JP2009032463A - Light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element with high luminance and excellent durability. <P>SOLUTION: A light-control film comprises a film obtained by forming a thin film on at least one surface of a transparent base material to obtain a laminated body and by contracting the laminated body in at least one in-plane axial direction to bend the thin film to have a plurality of rib-like convex lens parts on at least one of the surfaces, wherein tip parts of the rib-like convex lens parts take on a upward convex curved face, and a ratio (length/width) of a length to a width of each rib of the rib-like convex lens parts is 5 or more. A light-emitting element is obtained by installing the light-control film at a light-irradiating side of an organic EL element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device. More specifically, the present invention relates to a light emitting device having high luminance and excellent durability.

  Organic EL elements are expected to be applied as light sources for display devices such as segment display devices, dot matrix display devices, and liquid crystal display devices. As an example of an organic electroluminescence (EL) element, a structure in which a hole transport layer and a light emitting material layer are formed between a hole injection electrode serving as an anode and an electron injection electrode serving as a cathode (SH-A structure) A structure in which a light emitting material layer and an electron transport layer are formed between a hole injection electrode and an electron injection electrode (SH-B structure), or between a hole injection electrode and an electron injection electrode There is a structure in which a hole transport layer, a light emitting material layer, and an electron transport layer are formed (DH structure).

  Regardless of the structure, the organic EL element has a light emitting material layer and a hole (or electron) transport layer in which holes injected from a hole injection electrode (anode) and electrons injected from an electron injection electrode (cathode) are used. It operates on the principle that light is emitted by recombination within the interface and the light emitting material layer. Therefore, compared with an inorganic EL element whose light emission mechanism is collision erection type light emission, the organic EL element has a feature that it can emit light at a low voltage, and is very promising as a light emitting element in the future.

  FIG. 1 shows a configuration example of a typical organic EL element. The organic EL element shown in FIG. 1 includes a transparent substrate 110, a lower electrode layer 111, a light emitting material layer 112, an upper electrode layer 113, and a sealing layer 114. The conventional organic EL element has a method of emitting light emitted from the light emitting material layer 112 from the transparent substrate 110 side (bottom emission method). However, since a thin film transistor is installed on the transparent substrate side, the light emission area is small. Become. Therefore, recently, a method of emitting light from the opposite side of the transparent substrate 110 when viewed from the light emitting material layer 112 (top emission method) has been attracting attention because a sufficient light emission area can be obtained.

  The luminance of a light emitting element using an organic EL element increases in proportion to the amount of current. However, when the amount of current is increased, the power consumption increases, and the characteristics of the organic EL element are deteriorated over time, thereby shortening the life of the organic EL element. If light emitted from the light-emitting material layer can be efficiently extracted outside, high luminance can be achieved even with a low current amount.

  In order to increase the light extraction efficiency, for example, Patent Document 1 includes a light source composed of an organic electroluminescence element, a reflection member that condenses light from the light source, and a light diffusion film for extracting light. Lighting devices have been proposed. This light diffusion film is formed by interspersing fine beads having a refractive index different from those in a base material made of a material having a refractive index substantially equal to the refractive index of the glass substrate. However, the light diffusing film containing particles and fibers has a characteristic of uniformly diffusing incident light in each direction indiscriminately, resulting in a reduction in front luminance. Patent Document 2 or 3 describes an EL device that includes a light emitting unit made of an organic EL element and a prism sheet in which prisms are formed at a predetermined pitch. However, since the prism sheet collects light by the inclined surface of the prism, the brightness is lowered when the prism surface is scratched by friction or the like.

JP 2007-13913 A JP 2007-5277 A JP 2004-265851 A

  An object of the present invention is to provide a light-emitting element having high luminance and excellent durability.

  As a result of studying to solve the above problems, the present inventors have found that at least one surface has a ratio of length to width of the ridge (length / width) of 5 or more and a ridge having a convex top. Based on this finding, it is found that a light-emitting element having high luminance and excellent durability can be obtained by providing a light-controlling film having a plurality of ridge-shaped convex lens portions on the light-emitting side of an organic electroluminescence element. The present invention has been completed.

That is, the present invention includes the following aspects.
(1) At least one surface has a plurality of ridge-like convex lens portions in which the ratio of the ridge length to the width (length / width) is 5 or more and the top of the ridge forms a convex curved surface. A light emitting device comprising a light control film on a light output side of an organic electroluminescence device.
(2) As for the said light control film, the average value Xp of the space | interval between ridge-like convex lens parts is 0.2-40 micrometers, and the standard deviation (sigma) p of the space | interval between ridge-like convex lens parts is (sigma) p / Xp = The said light emitting element which is 0.1-0.9.
(3) The light-emitting device, wherein the light control film has a total light transmittance of 70% or more and a haze of 70% or more.
(4) The light control film further includes a thin film layer that is laminated on the bowl-like convex lens part and is bent so as to correspond to the shape of the bowl-like convex lens part, and a surface of the thin film layer is the bowl The light emitting device as described above, which is undulated by the raised shape of the convex lens portion.
(5) The light-emitting element, wherein the light control film has a plurality of micro protrusions spaced apart by an average distance between vertices shorter than an average distance between vertices of the hook-shaped convex lens portion on the undulating surface of the thin film layer.
(6) The said light emitting element in which an organic electroluminescent element is a thing formed by laminating | stacking a board | substrate, a lower electrode layer, a luminescent material layer, an upper electrode layer, and a sealing layer one by one.

  The light-emitting element of the present invention can emit light with high luminance at a wide angle. Further, even after long-time light emission, there is little decrease in luminance, excellent durability, and long life. The light-emitting element of the present invention is useful as a light source for display devices such as segment display devices, dot matrix display devices, and liquid crystal display devices.

It is sectional drawing which shows the typical structural example of an organic EL element. The figure which shows the surface scanning electron micrograph image of the uneven surface of the light control film of Example 1 The figure which shows the vertical cross section image of the light control film of Example 1 The figure which shows the surface scanning electron micrograph image of the uneven surface of the light control film of Example 2 The figure which shows the surface scanning electron micrograph image of the uneven surface of the light control film of Example 3 The figure which shows the surface scanning electron micrograph image of the uneven surface of the light control film of Example 4 The figure which shows the vertical cross-section image of the light control film of Example 4 Cross-sectional schematic diagram of structural example of light control film Cross-sectional schematic diagram of structural example of light control film Diagram showing a configuration example of a bottom emission type light emitting element

Explanation of symbols

1,11: Base layer (film substrate)
2, 12: Optical functional layer (optical functional film)
100: Light control film 110: Substrate 111: Lower electrode layer (anode)
112: Luminescent material layer 113: Upper electrode layer (cathode)
114: Sealing layer

  The light emitting device of the present invention has a plurality of ridge-like convex lenses in which the ratio (length / width) of the ridge length to the width is 5 or more on at least one surface and the top of the ridge has a convex curved surface upward The light control film which has a part is provided in the light emission side of an organic electroluminescent element.

[Light control film]
The light control film used in the present invention has a plurality of ridge-like convex lens portions on at least one surface.

As shown in FIG. 2 or FIGS. 4 to 6, the hook-shaped convex lens portion is constituted by an elongated hook. The ratio (length / width) between the length and width of the ridge is 5 or more. The length of the ridge is the length of the ridgeline, and the width is a width at a height that is ½ of the height of the ridge.
In addition, the top of the ridge has an upwardly convex curved surface. Therefore, the vertical cross section of the top of the ridge has an upwardly convex curved shape such as a semicircular shape, a semielliptical shape, and a parabolic shape.
It is preferable that the radius of curvature of the apex of the saddle-like convex lens portion is different between adjacent saddle-like convex lens portions. The average value Xr of the radius of curvature of the apex of the bowl-shaped convex lens portion is preferably 0.1 μm or more, more preferably 0.5 to 60 μm. The standard deviation σr of the radius of curvature is preferably (σr / Xr =) 0.05 to 0.8 and more preferably 0.1 to 0.6 with respect to Xr. The standard deviation in the present invention is a sample standard deviation. When Xr and σr / Xr are within this range, the distribution of the light converging direction of each ridge-shaped convex lens portion is moderately widened, so that the balance between the expansion of the viewing angle and the luminance improvement is good.
Furthermore, the average value of the ratio (= height / interval = aspect ratio) of the height of the saddle-like convex lens portion and the interval between the saddle-like convex lens portions is preferably 0.1 to 4.0, more preferably 0.5. ~ 2.0. The radius of curvature of the apex can be obtained by fitting the top structure by image processing or the like with an electron microscope or the like.

  The average value Xp of the interval between the ridge-like convex lens portions is preferably 0.2 to 40 μm, more preferably 1.0 to 30 μm. Further, the standard deviation σp of the interval between the ridge-like convex lens portions is preferably (σp / Xp =) 0.1 to 0.9, more preferably 0.2 to 0.7, with respect to Xp. preferable. When Xp and σp / Xp are within this range, the balance between the luminance improvement due to the light condensing property and the expansion of the viewing angle due to the light diffusibility becomes good. In addition, the space | interval between saddle-shaped convex lens parts is a distance between vertices. As shown in FIG. 5, the hook-shaped convex lens portion may be one in which the direction in which the eyelids extend is randomly oriented, or the direction in which the eyelids extend is aligned in one direction as shown in FIG. There may be.

  When the hook-like convex lens portions are aligned in one direction as shown in FIG. 2 or FIG. 4, anisotropy (anisotropic diffusion) can be imparted to the diffusion direction of the incident light. In addition, anisotropic diffusivity is obtained by investigating the relationship between the brightness and the emission angle of light that has passed through a light control film and parallel light such as collimated light and transmitted in a direction having a periodicity and a direction perpendicular thereto. It can be measured. The anisotropic diffusivity of the film can be appropriately selected according to desired characteristics, and the anisotropic diffusivity can be adjusted by changing the regularity of the ridge-like convex lens portion. For example, when it is desired to increase the anisotropic diffusibility of the incident light, a highly regular state as shown in FIG. In addition, the side surface (bottom surface) of the bowl-shaped convex lens portion may be a surface perpendicular to the main surface of the film, may have an overhang (reverse taper structure), or may have a gently inclined surface. It may be.

  The saddle-like convex lens portion is formed by a bulge or depression on the film surface. That is, the saddle-like convex lens portion in the present invention is essentially different from the convex portion formed by attaching resin or the like to the surface of a flat base film.

The film having the ridge-like convex lens portion is usually made of resin, rubber or elastomer.
Examples of the resin include styrene resin, acrylic resin, methacrylic resin, organic acid vinyl ester resin, vinyl ether resin, halogen-containing resin, olefin resin, alicyclic olefin resin, polycarbonate resin, and polyester resin. , Polyamide resins, thermoplastic polyurethane resins, polysulfone resins (eg, polyethersulfone, polysulfone, etc.), polyphenylene ether resins (eg, polymers of 2,6-xylenol), cellulose derivatives (eg, cellulose esters) , Cellulose carbamates, cellulose ethers, etc.), silicone resins (eg, polydimethylsiloxane, polymethylphenylsiloxane, etc.).

  Examples of the alicyclic olefin-based resin include cyclic olefin random copolymers described in JP-A No. 05-310845 and US Pat. No. 5,179,171, JP-A No. 05-97978 and US Pat. No. 5,202,388. Examples thereof include hydrogenated polymers described in the publication, thermoplastic dicyclopentadiene-based ring-opening polymers described in JP-A-11-124429 and WO99 / 20676, and hydrogenated products thereof. .

  Examples of the rubber / elastomer include diene rubbers such as polybutadiene and polyisoprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, acrylic rubber, urethane rubber, and silicone rubber. Of these, a thermoplastic resin is preferred from the viewpoint of easy film production.

  The thermoplastic resin preferably used for the film having a ridge-like convex lens portion is not particularly limited, but a glass transition temperature of 60 to 200 ° C. is preferable and 100 to 180 ° C. from the viewpoint of ease of processing. More preferred. The glass transition temperature can be measured by differential scanning calorimetry (DSC).

  The thermoplastic resin has a polystyrene-equivalent weight average molecular weight of preferably 5,000 to 500,000, more preferably 8,000 to 200,000, and particularly preferably 10,000 to 100,000. When the weight average molecular weight is within this range, molding processability is improved and mechanical strength can be improved. This weight average molecular weight can be measured by gel permeation chromatography.

  Resin, rubber, or elastomer constituting a film having a ridge-like convex lens part is a colorant such as a pigment or dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, Antioxidants, chlorine scavengers, flame retardants, crystallization nucleating agents, antiblocking agents, antifogging agents, mold release agents, organic or inorganic fillers, neutralizing agents, lubricants, decomposition agents, metal deactivators, Contaminants, fluorescent brighteners, antibacterial agents, light diffusing particles, thermoplastic elastomers and other compounding agents may be appropriately blended.

It is preferable that the light control film used in the present invention further includes a thin film layer that is laminated on the ridge-like convex lens portion on the film surface and is bent so as to correspond to the shape of the ridge-like convex lens portion.
The thin film layer is formed of an organic material or an inorganic material.
Examples of the inorganic substance constituting the thin film layer include metal compounds such as metal oxides and metal nitrides, and nonmetal compounds such as nonmetal oxides and nonmetal nitrides. Specifically, aluminum, silicon, Metals or non-metals such as magnesium, palladium, platinum, zinc, tin, nickel, silver, copper, gold, antimony, yttrium, indium, stainless steel, chromium, titanium, tantalum, zirconium, niobium, lanthanum, cerium, etc .; or these Or oxides or nitrides thereof, or a mixture thereof. Among these, it is preferable to select an inorganic substance that transmits visible light. Specific examples thereof include ITO, In ₂ O ₃ , SnO ₂ , SiO ₂ , CuI, TiO ₂ , and ZrO ₂ . Of these, SiO ₂ is preferable from the viewpoint of the flexibility of the thin film.

  The average thickness of the inorganic thin film is preferably 1 nm to 500 nm. If the thickness is less than 1 nm, it is difficult to form the hook-shaped convex lens portion, and if the thickness is more than 500 nm, the thin film tends to crack. When an inorganic thin film is used, a fine ridge-shaped convex lens portion having an average interval Xp of 100 nm to 1000 nm can be easily obtained.

Examples of the organic substance constituting the thin film layer include thermoplastic resins and curable resins.
As a thermoplastic resin, the thing similar to what was illustrated as what can be used for the film which has the said saddle-like convex lens part can be mentioned. The organic thin film may contain a compounding agent as in the case of the resin used for the film having the ridge-like convex lens portion.

  In the present invention, when the film having the ridge-like convex lens portion is made of the thermoplastic resin 1 and the organic thin film is made of the thermoplastic resin 2, the glass transition temperature of the thermoplastic resin 2 is the thermoplastic resin 1. It is preferably 20 ° C. or higher than the glass transition temperature. The glass transition temperature can be measured by differential scanning calorimetry (DSC).

  The curable resin includes a thermosetting resin and an energy beam curable resin. In addition, an energy ray means visible light, an ultraviolet-ray, an electron beam, etc.

  Specific examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, silicon Examples thereof include resins and polysiloxane resins.

  Although it does not specifically limit as said energy beam curable resin, For example, the low molecular weight compound or resin etc. which have a radically polymerizable unsaturated group and / or a cation polymerizable group are mentioned, It can select suitably by a desired characteristic. In addition, the radically polymerizable unsaturated group and / or the cation polymerizable group may contain two or more in one molecule.

  Examples of the low molecular weight compound having a radical polymerizable unsaturated group include α-olefins such as ethylene and propylene; conjugated diene compounds such as butadiene and isoprene; styrene, α-methylstyrene, t-butylstyrene, divinylbenzene, and vinylnaphthalene. Radical-reactive aromatic compounds such as 4-vinylpyridine; acrylic acid, methacrylic acid, fumaric acid, maleic acid, endo-bicyclo [2.2.1] -5-heptene-2,8-dicarboxylic acid (endic Acid), tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid and other unsaturated carboxylic acids; acrylic acid chloride, methacrylic acid chloride, myic acid chloride and other unsaturated carboxylic acid halides; acrylamide, methacrylamide , Maleimide, etc. Amide or imide derivative of saturated carboxylic acid; anhydride of the unsaturated carboxylic acid such as maleic anhydride, endic acid anhydride, citraconic anhydride; monomethyl maleate, dimethyl maleate, (meth) acrylic acid amide, methyl (meta ) Acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (Meth) acrylate, dicyclopentenyl (meth) acrylate, allyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, hexane All di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, trimethylol propantoso (meth) acrylate, propionic acid / dipentaerythritol tri ( Ester derivatives of unsaturated carboxylic acids such as (meth) acrylate, propionic acid / dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate; vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, Radical reaction unsaturated groups such as p-styryltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxytriethoxysilane, etc. And the like.

  Examples of the low molecular weight compound having a cationic polymerizable group include dicyclopentadiene dioxide, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexanecarboxylate, bis (2,3-epoxycyclopentyl) ether, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, (3,4-epoxy-6-methylcyclohexyl) methyl-3,4-epoxy-6-methyl Cyclohexane carboxylate, bis (3,4-epoxycyclohexylmethyl) acetal, bis (3,4-epoxycyclohexyl) ether of ethylene glycol, 3,4-epoxycyclohexanecarboxylic acid diester of ethylene glycol, etc. Compounds containing xyl groups; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, Epoxy compounds containing a glycidyl group such as 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, diglycerin tetraglycidyl ether, trimethylolpropane triglycidyl ether, spiroglycol diglycidyl ether; 3-ethyl-3-methoxymethyloxetane 3-ethyl-3-ethoxymethyloxetane, 3-ethyl-3-butoxymethyloxetane, 3-ethyl-3 Allyloxymethyloxetane, 3-methyl-3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2′-hydroxyethyl) oxymethyloxetane, 3-ethyl-3- (2 '-Hydroxy-3'-phenoxypropyl) oxymethyloxetane, 3-ethyl-3- (2'-hydroxy-3'-butoxypropyl) oxymethyloxetane, 3-ethyl-3- [2'-(2 "- Compounds containing an oxetane ring such as ethoxyethyl) oxymethyl] oxetane; and the like.

  Examples of the resin having a radical polymerizable unsaturated group or a cationic polymerizable group include low molecular weight polyester resins, polyether resins, acrylic resins, methacrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, Examples thereof include resins having a radically polymerizable unsaturated group or a cationically polymerizable group in the side chain such as a polythiol polyene resin.

  When ultraviolet rays or visible rays are used as energy rays, a photopolymerization initiator, a photosensitizer, or the like is included in the curable resin. Examples of the photopolymerization initiator include acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetramethylthiuram monosulfide, thioxanthones, and the like. Examples of the photosensitizer include n-butylamine, triethylamine, and tri-n-butylphosphine.

The thin film layer made of a curable resin may contain compounding agents such as a curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, and a viscosity modifier.
As the organic thin film, a curable resin thin film is preferably used because the aspect ratio of the fine bowl-shaped convex lens portion may be easily controlled.

  The average thickness of the organic thin film is preferably 100 nm to 20 μm. If the thickness is less than 100 nm, it is difficult to form the hook-shaped convex lens portion, and if it is more than 20 μm, it is difficult to control the aspect ratio. When an organic thin film is used, a fine ridge-like convex lens portion having an average distance between the apexes of the ridge-like convex lens portions of 500 nm to 40 μm can be easily obtained.

  The average thickness of the thin film layer is preferably 10% to 100% with respect to the height of the ridge-like convex lens portion on the light control film. If the ratio of the average thickness of the thin film layer is less than 10%, the scratch resistance may be impaired. Conversely, if it is thicker than 100%, warpage may occur when used under severe conditions. There is sex.

  The variation coefficient of the thickness of the thin film layer is preferably 20% or less. When the variation coefficient of the thickness of the thin film layer is larger than 20%, the thickness distribution of the thin film layer becomes large, which may cause warpage. The thickness of the thin film layer can be measured as follows. The light control film is cut perpendicularly in the direction of strong periodicity to obtain an ultrathin section, and the ultrathin section is photographed with a transmission electron microscope. From the photographed image, the thickness of the thin film layer is measured at at least 15 points each of the convex top and the concave bottom, and an average value, standard deviation, and coefficient of variation are calculated from these measured values. In the direction where the periodicity of the light control film is strong, two points with high spatial frequency intensity are extracted from the power spectrum distribution of the spatial frequency obtained by two-dimensional Fourier transform of the scanning electron micrograph image on the surface of the light control film, The direction of the straight line connected by these two points. For example, in a saddle-shaped convex lens in which the direction in which the eyelids extend is aligned in one direction, the direction orthogonal to the direction in which the eyelids extend is a direction with strong periodicity.

  The thin film layer is laminated on the saddle-like convex lens portion and is bent so as to correspond to the shape of the saddle-like convex lens portion. 8 and 9 are schematic views showing a vertical cross section of the light control film used in the present invention. The thin film is bent corresponding to the ridge-like convex lens portion on the surface of the light control film, and the shape of the ridge-like convex lens portion is raised and undulated on the surface of the thin film layer. When the undulation due to the relief becomes small, the light condensing property of the bowl-shaped convex lens portion tends to be weak.

  The preferable light control film used for this invention has a some micro processus | protrusion spaced apart by the average distance between vertices shorter than the average distance between vertices of the said saddle-like convex lens part on the undulating surface of a thin film layer like FIG. In order to allow polarization separation by the microprotrusions, the microprotrusions preferably have an average distance between vertices of 0.2 to 0.8 μm. The height / width ratio of the vertical cross section of the microprotrusions is preferably 1.0 to 4.0.

Further, the microprotrusions are not particularly limited by the shape thereof. For example, a ridge, a cone, a truncated cone, a pyramid, or a truncated pyramid can be used. In the present invention, from the viewpoint of high polarization separation ability, the microprotrusions are preferably striped ridges extending in one direction. In particular, it is preferable that the direction in which the ridges of the ridge-shaped convex lens portion extend and the direction in which the micro ridges extend are substantially parallel (FIG. 7).
A film made of a light-absorbing material may be laminated on the top of the microprotrusions in order to increase the polarization separation ability. The light-absorbing material is preferably a conductive material, and specific examples include metals such as aluminum, indium, magnesium, rhodium and tin. The film forming method is not particularly limited, and examples thereof include a wet plating method and a dry plating method. A wire grid polarizer can be constituted by a film of light-absorbing material on the top of the microprotrusions.

  The light control film used in the present invention preferably has a haze of 70% or more, particularly preferably 75% or more. The light control film used in the present invention preferably has a total light transmittance of 70% or more, particularly preferably 80% or more. By setting the optical characteristics of the light control film in the above range, it can be suitably used as a light control film.

[Manufacturing method of light control film]
The method for producing a light control film used in the present invention comprises a step of forming a thin film on at least one surface of a flat transparent substrate to obtain a laminate, and the laminate in at least one axial direction in the plane. It includes a step of bending and shrinking the thin film.

(Transparent substrate)
The transparent base material used for manufacturing the light control film is not particularly limited as long as it can be contracted in at least one axial direction in the plane after the thin films are laminated. For example, the transparent base material itself may be shrunk by means such as heating, or the direction perpendicular to the stretching direction may be shrunk when uniaxially stretched.

  The average thickness before shrinkage of the transparent substrate is usually 5 μm to 1 mm, preferably 20 to 500 μm from the viewpoint of handling. The transparent substrate is usually made of resin, rubber or elastomer. Examples of the resin, rubber, or elastomer include the same as those exemplified as those constituting the film having the ridge-like convex lens portion. Moreover, the compounding agent may be included like resin which comprises the film which has the said saddle-like convex lens part.

  The transparent substrate is not particularly limited by the production method. The raw fabric of the transparent substrate can be obtained by molding the above-described resin or the like by a known film molding method. Examples of the film forming method include a cast forming method, an extrusion forming method, and an inflation forming method.

  In general, it is preferable that the transparent base material that shrinks itself by means of heating or the like is molecularly oriented in the plane. The state of molecular orientation can be measured by a known method, for example, using an automatic birefringence meter (KOBRA 21ADH).

  A transparent base material that itself shrinks by means of heating or the like can be obtained, for example, by forming the above-described resin or the like on a raw film by a known molding method and stretching the raw film. Moreover, it can be set as the transparent base material which orients a molecule | numerator by applying a magnetic field or an electric field, or rubbing instead of extending | stretching, and shows shrinkage | contraction property. By forming rubber or elastomer on an elastic film by a known molding method and pulling the elastic film in the in-plane direction, it is possible to obtain a transparent base material that exhibits shrinkage utilizing resilience due to elasticity. . Furthermore, a film made of a curable resin can be swollen with a solvent or the like in advance, and a transparent substrate used in the present invention can be obtained by utilizing the shrinkage that occurs when the swollen film dries. Among these, a transparent base material exhibiting shrinkage obtained by stretching a raw film is preferable.

The transparent base material exhibiting shrinkage obtained by stretching the raw film is not particularly limited by the stretching method, and may be stretched by either a uniaxial stretching method or a biaxial stretching method. In the case of biaxial stretching, it usually shrinks in two directions within the film plane.
Examples of the stretching method include uniaxial stretching methods such as a method of uniaxial stretching in the longitudinal direction using the difference in peripheral speed on the roll side, a method of uniaxial stretching in the transverse direction using a tenter stretching machine; At the same time as stretching in the longitudinal direction with a gap between them, and simultaneously stretching in the longitudinal direction using the simultaneous biaxial stretching method that stretches in the transverse direction according to the spread angle of the guide rail and the difference in peripheral speed between the rolls, both ends thereof A biaxial stretching method such as a sequential biaxial stretching method in which a part is clipped and stretched in the lateral direction using a tenter stretching machine; feed force, pulling force or pulling force at different speeds can be applied in the lateral or longitudinal direction. And a method of continuously and obliquely stretching in the direction of an arbitrary angle θ with respect to the width direction of the film using the tenter stretching machine.
Examples of the apparatus used for stretching include a longitudinal uniaxial stretching machine, a tenter stretching machine, a bubble stretching machine, and a roller stretching machine.

  When the shrinkage rate in the main shrinkage direction is significantly increased, elongation may occur in a direction perpendicular to the main shrinkage direction, and the elongation may cause cracks on the thin film surface. From the viewpoint of suppressing the occurrence of cracks during shrinkage, (i) uniaxially stretching in the transverse direction is preferably performed with the longitudinal shrinkage during stretching preferably controlled to 20% or less, more preferably 15% or less (transverse) (Uniaxial stretching method) or (ii) biaxial stretching in the machine direction and transverse direction (biaxial stretching method) is preferred.

The temperature during stretching is preferably between (Tg-30 ° C) and (Tg + 60 ° C), more preferably (Tg-10 ° C), where Tg is the glass transition temperature of the material constituting the transparent substrate. It is selected from temperatures between (Tg + 50 ° C.).
What is necessary is just to select a draw ratio suitably so that it may become a desired aspect ratio of the saddle-like convex lens part according to the tensile characteristic of the transparent base material to be used.

  When it is desired to obtain a high-aspect ratio saddle-shaped convex lens portion, although depending on the film quality and thickness of the thin film, the stretch ratio is generally set high. In order to obtain a ridge-like convex lens portion having a low aspect ratio, the draw ratio is set low. Specifically, the draw ratio in the main drawing direction is usually 1.01 to 30 times, more preferably 1.01 to 10 times, and more preferably 1.05 to 5 times. When the draw ratio in the main draw direction is less than 1.01, the ridge-like convex lens portion does not occur, and when the draw ratio is more than 30 times, the film strength may decrease.

(Thin film)
Next, a thin film is formed on at least one surface of the transparent substrate. The shrinkage rate of the thin film is preferably 20% or less of the shrinkage rate of the transparent base material, and more preferably 10% or less, under the conditions for shrinking the transparent base material. If the shrinkage rate of the thin film is too large, a fine bowl-shaped convex lens part may not be formed.

The average thickness of the thin film before shrinkage is preferably 1 nm to 20 μm. The thickness of the thin film is obtained by photographing a vertical section of the thin film with an electron microscope and obtaining an average value of the thickness from the photograph image.
As described above, the thin film includes an inorganic thin film and an organic thin film.

Examples of the material for the inorganic thin film include the same materials as those exemplified above for the inorganic thin film.
The method for forming the inorganic thin film is not particularly limited, and vapor deposition methods such as vacuum deposition, ion plating, sputtering, CVD (chemical vapor deposition); spin coating method, dipping method, roll coating method, spray method, vapor method, gravure Examples thereof include coating methods such as a coater and a blade coater, coating methods such as a screen printing method and an ink jet method; an electroless plating method and an electrolytic plating method.

Examples of the material for the organic thin film include the same materials as those exemplified for the organic thin film. In addition, the organic thin film may contain the compounding agent mentioned above.
As a method for forming an organic thin film made of a thermoplastic resin, (1) a method of co-extruding a resin constituting a transparent substrate and a resin constituting a thin film; (2) forming a thermoplastic resin into a thin film; (3) The method of apply | coating the solution containing a thermoplastic resin to the surface of a transparent substrate, and drying etc. are mentioned.

  The formation method of the organic thin film which consists of curable resin is not specifically limited. An organic thin film made of a curable resin is obtained, for example, by applying a curable resin composition on a transparent substrate surface and curing it. The curable resin composition may contain a solvent from the viewpoint of improving workability. When forming the curable resin thin film, it is desirable to perform heat treatment at a temperature lower by 5 ° C. or more than the glass transition temperature of the transparent substrate. If a high temperature is applied during thin film formation, the transparent substrate may be annealed and may not shrink as designed.

(Folding induction structure)
In the production of a light control film, before forming a thin film on the surface of the transparent substrate, a structure (curvature inducing structure) for causing the bending of the thin film may be formed on the surface of the transparent substrate. After the thin film is formed on the material surface and before the base material is contracted, a structure (curvature inducing structure) for causing the thin film to bend may be formed on the thin film.

The structure is not particularly limited as long as it causes a bending of the thin film when the base material contracts. For example, the structure is scratched on the surface by rubbing or other methods, and is mounted by an inkjet printer or a printing machine. Examples include irregularities provided by ink stamping, embossing, imprinting, and the like.
It is preferable that the bending induction structure is formed at a constant interval. The interval of the bending induction structure is not directly related to the distance between the vertices of the desired ridge-like convex lens portion, and may be narrower or wider than the distance between the vertices of the desired ridge-like convex lens portion. It is preferable that the distance between the fold-inducing structures is 0.05 to 100 times the desired distance between the apexes of the convex lens portion.

  In the manufacturing method of a light control film, the transparent base material which formed the said thin film on the surface is contracted next, and a thin film is bent. What is necessary is just to select suitably the method of shrinking a transparent base material according to the kind of transparent base material.

  The shrinkage rate of the transparent base material is such that the shrinkage rate ΔL in the main shrinkage direction and the direction orthogonal to the main shrinkage direction so that the thin film or the like does not crack when the thin film is bent by the shrinkage of the transparent base material. It is preferable that the shrinkage ratio ΔM of the above satisfies the formula [3] and the formula [4]. ΔL and ΔM are defined by Equation [1] and Equation [2], respectively.

Formula [1]: ΔL = (L ₀ −L ₁ ) / L ₀ × 100 (L ₀ : length before contraction in the main contraction direction, L ₁ : length after contraction in the main contraction direction)
Formula [2]: ΔM = (M ₀ −M ₁ ) / M ₀ × 100 (M ₀ : length before contraction in the direction orthogonal to the main contraction direction, M ₁ : after contraction in the direction orthogonal to the main contraction direction Length)
Formula [3]: ΔL> 0
Formula [4]: − (ΔL × 0.3) ≦ ΔM ≦ ΔL

When it is desired to increase the anisotropy of the fine ridge-like convex lens portion, that is, when it is desired to make the ridge-like convex lens portion elongated in a stripe shape in the plane, the expressions [3] and [5] are satisfied. preferable.
Formula [5]: − (ΔL × 0.2) ≦ ΔM ≦ (ΔL × 0.2)
Thereby, the anisotropic diffusibility of the light control film obtained can be strengthened.

  As described above, the distance between the apexes of the ridge-like convex lens portions, the aspect ratio, and the like of the light control film can be arbitrarily adjusted simply by changing the contraction conditions.

  The main shrinkage direction is the direction in which the degree of shrinkage (shrinkage rate) is the largest. For example, a transparent substrate obtained by stretching a film made of a thermoplastic resin shrinks by heating. When the film is stretched only in a uniaxial direction, the stretching direction is usually the main shrinking direction. Moreover, when extending | stretching to a biaxial direction, a direction with a large extending | stretching ratio becomes a main shrinking direction among two extended directions normally.

  When a film made of a thermoplastic resin is uniaxially stretched, the film shrinks in a direction orthogonal to the stretching direction. In the transparent substrate using the shrinkage at the time of stretching, the direction perpendicular to the stretching direction is the main shrinking direction. In addition, when the value of the shrinkage rate ΔM in the direction orthogonal to the main shrinkage direction is negative, it indicates that the film has been stretched in the shrinkage treatment. When the film shrinks in the main shrinking direction, if the elongation in the direction perpendicular to the main shrinking direction becomes too large, the thin film tends to crack. For this reason, the shrinkage rate in the direction orthogonal to the main shrinkage direction is preferably 1% to 90%, and more preferably 1% to 50%.

The radius of curvature of the apex of the saddle-shaped convex lens portion changes depending on the degree of curvature. The degree of bending varies depending on the shrinkage rate of the thin film and the film substrate, the thickness of the thin film and the film substrate, and the degree of adhesion between the thin film and the film substrate.
No matter how precisely and uniformly a film substrate or thin film having a predetermined thickness is produced, the shrinkage rate of the thin film and the film substrate, the thickness of the thin film and the film substrate, and the adhesion between the thin film and the film substrate Produces a distribution with statistical probability. By the distribution based on the statistical probability such as the shrinkage rate and the thickness, the distribution is generated with the statistical probability in the degree of folding. The manufacturing method of a light control film uses the distribution which arises with this statistical probability, and makes the curvature radius of the vertex of a saddle-like convex lens part different from adjacent saddle-like convex lens parts.
The radius of curvature of the apex of the saddle-like convex lens portion greatly depends on the material composition of the base film and the thin film, the material configuration such as the thickness, and the manufacturing conditions such as film formation of the thin film layer, stretching and contraction of the base film. . For example, in order to reduce σr / Xr, it is only necessary to reduce fluctuations in the material configuration and manufacturing conditions (for example, unevenness in thickness and unevenness in stretching), and conversely, in order to increase σr / Xr, the fluctuations described above. Should be increased. That is, Xr and σr / Xr can be controlled by adjusting the material configuration and manufacturing conditions.

  The distance and variation between the ridge-like convex lens portions largely depend on the material conditions such as the material and thickness of the thin film, and the production conditions such as stretching and shrinking of the base film. For example, in order to reduce Xp, an inorganic thin film may be used or the thickness of the thin film may be reduced. Conversely, in order to increase Xp, an organic thin film may be used or the thickness of the thin film may be increased. good. In order to reduce σp / Xp, the uniaxiality of the shrinkage of the base film is increased (for example, the difference in stretch ratio is increased by biaxial stretching with different stretch ratios), and the bending induction structure is used. Conversely, in order to increase σp / Xp, the uniaxiality of the shrinkage of the base film may be lowered (for example, the difference in the draw ratio is reduced by biaxial stretching with different draw ratios). That is, Xp and σp / Xp can be controlled by adjusting the material configuration and manufacturing conditions.

[Organic EL device]
The organic EL element used in the present invention is not particularly limited by the structure of the organic EL element as long as it has a lower electrode layer, a light emitting material layer, and an upper electrode layer as minimum constituent units. A typical organic EL element is formed by laminating a substrate, a lower electrode layer, a light emitting material layer, an upper electrode layer, and a sealing layer in this order. The substrate and the sealing layer are portions for supporting and protecting the lower electrode layer, the light emitting material layer, and the upper electrode layer.

  As a substrate used for an organic EL element, the light transmittance in the visible region of 400 to 700 nm is 50% or more, is smooth, and does not change in quality when the electrode or each layer of the element is formed. preferable. Examples of such a substrate include a glass plate and a polymer film. The average thickness of the substrate is usually 30 μm to 3 mm, preferably 50 to 300 μm.

  The material which comprises the upper electrode layer used for an organic EL element is not restrict | limited in particular, For example, a conductive metal oxide, a translucent metal, or its laminated body is mentioned. Specifically, indium oxide, zinc oxide, tin oxide, and composites thereof, such as indium tin oxide (ITO), transparent conductive materials such as indium zinc oxide, etc. (NESA etc.), gold, Platinum, silver, copper and the like are used, and among them, ITO, indium / zinc / oxide, and tin oxide are preferable.

The average thickness of the upper electrode layer can be appropriately selected in consideration of light transmittance and electrical conductivity, but is usually 10 nm to 10 μm, preferably 100 to 500 nm.
In the light emitting device of the present invention, it is convenient that the upper electrode layer is transparent or translucent because the emission efficiency of light emission is good. Examples of the method for forming the upper electrode layer include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded.

There is no restriction | limiting in particular in the material which comprises the light emitting material layer used for an organic EL element, A well-known thing can be used as a light emitting material in an organic EL element. Examples of such luminescent materials include fluorescent brighteners such as benzothiazole, benzimidazole, and benzoxazole, metal chelated oxinoid compounds, styrylbenzene compounds, distyrylpyrazine derivatives, and aromatic dimethylidine compounds. It is done.
The average thickness of the light-emitting material layer varies depending on the material used, and may be selected so that the drive voltage and the light emission efficiency are appropriate. Usually, the thickness is 1 nm to 1 μm, preferably 2 nm to 500 nm. is there.
In the light emitting device of the present invention, two or more kinds of light emitting materials may be mixed and used in the light emitting material layer, or two or more light emitting material layers may be laminated. Examples of the method for forming the light emitting material layer include a vacuum deposition method and a casting method.

As a material constituting the lower electrode layer used in the organic EL element, a material having a small work function is preferable. In order to reflect emitted light from the light emitting material layer toward the lower electrode layer and to direct toward the sealing layer, a mirror body is used. More preferably it is. Specifically, metals such as lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, And an alloy of two or more metals selected from these, or one or more metals selected from these, and selected from gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, and tin An alloy with one or more metals, graphite, a graphite intercalation compound, or the like is used. Specific examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, and calcium-aluminum alloy. . The lower electrode layer may have a laminated structure of two or more layers. Examples of the method for forming the lower electrode layer include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method.
The average thickness of the lower electrode layer can be appropriately selected in consideration of electric conductivity and durability, but is usually 10 nm to 10 μm, preferably 100 to 500 nm.

The sealing layer is preferably formed of a film having excellent water vapor barrier properties. The material constituting the sealing layer is selected from materials having a low water vapor transmission rate. For example, cycloolefin polymer; fluorine resin such as perfluoroolefin, laminated structure of resin film and silicon nitride oxide film; Si ₃ N ₄ or diamond-like carbon film; target resin such as cycloolefin polymer and perfluoroolefin CVD film used as: an organic film using a fluorine compound or alicyclic structure-containing polymer and a metal simple substance or a metal compound as a raw material, an inorganic film using a metal simple substance or a metal compound as a raw material, and a transparent resin substrate Laminates; and the like. The water vapor transmission rate of the sealing layer is preferably 0.005 g / m ² · Day or less (25 ° C., 75% RH).

The organic EL element used in the present invention may have other layers in addition to the substrate, the lower electrode layer, the light emitting material layer, the upper electrode layer, and the sealing layer.
Examples of the other layers include a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.
The hole injection layer is a layer provided adjacent to the anode and refers to a layer having a function of improving hole injection efficiency from the anode. The average thickness of the hole injection layer is usually 1 nm to 100 nm, preferably 2 nm to 50 nm.

The hole transport layer refers to a layer having a function of transporting holes. The thickness of the hole transport layer differs depending on the material used and may be selected so that the drive voltage and the light emission efficiency are appropriate, but at least a thickness that does not cause pinholes is required. If the thickness is too thick, the driving voltage of the element increases, which is not preferable. Therefore, the average thickness of the hole transport layer is usually 1 nm to 1 μm, preferably 2 nm to 500 nm.
Examples of materials used for the hole injection layer and the hole transport layer include those conventionally known as hole transport compounds in organic EL devices.

The electron transport layer refers to a layer having a function of transporting electrons.
The thickness of the electron transport layer varies depending on the material used and may be selected so that the driving voltage and the light emission efficiency are appropriate values, but at least a thickness that does not cause pinholes is required. If the thickness is too thick, the drive voltage of the element becomes high, which is not preferable. Therefore, the average thickness of the electron transport layer is usually 1 nm to 1 μm, preferably 2 nm to 500 nm.
The electron injection layer is a layer provided adjacent to the cathode and has a function of improving the electron injection efficiency from the cathode and has an effect of lowering the driving voltage of the element.
The average thickness of the electron injection layer is usually 1 nm to 100 nm, preferably 2 nm to 50 nm.
Examples of materials used for the electron transport layer and the electron injection layer include those conventionally known as electron transport compounds in organic EL devices.
Examples of methods for forming these other layers include spin coating, casting, and vacuum deposition.

  The light emitting device of the present invention comprises the light control film on the light output side of the organic EL device. When the organic EL element is a bottom emission method, a light control film is provided on the transparent substrate side. When the organic EL element is a top emission system, a light control film is provided on the sealing layer side. As described above, since the organic EL element has the lower electrode layer, the light emitting material layer, and the upper electrode layer as the minimum structural units, the light control film can be used in place of the substrate or the sealing layer described above. . By using the light control film as a substrate or a sealing layer, the layer structure of the organic EL element can be simplified and the film can be made thinner. When the light control film is used for the substrate or the sealing layer, the lower electrode layer or the upper electrode layer may be laminated on a flat surface where the ridge-like convex lens portion is not provided, or the ridge-like convex lens portion. The lower electrode layer or the upper electrode layer may be laminated on the uneven surface on the side.

  The light-emitting element of the present invention has a light transmittance in the wavelength range of 400 nm to 800 nm, preferably 80% or more, particularly preferably 90% or more, when no light is emitted. Even when the light-emitting element of the present invention is provided on a windshield of an automobile or the like, the light transmittance at the time of non-light emission is high, so that the front visibility is not hindered.

  The light-emitting element of the present invention can be used as a planar light source, a segment display device, a dot matrix display device, a backlight of a liquid crystal display device, a planar light source, and the like.

  In order to obtain a planar light source including the light emitting element of the present invention, a planar anode (upper electrode layer) and a cathode (lower electrode layer) may be disposed. In addition, in order to obtain pattern-like light emission, a method of installing a mask provided with a pattern-like window on the surface of the planar light-emitting element, an organic material layer of a non-light-emitting portion is formed extremely thick and substantially non- There are a method of emitting light and a method of forming either one of the anode or the cathode or both electrodes in a pattern. By forming a pattern by any of these methods and arranging several electrodes so that they can be turned on / off independently, a segment type display element capable of displaying numbers, letters, simple symbols, and the like can be obtained.

  Further, in order to obtain a dot matrix element, both the anode and the cathode may be formed in a stripe shape and arranged so as to be orthogonal to each other. Partial color display and multi-color display are possible by a method of separately coating a plurality of types of polymers having different emission colors or a method using a color filter or a fluorescence conversion filter. The dot matrix element may be either passive drive or active drive combined with a thin film transistor using amorphous silicon or low-temperature polysilicon. These display elements can be used as display devices for computers, televisions, mobile terminals, mobile phones, car navigation systems, video camera viewfinders, and the like.

  The planar light emitting element is self-luminous and thin, and can be suitably used as a planar light source for a backlight of a liquid crystal display device or a planar illumination light source. If a flexible substrate is used, it can be used as a curved light source or display device.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Size of ridge-like convex lens on the light control film surface)
The structure formed on the film surface was photographed with a field emission scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.). The scanning electron microscope image was subjected to two-dimensional fast Fourier transform using image analysis software (Soft Imaging System, AnySIS) to determine the spatial frequency power spectrum distribution, and the direction showing strong periodicity was read. The film was cut in this direction using an ultramicrotome, and the cross section was photographed with a scanning electron microscope (manufactured by Hitachi, Ltd., S-4700).
This cross-sectional photography was performed at three points at least 10 cm apart in the film width direction and the flow direction. From the scanning electron micrograph images at the three locations, the distance between the apexes of the saddle-like convex lens portions was measured at 30 points, and the average value and the standard deviation were obtained. As for the radius of curvature, the apex portion of the saddle-like convex lens portion was fitted by image processing, the radius of curvature of all 30 vertices was measured, and the average value and the standard deviation were obtained. In addition, the length and width of the ridges were similarly measured at 30 points to obtain an average value.

(Total light transmittance, haze)
Using a turbidimeter (NDH2000 model, manufactured by Nippon Denshoku), the measurement was performed according to JIS-K-7105.

Production Example 1 (Uniaxially stretched film with a draw ratio of 1.2)
Pellets of alicyclic olefin polymer (ZEONOR 1420, glass transition temperature 136 ° C., manufactured by Nippon Zeon Co., Ltd.) were dried at 100 ° C. for 4 hours in a hot air dryer in which nitrogen was circulated. The pellets are supplied to a T-die film melt extrusion molding machine equipped with a 50 mmφ screw and extruded at a molten resin temperature of 260 ° C. to form a film having a width of 650 mm and a thickness of 188 μm. Trimming was performed to obtain a base film having a width of 600 mm.

  The both ends of a base film having a width of 600 mm were gripped by clips, introduced into a tenter stretching machine, and stretched laterally and uniaxially at a temperature of 150 ° C. so as to be 1.2 times in the film width direction and 1.0 times in the film flow direction. . The film coming out of the tenter stretching machine was removed from the clip, and both ends were continuously trimmed to obtain a stretched film (1) having a width of 700 mm.

Production Example 2 (Uniaxially stretched film with a draw ratio of 2.0)
In Production Example 1, a stretched film (2) having a width of 1000 mm was obtained in the same manner as in Production Example 1, except that the stretching ratio was changed to 2.0 times in the film width direction and 1.0 times in the film flow direction. It was.

Production Example 3 (Biaxially stretched film (stretch ratio: 1.6 times width, 1.3 times length))
The base film having a width of 600 mm obtained in Production Example 1 was stretched 1.3 times in the longitudinal direction at a temperature of 145 ° C. using a longitudinal uniaxial stretching apparatus. Subsequently, this longitudinally stretched film was sent to a tenter stretching (lateral uniaxial stretching) apparatus, and stretched 1.6 times in the film width direction and 1.0 times in the film flow direction at 150 ° C. to obtain a stretched film (3). .

Production Example 4 (UV curable resin)
Mixing 90.0 parts by mass of ditrimethylolpropane tetraacrylate (NK ester AD-TMP, manufactured by Shin-Nakamura Chemical Co., Ltd.), 10.0 parts by mass of photoinitiator (Irgacure 907, manufactured by Ciba Geigy), and 900.0 parts by mass of butyl acetate The mixture was stirred until uniform and then filtered through a 1 μm filter to prepare an ultraviolet curable resin solution.

Production Example 5 (Organic EL device)
An ITO ceramic target (In ₂ O ₃ : SnO ₂ = 90% by weight: 10% by weight) is formed on one side of a glass substrate having a thickness of 1 mm by sputtering to form an ITO film having a thickness of 100 nm and transparent. An electrode (anode) was formed. ITO was etched using a photoresist so that the light emitting area was 20 mm × 20 mm, a pattern was formed, ultrasonic cleaning was performed, and ozone cleaning was performed using a low-pressure ultraviolet lamp. Next, organic layers were sequentially formed on the ITO surface by vacuum deposition as follows.

First, CuPc represented by the formula (1) as a hole injection layer was formed to a thickness of 15 nm at a deposition rate of 0.3 nm / s. Next, TPD represented by Formula (2) as a hole transporting blue light emitting layer was formed to a thickness of 40 nm at a deposition rate of 0.3 nm / s. Next, TAZ represented by the formula (3) was formed as a hole blocking layer at a deposition rate of 0.3 nm / s to a thickness of 15 nm. Finally, Alq represented by the formula (4) as an electron transport layer was formed to a thickness of 90 nm at a deposition rate of 0.3 nm / s. Thereafter, Mg is co-deposited at a deposition rate of 1 nm / s and Ag is 0.1 nm / s to form MgAg with a thickness of 100 nm. From the viewpoint of preventing MgAg oxidation, 50 nm of Ag is formed on MgAg. Thus, a reflective electrode (cathode) was obtained. Take out from the vacuum evaporation system, drop UV curable epoxy resin on the cathode electrode side, cover it with 1mm thick glass, and irradiate with UV when the epoxy resin spreads sufficiently (integrated light quantity 150mJ / cm ² ) The epoxy resin was cured to produce an organic EL element.

Example 1
The stretched film (1) obtained in Production Example 1 was subjected to corona discharge treatment for surface modification. The UV curable resin solution prepared in Production Example 4 was applied to the film using a gravure coater so that the dry film thickness was 0.4 μm, dried at 80 ° C. for 5 minutes, and then ultrahigh pressure mercury. A laminated film was obtained by irradiating with an ultraviolet ray using a lamp (integrated light quantity: 400 mJ / cm ² ) and curing the coating film.
Next, the laminated film was passed through a dryer in which hot air at 140 ° C. was circulated, and the laminated film was contracted to obtain a light control film 1.

  As shown in FIGS. 2 and 3, a plurality of hook-like convex lens portions are formed on the surface of the light control film 1, and a thin film formed of an ultraviolet curable resin is bent so as to correspond to the shape of the hook-like convex lens portions. Thus, the surface of the thin film layer was raised and undulated on the surface of the thin film layer. The ridge-like convex lens portion had a long longitudinal direction of the ridge substantially aligned in one direction and exhibited strong periodicity in the short direction of the ridge. Further, the radii of curvature at the vertices of at least one pair of adjacent saddle-shaped convex lens portions were different from each other. The ratio of the length and width of the ridges was 5 or more.

The average value (Xr) of the radius of curvature of the apex of the saddle-like convex lens portion was 0.25 μm, the standard deviation (σr) was 0.028 μm, and σr / Xr was 0.112.
The average value (Xp) of the interval between the saddle-shaped convex lens portions was 1.8 μm, the standard deviation (σp) was 0.66 μm, and σp / Xp was 0.367.
The average aspect ratio of the saddle-like convex lens portion was 0.5. The light control film 1 had a total light transmittance of 88% and a haze of 80%.

The flat surface side of the light control film 1 where the ridge-like convex lens portion is not formed is subjected to corona discharge treatment, and then the acrylic adhesive is dissolved in butyl acetate so that the solid content concentration is 20% on the treated surface. The solution was applied using an applicator, dried in a dryer at 50 ° C. for 5 minutes, and an adhesive layer having a thickness of 5 μm was laminated.
As shown in FIG. 10, the light-emitting element 1 was produced by laminating the light control film 1 on which the adhesive layer was laminated on the glass substrate side of the organic EL element.
A voltage of 5 V was applied between the anode layer and the cathode layer of the light-emitting element 1 to emit light. The light output from the light emitting element 1 was measured with a luminance meter (Prometric). The light extraction efficiency was expressed as a magnification relative to Comparative Example 1 described later. The light-emitting element 1 had an emission luminance of 240 cd / m ² and a light extraction efficiency of 2.4 times.
Next, steel wool # 0000 was brought into contact with the light control film 1 side of the light-emitting element 1 and reciprocated 30 times in a state where a load of 0.02 MPa was applied. The light extraction efficiency was maintained at 2.4 times as measured by a luminance meter manufactured by Prometric. Further, the light-emitting element 1 was left in an environment of 60 ° C. × 85% RH for 500 hours, but no deformation such as warping was observed.

Example 2
Example 1 except that the stretched film (1) obtained in Production Example 1 was replaced with the stretched film (2) obtained in Production Example 2 and an ultraviolet curable resin solution was applied so that the dry film thickness was 4.0 μm. The light control film 2 was obtained by the method similar to.
As shown in FIG. 4, a plurality of ridge-like convex lens portions are formed on the surface of the light control film 2, and a thin film formed of an ultraviolet curable resin is bent and laminated so as to correspond to the shape of the ridge-like convex lens portion. On the thin film layer side surface, the shape of the ridge-like convex lens portion was raised and undulated. The ridge-like convex lens portion had a long longitudinal direction of the ridge substantially aligned in one direction and exhibited strong periodicity in the short direction of the ridge. Further, the radii of curvature at the vertices of at least one pair of adjacent saddle-shaped convex lens portions were different from each other. The ratio of the length and width of the ridges was 5 or more. When the cross-sectional shape of the film was measured, the average value (Xp) of the interval between the saddle-shaped convex lens portions was 38.0 μm, the standard deviation (σp) was 3.90 μm, and σp / Xp was 0.103. The light control film 2 had a total light transmittance of 79% and a haze of 77%.

Next, in the same manner as in Example 1, the light control film 2 was laminated on the organic EL device to produce the light emitting device 2. The light-emitting element 2 had an emission luminance of 230 cd / m ² and a light extraction efficiency of 2.3 times. Further, in the same manner as in Example 1, a steel wool durability test and a high temperature and high humidity durability test were conducted. The light-emitting element 2 did not show any reduction in light extraction efficiency and deformation such as warpage in each durability test.

Example 3
Example 1 except that the stretched film (1) obtained in Production Example 1 was replaced with the stretched film (3) obtained in Production Example 3 and an ultraviolet curable resin solution was applied so that the dry film thickness was 1.7 μm. The light control film 3 was obtained by the method similar to.
As shown in FIG. 5, a plurality of ridge-like convex lens portions are formed on the surface of the light control film 3, and a thin film formed of an ultraviolet curable resin is bent and laminated so as to correspond to the shape of the ridge-like convex lens portions. As a result, the surface of the thin film layer was raised and undulated with the shape of the ridge-like convex lens portion. As shown in FIG. 5, the saddle-shaped convex lens has a complicated bend and has a small difference between a direction with a strong periodicity and a weak direction. Further, the radii of curvature at the vertices of at least one pair of adjacent saddle-shaped convex lens portions were different from each other. The ratio of the heel length to the width was 5 or more.
The average value (Xp) of the interval between the saddle-shaped convex lens portions was 5.4 μm, the standard deviation (σp) was 4.48 μm, and σp / Xp was 0.830. The average aspect ratio of the saddle-like convex lens portion was 3.7. The light control film 3 had a total light transmittance of 76% and a haze of 88%.

Next, in the same manner as in Example 1, the light control film 3 was laminated on the organic EL element to produce the light emitting element 3. The light-emitting element 3 had a light emission luminance of 260 cd / m ² and a light extraction efficiency of 2.6 times. Further, in the same manner as in Example 1, a steel wool durability test and a high temperature and high humidity durability test were conducted. The light emitting element 3 did not show any decrease in light extraction efficiency or deformation such as warpage in each durability test.

Example 4
An 8 mm x 8 mm x 60 mm stainless steel shank brazed 0.2 mm x 1 mm x 1 mm cuboidal single crystal diamond has an entire surface of 0.2 mm x 1 mm with a focused ion beam processing device SMI3050 (Seiko Instruments Inc. And a focused ion beam machining with an argon ion beam was used to produce a cutting tool in which ridges having a width of 100 nm and a height of 100 nm and a rectangular cross section having a width of 100 nm were formed at a pitch of 200 nm.

  The surface of a stainless steel SUS430 plate having dimensions of 50 mm × 50 mm and a thickness of 10 mm is subjected to nickel-phosphorus electroless plating with a thickness of 100 μm, and a precision micromachining machine (manufactured by Nagase Integrex, ultra-precision micromachining machine NIC200) Using the cutting tool, the nickel-phosphorus electroless plating surface was cut to obtain a metal mold having a groove having a rectangular cross section with a pitch of 200 nm, a depth of 100 nm, and a width of 100 nm. Note that. Cutting tool fabrication by focused ion beam machining and cutting of nickel-phosphorus electroless plating surface are at a temperature of 20.0 ± 0.2 ° C, and vibration displacement of 0.5Hz or more is possible by vibration control system (made by Showa Science). The measurement was performed in a constant temperature and low vibration chamber controlled to 10 μm or less.

The surface of the stretched film (1) was modified by corona discharge. The UV curable resin solution obtained in Production Example 4 was applied to the modified surface of the stretched film (1) so as to have a dry film thickness of 1.0 μm using a gravure coater, and dried at 80 ° C. for 5 minutes. The metal mold was pressed and laminated on the coating film of the stretched film (1) so that the longitudinal direction of the groove of the metal mold and the shrinking direction of the stretched film (1) were orthogonal to each other. Subsequently, ultraviolet rays were irradiated with an ultrahigh pressure mercury lamp at an integrated light quantity of 400 mJ / cm ² to cure the ultraviolet curable resin, the groove pattern of the metal mold was transferred to the cured resin layer, and peeled off from the metal mold to obtain a transfer film.

  The obtained film was cut into a predetermined size, a TEM observation cross section was prepared using a micro sampling device attached to the focused ion beam processing observation device FB-2100 (manufactured by Hitachi, Ltd.), and a transmission electron microscope H7500 ( The cross section of the film was observed with Hitachi, Ltd. The pattern shape of the metal mold was transferred to the cured resin layer, and ridges (micro protrusions) having a cross section of a width of 100 nm and a height of 100 nm were formed in parallel at a pitch of 200 nm.

  The film was put into a dryer in which hot air having a temperature of 140 ° C. was circulated, and the film was contracted to obtain a light control film 4. As shown in FIG. 6, the surface of the stretched film (1) on the side of the cured resin layer is formed with wrinkles extending in stripes, and the cured resin layer laminated so as to correspond to the wrinkles is bent. As a result, undulations were formed on the surface of the cured resin layer due to the ridge-shaped protrusion of the base material. The average value (Xp) of the distances between vertices of ridges (undulations) was 10.8 μm, the standard deviation (σp) was 3.71 μm, and σp / Xp was 0.344. The heel length / width ratio was 5 or more.

As shown in FIG. 7, on the surface of the cured resin layer, a pattern (micro protrusions) transferred before shrinkage is formed in the same shape (width 100 nm, height 100 nm, pitch 200 nm) in parallel after shrinkage. ). The longitudinal direction of the ridges having a rectangular cross section is substantially parallel to the longitudinal direction of the ridges extending in a stripe shape, and is substantially orthogonal to the inclined surface of the ridges. The light control film 4 had a total light transmittance of 74% and a haze of 75%.
Next, in the same manner as in Example 1, the light control film 4 was laminated on the organic EL element to produce the light emitting element 4. The light-emitting element 4 had a light emission luminance of 300 cd / m ² and a light extraction efficiency of 3.0 times. Further, in the same manner as in Example 1, a steel wool durability test and a high temperature and high humidity durability test were conducted. In the light emitting element 4, the light extraction efficiency was reduced by about 2.8 times in the steel wool durability test, which was about 7%, but no deformation such as warping was observed in the high temperature and high humidity durability test.

Comparative Example 1
The base film produced in Production Example 1 was laminated on the organic EL element in the same manner as in Example 1 to produce Light-Emitting Element 0. The light-emitting element 0 had a light emission luminance of 100 cd / m ² . In this example, evaluation was performed with the light emitting element 0 as a reference.

Comparative Example 2
Using a precision micromachining machine (manufactured by Nagase Integrex, ultra-precision micromachining machine NIC200), on the surface of a plate made of an alicyclic olefin polymer (ZEONOR1420, glass transition temperature 136 ° C., Nippon Zeon) with a thickness of 1 mm, Plural square pyramidal prisms having a base of 50 μm and a height of 25 μm with a vertex at the top were dug to obtain a prism sheet 5. In the prism pattern, the top of the convex portion is pointed, and the ratio of the length and width of the convex portion is 1.
Next, in the same manner as in Example 1, the prism sheet 5 was laminated on an organic EL element to produce a light emitting element 5. The light-emitting element 5 had a light emission luminance of 300 cd / m ² and a light extraction efficiency of 3.0 times. Further, in the same manner as in Example 1, a steel wool durability test and a high temperature and high humidity durability test were conducted. The light-emitting element 5 did not show deformation such as warpage in the high-temperature and high-humidity durability test, but the light extraction efficiency decreased by about 33.3% by 2.0 times in the steel wool durability test.

Comparative Example 3
Using a precision micromachining machine (manufactured by Nagase Integrex, ultra-precision micromachining machine NIC200), on the surface of a plate made of an alicyclic olefin polymer (ZEONOR1420, glass transition temperature 136 ° C., Nippon Zeon) with a thickness of 1 mm, A plurality of triangular prisms having a vertex of 50 μm in width, a height of 25 μm, and a pitch of 50 μm were dug to obtain a transfer sheet.
The ultraviolet curable resin solution produced in Production Example 4 was applied to the prism pattern surface of the transfer sheet and dried at 80 ° C. for 5 minutes. A polyethylene terephthalate (PET) film having a thickness of 100 μm is laminated on the coated surface, and an ultraviolet ray is irradiated using an ultra-high pressure mercury lamp (accumulated light amount: 400 mJ / cm ² ) to cure the ultraviolet curable resin. Glued. The transfer sheet was peeled off, and a PET prism sheet 6 having a triangular prism shape with a width of 50 μm, a height of 25 μm, and a pitch of 50 μm with an apex on the upper side was produced. The prism pattern is formed on a flat PET film, and the apex of the convex portion of the prism is sharp.

Next, in the same manner as in Example 1, the prism sheet 6 was laminated on an organic EL element to produce a light emitting element 6. The light-emitting element 6 had a light emission luminance of 245 cd / m ² and a light extraction efficiency of 2.45 times. Further, in the same manner as in Example 1, a steel wool durability test and a high temperature and high humidity durability test were conducted. In the light emitting element 6, in the steel wool durability test, the light extraction efficiency was reduced by 1.9 times, or about 22.4%. In the high-temperature and high-humidity durability test, deformation such as warping was noticeable.

Claims (6)

A light control film having at least one surface having a plurality of ridge-like convex lens portions in which the ratio (length / width) of the ridges is 5 or more and the top of the ridge forms a convex curved surface The
A light emitting device provided on the light output side of the organic electroluminescence device. In the light control film, the average value Xp of the interval between the ridge-like convex lens portions is 0.2 to 40 μm, and the standard deviation σp of the interval between the ridge-like convex lens portions is σp / Xp = 0.1 with respect to Xp. The light emitting element of Claim 1 which is -0.9.   3. The light emitting device according to claim 1, wherein the light control film has a total light transmittance of 70% or more and a haze of 70% or more.   The light control film further includes a thin film layer that is laminated on the bowl-shaped convex lens section and is bent so as to correspond to the shape of the bowl-shaped convex lens section, and the surface of the thin film layer is the bowl-shaped convex lens section. The light emitting device according to any one of claims 1 to 3, wherein the light emitting device is undulated by a relief of the shape.   5. The light control film according to claim 1, wherein the light control film has a plurality of micro protrusions spaced apart by an average distance between vertices shorter than an average distance between vertices of the hook-shaped convex lens portion on the undulating surface of the thin film layer. Light emitting element.   The light-emitting element according to claim 1, wherein the organic electroluminescence element is formed by sequentially laminating a substrate, a lower electrode layer, a light-emitting material layer, an upper electrode layer, and a sealing layer.

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