JP2016018050A - Optical film, surface light emitter, and manufacturing method for optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film which improves light extraction efficiency and frontal luminance of a surface light emitter and suppresses exit angle dependence of an output light wavelength of the surface light emitter.SOLUTION: An optical film includes a plurality of convex microlenses 11, each comprising a portion α 12 and a portion β 13. The portion β occupies an outer portion of the convex shape and is positioned to cover the portion α that contains a matrix resin Mand light diffusion fine particles P. Difference in refractive index between the matrix resin Mconstituting the portion α and the light diffusion fine particles Pincluded in the portion α shall be no less than 0.12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical film, a surface light emitter, and a method for producing an optical film.

  Among surface light emitters, organic EL (electroluminescence) elements are expected to be used in next-generation lighting and flat panel displays that can replace fluorescent lamps and the like.

  The structure of the organic EL element is diversified from a simple structure in which an organic layer serving as a light emitting layer is sandwiched between two electrodes to a multilayered structure. Examples of the latter multilayered structure include a structure in which a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are laminated on an anode provided on a glass substrate. The layer sandwiched between the anode and the cathode is mainly composed of an organic layer, and the thickness of each organic layer is as thin as several tens of nm.

The organic EL element is a laminated body of thin layers, and the total reflection angle of light between the thin layers is determined by the difference in refractive index between the materials of the thin layers. At present, about 80% of the light generated in the light emitting layer is confined inside the organic EL element and cannot be extracted outside. Specifically, when the refractive index of the glass substrate is 1.5 and the refractive index of the air layer is 1.0, the critical angle θ _c is 41.8 °, and the incident angle is smaller than the critical angle θ _c. the light is emitted from the glass substrate to the air layer, the light of the larger incident angle than the critical angle theta _c is confined within the glass substrate by total internal reflection. Therefore, it is required to extract light confined inside the glass substrate on the surface of the organic EL element to the outside of the glass substrate, that is, to improve light extraction efficiency and front luminance.

  Further, regarding an organic EL element that emits isotropically, it is required that the light extraction efficiency and the front luminance are improved and that the emission angle dependency of the wavelength of light emitted from the organic EL element is small. That is, when the light emitted from the light emitting layer passes through the glass substrate and is emitted from the glass substrate, the difference in the emission angle depending on the wavelength is small, in other words, the distribution of the light emitted from the glass substrate has wavelength dependency. There is a demand for as little as possible.

  For example, Patent Document 1 proposes an optical film having two layers of microlenses.

International Publication No. 2013/080794 Pamphlet

  Although the optical film proposed in Patent Document 1 is excellent in scratch resistance, the difference in refractive index between the matrix resin and the light diffusing fine particles is small, and the front luminance of the surface light emitter is not sufficient.

  Accordingly, an object of the present invention is to provide an optical film that improves the light extraction efficiency and front luminance of a surface light emitter, and suppresses the emission angle dependence of the emitted light wavelength of the surface light emitter.

In the present invention, a plurality of convex microlenses are arranged, the microlens has a region α and a region β, and the region β occupies the convex outer portion of the microlens and is positioned so as to cover the region α. The region α includes the matrix resin M _α and the light diffusing fine particles P _α , and the refractive index of the matrix resin M _α constituting the region α and the light diffusing fine particles P _α included in the region _α . The present invention relates to an optical film having a difference from the refractive index of 0.12 or more.

Moreover, this invention relates to the surface light-emitting body containing the said optical film and EL element.
Furthermore, this invention relates to the manufacturing method of the said optical film including following process AD performed sequentially.
Step A: Rotate a roll mold having an outer peripheral surface on which a plurality of concave microlens transfer portions are arranged, and run the substrate along the outer periphery of the roll mold in the rotation direction of the roll mold while rotating the outer periphery of the roll mold Step of applying active energy ray-curable composition β to the surface and filling a part of the microlens transfer portion with active energy ray-curable composition β Step B: Active between the outer peripheral surface of the roll mold and the substrate Step of supplying energy ray curable composition α Step C: In the state where active energy ray curable composition α is sandwiched at least between the outer peripheral surface of the roll mold and the substrate, the outer peripheral surface of the roll mold and the substrate Step of irradiating and curing the active energy ray to the region between the steps Step D: Step of peeling the cured product obtained in Step C from the roll mold

The optical film of the present invention improves the light extraction efficiency and front luminance of the surface light emitter, and suppresses the emission angle dependence of the emitted light wavelength of the surface light emitter.
The surface light emitter of the present invention is excellent in light extraction efficiency and front luminance, and suppresses the output angle dependency of the output light wavelength.
The method for producing an optical film of the present invention is excellent in productivity of the optical film of the present invention.

It is a schematic diagram which shows an example of the convex-shaped microlens of the optical film of this invention. It is the schematic diagram which looked at the example of arrangement | positioning of the micro lens of the optical film of this invention from the upper direction of the optical film. It is the schematic diagram which looked at an example of the optical film of this invention from the upper direction of the optical film. It is a schematic diagram which shows an example of the cross section of the optical film of this invention. It is a schematic diagram which shows an example of the apparatus used for the manufacturing method of the optical film of this invention. It is a schematic diagram which shows an example of the cross section of the surface light-emitting body of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these drawings.

  In the optical film of the present invention, a plurality of convex microlenses are arranged, the microlens has a region α and a region β, the region β occupies the convex outer portion of the microlens, and covers the region α. Is located.

(Micro lens)
An example of a convex microlens is shown in FIG. FIG. 1A is a schematic cross-sectional view, and FIG. 1B is a schematic perspective view.
The microlens 11 shown in FIG. 1 has an area α indicated by reference numeral 12 and an area β indicated by reference numeral 13, and the area β indicated by reference numeral 13 occupies the convex outer portion of the microlens 11. 12 is located so as to cover an area α indicated by 12. Reference numeral 16 denotes a bottom surface portion of the microlens.

  The region β may completely cover the region α or may be covered so that a part thereof is exposed to the outside. However, since the region β sufficiently plays the role of the region β in the optical film, the region β is as much as possible in the region β. It is preferable to cover.

The shape of the microlens is, for example, a spherical shape, a spherically truncated shape, an elliptical spherical shape (a shape obtained by cutting a spheroid on one plane), or an elliptical spherical shape (a spheroid is parallel to each other). Shape cut by two planes), pyramid shape, truncated pyramid shape, cone shape, truncated cone shape, roof shape related to these (spherical shape, spherical truncated shape, elliptical spherical shape, elliptical sphere) A truncated shape, a pyramid shape, a truncated pyramid shape, a cone shape, or a shape in which the truncated cone shape extends along the bottom surface portion). These microlenses may be used singly or in combination of two or more. Among these microlens shapes, since the light extraction efficiency and front luminance of the surface light emitter are excellent, a spherical notch shape, a spherically truncated trapezoidal shape, an elliptical spherically truncated shape, an elliptical spherically truncated shape, a pyramid shape, a pyramid shape A trapezoidal shape is preferable, a spherically-notched shape, an elliptical spherically-notched shape, and a pyramidal shape are more preferable, and a spherically-notched shape and an elliptical spherically-notched shape are more preferable.
Each shape in this specification does not need to be exactly that shape, and includes shapes that are very similar.

An arrangement example of the microlens is shown in FIG.
As the arrangement of the microlenses, for example, a hexagonal array (FIG. 2A), a rectangular array (FIG. 2B), a rhombus array (FIG. 2C), a linear array (FIG. 2D), A circular arrangement (FIG. 2 (e)), a random arrangement (FIG. 2 (f)) and the like can be mentioned. Among these microlens arrangements, a hexagonal arrangement, a rectangular arrangement, and a rhombus arrangement are preferable, and a hexagonal arrangement and a rectangular arrangement are more preferable because of excellent light extraction efficiency and front luminance of the surface light emitter.

The bottom surface portion of the microlens refers to a virtual planar portion surrounded by the outer peripheral edge of the bottom portion of the microlens (if the base layer described later is in contact with the base layer).
The longest diameter L of the bottom surface portion of the microlens is the length of the longest portion of the bottom surface portion of the microlens, and the average longest diameter _Lave of the bottom surface portion of the microlens is the surface of the optical film having the microlens. The images are taken with a microscope, and the longest diameter L of the bottom surface of the microlens is measured at five arbitrary points, and the average value is obtained.

The height H of the micro lens, refers to the highest to the site height of the microlens from the bottom portion of the microlens, the average height H _ave microlenses a cross section of an optical film was photographed with an electron microscope, The height H of the microlens is measured at five arbitrary points, and the average value is obtained.
The height h of the region α refers to the height from the bottom surface portion of the microlens to the highest portion of the region α, and the average height h _ave of the region α is obtained by photographing a cross section of the optical film with an electron microscope, The height h of the region α is measured at any five points, and the average value is obtained.

The average longest diameter L _ave of the bottom surface portion of the microlens is preferably 2 μm to 200 μm, more preferably 6 μm to 150 μm, and even more preferably 10 μm to 100 μm, because the light extraction efficiency and front luminance of the surface light emitter are excellent.

The average height H _ave of the microlens is preferably 1 μm to 100 μm, more preferably 3 μm to 75 μm, and even more preferably 5 μm to 50 μm, because of the excellent light extraction efficiency and front luminance of the surface light emitter.

The aspect ratio of the microlens is preferably 0.3 to 1.4, more preferably 0.35 to 1.3, and more preferably 0.4 to 1.0 because the light extraction efficiency and front luminance of the surface light emitter are excellent. Is more preferable.
The aspect ratio of the micro lens is a value calculated from the average height H _{ave of the} micro lens / the average longest diameter L _ave of the bottom surface of the micro lens.

  Examples of the shape of the bottom surface of the microlens include a polygon such as a triangle and a quadrangle; a circle such as a perfect circle and an ellipse; an indefinite shape, and the like. The shape of the bottom part of these microlenses may be used alone or in combination of two or more. Among the shapes of the bottom surfaces of these microlenses, a polygonal shape and a circular shape are preferable, and a circular shape is more preferable because of excellent light extraction efficiency and front luminance of the surface light emitter.

An example of the optical film viewed from above is shown in FIG.
The ratio of the area of the bottom surface of the microlens (area surrounded by a dotted line in FIG. 3) to the area of the optical film (area surrounded by a solid line in FIG. 3) is the light extraction efficiency and front luminance of the surface light emitter. 20% to 100% is preferable, 25% to 97% is more preferable, and 30% to 94% is still more preferable.

The average height h _ave of the region α is preferably 0.5 μm to 80 μm, more preferably 1.5 μm to 60 μm, and even more preferably 2.5 μm to 30 μm, because the light extraction efficiency and front luminance of the surface light emitter are excellent. .

Since the ratio of the average height h _ave of the region α to the average height H _ave of the microlens (h _ave / H _ave ) is excellent in the light extraction efficiency and the front luminance of the surface light emitter, it is 0.05 to 0.96. Is preferable, 0.1 to 0.92 is more preferable, and 0.2 to 0.88 is still more preferable.

The average volume ratio of the region α is preferably 1% by volume to 90% by volume and more preferably 2% by volume to 80% by volume since the role of the region α in the optical film is sufficiently fulfilled in 100% by volume of the microlens. A volume% to 70 volume% is more preferable.
The average volume ratio of the region α is synonymous with the volume ratio of the cured product of the active energy ray-curable composition α described later in the microlens.
The average volume ratio of the region β is preferably 10% by volume to 99% by volume, more preferably 20% by volume to 98% by volume since the role of the region β in the optical film is sufficiently fulfilled in 100% by volume of the microlens. A volume% to 97 volume% is more preferable.
The average volume ratio of area | region (beta) is synonymous with the volume ratio of the hardened | cured material of the active energy ray-curable composition (beta) mentioned later in a microlens.

In the microlens, another region may exist between the region α and the region β. The other region may be a single layer or a plurality of layers.
Examples of the other region include an intermediate region having a refractive index between the refractive index of the matrix resin M _α constituting the region α and the refractive index of the matrix resin M _β constituting the region β. By providing such an intermediate region, the Fresnel reflection loss is further reduced, so that a surface light emitter that is more excellent in light extraction efficiency can be obtained.

(Region α)
The region α includes a matrix resin M _α and light diffusion particles P _α .

The matrix resin M _α constituting the region α is not particularly limited as long as it has a high light transmittance in the visible light wavelength region (approximately 400 nm to 700 nm). For example, acrylic resin; polycarbonate resin; polyethylene terephthalate, polybutylene terephthalate And polyester resins such as polyethylene naphthalate; styrene resins such as polystyrene and ABS resin; and vinyl chloride resins. These matrix resins _Mα may be used alone or in combination of two or more. Among these matrix resins M _alpha, high transmittance in the visible light wavelength range, heat resistance, mechanical properties, since it is excellent in molding processability, acrylic resins are preferred.

Light transmittance of the matrix resin M _alpha is excellent in appearance of the optical film, due to excellent light extraction efficiency and front brightness of the surface light emitters, preferably 50% to 95%, more preferably 60% to 90%.
The light transmittance of each resin in the present specification is a value measured according to ISO 13468.

Refractive index of the matrix resin M _alpha is excellent in light extraction efficiency and front brightness of the surface light emitters, preferably 1.30 to 2.00, more preferably 1.35 to 1.90, 1.40 to 1 .80 is more preferred.
The refractive index of each material in this specification shall be the value measured using the sodium D line | wire at 20 degreeC.
When the matrix resin _Mα is a resin in which two or more kinds of resins are mixed, the refractive index of the matrix resin _{Mα is} the refractive index of the mixed resin.

Since the matrix resin _Mα is excellent in productivity of the optical film, a resin obtained by irradiating the active energy ray-curable composition with active energy rays and curing it is preferable.
Examples of the active energy ray include ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable because the active energy ray-curable composition is excellent in curability and can suppress deterioration of the optical film.

  The active energy ray-curable composition is not particularly limited as long as it can be cured by active energy rays, but the active energy ray-curable composition is excellent in handleability and curability, and the flexibility, heat resistance, scratch resistance, An active energy ray-curable composition containing a non-crosslinkable monomer (A), a crosslinkable monomer (B) and a polymerization initiator (C) because it has excellent physical properties such as solvent resistance and light transmittance. Is preferred.

Examples of the non-crosslinkable monomer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, alkyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylic , Isobornyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) Acrylate, tetracyclododecanyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy Butyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-eth Siethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, 2- (meth) acryloyloxymethyl-2 -Methylbicycloheptane, 4- (meth) acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane , (Meth) acrylates such as trimethylolpropane formal (meth) acrylate, ethylene oxide modified phosphoric acid (meth) acrylate and caprolactone modified phosphoric acid (meth) acrylate; (meth) acrylic acid; (meth) acrylonitrile (Meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-butyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxy (Meth) acrylamides such as methyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, (meth) acryloylmorpholine, hydroxyethyl (meth) acrylamide, and methylenebis (meth) acrylamide; bisphenols (bisphenol A, bisphenol F, (Meth) acrylic acid or a derivative thereof is reacted with a bisphenol type epoxy resin obtained by condensation reaction of bisphenol S, tetrabromobisphenol A, etc.) and epichlorohydrin Epoxy (meth) acrylates; aromatic vinyls such as styrene and α-methylstyrene; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and 2-hydroxyethyl vinyl ether; vinyl carboxylates such as vinyl acetate and vinyl butyrate Olefins such as ethylene, propylene, butene and isobutene; These non-crosslinkable monomers (A) may be used individually by 1 type, and may use 2 or more types together. Among these non-crosslinkable monomers (A), the active energy ray-curable composition is excellent in handleability and curability, and the flexibility, heat resistance, scratch resistance, solvent resistance, and light transmittance of the optical film. (Meth) acrylates, epoxy (meth) acrylates, and olefins are preferable, and (meth) acrylates and epoxy (meth) acrylates are more preferable.
(Meth) acrylate refers to acrylate or methacrylate.

  The content of the non-crosslinkable monomer (A) is preferably 0.5% by mass to 60% by mass and more preferably 1% by mass to 57% by mass in 100% by mass of the active energy ray-curable composition. A mass% to 55 mass% is more preferable. When the content of the non-crosslinkable monomer (A) is 0.5% by mass or more, the handleability of the active energy ray-curable composition is excellent and the adhesiveness of the optical film to the substrate is excellent. Moreover, it is excellent in the crosslinkability and sclerosis | hardenability of an active energy ray curable composition as the content rate of a non-crosslinkable monomer (A) is 60 mass% or less, and it is excellent in the solvent resistance of an optical film.

  Examples of the crosslinkable monomer (B) include hexa (meth) acrylates such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate; dipentaerythritol hydroxypenta (meth) acrylate , Penta (meth) acrylates such as caprolactone-modified dipentaerythritol hydroxypenta (meth) acrylate; ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxy modified tetra (meth) acrylate, dipenta Tests such as erythrole hexa (meth) acrylate, dipentaerystol penta (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, etc. La (meth) acrylates; trimethylolpropane tri (meth) acrylate, trisethoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, tris ( Tri (meth) acrylates such as 2- (meth) acryloyloxyethyl) isocyanurate, C2-C5 aliphatic hydrocarbon modified trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate Triethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) Acrylate, 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, methylpentanediol di (meth) Acrylate, diethylpentanediol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, Tricyclodecane dimethanol di (meth) acrylate, 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxyethoxy) Enyl) propane, 2,2-bis (4- (3- (meth) acryloxy-2-hydroxypropoxy) phenyl) propane, 1,2-bis (3- (meth) acryloxy-2-hydroxypropoxy) ethane, 1 , 4-bis (3- (meth) acryloxy-2-hydroxypropoxy) butane, bis (2- (meth) acryloyloxyethyl) -2-hydroxyethyl isocyanurate, cyclohexanedimethanol di (meth) acrylate, dimethyloltri Cyclodecane di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, polyethoxylated cyclohexanedimethanol di (meth) acrylate, polypropoxylated cyclohexanedimethanol di (meth) acrylate, polyethoxy Rated bisphenol A di (meth) acrylate, polypropoxylated bisphenol A di (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, polyethoxylated hydrogenated bisphenol A di (meth) acrylate, polypropoxylated Di (meth) of hydrogenated bisphenol A di (meth) acrylate, bisphenoxyfluoreneethanol di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, and ε-caprolactone adduct of hydroxypivalate neopentyl glycol Di (meth) acrylate of γ-butyrolactone adduct of acrylate, neopentyl glycol hydroxypivalate, di (meth) of caprolactone adduct of neopentyl glycol Di (meth) acrylate of caprolactone adduct of chlorate, butylene glycol, di (meth) acrylate of caprolactone adduct of cyclohexanedimethanol, di (meth) acrylate of caprolactone adduct of dicyclopentanediol, ethylene oxide addition of bisphenol A Di (meth) acrylate of a product, di (meth) acrylate of a propylene oxide adduct of bisphenol A, di (meth) acrylate of a caprolactone adduct of bisphenol A, di (meth) acrylate of a caprolactone adduct of hydrogenated bisphenol A, Di (meth) acrylates such as di (meth) acrylates of caprolactone adducts of bisphenol F, isocyanuric acid ethylene oxide-modified di (meth) acrylates; , Diallyl such as diallyl terephthalate, diallyl isophthalate, diethylene glycol diallyl carbonate; allyl (meth) acrylate; divinylbenzene; methylenebisacrylamide; polybasic acid (phthalic acid, succinic acid, hexahydrophthalic acid, tetrahydrophthalic acid, terephthalic acid , Azelaic acid, adipic acid and the like) and polyhydric alcohols (ethylene glycol, hexanediol, polyethylene glycol, polytetramethylene glycol, etc.) and (meth) acrylic acid or a compound obtained by reaction with a derivative thereof ( (Meth) acrylates; diisocyanate compounds (tolylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, dicyclohexylmethane diisocyanate, hexamethyl) Range isocyanates) and hydroxyl-containing (meth) acrylates (2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate) A diisocyanate compound was added to the hydroxyl group of a compound obtained by reacting with a functional (meth) acrylate or the like, or an alcohol (one kind or two or more kinds such as an alkanediol, a polyether diol, a polyester diol, and a spiroglycol compound) and remained. Urethane polyfunctional (meth) acrylates such as compounds obtained by reacting an isocyanate group with a hydroxyl group-containing (meth) acrylate; divinyl ethers such as diethylene glycol divinyl ether and triethylene glycol divinyl ether; Tajien, isoprene, dienes such as dimethyl butadiene and the like. These crosslinkable monomers (B) may be used individually by 1 type, and may use 2 or more types together. Among these crosslinkable monomers (B), the optical film has excellent physical properties such as flexibility, heat resistance, scratch resistance, solvent resistance, and light transmittance. (Meth) acrylates, tetra (meth) acrylates, tri (meth) acrylates, di (meth) acrylates, diallyls, allyl (meth) acrylates, polyester di (meth) acrylates, urethane polyfunctional (meth) Acrylates are preferred, hexa (meth) acrylates, penta (meth) acrylates, tetra (meth) acrylates, tri (meth) acrylates, di (meth) acrylates, polyester di (meth) acrylates and many urethanes Functional (meth) acrylates are more preferred.

  30 mass%-98 mass% are preferable in 100 mass% of active energy ray-curable compositions, and, as for the content rate of a crosslinkable monomer (B), 35 mass%-97 mass% are more preferable, and 40 mass%- 96 mass% is still more preferable. When the content of the crosslinkable monomer (B) is 30% by mass or more, the crosslinkability and curability of the active energy ray-curable composition are excellent, and the solvent resistance of the optical film is excellent. Moreover, the softness | flexibility of an optical film is excellent in the content rate of a crosslinkable monomer (B) being 98 mass% or less.

  Examples of the polymerization initiator (C) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, benzyldimethyl ketal, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2- Carbonyl compounds such as methyl-1-phenylpropan-1-one and 2-ethylanthraquinone; tetramethylthiuram monosulfide, tetramethylthiuram disulfide and the like Huang compounds; 2,4,6-trimethylbenzoyl diphenylphosphine oxide, acylphosphine oxide such as benzo dichloride ethoxy phosphine oxide, and the like. These polymerization initiators (C) may be used individually by 1 type, and may use 2 or more types together. Among these polymerization initiators (C), carbonyl compounds and acyl phosphine oxides are preferable because the handleability and curability of the active energy ray-curable composition and the light transmittance of the optical film are preferable. More preferred.

  The content of the polymerization initiator (C) in the active energy ray-curable composition is preferably 0.1% by mass to 10% by mass, and preferably 0.5% by mass to 100% by mass in the active energy ray-curable composition. 8 mass% is more preferable, and 1 mass%-5 mass% is still more preferable. When the content of the polymerization initiator (C) is 0.1% by mass or more, the handleability and curability of the active energy ray-curable composition are excellent. Moreover, it is excellent in the light transmittance of an optical film as the content rate of a polymerization initiator (C) is 10 mass% or less.

The light diffusing fine particles P _α contained in the region α are not particularly limited as long as they have a light diffusing effect in the visible light wavelength region (approximately 400 nm to 700 nm), and known fine particles can be used. The light diffusing fine particles _Pα may be used alone or in combination of two or more.

As the material of the light diffusing fine particles P _alpha, for example, gold, silver, silicon, aluminum, magnesium, zirconium, titanium, zinc, germanium, indium, tin, antimony, a metal of cerium and the like; silicon oxide, aluminum oxide, magnesium oxide, Metal oxides such as zirconium oxide, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide, antimony oxide and cerium oxide; metal hydroxide such as aluminum hydroxide; metal carbonate such as magnesium carbonate Examples thereof include metal nitrides such as silicon nitride; resins such as acrylic resins, styrene resins, silicone resins, urethane resins, melamine resins, and epoxy resins. Materials of these light diffusing fine particles P _alpha may be used alone or in combination of two or more thereof. Among these light diffusing fine particles P _alpha materials, because it is excellent in handling properties during manufacture of the optical film, silicon, aluminum, magnesium, silicon oxide, aluminum oxide, magnesium oxide, aluminum hydroxide, magnesium carbonate, an acrylic resin, Styrene resin, silicone resin, urethane resin, melamine resin, and epoxy resin are preferable, and silicon oxide, aluminum oxide, aluminum hydroxide, magnesium carbonate, acrylic resin, styrene resin, silicone resin, urethane resin, melamine resin, and epoxy resin particles are used. More preferred are acrylic resins and silicone resins.

The refractive index of the light diffusing fine particles P _alpha is excellent in light extraction efficiency and front brightness of the surface light emitters, preferably 1.30 to 2.00, more preferably 1.35 to 1.90, 1.40～ 1.80 is more preferable.

The volume average particle size of the light diffusing fine particles P _alpha is preferably 0.5 ~ 10 m, more preferably 1μm~8μm, 1.5μm~6μm more preferred. When the volume average particle diameter of the light diffusing fine particles P _alpha is at 0.5μm or more, it can be effectively scatter light in the visible wavelength range. Further, the volume average particle diameter of the light diffusing fine particles P _alpha is at 20μm or less, it is possible to suppress the emission angle dependence of the emission wavelength of the surface light emitter.
The volume average particle diameter of each light diffusing fine particle in the present specification is a value measured by a laser diffraction scattering method.

The shape of the light diffusing fine particles P _alpha, for example, spherical, cylindrical, cubic, cuboid, pyramid, cone, star-shaped, irregular shape and the like. The shape of these light diffusing fine particles P _alpha may be used alone or in combination of two or more thereof. Among these shapes of the light diffusing fine particles P _alpha, since it is possible to effectively scatter the light in the visible wavelength range, spherical, cubic, rectangular parallelepiped, pyramid, preferably star-shaped, spherical is more preferable.

The matrix resin M _α and the light diffusing fine particles P _α have a refractive index difference, so that the effect of the light diffusing fine particles P _α is generated.
Refractive index difference between the matrix resin M _alpha and the light diffusing fine particles P _alpha is at least 0.12, preferably 0.12 to 0.30, 0.13 to 0.25 is more preferable. When the difference in refractive index between the matrix resin M _α and the light diffusing fine particles P _α is 0.12 or more, the front luminance of the surface light emitter is excellent, and the emission angle dependency of the emission light wavelength of the surface light emitter can be suppressed. it can. Further, the refractive index difference between the matrix resin M _alpha and the light diffusing fine particles P _alpha is 0.30 or less, excellent light extraction efficiency and front brightness of the surface light emitter.
When the light diffusing fine particles P _α are a mixture of two or more types of particles, the difference in refractive index between the two or more types of particles and the matrix resin M _α is 0.12 or more.
The refractive index of the light diffusing fine particles P _alpha is, since it is possible to suppress the emission angle dependence of the emission wavelength of the surface light emitter is preferably higher than the refractive index of the matrix resin M _alpha.

The combination of the matrix resin M _alpha and the light diffusing fine particles P _alpha is, the heat resistance of the optical film, mechanical properties, excellent moldability, a preferred range the refractive index difference is above, the surface light emitters light extraction efficiency and front brightness And the emission angle dependency of the emission light wavelength of the surface light emitter can be suppressed. Therefore, the matrix resin M _α is an acrylic resin, the light diffusion fine particles P _α are silicon oxide fine particles, and the matrix resin M _α is an acrylic resin. Diffusion fine particles P _α are aluminum oxide fine particles, matrix resin M _α is acrylic resin, light diffusion fine particles P _α are aluminum hydroxide fine particles, matrix resin M _α is acrylic resin, and light diffusion fine particles P _α are magnesium carbonate fine particles, matrix resin M _α. light acrylic resin but the light diffusing fine particles P _alpha acrylic resin fine particles in acrylic resin, the matrix resin M _alpha is Diffusing fine particles P _alpha styrene resin fine particles, the matrix resin M _alpha light diffusing fine particles P _alpha silicone resin fine particles in acrylic resin, the matrix resin M _alpha light diffusing fine particles P _alpha urethane resin fine particles in acrylic resin, the matrix resin M _alpha is Acrylic resin and light diffusing fine particles P _α are melamine resin fine particles, matrix resin M _α is acrylic resin and light diffusing fine particles P _α are preferably epoxy resin fine particles, matrix resin M _α is acrylic resin and light diffusing fine particles P _α are acrylic resin fine particles The matrix resin M _α is an acrylic resin and the light diffusing fine particles P _α are styrene resin fine particles, the matrix resin M _α is an acrylic resin and the light diffusing fine particles P _α are silicone resin fine particles, and the matrix resin M _α is an acrylic resin and the light diffusing fine particles P _α. There urethane resin fine particles, the matrix resin M _alpha there Light diffusing fine particles P _alpha melamine resin particles in Lil resin, more preferably the light diffusing fine particles P _alpha is an epoxy resin particles in the matrix resin M _alpha acrylic resin, the matrix resin M _alpha light diffusing fine particles P _alpha acrylic resin acrylic resin Fine particles, matrix resin M _α is acrylic resin and light diffusing fine particles P _α are silicone resin fine particles, matrix resin M _α is acrylic resin and light diffusing fine particles P _α are more preferably melamine resin fine particles, and matrix resin M _α is acrylic resin and light. diffusing fine particles P _alpha is particularly preferred melamine resin particles.

The content of the light diffusing fine particles P _alpha, compared matrix resin M _alpha 100 parts by weight, preferably 1 part by weight to 70 parts by weight, 5 parts by weight to 60 parts by mass is more preferable. When the content of the light diffusing fine particles P _alpha is at least 1 part by weight, excellent in front brightness of the surface light emitter, it is possible to suppress the emission angle dependence of the emission wavelength of the surface light emitter. If the content of the light diffusing fine particles P _alpha is less than 70 parts by mass, excellent light extraction efficiency and front brightness of the surface light emitter.

(Region β)
The region β is not particularly limited as long as the composition is different from that of the region α, but it is preferable that the region β includes the matrix resin M _β and, if necessary, the light diffusion particles P _β .

The matrix resin M _β constituting the region β may be the same as or different from the matrix resin M _α constituting the region α, but is excellent in light extraction efficiency and front luminance of the surface light emitter. Are preferably the same.
The same in this specification does not need to be exactly the same, and includes slightly different things.

Examples of the material of the matrix resin _Mβ include the same materials as those described above (region α), and the same ranges as described above are preferable for the same reasons as described above.
Regarding the light transmittance and refractive index of the matrix resin _Mβ , the same ranges as described above are preferable for the same reason as described above (region α).

The region β may or may not include the light diffusing fine particles P _β , but it is preferable that the region β is not included because of excellent light extraction efficiency of the surface light emitter.
The term “not included” as used herein includes not only those that are not included at all, but also those that are slightly included.

If the region beta contains light diffusing fine particles P _beta, the material of the light diffusing fine particles P _beta, the shape include those similar to the aforementioned (area alpha), preferably the same range as described above for the same reason as described above.
If the region beta contains light diffusing fine particles P _beta, the refractive index of the light diffusing fine particles P _beta, the volume average particle diameter is preferably the same range as described above for the same reason as the above (regions alpha).

If the region beta contains light diffusing fine particles P _beta, a combination of a matrix resin M _beta and the light diffusing fine particles P _beta has include those similar to the aforementioned (area alpha), similar to that described above for the same reason as described above A range is preferred.
If the region beta contains light diffusing fine particles P _beta, the refractive index difference between the matrix resin M _beta and the light diffusing fine particles P _beta is preferably the same range as described above for the same reason as the above (regions alpha).

The content of the light diffusing fine particles P _beta, compared matrix resin M _beta 100 parts by weight, preferably not more than 50 parts by weight, more preferably 25 parts by mass or less, 0 parts by weight is particularly preferred. When the content of the light diffusing fine particles P _beta is less than 50 parts by mass, excellent light extraction efficiency and front brightness of the surface light emitter.

The content of the light diffusing fine particles P _{α with} respect to 100 parts by mass of the matrix resin M _α is higher than the content of the light diffusing fine particles P _{β with} respect to 100 parts by mass of the matrix resin M _β because the light extraction efficiency of the surface light emitter is excellent. Is preferred.
The difference between the content of the light diffusing fine particles P _{α with} respect to 100 parts by mass of the matrix resin M _α and the content of the light diffusing fine particles P _{β with} respect to 100 parts by mass of the matrix resin M _β is excellent in the light extraction efficiency and front luminance of the surface light emitter. Since the emission angle dependence of the emission light wavelength of the surface light emitter can be suppressed, 5 parts by mass to 50 parts by mass are preferable, and 10 parts by mass to 40 parts by mass are more preferable.

  In addition to the matrix resin and the light diffusing fine particles, the region α and the region β may contain other additives as long as the performance of the optical film is not impaired.

  Other additives include, for example, release agents, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, antifoaming agents, leveling agents, antifouling improvers, dispersion stabilizers, viscosity modifiers, etc. Is mentioned.

  Since the content of the other additive can improve the properties of the other additive without impairing the performance of the optical film, in any of the regions α and β, the amount of the matrix resin is 100 parts by mass. 10 mass parts or less are preferable and 5 mass parts or less are more preferable.

(Base layer)
Since the optical film of the present invention supports the structure of the microlens, it is preferable to provide a base layer. Examples thereof include an optical film as shown in FIG.
The optical film 10 shown in FIG. 4 has a microlens layer 14 having a microlens 11 and a base layer 15.

  The thickness of the base layer is preferably 3 μm to 60 μm, and more preferably 5 μm to 50 μm, because the flexibility of the optical film and the adhesion to the substrate are excellent.

  The region α and the base layer may have the same or different material composition, but the material composition is preferably the same because the productivity of the optical film is excellent.

(Base material)
In order to keep the shape of the optical film on the light incident surface side of the optical film of the present invention, a substrate may be provided.
Since the base material is excellent in curability of the active energy ray-curable composition, a base material that transmits active energy rays is preferable.

  Examples of the material of the base material include acrylic resin; polycarbonate resin; polyester resin such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; styrene resin such as polystyrene and ABS resin; vinyl chloride resin; diacetyl cellulose, triacetyl cellulose, and the like. Cellulose resin; imide resin such as polyimide and polyimide amide; glass; metal. Among these base materials, acrylic resin, polycarbonate resin, polyester resin, styrene resin, vinyl chloride resin, cellulose resin, and imide resin are preferable because of excellent flexibility and excellent transmission of active energy rays. Resins, polycarbonate resins, polyester resins, and imide resins are more preferable, and polyester resins are more preferable.

  The thickness of the substrate is preferably 10 μm to 1000 μm, more preferably 20 μm to 500 μm, and even more preferably 25 μm to 300 μm, since the thickness of the substrate is excellent in the handleability of the optical film and the curability of the active energy ray curable composition.

In order to improve the adhesiveness with the optical film, the base material may be subjected to an easy adhesion treatment on the surface of the base material as necessary.
Examples of the method for easy adhesion treatment include a method for forming an easy adhesion layer made of a polyester resin, an acrylic resin, a urethane resin, or the like on the surface of the substrate, and a method for roughening the surface of the substrate.

  In addition to the easy adhesion treatment, the base material may be subjected to surface treatment such as antistatic, antireflection, and adhesion prevention between the base materials as necessary.

  The refractive index of the base material is preferably 1.30 to 2.00, more preferably 1.35 to 1.90, and more preferably 1.40 to 1.80, because the substrate has excellent light extraction efficiency and front luminance. Is more preferable.

(Adhesive layer)
An adhesive layer may be provided on the light incident surface side of the optical film in order to adhere to the EL element. In the case of having a base material, an adhesive layer may be provided on the surface of the base material.
Examples of the adhesive layer include a layer using a known adhesive.

(Protective film)
In order to improve the handleability of the optical film, a protective film may be provided on the light incident surface side or the light emitting surface side of the optical film. The protective film may be peeled off from the optical film or the like when an optical film or the like is attached to the surface of the EL element or used as a surface light emitter.
As a protective film, a well-known protective film etc. are mentioned, for example.

(Optical film manufacturing method)
Since the manufacturing method of the optical film of this invention can produce the optical film of this invention continuously, it is preferable to include the following process AD performed sequentially.
Step A: Rotate a roll mold having an outer peripheral surface on which a plurality of concave microlens transfer portions are arranged, and run the substrate along the outer periphery of the roll mold in the rotation direction of the roll mold while rotating the outer periphery of the roll mold Step of applying active energy ray-curable composition β to the surface and filling a part of the microlens transfer portion with active energy ray-curable composition β Step B: Active between the outer peripheral surface of the roll mold and the substrate Step of supplying energy ray curable composition α Step C: In the state where active energy ray curable composition α is sandwiched at least between the outer peripheral surface of the roll mold and the substrate, the outer peripheral surface of the roll mold and the substrate Step of irradiating and curing the active energy ray to the region between the steps Step D: Step of peeling the cured product obtained in Step C from the roll mold

As an apparatus used for the manufacturing method of the optical film of this invention, the apparatus 50 etc. which are shown in FIG. 5 etc. are mentioned, for example.
The apparatus used in the method for producing an optical film of the present invention is preferably the apparatus 50 shown in FIG. 5 because the optical film of the present invention can be produced continuously.
Note that the rotation direction and traveling direction of the roll mold 51 and the base material 21 in FIG. 5 are directions of arrows.

Hereinafter, the apparatus 50 shown in FIG. 5 will be described.
The active energy ray-curable composition β for constituting the region β, and if necessary, light diffusing fine particles and other additives are mixed in a desired blending amount, and the resulting mixture β is mixed with the first nozzle 52. Then, it is flattened by the first doctor blade 54 and applied to the outer peripheral surface of the roll mold 51 by the first coating roll 53.
The active energy ray-curable composition α for constituting the region α, the light diffusing fine particles, and if necessary, the light diffusing fine particles and other additives are mixed in a desired blending amount, and the resulting mixture α is mixed with the first mixture α. The liquid is discharged from the second nozzle 52 ′, flattened by the second doctor blade 54 ′, and applied to the substrate 21 by the second coating roll 53 ′.
The distance between the roll mold 51 and the nip roll 55 is adjusted to set the thickness of the base layer of the optical film.
While rotating the roll mold 51, the active energy beam irradiation device 56 irradiates and cures the area between the outer peripheral surface of the roll mold 51 and the substrate 21. By peeling the obtained cured product from the roll mold 51, the optical film 10 having the substrate 21 is obtained.

(Process A)
In step A, a roll mold having an outer peripheral surface on which a plurality of concave microlens transfer portions are arranged is rotated, and the base of the roll mold is moved along the outer periphery of the roll mold in the rotation direction of the roll mold. In this step, the active energy ray-curable composition β is applied to the outer peripheral surface, and a part of the microlens transfer portion is filled with the active energy ray-curable composition β.

  The viscosity of the mixture β containing the active energy ray-curable composition β is preferably 10 mPa · s to 3000 mPa · s, more preferably 20 mPa · s to 2500 mPa · s, because it is excellent in handleability during the production of the optical film. 30 mPa · s to 2000 mPa · s is more preferable.

  Examples of roll molds include molds such as aluminum, brass, and steel; resin molds such as silicone resin, urethane resin, epoxy resin, ABS resin, fluororesin, and polymethylpentene resin; molds obtained by plating the resin; resin And a mold made of a material in which various metal powders are mixed. Among these roll molds, a mold is preferable because of excellent heat resistance and mechanical strength and suitable for continuous production. Specifically, the mold is preferable in many respects such as excellent durability against polymerization heat generation, hardly deformed, hardly scratched, temperature-controllable, and suitable for precision molding.

The roll mold has a concave transfer portion corresponding to the convex shape in order to transfer and form the convex microlenses of the optical film.
Examples of the method for producing the transfer portion include cutting with a diamond tool, etching as described in International Publication No. 2008/069324 pamphlet, and the like. Among these methods for manufacturing a transfer portion, when forming a concave shape having a curved surface such as a spherical shape, etching as described in International Publication No. 2008/69324 is performed because of excellent roll-type productivity. Preferably, when forming a concave shape that does not have a curved surface such as a pyramid shape, cutting with a diamond bite is preferable because the productivity of the roll mold is excellent.
In addition, as a method for manufacturing the transfer portion, a cylindrical roll die is manufactured by winding a metal thin film produced by electroforming from a master die having a depression and an inverted protrusion of the transfer portion around a roll core member. Can be used.

  In order to maintain the surface temperature, heat source equipment such as a sheathed heater or a hot water jacket may be provided inside or outside the roll mold as necessary.

  The rotation speed of the roll mold, that is, the running speed of the outer peripheral surface of the roll mold is preferably 0.1 m / min to 50 m / min, and preferably 0.3 m / min to 40 m / min, because of excellent moldability and productivity of the optical film. More preferably, 0.5 m / min to 30 m / min is even more preferable.

When the mixture β containing the active energy ray-curable composition β is applied in a roll shape, it is preferable to apply the mixture β after flattening, since air bubbles in the microlens can be suppressed.
Examples of the flattening means include a doctor blade, an air blade, an air knife, a roll coater, and a bar coater. These flattening means may be used alone or in combination of two or more. Among these flattening means, a doctor blade is preferable because air bubbles in the microlens can be suppressed.

  As described above, since the role of the region β in the optical film is sufficiently fulfilled, it is preferable to cover the region α as much as possible with the region β. For this purpose, the application of the mixture β containing the active energy ray-curable composition β is preferably an application for causing the mixture β to follow the surface of the concave microlens transfer portion on the outer peripheral surface of the roll type. In other words, the application of the mixture β to the surface of the microlens transfer portion during application means that the mixture β flows while being pressed against the surface of the microlens transfer portion, thereby copying at least a part of the surface of the microlens transfer portion. It means that it becomes a convex surface.

As a coating method for causing the mixture β to follow the surface of the microlens transfer portion, for example, while pressing a doctor blade, a roll coater or a bar coater having a tapered sharp tip against a rotating roll surface, a bank of the mixture β A shearing force is applied to the mixture β by the peripheral edge of the concave microlens transfer portion and a doctor blade, roll coater or bar coater, resulting in surface tension on the surface of the mixture β following the concave shape. The method etc. which comes to act are mentioned.
Thereby, generation | occurrence | production of the bubble in an optical film can be suppressed, area | region (alpha) can be covered with area | region (beta) as much as possible, and the role of area | region (beta) in an optical film can fully be fulfill | performed.

(Process B)
Step B is a step of supplying the active energy ray-curable composition α between the outer peripheral surface of the roll mold and the substrate.

  The viscosity of the mixture α containing the active energy ray-curable composition α is preferably 10 mPa · s to 3000 mPa · s, more preferably 20 mPa · s to 2500 mPa · s, because it is excellent in handleability during the production of the optical film. 30 mPa · s to 2000 mPa · s is more preferable.

  The mixture α containing the active energy ray-curable composition α may be supplied by being applied to a traveling substrate, or supplied to a roll mold coated with the mixture β containing the active energy ray-curable composition β. However, since the thickness of the base layer can be controlled, it is preferable that the base layer is coated and supplied.

When applying the mixture α containing the active energy ray-curable composition α to the substrate, it is preferable to apply the mixture α after flattening it because air bubbles in the microlens can be suppressed.
Examples of the flattening means include a doctor blade, an air blade, an air knife, a roll coater, and a bar coater. These flattening means may be used alone or in combination of two or more. Among these flattening means, a bar coater is preferable because air bubbles in the microlens can be suppressed.

(Process C)
Step C irradiates the region between the roll-type outer peripheral surface and the substrate with active energy rays in a state where at least the active energy ray-curable composition α is sandwiched between the roll-type outer peripheral surface and the substrate. And curing.

Before the step C, a step of irradiating the active energy ray to the mixture β containing the active energy ray-curable composition β and curing it may be included.
By going through the above steps, the interface between the region α and the region β becomes clear.
On the other hand, if the process is not performed, the vicinity of the interface between the region α and the region β is gradationized, and the vicinity of the interface between the region α and the region β becomes a region including both the component of the region α and the component of the region β. .

  Examples of the active energy ray include ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable because the active energy ray-curable composition is excellent in curability and can suppress deterioration of the optical film.

  Examples of the active energy ray light source include a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an electrodeless ultraviolet lamp, a visible light halogen lamp, and a xenon lamp.

Integrated light quantity of active energy rays, good curing of the active energy ray-curable composition, since it is possible to suppress deterioration of the optical film is preferably ^{0.01J / cm 2 ~10J / cm 2} , 0.5J / Cm ^{2 to} 8 J / cm ² is more preferable.

(Process D)
Step D is a step of peeling the cured product obtained in Step C from the roll mold.

  In order to make it easy to peel the cured product from the roll mold, the roll mold may be subjected to a peeling treatment, and a release agent may be included in the mixture α or the mixture β.

  Regarding the method for producing the optical film of the present invention, it is also possible to refer to the description in the pamphlet of International Publication No. 2013/080794.

(Surface emitter)
The surface light emitter of the present invention includes the optical film of the present invention and an EL element.
Examples of the surface light emitter of the present invention include a surface light emitter shown in FIG.
The surface light emitter shown in FIG. 6 is optically coupled to the surface of the glass substrate 31 of the EL element 30 in which the glass substrate 31, the anode 32, the light emitting layer 33, and the cathode 34 are sequentially laminated via the adhesive layer 22 and the base material 21. A film 10 is laminated.

Since the surface light emitter of the present invention includes the optical film of the present invention, the surface light emitter is excellent in light extraction efficiency and front luminance, and suppresses the output angle dependency of the output light wavelength.
Therefore, the surface light emitter of the present invention can be suitably used for, for example, illumination, a display, a screen, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

(Measurement of light extraction efficiency)
The surface light emitters obtained in the examples, comparative examples, and reference examples were placed on the sample stage of the hemispherical total luminous flux measurement system (model name “HM series”, spectrometer “MCPD9800”, manufactured by Otsuka Electronics Co., Ltd.). A diffusion sheet (trade name “MC-PET”, Furukawa Electric Co., Ltd.) is used around the surface light emitters obtained in Examples, Comparative Examples, and Reference Examples so that light from the outer periphery of the surface light emitter does not enter the hemispheric integrating sphere. Covered by Kogyo Co., Ltd. (thickness 1 mm). In this state, a current of 100 mA was passed through the organic EL element to cause the surface light emitters obtained in the examples, comparative examples, and reference examples to emit light, and the total luminous flux emitted from the light emitting surface was measured.
When the number of photons of the surface light emitter obtained in the reference example was 100%, the ratio of the number of photons of the surface light emitter obtained in the example was defined as the light extraction efficiency.

(Measurement of front brightness)
A current of 100 mA was applied to the surface emitting organic EL elements obtained in the examples, comparative examples, and reference examples to emit light, and a spectral luminance meter (model name “MCPD-7700”, manufactured by Otsuka Electronics Co., Ltd.) was used. The luminance value of the light emitted in the normal direction of the light emitting surface was measured.
When the luminance value of the surface light emitter obtained in the reference example was 100%, the ratio of the luminance value of the surface light emitter obtained in the example was defined as the front luminance.

(Measurement of chromaticity change)
A current of 100 mA was applied to the surface emitting organic EL elements obtained in the examples, comparative examples, and reference examples to emit light, and a spectral luminance meter (model name “MCPD-7700”, manufactured by Otsuka Electronics Co., Ltd.) was used. In addition, the chromaticities u ′ and v ′ of the u′v ′ color system were measured every 2 degrees from 0 degrees to 80 degrees when the normal direction of the light emitting surface was 0 degrees. The value of u ′ and the average value of u ′ for each angle are plotted on the horizontal axis, the value of v ′ and the average value of v ′ for each angle are plotted on the vertical axis, and the average value of u ′ and the average value of v ′ are plotted. The distance from the plotted point to the plotted point of the value of u ′ of each angle and the value of v ′ of each angle was calculated, and the value when the distance was the longest was defined as the amount of chromaticity change.
The smaller the chromaticity change amount, the more the emission angle dependency of the emission light wavelength of the surface light emitter is suppressed.

(material)
Matrix resin A: cured product of active energy ray-curable composition produced in Production Example 1 described later (refractive index 1.52)
Light diffusing fine particles A: melamine resin spherical fine particles (trade name “2000M”, manufactured by Nissan Chemical Industries, Ltd., refractive index 1.65, volume average particle diameter 2 μm)
Light diffusion fine particle B: Silicone resin spherical fine particle (trade name “TSR9000”, manufactured by Mentive Performance Materials, refractive index 1.42, volume average particle diameter 2 μm)
Organic EL element A: Organic EL element from which the light extraction member on the light emitting surface side of the organic EL lighting module (trade name “OLE-P0909-L3”, manufactured by Pioneer OLED Lighting Device Co., Ltd.) is peeled off

[Production Example 1]
(Production of mixture A and mixture B)
In a glass flask, 117.6 g (0.7 mol) of hexamethylene diisocyanate as a diisocyanate compound, 151.2 g (0.3 mol) of an isocyanurate type hexamethylene diisocyanate trimer, 2 as a hydroxyl group-containing (meth) acrylate 128.7 g (0.99 mol) of hydroxypropyl acrylate and 693 g (1.54 mol) of pentaerythritol triacrylate, 22.1 g of di-n-butyltin dilaurate as a catalyst, and 0.55 g of hydroquinone monomethyl ether as a polymerization inhibitor The mixture was heated to 75 ° C., stirred while maintaining the temperature at 75 ° C., reacted until the concentration of the residual isocyanate compound in the flask was 0.1 mol / L or less, cooled to room temperature, A functional acrylate was obtained.
35 parts by mass of the obtained urethane polyfunctional acrylate, 20 parts by mass of polybutylene glycol dimethacrylate (trade name “Acryester PBOM”, manufactured by Mitsubishi Rayon Co., Ltd., number average molecular weight 650), diethylene oxide adduct of bisphenol A 40 parts by mass of (meth) acrylate (trade name “New Frontier BPEM-10”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), phenoxyethyl acrylate (trade name “New Frontier PHE”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5 The active energy ray-curable composition was obtained by mixing 1 part by mass and 1.2 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name “Irgacure 184”, manufactured by BASF).
100 parts by mass of the obtained active energy ray-curable composition and 43 parts by mass of the light diffusing fine particles A were mixed to obtain a mixture A. Further, the obtained active energy ray-curable composition was designated as a mixture B.

[Production Example 2]
(Manufacture of roll molds)
Copper plating with a thickness of 200 μm and a Vickers hardness of 230 Hv was applied to the outer peripheral surface of a steel roll having an outer diameter of 200 mm and an axial length of 320 mm. A transfer part in which a photosensitizer is applied to the surface of the copper plating layer, laser exposure, development and etching are performed, and hemispherical depressions having a diameter of 50 μm and a depth of 25 μm are arranged in a hexagonal array at a minimum interval of 3 μm on the copper plating layer. A formed mold was obtained. In order to impart rust prevention and durability to the surface of the obtained mold, chromium plating was applied to obtain a roll mold.

[Reference example]
The organic EL element A was used as a surface light emitter as it was. Table 1 shows the evaluation results of the optical characteristics of the surface light emitters used.

[Example 1]
While rotating the roll mold obtained in Production Example 2 and running a polyethylene terephthalate base material (trade name “Cosmo Shine A4100”, manufactured by Toyobo Co., Ltd.) in the rotation direction of the roll mold along the outer peripheral surface of the roll mold Then, 43% by volume of the mixture B was applied to the outer peripheral surface of the roll mold, and a part of the microlens transfer portion was filled with the mixture B. Next, 57% by volume of the mixture A is applied between the outer peripheral surface of the roll mold and the traveling base material, and the mixture A and the mixture B are sandwiched in the region between the outer peripheral surface of the roll mold and the base material. And cured by irradiation with ultraviolet rays. The obtained cured product was peeled from the roll mold to obtain an optical film.
The composition in the microlens was 44% by volume of the cured product of the mixture A and 56% by volume of the cured product of the mixture B. The thickness of the base layer was 6 μm. Furthermore, from the photograph of the surface of the optical film having microlenses taken with an electron microscope, the ratio of the area of the bottom surface of the microlens to the area of the optical film was 70%.
Cargill standard refraction liquid (refractive index 1.52, manufactured by Moritex Co., Ltd.) is applied as an adhesive layer on the light emitting surface side of the organic EL element A, and the light emitting surface of the organic EL element A and the surface of the base material are applied. A surface light emitter was obtained by optical adhesion. Table 1 shows the evaluation results of the optical characteristics of the obtained surface light emitter.

[Examples 2 to 4, Comparative Examples 1 to 3]
A surface light emitter was obtained in the same manner as in Example 1 except that the composition and the thickness of the base layer were changed as shown in Table 1. Table 1 shows the evaluation results of the optical characteristics of the obtained surface light emitter.
In any of the examples and comparative examples, the composition in the microlens is 44% by volume of the cured product constituting the region α, and 56% by volume of the cured product of the mixture constituting the region β. The coating amount of the mixture was adjusted.

The surface light emitters obtained in Examples 1 to 4 were excellent in light extraction efficiency and front luminance, and were able to suppress the emission angle dependency of the emission light wavelength.
On the other hand, the surface light emitters obtained in Comparative Examples 1 to 3 have a small difference between the refractive index of the matrix resin M _α constituting the region α and the refractive index of the light diffusing fine particles P _α included in the region α, and the front luminance. The output angle dependency of the output light wavelength could not be suppressed.

  Since the optical film of the present invention improves the light extraction efficiency and front luminance of the surface light emitter and suppresses the emission angle dependency of the emission light wavelength of the surface light emitter, the surface light emitter including the optical film of the present invention is For example, it can be suitably used for lighting, a display, a screen and the like.

10 optical film 11 micro lens 12 region α
13 region β
DESCRIPTION OF SYMBOLS 14 Microlens layer 15 Base layer 16 Bottom part of microlens 21 Base material 22 Adhesive layer 30 EL element 31 Glass substrate 32 Anode 33 Light emitting layer 34 Cathode 50 Device 51 Roll type 52 1st nozzle 52 '2nd nozzle 53 2nd nozzle 53 1 coating roll 53 ′ second coating roll 54 first doctor blade 54 ′ second doctor blade 55 nip roll 56 active energy ray irradiation device

Claims (10)

A plurality of convex microlenses are arranged,
The microlens has a region α and a region β,
The area β occupies the convex outer part of the microlens and is an optical film positioned so as to cover the area α,
The region α includes a matrix resin M _α and light diffusion fine particles P _α ,
An optical film in which the difference between the refractive index of the matrix resin M _α constituting the region α and the refractive index of the light diffusing fine particles P _α included in the region α is 0.12 or more. The optical film according to claim 1, wherein the refractive index of the light diffusing fine particles P _α contained in the region α is higher than the refractive index of the matrix resin M _α constituting the region α. The matrix resin M _α constituting the region α is an acrylic resin,
The optical film according to claim 1, wherein the light diffusing fine particles P _α contained in the region α is a melamine resin. The content of the light diffusing fine particles _Pα contained in the region α is 1 part by mass to 70 parts by mass with respect to 100 parts by mass of the matrix resin M _α constituting the region α. Optical film. Matrix resin M _beta constituting the matrix resin M _alpha and regions beta constituting a region alpha is the same resin, the optical film according to claim 1. Region beta does not contain the light diffusing fine particles P _beta, optical film according to claim 1.   The shape of the microlens is at least one of a spherical notch shape, a spherical notch shape, an ellipsoidal spherical notch shape, an ellipsoidal spherical notch shape, a pyramid shape, and a truncated pyramid shape. The optical film as described.   The surface light-emitting body containing the optical film and surface light source in any one of Claims 1-7. The manufacturing method of the optical film in any one of Claims 1-7 including following process AD performed sequentially.
Step A: Rotate a roll mold having an outer peripheral surface on which a plurality of concave microlens transfer portions are arranged, and run the substrate along the outer periphery of the roll mold in the rotation direction of the roll mold while rotating the outer periphery of the roll mold Step of applying active energy ray-curable composition β to the surface and filling a part of the microlens transfer portion with active energy ray-curable composition β Step B: Active between the outer peripheral surface of the roll mold and the substrate Step of supplying energy ray curable composition α Step C: In the state where active energy ray curable composition α is sandwiched at least between the outer peripheral surface of the roll mold and the substrate, the outer peripheral surface of the roll mold and the substrate Step of irradiating and curing the active energy ray to the region between the steps Step D: Step of peeling the cured product obtained in Step C from the roll mold   The application of the active energy ray-curable composition β in the step A is an application of causing the active energy ray-curable composition β to follow the surface of the concave microlens transfer portion on the outer peripheral surface of the roll type. Manufacturing method of the optical film.