JP3602555B2 - Liquid crystal display - Google Patents

Description

[0001]
[Industrial applications]
The present invention has excellent wet heat resistanceLiquid crystal displayAbout.
[0002]
[Prior art]
Liquid crystal display devices are frequently used in word processors, personal computers, color liquid crystal televisions, and the like. In recent years, liquid crystal display devices have been increasingly used under high temperature and high humidity conditions for use in vehicles and outdoors. In order to improve the reliability of a liquid crystal display device in a high-temperature, high-humidity atmosphere, a polarizing film having high moisture-heat resistance is strongly demanded. Recently, black-and-white display or color display of a liquid crystal display element is becoming common. In order to cope with such a display, there is a demand for a polarizing film which is excellent in wet heat resistance and has a high transmittance and a high degree of polarization.
[0003]
Conventionally, a polarizing film used for a liquid crystal display device or the like is produced by adsorbing a dichroic dye on a stretched and oriented polarizing film base film. As a polarizing film, a film which is optically transparent and has no anisotropy on both surfaces is generally used as a protective film. As a protective film, a triacetyl cellulose film (hereinafter sometimes referred to as a “triacetate film”) is used. As the base film of the polarizer, a polyvinyl alcohol-based polymer is generally used. The general method of making a polarizing film is to adsorb iodine on a stretched polyvinyl alcohol-based film, treat it with a fixed aqueous solution containing boric acid, and then attach a protective film consisting of a triacetate film to both sides of the polarizer. It is. As a general method for producing a dye-based polarizing film, a method of adsorbing a dichroic dye on a uniaxially stretched film is used. As the polymer film used in this case, a polyvinyl alcohol-based film is suitably used. In particular, a polarizing film in which iodine is adsorbed on a polyvinyl alcohol-based film is the most excellent in terms of transmittance and degree of polarization, and is most commonly used as a polarizing film.
[0004]
Also in conventional polarizing films, provision of a moisture-proof protective layer on the surface of a triacetate film has been studied in order to improve moisture-heat resistance. Examples of the moisture-proof protective layer used here include a coat layer of a polymethyl methacrylate resin (hereinafter abbreviated as “PMMA”), a polyester resin, or the like;₂And the like.
However, it is difficult to form a thin and uniform coat of the PMMA coat. If the thickness of the coat layer is increased in order to enhance the moisture resistance, the PMMA coat layer may be cracked. In addition, there is a problem that the adhesion between the PMMA coat layer and the triacetate film is weak.
When a polyester resin is used for the coating layer, the same trouble as when the PMMA is used for the coating layer occurs, and in addition, there is a practical problem as a polarizing film, such as a decrease in light transmittance or generation of interference fringes. .
The method using an inorganic vapor-deposited film is not a preferable method because cracks occur in the inorganic vapor-deposited film due to a large difference in expansion coefficient between the triacetate film and the inorganic vapor-deposited film with respect to heat or moisture. In addition, since the triacetate film has a high water absorption, it is extremely difficult to deposit an inorganic substance.
[0005]
[Problems to be solved by the invention]
The polyvinyl alcohol-based polarizing film has a problem of poor wet heat resistance. For example, when the moist heat resistance in an atmosphere of 80 ° C. and 90% relative humidity (RH) is tested with a polarizing film on which iodine is adsorbed (both sides of a polarizer are protected with a triacetate film), the polarizing film is in a crossed Nicols state (Polarization degree before standing 99.9%) and observed under the above conditions. As a result, the polarization degree decreased to 75% in 100 hours, and further decreased to 1.8% in 250 hours. . As shown in the above results, the resistance to moist heat of the conventional polarizing film was extremely poor. Also, various methods have been proposed as described above in order to improve the moist heat resistance of the polarizing film. However, these methods have various problems.
The present invention solves such problems and has excellent polarization characteristics and wet heat resistance.Liquid crystal displayThe purpose is to provide.
[0006]
[Means for Solving the Problems]
The present inventionPersonAs a result of intensive studies to solve the above problems, a polarizing film in which a transparent protective film is bonded to both sides of a polarizer having a dichroic dye adsorbed and oriented on a polyvinyl alcohol-based base filmLCD device bonded to both sides of a glass cell with liquid crystalAt(1) Polarizing filmUse a non-oriented triacetate film as a protective film on one side and a protective film on the other sideSurface treated by corona discharge treatment or plasma treatment in vacuumUse a film made of polycarbonate resin or a film made of polymethyl methacrylate resin.(2) a liquid crystal display device in which the surface of the polarizing film on the triacetyl cellulose film side is bonded to a glass cellAnd completed the present invention.
[0007]
The present inventionAtPolarizing filmIs thatTriacetate filmsurface(Polycarbonate resin film or polymethyl methacrylate resin film is provided outside the polarizer).
The present inventionAtLCD with polarizing filmToWhen used, a usage method as shown in FIG. 1 is used. That is, when two polarizing films are installed above and below a glass cell in which liquid crystal is sealed, both polarizing films are installed so that the polycarbonate-based resin film or the polymethyl methacrylate-based resin film does not face the glass surface.
[0008]
The polycarbonate resin film or the polymethyl methacrylate resin film used in the present invention is a film having birefringence, but has a polycarbonate resin film or a polymethyl methacrylate resin film by being installed outside the polarizer. Birefringence has no adverse effect on the liquid crystal display device. Therefore, the polycarbonate resin film or the polymethyl methacrylate resin film used in the present invention may have any value of the birefringence, and the uniformity of the birefringence does not matter.
The present inventionInPolarizing filmButCompared to conventional polarizing films (polyvinyl alcohol-based polarizers with protective films of triacetate films on both sides), the reason that the heat and humidity resistance is significantly superior is that polycarbonate-based resin films or polymethyl methacrylate-based resin films It is presumed that this is because the water absorption of the triacetate film is significantly lower than that of the triacetate film. Due to the low water absorption, the permeability of water through the film is low, which is the present invention.Liquid crystal displayThis is considered to be the reason for increasing the moist heat resistance of. In the present invention, since the triacetate film as the other protective film is provided on the glass surface side, there is almost no invasion of moisture from this surface.
[0009]
The method for producing the polycarbonate resin film or the polymethyl methacrylate resin film used in the present invention is not particularly limited. That is, any of a film by an extrusion method, a film by a solvent casting method, a film by a calender method, and the like may be used. In the present invention, a uniaxially stretched film or a biaxially stretched film may be used, but these films are not preferred because they tend to have poor surface accuracy as compared with a film immediately after extrusion. Most preferred films are extruded films. Extruded film is good because it can be produced at a low price.
[0010]
The film made of the polycarbonate resin used in the present invention has a glass transition point (Tg) of 110 ° C. or more and a water absorption (value measured in water at 23 ° C. for 24 hours) of 0.3% or less. Good to use things. More preferably, those having a Tg of 120 ° C. or more and a water absorption of 0.2% or less are preferably used.
The film made of polymethyl methacrylate resin used in the present invention has a glass transition point (Tg) of 90 ° C. or more and a water absorption (value measured in water at 23 ° C. for 24 hours) of 0.5%. The following should be used: More preferably, those having a Tg of 95 ° C. or more and a water absorption of 0.3% or less are used.
[0011]
The film made of the polycarbonate resin used in the present invention may be used by being mixed with another transparent resin such as a polystyrene resin or a PMMA resin. Further, the film made of polymethyl methacrylate resin used in the present invention may be used by mixing with another transparent resin such as polybutyl acrylate resin which improves impact resistance. When used in combination with another transparent resin, it is necessary to prevent the transparency from being lowered by mixing. When mixed with another resin, it is preferable that 50% by weight or more be a polycarbonate resin or a polymethyl methacrylate resin. That is, the mixing amount of the other resin is preferably 5% by weight or more and less than 50% by weight. When the mixing ratio of the polycarbonate resin or the polymethyl methacrylate resin is less than 50% by weight, the high heat resistance and good film strength of the polycarbonate resin may be lost, and the polymethyl methacrylate resin has High transparency may disappear.
[0012]
The polycarbonate resin used in the present invention is mainly a linear polycarbonate having a bisphenol skeleton or a copolymerized polycarbonate. Specifically, it can be obtained from 4,4'-dihydroxydiphenylalkane or a halogen-substituted product thereof by a phosgene method or a transesterification method. More specifically, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylethane, 4,4'-dihydroxydiphenylbutane and the like can be mentioned. The polymethyl methacrylate resin used in the present invention is a polymer containing methyl methacrylate (hereinafter abbreviated as MMA) as a main component, and contains PMMA, a copolymer containing MMA units, and PMMA or MMA units. A blend of a copolymer and another polymer can be used.
As the copolymer containing MMA units, a copolymer of MMA and an alkyl acrylate can be favorably used. As the alkyl acrylate, a copolymer obtained by copolymerizing 1 to 30% by weight of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and the like can be used. A heat-resistant acrylic resin such as an MMA-maleic anhydride-styrene terpolymer and an MMA-methyl methacrylamide copolymer can also be used. A copolymer containing various additives may be used for the copolymer containing PMMA or MMA units. As various additives to be added to the polymethyl methacrylate-based resin, it is preferable to add an ultraviolet absorber (ultraviolet ray inhibitor) and the like.
[0013]
As the adhesive used to bond the polarizer to the film made of the polycarbonate resin or the film made of the polymethyl methacrylate resin, a polyvinyl alcohol-based adhesive is preferably used. When the protective film and the polarizer are adhered to each other, it is not preferable that the adhesive layer is provided independently because there is a possibility that reflected light may increase and interference fringes may occur due to the presence of two interfaces. By matching the refractive index of the adhesive layer to a film made of a polycarbonate resin or a film made of a polymethyl methacrylate resin, the presence of the adhesive layer can be optically eliminated, but the polycarbonate resin film usually has a birefringence. It is difficult to select an adhesive that also takes into account the birefringence because of having a polymethyl methacrylate-based resin film. could not. For such a reason, it is preferable to use a polyvinyl alcohol-based adhesive as the adhesive.
[0014]
When a film made of a polycarbonate resin or a film made of a polymethyl methacrylate resin is bonded to a polarizer using a polyvinyl alcohol-based adhesive, a film made of a polycarbonate resin or a film made of a polymethyl methacrylate resin is used. There is a problem that the adhesiveness to the surface is poor. To improve this point, increase the adhesiveness by mixing another transparent resin with the polycarbonate resin or polymethyl methacrylate resin, or use a corona film on the polycarbonate resin film or the polymethyl methacrylate resin film. It is preferable to improve the adhesion by performing a surface treatment such as a discharge treatment or a plasma treatment in a vacuum. By subjecting the film to a surface treatment, the adhesion to the polarizer can be significantly improved. Further, it is preferable that a film of a mixture of a polycarbonate-based resin and a polymethyl methacrylate-based resin is subjected to a surface treatment because the adhesion to a polarizer is improved.
[0015]
Polymethyl methacrylate-based resin used for mixing with polycarbonate-based resin is a polymer mainly composed of methyl methacrylate, but acrylate, cyclohexyl methacrylate, methacryl to improve adhesiveness with polycarbonate-based resin. It is preferably used as a copolymer with tribromophenyl acid or the like.
[0016]
The thickness of the film made of the polycarbonate resin used in the present invention is preferably 10 μm or more and 300 μm or less. It is more preferable that the thickness be 40 μm or more and 120 μm or less. When the thickness of the film is small, the performance for maintaining the dimensions of the polarizer is deteriorated, which is not preferable. On the other hand, if the thickness is too large, the obtained polarizing film becomes too hard, which is not preferable.
The thickness of the film made of polymethyl methacrylate resin used in the present invention is preferably 10 μm or more and 2 mm or less. More preferably, the thickness is 40 μm or more and 1.2 mm or less. When the thickness of the film is small, the performance for maintaining the dimensions of the polarizer is deteriorated, which is not preferable. On the other hand, if the thickness is too large, the obtained polarizing film is too hard, which is not preferable. When the thickness of the polymethyl methacrylate-based resin film is 0.4 mm or more, the polymethyl methacrylate-based resin film serves as a protective plate for the polarizer and at the same time functions as a protective plate for the crystal display element itself. .
[0017]
In the present invention, a triacetate film must be used as the other protective film. The triacetate film is required to be optically transparent and to evaporate water used in bonding a film made of a polycarbonate resin to a polarizer. Adhesion between the polarizer and the triacetate film uses a polyvinyl alcohol-based adhesive.
[0018]
The present inventionAtThe polarizing film is used by adhering to the glass surface of the liquid crystal display device, and an acrylic adhesive is preferably used as the adhesive used when adhering to the glass surface.
[0019]
Examples of the polyvinyl alcohol-based film used for the polarizer in the present invention include a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, a polyvinyl butyral film, and a saponified ethylene-vinyl acetate copolymer film.
The polyvinyl alcohol base film preferably has a degree of saponification of the resin constituting the film of 85% or more. Particularly preferably, it is 90% or more, and most preferably, it is 95% or more. If it is less than 85%, the stretchability and the dyeability are inferior.
[0020]
The dichroic dye used in the present invention is not particularly limited as long as it has two or more optical axes having different absorption coefficients in the visible light region in the molecule. For example I₃ ⁻, I₅ ⁻And dichroic dyes such as Congo Red, polyene and the like. Alternatively, these may be used in combination. Among them, iodine is preferable because a polarizing film having a high degree of polarization and a high transmittance can be obtained.
[0021]
In the present invention, the dichroic dye may be dyed after uniaxially stretching the polyvinyl alcohol-based film, or the film before stretching may be dyed in advance with the dichroic dye and then uniaxially stretched. The adsorption of the dichroic dye into the polyvinyl alcohol-based film is performed, for example, by immersing the polyvinyl alcohol-based film in a liquid containing the dichroic dye. Examples of the liquid that dissolves the dichroic dye include water and ethanol. , Methanol, ethylene glycol and a mixed solvent thereof are preferably used. The dichroic dye is preferably used at a concentration of 0.05% to 5%.
[0022]
The dichroic dye solution preferably contains a crosslinking agent. After the dichroic dye is adsorbed on the polyvinyl alcohol-based film, the treatment may be performed in a solution containing a crosslinking agent. As a crosslinking agent used in this case, boric acid, borax, a zirconium compound or the like is used. The temperature at which the dichroic dye is adsorbed and cross-linked by the cross-linking agent is preferably 30 to 110 ° C.
[0023]
A specific example in the present invention will be described using a polyvinyl alcohol film. The present inventionAtThe polarizer of the polarizing film is obtained by stretching an unstretched film of polyvinyl alcohol 3 to 6 times in water, then immersing the film in an aqueous solution of potassium iodide containing iodine, and further treating in an aqueous solution of boric acid containing potassium iodide. Can be obtained. Further, it can be obtained by immersing an unstretched film of polyvinyl alcohol in an aqueous solution of potassium iodide containing iodine, stretching the unstretched film 3 to 6 times in the aqueous solution, and treating the film in an aqueous solution of boric acid containing potassium iodide.
Protective layers are formed on both sides of the obtained polarizer to obtain a polarizing film.
[0024]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples.
Reference example
30 parts of polyvinyl alcohol having a polymerization degree of 1900 and a saponification degree of 99.5% was dissolved in 70 parts of water to obtain a solution having a polyvinyl alcohol concentration of 30% by weight. This solution was cast on a polyethylene terephthalate film and dried to obtain a raw polyvinyl alcohol film having a thickness of 75 μm.
[0025]
Example 1
The 75 μm-thick raw film of polyvinyl alcohol obtained in Reference Example was immersed in water and then stretched uniaxially 5 times in a longitudinal direction. While maintaining the tension of the film, the film was immersed in an aqueous solution containing 0.5% by weight of iodine and 5% of potassium iodide to adsorb the dichroic dye. Further, a cross-linking treatment was performed for 5 minutes with a 50 ° C. aqueous solution composed of 10% boric acid and 10% potassium iodide. This cross-linking treatment was performed under tension. Thus, a polarizer was obtained.
[0026]
A polycarbonate resin having a thickness of 80 μm was extruded at 280 ° C. from a Teflon A3000 polycarbonate resin manufactured by Idemitsu Petrochemical Co., Ltd. The water absorption of this film was 0.09% (measured in water at 23 ° C. for 24 hours). The Tg of the resin was 137 ° C. This film was subjected to a corona discharge treatment.
[0027]
The above-mentioned polycarbonate film was bonded to one surface of the polarizer using a polyvinyl alcohol-based adhesive. Water was used as a solvent for the adhesive. An 80 μm-thick triacetylcellulose film (Fuji Photo Film Co., Ltd., Fujitac) was bonded to the other side of the polarizer using a polyvinyl alcohol-based adhesive. Thus, a polarizing film was obtained.
[0028]
The single transmittance of this polarizing film was 39%, and the degree of polarization was 99.9%. When the cross section of this polarizing film was observed using an optical microscope, no adhesive layer was observed, and the polarizing film had a substantially three-layer structure. (2 layers of protective film, 1 layer of polarizer).
[0029]
An acrylic pressure-sensitive adhesive was applied to the surface of the triacetyl cellulose film and adhered to a glass plate. The moisture-heat resistance was evaluated in such a state.
[0030]
The relationship between the standing time in an atmosphere of 80 ° C. and 90% RH and the degree of polarization when the polarizing film was placed in a crossed Nicols state was measured. The initial polarization was 99.9%. After standing for 200 hours, the degree of polarization dropped to 99.0%. The relationship between the standing time and the degree of polarization is shown by the solid line 1 in FIG. The test was stopped at this point because the polycarbonate film and the polarizer peeled off 270 hours after standing.
[0031]
The transmittance was measured according to the Japan Electronic Machinery Industry Standard (LD-201) (calculated from the spectral transmittance measured every 10 nm in a wavelength range of 400 nm to 700 nm).
The degree of polarization is a value obtained from the following equation.
Degree of polarization = [(H₁-H₂) / (H₁+ H₂)]^1/2
H₁Parallel transmittance (transmittance when the orientation directions of the two polarizing films are set to be the same direction)
H₂Vertical transmittance (transmittance when the orientation directions of two polarizing films are orthogonal)
[0032]
Comparative Example 1
A polarizing film was produced in the same manner as in Example 1 except that a triacetyl cellulose film was used on both sides. The single transmittance of this polarizing film was 40%, and the degree of polarization was 99.9%. The polarizing film was bonded to a glass plate using an acrylic pressure-sensitive adhesive in the same manner as in Example 1. In such a state, the wet heat resistance in an atmosphere of 80 ° C. and 90% RH was evaluated.
Initially, the degree of polarization was 99.9%, but after 100 hours the degree of polarization dropped to 75%. After 250 hours of standing, the degree of polarization decreased to 1.8%. At this point the test was stopped. The relationship between the standing time and the degree of polarization is shown by the broken line 3 in FIG. The wet heat resistance was significantly inferior to the case where a film made of a polycarbonate resin was used.
[0033]
Example 2
80% by weight of the polycarbonate resin Tafflon A3000 used in Example 1 and 20% by weight of PMMA resin L-16 (copolymer of methyl methacrylate and tribromophenyl methacrylate) manufactured by Kuraray Co., Ltd. at a temperature of 280 ° C. Mix evenly. The resulting mixture was completely transparent. This resin was extruded from a T-die at a temperature of 280 ° C. to obtain a transparent film having a thickness of 80 μm. The water absorption of this film was 0.17%. This film was subjected to a corona discharge treatment.
[0034]
A polarizing film was produced in the same manner as in Example 1 except that the above-mentioned film was used. The single transmittance of this polarizing film was 39%, and the degree of polarization was 99.9%. Observation of the cross section of the polarizing film revealed that it had a substantially three-layer structure.
An acrylic pressure-sensitive adhesive was applied to the surface of the triacetyl cellulose film and adhered to a glass plate. In this state, evaluation of wet heat resistance was performed in the same manner as in Example 1.
The initial polarization was 99.9%. After standing for 200 hours, the degree of polarization dropped to 99.0%. The degree of polarization decreased to 98.2% after standing for 400 hours and to 96.2% after standing for 1000 hours. The test was stopped at 1000 hours. This result is shown in FIG. There was no peeling between the polycarbonate film and the polarizer.
[0035]
ComparisonAn example2
Granulation was performed by mixing 25% by weight of polyethyl acrylate with 75% by weight of a copolymer composed of 97% by weight of methyl methacrylate and 3% by weight of butyl acrylate. The softening temperature of this mixed resin was 98 ° C., and the Tg was 105 ° C.
This resin was extruded from a 300 mm wide T-die using a 60 mmφ screw extruder at a cylinder temperature of 250 ° C. and a die temperature of 250 ° C. to obtain a 0.8 mm thick film made of PMMA resin. This raw film was subjected to bank molding with a pair of pressure rolls at 230 ° C. to obtain a film having a good appearance and a thickness of 0.5 mm. The water absorption of this film was 0.2% (measurement was performed in water at 23 ° C. for 24 hours).
A film made of the above-mentioned PMMA-based resin was bonded to one surface of the polarizer obtained in Example 1 using a polyvinyl alcohol-based adhesive. Water was used as a solvent for the adhesive. To the other side of the polarizer, triacetyl cellulose (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was bonded using a polyvinyl alcohol-based adhesive. Thus, a polarizing film was obtained.
The single transmittance of this polarizing film was 40%, and the degree of polarization was 99.9%. When the cross section of this polarizing film was observed using an optical microscope, no adhesive layer was observed, and the polarizing film had a substantially three-layer structure (two protective films and one polarizer).
An acrylic pressure-sensitive adhesive was applied to the surface of the triacetyl cellulose film and adhered to a glass plate. The moisture-heat resistance was evaluated in such a state.
It was left in an atmosphere of 80 ° C. and 90% RH, and the relationship between the standing time and the degree of polarization was measured. The initial polarization was 99.9%. The relationship between the standing time and the degree of polarization was the same as in Example 1. Up to 200 hours after standing, a high degree of polarization was exhibited. However, the test was stopped at this point because the PMMA-based film and the polarizer peeled off 220 hours after standing.
[0036]
Example3
ComparisonAn example2Plasma treatment was performed to hydrophilize the surface of the 0.5 mm-thick PMMA-based resin film obtained in the above. The processing gas used was oxygen. Surface treatment with oxygen plasma was performed under the conditions of an oxygen flow rate of 27 liter / hr, a degree of vacuum of 0.15 torr, a voltage of 9000 V, and a treatment time of 180 seconds. This treatment increased the wetting index of the film surface to 54 (dyne / cm). Considering that the wetting index before the treatment was 39 (dyne / cm), the hydrophilicity of the surface of the PMMA-based resin film was greatly improved by the plasma treatment.
Except for using this filmComparisonAn example2A polarizing film was obtained in the same manner as described above. The moisture and heat resistance of this polarizing filmComparisonAn example2It was measured in the same manner as described above. The relationship between the standing time and the degree of polarization was the same as in Example 2. This polarizing film maintained a good degree of polarization even after 1000 hours of standing.
[0037]
【The invention's effect】
As described above, the present inventionAtSince the polarizing film uses a polycarbonate resin film or a polymethyl methacrylate resin film as a protective film on one side, a conventional polarizing film (a triacetyl cellulose film was provided as a protective film on both sides of a polyvinyl alcohol polarizer). ) Is much more excellent in wet heat resistance than that of
[Brief description of the drawings]
FIG. 1 is an explanatory view in which two polarizing films of the present invention are installed on a surface of a liquid crystal display device covered with a glass plate.
FIG. 2 is a graph showing the relationship between the polarization time when a polarizing film is left in an atmosphere of 80 ° C. and 90% RH and the polarizing film is placed in a crossed Nicols state.
[Explanation of symbols]
a: Polycarbonate resin film or polymethyl methacrylate resin film
b: Polarizer
c: Triacetyl cellulose film
d: Adhesive layer
e: Glass plate
f: liquid crystal
1: polarizing film obtained according to Example 1
2: Polarizing film obtained according to Example 2
3: Polarizing film obtained according to Comparative Example 1

Claims (3)

The polarizing film of polyvinyl alcohol substrate film dichroic dye bonding the transparent protective film on both surfaces of a polarizer is adsorbed and oriented, in the liquid crystal display device adhered to both surfaces of the glass cell in which liquid crystal sealed, (1 ) and one side of the protective film is a triacetyl cellulose film of the polarizing film, Ri film der protective film on the other side is made of surface-treated polycarbonate resin by plasma treatment with a corona discharge treatment or in a vacuum, ( 2) A liquid crystal display device in which the surface of the polarizing film on the triacetyl cellulose film side is bonded to a glass cell . 2. The liquid crystal display device according to claim 1, wherein the film made of a polycarbonate resin is a film of a mixed resin of a polycarbonate resin and a polymethyl methacrylate resin. The polarizing film of polyvinyl alcohol substrate film dichroic dye bonding the transparent protective film on both surfaces of a polarizer is adsorbed and oriented, in the liquid crystal display device adhered to both surfaces of the glass cell in which liquid crystal sealed, (1 ) and one side of the protective film is a triacetyl cellulose film of the polarizing film, Ri film der protective film on the other side is formed of polymethyl methacrylate resin which has been surface treated by plasma treatment with a corona discharge treatment or in a vacuum, (2) A liquid crystal display device in which the surface of the polarizing film on the triacetyl cellulose film side is bonded to a glass cell .

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