KR20170020087A - Anti-reflection film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an anti-reflection film, and more particularly, to an anti-reflection film having a plurality of nanostructures formed on at least one surface thereof to form a moth-eye pattern, wherein a shape of the nanostructure is a shape in which the width becomes narrower toward an upper end and a lower end in an intermediate portion, wherein a part of or all of the plurality of nanostructures constituting the moth-eye pattern has a structure in which the intermediate portion is in close contact with an adjacent nanostructure.

Description

TECHNICAL FIELD The present invention relates to an anti-reflection film and a manufacturing method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film using a moth eye structure and a method for manufacturing the same.

Recently, smart devices such as smart phones or tablet PCs have been providing DMB, digital cameras, video calls, and Internet browsing functions. As a result, interest in display quality is steadily increasing. Particularly, since the portable terminal is used in various external light conditions, when the outdoor sunlight or the indoor lighting is reflected on the display surface, it often becomes an important problem that the original screen image can not be seen properly. Accordingly, there is a need to develop a technique for improving the visibility of a display by reducing reflection of various external light generated from the display surface.

For this purpose, a structure that imitates the moth-eye of the natural world has been proposed as a method for reducing the reflection of external light most effectively. The eyes of moths that act at night have nano-protrusions with a diameter of several tens to several hundreds of nanometers protruding from the surface, and the protrusions have a conical, unique nanostructured form so that the refractive index continuously changes in the thickness direction. This continuous change in refractive index essentially eliminates the difference in refractive index, which is the fundamental cause of reflection, so that it is possible to realize an ideal anti-reflection performance in which almost no reflection occurs on the surface.

In the above-mentioned context, Japanese Laid-Open Patent Application No. 2013-190504 discloses a micro concavo-convex shape (moss eye structure) arranged at a period shorter than the wavelength of visible light, and has a shape in which the diameter of each projection becomes larger toward the root Anti-reflection film which improves antireflection performance is disclosed in U.S. Patent Publication No. 2013-0309452, in which an acrylic resin having excellent durability is used as a base material and a sharp-shaped Moshei structure is formed on the base material, Technology.

However, in the case of the antireflection film disclosed in the aforementioned Japanese Patent Laid-Open Nos. 2013-190504 and 2013-0309452, since the upper end portion of the micro projection is sharp, the antireflection performance is excellent, There is a problem in that the durability is weak against the pressure and there is a limit in commercialization.

Therefore, in order to commercialize antireflection film products employing the Moshei structure at the present time, it is necessary to develop an antireflection film technology having excellent antireflection performance and durability that can be commercialized at the same time .

The present invention has been made in view of the above-described needs, and an object of the present invention is to provide an antisoasse anti-reflective film having excellent antireflection performance and durability that can be simultaneously commercialized.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. will be.

In order to achieve the above object,

An antireflection film comprising a plurality of nanostructures formed on at least one surface thereof and forming a moth-eye pattern, characterized in that the shape of the nanostructure is a shape in which a width becomes narrower from an intermediate portion to an upper end portion and a lower end portion And a part or all of the plurality of nanostructures constituting the moth eye pattern are in close contact with the neighboring nanostructure.

According to the present invention, the shape of the nanostructure becomes narrower toward the upper end and the lower end from the intermediate portion, and a part or all of the plurality of nanostructures constituting the moth eye pattern are in close contact with the adjacent nanostructure And is excellent in durability against external impact, and at the same time, antireflection performance as an antireflection film is also excellent.

1 is a side sectional view of an anti-reflection film according to an example of the present invention.
FIG. 2 is a flow chart of the method for producing the antireflection film shown in FIG. 1.
3 is a side cross-sectional view of an anti-reflection film according to another example of the present invention.
FIG. 4 is a flowchart showing a method of manufacturing the antireflection film shown in FIG.
5 is a SEM photograph of the antireflection film according to Example 1 of the present invention.
6 is a SEM photograph of an antireflection film according to Example 2 of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to facilitate an understanding of the present invention. However, the description related to the following drawings is only an example for explaining the present invention, and thus the scope of the present invention is not limited thereto.

One example of the present invention relates to an antireflection film, and more particularly, to an antireflection film having a plurality of nanostructures formed on at least one side thereof to form a moth-eye pattern, wherein the shape of the nanostructure is And a shape in which the width becomes narrower toward the upper end portion and the lower end portion in the intermediate portion.

1, the anti-reflection film 100 includes a substrate layer 110 made of a transparent material, and a light-shielding layer formed on the substrate layer And a nanostructure layer 120 having a plurality of nanostructures formed on its surface to form a moth-eye pattern. The antireflection film 100 has a plurality of nanostructures formed on at least one surface thereof to form a moth-eye pattern. The nanostructure layer 120 on which the Mosey pattern is formed has a base layer 110 may be formed on both sides as well as on both sides.

The base layer 110 of the antireflection film 100 may be formed of a transparent material capable of transmitting light, and may be formed into various shapes such as a plate shape by injection molding, extrusion molding, or cast molding. The base layer 110 may be made of, for example, polyethylene terephthalate (PET), polymethyl methacrylate polymer, polycarbonate, styrene polymer, methyl methacrylate ) -Styrene copolymer, cellulose diacetate, cellulose triacetate, cellulose acetate butylate, polyester, polyamide, polyimide, Polyether sulfone, poly sulfone, polypropylene, poly methyl pentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polyether sulfone, Polyurethane, glass, quartz, etc. may be used.

The base layer 110 is formed on the surface of the nanostructure layer 120 with various coatings or corona discharge treatment for the purpose of improving the adhesion with the curable composition of the nanostructure layer 120 or the antistatic property, Can be performed. In particular, it is preferable that the base layer 110 is made of a material having a small difference in refractive index from the polymer resin composition that is the material of the nanostructure layer 120, in order to improve the antireflection effect.

The thickness of the base layer 110 is not particularly limited, but is preferably 50 to 250 占 퐉 in consideration of durability and antireflection performance of the antireflection film.

In the antireflection film 100, the nanostructure layer 120 is made of a cured product of a curable composition such as a photo-curable resin cured by light energy such as ultraviolet rays or electron beams, or a thermosetting resin cured by heat. However, it is preferable to use a photocurable resin composition in order to reduce the manufacturing cost, Particularly, in the present invention, it is most preferable to use an ultraviolet ray hardening resin composition as a material of the nanostructure layer in order to impart elasticity to the nanostructure among the above-mentioned photocurable resin compositions.

The ultraviolet ray hardening resin composition comprises 30 to 80% by weight of an ultraviolet ray curable compound (monomer) having an unsaturated double bond with respect to the total weight of the composition, 1 to 40% by weight of an ultraviolet ray curable resin (oligomer or polymer), 1 to 10% by weight of a photoinitiator, By weight to 30% by weight, and will be described in more detail as follows.

① UV curable compound (monomer)

In the present invention, the ultraviolet curable compound having an unsaturated double bond is preferably at least one selected from the group consisting of a monomer having a vinyl group, a monomer having a (meth) acryloxy group and a monomer having an allyl group.

Examples of the monomer having a vinyl group include cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, diethylene glycol divinyl Ether, ethylene glycol butyl vinyl ether, ethylene glycol divinyl ether, triethylene glycol methyl vinyl ether, triethylene glycol divinyl ether, trimethylolpropane trivinyl ether, 1,4-cyclohexanedimethanol divinyl ether, vinyl acetate, Vinyl chloroacetate, N-vinylpyrrolidone, N-vinylcarbazole, N-vinylcaprolactam, vinyltoluene, styrene, and alphamethylstyrene.

Examples of the monomer having (meth) acryloxy group include isobornyl acrylate, 1,6-hexanediol diacrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetraethylene glycol di Butanediol diacrylate, 1,4-butanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, neopentyl di (meth) acrylate, (Meth) acrylate, polyethylene glycol di (meth) acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, alkoxylated tetraacrylate, octyldecyl acrylate, isodecyl acrylate, Lauryl acrylate, stearyl acrylate, behenyl acrylate, and the like.

Examples of the monomer having allyl group include allyl propyl ether, allyl butyl ether, allyl ether, pentaerythritol triallyl ether, diphenic acid diaryl, trimethylol propane diallyl ether, trimethylol propane triallyl ether, diallyl phthalate, Phthalate, triallyl trimellitate and the like.

The content of the entire ultraviolet curable compound in the composition is preferably 30 to 80% by weight.

According to a preferred embodiment of the present invention, the ultraviolet curable compound may be a mixture of a bifunctional methacrylate monomer, a trifunctional methacrylate monomer and a pentafunctional methacrylate monomer, Based on 20 to 60% by weight of bifunctional methacrylate monomers, 5 to 40% by weight of trifunctional methacrylate monomers and 1 to 40% by weight of pentafunctional methacrylate monomers.

② Ultraviolet curable resin (oligomer or polymer)

In the present invention, the ultraviolet curable resin means an ultraviolet curable resin having at least one functional group selected from a vinyl group, a (meth) acryloxy group, an allyl group and an allyloxy group.

The ultraviolet curable resin is preferably an oligomer or polymer having a molecular weight of 1000 or more. Specific examples thereof include cycloaliphatic or aromatic urethane acrylate oligomers having at least two reactive functional groups, polyester (meth) acryl (Meth) acrylate, epoxy (meth) acrylate or polycarbonate (meth) acrylate oligomer, or mixtures thereof.

The content of the ultraviolet curable resin having the functional group is preferably 1 to 40% by weight based on the total weight of the composition. This is because, when it exceeds this range, the compactness of the cured coating film is lowered, so that the heat resistance of the cured product is deteriorated due to the lowering of the glass transition temperature (Tg), and the durability of the cured coating film may be significantly lowered.

③ Photo initiator

In the present invention, the photoinitiator is preferably a compound which generates a free radical or a cation by ultraviolet rays. Examples of the free radical initiator include benzyl ketaldehyde, benzoin ethers, acetophenone derivatives, ketoxime ethers, benzophenone, benzo or thioxanthone compounds, and the cationic initiators include onium salts, Ferrocenium salts, or diazonium salts.

④ Slip agent

In the present invention, the slip agent is added for controlling the releasability, and it is preferable that the slip agent contains 10 to 30% by weight, based on the total weight of the composition, of a compound having a silicon group or a fluorine group or both a silicon group and a fluorine group.

The compound having both the silicon group and the fluorine group or both the silicon group and the fluorine group may also be a UV-curable compound such as a vinyl group, a (meth) acrylate group or an allyl group, a surfactant or an oil. (Meth) acryloxy group-containing organosiloxane, silicone polyether acrylate, fluoroalkyl group-containing vinyl compound, fluoroalkyl group-containing (meth) acrylate compound, Acrylate compounds, fluoropolyacrylates, polydimethylsiloxanes, fluoropolymers, dimethylsilicone oils and the like.

The shape of the nanostructure formed on the nanostructure layer is a shape in which the width becomes narrower toward the upper end and the lower end from the middle portion. Referring to the example shown in FIG. 1, And the width of the nanostructure is smaller toward the upper end 121 and the lower end 123 of the intermediate portion 122 than the upper end 121 and the lower end 123. [

In the anti-reflection film, the shape of the nanostructure is larger than that of the upper end and lower end of the nanostructure, and the width gradually decreases from the intermediate portion to the upper end and the lower end. Thus, even when an external impact is applied to the nanostructure, The stress due to the external impact and the stress against the external shock are dispersed after being concentrated at the midpoint of the thickest nano structure, so that there is an advantage that the impact can be effectively mitigated. Thus, the width from the upper end to the lower end There is an effect of being more durable than an antireflection film comprising a nanostructure having a gradually increasing shape (ex: tapered shape).

The shape of the side portion is not particularly limited as long as the width of the side portion is narrower toward the upper and lower ends of the nano structure. However, it is preferable that the shape of the side portion is round as in the example shown in FIG. This is because when the shape of the side portion is round, the nanostructure itself has the highest elasticity in structure, and thus, when external impact is applied, the nanostructure can minimize the damage of the shape of the nanostructure due to the self- This is because.

In addition, although the shape of the upper end portion of the nanostructure is not particularly limited, the nanostructure may be formed to have high durability against external impact and minimized deterioration of antireflection performance, It is preferable that it has a round shape as in the example shown in Fig. 1 rather than a planar shape or a sharp shape.

In order to minimize the reflectance of light in the visible light wavelength region and also to meet the high durability of the nanostructure, the width of the interstice may be set to a range of 40 to 100 nm and a height of 80 to 320 nm.

The nanostructures are advantageous in that they have a certain level of elasticity in terms of improvement in impact resistance and durability. The bulk modulus of the nanostructures varies depending on the materials used and is not particularly limited. However, It is preferable that the volume elastic modulus of the nanostructure is in the range of 10 ⁹ Pa to 10 ¹⁰ Pa so that the shape of the nanostructure can be restored and maintained by the self-restoring force.

The anti-reflection film has a shape in which the shape of the nanostructure becomes narrower toward the upper end and the lower end from the intermediate portion, so that the anti-reflection film has excellent durability against external impact and also has an excellent antireflection performance as an antireflection film. The reflectance of the antireflection film is not particularly limited, but is preferably 1% or less in consideration of optimum visibility of the display.

The method of manufacturing the antireflection film is preferably a nanoimprint process in which a nano pattern is transferred using a mold having a plurality of nano pores formed on its surface in consideration of a manufacturing process efficiency for mass production, no. FIG. 2 is a flow chart of a method for producing an antireflection film using a nanoimprint process as an example of a method for manufacturing an antireflection film of the present invention. Referring to FIG. 2, As follows.

Referring to FIG. 2, the method for fabricating the antireflection film according to the present invention includes the steps of preparing a mold having a plurality of nano pores formed on a surface thereof with a space spacing of 1/3 or more of the pore diameters (S10); (S11) of applying an ultraviolet curing resin composition to one side of the base film; (S12) transferring a plurality of nanostructures corresponding to the nano pores of the mold to the ultraviolet ray hardening resin composition by bringing the base film coated with the ultraviolet ray hardening resin composition and the mold having the plurality of nano pores into contact with each other; A primary curing step (S13) of partially curing the UV curable resin composition by irradiating the base film with ultraviolet light before mold releasing; And a step (S14) of releasing the mold from the substrate film after the primary curing and further secondary irradiation with ultraviolet light to secondary cure the ultraviolet curable resin composition until it is completely cured.

The step of preparing the mold (S10) may be either a hard mold or a soft mold, and a plurality of nano pores are formed on the surface of the mold. The hard mold may be formed by forming a plurality of nano-pores by anodizing the surface of a flat or rolled aluminum substrate, but is not limited thereto. The soft mold is typically made of a resin composition material and has a plurality of nano pores formed on the surface of the resin layer in the form of a sheet. The hard mold (master mold) And may be one produced by transferring a plurality of nano pores to the surface.

The interval of the nanopores formed in the mold is not particularly limited, but it is necessary to maintain a minimum gap between the nanostructures in order to prevent sticking between the nanostructures after UV curing in a subsequent process step. For this purpose, It is preferable that the space interval of the nano pores formed in the mold is 1/3 or more of the pore diameter.

The step (S11) of applying the ultraviolet ray hardening resin composition to one side of the base film forms a coating layer of the ultraviolet ray hardening resin composition on one side of the base film. The thickness of the coating layer of the ultraviolet ray hardening resin composition is not particularly limited, But it is preferably 3 to 7 占 퐉 in order to keep the reflectance of visible light region versus light as low as possible.

The step (S12) of transferring a plurality of nanostructures corresponding to the nano pores of the mold to the ultraviolet ray hardening resin composition can be applied to any nanoimprint method. However, in order to maximize the mass production efficiency of the antireflection film, .

The step (S13) of primary curing the ultraviolet ray hardening resin composition is a step of partially curing the ultraviolet ray hardening resin composition by irradiating the base film with ultraviolet rays before mold release, The width of the intermediate portion is larger than that of the upper and lower ends due to the viscosity of the cylindrical nanostructure transferred to the ultraviolet ray hardening resin composition by the stop of the ultraviolet ray irradiation and the release of the base film from the mold, The nanostructure having a part can be temporarily formed. In the ultraviolet primary irradiation, an exposure amount of 70 to 150 mJ / cm ² is preferable from the viewpoint of preventing the deterioration of releasability while maintaining an appropriate viscosity of the nanostructure.

In the step of hardening the ultraviolet ray hardening resin composition (S14), the ultraviolet ray hardening resin composition having the protruded nano structure formed at the intermediate portion through the immediately preceding step (S13) is immersed It irradiates ultraviolet rays. The ultraviolet secondary irradiation preferably has an exposure dose of 1000 to 2000 mJ / cm ² for sufficient curing of the ultraviolet ray hardening resin composition, and the shape of the nanostructure is changed from a convex shape to a recessed shape, It is preferable that the time is between 5 seconds and 5 minutes after the primary curing is performed.

Another example of the present invention relates to an antireflection film, and more particularly, to an antireflection film having a plurality of nanostructures formed on at least one surface thereof to form a moth-eye pattern, wherein the shape of the nanostructure is And a part of or all of the plurality of nanostructures constituting the morse eye pattern are in close contact with the neighboring nanostructure.

3, the anti-reflection film 200 includes a substrate layer 210 made of a transparent material, and an anti-reflection film formed on the substrate layer And a nanostructure layer 220 having a plurality of nanostructures formed on its surface to form a moth-eye pattern. The antireflection film 200 has a plurality of nanostructures formed on at least one surface thereof to form a moth-eye pattern. The nanostructure layer 220 on which the Mos-eye pattern is formed has a base layer 210 may be formed on both sides as well as on both sides.

The base layer 210 of the antireflection film 200 is formed of a transparent material capable of transmitting light, and may be formed in various shapes such as a plate shape by injection molding, extrusion molding, or cast molding. The base layer 210 may be formed of, for example, a polymethyl methacrylate polymer, a polycarbonate, a styrene polymer, a methyl methacrylate-styrene copolymer, a cellulose Cellulose diacetate, cellulose triacetate, cellulose acetate butylate, polyester, polyamide, polyimide, polyether sulfone, polyether sulfone, Polypropylene, poly methyl pentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polyurethane, glass, and the like. , Modification, etc., may be used.

The substrate layer 210 may be coated with various coatings or corona discharge treatment to improve the adhesion to the curable composition of the nanostructure layer 220 or to improve the antistatic property, Can be performed. Particularly, it is preferable that the base layer 210 is made of a material having a small difference in refractive index from the polymer resin composition which is the material of the nanostructure layer 220, in order to improve the antireflection effect.

The thickness of the base layer 210 is not particularly limited, but is preferably 50 to 250 占 퐉 in consideration of durability and antireflection performance of the antireflection film.

The nano structure layer 220 of the antireflection film 200 may be a curable composition such as a photo-curable resin that is cured by light energy such as ultraviolet rays or electron beams, or a thermosetting resin that is cured by heat. However, it is preferable to use a photocurable resin composition in order to reduce the manufacturing cost. In the present invention, among the photocurable resin compositions, an ultraviolet curing resin composition is used as a material of the nanostructure layer in order to impart elasticity to the nanostructure . Since the ultraviolet ray hardening resin composition is the same as that described above, a detailed description thereof will be omitted.

The shape of the nanostructure formed in the nanostructure layer is a shape in which the width of the nanostructure is reduced toward the upper end and the lower end in the middle portion. Referring to the example shown in FIG. 3, And the width of the nanostructure decreases from the intermediate portion 222 toward the upper end 221 and the lower end 223. The width of the nanostructure is smaller than that of the upper portion 221 and the lower end 223.

In addition, the anti-reflection film 200 is formed in a structure in which a part or all of a plurality of nanostructures constituting the Moissy pattern closely contact with the adjacent nanostructure 222, 3, the intermediate portion 222 of the nanostructure is in close contact with the intermediate portion of the adjacent nanostructure. Referring to FIG. 3, the antireflection film 200 according to another exemplary embodiment of the present invention includes the intermediate portion 222, There are 5 nano structures in close contact with each other, and they are grouped into 3 groups and 2 groups.

The shape of the nanostructure is larger than the upper end and lower end of the nanostructure, and the width of the nanostructure gradually decreases from the middle to the upper end and the lower end. Thus, even if an external impact is applied to the nanostructure, And the stress due to the pressure is concentrated at the center of the nano structure having the thickest thickness and then dispersed, so that the impact can be effectively mitigated. Accordingly, the shape having a gradually increasing width from the upper end portion to the lower end portion (ex : Tapered shape) than the anti-radiation material containing the nanostructure.

In addition, since the interstices of the nanostructures are in close contact with the interstices of the adjacent nanostructures, each of the nanostructures attached to the adjacent nanostructures supports the adjacent nanostructure, so that the durability can be further enhanced , The nano structure is closely contacted with the interstices, and the upper part of the nano structure still forms independent projections with respect to each of the closely attached nanostructures. Therefore, the reflectance can be secured much lower than the structure in which the upper part of the existing nanostructure is closely attached .

The shape of the side portion is not particularly limited as long as the width of the nanostructure is narrowed toward the upper end and the lower end from the intermediate portion. However, it is preferable that the shape of the side portion is round as in the example shown in FIG. This is because when the shape of the side portion is round, the nanostructure itself has the highest elasticity in structure, and thus, when external impact is applied, the nanostructure can minimize the damage of the shape of the nanostructure due to the self- This is because.

In addition, although the shape of the upper end portion of the nanostructure is not particularly limited, the nanostructure may be formed to have high durability against external impact and minimized deterioration of antireflection performance, It is preferable that it has a round shape as in the example shown in Fig. 3 rather than a planar shape or a sharp shape.

In order to minimize the reflectance of light in the visible light wavelength region and also to meet the high durability of the nanostructure, the width of the interstice may be set to a range of 40 to 100 nm and a height of 80 to 320 nm.

The nanostructures are advantageous in that they have a certain level of elasticity in terms of improvement in impact resistance and durability. The bulk modulus of the nanostructures varies depending on the materials used and is not particularly limited. However, It is preferable that the volume elastic modulus of the nanostructure is in the range of 10 ⁹ Pa to 10 ¹⁰ Pa so that the shape of the nanostructure can be restored and maintained by the self-restoring force.

The anti-reflection film according to another exemplary embodiment of the present invention has a shape in which the shape of the nanostructure becomes narrower toward the upper end and the lower end from the intermediate portion, and a part or all of the plurality of nanostructures constituting the Mos- It is formed in a structure in which the structure is closely adhered to each other so that it has excellent durability against external impact and also has an excellent antireflection performance as an antireflection film. The reflectance of the antireflection film is not particularly limited, but is preferably 1% or less in consideration of optimum visibility of the display.

A method for producing the antireflection film will be described below.

The method of manufacturing the antireflection film is preferably a nanoimprint process in which a nano pattern is transferred using a mold having a plurality of nano pores formed on its surface in consideration of a manufacturing process efficiency for mass production, no. 4 is a flowchart illustrating a method of manufacturing an antireflection film using the nanoimprint process as an example of the method of manufacturing the antireflection film of the present invention. Referring to FIG. 4, As follows.

Referring to FIG. 4, the method for fabricating the antireflection film according to the present invention includes the steps of preparing a mold having all or a part of a plurality of nano pores formed on a surface thereof at intervals of less than 1/3 of the pore diameter (S20) ; A step (S21) of applying an ultraviolet curable resin composition to one side of the base film; (S22) transferring a plurality of nanostructures corresponding to the nano pores of the mold to the ultraviolet ray hardening resin composition by bringing the base film coated with the ultraviolet ray hardening resin composition and the mold having the plurality of nanopores into contact with each other; A first curing step (S23) of partially curing the ultraviolet-curable resin composition by irradiating the base film with ultraviolet light before mold release; And a step (S24) of releasing the mold from the substrate film after the primary curing and further secondary irradiation with ultraviolet light to secondary cure the ultraviolet curable resin composition until it is completely cured.

The step of preparing the mold (S20) may be a hard mold or a soft mold, and a plurality of nano pores are formed on the surface of the mold. The hard mold may be formed by forming a plurality of nano-pores by anodizing the surface of a flat or rolled aluminum substrate, but is not limited thereto. The soft mold is typically made of a resin composition material and has a plurality of nano pores formed on the surface of the resin layer in the form of a sheet. The hard mold (master mold) And may be one produced by transferring a plurality of nano pores to the surface.

The gap of the nanopores formed in the mold is not particularly limited. However, the nanostructure formed on the nanostructure layer after UV curing in a subsequent process step has a structure in which a part or whole of the nanostructure closely contacts the adjacent nanostructure It is preferable that all or part of the nano pores formed in the mold have a space space less than 1/3 of the pore diameter .

The step (S21) of applying the ultraviolet ray hardening resin composition to one side of the base film forms a coating layer of the ultraviolet ray hardening resin composition on one side of the base film. The thickness of the coating layer of the ultraviolet ray hardening resin composition is not particularly limited, But it is preferably 3 to 7 占 퐉 in order to keep the reflectance of visible light region versus light as low as possible.

Although any nanoimprint method can be applied to the step (S22) of transferring a plurality of nanostructures corresponding to the nano pores of the mold to the ultraviolet ray hardening resin composition, in order to maximize the mass production efficiency of the antireflection film, a roll- .

The step (S23) of curing the ultraviolet ray hardening resin composition is a step of partially curing the ultraviolet ray hardening resin composition by irradiating the base film with ultraviolet rays before mold release, The width of the intermediate portion is larger than that of the upper and lower ends due to the viscosity of the cylindrical nanostructure transferred to the ultraviolet ray hardening resin composition by the stop of the ultraviolet ray irradiation and the release of the base film from the mold, The nanostructure having a part can be temporarily formed. In the ultraviolet primary irradiation, the exposure dose is 70 to 150 mJ / cm ² Is preferable in terms of preventing excessive deterioration of the releasability while maintaining an appropriate viscosity of the nanostructure.

In the second curing step (S24) of the ultraviolet ray hardening resin composition, the ultraviolet ray hardening resin composition having the convex shaped nanostructure formed through the preceding step (S23) is immersed in the ultraviolet ray hardening resin composition It irradiates ultraviolet rays. The ultraviolet secondary irradiation preferably has an exposure dose of 1000 to 2000 mJ / cm ² for sufficient curing of the ultraviolet ray hardening resin composition, and the shape of the nanostructure is changed from a convex shape to a recessed shape, It is preferable that the time is between 5 seconds and 5 minutes after the primary curing is performed.

Hereinafter, the present invention will be described by way of examples. The following examples are only illustrative of the present invention, and the scope of the present invention is not limited thereby.

<Examples>

Example 1: Preparation of an antireflection film comprising a nanostructure of a convex shape in the intermediate portion

First, an aluminum roll mold in which a plurality of columnar nano pores (pore average diameter: 60 nm, average height: 120 nm) are formed on the surface is prepared (the space space of the nano pores is 1/2 or more of the pore diameter) , And a transparent base material film (thickness 188 占 퐉) made of polyethylene terephthalate (PET). The ultraviolet curable resin composition was applied to a thickness of 5 占 퐉. The composition of the ultraviolet ray hardening resin composition was such that 25% by weight of a bifunctional methacrylate monomer (1,4-butadiene dimethacrylate), 10% by weight of a trifunctional methacrylate monomer (trimethylolpropane trimethacrylate) 10 5% by weight of a polyfunctional methacrylate monomer (dipentaerythritol pentaacrylate), 25% by weight of a urethane acrylate oligomer, 10% by weight of an epoxy acrylate oligomer, 5% by weight of benzophenone, 20% by weight of polydimethylsiloxane, to be.

The base film coated with the ultraviolet ray hardening resin composition is brought into pressure contact with the aluminum roll mold and the sub roll prepared in the above manner while being passed between the aluminum roll mold and the sub roll in a rolling manner, Was first irradiated (100 mJ / cm &lt; ² &gt;) to primary cure to the extent that the viscosity of the ultraviolet ray hardening resin composition remained to some extent.

The base film is released from the roll mold After the curing for 2 minutes, ultraviolet rays were irradiated (1500 mJ / cm ² ) and the secondary curing proceeded until the ultraviolet ray hardening resin composition was sufficiently cured to prepare an antireflection film.

SEM photographs of the antireflection film prepared in Example 1 are shown in FIG. 5, and it can be seen that a nanostructure is formed in the nanostructure layer of the antireflection film as shown in FIG. 5 .

Example 2: An antireflection film having a structure in which interstices between nanostructures are closely adhered

A plurality of pillar-shaped nano pores (pore average diameter: 60 nm, average height: 100 nm) are formed on the surface, and a part of the nano pores is formed at a space interval of less than 1/3 of the pore diameter An antireflection film was produced by the same process and under the same conditions as in Example 1 above.

The SEM photograph of the anti-reflection film prepared in Example 2 is shown in FIG. 6. As shown in FIG. 6, the nanostructure of the antireflection film is formed in the nanostructure layer of the antireflection film, It can be confirmed that the adjacent nanostructures are in close contact with each other.

Comparative Example: An antireflection film having a cylindrical nano structure

As a comparative example according to the present invention, the same roll mold and the base film coated with the ultraviolet ray hardening resin composition as in Example 1 were used, and the base film coated with the ultraviolet ray hardening resin composition was rolled between the aluminum roll mold and the sub roll (2000 mJ / cm &lt; ² &gt;) from the time immediately before the substrate film was contacted with the aluminum roll mold to release the ultraviolet ray, and the curing was continued until the ultraviolet ray hardening resin composition was completely cured , The base film was released from the mold to produce an antireflection film having a columnar nanostructure having substantially the same width as the upper end portion, the intermediate portion and the lower end portion.

Experimental Example 1: Evaluation of durability

The surface of each of the antireflection films produced in Examples 1 and 2 and Comparative Example was visually inspected for the occurrence of damage after rubbing and rubbing the surface of the antireflection film 5,000 times at a surface pressure of 392 Pa. Durability was evaluated as &quot; x &quot;, and &quot; o &quot; where no occurrence was recognized. The results are shown in Table 1 below.

As shown in Table 1, it can be confirmed that the antireflection films of Examples 1 and 2 according to the present invention have higher durability than the conventional antireflection film.

Experimental Example 2: Evaluation of reflectance

Each of the antireflection films prepared in Examples 1 and 2 and Comparative Example was irradiated with visible light having a wavelength of 555 nm and the reflectance at an incident angle of 0 degree and a measurement angle of 0 was measured to evaluate the antireflection performance , And the results are shown in Table 1 below.

Table 1 shows that the antireflection film of Example 1 (reflectance: 0.62%) and Example 2 (reflectance: 0.80%) according to the present invention had significantly lower reflectance than the comparative example (reflectance: 1.20% It can be seen that the antireflection performance of Examples 1 and 2 according to the present invention is much better.

division
Performance test durability reflectivity(%) Example 1 ○ 0.62 Example 2 ○ 0.80 Comparative Example × 1.20

As described above, those skilled in the art will understand that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It will be understood by those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention as defined by the appended claims and their equivalents. .

100, 200: antireflection film 110, 210: substrate layer
120, 220: nano structure layer 121, 221: nano structure upper part
122 and 222: nano structure interrupter 123 and 223: nano structure lower part

Claims (12)

An antireflection film comprising a plurality of nanostructures formed on at least one side thereof to form a moth-eye pattern,
The shape of the nanostructure is a shape in which the width of the nanostructure decreases from the intermediate portion to the upper end portion and the lower end portion,
Wherein some or all of the plurality of nanostructures constituting the morse eye pattern are in close contact with the neighboring nanostructure.
The method according to claim 1,
Wherein the nanostructure has a rounded side surface.
The method according to claim 1,
Wherein the nanostructure has an upper end rounded.
The method according to claim 1,
Wherein the nanostructure has a width of the intermediate portion of 40 to 100 nm and a height of 80 to 320 nm.
The method according to claim 1,
Wherein the nanostructure has a bulk modulus of from 10 ⁹ Pa to 10 ¹⁰ Pa.
The method according to claim 1,
Wherein the reflectance is 1% or less.
Preparing a mold in which all or a part of a plurality of nano pores formed on the surface are formed at a space interval less than 1/3 of the pore diameter;
Applying an ultraviolet curable resin composition to one surface of a base film;
Transferring a plurality of nanostructures corresponding to nano pores of the mold to the ultraviolet ray hardening resin composition by bringing the base film coated with the ultraviolet ray hardening resin composition and the mold having the plurality of nano pores into contact with each other;
A primary curing step of partially curing the UV curable resin composition by irradiating the base film with ultraviolet light before mold release; And
And curing the ultraviolet curing resin composition to a second curing state until the ultraviolet curing resin composition is completely cured after releasing the mold from the base film after the first curing.
8. The method of claim 7,
Wherein the step of applying the ultraviolet-curable resin composition to one surface of the base film is applied in a thickness of 3 to 7 占 퐉.
8. The method of claim 7,
Wherein the step of transferring the plurality of nanostructures corresponding to the nanopores of the mold to the ultraviolet ray hardening resin composition uses a roll-to-roll method.
8. The method of claim 7,
The primary curing step may be performed at an exposure amount of 70 to 150 mJ / cm &lt; ² &gt; Wherein the antireflection film has a thickness of 100 nm or less.
8. The method of claim 7,
Wherein the second curing step has an exposure dose of 1,000 to 2,000 mJ / cm ² upon ultraviolet irradiation.
8. The method of claim 7,
Wherein the second curing step comprises irradiating ultraviolet light for 5 seconds to 5 minutes after the primary curing is performed.

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