KR20100007441A - Optical film without rainbow, polarizing plate and display device having the same - Google Patents

Abstract

PURPOSE: An optical film without rainbow, polarizing plate and display device having the same is provided to improve the visibility and to remove the interference effect of coating. CONSTITUTION: The base surface(2) become rough at the upper part of one side of the base film(1) after the solvent application and drying process. The hard coating layer(3) is etched is formed in upper part the substrate surface. The hard coating layer appears through the interfacial scattering as the hard coating optical film eliminating the dark fringe.

Description

Optical film without interference pattern, polarizing plate and image display device using same {Optical Film without Rainbow, Polarizing Plate and Display Device having the Same}

The present invention relates to an optical film, and to a polarizing plate and an image display device using the same, which effectively removes interference effects generated during coating to improve visibility.

Generally, a functional optical coating in which functional coating layers such as a hard coating layer, an antistatic coating layer, and a low reflection coating layer are laminated on surfaces of a liquid crystal display (LCD), a plasma display (PDP), a cathode ray tube (CRT), and an electroluminescent display (EL). Films are widely used.

However, when the coating for forming the functional optical coating film is performed, interference occurs between the functional coating layer surface reflected light and the interface reflected light between the base film and the functional coating layer to generate an interference effect similar to rainbow colors. In particular, when the refractive index of the base film and the refractive index of the functional coating layer is different, such interference effect is strongly generated, resulting in a large degradation of the image.

In the art, various methods have been attempted to improve the problem of the interference effect. Thus, Japanese Laid-Open Patent Publication No. 2003-75605 discloses a medium refractive index layer having a refractive index of 1.5 to 1.7 and a refractive index on a transparent substrate film. The antireflection hard coating sheet laminated in the order of the high refractive index layer of 1.6 to 1.8 and the low refractive index layer made of a material having a lower refractive index than the high refractive index layer is used to improve the interface reflection and the interference effect. .

In addition, in Korean Patent Laid-Open Publication No. 2006-0051536, a weight average molecular weight of 200 or more and 1000 or less and a resin having three or more functional groups and a thin layer made of a permeable solvent are formed, and a hard coat layer is formed on the thin layer to form a thin layer. A method for reducing interfacial reflection and interference effects is proposed.

As described above, it can be seen that the conventional method of improving the interface reflection and interference effect is performed by forming a coating layer having separate optical characteristics or arranging the layers appropriately in consideration of the refractive index of the substrate and the coating layer. have.

The present invention is a substrate in which the interference fringe is removed by a method of roughening the surface of the base film in an easy way that does not require a separate coating layer and a complex coating layer formation and arrangement process to remove the interference effect as described above I would like to present a film. In detail, the surface of the base film is roughened by an expansion solvent to roughen the surface of the base film, thereby significantly reducing interference effects regardless of the refractive index of the base film and the coating layer, and a polarizing plate and an image display using the same. I would like to present a device.

By removing the interference effect by causing interfacial scattering through the roughening of the base film as described above, it is possible to greatly extend the refractive index range of the coating layer material, thereby greatly expanding the range of material selection used in the coating layer. In addition, even if the coating accuracy of the coating layer is slightly lower, the interference effect due to the thickness difference can be eliminated, the productivity can be greatly improved.

The present invention is applied to the surface of the base film, the solvent, and then dried to form an uneven layer on the surface of the base film, and the surface interference effect is removed including the step of laminating a functional coating layer on the uneven layer Its features are in the manufacturing method.

In addition, the present invention has another feature of an optical film in which a functional coating layer is laminated on a base film, and irregularities are formed at an interface between the base film and the functional coating layer.

In addition, the present invention has another feature in the polarizing plate provided with the optical film and the image display device provided with the polarizing plate.

Other specific embodiments of the present invention will be described in detail in the following detailed description.

The present invention is to remove the interference effect that is commonly seen in the optical film, it is possible to provide a coating film having excellent visibility, and a polarizing plate and an image display device using the same without deteriorating other mechanical and optical properties.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of an optical film having a three-layer structure manufactured according to an embodiment of the present invention. Specifically, after applying a solvent to at least one surface of the base film 1, Hard coating optical film or anti-static hard to form a hard coating layer (3) or an antistatic hard coating layer (3) on the cotton substrate surface (2), the top surface of the roughened substrate surface to remove interference patterns through interfacial scattering A coating optical film is shown.

2 is a schematic cross-sectional view of an optical film having a four-layer structure manufactured according to one embodiment of the present invention. Specifically, the coating film is coated on at least one surface of the base film 1 and then dried. A hard coating layer 3 or an antistatic hard coating layer 3 is formed on the surface of the cotton substrate surface 2 and the roughened substrate surface, and a low refractive index layer 4 is formed on the upper surface of the formed hard coating layer or the antistatic hard coating layer. Represents a low reflection hard coating optical film or a low reflection antistatic hard coating optical film formed by removing the interference effect through interfacial scattering.

The present invention is applied to the surface of the base film, the solvent, and then dried to form an uneven layer on the surface of the base film, and the surface interference effect is removed including the step of laminating a functional coating layer on the uneven layer There is a characteristic feature of the technical configuration in the manufacturing method, which will be described in more detail as follows.

The base film may be used as long as it is a transparent plastic film as an optical transparent base film generally used in the art. Specifically, cycloolefin derivatives having units of monomers containing cycloolefins, such as norbornene-based or polycyclic norbornene-based monomers, include diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose, ethylene-acetic acid Celluloses such as vinyl cellulose copolymer, propionyl cellulose, butyryl cellulose and acetyl propionyl cellulose; Or polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl Thermoplastic polymers such as alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyethylene naphthalate, polyurethane and epoxy It is possible to use a single compound or a mixture of two kinds selected from among them, and these may use an unstretched, uniaxial or biaxially oriented film. Preferably, a monoaxial or biaxially stretched polyester film, a polymethyl methacrylate film, a polycycloolefin-based film, which is excellent in transparency and heat resistance, is made of triacetyl cellulose and isobutyl ester cellulose in terms of transparency and optical anisotropy. It is preferable to use a film or the like.

It is preferable to use a thin thickness of such a base film, but if the thickness is too thin, the workability is inferior. On the other hand, if the thickness is too thick, problems such as deterioration of transparency or the weight of the polarizing plate are generated. The range of 1000 μm is preferably used in the range of 40 to 100 μm.

Solvents used to roughen the surface of the base film may be used as long as it can swell the base film. Specifically, alcohols, ketones, esters, ethers, nitrogen compounds, and halogenated hydrocarbons may be used. It is possible to use a single compound or a mixture of two or more selected from the group and aromatic hydrocarbons. More specifically, methanol, ethanol, isopropyl alcohol, butanol, isobutyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone Alcohol, methyl formate, methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, diisopropyl ether, tetrahydrofuran, dioxane, dioxolane, nitromethane, N-methylpyrrolidone, N, N ' A single compound or a mixture of two or more selected from dimethylformamide, methylene chloride, chloroform, trichloroethane, tetrachloroethane, toluene and xylene may be used.

The present invention is to remove the interference effect by the reflected light by applying a solvent that can swell the base film (swelling) to form irregularities, the solvent is applied so that the thickness of the humidity film 0.5 to 30㎛ range. At this time, the coating is not particularly limited to the coating method generally used in the art, specifically, a die coater, air knife, air reverse roll, air blade, cast steel, and gravure light may be used. Subsequently, when the solvent is completely dried at room temperature to 100 ° C. for 5 to 100 seconds, the surface of the expanded base film is unevenly solidified by volatilization of the solvent, thereby causing micro size, specifically, surface roughness (Ra) 0.05. By forming irregularities in the range of 5 μm to effectively roughen the surface of the base film. The surface of such roughened base film can be more clearly confirmed by the SEM photograph of FIG.

When the thickness of the solvent to be applied is less than 0.5㎛ thickness of the surface of the base film (swelling) layer (swelling) is insufficient enough to roughen the surface to cause the interfacial scattering, it is not possible to effectively remove the interference fringe, thickness When the thickness exceeds 30㎛, the degree of swelling of the surface of the base film is so severe that it swells not only to the base surface but also into the base material, and the entire base film is severely curled. There is a disadvantage.

The substrate film prepared above has a haze of 1% or more, preferably 1 to 20%, and a surface roughness (Ra) of 0.05 μm or more, preferably 0.05 to 5 μm. The interference effect due to the reflected light on the surface of the functional coating layer applied on the film is eliminated.

In addition, the present invention is characterized in that the functional coating layer is laminated on the base film prepared above, the optical film formed with irregularities at the interface between the base film and the functional coating layer. At this time, the unevenness is formed by a solvent for expanding the base film. The functional coating layer is generally applied in the art, and specifically, may be used as a single layer or a composite layer selected from a hard coating layer, an antistatic hard coating layer, an antiglare coating layer, an antistatic antiglare coating layer, and a low reflection coating layer. .

The composition and the mixing ratio of each of the functional coating layer is not particularly limited to those commonly used in the art, which will be described in more detail as follows.

First, the hard coating layer is formed by using a hard coating solution composition containing 10 to 60% by weight of a polyfunctional (meth) acrylate, 1 to 10% by weight of a photopolymerization initiator, and 30 to 80% by weight of an organic solvent as an ultraviolet curable resin composition. . In this case, the (meth) acrylate means both acrylate and methacrylate.

Specifically, the polyfunctional (meth) acrylate is dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acryl Rate, (meth) acrylic ester, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, tris (2-hydroxyethyl hydroxyethyl) isocyanurate tri (meth) acrylate, ethylene glycol Di (meth) acrylate, propylene glycol (meth) acrylate, 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylic Latene, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth ), Isodecyl (meth) acrylate, stearyl (meth) acrylate, tetraperfuryl (meth) acrylate and phenoxyethyl (meth) acrylate can be used a single compound or a mixture of two or more thereof. .

Specifically, the photopolymerization initiator is diphenyl ketone benzyl dimethyl ketal, acetphenone dimethyl ketal, p-dimethylamine benzoic acid ester, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, Dimethoxy-2-phenylacetophenone, anthraquinone, 2-aminoanthraquinone, fluorene, triphenylamine, carbazole, benzophenone, p-phenylbenzophenone, 3-methylacetophenone, 4,4-dimethoxyaceto A single compound or a mixture of two or more selected from phenone, 4,4-diaminobenzophenone, benzoin and 2-ethylthioxanthone can be used.

The organic solvent is used to maintain the thickness control and good coating properties of the functional coating film, it can be used for all organic solvents having no problem in compatibility with polyfunctional (meth) acrylate. Specifically, methanol, ethanol, isopropanol, propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, butyl acetate, dimethylformamide, diacetone alcohol, ethylene glycol isopropyl alcohol, propylene glycol isopropyl alcohol, methyl A single compound or a mixture of two or more selected from ethyl ketone and N-methylpyrrolidone may be used.

In addition to the above components, in order to improve the surface strength of the functional coating layer, nano-silica particles of organic-inorganic hybrid type in which the hydroxyl group on the silica surface is substituted with acrylate; Photopolymerization initiation aids such as triethylamine, diethylamine, methyldiethanolamine, ethanolamine, 4-dimethylamino-benzoic acid and isoamyl-4-dimethylaminobenzoate for improving the photopolymerization efficiency; And additives such as fillers, leveling agents, antifoams, ultraviolet absorbers, antioxidants, and the like.

The antistatic hard coating layer is formed using an antistatic hard coating solution composition in which a conductive material is added to the hard coating solution composition or a part of the antistatic hard coating solution is replaced with a conductive material. The conductive material is generally used in the art and is not particularly limited in kind, specifically, cationic surfactants such as quaternary ammonium salts, phosphonium salts, and sulfonium salts; Anionic surfactants such as carboxylic acid type, sulfonate type, sulfuric acid type, phosphate type and phosphite type; Cationic surfactants such as sulfo betaine, alkyl betaine and alkylimidazolium betaine; Various surfactants, such as nonionic surfactant, such as a polyhydric alcohol derivative, a sorbitan fatty acid monoester diester, and a polyalkylene oxide derivative, can be used.

Moreover, the homopolymer of a cation system, such as a quaternary ammonium salt, a cation system, such as a betaine compound, an anion system, such as a sulfonate, or the homopolymer of the monomer which has a nonionic ionic conductive group, such as glycerin, or another monomer copolymerizable with the said monomer Polymers having ionic conductivity such as copolymers with polymers, polymers having a repeating unit derived from acrylate or methacrylate having a quaternary ammonium base; Permanent antistatic agents in which hydrophilic polymers such as polyethylene methacrylate and acrylic resins are mixed; Acetylene Black, Natural Graphite, Artificial Graphite, Titanium Black, Zinc Oxide, Tin Oxide, Tin Coated Titanate Compound, Nickel Flake, Phosphorus Doped Tin Oxide, Antimony Doped Tin Oxide, Antimony Oxide, Indium Tin Oxide, Cerium Oxide, Aluminum Oxide, Dioxide Conductive fillers such as titanium and zirconium oxide; Nano-metal oxide particles of an organic-inorganic hybrid type by replacing hydroxyl groups on the surface of the metal oxide particles with acrylates; And a single compound or a mixture of two selected from conductive polymers such as polypyrrole, polythiophene, and polyaniline. Preferably, a metal compound of antimony-doped tin oxide particles is used.

The antiglare coating layer or the antistatic antiglare coating layer is formed by using an antiglare coating composition or an antistatic antiglare coating composition in which micro particles are dispersed to impart antiglare to the hard coating solution composition or the antistatic hard coating solution composition.

The microparticles for imparting anti-glare property are generally used in the art, and there is no particular limitation, and generally, inorganic particles such as silica or polymer particles such as polymethyl methacrylate (PMMA) may be used. In order to improve dispersibility, such particles may be used as monodisperse particles, polydisperse particles having a size of 1 to 20 μm, or mixed with the monodisperse and polydisperse particles.

In addition, the present invention can form a low reflection coating layer with a functional coating layer, in general, the thickness of the coating layer is λ / (4 × n _{coating layer} ) by the interference principle of light on the coating _layer , the refractive index is When the low refractive layer represented by 1 is laminated, the phase of the light of the surface reflection and the phase of the light reflected at the interface of the functional coating layer and the low refractive layer are reversed to each other, thereby canceling the light and minimizing the reflected light.

[Equation 1]

(n _{coating layer} ) ² = n _{base layer} × n _{air layer}

In Equation 1, n represents a refractive index.

When the refractive index of the optical film generally used by Equation 1 is 1.5, the low refractive index layer laminated on the coating layer may be designed to have a refractive index of 1.3 to 1.4 and a thickness of about 100 nm.

As described above, the functional coating layer may be coated by a method generally used in the art, and specifically, a die coater, an air knife, a reverse roll, a blade, casting, and gravure may be used. At this time, the thickness of the functional coating layer is usually about 0.1 to 200㎛, preferably about 1 to 50㎛, most preferably maintain 3 to 30㎛. The coated composition is dried by evaporation of volatiles at a temperature of 30 to 150 ° C. for 1 second to 2 hours, preferably 5 seconds to 1 hour. The curing process is performed with UV light, wherein the irradiation amount of UV light is about 0.01 to 10 J / cm ² , preferably maintained in the range of 0.1 to 2 J / cm ² .

The optical film produced by the above method is effectively removed interference fringe through the fluorescent light reflection appearance evaluation shows excellent visibility as a functional film for optics.

In addition, the present invention has a feature in the technical configuration of the polarizing plate provided with the optical film prepared above.

The polarizing plate may be used without any particular limitation in the art, and may include a polarizing plate having at least one side of the polarizer formed of a polarizer protective film.

The polarizer may be an optical film that converts incident natural light into a desired single polarization state (linear polarization state), and may be one in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin film. The polarizer is a step of uniaxially stretching a polyvinyl alcohol-based resin film, dyeing the stretched polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, and polyvinyl alcohol with the dichroic dye adsorbed. It manufactures through the process of processing a system resin film with aqueous boric acid solution, and the process of washing with water after the process by the said boric acid aqueous solution.

The polyvinyl alcohol-based resin constituting the polarizer may be obtained by saponifying a polyvinyl acetate-based resin, and the polyvinyl acetate-based resin is specifically copolymerizable with polyvinyl acetate or vinyl acetate, which is a homopolymer of vinyl acetate. And copolymers with other monomers. At this time, the other monomer copolymerizable with vinyl acetate can specifically use unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, acrylamides having an ammonium group, and the like. The saponification degree of the polyvinyl alcohol-based resin is usually maintained at about 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin may be modified and used. Specifically, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used.

The process of uniaxially stretching the polyvinyl alcohol resin film may be performed before dyeing, simultaneously with or after dyeing, and when performing uniaxial stretching after dyeing, may be performed before boric acid treatment or during boric acid treatment. In addition, uniaxial stretching can be performed in these plural steps. Uniaxial stretching is dry stretching such as stretching uniaxially between rolls of different circumferential speeds, stretching uniaxially using heat rolls, stretching in air, or wet stretching in a state in which the solvent is swelled. Can be performed. At this time, a draw ratio is about 3 to 8 times normally.

As a method for dyeing the stretched polyvinyl alcohol-based resin film with a dichroic dye, for example, the polyvinyl alcohol-based resin film can be immersed in an aqueous solution containing a dichroic dye. In this case, specifically, as a dichroic dye, iodine or a dichroic dye may be used, and the polyvinyl alcohol-based resin film is preferably subjected to a pretreatment process of pre-immersion in water before dyeing treatment.

When iodine is used as the dichroic dye, a method of dipping and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide can be generally used. The content of iodine contained in the aqueous solution is usually 0.01 to 1 parts by weight based on 100 parts by weight of distilled water, the content of potassium iodide is usually maintained in the range of 0.5 to 20 parts by weight based on 100 parts by weight of distilled water. The temperature of the aqueous solution is usually in the range of 20 to 40 ℃, the immersion time (dyeing time) of the polyvinyl alcohol-based resin film in the aqueous solution is usually maintained in the range of 20 to 1,800 seconds.

In addition, when using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing water-soluble dichroic dye can be used normally. The content of the dichroic dye contained in the aqueous solution is usually maintained in the range of 0.01 to 1 part by weight based on 100 parts by weight of distilled water, and the content of potassium iodide is usually about 1 × 10 ^-4 to 10 parts by weight based on 100 parts by weight of distilled water. Preferably, it maintains the range of 1x10 <^-3> -1 weight part. This aqueous solution may further contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the aqueous solution is usually in the range of 20 to 80 ℃, the immersion time (dyeing time) of the polyvinyl alcohol-based resin film in the aqueous solution is usually maintained in the range of 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid. The content of boric acid contained in the aqueous solution containing boric acid is usually maintained in the range of 2 to 15 parts by weight, preferably 5 to 12 parts by weight, relative to 100 parts by weight of water. Moreover, when using iodine as a dichroic dye, it is preferable that the said boric acid containing aqueous solution contains potassium iodide. At this time, the content of potassium iodide contained in the aqueous solution containing boric acid is maintained in the range of 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight with respect to 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually maintained in the range of 60 to 1,200 seconds, preferably in the range of 150 to 600 seconds, more preferably in the range of 200 to 400 seconds. The temperature of the boric acid containing aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC, More preferably, it maintains 60-80 degreeC.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The washing process is carried out, for example, by immersing the boric acid-treated polyvinyl alcohol resin film in water. At this time, the temperature of water is about 5-40 degreeC normally, and immersion time is about 1 to 12 second normally.

After washing with water, a drying treatment is performed to obtain a polarizer. The drying treatment can generally be performed using a hot air dryer or a far infrared heater. At this time, the temperature of the drying treatment is usually maintained in the range of 30 to 100 ° C, preferably in the range of 50 to 80 ° C, and the time of the drying treatment is usually in the range of 60 to 600 seconds, preferably in the range of 120 to 600 seconds.

The polarizer manufactured by the above method maintains the thickness in the range of 5-40 micrometers.

The polarizer protective film is generally used in the art and is not particularly limited as long as it is a plastic film having transparency, and it is preferable to use one having excellent mechanical strength, thermal stability, moisture shielding, and isotropy with transparency. Specifically, the polarizer protective film may include a polyester film such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose films such as diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose, propionyl cellulose, butyryl cellulose and acetyl propionyl cellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene films such as polystyrene and acrylonitrile-styrene copolymers; Polyolefin-based films such as polyethylene, polypropylene, cyclo-based or norbornene-structured polyolefin-based films and ethylene propylene copolymers; Ethylene-vinyl acetate copolymer film; Polyamide film; Polyimide, polyetherimide film; Polyether sulfone-based film; Sulfone film; Polyvinyl chloride, polyvinylidene chloride films; Polyvinyl alcohol, polyvinyl acetal film; Polyether ketone, polyether ether ketone film; Polyurethane, an epoxy film, etc. can be used, These can use an unstretched, uniaxial or biaxially stretched film. Among them, a uniaxial or biaxially stretched polyester film, a polymethyl methacrylate film or a polycycloolefin-based film having excellent transparency and heat resistance, but triacetyl cellulose and isobutyl ester cellulose in terms of transparency and optical anisotropy. It is more preferable to use.

The polarizer protective film has a thickness of 8 to 1000 ㎛ range, preferably 20 to 100 ㎛ range, the thickness of the polarizer protective film is preferably a thin one, but if the thickness is too thin, the strength is lowered to reduce workability If the thickness is too thick, the transparency may be lowered or the weight of the polarizing plate may increase, so it is preferable to maintain the above range.

In addition, at least one functional film selected from a protective layer, a reflective layer, an anti-glare layer, a phase difference plate, an optical viewing angle film, and a luminance enhancement film may be further laminated on the polarizing plate according to the present invention.

In addition, the present invention is characterized in the technical configuration of the image display device provided with the polarizing plate manufactured above. Specifically, by incorporating a polarizing plate on which a coated film made in accordance with the present invention is laminated to a display device, various image display devices with excellent visibility can be manufactured. The coating film of the present invention can be preferably used as an LCD of various driving methods such as reflective, transmissive, semi-transmissive LCD or TN type, STN type, OBC type, HAN type, VA type and IPS type. In addition, the coated film of the present invention has excellent visibility and can be used in various image display devices such as plasma displays, field emission displays, organic EL displays, inorganic EL displays, and electronic papers.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Example  One

Apply methyl ether ketone (MEK) solvent on a triacetyl cellulose film (29.7 cm × 21.0 cm × 40 μm, TAC) with a Meyer bar to apply a moisture film thickness of 5 μm for 1 minute at 40 ° C. Hot air was dried. The surface roughness roughened by the solvent treatment was measured by haze measurement and surface roughness Ra by confocal microscope.

Thereafter, the hard coating liquid (DN-0081, manufactured by JSR) was applied with a Meyer bar to have a dry coating thickness of 5 μm, and hot-air dried at 70 ° C. for 1 minute, and then cured at 750 mJ / cm ² . An optical film was prepared.

Example 2: solvent Treatment layer  Thickness change

In the same manner as in Example 1, but using a methyl ethyl ketone (MEK) to prepare a base film having a moisture film thickness of 10㎛, to prepare an optical film using the prepared base film.

Example  3: Type change of solvent (single solvent)

In the same manner as in Example 1, using ethyl acetate instead of methyl ethyl ketone (MEK) as a solvent to prepare a base film having a moisture film thickness of 5㎛, using the prepared base film optical film Prepared.

Example  3-1 to 3-5: change of solvent type (single solvent)

In the same manner as in Example 1, but instead of methyl ethyl ketone (MEK) as a solvent, methanol (3-1), tetrahydrofuran (3-2), cyclohexanone (3-3), methylene chloride (3- 4) and dimethylformamide (3-5) were used to prepare respective base films each having a moisture film thickness of 5 μm, and each optical film was prepared using the prepared base films.

Example 4: Type change of base film and type of solvent (mixed solvent)

In the same manner as in Example 1, but using a triacetyl cellulose film (29.7cm x 21.0cm x 80㎛, TAC), methyl ethyl ketone (MEK) and propylene glycol mono instead of methyl ethyl ketone (MEK) as a solvent Using a mixed solvent mixed with methyl ether acetate (PGMEA) in a 1: 2 weight ratio to prepare a base film having a moisture film thickness of 5㎛, to prepare an optical film using the prepared base film.

Example  4-1 to 4-5: type change of solvent (mixed solvent)

The same procedure as in Example 1, except that methyl ethyl ketone (MEK) and propylene glycol monomethyl ether acetate (PGMEA) in a 1: 1 weight ratio (4-1) instead of methyl ethyl ketone (MEK), ethyl acetate ( EA) and propylene glycol monomethyl ether acetate (PGMEA) were used to prepare respective base films each having a thickness of 5 μm using a 1: 1 weight ratio (4-2). Each optical film was prepared.

Example 5: type change of functional coating layer Monolayer )

In the same manner as in Example 1, using an antistatic hard coating solution (EC190-03, manufactured by Kriya) instead of the hard coating solution (DN-0081, manufactured by JSR) to an optical film having a dry film thickness of 3㎛ Prepared.

Example 6: Type change of functional coating layer Composite layer )

After performing the same as in Example 1, using a hard coating solution (DN-0081, JSR Co., Ltd.) to prepare a coating film having a dry coating thickness of 5㎛, low refractive index coating solution (TU-2189, JSR company) Was used to produce a low reflection hard coating optical film having a dry film thickness of 100nm.

Example 7: Type change of functional coating layer Composite layer )

A coating film having a dry coating thickness of 3 μm was carried out in the same manner as in Example 1, but using an antistatic hard coating liquid (EC190-03, manufactured by Kriya) instead of the hard coating liquid (DN-0081, manufactured by JSR). After the production, a low reflection hard coating optical film having a dry coating thickness of 100 nm was manufactured using a low refractive index coating liquid (TU-2189, manufactured by JSR).

Comparative example 1: solvent Treatment layer  exclusion

In the same manner as in Example 1, except that the coating layer formation process using methyl ethyl ketone (MEK), except dry coating film thickness 5 using a hard coating solution (DN-0081, JSR) directly to the triacetyl cellulose film An optical film having a thickness was prepared.

Comparative example 2: solvent Treatment layer  Exclusion and Change of Type of Transparent Substrate Film

The same procedure as in Example 1, except that a triacetyl cellulose film (29.7 cm × × 21.0 cm × × 80 μm, TAC), methyl ethyl ketone (MEK) to exclude the coating layer forming process, triacetyl cellulose film An optical film having a dry coating thickness of 5 μm was prepared using a hard coating solution (DN-0081, manufactured by JSR Co., Ltd.) directly.

Comparative example 3: solvent Treatment layer  Exclusion and Functional layer  Type change

The same process as in Example 1 except that methyl ethyl ketone (MEK) was used to exclude the coating layer forming process, and then dried using an antistatic hard coating solution (EC190-03, manufactured by Kriya) directly on the triacetylcellulose film. An optical film having a coating thickness of 3 μm was prepared.

Experimental Example

The optical films prepared in Examples 1 to 7 and Comparative Examples 1 to 3 measured physical properties in the same manner as described below, and the results are shown in Tables 1 and 2 below.

[Measurement of physical properties]

1) Transmittance and haze: Total light transmittance and haze were measured using a spectrophotometer (HZ-1, manufactured by Suga Japan).

2) Reflectance: The reflectance measuring instrument (UV-2450, manufactured by Shimatsu, Japan) and MPC-2200 (made by Shimatsu, Japan) were used.

3) Surface irregularities roughness value: The surface average roughness value Ra was measured by measuring the film surface at 1000 times magnification using a confocal microscope (VK-9500, manufactured by Keyence).

4) Interference pattern removal: After the coated film was bonded to the black acrylic plate using an adhesive, the interference pattern removal was visually evaluated by reflecting fluorescent light and three wavelength stand light.

◎: 3 wavelength stand, fluorescent lights are not visible interference

○: 3 wavelength stand weakly acknowledged, fluorescent light not visible

△: 3 wavelength stand strong poet, fluorescent light weak poet

X: 3 wavelength stand river poet, fluorescent river poet

(5) Pencil hardness: Using a pencil hardness tester (PHT, manufactured by Korea's Seokbo Science Co., Ltd.), apply a 500g load and measure the pencil hardness. Use a Mitsubishi product pencil and perform 5 times per hardness pencil. If there were two or more gases, it was judged as defective.

Kisuke: OK

Kisuke 1: OK

More than 2 Gis

(6) Scratch Resistance: The steel wool test machine (WT-LCM100, manufactured by Korea Techtec Co., Ltd.) was used to test the scratch resistance by reciprocating 10 times under 1kg / (2cm × 2cm). Steel wool uses # 0000.

A: 0 scratches

A ': 1 or 10 scratches

B: 11 to 20 scratches

C: 21 to 30 scratches

D: 31 scratches or more

(7) Adhesion: After drawing 11 straight lines on the coated surface of the film at 1mm intervals and making 100 squares, use the tape (CT-24, Nichi Nichi) to carry out three peeling tests. . Three 100 squares were tested and the average recorded. Adhesion was recorded as in Equation 2 below.

[Equation 2]

Adhesion = n / 100

In Equation 2, n is the number of squares that are not peeled out of all the squares, and 100 is the number of total squares. In other words, if none have been peeled off, record as 100/100.

(8) Surface resistance: Measure the surface resistance using a surface resistance meter (mCP-HT450, Mitsubishi Chemical, Japan) on the coated surface of the film. When the voltage starts from 10V and the surface resistance is over, the voltage is measured in the order of 100V, 250V, 500V and 1000V.

division Example 1 Example 2 Example 3 Example 3-1 Example 3-2 Example 3-3 Example 3-4 Example 3-5 Haze base material before haze 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.3 Haze base material after roughening 7.2 11.2 6.9 5.2 7.0 8.3 5.8 8.5 Substrate Ra after roughening 0.12 0.15 0.11 0.08 0.12 0.13 0.08 0.13 Haze after functional coating 0.2 0.3 0.3 0.2 0.2 0.3 0.3 0.2 Interference Strip Removability ◎ ◎ ○ ○ ◎ ◎ ○ ◎ reflectivity 4.1 4.2 4.2 4.1 4.1 4.2 4.1 4.1 Pencil hardness 2H 2H 2H 2H 2H 2H 2H 2H Scratch resistance A ' A ' A ' A ' A ' A ' A ' A ' Adhesion 100/100 100/100 100/100 100/100 100/100 100/100 100/100 100/100 Surface Resistance (Ω / □) 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ¹⁵

division Example 4 Example 4-1 Example 4-2 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Haze base material before haze 0.3 0.2 0.2 0.4 0.3 0.3 0.2 0.3 0.3 Haze base material after roughening 6.5 6.3 7.1 7.1 7.5 7.3 - - - Substrate Ra after roughening 0.08 0.10 0.11 0.13 0.12 0.11 - - - Haze after functional coating 0.3 0.3 0.3 0.2 0.4 0.3 - - - Interference Strip Removability ○ ○ ◎ ◎ ◎ ◎ △ △ X reflectivity 4.2 4.2 4.2 4.3 1.0 0.8 4.2 4.1 4.3 Pencil hardness 3H 3H 3H 2H 2H 2H 2H 3H 2H Scratch resistance A ' A ' A ' A ' A ' A ' A ' A ' A ' Adhesion 100/100 100/100 100/100 100/100 100/100 100/100 100/100 100/100 100/100 Surface Resistance (Ω / □) 10 ¹⁵ 10 ¹⁵ 10 ¹⁵ 10 ⁸ 10 ¹⁵ 10 ⁸ 10 ¹⁵ 10 ¹⁵ 10 ⁸

As shown in Table 1 and Table 2, Examples 1 to 7, wherein an optical film was prepared using a base film formed by coating a solvent on the surface of the base film according to the present invention to form irregularities, It was confirmed that the interference fringe removal property was very excellent while maintaining the mechanical and optical properties equivalent to those of Comparative Examples 1 to 3, which were prepared. This was confirmed that the surface of the base film is roughened by the irregularities formed by the solvent, resulting in improved haze value and surface roughness (Ra) value.

Figure 1 is a schematic cross-sectional view of a coating film having a three-layer structure prepared according to one embodiment of the present invention.

Figure 2 is a schematic cross-sectional view of a coating film having a four-layer structure manufactured according to one embodiment of the present invention.

[Description of Symbols for Main Parts of FIGS. 1 and 2]

1: transparent film 2: roughening structure

3: (anti-static) hard coating layer 4: low refractive index layer

3 is a SEM photograph of the surface of the roughened base film according to an embodiment of the present invention.

Claims (16)

Applying a solvent to the surface of the base film and then drying to form an uneven layer on the surface of the base film; Method of manufacturing an optical film from which the surface interference effect is removed, comprising the step of laminating a functional coating layer on the uneven layer. The method of claim 1, wherein the base film is an optical transparent base film. The method of claim 1, wherein the solvent is a single compound or a mixture of two or more selected from alcohols, ketones, esters, ethers, nitrogen compounds, halogenated hydrocarbons, and aromatic hydrocarbons. The method of claim 1 or 3, wherein the solvent is methanol, ethanol, isopropyl alcohol, butanol, isobutyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, acetone, methyl ethyl ketone, methyl iso Butyl ketone, cyclohexanone, diatone alcohol, methyl formate, methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, diisopropyl ether, tetrahydrofuran, dioxane, dioxolane, nitromethane, N -A method for producing an optical film, which is a single compound or a mixture of two or more selected from methylpyrrolidone, N, N'-dimethylformamide, methylene chloride, chloroform, trichloroethane, tetrachloroethane, toluene and xylene. The method of claim 1, wherein the solvent is applied in a thickness range of 0.5 to 30 μm. The method of claim 1, wherein the uneven surface roughness (Ra) is 0.05 to 5㎛ range of the manufacturing method of the optical film. The method of claim 1, wherein the functional coating layer is a single layer or two or more composite layers selected from a hard coating layer, an antistatic hard coating layer, an antiglare coating layer, an antistatic antiglare coating layer, and a low reflection coating layer. An optical film in which a functional coating layer is laminated on a base film, and irregularities are formed at an interface between the base film and the functional coating layer. The optical film of claim 8, wherein the base film is an optical transparent base film. The optical film of claim 8, wherein the unevenness is formed by a solvent for expanding a base film. The optical film of claim 10, wherein the base film expansion solvent is a single compound or a mixture of two or more selected from alcohols, ketones, esters, ethers, nitrogen compounds, halogenated hydrocarbons, and aromatic hydrocarbons. The method of claim 11, wherein the base film expansion solvent is methanol, ethanol, isopropyl alcohol, butanol, isobutyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, acetone, methyl ethyl ketone, methyl iso Butyl ketone, cyclohexanone, diatone alcohol, methyl formate, methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, diisopropyl ether, tetrahydrofuran, dioxane, dioxolane, nitromethane, N- An optical film comprising a single compound or a mixture of two or more selected from methylpyrrolidone, N, N'-dimethylformamide, methylene chloride, chloroform, trichloroethane, tetrachloroethane, toluene and xylene. The optical film of claim 8, wherein the functional coating layer is a single layer or a composite layer selected from a hard coating layer, an antistatic hard coating layer, an antiglare coating layer, an antistatic antiglare coating layer, and a low reflection coating layer. The optical film of claim 8, wherein the surface of the base film on which the irregularities are formed has a haze of 1% or more and a surface roughness Ra of 0.05 μm or more. The polarizing plate provided with the optical film of any one of Claims 8-14. An image display device comprising the polarizing plate of claim 15.

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