Composition for anisotropic optical film and anisotropic optical film

Abstract

A composition for an anisotropic optical film is provided, which can be manufactured to obtain good diffusion properties and excellent viewing angle expansion when used in a display device. A composition for an anisotropic optical film characterized by comprising: (A) a (meth)acrylic acid ester having a refractive index nA of 1.50 to 1.65 and having one or more aromatic rings and (meth)acryloyl groups; (C) a polymerization initiator; and (D) a polymerization inhibitor having a structure in which a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound, wherein the content of (C) is 0.1 to 20 parts by weight per 100 parts by weight of the non-volatile component of the composition, and the content of (D) is 0.001 to 1 part by weight per 100 parts by weight of the non-volatile component of the composition.

Description

Technology Field

[0001] The present invention relates to a composition for an anisotropic optical film and an anisotropic optical film manufactured using the composition for an anisotropic optical film. Background Technology

[0002] Various display devices, such as liquid crystal displays (LCDs) and organic electroluminescent devices (organic ELs), may have an anisotropic light diffusion layer applied for purposes such as expanding the viewing angle.

[0003] As such a light diffusion layer, Patent Document 1 discloses a light control plate that can be obtained by curing a raw material composition having a high refractive index material and a low refractive index material by irradiating it with ultraviolet light.

[0004] In addition, Patent Document 2, which is a further application, discloses a light-diffusing film formed by curing a raw material composition containing a (meth)acrylic acid ester compound having an aromatic backbone as a high-refractive-index material, and a urethane (meth)acrylate compound containing a specific polyol compound and a polyisocyanate compound as a low-refractive-index material. Prior art literature

[0005] Patent Document 1: Japanese Patent No. 3211381 Patent Document 2: Japanese Patent No. 6414883 The problem to be solved

[0006] The light diffusion layer prepared from the raw material composition according to the above patent documents 1 and 2 can widen the diffusion width at which light is primarily scattered to some extent, but it cannot obtain a sufficiently wide diffusion width, and the widening of the viewing angle when used in a display device is also insufficient.

[0007] The present invention aims to provide a composition for an anisotropic optical film that can be manufactured to obtain good diffusion properties and excellent viewing angle expansion when used in a display device. means of solving the problem

[0008] The inventors of the present invention have diligently conducted research and discovered that the above problem can be solved by using a specific (meth)acrylate as a base resin component and also by combining a specific component, thereby completing the present invention.

[0009] The present invention is,

[0010] (A) As a component, a (meth)acrylic acid ester having a refractive index nA of 1.50 to 1.65 and having one or more aromatic rings and (meth)acryloyl groups, and

[0011] (C) As a component, a polymerization initiator, and,

[0012] (D) As a component, a polymerization inhibitor having a structure in which a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound.

[0013] A composition for an anisotropic optical film comprising a constituent component including,

[0014] In the above components,

[0015] For every 100 parts by weight of the non-volatile component of the above composition, the content of the (C) component is 0.1 to 20 parts by weight, and

[0016] For every 100 parts by weight of the non-volatile component of the above composition, the content of the (D) component is 0.001 parts by weight to 1 part by weight

[0017] A composition for an anisotropic optical film characterized by being.

[0018] The above-mentioned components may additionally include a component (B) having a refractive index nB of 1.35 to 1.54, and a component having a refractive index nB smaller than the refractive index nA.

[0019] The above component (B) may be a copolymer having a content of (meth)acrylic acid ester in the constituent monomers of 10% to 80% by weight, and

[0020] In the above components,

[0021] The content of the above (B) component may be 10 to 400 parts by weight with respect to 100 parts by weight of the above (A) component.

[0022] The above (D) component may be one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6).

[0023]

[0024] (In formulas (D1) to (D6), R1 to R5 are each independently a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 alkoxy group or an alkyl group.)

[0025] The above component (B) may be a thermoplastic polymer having a weight average molecular weight of 1,000 to 500,000 and a glass transition temperature of -40°C or higher.

[0026] The above component (B) may be a urethane (meth)acrylic acid ester composed of a cyclic aliphatic compound having two isocyanate groups, a polyalkylene glycol, and a hydroxyalkyl (meth)acrylic acid ester, having a weight average molecular weight of 3,000 to 20,000.

[0027] In addition, the present invention,

[0028] A cured product of the above-mentioned composition for an anisotropic optical film, and an anisotropic optical film in which linear transmittance, which is the ratio of the amount of light transmitted in the straight direction of the incident light to the amount of incident light, changes according to the angle of incidence of light.

[0029] The above anisotropic optical film has a matrix region and a plurality of columnar regions with a refractive index different from that of the matrix region, and

[0030] The above-mentioned columnar region is configured to be oriented and also serially arranged from one surface of the anisotropic optical film to the other surface, and

[0031] The anisotropic optical film may also have an aspect ratio of average major axis / average minor axis of the columnar region on the surface of the anisotropic optical film of 1 to 50.

[0032] The above aspect ratio may be 2 to 20.

[0033] The thickness of the above anisotropic optical film may be 10 μm to 200 μm. Effects of the invention

[0034] According to the present invention, it is possible to provide a composition for an anisotropic optical film capable of producing an anisotropic optical film that can obtain good diffusion properties and has an excellent widening of the viewing angle when used in a display device. Brief explanation of the drawing

[0035] [Fig. 1] This is a schematic diagram showing an example of an anisotropic optical film. [Fig. 2] This is a top view showing the surface structure of an anisotropic optical film. [Fig. 3] This is a three-dimensional polar coordinate representation to explain the scattering center axis in an anisotropic optical film. [Fig. 4] This is a schematic diagram showing the method for measuring the diffusion performance of an anisotropic optical film. [Fig. 5] This is a schematic diagram showing a method for manufacturing an anisotropic optical film according to the present invention, including optional processes 1-3. [Fig. 6] A graph of an optical profile showing the diffusion width of the anisotropic optical films of Example 1 and Comparative Example 1. Specific details for implementing the invention

[0036] The composition for an anisotropic optical film according to the present invention, and an anisotropic optical film obtained by curing the composition for an anisotropic optical film (anisotropic optical film which is a cured product of the composition for anisotropic optical film), etc., will be described. Additionally, the term "composition for anisotropic optical film" refers to a composition used to manufacture an anisotropic optical film.

[0037] In the following description, where upper and lower limits are listed separately, all combinations of upper and lower limits shall be deemed to be described in this specification.

[0038] In the present invention, the refractive index of each component refers to that measured by a method in accordance with JIS K0062.

[0039] <<<<Composition for Anisotropic Optical Films>>>>

[0040] <<<Ingredients>>>

[0041] A composition for an anisotropic optical film comprises components including (A), which is a (meth)acrylic acid ester; (C), which is a polymerization initiator; and (D), which is a polymerization inhibitor. Additionally, it is preferable that the composition for an anisotropic optical film includes (B), which is a low-refractive index material. Here, trace reactions between the components of the composition for an anisotropic optical film during storage, etc., are also within the scope of the present invention.

[0042] <<(A) Ingredient: (Meta)Acrylic Acid Ester>>

[0043] (A) The component needs to be a (meth)acrylic acid ester with a high refractive index, and specifically, the refractive index nA of the component (A) is 1.50 to 1.65, preferably 1.50 to 1.60, and particularly preferably 1.55 to 1.60.

[0044] (A) By making the refractive index of the component within this range, an anisotropic optical film with excellent diffusivity can be manufactured.

[0045] In addition, component (A) is a (meth)acrylic acid ester having one or more aromatic rings and (meth)acryloyl groups.

[0046] (A) The number of (meth)acryloyl groups included in the component is not particularly limited, but can be 1 or 2 or more, and as an upper limit, it is not particularly limited, but it is preferable to have 8 or fewer.

[0047] (A) It is preferable that the component has multiple aromatic rings. As a structure containing multiple aromatic rings, it is preferable that it has a biphenyl ring structure and / or a diphenyl ether structure. In the backbone, there may be only one such biphenyl structure or diphenyl ether structure, or two or more such structures. By having such a structure, it becomes a (meth)acrylic acid ester having a very high refractive index.

[0048] Examples of such (A) components include, but are not particularly limited, a biphenyl compound represented by the following general formula (1) or a diphenyl ether compound represented by the following general formula (2).

[0049]

[0050]

[0051] In general formula (1), R 1 ~R 10 are, each independently, and R 1 ~R 10 One of them is a substituent represented by the following general formula (3) or (4). The remainder does not contain a (meth)acryloyl group, and specifically, substituents such as hydrogen atoms, hydroxyl groups, carboxyl groups, alkyl groups, alkoxy groups, alkyl halide groups, hydroxyalkyl groups, carboxyalkyl groups, and halogen atoms may be used.

[0052] Also, among general formula (2), R 11 ~R 20 are, each independently, and R 11 ~R 20 One of them is a substituent represented by the following general formula (3) or (4). The remainder does not contain a (meth)acryloyl group, and specifically, substituents such as hydrogen atoms, hydroxyl groups, carboxyl groups, alkyl groups, alkoxy groups, alkyl halide groups, hydroxyalkyl groups, carboxyalkyl groups, and halogen atoms may be used.

[0053]

[0054] (of general formula (3), R 21 It is silver, a hydrogen atom, or a methyl group, where n is an integer from 1 to 4, and the number of repetitions m is an integer from 1 to 10.)

[0055]

[0056] (of general formula (4), R 22 is a hydrogen atom or a methyl group, n is an integer from 1 to 4, and the number of repetitions m is an integer from 1 to 10.)

[0057] In the substituents represented by the above general formulas (3) and (4), the number of repetitions m is preferably an integer from 1 to 10, more preferably an integer from 1 to 4, and even more preferably an integer from 1 to 2.

[0058] Likewise, in the substituents represented by general formulas (3) and (4), it is generally preferable to make n an integer from 1 to 4, and more preferably an integer from 1 to 2.

[0059] A specific example of the biphenyl compound represented by the above general formula (1) is preferably a compound represented by the following formula (5).

[0060]

[0061] A specific example of the diphenyl ether compound represented by the above general formula (2) is preferably a compound represented by the following formula (6).

[0062]

[0063] (A-2) The component may include only one type of the component described above, or it may include multiple types.

[0064] <<(B) Component>>

[0065] (B) is a low-refractive-index material having a relatively low refractive index, specifically, the refractive index nB of component (B) is 1.35 to 1.54, preferably 1.35 or higher and less than 1.50, more preferably 1.40 or higher and less than 1.50, and particularly preferably 1.45 or higher and less than 1.50. Additionally, in the present invention, the refractive index nB of component (B) is smaller than the refractive index nA of component (A).

[0066] The difference (nA-nB) between the refractive index nA of component (A) and the refractive index nB of component (B) is preferably 0.01 to 0.3, more preferably 0.03 to 0.3, and particularly preferably 0.05 to 0.3.

[0067] (B) The component is not particularly limited as long as it satisfies the above refractive index, and known resin materials may be used. Examples include acrylic resin, styrene resin, styrene-acrylic copolymer, polyurethane resin, polyester resin, epoxy resin, cellulose-based resin, silicone-based resin, vinyl acetate-based resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, polyvinyl alcohol resin, polyvinyl formal resin, polyvinyl acetal resin, polyvinylidene fluoride, etc. As for the component (B), it is preferable that it be a copolymer, and preferably an acrylic copolymer. In this case, it is more preferable that the content of (meth)acrylic acid ester in the constituent monomer is 10% by weight to 80% by weight.

[0068] (B) The component is preferably a urethane (meth)acrylic acid ester composed of a cyclic aliphatic compound having two isocyanate groups, a polyol compound (preferably a diol compound, particularly preferably a polyalkylene glycol), and a hydroxyalkyl (meth)acrylic acid ester.

[0069] Examples of cyclic aliphatic compounds having two isocyanate groups include isophorone diisocyanate (IPDI) and hydrogenated diphenylmethane diisocyanate, which are alicyclic polyisocyanates.

[0070] Examples of polyol compounds include polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexylene glycol, etc., and polypropylene glycol is preferred.

[0071] Examples of hydroxyalkyl (meth)acrylic acid esters include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.

[0072] (B) The component can be synthesized and manufactured according to the commercial law of each component described above.

[0073] Additionally, the ratio of the amounts of each component is not particularly limited, but for example, it is preferable to have a molar ratio of “cyclic aliphatic compound having two isocyanate groups”: “polyol compound”: “hydroxyalkyl (meth)acrylic acid ester” = 1~5:1:1~5.

[0074] (B) The component is preferably a thermoplastic polymer. In addition, the glass transition temperature of the component (B) is preferably -40°C or higher, more preferably 0°C or higher, and particularly preferably 30°C or higher. The upper limit of the glass transition temperature is not particularly limited, but, for example, it is preferably 150°C or lower.

[0075] The glass transition temperature can be measured by a known measurement method, for example, a method based on JIS K7121-1987 “Method for measuring the transition temperature of plastics”.

[0076] (B) The weight average molecular weight of the component is preferably 1,000 to 500,000, more preferably 2,000 to 50,000, and more preferably 3,000 to 20,000.

[0077] The weight-average molecular weight can be measured using a known measurement method, for example, the GPC method as the polystyrene equivalent molecular weight.

[0078] (B) By setting the glass transition temperature and weight average molecular weight of the component to the above range, compatibility with component (A) can be increased, and an anisotropic optical film of excellent performance can be produced. For example, it is possible to improve durability in heat resistance tests, etc., and to enable storage in a roll that has a suitable elastic modulus for the anisotropic optical film before UV curing.

[0079] (B) The component may contain only one type of the component described above, or it may contain multiple types. Additionally, if the component (B) consists of multiple components, the refractive index of the component (B) may be the average of those components.

[0080] <<(C) Component>>

[0081] (C) Component is a polymerization initiator.

[0082] (C) The polymerization initiator of the component is a compound that generates radical species upon irradiation with active energy rays such as ultraviolet rays, and a conventionally known one may be used.

[0083] As polymerization initiators, for example, benzophenone, benzyl, mihler ketone, 2-chlorothioxantone, 2,4-diethylthioxantone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzyl dimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1,1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, bis(cyclopenta Examples include dienyl)-bis[2,6-difluoro-3-(phil-1-yl)phenyl]titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2,4,6-trimethylbenzoyl diphenyl phosphine oxide, etc.

[0084] These compounds may be used individually or in combination.

[0085] The polymerization initiator may be used by directly dissolving the powder in the polymerizable compound, but if the solubility is poor, the polymerization initiator may be used after being dissolved in a solvent in advance.

[0086] <<(D) Component>>

[0087] (D) The component is a polymerization inhibitor having a structure in which a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound.

[0088] Examples of polymerization inhibitors having the above structure include so-called quinone-based or phenol-based polymerization inhibitors.

[0089] Specifically, the (D) component is preferably one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6).

[0090]

[0091] In formulas (D1) to (D6), R1 to R5 are each independently a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 (preferably C1 to C3) alkoxy group (e.g., methoxy group, ethoxy group, propyloxy group) or an alkyl group (e.g., methyl group, ethyl group, propyl group, or tert-butyl group).

[0092] Accordingly, component (D) is preferably a polymerization inhibitor of the hydroquinone type (e.g., formula (D1)), quinone methide type (e.g., formulas (D2) and (D4)), benzoquinone type (e.g., formula (D3)), phenol type (e.g., formula (D5)), or catechol type (e.g., formula (D6)). Furthermore, component (D) is more preferably a polymerization inhibitor of the hydroquinone type, quinone methide type, or benzoquinone type, and is particularly preferably a polymerization inhibitor of the benzoquinone type.

[0093] Since the polymerization inhibitor only needs to have a structure with an added carbonyl group or a hydroxyl group, in addition to the above formulas (D1) to (D6), polymerization inhibitors such as pyrogallol-based and naphthoquinone-based polymerization inhibitors can also be used.

[0094] In a composition for an anisotropic optical film containing a high-refractive index material (A) and a polymerization initiator, by additionally including a predetermined polymerization inhibitor, the growth of the structural region described below becomes appropriate, thereby enabling an effect of improving optical properties (especially, diffusion width).

[0095] Other ingredients

[0096] As other components, various known dyes or sensitizers, or other known additives, may be included to enhance photopolymerization. Additionally, solvents or dispersion media may be included.

[0097] In addition, a thermal curing initiator capable of curing a photopolymerizable compound by heating may be used in combination with a photopolymerization initiator. In this case, heating after photocuring can further accelerate the polymerization curing of the photopolymerizable compound, thereby making it complete.

[0098] As a solvent when preparing a composition containing a photopolymerizable compound, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, etc. may be used.

[0099] In addition, if an acid-generating agent used as an initiator for cationic polymerization remains after the composition is cured, there is a possibility that it may cause defects in other parts when used in devices such as displays. Therefore, it is preferable that the other components do not include an acid-generating agent. For example, it is preferable that the content of the acid-generating agent in the composition be 1% or less.

[0100] <<<Content of each ingredient>>>

[0101] <<(A) Component>>

[0102] The content of component (A) relative to the total solid content of the composition (the total amount of non-volatile components excluding volatile solvents) is not particularly limited, but is preferably 30 wt% or more, 35 wt% or more, 40 wt% or more, or 45 wt% or more. The upper limit is not particularly limited, but is, for example, 99 wt%, 95 wt%, 90 wt%, 85 wt%, 80 wt%, 70 wt%, or 60 wt%.

[0103] <<(B) Component>>

[0104] The content of component (B) in the composition is preferably 10 to 400 parts by weight when the content of component (A) is 100 parts by weight, more preferably 25 to 200 parts by weight, and particularly preferably 50 to 100 parts by weight.

[0105] In addition, according to another perspective, the content of component (B) relative to the total amount of non-volatile components of the composition (amount excluding solvent or dispersion medium) is preferably 10 to 80 weight%, preferably 15 to 70 weight%, and more preferably 20 to 60 weight%.

[0106] <<(C) Component>>

[0107] The content of component (C) in the composition is preferably 0.1 to 20 parts by weight when the amount of non-volatile components of the composition is 100 parts by weight, more preferably 0.5 to 15 parts by weight, and particularly preferably 1 to 10 parts by weight.

[0108] In addition, according to another perspective, the content of component (C) relative to the total amount of non-volatile components of the composition is preferably 0.1% to 10% by weight, more preferably 0.5% to 8% by weight, and particularly preferably 0.8% to 5% by weight.

[0109] <<(D) Component>>

[0110] The content of component (D) in the composition is preferably 0.001 to 1 part by weight when the amount of non-volatile components of the composition is 100 parts by weight, more preferably 0.005 to 0.5 parts by weight, even more preferably 0.008 to 0.1 parts by weight, and particularly preferably 0.015 to 0.05 parts by weight.

[0111] In addition, according to another perspective, the content of component (D) in the composition relative to the total amount of non-volatile components of the composition is preferably 0.001 wt% to 0.5 wt%, more preferably 0.005 wt% to 0.1 wt%, and particularly preferably 0.01 wt% to 0.04 wt%.

[0112] Additionally, among the composition, the ratio represented as [content of component (D) / content of component (C)] is preferably 0.005 to 0.1, and more preferably 0.01 to 0.05.

[0113] By setting the content of each component in the above range, the composition for an anisotropic optical film according to the present invention makes it possible to obtain an anisotropic optical film having excellent diffusivity.

[0114] <<<<Anisotropic Optical Film>>>>

[0115] Next, suitable examples of anisotropic optical films that can be obtained using a composition for anisotropic optical films will be described. Additionally, by using a composition for anisotropic optical films, it is possible to manufacture anisotropic optical films other than the anisotropic optical films shown below.

[0116] An "anisotropic optical film" possesses incident angle-dependent anisotropy and directivity, in which the diffusion, transmission, and diffusion distribution of light change according to the incident angle. Therefore, it is different from directional diffusion films that are not dependent on the incident angle, isotropic diffusion films, and diffusion films oriented in a specific orientation.

[0117] In the angle-dependent nature of incident light in an anisotropic optical film, linear transmittance [percentage of (amount of light transmitted in the linear direction of incident light) / (amount of incident light)] changes depending on the angle of incidence. That is, for incident light on an anisotropic optical film, incident light within a certain angle range is mainly transmitted because linearity is high, while incident light within other angle ranges is mainly diffused because diffusivity is high.

[0118] <<<Structure>>>

[0119] The anisotropic optical film in the present invention has a matrix region and a plurality of columnar regions with a refractive index different from that of the matrix region.

[0120] The “matrix region” and “multiple columnar regions” within the anisotropic optical film are regions formed by differences in the local refractive index of the material constituting the anisotropic optical film according to the present invention, and are relative to whether the refractive index is lower or higher compared to the other side. These regions are formed by phase separation when the material forming the anisotropic optical film is cured.

[0121] In other words, the difference in refractive index is not particularly limited, provided that at least a portion of the light incident on the anisotropic optical film differs to the extent that reflection occurs at the interface between the matrix region and the columnar region.

[0122] A plurality of columnar regions included in an anisotropic optical film are typically oriented and arranged in series from one surface of the anisotropic optical film to the other (see FIG. 1).

[0123] <<Main Area>>

[0124] The length of the columnar region is not particularly limited and may be a length that penetrates from one surface of the anisotropic optical film to the other, or a length that does not reach from one surface to the other.

[0125] A plurality of columnar regions of an anisotropic optical film can have a surface shape in the anisotropic optical film having a short axis and a long axis.

[0126] The surface shape of the columnar region is not particularly limited, for example,

[0127] It can be circular, elliptical, or polygonal. In the case of a circular shape, the minor axis and the major axis are equal; in the case of an elliptical shape, the minor axis is the length of the minor axis and the major axis is the length of the major axis; and in the case of a polygon, the shortest length connecting two points on the outer edge of the polygon within the polygon can be the minor axis and the longest length can be the major axis. Figure 2 shows a columnar region viewed from the surface direction of an anisotropic optical film. In Figure 2, LA represents the major axis and SA represents the minor axis.

[0128] The short and long axes of the columnar regions can be determined by observing the surface of the anisotropic optical film with an optical microscope, measuring the short and long axes of each of the 20 randomly selected columnar regions, and taking the average of these values.

[0129] The ratio of the average major axis to the average minor axis of the columnar region (average major axis / average minor axis), i.e., the aspect ratio, is not particularly limited, but, for example, it is preferably 1 to 50, and more preferably 2 to 20.

[0130] FIG. 2 (a) shows an anisotropic optical film with an aspect ratio of the columnar region of 2 to 50, and FIG. 2 (b) shows an anisotropic optical film with an aspect ratio of the columnar region of 1 or more and less than 2.

[0131] When the aspect ratio is 1 or greater and less than 2, the transmitted light diffuses isotropically when light parallel to the principal axis direction of the columnar region is irradiated (see FIG. 1 (a)). On the other hand, when the aspect ratio is 2 to 50, the light diffuses anisotropically according to the aspect ratio when light parallel to the principal axis direction is irradiated in the same way (see FIG. 1 (b)).

[0132] In addition, when the aspect ratio is set to 2 to 50, if the aspect ratio is set to a range of 20 to 50 or less, it exhibits greater anisotropy and diffusion, whereas if the aspect ratio is set to a range of 2 to 20, it exhibits properties intermediate to those of the case where the aspect ratio is 1 or more and less than 2, and the case where the aspect ratio is greater than 20 and less than 50. In this way, by classifying the range of the aspect ratio into 1 or more and less than 2, 2 to 20, and greater than 20 and less than 50, it is possible to produce anisotropic optical films having different optical properties. The composition for anisotropic optical films according to the present invention can be used as a preferred raw material in the manufacture of anisotropic optical films having any aspect ratio.

[0133] The anisotropic optical film may include a plurality of columnar regions having one aspect ratio, or a plurality of columnar regions having different aspect ratios.

[0134] <<<Spawning Central Axis>>>

[0135] The "scattering center axis" of an anisotropic optical film refers to the direction that coincides with the angle of incidence of light, which exhibits approximate symmetry with respect to that angle of incidence when the angle of incidence of light on the anisotropic optical film is varied. The phrase "exhibits approximate symmetry" is used because, if the scattering center axis is inclined with respect to the normal direction of the film (the direction of the film's thickness), the optical profile regarding light diffusion (described later) does not strictly possess symmetry.

[0136] Here, the scattering center axis and the orientation direction of the columnar region (columnar direction) are typically in a parallel relationship. Additionally, the fact that the scattering center axis and the orientation direction of the columnar region are parallel is sufficient if they satisfy the law of refractive index (Snell's law), and they do not need to be strictly parallel.

[0137] The scattering center axis can be identified by observing the principal axis tilt of the columnar region in the cross-section of the anisotropic optical film using an optical microscope, or by observing the projected shape of light passing through the anisotropic optical film by changing the angle of incident light, in addition to by the optical profile.

[0138] Snell's law states that when light is incident on the interface of a medium with a refractive index (n1) to a medium with a refractive index (n2), the relationship n1sinθ1=n2sinθ2 holds between the angle of incidence (θ1) and the angle of refraction (θ2). For example, if n1=1 (air) and n2=1.51 (anisotropic optical film), when the angle of incidence is 30°, the orientation direction (angle of refraction) of the columnar region becomes approximately 19°. However, even if the angle of incidence and the angle of refraction are different, if Snell's law is satisfied, it is included in the concept of parallelism in the present invention.

[0139] As described above, the scattering center axis refers to the direction in which the incident light angle coincides with the incident light angle of light, which has approximately symmetry with respect to the incident light angle when the incident light angle to the anisotropic optical film is changed. Additionally, the scattering center axis at this time can be determined by calculating the linear transmittance based on the incident light angle to the anisotropic optical film, creating an optical profile which is a graph representing the relationship, and setting the incident light angle at approximately the center (the center of the diffusion region, approximately 17° in the case of Example 1 of Fig. 6) which is located at the minimum value of the linear transmittance in the optical profile (as an example, Fig. 6 showing the optical profile in the example).

[0140] Although the optical profile does not directly express light diffusivity, if we interpret that diffuse transmittance increases as linear transmittance decreases, it can be said that it generally exhibits light diffusivity.

[0141] In addition, as shown in FIG. 6, the range of two incident light angles for the intermediate linear transmittance between the extreme values ​​of the two minimum values ​​of the maximum linear transmittance is called the “diffuse region,” and the range of incident light angles other than that is called the “non-diffuse region.”

[0142] In addition, in the present invention, the diffusion region is referred to as the “diffusion width.”

[0143] Next, referring to FIG. 3, the scattering center (P) in an anisotropic optical film will be explained from a different viewpoint. FIG. 3 is a three-dimensional polar coordinate representation for explaining the scattering center axis (P) in an anisotropic optical film.

[0144] The scattering center axis can be expressed by the polar angle (θ) and the azimuth angle (φ) according to the three-dimensional polar coordinate representation as shown in FIG. 3, where the surface of the anisotropic optical film is the xy plane and the normal to the surface of the anisotropic optical film is the z-axis. That is, Pxy in FIG. 3 can be said to be the longitudinal direction of the scattering center axis projected onto the surface of the principal plane of the anisotropic optical film.

[0145] Here, the polar angle (θ) (-90° < θ < 90°) formed by the normal of the anisotropic optical film (z-axis shown in FIG. 3) and the columnar region can be defined as the scattering center axis angle. In a process of photocuring an uncured resin composition layer to form a columnar region, the angle of the columnar axis direction of the columnar region can be adjusted to a desired range by changing the direction of the irradiated light.

[0146] <<<Thickness>>>

[0147] The thickness of the anisotropic optical film is not particularly limited, but is preferably 10 μm to 500 μm, and more preferably 10 μm to 200 μm.

[0148] <<<<Method for Manufacturing Anisotropic Optical Film>>>>

[0149] Next, a method for manufacturing an anisotropic optical film using a composition for an anisotropic optical film will be described.

[0150] First, a composition for an anisotropic optical film (hereinafter referred to as a "photocurable resin composition") is applied onto a suitable substrate, such as a transparent PET film, to form a sheet, and then, if necessary, dried to volatilize the solvent to provide an uncured resin composition layer. By irradiating light onto this uncured resin composition layer, an anisotropic optical film can be produced.

[0151] More specifically, the process for forming an anisotropic optical film mainly comprises the following processes.

[0152] (1) Process 1-1: Process of preparing an uncured resin composition layer on a gaseous phase

[0153] (2) Process 1-2: Process of obtaining parallel rays from a light source

[0154] (3) Arbitrary process 1-3: Process for obtaining a directional beam

[0155] (4) Process 1-4: Process for curing the uncured resin composition layer

[0156] <<<Process 1-1: Process of preparing an uncured resin composition layer on a gaseous phase>>>

[0157] A method for preparing a photocurable resin composition as a sheet-like layer of uncured resin composition on a gaseous phase may be applied using a conventional coating method or a printing method. Specifically, coatings such as air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calender coating, dam coating, dip coating, die coating, or printing methods such as intaglio printing (e.g. gravure printing) or stencil printing (e.g. screen printing) may be used. In the case where the composition has low viscosity, a dike of a certain height may be provided around the gaseous phase, and the composition may be cast within the area surrounded by this dike.

[0158] In process 1-1, in order to prevent oxygen inhibition of the uncured resin composition layer and to efficiently form a columnar region which is a characteristic of an anisotropic optical film, it is also possible to laminate a mask that locally changes the irradiation intensity of light by adhering to the light irradiation side of the uncured resin composition layer.

[0159] As for the material of the mask, it is preferable to have a configuration in which a light-absorbing filler, such as carbon, is dispersed within a matrix, such that a portion of the incident light is absorbed by the carbon, while the openings allow sufficient light to pass through. As such a matrix, it may be a transparent plastic such as PET, TAC, PVAc, PVA, acrylic, or polyethylene, an inorganic material such as glass or quartz, or a sheet containing these matrices that includes a pattern for controlling the amount of ultraviolet light transmittance or a pigment that absorbs ultraviolet light.

[0160] In cases where such a mask is not used, it is also possible to prevent oxygen inhibition of the uncured resin composition layer by performing light irradiation under a nitrogen atmosphere. Furthermore, simply laminating a conventional transparent film onto the uncured resin composition layer is effective in preventing oxygen inhibition and promoting the formation of columnar regions. In light irradiation involving such a mask or transparent film, a photopolymerization reaction according to the irradiation intensity occurs within the composition containing the photopolymerizable compound, making it easy to induce a refractive index distribution, which is effective for producing an anisotropic optical film according to the present embodiment.

[0161] <<Process 1-2: Process of obtaining parallel rays from a light source>>

[0162] As a light source, a short arc ultraviolet generating light source is typically used, and specifically, high-pressure mercury lamps, low-pressure mercury lamps, meta-halide lamps, xenon lamps, etc., can be used. At this time, it is necessary to obtain a light ray parallel to the desired scattering center axis; such a parallel light ray can be obtained, for example, by placing a point light source and placing an optical lens such as a Fresnel lens between the point light source and the uncured resin composition layer to irradiate the parallel light ray, or by placing a reflector behind the light source to emit it as a point light source in a predetermined direction.

[0163] <<<Arbitrary Process 1-3: Process for Obtaining Directional Rays>>>

[0164] Optional process 1-3 is a process of injecting parallel light rays into a directional diffusion element to obtain a directional light ray. FIG. 5 is a schematic diagram illustrating a method for manufacturing an anisotropic optical film according to the present invention, comprising optional process 1-3.

[0165] The directional diffusion elements (11 and 12) used in arbitrary processes 1-3 only need to impart directionality to the parallel light rays (A) incident from the light source (10).

[0166] FIG. 5 describes that directional light (B1 or B2) is incident on an uncured resin composition layer (1) in a manner where it diffuses significantly in the x-direction and hardly diffuses in the y-direction. To obtain such directional light, for example, a method may be adopted in which needle-shaped fillers with a high aspect ratio are contained within the directional diffusion elements (11 and 12), and said needle-shaped fillers are oriented so that their major axis direction extends in the y-direction. Various methods may be used for the directional diffusion elements (11 and 12) in addition to the method of using needle-shaped fillers.

[0167] Here, it is preferable that the aspect ratio of the directional light be 2 to 50. A columnar region having an aspect ratio that corresponds almost to said aspect ratio is formed.

[0168] In arbitrary processes 1-3, the size of the formed columnar region (aspect ratio, short axis (SA), long axis (LA), etc.) can be appropriately determined by adjusting the magnification of the directional light. For example, an anisotropic optical film of this form can be obtained in either (a) or (b) of FIG. 5. The difference between FIG. 5 (a) and (b) is that the magnification of the directional light is large in (a) (B1) and small in (b) (B2). The size of the columnar region varies depending on the magnitude of the magnification of the directional light.

[0169] Directional light expansion depends mainly on the type of directional diffusion element (11 and 12) and the distance from the uncured resin composition layer (1). As the distance is shortened, the size of the columnar region becomes smaller, and as the distance is lengthened, the size of the columnar region becomes larger. Therefore, the size of the columnar region can be adjusted by adjusting the distance.

[0170] <<<Process 1-4: Process of curing the uncured resin composition layer>>>

[0171] The light irradiated onto an uncured resin composition layer to cure it must include a wavelength capable of curing the photopolymerizable compound, and typically, light with a wavelength centered at 365 nm, such as from a mercury lamp, can be used. When fabricating an anisotropic optical film using this wavelength range, the illuminance is 0.01 mW / cm² 2 ~100mW / cm 2 The range is desirable, and 0.1 mW / cm² 2 ~20mW / cm 2 A is more desirable. Illuminance of 0.01 mW / cm² 2 If it is less than 100 mW / cm², production efficiency deteriorates because curing requires a long time, and 100 mW / cm² 2 This is because if it exceeds the limit, the curing of the photopolymerizable compound is too fast and does not cause structure formation, so the desired optical properties cannot be expressed.

[0172] Additionally, the irradiation time of the light is not particularly limited, but is preferably 10 to 180 seconds, and more preferably 30 to 120 seconds. By irradiating with the above light, an anisotropic optical film of this form can be obtained.

[0173] An anisotropic optical film can be obtained by forming a specific internal structure within the uncured resin composition layer through irradiation with low-intensity light for a relatively long period of time, as described above, even when performing optional processes 1-3. Consequently, unreacted monomer components may remain due to such light irradiation alone, causing stickiness or resulting in problems with handling properties or durability. In such cases, 1000 mW / cm² 2 The remaining monomer can be polymerized by additionally irradiating with light of the above high intensity. At this time, the light irradiation may be performed from the side opposite to the side where the mask is laminated.

[0174] As described above, when curing the uncured resin composition layer, the scattering center axis of the anisotropic optical film that can be obtained can be made desired by adjusting the angle of light irradiated onto the uncured resin composition layer.

[0175] Additionally, the anisotropic optical film may have other layers (adhesive layer, functional layer, transparent film layer, etc.).

[0176] <<<<Applications of Anisotropic Optical Films>>>>

[0177] Anisotropic optical films can be applied to all display devices, such as liquid crystal displays, organic EL displays, and plasma displays, as they offer excellent improvement in visual dependency. Additionally, by using anisotropic optical films in reflective liquid crystal displays, it is possible to expect an effect that increases reflective brightness in a specific direction. Furthermore, anisotropic optical films can also be applied to lighting fixtures, building materials, and the like.

[0178] Examples

[0179] Next, the present invention will be explained in more detail by way of examples and comparative examples, but the present invention is not limited in any way by these examples.

[0180] (Manufacturing of anisotropic optical films)

[0181] According to the following method, the anisotropic optical film of the present invention and the anisotropic optical film of the comparative example were manufactured.

[0182] [Example 1]

[0183] <<1. Preparation of Solution 1, Composition for Anisotropic Optical Films>>

[0184] Anisotropic optical film composition solution 1 was obtained by mixing and stirring various materials shown below, each in the mixing amounts shown below.

[0185] <(A) Component>

[0186] m-phenoxybenzyl acrylate

[0187] Refractive index: 1.57

[0188] 55 parts by weight

[0189] <(B) Component>

[0190] A copolymer composed of polymethyl methacrylate (PMMA) and polybutyl acetate (a copolymer having 50% (meth)acrylate)

[0191] Refractive index: 1.48

[0192] Weight-average molecular weight: 37,000

[0193] Glass transition temperature: -30℃

[0194] 45 parts by weight

[0195] <(C) Component>

[0196] 2,2-Dimethoxy-2-phenylacetophenone (Manufactured by IGM Resins BV, Trade Name: Omnirad 651)

[0197] (When the amount of the non-volatile component of the composition is 100 parts by weight) 1.3 parts by weight

[0198] <(D) Component>

[0199] 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Kasei Kogyo Co., Ltd., benzoquinone-based polymerization inhibitor)

[0200] (When the amount of the non-volatile component of the composition is 100 parts by weight) 0.02 parts by weight

[0201] <Solvent>

[0202] Butyl acetate

[0203] 71 parts by weight

[0204] <<2. Preparation of Composition 1 for Anisotropic Optical Film>>

[0205] A composition solution 1 for an anisotropic light diffusion film obtained was applied to a PET film (manufactured by Toyobo Co., Ltd., trade name: A4300) with a thickness of 100 μm using an applicator, and then the coating was dried in a clean oven with the internal temperature set to 80°C, thereby obtaining a composition 1 for an anisotropic optical film with a film thickness of 50 μm.

[0206] <<3. Fabrication of Anisotropic Optical Film 1>>

[0207] Next, a polyvinyl alcohol film with carbon uniformly dispersed therein (hereinafter referred to as a PVA mask) was laminated using a laminator on the surface that was not in contact with the PET film of Composition 1 for an anisotropic optical film. The obtained laminate was heated to 70°C, and while maintaining the temperature constant, parallel rays emitted from a projecting irradiation unit (manufactured by Hamamatsu Photonics, Trade Name: L2859-01) from the surface of the PVA mask were converted into linear rays through a directional diffusion element having an aspect ratio of 5, and an irradiation intensity of 2 mW / cm² was applied. 2 The light was irradiated for 30 seconds. At this time, the angle of irradiation was a direction perpendicular to the direction in which the light diffuses into the directional diffusion element and the thickness direction of the anisotropic optical film composition 1 (hereinafter referred to as the MD direction), and irradiated at a direction tilted 11.5° from the normal direction of the anisotropic optical film composition 1.

[0208] From the obtained laminate, the above-described PVA mask and PET film were peeled off to obtain the anisotropic optical film 1 of Example 1.

[0209] [Example 2]

[0210] The anisotropic optical film 2 of Example 2 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.01 parts by weight of 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0211] [Example 3]

[0212] The anisotropic optical film 3 of Example 3 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.006 parts by weight of 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0213] [Example 4]

[0214] The anisotropic optical film 4 of Example 4 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.02 parts by weight of tetramethyl-1,4-benzoquinone (TMBQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0215] [Example 5]

[0216] The anisotropic optical film 5 of Example 5 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.01 parts by weight of tetramethyl-1,4-benzoquinone (TMBQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0217] [Example 6]

[0218] The anisotropic optical film 6 of Example 6 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.01 parts by weight of methyl hydroquinone (MHQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0219] [Example 7]

[0220] The anisotropic optical film 7 of Example 7 was obtained by performing the same method as in Example 1, except that component (D) of the formulation of Example 1 was changed to 0.1 parts by weight of 2,5-di-t-butyl-1,4-hydroquinone (DBHQ) (Tokyo Kasei Kogyo Co., Ltd.).

[0221] [Example 8]

[0222] In the formulation of Example 1, the process was carried out in the same manner as in Example 1, except that component (D) was changed to 0.06 parts by weight of Irgastab UV22 (BASF Japan Co., Ltd.), and an anisotropic optical film 8 of Example 8 was obtained. Additionally, Irgastab UV22 is a mixture of paraquinone methide and oroquinone methide.

[0223] [Example 9]

[0224] The anisotropic optical film 9 of Example 9 was obtained by performing the same method as in Example 1, except that the anisotropic optical film 1 was converted into a linear light beam through a directional diffusion element in which the aspect ratio of the light beam is less than 2 and the heating temperature was changed to 50°C.

[0225] [Example 10]

[0226] Except for converting the light beam into a linear light beam through a directional diffusion element with an aspect ratio of 10 during the fabrication of the anisotropic optical film 1, the process was carried out in the same manner as in Example 1 to obtain the anisotropic optical film 10 of Example 10.

[0227] [Example 11]

[0228] The anisotropic optical film 11 of Example 11 was obtained by performing the same method as Example 1, except that the anisotropic optical film 1 was converted into a linear light beam through a directional diffusion element in which the aspect ratio of the light beam was 30 during the fabrication of the anisotropic optical film 1.

[0229] [Example 12]

[0230] The anisotropic optical film 12 of Example 12 was obtained by performing the same method as in Example 1, except that component (A) in the formulation of Example 1 was changed to 2-hydroxy-3-phenoxypropyl acrylate (refractive index: 1.52).

[0231] [Example 13]

[0232] The anisotropic optical film 13 of Example 13 was obtained by performing the same method as in Example 1, except that component (B) in the formulation of Example 1 was changed to an acrylic block copolymer (a copolymer having 20% ​​(meth)acrylate).

[0233] <(B) Component>

[0234] Refractive index: 1.44

[0235] Weight-average molecular weight: 43,000

[0236] Glass transition temperature: -30℃

[0237] [Example 14]

[0238] The anisotropic optical film 14 of Example 14 was obtained by performing the same method as in Example 1, except that component (B) in the formulation of Example 1 was changed to a thermoplastic polymer (polyvinyl acetate).

[0239] <(B) Component>

[0240] Refractive index: 1.46

[0241] Average molecular weight: 200,000

[0242] Glass transition temperature: 40℃

[0243] [Example 15]

[0244] In the formulation of Example 1, the anisotropic optical film 15 of Example 15 was obtained by performing the same method as in Example 1, except that component (B) of the formulation of Example 1 was changed to a urethane (meth)acrylic acid ester composed of polypropylene glycol (PPG), isophorone diisocyanate (IPDI), and 2-hydroxyethyl methacrylate (HEMA) (a copolymer in which the content of (meth)acrylic acid ester in the constituent monomers is 40 wt%).

[0245] <(B) Component>

[0246] Refractive index: 1.46

[0247] Weight-average molecular weight: 10,000

[0248] [Example 16]

[0249] Except for excluding component (B) from the formulation of Example 1, the same method as in Example 1 was performed to obtain the anisotropic optical film 16 of Example 16.

[0250] [Comparative Examples 1–16]

[0251] (D) Comparative anisotropic optical films 1 to 16 of Comparative Examples 1 to 16 were obtained in the same manner as in Examples 1 to 16, except that no component was added.

[0252] The types of component (D) in each example and the content of component (D) per 100 parts by weight of the non-volatile component of the composition are summarized and shown in Table 1.

[0253]

[0254] (Evaluation Method)

[0255] The following evaluation was performed on the anisotropic optical films of the embodiments and comparative examples of the present invention manufactured as described above.

[0256] [Evaluation of Light Diffusivity]

[0257] Light diffusivity was evaluated using the diffusion width. The diffusion width was calculated by the following method.

[0258] The light diffusivity of the anisotropic optical films of the examples and comparative examples was evaluated using a variable-angle photometer goniophotometer (manufactured by Genesia Co., Ltd.) capable of arbitrarily varying the light transmission angle of the light source and the light reception angle of the detector, as shown in FIG. 4. As shown in FIG. 4, the anisotropic optical films of the examples and comparative examples (sample 3) were placed between a light source (1) and a detector (2) (where the light source (1) and the detector (2) are each fixed). In this evaluation, the incident angle was set to 0° when the irradiated light (I) from the light source (1) was incident in the normal direction of the anisotropic optical film (sample 3), and the anisotropic optical film (sample 3) was arranged so that it could be arbitrarily rotated with the TD direction shown in FIG. 1 as the central axis.

[0259] Next, the anisotropic optical film (Sample 3) of the arranged example and comparative example was rotated continuously by 1° in the range of -75° to 75°, and the amount of light transmitted in the straight direction (linear transmitted light amount) at each incident light angle was measured. In addition, the measurement of the amount of linear transmitted light can be obtained by measuring the wavelength in the visible light region using a visual sensitivity filter. Then, the ratio of the amount of linear transmitted light to the amount of linear transmitted light (amount of incident light, incident light amount) directly irradiated from the light source (1) to the detector (2) without passing through the anisotropic optical film (Sample 3) was defined as the linear transmittance (%).

[0260] As a result of the above measurements, an optical profile could be obtained from the acquired data, and based on this optical profile, the maximum (maximum linear transmittance) and minimum (minimum linear transmittance) values ​​of linear transmittance were calculated.

[0261] At this time, the diffusion width was calculated by the linear transmittance, which is the ratio of the linear transmittance to the incident light amount of the anisotropic optical film, wherein the linear transmittance shows a minimum value at two points and the angle difference between the two minimum values.

[0262] Here, in the optical profile, the normal direction of the anisotropic optical film is set to 0°, and the angle of incident light is indicated in the negative and positive directions. Therefore, the angle of incident light may have a negative value.

[0263] Here, when the values ​​of the two incident light angles are “plus incident light angle value and minus incident light angle value,” the “sum of the absolute value of the minus incident light angle value and the plus incident light angle value” is defined as the diffusion width, which is the angle range of the incident light angle.

[0264] In addition, when the values ​​of the two incident light angles are “both positive,” the “difference between the larger value and the smaller value” is defined as the diffusion width, which is the angle range of the incident light angles.

[0265] In addition, when the values ​​of the two incident light angles are “both negative,” the “difference between the larger value and the smaller value by taking the absolute value of each” is defined as the angle range of the incident light angles.

[0266] [Measurement of aspect ratio in the columnar region (Observation of the surface of the anisotropic light diffusion layer)]

[0267] The surface of the anisotropic optical film of the example and comparative example (the side exposed to ultraviolet light during fabrication) was observed with an optical microscope, and the major axis (LA) and minor axis (SA) of a plurality of columnar regions were measured in 20 optional columnar region divisions. The average values ​​of the measured major axis (LA) and minor axis (SA) were calculated, and the average major axis (LA) / average minor axis (SA) was calculated as the aspect ratio of the columnar regions.

[0268] [metewand]

[0269] For each diffusion width of anisotropic optical films 1 to 16 of the examples, the difference in diffusion width between each diffusion width of comparative anisotropic optical films 1 to 16 of comparative examples, which were prepared in the same manner as the examples except that component (D) was not added to the composition, and the difference in diffusion width due to the presence or absence of component (D) was calculated for each example and evaluated according to the following evaluation criteria.

[0270] ◎: Excellent diffusivity 10° or higher

[0271] ○: Excellent diffusivity 5° or more, less than 10°

[0272] △: Diffusivity that poses no practical problems 0° or more, less than 5°

[0273] Х: Insufficient diffusivity, less than 0°

[0274] The evaluation results of the anisotropic optical films of the embodiments of the present invention are shown in Table 2. In addition, FIG. 6 shows a graph of an optical profile in which the diffusion widths of the anisotropic optical films of Example 1 and Comparative Example 1 are listed.

[0275]

[0276] From Examples 1 to 16 of Table 2, it was confirmed that the anisotropic optical film of the present invention has excellent diffusivity.

[0277] Examples 1 to 3 use a benzoquinone-based component (D), and as the amount of component (D) added decreases, the difference in diffusion width decreases, but all have excellent diffusivity, and in particular, even in Example 3, where the content of component (D) is 0.006 parts by weight, an anisotropic optical film with excellent diffusion performance could be obtained.

[0278] In addition, the optical profiles of Example 1, which has the largest difference in diffusion width and also the widest diffusion width among Examples 1 to 3, and Comparative Example 1, which does not contain component (D) compared to Example 1, are shown in FIG. 6. From FIG. 6, it was confirmed that the anisotropic optical film of the present invention clearly increases the diffusion width compared to when component (D) is not included in the composition.

[0279] Examples 4 and 5 also used a benzoquinone-based component (D), and as the amount of component (D) added decreased, the difference in diffusion width decreased, but all had excellent diffusivity, and in particular, Example 4 was able to obtain an anisotropic optical film with very excellent diffusivity.

[0280] Examples 6 and 7 used a hydroquinone-based (D) component, and both had excellent diffusivity, and in particular, Example 7 was able to obtain an anisotropic optical film with very excellent diffusivity.

[0281] Example 8 used a quinone-based (D) component and was able to obtain an anisotropic optical film with excellent diffusivity.

[0282] Examples 9 to 11 have different aspect ratios of anisotropic optical films compared to Example 1, but even when the aspect ratio is changed, Examples 9 to 11 of the present invention all have excellent diffusivity, and in particular, Examples 9 and 10 were able to obtain anisotropic optical films having very excellent diffusivity.

[0283] Example 12 used a component (A) with a different type and refractive index compared to Example 1, but was able to obtain an anisotropic optical film with excellent diffusivity.

[0284] Examples 13 and 15 used component (B) of a copolymer with different refractive index and (meth)acrylate content compared to Example 1, but were able to obtain anisotropic optical films with excellent diffusivity.

[0285] Example 14 used component (B) of a thermoplastic polymer with a different type and refractive index compared to Example 1, but was able to obtain an anisotropic optical film with excellent diffusivity.

[0286] Example 16 was able to obtain an anisotropic optical film with excellent diffusivity, even though it did not contain component (B) compared to Example 1.

[0287] From the evaluation results of the examples, it was found that the composition for an anisotropic optical film of the present invention, when photocured to form an anisotropic optical film, can be made into an anisotropic optical film having excellent diffusion performance with a wide diffusion width.

[0288] Although suitable embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the forms described above. That is, it is understood that different forms or various modifications that a person skilled in the art may conceive within the scope of the invention as described in the claims are also within the technical scope of the present invention. Explanation of the symbols

[0289] 1 Uncured resin composition layer 10 light sources 11, 12 Directional Diffusion Elements LA Jang-gyeong SA Short-angle A parallel ray Light having B1, B2 directionality

Claims

Claim 1 A composition for an anisotropic optical film comprising a (meth)acrylic acid ester having a refractive index nA of 1.50 to 1.65 and having one or more aromatic rings and (meth)acryloyl groups as a component, a polymerization initiator as a component, and a polymerization inhibitor having a structure in which a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound as a component (D), wherein, in the above components, the content of the (C) component is 0.1 to 20 parts by weight per 100 parts by weight of the non-volatile component of the composition, the content of the (D) component is 0.001 to 1 part by weight per 100 parts by weight of the non-volatile component of the composition, and the ratio [content of (D) component / content of (C) component] in the composition is 0.005 to 0.

1. Claim 2 A composition for an anisotropic optical film according to claim 1, wherein the constituent component comprises, as component (B), a refractive index nB of 1.35 to 1.54, and further comprises a component in which the refractive index nB is smaller than the refractive index nA. Claim 3 A composition for an anisotropic optical film according to claim 2, wherein the (B) component is a copolymer having a content of (meth)acrylic acid ester in the constituent monomers of 10% to 80% by weight, and wherein the content of the (B) component in the constituent components is 10% to 400% by weight with respect to 100% by weight of the content of the (A) component. Claim 4 A composition for an anisotropic optical film according to claim 1, wherein the (D) component is one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6). [Chemical Formula 1] (In formulas (D1) to (D6), R1 to R5 are each independently a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 alkoxy group or an alkyl group.) Claim 5 A composition for an anisotropic optical film according to claim 2, wherein the component (B) is a thermoplastic polymer having a weight average molecular weight of 1,000 to 500,000 and a glass transition temperature of -40°C or higher. Claim 6 A composition for an anisotropic optical film according to claim 2, wherein the component (B) is a urethane (meth)acrylic acid ester comprising a cyclic aliphatic compound having two isocyanate groups and a weight average molecular weight of 3,000 to 20,000, polyalkylene glycol, and a hydroxyalkyl (meth)acrylic acid ester. Claim 7 An anisotropic optical film that is a cured product of a composition for an anisotropic optical film according to any one of claims 1 to 6, wherein the linear transmittance, which is the ratio of the amount of transmitted light in the straight direction of the incident light to the amount of incident light, changes according to the angle of incidence of light, wherein the anisotropic optical film has a matrix region and a plurality of columnar regions with a refractive index different from that of the matrix region, wherein the columnar regions are oriented and also arranged in a continuous manner from one surface of the anisotropic optical film to the other surface, and wherein the aspect ratio, which is the average major axis to the average minor axis of the columnar regions on the surface of the anisotropic optical film, is 1 to 50. Claim 8 An anisotropic optical film according to claim 7, characterized in that the aspect ratio is 2 to 20. Claim 9 An anisotropic optical film according to claim 7, characterized in that the thickness of the anisotropic optical film is 10 μm to 200 μm.

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