JP2003121618A - Light scattering film, method for manufacturing light scattering film, polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wide viewing angle of a liquid crystal display device by using a light scattering film, in particular, to prevent the inversion of gradation in the downward direction of the panel and the reflection of external light. SOLUTION: In the light scattering film having a light scattering layer on a transparent base material, the light scattering layer is made of a light transmitting resin and light transmitting fine particles. The thickness of the light scattering layer is controlled to 2.0 to 6.0 μm and the light transmitting resin is made to permeate the transparent base material to 0.01 to 1 μm depth from the surface of the base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-scattering film having a light-scattering layer containing transparent fine particles on a transparent substrate, and a method for producing the same. The present invention also relates to a light-scattering film that improves the display quality of a liquid crystal display device, and a polarizing plate using the same. Furthermore, the present invention also relates to a liquid crystal display device having improved display quality.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device comprises a polarizing plate and a liquid crystal cell. The display quality defects of the liquid crystal display device are a narrow viewing angle and reflection of external light. Regarding the viewing angle, in the TN mode TFT liquid crystal display device which is the mainstream at present, JP-A-8-50206 and JP-A-7-
191217 and European Patent 0911656.
By inserting an optical compensation film between the polarizing plate and the liquid crystal cell as described in the specification A2, a liquid crystal display device having an extremely wide viewing angle is realized. However, the liquid crystal display device still has a problem that gray scale inversion occurs in the downward direction of the panal. To solve this problem, a light diffusing means is disclosed in Japanese Patent No. 2822983, an optical axis conversion plate is disclosed in JP 2001-33783 A, and an optical means for diffusing outgoing light is disclosed in JP 2001-56461 A. It has been proposed that the display quality is remarkably improved by providing the display surface on the viewing side. However, the specific means described in these is a light diffusing means having a highly controlled lens structure or a diffractive structure, which is expensive and very difficult to mass-produce.

As a light-scattering film which is inexpensive and can be mass-produced, as disclosed in, for example, JP-A-6-18706 and JP-A-10-20103, silicon dioxide is formed on the surface of a transparent base film. What is formed by applying a resin containing a filler such as (silica), JP-A-11-
160505, JP-A-11-305010, JP-A-11-326608, JP-A-2000-
No. 121809, No. 2000-180611, and No. 2000-338310. However, even if the light-scattering films described in these specifications are used, the display quality is improved only slightly.

Further, there is a problem in the adhesion between the fine particles (filler such as silicon dioxide) used as the light scattering means and the transparent substrate film. For example, when the user wipes off the dirt on the liquid crystal display surface, the light diffusion layer containing fine particles and the transparent substrate film may be separated.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light scattering film with improved durability.
Further, an object of the present invention is to increase the viewing angle (especially the downward viewing angle) without increasing the thickness of the liquid crystal panel, and to reduce the contrast, gradation or black / white inversion, and hue change due to the viewing angle change. Rarely happens,
Another object of the present invention is to provide a polarizing plate having improved durability and a liquid crystal display device using the same.

[0006]

The object of the present invention is to provide a light-scattering film of the following (1) to (4) and the following (5) and (6).
The method for producing a light-scattering film described in (1), the polarizing plate described in (7) to (9) below, and the liquid crystal display device described in (10) below. (1) A light-scattering film having a light-scattering layer on a transparent substrate, wherein the light-scattering layer comprises a light-transmitting resin and light-transmitting fine particles, and the light-scattering layer has a thickness of 2.0 to 6.0 μm. And the transparent resin is 0.01 to 1 from the surface of the transparent substrate.
A light-scattering film that is soaked to a depth of μm. (2) The light-scattering film according to (1), wherein the light-scattering layer has a surface roughness of 0.05 μm to 0.18 μm. (3) The light scattering layer has a haze value of 40% or more (1)
Alternatively, the light-scattering film according to (2). (4) The light-scattering film according to any one of (1) to (3), wherein a low refractive index layer is provided on the light-scattering layer.

(5) A translucent resin and translucent fine particles are dissolved or dispersed in a mixed solvent containing a solvent in which a transparent substrate is soluble and a solvent in which a transparent substrate is insoluble to prepare a coating solution. The step of applying, the step of applying the coating liquid on the transparent substrate, and
A method for producing a light-scattering film, which comprises a step of forming a light-scattering layer by drying, wherein the light-scattering layer has a thickness of 2.0 to 6.0 μm, and the translucent resin is a transparent substrate. A method for producing a light-scattering film, which is characterized in that it penetrates to a depth of 0.01 to 1 μm from the surface. (6) The method for producing a light-scattering film according to (5), wherein the transparent substrate is a cellulose acetate film, and the solvent in which the transparent substrate is dissolved is ketone.

(7) A polarizing plate in which both sides of a polarizing film are sandwiched between two protective films, and one protective film is
A polarizing plate which is the light-scattering film according to any one of (1) to (4). (8) A polarizing plate having the light-scattering film according to any one of (1) to (4), a polarizing film, a transparent support, and an optically anisotropic layer composed of a liquid crystalline compound in this order. . (9) The polarizing plate according to (8), wherein the liquid crystalline compound is a discotic compound. (10) A liquid crystal display device in which both sides of a liquid crystal cell are sandwiched between two polarizing plates, and the polarizing plate on the display surface side is the polarizing plate according to any one of (7) to (9). Liquid crystal display device.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventor has succeeded in obtaining a light-scattering film having extremely high durability by impregnating a transparent resin to a depth of 0.01 to 1 μm from the surface of a transparent substrate. did.

The light emitted from the backlight is diffused by the light scattering film provided on the surface of the polarizing plate on the viewing side, and the viewing angle characteristic is improved. However, if it is diffused too much, backscattering becomes large and the front luminance decreases, or there is a problem that image scattering is deteriorated due to too much scattering. Therefore, the internal scattering haze is preferably 30% to 80%, and most preferably 35% to 70%. As a method for increasing the internal scattering haze, there are methods such as increasing the concentration of particles having a particle diameter of 0.5 μm to 2.0 μm, increasing the film thickness, and further increasing the refractive index of the particles. Apart from this, it is also necessary to provide a surface haze due to surface irregularities from the viewpoint of visibility, and in the presence of the internal scattering haze and the surface haze, a haze value of 40% or more provides a viewing angle improving effect. Is exhibited, preferably 40% to 90%, 45
% To 80% is more preferable, and 48% to 70% is the most preferable.

[0011] It was common knowledge that the antiglare property, that is, the reflection of external light, was correlated with the surface roughness, and the reflection decreased as the roughness increased, but according to the inventor's earnest research, It was found that there was a correlation between the average value of the angular distribution from the surface of the surface irregularities or the peak angle. That is, even if the surface roughness is small, the reflection of external light can be prevented. Conventionally, when the surface is roughened, the reflection of external light is improved, but instead, there is a problem that the image is blurred or the entire image becomes whitish. The problem of this trade-off can be solved by using the light-scattering film or the polarizing plate of the present invention.

In order to prevent external light from being reflected while maintaining high display quality (no image blurring or whitishness), the average value of the angular distribution from the surface of the unevenness of the light scattering layer is determined. It is preferably 1.5 ° to 5 °, and 2 ° to 4.5.
It is more preferable that the angle is °. Further, the peak value of the angular distribution from the uneven surface of the light scattering layer is 0.4 ° to 1.4 °.
The angle is preferably below, and more preferably 0.5 ° to 1.2 °. Further, the surface roughness of the light scattering layer is preferably 0.05 μm to 0.18 μm, more preferably 0.16 μm or less, and 0.1
Most preferably, it is 4 μm or less. The angle distribution from the surface of the unevenness of the surface is shown by Surfa for the manufactured light scattering film.
ce Explore SX-520 system (manufactured by Ryoka System Co., Ltd., interference microscope (manufactured by Nikon MM-40
/ 60 series objective lens: Two-beam interference objective lens,
Halogen lamp used, CCD camera: 640 x 48
It is a value measured using the micro map software of 0)).

The surface roughness of the light-scattering layer can be controlled by the size and amount of the particles in the light-scattering layer, and the translucent resin (binder) ratio (thickness of the light-scattering layer). When the particle size has two or more peaks, it corresponds to the size of the peak having the larger particle size. The relationship between the particle size (dp) and the layer thickness (db) is dp−1.0 μm ≦ db ≦ dp +
1.5 μm is preferable, and dp−0.5 μm ≦ db ≦ dp
+1.0 μm is more preferable. The concentration of particles is preferably 1% by mass to 15% by mass, more preferably 3% by mass to 12% by mass, based on the binder.
In terms of production of the particle size, the practical range is preferably 2.0 μm to 5.5 μm, and more preferably 2.5 μm to 5.0 μm. By increasing the binder ratio, it becomes difficult for particles to project onto the light scattering layer, and the surface roughness can be reduced. As a method of increasing the binder ratio, a method of increasing the binder ratio in the coating liquid, and the solvent composition of the coating liquid when coating, and drying conditions,
This can be achieved by controlling the amount of binder soaking into the transparent substrate. From the viewpoint of reducing the surface roughness, it is preferable that the drying is delayed so that the coating layer can be sufficiently leveled (smoothed), and the solvent composition is less likely to soak into the transparent substrate (do not dissolve). However, from the viewpoint of adhesion between the transparent substrate and the light-scattering layer, it is necessary to use a mixture with a solvent that permeates (dissolves) the transparent substrate to some extent.

Specifically, the temperature until solvent drying is 20 ° C.
To 40 ° C., and the most preferable combination as the solvent composition is the solvent (A) for dissolving the transparent base film,
It is preferable to select methyl ethyl ketone, which dries relatively quickly, and to select methyl isobutyl ketone, which is the same ketone solvent, as the solvent (B) that does not dissolve the transparent substrate film. Furthermore, the mass ratio (A / B) of each total amount is
5/95 to 30/70 are preferable, and 8/82 to 25
To 75 are more preferable.

In a preferred embodiment of the light-scattering film of the present invention, at least one light-scattering layer is provided on a triacetyl cellulose transparent support, and at least one low refractive index layer is further provided thereon.

The basic structure of the light-scattering film of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 is an example of the light-scattering film of the present invention. The light-scattering film 1 comprises a transparent support 2 made of triacetyl cellulose, a light-scattering layer 3, and a low-refractive index layer 4 in this order. Have. Matt particles 5 are dispersed in the light scattering layer 3. The light scattering layer 3 may be composed of a plurality of layers.

The transparent resin of the light scattering layer preferably has a refractive index of 1.51 to 2.00, and the low refractive index layer preferably has a refractive index of 1.35 to 1.45. The refractive index of triacetyl cellulose preferably used as the transparent support is 1.48. By thus increasing the refractive index of the light scattering layer, the low refractive index layer has a refractive index of 1.35 to 1.
Even in the range of 45, the antireflection effect is excellent. Therefore, if the refractive index of the light scattering layer is too small, the antireflection property is deteriorated, and if it is too large, the tint of the reflected light becomes strong, which is not preferable.

<Light-scattering layer> The light-scattering layer is composed of the matte particles and a light-transmitting resin. This makes the haze value 40% or more as described above. The higher the refractive index of the translucent resin, the lower the reflectance that can be realized by combining it with the antireflection layer described later. Therefore, for example, a resin (average refractive index 1.62) made of zirconia-dispersed DPHA monomer should be used. preferable. The matte particles are preferably translucent fine particles, and in order to obtain an effect suitable for the present invention, 2
It is preferable to use translucent fine particles having a particle size of at least one kind. In this case, the first translucent fine particles 1 are translucent resin,
For example, the second translucent fine particles 2 are made of polymethylmethacrylate fine particles (average particle diameter 1.5 μm, refractive index 1.49), and the second translucent fine particles 2 are the same as the translucent resin (polymethylmethacrylate fine particles (average particle diameter 3.0 μm). , Refractive index 1.4
9).

It is preferable that the difference in refractive index between the transparent fine particles 1 and 2 and the transparent resin forming the entire light scattering layer is 0.02 or more and 0.15 or less. The refractive index difference is 0.
When it is less than 02, the difference in the refractive index between the two is too small to obtain the light diffusion effect, and when the difference in the refractive index is larger than 0.15, the light diffusion is too high and the film as a whole is too high. Is bleached. The refractive index difference is 0.0
3 or more and 0.13 or less are more preferable, 0.04 or more,
The best value is 0.10 or less. The particle size of the translucent fine particles 1 is preferably 0.5 μm to 2.0 μm. The reason is to obtain the angular distribution of light scattering suitable for the present invention.

In the present invention, in order to improve the display quality (improve the downward viewing angle), it is necessary to diffuse the incident light to some extent. The greater the diffusion effect is, the more the viewing angle characteristics are improved. However, in order to maintain the front brightness in terms of display quality, it is necessary to increase the transmittance as much as possible. When the particle size is 0.5 μm or less, the scattering effect is large and the viewing angle characteristics are dramatically improved, but the backscattering is large and the brightness is drastically reduced. On the other hand, when it is 2.0 μm or more, the scattering effect becomes small, and the improvement of the viewing angle characteristic becomes small. Therefore, the particle size is preferably 0.6 μm to 1.8 μm, and is 0.7 μm.
Most preferably, it is m to 1.7 μm.

The particle diameter of the transparent fine particles 2 is most preferably 2.5 μm to 5.0 μm as described above. That is to obtain the surface scattering suitable for the present invention.

In the translucent fine particles, two or more kinds of translucent fine particles having different particle diameters are used, and the translucent fine particles are mixed so that the visual angle characteristic relating to the display quality and the reflection of external light can be obtained. Each can be optimized independently, a fine setting can be made by the mixing ratio of the translucent fine particles, control can be performed as compared with the case of one type, and various designs are facilitated.

The transparent fine particles 1 and 2 may be monodisperse organic fine particles or inorganic fine particles. The more uniform the particle size is, the less the scattering characteristics are, and the easier the design of the haze value is. As the light-transparent fine particles, plastic beads are preferable, and those having a particularly high degree of transparency and having a difference in refractive index with the light-transmissive resin as described above are preferable. As the plastic beads, polymethylmethacrylate beads (refractive index 1.49), acrylic-styrene copolymer beads (refractive index 1.55), melamine beads (refractive index 1.57), polycarbonate beads (refractive index 1.57). ), Styrene beads (refractive index 1.
60), crosslinked polystyrene beads (refractive index 1.61),
Polyvinyl chloride beads (refractive index 1.60), benzoguanamine-melamine formaldehyde beads (refractive index 1.
68) and the like are used.

The particle size of the plastic beads may be 0.5 to 5 μm, as described above, and may be appropriately selected and used.
The content is preferably 5 to 80 parts by mass, more preferably 15 to 70 parts by mass, and most preferably 30 to 60 parts by mass based on 100 parts by mass of the translucent resin.

In the case of the translucent fine particles as described above, the translucent fine particles tend to settle in the resin composition (translucent resin), so an inorganic filler such as silica is added to prevent settling. May be. As the amount of the inorganic filler added increases, it is more effective in preventing the translucent fine particles from settling, but it adversely affects the transparency of the coating film. Therefore, the particle size is preferably 0.5 μm.
The following inorganic fillers may be contained in an amount of less than 0.1% by mass with respect to the translucent resin so as not to impair the transparency of the coating film.

The translucent resin is mainly a resin which is cured by ultraviolet rays or electron beams, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin with a thermoplastic resin and a solvent, and a thermosetting resin. Kind is used. The thickness of the light-scattering layer is usually about 0.5 μm to 50 μm, preferably 1 μm to 20 μm, more preferably 2 μm to
The thickness is preferably 10 μm, most preferably 3 μm to 7 μm. The refractive index of the translucent resin is preferably 1.51 to
It is 2.00, more preferably 1.53 to 1.95, still more preferably 1.57 to 1.90, and particularly preferably 1.64 to 1.80. The refractive index of the transparent resin is a value measured without the transparent fine particles. If the refractive index is too small, the antireflection property will decrease. Further, if it is too large, the tint of reflected light becomes strong, which is not preferable.

The binder used for the translucent resin is preferably a polymer having a saturated hydrocarbon or a polyether as the main chain, and more preferably a polymer having a saturated hydrocarbon as the main chain. Further, the binder 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, it is preferable to use a monomer having two or more ethylenically unsaturated groups.

Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexanediene). Acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,3,5-
Cyclohexanetriol trimethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (Eg, divinyl sulfone), acrylamide (eg, methylenebisacrylamide) and methacrylamide. At least 3 of these
An acrylate or methacrylate monomer having one functional group, and further an acrylate monomer having at least five functional groups are preferable from the viewpoint of film hardness, that is, scratch resistance. A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate is commercially available, and particularly preferably used.

These monomers having an ethylenically unsaturated group can be cured with a polymerization reaction by ionizing radiation or heat after being dissolved, coated and dried in a solvent together with various polymerization initiators and other additives.

Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder 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, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. You may use the functional group which shows crosslinkability as a result of a decomposition reaction like a block isocyanate group. That is, in the present invention, the crosslinkable functional group does not immediately show a reaction,
It may exhibit reactivity as a result of decomposition. The binder having these crosslinkable functional groups can form a crosslinked structure by heating after coating.

The translucent resin is preferably formed of a monomer having a high refractive index and / or ultrafine particles of a metal oxide having a high refractive index, in addition to the binder polymer. Examples of high refractive index monomers include bis (4
-Methacryloylthiophenyl) sulfide, vinylnaphthalene, vinylphenyl sulfide, 4-methacryloxyphenyl-4'-methoxyphenyl thioether and the like. Examples of the metal oxide ultrafine particles having a high refractive index include particles having a particle size of 100 nm or less, preferably 50 nm or less, which is made of at least one oxide selected from zirconium, titanium, aluminum, indium, zinc, tin and antimony. It is preferable to contain fine particles. As the metal oxide ultrafine particles having a high refractive index, Al, Z
Ultrafine oxide particles of at least one metal selected from r, Zn, Ti, In and Sn are preferable, and specific examples thereof include ZrO ₂ , TiO ₂ , Al ₂ O ₃ , In ₂ O ₃ and Zn.
_{O, SnO 2, Sb 2 O} 3, ITO , and the like. Among these, ZrO ₂ is particularly preferably used. The addition amount of the high refractive index monomer and the metal oxide ultrafine particles is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass based on the total mass of the translucent resin.

When the translucent resin and the transparent substrate film are in contact with each other, the solvent of the coating solution for forming the translucent resin has both the antiglare property and the adhesion between the support and the antiglare layer. To achieve this, the transparent substrate film (for example, triacetyl cellulose support) is composed of at least one kind of solvent and the transparent substrate film is not dissolved. More preferably, at least one of the solvents that does not dissolve the transparent substrate film,
It is preferable that it has a boiling point higher than that of at least one solvent that dissolves the transparent substrate film. More preferably, the solvent having the highest boiling point among the solvents that does not dissolve the transparent substrate film and the solvent having the highest boiling point among the solvents that dissolves the transparent substrate film have a boiling point temperature difference of 30 ° C. or more. Yes, and most preferably 50 ° C. or higher.

The solvent for dissolving the transparent base film (preferably triacetyl cellulose) has a carbon number of 3 to
12 ethers: specifically, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3
-Dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, and other ketones having 3 to 12 carbon atoms: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone , Cyclohexanone, methylcyclohexanone, methylcyclohexanone, etc., having 3 to 12 carbon atoms: Specifically, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, propionate ethyl , N-pentyl acetate, and γ-ptyrolactone,

Organic solvent having two or more kinds of functional groups: Specifically, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2 -Propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate and the like. These can be used alone or in combination of two or more. As the solvent that dissolves the transparent substrate, a ketone solvent is preferable.

As a solvent that does not dissolve the transparent base film (preferably triacetyl cellulose), methanol,
Ethanol, 1-propanol, 2-propanol, 1
-Butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol,
Examples thereof include cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone and 4-heptanone. These can be used alone or in combination of two or more.

The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the transparent substrate film and the total amount (B) of the solvent that does not dissolve the transparent substrate film is 1/99 to 50/50.
Is more preferable, 2/98 to 40/60 is more preferable, and 15/85 to 30/70 is still more preferable.

As a method for curing the above-mentioned ionizing radiation-curable resin composition, a conventional curing method for the above-mentioned ionizing radiation-curable resin composition, that is, irradiation with an electron beam or an ultraviolet ray can be used.

For example, in the case of electron beam curing, it is emitted from various electron beam accelerators such as Cockroff-Walton type, Van de Graaff type, resonance transformer type, insulating core transformer type, linear type, dynamitron type and high frequency type. 50-1000 KeV,
An electron beam or the like having an energy of 100 to 300 KeV is preferably used, and in the case of ultraviolet curing, ultraviolet rays or the like emitted from light rays such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, carbon arc, xenon arc, and a metal halide lamp can be used. .

[Low Refractive Index Layer] The low refractive index layer is provided as an antireflection layer on the outermost layer on the side where the light scattering layer is provided on the support for the purpose of imparting antireflection ability. The refractive index of the low refractive index layer is preferably 1.35 to 1.45 as described above. The refractive index of the low refractive index layer preferably satisfies the following mathematical formula (I). (Mλ / 4) × 0.7 <n ₁ d ₁ <(mλ / 4) × 1.3 Formula (I) In the formula, m is a positive odd number (generally 1), and n ₁ has low refraction. Is the refractive index of the low refractive index layer, and d ₁ is the film thickness (nm) of the low refractive index layer. Λ is the wavelength of visible light,
The value is in the range of 50 to 650 (nm). Note that satisfying the above mathematical expression (I) means that there is m (a positive odd number, usually 1) that satisfies the mathematical expression (I) in the above wavelength range.

For the low refractive index layer of the present invention, a fluorine-containing resin obtained by curing a thermosetting or ionizing radiation-curable crosslinkable fluorine-containing compound is used. As a result, the scratch resistance is excellent even when used as the outermost layer, as compared with the low refractive index layer using magnesium fluoride or calcium fluoride. The heat-curable or ionizing radiation-curable crosslinkable fluorine-containing compound preferably has a refractive index of 1.35 or more and 1.45 or less. The dynamic friction coefficient of the cured fluororesin is preferably 0.03 to
0.15, the contact angle to water is preferably 90 to 120
It is degree. As such a crosslinkable fluorine-containing compound,
In addition to a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane), a fluorine-containing monomer and a monomer for imparting a crosslinkable group are contained as constituent units. Fluorine copolymers may be mentioned.

Specific examples of the fluorine-containing monomer unit include:
For example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.), a portion of (meth) acrylic acid or Completely fluorinated alkyl ester derivatives (eg, biscoat 6F
M (Osaka Organic Chemical) and M-2020 (Daikin)
Etc.), fully or partially fluorinated vinyl ethers and the like.

Examples of the monomer for imparting a crosslinkable group include a (meth) acrylate monomer having a crosslinkable functional group in the molecule such as glycidyl methacrylate, as well as a carboxyl group, a hydroxyl group, an amino group and a sulfonic acid group. Examples thereof include (meth) acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.). The latter is after copolymerization,
It is disclosed in JP-A-10-25388 and JP-A-10-147739 that a crosslinked structure can be introduced.

For the low refractive index layer, not only a copolymer of the above-mentioned fluorine-containing monomer and a monomer for imparting a crosslinkable group, but also a polymer obtained by copolymerizing this with another monomer may be used. Other monomers that may be copolymerized are not particularly limited, and examples thereof include olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic acid esters (methyl acrylate, methyl acrylate, ethyl acrylate). , 2-ethylhexyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyltoluene, α)
-Methylstyrene etc.), vinyl ethers (methyl vinyl ether etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate etc.), acrylamides (N-tert-butyl acrylamide, N-cyclohexyl acrylamide etc.), methacrylamide Examples thereof include acrylonitrile derivative and the like.

The fluorine-containing resin used for the low refractive index layer preferably has an average particle size of 0.1 μm in order to impart scratch resistance.
m or less, more preferably 0.001 to 0.05 μm S
It is preferable to use ultrafine oxide particles of i. From the viewpoint of antireflection property, the lower the refractive index, the more preferable, but as the refractive index of the fluororesin is lowered, the scratch resistance deteriorates.
Therefore, by optimizing the refractive index of the fluorine-containing resin and the addition amount of the Si oxide ultrafine particles, it is possible to find the best balance between scratch resistance and low refractive index. As the Si oxide ultrafine particles, silica sol dispersed in a commercially available organic solvent may be added to the coating solution as it is, or various commercially available silica powders may be dispersed in an organic solvent and used.

The light-scattering film of the present invention has a vertical peel charge of -200 pc (pico coulomb) / cm ² measured at room temperature and normal humidity for either triacetyl cellulose (TAC) or polyethylene terephthalate (PET).
It is preferably +200 pc (pico coulomb) / cm ² . More preferably -100 pc / cm to +10
0 pc / cm ² , more preferably -50 pc /
cm ² to +50 pc / cm ² , most preferably 0 p
It is c / cm ² . Here, the unit pc (pico coulomb) is 10 ⁻¹² coulomb. More preferably,
Vertical peel charge measured at room temperature 10% RH is -100 pc.
/ Cm ² to +100 pc / cm ² , more preferably −50 pc / cm ² to +50 pc / cm ² , and most preferably 0 pc / cm ² .

The method of measuring the vertical peeling charge is as follows. The measurement sample is left in advance for 2 hours or more under the environment of measurement temperature and humidity. The measuring device is composed of a table on which the sample to be measured is placed and a head which holds the film of the other party and which can repeatedly press and peel from the sample to be measured, and an electrometer for measuring the charge amount is connected to this head. The antiglare light-scattering film to be measured is placed on a table, and TAC or PET is attached to the head. After destaticizing the measurement portion, the head is pressed against the measurement sample and peeling is repeated, and the charge values at the first peeling and the fifth peeling are read and averaged. This is repeated for 3 samples with different samples, and the average of all is taken as the vertical peeling charge.

Depending on the type of the companion film or the sample to be measured, it may be positively charged or negatively charged, but the problem is the magnitude of the absolute value. Further, generally, the absolute value of charging becomes larger in an environment of low humidity. The absolute value of the antiglare light scattering film of the present invention is also small.

The light-scattering film of the present invention is excellent in dustproofness because the absolute value of vertical peeling charge at room temperature and normal humidity and room temperature 10% RH is small. The value of the vertical peeling charge is set within the above range by adjusting the ratio of various elements on the surface of the light-scattering film.

The surface resistance value of the light-scattering film of the present invention is
It is 1 × 10 ¹¹ Ω / □ or more, preferably 1 × 10 ¹² Ω / □ or more. The method for measuring the surface resistance value is the circular electrode method described in JIS. That is, the current value one minute after the voltage application is read to obtain the surface resistance value (SR). In the present invention,
Reduce the surface resistance value, for example 1 × 10 ¹⁰ Ω / □
The idea is fundamentally different from the method of improving the dustproof property (dust adhesion preventive property) by making the following. This method is not used because the image display quality is deteriorated. In the present invention, the absolute value of vertical peeling electrification is made small by the above-mentioned method. Therefore, it is not necessary to make the surface resistance value small, and the surface resistance value is 1 × 10. ¹¹ Ω
/ It can be set to □ or more and the image display quality does not deteriorate.

In the light-scattering film of the present invention, the average value of the specular reflectance at the incidence of 5 degrees in the wavelength region of 450 nm to 650 nm is 2.5% or less, preferably 1.2% or less, and more preferably. It is 1.1% or less. Also,
Integrated reflectance at 5 degree incidence from 450 nm to 650 n
The average value in the wavelength region up to m is preferably 2.5% or less, and more preferably 2.3% or less.

The specular reflectance at 5 degrees incidence and the incidence at 5 degrees will be described. The specular reflectance at 5 ° incidence is the ratio of the intensity of light reflected at −5 ° in the normal direction to the light incident at + 5 ° in the normal direction of the sample, and is a measure of the reflection of the background due to specular reflection. When applied to an antiglare light-scattering film, the intensity of light reflected at −5 degrees in the normal direction is weakened by the amount of scattered light caused by surface irregularities provided for imparting antiglare properties. Therefore, it can be said that the specular reflectance is a measurement method that reflects the contributions of both the antiglare property and the antireflection property.

On the other hand, the integrated reflectance at 5 degrees incidence is
It is the ratio of the integrated value of the intensity of light reflected in all directions to the light incident from the sample normal direction +5 degrees. When applied to a light-scattering film, since the reduction of reflected light due to antiglare property does not occur, it is possible to measure only the antireflection property. Therefore, both the above reflectances of 450n
By setting the average values in the wavelength range from m to 650 nm to 2.5% or less (specular reflectance) and 2.5% or less (integrated reflectance), the antiglare property and the antireflection property are simultaneously satisfied. It will be possible.

When the average value of the specular reflectance of the light-scattering film at 5 degrees incidence in the wavelength region from 450 nm to 650 nm exceeds 2.5%, the reflection of the background becomes a concern, and the surface film of the display device is annoyed. The visibility when applied is reduced. On the other hand, if the average value of the integrated reflectance of the light-scattering film at 5 degrees incidence in the wavelength region from 450 nm to 650 nm exceeds 2.5%, the contrast improving effect of the display device is reduced and the antiglare property is imparted. The display screen becomes white due to the scattered light due to the surface irregularities, and the display quality of the display device deteriorates.

In the light-scattering film of the present invention, the tint of specular reflection light with respect to the 5 degree incident light of the CIE standard light source D65 is CI.
E1976 When L * a * b * color space L *, a *, and b * values are quantified, L * ≦ 10 and 0 ≦ a * ≦, respectively.
2, it is preferable to be designed so as to fall within the range of −5 ≦ b * ≦ 2. The tint of regular reflection light that satisfies this is a neutral tint. The tint of specular reflection light with respect to the 5 degree incident light of the CIE standard light source D65 is calculated by calculating the product of the actual measurement value of the specular reflectance in the wavelength range of 380 nm to 780 nm and the spectral distribution of the light source D65 at each wavelength. From the obtained spectral reflection spectrum, CIE197
It can be quantified by calculating the L * value, the a * value, and the b * value of the 6L * a * b * color space. When the L * value is larger than 10, the antireflection property is not sufficient. If the a * value is larger than 2, the reddish purple color of the reflected light is strong, and if it is less than 0, the green color is strong, which is not preferable. Also, the b * value is −
When it is less than 5, the bluish tint is strong, and when it is more than 2, the yellowish tint is strong, which is not preferable.

The light-scattering film having such a neutral color of reflected light and having a low reflectance optimizes the balance between the refractive index of the low refractive index layer and the refractive index of the binder material of the antiglare layer. It is obtained by doing. In general, an antireflection film composed of three or more layers of optical thin film formed by vapor deposition, sputtering or the like can reduce the average value of the specular reflectance to 0.3% or less, and thus the L * value to 3 or less. Was 10 or more and the b * value was less than -10, and the tint of the reflected light was very strong. However, in the antiglare light-scattering film of the present invention, in terms of the tint of the reflected light. Has been greatly improved.

<Transparent Substrate> Materials for the transparent substrate include a transparent resin film, a transparent resin plate, a transparent resin sheet and transparent glass. As the transparent resin film, triacetyl cellulose (TAC) film (refractive index 1.48), polyethylene terephthalate (PET) film, diacetylene cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film Polyurethane resin film, polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyetherketone film, (meth) acrylonitrile film, etc. can be used. The thickness is usually about 25 μm to 1000 μm. Since the transparent substrate of the present invention is used on the outermost surface of a polarizing plate, it is preferable to use a cellulose acetate film which is generally used as a protective film for polarizing plates. Hereinafter, a cellulose acetate film having high transparency and a smooth surface, which can be particularly preferably used for the transparent base film of the light-scattering film of the present invention, will be described.

<High transparency and high smoothness cellulose acetate film> In the present invention, the degree of acetylation is 59.0 to 61.5.
It is preferred to use cellulose acetate which is%. The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation is ASTM: D-817-91.
According to the measurement and calculation of the acetylation degree in (Test method for cellulose acetate, etc.). The viscosity average degree of polymerization (DP) of the cellulose ester is preferably 250 or more, more preferably 290 or more. Also,
The cellulose ester used in the present invention preferably has a narrow molecular weight distribution of Mw / Mn (Mw is a mass average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mw / Mn is preferably 1.0 to 1.7, more preferably 1.3 to 1.65, and most preferably 1.4 to 1.6. preferable.

Generally, cellulose acylate of 2, 3,
The 6-hydroxyl group is not evenly distributed in 1/3 of the entire substitution degree, and the 6-hydroxyl group substitution degree tends to be small. In the present invention, it is preferable that the substitution degree of the 6-position hydroxyl group of cellulose acylate is higher than that of the 2- and 3-position.
The hydroxyl group at the 6-position is preferably substituted by 32% or more with an acyl group, more preferably 33% or more, and particularly preferably 34% or more with respect to the entire substitution degree. Further, the substitution degree of the 6-position acyl group of cellulose acylate is preferably 0.88 or more. The 6-position hydroxyl group may be substituted with an acyl group having 3 or more carbon atoms, such as a propionyl group, a butyroyl group, a valeroyl group, a benzoyl group, and an acryloyl group, in addition to the acetyl group. The substitution degree at each position can be measured by NMR. As the cellulose acylate of the present invention, “0043” to “0044” “Example” [Synthesis Example 1] described in JP-A-11-5851,
"0048" to "0049" [Synthesis example 2], "005"
The cellulose acetate obtained by the method of 1 "-" 0052 "[Synthesis example 3] can be used.

[Production of Cellulose Acetate Film]
It is preferable to produce the cellulose acetate film by the solvent casting method. In the solvent cast method, a film is manufactured using a solution (dope) in which cellulose acetate is dissolved in an organic solvent. The organic solvent is
It contains a solvent selected from ether having 3 to 12 carbon atoms, ketone having 3 to 12 carbon atoms, ester having 3 to 12 carbon atoms, and halogenated hydrocarbon having 1 to 6 carbon atoms. preferable. The ether, ketone and ester may have a cyclic structure. Functional groups of ethers, ketones and esters (ie -O
A compound having two or more of any one of —, —CO— and —COO—) can also be used as the organic solvent.
The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. Examples of the ester having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.

Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The number of carbon atoms in the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine.
The proportion of hydrogen atoms in the halogenated hydrocarbon substituted with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and 3
It is more preferably 5 to 65 mol%, and most preferably 40 to 60 mol%. Methylene chloride is a typical halogenated hydrocarbon. You may mix and use 2 or more types of organic solvents.

The cellulose acetate solution can be prepared by a general method. The general method means treatment at a temperature of 0 ° C. or higher (normal temperature or high temperature). The solution can be prepared by using the dope preparation method and apparatus in the usual solvent casting method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent. A non-chlorine-based solvent can also be used, and examples thereof include those described in Published Technical Report 2001-1745. The amount of cellulose acetate is adjusted so that the obtained solution contains 10 to 40% by mass. The amount of cellulose acetate is more preferably 10 to 30% by mass. The organic solvent (main solvent) may contain any of the additives described below. The solution is
It can be prepared by stirring cellulose acetate and an organic solvent at room temperature (0 to 40 ° C.). The highly concentrated solution may be stirred under pressure and heat.
Specifically, the cellulose acetate and the organic solvent are placed in a pressure vessel and sealed, and the mixture is stirred under pressure while being heated to a temperature not lower than the boiling point of the solvent at room temperature and not boiling the solvent. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., and more preferably 80.
To 110 ° C.

The respective components may be roughly mixed in advance and then placed in a container. Moreover, you may throw in in a container one by one. The container must be configured to allow stirring. The container can be pressurized by injecting an inert gas such as nitrogen gas. Alternatively, the increase in vapor pressure of the solvent due to heating may be used.
Alternatively, after sealing the container, each component may be added under pressure. When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. It is also possible to heat the entire container by providing a plate heater outside the container and piping to circulate the liquid. It is preferable to provide a stirring blade inside the container and use this to stir. The stirring blade is preferably long enough to reach the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the wall of the container. Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in a container.
The prepared dope is cooled and then taken out from the container, or after taking out, it is cooled using a heat exchanger or the like.

The solution can be prepared by the cooling dissolution method. In the cooling dissolution method, cellulose acetate can be dissolved even in an organic solvent which is difficult to dissolve by a usual dissolution method. Even if the solvent is a solvent that can dissolve cellulose acetate by an ordinary dissolution method, the cooling dissolution method has an effect of rapidly obtaining a uniform solution. In the cooling dissolution method, first, cellulose acetate is gradually added to an organic solvent with stirring at room temperature. The amount of cellulose acetate is preferably adjusted so as to be contained in this mixture in an amount of 10 to 40% by mass. The amount of cellulose acetate is more preferably 10 to 30% by mass. Furthermore, any additives described below may be added to the mixture.

Then, the mixture is heated to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50).
To -20 ° C, most preferably -50 to -30 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (-75 ° C) or a cooled diethylene glycol solution (-30 to -20 ° C). When cooled in this way, the mixture of cellulose acetate and organic solvent solidifies. The cooling rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, 12
Most preferably, it is at least ° C / min. The higher the cooling rate, the more preferable, but 10000 ° C./sec is the theoretical upper limit, 1000 ° C./sec is the technical upper limit, and 1
00 ° C./sec is a practical upper limit. The cooling rate is
The difference between the temperature at the start of cooling and the final cooling temperature is
It is the value divided by the time from the start of cooling until the final cooling temperature is reached.

Further, this is 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C.,
When heated to the most preferably 0 to 50 ° C., the cellulose acetate dissolves in the organic solvent. The temperature may be raised by leaving it at room temperature or by heating it in a warm bath. The heating rate is preferably 4 ° C / min or more, and 8 ° C / min.
It is more preferably at least minutes, and most preferably at 12 ° C./minute or more. The higher the heating rate, the more preferable, but 10000 ° C./sec is the theoretical upper limit,
0 ° C./sec is the technical upper limit and 100 ° C./sec is the practical upper limit. The heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating to the final heating temperature. . A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be judged only by visually observing the appearance of the solution.

In the cooling dissolution method, it is desirable to use a closed container in order to avoid mixing of water due to dew condensation during cooling. In the cooling and heating operation, pressure is applied during cooling,
If the pressure is reduced during heating, the dissolution time can be shortened. In order to carry out the pressurization and depressurization, it is desirable to use a pressure resistant container. A 20% by mass solution of cellulose acetate (acetylation degree: 60.9%, viscosity average degree of polymerization: 299) dissolved in methyl acetate by a cooling dissolution method was 3% by differential scanning calorimetry (DSC).
A quasi-phase transition point between a sol state and a gel state exists near 3 ° C., and at this temperature or lower, a uniform gel state is obtained. Therefore,
This solution must be kept at a temperature not lower than the pseudo phase transition temperature, preferably about 10 ° C. plus the gel phase transition temperature. However, this pseudo-phase transition temperature differs depending on the degree of acetylation of cellulose acetate, the viscosity average degree of polymerization, the solution concentration and the organic solvent used.

A cellulose acetate film is produced from the prepared cellulose acetate solution (dope) by the solvent casting method. The dope is cast on a drum or band and the solvent is evaporated to form a film. The dope before casting is preferably adjusted in concentration so that the solid content is 18 to 35%. The surface of the drum or band is preferably mirror-finished. Regarding the casting and drying methods in the solvent casting method, US Pat.
No. 03, No. 2492078, No. 2492977, No. 2492978, No. 2607704, No. 27390.
No. 69, No. 2739070, British Patent 640731.
Nos. 736,892 and JP-B-45-455
4, JP-A-49-5614, JP-A-60-176834.
Nos. 60-203430 and 62-115035. The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or lower.
After casting, it is preferable to apply air for 2 seconds or more to dry. It is also possible to strip the obtained film from the drum or band and further dry it with hot air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, the time from casting to stripping can be shortened. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

The prepared cellulose acylate solution (dope) may be used to form a film by casting two or more layers. In this case, it is preferable to produce the cellulose acylate film by the solvent casting method. The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 10 to 40%. The surface of the drum or band is preferably mirror-finished.

When a plurality of cellulose acylate solutions having two or more layers are cast, a plurality of cellulose acylate solutions can be cast, and a plurality of casts provided at intervals in the traveling direction of the support. A film may be produced by casting a solution containing cellulose acylate from the mouth and laminating the solutions, and for example, JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285,
The method described in etc. can be applied. Further, it may be formed into a film by casting a cellulose acylate solution from two casting ports, for example, JP-B-60-27.
562, JP-A-61-94724, JP-A-61-9
47245, JP 61-104813 A, JP 6
It can be carried out by the method described in JP-A-1-158413 and JP-A-6-134933. Also, JP-A-56-16261
A cellulose acylate film casting method in which the flow of the high-viscosity cellulose acylate solution described in No. 7 is wrapped with a low-viscosity cellulose acylate solution and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded may be used.

Alternatively, by using two casting ports, the film formed on the support by the first casting port is peeled off, and the second casting is performed on the side in contact with the support surface. , A film may be prepared, for example, Japanese Patent Publication No.
4-20235. The cellulose acylate solution to be cast may be the same solution,
Different cellulose acylate solutions may be used and are not particularly limited. In order to impart a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Further, the cellulose acylate solution is used for other functional layers (for example, an adhesive layer,
A dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing film, etc.) can be simultaneously cast.

In the case of a monolayer solution, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution in order to obtain a required film thickness. In this case, the stability of the cellulose acylate solution is poor and the cellulose acylate solution is solid. This often causes problems, such as the generation of objects, defective spots, and poor flatness. As a solution to this problem, by casting a plurality of cellulose acylate solutions through a casting port, it is possible to simultaneously extrude a highly viscous solution onto a support, thereby improving the flatness and producing an excellent planar film. Not only that, but also by using a concentrated cellulose acylate solution, the reduction of the drying load can be achieved, and the film production speed can be increased.

A plasticizer may be added to the cellulose acetate film in order to improve the mechanical properties or improve the drying speed. As a plasticizer,
Phosphate esters or carboxylic acid esters are used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TC).
P) is included. Typical carboxylic acid esters are phthalic acid esters and citric acid esters. Examples of phthalates include dimethyl phthalate (DM
P), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). An example of a citric acid ester is triethyl O-acetylcitrate (OACT).
E) and O-acetyl tributyl citrate (OACT
B) is included. Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate,
Includes dibutyl sebacate and various trimellitic acid esters. Phthalates plasticizer (DMP, DE
P, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred. The amount of plasticizer added is 0.1 to 25 times the amount of cellulose ester.
It is preferably mass%, more preferably 1 to 20 mass%, and most preferably 3 to 15 mass%.

A deterioration inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the cellulose acetate film. For the deterioration preventing agent, see JP-A-3-19920.
No. 1, No. 5-1907073, No. 5-194789
Nos. 5,271,471 and 6,107,854. The addition amount of the deterioration inhibitor is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. If the addition amount is less than 0.01% by mass, the effect of the deterioration inhibitor is hardly recognized. Addition amount is 1% by mass
If it exceeds the range, bleed-out (bleeding) of the deterioration preventive agent on the film surface may be observed. Butylated hydroxytoluene (BHT) and tribenzylamine (TBA) can be mentioned as examples of particularly preferable deterioration preventing agents.

[Surface Treatment of Cellulose Acetate Film] The cellulose acetate film is preferably surface-treated. Specific methods include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment and ultraviolet irradiation treatment. In addition, JP-A-7-
It is also preferred to provide an undercoat layer as described in the specification of 333433. From the viewpoint of maintaining the flatness of the film, the temperature of the cellulose acetate film in these treatments is preferably Tg or lower, specifically 150 ° C. or lower. When used as a transparent protective film for a polarizing plate, it is particularly preferable to carry out acid treatment or alkali treatment, that is, saponification treatment of cellulose acetate, from the viewpoint of adhesion to the polarizing film. The surface energy is preferably 55 mN / m or more, 60 m
More preferably, it is N / m or more and 75 mN / m or less.

The alkali saponification treatment will be specifically described below as an example. After immersing the film surface in an alkaline solution,
It is preferable to carry out a cycle of neutralizing with an acidic solution, washing with water and drying. Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution, and the normal concentration of hydroxide ion is preferably 0.1N to 3.0N, more preferably 0.5N to 2.0N. preferable. The temperature of the alkaline solution is preferably room temperature to 90 ° C, more preferably 40 ° C to 70 ° C. From the viewpoint of productivity, it is preferable to apply an alkaline solution, and after the saponification treatment, remove the alkali from the film surface by washing with water. From the viewpoint of wettability, alcohols such as IPA, n-butanol, methanol and ethanol are preferable as the coating solvent, and it is preferable to add water, propylene glycol, ethylene glycol and the like as an alkali dissolution aid. The surface energy of a solid can be determined by the contact angle method, the heat of wetting method, and the adsorption method as described in "Wet Basics and Applications" (published by Realize 1989.12.10). In the case of the cellulose acetate film of the present invention, it is preferable to use the contact angle method. Specifically, two kinds of solutions having known surface energies are dropped onto a cellulose acetate film, and at the intersection between the surface of the droplet and the film surface, the angle between the tangent line drawn to the droplet and the film surface is used. The angle containing the drop is defined as the contact angle,
The surface energy of the film can be calculated by calculation.

<Optically Anisotropic Layer Comprising Liquid Crystal Compound> [Liquid Crystalline Compound] The liquid crystal compound used in the present invention may be a rod-shaped liquid crystal or a discotic liquid crystal, and they may be a high-molecular liquid crystal or a low-molecular liquid crystal, Further, it also includes those in which a low-molecular liquid crystal is crosslinked and no longer exhibits liquid crystallinity. The most preferable liquid crystal compound of the present invention is discotic liquid crystal.

As a preferable example of the rod-shaped liquid crystal, Japanese Patent Application Laid-Open No. 20
Examples thereof include those described in 00-304932.
Examples of the discotic liquid crystal of the present invention include C.I. De
Strade et al., Mol. Cryst. 71
Vol., Page 111 (1981), benzene derivatives, C.I. Report of Destrade et al., Mol.
Cryst. 122, 141 (1985), Ph
ysics lett, A, 78, 82 (199
0)), a truxene derivative described in B. Kohn
e et al., Angew. Chem. Volume 96, 70
Page (1984) and the cyclohexane derivative described in J. M. Lehn et al., J. Chem. Co
mmun. , Pp. 1794 (1985), J. Zhan
g., et al. Am. Chem. Soc. 116
Vol. 2, pp. 2655 (1994), and azacrown-based and phenylacetylene-based macrocycles. Generally, the discotic liquid crystal has a structure in which a linear alkyl group, an alkoxy group, a substituted benzoyloxy group or the like is linearly substituted as a straight chain with these as a mother nucleus of the molecular center, and liquid crystallinity is improved. Show. However, the molecule is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. Further, in the present invention, the formation of a discotic compound does not necessarily mean that the final product is the compound, and for example, the low molecular weight discotic liquid crystal is heated,
Those having a group which reacts with light or the like and consequently polymerized or crosslinked by reaction with heat, light or the like to have a high molecular weight and lose liquid crystallinity are also included. A preferred example of the discotic liquid crystal is described in JP-A-8-50206.

The optically anisotropic layer of the present invention is a layer having a negative birefringence composed of a compound having a discotic structural unit, and the surface of the discotic structural unit is tilted with respect to the transparent support surface, and The angle formed by the surface of the discotic structural unit and the surface of the transparent support preferably changes in the depth direction of the optically anisotropic layer.

The surface angle (tilt angle) of the discotic structural unit generally increases or decreases in the depth direction of the optically anisotropic layer and as the distance from the bottom surface of the optically anisotropic layer increases. The tilt angle preferably increases with increasing distance. Further, examples of the change in the tilt angle include continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and decrease, and intermittent change including increase and decrease. it can. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. It is preferable that the inclination angle is increased or decreased as a whole even if it includes a region that does not change. Further, it is preferable that the inclination angle is increased as a whole, and it is particularly preferable that the inclination angle is continuously changed.

The above-mentioned optically anisotropic layer is generally formed by applying a solution of a discotic compound and another compound dissolved in a solvent onto the alignment film, drying the solution, and then heating it to a discotic nematic phase forming temperature, and then adjusting the alignment state ( It is obtained by maintaining and cooling the discotic nematic phase). Alternatively, the optically anisotropic layer may be prepared by applying a solution of a discotic compound and another compound (further, for example, a polymerizable monomer or a photopolymerization initiator) dissolved in a solvent onto the alignment film, followed by drying, and then discotic nematic. It is obtained by heating to a phase forming temperature, polymerizing (by irradiation with UV light, etc.), and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is 70 to
300 degreeC is preferable and 70-170 degreeC is especially preferable.

For example, the tilt angle of the discotic unit on the support side can be adjusted by generally selecting the discotic compound or the material of the alignment film, or by selecting the rubbing treatment method. Further, the inclination angle of the discotic unit on the surface side (air side) is generally selected from a discotic compound or another compound (eg, a plasticizer, a surfactant, a polymerizable monomer and a polymer) used together with the discotic compound. It can be adjusted. Further, the degree of change in the tilt angle can be adjusted by the above selection.

The above-mentioned plasticizer, surfactant and polymerizable monomer have compatibility with the discotic compound,
Any compound can be used as long as it can change the tilt angle of the liquid crystal discotic compound or does not hinder the alignment. Of these, polymerizable monomers (eg, compounds having a vinyl group, a vinyloxy group, an acryloyl group and a methacryloyl group) are preferable.
The above compound is generally used in an amount of 1 to 50% by mass (preferably 5 to 30% by mass) based on the discotic compound. Further, examples of preferable polymerizable monomers include polyfunctional acrylates. The number of functional groups is 3
It is preferably functional or higher, and more preferably tetrafunctional or higher. Most preferred are hexafunctional monomers. Preferred examples of the hexafunctional monomer include dipentaerythritol hexaacrylate. It is also possible to mix and use these polyfunctional monomers having different numbers of functional groups.

As the above-mentioned polymer, any polymer can be used as long as it is compatible with the discotic compound and can change the tilt angle of the liquid crystalline discotic compound. Cellulose ester can be mentioned as an example of a polymer. Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose and cellulose acetate butyrate. The polymer is generally 0.1 to 10% by mass (preferably 0.1 to 8% by mass, particularly 0.1 to 5% by mass) relative to the discotic compound so as not to hinder the alignment of the liquid crystalline discotic compound. ) Amount used. In the present invention, the cellulose acetate film, the alignment film provided thereon, and the discotic liquid crystal formed on the alignment film are preferably rubbing-treated films made of a crosslinked polymer.

[Alignment Film] The alignment film of the present invention has a crosslinked structure of 2
It is a layer composed of a seed polymer. It is possible to use any polymer which is crosslinkable with a crosslinking agent, even if at least one polymer is itself crosslinkable. The above-mentioned alignment film is formed by reacting a polymer having a functional group or a polymer having a functional group introduced therein with light, heat, a change in PH, etc. between the polymers; It can be formed by introducing a bonding group derived from a cross-linking agent between polymers using an agent and cross-linking between the polymers.

Such cross-linking is usually carried out by applying a coating solution containing the above-mentioned polymer or a mixture of the polymer and a cross-linking agent on a transparent support and then heating the solution. Since it suffices to ensure the durability, the treatment for crosslinking may be carried out at any stage after the alignment film is applied on the transparent support until the final optical compensation sheet is obtained. Considering the orientation of the compound having a discotic structure (optically anisotropic layer) formed on the orientation film, it is also preferable that the compound having the discotic structure is oriented and then sufficiently crosslinked. That is, on the transparent support,
When a coating solution containing a polymer and a cross-linking agent capable of crosslinking the polymer is applied, it is dried by heating (generally, crosslinking is carried out, but when the heating temperature is low, it was heated to the discotic nematic phase formation temperature. (Cross-linking sometimes progresses further), rubbing treatment is performed to form an alignment film,
Then, a coating solution containing a compound having a disc-shaped structural unit is applied onto the alignment film, heated to a discotic nematic phase formation temperature or higher, and then cooled to form an optically anisotropic layer.

The polymer used in the alignment film of the present invention is
Either polymers which are themselves crosslinkable or polymers which are crosslinked by crosslinking agents can be used. Of course, some polymers are capable of both. Examples of the above polymer include polymethylmethacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleinimide copolymer, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyltoluene copolymer. , Chlorosulfonated polyethylene,
Polymers such as nitrocellulose, polyvinyl chloride, chlorinated polyolefins, polyesters, polyimides, vinyl acetate / vinyl chloride copolymers, ethylene / vinyl acetate copolymers, carboxymethyl cellulose, polyethylene, polypropylene and polycarbonate, and silane coupling agents, etc. A compound can be mentioned. Examples of preferable polymers are water-soluble polymers such as poly (N-methylol acrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol, and further gelatin, polyvinyl alcohol and modified polyvinyl alcohol are preferable, and especially polyvinyl alcohol is preferable. Bill alcohol and modified polyvinyl alcohol can be mentioned.

Among the above polymers, polyvinyl alcohol or modified polyvinyl alcohol is preferable, and it is most preferable to use two kinds of polyvinyl alcohol or modified polyvinyl alcohol having different polymerization degrees in combination. The polyvinyl alcohol has, for example, a saponification degree of 70 to 100%, and generally has a saponification degree of 80 to 100%.
More preferably, the saponification degree is 85 to 95%. The degree of polymerization is preferably in the range of 100 to 3000.
As the modified polyvinyl alcohol, one modified by copolymerization (as the modifying group, for example, COONa, Si (OX))
₃ , N (CH ₃ ) ₃ · Cl, C ₉ H ₁₉ COO, SO ₃ N
a, C ₁₂ H _25, etc.), those modified by chain transfer (eg, COONa, SH, C
₁₂ H ₂₅ etc.), those modified by block polymerization (eg, COOH, CON
H ₂ , COOR, C ₆ H _{5 and the} like are introduced), and modified products of polyvinyl alcohol. Among these, unmodified or modified polyvinyl alcohol having a saponification degree of 80 to 100%, and more preferably unmodified or alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95%. The method of synthesizing these modified polymers, the measurement of visible absorption spectrum, and the method of determining the introduction rate y are described in detail in JP-A-8-338913.

The following may be mentioned as specific examples of the cross-linking agent used together with the above-mentioned polymers such as polyvinyl alcohol. These are water-soluble polymers, especially polyvinyl alcohol and modified polyvinyl alcohol (the above-mentioned specific modified products Is also included). For example, activating aldehydes (eg, formaldehyde, glyoxal and glutaraldehyde), N-methylol compounds (eg, dimethylolurea and methyloldimethylhydantoin), dioxane derivatives (eg, 2,3-dihydroxydioxane), and carboxyl groups. Compounds that act by (eg, carbenium, 2-naphthalene sulfonate, 1,1-bispyrrolidino-1-
Chloropyridinium and 1-morpholinocarbonyl-3
-(Sulfonatoaminomethyl)), an active vinyl compound (eg 1,3,5-triacroyl-hexahydro-s)
-Triazine, bis (vinyl sulfone) methane and N,
N′-methylenebis- [β- (vinylsulfonyl) propionamide]), active halogen compound (eg, 2,4-
Dichloro-6-hydroxy-S-triazine), isoxazoles, dialdehyde starch, and the like. These can be used alone or in combination. In view of productivity, it is preferable to use aldehydes having high reaction activity, especially glutaraldehyde.

The cross-linking agent is not particularly limited, and the addition amount tends to be improved as the addition amount increases with respect to the moisture resistance. However, since the alignment ability as an alignment film decreases when 50% by mass or more is added to the polymer,
0.1 to 20 mass% is preferable, and 0.5 to 15 mass% is particularly preferable. The alignment film of the present invention contains some cross-linking agent that has not reacted even after the completion of the cross-linking reaction, but the amount of the cross-linking agent is preferably 1.0% by mass or less in the alignment film. It is particularly preferably 0.5% by mass or less. If the cross-linking agent is contained in the alignment film in an amount exceeding 1.0 mass, sufficient durability cannot be obtained. That is,
When used in a liquid crystal display device, reticulation may occur when it is used for a long period of time or left in a high temperature and high humidity atmosphere for a long period of time.

The alignment film of the present invention is basically prepared by applying it on a transparent support containing the above-mentioned polymer and a cross-linking agent, which is a material for forming an alignment film, followed by heat-drying (cross-linking) and rubbing treatment. It can be formed, and the crosslinking reaction may be carried out at any time after coating on the transparent support, as described above. When using a water-soluble polymer such as the polyvinyl alcohol as an alignment film forming material, the coating liquid is preferably a mixed solvent of an organic solvent such as methanol and a water having an antifoaming action, and the ratio is mass. The ratio of water: methanol is generally 0: 100 to 99: 1, preferably 0: 100 to 91: 9. Thereby, the generation of bubbles is suppressed, and the defects on the alignment film and, further, on the surface of the optically anisotropic layer are significantly reduced. As a coating method, a spin coating method, a dip coating method,
The curtain coating method, the extrusion coating method, the bar coating method and the E-type coating method can be mentioned. The E-type coating method is particularly preferable. The film thickness is preferably 0.1 to 10 μm. The heat drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, the temperature is preferably 60 ° C to 100 ° C, particularly 80 ° C to
100 ° C. is preferred. The drying time can be 1 minute to 36 hours. It is preferably 5 minutes to 30 minutes. The pH is also preferably set to an optimum value for the crosslinking agent used, and when glutaraldehyde is used, p
H4.5-5.5, 5 are especially preferable.

The alignment film is provided on the transparent support or on the above-mentioned undercoat layer. The alignment film can be obtained by crosslinking the polymer layer as described above and then rubbing the surface. The alignment film functions so as to define the alignment direction of the liquid crystal discotic compound provided thereon.

For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process for LCD can be used. That is, a method of obtaining orientation by rubbing the surface of the orientation film in a certain direction with paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times with a cloth or the like in which fibers having uniform length and thickness are evenly flocked.

<Transparent Support Coated with Optically Anisotropic Layer Made of Liquid Crystal Compound> The transparent support is not particularly limited as long as it is a plastic film having a high transmittance, but it is a protective film of a polarizing plate such as cellulose. Preference is given to using acetate. It may be optically uniaxial or biaxial.
The transparent support on which the optically anisotropic layer is coated plays an optically important role in itself, and therefore R of the transparent support of the present invention is used.
It is preferable that the e retardation value is 0 to 200 nm and the Rth retardation value is adjusted to 70 to 400 nm. When two optically anisotropic cellulose acetate films are used in a liquid crystal display device, the Rth retardation value of the film is 70 to 250 nm.
Is preferred. When a single optically anisotropic cellulose acetate film is used in a liquid crystal display device, the Rth retardation value of the film is 150 to 400 n.
It is preferably m.

The birefringence index (Δn: nx-ny) of the cellulose acetate film is 0.00 to 0.00.
It is preferably 2. The birefringence of the cellulose acetate film in the thickness direction {(nx + ny) / 2-
nz} is preferably 0.001 to 0.04. The retardation value (Re) is calculated according to the following formula. Retardation value (Re) = (nx−ny) × d, where nx is the in-plane refractive index in the slow axis direction (maximum in-plane refractive index) of the retardation plate; ny is the retardation It is the refractive index in the direction perpendicular to the slow axis in the plane of the plate. (II) Rth = {(nx + ny) / 2−nz} × d In the formula (II), the refractive index in the slow axis direction (direction in which the refractive index is maximum) in the film plane is shown. ny is the refractive index in the fast axis direction (direction in which the refractive index is minimum) in the film plane. nz is a refractive index in the thickness direction of the film. d
Is the film thickness in nm.

[Polarizing Plate] The polarizing plate comprises a polarizing film and two protective films disposed on both sides of the polarizing film. The light-scattering film of the present invention can be used as one of the protective films. As the other protective film, a usual cellulose acetate film may be used. The polarizing film includes an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, and a polyene-based polarizing film. The iodine type polarizing film and the dye type polarizing film are generally manufactured using a polyvinyl alcohol type film. The transparent substrate of the light-scattering film and the slow axis of the cellulose acetate film and the transmission axis of the polarizing film are arranged so as to be substantially parallel to each other. It was found that the moisture permeability of the protective film is important for the productivity of the polarizing plate. The polarizing film and the protective film are attached with an aqueous adhesive,
This adhesive solvent is dried by diffusing through the protective film. The higher the moisture permeability of the protective film, the faster the drying will be and the more the productivity will improve. The polarization ability is reduced.

The moisture permeability of the polarizing plate is determined by the thickness of the transparent substrate, the polymer film (and the polymerizable liquid crystal compound), the free volume,
Determined by hydrophilicity / hydrophobicity and the like. When the light-scattering film of the present invention is used as a protective film for a polarizing plate, it has a moisture permeability of 1
It is preferably from 00 to 1000 g / m2 · 24 hrs and 3
More preferably, it is from 00 to 700 g / m2 · 24 hrs.
In the case of film formation, the thickness of the transparent substrate can be adjusted by the lip flow rate and line speed, or stretching and compression. Since the moisture permeability differs depending on the main material used, it is possible to adjust the thickness to a preferable range. In the case of film formation, the free volume of the transparent substrate can be adjusted by the drying temperature and time. Also in this case, since the moisture permeability differs depending on the main material used, it is possible to adjust the free volume to a preferable range. The hydrophilicity / hydrophobicity of the transparent substrate can be adjusted by an additive. By adding a hydrophilic additive in the free volume, the moisture permeability becomes high,
On the contrary, moisture permeability can be lowered by adding a hydrophobic additive. By independently controlling the moisture permeability,
A polarizing plate having an optical compensation ability can be manufactured at low cost and with high productivity.

In the present invention, the light-scattering film of the present invention or a polarizing plate in which the light-scattering film, a polarizing film and an optically anisotropic layer comprising a liquid crystalline compound are laminated in this order is preferable.
The optically anisotropic layer may be formed as a layer containing a discotic compound (discotic compound) or a rod-shaped liquid crystal compound on the polymer film. In the present invention, the liquid crystal compound is preferably a discotic compound. The optically anisotropic layer is preferably formed by orienting a discotic compound (or a rod-shaped liquid crystal compound) and fixing the orientation state. Discotic compounds generally have a large birefringence. In addition, the discotic compound has various orientation forms. Therefore, by using the discotic compound, an optically anisotropic layer having optical properties which cannot be obtained by the conventional stretched birefringent film can be obtained. Regarding the optically anisotropic layer using a discotic compound, JP-A-6-214116 and U.S. Pat. No. 5,583,679.
No. 5,646,703, West German Patent Publication 3911620.
There is a description in each specification of A1.

[Liquid Crystal Display Device] The light-scattering film or polarizing plate of the present invention is advantageously used in a liquid crystal display device,
It is preferably used for the outermost layer of the display. TN,
The liquid crystal display device of ECB, MVA, IPS and OCB mode is composed of a liquid crystal cell and two polarizing plates arranged on both sides thereof. The liquid crystal cell carries liquid crystal between two electrode substrates. In the liquid crystal display device, one optically anisotropic layer is arranged between the liquid crystal cell and one of the polarizing plates, or two optically anisotropic layers are arranged between the liquid crystal cell and both of the polarizing plates. Liquid crystal cells are VA mode, OCB mode, EC
The B mode or the TN mode is preferable.

In the VA mode liquid crystal cell, rod-like liquid crystalline molecules are oriented substantially vertically when no voltage is applied. VA
The mode liquid crystal cell includes (1) a VA mode liquid crystal cell in a narrow sense in which rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied and are aligned substantially horizontally when voltage is applied (Japanese Patent Application Laid-Open No. 2-176625). (2) In order to widen the viewing angle, the VA mode is multi-domain (M
VA mode liquid crystal cell (SID97, Digest of tec)
h. Papers (Proceedings) 28 (1997) 845),
(3) A liquid crystal cell of a mode (n-ASM mode) in which rod-shaped liquid crystal molecules are substantially vertically aligned when no voltage is applied and twisted in a multi-domain alignment when a voltage is applied (Proceedings of Japan Liquid Crystal Conference 58-59 (1998). ) Description), (4) SU
Includes RVAIVAL mode liquid crystal cells (announced at LCD International 98) and (5) CPA mode liquid crystal cells (announced at SID'01).

The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystal molecules are aligned in substantially opposite directions (symmetrically) in the upper part and the lower part of the liquid crystal cell. No. 4,583,825 and U.S. Pat. No. 5,410,422. Since the rod-shaped liquid crystalline molecules are symmetrically aligned in the upper part and the lower part of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is
(Optically Compensatory Bend) Also called liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

In the TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and further twisted and aligned at 60 to 120 °. The TN mode liquid crystal cell is most often used as a color TFT liquid crystal display device, and is described in many documents. In the ECB mode liquid crystal cell, rod-shaped liquid crystal molecules are substantially horizontally aligned when no voltage is applied. The ECB mode is one of the liquid crystal display modes having the simplest structure and is described in many documents.

[0103]

EXAMPLES Example 1 A light-transmitting resin forming a light-scattering layer is an ultraviolet curable resin (Desolite Z7526JSR).
Crosslinked styrene beads (SX1 manufactured by Soken Chemical Co., Ltd., manufactured by Soken Kagaku Co., Ltd.) having 100 parts by mass of a refractive index of 1.51 as transparent fine particles.
30H, particle diameter 1.3 μm, refractive index 1.61) 33 parts by mass, crosslinked styrene beads (SX350H manufactured by Soken Kagaku,
11 parts by mass of a particle size of 3.5 μm and a refractive index of 1.61), mixed with these and adjusted to a solid content of 50% with methyl ethyl ketone / methyl isobutyl ketone (20/80 mass ratio), triacetyl Coating on a cellulose film (TD-80U, manufactured by Fuji Photo Film Co., Ltd.) to a dry film thickness of 4.0 μm, followed by solvent drying, followed by 16
Using an air-cooled metal halide lamp of 0 W / cm (manufactured by Eye Graphics Co., Ltd.), an illuminance of 400 mW / cm ² ,
A light-scattering film (HKF-01) was prepared by irradiating the coating layer with ultraviolet rays having an irradiation dose of 300 mJ / cm ² .

Haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K-7105
Was used to measure the haze (haze value) of HKF-01, which was 55%, which was an appropriate haze. The surface roughness was 0.16 μm, and the angle distribution from the surface of the surface irregularities was measured using Surface Explore SX-520. The average angle of the distribution was 4.0 °, and the maximum peak of the distribution was obtained. The angle was 1.0 °. The cross section of the film is cut with a microtome (CM1510, manufactured by Leica Co., Ltd.), and an electron microscope (S3500N / H) is used.
It was 0.03 μm when the penetration depth of the solvent into the transparent substrate was measured.

[Example 2] As the light-transmitting resin constituting the light-scattering layer, a hard coat coating solution containing a zirconium oxide dispersion (Desolite KZ-7114A, manufactured by JSR Corporation) was used.
00 parts, translucent resin (DPHA manufactured by Nippon Kayaku) 43
5 parts by mass of a curing initiator (Irgacure 184, manufactured by Ciba-Geigy Co., Ltd.), which are mixed with stirring with an air disperser and dissolved in a methyl ethyl ketone / methyl isobutyl ketone (20/80 mass ratio) solution,
The refractive index of the coating film obtained by coating and UV curing is 1.64.
Met. 21 parts by mass of polymethylmethacrylate beads (MX150 manufactured by Soken Chemical Industry Co., Ltd., particle size 1.5 μm, refractive index 1.49) as translucent particles, and polymethylmethacrylate beads (Soken Chemical Industry Co., Ltd., MX
300 particle diameter 3.0 μm, refractive index 1.49) 8.5 parts by mass, these are mixed and solid content 53 with methyl ethyl ketone / methyl isobutyl ketone (20/80 mass ratio)
% Triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd., TD-80)
U) was applied to a dry film thickness of 2.7 μm, solvent-dried, and an illuminance of 400 W was obtained using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm.
Light-scattering film (HKF-02) by curing the coating layer by irradiating with ultraviolet rays of mW / cm ² and a dose of 300 mJ / cm ^2.
Was produced.

Haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K-7105
Was used to measure the haze (haze value) of HKF-02, which was 63%, which was an appropriate haze. The surface roughness is 0.15 μm, and the angular distribution from the surface of the surface irregularities is measured using Surface Explore SX-520, the average angle of the distribution is 3.5 °, and the maximum peak of the distribution. The angle was 1.0 °. The cross section of the film is cut with a microtome (CM1510, manufactured by Leica Co., Ltd.), and an electron microscope (S3500N / H) is used.
The depth of penetration of the solvent into the transparent substrate was measured and the result was 0.02 μm.

[Example A] As the light-transmitting resin constituting the light-scattering layer, a hard coat coating solution containing a zirconium oxide dispersion (Desolite KZ-7114A, manufactured by JSR Corporation) was used.
00 parts, translucent resin (DPHA, manufactured by Nippon Kayaku Co., Ltd.) 43 parts by mass, and curing initiator (manufactured by Ciba-Geigy Co., Ltd., Irgacure 184) 5 parts by mass, which are mixed with stirring with an air spa. And then dissolved in a methyl ethyl ketone / methyl isobutyl ketone (20/80 mass ratio) solution, and then applied and UV cured to obtain a coating film having a refractive index of 1.
It was 64. Polymethyl methacrylate beads (Soken Chemical MX15
0, particle size 1.5 μm, refractive index 1.53) 21 parts by mass,
And 8.5 parts by mass of polymethylmethacrylate beads (MX300, particle size: 3.0 μm, refractive index: 1.53, manufactured by Soken Chemical Co., Ltd.), mixed with methyl ethyl ketone /
A triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd., TD) prepared by adjusting the solid content to 53% with methyl isobutyl ketone (10/90 mass ratio)
-80 U) to give a dry film thickness of 2.7 μm, solvent drying, and irradiation with an illumination of 400 mW / cm ² using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.). the amount 300 mJ / cm ² of ultraviolet rays are irradiated to cure the coated layer light scattering film (HKF-
03) was prepared.

Haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K-7105
Was used to measure the haze (haze value) of HKF-02, which was 63%, which was an appropriate haze. The surface roughness is 0.15 μm, and the angular distribution from the surface of the surface irregularities is measured using Surface Explore SX-520, the average angle of the distribution is 3.5 °, and the maximum peak of the distribution. The angle was 1.0 °. The cross section of the film is cut with a microtome (CM1510, manufactured by Leica Co., Ltd.), and an electron microscope (S3500N / H) is used.
When the depth of penetration of the solvent into the transparent substrate was measured by observing with, the result was 0.01 μm.

(Preparation of coating liquid for low refractive index layer) Refractive index 1.
42 thermally crosslinkable fluoropolymers (JN-7228, J
SRK Co., Ltd. 93g MEK-ST (average particle size 10
20 nm, methyl ethyl ketone (MEK) dispersion of SiO2 sol having a solid content concentration of 30% by mass, manufactured by Nissan Chemical Co., Ltd.
8 g and 100 g of methyl ethyl ketone were added and stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating liquid for low refractive index layer.

[Example 3] The above-mentioned coating liquid for low refractive index layer was applied onto the light scattering layer of HKF-01 by using a bar coater, dried at 80 ° C, and then thermally crosslinked at 120 ° C for 10 minutes. Then, a low-refractive index layer having a thickness of 0.096 μm was formed to prepare a light scattering film (HKHB-01).

Example 4 The above low refractive index layer coating solution was applied onto the light scattering layer of HKF-02 using a bar coater, dried at 80 ° C., and then thermally crosslinked at 120 ° C. for 10 minutes. Then, a low-refractive index layer having a thickness of 0.096 μm was formed to prepare a light scattering film (HKHB-02).

[Example B] The above low refractive index layer coating solution was applied onto the light scattering layer of HKF-03 using a bar coater, dried at 80 ° C, and then thermally crosslinked at 120 ° C for 10 minutes. Then, a low-refractive index layer having a thickness of 0.096 μm was formed and a light-scattering film (HKHB-03) was produced.

[Comparative Example 1] The light-transmitting resin forming the light-scattering layer was an ultraviolet-curable resin (Desolite Z7526JSR).
Benzoguanamine / melamine formaldehyde beads (made by Nippon Shokubai, particle diameter 0.5 μm, refractive index 1.6).
8) 12 parts by mass, crosslinked styrene beads (manufactured by Soken Kagaku)
SX350H, particle size 3.5μm, refractive index 1.61) 1
1 part by mass, a mixture of these materials, adjusted to have a solid content of 50% with methyl ethyl ketone / acetone (40/60 mass ratio), was used as a triacetyl cellulose film (Fuji Photo Film Co., Ltd., TD-80U). After coating on the top to dry film thickness of 3.0 μm and solvent drying,
Using an air-cooled metal halide lamp of 0 W / cm (manufactured by Eye Graphics Co., Ltd.), an illuminance of 400 mW / cm ² ,
A light-scattering film (HKF-H1) was prepared by irradiating the coating layer with ultraviolet rays having an irradiation dose of 300 mJ / cm ² .

Haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K-7105.
When the haze (cloudiness value) of HKF-01 was measured using 50%, it was 50%, which was an appropriate haze, but the surface roughness was 0.35 μm, and the angular distribution from the surface of the surface irregularities was When measured using Surface Explore SX-520, the average angle of the distribution was 6.5 ° and the maximum peak angle of the distribution was 1.6 °. The cross section of the film is cut with a microtome (CM1510, manufactured by Leica Co., Ltd.), and an electron microscope (S3500N / H) is used.
The penetration depth of the solvent into the transparent substrate was measured and was 1.20 μm.

[Comparative Example A] The light-transmitting resin forming the light-scattering layer was an ultraviolet-curing resin (Desolite Z7401, JS).
R-made, refractive index: 1.61) in 100 parts by mass as translucent fine particles to form crosslinked styrene beads (SX13 manufactured by Soken Kagaku).
12 parts by mass of OH, particle diameter 1.3 μm, refractive index 1.61), crosslinked styrene beads (SX350H manufactured by Soken Kagaku,
11 parts by mass of a particle size of 3.5 μm and a refractive index of 1.61) were mixed and adjusted to a solid content of 50% with methylethylketone / cyclohexanone (40/60 mass ratio). (TD-80U, manufactured by Fuji Photo Film Co., Ltd.), coated to a dry film thickness of 2.0 μm, dried with a solvent, and then subjected to 160 W
/ Cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) is used to irradiate ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² to cure the coating layer, and thus a light scattering film (HKF-H2). Was produced.

Haze meter MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K-7105
Was used to measure the haze (haze value) of HKF-H2, it was 25%, which was an appropriate haze. The surface roughness was 0.35 μm, and the angle distribution from the surface of the surface irregularities was measured using Surface Explore SX-520, and the average angle of the distribution was 6.5 °, and the maximum peak of the distribution. The angle was 1.6 °. The cross section of the film is cut with a microtome (CM1510, manufactured by Leica Co., Ltd.), and an electron microscope (S3500N / H) is used.
The penetration depth of the solvent into the transparent substrate was measured and was 1.50 μm.

(Evaluation of Antireflection Film) The obtained light-scattering film was evaluated for the following items. (1) A specular reflectance and tint spectrophotometer V-550 (manufactured by JASCO Corporation) was equipped with an adapter ARV-474, and an emission angle of -5 at an incident angle of 5 ° in a wavelength range of 380 to 780 nm. The specular reflectance was measured, the average reflectance from 450 to 650 nm was calculated, and the antireflection property was evaluated.

(2) Haze The haze of the obtained film is measured by a haze meter MODEL.
It measured using 1001DP (made by Nippon Denshoku Industries Co., Ltd.).

(3) Pencil hardness evaluation As an index of scratch resistance, the pencil hardness evaluation described in JIS K 5400 was performed. Anti-reflection film temperature 25 ℃, humidity 60
After conditioning the humidity for 2 hours at% RH, no scratches were observed in the evaluation of n = 5 with a load of 1 kg using a test pencil of 3H specified in JIS S 6006: In the evaluation of A n = 5 1 or 2 scratches: 3 or more scratches in the evaluation of B n = 5: C

(4) Contact angle measurement As an index of surface stain resistance (fingerprint adhesion), the optical material was conditioned for 2 hours at a temperature of 25 ° C. and a humidity of 60% RH, and then the contact angle with water was measured.

(5) Dynamic Friction Coefficient Measurement Dynamic friction coefficient was evaluated as an index of surface slipperiness. The coefficient of kinetic friction was adjusted to 5 mmφ with a HEIDON-14 kinetic friction meter after conditioning the sample for 2 hours at 25 ° C and 60% relative humidity.
Stainless steel ball, load 100g, speed 60cm / min
The value measured in 1. was used.

(6) Evaluation of antiglare property Exposed fluorescence without louvers on the created light diffusion film
Light (8000 cd / m ²) Of the reflected image
The degree was evaluated according to the following criteria. I don't know the outline of fluorescent lamps at all: A The outline of the fluorescent lamp is slightly visible: B The fluorescent light is blurred, but the outline is recognizable: C Almost no blur of fluorescent light: D

(7) Adhesion Evaluation The films obtained in the examples were bonded together with an adhesive so that the light diffusion layer was on the glass surface side, and aging was carried out at 50 ° C. and 5 atm for 6 hours. Set this polarizing plate at 25 ° C, 6
Under the condition of 0% RH, it was peeled from the glass surface and evaluated by the number of pieces remaining on the glass surface (test number: 100). As a comparative control, the solvent of Example A was replaced with methyl isobutyl ketone 1
Change to 00% by mass, and soak amount is 0.0005 μm
Adhesion evaluation is 95/100 (test number 1
95 out of 00 sheets were peeled between the support and the light scattering layer, and the light scattering layer was left on the glass).

Table 1 shows the results of Examples and Comparative Examples. The following are clear from the results shown in Table 1. The light-scattering films of Examples 3, 4, and B also have excellent adhesion and antiglare properties. Comparative Examples 1 and A have good adhesion, but poor antiglare properties.

[0125]

[Table 1]

Next, a polarizing plate was prepared using the film of the above-mentioned example, and evaluation was carried out in a liquid crystal display device.

<Production of Viewing Side Polarizing Plate SHB-01> Iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizing film. HKHB-01 is saponified and treated with polyvinyl alcohol adhesive to produce HKHB-01.
The transparent substrate film (triacetyl cellulose film) of -01 was attached to one side of the polarizing film so that the film was on the polarizing film side. Further, an optical compensation film WVSA12B (manufactured by Fuji Photo Film Co., Ltd.) having an optically anisotropic layer made of a liquid crystal compound is saponified, and a polyvinyl alcohol adhesive is used to make the film support have a polarizing film side. I stuck it on the other side so that In this way, a viewing side polarizing plate (SHB-01) was produced.

<Production of Viewing Side Polarizing Plate SHB-02> Iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizing film. HKHB-02 is saponified and treated with polyvinyl alcohol adhesive to produce HKHB-02
The transparent substrate film (triacetyl cellulose film) of No. -02 was attached to one side of the polarizing film so that the film was on the polarizing film side. Further, an optical compensation film WVSA12B (manufactured by Fuji Photo Film Co., Ltd.) having an optically anisotropic layer made of a liquid crystal compound is saponified, and a polyvinyl alcohol adhesive is used to make the film support have a polarizing film side. I stuck it on the other side so that In this way, the viewing side polarizing plate (SHB-02) was produced.

<Production of Viewing Side Polarizing Plate SHB-03> Iodine was adsorbed on a stretched polyvinyl alcohol film to produce a polarizing film. HKHB-03 is saponified and treated with polyvinyl alcohol adhesive to produce HKHB-03
The transparent substrate film of No. -03 (triacetyl cellulose film) was attached to one side of the polarizing film so that the film was on the polarizing film side. Further, an optical compensation film WVSA12B (manufactured by Fuji Photo Film Co., Ltd.) having an optically anisotropic layer made of a liquid crystal compound is saponified, and a polyvinyl alcohol adhesive is used to make the film support have a polarizing film side. I stuck it on the other side so that In this way, a viewing side polarizing plate (SHB-03) was produced.

<Production of Backlight-Side Polarizing Plate BHB-01> Iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizing film. A commercially available triacetyl cellulose film (Fujitac TD80 manufactured by Fuji Photo Film Co., Ltd.) was saponified, and a polyvinyl alcohol-based adhesive was used to attach the film to one side of the polarizing film. Also, an optical compensation film WVSA12B (Fuji Photo Film Co., Ltd.) having an optically anisotropic layer made of a liquid crystal compound is used.
Saponification treatment was performed, and a polyvinyl alcohol-based adhesive was used to attach the cellulose acetate film to the opposite side so that the film was on the polarizing film side. In this way, a backlight side polarizing plate (BHB-01) was produced.

[Example 5] A pair of polarizing plates provided in a liquid crystal display device (6E-A3, manufactured by Sharp Corporation) using a TN type liquid crystal cell was peeled off, and a polarizing plate (SHB was used instead).
-01) was attached to the observer side via an adhesive so that the optical compensation film was on the liquid crystal cell side. Further, on the backlight side, a polarizing plate (BHB-0) on the backlight side is provided via an adhesive so that the optical compensation film is on the liquid crystal cell side.
1) was pasted. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be in the O mode. About the manufactured liquid crystal display device, using a measuring instrument (EZ-Contrast160D, manufactured by ELDIM), the viewing angle in 8 stages from black display (L1) to white display (L8), and color in halftone (L3) The taste change was measured. The results are shown in Table 2.

Example 6 A pair of polarizing plates provided in a liquid crystal display device (6E-A3, manufactured by Sharp Corporation) using a TN type liquid crystal cell was peeled off, and a polarizing plate (SHB) was used instead.
-02) was attached to the observer side via an adhesive so that the optical compensation film was on the liquid crystal cell side. Further, on the backlight side, a polarizing plate (BHB-0) on the backlight side is provided via an adhesive so that the optical compensation film is on the liquid crystal cell side.
1) was pasted. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be in the O mode. About the manufactured liquid crystal display device, using a measuring instrument (EZ-Contrast160D, manufactured by ELDIM), the viewing angle in 8 stages from black display (L1) to white display (L8), and color in halftone (L3) The taste change was measured. The results are shown in Table 2.

[Example C] A pair of polarizing plates provided in a liquid crystal display device (6E-A3, manufactured by Sharp Corporation) using a TN type liquid crystal cell was peeled off, and a polarizing plate (SHB was used instead).
-03) was attached to the observer side via an adhesive so that the optical compensation film was on the liquid crystal cell side. Further, on the backlight side, a polarizing plate (BHB-0) on the backlight side is provided via an adhesive so that the optical compensation film is on the liquid crystal cell side.
1) was pasted. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be in the O mode. About the manufactured liquid crystal display device, using a measuring instrument (EZ-Contrast160D, manufactured by ELDIM), the viewing angle in 8 stages from black display (L1) to white display (L8), and color in halftone (L3) The taste change was measured. The results are shown in Table 2.

[Comparative Example 2] A pair of polarizing plates provided in a liquid crystal display device (6E-A3, manufactured by Sharp Corporation) using a TN type liquid crystal cell was peeled off, and a commercially available polarizing plate (manufactured by Sanritz) was used instead. LL-82-12WNA) was attached. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be in the O mode. About the manufactured liquid crystal display device, a measuring machine (EZ-Contrast
160D, manufactured by ELDIM), using black display (L1)
From 8 to white display (L8), the viewing angle and the change in tint in the halftone (L3) were measured. The results are shown in Table 2.

[0135]

[Table 2]

As described above, the light-scattering film, polarizing plate and liquid crystal display device of the present invention exhibit excellent viewing angle characteristics.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a light-scattering film of the present invention.

[Explanation of symbols]

10 Light scattering film 20 Transparent support 30 light scattering layer 41 Matt particles 1 42 Matt particles 2 50 Low refractive index layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/1335 510 C08L 1:12 // C08L 1:12 G02B 1 / 10A F term (reference) 2H042 BA02 BA12 BA14 BA15 BA20 2H049 BA02 BA27 BA42 BB03 BB33 BB43 BB51 BB63 BB65 BC02 BC09 BC12 BC22 2H091 FA08X FA08Z FA32X FB02 FB13 GA16 LA18 LA19 2K009 AA04 BB28 CC09 CC26 DD02 DD06 EE03 4F006 AB56 AB06 AB16

Claims (10)

[Claims] 1. A light-scattering film having a light-scattering layer on a transparent substrate, wherein the light-scattering layer comprises a light-transmitting resin and light-transmitting fine particles, and the light-scattering layer has a thickness of 2.0 to 6.0 μm. The thickness of the transparent resin is 0.0% from the surface of the transparent substrate.
A light-scattering film having a depth of 1 to 1 μm. 2. The light scattering layer has a thickness of 0.05 μm to 0.18 μm.
The light-scattering film according to claim 1, which has a surface roughness of m. 3. The light-scattering film according to claim 1, wherein the light-scattering layer has a haze value of 40% or more. 4. The light scattering film according to claim 1, wherein a low refractive index layer is provided on the light scattering layer. 5. A coating solution is prepared by dissolving or dispersing a transparent resin and transparent fine particles in a mixed solvent containing a solvent in which the transparent substrate is soluble and a solvent in which the transparent substrate is insoluble. A method for producing a light-scattering film, comprising: a step of applying a coating solution onto a transparent substrate; and a step of forming a light-scattering layer by drying, wherein the light-scattering layer has a thickness of 2.0 to 6.0 μm. 2. The method for producing a light-scattering film, wherein the transparent resin has a thickness of 0.1 to 1 μm from the surface of the transparent substrate. 6. The method for producing a light-scattering film according to claim 5, wherein the transparent base material is a cellulose acetate film, and the solvent in which the transparent base material dissolves is a ketone. 7. A polarizing plate in which both sides of a polarizing film are sandwiched by two protective films, one protective film being the light-scattering film according to any one of claims 1 to 4. . 8. A polarizing plate having the light-scattering film according to any one of claims 1 to 4, a polarizing film, a transparent support, and an optically anisotropic layer composed of a liquid crystalline compound in this order. 9. The polarizing plate according to claim 8, wherein the liquid crystal compound is a discotic compound. 10. A liquid crystal display device in which both surfaces of a liquid crystal cell are sandwiched between two polarizing plates, and the polarizing plate on the display surface side is the polarizing plate according to any one of claims 7 to 9. Liquid crystal display device.