JP2012003074A - Optical film and optical device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film for light extraction, with both optical performance and mechanical performance improved.SOLUTION: A rugged structural part 12 of an optical film having a transparent base material film 14 and a rugged structural part 12 comprises an active energy ray-curable resin containing the following (A) a component, (B) a component and (C) a component: (A) a urethane (meth)acrylate compound containing at least one kind of urethane (meth)acrylate compound having three or more (meth)acryloyl groups in the molecule, (B) a di(meth)acrylate compound having no urethane bond and two (meth)acryloyl groups in the molecule, and (C) a radical photoinitiator. The rugged structural part 12 has a rugged structure formed on one side thereof. The surface on the rugged structure side of the rugged structural part 12 has a shape where a rugged unit shape 12a is repeatedly aligned along the surface on the rugged structure side.

Description

  The present invention relates to an optical film, and more particularly to an optical film that contributes to an improvement in the extraction efficiency of light emitted from an optical device in an optical device such as a lighting device or a display device, and an optical device using the optical film. It is.

  As a surface emitting device capable of being thinned, a device using an electroluminescent (EL) element has been proposed. In order to increase the efficiency of light emission by the EL element, it is necessary to efficiently extract light emitted from the light emitting layer in the EL element and traveling to the transparent base material through the transparent electrode from the surface of the transparent base material.

  In order to improve the light extraction efficiency of such an EL element, it has been proposed to provide a sheet having a concavo-convex structure on the surface of the transparent substrate of the EL element (see Patent Document 1 and Patent Document 2).

  Patent Document 3 describes a sheet-like optical article made of an active energy ray-curable resin.

JP 2003-59641 A WO2004 / 017106 WO2006 / 041089

  Patent Document 1 does not particularly describe the material of a sheet having a concavo-convex structure surface for extracting light. In addition, Patent Document 2 discloses a material having a concavo-convex structure surface for extracting light as a chain polyolefin resin, an aromatic vinyl resin, an alicyclic olefin resin, a polyester resin, an acrylic resin, an acrylonitrile resin, Polyether resins and ketone resins are mentioned, and chain polyolefin resins, alicyclic olefin resins and polyether resins are particularly preferred.

  By the way, with respect to an optical film that contributes to an improvement in the extraction efficiency of light emitted from an optical device such as an EL element that emits isotropic light whose emission distribution is substantially independent of the direction in the light emitting surface, the light extraction efficiency thereof In addition to the improvement in optical performance such as the above, it is required to improve the mechanical performance, in particular, the durability (scratch resistance) against contact or scratching of foreign matter. However, Patent Documents 1 and 2 have no description regarding improvement of the mechanical performance of the sheet.

  Patent Document 3 does not describe a sheet-like optical article applied to an optical device such as an isotropic light-emitting EL element.

  The object of the present invention is to apply to the optical device for isotropic light emission as described above, in view of the technical problem in the optical film (optical film for light extraction) that contributes to the improvement of the light extraction efficiency. It is an object of the present invention to provide an optical film for light extraction with further improved performance. Another object of the present invention is to provide an optical device using the optical film for light extraction as described above.

According to the present invention, to achieve any of the above objects,
An optical film having an uneven structure part,
The concavo-convex structure portion includes the following components (A), (B) and (C):
(A) a urethane (meth) acrylate compound containing at least one urethane (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule;
(B) a di (meth) acrylate compound having no urethane bond in the molecule and having two (meth) acryloyl groups,
(C) a radical photopolymerization initiator,
An active energy ray-curable resin containing
The concavo-convex structure portion has a concavo-convex structure formed on one surface,
The surface of the concavo-convex structure portion of the concavo-convex structure portion has a shape formed by repeatedly arranging concavo-convex unit shapes in at least one direction along the surface of the concavo-convex structure side,
Is provided.

  In one aspect of the present invention, the concavo-convex unit shape is roughly a pyramid shape, a truncated pyramid shape, a conical shape, a truncated cone shape, a roof shape, a hemispherical shape, or a hemispherical shape, and forms a protrusion or a depression. . In one aspect of the present invention, the optical film further includes a transparent substrate film bonded to a surface opposite to the surface of the concavo-convex structure portion on the concavo-convex structure side.

Further, according to the present invention, to achieve any of the above objects,
The optical film, and an optical device that is located on the opposite side of the surface of the concavo-convex structure portion of the concavo-convex structure portion, and is bonded to the surface of the optical film,
An optical device characterized in that light emitted from the optical device is emitted from the surface of the concavo-convex structure portion of the optical film on the concavo-convex structure side;
Is provided.

  According to the present invention as described above, an optical film for light extraction capable of improving both optical performance such as light extraction efficiency and mechanical performance such as scratch resistance by applying to an isotropic light emitting optical device, And an optical apparatus using the same.

It is a schematic diagram which shows one Embodiment of the optical film by this invention, and an optical apparatus using the same. It is a figure which shows the specific example of the uneven | corrugated unit shape of an uneven | corrugated structure part. It is a figure which shows the specific example of the uneven | corrugated unit shape of an uneven | corrugated structure part. It is a figure which shows the specific example of the uneven | corrugated unit shape of an uneven | corrugated structure part. It is a figure which shows the specific example of the uneven | corrugated unit shape of an uneven | corrugated structure part. It is a figure which shows the specific example of the uneven | corrugated unit shape of an uneven | corrugated structure part. It is a schematic diagram which shows the manufacturing apparatus of an optical film.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing one embodiment of an optical film according to the present invention and an optical apparatus using the same.

  The optical apparatus according to this embodiment includes an optical film 1 and an optical device 2. The optical device 2 is a known organic EL light emitting element, and is formed by laminating a transparent base layer 22, a transparent electrode layer 24, an organic light emitting layer 26, and a metal electrode layer 28 in this order. FIG. 1 shows an example of an organic EL light-emitting element having a bottom emission structure, but an organic EL light-emitting element having a top emission structure can also be used in the present invention.

  The optical film 1 has a layered concavo-convex structure portion 12 and a transparent substrate film 14 bonded to the concavo-convex structure portion 12. The concavo-convex structure part 12 consists of specific active energy ray hardening resin which is mentioned later.

  The uneven structure portion 12 has an uneven structure formed on one surface (the upper surface in FIG. 1). The surface on the concavo-convex structure side has a shape in which the concavo-convex unit shape 12a is repeatedly arranged in at least two directions along the upper surface. Examples of the unit shape 12a are generally a pyramid shape, a truncated pyramid shape, a conical shape, a truncated cone shape, a roof shape, a hemispherical shape, or a hemispherical trapezoid shape, and those having protrusions or depressions are exemplified. Here, “substantially” with respect to the unit shape 12a is not necessarily limited to geometrically strict shapes, and the entire shape may be deviated from the geometrically strict shape, or a portion. This means that there may be a deformation from a geometrically exact shape. The dimensions of the unit shape 12a are not particularly limited, and examples thereof include those having a height of 10 to 1000 μm and a base dimension of 10 to 1000 μm. When the surface of the unit shape 12a is a flat surface such as a pyramid shape, a truncated pyramid shape, a cone shape, a truncated cone shape, and a roof shape, the angle (base angle) between the surface of the unit shape 12a and the base surface is, for example, It is 20-70 degrees. When the surface of the unit shape 12a is a curved surface such as a hemispherical shape or a hemispherical trapezoidal shape, one side of the vertical cross-sectional shape of the unit shape 12a (that is, the shape of the cross section passing through the layer thickness direction of the concavo-convex structure portion 12). When the curve is approximated by a straight line by linear approximation, the angle formed by the straight line and the base surface is defined as a base angle. This base angle is, for example, 20 to 70 °.

  The thickness of the concavo-convex structure portion 12 is, for example, 10 to 2000 μm.

  2 to 6 show specific examples of the unit shape 12a. FIG. 2 shows an electron microscope (SEM) photograph of an example in which the unit shape 12a is a roof shape (or tent shape). Here, the unit shapes 12a are repeatedly arranged in two directions orthogonal to each other along the concavo-convex structure portion layer. FIG. 3 shows an electron microscope (SEM) photograph of an example in which the unit shape 12a is a triangular pyramid shape. Here, the unit shapes 12a are repeatedly arranged in three directions intersecting with each other at 60 ° along the concavo-convex structure portion layer (however, the direction of the unit shape is alternately inverted in each direction). FIG. 4 shows a 3D laser micrograph of an example in which the unit shape 12a is a hemispherical shape. Here, the unit shapes 12a are repeatedly arranged in three directions intersecting each other at 60 ° along the concavo-convex structure portion layer. FIG. 5 shows a 3D laser microscope photograph of an example in which the unit shape 12a is a quadrangular frustum shape. Here, the unit shapes 12a are repeatedly arranged in two directions orthogonal to each other along the concavo-convex structure portion layer. FIG. 6 shows a laser micrograph of an example in which the unit shape 12a is a quadrangular pyramid shape. Here, the unit shapes 12a are repeatedly arranged in two directions orthogonal to each other along the concavo-convex structure portion layer.

  It is preferable that the concave and convex unit shapes 12a are arranged as close as possible to each other adjacent to each other. That is, it is preferable that the pitch of the repeated arrangement is equal to or slightly larger than the base dimension of the uneven unit shape 12a in the arrangement direction.

  The concavo-convex unit shape 12a as described above may be a protrusion or may be a depression.

  The transparent substrate film 14 is bonded to the surface on the opposite side of the surface on which the concavo-convex unit shape 12a of the concavo-convex structure portion 12 is formed. Therefore, in the optical apparatus of this embodiment, the optical device 2 is bonded to the surface of the optical film 1 located on the opposite side of the surface on which the concavo-convex unit shape 12a of the concavo-convex structure portion 12 is formed.

  In the optical film 1, the transparent base film 14 may be omitted when the shape can be maintained only by the concavo-convex structure portion 12.

  Since the distribution of the light emitted from the optical device 2 is substantially isotropic, the light emitted from the optical device 2 is highly efficient due to the surface on which the concavo-convex unit shape 12a of the concavo-convex structure portion 12 of the optical film 1 is formed. It is taken out with.

Now, the concavo-convex structure portion 12 of the optical film 1 includes the following components (A), (B) and (C):
(A) a urethane (meth) acrylate compound containing at least one urethane (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule;
(B) a di (meth) acrylate compound having no urethane bond in the molecule and having two (meth) acryloyl groups,
(C) a radical photopolymerization initiator,
An active energy ray-curable resin containing

  This resin may further contain (D) a compound having one polymerizable double bond group in the molecule, and (E) other components.

  Such an active energy ray-curable resin is described in Patent Document 3 described above. Hereinafter, each component will be described. In the following, the resin may be described as a resin composition.

(A) Urethane (meth) acrylate compound:
The component (A) used in the resin composition of the present invention is a compound containing at least one urethane (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule. This component (A) is a component that causes a polymerization reaction or a crosslinking reaction by irradiating active energy rays such as ultraviolet rays in the presence of a radical polymerizable photopolymerization initiator, and is mainly an optical film (sheet-like optical article). Imparts scratch resistance and heat resistance to the concavo-convex structure. (A) component should just contain 1 or more types of urethane (meth) acrylate compounds which have 3 or more (meth) acryloyl groups in a molecule | numerator, and 1 or 2 (meth) acryloyl groups in a molecule | numerator It may also contain a urethane (meth) acrylate compound having

  The urethane (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule is typically a polyisocyanate compound having two or more isocyanate groups in the molecule, and one or more in the molecule. It is a compound obtained by making it react with 1 or more types of the (meth) acryloyl compound which has (meth) acryloyl group of this, and has a hydroxyl group. As the polyisocyanate compound having two or more isocyanate groups in the molecule, various polyisocyanate compounds classified into aliphatic, alicyclic, and aromatic groups can be used. In consideration of colorability at the time of curing, light yellowing resistance of the cured product, and the like, isophorone diisocyanate, hexamethylene diisocyanate and trimers thereof (adduct type, biuret type or isocyanurate type) are preferable. Among these, isophorone diisocyanate and isocyanurate-type hexamethylene diisocyanate trimer are more preferable in terms of scratch resistance and heat resistance of the obtained cured product.

  There is no restriction | limiting in particular as a (meth) acryloyl compound which has a 1 or more (meth) acryloyl group in a molecule | numerator, and has a hydroxyl group. For example, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-hydroxy-1-acryloyloxy -3-Methacryloyloxypropane and the like. Here, the acrylate compound is more preferable than the methacrylate compound in terms of photocurability.

  Two or more of the polyisocyanate compound and the (meth) acryloyl compound having a hydroxyl group can be used in combination. By changing the type and ratio of the combination, it is possible to develop an elastic modulus and other physical properties different from those of the urethane (meth) acrylate compound obtained from one type.

  The urethanization reaction between the polyisocyanate compound and the (meth) acryloyl compound having a hydroxyl group can be carried out according to a conventional method. For example, a urethane (meth) acrylate compound can be easily synthesized by heating to 60 to 100 ° C. using a tin-based compound such as dibutyltin dilaurate as a catalyst. Moreover, in order to adjust the viscosity of the urethane (meth) acrylate, a reactive diluent such as (meth) acrylate having a low viscosity that is not directly related to the reaction at the time of synthesis may be used.

  In particular, as component (A), hexamethylene diisocyanate and an isocyanurate type triisocyanate compound (isocyanurate type hexamethylene diisocyanate trimer) obtained by trimerization thereof, 2-hydroxypropyl acrylate and pentaerythritol A urethane acrylate compound obtained by reacting with triacrylate is preferred. Examples of such urethane acrylate compounds include mixtures of urethane acrylate compounds represented by the following structural formulas (1) to (7). When such a component (A) is used, the resin composition has a relatively low polymerization shrinkage rate, is hard to be colored during curing, and has excellent curability, light resistance, scratch resistance, and heat resistance of the cured product. It is also suitable for adjusting the dynamic elastic modulus of the resin composition to the optimum range.

  The molar ratio of hexamethylene diisocyanate to the isocyanurate-type hexamethylene diisocyanate trimer is preferably in the range of 2.0 to 4.0. If this molar ratio is within the above range, the shrinkage rate of the cured product will not become too large, and the dynamic elastic modulus of the cured product will not become too high.

  The molar ratio of 2-hydroxypropyl acrylate to pentaerythritol triacrylate is preferably in the range of 0.25 to 1.0. If this molar ratio is in the above range, the toughness can be sufficiently imparted without the dynamic elastic modulus of the cured product becoming too high.

  In the configuration of the urethane acrylate compound, the molar ratio of the hydroxyl group to the isocyanate group is preferably in the range of 1.0 to 1.5. If this molar ratio is 1.0 or more, unreacted isocyanate can be prevented from remaining in the resin composition, and storage stability can be improved. Moreover, if this molar ratio is 1.5 or less, unreacted pentaerythritol triacrylate and 2-hydroxypropyl acrylate can reduce content, and it can prevent that cure shrinkage becomes large.

  The blending amount of the component (A) is preferably 5 to 90 parts by weight, more preferably 10 to 80 parts by weight with respect to 100 parts by weight of the total amount of the components (A), (B) and (D). Especially preferably, it is 10-50 mass parts. The lower limits of the above ranges are significant in terms of scratch resistance and heat resistance of the concavo-convex structure portion of the optical film. Moreover, the upper limit of each said range is significant in the point which can adjust the dynamic elastic modulus of a resin cured material with (B) component or (D) component, and can make the curvature of a sheet | seat small.

(B) Di (meth) acrylate compound:
(B) component used for the resin composition of this invention is a di (meth) acrylate compound which does not have a urethane bond in a molecule | numerator and has two (meth) acryloyl groups. This component (B) is a component that causes a polymerization reaction or a crosslinking reaction by irradiation with active energy rays such as ultraviolet rays in the presence of a radical polymerizable photopolymerization initiator, and is mainly mixed with the component (A). It is a component for lowering the viscosity of the resin composition, improving the formability of the concavo-convex structure portion on the surface of the transparent base film, and adjusting the dynamic elastic modulus of the cured resin product to the design value.

  As the component (B), for example, aliphatic di (meth) acrylate having a molecular weight of 500 or more, bisphenol A or F-based di (meth) acrylate, and the like are preferable.

  Specific examples of the component (B) include di (meth) acrylates of polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, caprolactone-modified di (meth) acrylates of hydroxypivalic acid neopentyl glycol ester, and bisphenol A. Di (meth) acrylate having an addition number of ethylene oxide of 4 mol or more, di (meth) acrylate having an addition number of ethylene oxide of hydrogenated bisphenol A of 4 mol or more, di (meth) acrylate having an addition number of ethylene oxide of bisphenol F of 4 mol or more And di (meth) acrylate having an addition number of ethylene oxide of hydrogenated bisphenol F of 4 moles or more.

  Among them, di (meth) acrylate of polybutylene glycol, di (meth) acrylate having an addition number of ethylene oxide of bisphenol A of 6 mol or more, di (meth) having an addition number of ethylene oxide of hydrogenated bisphenol A of 6 mol or more Di (meth) acrylate with an addition number of acrylate and ethylene oxide of bisphenol F of 6 mol or more, di (meth) acrylate with addition number of ethylene oxide of hydrogenated bisphenol F of 6 mol or more, adjustment of the dynamic elastic modulus of the cured resin This is preferable.

  Furthermore, the compounds represented by the following general formulas (I) and (II) are more preferable in that they do not reduce the scratch resistance of the concavo-convex structure portion of the optical film.

  The above (B) component may be used individually by 1 type, or may be used in combination of 2 or more types.

  (B) The compounding quantity of a component becomes like this. Preferably it is 10-90 mass parts with respect to 100 mass parts of total amounts of (A) component, (B) component, and (D) component, More preferably, 20-90 mass parts, Especially preferably, it is 30-80 mass parts. The lower limit of each of the above ranges is to reduce the viscosity of the resin composition, to improve the formability of the concavo-convex structure portion on the surface of the transparent substrate film, and to prevent the dynamic elastic modulus of the cured resin from becoming high. This is significant in terms of adjusting and reducing the warpage of the optical film. In addition, the upper limit value of each range is significant in that the dynamic elastic modulus of the cured resin product is not too low, and sufficient heat resistance and scratch resistance can be imparted to the uneven structure portion of the optical film.

(C) Radical photopolymerization initiator:
Component (C) used in the resin composition of the present invention is a radical photopolymerization initiator. This component (C) is a compound that initiates radical polymerization of an ethylenically unsaturated compound by free radicals generated by irradiating active energy rays such as ultraviolet rays and visible rays.

As the component (C), a wide variety of compounds conventionally known as photo radical polymerization initiators can be used. Specific examples of the ultraviolet-sensitive radical photopolymerization initiator that can be used as the component (C) include benzoin, benzoin monomethyl ether, benzoin monoethyl ether, benzoin isopropyl ether, acetoin, acetophenone, benzyl, benzophenone, and p-methoxybenzophenone. , Diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, methylphenylglyoxylate, ethylphenylglyoxylate, 2 -Hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino -1- (4-morpholinophenyl) butanone-1,2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] -phenyl} -2-methylpropane-1- ON [Ciba Specialty Chemicals Co., Ltd., trade name IRGACURE127] and other carbonyl compounds; tetramethylthiuram monosulfide, tetramethylthiuram disulfide and other sulfur compounds; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis And acylphosphine oxides such as (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. Specific examples of the visible light sensitive radical photopolymerization initiator that can be used as the component (C) include camphorquinone, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium [manufactured by Ciba Specialty Chemicals Co., Ltd., trade name IRGACURE784] and the like.

  Among them, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzoin monoethyl ether, 1-hydroxycyclohexyl phenyl ketone, methylphenylglyoxylate, 2-hydroxy-2-methyl-1-phenyl Propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] -phenyl} -2-methylpropan-1-one, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) butanone-1,2,4,6-trimethylbenzoyldiphenylphosphine oxide is preferable in terms of curability and colorability of the cured resin.

  The above radical photopolymerization initiators may be used alone or in combination of two or more.

  The blending amount of the component (C) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 100 parts by mass with respect to 100 parts by mass of the total amount of the components (A), (B) and (D). 5 parts by mass, particularly preferably 0.1 to 4 parts by mass. The lower limits of the above ranges are significant in terms of curability due to the active energy rays of the resin composition. The upper limits of the above ranges are significant in that the uneven structure portion of the optical film can be prevented from being markedly yellow.

(D) Compound having one polymerizable double bond group in the molecule:
Component (D) used in the resin composition of the present invention is a compound having one polymerizable double bond group in the molecule. This component (D) is a component that causes a polymerization reaction by irradiation with active energy rays such as ultraviolet rays in the presence of a radically polymerizable photopolymerization initiator, and reduces the viscosity of the resin composition, and the surface of the transparent substrate film This is a component for improving the formability of the concavo-convex structure portion and further relaxing a part of internal stress generated in the cured resin due to polymerization shrinkage during curing. That is, the warp of the optical film can be reduced by adding the component (D) to the components (A) to (C).

  As the component (D), typically, a mono (meth) acrylate compound can be used. However, the present invention is not limited to this, and any compound having one double bond in the molecule may be used. Specific examples of the component (D) include phenyl (meth) acrylate, benzyl (meth) acrylate, phenylethyl (meth) acrylate, phenoxyethyl (meth) acrylate, paracumylphenol ethylene oxide modified (meth) acrylate, and isobornyl (meth). Acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, laur (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phosphoethyl (meth) acrylate, (meth) acryloylmorpholine, dicyclopentadiene ( And (meth) acrylate, styrene, vinyltoluene, chlorostyrene and the like.

  The above (D) component may be used individually by 1 type, or may be used in combination of 2 or more types.

  The amount of component (D) is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 100 parts by mass with respect to the total amount of component (A), component (B) and component (D). 15 parts by mass, particularly preferably 1 to 10 parts by mass. The lower limits of the above ranges are significant in that the viscosity of the resin composition is reduced and the warp of the optical film is reduced. Moreover, the upper limit of each said range is significant in the heat resistant point etc. of the uneven | corrugated structure part of an optical film.

(E) Other ingredients:
Furthermore, in the resin composition of the present invention, a fluorine-containing compound or a compound having a long-chain alkyl group having 8 or more carbon atoms may be used as necessary for improving scratch resistance or releasing property. . Specific examples of the fluorine-containing compound include trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and the like. Specific examples of the compound having a long-chain alkyl group having 8 or more carbon atoms include dimer diol (for example, product name Prepol 2033, manufactured by Unikema), and long-chain alkyl compounds such as di (meth) acrylate of dimer diol. it can.

  In addition, antioxidants, UV absorbers, light stabilizers (HALS, etc.), leveling agents, heat stabilizers, film material modifiers, flame retardants, polymerization inhibitors, radical thermal polymerization initiators, cationic light, as appropriate Various additives such as a polymerization initiator, a cationic thermal polymerization initiator, a photopolymerization accelerator, a sensitizer, a release agent, and an antistatic agent may be contained.

  The amount of component (E) used is within a range that does not affect the essential effects of the resin composition of the present invention, for example, with respect to 100 parts by mass of the total amount of component (A), component (B) and component (D). It is preferable to add 0 to 10 parts by mass, more preferably 0 to 4 parts by mass.

  The active energy ray-curable resin composition of the present invention consisting of the above components (A) to (D) and any other component (E) uses, for example, a stirrer chip or a splashing stirrer bar. , Uniformly mixed. This mixing is suitably performed under illumination such as a yellow lamp so that photopolymerization does not start.

  The transparent substrate film 14 is not particularly limited as long as it transmits an active energy ray. For example, a film made of a resin or glass such as an acrylic resin, a polycarbonate resin, a polyester resin, a vinyl chloride resin, or a polymethacrylimide resin. Sheets or plates can be used. The thickness of the transparent base film 14 is, for example, 25 to 250 μm.

  The uneven structure portion 12 may be provided directly on the surface of the transparent base film 14. Further, in order to improve the adhesion to the transparent substrate film 14, the surface of the transparent substrate film 14 is subjected to a surface treatment for improving adhesion to form a surface treatment layer, and then the concavo-convex structure portion 12 is provided. May be. As this surface treatment, for example, a method of forming an easy-adhesion layer made of polyester resin, acrylic resin, urethane resin or the like on the surface of the transparent substrate film 14, or the surface of the transparent substrate film 14 is roughened. The method is mentioned. Further, on the side of the transparent base film 14 opposite to the concavo-convex structure portion 12, the light is extracted in order to further improve the light extraction efficiency, or to reduce the wavelength dependency due to the outgoing angle of the transmitted light and make it more uniform. A diffusion layer may be provided. This light diffusion layer can be formed by, for example, blending active energy ray-curable resin with a diffusing agent such as organic fine particles or silica fine particles having different refractive indexes.

  The transparent substrate film 14 can be subjected to other treatments such as antistatic, antireflection, and adhesion prevention between substrates.

  In FIG. 7, the manufacturing apparatus of the optical film 1 is shown. With reference to FIG. 7, it demonstrates below about the manufacturing method of the optical film 1. FIG.

  A cylindrical mold 7 having a transfer surface for transferring and forming a surface on which the uneven unit shape 12a of the uneven structure portion 12 of the optical film 1 is transferred, and a rubber nip roll 6 In the meantime, the transparent sheet-like substrate 5 (that is, the transparent substrate film 14) is introduced. In a state where the transparent sheet-like base material 5 is introduced, the active energy ray-curable resin composition 10 is passed from the tank 8 through the pipe 9 having a nozzle attached to the tip thereof, and between the cylindrical mold 7 and the transparent sheet-like base material. The transparent sheet-like base material 5 is moved while being supplied. At this time, the cylindrical mold 7 is rotated in accordance with this, and the active energy ray-curable resin composition 10 sandwiched between the cylindrical mold 7 and the transparent sheet-like substrate 5 is a high-pressure mercury lamp. When it comes to the vicinity of the ultraviolet irradiation device 11 using a light source or the like as a light source, it is cured by ultraviolet irradiation. After passing through the lamp, it is released from the cylindrical mold 7 to obtain an optical film 12 '(that is, the optical film 1).

  In addition, inside or outside of the tank 8 and the cylindrical mold 7 for storing the active energy ray-curable resin composition, heat source equipment such as a sheathed heater and a hot water jacket is arranged to keep the temperature constant. The resin temperature in the tank 8 and the surface temperature of the cylindrical mold 7 are appropriately maintained.

  Examples of the mold (mold member) used for manufacturing the optical film 1 include metal molds such as aluminum, brass, and steel, silicon resin, urethane resin, epoxy resin, ABS resin, fluororesin, polymethylpentene resin, and the like. And a mold made from a material obtained by plating these materials or a mixture of various metal powders. In particular, a metal mold is preferable in terms of heat resistance and strength, and is suitable for continuous production. More specifically, the metal mold has advantages such as being resistant to polymerization heat generation, difficult to deform, hardly scratched, temperature controllable, and suitable for precision molding.

  In these molds, as a method of creating a transfer surface for transferring and forming the surface of the concavo-convex structure portion 12 of the optical film 1 on which the concavo-convex unit shape 12a is formed, cutting with a diamond bite or WO2008 / 069324 Etching as described in. The former is suitable when the unit shape 12a is a combination of substantially planes such as a pyramid shape, a truncated pyramid shape, a cone shape, a truncated cone shape, and a roof shape, and the latter is suitable for the unit shape 12a being a hemispherical shape. Or it is suitable in the case of what has curved surfaces, such as a hemispherical trapezoid shape. In addition, a method of producing a cylindrical mold by winding a metal thin film produced by electroforming from a master die having a transfer surface having a shape in which the unevenness of the transfer surface shape is reversed is used. be able to. Further, the transfer surface can be roughened to such an extent that the unit structure is not lost completely by blasting, and the dependency of the light emitted from the optical device on the output angle can be reduced by the light diffusion effect of the rough surface.

As the active energy ray light source, for example, a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an electrodeless UV lamp (manufactured by Fusion UV Systems), a visible light halogen lamp, a xenon lamp, sunlight, etc. can be used. . The atmosphere at the time of irradiation with active energy rays may be air or an inert gas such as nitrogen or argon. As the irradiation energy, for example, the integrated energy in the wavelength range of 200 to 600 nm, preferably 320 to 390 nm is, for example, 0.01 to 10 J / cm ² , preferably 0.5 to 8 J / cm ^2. It is appropriate to irradiate.

  Hereinafter, the present invention will be described with reference to examples and comparative examples.

  In the following examples and comparative examples, “part” means part by mass unless otherwise specified.

  Evaluation methods in the following examples and comparative examples were as follows.

  Electron microscope observation (SEM): Measured using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, S-4300-SE / N).

  Laser microscope observation: Measured using a 3D measurement laser microscope (manufactured by Olympus, LEXT OLS4000).

Normal brightness:
The optical film on the surface of a commercially available organic EL device (LUMIOTEC, design sample kit, light emitting part size: 125 mm × 125 mm) was peeled off to expose the glass surface, and used as a light source for evaluation. Next, using a 25μm-thick substrate-less double-sided adhesive tape (LUCIACS CS9621T, manufactured by Nitto Denko Corporation), attach the optical film to be measured to the glass surface of the light source for evaluation so that the surface on the concavo-convex structure side faces the light output side. It was. In this state, the evaluation light source was turned on by passing a current of 1.5 A, and the normal luminance was measured using a luminance meter (Topcon, BM-7).

Outgoing light flux:
As with normal luminance measurement, the light source with the optical film attached is turned on under the same conditions as with normal luminance measurement, and the light emitting part with the optical film attached is an integrating sphere with a 25 mm diameter opening. The light emitted from the surface of the light source was incident on an integrating sphere. The total amount of incident radiant flux was measured with a multi-channel spectroscope (manufactured by Hamamatsu Photonics Co., Ltd., PMA-11) connected to an integrating sphere, and the amount of emitted light flux was calculated by correcting with the standard visibility curve.

Scratch resistance:
The light source with the optical film attached was evaluated using a friction fastness tester (RT-200, manufactured by Daiei Kagaku Seisakusho Co., Ltd.) in the same manner as in the normal luminance measurement. As the friction element, a 5-mm square PET film with a size of 188 μm is attached to the center of a planar friction element (20 mm x 20 mm), and an anti-glare film is attached on top of it. It carried out in. Evaluation was made according to the following criteria visually when the light source was not lit:
○ No scratches can be confirmed after 1 day after friction;
X Scratches remain visible even after 1 day after friction.

[Production Example] Production of active energy ray-curable resin composition resin:
In a glass flask, 117.6 g (0.7 mol) of hexamethylene diisocyanate and 151.2 g (0.3 mol) of isocyanurate-type hexamethylene diisocyanate trimer as isocyanate compounds, and (meth) acryloyl having a hydroxyl group As compounds, 128.7 g (0.99 mol) of 2-hydroxypropyl acrylate and 693 g (1.54 mol) of pentaerythritol triacrylate, 100 ppm of dilaurate di-n-butyltin as a catalyst, and polymerization inhibitor, Hydroquinone monomethyl ether (0.55 g) was charged and reacted under the conditions of 70 to 80 ° C. until the residual isocyanate concentration became 0.1% or less to obtain a urethane acrylate compound. This urethane acrylate compound is a mixture of urethane acrylate compounds represented by the structural formulas (1) to (7) described above.

  As the component (A), 35 parts of the urethane acrylate compound, and as the component (B), dimethacrylate represented by the following formula (9) [compound of general formula (I) where 9 is 9] (trade name acrylate ester) 25 parts of PBOM (manufactured by Mitsubishi Rayon Co., Ltd.) and 40 parts of dimethacrylate (trade name New Frontier BPEM-10, Daiichi Kogyo Seiyaku Co., Ltd.) represented by the following formula (10), (C) As an ingredient, 1.2 parts of 1-hydroxycyclohexyl phenyl ketone (trade name Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was mixed to obtain an active energy ray-curable resin composition.

[Reference example]
When the normal luminance and the amount of emitted light flux of the light source for evaluation (that is, the state where no optical film is present on the surface) were measured, the normal luminance was 3570 [cd / m 2] and the amount of emitted light flux was 62.8 × 10 ^{−. 3} [lm].

[Example 1]
A die member was prepared by cutting a die member having an electroless nickel plating layer of 500 μm formed on a 10 mm-thick stainless alloy as a base material of the die member using a diamond bit having an isosceles triangle shape with an apex angle of 100 °. The obtained mold member has a shape in which convex portions in which square pyramids are deformed into a tent shape are arranged. The active energy ray-curable resin composition prepared in Production Example 1 is uniformly applied to this mold member, and a PET film with a thickness of 188 μm (Toyobo Co., Ltd., Cosmo Shine A4300) is placed on the mold member and stretched uniformly with a hand roll. It was. Thereafter, UV irradiation was performed on the PET film, and the active energy ray-curable resin composition stretched between the mold member and the PET film was cured. The PET film was peeled off from the mold member, and an optical film A having a shape in which the convex shape of the mold member was inverted on the surface of the PET film was obtained. An SEM observation image of the surface is shown in FIG. As shown in the SEM image, concave tent shapes (uneven unit shapes) having a long side of 66 μm, a short side of 33 μm, a depth of about 14 μm, and a base angle of 40 degrees were regularly arranged without gaps.

  The obtained optical film A was evaluated for normal luminance, emitted light flux, and scratch resistance, and Table 1 shows the results. In Table 1, “uneven pattern forming resin” refers to a resin that forms an uneven structure having an uneven unit shape.

  When the case where there was no optical film was taken as 100%, it was confirmed that the normal luminance was 160%, the luminance in the normal direction was improved, and the emitted light flux was 132%, which improved the light extraction efficiency. Further, the scratches generated in the scratch resistance test were restored to the original scratch-free state within one day.

[Comparative Example 1]
Using the mold member of Example 1, a cycloolefin polymer (Zeonor, manufactured by Nippon Zeon Co., Ltd.) as a molding resin is press-molded under the condition of a mold temperature of 250 degrees, and a concave tent shape is formed on the surface as in Example 1. An optical film B having a shape and a thickness of 300 μm was obtained. The obtained optical film B was evaluated for normal luminance, emitted light flux, and scratch resistance, and the results are shown in Table 1. Unlike the example 1, the surface of the organic EL element after the scratch resistance test was visually recognized after the lapse of one day without restoring the scratches.

[Example 2]
Using the same mold member as in Example 1, a mold member was produced using a diamond bit having a right isosceles triangle shape with an apex angle of 90 degrees. The obtained mold member has a shape in which convex portions of triangular pyramids are arranged. An optical film C was obtained in the same manner as in Example 1 except that this mold member was used. An SEM observation image of the surface is shown in FIG. As shown in the SEM image, a concave triangular pyramid shape (uneven unit shape) having a regular bottom of 42 μm on a side, a depth of about 12 μm, and a base angle of 45 degrees was regularly arranged. Table 1 shows the results of evaluating the obtained optical film C in the same manner as in Example 1.

[Example 3]
A microlens-shaped mold member was produced by the etching method described in WO2008 / 069324. The obtained mold member has a shape in which hemispherical concave portions are arranged. An optical film D was obtained in the same manner as in Example 1 except that this mold member was used. FIG. 4 shows a laser microscope observation image of the surface. As shown in the laser microscope image, the surface of the optical film D had regularly arranged hemispherical convex portions (uneven unit shape) having a diameter of 50 μm. The results of evaluating the obtained optical film D in the same manner as in Example 1 are shown in Table 1.

[Example 4]
Using a mold member similar to that in Example 1, a diamond mold member having an isosceles triangular shape with an apex angle of 100 degrees and further inverted by electroforming was produced. The obtained mold member has a shape in which quadrangular pyramid-shaped concave portions are arranged. An optical film E was obtained in the same manner as in Example 1 except that this mold member was used. A laser microscope observation image of the surface is shown in FIG. As shown in the laser microscope image, the surface of the optical film E was regularly arranged with quadrangular pyramid-shaped projections (unevenness unit shape). The bottom surface of this quadrangular pyramid was a square with a side of 50 μm, and the difference in height between the bottom surface and the top surface was 10 μm. Table 1 shows the results of evaluating the obtained optical film E in the same manner as in Example 1.

[Example 5]
Using a mold member similar to that of Example 1, a diamond mold member having an isosceles triangular shape with an apex angle of 60 degrees and further inverted by electroforming was produced. The obtained mold member has a shape in which quadrangular pyramid-shaped concave portions are arranged. An optical film F was obtained in the same manner as in Example 1 except that this mold member was used. FIG. 6 shows a laser microscope observation image of the surface. As shown in the laser microscope image, the surface of the optical film F had regularly arranged pyramid-shaped convex portions (uneven unit shape). The bottom surface of this quadrangular pyramid was a square with a side of 50 μm, and the difference in height between the bottom surface and the top surface was 30 μm. Table 1 shows the results of evaluating the obtained optical film F in the same manner as in Example 1.

DESCRIPTION OF SYMBOLS 1 Optical film 12 Uneven structure part 12a Uneven unit shape 14 Transparent base film 2 Optical device 22 Transparent base material layer 24 Transparent electrode layer 26 Organic light emitting layer 28 Metal electrode layer 5 Transparent sheet-like base material 6 Rubber nip roll 7 Cylindrical gold Mold 8 Tank 9 Piping 10 Active energy ray curable resin composition 11 Ultraviolet irradiation device 12 'Optical film

Claims (4)

An optical film having an uneven structure part,
The concavo-convex structure portion includes the following components (A), (B) and (C):
(A) a urethane (meth) acrylate compound containing at least one urethane (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule;
(B) a di (meth) acrylate compound having no urethane bond in the molecule and having two (meth) acryloyl groups,
(C) a radical photopolymerization initiator,
An active energy ray-curable resin containing
The concavo-convex structure portion has a concavo-convex structure formed on one surface,
The surface on the concave-convex structure side of the concave-convex structure portion has a shape formed by repeatedly arranging concave-convex unit shapes in at least one direction along the surface on the concave-convex structure side.   The concavo-convex unit shape is generally a pyramid shape, a truncated pyramid shape, a cone shape, a truncated cone shape, a roof shape, a hemispherical shape or a hemispherical trapezoid shape, and has a protrusion or a depression. 1. The optical film as described in 1.   3. The optical film according to claim 1, wherein the optical film further comprises a transparent substrate film bonded to a surface opposite to the surface of the concavo-convex structure portion on the concavo-convex structure side. An optical film according to any one of claims 1 to 3, and an optical device bonded to the surface of the optical film, located on the opposite side of the surface of the concavo-convex structure portion to the concavo-convex structure side. And
An optical apparatus, wherein light emitted from the optical device is emitted from a surface of the concavo-convex structure portion of the optical film on the concavo-convex structure side.