JPH08201791A - Transparent electrode substrate - Google Patents

Abstract

PURPOSE: To provide a transparent electrode substrate using a plastic film as a substrate having excellent durability and display performance for a display panel, etc. CONSTITUTION: A gas barrier layer is formed with an anchor coat layer interposed on one or both surfaces of a plastic film, and further, a protective layer is formed on one or both surfaces of the laminated body to obtain a laminated substrate. Then a transparent conductive layer is formed on one or both surfaces of the laminated substrate to obtain a transparent electrode substrate. The transparent conductive layer consists of amorphous indium oxide having 95/5 to 85/15 weight ratio of indium/tin and 20 to 200nm film thickness. The plastic film shows optical isotropy with <=20nm retardation and within ±15 deg. variance of the axis of logging has 70 to 200μm thickness. The surface roughness of the laminated substrate where the transparent conductive layer is to be formed is <=4Onm center line average roughness Ra.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to gas permeation resistance of oxygen, nitrogen, carbon dioxide, etc., water vapor permeation resistance, smoothness, flatness,
A liquid crystal that has good optical characteristics, excellent display quality when used in liquid crystal display panels, etc., and that does not deteriorate its display quality even when affected by mechanical, thermal and solvent effects. The present invention relates to a transparent electrode substrate suitable for an electrode of a display / illumination panel such as a display panel, and to a transparent electrode substrate that can be used as an electrode for a photoconductive photoconductor, a surface heating element, an electrode for organic electroluminescence, etc., in addition to a liquid crystal display device. .

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have become lighter and thinner.
In addition to the demand for larger size, there are high demands such as long-term reliability, freedom of shape, and curved surface display. In particular, as the use of portable and mobile devices such as pagers (pagers), mobile phones, electronic organizers, and pen input devices becomes widespread, the conventional thick, heavy, and fragile glass substrates are replaced by plastics. A liquid crystal panel or the like using a transparent electrode having a substrate as a substrate has been studied, and some have begun to put it into practical use.

Such a plastic substrate is disclosed in JP-A-56
It has already been described in Japanese Patent Publication No. 130010 and the like and is publicly known.

[0004]

The transparent electrode substrate of the plastic film substrate is, compared with that of the glass substrate,
It is light and thin, can be freely shaped, and meets the requirements for curved surface display, but has the drawback of being inferior in gas permeation resistance, water vapor permeation resistance, smoothness, flatness, optical characteristics, long-term reliability, etc. There is.

When a transparent electrode substrate made of a plastic film having poor gas permeation resistance and water vapor permeation resistance is used, even if the conductive layer itself has high gas permeation resistance and water vapor permeation resistance, it is actually used as a liquid crystal cell. In this case, since the conductive layer is etched and patterned, a part without the conductive layer is generated, air and water vapor permeate from this part, bubbles are generated in the liquid crystal part, it becomes impossible to display and the display quality of the display is displayed. However, there is a drawback that it deteriorates. Especially, under severe conditions such as vehicle mounting, this defect easily occurs and becomes a serious problem.

Further, when the smoothness and flatness are low, the gap of the liquid crystal layer is not uniform, and the plastic film substrate itself causes optical unevenness, resulting in uneven display color and uniform voltage distribution. The relationship of transmittance is not shown. In particular, when the thermal durability is low, the flatness is likely to be impaired, which becomes a serious problem under severe conditions such as vehicle mounting.

Further, even when the plastic film substrate itself has birefringence, the display quality of the display is deteriorated due to the deterioration of coloring and contrast of the display.

These are because the liquid crystal display follows the principle of electrically switching the polarization direction in the liquid crystal layer.

In order to solve such problems, Japanese Patent Laid-Open No. 61-41
No. 122, JP-A-63-71829 and JP-A-3-9323 propose various improved plastic film substrates to improve these points. However, although the plastic substrates proposed therein have improved properties, respectively, the present condition is that the properties relating to display quality and their long-term reliability, which have already been shown, are not fully satisfied.

The present invention has been made in view of the above circumstances, and provides a transparent electrode substrate which is a plastic film substrate which can solve the above-mentioned problems comprehensively and can be used for a liquid crystal display panel as well as a glass substrate. With the goal.

[0011]

The above object can be achieved by the present invention described below. That is, the present invention, on one or both sides of the plastic film, a gas barrier layer made of a polymer resin is laminated via an anchor coat layer, further using a laminated substrate having a protective layer laminated on one or both sides of the laminate, In a transparent electrode substrate provided with a transparent conductive layer on one or both surfaces of the outermost surface thereof, the transparent conductive layer is made of an amorphous indium oxide containing tin in an indium / tin weight ratio of 95/5 to 85/15. And the film thickness is 20 to 2
A transparent conductive layer having a thickness of 70 to 200 μm, which is a transparent conductive layer having a retardation value of 20 nm or less and a slow axis variation of ± 15 degrees or less. The surface roughness of the surface of the laminated substrate on which the transparent conductive layer is provided has a center line average roughness Ra of 40 nm or less.

The present invention described above is a laminated substrate having excellent optical isotropy and surface flatness obtained by laminating each layer so as to satisfy the above-mentioned surface roughness on the above-mentioned optically isotropic plastic film, and optical characteristics. By combining the above-mentioned transparent conductive layer, which has excellent properties, an anchor coat layer, a gas barrier layer, and a protective layer are provided to ensure gas permeation resistance and water vapor permeation resistance that do not hinder practical use, and STN, which has the strictest quality standards. Variation of the cell gap, which is said to be necessary for a standard LCD panel, is ± 5
It was made by discovering that the surface property realizing 0 nm or less was obtained and the display quality which was practically satisfactory was obtained.

That is, when the influence of the surface property of the transparent electrode substrate on the display quality including the above-mentioned influence on the cell gap was examined, no problem was found if the surface roughness Ra was 40 nm or less, and the Ra value was 40 nm. It has been found that when the value exceeds the range, when a liquid crystal cell is manufactured, the alignment of the liquid crystal layer is affected, the operation characteristics are uneven, and the contrast is also varied.

By the way, the surface roughness of the transparent conductive layer of the transparent electrode substrate is as long as the thickness of the transparent conductive layer is within the range of the present invention.
Since the surface roughness of the surface on which the transparent conductive layer is provided almost develops as it is, the above-mentioned findings are, in other words, the surface roughness of the above-mentioned laminated substrate, which is an intermediate laminated body of the transparent electrode substrate, as Ra value of 40 n.
It shows that it is necessary to be m or less. As shown in the examples, the present invention sufficiently satisfies this surface property by the above-mentioned constitution and thereby realizes the above display quality.

Here, the center line average roughness Ra is TOPO manufactured by WYCO, which uses a phase shift interferometry as a measurement principle.
3D is a center line average roughness Ra obtained by measuring a square surface having a side length of 256 μm on the film surface at a magnification of 40 × at an interval of 1 μm.

The details of the present invention will be described below.

In the present invention, as described above, the plastic film of the substrate is used as a transparent electrode substrate, which is a liquid crystal display panel which suppresses coloring of display and deterioration of contrast and is excellent in display quality, specifically, a large size such as STN. The retardation value is 20 nm or less, and the variation of the slow axis is ±, in order to set the hue unevenness of the liquid crystal display panel that performs fine display by simple matrix drive in the panel to a range that does not pose a practical problem.
Has optical isotropy within 15 degrees and a thickness of 70-200μ
The thing of m is used.

Although the birefringence of the plastic film is unavoidable at present, the plastic film of the present invention has the dispersion of the slow axis, which represents the optical axis of the birefringence, within ± 15 degrees and is aligned in one direction. Since it is in the range considered to be, there is an effect that optical design in combination with a retardation plate is easy.

The surface property is preferably 10 nm or less, more preferably 5 nm or less Ra so that the surface roughness of the laminated substrate is 40 nm or less.

The retardation value described here is the product Δn · d of the known difference Δn in birefringence and the film thickness d.
It is necessary that the measured value is at a wavelength in the visible light range, and since plastic generally has wavelength dispersion characteristics of refractive index, the measured value is 590 nm as a typical value. Further, the dispersion angle of the slow axis is measured at the same wavelength, but the retardation value and the angle of the slow axis can be measured by a well-known birefringence measuring device. For example, a multi-wavelength birefringence measuring device M- manufactured by JASCO
It can be easily measured at 150 or the like.

When a transparent electrode substrate for a liquid crystal display panel is constructed using such a plastic substrate, the optical characteristics thereof are that the light transmittance at 550 nm is 80.
% Or more and the haze value is preferably 1% or less. That is, when the light transmittance is lower than 80%, when a liquid crystal cell is formed by using the light transmittance, the light utilization efficiency is lowered, the display is darkened, and the contrast is lowered. In addition, when the haze value is higher than 1%, when the liquid crystal cell is formed by using the haze value, the transmitted light is scattered and the polarization degree of the polarized light transmitted through the polarizing plate is lowered. . This reduces the contrast.

Here, the light transmittance is a transmittance with a parallel light ray using a known visible spectrophotometer, and the haze value is a value when measured with a C light source using NDH-300A manufactured by Nippon Denshoku. Is.

The plastic film used in the present invention is
Films of polyarylate or polycarbonate are preferred. Generally in plastic materials, thermal, mechanical,
Materials are limited to obtain practical gas permeation resistance while maintaining optical characteristics, and it is difficult to meet a practical level in terms of weight reduction, but polyarylate or polycarbonate is thermally, Both mechanical and optical properties are good, and other properties can be sufficiently put to practical use by laminating appropriate functional films described later.

By the way, the polyarylate or polycarbonate film has a low gas permeation resistance, and when a transparent conductive layer is directly provided on these films to form a transparent electrode substrate, a liquid crystal display panel using the same is used as described above. It may cause bubbles in the liquid crystal. Therefore, as known from Japanese Patent Publication No. 6-44116 and the like, the gas permeation resistance can be improved by forming a gas barrier layer made of a polymer resin having a high gas barrier property.

However, in general, the adhesiveness between polyarylate or polycarbonate and a polymer resin having a high gas barrier property, which is a different material, is low, and most of the combinations cause the gas barrier layer to be easily peeled off. Can't get

For this purpose, it is preferable to provide an anchor coat layer, which will be described later, made of a material having good adhesiveness with both of them to improve the adhesiveness of both.

By the way, in the laminated body having such a laminated constitution, the gas permeability and the water vapor permeability thereof are 1 cc / m ² · day · atm or less, and the water vapor rate is from the viewpoint of preventing deterioration of the liquid crystal display panel. Transmittance is 20g / m ² · day · at
m or less.

Gas permeability is more than 1 cc / m ² · day · atm, or water vapor permeability is 20 g / m ² · day · a
A liquid crystal cell having a thickness of 7 μm is sandwiched between two transparent electrode substrates using the above-described laminated body, which is more than tm, and sealed with a sealant to form a liquid crystal cell.
When an accelerated durability test of time was performed, bubbles were generated in the liquid crystal layer. Therefore, from the practical viewpoint, the above range is preferable.

The gas permeability in the present invention is MOCON.
The oxygen transmission rate value and water vapor transmission rate measured at 25 ° C. using Oxytran 2/20 MH manufactured by Mfg. Co. are the values measured at 25 ° C. and 90% RH using Permatran W1A manufactured by MOCON.

As the gas barrier layer of such a transparent electrode substrate, known ones such as those described in the above publications can be applied, but an acrylonitrile component, a vinyl alcohol component,
At least one selected from the group consisting of a vinyl alcohol copolymer component or a vinylidene halide component is used.
A polymer resin containing 0 mol% or more is preferably applied.

These polymer resins have a gas permeation coefficient of 0.1 cc · mm / m ² · day · atm or less, and a practical thickness of 100 μm for the gas barrier layer.
The gas permeability of the transparent electrode substrate is 1 cc / m ² · day · a
tm can be achieved.

Further, among these, when there is an acrylonitrile component, the selectivity of the solvent is limited, and
When there is a vinylidene halide component, those containing a vinyl alcohol component and a vinyl alcohol copolymer component are particularly preferred from the viewpoints of workability and environmental problems that halogen is generated during incineration.

Other than this, for example, when polymethyl methacrylate is used as the gas barrier layer, the gas permeability is 1 cc.
The thickness of the gas barrier layer itself must be 6 mm or more in order to obtain / m ² · day · atm or less, and a practical transparent electrode substrate for a liquid crystal display panel cannot be obtained.

The above anchor coat layer includes a polyester resin having a hydrophilic group from the viewpoint of adhesiveness with the gas barrier layer of the polymer resin and the polycarbonate film of the substrate,
At least one selected from the group consisting of acrylic resin, polyurethane resin, and ionic polymer complex is preferably applied. Among them, those that do not have tackiness on the surface after forming the anchor coat layer are preferable, and acrylic resin and polyurethane resin are more preferable from such a viewpoint.

With the above anchor coat layer, it is possible to obtain excellent adhesion between the polyarylate or polycarbonate film and the gas barrier layer with a peel strength of 150 g / cm or more, and prevent deterioration such as interfacial peeling in a durability test or the like. A highly reliable laminated body having practically sufficient characteristics can be obtained.

In the case where there is no anchor coat layer or when other materials such as polyethylene glycol or a diglycidyl ether compound of bisphenol A and hexamethylenediamine are used as the anchor coat layer, or epoxy resin or polymethylmethacrylate is used, polyarylate is used. Alternatively, the adhesion between the polycarbonate film and the gas barrier layer is low, and the peel strength is 5 to 5
It is about 100 g / cm, and is easily peeled off, for example, by peeling off the adhesive such as cellophane tape. In such a laminated body, the laminated body may be peeled off in the manufacturing process of the liquid crystal cell, resulting in a poor appearance and poor reliability.

The peel strength in the present invention, which is the standard of good or bad adhesion, is T of JIS-K-7113 standard.
It is a value obtained when the mold peeling test is performed at 25 ° C.

Further, in the present invention, a protective layer for blocking water, an organic solvent and the like is provided on at least one surface of the laminate. The protective layer includes a thermo-crosslinkable resin curing agent of at least one selected from the group consisting of epoxy resin, phenoxy resin, phenoxy ether resin, phenoxy ester resin, acrylic resin, melamine resin, phenol resin, and urethane resin. The object is preferably applied. Among them, a cured product of an epoxy resin, a phenoxy resin, a phenoxy ether resin, or a phenoxy ester resin is preferable in terms of workability and protection performance.

The above-mentioned protective layer has good adhesiveness with the lower layer, and the laminated substrate having this protective layer laminated thereon has excellent durability to water, organic solvents, etc., high surface hardness, scratch resistance and the like. It becomes a substrate on which a transparent conductive layer of a transparent electrode substrate having excellent mechanical properties is formed.

In the case of a transparent electrode substrate using a laminate without such a protective layer, the electrode substrate for a liquid crystal panel will be whitened or dissolved at the time of washing with an organic solvent in the process of producing a liquid crystal cell or when forming an alignment film. In addition, when there is no water resistance, the water vapor transmission rate of the transparent electrode substrate is large, and as described above, a defect as a liquid crystal cell occurs.

The above anchor coat layer, gas barrier layer,
The protective layer is formed by a known film forming method such as a wet coating method. As is well known, the wet coating method is a method in which a raw material for forming a layer is formed into a solution suitable for coating with a solvent or the like, if necessary, and applied on a substrate with a predetermined film thickness, and necessary treatment such as drying is performed. It is a method of laminating layers, and specifically, there are various methods such as a spin coating method, a Meyer bar coating method, a forward rotation roll coating method, a gravure coating method and a reverse coating method.

In the present invention, the surface roughness of the surface of the laminated substrate obtained by laminating the above anchor coat layer, gas barrier layer and protective layer on a plastic film is Ra of 40 as described above.
The thickness of each of these layers,
It can be obtained by appropriately combining materials, forming methods, etc., but the influence of the surface property of the plastic film is large,
From this point, it is preferable that the surface has Ra of 10 nm or less as described above.

The transparent conductive layer provided on the above laminated substrate is
Known metals such as tin, indium and titanium, or oxides thereof can be applied. Then, these transparent conductive layers can be provided by known thin film forming means such as vapor deposition and sputtering.

In the present invention, among others, it is composed mainly of non-crystalline indium oxide, and tin is contained in an amount of 5 to 5 as its composition.
The content of 15% by weight and the thickness of the transparent conductive layer in the range of 20 to 200 nm are preferable in terms of transparency, conductivity, flexibility and the like.

Crystalline indium oxide is higher in transparency and conductivity than non-crystalline indium oxide and is preferable as an electrode material in these respects, but it is formed on a highly flexible film. When used as a film, the film is liable to crack when bent, and there is a problem in reliability, handleability during assembly, and the like.

In the present invention, the crystallinity and non-crystallinity of indium oxide are defined as follows. When the surface of the formed indium oxide is observed with a transmission electron microscope, fine crystal grains having a diameter of about 100 μm scattered on the amorphous film surface are observed. With this observation method, the unit area (100μ
The case where the crystal grain area per m ² ) is 20% or less is defined as amorphous, and the case where it exceeds 20% is defined as crystalline.

Although indium oxide is originally a transparent electric insulator, it becomes a semiconductor when it contains a trace amount of impurities or when it is slightly oxygen-deficient. As a preferable semiconductor metal oxide, indium oxide containing tin or fluorine as an impurity can be cited, and indium oxide containing 5 to 15% by weight of tin has good conductivity while maintaining high transparency. It is preferable from the viewpoint of exhibiting properties.

The thickness is preferably in the range of 20 to 200 nm. If the thickness is less than 20 nm, the electrical sheet resistance becomes high, and the conductivity is insufficient as an electrode substrate for a liquid crystal panel. Further, when the thickness is more than 200 nm, the influence on the light transmittance of the entire electrode substrate cannot be ignored, and it becomes difficult to obtain the light transmittance of 80% or more at the wavelength of 550 nm required for the transparent electrode substrate of the liquid crystal display panel, and the bending When it is done, it is easily cracked, and the reliability and the above-mentioned handleability are insufficient.

The polycarbonate used in the present invention is not particularly limited as long as it satisfies the above-mentioned optical characteristics. However, due to thermal characteristics, the bisphenol A component is bisphenol A alone, and the molecular weight is 30,000 or more. Polycarbonate having a glass transition temperature of 150 ° C. or higher is preferably applied. From the viewpoint of solubility in cast film formation, a copolymerization component such as a fluorene component or an isophorone component may be added.

By the way, although the average molecular weight of the polycarbonate resin is distinguished by the difference in the degree of polymerization, up to now, those having an average molecular weight of 20,000 to 25,000 have been used for general purposes, and are ejected from an optical disk or the like. For molding, the average molecular weight is 12,000 to 15,000.
A low degree of polymerization is used. Here, the average molecular weight means the number average molecular weight, and can be easily determined by a known measuring means such as GPC.

However, in order to satisfy the heat resistance required in the panelizing process for assembling the liquid crystal panel, the liquid crystal substrate which is the application of the present invention has a heat resistance of glass transition temperature of 150 ° C. or higher. preferable. That is, when the glass transition temperature is 150 ° C., it is possible to sufficiently withstand the high temperature processes of the alignment film forming step, the sealant thermosetting step and the heat sealing step in the liquid crystal panel assembling process.

In the case of a polycarbonate composed of a bisphenol component consisting only of bisphenol A and having an average molecular weight of 30,000 or more, a glass transition temperature of 150 ° C. or more, which is preferable for the present invention, and mechanical properties are sufficient. You can get something. The optimum average molecular weight is selected in consideration of the balance between heat resistance, mechanical properties and economy.

As a method for forming a film, known methods such as a solution casting method and a melt extrusion method can be applied, but the solution casting method is preferably applied to the present invention from the viewpoint of the obtained optical characteristics. It That is, the retardation value used in the present invention is 20 nm or less, and the variation of the slow axis is ±.
It has an optical isotropy of 15 degrees or less and a thickness of 70-200μ.
A film having an m and a surface roughness Ra of 5 nm or less can be continuously produced in a large amount by the solution casting method, but it is not easy by other melt extrusion methods.

In the melt extrusion method, die lines, gels, fish eyes and carbides are easily generated in the film, and it is difficult to obtain a film having good smoothness over a wide area, but the solution casting method is used. Has the advantage that there are few such drawbacks. Furthermore, the solution casting method is a method in which a polymer is dissolved in a solvent and cast from a die onto a flat substrate to form a film, and has an advantage that a solvent-soluble polymer can be formed into a film.

However, when a polycarbonate film is formed by this solution casting method, the solvent used for film formation may remain in the film. The residual solvent plasticizes the film, resulting in a decrease in its glass transition temperature and a decrease in dimensional stability. From this point, the residual amount of the residual solvent is preferably 0.2% by weight or less, more preferably 0.1% by weight or less. This residual amount can be reduced by heat treatment, use of a low boiling point solvent, and the like.

Examples of the present invention will be described below.

[0057]

【Example】

Example 1 A polycarbonate film was formed by the solution casting method using a polycarbonate resin having an average molecular weight of 37,000, in which the bisphenol component was bisphenol A only.

That is, the polycarbonate resin was dissolved in methylene chloride as a solvent to a concentration of 20% by weight, and the obtained solution was cast on a polyester film having a thickness of 175 μm by a die coating method to form a film. Then, in a drying step, the solvent was evaporated and removed until the residual solvent concentration became 13% by weight, and then the polycarbonate film was peeled from the polyester film. The obtained polycarbonate film was dried in a drying oven at a temperature of 120 ° C. while balancing the vertical and horizontal tensions until the residual solvent concentration became 0.08% by weight.

The polycarbonate film obtained had a thickness of 102 μm. Also 590n of this film
The retardation value at m is 8 ± 2n in the width direction.
The variation in m and the slow axis was within ± 8 degrees with respect to the MD direction.

Next, an anchor coat layer having a thickness of 3 μm, a gas barrier layer having a thickness of 15 μm, and a protective layer having a thickness of 6 μm are sequentially formed on both surfaces of this film as follows, respectively, to form a laminated substrate. It was created.

The anchor coat layer is a cross-linked polyurethane resin. Specifically, A310 manufactured by Takeda Pharmaceutical Co., Ltd. is used as the polyol component of the main component, and A3 manufactured by the same company is used as the isoanato component of the curing agent. On the other hand, a solution obtained by mixing 25 parts of A3 was applied onto a polycarbonate film and heat-treated at 100 ° C. for 30 minutes to form a film.

The gas barrier layer is a cross-linked vinyl alcohol copolymer, specifically, an ethylene-vinyl alcohol copolymer Evar-1 EPL-1 manufactured by Kuraray Co., Ltd.
01 (ethylene content of 27 mol%), 20 parts of this, 63 parts of water as a solvent, 43 parts of n-propyl alcohol, and 5 parts of methylolated melamine as a cross-linking agent were heated and mixed, and a solution was coated on the anchor coat layer. Then, it was formed by heat treatment at 130 ° C. for 15 minutes.

The protective layer is a crosslinked phenoxy resin, specifically, phenoxy resin Phenototo YP-50 manufactured by Tohto Kasei Co., Ltd. is used, and 40 parts of this, 40 parts of methyl ethyl ketone as a solvent and 20 parts of 2-ethoxyethyl acetate are used. Is mixed with 40 parts of Takeda Yakuhin Kogyo Co., Ltd. A3 as a cross-linking agent, the solution is coated on the barrier layer, and heat-treated at 80 ° C. for 5 minutes and at 130 ° C. for 3 hours to be formed. did.

The surface roughness of the laminated substrate obtained above is Ra.
The value was 22 nm. The gas permeability is 0.1c
c / m ² · day · atm, water vapor transmission rate is 10 g / m ² ·
It was day and atm.

On the protective layer on the polyester film side of this laminated substrate, an indium-tin oxide layer was formed as a transparent conductive layer by the sputtering method as follows.

As the sputtering target, an indium-tin oxide target having a weight ratio of indium / tin = 90/10 and a packing density of 90% was used. Then, the laminated substrate was set in a continuous sputtering apparatus, the gas was exhausted to a pressure of 1.3 mPa, and then a gas having a volume mixture ratio of Ar / O ₂ = 98.5 / 1.5 was introduced, and the atmospheric pressure was 0.27 Pa.
I made it. Then, the substrate temperature is set to 50 ° C., DC sputtering is performed at an input power density of 1 W / cm ² , and the film thickness is 1
A transparent conductive layer made of 30 nm of indium-tin oxide was formed.

The transparent conductive layer thus obtained was non-crystalline, with the abundance ratio of fine crystal grains being 0% in area ratio. Further, the surface resistance value was 40Ω in a square measurement in which electrodes were arranged on opposite sides of the unit square. Hereinafter, this surface resistance value is shown by Ω / □.

The transparent electrode substrate 5 thus obtained was used.
The light transmittance at 50 nm was 85%, and the haze value was 0.5%.

As a result of examining the peel strength between the polycarbonate film and the gas barrier layer, it was 240 g / cm.

Further, the transparent electrode substrate was cut with a cutter knife, and a cellophane tape was adhered to the cut portion from the protective layer side,
When peeled off from the cut side, no delamination was observed. Adequate adhesion between layers was confirmed.

Width 1 cm and length 10 cm from the transparent electrode substrate
The sample was cut out and a bending resistance test was performed. The test was conducted by visually observing a case in which a transparent conductive layer was placed on the outside and an inside was wound on a metal rod of 1 cmφ by 180 ° for 1 minute and then held. As a result, no change in appearance of the transparent conductive layer was observed, and sufficient flex resistance was confirmed.

Next, the coloring property between the polarizing plates of this transparent electrode substrate was examined. First, a 5 cm square sample was cut out from this transparent electrode substrate. Then, this sample was sandwiched between a pair of polarizing plates, and one polarizing plate and further the sample were rotated to visually observe a change in color. As a result, no color change was visually observed.

Next, a solvent resistance test was conducted as follows. 5% KOH water, acetone, and n-methylpyrrolidone were dropped on the surface of the protective layer, and the change after standing for 5 minutes was visually observed. No change was seen in the result.

Further, when heat treatment was carried out at 130 ° C. for 4 hours, there was no change in film warp and no change in appearance.
Also, when the change in surface resistance before and after this test was examined,
The resistance value after the test / the resistance value before the test = 1.2, and it was confirmed that the change in the resistance value was in a range where there was no practical problem.

An STN liquid crystal cell was prepared using this transparent electrode substrate and the display performance was examined, but the contrast was sufficient, and no color unevenness was observed during operation.

Further, a reliability test was conducted on this STN liquid crystal cell. The reliability test is a heat resistance test at a temperature of 80 ° C for 1,000 hours, and a temperature of 60 ° C and a relative humidity of 90% RH.
Two kinds of moisture resistance test for 1,000 hours were conducted. As a result, no change in appearance and display performance was observed. It was confirmed that the liquid crystal cell had sufficient durability.

Example 2 A polyarylate film was formed by the solution casting method using Polyarylate U-100 manufactured by Unitika Ltd. as follows.

That is, the polyarylate resin was dissolved in methylene chloride as a solvent so as to have a concentration of 25% by weight, and the resulting solution was applied to a thickness of 1 by a die coating method.
It was cast on a polyester film of 75 μm to form a film. Then, in the drying process, the solvent is removed to a residual solvent concentration of
After removing by evaporation to a weight percentage, the polyarylate film was peeled off from the polyester film. The polyarylate film thus obtained was dried in a drying oven at a temperature of 120 ° C. while the tension in the vertical and horizontal directions was balanced, and the residual solvent concentration was 0.0
It was dried to 8% by weight.

The obtained polyarylate film had a thickness of 101 μm. Also this film's 590nm
Retardation value in the width direction is 11 ± 3n
The dispersion of m and the slow axis was within ± 9 degrees centering on the MD direction.

Then, in exactly the same manner as in Example 1, an anchor coat layer having a thickness of 3 μm, a gas barrier layer having a thickness of 15 μm, and a protective layer having a thickness of 6 μm were sequentially formed on both sides of this film. A laminated substrate was prepared and a transparent conductive layer was formed on one of the protective layers to obtain a transparent electrode substrate.

The surface roughness of the obtained laminated substrate is 3 in terms of Ra value.
It was 1 nm. The gas (oxygen) permeability is 0.1.
cc / m ² · day · atm, water vapor transmission rate 8 g / m ² ·
It was day and atm. The characteristics of the transparent conductive layer were exactly the same as in Example 1, were non-crystalline, and had a surface resistance of 40Ω. The light transmittance of the transparent electrode substrate at 550 nm was 85%, and the haze value was 0.6%. As a result of examining the peel strength between the polyarylate film and the gas barrier layer, 250 g / c
It was m.

Further, the transparent electrode substrate was cut with a cutter knife, and a cellophane tape was adhered to the cut portion from the protective layer side,
When peeled off from the cut side, no delamination was observed. Similar to Example 1, the interlayer adhesion was sufficient.

Also in the flex resistance test and the coloring test, the same good results as in Example 1 were obtained. In addition, the same good results as in Example 1 were obtained in the solvent resistance test and the heat resistance test.

Further, observation of display performance in STN liquid crystal cell,
Also in the reliability test, as in Example 1, good results were obtained.

Example 3 The same polycarbonate film as in Example 1 was coated on both sides with a 2 μm anchor coat layer,
A 4 μm gas barrier layer and an 8 μm protective layer were sequentially formed as follows.

The anchor coat layer is made of acrylic resin. Specifically, PC7A manufactured by Shin-Etsu Chemical Co., Ltd., which is an acrylic resin-based coating material, is coated on a polycarbonate film,
It was formed by heat treatment at 100 ° C. for 5 minutes.

The polyvinyl alcohol resin was used for the gas barrier layer. Specifically, polyvinyl alcohol resin PVA-117 manufactured by Kuraray Co., Ltd. was used, and a solution prepared by heating and mixing 10 parts of this with 90 parts of water was used. It was formed in the same manner as 1.

The same protective layer as in Example 1 was used. The surface roughness Ra value of this laminated substrate was 35 nm. The oxygen transmission rate was 0.3 cc / m ² · day · atm, and the water vapor transmission rate was 18 g / m ² · day · atm. On one protective layer of this laminated substrate, indium-
The tin oxide layer was formed under the following sputtering conditions.

As the sputtering target, an indium-tin oxide target having a composition by weight ratio of indium / tin = 93/7 and a packing density of 90% was used. Then, the above-mentioned laminated substrate is set in a continuous sputtering device, and 1.3 mPa
Ar / O ₂ = 98.5 / 1.5 after exhausting to a pressure of
Introduce a gas with a volume mixing ratio of
set to a. Then, the film temperature was set to 85 ° C., DC sputtering was performed at an input power density of 1 W / cm ² , and a transparent conductive layer made of indium-tin oxide having a film thickness of 80 nm was formed.

As a result, the transparent conductive layer obtained was non-crystalline, with the crystal grains being present in an area ratio of 5%. The surface resistance value was 62Ω / □. The transparent electrode substrate thus obtained was evaluated in the same manner as in Example 1. The light transmittance at 550 nm was 81% and the haze value was 0.6%. As a result of examining the peel strength between the polycarbonate film and the gas barrier layer, it was 180 g / cm.

When this transparent electrode substrate was cut with a cutter knife, cellophane tape was adhered to the cut portion from the protective layer side, and peeled from the cut portion side, slight peeling was observed at the end. In the flex resistance test, no change in appearance of the transparent conductive layer was observed. Even in the colorability test, no color change visually occurred. No change was observed in the solvent resistance test.

Further, in the heat treatment test, no change in film warp and no change in appearance occurred. The change in surface resistance before and after the heat treatment test was also small and favorable, ie, resistance value after test / resistance value before test = 1.1.

Regarding the display performance of the STN liquid crystal cell,
The contrast was good and no color unevenness was observed during operation.

Further, in the reliability test, no change was observed in appearance and display performance.

Example 4 In Example 1, the protective layer was made of an epoxy resin different from that of Example 1, and the other conditions were the same as those of Example 1.

The protective layer is specifically 100 parts of Epicoat 828 manufactured by Yuka Shell Epoxy Co., Ltd. and Epicure 1
A mixture of 32 parts of 13 was formed in the same manner as in Example 1.

The surface roughness Ra value of the obtained laminated substrate is 26.
was nm. The oxygen transmission rate was 0.1 cc / m ² · day · atm, and the water vapor transmission rate was 10 g / m ² · day · atm. The following evaluation similar to Example 1 was performed about the obtained transparent electrode substrate. The light transmittance at 550 nm was 85%, and the haze value was 0.7%. A solvent resistance test was conducted, but no change was observed.

A heat treatment test was conducted, but no change in film warp and no change in appearance occurred. Further, the change in surface resistance at that time was after the test resistance value / pre-test resistance value = 1.2, and did not change significantly.

Regarding the display performance of the STN liquid crystal cell,
The contrast was good, and no color unevenness was observed during operation. Furthermore, in the reliability test, no change was observed in the appearance and display performance.

Comparative Example 1 A biaxially stretched PET film having a thickness of 98 μm, a retardation value of 293 ± 20 nm in the width direction and a retardation axis variation of ± 50 degrees centered in the MD direction was applied to one surface of the PET film. The same transparent conductive layer as in Example 1 was formed. Then, the colorability between the same polarizing plates as in Example 1 was examined. As a result, the sample was observed to be colored, and its color changed with the rotation of the polarizing plate and the sample. for that reason,
It was unsuitable for films for transparent electrode substrates, especially for STN. [Comparative Example 2] A polycarbonate film having a thickness of 125 µm was formed by a melt extrusion method from a polycarbonate resin having an average molecular weight of 24000 in which the bisphenol component was only bisphenol A. The retardation value of this film was 32 nm as an average value in the width direction, and the variation of the slow axis angle was ± 20 °.

The same transparent conductive layer as in Example 1 was formed on one surface of this film. Then, the colorability between the same polarizing plates as in Example 1 was examined. As a result, the sample was observed to be colored, and its color changed with the rotation of the polarizing plate and the sample. Therefore, it was unsuitable for films for transparent electrode substrates, especially for STN.

Comparative Example 3 The same transparent conductive layer as in Example 1 was formed directly on one surface of the same polycarbonate film as in Example 1. This polycarbonate film had a gas permeability of 980 cc / m ² · day · atm and a water vapor permeability of 54 g / m ² · day · atm.

Then, in the same manner as in Example 1, a solvent resistance test was conducted on the film surface opposite to the transparent conductive layer.
It was observed that there was no change in 5% KOH water, but that it was instantly whitened with acetone and dissolved with n-methylpyrrolidone. Therefore, it is difficult to pattern the transparent conductive layer and form the alignment film.

Comparative Example 4 Only the same protective layer as in Example 1 was laminated to both sides of the same polycarbonate film as in Example 1 with the same thickness. The gas permeability of this laminated substrate is 280.
cc / m ² · day · atm, water vapor transmission rate is 18 g / m ²
・ It was day ・ atm. The same transparent conductive layer as in Example 1 was formed on one surface of this laminated substrate.

When the same solvent resistance test as in Comparative Example 3 was carried out, no change was observed with any solvent. When an STN liquid crystal cell was produced using this transparent electrode substrate and a reliability test was conducted in the same manner as in Example 1, air bubbles were generated in the liquid crystal layer and the display characteristics were degraded.

Comparative Example 5 The gas barrier layer used in Example 1 was directly molded on both sides of the same polycarbonate film as in Example 1 without providing an anchor coat layer, with the same thickness.

The peel strength of the film / gas barrier layer was measured and found to be 4 g / cm. Also, in the same cellophane tape adhesion peeling test as in Example 1, the entire surface of the gas barrier layer was easily peeled off. Therefore, it was difficult to manufacture a liquid crystal cell.

Comparative Example 6 The same polycarbonate film as in Example 1 was coated on both sides with an anchor coat layer of 1 μm and 1 μm.
A 5 μm gas barrier layer and a 6 μm protective layer were sequentially provided.

Here, the anchor coat layer was formed in the same manner as in Example 1 using AP-133 manufactured by Nippon Unicar Co., Ltd., which contains aminoalkylalkoxysilane as a component. The gas barrier layer and the protective layer were the same as in Example 1.

The peel strength of the film / gas barrier layer was measured and found to be 15 g / cm. Also, in the same cellophane tape adhesion peeling test as in Example 1, the entire surface of the gas barrier layer was easily peeled off. Therefore, it was difficult to manufacture a liquid crystal cell.

Comparative Example 7 An indium-tin oxide layer which is a transparent conductive layer was formed on one surface of the same laminated substrate as in Example 1 by the sputtering method as follows.

As a sputtering target, an indium-tin oxide target having a composition of indium / tin = 95/5 by weight and a packing density of 90% was used. After setting the laminated substrate in the continuous sputtering apparatus and evacuating it to a pressure of 1.3 mPa, a gas having a volume mixture ratio of Ar / O ₂ = 99/1 was introduced to make the atmospheric pressure 0.27 Pa. Then, the film temperature is set to 50 ° C., and the input power density is 1 W / cm ²
DC sputtering was performed at. After that, 140 ℃ 90
Heat treatment for minutes was performed.

As a result, the transparent conductive layer thus obtained was crystalline, with an area ratio of crystal grains of 35%. The film thickness was 130 nm, and the surface resistance value was 40 Ω / □.

Then, the bending resistance test of this transparent electrode substrate was conducted in the same manner as in Example 1. As a result, the transparent conductive layer had visible cracks. Therefore, it was difficult to manufacture a liquid crystal cell.

[Comparative Example 8] An indium-tin oxide layer as a transparent conductive layer was formed on one surface of the same laminated substrate as in Example 1 by the sputtering method as follows.

As a sputtering target, an indium-tin oxide target having a composition of indium / tin = 99/1 by weight and a packing density of 90% was used. After setting the laminated substrate in the continuous sputtering apparatus and evacuating it to a pressure of 1.3 mPa, a gas having a volume mixing ratio of Ar / O ₂ = 98.5 / 1.5 was introduced to make the atmospheric pressure 0.27 Pa. . And set the film temperature to 50 ℃, input power density 1W
DC sputtering was performed at / cm ² .

As a result, the transparent conductive layer obtained was non-crystalline, in which the proportion of crystal grains present was 0% in area ratio. The film thickness was 130 nm, and the surface resistance value was 45 Ω / □.

550 n of the transparent electrode substrate thus obtained
The light transmittance at m was 85% and the haze value was 0.6%.

When this sample was heat-treated at 130 ° C. for 4 hours, no change in film warp and no change in appearance occurred. However, as a result of examining the rate of change in resistance, the resistance value after the test / initial resistance value = 2.9, and the resistance value changed significantly, and the thermal stability was poor.

[Comparative Example 9] An indium-tin oxide layer as a transparent conductive layer was formed on one surface of the same laminated substrate as in Example 1 by the sputtering method as follows.

As the sputtering target, an indium-tin oxide target having a composition of indium / tin = 80/20 by weight and a packing density of 90% was used. After setting the laminated substrate in the continuous sputtering apparatus and evacuating it to a pressure of 1.3 mPa, a gas having a volume mixing ratio of Ar / O ₂ = 98.5 / 1.5 was introduced to make the atmospheric pressure 0.27 Pa. .
Then, set the film temperature to 60 ° C and input power density 1
DC sputtering was performed at W / square cm.

As a result, the transparent conductive layer obtained was non-crystalline, in which the proportion of crystal grains was 0% in area ratio. The film thickness was 130 nm, and the surface resistance value was 60 Ω / □.

550 n of the transparent electrode substrate thus obtained
The light transmittance at m was 78%, and the haze value was 1.2%.

An STN liquid crystal cell was produced using this transparent electrode substrate and the display performance was observed, but the display was dark and the contrast was low.

Comparative Example 10 A transparent conductive layer was formed on one surface of the same laminated substrate as in Example 1 in the same manner as in Example 1. However, when forming, by sputtering for a long time,
The film thickness was increased to 220 nm.

A bending resistance test of this transparent electrode substrate was conducted in the same manner as in Example 1. As a result, the transparent conductive layer had visible cracks. Therefore, it was difficult to manufacture a liquid crystal cell.

Comparative Example 11 The same laminated substrate as in Example 1 was embossed on one surface to adjust the surface roughness.
The surface roughness of the processed surface was Ra value of 43 nm.
The same transparent conductive layer as in Example 1 was formed on this surface.

An STN liquid crystal cell was prepared using this transparent electrode substrate and the display performance was observed, but the liquid crystal was not uniformly aligned. Therefore, color unevenness was confirmed and uniform display characteristics were not exhibited.

[0129]

INDUSTRIAL APPLICABILITY As described above, the present invention is a functional layer used for a transparent electrode of a display panel such as a liquid crystal display device, a touch panel or a lighting panel, which improves gas permeation resistance, water vapor permeation resistance and long-term reliability. By improving the uniformity, smoothness, and flatness of the optical characteristics of a transparent electrode substrate that uses a plastic film with a multilayered structure in which is laminated, it is possible to obtain a display performance that is comparable to that of a transparent electrode substrate of a glass substrate. It is a transparent electrode substrate, and it is possible to make a flexible structure as a whole, and it also contributes greatly to improving the safety of display panels, touch panels, lighting panels, etc. and expanding applications. is there.

Further, the transparent electrode substrate of the present invention can be continuously manufactured by a long substrate, which is very effective in cost reduction.

Thus, the present invention makes a great industrial contribution.

Claims (8)

[Claims] 1. A gas barrier layer is laminated on one or both sides of a plastic film via an anchor coat layer,
Further, in a transparent electrode substrate using a laminated substrate in which a protective layer is laminated on one surface or both surfaces of the laminate, and a transparent conductive layer is provided on one or both surfaces of the outermost surface, the transparent conductive layer is made of tin and indium / tin. A transparent conductive layer made of an amorphous indium oxide containing 95/5 to 85/15 in a ratio and having a film thickness in the range of 20 to 200 nm. The plastic film has a retardation value of 20 nm or less and a slow phase. Has optical isotropy with axis variation within ± 15 degrees,
A transparent electrode substrate, which is a plastic film having a thickness of 70 to 200 μm, and the surface roughness of the surface of the laminated substrate on which the transparent conductive layer is provided is 40 nm or less in terms of centerline average roughness Ra. 2. The transparent electrode substrate according to claim 1, which has a light transmittance of 80% or more at a wavelength of 550 nm and a haze value of 1% or less. 3. The method according to claim 1, wherein the gas barrier layer is a hardened layer containing a vinyl alcohol component or a vinyl alcohol copolymer component, and the anchor coat layer is an acrylic resin or a polyurethane resin. The transparent electrode substrate described. 4. The transparent electrode substrate according to claim 1, wherein the protective layer is a cured product of an epoxy resin, a phenoxy resin, a phenoxy ether resin, or a phenoxy ester resin. 5. The transparent electrode substrate according to claim 1, wherein the plastic film is made of polycarbonate or polyarylate. 6. The transparent electrode substrate according to claim 5, wherein the polycarbonate film has a bisphenol component of bisphenol A only, has a molecular weight of 30,000 or more and a glass transition point of 150 ° C. or more. 7. The transparent electrode substrate according to claim 6, wherein the polycarbonate film is a film formed by a solution casting method. 8. The transparent electrode substrate according to claim 7, wherein the polycarbonate film has a residual solvent concentration of 0.2% by weight or less.