JP2008181838A - Transparent conductive laminated body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent conductive laminated body through which the hue of transmitted light is not yellow but neutral, since there is such a problem that an ITO absorbs the light of a short wavelength range smaller than 450 nm depending on its characteristics and the hue of transmitted light contains a tinge of yellow as a result. <P>SOLUTION: A transparent conductive substrate 1 is formed on the surface of one side of a transparent substrate 2 by laminating a high refractive index material 3 and a low refractive index material 4 compared with a refractive index of the substrate in this order and forming a transparent conductive film 5 for an outermost layer. The transparent conductive laminated body is formed in a way that b* of the transmitted light is smaller than 2 in a color system represented by L*a*b* at 2 degrees of a perspective angle of a D65 light source. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transparent conductive laminate, and more particularly to a transparent conductive laminate having a function of correcting a transmitted color by laminating thin films having different refractive indexes.

  An example of an antireflection laminate in which three or more thin films with a transparent conductive film formed on the outermost surface are laminated is one in which the refractive index of each layer is limited as described in Patent Document 1, and a touch panel as in Patent Document 2 An antireflection laminate having a transparent conductive film limited to 25 nm or less for use is known. Furthermore, a laminate in which the material and film thickness of each layer is limited as in Patent Document 3 is also known.

The above prior art documents are shown below.
WO00 / 63924 JP-A-11-53114 Japanese Patent No. 2509215

  Indium tin oxide (ITO), which is most commonly used as a transparent electrode, is classified as a high-refractive index material with a higher refractive index than general glass and plastic substrates. If ITO is formed on the substrate, the transmittance is lowered (the reflectance is increased). Therefore, by forming a plurality of high-refractive index materials and low-refractive index materials at appropriate thicknesses between the substrate and the ITO film, it is possible to increase the transmittance (reduce the reflectivity).

  However, in general, when trying to increase the transmittance in the visible light region, an optical film configuration that increases the transmittance near the wavelength of 550 nm, which has the highest visibility, is adopted. Since there is absorption in a short wavelength region of 450 nm or less, there is a problem that the transmitted color becomes yellow.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transparent conductive laminate having a neutral color with no yellowish transmission color.

As a means to solve the problem,
In the first aspect of the present invention, a high refractive index material and a low refractive index material are laminated in this order on one surface of a transparent substrate in comparison with the refractive index of the substrate, and a transparent conductive film is formed on the outermost layer. In the transparent conductive substrate, b * is 2 or less when the transmitted light is expressed by the L * a * b * color system of the D65 light source 2 ° field of view. is there.

  According to the second aspect of the present invention, when the transmitted light of a single substrate is expressed in the L * a * b * color system of the D65 light source 2 ° field of view, b * is 1 or less on one surface of the transparent substrate. In a transparent conductive substrate in which a high refractive index material and a low refractive index material are laminated in this order and a transparent conductive film is formed on the outermost layer, b * of the transmitted light is 1 or less. This is a transparent conductive laminate.

The invention according to claim 3 is the transparent conductive laminate according to claim 1 or 2, wherein the surface resistance value is in the range of 20Ω / □ to 150Ω / □. It is.

  According to a fourth aspect of the present invention, in the transparent conductive laminate according to any one of the first to third aspects, the optical film thickness of the first high refractive index material is nd <λ / 8 (400 nm <λ < 800 nm), which is a transparent conductive laminate.

  The invention according to claim 5 is the transparent conductive laminate according to any one of claims 1 to 4, wherein the substrate is plastic.

The invention according to claim 6 is the transparent conductive laminate according to claim 5, wherein the water vapor permeability of the laminate after the patterning step of the transparent conductive film is 40 ° C. and 90% Rh. In this condition, the transparent conductive laminate is 0.5 g / m ² · day or less.

  The invention described in claim 7 is a display device using the transparent conductive laminate according to any one of claims 1 to 6.

  A transparent conductive substrate in which a high refractive index material and a low refractive index material are laminated in this order on one surface of a transparent substrate in this order, and a transparent conductive film is formed on the outermost layer. A transparent conductive laminate having a neutral color with no visual yellowness by forming a film structure in which b * is 2 or less when light is expressed in the L * a * b * color system. It becomes.

  Furthermore, by using a film configuration in which b * is 1 or less, there is an effect of reducing the possibility of yellowness being observed even when the hue changes due to slight variations in the refractive index and film thickness within the film formation surface. .

  In general, the lower the resistance of the transparent conductive film, the thicker the film thickness, and the more yellow the color becomes. When forming a transparent conductive film lower than the resistance value used in a digital touch panel, for example, 150 Ω / □ or less as used for an inorganic EL substrate, at least two layers having a high refractive index and a low refractive index are formed. It becomes possible to suppress yellowishness by forming between and.

  In general, when the antireflection function is provided, the optical film thickness of the first high refractive index material is nd> λ / 8 (400 nm <λ <800 nm) in order to reduce the reflectance near the wavelength of 550 nm (increase the transmittance). However, by setting nd <λ / 8, there is an effect of increasing the transmittance in a short wavelength region and consequently suppressing yellowness. In addition, the manufacturing cost can be reduced by reducing the film thickness.

  By making the substrate a flexible material such as plastic, an electrode substrate that is not damaged by an impact is obtained. Further, when forming a thin film, mass production can be continuously performed in large quantities by the roll-to-roll method, and production cost can be suppressed.

Plastic substrates usually have poor gas shielding properties such as water vapor and cause deterioration of electronic device materials. However, a transparent conductive film is formed by using a thin film having barrier performance on the high refractive index material and / or low refractive index material on the substrate. The water vapor permeability of the laminate after the layer etching step is 40 ° C. and 90% Rh. In the condition of 0.5 g / m ² · day or less, deterioration of the electronic device material can be suppressed and the device life can be extended.

By using the transparent conductive laminate of the present invention for a display device, display with good color reproducibility becomes possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In the schematic diagram of FIG. 1, a high refractive index material (3) and a low refractive index material (4) are laminated in this order on one surface of a transparent substrate (2) in comparison with the refractive index of the substrate. A transparent conductive laminate (2) having a transparent conductive film (5) formed thereon.

  Glass or plastic film is used for the transparent substrate (2) used in the present invention. The plastic film is not particularly limited as long as it has sufficient strength in the film forming process and in the subsequent process and has good surface smoothness. For example, polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polycarbonate film , Polyethersulfone film, polysulfone film, polyarylate film, cyclic polyolefin film, polyimide and the like. In particular, when applied to a display device front plate, polycarbonate and polyethersulfone having excellent transparency and heat resistance are preferably used. The thickness is about 10 to 200 μm in consideration of the thinning of the member and the flexibility of the base material. Various well-known additives and stabilizers such as an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, a lubricant, and an easy-adhesive agent may be used on the surface of these substrates. In order to improve the adhesion with the barrier layer, corona treatment, low-temperature plasma treatment, ion bombardment treatment, chemical treatment, or the like may be performed as pretreatment.

  The high-refractive index material (3) and the low-refractive index material (4) are not particularly limited as long as they satisfy the relationship of the refractive index regardless of whether they are organic materials or inorganic materials. Materials such as sulfides, fluorides and nitrides can be used. The thin film made of the inorganic compound has a different refractive index depending on the material, and the optical characteristics can be adjusted by laminating a plurality of ceramic thin films having different refractive indexes with a specific film thickness.

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

  As a method for producing a high refractive index material and a low refractive index material in the present invention, any film forming method may be used as long as the film thickness can be controlled, and among these, a dry method is excellent for producing a thin film. For this, a vacuum vapor deposition method, a physical vapor deposition method such as sputtering, or a chemical vapor deposition method such as a CVD method can be used.

  Examples of the transparent conductive film (5) include indium oxide, zinc oxide, and tin oxide, or two or three kinds of mixed oxides thereof, and those added with other additives. Various materials can be used depending on the purpose and application, and are not particularly limited.

  Examples of the material having barrier performance include silicon and aluminum oxides and nitrides, and examples of the high refractive index material include indium oxide, but are not particularly limited.

  As an etching process, a method using photolithography is common. Since an alkali or acid solution is used in the pattern development and etching processes, the thin film having the barrier performance must have sufficient resistance to them.

  Next, the present invention will be described in detail with specific examples.

<Example 1>
On a polyethylene naphthalate substrate, 42 nm of titanium oxide and 19 nm of silicon oxide were laminated in this order by vacuum film formation, and 115 nm of indium tin oxide (ITO) was laminated thereon to produce a transparent conductive laminate. Each film thickness is an optical film thickness nd.

The produced transparent conductive laminate had a surface resistance value of 95Ω / □, and transmitted light was b * = 0.2 in a 2 ° field of view of a D65 light source. Thus, a transparent transparent conductive laminate having a transparent color was obtained. Moreover, when the water vapor transmission rate was measured after electrode patterning, it was 0.1 g / m ² · day. When this transparent conductive laminate was used as an inorganic EL substrate, a display with good color reproducibility was obtained, and the device was heated to 60 ° C. and 90% Rh. When the durability test was conducted for 1000 hours under the above conditions, no deterioration was observed.
<Example 2>
Titanium oxide 42nm and silicon oxide 19nm are laminated in this order by vacuum film formation on a polycarbonate substrate of b * = 0.3 with 2 ° field of view of D65 light source, and indium tin oxide (ITO) is laminated on it in this order. A transparent conductive laminate was produced by laminating 115 nm. Each film thickness is an optical film thickness nd.

The produced transparent conductive laminate had a surface resistance value of 95Ω / □, and the transmitted light was b * = − 0.9 in a 2 ° field of view of the D65 light source, and a transparent transparent conductive laminate having a neutral transmission color was obtained. When this transparent conductive laminate was used as a substrate for electronic paper, a display body with good color reproducibility was obtained.
<Comparative Example 1>
As shown in FIG. 2, an indium tin oxide (ITO) film having a thickness of 115 nm was formed on a polycarbonate substrate by vacuum film formation. The film thickness is the optical film thickness nd.

The surface resistance value of the produced transparent conductive laminate was 95Ω / □, the transmitted light was b * = 3.1 in a 2 ° field of view of the D65 light source, and the transmitted color was felt yellow from brown.
<Comparative example 2>
By vacuum film formation on a polycarbonate substrate, titanium oxide 110 nm (nd> λ / 8, 400 nm <λ <800 nm) and silicon oxide 19 nm were stacked in this order, and indium tin oxide (ITO) was stacked 115 nm thereon. Each film thickness is an optical film thickness nd.

  The produced transparent conductive laminate had a surface resistance value of 95Ω / □, a luminous reflectance Y of 3.3, and low reflection was realized, but the transmitted light was b * = 12 in the D65 light source 2 ° field of view, The yellow color from tea was strongly felt in the transmitted color.

It is sectional drawing of the transparent conductive laminated body which laminated | stacked the high refractive index material, the low refractive index material, and the transparent conductive film in order on one side of the transparent base material which concerns on this invention. As a comparative example, it is sectional drawing of the transparent conductive laminated body in which the transparent conductive film was formed in the single side | surface of a transparent base material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent conductive laminated body 2 ... Transparent base material 3 ... High refractive index material layer 4 ... Low refractive index material layer 5 ... Transparent conductive film layer

Claims (7)

  A transparent conductive substrate in which a high refractive index material and a low refractive index material are laminated in this order on one surface of a transparent substrate in this order, and a transparent conductive film is formed on the outermost layer. A transparent conductive laminate, wherein b * is 2 or less when light is expressed in an L * a * b * color system with a 2 ° field of view of a D65 light source.   High refraction compared to the refractive index of the substrate on one side of the transparent substrate where b * is 1 or less when the transmitted light of the substrate alone is expressed in the L * a * b * color system of the D65 light source 2 ° field of view. The transparent conductive laminate is characterized in that, in the transparent conductive substrate in which the refractive index material and the low refractive index material are laminated in this order and the transparent conductive film is formed on the outermost layer, b * of the transmitted light is 1 or less. body.   The transparent conductive laminate according to claim 1 or 2, wherein the surface resistance value is in a range of 20Ω / □ to 150Ω / □.   4. The transparent conductive laminate according to claim 1, wherein the optical film thickness of the first high refractive index material is nd <λ / 8 (400 nm <λ <800 nm). , Transparent conductive laminate.   The transparent conductive laminate according to any one of claims 1 to 4, wherein the substrate is a plastic. The transparent conductive laminate according to claim 5, wherein the water vapor permeability of the laminate after patterning the transparent conductive film is 40 ° C. and 90% Rh. The transparent conductive laminate is 0.5 g / m ² · day or less under the above conditions.   A display device using the transparent conductive laminate according to claim 1.

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