JP2001100043A - Polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of display quality due to the reflection of external light and to expand the visual field angle of a TN mode liquid crystal display device and a color liquid crystal display device. SOLUTION: This polarizing plate having two transparent substrates interposing a polarizing layer comprises an optical compensation layer including an optically anisotropic layer on the surface opposite to the polarizing layer of one substrate of the two transparent substrates and a reflection preventing layer on the surface opposite to the polarizing layer of the other transparent substrate. The optically anisotropic layer consists of a compound having a discotic structure unit and has negative double refractivity and the disk face of the discotic structure unit is inclined with respect to the surface of the transparent substrate and the angle formed by the disk face of the discotic structure unit and the surface of the transparent substrate is changed in the direction of the depth of the optically anisotropic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate having an optical compensation function and an antireflection function, a liquid crystal display device using the same, and a color liquid crystal display device.

[0002]

2. Description of the Related Art FIG. 1 shows the configuration of a conventional liquid crystal display device. In a general liquid crystal display device, an edge-light type backlight 11 is disposed on the rearmost surface, a light guide plate 12 for emitting light of the backlight to the surface in order from the rear surface, and a scattering sheet for equalizing the brightness of the light. 13, further arranged as one or a plurality of light control sheets 14 having a function of condensing the light uniformized by the scattering sheet in a predetermined direction, or a function of selectively transmitting and reflecting specific polarized light, The light that has passed through these films becomes a pair of polarizing plates 1
The light enters a liquid crystal cell 17 sandwiched between 5 and 16. 1
8 is a cold cathode fluorescent tube of a light source, and 19 is a reflection sheet.

[0003] The antireflection layer is generally made of CRT, PDP, L
In an image display device such as a CD, in order to prevent a decrease in contrast or reflection of an image due to reflection of external light, the image display device is disposed on the outermost surface of a display that reduces the reflectance using the principle of optical interference. That is, the antireflection layer is provided on the 16 display side in FIG.

[0004]

However, in an antireflection layer having only a hard coat layer and a low refractive index layer on a transparent support, the low refractive index layer must have a sufficiently low refractive index to reduce the reflectance. In order to reduce the average reflectance at 450 nm to 650 nm to 1.6% or less in an antireflection film using triacetyl cellulose as a support and a UV-cured coating of dipentaerythritol hexaacrylate as a hard coat layer. Has a refractive index of 1.
Must be 40 or less. Materials having a refractive index of 1.40 or less include magnesium fluoride and calcium fluoride for inorganic substances, and fluorine-containing compounds having a large fluorine content for organic substances. These fluorine compounds have no cohesive force and are arranged on the outermost surface of the display. The resulting film had insufficient scratch resistance. Therefore, in order to have sufficient scratch resistance, a compound having a refractive index of 1.43 or more was required.

Japanese Patent Application Laid-Open No. 7-287102 describes that the reflectance is reduced by increasing the refractive index of the hard coat layer. However, such a high-refractive-index hard coat layer has a large difference in refractive index from the support, so that color unevenness of the film occurs, and the wavelength dependence of the reflectivity also has a large amplitude. One of the objects of the present invention is to form a hard coat layer and a low refractive index layer on a support, and to provide a simple and inexpensive and sufficient antireflection performance, scratch resistance, and stain resistance. Another object of the present invention is to provide an antiglare antireflection film having less color unevenness.

[0006] Incidentally, the display method of the LCD can be largely divided into a birefringence mode and an optical rotation mode. A super twisted nematic liquid crystal display device (hereinafter, STN-LCD) using a birefringence mode has 9
A super twisted nematic liquid crystal having a twist angle exceeding 0 degrees and steep electro-optical characteristics is used.
Therefore, the STN-LCD can display a large amount of data by time-division driving. However, since the STN-LCD has problems such as a slow response speed (several hundred milliseconds) and difficulty in gradation display, a liquid crystal display device using an active element (eg, T
FT-LCD and MIM-LCD). In TFT-LCD and MIM-LCD, a twisted nematic liquid crystal having a twist angle of 90 degrees and positive birefringence is used to display an image. These are the display modes of the TN-LCD which are the optical rotation modes, and have a high speed response (several tens of milliseconds) and a high contrast, and thus are advantageous in many points as compared with the birefringence mode. However, the TN-LCD has a problem that the display color and display contrast change depending on the angle at which the liquid crystal display device is viewed (viewing angle characteristics), so that the TN-LCD is harder to see than the CRT.

In order to improve the viewing angle characteristics, Japanese Patent Application Laid-Open Nos. Hei 4-229828 and Hei 4-258923 propose to provide a retardation plate (optical compensation sheet) between a pair of polarizing plates and a liquid crystal cell. Has been described. The retardation plate proposed in the above publication has no optical action from directly in front of the liquid crystal cell because the retardation in the vertical direction is almost zero, but the retardation appears when tilted. . This compensates for the phase difference that occurs in the oblique direction of the liquid crystal cell. As such an optical compensation sheet, a sheet having negative birefringence so as to compensate for positive birefringence of the nematic liquid crystal and having an inclined optical axis is effective.

[0008] JP-A-6-75115 and EP0576
304A1 describes an optical compensatory sheet having negative birefringence and an inclined optical axis. This sheet is produced by stretching a polymer such as polycarbonate or polyester, and has a main refractive index direction inclined from the normal line of the sheet. Since such a sheet requires an extremely complicated stretching treatment, it is very difficult to stably produce a large-area and uniform optical compensation sheet by this method.

On the other hand, a method using a liquid crystal polymer is also described in JP-A-3-9326 and JP-A-3-291601. This is an optical compensation sheet obtained by applying a polymer having liquid crystallinity to the surface of the alignment layer on the support. However, a polymer having liquid crystallinity does not show sufficient alignment on the alignment layer, and thus cannot increase the viewing angle in all directions. JP-A-5-215921 describes an optical compensation sheet (birefringent plate) comprising a support and a polymerizable rod-like compound having liquid crystallinity and positive birefringence. This optical compensation sheet is obtained by applying a solution of the polymerizable rod-like compound to a support and curing by heating. However, since the polymer having the liquid crystal property does not have birefringence, the viewing angle in all directions cannot be increased.

Japanese Patent Application Laid-Open No. Hei 8-50206 has a layer having a negative birefringence made of a compound having a discotic structural unit, and the angle between the discotic compound and the support in the depth direction of the layer. An optical compensatory sheet characterized by a change is described. According to this method, the viewing angle as viewed from the contrast greatly increases in all directions, and almost no image quality deterioration such as yellowing when viewed from an oblique direction is observed. However,
Since the deterioration of the display quality due to the reflection of external light cannot be improved only by the optical compensation sheet, further improvement is required.

As described above, an object of the present invention is to prevent display quality deterioration due to reflection of external light and to improve the viewing angle of a TN mode liquid crystal display device and a color liquid crystal display device in all directions by improving the viewing angle. It is an object of the present invention to provide a liquid crystal display device having a high display quality, and to supply them at a low cost by stably manufacturing them by a simple method.

[0012]

The object of the present invention has been attained as follows. (1) In a polarizing plate having a polarizing layer sandwiched between two transparent supports, optical compensation comprising an optically anisotropic layer on a surface of one of the transparent supports opposite to the polarizing layer. A polarizing plate having an antireflection layer on the surface of the other transparent support opposite to the polarizing layer, wherein the optically anisotropic layer comprises a compound having a discotic structural unit. A birefringent layer, wherein the disc surface of the discotic structural unit is inclined with respect to the transparent support surface, and the angle formed between the disc surface of the discotic structural unit and the transparent support surface is an optically anisotropic layer. Characterized in that it changes in the depth direction of the polarizing plate. (2) The polarizing plate according to claim 1, wherein the angle increases as the distance of the optically anisotropic layer from the support surface side increases. (3) The polarizing plate according to (1), wherein the optically anisotropic layer further contains a cellulose ester. (4) The transparent support on the optically anisotropic layer side has an optically negative uniaxial property, has an optical axis in the normal direction of the transparent support surface, and further satisfies the following conditions ( The polarizing plate according to 1).

## EQU2 ## 20 ≦ {(nx + ny) / 2−nz} × d ≦
400 (d: thickness of optical compensation layer) (5) The polarizing plate according to (1), wherein an alignment layer is formed between the optically anisotropic layer and the transparent support. (6) The polarizing plate according to (5), wherein the alignment layer comprises a cured film of a polymer. (7) The polarizing plate according to (1), wherein the optically anisotropic layer is a monodomain or has a large number of domains having a size of 0.1 μm or less. (8) The anti-reflection layer is an anti-glare anti-reflection layer including a base material and at least one low-refractive-index layer composed of a fluorine-containing compound having a refractive index of at least one layer of 1.38 to 1.49. The polarizing plate according to (1), further comprising an antiglare layer composed of particles and a binder having a refractive index of 1.57 to 2.00 between the material and the low refractive index layer. (9) The low refractive index layer has a dynamic friction coefficient of 0.03 to 0.0.
15. The polarizing plate according to (8), comprising a fluorine-containing compound which is crosslinked by heat or ionizing radiation having a contact angle of 90 to 120 ° with water. (10) The polarizing plate according to (8), wherein in the antiglare layer, a difference in refractive index between the particles and the binder is less than 0.05. (11) The polarizing plate according to (11), wherein the particles have an average particle size of 1 to 10 μm. (12) The binder of the antiglare layer is a heat or ionizing radiation cured product of a mixture of a high refractive index monomer having a refractive index of 1.57 to 2.00 and a monomer having two or more ethylenically unsaturated groups. The polarizing plate according to (8), which is characterized in that: (13) The binder of the anti-glare layer is Al, Zr, Zn, T
The polarized light according to (8), which is a heat or ionizing radiation cured product of a mixture of ultrafine particles of a metal selected from i, In, and Sn and a monomer having two or more ethylenically unsaturated groups. Board. (14) The anti-glare layer has an average particle size of 0.01 to 1.0 μm.
m, the refractive index is 1.35 to 1.65 or 2.00 to 3.00, and the difference from the refractive index of the binder is 0.03.
The polarizing plate according to (8), comprising the scattering particles described above. (15) The polarizing plate according to (1) to (14) is used as a display-side polarizing plate among two polarizing plates disposed on both sides of the liquid crystal cell, and an optically anisotropic layer is formed on the liquid crystal cell side. A liquid crystal display device, wherein the liquid crystal display device is arranged to face. (16) A liquid crystal cell including a pair of substrates having a transparent electrode, a pixel electrode, and a color filter, and a twist-aligned nematic liquid crystal sealed between the substrates, and a pair of optical compensation sheets provided on both sides of the liquid crystal cell. In a color liquid crystal display device comprising a pair of polarizing plates disposed outside thereof, the polarizing plate described in (1) to (14) is used as a display-side optical compensation sheet and a polarizing plate of a liquid crystal cell, and the optical anisotropic material is used. The liquid crystal cell side, further comprising an optically anisotropic layer having a negative birefringence comprising a compound having a discotic structural unit on the backlight side of the liquid crystal cell, wherein the discotic structural unit circle The disc surface is inclined with respect to the transparent support surface, and the angle between the disc surface of the discotic structure unit and the transparent support surface changes in the depth direction of the optically anisotropic layer. Liquid crystal display device having an optical compensation sheet.

Further, the optically anisotropic layer preferably satisfies the following conditions. (1) An optically anisotropic layer in which the angle between the disc surface of the discotic structural unit and the transparent support surface increases with an increase in the distance from the support surface side, and the angle changes in the range of 5 to 85 degrees. . (2) The minimum value of the angle is in the range of 0 to 85 degrees (more preferably, 5 to 40 degrees), and the maximum value is 5 to 9 degrees.
An optically anisotropic layer in the range of 0 degrees (more preferably 30 to 85 degrees). (3) An optically anisotropic layer containing a cellulose ester (more preferably, cellulose acetate butyrate). (4) An optically anisotropic layer having a non-zero minimum retardation absolute value in a direction inclined from the normal direction of the polarizing plate. (5) The substrate of the liquid crystal cell has an alignment surface that has been rubbed in one direction, and the direction when the direction of the minimum value of the retardation of the optically anisotropic layer is orthogonally projected onto the liquid crystal cell and the optically anisotropic layer. An optically anisotropic layer disposed so that an angle between the rubbing direction of a liquid crystal cell substrate adjacent to the substrate and the rubbing direction is 90 to 270 degrees.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of a liquid crystal display device using the polarizing plate of the present invention having an optical compensation function and an antireflection function will be described with reference to the drawings.

FIG. 2 is an example of a schematic sectional view showing the layer structure of the optical compensation layer. The optical compensation layer has a layer configuration in the order of the transparent support 21, the alignment layer 22, and the optically anisotropic layer 23. The optically anisotropic layer is composed of the liquid crystal discotic compounds 24a and 24.
b, 24c, the optical axis thereof and the normal direction 2 of the transparent support.
5, respectively, form inclination angles of θa, θb, and θc.
This inclination angle increases from the transparent support side of the optically anisotropic layer toward the surface side.

FIG. 3 shows the optical characteristics of the optical compensation layer. The alignment layer is subjected to a treatment such as rubbing for aligning the liquid crystalline discotic compound. Numeral 31 indicates a rubbing direction of the alignment layer. n1, n2 and n3 represent orthogonal triaxial refractive indexes of the optical compensation layer, and when viewed from the front, n1 ≦ n3
Satisfies the relationship of ≦ n2. The optical compensation layer has a non-zero retardation absolute minimum value in a direction inclined from the normal direction of the transparent support. In the figure, reference numeral 32 denotes the direction showing the minimum value of the absolute value of the retardation and the normal direction 2 of the transparent support.
This is the angle made with 5. In order to improve the viewing angle characteristics of the TN-LCD, 32 is preferably from 5 to 50 degrees, and particularly preferably from 10 to 40 degrees.

The optical compensation layer satisfies the following expression.

[Equation 3] 20 ≦ {(nx + ny) / 2−nz} × d ≦
400 (d: thickness of optical compensation layer)

The optical compensation layer preferably satisfies the following expression.

[Equation 4] 50 ≦ {(nx + ny) / 2−nz} × d ≦
400

It is particularly preferable that the optical compensation layer satisfies the following expression.

[Equation 5] 100 ≦ {(nx + ny) / 2−nz} × d
≦ 400

The transparent support used for the optical compensation layer includes:
It is preferable to use a plastic film. Examples of plastic film materials include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose),
Polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene-1,2-diphenoxyethane-
4,4′-dicarboxylate, polybutylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polypropylene, polyethylene, polymethylpentene), polysulfone, polyethersulfone, polyarylate, polyetherimide, Polymethyl methacrylate and polyether ketone, commercially available products of ZEONEX (ZEON CORPORATION)
And ARTON (manufactured by JSR Corporation).

The light transmittance of the transparent support is preferably at least 80%, more preferably at least 86%. The transparent support preferably has optical isotropy when viewed from the front. The haze of the transparent support is 2.0%
Or less, more preferably 1.0% or less. The refractive index of the transparent support is 1.4 to 1.
7 is preferred. From these viewpoints, triacetyl cellulose, polycarbonate and polyethylene terephthalate, ZEONEX, and ARTON are preferable.
Triacetyl cellulose is particularly preferred as the protective film for protecting the polarizing layer of the polarizing plate for CD.

The main refractive indices in the plane of the transparent support are nx, ny,
When the main refractive index in the thickness direction is nz and the thickness is db, the relation of the main refractive index satisfies nz <ny = nx (negative uniaxiality) and is expressed by {(nx + ny) / 2-nz} × d. The retardation is from 20 to 400 nm. The retardation of the transparent support is more preferably from 30 to 150 nm. Also, nx and ny do not need to be exactly equal, and there is no practical problem if | nx-ny | / | nx-nz | ≦ 0.2. The front retardation represented by | nx−ny | × db is preferably 50 nm or less, more preferably 20 nm or less.

An undercoat layer may be provided on the transparent support in order to impart adhesion to an adjacent layer. The material for forming such an undercoat layer is not particularly limited. For example, on triacetyl cellulose, gelatin or poly (meth) acrylate resin and its substituted product, styrene-
Butadiene resin or the like is used. Further, a surface treatment such as a chemical treatment, a mechanical treatment, a corona treatment, and a glow discharge treatment may be performed.

The alignment layer functions to define the alignment direction of the liquid crystalline discotic compound provided thereon. And this orientation gives an optical axis inclined from the normal direction of the transparent support. The orientation layer is not particularly limited as long as it can impart orientation to the optically anisotropic layer. Preferred examples of the alignment layer include:
A layer formed by rubbing the surface formed by an organic compound, an obliquely deposited layer of an inorganic compound, a microgroove layer formed by patterning with a resist, or ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate, etc. Langmuir
Blodgett films, and dielectric layers oriented by electric or magnetic fields can be mentioned. The rubbing treatment layer is preferable because it is simple and inexpensive in production.

Examples of the organic compound for the alignment layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), and styrene / vinyltoluene copolymer. Copolymers, polymers such as chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethylcellulose, polyethylene, polypropylene, polycarbonate, etc. And a compound such as a silane coupling agent. Among them, polyimide, polystyrene, polyvinyl alcohol and an alkyl-modified polyvinyl alcohol containing an alkyl group (preferably having 6 or more carbon atoms) are preferable, and an alkyl-modified polyvinyl alcohol containing an alkyl group (preferably having 6 or more carbon atoms) is particularly preferable. As the polyimide, polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd.,
Nissan Chemical Co., Ltd. SE series, etc.) and baked at 100 to 300 ° C. for 0.5 to 1 hour.
03, MP203, R1130 (Kuraray Co., Ltd.
Manufactured).

The rubbing treatment can use a treatment method widely used as a liquid crystal alignment treatment step for LCD. That is, a method of obtaining the orientation by rubbing the surface of the orientation layer in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, rubbing is performed several times using a cloth on which fibers having a uniform length and thickness are planted on average.

The optically anisotropic layer may be oriented without using an orientation layer. This includes a method in which the liquid crystalline discotic compound layer forming the optically anisotropic layer is oriented by an electric field, a magnetic field, polarized light irradiation, oblique non-polarized light irradiation, or the like.

The optically anisotropic layer is a layer having a negative birefringence made of a compound having a discotic structural unit. The optically anisotropic layer is a layer of a liquid crystalline discotic compound or a polymer layer obtained by curing a polymerizable discotic compound. Examples of the discotic compound of the present invention include C.I. Destrade et al., Mol.
Cryst. 71, p. 111 (1981), benzene derivatives, Mol. Cryst. 122
Vol. 141, 1985, Physics. Let
t, A, vol. 78, p. 82 (1990); A report by Kohne et al., A
ngew. Chem. Soc. 96, 70 (198
4 years) and the cyclohexane derivative described in J. M.
J. Lehn et al. Chem. Commun.
1794 (1985); Research report by Zhang et al. Am. Chem. Soc. 116, 2655
And azacrown-based and phenylacetylene-based macrocycles described on page (1994). The above discotic (disk-shaped) compounds generally have a structure in which these are used as a core of a molecular center, and linear alkyl groups, alkoxy groups, substituted benzoyloxy groups, and the like are radially substituted as side chains thereof. And what is generally called a discotic liquid crystal is included. However, the present invention is not limited to the above description as long as the molecule itself has negative uniaxiality and can impart a certain orientation.
In the present invention, "formed from a discotic compound" does not necessarily mean that the final product is the compound described above. For example, a low-molecular discotic liquid crystal has a functional group that is crosslinked by heat, ionizing radiation, or the like. And those having lost liquid crystallinity due to high molecular weight by irradiation with heat or ionizing radiation.

Preferred examples of the discotic compound are shown below.

[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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For the optically anisotropic layer, a coating solution prepared by dissolving a discotic compound and other compounds is applied on the orientation layer, dried, and then heated to a discotic nematic phase formation temperature, and the orientation state is maintained. Obtained by cooling. Alternatively, after heating to a discotic nematic phase formation temperature, the polymer may be polymerized and fixed by irradiation with ionizing radiation. The transition temperature between the discotic nematic liquid crystal phase and the solid phase is preferably from 50 to 300 ° C, particularly preferably from 70 to 170 ° C.

The optically anisotropic layer contains a plasticizer, a surfactant, a polymerizable monomer, a polymerizable monomer, etc. in order to control the tilt angle of the liquid crystalline discotic compound, the temperature at which the discotic nematic phase is formed, the compatibility, and the coating properties. Molecular compounds, etc.
Any compound may be added as long as it does not inhibit the orientation of the discotic compound.

The polymerizable monomer preferably has a vinyl group, a vinyloxy group, an acryloyl group and a methacryloyl group. The polymerizable monomer can be used in an amount of 1 to 50% by weight, preferably 5 to 30% by weight, based on the discotic compound.

As the polymer compound, any compound can be used as long as it has compatibility with the discotic compound. As the polymer compound, a cellulose ester is preferable, and among them, cellulose acetate butyrate is particularly preferable. The polymer compound can be used in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the discotic compound. Further, the degree of butyrylation of cellulose acetate butyrate is preferably 30 to 80%, and the degree of acetylation is preferably 30 to 80%.

FIG. 4 is an example of a schematic sectional view showing the layer structure of the antireflection layer. The antireflection layer has a layer structure in the order of the transparent support 41, the antiglare layer 42, and the low refractive index layer 43. The anti-glare layer contains particles 44 for imparting anti-glare properties, and the particles provide the anti-glare properties by forming irregularities on the surface. For the low refractive index layer, a fluorine-containing compound which is crosslinked by heat or ionizing radiation is used, and its refractive index and film thickness preferably satisfy the following formula.

[0046]

[Equation 6] mλ / 4 × 0.7 <n ₁ d ₁ <mλ / 4 × 1.3

Where n is a positive odd number (generally 1),
n1 is the refractive index of the low refractive index layer, and d1 is the thickness (nm) of the low refractive index layer.

As the transparent support used for the antireflection layer,
It is preferable to use a plastic film. Examples of plastic film materials include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose),
Polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene-1,2-diphenoxyethane-
4,4′-dicarboxylate, polybutylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polypropylene, polyethylene, polymethylpentene), polysulfone, polyethersulfone, polyarylate, polyetherimide, Polymethyl methacrylate and polyether ketone, commercially available products of ZEONEX (ZEON CORPORATION)
And ARTON (manufactured by JSR Corporation).

The light transmittance of the transparent support is preferably at least 80%, more preferably at least 86%. The transparent support preferably has optical isotropy when viewed from the front. The haze of the transparent support is 2.0%
Or less, more preferably 1.0% or less. The refractive index of the transparent support is 1.4 to 1.
7 is preferred. From these viewpoints, triacetyl cellulose, polycarbonate and polyethylene terephthalate, ZEONEX, and ARTON are preferable.
Triacetyl cellulose is particularly preferred as the protective film for protecting the polarizing layer of the polarizing plate for CD.

An undercoat layer may be provided on the transparent support in order to impart adhesion to an adjacent layer. The material for forming such an undercoat layer is not particularly limited. For example, on triacetyl cellulose, gelatin or poly (meth) acrylate resin and its substituted product, styrene-
Butadiene resin or the like is used. Further, a surface treatment such as a chemical treatment, a mechanical treatment, a corona treatment, and a glow discharge treatment may be performed.

The binder used for the antiglare layer has a refractive index of 1.5.
There is no particular limitation as long as it is 7 to 2.00. It is preferable to have a hard coat property in order to make it difficult to damage itself during processing.

In order to impart a hard coat property to the antiglare layer, a polymer having a saturated hydrocarbon or polyether as a main chain is preferable, and a polymer having a saturated hydrocarbon as a main chain is more preferable. . The binder polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as a main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups.

Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate) Pentaerythritol tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethanetri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta ( (Meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and the like Conductors (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, methylenebisacrylamide), and methacryl Amides are included. The polymer having a polyether as a main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. These monomers having an ethylenically unsaturated group need to be cured by a polymerization reaction by ionizing radiation or heat after coating.

Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder polymer by a reaction of a crosslinkable group.
Examples of the crosslinkable functional group include an isocyanate group, an epoxy group, an aziridine group, an oxazoline group, an aldehyde group, a carbonyl group, a hydrazine group, a carboxyl group, a methylol group, and an active methylene group. Vinyl sulfonic acid, acid anhydride, cyanoacrylate derivative, melamine,
Metal alkoxides such as etherified methylols, esters and urethanes, and tetramethoxysilane can also be used as monomers for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of a decomposition reaction, such as a block isocyanate group, may be used. Further, in the present invention, the cross-linking group is not limited to the above-mentioned compound, but may be one which shows reactivity as a result of decomposition of the above-mentioned functional group. These compounds having a cross-linking group need to be cross-linked by heat or the like after coating.

In order to increase the refractive index of the binder of the antiglare layer, a monomer having a high refractive index of 1.57 or more, preferably 1.65 or more can be used. Examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinylnaphthalene, vinylphenylsulfide, 4-methacryloxyphenyl-4′-methoxyphenylthioether and the like. The polymer having a polyether as a main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. These monomers having an ethylenically unsaturated group need to be cured by a polymerization reaction by ionizing radiation or heat after coating.

In order to increase the refractive index of the binder of the antiglare layer, titanium, aluminum, indium, zinc, tin,
It is preferable to contain fine particles of at least one oxide selected from antimony having a particle size of 100 nm or less, preferably 50 nm or less. Examples of the fine particles include TiO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ ,
Sb ₂ O ₃ , ITO and the like can be mentioned. The addition amount of the inorganic fine particles is preferably from 10 to 90% by weight, more preferably from 20 to 80% by weight, and particularly preferably from 30 to 60% by weight based on the total weight of the hard coat layer.

In the antiglare layer, scattering particles may be used for the purpose of imparting antiglare properties, preventing deterioration in reflectance due to interference of the hard coat layer, and preventing color unevenness. The scattering particles have an average particle size of 0.0
1 to 1.0 μm, the refractive index is 1.35 to 1.65 or 2.00 to 3.00, and the difference from the refractive index of the binder is 0.03 or more. By adding these scattering particles, internal scattering occurs in the antiglare layer, and the entire antiglare layer becomes a non-uniform refractive index layer whose refractive index is not defined by one value.

In order to impart the antiglare property to the antiglare layer, for example, a transparent support described in Japanese Patent Application Laid-Open No. S61-209154, which is coated with an uneven layer obtained by adding particles to a binder, or disclosed in No. 6-16851, in which a film on which an uneven surface is formed in advance is bonded to a coating layer on a transparent support to transfer the unevenness, or another layer such as a hard coat layer is directly applied to the transparent support. And those in which irregularities are formed by embossing. Above all, the method of forming particles by adding particles to the binder,
This is preferable because it can be easily and stably manufactured.

The particles imparting anti-glare properties are not particularly limited as long as irregularities are formed on the surface of the anti-glare layer. However, in order to control internal scattering, the difference in refractive index between the particles and the binder is less than 0.05. And more preferably less than 0.02. In order to effectively form irregularities on the surface of the antiglare layer, the average particle size is preferably 1 to 10 μm, more preferably 1.5 to 6 μm. Examples of particles include polymethyl methacrylate resin, fluorine resin, vinylidene fluoride resin, silicone resin, epoxy resin, nylon resin, polystyrene resin, phenol resin, polyurethane resin, crosslinked acrylic resin, crosslinked polystyrene resin, melamine resin, benzoguanamine resin, etc. Is mentioned. The particles are preferably insoluble in water and organic solvents. The particles to be added to the anti-glare layer may be used in combination of two or more kinds of particles for controlling unevenness.

As the compound used for the low refractive index layer, a fluorine-containing compound having a refractive index of 1.38 to 1.49 is preferable, and a dynamic friction coefficient of 0.03 to 0.15, More preferred are fluorine-containing compounds which are crosslinked by heat or ionizing radiation having a contact angle of 90 to 120 ° with respect to. It may be used in combination with other compounds in order to adjust coatability, film hardness and the like. As the crosslinkable fluorine-containing compound,
Examples thereof include a fluorinated monomer and a crosslinkable fluorinated polymer, and a crosslinkable fluorinated polymer is preferable from the viewpoint of applicability.

Examples of the crosslinkable fluoropolymer include a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane) and the like, and a fluorine-containing monomer and a crosslinkable group. A fluorinated copolymer having a monomer for application as a constitutional unit is exemplified. Specific examples of the fluorine-containing monomer unit,
For example, a portion of fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), (meth) acrylic acid or Perfluorinated alkyl ester derivatives (for example, Biscoat 6F
M (manufactured by Osaka Organic Chemicals) and M-2020 (manufactured by Daikin)
Etc.), fully or partially fluorinated vinyl ethers, etc. As a monomer for providing a crosslinkable group, in addition to a (meth) acrylate monomer having a crosslinkable functional group in the molecule in advance such as glycidyl methacrylate, a monomer having a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc. ) Acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.). It is known from JP-A-10-25388 and JP-A-10-147739 that the latter can introduce a crosslinked structure after copolymerization.

In addition to the polymer having the above-mentioned fluorine-containing monomer as a constitutional unit, a copolymer with a monomer containing no fluorine atom may be used. There is no particular limitation on the monomer units that can be used in combination. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylates (methyl acrylate,
Methyl acrylate, ethyl acrylate, acrylic acid 2-
Ethylhexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyltoluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether) And the like, vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, acrylonitrile derivatives and the like. .

Each of the optical compensation layer and the antireflection layer is formed by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method or an extrusion coating method (US Pat.
681294) can be formed by coating. Two or more layers may be applied simultaneously. For the method of simultaneous coating, see U.S. Pat. Nos. 2,761,791; 2,918,898; 3,508,947;
No.28 and Yuji Harazaki, Coating Engineering,
253 pages, Asakura Shoten (1973).

FIG. 5 shows an example of a configuration diagram of a polarizing plate having an optical compensation function and an antireflection function according to the present invention. In the polarizing plate of the present invention, a polarizing layer 51 is sandwiched between two transparent supports 21 and 41, and an optically anisotropic layer 23 is provided on a surface of one of the transparent supports opposite to the polarizing layer. And an antireflection layer 53 on the surface of the other transparent support opposite to the polarizing layer.

The polarizing plate having an optical compensation function and an antireflection function of the present invention is applied to a liquid crystal display device. FIG. 6 shows an example of a configuration diagram of a liquid crystal display device. The anti-reflection layer 61 is disposed as a display-side polarizing plate with the anti-reflection layer facing the display side, and the optical compensation layer 62b is bonded to the liquid crystal cell 63 via an adhesive 65 or the like. The polarizing plate having this optical compensation layer is also used as the backlight side polarizing plate, and the optical compensation layer 62a is bonded to the liquid crystal cell via an adhesive or the like.

FIG. 7 shows a typical layout of the polarizing plate of the present invention for performing optical compensation. Although the backlight 74 side is the lower side, the rubbing direction of the lower optical compensation layer 62a is 71
a, the rubbing direction of the upper optical compensation layer 62b is 71b. The dashed arrow 72a of the liquid crystal cell 63 indicates the rubbing direction of the backlight-side liquid crystal cell substrate, the solid line 72b indicates the rubbing direction of the display-side liquid crystal cell substrate, and 73a and 73b indicate the transmission axes of the polarizing plates, respectively.

As an arrangement diagram other than that shown in FIG. 7, the optical compensation layer may not be divided into two upper and lower polarizing plates as described above. That is, two optically anisotropic layers can be provided on the liquid crystal cell side of the lower polarizing plate.

FIG. 8 shows a typical configuration diagram of the color liquid crystal display device of the present invention. In FIG. 8, a liquid crystal comprising a glass substrate 84a provided with a counter transparent electrode 82 and a color filter 85, a glass substrate 84b provided with a pixel electrode 83 and a TFT 86, and a twisted nematic liquid crystal 81 sealed between the two substrates. A pair of polarizing plates 87a and 87b provided on both sides of the cell and the liquid crystal cell constitute a color liquid crystal display device. Of these, 87b is the polarizing plate of the present invention, and 87a may be provided with an optically anisotropic layer as shown in the figure. Alternatively, as described above, the lower polarizing plate may be provided with two optically anisotropic layers.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

[0070]

EXAMPLE (Preparation of Coating Solution A for Antiglare Layer) A hard coat coating solution containing a titanium dioxide dispersion (KZ-7886A, JSR) was stirred in a mixed solvent of 104.1 g of cyclohexanone and 61.3 g of methyl ethyl ketone with an air disper.
217.0 g). The refractive index of the coating film obtained by applying this solution and curing with ultraviolet light was 1.61. Further, crosslinked polystyrene particles having an average particle size of 2 μm (trade name: SX-200H, Soken Chemical Co., Ltd.)
5g) and 5000 rpm at high speed disper
After stirring and dispersion for 1 hour, the mixture was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the antiglare layer.

(Preparation of Coating Solution B for Antiglare Layer) 125 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), bis (4-methacryloylthiophenyl) sulfide ( MPSMA, manufactured by Sumitomo Seika Co., Ltd.)
125 g was dissolved in 439 g of a mixed solvent of methyl ethyl ketone / cyclohexanone = 50/50% by weight. A solution prepared by dissolving 5.0 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and 3.0 g of a photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) in 49 g of methyl ethyl ketone was added to the obtained solution. added. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet light is 1.60.
Met. Further, 10 g of crosslinked polystyrene particles having an average particle size of 2 μm (trade name: SX-200H, manufactured by Soken Chemical Co., Ltd.) was added to this solution, and 500 g of high-speed disperser was used.
After stirring and dispersing at 0 rpm for 1 hour, the mixture was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the antiglare layer.

(Preparation of Coating Solution C for Anti-Glare Layer) A hard coat coating solution containing a titanium dioxide dispersion (KZ-7991, JSR) was stirred in a mixed solvent of 104.1 g of cyclohexanone and 61.3 g of methyl ethyl ketone with an air disper.
217.0 g). The coating film obtained by applying this solution and curing with ultraviolet light had a refractive index of 1.70. Further, crosslinked polystyrene particles having an average particle size of 2 μm (trade name: SX-200H, Soken Chemical Co., Ltd.)
5g) and 5000 rpm at high speed disper
After stirring and dispersion for 1 hour, the mixture was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the antiglare layer. This solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the hard coat layer.

(Preparation of Coating Solution for Hard Coat Layer) 250 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was added to 439 g of methyl ethyl ketone / cyclohexanone = 50/50 weight. % Of the mixed solvent. 7.5 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and a photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 5.0 were added to the obtained solution.
g was dissolved in 49 g of methyl ethyl ketone. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet light was 1.53. Further, the solution was added with a pore size of
Then, the mixture was filtered through a polypropylene filter of m to prepare a coating solution for a hard coat layer.

(Preparation of Coating Solution A for Low Refractive Index Layer) A thermally crosslinkable fluoropolymer having a refractive index of 1.46 (JN-722)
1. 200 g of methyl isobutyl ketone was added to 200 g of JSR Corporation, and the mixture was stirred and filtered with a polypropylene filter having a pore size of 1 μm to prepare a coating solution for a low refractive index layer.

(Preparation of Coating Solution B for Low Refractive Index Layer) A thermally crosslinkable fluoropolymer having a refractive index of 1.40 (JN-722)
3, 100 g of methyl isobutyl ketone was added to 500 g of JSR Corporation, and the mixture was stirred and filtered with a polypropylene filter having a pore size of 1 μm to prepare a coating solution for a low refractive index layer.

(Preparation of Coating Solution for Alignment Layer) Linear alkyl-modified polyvinyl alcohol (MP-203, Kuraray Co., Ltd.)
30 g of water, 130 g of water and 40 g of methanol were added thereto, followed by stirring and dissolution, followed by filtration with a polypropylene filter having a pore size of 30 μm to prepare a coating solution for an alignment layer.

(Preparation of Coating Solution A for Optically Anisotropic Layer) Compound No. TE-8 was used as a liquid crystalline discotic compound.
1.6 g of (R: 8, m = 4), phenoxydiethylene glycol acrylate (M-101, Toagosei Co., Ltd.)
0.4 g, cellulose acetate butyrate (CA)
B531-1, manufactured by Eastman Chemical Company) 0.05 g
After dissolving 0.01 g of a photopolymerization initiator (Irgacure-907, Ciba-Geigy) in 3.65 g of methyl ethyl ketone, the solution was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution A for an optically anisotropic layer. .

(Preparation of Coating Solution B for Optically Anisotropic Layer) Compound No. TE-8 was used as a liquid crystalline discotic compound.
1.8 g of (R: 8, m = 4), ethylene glycol-modified trimethylolpropane triacrylate (V # 36)
0, 0.2 g of Osaka Organic Chemical Industry Co., Ltd., 0.04 g of cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) and 0.06 g of photopolymerization initiator (Irgacure-907, manufactured by Ciba Geigy) And photosensitizer (Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.)
After dissolving 0.02 g in 3.43 g of methyl ethyl ketone, the solution was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating liquid B for an optically anisotropic layer.

(Preparation of Coating Solution C for Optically Anisotropic Layer) Compound No. TE-8 was used as a liquid crystalline discotic compound.
After dissolving 1.8 g of (R: 3) in 7.2 g of methyl ethyl ketone, the solution was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating liquid C for an optically anisotropic layer.

Example 1 (Preparation of anti-reflection film) Triacetyl cellulose film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.)
The coating solution A for an anti-glare layer was applied using a bar coater, dried at 120 ° C., and then illuminated at 400 mW / cm using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.). cm2, irradiation dose 300mJ / c
The coating layer is cured by irradiating ultraviolet rays having a thickness of 4 μm.
Was formed. The coating solution A for a low refractive index layer was coated thereon using a bar coater, dried at 80 ° C., and thermally crosslinked at 120 ° C. for 10 minutes to form a layer having a thickness of 0.1 μm.
By forming a low-refractive-index layer of 096 μm, a film having an antireflection layer was prepared.

(Preparation of Optical Compensation Film) The above coating solution for an alignment layer was applied to a 120 μm thick triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd.) having an undercoat layer of gelatin thin film (0.1 μm). After coating with a coater and drying at 60 ° C., rubbing treatment was performed to form an alignment layer having a thickness of 0.5 μm. The thickness of the alignment layer-attached triacetyl cellulose was measured using a micrometer, and the retardation from various directions was measured using an ellipsometer (AEP-100, manufactured by Shimadzu Corporation). d and ｛(nx +
ny) / 2−nz｝ × d, | nx−n
y | × d is 3 nm, {(nx + ny) / 2−nz} × d
Was 60 nm. That is, this triacetyl cellulose was a substantially negative uniaxial film, and the optical axis was substantially in the normal direction of the film. On the alignment layer, the optically anisotropic layer coating solution A was applied using a bar coater.
After drying for 3 minutes, the liquid crystal is aged for 3 minutes to align the discotic compound.
Illuminance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 60 W / cm.
2. An optical compensation film was prepared by irradiating an ultraviolet ray having an irradiation amount of 300 mJ / cm2 to cure the coating layer to form an optically anisotropic layer having a thickness of 1.8 μm.

(Preparation of Polarizing Plate) The antireflection film and the optical compensation film were saponified with a 1.5N NaOH aqueous solution, and a polarizing layer composed of stretched polyvinyl alcohol doped with iodine was added to the antireflection film and the optical compensation film. The polarizing plate of Example 1 was prepared by sandwiching and adhering between triacetyl cellulose surfaces.

Example 2 Triacetylcellulose film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.)
The above-mentioned coating solution for a hard coat layer is applied using a bar coater, dried at 120 ° C., and then cooled with a 160 W / cm air-cooled metal halide lamp (Eye Graphics Co., Ltd.)
Illuminance 400mW / cm2, irradiation amount 300
The coating layer was cured by irradiating ultraviolet rays of mJ / cm 2 to form a hard coat layer having a thickness of 4 μm. The anti-glare layer coating solution B was applied thereon using a bar coater, dried and cured under the same conditions as the hard coat layer to form an anti-glare layer having a thickness of about 1.5 μm. . The low refractive index layer coating solution A was applied thereon using a bar coater.
After drying at 0 ° C., it is further thermally crosslinked at 120 ° C. for 10 minutes to form a low refractive index layer having a thickness of 0.096 μm.
A film having an antireflection layer was prepared. A polarizing plate of Example 2 was prepared in the same manner as in Example 1 except for this antireflection film.

Example 3 Triacetylcellulose film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.)
The above-mentioned coating solution for a hard coat layer is applied using a bar coater, dried at 120 ° C., and then cooled with a 160 W / cm air-cooled metal halide lamp (Eye Graphics Co., Ltd.)
Illuminance 400mW / cm2, irradiation amount 300
The coating layer was cured by irradiating ultraviolet rays of mJ / cm 2 to form a hard coat layer having a thickness of 4 μm. The anti-glare layer coating solution C was applied thereon using a bar coater, dried and cured under the same conditions as the hard coat layer to form an anti-glare layer having a thickness of about 1.5 μm. . The low refractive index layer coating solution A was applied thereon using a bar coater.
After drying at 0 ° C., it is further thermally crosslinked at 120 ° C. for 10 minutes to form a low refractive index layer having a thickness of 0.096 μm.
A film having an antireflection layer was prepared. A polarizing plate of Example 3 was prepared in the same manner as in Example 1 except for this antireflection film.

Example 4 Triacetylcellulose film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.)
The above-mentioned coating solution for a hard coat layer is applied using a bar coater, dried at 120 ° C., and then cooled with a 160 W / cm air-cooled metal halide lamp (Eye Graphics Co., Ltd.)
Illuminance 400mW / cm2, irradiation amount 300
The coating layer was cured by irradiating ultraviolet rays of mJ / cm 2 to form a hard coat layer having a thickness of 4 μm. The anti-glare layer coating solution B was applied thereon using a bar coater, dried and cured under the same conditions as the hard coat layer to form an anti-glare layer having a thickness of about 1.5 μm. . The coating liquid B for a low refractive index layer was applied thereon using a bar coater.
After drying at 0 ° C., it is further thermally crosslinked at 120 ° C. for 10 minutes to form a low refractive index layer having a thickness of 0.096 μm.
A film having an antireflection layer was prepared. A polarizing plate of Example 4 was prepared in the same manner as Example 1 except for this antireflection film.

Example 5 The above-mentioned coating liquid B for an optically anisotropic layer was applied on the alignment layer of Example 1 using a bar coater.
After drying at 120 ° C., the mixture was further heated for 3 minutes to ripen the liquid crystal to align the discotic compound.
Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm with an illuminance of 400 mW
The applied layer was cured by irradiating ultraviolet rays having an irradiation amount of 300 mJ / cm 2 at a dose of 300 mJ / cm 2 to form an optically anisotropic layer having a thickness of 1.8 μm, thereby producing an optical compensation film. Example 5 was repeated in the same manner as in Example 1 except for the optical compensation film.
Was prepared.

Example 6 A commercially available polarizing plate (manufactured by Co., Ltd.) in which the triacetyl cellulose surfaces of the antireflection film and the optical compensation film of Example 1 were processed with an adhesive and triacetyl cellulose was used as a polarizing layer protective film. A polarizing plate of Example 6 was produced by bonding the two surfaces of the polarizing plate of the present invention (manufactured by Sanritz).

Example 7 The triacetyl cellulose surface of the optical compensation film of Example 1 was subjected to an adhesive treatment, and a polarizing layer protective film was formed on one surface of triacetyl cellulose and on the other surface an antireflection layer formed by vapor deposition. The polarizing plate of Example 7 was prepared by attaching the commercially available polarizing plate (manufactured by Sanritz Co., Ltd.) using the attached triacetyl cellulose to the triacetyl cellulose protective film side.

Comparative Example 1 Triacetylcellulose film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.)
The above-mentioned coating solution for a hard coat layer is applied using a bar coater, dried at 120 ° C., and then cooled with a 160 W / cm air-cooled metal halide lamp (Eye Graphics Co., Ltd.)
Illuminance 400mW / cm2, irradiation amount 300
The coating layer was cured by irradiating ultraviolet rays of mJ / cm 2 to form a hard coat layer having a thickness of 4 μm. A polarizing plate of Comparative Example 1 was prepared in the same manner as in Example 1, except that this hard coat film was used instead of the antireflection film.

Comparative Example 2 A polarizing plate of Comparative Example 2 was prepared in the same manner as in Example 3 except that an 80 μm-thick triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd.) was used instead of the optical compensation film. Created.

[Comparative Example 3] The above-mentioned coating liquid C for an optically anisotropic layer was applied on the alignment layer of Example 1 using a bar coater.
After drying at 180 ° C., further heating for 1 minute, ripening the liquid crystal to align the discotic compound, and then cooling to room temperature to form an optically anisotropic layer having a thickness of 1.0 μm. It was created. A polarizing plate of Comparative Example 7 was prepared in the same manner as in Example 3 except for this optical compensation film.

(Evaluation of antireflection film) The following items were evaluated for the obtained antireflection film. (1) Average reflectance 380-7 using a spectrophotometer (manufactured by JASCO Corporation)
The spectral reflectance at an incident angle of 5 ° was measured in a wavelength region of 80 nm. The average reflectance of 450 to 650 nm was used for the results. (2) Haze The haze of the obtained film was measured using a haze meter MODEL.
It measured using 1001DP (made by Nippon Denshoku Industries Co., Ltd.). (3) Pencil hardness evaluation Pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. Antireflection film at a temperature of 25 ° C and a humidity of 60
% RH for 2 hours, using a 3H test pencil specified in JIS S 6006, with a load of 1 kg, and no scratches are observed in the evaluation of n = 5: ○ In the evaluation of n = 5 1 or 2 flaws: Δ 3 or more flaws in evaluation of n = 5: × (4) Evaluation of contact angle and fingerprint adhesion
After adjusting the humidity at 60% RH for 2 hours, the contact angle to water was measured. After attaching a fingerprint to the sample surface, the sample was wiped off with a cleaning cloth to observe the state, and the fingerprint adhesion was evaluated as follows. Fingerprints can be completely wiped off: ○ Fingerprints can be seen slightly: △ Fingerprints can hardly be wiped off: ×

(5) Measurement of dynamic friction coefficient The dynamic friction coefficient was evaluated as an index of the surface slip property. The coefficient of kinetic friction was adjusted at 25 ° C. and a relative humidity of 60% for 2 hours, and then 5 mmφ using a HEIDON-14 kinetic friction measuring instrument.
Stainless steel ball, load 100g, speed 60cm / min
The value measured in was used. (6) Evaluation of antiglare property A bare fluorescent lamp (8000 cd / m2) without a louver was projected on the prepared antiglare film, and the degree of blurring of the reflected image was evaluated according to the following criteria. The outline of the fluorescent lamp is not known at all: ◎ The outline of the fluorescent lamp is slightly recognized: ○ The fluorescent lamp is blurred, but the outline can be identified: △ The fluorescent lamp is hardly blurred: ×

(Evaluation of Optical Compensation Film) The following items were evaluated for the obtained optical compensation film. (1) Haze The haze of the obtained film was measured using a haze meter MODEL.
It measured using 1001DP (made by Nippon Denshoku Industries Co., Ltd.). (2) Change of optical axis and tilt angle For this optical compensation film, retardation from all directions on a plane including the rubbing axis and perpendicular to the optical compensation film surface is measured by an ellipsometer (AEP-100,
(Manufactured by Shimadzu Corporation), and the retardation of only the support and the alignment layer after removing the optically anisotropic layer at the measurement portion was measured in the same manner. The optical characteristics of only the optically anisotropic layer (measurement angle dependence of retardation) were obtained from these two measured values, and the presence or absence of the optical axis was examined with the direction of zero retardation as the optical axis. Further, the inclination (change in inclination angle) of the discotic compound from the surface of the support was calculated by fitting optical characteristics. (3) Size of domain The size of the domain formed in the optically anisotropic layer was measured by observation with a polarizing microscope.

Table 1 shows the results of Examples and Comparative Examples.

[0096]

[Table 1] *… Mono = Mono Domain

Next, Examples 1, 5, 6, and 7 and Comparative Example 1
A liquid crystal display device as shown in FIG. The same optical compensation film as used in each example was used for the optical compensation film of the front polarizing plate. The liquid crystal cell has a nematic liquid crystal with a twist angle of 90 ° and 4.5.
It was sandwiched so as to have a gap size of μm. As shown in FIG. 9, the angle 91 between the rubbing direction 71a of the lower optical compensation film and the rubbing direction 72a of the lower substrate is 180.
The angle 92 formed between the rubbing direction 71b of the upper optical compensation film and the rubbing direction 72b of the upper substrate was 180 degrees, and they were arranged as shown in FIG.

(Evaluation of Liquid Crystal Display Device) The following items were evaluated for the obtained liquid crystal display device. (1) Front Contrast A rectangular wave voltage of 55 Hz is applied from 0 to 5 V to the obtained TN-LCD, and the contrast in the front direction is measured by a spectrometer (L).
CD-5000, manufactured by Otsuka Electronics Co., Ltd.). (2) Viewing angle A 55 Hz rectangular wave voltage of 0 to 5 V is applied to the obtained TN-LCD, and the contrast in the direction inclined upward / downward and left / right is measured by a spectrometer (LCD-5000, Otsuka Electronics Co., Ltd.). (Manufactured by Co., Ltd.). Viewing angle is contrast 1
The angle range was 0 or more. (3) Visibility in a Room The obtained TN-LCD was visually evaluated for blackness in black display in a room as follows. ◎: Black is dark enough to not disturb the brightness of the room. ○: Black is sufficiently dark, affected by the brightness of the room. △: Black is slightly worse in oblique directions. X: Black is darker. bad

Table 2 shows the results of Examples and Comparative Examples.

[0100]

[Table 2]

Next, a TFT type liquid crystal color television 6E-C
The polarizing plate of No. 3 (manufactured by Sharp Corporation) was peeled off, and a color liquid crystal display device was prepared using the polarizing plates of Examples 1, 5, 6, and 7 and Comparative Examples 1 to 3.

(Evaluation of Color Liquid Crystal Display) The following items were evaluated for the obtained liquid crystal display. (1) Viewing angle The obtained color liquid crystal display device performs white display and black display, and determines the contrast in the direction inclined upward / downward and left / right by a spectrometer (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.). It measured using. The viewing angle was in an angle range where the contrast was 10 or more.

Table 3 shows the results of Examples and Comparative Examples.

[0104]

[Table 3]

[0105]

According to the polarizing plate of the present invention having an optical compensation function and an antireflection function, a liquid crystal display device and a color liquid crystal display device using the same, it is possible to improve the deterioration of display quality due to the reflection of external light and to improve the TN. By expanding the viewing angles of the mode liquid crystal display device and the color liquid crystal display device, a liquid crystal display device having excellent display quality in all directions can be provided. In addition, by using the method of coating which is excellent in mass productivity, they can be easily and stably manufactured, and the polarizing plate having the optical compensation ability and the antireflection ability of the present invention can be supplied at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a typical configuration of a conventional liquid crystal display device.

FIG. 2 is a schematic sectional view showing a typical layer configuration of an optical compensation film.

FIG. 3 is a diagram illustrating a relationship between a typical configuration of an optical compensation film and a triaxial principal refractive index.

FIG. 4 is a schematic sectional view showing a typical layer configuration of an antireflection film.

FIG. 5 is a schematic cross-sectional view showing a typical layer configuration of a polarizing plate having optical compensation ability and antireflection ability.

FIG. 6 is a diagram showing a typical configuration of a liquid crystal display device using the polarizing plate of the present invention.

FIG. 7 is a diagram showing a typical structure of a liquid crystal display device of the present invention.

FIG. 8 is a diagram showing a typical structure of a color liquid crystal display device of the present invention.

FIG. 9 is a diagram showing a typical configuration when FIG. 7 is viewed from a film normal direction.

DESCRIPTION OF SYMBOLS 11 Reflective sheet 12 Light guide plate 13 Scattering sheet 14 Light control film 15 Back polarizer 16 Front polarizer 17 Liquid crystal cell 18 Cold cathode fluorescent tube 19 Reflective sheets 21 and 41 Transparent support 22 Alignment layer 23 Optical anisotropy Layers 24a, 24b, 24c Liquid crystalline discotic compound 25 Normal direction of transparent support 31 Rubbing direction 32 Angle between direction showing minimum value of absolute retardation and normal direction of transparent support 42 Antiglare layer 43 Low refractive index layer 44 Particle 51 Polarizing layer 52, 62a, 62b Optical compensation layer (film) 53, 61 Antireflection layer (film) 63 Liquid crystal cell 64 Adhesive layer 71a, 71b Rubbing direction of optical compensation film 72a, 72b Liquid crystal Rubbing direction of cell 73a, 73b Transmission direction of polarizing layer 74 Backlight 81 Twist arrangement Nematic liquid crystal molecules 82 Opposing transparent electrode 83 Pixel electrode 84a, 84b Glass substrate 85 Color filter 86 TFT 87a Lower polarizing plate 87b Upper polarizing plate 91, 92 The angle between the rubbing direction of the optical compensation film and the rubbing direction of the glass substrate.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Atsushi Watanabe, 210 Nakanuma, Minamiashigara, Kanagawa Prefecture Fuji Photo Film Co., Ltd. F-term (reference) 2H049 BA06 BA22 BA25 BA27 BB03 BB62 BB63 BB65 BC02 BC04 BC05 BC06 BC08 BC14 BC22 2H091 FA08X FA08Z FA11X FA37X FB02 FC22 FC23 FD01 FD06 GA06 HA07 LA03 LA12 LA19 2K009 AA02 BB12 BB13 BB14 BB22 BB24 BB28 CC22 CC23 CC24 DD02

Claims (16)

[Claims] 1. A polarizing plate having a polarizing layer sandwiched between two transparent supports, wherein one of the transparent supports comprises an optically anisotropic layer on the surface of the other side opposite to the polarizing layer. A polarizing plate having an optical compensation layer, and further having an antireflection layer on the surface of the other transparent support opposite to the polarizing layer, wherein the optically anisotropic layer comprises a compound having a discotic structural unit. A layer having a negative birefringence, wherein the disc surface of the discotic structure unit is inclined with respect to the transparent support surface, and the angle between the disc surface of the discotic structure unit and the transparent support surface is an optical difference. A polarizing plate characterized in that it changes in the depth direction of one of the layers. 2. The polarizing plate according to claim 1, wherein the angle increases as the distance of the optically anisotropic layer from the support surface side increases. 3. The polarizing plate according to claim 1, wherein the optically anisotropic layer further contains a cellulose ester. 4. The transparent support on the side of the optically anisotropic layer has optically negative uniaxiality, has an optical axis in a direction normal to the surface of the transparent support, and further satisfies the following conditions: The polarizing plate according to claim 1. ## EQU1 ## 20 ≦ {(nx + ny) / 2−nz} × d ≦
400 (d: thickness of optical compensation layer) 5. The polarizing plate according to claim 1, wherein an alignment layer is formed between the optically anisotropic layer and the transparent support. 6. The polarizing plate according to claim 5, wherein the alignment layer comprises a cured film of a polymer. 7. The polarizing plate according to claim 1, wherein the optically anisotropic layer is a monodomain or has a large number of domains having a size of 0.1 μm or less. 8. The method according to claim 1, wherein the anti-reflection layer comprises at least one
An antiglare antireflection layer including a low refractive index layer made of a fluorine-containing compound having a refractive index of 1.38 to 1.49, wherein the refractive index between the substrate and the low refractive index layer is 1. 57 to 2.00
The polarizing plate according to claim 1, further comprising an antiglare layer comprising a binder and particles. 9. The low refractive index layer is made of a fluorine-containing compound which is crosslinked by heat or ionizing radiation having a dynamic friction coefficient of 0.03 to 0.15 and a contact angle to water of 90 to 120 °. 9. The polarizing plate according to 8. 10. The polarizing plate according to claim 8, wherein in the antiglare layer, a difference in refractive index between the particles and the binder is less than 0.05. 11. The polarizing plate according to claim 8, wherein the particles have an average particle size of 1 to 10 μm. 12. The binder of the antiglare layer has a refractive index of 1.5.
The polarizing plate according to claim 8, which is a heat or ionizing radiation cured product of a mixture of a high refractive index monomer having a refractive index of 7 to 2.00 and a monomer having two or more ethylenically unsaturated groups. 13. The binder of the antiglare layer is made of Al, Zr, Z
9. A heat or ionizing radiation cured product of a mixture of ultrafine particles of a metal selected from n, Ti, In, and Sn and a monomer having two or more ethylenically unsaturated groups. Polarizing plate. 14. An antiglare layer having an average particle size of 0.01 to 1.
0 μm, refractive index 1.35 to 1.65 or 2.00
To 3.00, and the difference from the refractive index of the binder is 0.3.
9. The polarizing plate according to claim 8, comprising scattering particles having a particle size of 03 or more. 15. The polarizing plate according to claim 1, wherein
A liquid crystal display device comprising: a polarizing plate on a display side among two polarizing plates disposed on both sides of a liquid crystal cell; and an optically anisotropic layer disposed toward the liquid crystal cell. 16. A liquid crystal cell comprising a pair of substrates having a transparent electrode, a pixel electrode and a color filter, and a twisted nematic liquid crystal sealed between the substrates, and a pair of optical compensation provided on both sides of the liquid crystal cell. 15. A color liquid crystal display device comprising a sheet and a pair of polarizing plates disposed outside thereof, wherein the polarizing plate according to claim 1 is used as a display-side optical compensation sheet and a polarizing plate of a liquid crystal cell, and the optically anisotropic film is used. The liquid crystal cell side, and further comprising an optically anisotropic layer having a negative birefringence made of a compound having a discotic structural unit on the backlight side of the liquid crystal cell, wherein a circle of the discotic structural unit is provided. The disc surface is inclined with respect to the transparent support surface, and the angle between the disc surface of the discotic structure unit and the transparent support surface changes in the depth direction of the optically anisotropic layer. A liquid crystal display device having an optical compensation sheet.