JPH0854615A - Film substrate for liquid crystal display panel - Google Patents

Abstract

PURPOSE:To improve anti-double refraction property, mechanical characteristics, dimensional stability and heat resistance. CONSTITUTION:Polymer film of an aromatic polycarbonate is used as the substrate. This polycarbonate consists of 4 copolymer of bisphenol A in which a bisphenol component comprising a perhydroisophorone skeleton or fluorene skeleton is copolymerized by 5-30mol% copolymn. ratio. Or,polymer film of an aromatic polyester carbonate is used as the substrate. This polyester carbonate consists of a copolymer of bisphenol A in which terephthalic acid or isophthalic acid or a mixture of these are copolymerized by 5 to 30mol% copolymn. ratio. Or, polymer film of an aromatic polyester carbonate is used as the substrate. This polyester carbonate consists of a copolymer of bisphenol A in which a bisphenol component comprising a perhydroisophorone skeleton or fluorene skeleton and terephthalic acid or isophthalic acid or mixture of these are copolymerized by 5-30mol% copolymn. ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film substrate for a liquid crystal display panel which realizes a film liquid crystal display panel having excellent optical characteristics and excellent display quality. It can be used as an electrode material for displays such as body photoelectrodes, surface heating elements, and organic EL electrodes.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements have been highly demanded to be thinner, lighter, larger, arbitrarily shaped, and capable of displaying curved surfaces. In particular, with the expansion of the use of wearable and portable devices such as pagers, mobile phones, electronic organizers, and pen input devices, liquid crystal display panels using plastic as a substrate instead of the conventional glass substrate have been studied, and some have practical applications. It has started to be transformed.

Such a plastic substrate satisfies the demand for weight reduction and thinness as compared with a glass substrate, and has the effect of improving the visibility of the liquid crystal display panel.

[0004]

The conventional plastic substrate is inferior to the glass substrate in terms of optical characteristics. That is, glass has the property of being optically isotropic in nature. On the other hand, in the case of plastics, when molded into a film shape, it has birefringence due to molecular orientation in view of the correlation between the film forming conditions of the plastic film, the optical elasticity coefficient peculiar to the resin, and the characteristics such as birefringence.

If the plastic film used as the substrate has birefringence, the display quality of the display is remarkably deteriorated, such as the coloring and contrast of the display being deteriorated. This is because in order for the liquid crystal display to exhibit the display function, it is based on the principle of visualization of display by optical switching of polarized light.

[0006] In order to improve these problems, improvements for reducing the birefringence (retardation) of the resin, a method of cast polymerization with a single sheet, and the like have been proposed. However, the method proposed hitherto has remarkably low productivity because a very special resin material is used, special production conditions are set, and molding is performed in a single sheet over time. For this reason, there has been no cost competitiveness with respect to the glass substrates used conventionally.

The present invention is to solve the above-mentioned problems in the prior art.
In other words, by reducing the birefringence of the polymer film used for liquid crystal display panel substrates, improving mechanical properties, improving dimensional stability and heat resistance, liquid crystal displays with display qualities that are the same as when using glass substrates. The film substrate for the panel
The purpose is to obtain by a method means that is sufficiently cost-competitive as compared with a glass substrate.

[0008]

In the film substrate for liquid crystal display panel of the present invention, a bisphenol component having a perhydroisophorone skeleton or a fluorene skeleton is copolymerized with bisphenol A at a copolymerization ratio of 5 to 30 mol%. A polymer film of aromatic polycarbonate having an average molecular weight of 30,000 or more and a glass transition temperature of 160 ° C. or more, which is made of a bisphenol A copolymer, is used as a substrate. The copolymerization ratio here is 8 to 20 mo from the viewpoint of the efficiency and economy of the copolymerization.
It is more preferably 1%.

Alternatively, the film substrate for a liquid crystal display panel of the present invention comprises a copolymerization ratio of terephthalic acid, isophthalic acid or a mixture thereof with bisphenol A of 5 to 5.
A polymer film of an aromatic polyester carbonate having an average molecular weight of 30,000 or more and a glass transition temperature of 160 ° C. or more, which is a copolymer of bisphenol A and is copolymerized at 45 mol%, is used as a substrate. The copolymerization ratio here is more preferably 10 to 30 mol% from the viewpoint of copolymerization efficiency and economy.

Alternatively, the film substrate for a liquid crystal display panel of the present invention comprises a bisphenol component having a perhydroisophorone skeleton or a fluorene skeleton, and terephthalic acid or isophthalic acid or a mixture thereof with a bisphenol A copolymerization ratio of 5 to 30 mol%. A polymer film of an aromatic polyester carbonate having an average molecular weight of 30,000 or more and a glass transition temperature of 160 ° C. or more, which is copolymerized with a bisphenol A copolymer,
It is characterized by being used as a substrate.

That is, as a film substrate as a base material of an electrode for a liquid crystal display panel, an aromatic polycarbonate film of a polymer of bisphenol A known as a transparent engineering plastic, or an aromatic polyester carbonate film is heat resistant and economical. It is preferably used from the viewpoints of properties and optical characteristics.

By the way, the average molecular weight of such resins is distinguished by the difference in the degree of polymerization, the molecular weight of the monomers and the copolymerization ratio, but up to now, resins having an average molecular weight of 20,000 to 25,000 have been generally used, or an optical disk. For applications such as injection molding, the average molecular weight is 12
Resins having a low degree of polymerization of 000 to 15,000 are used.

However, the liquid crystal substrate which is the application of the present invention is required to have a heat resistance of 150 ° C. or higher in order to satisfy the heat resistance required in the panel forming process for assembling the liquid crystal panel. Further, in order to obtain sufficient reliability of the liquid crystal display panel, it is preferable that the heat resistance of the film as the substrate is higher, but in order to obtain practical reliability, it is 16
It is required to be 0 ° C or higher. The heat resistance of the resin and its film corresponds to its glass transition temperature.

That is, the film as the substrate must have a glass transition temperature of at least 160 ° C. or higher. When the glass transition temperature is 160 ° C., it is possible to sufficiently endure the high temperature processes of the alignment agent coating step, the sealant heat curing step and the heat sealing step in the liquid crystal panel assembling process.

The glass transition temperature is 3,000 in the case of a polymer containing bisphenol A.
Corresponds to being 0 or more. The higher the average molecular weight, the higher the glass transition temperature. In addition, mechanical characteristics are improved. Further, when a solution is formed into a film, a whitening phenomenon such as crystallization is less likely to occur, which is suitable as a film substrate for this application. If the average molecular weight is 30,000 or more, it is possible to satisfy the heat resistance and mechanical properties required for this application, but the selection of the optimum average molecular weight is carried out in a balance between heat resistance, mechanical properties and economic efficiency.

Such glass transition temperature (160 ° C. or higher)
And to obtain the characteristics of average molecular weight (30000 or more), bisphenol A copolymerized at the above-mentioned copolymerization ratio.
It is necessary to use, as a substrate, a polymer film of aromatic polycarbonate or aromatic polyester carbonate, which is composed of the above copolymer.

The basic skeletons of the bisphenol component of the perhydroisophorone skeleton and the fluorene skeleton are as shown below.

[0018]

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[0019]

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In the present invention, structures other than those exemplified here can be used as the bisphenol component for copolymerization. For example, 1,1-cyclohexylene skeleton, phenylmethylene skeleton, diphenylmethylene skeleton,
A 1,1- (1-phenyl) ethylene skeleton and the like are also preferably used.

Further, as the film substrate for liquid crystal display panel, it is preferable that the display quality of the liquid crystal display panel is excellent. That is, when performing a fine display by dot matrix driving on a large panel such as STN, the retardation value is 15 n in order to reduce the unevenness of the hue of the panel.
It is preferably m or less, and the maximum refractive index direction indicating the direction of the molecular orientation axis, that is, the variation of the slow axis is ± 10 degrees or less. Furthermore, in order to realize multicolor display with good color reproduction on a large STN panel, it is particularly preferable that the retardation value is 10 nm or less and the slow axis angle variation is ± 7.5 degrees or less.

The retardation value described here is
It is necessary to have a measured value at a wavelength in the visible light range, and since the polymer containing bisphenol A has wavelength dispersion characteristics of refractive index, the measured value is 590 nm as a typical value. Further, the variation 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.

Generally, in the case of a film, the haze value, that is, the haze value is high in many cases. This may be affected by the properties of the polymer itself, as well as by additives such as fillers, plasticizers, stabilizers and UV absorbers. It is preferable to set the optimum addition amount of these additives so that the haze value of the film is not increased, and it is preferable to use well-purified polymers as raw materials. Further, since fine irregularities on the surface also have the effect of increasing haze, it is preferable that the film has good flatness and no fine surface roughness. And it is preferable to make the haze value of a polymer film into 0.6% or less by these measures.

As a method for forming a polymer film from a bisphenol A polymer, there are two generally known methods: a melt extrusion film forming method and a solution casting film forming method. Although the solution casting film forming method is inferior in productivity to the melt extrusion method, it is far superior to the melt extrusion method in that there are few defects occurring in the formed film. The defects referred to here mainly mean surface abnormalities such as foreign matter which are external defects. For example, it can be said that a die line, a gelled product, a fish eye, and a carbide are defects inherent to a melt-extruded film. It is preferable to use a polymer film formed by the solution casting method.

The polymer film formed by the solution casting method can be preferably used for this purpose in addition to the advantage that the above-mentioned drawbacks are few. That is, 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 almost any polymer can be formed into a film if it is soluble in the solvent. Therefore, in the case of a polymer of bisphenol A, the average molecular weight is 8,000.
A film of about 0 resin can be formed.

Further, in the solution casting method, heat and tension have a smaller effect on the film than in the melt extrusion method, and the birefringence, which is a drawback in developing this application, can be easily controlled. That is, in the solution casting method, factors that control the birefringence include the characteristics of the die, the condition of the belt, the drying conditions, the film tension and the transport conditions, and the like. Since it can be used and the temperature condition is relatively mild, a polymer film having excellent productivity and excellent birefringence can be formed.

Further, even when additives such as an ultraviolet absorber are added to the film as needed, it is possible to improve the characteristics of the film by appropriately mixing them by selecting a material soluble in the film-forming solvent. Of course, it is also possible to appropriately mix two or more kinds of additives, and a dye or the like may be added as necessary to impart desired coloring easily.

When a bisphenol A polymer is formed by solution film formation, the solvent used for film formation may remain in the film. Residual solvent plasticizes the film,
It causes a decrease in glass transition temperature and a decrease in mechanical properties. Therefore, it is preferable to completely remove the residual solvent, but if the residual amount is 0.3% by weight or less, particularly preferably 0.1% by weight or less, the properties of the polymer film are hardly adversely affected. preferable. The residual amount of the plasticizer or the like added for the effect of plasticizing the film, or the additive such as the surfactant added during the film formation is not included in the residual amount of the solvent in this case.

By the way, the method for reducing the amount of residual solvent is as follows.
Although the heat treatment is mainly used, a low boiling point solvent such as methylene chloride is preferably used as a main solvent for solution film formation in consideration of effects and economy. It is also possible to use a solvent such as dioxolane as the film-forming solvent regardless of the low boiling point solvent. In addition, it is desirable to remove the residual solvent as much as possible during the film formation stage, but after that, use a continuous film heater such as a coater to leave it in an offline process separated from the film formation. It is possible to reduce the amount. The lower the residual solvent concentration, the better the dimensional stability of the polymer film, which is preferable.

Regarding the dimensional stability required in the liquid crystal panel assembling process, it is preferable that the dimensional stability is uniform in the flow direction and width direction of the film at a temperature of 100 ° C. or higher. Therefore, in the case of a film having an amorphous structure such as a polymer of bisphenol A, suitable conditions are set in the film forming conditions, and after heat treatment at 120 ° C for 1 hour, dimensional stability is obtained in both the flow direction and width direction of the film. Sex is 0.0
The dimensional stability is less than 5% and the dimensional stability of the film after heat treatment at 150 ° C. for 30 minutes in both the flow direction and the width direction is 0.1.
It is preferably 1% or less.

The thickness of the polymer film used in the present invention depends on the display quality of the panel when it is processed into a liquid crystal display panel, the ease of handling in the process of forming a substrate, and the panel assembly time. 50 to 200 μm, more preferably 70 to 200 μm, satisfying each of the handling easiness and further considering the efficiency of film formation during solution film formation.
A film having a thickness of ˜200 μm is preferably used.
In addition, since the film thickness unevenness affects the cell gap unevenness of the liquid crystal cell when used as an electrode for a liquid crystal display panel, it is usually preferably ± 5% or less, and particularly preferably ± 2.5%. % Or less is desired.

The retardation value of a polymer film is the product of Δn, which is the difference in refractive index between the slow axis and the fast axis in the plane of the film, and d, which is the thickness of the film. -It is represented by d (unit is nm). The use of a film having less unevenness in thickness leads to a reduction in the variation in retardation value, which is also preferable as an optical characteristic value.

Also, the properties of the polymer films described so far must be achieved not only on one part of the film, but on the whole surface of the film as a substrate. In that case, uniformization of the characteristics in the film flow direction and the film width direction is an important item in this application. And when it becomes an electrode substrate for liquid crystal display panel, it is 2 cm x 5
In some cases, a substrate having a size of about cm is cut from the entire surface of the film to form a panel, and it is important to make the entire characteristics uniform, not only when it is used as a large panel substrate. In most cases, the uniformization of these characteristics is a factor that is determined during the film formation, and it is preferable to perform sufficient control during the film formation.

In order to secure the long-term reliability of the liquid crystal display device, the polymer film used as the substrate is a solvent resistant process having a cross-linking structure by a barrier process or a hard coat process for preventing oxygen and moisture from entering the film. , And transparent electrodes are preferably processed.

For example, when the barrier layer is formed by a wet coating method, the barrier material is polyvinyl alcohol, polyvinyl alcohol-based polymer such as polyvinyl alcohol-ethylene copolymer, polyacrylonitrile, polyacrylonitrile- A known coating material such as a polyacrylonitrile-based polymer of styrene copolymer or polyvinylidene chloride can be used. Then, it can be formed on the film by a known wet coating method such as a reverse roll coating method, a gravure coating method or a die coating method. Further, when the adhesion or wettability with the surface of the substrate or the base material is poor, an easy adhesion treatment such as a primer treatment can be appropriately performed.

When the barrier layer is formed by a dry process such as sputtering or vacuum deposition, Si, Al, Ti, Mg and Zr which are known barrier materials are used.
A thin film of oxide, nitride or oxynitride of at least one metal or a mixture of two or more metals selected from
It can be formed by a known method.

The film thickness of such a barrier layer may be set to a film thickness capable of exhibiting the desired barrier performance. It is also possible to appropriately combine and laminate two or more layers such as dry / wet, dry / dry, and wet / wet.

For the hard coat layer which imparts solvent resistance, known materials such as a resin composition having a crosslinked structure of silicon resin, a crosslinked structure of acrylic resin and a crosslinked structure of epoxy resin are known. It can be formed by using the coating and curing method of. Here, the solvent resistance is intended to impart durability to solvents and chemicals in the process of assembling the liquid crystal panel, alkali resistance,
It is preferable to select materials and curing conditions that can sufficiently secure acid resistance and stability against organic chemicals such as N-methylpyrrolidone.

When the barrier layer and the hard coat layer, the substrate and the laminated structure are mutually constructed, a primer layer may be appropriately provided for the purpose of improving the adhesiveness between the layers. As the primer layer, a silicon material containing a silane coupling agent, an acrylic material,
An acrylic-urethane material or a material containing alkoxytitanium or the like can be appropriately provided by applying and drying by a method such as gravure or microgravure coating.

By the way, in order to be used as an electrode substrate for a liquid crystal display panel, it is necessary to form a transparent conductive film on at least one surface of the polymer film processed as described above. As the transparent conductive film, indium-tin oxide, which is also used in the glass substrate in terms of transparency, conductivity and reliability, is preferably used.
Zinc oxide-based materials can also be used. The transparent conductive film of indium-tin oxide can be formed as a thin film having desired light transmittance and conductivity by a known method such as sputtering, vacuum deposition, or ion plating. In order to improve the adhesiveness between the indium-tin oxide layer and the underlying material, it is possible to appropriately select and primer the primer material described above.

Here, a method of measuring parameters relating to the present invention will be described. First, the average molecular weight means the number average molecular weight, and can be easily determined by a known measuring means such as GPC. Here, the distribution maximum value of the number average molecular weight is merely determined as the average molecular weight, and no restriction is placed on the distribution state of the molecular weight. The glass transition temperature shall be determined by the DSC method. After the film sample was precisely weighed, the residual solvent content was measured by heating at 120 ° C. for 2 hours when the solvent was mainly methylene chloride, and further after heating at 5 ° C. lower than the glass transition temperature for 2 hours. The weight of the sample is weighed, and the difference is expressed as the amount of contained solvent in% by weight.

The dimensional stability of the film is 1 cm in width,
A film sample having a length of 10 cm was cut in the machine direction (MD) and the width direction (TD) of the film, and the length was precisely measured with an electronic micrometer.
It is treated at a predetermined temperature and time, the length is precisely measured again, and the value obtained by dividing the difference between the lengths by the original length is expressed as% to obtain the dimensional stability. And for the thickness unevenness in the width direction of the film, there is a method of being measured by an optical non-contact measuring means and mechanical contact, but even if it is measured by any method, the thickness of the film is an average value. It is necessary that the variation is within a predetermined range.

[0043]

[Examples] Bisphenol A and a bisphenol component having a fluorene skeleton were copolymerized using the phosgene method. Then, an aromatic polycarbonate resin having an average molecular weight of 37,000 was obtained. The copolymerization ratio of the obtained polycarbonate resin is
Bisphenol A / fluorene skeleton = 90/10 (mo
and the glass transition temperature was 170 ° C.

25% by weight of this polycarbonate resin was dissolved in methylene chloride. Then, this solution was cast on a polyester film having a thickness of 175 μm by a die coating method. This was then passed through a drying oven, and when the residual solvent concentration became close to 13% by weight, it was peeled from the polyester film. And then temperature 1
In a drying oven at 30 ° C., the residual solvent concentration was dried to 0.07% by weight while balancing the vertical and horizontal tensions.

The film thus obtained has a thickness of 10
The film thickness unevenness in the width direction was 1 μm and ± 2 μm. The haze value of the film is 0.5 as measured by a haze meter.
%Met. Further, the dimensional stability was 0.02% after heat treatment at 120 ° C. for 1 hour and 0.07% after heat treatment at 150 ° C. for 30 minutes. The retardation value at 590 nm was 7 ± 2 nm in the width direction, the slow axis was oriented in the MD direction, and the variation was ± 7.5 degrees.

Further, a primer layer and a barrier coat layer were formed on both sides of the film. At that time, as the primer layer, a coating liquid obtained by diluting trade name “PC7A” manufactured by Shin-Etsu Chemical with a mixed solvent of 1/1 of methyl isobutyl ketone and n-butyl acetate was used. As the barrier coat layer, polyvinyl alcohol resin (trade name "PVA-117" manufactured by Kuraray) is sufficiently washed with hot water to remove sodium acetate contained as an impurity to a ppm level, and then purified water The coating liquid dissolved in was used. The primer layer was a Meyer bar coater, and the barrier coat layer was a reverse roll coater, and coating and drying were performed continuously (drying temperature was 130 ° C.). This gives a thickness of 0.5 μm
And a barrier coat layer having a thickness of 3 μm were laminated on both sides of the polycarbonate film.

Then, a hard coat layer was formed on the surface of one barrier coat layer. At that time, a coating liquid obtained by diluting the trade name “NS-2451” manufactured by Nippon Seika Co., Ltd. with isopropyl alcohol was used as a hard coating agent. This coating liquid is applied and dried by a reverse roll coater (drying temperature: 135
C.) to form a hard coat layer having a thickness of 8 μm.

A primer layer was formed on the surface of the other barrier coat layer. That is, a product name "Atron NSi" manufactured by Nippon Soda Co., Ltd. was diluted with isopropyl alcohol and coated and dried by using a micrograb coater to form a primer layer having a thickness of 60 nm.

Further, an indium-tin oxide thin film layer which is a transparent conductive thin film was formed on this primer layer by sputtering. Therefore, an indium-tin oxide target (molar ratio of indium / tin = 90/10, packing density of 90%) was used as the sputtering target. And set the film on the continuous sputtering device,
Ar / O ₂ = 9 after exhausting to a pressure of 1.3 mPa
A mixed gas having a mixing ratio of 8.5 / 1.5 was introduced to set the atmospheric pressure to 0.27 Pa. Then, the substrate temperature was set to 60 ° C., and DC sputtering was performed at an input power density of 1 W / cm ² . The resulting transparent conductive thin film had a film thickness of 30 nm and a surface resistance value of 250 Ω / □.

From the liquid crystal display panel electrode substrate thus obtained, first, two 5 cm square samples were cut out. Then, one of the liquid crystal display panel electrode substrate samples was set with its MD direction aligned with one of the optical axes of a pair of polarizing plates whose optical axes were orthogonal to each other. Further, another sample of the electrode substrate for liquid crystal display panel was sandwiched between the polarizing plates, and each of the sample and the polarizing plate was rotated in order to search the coloring position. The color change was visually observed, but no change occurred. Further, when heat treatment was performed at 140 ° C. for 2 hours, no change in curl (change in warp) and no change in appearance occurred.

Next, from the electrode substrate for the liquid crystal display panel,
Two 7 cm square samples were cut out. Then, Hitachi Chemical Co., Ltd. trade name “STX-24”, which is a low temperature curable polyimide as an aligning agent, was diluted and dissolved in N-methylpyrrolidone and spin-coated on each of the two samples. Subsequently, these were cured at 140 ° C. for 2 hours, and then rubbed 15 times using a polyester rubbing roll in a rubbing machine. After that, Sekisui Fine Chemical's trade name "Micropearl" was sprayed as a spacer. After that, the product name "Araldite" was screen-printed as a sealing agent.

Then, the two samples processed in this way were bonded and cured at 170 ° C. for 2 hours while applying pressure to prepare a liquid crystal cell. The cell gap of this liquid crystal cell was 6 μm as measured by the capacitance capacitance method.
Met. And from the opening of the sealant of this liquid crystal cell,
Asahi Denka product name "Kiracor 622"
8 ”was injected using a liquid crystal injection device. After the injection, the liquid crystal material was heated to the liquid crystal phase transition temperature and then gradually cooled to room temperature to complete the alignment. Regarding the orientation, it was confirmed that the liquid crystal was in STN orientation of 180 degrees by adhering the substrates in an orientation of 180 degrees.

The cell obtained as a result has a uniform color tone and has an ON response of 60 ms at an applied voltage of 1.8V.
The ec, OFF response was 25 msec, and it was confirmed that the response of the STN liquid crystal cell was shown.

[0054]

Comparative Example 1 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 such a film is about 30 nm as an average value in the width direction,
The variation of the slow axis angle was ± 20 degrees.

The same processing as shown in Examples was performed on this film to obtain an electrode substrate for a liquid crystal display panel. As a result of performing the same evaluation as that of the example, coloration that can be visually recognized was generated as the substrate was rotated, and at the same time, curling with a convex indium-tin surface was caused by heat treatment, and handling became difficult.

Further, the liquid crystal substrate was tried to be made into a liquid crystal cell by the same process as in the embodiment, but the substrate was significantly curled by the heat treatment after the polyimide coating, and it was impossible to continue the subsequent steps of the liquid crystal cell assembly. It was

[0057]

[Comparative Example 2] A polycarbonate resin having an average molecular weight of 24,000 and containing only bisphenol A as a bisphenol component was dissolved in methylene chloride to prepare a solution having a concentration of 22% by weight. The prepared solution is 20 ℃ in temperature and 60 in humidity
The solution is cast on a polished stainless steel belt by a casting method using a die in an environment of% RH, and then sequentially dried to remove the solvent from the stainless steel belt when the residual solvent is 14% by weight, and the temperature is set to 135 ° C. Dried. However, the haze value of the obtained film was 8%, and it could not be used as a film for this purpose.

[0058]

INDUSTRIAL APPLICABILITY As described in detail above, the present invention reduces the birefringence of a polymer film used for a liquid crystal display panel substrate, improves mechanical properties, improves dimensional stability and heat resistance, and improves glass properties. A film substrate for a liquid crystal display panel having the same display quality as when a substrate is used can be obtained by a method which is sufficiently cost competitive as compared with a glass substrate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoshi Jo, 4-3-2 Asahigaoka, Hino City, Tokyo Teijin Limited Tokyo Research Center

Claims (9)

[Claims] 1. An average molecular weight 3 of a bisphenol A copolymer obtained by copolymerizing a bisphenol component having a perhydroisophorone skeleton or a fluorene skeleton with bisphenol A at a copolymerization ratio of 5 to 30 mol%.
A film substrate for a liquid crystal display panel, comprising a polymer film of aromatic polycarbonate having a glass transition temperature of 0000 or more and a glass transition temperature of 160 ° C. or more as a substrate. 2. An average molecular weight of 30,000 or more and a glass transition temperature of 160, which is composed of a bisphenol A copolymer obtained by copolymerizing terephthalic acid, isophthalic acid or a mixture thereof with bisphenol A at a copolymerization ratio of 5 to 45 mol%. A film substrate for a liquid crystal display panel, characterized in that a polymer film of aromatic polyester carbonate having a temperature of ℃ or higher is used as a substrate. 3. A copolymer of bisphenol A obtained by copolymerizing a bisphenol component having a perhydroisophorone skeleton or a fluorene skeleton, and terephthalic acid or isophthalic acid or a mixture thereof with bisphenol A at a copolymerization ratio of 5 to 30 mol%. A film substrate for a liquid crystal display panel, comprising a polymer film of an aromatic polyester carbonate made of a polymer and having an average molecular weight of 30,000 or more and a glass transition temperature of 160 ° C. or more as a substrate. 4. The polymer film used as the substrate is
4. The liquid crystal display panel according to claim 1, wherein the retardation value is 15 nm or less, the variation of the slow axis is ± 10 degrees or less, and the haze value is 0.6% or less. Film substrate. 5. The polymer film used as the substrate is
The film is formed by a solution casting method.
A film substrate for a liquid crystal display panel according to any one of 1. 6. The polymer film used as the substrate is
The film substrate for a liquid crystal display panel according to claim 1, wherein the residual solvent concentration is 0.3% by weight or less. 7. The polymer film used as the substrate is
After heat treatment at 120 ° C. for 1 hour, the dimensional stability of the film is 0.05% or less in both the flow direction and the width direction, and 1
The film for liquid crystal display panel according to any one of claims 1 to 6, wherein the film has a dimensional stability of 0.1% or less in each of a flow direction and a width direction after heat treatment at 50 ° C for 30 minutes. substrate. 8. The polymer film used as the substrate is
The film substrate for a liquid crystal display panel according to any one of claims 1 to 7, wherein the thickness is 70 to 200 µm and the thickness unevenness is within ± 5%. 9. The polymer film used as the substrate is
9. The film according to claim 1, wherein the film is subjected to a barrier process for preventing the invasion of oxygen and water, a solvent resistance process having a cross-linked structure by a hard coat process, and a transparent electrode process. A film substrate for a liquid crystal display panel as described above.