JP3446739B2 - Optical film and liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optical film used in a liquid crystal display device and the like and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Liquid crystal display devices are being used in portable televisions, notebook personal computers and the like because of their features such as light weight, thin shape and low power consumption. Currently, the main adoption is TN driven by active matrix.
Type liquid crystal display device (hereinafter referred to as AM-TN-LCD),
Simple matrix drive FTN type liquid crystal display device (hereinafter,
It is referred to as SM-FTN-LCD). AM-TN-
Liquid crystal display devices such as LCD and SM-FTN-LCD are
There is a problem that the viewing angle characteristics such as a decrease in contrast and a change in hue when viewed from an oblique direction are not sufficient. This viewing angle characteristic is mainly due to the angle dependency of the retardation of the liquid crystal cell and the retardation of the retardation film when the retardation film is used.

In order to improve this viewing angle characteristic, studies have been made to improve the angle dependence of the retardation of the retardation film, but it has not been sufficiently improved, and therefore, JP-A-H07-76107.
There is also a study on improvement of viewing angle characteristics using a light control plate as disclosed in Japanese Patent Laid-Open No. 64069. Also, S
M-FTN-LCD has a problem that contrast and response speed are low compared to AM-TN-LCD, but as a method of improving this, a liquid crystal cell using a liquid crystal having a large birefringence is used. There is known a method for reducing the cell gap of the. However, a liquid crystal having a large birefringence generally has a large wavelength dependence of the birefringence, and if the wavelength dependence of the birefringence of the retardation film used together with this liquid crystal is not compatible with the liquid crystal, the contrast It causes problems such as lowering. To solve this, it is effective to use a retardation film having a wavelength dependency of the birefringence larger than that of the conventional method, and a method of obtaining a retardation film having a wavelength dependency of such a birefringence index is large, It is exemplified in Japanese Patent Application No. 6-282041 (= Japanese Patent Laid-Open No. 8-146220). However, these films do not always have sufficient improvement in viewing angle characteristics.

[0004]

As a result of extensive studies to solve the above problems, at least one light control plate,
It was found that a liquid crystal display device excellent in viewing angle characteristics can be obtained by using a film obtained by laminating at least one thermoplastic resin retardation film and a polarizing film, and completed the present invention. .

[0005]

That is, the present invention is as follows.
(A) At least one light control plate obtained by irradiating with ultraviolet rays after forming a composition containing two or more kinds of photopolymerizable monomers and / or oligomers having different refractive indexes into a film, ( (b) An optical film formed by laminating at least one retardation film made of a thermoplastic resin and (c) a polarizing film. In addition,
(In-plane retardation value) / (retardation value in the thickness direction), which is the object of Japanese Patent Application No. 7-98355 (= Japanese Patent Application Laid-Open No. 8-292321) relating to the applicant's earlier application.
This is excluded when a retardation film having a ratio of 0.5 to 1.8 is used.

Further, according to the present invention, at least one of the two glass substrates having the electrodes is transparent, has a positive dielectric anisotropy between the two glass substrates, and has a twist angle of 6 mm.
Provided is a liquid crystal cell in which a nematic liquid crystal layer having a degree of 0 to 120 degrees is arranged, and at least one of the optical films is arranged above and / or below the liquid crystal cell. At least one of the two glass substrates having the above is transparent, and a nematic liquid crystal layer having a positive dielectric anisotropy and a twist angle of 180 to 270 degrees is arranged between the two glass substrates. In the liquid crystal cell, there is also provided a liquid crystal display device in which at least one of the above optical films is arranged on the upper side and / or the lower side of the liquid crystal cell.

The light control plate used in the present invention is formed by using at least two kinds of photopolymerizable monomers and / or oligomers having mutually different refractive indexes.

Examples of these photopolymerizable monomers and oligomers include 2,4,6-tribromophenyl acrylate, tribromophenoxyethyl acrylate, as exemplified in JP-A-7-64069.
2-hydroxy-3-phenoxypropyl acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol acrylate, pentenyloxyethyl acrylate, phenyl carbitol acrylate, polyol polyacrylate, isocyanuric acid skeleton polyacrylate, melamine acrylate, hydantoin skeleton polyacrylate, Urethane acrylate etc. are mentioned.

As the photopolymerizable monomer and oligomer, two or more kinds having different refractive indexes are used. The combination is, for example, 2 kinds selected from monomers, 1 kind of monomer and 1 kind of oligomer, and 2 kinds selected from oligomer.
The species, or a combination thereof, to which one or more monomers or oligomers are further added. In these combinations, at least two of them have a refractive index difference of 0.
It is preferably 01 or more in order to obtain the required light scattering ability.

Further, in order to improve the curability of the above composition for a light control plate, it is preferable to use a photopolymerization initiator. As a photopolymerization initiator, JP-A-7-64069 can be used.
Benzophenone, 2-
Hydroxy-2-methylpropiophenone, benzyl,
Examples include Michler's ketone and 2-chlorothioxanthone.

The above composition for a light control plate may contain a compound having a refractive index different from that of a photopolymerizable monomer or oligomer and having no photopolymerization property. As such a compound having no photopolymerization property, polystyrene is used. Styrene resins such as, acrylic resins such as polymethylmethacrylate, resins such as polyethylene oxide, polyvinylpyrrolidone and polyvinyl alcohol, organic halogen compounds, organic silicon compounds, plasticizers, plastic additives such as stabilizers, and the like. . These are in the above resin composition for a light control plate,
It can also be blended as a high refractive index component or a low refractive index component. The difference in refractive index between at least one of the photopolymerizable monomer or oligomer and the compound having no photopolymerizable property is 0.0
1 or more is preferable.

Further, the average particle size is 0.05 μm to 20 μm.
It is also possible to add 0.01 to 5 parts by weight of the above-mentioned filler and to add an ultraviolet absorber.

The above composition is illustrated in JP-A-7-64069 and used in the examples of the present invention, as shown in FIGS. 1 and 2.
A light control plate that selectively scatters incident light having a specific angle can be obtained by curing with a light curing device as shown in FIG. Further, a thermosetting mechanism may be used in combination within a range that does not hinder performance expression. At the time of curing, it is preferable to apply these compositions onto a substrate, or to enclose the composition in a cell to form a film, and then irradiate the composition with ultraviolet rays from a specific direction to cure the composition. With this method, it is possible to obtain a light control plate that selectively scatters incident light having a desired angle.

The light source used in photopolymerization is not particularly limited as long as it emits ultraviolet rays that contribute to photopolymerization.
The shape of the light source is appropriately selected depending on the light control function required for the optical film of the present invention. As shown in Japanese Patent Application No. 6-3236 (= Japanese Patent Application Laid-Open No. 7-209637), in order to make the light-scattering ability of the light control plate equal in all directions, parallel rays such as sunlight are used. It is most preferable to use, but if the light source is spherical or box-shaped, and the ratio of the length of the lamp in the major axis direction to the length in the minor axis direction is 2: 1 or less, equivalent performance should be exhibited. You can A linear or rod-shaped light source is preferably used when the scattering characteristic is provided only in one direction such as the vertical direction or the horizontal direction.

The selective scattering power with respect to the light incident angle of the light control plate is defined by the haze value with respect to the light incident angle of the light control plate. The light control plate used in the present invention has a characteristic that the haze value changes depending on the light ray incident angle, and has a light ray incident angle region (scattering angle region) having a haze value of 30% or more and a light scattering ability other than that. Those having a light ray incident angle range having a valence of less than 30% and exhibiting no light scattering ability are preferable. The maximum haze value in the scattering angle region is preferably 30% to 85% from the viewpoint of display clarity.

The thickness of the light control plate of the present invention is required to be 10 μm or more in order to exhibit the light scattering ability, and it is appropriately determined so that the required light scattering ability can be obtained at a thickness of 10 μm or more, but it is from 50 μm to A thickness of 300 μm is preferably used.

The light control plate used in the present invention, as disclosed in the above-mentioned Japanese Patent Application No. 6-3236 (= JP-A-7-209637), contains a specific photopolymerizable monomer and / or Or, when the composition containing the oligomer is irradiated with ultraviolet rays, it is prepared by utilizing the property of photopolymerization and curing while causing phase separation.According to this method, without using a mask during the irradiation of ultraviolet rays, Domain spacing is 1μ
It is possible to manufacture a smooth refractive index modulation type light control plate of m to 20 μm. In this phase separation, since the interface is continuous, when light is transmitted through the obtained light control plate, reflection does not occur at the interface and the light transmittance is not reduced. Further, unlike the phase grating, this light control plate does not have a regular structure, so that moire fringes do not occur. Furthermore, since this light control plate can be manufactured only by the step of irradiating the film-shaped composition with ultraviolet rays without using a mask, the manufacturing method is simple and the mass productivity is excellent.

A polycarbonate resin film, a methacrylic resin sheet, a polyethylene terephthalate film, or the like can be used as a substrate to which the above composition is applied.

The retardation film made of a thermoplastic resin used in the present invention is not particularly limited, but it is disclosed in JP-A 2-4240.
A retardation film as described in Japanese Patent No. 6 can be used.

As the retardation film made of a thermoplastic resin, a retardation film made of a thermoplastic resin having a positive refractive index anisotropy is preferably used in terms of transparency and mechanical strength. As the thermoplastic resin having a positive refractive index anisotropy, a polycarbonate resin, a polysulfone resin, a polyarylate resin, a polyether sulfone resin, a polyester resin, a polyvinyl alcohol resin,
Cellulose resins and the like are preferably used. Further, the above-mentioned Japanese Patent Application No. 6-282041 (= JP-A-8-14662).
20), SM-FTN-L.
In the case of using a liquid crystal having a large birefringence for improving the response speed in CD, the wavelength dependence of the birefringence of the liquid crystal becomes large. In order to obtain high contrast, it is necessary to increase the wavelength dependence of the birefringence of the retardation film, that is, the wavelength dependence of the retardation. The wavelength dependence of the retardation is the ratio α [α = R (486) / R (589)] of the retardation value R (486) at the wavelength of 486 nm to the retardation value R (589) at the wavelength of 589 nm.
, SM-FTN-L with improved response speed
A retardation film having α of 1.07 or more is more suitable for CDs and the like, and is a conventional SM-FTN among the above resins.
-Polycarbonate resin (α =
1.06) compared with polysulfone resin (α = 1.0
9), polyether sulfone resin (α = 1.11) and the like are preferably used.

Further, polysulfone resin is the upper limit as a resin having a large α that can be produced by a mass production apparatus, but the above-mentioned Japanese Patent Application No. 6-282041 (= JP-A-8-1462).
No. 20), by using a method of laminating two oriented films having different α of 0.03 or more so that their slow axes are orthogonal to each other, α is 1.10 or more. It is also possible to produce a retardation film that is

The method for producing the retardation film made of the above-mentioned thermoplastic resin is not particularly limited, and a raw film formed by a solvent casting method or the like is stretched between rolls,
A uniaxial stretching method such as a tenter stretching method is used. When two oriented films having different α of 0.03 or more are laminated so that their slow axes are orthogonal to each other, the above-mentioned Japanese Patent Application No. 6-282041 (= JP-A-8-146220).
As shown in (Japanese Patent Publication No.), in order to reduce the angle dependence of the retardation, a vertical alignment film of a polymer liquid crystal is further laminated on the laminated film, or the alignment film is thermally relaxed to increase the retardation of the retardation. A method such as reducing the angle dependence can also be used.

The polarizing film used in the present invention is not particularly limited. A stretched polyvinyl alcohol film is dyed with iodine or a dichroic dye, and transparent films are attached to both surfaces as protective films. An iodine-based polarizing film dyed with iodine, which has high polarization performance when the durability is not so demanding, while a dichroic dye which has slightly lower polarization performance but is more durable when the durability is demanding. A dye-based polarizing film obtained by dyeing is used.

The optical film of the present invention can be obtained by laminating the above-mentioned light control plate, retardation film and polarizing film. The order of lamination is appropriately determined according to the required optical characteristics, but the polarizing film / light control plate / retardation film, light control plate / polarizing film / retardation film, polarizing film / retardation film / light control plate, etc. The structure of can be illustrated. Further, when a plurality of light control plates having a scattering property in one direction are used to provide the scattering properties in a plurality of specific directions, a polarizing film / light control plate / light control plate / retardation film, a light control plate It is also possible to adopt a structure such as / polarizing film / light control plate / retardation film. Further, when two retardation films are used, a structure such as a light control plate / polarizing film / retardation film / retardation film can be adopted.

The laminating method is not particularly limited, but
For example, a method of producing a light control plate, a retardation film and a polarizing film independently, and laminating with a pressure-sensitive adhesive or an adhesive, using a polarizing film as a substrate when producing a light control plate, and directly A method of laminating a control plate / polarizing film laminated structure with a retardation film using an adhesive or an adhesive can be used.

When the optical film of the present invention is arranged on the surface of a liquid crystal display device and used, an additional function can be imparted to the surface of the optical film. For example, a transparent protective film for preventing scratches may be attached to the surface of the outermost film, or a hard coat layer for preventing scratches may be provided. Further, in order to prevent reflection of external light, fine unevenness may be formed on the surface to form an anti-glare layer that diffusely reflects external light, or an antireflection layer formed of a multilayer film of dielectric thin films. Furthermore, a transparent protective film having an antireflection layer formed thereon may be attached, or the antireflection layer may be formed on the hard coat layer.

The method of laminating the optical film of the present invention on a liquid crystal cell is not particularly limited, and the laminated film having a constitution that can obtain the required display characteristics is provided on the upper side and / or the lower side of the liquid crystal panel with an adhesive. It may be pasted by using such as.

Regarding the lamination angle of the light control plate, the retardation film and the polarizing film used in the present invention to the liquid crystal panel, for example, the polarizing film and the retardation film have the same contrast and hue when viewed from the front of the liquid crystal panel. The angle between the absorption axis of the polarizing film and the slow axis of the retardation film viewed from the direction perpendicular to the film surface is set to the panel so that it is optimal. It is set so that the direction in which the corner characteristic is desired to be improved. Then, by laminating the light control plate, the retardation film and the polarizing film according to these set angles, the optical film of the present invention can be obtained.

[0029]

The optical film of the present invention has the functions of a light control plate, a retardation film and a polarizing film. By applying this optical film to a liquid crystal panel, a liquid crystal display device having excellent viewing angle characteristics can be obtained. be able to.

[0030]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.
The ratio α of the retardation value R (486) at the wavelength of 486 nm and the retardation value R (589) at the wavelength of 589 nm
[Α = R (486) / R (589)] was determined by measuring with a polarizing microscope using a ¼ wavelength plate corresponding to monochromatic light of 486 nm and 589 nm.

Example 1 To 40 parts of polyether urethane acrylate (refractive index 1.460) having an average molecular weight of about 6000 obtained by the reaction of polypropylene glycol, hexamethylene diisocyanate and 2-hydroxyethyl acrylate, 2,4,4 30 parts of 6-tribromophenyl acrylate (refractive index 1.576), 30 parts of 2-hydroxy-3-phenoxypropyl acrylate (refractive index 1.52)
6), and 1.5 parts of 2-hydroxy-2-methylpropiophenone as a photopolymerization initiator were added and mixed to prepare a photopolymerizable composition. This composition was applied to a polyethylene terephthalate film having a thickness of 188 μm, irradiated with ultraviolet rays at an irradiation angle of 17 degrees by the apparatus shown in FIGS. 1 and 2, and then peeled from the polyethylene terephthalate film to prepare a light control plate. did. In the figure, 1 is 80
A W / cm rod-shaped high-pressure mercury lamp, 2 a light-shielding plate, 3 a conveyor, 4 a polyethylene terephthalate film having a thickness of 188 μm coated with a composition for a light control plate, and 5 an ultraviolet irradiation angle in this example. The obtained light control plate had a thickness of 205 μm, a domain interval of 3 μm, a maximum haze value of 75%, and a scattering angle range defined by a haze value of 30% or more was 6 ° to 40 °.

A retardation film obtained by uniaxially stretching a solvent cast film of polycarbonate (trade name "Sumikalite").
SEF-360428 ", manufactured by Sumitomo Chemical Co., Ltd. was prepared (retardation = 380 nm, α = 1.06).

A 250 μm thick acrylic sheet (“Technoloy HG”, manufactured by Sumitomo Chemical Co., Ltd.) on the surface of which an antireflection layer composed of a multilayered inorganic dielectric thin film was formed was used as a light control plate via an adhesive. The iodine-based polarizing film (“Sumikaran SK-1842” was attached so that the scattering direction of the light control plate and the absorption axis of the polarizing film were parallel to each other via the adhesive.
AP7 ", manufactured by Sumitomo Chemical Co., Ltd., and the retardation of the retardation film is 25 degrees with respect to the absorption axis of the polarizing film through the adhesive of the polarizing film. An optical film (structure: antireflection layer / acrylic sheet / light control plate [0 °] / polarizing film / retardation film [25 °]) was obtained by sticking to the film.

This optical film was placed on the SM-FTN-LCD on the front side (front side) of a word processor (trade name "OASYS 30LX-401", manufactured by Fujitsu Limited) via an acrylic adhesive. I placed it. The absorption axis direction of the polarizing film, the scattering direction of the light control plate and the slow axis direction of the retardation film at this time are as shown in FIG.
-An angle 16 formed by the absorption axis direction 13 of the polarizing film when viewed from the upper (front) side of the panel with reference to the long side 20 of the LCD.
Is set to 90 degrees. The angle formed by the scattering direction 11 of the light control plate with respect to the long side 20 of the SM-FTN-LCD is 90 degrees, and the angle formed by the slow axis direction 12 of the retardation film is 1
5 becomes 115 degrees. On the lower (back) side of the SM-FTN-LCD, an acrylic adhesive is used, and SM-FT
The polarizing film was arranged so that the absorption axis direction of the polarizing film was 0 ° and the slow axis direction of the retardation film was 115 ° when viewed from the lower (back) side of the panel with reference to the long side of the N-LCD. When the liquid crystal display device thus obtained was visually observed, it had good viewing angle characteristics not only in the horizontal direction but also in the upward direction.

Example 2 The photopolymerizable composition used in Example 1 was applied to a polyethylene terephthalate film having a thickness of 188 μm, and ultraviolet rays were irradiated at an irradiation angle of 25 ° by the apparatus shown in FIGS. 1 and 2 to control the light. A plate was made. The thickness of this light control plate is 162
The maximum haze value was 82%, and the scattering angle range defined by a haze value of 30% or more was 4 to 47 degrees. The photopolymerizable composition used in Example 1 was further applied onto the above-mentioned light control plate prepared on a polyethylene terephthalate film, and ultraviolet rays were applied at an irradiation angle of -35 degrees by the apparatus shown in FIGS. 1 and 2. After the irradiation, it was peeled from the polyethylene terephthalate film to prepare a two-layer light control plate. The thickness of the two-layer light control plate is 32
6 μm, domain spacing 3 μm, maximum haze value of 82
%, And the scattering angle range defined by a haze value of 30% or more was −13 degrees to −47 degrees and 4 degrees to 47 degrees.

The polycarbonate film formed by the solvent casting method is uniaxially stretched by the tenter stretching method according to the method of Japanese Patent Application No. 6-31669 (= JP-A-7-23007) (thickness = 60 μm, retardation = 240 nm, α = 1.06), and then a biaxially stretched polycarbonate film is bonded to one side using an acrylic adhesive, and the bonded product is heat relaxed at 165 ° C. (stretching of a uniaxially stretched film by heat relaxation). 2% in the axial direction and 4% in the direction orthogonal to the stretching axis were contracted), and then the biaxially stretched polycarbonate film was peeled and removed to obtain a retardation film A having a small angle dependence of retardation (thickness: 62 μm). , Retardation = 540 nm, α =
1.06). A cellulose acetate film formed by the solvent casting method was stretched by a longitudinal uniaxial stretching method to obtain a retardation film B (thickness 126 μm, retardation = 225 nm, α = 1.00). The retardation film A and the retardation film B were laminated using an acrylic pressure-sensitive adhesive so that their slow axes were orthogonal to each other to obtain a retardation film having retardation = 315 nm and α = 1.10. .

An iodine-based polarizing film (“SP-1852AP7-AG1”, manufactured by Sumitomo Chemical Co., Ltd.) having an anti-glare layer formed on the surface thereof was used, and the scattering direction of the light control plate was adjusted to the absorption axis of the polarizing film via an adhesive. It is attached to a light control plate composed of two layers so that the directions are 0 ° and 180 ° with respect to each other, and the slow axis of the retardation film is 25 degrees with respect to the absorption axis of the polarizing film via an adhesive. To obtain an optical film (structure: anti-glare layer / polarizing film / light control plate [0 °] / light control plate [180 °] / retardation film [25 °]). It was This optical film is
It has the functions of a light control plate, a retardation film, and a polarizing film, and is effective in improving the viewing angle characteristics of a liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a side view showing an example of an ultraviolet irradiation device used for manufacturing a light control plate.

FIG. 2 is a perspective view showing an example of an ultraviolet irradiation device used for producing a light control plate.

FIG. 3 is a diagram showing a relationship between a scattering direction of a light control plate and a slow axis direction of a retardation film with respect to an absorption axis of a polarizing film.

FIG. 4 is a diagram showing a relationship between an absorption axis direction of a polarizing film, a scattering direction of a light control plate, and a slow axis direction of a retardation film for the SM-FTN-LCD of Example 1.

[Explanation of symbols]

1 bar-shaped ultraviolet lamp, 2 light-shielding plate, 3 conveyor, 4 polyethylene terephthalate film coated with composition for light control plate, 5 irradiation angle, 11 light scattering direction of light control plate, 12 in-plane slow axis of retardation film Direction, 13 absorption axis direction of polarizing film, 14 angle of in-plane slow axis of retardation film with respect to absorption axis of polarizing film, 15 in-plane slow axis of retardation film with respect to long side of SM-FTN-LCD Angle, the angle of the absorption axis of the polarizing film with respect to the long side of 16 SM-FTN-LCD, and the long side of 20 SM-FTN-LCD.

Front page continuation (72) Inventor Shinichi Takemura 2-10-1 Tsukahara, Takatsuki, Osaka Sumitomo Chemical Co., Ltd. (56) Reference JP-A-7-64069 (JP, A) JP-A-3-233404 (JP, A) JP-A-3-13916 (JP, A) JP-A-6-250020 (JP, A) JP-A-6-174923 (JP, A) Patent 3134710 (JP, B2) (58) Field (Int.Cl. ⁷ , DB name) G02B 5/00-5/136 G02B 5/30 G02F 1/1335 G02F 1/13363

Claims (8)

(57) [Claims] 1. A method comprising: (a) forming a film containing a composition containing two or more kinds of photopolymerizable monomers and / or oligomers having mutually different refractive indexes, and then irradiating the composition with ultraviolet light ;
At least one refractive index modulation type light control plate having a domain interval of 1 μm to 20 μm , (b) a polycarbonate resin, a polysulfone resin,
Polyarylate resin, polyether sulfone resin,
A retardation film made of a thermoplastic resin having a positive refractive index anisotropy selected from polyester resins, polyvinyl alcohol resins and cellulose resins (however, (in-plane retardation value) / (thickness direction) The optical film is formed by laminating (c) a polarizing film. 2. The optical film according to claim 1, wherein the difference in the refractive index of at least two kinds of the photopolymerizable monomer and / or oligomer is 0.01 or more. 3. The optical film according to claim 1, wherein the composition for the light control plate contains a compound having a refractive index different from that of the photopolymerizable monomer or oligomer and having no photopolymerizability. 4. The light control plate has a haze value of 30% or more and a light scattering ability.
And the light scattering angle below 30%.
The optical film according to claim 1, which is a light control plate having a light ray incident angle range not shown . 5. The maximum cloudiness in the ray incident angle range showing the ray scattering ability.
The optical film according to claim 4, having a value of 30% to 85% . 6. The retardation film has a wavelength of 589 nm.
At a wavelength of 486 nm with respect to the retardation value R (589)
Ratio of retardation value R (486)
/ R (589)] is 1.07 or more, the positive refractive index anisotropy
The optical film according to claim 1 , wherein the optical film comprises a thermoplastic resin having the same . 7. At least two glass substrates having electrodes
One side is transparent, and there is a positive gap between the two glass substrates.
Has a dielectric anisotropy and twist angle of 60 to 120 degrees
In a liquid crystal cell in which a certain nematic liquid crystal layer is arranged,
The optical filter according to claim 1, which is provided above and / or below the crystal cell.
A liquid crystal display device with a rum . 8. At least one of two glass substrates having an electrode is transparent, has positive dielectric anisotropy between the two glass substrates, and has a twist angle of 180 ° to 270 ° <. In a liquid crystal cell in which a nematic liquid crystal layer is arranged,
A liquid crystal display device comprising the optical film according to claim 1 disposed above and / or below a liquid crystal cell.