JP2009086341A - Light scattering film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

Provided are a light scattering film, a polarizing plate, and a liquid crystal display device that improve both luminance asymmetry and color change over a wide range of viewing angles with respect to a display.
The support has a light scattering layer formed of at least one kind of light scattering particles, a translucent resin, and a dispersant, and the layer thickness (R) of the light scattering layer is light scattering. The particle size (d) of the particle 2 is 1.4 times or more and 4.0 times or less, and the refractive indexes of the light scattering particles 2 at wavelengths of 435 nm and 545 nm are n _P435 and n _P545 , respectively, and 435 nm of the translucent resin. And a light scattering film that simultaneously satisfies the following mathematical formulas (1) to (3), where n _B435 and n _B545 are refractive indexes at 545 nm, respectively. Formula (1): n _B435 > n _P435 Formula (2): n _B545 > n _P545 Formula (3): 0.9 <(n _P435 / n _B435 ) / (n _P545 / n _B545 ) <1.0
[Selection] Figure 1

Description

  The present invention relates to a light scattering film, a polarizing plate, and a liquid crystal display device that improve both luminance asymmetry and color change in a wide range of viewing angles.

  Image display devices represented by liquid crystal displays (LCDs), plasma display panels (PDPs), CRTs, ELs and the like are used in various fields including televisions and computers, and have made remarkable progress. In particular, the LCD is a thin, lightweight and versatile display, and is widely used as a display medium for flat-screen televisions, mobile phones, personal computers, digital cameras, PDAs, and other various devices.

  As LCD display formats, display devices such as a TN mode, a VA mode, an IPS mode, and an OCB mode have been developed. The display formats of these liquid crystal display devices are different in the alignment mode of the liquid crystal, and exhibit image display characteristics specific to the alignment mode of each liquid crystal. For the TN mode developed in the early stage and the OCB mode with improved response speed, viewing angle luminance asymmetry (change in contrast value depending on viewing angle direction) and viewing angle color asymmetry (change in light color depending on viewing angle direction) ) And the viewing angle performance needs to be supplemented by a retardation film or a light scattering film. In particular, recently, the trend of increasing the size of display devices is accelerating, and the visual asymmetry described above has a greater effect on the comfort when using the display device.

On the other hand, in an optical functional film used for a display member such as an LCD or PDP, functional layers corresponding to various uses are laminated on a support such as triacetyl cellulose (TAC) or polyethylene terephthalate (PET). . Among these, the light scattering film that scatters the transmitted light of the display and improves the display angle luminance asymmetry inherent to the display is based on the difference in refractive index between the resin raw material component for forming the translucent resin and the translucent resin. It is composed of light scattering particles for scattering transmitted light. It is known that the light scattering film exhibits an effect of improving the asymmetry of viewing angle luminance with respect to an image display device having viewing angle asymmetry such as the OCB mode and TN mode (see, for example, Patent Document 1). ).
JP 2006-259003 A

  However, in the conventional light scattering film, the viewing angle luminance asymmetry is improved, but in terms of viewing angle color asymmetry, a bluish change may occur, and improvement has been desired.

The dependence of the refractive index on the wavelength is called chromatic dispersion. When the wavelength dependence of the refractive index is small, the chromatic dispersion of the refractive index is small. In general, the wavelength dispersion of the refractive index of a substance used for a translucent resin or light scattering particles has the following characteristics. First, the refractive index of a substance tends to increase as the wavelength becomes shorter.
Secondly, the higher the refractive index, the stronger the refractive index tends to increase as the wavelength becomes shorter.

  Therefore, in the case of producing a light scattering film in which light-transmitting particles having a relatively low refractive index are dispersed in a light-transmitting resin having a relatively high refractive index, the refraction of the light-transmitting particles is generally used. The wavelength dispersibility of the refractive index is smaller than that of the translucent resin, and the refractive index difference between the two increases in the short wavelength region. As a result, light scattering of short wavelength components increases in the film, and the phenomenon that the scattered light is bluish easily occurs. Therefore, when a light scattering film is installed on the surface of a liquid crystal display device, an effect of improving luminance asymmetry can be obtained, but the degree of scattering differs depending on the wavelength, and the change in color may be large.

  In view of the above problems, an object of the present invention is to provide a light scattering film, a polarizing plate, and a liquid crystal display device that improve both luminance asymmetry and color change in a wide range of viewing angles.

  As a result of intensive studies, the present inventors have found that the above problems can be improved by a light scattering film, a polarizing plate, and a liquid crystal display device using the same.

1. A light scattering film having a light scattering layer formed of at least one kind of light scattering particles, a translucent resin, and a dispersant on a support, wherein the layer thickness (R) of the light scattering layer is that of the light scattering particles. At least one metal oxide fine particle selected from titanium, zinc, and aluminum having a particle size of 1.4 to 4.0 times the particle size (d) and having a particle size of translucent resin of 100 nm or less. When the refractive index of at least one kind of light scattering particles at wavelengths 435 nm and 545 nm is n _P435 and n _P545 , respectively, and the refractive index at 435 nm and 545 nm of the translucent resin is n _B435 and n _B545 , respectively. The light-scattering film characterized by satisfy | filling following numerical formula (1)-(3) simultaneously.
Formula (1): n _B435 > n _P435
Formula (2): n _B545 > n _P545
Formula (3): 0.9 <(n _P435 / n _B435 ) / (n _P545 / n _B545 ) <1.0
2. 2. The light scattering film according to 1, wherein when the spectral transmittances at wavelengths of 435 nm and 545 nm are T ₄₃₅ and T ₅₄₅ , respectively, the following formula (4) is further satisfied.
Formula (4): 0.33 < _T435 / _T545 <1.25
3. The light scattering film according to 1 or 2, further satisfying the following formula (5):
Formula (5): 1.005 <n _B435 / n _B545 <1.360
4). 4. The light scattering film according to any one of 1 to 3, wherein the compound constituting the light scattering particles includes a compound having an aromatic ring.
5). 5. The light scattering film according to any one of 1 to 4, wherein the dispersant is an anionic dispersant.
6). The polarizing plate which has a polarizing film and a protective film on both sides of this polarizing film, Comprising: At least one protective film is a light-scattering film in any one of 1-5.
7). An image display device having the light scattering film according to any one of 1 to 5 or the polarizing plate according to 6.
8). A liquid crystal display device having a TN mode or OCB mode liquid crystal cell, comprising the light scattering film according to any one of 1 to 5 or the polarizing plate according to 6.

  ADVANTAGE OF THE INVENTION According to this invention, the light-scattering film and polarizing plate which improved both the luminance asymmetry and the color change in a wide viewing angle are obtained. In addition, according to the present invention, a light scattering film particularly suitable for a display having a viewing angle asymmetry (TN mode or OCB mode) is provided by using a light scattering film in which both luminance asymmetry and color change are improved. be able to. Furthermore, according to this invention, the image display apparatus using the light-scattering film of this invention can be provided.

Embodiments of the present invention will be described below.
The light scattering film of the present invention is a light scattering film having a light scattering layer formed of light scattering particles, a translucent resin and a dispersant on a support, and the light scattering layer thickness (d) and light The relationship of the average particle diameter (R) of the scattering particles is within a specific range, the translucent resin has specific oxide fine particles, and the light scattering particles and the translucent resin each have a specific refractive index. It is characterized by satisfying the characteristics.
This will be described in more detail below.

<Light scattering film>
(Light scattering layer)
The light scattering layer, which is an essential constituent layer in the light scattering film of the present invention, is a layer formed from at least one kind of light scattering particles, a light-transmitting resin, and a dispersant, and the light scattering particles are light-transmitting. It is formed by being dispersed in a functional resin.

[Formation material of light scattering layer]
Hereinafter, the material for forming the light scattering layer will be described.

(Translucent resin)
The translucent resin, which is an indispensable material for forming the light scattering layer, is a resin composition in which oxide fine particles having a specific particle diameter are mixed with a resin component.

(Resin component)
The resin component is not particularly limited as long as the following mathematical formulas (1) to (3) are satisfied in relation to the light scattering particles. Thermoplastic resins, thermosetting resins, ionizing radiation curable resins Can be used as appropriate.

  As thermoplastic resins, polymethyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), norbornene-containing resin, polyethersulfone Various resins such as these can be used. These may be used alone or in combination.

  Examples of thermosetting resins include furan resins, ketone / formaldehyde resins, urea resins, aniline resins, alkyd resins, unsaturated polyester resins, and epoxy resins. These may be used alone or in combination.

The ionizing radiation curable resin is particularly preferable among the above-exemplified resins from the viewpoint of increasing the hardness of the cured film. In the present invention, a resin obtained by curing a monomer having two or more polymerizable functional groups is used. Can be. That is, a resin is formed in the obtained light-scattering layer by making it exist as a monomer in the coating material for forming the light-scattering layer and performing a curing reaction after forming a coating film.
The polymerizable functional group possessed by the monomer is preferably a light, electron beam or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable. Examples of the photopolymerizable functional group include polymerizable functional groups such as an ethylenically unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among these, a (meth) acryloyl group is preferable.

  Examples of monomers having two or more ethylenically unsaturated groups that are photopolymerizable include esters of polyhydric alcohols and (meth) acrylic acid {eg, ethylene glycol di (meth) acrylate, 1,4-dichloro Hexane diacrylate, 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, etc.}, Rusuruhon (e.g. divinyl sulfone), acrylamides (e.g., methylenebisacrylamide, etc.). Among these, an acrylate or methacrylate monomer having at least three functional groups, 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 is particularly preferably used.

  As the ionizing radiation curable resin, a compound having a crosslinkable functional group can be used instead of the monomer having the polymerizable unsaturated group or in addition to the monomer having the polymerizable unsaturated group. Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as the compound having a crosslinkable functional group. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition. These compounds having a crosslinkable functional group form a crosslinked structure by heating after coating.

  In the present invention, it is also possible to use a high refractive index resin such as a sulfur-containing resin or an aromatic resin in order to adjust the refractive index and satisfy each formula described later. Specifically, examples of the sulfur-containing resin include polythiophene, polythiol, thiourethane resin, episulfide resin, and the like. Examples of the aromatic-containing resin include benzene-based aromatic compounds (resins having a phenyl group, a biphenyl group, etc.), Aromatic polycyclic compounds (resins having a naphthyl group, anthracenyl group, etc.), condensed ring compounds, heteroaromatic compounds and the like can be mentioned.

(Oxide fine particles)
Oxide fine particles used in combination with the resin component are particles having smaller wavelength dispersion than organic translucent resins, and are oxide fine particles of at least one metal selected from titanium, zinc, and aluminum. These composite fine particles can also be used. These oxide fine particles are excellent in terms of improving the strength of the film, and also in terms of manufacturing cost and simplicity.
Specifically, titanium oxide particles having a diameter of about 15 nm modified with aluminum hydroxide on the surface, zinc oxide particles with a diameter of 10 to 40 nm modified with a silane coupling agent on the surface, and silane coupling on the surface as well. Examples thereof include aluminum oxide particles having a diameter of 50 nm that are hydrophobically modified with an agent.
In addition to the fine oxide particles of titanium, zinc and aluminum, the fine oxide particles include cobalt, indium, lead, antimony, vanadium, yttrium, lanthanum, cerium, niobium, tungsten, samarium, tantalum, neodymium, and the like. Since metal oxide fine oxide particles all have a high refractive index, they can be used in combination.
In the present invention, these oxide fine particles are mixed with the resin component and polymerized to form a high refractive index translucent resin dispersed in the oxide fine particle resin.
The specific particle size of the oxide fine particles is 100 nm or less, preferably 70 nm or less, and more preferably 10 to 50 nm. When the particle diameter exceeds 100 nm, the desired light scattering property cannot be obtained by adjusting the refractive index difference between the light-transmitting resin and the light scattering particles to the above-mentioned preferable range.
The oxide fine particles are used in a range of 5 to 250 parts by mass and preferably in a range of 10 to 200 parts by mass with respect to 100 parts by mass of the resin component. When the oxide fine particles other than the above-mentioned oxide fine particles of titanium, zinc and aluminum are used in combination, the oxide fine particles of titanium, zinc and aluminum are preferably 50 to 100% of the whole oxide fine particles used. 70 to 100% is more preferable.

(Light scattering particles)
In this invention, if the refractive index difference with translucent resin satisfies Numerical formula (1)-(3), there will be no restriction | limiting in the light-scattering particle which can be used.
In the present invention, the light scattering particles may be monodispersed organic fine particles or inorganic fine particles. As the particle size does not vary, the light scattering property varies less and the design of the light scattering film becomes easier. As the light scattering particles, plastic beads are preferable, and those having high transparency are particularly preferable.

The organic fine particles include polymethyl methacrylate beads (refractive index 1.49), acrylic-styrene copolymer beads (refractive index 1.54), melamine formaldehyde beads (refractive index 1.65), 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), etc. Used. Here, the refractive index described in parentheses () is a refractive index measured at a measurement wavelength of 545 nm.
As the inorganic fine particles, aggregated silica beads (refractive index 1.45) are generally used.

Moreover, in this invention, it is preferable that the compound which comprises light-scattering particle | grains contains the compound which has an aromatic ring. The compound which has an aromatic ring can mention preferably the compound obtained by introduce | transducing an aromatic group into the compound which comprises the above-mentioned organic fine particle.
In order to include a compound having an aromatic group, specifically, the light scattering particle is not particularly limited as long as the light scattering particle has an aromatic group. For example, only from a compound having an aromatic group in a structural unit. Either a method using resin particles or a method of forming resin particles by using a compound having an aromatic group and a compound having no aromatic group in the structural unit may be employed. In the latter case, the combined method of the compound having an aromatic group is addition, whether it is copolymerization with a compound having no aromatic group or introduction into a resin side chain by various chemical reactions. May be. In the present invention, the method preferably uses a compound having an aromatic group in the structural unit and a compound having no aromatic group in the structural unit.
Examples of the compound having an aromatic group in the structural unit include styrene, methylstyrene, diallylbenzene, melamine, benzoguanamine and the like. In particular, methylol melamine, which is a raw material of melamine resin, and an alcohol-modified product thereof and a compound containing a plurality of hydroxyl groups in the molecule are preferable because of their wide mixing ratio and the range of selection of the compound having a hydroxyl group. These may be used alone or in combination.
Examples of the aromatic group that can be introduced into the compound constituting the light scattering particle include a phenyl group, a biphenyl group, a naphthyl group, an anthracenyl group, and various condensed rings and heteroaromatic rings. As the introduction ratio of the aromatic group, when the aromatic group is introduced into the light scattering particle, the ratio of the structural unit containing the aromatic group in all the structural units is 5 mol% or more and 40 mol% or less. Preferably, it is 10 mol% or more and 30 mol% or less, more preferably 15 mol% or more and 20 mol% or less. When the aromatic compound is added, the weight ratio of the aromatic compound to the total solid content is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and more preferably 15% by mass. It is most preferable that it is 20% by mass or more. In any of the methods, the higher the ratio of the aromatic component, the shorter the refractive index of the short wavelength increases, and a desirable effect is obtained. If it exceeds the mass%, the refractive index wavelength dispersibility increases excessively, and although the scattering of the blue component decreases, the scattering of the red component may increase conversely, so the above range is preferable.
The light scattering particles may be used alone or in combination. In the case of using a plurality of light scattering particles, at least one kind of particles mainly contribute to light scattering, but other particles may not contribute to scattering. Therefore, when using a plurality of types of particles, the method for selecting the particle type is not particularly limited as long as it is within a desired refractive index range. The use of resin particles is preferred.

  By reducing the wavelength dispersion of the translucent resin by means (2) described later, it becomes possible to use general-purpose resin particles that do not have the above-mentioned aromatic group.

  When the light scattering particles are contained in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of the light-transmitting resin, it is possible to design the film having both film hardness and scattering characteristics. It is still more preferable to make it contain 10-25 mass parts.

In the present invention, in order to obtain an appropriate scattering property, the particle diameter of the light scattering particles is preferably 0.5 to 6.0 μm, more preferably 0.8 to 5.0 μm, and most preferably 1.0 to 4.0 μm. By using particles having a particle size in this range, an angle distribution of light scattering suitable for the present invention can be obtained. When the particle size is 0.5 μm or more, it has an appropriate light scattering effect and good viewing angle characteristics, and backscattering is moderately suppressed and the decrease in brightness is small. On the other hand, when the thickness is 6.0 μm or less, there is no inconvenience such as a small light scattering effect and a small improvement in viewing angle characteristics. When the size of the light scattering particle is less than 3.0 μm, the wavelength dependence of light scattering by the particle itself tends to increase, and the scattering of light with a short wavelength becomes strong. In this region, in particular, the relationship between the refractive index wavelength dispersion of the translucent resin and the light scattering particles, that is, the value of (n _P435 / n _B435 ) / (n _P545 / n _B545 ) in Equation (3) (hereinafter referred to as K value). However, it is important to make it difficult to scatter short wavelengths. Therefore, the K value is preferably less than 1.0.

  In the present invention, the shape of the light scattering particles is not particularly limited, and various shapes such as a spherical shape, a flat shape, and a spindle shape can be taken, but a spherical shape is preferable.

(Inorganic filler)
When the light scattering particles as described above are used, the light scattering particles easily settle in the translucent resin. Therefore, an inorganic filler such as silica may be added to prevent the precipitation. As the amount of the inorganic filler added increases, it is more effective in preventing the sedimentation of the translucent fine particles, but adversely affects the transparency of the coating film. Accordingly, preferably, an inorganic filler having a particle size of 0.5 μm or less, more preferably 0.01 to 0.2 μm, is used so that the transparency of the coating film is not impaired with respect to 100 parts by mass of the translucent resin. The content is preferably less than 0.1 parts by mass, and more preferably 0.01 to 0.08 parts by mass.

(Dispersant)
In the present invention, a dispersant is used for preventing sedimentation of light scattering particles in a light-transmitting resin, improving dispersion stability, and improving the dispersion stability of oxide fine particles present in the light-transmitting resin. In the present invention, it is particularly preferable to use an anionic dispersant having an anionic group for dispersing the light scattering particles and the oxide fine particles.

  As the anionic group, a group having an acidic proton such as a carboxyl group, a sulfonic acid group (and a sulfo group), a phosphoric acid group (and a phosphono group), or a sulfonamide group, or a salt thereof is effective. A sulfonic acid group, a phosphoric acid group and a salt thereof are preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. The number of anionic groups contained in the dispersant per molecule may be one or more.

  A plurality of anionic groups may be contained for the purpose of further improving the dispersibility of the fine particles. The average number is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.

  As the anionic group, an anionic polar group is preferable, and as the dispersant having an anionic polar group, phosphanol (PE-510, PE-610, LB-400, EC-6103, RE-410, etc .; Toho; Chemical Industry Co., Ltd.), Disperbyk (-110, -111, -116, -140, -161, -162, -163, -164, -170, -171, etc .; manufactured by Big Chemie Japan), Aronix M5300 Etc .; Toagosei Co., Ltd., KAYAMER (PM-21, PM-2 etc .; Nippon Kayaku Co., Ltd.) etc. are mentioned.

  The dispersant preferably further contains a crosslinkable or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acryloyl groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, and cationic polymerizable groups (epoxies). Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like, and functional groups having an ethylenically unsaturated group are preferred.

  The average number of cross-linkable or polymerizable functional groups contained in the dispersant per molecule is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the crosslinking or polymerizable functional group contained in the dispersant may contain a plurality of types in one molecule.

  The dispersant is a dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in a side chain. The weight average molecular weight (Mw) of the dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain is not particularly limited, but is preferably 1000 or more. . The more preferable mass average molecular weight (Mw) of the dispersant is 2000 to 1000000, more preferably 5000 to 200000, and particularly preferably 10000 to 100000. By using a dispersant in this molecular weight range, the dispersion stability of both the oxide inorganic fine particles and the light-scattering particles is improved, and the particle arrangement sufficient for the light-scattering particles to cause multiple scattering in the light-scattering layer. It becomes possible to take.

  The dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain has the anionic group in the side chain or terminal. Examples of the method for introducing an anionic group into the side chain include an anionic group-containing monomer (for example, (meth) acrylic acid, maleic acid, partially esterified maleic acid, itaconic acid, crotonic acid, 2-carboxyethyl (meth) acrylate. , Polymer reaction such as a method of polymerizing 2-sulfoethyl (meth) acrylate, mono-2- (meth) acryloyloxyethyl ester of phosphoric acid, a method of allowing an acid anhydride to act on a polymer having a hydroxyl group, an amino group, etc. Can be synthesized by using

In the dispersant having an anionic group in the side chain, the composition of the anionic group-containing repeating unit is in the range of 10 ^{−4 to} 100 mol%, preferably 1 to 50 mol%, particularly preferably 5 among all repeating units. ˜20 mol%.

  On the other hand, a dispersant having an anionic group at the terminal can also be preferably used. As a method for introducing an anionic group at the terminal, a polymerization reaction is performed in the presence of an anionic group-containing chain transfer agent (for example, thioglycolic acid). And a method of performing a polymerization reaction using an anionic group-containing polymerization initiator (for example, Wako Pure Chemical Industries, Ltd. V-501). Particularly preferred dispersants are those having an anionic group in the side chain.

In the preferred dispersant for use in the present invention, examples of the repeating unit having an ethylenically unsaturated group in the side chain include poly-1,2-butadiene and poly-1,2-isoprene structures or (meth) acrylic acid. An ester or amide repeating unit to which a specific residue (the R group of —COOR or —CONHR) is bonded can be used. Examples of the specific residue (R _{group), - (CH 2) n} -CR 1 = CR 2 R 3, - (CH 2 O) n-CH 2 CR 1 = CR 2 R 3, - (CH ₂ CH ₂ O) n-CH ₂ CR ₁ = CR ₂ R ₃ ,-(CH ₂ ) n-NH-CO-O-CH ₂ CR ₁ = CR ₂ R ₃ ,-(CH ₂ ) nO-CO-CR ₁ = CR ₂ R ₃ and — (CH ₂ CH ₂ O) ₂ —X (R _{1 to} R ₃ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, An aryloxy group, R ₁ and R ₂ or R ₃ may combine with each other to form a ring, n is an integer of 1 to 10 and X is a dicyclopentadienyl residue) Can be mentioned. Specific examples of the ester residue include —CH ₂ CH═CH ₂ (corresponding to an allyl (meth) acrylate polymer described in JP-A No. 64-17047), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , -CH ₂ CH ₂ OCOCH = CH ₂ , -CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , -CH ₂ C (CH ₃ ) = CH ₂ , -CH ₂ CH = CH-C ₆ H ₅ , _{-CH 2 CH 2 OCOCH = CH-} C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and -CH ₂ CH ₂ OX (X is a dicyclopentadienyl residue) are included. Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (Y is a 1-cyclohexenyl residue) and —CH ₂ CH ₂ —OCO—CH═CH ₂ , —CH ₂ CH ₂ —OCO—C (CH ₃ ) ═CH ₂ is included.

  In the dispersant having an ethylenically unsaturated group, a free radical (a polymerization initiation radical or a growth radical of a polymerization process of a polymerizable compound) is added to the unsaturated bond group, and the polymer compound is directly or between molecules. Addition polymerization is carried out through the polymerization chain, and a crosslink is formed between the molecules to cure. Alternatively, atoms in the molecule (for example, hydrogen atoms on carbon atoms adjacent to the unsaturated bond group) are extracted by free radicals to form polymer radicals that are bonded together to form a bridge between the molecules. Harden.

  A method for introducing a cross-linkable or polymerizable functional group into the side chain is, for example, as described in JP-A-3-249653, etc., a crosslinkable or polymerizable functional group-containing monomer (for example, allyl (meth) acrylate, glycidyl (meth) acrylate, Copolymerization of trialkoxysilylpropyl methacrylate, etc., copolymerization of butadiene or isoprene, copolymerization of vinyl monomers having a 3-chloropropionic acid ester moiety followed by dehydrochlorination, crosslinking or polymerization by polymer reaction Can be synthesized by introduction of a functional group (for example, polymer reaction of an epoxy group-containing vinyl monomer to a carboxyl group-containing polymer).

  The cross-linked or polymerizable functional group-containing unit may constitute all repeating units other than the anionic group-containing repeating unit, preferably 5 to 50 mol% of all repeating units, particularly preferably. 5 to 30 mol%.

  A preferable dispersant may be a copolymer with a suitable monomer other than a monomer having a crosslinking or polymerizable functional group or an anionic group. Although it does not specifically limit regarding a copolymerization component, It selects from various viewpoints, such as dispersion stability, compatibility with another monomer component, and the intensity | strength of a formed film. Preferable examples include methyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene and the like. The preferred dispersant form of the present invention is not particularly limited, but is preferably a block copolymer or a random copolymer, and particularly preferably a random copolymer from the viewpoint of cost and synthetic ease.

  Although the specific example of the dispersing agent preferably used for the present invention below is shown, it is not limited to these. Unless otherwise specified, it represents a random copolymer.

  The amount of the dispersant used is preferably in the range of 1 to 50 parts by mass, more preferably in the range of 3 to 30 parts by mass, with respect to 100 parts by mass of the total solid content of the light scattering layer, and more preferably 3 to 20 Most preferably, it is in the range of parts by mass. Two or more dispersants may be used in combination.

(Photopolymerization initiator)
As a material for forming the light scattering layer, it is preferable to add a photopolymerization initiator for curing the translucent resin by light irradiation. In particular, in the present invention, a photoradical polymerization initiator is used as the photoinitiator. desirable.

  Examples of photo radical polymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (JP-A-2001-139663, etc.), 2, Examples include 3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, and coumarins.

  These initiators may be used alone or in combination. “Latest UV Curing Technology”, Technical Information Association, 1991, p. 159, and “UV curing system” written by Kayo Kiyomi, 1989, General Technology Center, p. Various examples are also described in 65-148 and are useful in the present invention.

  As a commercially available photo radical polymerization initiator, “Kayacure (DETX-S, BP-100, BDDK, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC” manufactured by Nippon Kayaku Co., Ltd. , MCA, etc.), “Irgacure (651, 184, 500, 819, 907, 369, 1173, 1870, 2959, 4265, 4263, etc.)” manufactured by Ciba Specialty Chemicals Co., Ltd., “Esacure” manufactured by Sartomer (KIP100F, KB1, EB3, BP, X33, KT046, KT37, KIP150, TZT) "and the like, and combinations thereof are preferable examples.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of translucent resin, More preferably, it is the range of 1-10 mass parts.

(Surface improver)
In addition, it is preferable to add at least one of fluorine-based and silicone-based surface improvers to the light scattering layer in order to improve surface defects (coating unevenness, drying unevenness, point defects, etc.).

  The surface conditioner preferably changes the surface tension of the coating solution for forming the light scattering layer by 1 mN / m or more. Here, when the surface tension of the coating liquid changes by 1 mN / m or more, the surface tension of the coating liquid after the addition of the surface conditioner is added, including the concentration process during coating / drying. It means that it changes by 1 mN / m or more as compared with the surface tension of the coating liquid that has not been applied. Preferably, it is a surface conditioner that has the effect of lowering the surface tension of the coating solution by 1 mN / m or more, more preferably a surface conditioner that lowers by 2 mN / m or more, and particularly preferably a surface conditioner that lowers by 3 mN / m or more. .

  Preferable examples of the fluorine-based surface improver include compounds having a fluoroaliphatic group. Examples of preferred compounds include the compounds described in JP-A-2005-115359, JP-A-2005-221963, and JP-A-2005-234476.

In the light scattering film of the present invention, the specific refractive index characteristics satisfied by the light-transmitting resin and the light scattering particles are n _P435 and n _P545 , respectively, at the wavelengths 435 nm and 545 nm of the light scattering particles, When the refractive indexes of the translucent resin at wavelengths of 435 nm and 545 nm are n _B435 and n _B545 , respectively, the following formulas (1) to (3) are satisfied simultaneously.

Formula (1): n _B435 > n _P435
Formula (2): n _B545 > n _P545
Formula (3): 0.9 <(n _P435 / n _B435 ) / (n _P545 / n _B545 ) <1.005

[Formulas (1) to (3)]
Hereinafter, the mathematical formulas (1) to (3) will be described. In the present invention, as indicated by the mathematical formulas (1) and (2), the refractive index of the light scattering particles (hereinafter sometimes referred to as translucent particles) is lower than the refractive index of the translucent resin. is required. Light is scattered at the interface due to the difference in refractive index between the two.

  The refractive index of the translucent resin in the present invention is not particularly limited except that it is higher than the refractive index of the light scattering particles. However, when a general-purpose translucent resin and general-purpose light scattering particles are used, the wavelength is 545 nm. The refractive index of the translucent resin is preferably 1.53 or more and 1.85 or less, more preferably 1.55 or more and 1.75 or less, and most preferably 1.60 or more and 1.70 or less. As will be described in detail below, if the refractive index is too low, the difference in refractive index from the light scattering particles will be small, and conversely if the refractive index of the translucent resin is too high, the difference in refractive index from the light scattering particles will increase. It becomes difficult to design the light scattering property.

  In the present invention, the light scattering layer can have a high refractive index by dispersing oxide fine particles (low wavelength dispersibility) in the translucent resin. Thereby, the light-scattering film which satisfy | fills Numerical formula (3) is obtained. As means for adjusting the refractive index, the above-mentioned sulfur-containing resin or aromatic resin-containing high refractive index resin can be used in combination. Further, the oxide fine particles can be effectively dispersed in the light scattering layer by the action of the dispersant.

  The difference in refractive index between the translucent resin and the light scattering particles at wavelengths of 435 nm and 545 nm is preferably 0.02 or more and 0.20 or less. If the difference in refractive index is 0.02 or more, a satisfactory light scattering effect is obtained due to the difference in refractive index between the two, and if the difference in refractive index is 0.20 or less, the light scattering property is too high, and the film Overall whitening is suppressed. Here, the wavelengths of 435 nm and 545 nm are focused on the wavelengths corresponding to the primary colors of the additive color method, blue and green, and the wavelengths of the primary colors through the backlight typically used in liquid crystal display devices. It corresponds.

In equation (3), the value (K value) of (n _P435 / n _B435 ) / (n _P545 / n _B545 ) is the refractive index ratio between the particle at the blue light wavelength and the translucent resin, and the particle at the green light wavelength. This represents the relative relationship of the refractive index ratio between the transparent resin and the translucent resin, and is 1.0 if the refractive index ratio at both wavelengths is the same. The smaller the K value, the less blue light scatters with respect to green light. In the present invention, the K value needs to be less than 1.0, preferably 0.99 or less, and more preferably 0.98 or less. In particular, when the light-scattering particles are less than 3.0 μm, it is preferable that the blue light component tends to be larger than the green light component in the light scattering by the particles themselves, and the K value is preferably smaller than 1.0. On the other hand, when the K value is 0.9 or less, the scattering of blue light decreases, the scattered light becomes yellowish, and the color neutrality is lost.

  In particular, the contribution of scattered light becomes large in the TN mode and OCB mode with large luminance asymmetry, and this phenomenon becomes remarkable when observed from an oblique direction. In order to reduce the color change, the wavelength dispersibility of the refractive index of the translucent particles and the translucent resin can be brought close to each other to satisfy Equation (3).

[Means for Satisfying Equation (3)]
In order to satisfy Formula (3), it is preferable to use the following means (1) or means (2) alone or in combination.
Means (1): Increase the wavelength dispersibility of the light scattering particles and increase the refractive index of the short wavelength.
Means (2): The wavelength dispersibility of the translucent resin is decreased, and the refractive index of the short wavelength is decreased.
Hereinafter, each means will be described.

Means (1): A method for increasing the wavelength dispersion of the light scattering particles and increasing the refractive index of the short wavelength As means for increasing the refractive index of the light scattering particles, the compound constituting the light scattering particles is described above. This can be achieved by using a compound containing an aromatic ring.

Means (2): Method for reducing wavelength dispersibility of translucent resin and reducing refractive index of short wavelength In the present invention, means (2) is achieved by adding fine oxide particles. Therefore, in the present invention, the means (2) is an essential means, and the means (1) is an arbitrary means.

  In the present invention, as long as the light scattering particles and the translucent resin satisfy the above mathematical formulas (1) to (3), the above-described light scattering particles, the translucent resin, and the dispersant are used without particular limitation. Particularly preferred combinations are as follows.

Light scattering particles: acrylic-styrene copolymer resin particles Translucent resin: DPHA containing titanium oxide fine particles
The above combination is suitable for the present invention because the refractive index and K value can be controlled easily and inexpensively by appropriately adjusting the polymerization ratio of acrylic / styrene and the titanium oxide content.

[Formula (4)]
Spectral transmittance, which is a ratio at which a substance transmits without scattering / absorbing light, varies depending on the wavelength of light, and is usually measured as a spectral transmission spectrum. A light scattering layer in which light scattering particles are dispersed in a translucent resin has different spectral transmission spectra in the visible light region depending on the material, shape, and size of the particles. In the present invention, when the spectral transmittances at wavelengths of 435 nm and 545 nm are T ₄₃₅ and T ₅₄₅ , respectively, it is preferable to satisfy the following formula (4).
Formula (4): 0.33 < _T435 / _T545 <1.25

When the value (L value) of the above (T ₄₃₅ / T ₅₄₅ ) is small, there is much light scattering of the blue component, and the light transmitted vertically through the film may be yellowish to reddish. On the other hand, when the above value is large, there is little light scattering of the blue component, and the light transmitted vertically through the film may appear bluish. Therefore, in the light scattering film of the present invention, the L value is preferably in the range of 0.33 <L value <1.25, and more preferably in the range of 0.40 <L value <1.11. 0.66 <L value <1.00 is most preferable.

[Means for Satisfying Equation (4)]
As means for satisfying the mathematical formula (4), the above means (1) or (2) is used alone or in combination, and in addition to this, surface scattering due to irregularities on the surface of the light scattering film is imparted. Can also be achieved.

[Formula (5)]
In the present invention, it is preferable that the translucent resin has a small refractive index wavelength dispersibility, that is, satisfies the formula (5).
Formula (5): 1.005 <n _B435 / n _B545 <1.360
Here, when the evaluation value is 1.005 or less, the refractive index ratio between the light scattering particles and the translucent resin is increased in the short wavelength region, and the bluish change in transmitted light when the display device is mounted is increased. There is a case. On the other hand, when the evaluation value is 1.360 or more, the refractive index ratio between the two in the short wavelength region becomes small, and the redness change of the transmitted light may increase. Therefore, when the evaluation value is in the range of the above formula (5), a light scattering film having the highest visual improvement effect can be obtained.

  By satisfying Equation (5), the refractive index wavelength dispersibility of each of the translucent resin and the light scattering particles is lowered, and at the same time, the wavelength dependency of the refractive index ratio of both is also lowered. For this reason, the light-scattering characteristic for every wavelength approaches neutral, and the light-scattering film which controlled the tint change of the display apparatus optimally is obtained.

[Means for Satisfying Equation (5)]
A means for satisfying the mathematical expression (5) can be achieved by mixing an inorganic compound having a relatively small refractive index wavelength dispersion in the resin as compared with the organic compound. Specific examples include (1) a method of dispersing inorganic fine particles in a resin, (2) a method of using a resin containing sulfur atoms, and the like. (1) a method of dispersing inorganic fine particles in a resin. More preferable in terms of film strength control.

[Scattering effect by light scattering film]
In order to improve the display quality of the image display device (improve the viewing angle) with the light scattering film, it is necessary to appropriately diffuse the incident light. The greater the diffusion effect, the better the viewing angle characteristics. On the other hand, in order to maintain the front brightness in terms of display quality, it is necessary to increase the transmittance as much as possible.

  The moderate scattering property can be defined by a haze value. If the haze value is too low, a satisfactory viewing angle improvement effect cannot be obtained. On the other hand, if the haze value is too high, the front brightness decreases. Therefore, the haze value of the light scattering film is preferably 15% to 100%, more preferably 30% to 90%, and most preferably 50% to 85%. Therefore, in this invention, if a haze value is the range of 15 to 100%, it can be said that it has moderate scattering property.

[Relationship between layer thickness (d) of light scattering layer and average particle diameter (R) of light scattering particles]
In the light scattering layer of the present invention, it is preferable that the transmitted light is efficiently scattered by the light scattering particles. That is, the light scattering particles in the light scattering layer are preferably present in a state where they can be well dispersed and the transmitted light can be scattered in multiple ways.
Here, the relationship between the layer thickness (d) of the light scattering layer and the average particle diameter (R) of the light scattering particles is such that the d / R ratio is in the range of 1.4 to 4.0. Preferably they are 1.6 or more and 4.0 or less, More preferably, they are 2.0 or more and 4.0 or less. When the d / R ratio is small, the scattering effect by the light scattering particles is reduced and the desired scattering characteristics are not reached. If the d / R ratio is large, the scattering effect is too strong and the front contrast of the display device is lowered. By setting the d / R ratio in the above range, the frequency of multiple scattering in the light scattering layer can be increased, and the transmitted light can be efficiently scattered.

  The relationship between the layer thickness (d) of the light scattering layer and the average particle diameter (R) of the light scattering particles in the present invention will be described with reference to FIG. Here, FIGS. 1A to 1C are schematic views showing the relationship between the layer thickness (d) of the light scattering layer and the average particle diameter (R) of the light scattering particles.

  FIG. 1A shows a mode in which light scattering particles 2 (illustrated in a spherical shape) are included in a light scattering layer 1 (a layer indicated by a line). When the layer thickness is less than 1.4 times the particle size of the light scattering particles, the light scattering particles generally exist in one layer in the light scattering layer. Therefore, scattering by the light scattering particles occurs about once in the normal direction of the light scattering film.

On the other hand, when the layer thickness (R) of the light scattering layer is 1.4 to 4.0 times (thickening) the particle size (d) of the light scattering particles, the light scattering particles in the light scattering layer 1 Aggregation of 2 proceeds (see FIG. 1B). When the light scattering particles are aggregated, the scattering efficiency of the transmitted light is reduced and the desired scattering characteristics are not reached.
However, in the present invention, since the dispersant is added, it is possible to achieve both a thick film and an appropriate dispersion state, and as a result, desired scattering characteristics can be obtained when a display is mounted (FIG. 1). (See (c)). In this case, scattering by the light scattering particles 2 is expected to occur a plurality of times in the normal direction of the light scattering film. When the layer thickness (R) of the light scattering layer 1 is not less than 1.4 times and not more than 4.0 times the particle size (d) of the light scattering particle 2, light scattering is efficiently caused by multiple scattering of the light scattering particle 2. It becomes available.

  The layer thickness (R) is adjusted by the particle size (d) of the light scattering particles used. Specifically, the layer thickness (R) is preferably 6.0 to 15.0 μm, and 7 More preferably, it is 0.0-14.0 micrometers.

(Method for measuring film thickness and particle size)
The film thickness of the light scattering film can be measured by film cross-section observation using an optical microscope, a contact-type film thickness meter, or the like, but film cross-section observation using an optical microscope has less measurement error and is more preferable. Further, the particle diameter of the light scattering particles can be measured not only by observation with an optical microscope but also by using a scattering type particle size distribution measuring apparatus.

  In the present invention, the light-scattering film can be imparted with anti-glare properties by forming a slightly uneven shape on the film surface, as required. In order to obtain a clear surface for the purpose of maintaining the sharpness of the image, it is preferable that, for example, the center line average roughness (Ra) is 0.08 μm or less among the characteristics indicating the surface roughness. Ra is more preferably 0.07 μm or less, and still more preferably 0.06 μm or less.

(Coating solvent)
As a solvent used in the coating composition for forming each layer of the present invention, each component can be dissolved or dispersed, a uniform surface is easily formed in the coating process and the drying process, and liquid storage stability can be secured. Various solvents selected from the viewpoint of having an appropriate saturated vapor pressure can be used.

  Two or more kinds of solvents can be mixed and used. In particular, from the viewpoint of drying load, it is preferable that a solvent having a boiling point of 100 ° C. or lower at normal pressure and room temperature as a main component and a small amount of solvent having a boiling point of 100 ° C. or higher for adjusting the drying speed.

  Examples of the solvent having a boiling point of 100 ° C. or lower include hydrocarbons such as hexane (boiling point 68.7 ° C.), heptane (98.4 ° C.), cyclohexane (80.7 ° C.), and benzene (80.1 ° C.); Halogenated carbonization such as dichloromethane (39.8 ° C), chloroform (61.2 ° C), carbon tetrachloride (76.8 ° C), 1,2-dichloroethane (83.5 ° C), trichloroethylene (87.2 ° C) Hydrogen; ethers such as diethyl ether (34.6 ° C.), diisopropyl ether (68.5 ° C.), dipropyl ether (90.5 ° C.), tetrahydrofuran (66 ° C.); ethyl formate (54.2 ° C.), Esters such as methyl acetate (57.8 ° C), ethyl acetate (77.1 ° C), isopropyl acetate (89 ° C); acetone (56.1 ° C), 2-butanone (methyl ether) Ketones such as Luketone, 79.6 ° C; methanol (64.5 ° C), ethanol (78.3 ° C), 2-propanol (82.4 ° C), 1-propanol (97.2 ° C), etc. Alcohols; cyano compounds such as acetonitrile (81.6 ° C.) and propionitrile (97.4 ° C.); carbon disulfide (46.2 ° C.) and the like. Of these, ketones and esters are preferable, and ketones are particularly preferable. Among the ketones, 2-butanone is particularly preferable.

  Examples of the solvent having a boiling point of 100 ° C. or more include, for example, octane (125.7 ° C.), toluene (110.6 ° C.), xylene (138 ° C.), tetrachloroethylene (121.2 ° C.), and chlorobenzene (131.7 ° C.). , Dioxane (101.3 ° C), dibutyl ether (142.4 ° C), isobutyl acetate (118 ° C), cyclohexanone (155.7 ° C), 2-methyl-4-pentanone (same as MIBK, 115.9 ° C) 1-butanol (117.7 ° C.), N, N-dimethylformamide (153 ° C.), N, N-dimethylacetamide (166 ° C.), dimethyl sulfoxide (189 ° C.) and the like. Cyclohexanone and 2-methyl-4-pentanone are preferable.

[Method of forming light scattering layer]
The light scattering layer may be formed by any method as long as Expressions (1) to (3) are satisfied. As a forming method, it can be formed by the following coating method, but is not limited to this method. Dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method and extrusion coating method (die coating method) (see US Pat. No. 2,681,294), micro gravure coating method, etc. Known methods are used, and among them, the micro gravure coating method and the die coating method are preferable.

  The micro gravure coating method used in the present invention is a gravure roll having a diameter of about 10 to 100 mm, preferably about 20 to 50 mm and engraved with a gravure pattern on the entire circumference, below the support and in the transport direction of the support. The gravure roll is rotated in reverse with respect to the gravure roll, the excess coating liquid is scraped off from the surface of the gravure roll by a doctor blade, and a fixed amount of the coating liquid is removed from the support in a position where the upper surface of the support is in a free state. The coating method is characterized in that the coating liquid is transferred onto the lower surface for coating. A roll-shaped transparent support can be continuously unwound, and a light scattering layer can be applied to one side of the unwound support by a microgravure coating method.

  As coating conditions by the micro gravure coating method, the number of gravure patterns imprinted on the gravure roll is preferably 50 to 800 lines / inch, more preferably 100 to 300 lines / inch, and the depth of the gravure pattern is 1 to 600 μm. Is preferable, 5 to 200 μm is more preferable, the rotation speed of the gravure roll is preferably 3 to 800 rpm, more preferably 5 to 200 rpm, and the conveyance speed of the support is 0.5 to 100 m / min. It is preferably 1 to 50 m / min.

In order to supply the film of the present invention with high productivity, an extrusion method (die coating method) is preferably used. In particular, it can be preferably used in a region with a small amount of wet coating (20 cm ³ / m ² or less) such as a hard coat layer or an antireflection layer.

[Layer structure of light scattering film]
The constituent layers that can be added to the light scattering film of the present invention will be described below.
The light scattering film of the present invention can be provided with a necessary functional layer depending on the purpose in addition to the above-described light scattering layer.

  As a preferred embodiment, an antireflection layer laminated on a support having a light scattering layer in consideration of a refractive index, a film thickness, the number of layers, a layer order, etc. so that the reflectance is reduced by optical interference. Can be mentioned. In this specification, the antireflection layer is a general term for a high refractive index layer, a middle refractive index layer, and a low refractive index layer.

  In the simplest configuration, the antireflection layer has a configuration in which only a low refractive index layer is coated on a support having a light scattering layer. In order to further reduce the reflectance, the antireflection layer is preferably composed of a high refractive index layer having a higher refractive index than the light scattering layer and a low refractive index layer having a lower refractive index than the light scattering layer. . Examples of configurations include two layers of light scattering layer / high refractive index layer / low refractive index layer from the support side, or three layers having different refractive indexes, medium refractive index layer (support, light scattering layer or hard coat). A layer having a refractive index higher than that of the layer and a refractive index lower than that of the high refractive index layer) / high refractive index layer / low refractive index layer. Proposed. Above all, an antireflection layer is applied in the order of medium refractive index layer / high refractive index layer / low refractive index layer on a support having a hard coat layer and a light scattering layer in view of durability, optical characteristics, cost, productivity, etc. For example, the configurations described in JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706, etc. Can be mentioned.

  Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (for example, JP-A-10-206603, JP-A-2002). -243906 publication etc.) etc. are mentioned.

  Examples of preferred layer structures of the light scattering film having the antireflection layer of the present invention (hereinafter also referred to as antireflection light scattering film) are shown below. The antireflection light scattering film of the present invention is not particularly limited to these layer configurations as long as the reflectance can be reduced by optical interference. In this configuration, the light scattering layer can have an antiglare function.

Support film / light scattering layer / low refractive index layerSupport film / light scattering layer / antistatic layer / low refractive index layerSupport film / hard coat layer / light scattering layer / low refractive index layerSupport Film / hard coat layer / light scattering layer / antistatic layer / low refractive index layer Support film / hard coat layer / antistatic layer / light scattering layer / low refractive index layer Support film / light scattering layer / high refractive index Index layer / low refractive index layer-support film / light scattering layer / antistatic layer / high refractive index layer / low refractive index layer-support film / light scattering layer / medium refractive index layer / high refractive index layer / low refractive index Index layer-Support film / light scattering layer / high refractive index layer / low refractive index layer-Antistatic layer / support film / light scattering layer / medium refractive index layer / high refractive index layer / low refractive index layer Film / Antistatic layer / Light scattering layer / Medium refractive index layer / High refractive index layer / Low refractive index layer ・ Antistatic layer Support film / light scattering layer / medium refractive index layer / high refractive index layer / low refractive index layer Antistatic layer / support film / light scattering layer / high refractive index layer / low refractive index layer / high refractive index layer / Low refractive index layer

  Further, as another aspect, light scattering provided with layers necessary for the purpose of imparting hard coat properties, moisture resistance, gas barrier properties, antiglare properties, antifouling properties, etc. without actively using optical interference. Films are also preferred.

The example of the preferable layer structure of the film of the said aspect is shown below.
Support film / light scattering layer / hard coat layer Support film / light scattering layer Support film / light scattering layer / antiglare layer Support film / hard coat layer / light scattering layer Support film / light Scattering layer / hard coat layer-Support film / antistatic layer / light scattering layer-Support film / moisture-proof layer / light scattering layer-Support film / gas barrier layer / light scattering layer-Support film / light scattering layer / anti-reflection Antifouling layer ・ Antistatic layer / support film / light scattering layer ・ Light scattering layer / support film / antistatic layer

These layers can be formed by methods such as vapor deposition, atmospheric pressure plasma, and coating. From the viewpoint of productivity, it is preferably formed by coating.
Each constituent layer will be described below.

[Hard coat layer]
In order to impart the physical strength of the film to the film of the present invention, a hard coat layer can be preferably provided on one surface of the transparent support. The hard coat layer may be composed of two or more layers.

  The refractive index of the hard coat layer in the present invention is preferably in the range of 1.48 to 2.00 from the optical design for obtaining an antireflection light scattering film, more preferably 1. 52 to 1.90, more preferably 1.55 to 1.80. In an embodiment in which the low refractive index layer is at least one layer on the hard coat layer, which is a preferred embodiment of the present invention, the antireflective property is improved if the refractive index is not less than the lower limit of this range, and should be not more than the upper limit. If this is the case, the color of the reflected light will not become strong.

  From the viewpoint of imparting sufficient durability and impact resistance to the film, the thickness of the hard coat layer is usually about 0.5 μm to 50 μm, preferably 1 μm to 20 μm, more preferably 2 μm. 10 μm, most preferably 3 μm to 7 μm.

  Further, the surface strength of the hard coat layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test. Furthermore, in the Taber test according to JIS K-5400, the smaller the wear amount of the test piece before and after the test, the better.

  As in the case of the light scattering layer, the hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. For example, it may be formed by applying a coating composition containing an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer on a transparent support and subjecting the polyfunctional monomer or polyfunctional oligomer to a crosslinking reaction or a polymerization reaction. it can.

  The functional group of the ionizing radiation curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable. Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

  For the purpose of controlling the refractive index of the hard coat layer, a high refractive index monomer, inorganic particles, or both can be added to the binder of the hard coat layer. In addition to the effect of controlling the refractive index, the inorganic particles also have the effect of suppressing cure shrinkage due to the crosslinking reaction. In the present invention, after the hard coat layer is formed, a polymer formed by polymerizing the polyfunctional monomer and / or the high refractive index monomer and the like and the inorganic particles dispersed therein are referred to as a binder.

  On the other hand, when the antiglare function is imparted using surface scattering of the hard coat layer, the surface haze is preferably 5% to 15%, and more preferably 5% to 10%.

[Anti-glare layer]
The antiglare layer is formed for the purpose of contributing to the film an antiglare property due to surface scattering and preferably a hard coat property for improving the scratch resistance of the film.

  As a method of imparting antiglare properties, a method of laminating and forming a mat-shaped shaping film having fine irregularities on the surface as described in JP-A-6-16851; JP-A 2000-206317 As described, a method of forming by curing shrinkage of ionizing radiation curable resin due to a difference in ionizing radiation dose; weight ratio of good solvent to translucent resin by drying as described in JP-A-2000-338310 Is a method of forming unevenness on the coating film surface by gelling the translucent fine particles and the translucent resin while gelling; as described in JP-A-2000-275404, Method for imparting surface irregularities; Method for imparting surface irregularities by external pressure as described in JP 2000-275404 A; JP 2005-195819 A As described in the report, a method of forming surface irregularities by utilizing phase separation in the process of evaporation of a solvent from a mixed solution of a plurality of polymers is known, and these known methods can be used. it can.

[High refractive index layer, medium refractive index layer]
When the light scattering film of the present invention is provided with a high refractive index layer and a medium refractive index layer and optical interference is used together with a low refractive index layer described later, the antireflection property can be enhanced.

  In the following specification, the high refractive index layer and the middle refractive index layer may be collectively referred to as a high refractive index layer. In the present invention, “high”, “medium”, and “low” in the high refractive index layer, medium refractive index layer, and low refractive index layer represent the relative refractive index relationship between the layers. In terms of the relationship with the transparent support, the refractive index preferably satisfies the relationship of transparent support> low refractive index layer, high refractive index layer> transparent support.

  In order to construct a low refractive index layer on a high refractive index layer and produce an antireflection light scattering film, the refractive index of the high refractive index layer is preferably 1.55 to 2.40, More preferably, it is 1.60-2.20, More preferably, it is 1.65-2.10, Most preferably, it is 1.80-2.00.

  When an antireflective light scattering film is prepared by coating a medium refractive index layer, a high refractive index layer, and a low refractive index layer in order from the support, the refractive index of the high refractive index layer is 1.65 to 2. 40 is preferable, and 1.70 to 2.20 is more preferable. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55-1.80.

  The medium refractive index layer and the high refractive index layer are coated with inorganic particles for increasing the refractive index of the layer to be formed, a binder and a solvent for forming a matrix, and a polymerization initiator according to necessity. It is preferably formed by applying the composition and drying the solvent, followed by curing by heating, irradiation with ionizing radiation, or a combination of both means. When a curable resin or an initiator is used, the medium refractive index layer or the high refractive index layer can be formed by curing the curable resin by a polymerization reaction by heat / ionizing radiation after coating.

Specific examples of the inorganic particles used in the high refractive index layer and the medium refractive index layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO _2. Etc. TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index. The surface of the inorganic particles is preferably subjected to silane coupling treatment or titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.

  Since the medium refractive index layer can be similarly adjusted using the same material except that the refractive index is different from that of the high refractive index layer, the high refractive index layer will be particularly described below.

  The content of the inorganic particles in the high refractive index layer is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and particularly preferably 15 to 75% by mass with respect to the mass of the high refractive index layer. . Two or more kinds of inorganic particles may be used in combination in the high refractive index layer.

  In the present invention, in order to increase the refractive index of the high refractive index layer, in addition to using high refractive index inorganic particles, an ionizing radiation curable compound containing an aromatic ring, a halogenated element other than fluorine (for example, A binder obtained by a crosslinking or polymerization reaction such as an ionizing radiation curable compound containing Br, I, Cl or the like, or an ionizing radiation curable compound containing atoms such as S, N or P can also be preferably used.

  When the low refractive index layer is provided on the high refractive index layer, the refractive index of the high refractive index layer is preferably higher than the refractive index of the transparent support.

  The film thickness of the high refractive index layer can be appropriately designed depending on the application. When using a high refractive index layer as an optical interference layer described later, the thickness is preferably 30 to 200 nm, more preferably 50 to 170 nm, and particularly preferably 60 to 150 nm.

  The haze of the high refractive index layer is preferably as low as possible when it does not contain particles that impart an antiglare function. It is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. The high refractive index layer is preferably constructed directly on the transparent support or via another layer.

[Low refractive index layer]
In order to reduce the reflectance of the film of the present invention, it is preferable to use a low refractive index layer.

  The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.40.

  The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm.

  The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less.

  The specific surface strength of the low refractive index layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test under a 500 g load.

  Moreover, in order to improve the antifouling performance of the light scattering film of the present invention, it is preferable that the contact angle of the surface with respect to water is 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

  The low refractive index layer is preferably formed using a cured product that is cured by heating, ionizing radiation irradiation, or a combination of both means. When a curable resin or an initiator is used, the low refractive index layer can be formed by curing the curable resin by a polymerization reaction using heat and / or ionizing radiation after coating.

As an aspect of a preferable cured product composition,
(1) A composition containing a fluorine-containing polymer having a crosslinkable or polymerizable functional group,
(2) a composition comprising as a main component a hydrolysis-condensation product of a fluorine-containing organosilane compound,
(3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure;
Etc.

(1) Composition containing a fluorine-containing polymer having a crosslinkable or polymerizable functional group As the fluorine-containing polymer having a crosslinkable or polymerizable functional group, a fluorine-containing monomer and a crosslinkable or polymerizable functional group And a copolymer with a monomer having. Examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.), (meth) Partially or fully fluorinated alkyl ester derivatives of acrylic acid {eg, “Biscoat 6FM”, manufactured by Osaka Organic Chemical Industry Co., Ltd., “M-2020”, manufactured by Daikin Industries, Ltd., etc.}, fully or partially fluorinated vinyl ether Etc.

  As a monomer for providing a crosslinkable group, as one embodiment, a (meth) acrylate monomer having a crosslinkable functional group in the molecule in advance, such as glycidyl methacrylate, can be exemplified. Another embodiment is a method of using a monomer that introduces a crosslinkable or polymerizable functional group by modifying a substituent after synthesizing a fluorine-containing polymer using a monomer having a functional group such as a hydroxyl group. . These monomers include (meth) acrylate monomers having a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc. {for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.} Is mentioned. The latter embodiment is disclosed in Japanese Patent Laid-Open Nos. 10-25388 and 10-147739.

  From the viewpoints of solubility, dispersibility, coatability, antifouling property, antistatic property and the like, the above-mentioned fluoropolymer can contain components that can be suitably copolymerized. In particular, for imparting antifouling properties and slipperiness, it is preferable to introduce silicone, and it can be introduced into both the main chain and the side chain.

  The polysiloxane partial structure introduction method to the main chain is, for example, an azo group-containing polysiloxane amide described in JP-A-6-93100 {in the commercially available products, “VPS-0501”, “VPS-1001” (trade name), And a method using a polymer type initiator such as Wako Pure Chemical Industries, Ltd.}. Moreover, the method of introduce | transducing into a side chain is "J.Appl.Polym.Sci.", 2000 volumes, p. 78, 1955, as described in JP-A-56-28219, etc., polysiloxanes having a reactive group at one end {for example, “Silaplane” series, manufactured by Chisso Corporation, etc.} are introduced by polymer reaction. And a method of polymerizing a polysiloxane-containing silicon macromer, and both methods can be preferably used.

  As described in JP-A-2000-17028, a curing agent having a polymerizable unsaturated group may be used in combination with the above polymer. In addition, as described in JP-A No. 2002-145952, combined use with a compound having a fluorine-containing polyfunctional polymerizable unsaturated group is also preferable. Examples of the compound having a polyfunctional polymerizable unsaturated group include the above-described monomers having two or more ethylenically unsaturated groups. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane which has a (meth) acryloyl group is especially preferable. These compounds are particularly preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

  Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

(2) Composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane compound The composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane compound also has a low refractive index and has a coating surface hardness. Highly preferred. A condensate of tetraalkoxysilane with a compound having a hydrolyzable silanol group at one or both ends with respect to the fluorinated alkyl group is preferred. Specific compositions are described in JP-A No. 2002-265866 and JP-A-317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure As yet another preferred embodiment, a low refractive index layer comprising low refractive index particles and a binder can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. Specific examples of the hollow particles are described in the silica-based particles described in JP-A-2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the binder include monomers having two or more ethylenically unsaturated groups described in the page of the light diffusion layer.

  In the preferred embodiment of the present invention, it is preferable to add the polymerization initiator described in the section of the light scattering layer to the low refractive index layer. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the compound.

  In the low refractive layer in the present invention, inorganic particles can be used in combination. In order to impart scratch resistance, fine particles having a particle size of 15% to 150%, preferably 30% to 100%, more preferably 45% to 60% of the thickness of the low refractive index layer can be used. .

  For the purpose of imparting antifouling properties, water resistance, chemical resistance, slipping properties and the like, the low refractive index layer in the present invention is appropriately added with known polysiloxane-based or fluorine-based antifouling agents, slipping agents, etc. Can be added.

[Antistatic layer]
In the present invention, it is preferable to provide an antistatic layer from the viewpoint of preventing static electricity on the film surface. The antistatic layer can be formed by, for example, applying a conductive coating solution containing conductive fine particles and a reactive curable resin, or depositing or sputtering a metal or metal oxide that forms a transparent film. Conventionally known methods such as a method of forming a conductive thin film can be listed. The antistatic layer can be formed directly on the support or via a primer layer that strengthens adhesion to the support. The antistatic layer can also be used as a part of the antireflection layer. In this case, when used in a layer close to the outermost layer, sufficient antistatic properties can be obtained even if the antistatic layer is thin.

The thickness of the antistatic layer is preferably from 0.01 to 10 μm, more preferably from 0.03 to 7 μm, and even more preferably from 0.05 to 5 μm. The surface resistance of the antistatic layer is preferably from 10 ⁵ ~10 ¹² Ω / sq, more preferably from 10 ⁵ ~10 ⁹ Ω / sq, most be 10 ⁵ ~10 ⁸ Ω / sq preferable. The surface resistance of the antistatic layer can be measured by a four probe method.

  The antistatic layer is preferably substantially transparent. Specifically, the haze of the antistatic layer is preferably 10% or less, more preferably 5% or less, further preferably 3% or less, and most preferably 1% or less. The transmittance of light having a wavelength of 550 nm is preferably 50% or more, more preferably 60% or more, further preferably 65% or more, and most preferably 70% or more.

  The antistatic layer in the present invention preferably has excellent surface strength, and the specific surface strength of the antistatic layer is preferably H or higher, preferably 2H or higher, with a pencil hardness of 1 kg load. More preferably, it is more preferably 3H or more, and most preferably 4H or more.

[Coating solvent]
Among the above constituent layers, the layer applied adjacent to the support contains at least one solvent that dissolves the support film and at least one solvent that does not dissolve the support film. Is preferred. By setting it as such an aspect, coexistence with the prevention of the excessive penetration | infiltration of the adjacent layer component to a support body film and ensuring adhesiveness of an adjacent layer and a support body film can be aimed at. Moreover, it is more preferable that at least one of the solvents that dissolve the support film has a higher boiling point than at least one of the solvents that do not dissolve the support film. More preferably, the boiling point temperature difference between the solvent having the highest boiling point among the solvents that dissolve the support film and the solvent having the highest boiling point among the solvents that do not dissolve the support film is 30 ° C. or more, Most preferably, it is 40 degreeC or more.

  The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the support film and the total amount (B) of the solvent that does not dissolve the transparent support film is preferably 5/95 to 50/50, more preferably 10 / 90 to 40/60, more preferably 15/85 to 30/70.

[Support]
The support for the light scattering film of the present invention is not particularly limited, such as a transparent resin film, a transparent resin plate, a transparent resin sheet, and transparent glass. Transparent resin films include cellulose acylate films (for example, cellulose triacetate film (refractive index 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyethylene terephthalate film, polyethersulfone. Film, polyacrylic resin film, polyurethane resin film, polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyetherketone film, (meth) acrylonitrile film polyolefin, alicyclic structure Polymer [Norbornene resin {"ARTON" (trade name), manufactured by JSR Corporation}, amorphous polyolefin {" Onex "(trade name), manufactured by Nippon Zeon (Ltd.)}], and the like. Of these, triacetyl cellulose, polyethylene terephthalate, and polymers having an alicyclic structure are preferable, and triacetyl cellulose is particularly preferable.

  Although the thickness of a support body can be normally referred to as about 25 micrometers-1000 micrometers, Preferably it is 25 micrometers-250 micrometers, and it is more preferable that they are 30 micrometers-90 micrometers.

  Any width of the support can be used, but from the viewpoint of handling, yield, and productivity, a thickness of 100 to 5000 mm is usually used, preferably 800 to 3000 mm, preferably 1000 to 2000 mm. More preferably it is. The support can be handled in the form of a roll, and is usually 100 m to 5000 m, preferably 500 m to 3000 m.

  The surface of the support is preferably smooth, and the average roughness Ra is preferably 1 μm or less, preferably 0.0001 to 0.5 μm, and 0.001 to 0.1 μm. Is more preferable.

[Cellulose acylate film]
Among the various films described above, a cellulose acylate film having high transparency, optically low birefringence, easy production and generally used as a protective film for a polarizing plate is preferred as a support.

  For cellulose acylate films, various improvement techniques are known for the purpose of improving mechanical properties, transparency, flatness, etc., and the techniques described in the published technical reports 2001-1745 are known as known ones. It can be used for the film of the invention.

<Application of light scattering film>
〔Polarizer〕
The polarizing plate of the present invention is a polarizing plate having a polarizing film and protective films on both sides of the polarizing film, wherein at least one protective film is the above-described light scattering film of the present invention.
That is, the light scattering film of the present invention can be used as a protective film disposed on one side or both sides of a polarizing film, and can be used as a polarizing plate. As one protective film, the light scattering film of the present invention is used, and the other protective film may be a normal cellulose acetate film, but is manufactured by a solution casting method and has a stretch ratio of 10 to 100%. It is preferable to use a cellulose acetate film stretched in the width direction in the form of a roll film.

  Furthermore, in the polarizing plate of the present invention, it is preferable that one side is the light scattering film of the present invention, whereas the other protective film is an optical compensation film having an optically anisotropic layer made of a liquid crystalline compound. . The optical compensation film (retardation film) can improve the viewing angle characteristics of the liquid crystal display screen. A known film can be used as the optical compensation film, but the optical compensation film described in JP-A-2001-100042 is preferable in terms of widening the viewing angle.

  Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.

  The slow axis of the support of the light scattering film or the cellulose acetate film and the transmission axis of the polarizing film are arranged so as to be substantially parallel.

  The moisture permeability of the protective film is important for the productivity of the polarizing plate. The polarizing film and the protective film are bonded together with an aqueous adhesive, and the adhesive solvent is dried by diffusing in the protective film. The higher the moisture permeability of the protective film, the faster the drying and the higher the productivity. However, if the protective film is too high, moisture will enter the polarizing film depending on the usage environment (high humidity) of the liquid crystal display device. Polarization ability decreases.

The moisture permeability of the protective film is determined by the thickness, free volume, hydrophilicity / hydrophobicity, etc. of the support or polymer film (and polymerizable liquid crystal compound). When using the film of the present invention as a protective film of a polarizing plate, the moisture permeability is preferably from 100~1000g / m ² · 24hrs, and more preferably a 300~700g / m ² · 24hrs.

  As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used. A long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction is produced by the following method.

  That is, with a polarizing film stretched by applying tension while holding both ends of a continuously supplied polymer film by a holding means, stretched at least 1.1 to 20.0 times in the film width direction, The progress of the film is such that the difference between the moving speeds in the longitudinal direction of the holding device is within 3%, and the angle formed between the moving direction of the film at the exit of the process of holding both ends of the film and the substantial stretching direction of the film is inclined by 20 to 70 °. It can be produced by a stretching method in which the direction is bent while holding both ends of the film. In particular, those inclined by 45 ° are preferably used from the viewpoint of productivity.

[Liquid Crystal Display]
The image display device of the present invention has the light scattering film of the present invention described above or the polarizing plate of the present invention.
The liquid crystal display device of the present invention is a liquid crystal display device having a TN mode or OCB mode liquid crystal cell, and has the above-described light scattering film of the present invention or the polarizing plate of the present invention.
That is, the light diffusion film and / or polarizing plate of the present invention can be advantageously used for an image display device such as a liquid crystal display device, and is preferably used for the outermost layer of the display.

  The liquid crystal display device has a liquid crystal cell and two polarizing plates arranged on both sides thereof, and the liquid crystal cell carries a liquid crystal between two electrode substrates. Furthermore, one optically anisotropic layer may be disposed between the liquid crystal cell and one polarizing plate, or two optically anisotropic layers may be disposed between the liquid crystal cell and both polarizing plates.

  The liquid crystal cell has a TN mode, a VA mode, an OCB mode, an IPS mode, or an ECB mode. As described above, the effect of improving the viewing angle characteristics using the light scattering film of the present invention is large. It is.

[TN mode]
In the TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are twisted and aligned at 60 to 120 °. The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents.

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

  The configuration of the OCB mode liquid crystal display device, the optically anisotropic layer, the cellulose protective film, the polarizing film, the color filter and the like that can be used are described in detail in JP-A-2006-259003.

  In recent years, liquid crystal display devices tend to be large. With the increase in size, the effect of the viewing angle characteristics of the liquid crystal display device on the comfort felt by the user is increasing. Accordingly, since the viewing angle asymmetry of the TN mode or OCB mode liquid crystal display device is improved by mounting the light scattering film, the light scattering film of the present invention is used particularly for a large display device of 26 inches or more. Is desirable.

(Effect of light scattering film on OCB mode and TN mode)
The light scattering film of the present invention is preferably used for the OCB mode and the TN mode. The OCB mode is a display mode that improves the response speed among liquid crystal displays. On the other hand, the OCB mode liquid crystal display device is inferior in viewing angle luminance asymmetry in a 45-degree oblique direction due to the liquid crystal alignment, as compared with other liquid crystal display modes. The light-scattering film in the present invention scatters the transmitted light of the display isotropically and uniformly scatters the color component to the peripheral angle, so that it is possible to reduce the viewing angle luminance asymmetry without changing the color tone. It is.
In addition, the TN mode is a liquid crystal display mode developed in the early stage, which is low in cost, but the gradation inversion in the vertical direction is a big problem. A viewing angle compensation film is generally mounted as a method for reducing gradation inversion (for example, Japanese Patent Application Laid-Open No. 2004-233872). However, in order to supplement the effect of the viewing angle compensation film, It is more effective to use the characteristics of

(Effect of light scattering film for large display devices)
The light scattering film of the present invention is preferably used for a liquid crystal display device having a panel size of 26 inches or more. When the enlarged display device is used at the same distance as when a conventional display device is used, the viewing angle region in the left-right direction for looking over the range from end to end of the screen increases. For this reason, the visual asymmetry of the display device is more conspicuous than the conventional display device when a large display device is used.

  In addition, the display device installation methods have been diversified with the increase in size and thickness of displays. Therefore, there is a need for further improvement in the viewing angle asymmetry not only in the left-right direction but also in the vertical direction. In particular, in the OCB mode and TN mode liquid crystal display devices, the problem of viewing angle luminance asymmetry as described above is more conspicuous as compared with other liquid crystal display modes. The light-scattering film in the present invention is capable of reducing the viewing angle luminance asymmetry without being accompanied by a change in color tone by isotropically diffusing the transmitted light of the display and scattering the color component equally to the peripheral angle. Therefore, it is suitably used for the large display device as described above. The light scattering film in the present invention is preferably used for a liquid crystal display device having a panel size of 26 inches or more, more preferably used for a liquid crystal display device of 32 inches or more, and a liquid crystal display having a size of 37 inches or more. More preferably, it is used for an apparatus.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, “parts” and% are based on mass.

[Preparation of coating solution for each layer]
[Preparation of coating solution for light scattering layer]
{Preparation of titanium dioxide dispersion (T1)}
As titanium dioxide fine particles, titanium dioxide fine particles (MPT-129C, manufactured by Ishihara Sangyo Co., Ltd.) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide were used. The following dispersant (38.6 parts by mass) and cyclohexanone (704.3 parts by mass) were added to 257.1 parts by mass of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

{Preparation of titanium dioxide dispersion (T2)}
A titanium dioxide dispersion (T2) was obtained in exactly the same manner except that the dispersant was removed from the titanium dioxide dispersion (T1).

{Preparation of coating solution for light scattering layer (DL-1)}
Titanium dioxide fine particle dispersion (T1) 100 parts by mass, dipentaerythritol hexaacrylate {manufactured by Nippon Kayaku Co., Ltd.} 66 parts by mass, acrylic-styrene copolymer resin particles “SX-350HL” having a particle size of 3.5 μm {Soken Chemical Co., Ltd.} 10 parts by mass, polymerization initiator “Irgacure 907” 3.5 parts by mass {manufactured by Ciba Geigy}, photosensitizer Kayacure DETX 1.2 parts by mass (manufactured by Nippon Kayaku Co., Ltd.), the following Mix 3 parts by weight of the dispersant, adjust the solid content to 50% with methyl ethyl ketone / cyclohexanone (20/80 mass ratio), put into a mixing tank, stir, and then filter through a polypropylene filter with a pore size of 0.4 μm. Then, a coating solution for light scattering layer (DL-1) was prepared.

{Preparation of coating solution for light scattering layer (DL-2)}
In the preparation of the coating solution for light scattering layer (DL-1), the light scattering particle was changed except that the light scattering particles were changed to polymethylmethacrylate resin particles “MX-300” {manufactured by Soken Chemical Co., Ltd.} having a particle size of 3.0 μm. In the same manner as the preparation of the scattering layer coating liquid (DL-1), a light scattering layer coating liquid (DL-2) was prepared.

{Preparation of coating solution for light scattering layer (DL-3)}
Titanium dioxide fine particle dispersion (T2) 100 parts by mass, dipentaerythritol hexaacrylate {manufactured by Nippon Kayaku Co., Ltd.} 66 parts by mass, acrylic-styrene copolymer resin particle “SX-350HL” having a particle size of 3.5 μm {Soken Chemical Co., Ltd.} 10 parts by mass, polymerization initiator “Irgacure 907” 3.5 parts by mass {Ciba Geigy Co., Ltd.}, photosensitizer Kayacure DETX 1.2 parts by mass (manufactured by Nippon Kayaku Co., Ltd.) Then, the solid content is adjusted to 50% with methyl ethyl ketone / cyclohexanone (20/80 mass ratio), put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 30 μm to obtain a coating solution for light scattering layer (DL-3) was prepared.

{Preparation of coating solution for light scattering layer (DL-4)}
In the preparation of the light scattering layer coating liquid (DL-1), except that the titanium dioxide fine particle dispersion (T1) was changed to 70 parts by mass, the same as the preparation of the light scattering layer coating liquid (DL-1), A coating solution for light scattering layer (DL-4) was prepared.

{Preparation of coating solution for light scattering layer (DL-5)}
Dipentaerythritol hexaacrylate {manufactured by Nippon Kayaku Co., Ltd.} 91 parts by mass, polymethyl methacrylate resin particle “MX-300” having a particle size of 3.0 μm {manufactured by Soken Chemical Co., Ltd.} 10 parts by mass, polymerization initiator “ "Irgacure 907" 3.5 parts by mass {manufactured by Ciba-Geigy}, 1.2 parts by mass of photosensitizer Kayacure DETX (manufactured by Nippon Kayaku Co., Ltd.), and 3 parts by mass of the following dispersant were mixed, and methyl ethyl ketone / cyclohexanone (20 / 80 mass ratio), the solid content is adjusted to 50%, charged into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 30 μm to prepare a light scattering layer coating solution (DL-5). did.

[Preparation of coating solution for low refractive index layer]
(Preparation of sol solution s)
To a reactor equipped with a stirrer and a reflux condenser, add 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane “KBM-5103” {manufactured by Shin-Etsu Chemical Co., Ltd.}, and 3 parts of diisopropoxyaluminum ethyl acetoacetate After mixing, 30 parts of ion exchange water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain a sol solution s. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Preparation of hollow silica dispersion S)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica particle refractive index 1.31, change size according to Preparation Example 4 of JP 2002-79616 A And 30 parts by mass of “KBM-5103” (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.5 parts by mass of diisopropoxyaluminum ethyl acetate, and 500 parts by mass. Part was added. After making it react at 60 degreeC for 8 hours, it cooled to room temperature and added 1.8 mass parts of acetylacetone. Solvent substitution by vacuum distillation was performed while adding cyclohexanone to 500 parts by mass of this dispersion so that the silica content was substantially constant. No foreign matter was generated in the dispersion, and the solid content was adjusted to 20% by mass with cyclohexanone. In this way, a hollow silica dispersion S was prepared.

{Preparation of coating solution for low refractive index layer (Ln-1)}
Ethylenically unsaturated group-containing fluorine-containing polymer {Fluoropolymer (A-1) described in Production Example 3 of JP-A-2005-89536)} 45.0 parts by mass as a solid content is dissolved in 500 parts by mass of methyl isobutyl ketone, Furthermore, 195 parts by mass of hollow silica dispersion S (39.0 parts by mass as silica + surface treatment agent solid content), colloidal silica dispersion {silica, “MEK-ST” having a different particle diameter, average particle diameter of 45 nm, Solid content concentration 30% by mass, manufactured by Nissan Chemical Co., Ltd.} 30.0 parts by mass (9.0 parts by mass as solids), 17.0 parts by mass of sol liquid s (5.0 parts by mass as solids), light Polymerization initiator “PM980M” {manufactured by Wako Pure Chemical Industries, Ltd.} 2.0 parts by mass was added. The coating solution for low refractive index (Ln-1) was prepared by diluting with methyl ethyl ketone so that the solid content concentration of the entire coating solution was 6% by mass.

<Example 1>
[Production of light scattering film]
{Preparation of light scattering film (101)}
As a support, on the triacetyl cellulose film “TD-80U” {manufactured by FUJIFILM Corporation}, a light scattering layer coating solution (DL-1) is applied to a dry film thickness of 7.0 μm. After drying, using an “air-cooled metal halide lamp” {manufactured by Eye Graphics Co., Ltd.} of 160 W / cm, the coating layer is cured by irradiating with ultraviolet light having an illuminance of 1.5 kW / cm ² and an irradiation amount of 95 mJ / cm ^2. A light scattering film (101) was produced.

Preparation of {Light Scattering Film (102)} In the preparation of the light scattering film (101), light scattering was performed except that the coating liquid for light scattering layer (DL-1) was applied so that the dry film thickness was 14.0 μm. A light scattering film (102) was produced in the same manner as the production of the film (101).

Preparation of {Light Scattering Film (103)} In the preparation of the light scattering film (101), the light scattering was performed except that the coating liquid for light scattering layer (DL-1) was applied so that the dry film thickness was 18.0 μm. A light scattering film (103) was produced in the same manner as the production of the film (101).

Preparation of {Light Scattering Film (104)} In the preparation of the light scattering film (101), light scattering was performed except that the coating liquid for light scattering layer (DL-1) was applied so that the dry film thickness was 4.0 μm. A light scattering film (104) was produced in the same manner as the production of the film (101).

Preparation of {light scattering film (105)} In the preparation of the light scattering film (101), a light scattering layer coating liquid (DL-2) is used in place of the light scattering layer coating liquid (DL-1). Produced a light scattering film (105) in the same manner as the light scattering film (101).

Preparation of {light scattering film (106)} In the preparation of the light scattering film (101), a coating liquid for light scattering layer (DL-3) is used instead of the coating liquid for light scattering layer (DL-1). Produced a light scattering film (106) in the same manner as the light scattering film (101).

Preparation of {light scattering film (107)} In preparation of the light scattering film (101), a coating liquid for light scattering layer (DL-4) is used instead of the coating liquid for light scattering layer (DL-1). Produced a light scattering film (107) in the same manner as the light scattering film (101).

Preparation of {light scattering film (108)} In preparation of the light scattering film (101), a coating liquid for light scattering layer (DL-5) is used instead of the coating liquid for light scattering layer (DL-1). Produced a light scattering film (108) in the same manner as the light scattering film (101).

[Production of liquid crystal display device and polarizing plate used therefor]
[Preparation of polarizing plate]
{Preparation of optical compensation film}
(Preparation of cellulose acetate solution)
80 parts by mass of cellulose acetate (linter) with an acetylation degree of 60.9%, 20 parts by mass of cellulose acetate (linter) with an acetylation degree of 60.8%, 7.8 parts by mass of triphenyl phosphate, 3.9 parts by mass of biphenyl diphenyl phosphate Part, 300 parts by mass of methylene chloride, and 45 parts by mass of methanol were put in this order in a mixing tank, and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

(Preparation of retardation increasing agent solution)
4 parts by mass of cellulose acetate (linter) having an acetylation degree of 60.9%, 25 parts by mass of the following retardation increasing agent, 0.5 parts by mass of silica fine particles (average particle size: 20 nm), 80 parts by mass of methylene chloride, 20 parts by mass of methanol The portions were stirred while being heated in another mixing tank in this order to prepare a retardation increasing agent solution.

(Preparation of cellulose acetate film A)
30 parts by mass of the above-mentioned retardation increasing agent solution was mixed with 470 parts by mass of the cellulose acetate solution, and the dope was prepared by sufficiently stirring. The addition amount of the retardation increasing agent was 6.2 parts by mass with respect to 100 parts by mass of cellulose acetate.

  The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 35 ° C., it was dried for 1 minute, and after peeling off when the residual solvent amount was 45% by mass, it was 28% in the width direction in a tenter stretching zone under a temperature atmosphere of 140 ° C. After stretching, it was dried at 140 ° C. for 10 minutes and at 130 ° C. for 20 minutes to produce a cellulose acetate film (thickness 60 μm) having a residual solvent amount of 0.3 mass%.

  As a result of measuring the optical properties of the produced cellulose acetate film, the Re retardation value was 35 nm and the Rth retardation value was 175 nm. The optical properties were measured for Re retardation value and Rth retardation value at a wavelength of 550 nm using “Ellipsometer M150” (manufactured by JASCO Corporation).

A 1.5N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 14/86/15% by volume) was applied to the surface of the produced cellulose acetate film at 5 mL / m ² and held at 60 ° C. for 10 seconds. Thereafter, potassium hydroxide remaining on the film surface was washed with water and dried. The surface energy of the cellulose acetate film was determined by a contact angle method and found to be 60 mN / m. Thus, a cellulose acetate film A for an optical compensation film that also serves as a protective film in the polarizing plate was produced.

(Formation of optically anisotropic layer)
(Preparation of coating solution for alignment film)
The following modified polyvinyl alcohol, 10 parts by weight, 371 parts by weight of water, 119 parts by weight of methanol, and 0.5 parts by weight of glutaraldehyde were mixed in this order to prepare a coating solution for an alignment film.

(Formation of alignment film)
On the cellulose acetate film A, 28 mL / m ² of the alignment film coating solution was applied with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds. Next, a rubbing treatment was performed on the formed film in a direction formed 45 with the longitudinal direction of the cellulose acetate film A. In this way, an alignment film was coated thereon using the cellulose acetate film A as a support.

(Preparation of coating solution for optical anisotropic layer)
102 parts by mass of methyl ethyl ketone, 41.01 parts by mass of the following discotic liquid crystalline compound, ethylene oxide-modified trimethylolpropane triacrylate “V360” {manufactured by Osaka Organic Chemical Industry Co., Ltd.} 4.06 parts by mass, cellulose acetate butyrate “CAB551 -0.2 "{Eastman Chemical Co., Ltd.} 0.68 parts by mass, photopolymerization initiator" Irgacure 907 "{Ciba Specialty Chemicals Co., Ltd.} 1.35 parts by mass, photosensitizer" 0.45 parts by mass of “Kayacure DETX” {manufactured by Nippon Kayaku Co., Ltd.} was mixed in this order to prepare a coating solution for an optically anisotropic layer.

(Coating of optical anisotropic layer)
The optical anisotropic layer coating solution was applied onto the alignment film with a # 4 wire bar. This was heated in a constant temperature zone of 130 ° C. for 2 minutes to hybridize the discotic liquid crystalline compound. Next, ultraviolet rays were irradiated for 0.4 seconds using a 1200 Wcm high-pressure mercury lamp in an atmosphere of 100 ° C., and the alignment was fixed by polymerizing the discotic liquid crystalline compound. In this way, an optically anisotropic layer was applied to the cellulose acetate film A to form an optical compensation film.

[Preparation of viewing side polarizing plate for OCB mode]
{Preparation of OCB mode viewing side polarizing plate (Pol-1)}
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. After saponifying the back surface of the light scattering film (101) (the surface opposite to the surface on which the light scattering layer is formed), using a polyvinyl alcohol adhesive, the back surface of the light scattering film is on the polarizing film side. Affixed to one side of the polarizing film.

  Furthermore, the optical compensation film prepared by coating the optically anisotropic layer as described above is obtained by using a polyvinyl alcohol adhesive so that the cellulose acetate film A is on the polarizing film side. It was affixed to the side opposite to the side where (101) was affixed. The transmission axis of the polarizing film and the slow axis of the cellulose acetate film A of the optical compensation film were arranged in parallel. In this way, an OCB mode viewing side polarizing plate (Pol-1) was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-2)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (102) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing-side polarizing plate (Pol-2) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-3)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (103) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing-side polarizing plate (Pol-3) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-4)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (104) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing-side polarizing plate (Pol-4) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-5)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (105) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing side polarizing plate (Pol-5) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-6)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (106) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing-side polarizing plate (Pol-6) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-7)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (107) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing side polarizing plate (Pol-7) for OCB mode was produced.

{Preparation of OCB mode viewing side polarizing plate (Pol-8)}
In the production of the viewing side polarizing plate (Pol-1), it is the same as the polarizing plate (Pol-1) except that the light scattering film (108) is used instead of the light scattering film (101) as the protective film on one side. Thus, a viewing-side polarizing plate (Pol-8) for OCB mode was produced.

[Preparation of backlight-side polarizing plate]
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. The optical compensation film prepared by coating the optically anisotropic layer as described above was attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive so that the cellulose acetate film A was on the polarizing film side. The transmission axis of the polarizing film and the slow axis of the cellulose triacetate film A of the optical compensation film were arranged so as to be parallel. Further, a commercially available cellulose triacetate film “TD80-UF” {manufactured by FUJIFILM Corporation} was subjected to saponification treatment and attached to the side of the polarizing film opposite to the side where the optical compensation film was attached. In this way, a backlight side polarizing plate was produced.

[Production of liquid crystal display device]
[Production of OCB Mode Liquid Crystal Display Device (201)]
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The obtained two glass substrates were opposed to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 6 μm. A liquid crystal compound “ZLI1132” (manufactured by Merck & Co., Inc.) having an Δn of 0.1396 was injected into the cell gap to produce an OCB mode liquid crystal cell. A viewing-side polarizing plate (Pol-1) was attached to the manufactured OCB mode liquid crystal cell. On the opposite side, a backlight side polarizing plate was attached. The optically anisotropic layer of the viewing side polarizing plate faces the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing the liquid crystal cell are arranged to be antiparallel. Furthermore, the backlight apparatus was attached and the liquid crystal display device (201) was produced.

[Production of OCB Mode Liquid Crystal Display Device (202)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-2) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (202) was produced.

[Production of OCB Mode Liquid Crystal Display Device (203)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-3) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (203) was produced.

[Production of OCB Mode Liquid Crystal Display Device (204)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-4) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (204) was produced.

[Production of OCB Mode Liquid Crystal Display Device (205)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-5) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (205) was produced.

[Production of OCB Mode Liquid Crystal Display Device (206)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-6) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (206) was produced.

[Production of OCB Mode Liquid Crystal Display Device (207)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-7) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (207) was produced.

[Production of OCB Mode Liquid Crystal Display Device (208)]
In the production of the liquid crystal display device (201), the OCB mode is the same as the liquid crystal display device (201) except that the viewing side polarizing plate (Pol-8) is used instead of the viewing side polarizing plate (Pol-1). A liquid crystal display device (208) was produced.

[Production of OCB Mode Liquid Crystal Display Device (210)]
In producing the liquid crystal display device (201), the liquid crystal display device (201) and the liquid crystal display device (201) were used except that a commercially available cellulose triacetate film “TD80-UF” was used instead of the viewing side polarizing plate (Pol-1). Similarly, an OCB mode liquid crystal display device (210) was produced.

  Subsequently, the following evaluation was performed using the light scattering film and the liquid crystal display device thus obtained.

[Evaluation of light scattering film]
[Evaluation 1: Measurement of refractive index of translucent resin]
The refractive index of the translucent resin used in the light scattering film was measured by the following method.
A liquid is prepared by removing translucent particles from the light scattering coating liquid, and the dry film thickness is 5.0 μm on the support “TD-80U” {triacetyl cellulose film, manufactured by Fuji Film Co., Ltd.}. After coating and solvent drying, an ultraviolet ray having an illuminance of 1.5 kW / cm ² and an irradiation amount of 95 mJ / cm ² was irradiated using an “air-cooled metal halide lamp” {manufactured by Eye Graphics Co., Ltd.} of 160 W / cm. The coating layer was cured to obtain a translucent resin film. Refractive indexes at wavelengths of 435 nm and 545 nm of the respective translucent resin films and the support were measured with an interference film thickness meter “FE-3000” (manufactured by Otsuka Electronics Co., Ltd.).

[Evaluation 2: Refractive Index Measurement of Translucent Particle AS]
Polystyrene and polymethyl methacrylate were mixed at a weight ratio of 1: 1 and then dissolved in chloroform to prepare a concentration of 10 mg / mL. This solution was cast on a glass slide. After drying the solvent, the temperature was raised to 90 ° C. and the curing reaction was continued for 3 hours, and the refractive index of the obtained translucent film and support in the range of 435 nm and 545 nm was measured using an interference film thickness meter “FE-3000”. “Measured by {Otsuka Electronics Co., Ltd.}.

[Evaluation 3: Refractive Index Measurement of Translucent Particle PMMA]
Polymethyl methacrylate was dissolved in chloroform to adjust the concentration to 10 mg / mL. This solution was cast on a glass slide. After drying the solvent, the temperature was raised to 90 ° C. and the curing reaction was continued for 3 hours, and the refractive index of the obtained translucent film and support in the range of 435 nm and 545 nm was measured using an interference film thickness meter “FE-3000”. "Measured by {manufactured by Otsuka Electronics Co., Ltd.}.

[Evaluation 4: Spectral transmittance measurement of light scattering film]
The light transmission spectra of the light scattering films (101) to (108) at wavelengths of 435 nm and 545 nm were measured with a UV-visible spectrophotometer “UV-3150” (manufactured by Shimadzu Corporation).

[Evaluation 5: Haze measurement of light scattering film]
The haze values of the light scattering films (101) to (108) were measured using a measuring instrument “HR-100” {Murakami Color Research Laboratory Co., Ltd.} according to JIS K-7136.

Table 1 shows the structure of the light scattering layer of the obtained light scattering film and the results of its evaluation.
In addition, each abbreviation in Table 1 means the following substances.
AS: Acrylic-styrene copolymer resin particles PMMA: Polymethyl methacrylate resin particles ○: With dispersant ×: Without dispersant

[Evaluation of image display device]
[Evaluation 5: Contrast viewing angle and viewing angle color change of image display device]
A rectangular wave voltage of 55 Hz was applied to the liquid crystal cell. A normally white mode of 2V white display and 5V black display was set. Using the measuring device “EZ-Contrast 1 60D” {ELDIM Co., Ltd.) as the contrast ratio (white luminance / black luminance) as the transmittance ratio (white luminance / black luminance), the white color is changed from white (L1) to white. Measurement was performed in 8 stages until display (L8). The viewing angles in the up-down direction and the left-right direction at which the contrast was 10 or more were determined.

  Here, the vertical and horizontal viewing angles of the liquid crystal cell not provided with the light scattering film are 72 ° and 70 °, respectively. However, when the vertical and horizontal viewing angles are each 80 ° or more, there is no discomfort during viewing. .

  Further, the front contrast value was evaluated in the same manner as described above using a measuring instrument “EZ-Contrast 1 60D” {manufactured by ELDIM Co., Ltd.}. When the value is 350 or more, the required contrast is satisfied. However, if it is less than 350, the color tone between the black display (L1) and the white display (L8) is unclear, and the required contrast cannot be satisfied.

Further, a halftone voltage of 3 V was applied, and the color of an image viewed at a left-right viewing angle of 45 ° was measured using the Lu′v ′ color system. The color change (Δu′v ′) of the transmitted light from the position of the polar angle 60 ° azimuth 45 ° to the position (u′2, v′2) of the polar angle 60 ° azimuth 135 ° is expressed by the following formula ( 6) Calculated by Here, the coordinates on the u′v ′ chromaticity diagram of the transmitted light at the position of polar angle 60 ° and azimuth angle 45 ° are (u′1, v′1), and the position of polar angle 60 ° azimuth angle 135 °. The coordinates on the u′v ′ chromaticity diagram of the transmitted light at (u′2, v′2). The evaluation results are shown in Table 2.
Formula (6): Δu′v ′ = √ [(u′2-u′1) ² + (v′2-v′1) ² ]

  Δu′v ′ is preferably as small as possible, and when it is 0.02 or less, almost no color change is visually observed. Moreover, in the case of 0.02-0.03, a significant difference is recognized by the color change, and the required performance is not satisfied. In the case of 0.03 or more, a noticeable color change is recognized.

  From Table 2, it can be seen that according to the present invention, a light-scattering film having a wide viewing angle and little color-viewing angle dependency can be obtained. In particular, it can be seen that by setting the d / R ratio to 1.4 to 4.0, the viewing angle dependency of the color can be reduced while maintaining the front contrast.

<Example 2>
[Production of light scattering antireflection film]
[Production of Light Scattering Antireflection Film (111)]
On the light-scattering film (101), the coating solution for low refractive index layer (Ln-1) was applied so that the film thickness after drying and curing was 95 nm. After drying the solvent, using a 160 W / cm “air-cooled metal halide lamp” {manufactured by iGraphics Co., Ltd.}, while irradiating 1.5 kW / cm ² and purging with nitrogen so that the oxygen concentration is about 100 ppm, The low refractive index layer was cured by irradiating with 500 mJ / cm ² of ultraviolet rays to obtain a light scattering antireflection film (111).

[Production of Light Scattering Antireflection Film (112)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (102) is used instead of the light scattering film (101). A prevention film (112) was obtained.

[Production of Light Scattering Antireflection Film (113)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (103) is used instead of the light scattering film (101). A prevention film (113) was obtained.

[Production of Light Scattering Antireflection Film (114)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (104) is used instead of the light scattering film (101). A prevention film (114) was obtained.

[Production of Light Scattering Antireflection Film (115)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (105) is used instead of the light scattering film (101). A prevention film (115) was obtained.

[Production of Light Scattering Antireflection Film (116)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (106) is used instead of the light scattering film (101). A prevention film (116) was obtained.

[Production of Light Scattering Antireflection Film (117)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (107) is used instead of the light scattering film (101). A prevention film (117) was obtained.

[Production of Light Scattering Antireflection Film (118)]
In the production of the light scattering antireflection film (111), the light scattering reflection is performed in the same manner as the light scattering antireflection film (111) except that the light scattering film (108) is used instead of the light scattering film (101). A prevention film (118) was obtained.

[Preparation of polarizing plate]
[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-11)]
In the production of the OCB mode viewing side polarizing plate (Pol-1), instead of using the light scattering film (101), it is the same as the polarizing plate (Pol-1) except that the light scattering antireflection film (111) is used. Then, a viewing side polarizing plate (Pol-11) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-12)]
In the production of the OCB mode viewing side polarizing plate (Pol-1), instead of using the light scattering film (101), it is the same as the polarizing plate (Pol-1) except that the light scattering antireflection film (112) is used. Then, a viewing side polarizing plate (Pol-12) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-13)]
In the production of the OCB mode viewing side polarizing plate (Pol-1), instead of using the light scattering film (101), it is the same as the polarizing plate (Pol-1) except that the light scattering antireflection film (113) is used. Then, a viewing side polarizing plate (Pol-13) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-14)]
In the production of the OCB mode viewing side polarizing plate (Pol-1), instead of using the light scattering film (101), it is the same as the polarizing plate (Pol-1) except that the light scattering antireflection film (114) is used. Then, a viewing side polarizing plate (Pol-14) was produced.

[Preparation of OCB mode viewing side polarizing plate (Pol-15)]
In the production of the OCB mode viewing-side polarizing plate (Pol-1), instead of using the light scattering film (101), the same procedure as for the polarizing plate (Pol-1) except that the light scattering antireflection film (115) is used. Then, a viewing side polarizing plate (Pol-15) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-16)]
In the production of the OCB mode viewing-side polarizing plate (Pol-1), instead of using the light scattering film (101), the same procedure as that of the polarizing plate (Pol-1) except that the light scattering antireflection film (116) is used. Then, a viewing side polarizing plate (Pol-16) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-17)]
In the production of the OCB mode viewing side polarizing plate (Pol-1), instead of using the light scattering film (101), it is the same as the polarizing plate (Pol-1) except that the light scattering antireflection film (117) is used. Then, a viewing side polarizing plate (Pol-17) was produced.

[Preparation of OCB Mode Viewing Side Polarizing Plate (Pol-18)]
In the production of the OCB mode viewing-side polarizing plate (Pol-1), the same procedure as in the polarizing plate (Pol-1) was used except that the light scattering antireflection film (118) was used instead of using the light scattering film (101). Then, a viewing side polarizing plate (Pol-18) was produced.

[Production of liquid crystal display device]
[Production of OCB Mode Liquid Crystal Display Device (211)]
In the production of the OCB mode liquid crystal display device (201), instead of using the OCB mode viewing side polarizing plate (Pol-1), the OCB mode viewing side polarizing plate (Pol-11) is used except that it is used. In the same manner as (201), an OCB mode liquid crystal display device (211) was produced.

[Production of OCB Mode Liquid Crystal Display Device (212)]
In the production of the OCB mode liquid crystal display device (201), an OCB mode viewing side polarizing plate (Pol-12) is used instead of the OCB mode viewing side polarizing plate (Pol-1). 201), an OCB mode liquid crystal display device (212) was produced.

[Production of OCB Mode Liquid Crystal Display Device (213)]
In the production of the OCB mode liquid crystal display device (201), a liquid crystal display device (Pol-13) is used in place of the OCB mode viewing side polarizing plate (Pol-1), except that the OCB mode viewing side polarizing plate (Pol-13) is used. 201), an OCB mode liquid crystal display device (213) was produced.

[Production of liquid crystal display device]
[Production of OCB Mode Liquid Crystal Display (214)]
In producing the OCB mode liquid crystal display device (201), a liquid crystal display device is used except that the OCB mode viewing side polarizing plate (Pol-1) is used instead of the OCB mode viewing side polarizing plate (Pol-1). In the same manner as (201), an OCB mode liquid crystal display device (214) was produced.

[Production of OCB Mode Liquid Crystal Display Device (215)]
In the production of the OCB mode liquid crystal display device (201), a liquid crystal display device (Pol-15) is used in place of the OCB mode viewing side polarizing plate (Pol-1), except that the OCB mode viewing side polarizing plate (Pol-15) is used. 201), an OCB mode liquid crystal display device (215) was produced.

[Production of OCB Mode Liquid Crystal Display Device (216)]
In the production of the OCB mode liquid crystal display device (201), an OCB mode viewing side polarizing plate (Pol-16) is used instead of the OCB mode viewing side polarizing plate (Pol-1). 201), an OCB mode liquid crystal display device (216) was produced.

[Production of OCB Mode Liquid Crystal Display Device (217)]
In the production of the OCB mode liquid crystal display device (201), an OCB mode viewing side polarizing plate (Pol-17) is used instead of the OCB mode viewing side polarizing plate (Pol-1). 201), an OCB mode liquid crystal display device (217) was produced.

[Production of OCB Mode Liquid Crystal Display Device (218)]
In the production of the OCB mode liquid crystal display device (201), an OCB mode viewing side polarizing plate (Pol-18) is used instead of the OCB mode viewing side polarizing plate (Pol-1). 201), an OCB mode liquid crystal display device (218) was produced.

  As a result of evaluating the obtained image display devices (211) to (218) according to Example 1, substantially the same effect was obtained. Visibility was improved with low reflectance. The results are shown in Table 3.

  As is apparent from the results shown in Tables 2 and 3, it can be seen that the liquid crystal display device using the light scattering film of the present invention is excellent in view angle and color change. On the other hand, it can be seen that a light-scattering film that does not use a dispersant cannot satisfy the required performance in terms of contrast and color change. It can also be seen that when the layer thickness of the light scattering layer does not satisfy a specific relationship with the particle size of the light scattering particles, it is inferior in terms of contrast and color change. Specifically, in the samples 203 and 213, the light scattering layer is thick and the d / R ratio is large, so that the transmitted light is excessively scattered and the front contrast is lowered. In Samples 204 and 214, since the layer thickness is thin and the d / R ratio is small, light scattering is insufficient and the effect of improving the color change is insufficient. Further, the samples 208 and 218 have high K values and strong blue light scattering, so that the color change cannot be improved. Samples 206 and 216 have large local irregularities in optical performance due to aggregation of inorganic fine particles and light scattering particles, and are unpractical (the measurement values vary greatly, and Tables 2 and 3 describe the worst values). did).

FIGS. 1A to 1C are schematic diagrams showing the relationship between the layer thickness (d) of the light scattering layer and the average particle diameter (R) of the light scattering particles.

Explanation of symbols

2 Scattered particles 1 Light scattering layer

Claims (8)

A light scattering film having a light scattering layer formed of at least one kind of light scattering particles, a translucent resin, and a dispersant on a support, wherein the layer thickness (d) of the light scattering layer is that of the light scattering particles. The oxide fine particles of at least one metal selected from titanium, zinc, and aluminum having a particle size of 1.4 to 4.0 times the particle size (R) and the translucent resin having a particle size of 100 nm or less. When the refractive index of at least one kind of light scattering particles at wavelengths of 435 nm and 545 nm is n _P435 and n _P545 , respectively, and the refractive index of the translucent resin at 435 nm and 545 nm is n _B435 and n _B545 , respectively. The light-scattering film characterized by satisfy | filling following numerical formula (1)-(3) simultaneously.
Formula (1): n _B435 > n _P435
Formula (2): n _B545 > n _P545
Formula (3): 0.9 <(n _P435 / n _B435 ) / (n _P545 / n _B545 ) <1.0 2. The light scattering film according to claim 1, further satisfying the following formula (4) when spectral transmittances at wavelengths of 435 nm and 545 nm are respectively T ₄₃₅ and T ₅₄₅ .
Formula (4): 0.33 < _T435 / _T545 <1.25 The light scattering film according to claim 1 or 2, further satisfying the following mathematical formula (5).
Formula (5): 1.005 <n _B435 / n _B545 <1.360   The compound which comprises light-scattering particle | grains contains the compound which has an aromatic ring, The light-scattering film in any one of Claims 1-3 characterized by the above-mentioned.   The light-scattering film according to claim 1, wherein the dispersant is an anionic dispersant.   The polarizing plate which has a polarizing film and a protective film on both sides of this polarizing film, Comprising: At least one protective film is a light-scattering film in any one of Claims 1-5.   An image display device comprising the light scattering film according to claim 1 or the polarizing plate according to claim 6.   A liquid crystal display device having a TN mode or OCB mode liquid crystal cell, comprising the light scattering film according to claim 1 or the polarizing plate according to claim 6. apparatus.

Images