the case of the projected electrostatic capacity method, the transparent conductive layer 16 is subjected to a sensing pattern process, and thus it is necessary to peel off the protective film 42 when performing this process. For this reason, according to the use of the transparent conductor 101, you may provide the protective film 40 only in the 2nd hard-coat layer 24 side.

  The protective film 40 has a function of suppressing warpage when the transparent conductive layer 16 is crystallized. For this reason, it is preferable to have heat resistance enough to withstand the temperature of the crystallization treatment. As the protective film having heat resistance, for example, Sankyury (trade name) manufactured by Sanei Kaken Co., Ltd., TP2316 (trade name) manufactured by Cosmotech, etc. can be used.

  The above-described transparent conductors 100 and 101 can be suitably used for touch panels. However, the application is not limited to the touch panel. For example, the transparent conductive layer is processed into a predetermined shape, and the portion having the transparent conductive layer (conductive portion) and the portion having no transparent conductive layer (non-conductive) In various display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence panel (organic EL, inorganic EL), electrochromic element, and electronic paper, for transparent electrodes, It can be used for antistatic and electromagnetic shielding. It can also be used as an antenna.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, although the hard coat layer 20 is provided in the above-described embodiment, the hard coat layer 20 may not be provided. Moreover, you may provide arbitrary layers in arbitrary positions other than the above-mentioned layer in the transparent conductor of this invention in the range which does not impair the function. The touch panel is not limited to the grid type including the pair of sensor films as described above, and may be a single plate switch type including only one sensor film.

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

[Example 1]
A transparent conductor 100 as shown in FIG. 1 was produced. The transparent conductor 100 includes a second hard coat layer 24, a transparent substrate 10, a first hard coat layer 22, a first optical adjustment layer 13, a second optical adjustment layer 14, and a third optical adjustment layer 15. , And the transparent conductive layer 16 has a laminated structure laminated in this order. The transparent conductor 100 was produced as follows.

(Transparent substrate 10)
A polyethylene terephthalate film having a thickness of 50 μm (manufactured by Teijin DuPont Films, product number: KEL-86w) was prepared. This PET film was used as the transparent substrate 10. The PET film had a total light transmittance of 91%, a haze of 1%, and a refractive index of 1.52 at λ = 633 nm.

(Preparation of paint for producing first hard coat layer 22 and second hard coat layer 24)
The following raw materials were prepared.
Reactive group-decorated colloidal silica (dispersion medium: propylene glycol monomethyl ether acetate, nonvolatile content: 40% by weight): 100 parts by weight Dipentaerythritol hexaacrylate: 48 parts by weight 1,6-hexanediol diacrylate: 12 parts by weight Parts / photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone): 2.5 parts by weight

  The above-mentioned raw materials were diluted with a solvent (propylene glycol monomethyl ether (PGMA)) and mixed, and each component was dispersed in the solvent. As a result, a paint having a nonvolatile content (NV) of 25.5% by weight was prepared. The paint thus obtained was used as a paint for producing the first hard coat layer 22 and the second hard coat layer 24.

(Paint for preparing first optical adjustment layer 13)
Diluting TYZ62 (trade name, manufactured by Toyo Ink Co., Ltd., refractive index: 1.62) containing zirconium oxide (ZrO ₂ ) with propylene glycol monomethyl ether (PGMA) as a solvent, nonvolatile content (NV) Prepared 2.6 wt% paint. The obtained paint was used as a paint for preparing the first optical adjustment layer.

(Preparation of transparent conductor 100)
<Preparation of the first hard coat layer 22>
On one side of the PET base material fed out from the roll, a coating for preparing the first hard coat layer 22 was applied so that the film thickness after drying was 1.0 μm to prepare a coating film. After removing the solvent in the coating film in a drying oven set at 80 ° C., the coating film was cured by irradiating with an ultraviolet ray having an integrated light amount of 400 mJ / cm ² using a UV processing apparatus. Thus, the 1st hard-coat layer 22 was produced on the one side of PET film. After producing the first hard coat layer 22, the PET film on which the first hard coat layer 22 was produced was wound into a roll. The refractive index of the first hard coat layer 22 was 1.50.

<Preparation of Second Hard Coat Layer 24>
The PET film having the first hard coat layer 22 formed on one side is drawn out from the roll, and the second hard coat layer 24 is formed on the other side of the PET film so that the film thickness after drying is 1.0 μm. The coating film for preparation was apply | coated and the coating film was produced. After removing the solvent in the coating film in a drying oven set at 80 ° C., the coating film was cured by irradiating with an ultraviolet ray having an integrated light amount of 400 mJ / cm ² using a UV processing apparatus. In this way, a second hard coat layer 24 was produced on the other side of the PET film. After producing the 2nd hard coat layer 24, the PET film in which the 1st hard coat layer 22 and the 2nd hard coat layer 24 were produced was wound up in roll shape. The refractive index of the second hard coat layer 24 was 1.50.

<Preparation of the first optical adjustment layer 13>
The PET film on which the first hard coat layer 22 and the second hard coat layer 24 are produced is fed out from the roll, and the coating material for producing the first optical adjustment layer 13 is rolled on the first hard coat layer 22. The coating film was produced by coating by the to-roll method. After removing the solvent in the coating film in a drying oven set at 80 ° C., the coating film was cured by irradiating with an ultraviolet ray having an integrated light amount of 400 mJ / cm ² using a UV processing apparatus. In this way, the first optical adjustment layer 13 was produced on the first hard coat layer 22. The refractive index (n1) of the first optical adjustment layer 13 was 1.62.

<Preparation of Second Optical Adjustment Layer 14>
On the 1st optical adjustment layer 13, the 2nd optical adjustment layer 14 was produced using sputtering method. Specifically, a second optical adjustment layer 14 made of silicon nitride is formed by forming a film in a mixed atmosphere of 80% by volume of argon gas and 20% by volume of nitrogen gas using a silicon target doped with boron. Produced. The refractive index (n2) of the second optical adjustment layer 14 was 1.90.

<Preparation of Third Optical Adjustment Layer 15>
On the 2nd optical adjustment layer 14, the 3rd optical adjustment layer 15 was produced using sputtering method. Specifically, the third optical adjustment layer 15 made of silicon oxide was produced in a mixed atmosphere consisting of 95% by volume of argon gas and 15% by volume of oxygen gas, using a silicon target doped with boron. The refractive index (n3) of the third optical adjustment layer 15 was 1.46.

<Preparation of transparent conductive layer 16>
A transparent conductive layer 16 was produced on the third optical adjustment layer 15 by sputtering. Specifically, using a target obtained by adding 5% by weight of tin oxide to indium oxide, a film was formed in a mixed atmosphere consisting of 98% by volume of argon gas and 2% by volume of oxygen gas. A transparent conductive layer 16 made of the composite oxide was prepared. Thereafter, the laminate was heated in an oven at 140 ° C. for 90 minutes to produce a transparent conductor 100. The refractive index of the transparent conductive layer 16 was 2.05.

(Measurement of film thickness)
A cross section of the transparent conductor 100 was obtained by a focused ion beam apparatus (FIB, Focused Ion Beam). The cross section was observed using a transmission electron microscope (TEM), and the thickness of each layer was measured. The measurement results are shown in Table 1.

(Measurement of refractive index)
For the refractive indexes of the PET film (transparent substrate 10), the first hard coat layer 22, and the second hard coat layer 24, a reflection spectral film thickness meter (trade name: FE-3000, manufactured by Otsuka Electronics Co., Ltd.) is used. And measured. On the other hand, the refractive indexes of the first optical adjustment layer 13, the second optical adjustment layer 14, the third optical adjustment layer 15, and the transparent conductive layer 16 were measured by separately preparing a refractive index measurement film. Specifically, it is applied onto a silicon wafer to form a film, and using an ellipsometer (trade name: DHA-OLX, manufactured by Mizoji Optical Co., Ltd.), the film (layer) at λ = 633 nm at 20 ° C. The refractive index was measured.

(Measurement of curl amount)
In order to quantitatively evaluate the warpage generated in the transparent conductor, the curl amount was measured by the following procedure. The produced transparent conductor 100 was cut into a size of 200 mm × 200 mm along the MD direction and the TD direction. Then, with the transparent conductive layer 16 facing upward, a heat treatment was performed at 140 ° C. for 90 minutes using an oven. After the heat treatment, as shown in FIG. 5, the transparent conductor 100 is placed on the flat surface 95 so that the concave surface is on the upper side, and the distances a, b, c between the flat surface 95 and the vertex of the transparent conductor 100 are d was measured and the maximum value thereof was defined as the curl amount. The results are as shown in Table 1. The curl amount was defined as + (plus) when measured with the second hard coat layer 24 side down, and was represented as-(minus) when measured with the transparent conductive layer 16 side facing down.

(Measurement of total light transmittance and color tone)
The total light transmittance of the transparent conductor 100 was evaluated using a haze meter (model number: NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). The results are as shown in Table 1. Further, a part of the transparent conductive layer 16 of the transparent conductor 100 was covered with a mask, and the other part of the transparent conductive layer 16 was removed using an etching solution. L ^* a ^* b ^* table of transmitted light using spectral color difference meter CM-5 (trade name, manufactured by Konica Minolta Co., Ltd.) for the portion (conductive portion) with and without transparent conductive layer 16 (non-conductive portion). The color coordinate b ^* value of the color system was measured. The difference between the color coordinate b ^* values was calculated. The results are as shown in Table 1.

(Measurement of the step at the boundary)
A part of the transparent conductive layer 16 in the transparent conductor 100 was covered with a mask, and the other part of the transparent conductive layer 16 was removed using an etching solution. This formed a sensing pattern. As shown in FIG. 6, a glass substrate 19 having a thickness of 0.6 mm was pasted on the third optical adjustment layer 15 and the transparent conductive layer 16 via the optical glue 18. Thus, the evaluation sample shown in FIG. 6 was produced. The level | step difference which generate | occur | produced in the boundary part 16A of a sensing pattern evaluated using the contact needle type | formula surface shape measuring device (brand name: Dektak 3, Veeco). The results are as shown in Table 1.

[Examples 2 to 5, Comparative Example 1]
Transparent conductors of Examples 2 to 5 and Comparative Example 1 were produced in the same manner as Example 1 except that the thickness of the third optical adjustment layer 15 was changed as shown in Table 1. In Comparative Example 1, the third optical adjustment layer 15 was not produced. In the same manner as in Example 1, each layer and the transparent conductor were evaluated. The evaluation results are shown in Table 1.

In any of the transparent conductors of Examples 1 to 5, the step at the boundary was sufficiently small, and the absolute value of the curl amount was sufficiently small. Furthermore, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0. On the other hand, the total light transmittance of the transparent conductor of Comparative Example 1 was less than 89%.

[Examples 6 to 10, Comparative Examples 2 to 3]
Except having changed the thickness of the 1st optical adjustment layer 13 and the 2nd optical adjustment layer 14 as shown in Table 2, it is the same as that of Example 1, and Example 6-10 and Comparative Examples 2-3. A transparent conductor was produced. In Comparative Example 2, the first optical adjustment layer was not produced, and in Comparative Example 3, the second optical adjustment layer was not produced. In the same manner as in Example 1, each layer and the transparent conductor were evaluated. The evaluation results are shown in Table 2.

It was confirmed that all of the transparent conductors of Examples 6 to 10 had a sufficiently small step at the boundary portion and the sensing pattern was difficult to see. Also, the absolute value of the curl amount was sufficiently small. Furthermore, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0. On the other hand, the transparent conductor of Comparative Example 2 has a problem that the step at the boundary is 300 nm or more and the sensing pattern is easily recognized. The transparent conductor of Comparative Example 3 had a large curl amount.

[Examples 11 to 14]
Except that the thicknesses of the first optical adjustment layer 13, the second optical adjustment layer 14, and the third optical adjustment layer 15 were changed as shown in Table 3, the same procedures as in Example 1 were repeated. 12 transparent conductors were produced. Moreover, the transparent conductors of Examples 13 and 14 were produced in the same manner as in Example 1 except that the thickness of the transparent conductive layer was changed as shown in Table 3. Then, in the same manner as in Example 1, each layer and the transparent conductor were evaluated. The evaluation results are shown in Table 3.

In all of the transparent conductors of Examples 11 to 14, the step at the boundary portion was sufficiently small, and the absolute value of the curl amount was sufficiently small. Furthermore, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0.

[Examples 15 to 17, Comparative Example 4]
Transparent conductors of Examples 15 to 17 and Comparative Example 4 were produced in the same manner as in Example 1 except that the production method of the second optical adjustment layer 14 was changed to the following procedure. In Example 15, a silicon target doped with boron was used to form a film in a mixed atmosphere composed of 80% by volume of argon gas, 18% by volume of nitrogen gas, and 2% by volume of oxygen gas. A second optical adjustment layer 14 comprising: The refractive index (n2) of the second optical adjustment layer 14 was 1.79 at λ = 633 nm. The composition was Si ₃ N ₄ : SiO ₂ = 80: 20 in terms of molar ratio when silicon nitride was Si ₃ N ₄ and silicon oxide was SiO ₂ .

In Example 16, a silicon target doped with boron was used to form a film in a mixed atmosphere composed of 80% by volume of argon gas, 15% by volume of nitrogen gas, and 5% by volume of oxygen gas, and oxidized with silicon nitride. A second optical adjustment layer 14 made of silicon was produced. The refractive index (n2) of the second optical adjustment layer 14 was 1.70 at λ = 633 nm. The composition was Si ₃ N ₄ : SiO ₂ = 60: 40 in terms of molar ratio, when silicon nitride was Si ₃ N ₄ and silicon oxide was SiO ₂ .

In Example 17, a silicon target doped with boron was used to form a film in a mixed atmosphere composed of 80% by volume of argon gas, 12% by volume of nitrogen gas, and 8% by volume of oxygen gas, and oxidized with silicon nitride. A second optical adjustment layer 14 made of silicon was produced. The refractive index (n2) of the second optical adjustment layer 14 was 1.64 at λ = 633 nm. The composition was Si ₃ N ₄ : SiO ₂ = 40: 60 in terms of molar ratio when silicon nitride was Si ₃ N ₄ and silicon oxide was SiO ₂ .

In Comparative Example 4, a silicon target doped with boron was used to form a film in a mixed atmosphere composed of 80% by volume of argon gas, 10% by volume of nitrogen gas, and 10% by volume of oxygen gas, and oxidized with silicon nitride. A second optical adjustment layer 14 made of silicon was produced. The refractive index (n2) of the second optical adjustment layer 14 was 1.55 at λ = 633 nm. The composition was Si ₃ N ₄ : SiO ₂ = 20: 80 in terms of a molar ratio when silicon nitride was Si ₃ N ₄ and silicon oxide was SiO ₂ . In the same manner as in Example 1, each layer of Examples 15 to 17 and Comparative Example 4 and the transparent conductor were evaluated. The evaluation results are shown in Table 4.

In all of the transparent conductors of Examples 15 to 17, the step at the boundary portion was sufficiently small, and the absolute value of the curl amount was also sufficiently small. Furthermore, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0. On the other hand, the transparent conductor of Comparative Example 4 that does not satisfy the formula (1) has a small absolute value of the curl amount, but the boundary step exceeds 300 nm, and the sensing pattern is easy to recognize.

[Examples 18 to 21, Comparative Examples 5 to 6]
Examples 18 to 21 and Comparative Examples 5 to 6 were the same as Example 1 except that the thickness of the transparent substrate 10 and the thickness of the first hard coat layer 22 were changed as shown in Table 5. A transparent conductor was prepared. In Comparative Examples 5 to 6, the second optical adjustment layer was not produced. In the same manner as in Example 1, each layer and transparent conductor in each Example and each Comparative Example were evaluated. The evaluation results are shown in Table 5.

In all of the transparent conductors of Examples 18 to 21, the step at the boundary portion was sufficiently small, and the absolute value of the curl amount was also sufficiently small. Furthermore, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0. On the other hand, in the transparent conductor of Comparative Example 5, the step at the boundary portion exceeded 300 nm, and the sensing pattern was easy to recognize.

[Examples 22 to 24]
The thicknesses of the first optical adjustment layer 13, the second optical adjustment layer 14, and the third optical adjustment layer 15 were changed as shown in Table 6. Further, using a silicon target doped with boron, a film is formed on the second hard coat layer 24 in a mixed atmosphere composed of 80% by volume of argon gas and 20% by volume of nitrogen gas. A warpage suppressing layer made of silicon nitride and having a thickness of 10 nm was formed on the side opposite to the side. A transparent conductor of Example 22 was produced in the same manner as Example 1 except for these points. And it carried out similarly to Example 1, and evaluated each layer and transparent conductor of each Example. The evaluation results are shown in Table 6.

  In Example 23, a silicon target doped with boron was used to form on the second hard coat layer 24 in a mixed atmosphere composed of 80% by volume of argon gas, 15% by volume of nitrogen gas, and 5% by volume of oxygen gas. A warpage suppressing layer having a thickness of 10 nm made of silicon nitride and silicon oxide was produced on the side opposite to the transparent substrate 10 side. A transparent conductor of Example 23 was made in the same manner as Example 22 except for this point. And it carried out similarly to Example 1, and evaluated each layer and transparent conductor of each Example. The evaluation results are shown in Table 6.

  In Example 24, a silicon target doped with boron was used to form a film on the second hard coat layer 24 in a mixed atmosphere consisting of 85% by volume of argon gas and 15% by volume of oxygen gas. A warpage suppressing layer made of silicon oxide and having a thickness of 10 nm was produced on the side opposite to the material 10 side. A transparent conductor of Example 24 was made in the same manner as Example 22 except for this point. And it carried out similarly to Example 1, and evaluated each layer and transparent conductor of each Example. The evaluation results are shown in Table 6.

In any of the transparent conductors of Examples 22 to 24, the step at the boundary was sufficiently small, and the curl amount was in the range of −5 to −3 mm. The absolute value of the curl amount was smaller in Examples 22 to 24 than in Example 9 having the same configuration. Further, the total light transmittance was as high as 89% or more, and the difference between the transmitted light b ^* values was as small as -2.0 to 2.0. From this, it was confirmed that the curl amount can also be reduced by producing a warp suppressing layer on the second hard coat layer 24.

  According to the present invention, it is possible to provide a transparent conductor that has a high total light transmittance and is difficult to visually recognize a sensing pattern even if the transparent conductor is thinned. Further, by using this transparent conductor, it is possible to provide a touch panel that has a clear display and is difficult to visually recognize the sensing pattern.

  DESCRIPTION OF SYMBOLS 10 ... Transparent base material, 11 ... Optical adjustment layer, 22 ... 1st hard-coat layer, 13 ... 1st optical adjustment layer, 14 ... 2nd optical adjustment layer, 15 ... 3rd optical adjustment layer, 16 ... Transparent conductive layer, 16A ... boundary, 16a, 16b ... sensor electrode, 24 ... second hard coat layer, 19 ... glass substrate, 20 ... hard coat layer, 30 ... warpage suppression layer, 40, 42, 44 ... protective film , 50 ... conductor line, 70 ... panel board, 80 ... electrode, 90 ... adhesive, 92 ... spacer, 100, 101 ... transparent conductor, 100a ... sensor film for Y, 100b ... sensor film for X, 200 ... touch panel.

Claims (9)

A transparent conductor comprising a transparent substrate, a transparent conductive layer, and an optical adjustment layer between the transparent substrate and the transparent conductive layer,
The optical adjustment layer has a first optical adjustment layer, a second optical adjustment layer, and a third optical adjustment layer from the transparent substrate side,
The first optical adjustment layer contains a cured resin,
The second optical adjustment layer contains silicon nitride, or silicon nitride and silicon oxide,
The third optical adjustment layer contains silicon oxide,
The thickness of the first optical adjustment layer is 10 to 80 nm,
Said first optical adjustment layer, the refractive index of the second optical adjustment layer and the third optical adjustment layer, respectively, when the n1, n2 and n3, and meets the following formula (1),
The transparent conductor whose n1 is 1.55-1.80 .
n2>n1> n3 (1)   2. The transparent conductor according to claim 1, wherein in the second optical adjustment layer, a ratio of the silicon nitride to a total of the silicon nitride and the silicon oxide is 40 mol% or more. Thickness before Symbol second optical adjustment layer is 1 to 25 nm, the transparent conductor according to claim 1 or 2.   The transparent conductor according to claim 1, wherein the third optical adjustment layer has a thickness of 1 to 40 nm.   The transparent conductor as described in any one of Claims 1-4 whose thickness is 130 micrometers or less.   The transparent conductor as described in any one of Claims 1-5 which has a curvature suppression layer containing silicon nitride or silicon nitride and silicon oxide on the opposite side to the said optical adjustment layer side of the said transparent base material.   Either of the said transparent base material has a protective film on the opposite side to the said optical adjustment layer side, and / or the said 3rd optical adjustment layer side of the said transparent conductive layer, The any one of Claims 1-6 The transparent conductor according to one item. The transparent conductor according to any one of claims 1 to 7, wherein n2 is 1.62 to 2.30 and n3 is 1.35 to 1.55. It is a touch panel in which a panel board and a sensor film are arranged to face each other,
The touch panel whose said sensor film is a transparent conductor as described in any one of Claims 1-8 .

Images