Composition for anisotropic optical film and anisotropic optical film

Abstract

The present invention provides a composition for anisotropic optical films, said composition being capable of producing an anisotropic optical film that is capable of achieving good diffusibility, while being excellent in terms of the enlargement of the field of view if used in a display device. A composition for anisotropic optical films, said composition being characterized by containing (A) a (meth)acrylic acid ester that has a refractive index nA of from 1.50 to 1.65, while comprising one or more aromatic rings and one or more (meth)acryloyl groups, (C) a polymerization initiator and (D) a polymerization inhibitor that has a structure wherein a carbonyl group or a hydroxyl group is added as a substituent of a conjugated cyclic compound, while being also characterized in that: the content of the component (C) relative to 100 parts by weight of the nonvolatile component in the composition is from 0.1 part by weight to 20 parts by weight; and the content of the component (D) relative to 100 parts by weight of the nonvolatile component in the composition is from 0.001 part by weight to 1 part by weight.

Description

[Technical Field]

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

[0002] BACKGROUND ART In various display devices such as liquid crystal display devices (LCDs) and organic electroluminescence devices (organic ELs), an anisotropic light diffusing layer is sometimes applied for the purpose of widening the viewing angle.

[0003] As such a light diffusion layer, Patent Document 1 discloses a light control plate obtained by irradiating a raw material composition containing a high refractive index material and a low refractive index material with ultraviolet light to cure it.

[0004] Furthermore, Patent Document 2, which is a further application, discloses a light diffusion film obtained by curing a raw material composition containing, as a high refractive index material, a (meth)acrylic acid ester compound having an aromatic skeleton, and, as a low refractive index material, a urethane (meth)acrylate compound containing a specific polyol compound and a polyisocyanate compound. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3211381 [Patent Document 2] Patent No. 6414883 Summary of the Invention [Problem to be solved by the invention]

[0006] The light diffusion layers produced from the raw material compositions disclosed in Patent Documents 1 and 2 can widen the diffusion width of the primary scattering of light to some extent, but do not provide a sufficiently wide diffusion width, and the widening of the viewing angle when used in a display device is also insufficient.

[0007] Therefore, an object of the present invention is to provide a composition for an anisotropic optical film that can provide good diffusibility and can produce an anisotropic optical film that is excellent in widening the viewing angle when used in a display device. [Means for solving the problem]

[0008] The present inventors have conducted extensive research and found that the above-mentioned problems can be solved by using a predetermined (meth)acrylate as a base resin component and blending predetermined components, thereby completing the present invention.

[0009] The present invention provides As the component (A), a (meth)acrylic acid ester having a refractive index nA of 1.50 to 1.65 and having an aromatic ring and one or more (meth)acryloyl groups; As component (C), a polymerization initiator; As a component (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; A composition for an anisotropic optical film comprising components comprising: In the above components, the content of the component (C) is 0.1 to 20 parts by weight based on 100 parts by weight of the nonvolatile components of the composition, The content of the component (D) is 0.001 to 1 part by weight based on 100 parts by weight of the nonvolatile components of the composition. A composition for an anisotropic optical film, comprising:

[0010] The constituent components may further include, as component (B), a component having a refractive index nB of 1.35 to 1.54, and the refractive index nB being smaller than the refractive index nA. The component (B) may be a copolymer in which the content of (meth)acrylic acid ester in the constituent monomers is 10% by weight to 80% by weight, In the above components, The content of the component (B) may be 10 parts by weight to 400 parts by weight relative to 100 parts by weight of the component (A). The component (D) may be one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6). [ka] (In formulas (D1) to (D6), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 alkoxy or alkyl group.) The 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. The component (B) may be a urethane (meth)acrylate ester having a weight average molecular weight of 3,000 to 20,000 and comprising a cyclic aliphatic compound having two isocyanate groups, a polyalkylene glycol, and a hydroxyalkyl (meth)acrylate ester.

[0011] The present invention also provides An anisotropic optical film which is a cured product of the composition for an anisotropic optical film, and whose linear transmittance, which is the ratio of the amount of transmitted light in a linear direction of incident light to the amount of incident light, changes depending on the incident angle of light, the anisotropic optical film has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region; the columnar regions are configured to be oriented and extend from one surface to the other surface of the anisotropic optical film, The anisotropic optical film may be an anisotropic optical film in which the aspect ratio (average major axis / average minor axis) of the columnar regions on the surface of the anisotropic optical film is 1-50.

[0012] The aspect ratio may be 2-20. The anisotropic optical film may have a thickness of 10 μm to 200 μm. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a composition for an anisotropic optical film, which can produce an anisotropic optical film that has good diffusibility and is excellent in widening the viewing angle when used in a display device. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating an example of an anisotropic optical film. [Figure 2] FIG. 2 is a top view showing the surface structure of an anisotropic optical film. [Figure 3] 1 is a three-dimensional polar coordinate representation for explaining the central axis of scattering in an anisotropic optical film. [Figure 4] FIG. 1 is a schematic diagram showing a method for measuring the diffusion performance of an anisotropic optical film. [Figure 5] FIG. 2 is a schematic diagram showing a method for producing an anisotropic optical film according to the present invention, including optional steps 1-3. [Figure 6] 1 is a graph of optical profiles showing the diffusion widths of the anisotropic optical films of Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 (an anisotropic optical film that is a cured product of the composition for an anisotropic optical film) will be described. The composition for an anisotropic optical film is a composition used to produce an anisotropic optical film.

[0016] In the following description, when an upper limit value and a lower limit value are separately described, all combinations of the upper limit value and the lower limit value are considered to be described in this specification.

[0017] In the present invention, the refractive index of each component is measured by a method in accordance with JIS K0062.

[0018] <<<<<Composition for anisotropic optical films>>>> <<<Ingredients>>> The composition for anisotropic optical films comprises constituent components including component (A) which is a (meth)acrylic acid ester, component (C) which is a polymerization initiator, and component (D) which is a polymerization inhibitor. The constituent components of the composition for anisotropic optical films preferably include component (B) which is a low refractive index material. The scope of the present invention also includes slight reactions between the constituent components during storage of the composition for anisotropic optical films.

[0019] <<Component (A): (Meth)acrylic acid ester>> The component (A) must be a (meth)acrylic acid ester with a high refractive index. 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.

[0020] By adjusting the refractive index of the component (A) to fall within this range, an anisotropic optical film with excellent diffusibility can be produced.

[0021] The component (A) is a (meth)acrylic acid ester having an aromatic ring and one or more (meth)acryloyl groups.

[0022] The number of (meth)acryloyl groups contained in component (A) is not particularly limited, but can be 1 or 2 or more, and there is no particular upper limit, but it is preferably 8 or less.

[0023] The component (A) preferably has multiple aromatic rings. The structure containing multiple aromatic rings preferably has a biphenyl ring structure and / or a diphenyl ether structure. The skeleton may contain only one such biphenyl structure or diphenyl ether structure, or two or more such structures. The presence of such a structure results in a (meth)acrylic acid ester with a very high refractive index.

[0024] Component (A) is not particularly limited, but examples thereof include biphenyl compounds represented by the following general formula (1) and diphenyl ether compounds represented by the following general formula (2).

[0025] [ka]

[0026] [ka]

[0027] In general formula (1), R 1 ~R 10 are independent of each other, and R 1 ~R 10 Any one of the above is a substituent represented by the following general formula (3) or (4): The rest may be any group so long as it does not contain a (meth)acryloyl group, and specific examples of the substituent include a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom. In addition, in the general formula (2), R 11 ~R 20 are independent of each other, and R 11 ~R 20 Any one of the above is a substituent represented by the following general formula (3) or (4): The rest may be any group so long as it does not contain a (meth)acryloyl group, and specific examples of the substituent include a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom.

[0028] [ka] (In general formula (3), R 21 is a hydrogen atom or a methyl group, n is an integer of 1 to 4, and the repeating number m is an integer of 1 to 10.

[0029] [ka] (In general formula (4), R 22 is a hydrogen atom or a methyl group, n is an integer of 1 to 4, and the repeating number m is an integer of 1 to 10.

[0030] The repeat number m in the substituents represented by the above general formulas (3) and (4) is usually preferably an integer of 1 to 10, more preferably an integer of 1 to 4, and even more preferably an integer of 1 to 2. Similarly, n in the substituents represented by general formulas (3) and (4) is usually preferably an integer of 1 to 4, and more preferably an integer of 1 or 2.

[0031] A specific example of the biphenyl compound represented by the above general formula (1) is preferably a compound represented by the following formula (5). [ka]

[0032] 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).

[0033] [ka]

[0034] The component (A) may contain only one of the above-mentioned components, or may contain multiple components.

[0035] <<(B) Component>> Component (B) is a low refractive index material that has a relatively low refractive index, and specifically, the refractive index nB of component (B) is 1.35 to 1.54, preferably 1.35 or more and less than 1.50, more preferably 1.40 or more and less than 1.50, and particularly preferably 1.45 or more 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).

[0036] The difference (nA-nB) between the refractive index nA of the component (A) and the refractive index nB of the component (B) is preferably 0.01 to 0.3, more preferably 0.03 to 0.3, and particularly preferably 0.05 to 0.3.

[0037] The component (B) is not particularly limited as long as it satisfies the above refractive index, and known resin materials can be used, such as acrylic resins, styrene resins, styrene-acrylic copolymers, polyurethane resins, polyester resins, epoxy resins, cellulose-based resins, silicone-based resins, vinyl acetate-based resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, polyvinyl alcohol resins, polyvinyl formal resins, polyvinyl acetal resins, and polyvinylidene fluoride. The component (B) is preferably a copolymer, and more preferably an acrylic copolymer. In this case, the content of (meth)acrylic acid ester in the constituent monomers is more preferably 10% by weight to 80% by weight.

[0038] The (B) component is preferably a urethane (meth)acrylate 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)acrylate ester.

[0039] Examples of cycloaliphatic compounds having two isocyanate groups include alicyclic polyisocyanates such as isophorone diisocyanate (IPDI) and hydrogenated diphenylmethane diisocyanate.

[0040] Examples of the polyol compound include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyhexylene glycol, with polypropylene glycol being preferred.

[0041] Examples of hydroxyalkyl(meth)acrylate esters include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.

[0042] The component (B) can be produced by synthesizing the above-mentioned components according to a conventional method.

[0043] The blending ratio of each component is not particularly limited, but for example, it is preferable that the molar ratio of "alicyclic compound having two isocyanate groups":"polyol compound":"hydroxyalkyl (meth)acrylic acid ester" is 1-5:1:1-5.

[0044] Component (B) is preferably a thermoplastic polymer. The glass transition temperature of component (B) is preferably −40° C. or higher, more preferably 0° C. or higher, and particularly preferably 30° C. or higher. There are no particular limitations on the upper limit of the glass transition temperature, but it is preferably 150° C. or lower, for example.

[0045] The glass transition temperature can be measured by a known method, for example, a method in accordance with JIS K7121-1987 "Method for measuring the glass transition temperature of plastics."

[0046] The weight average molecular weight of the component (B) is preferably 1,000 to 500,000, more preferably 2,000 to 50,000, and even more preferably 3,000 to 20,000.

[0047] The weight average molecular weight can be measured by a known method, for example, by the GPC method as a polystyrene-equivalent molecular weight.

[0048] By setting the glass transition temperature and weight average molecular weight of component (B) within the above ranges, compatibility with component (A) can be improved, resulting in an anisotropic optical film with excellent performance, such as improved durability in heat resistance tests and providing the anisotropic optical film with an appropriate elastic modulus before UV curing, enabling storage in a roll.

[0049] Component (B) may contain only one or more of the above-mentioned components. When component (B) is made up of multiple components, the refractive index of component (B) may be the average value of the components.

[0050] <<(C) component>> The component (C) is a polymerization initiator.

[0051] The polymerization initiator of the component (C) is a compound that generates radical species when irradiated with active energy rays such as ultraviolet rays, and any known polymerization initiator can be used.

[0052] Examples of the polymerization initiator include benzophenone, benzil, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzil dimethyl ketal, 2,2-dimethoxy-1,2-diphenylethan-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(cyclopentadienyl)-bis[2,6-difluoro-3-(pyr-1-yl)phenyl]titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like.

[0053] These compounds may be used alone or in combination.

[0054] The polymerization initiator may be used by dissolving the powder directly in the polymerizable compound, but if the solubility is poor, the polymerization initiator may be used by dissolving it in a solvent in advance.

[0055] <<(D) component>> Component (D) 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.

[0056] Examples of the polymerization inhibitor having the above structure include so-called quinone-based and phenol-based polymerization inhibitors.

[0057] Specifically, the component (D) is preferably one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6). [ka]

[0058] In formulas (D1) to (D6), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 (preferably C1 to C3) alkoxy group (e.g., a methoxy group, an ethoxy group, or a propyloxy group) or alkyl group (e.g., a methyl group, an ethyl group, a propyl group, or a tert-butyl group).

[0059] Thus, the component (D) is preferably a hydroquinone-based (e.g., the above formula (D1)), quinone methide-based (e.g., the above formulas (D2) and (D4)), benzoquinone-based (e.g., the above formula (D3)), phenol-based (e.g., the above formula (D5)), or catechol-based (e.g., the above formula (D6)) polymerization inhibitor. The component (D) is more preferably a hydroquinone-based, quinone methide-based, or benzoquinone-based polymerization inhibitor, and particularly preferably a benzoquinone-based polymerization inhibitor.

[0060] The polymerization inhibitor may have a structure to which a carbonyl group or a hydroxyl group is added, and therefore, in addition to the above formulas (D1) to (D6), pyrogallol-based and naphthoquinone-based polymerization inhibitors may also be used.

[0061] In a composition for anisotropic optical films containing a high refractive index material (A) component and a polymerization initiator, the addition of a specific polymerization inhibitor further ensures appropriate growth of the structural region described below, thereby improving the optical properties (particularly, the diffusion width).

[0062] <<Other ingredients>> As other components, various known dyes and sensitizers for improving photopolymerization properties, other known additives, etc. may be contained, and solvents, dispersion media, etc. may also be contained.

[0063] Furthermore, a thermosetting initiator capable of curing the photopolymerizable compound by heating can be used in combination with the photopolymerization initiator. In this case, heating after photocuring is expected to further promote and complete the polymerization and curing of the photopolymerizable compound.

[0064] Examples of solvents that can be used when preparing a composition containing a photopolymerizable compound include ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, and xylene.

[0065] If the acid generator used as a cationic polymerization initiator remains after the composition is cured, it may cause problems with other components when used in devices such as displays. Therefore, it is preferable that the composition does not contain an acid generator as another component. For example, it is preferable that the content of the acid generator in the composition is 1% or less.

[0066] <<<Content of each ingredient>>> <<Component (A)>> The content of component (A) relative to the total solid content of the composition (total amount of nonvolatile components excluding volatile solvents) is not particularly limited, but is preferably 30% by weight or more, 35% by weight or more, 40% by weight or more, or 45% by weight or more. The upper limit is not particularly limited, but is, for example, 99% by weight, 95% by weight, 90% by weight, 85% by weight, 80% by weight, 70% by weight, or 60% by weight.

[0067] <<(B) Component>> The content of component (B) in the composition is preferably 10 to 400 parts by weight, more preferably 25 to 200 parts by weight, and particularly preferably 50 to 100 parts by weight, when the content of component (A) is 100 parts by weight. From another perspective, the content of component (B) relative to the total amount of nonvolatile components of the composition (excluding solvents and dispersion media) is preferably 10 to 80% by weight, more preferably 15 to 70% by weight, and even more preferably 20 to 60% by weight.

[0068] <<(C) component>> The content of component (C) in the composition is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, and particularly preferably 1 to 10 parts by weight, when the amount of non-volatile components in the composition is 100 parts by weight. From another perspective, the content of component (C) relative to the total amount of nonvolatile 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.

[0069] <<(D) component>> The content of component (D) in the composition is preferably 0.001 to 1 part 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, when the amount of non-volatile components in the composition is 100 parts by weight. From another perspective, the content of component (D) in the composition relative to the total amount of nonvolatile components of the composition is preferably 0.001% by weight to 0.5% by weight, more preferably 0.005% by weight to 0.1% by weight, and particularly preferably 0.01% by weight to 0.04% by weight.

[0070] In the composition, the ratio of [content of component (D) / content of component (C)] is preferably 0.005 to 0.1, and more preferably 0.01 to 0.05.

[0071] The composition for an anisotropic optical film according to the present invention can provide an anisotropic optical film having excellent diffusibility by adjusting the content of each component within the above ranges.

[0072] <<<<<Anisotropic Optical Film>>>> Next, preferred examples of anisotropic optical films obtained using the composition for anisotropic optical films will be described. Note that, by using the composition for anisotropic optical films, it is also possible to produce anisotropic optical films other than the anisotropic optical films shown below.

[0073] An "anisotropic optical film" is an anisotropic optical film whose diffusion, transmission, and diffusion distribution of light change depending on the angle of incidence of light, and has anisotropy and directionality that depend on the angle of incidence of light. Therefore, it is different from directional diffusion films, isotropic diffusion films, and diffusion films that are oriented in a specific direction, which are not dependent on the angle of incidence of light. In the case of anisotropic optical films, the linear transmittance [percentage of (amount of transmitted light in the linear direction of incident light) / (amount of incident light)] changes depending on the angle of incident light. That is, for light incident on anisotropic optical films, incident light within a certain angle range is mainly transmitted because of its increased linearity, while incident light within other angle ranges is mainly diffused because of its increased diffusibility.

[0074] <<<Structure>>> The anisotropic optical film of the present invention has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region. The "matrix region" and "multiple columnar regions" in the anisotropic optical film are regions formed by the difference in local refractive index of the material constituting the anisotropic optical film according to the present invention, and are relative regions that indicate whether the refractive index is lower or higher than that of the other region. These regions are formed by phase separation when the material constituting the anisotropic optical film is cured. That is, the difference in refractive index is not particularly limited as long as it is such that at least a part of the light incident on the anisotropic optical film is reflected at the interface between the matrix region and the columnar region. The plurality of columnar regions contained in the anisotropic optical film are usually configured to be oriented and extend from one surface of the anisotropic optical film to the other surface (see FIG. 1).

[0075] <<Columnar area>> The length of the columnar region is not particularly limited, and may penetrate from one surface to the other surface of the anisotropic optical film, or may be of a length that does not reach from one surface to the other surface.

[0076] The surface shape of the plurality of columnar regions of the anisotropic optical film can have a minor axis and a major axis.

[0077] The surface shape of the columnar region is not particularly limited and can be, for example, circular, elliptical, or polygonal. In the case of a circle, the minor axis and the major axis are equal. In the case of an ellipse, the minor axis is the length of the minor axis, and the major axis is the length of the major axis. In the case of a polygon, the shortest length connecting two points on the polygon's outer periphery within the polygon can be taken as the minor axis, and the longest length can be taken as the major axis. Figure 2 shows the columnar region as viewed from the surface direction of the anisotropic optical film. In Figure 2, LA represents the major axis, and SA represents the minor axis.

[0078] The minor axis and major axis of the columnar region can be determined by observing the surface of the anisotropic optical film with an optical microscope, measuring the minor axis and major axis of each of 20 arbitrarily selected columnar regions, and averaging these values.

[0079] The ratio of the average major axis to the average minor axis of the columnar regions (average major axis / average minor axis), ie, the aspect ratio, is not particularly limited, but is preferably 1-50, for example, and more preferably 2-20.

[0080] FIG. 2(a) shows an anisotropic optical film in which the aspect ratio of the columnar regions is 2 to 50, and FIG. 2(b) shows an anisotropic optical film in which the aspect ratio of the columnar regions is 1 or more and less than 2.

[0081] When the aspect ratio is 1 or more and less than 2, if light parallel to the column axis direction of the columnar region is irradiated, the transmitted light is diffused isotropically (see Figure 1(a)). On the other hand, if the aspect ratio is 2 to 50, if light parallel to the column axis direction is irradiated, the transmitted light is diffused anisotropically according to the aspect ratio (see Figure 1(b)).

[0082] In the case where the aspect ratio is 2 to 50, when the aspect ratio is in the range of more than 20 but not more than 50, more anisotropic diffusion is achieved, while when the aspect ratio is in the range of 2 to 20, the film has intermediate properties between an aspect ratio of 1 or more but less than 2 and an aspect ratio of more than 20 but not more than 50. In this way, by dividing the aspect ratio range into 1 or more but less than 2, 2 to 20, and more than 20 but not more than 50, anisotropic optical films having respectively different optical properties can be obtained. The composition for anisotropic optical films according to the present invention can be used as a preferred raw material in the production of anisotropic optical films having any aspect ratio.

[0083] The anisotropic optical film may include a plurality of columnar regions having one aspect ratio, or may include a plurality of columnar regions having different aspect ratios.

[0084] <<<Scattering center axis>>> The "central scattering axis" of an anisotropic optical film means the direction that coincides with the angle of incident light of light at which the light diffusion properties are approximately symmetrical across the angle of incident light when the angle of incident light to the anisotropic optical film is changed. The reason for the term "approximately symmetrical" is that when the central scattering axis is inclined with respect to the normal direction of the film (thickness direction of the film), the optical profile (described later) relating to the light diffusion properties does not strictly have symmetry. Here, the scattering central axis and the orientation direction (extension direction) of the columnar region are usually parallel to each other. Note that the scattering central axis and the orientation direction of the columnar region being parallel to each other only needs to satisfy the law of refractive index (Snell's law), and do not necessarily need to be strictly parallel. The scattering central axis can be confirmed by observing the column axis inclination of the columnar regions in the cross section of the anisotropic optical film using an optical microscope, by observing the projection shape of light passing through the anisotropic optical film while changing the angle of incident light, or by an optical profile.

[0085] Snell's law states that when light is incident on the interface between a medium with a refractive index n1 and a medium with a refractive index n2, the relationship n1 sin θ1 = n2 sin θ2 holds between the incident light angle θ1 and the refraction angle θ2. For example, if n1 = 1 (air) and n2 = 1.51 (anisotropic optical film), when the incident light angle is 30°, the orientation direction (refraction angle) of the columnar region is approximately 19°. Even if the incident light angle and the refraction angle differ in this way, as long as they satisfy Snell's law, they are included in the concept of parallelism in the present invention.

[0086] As described above, the scattering central axis refers to the direction that coincides with the incident light angle of light at which the light diffusion properties are approximately symmetrical across the incident light angle when the incident light angle to the anisotropic optical film is changed. Note that the scattering central axis in this case can be determined by calculating the linear transmittance of light depending on the incident light angle to the anisotropic optical film, creating an optical profile that is a graph showing the relationship, and then determining the incident light angle (the center of the diffusion region, approximately 17° in the case of Example 1 in Figure 6) at the approximately central part sandwiched between the minimum values ​​of linear transmittance in this optical profile (as an example, Figure 6 showing the optical profile in the Examples).

[0087] Although the optical profile does not directly express light diffusion, if we interpret it as meaning that a decrease in linear transmittance results in an increase in diffuse transmittance, it can be said that it generally indicates light diffusion.

[0088] As shown in FIG. 6, the incident light angle range between the two minimum values ​​of the maximum linear transmittance is called the "diffusion region," and the other incident light angle range is called the "non-diffusion region." Furthermore, in the present invention, the diffusion region is referred to as the "diffusion width."

[0089] Next, the scattering central axis P in the anisotropic optical film will be described from another perspective with reference to Fig. 3. Fig. 3 is a three-dimensional polar coordinate representation for explaining the scattering central axis P in the anisotropic optical film.

[0090] In a three-dimensional polar coordinate representation as shown in Fig. 3, the scattering central axis can be expressed by a polar angle θ and an azimuthal angle φ, 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. In other words, Pxy in Fig. 3 can be said to be the length direction of the scattering central axis projected onto the surface of the anisotropic optical film.

[0091] Here, the polar angle θ (−90°<θ<90°) between the normal to the anisotropic optical film (the z-axis shown in FIG. 3) and the columnar regions can be defined as the scattering central axis angle. In the step of photocuring the uncured resin composition layer to form columnar regions, the angle of the columnar axis direction of the columnar regions can be adjusted within a desired range by changing the direction of the irradiated light beam.

[0092] <<<Thickness>>> 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.

[0093] <<<<<Manufacturing method for anisotropic optical films>>>> Next, a method for producing an anisotropic optical film using the composition for an anisotropic optical film will be described.

[0094] First, a composition for an anisotropic optical film (hereinafter sometimes referred to as a "photocurable resin composition") is applied to a suitable substrate such as a transparent PET film to form a sheet, which is then dried as necessary to volatilize the solvent to form an uncured resin composition layer. An anisotropic optical film can be produced by irradiating this uncured resin composition layer with light.

[0095] More specifically, the process for forming an anisotropic optical film mainly includes the following steps. (1) Step 1-1: Step of Providing an Uncured Resin Composition Layer on a Substrate (2) Step 1-2: Obtaining parallel light from a light source (3) Optional Step 1-3: Step of Obtaining a Directed Light Beam (4) Step 1-4: Step of curing the uncured resin composition layer

[0096] <<<Step 1-1: Step of Providing an Uncured Resin Composition Layer on a Substrate>>> The photocurable resin composition can be applied to a substrate in the form of a sheet as an uncured resin composition layer by conventional coating or printing methods. Specifically, coating methods 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, calendar coating, dam coating, dip coating, and die coating, as well as printing methods such as intaglio printing (e.g., gravure printing) and stencil printing (e.g., screen printing), can be used. When the composition has a low viscosity, a dam of a certain height can be provided around the substrate, and the composition can be cast into the space surrounded by the dam.

[0097] In step 1-1, in order to prevent oxygen inhibition of the uncured resin composition layer and efficiently form the columnar regions that are characteristic of anisotropic optical films, it is also possible to laminate a mask that adheres closely to the light-irradiated side of the uncured resin composition layer and locally changes the light irradiation intensity.

[0098] The mask material is preferably one in which a light-absorbing filler such as carbon is dispersed in a matrix, so that part of the incident light is absorbed by the carbon but the openings allow sufficient light to pass through. Such a matrix may be a transparent plastic such as PET, TAC, PVAc, PVA, acrylic, or polyethylene, or an inorganic material such as glass or quartz, or a sheet containing such a matrix and patterned to control the amount of UV light transmitted or containing a pigment that absorbs UV light.

[0099] When 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 normal transparent film on the uncured resin composition layer is also effective in preventing oxygen inhibition and promoting the formation of columnar regions. Light irradiation through such a mask or transparent film induces a photopolymerization reaction in the composition containing the photopolymerizable compound according to the irradiation intensity, which easily generates a refractive index distribution, and is effective for producing the anisotropic optical film according to this embodiment.

[0100] <<Step 1-2: Obtaining parallel light from the light source>> As the light source, a short-arc ultraviolet light source is usually used, and specifically, a high-pressure mercury lamp, a low-pressure mercury lamp, a metahalide lamp, a xenon lamp, etc. It is necessary to obtain light rays parallel to the desired scattering central axis, and such parallel light rays can be obtained, for example, by arranging a point light source and arranging an optical lens such as a Fresnel lens between this point light source and the uncured resin composition layer to irradiate parallel light rays, or by arranging a reflecting mirror behind the light source so that light is emitted as a point light source in a predetermined direction.

[0101] <<<Optional Step 1-3: Step of Obtaining a Directed Light Beam>>> Optional step 1-3 is a step of making parallel light incident on a directional diffusion element to obtain a directional light beam. Figure 5 is a schematic diagram showing a method for producing an anisotropic optical film according to the present invention, including optional step 1-3.

[0102] The directional diffusion elements 11 and 12 used in the optional steps 1-3 may be any elements that can impart directionality to the parallel light beam A incident from the light source 10.

[0103] 5 shows that directional light (B1 or B2) is incident on the uncured resin composition layer 1 in a manner that causes a large amount of diffusion in the x direction and almost no diffusion in the y direction. To obtain such directional light, for example, a method can be adopted in which needle-shaped fillers with a high aspect ratio are contained in the directional diffusion elements 11 and 12 and the needle-shaped fillers are oriented so that their major axes extend in the y direction. The directional diffusion elements 11 and 12 can be formed using various methods other than the method using needle-shaped fillers.

[0104] Here, the aspect ratio of the directional light is preferably set to 2 to 50. A columnar region having an aspect ratio that roughly corresponds to this aspect ratio is formed.

[0105] In optional step 1-3, the size (aspect ratio, minor axis SA, major axis LA, etc.) of the columnar regions to be formed can be appropriately determined by adjusting the spread of the directional light. For example, the anisotropic optical film of this embodiment can be obtained in either (a) or (b) of Figure 5. The difference between (a) and (b) of Figure 5 is that the spread of the directional light is large in (a) (B1) and small in (b) (B2). The size of the columnar regions differs depending on the size of the spread of the directional light.

[0106] The spread of directional light mainly depends on the type of directional diffusion elements 11 and 12 and the distance from the uncured resin composition layer 1. As the distance decreases, the size of the columnar region decreases, and as the distance increases, the size of the columnar region increases. Therefore, the size of the columnar region can be adjusted by adjusting the distance.

[0107] <<<Step 1-4: Step of curing the uncured resin composition layer>>> The light irradiated onto the uncured resin composition layer to cure the uncured resin composition layer must contain a wavelength capable of curing the photopolymerizable compound, and light from a mercury lamp with a wavelength centered at 365 nm is usually used. When this wavelength band is used to produce an anisotropic optical film, the illuminance is 0.01 mW / cm. 2 ~100mW / cm 2 The range of 0.1 mW / cm is preferred. 2 ~20mW / cm 2 It is more preferable that the illuminance is 0.01 mW / cm 2 If the power is less than 100mW / cm, it will take a long time to cure, resulting in poor production efficiency. 2 If the curing time exceeds this limit, the photopolymerizable compound will cure too quickly, resulting in no structure formation and making it impossible to achieve the desired optical properties.

[0108] The light irradiation time is not particularly limited, but is preferably 10 to 180 seconds, more preferably 30 to 120 seconds. By irradiating with the light beam, the anisotropic optical film of this embodiment can be obtained.

[0109] As described above, an anisotropic optical film is obtained by forming a specific internal structure in the uncured resin composition layer through irradiation with low-intensity light for a relatively long period of time. Therefore, such light irradiation alone may leave unreacted monomer components, causing stickiness and problems with handling and durability. In such cases, a low-intensity light of 1000 mW / cm is used. 2 The remaining monomer can be polymerized by additionally irradiating the film with light of such high intensity. The light irradiation may be performed from the side opposite to the side where the mask is laminated.

[0110] As described above, when curing the uncured resin composition layer, the scattering central axis of the resulting anisotropic optical film can be made as desired by adjusting the angle of light irradiated onto the uncured resin composition layer.

[0111] The anisotropic optical film may further have other layers (adhesive layer, functional layer, transparent film layer, etc.).

[0112] <<<<<Applications of Anisotropic Optical Films>>>> Because anisotropic optical films have an excellent effect of improving viewing angle dependence, they can be applied to all kinds of display devices, such as liquid crystal display devices, organic EL display devices, and plasma displays. Furthermore, when used in reflective liquid crystal display devices, anisotropic optical films are expected to have the effect of increasing the reflected brightness in a specific direction. In addition, anisotropic optical films can also be applied to lighting fixtures, building materials, and the like. [Example]

[0113] Next, the present invention will be explained in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0114] (Manufacturing of anisotropic optical films) The anisotropic optical films of the present invention and comparative examples were produced according to the following method.

[0115] [Example 1] <<1. Preparation of composition solution 1 for anisotropic optical film>> The various materials shown below were mixed and stirred in the amounts shown below to obtain a composition solution 1 for an anisotropic optical film. <Component (A)> m-Phenoxybenzyl acrylate Refractive index: 1.57 55 parts by weight <(B) component> Copolymer of polymethyl methacrylate (PMMA) and polybutyl acetate (copolymer with 50% (meth)acrylate) Refractive index: 1.48 Weight average molecular weight: 37000 Glass transition temperature: -30℃ 45 parts by weight <(C) component> 2,2-Dimethoxy-2-phenylacetophenone (manufactured by IGM Resins BV, trade name: Omnirad 651) (When the amount of nonvolatile components of the composition is 100 parts by weight) 1.3 parts by weight <(D) component> 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Chemical Industry Co., Ltd., benzoquinone-based polymerization inhibitor) (When the amount of nonvolatile components of the composition is 100 parts by weight) 0.02 parts by weight <Solvent> Butyl acetate 71 parts by weight

[0116] <<2. Preparation of Composition 1 for Anisotropic Optical Film>> The obtained composition solution 1 for anisotropic light-diffusing films was applied to a 100 μm thick PET film (manufactured by Toyobo Co., Ltd., product name: A4300) using an applicator, and the coating was then dried in a clean oven with the temperature inside the drying furnace set to 80°C, thereby obtaining composition 1 for anisotropic optical films with a film thickness of 50 μm.

[0117] <<3. Preparation of Anisotropic Optical Film 1>> Next, a polyvinyl alcohol film (hereinafter referred to as a PVA mask) with carbon uniformly dispersed therein was laminated using a laminator on the surface of the composition for anisotropic optical films 1 that was not in contact with the PET film. The resulting laminate was heated to 70°C, and while the temperature was kept constant, parallel light emitted from an epi-illumination unit (manufactured by Hamamatsu Photonics, product name: L2859-01) from above the PVA mask surface was converted into linear light via a directional diffusion element that gave the light an aspect ratio of 5, and the irradiation intensity was 2 mW / cm. 2 The light was irradiated at an angle of 11.5° from the normal direction of the composition 1 for an anisotropic optical film to the direction in which the light was diffused by the directional diffusion element and the thickness direction of the composition 1 for an anisotropic optical film (hereinafter referred to as MD direction). The PVA mask and the PET film were peeled off from the resulting laminate, to obtain an anisotropic optical film 1 of Example 1.

[0118] [Example 2] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (D) was changed to 0.01 parts by weight of 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Chemical Industry Co., Ltd.), to obtain anisotropic optical film 2 of Example 2.

[0119] [Example 3] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (D) was changed to 0.006 parts by weight of 2,5-di-t-butyl-1,4-benzoquinone (DBBQ) (Tokyo Chemical Industry Co., Ltd.), to obtain anisotropic optical film 3 of Example 3.

[0120] [Example 4] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (D) was changed to 0.02 parts by weight of tetramethyl-1,4-benzoquinone (TMBQ) (Tokyo Chemical Industry Co., Ltd.), to obtain anisotropic optical film 4 of Example 4.

[0121] [Example 5] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (D) was changed to 0.01 parts by weight of tetramethyl-1,4-benzoquinone (TMBQ) (Tokyo Chemical Industry Co., Ltd.), to obtain anisotropic optical film 5 of Example 5.

[0122] [Example 6] Anisotropic optical film 6 of Example 6 was obtained in the same manner as in Example 1, except that in the formulation of Example 1, component (D) was changed to 0.01 parts by weight of methylhydroquinone (MHQ) (Tokyo Chemical Industry Co., Ltd.).

[0123] [Example 7] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (D) was changed to 0.1 parts by weight of 2,5-di-t-butyl-1,4-hydroquinone (DBHQ) (Tokyo Chemical Industry Co., Ltd.), to obtain anisotropic optical film 7 of Example 7.

[0124] [Example 8] Anisotropic optical film 8 of Example 8 was obtained in the same manner as in Example 1, except that in the formulation of Example 1, component (D) was changed to 0.06 parts by weight of Irgastab UV22 (BASF Japan Ltd.). Note that Irgastab UV22 is a mixture of para-quinone methide and ortho-quinone methide.

[0125] [Example 9] The same procedure as in Example 1 was carried out to obtain anisotropic optical film 9 of Example 9, except that when producing anisotropic optical film 1, the light was converted into a linear beam via a directional diffusion element that would give an aspect ratio of less than 2, and the heating temperature was changed to 50°C.

[0126] [Example 10] The same procedure as in Example 1 was carried out to obtain anisotropic optical film 10 of Example 10, except that when preparing anisotropic optical film 1, the light was converted into a linear beam via a directional diffusion element with an aspect ratio of 10.

[0127] [Example 11] The same procedure as in Example 1 was carried out to obtain anisotropic optical film 11 of Example 11, except that when preparing anisotropic optical film 1, the light was converted into a linear beam via a directional diffusion element with an aspect ratio of 30.

[0128] [Example 12] An anisotropic optical film 12 of Example 12 was obtained in the same manner as in Example 1, except that in the formulation of Example 1, component (A) was changed to 2-hydroxy-3-phenoxypropyl acrylate (refractive index: 1.52).

[0129] [Example 13] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (B) was changed to an acrylic block copolymer (a copolymer having 20% ​​(meth)acrylate), to obtain an anisotropic optical film 13 of Example 13. <(B) component> Refractive index: 1.44 Weight average molecular weight: 43,000 Glass transition temperature: -30℃

[0130] [Example 14] An anisotropic optical film 14 of Example 14 was obtained in the same manner as in Example 1, except that in the formulation of Example 1, the component (B) was changed to a thermoplastic polymer (polyvinyl acetate). <(B) component> Refractive index: 1.46 Average weight molecular weight: 200,000 Glass transition temperature: 40℃

[0131] [Example 15] The same procedure as in Example 1 was carried out, except that in the formulation of Example 1, component (B) was changed to a urethane (meth)acrylic acid ester (a copolymer in which the content of (meth)acrylic acid ester in the constituent monomers is 40% by weight) consisting of polypropylene glycol (PPG), isophorone diisocyanate (IPDI), and 2-hydroxyethyl methacrylate (HEMA), to obtain an anisotropic optical film 15 of Example 15. <(B) component> Refractive index: 1.46 Weight average molecular weight: 10,000

[0132] [Example 16] Anisotropic optical film 16 of Example 16 was obtained in the same manner as in Example 1, except that component (B) was omitted from the formulation of Example 1.

[0133] [Comparative Examples 1 to 16] 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 component (D) was not added.

[0134] Table 1 shows the type of component (D) for each example and the content of component (D) per 100 parts by weight of the nonvolatile components of the composition.

[0135] [Table 1]

[0136] (Evaluation method) The anisotropic optical films of the examples of the present invention and the comparative examples produced as described above were evaluated as follows.

[0137] [Evaluation of light diffusion] The light diffusion property was evaluated using the diffusion width, which was determined by the following method.

[0138] The light diffusion properties of the anisotropic optical films of the Examples and Comparative Examples were evaluated using a goniophotometer (manufactured by Genesia) capable of arbitrarily varying the projection angle of the light source and the reception angle of the detector, as shown in Fig. 4. As shown in Fig. 4, the anisotropic optical films (Sample 3) of the Examples and Comparative Examples were placed between a light source 1 and a detector 2 (here, light source 1 and detector 2 were fixed). In this evaluation, the incident angle of 0° was defined as when irradiated light I from light source 1 was incident in the normal direction of the anisotropic optical film (Sample 3), and the anisotropic optical film (Sample 3) was positioned so that it could be arbitrarily rotated around the TD direction shown in Fig. 1 as the central axis. Next, the anisotropic optical films (Sample 3) of the examples and comparative examples were rotated continuously in 1° increments within the range of -75° to 75°, and the amount of light transmitted in the linear direction (linear transmitted light amount) at each incident light angle was measured. The amount of linear transmitted light was measured by measuring wavelengths in the visible light region using a visibility filter. The ratio of the amount of linear transmitted light (amount of incident light, incident light amount) irradiated directly from the light source 1 to the amount of linear transmitted light irradiated to the detector 2 without passing through the anisotropic optical film (Sample 3) was defined as the linear transmittance (%). As a result of the above measurements, an optical profile was obtained from the obtained data, and based on this optical profile, the maximum value (maximum linear transmittance) and the minimum value (minimum linear transmittance) of the linear transmittance were determined.

[0139] In this case, the linear transmittance, which is the ratio of the linear transmitted light amount to the incident light amount of the anisotropic optical film, shows two minimum values, and the diffusion width was calculated as the angle difference between the two minimum values. In the optical profile, the normal direction of the anisotropic optical film is set to 0°, and the incident light angle is indicated as a negative or positive direction. Therefore, the incident light angle may have a negative value. Therefore, when the two incident light angle values ​​are "a positive incident light angle value and a negative incident light angle value," the diffusion width, which is the angular range of the incident light angle, is determined as "the sum of the absolute value of the negative incident light angle value and the positive incident light angle value." 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 taken as the diffusion width, which is the angular range of the incident light angles. Furthermore, when the values ​​of the two incident light angles are "both negative," the difference between the absolute values ​​of each and the smaller value is taken as the diffusion width, which is the angular range of the incident light angles.

[0140] [Measurement of the aspect ratio of the columnar region (surface observation of anisotropic light-diffusing layer)] The surfaces (the UV-irradiated side during production) of the anisotropic optical films of the Examples and Comparative Examples were observed with an optical microscope, and the major axis LA and minor axis SA of the columnar regions were measured for 20 randomly selected columnar regions. The average of the measured major axis LA and minor axis SA was calculated, and the average major axis LA / average minor axis SA was calculated as the aspect ratio of the columnar regions.

[0141] [Evaluation criteria] The difference in diffusion width between the anisotropic optical films 1 to 16 of the examples and the comparative anisotropic optical films 1 to 16 of the comparative examples, which were prepared in the same manner as the examples except that the component (D) was not added to the composition, was calculated for each example, and evaluated according to the following evaluation criteria. ◎: Excellent diffusion 10° or more 〇: Excellent diffusion 5° or more and less than 10° △: Diffusion is acceptable for practical use, 0° or more and less than 5° ×: Insufficient diffusion, less than 0°

[0142] The evaluation results of the anisotropic optical films of the examples of the present invention are shown in Table 2. Furthermore, a graph of the optical profile showing the diffusion widths of the anisotropic optical films of Example 1 and Comparative Example 1 is shown in FIG.

[0143] [Table 2]

[0144] From Examples 1 to 16 in Table 2, it was confirmed that the anisotropic optical film of the present invention has excellent diffusibility.

[0145] In Examples 1 to 3, a benzoquinone-based (D) component was used, and although the difference in diffusion width became smaller as the amount of (D) component added decreased, all of the examples had excellent diffusion properties. In particular, even in Example 3, where the content of (D) component was 0.006 parts by weight, an anisotropic optical film with excellent diffusion performance was obtained. Furthermore, Fig. 6 shows the optical profiles of Example 1, which had the largest difference in diffusion width and the widest diffusion width among Examples 1 to 3, and Comparative Example 1, which did not contain component (D) in Example 1. Fig. 6 confirms that the anisotropic optical film of the present invention has a clearly increased diffusion width compared to when the component (D) is not contained in the composition.

[0146] In Examples 4 and 5, a benzoquinone-based component (D) was also used, and although the difference in diffusion width decreased as the amount of component (D) added decreased, all of the films had excellent diffusion properties. In particular, Example 4 produced an anisotropic optical film with excellent diffusion properties.

[0147] In Examples 6 and 7, a hydroquinone-based component (D) was used, and all of them had excellent diffusibility. In particular, Example 7 was able to obtain an anisotropic optical film with very excellent diffusibility.

[0148] In Example 8, a quinone-based component (D) was used, and an anisotropic optical film with excellent diffusivity was obtained.

[0149] In Examples 9 to 11, the aspect ratio of the anisotropic optical film was different from that of Example 1. However, even when the aspect ratio was changed, Examples 9 to 11 of the present invention all had excellent diffusion properties, and in particular, Examples 9 and 10 were able to obtain anisotropic optical films with very excellent diffusion properties.

[0150] Example 12 used component (A) of a different type and refractive index from Example 1, but was able to obtain an anisotropic optical film with excellent diffusivity.

[0151] In Examples 13 and 15, copolymers (B) having different refractive indices and (meth)acrylate contents were used compared to Example 1, and anisotropic optical films with excellent diffusion properties were obtained.

[0152] In Example 14, a thermoplastic polymer (B) of a different type and refractive index was used compared to Example 1, and an anisotropic optical film with excellent diffusivity was obtained.

[0153] Unlike Example 1, Example 16 did not contain the component (B), but an anisotropic optical film with excellent diffusibility was obtained.

[0154] From the evaluation results of the examples, it was found that when the composition for an anisotropic optical film of the present invention is photocured to form an anisotropic optical film, it can be made into an anisotropic optical film with a wide diffusion width and excellent diffusion performance.

[0155] While the preferred embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the above-described embodiments. In other words, it is understood that other embodiments or various modifications that can be conceived by a person skilled in the art within the scope of the invention described in the claims also fall within the technical scope of the present invention. [Explanation of symbols]

[0156] 1 Uncured resin composition layer 10 light source 11, 12 Directional diffusion elements LA major axis SA short axis A Parallel rays B1, B2: directional light

Claims

1. As the component (A), a (meth)acrylic acid ester having a refractive index nA of 1.50 to 1.65 and having an aromatic ring and one or more (meth)acryloyl groups; As the component (C), a polymerization initiator; As the component (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; A composition for an anisotropic optical film comprising components comprising: In the above components, the content of the component (C) is 0.1 to 20 parts by weight based on 100 parts by weight of the nonvolatile components of the composition for anisotropic optical films, the content of the component (D) is 0.001 to 1 part by weight based on 100 parts by weight of the nonvolatile components of the composition for anisotropic optical films, In the composition for anisotropic optical films, the ratio of the content of component (D) to the content of component (C) is 0.005 to 0.

1. A composition for an anisotropic optical film, comprising:

2. 2. The composition for an anisotropic optical film according to claim 1, wherein the constituent components further include, as component (B), a component having a refractive index nB of 1.35 to 1.54 and the refractive index nB being smaller than the refractive index nA.

3. The component (B) is a copolymer in which the content of a (meth)acrylic acid ester in the constituent monomers is 10% by weight to 80% by weight, In the above components, The content of the component (B) is 10 to 400 parts by weight per 100 parts by weight of the component (A). The composition for an anisotropic optical film according to claim 2 .

4. The composition for an anisotropic optical film according to any one of claims 1 to 3, wherein the component (D) is one or more compounds selected from the group consisting of compounds represented by the following chemical formulas (D1) to (D6): 【Chemical 1】 (In formulas (D1) to (D6), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a carboxyl group, or a C1 to C4 alkoxy or alkyl group.)

5. The composition for an anisotropic optical film according to any one of claims 2 to 4, 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.

6. The composition for anisotropic optical films according to any one of claims 2 to 5, characterized in that the component (B) is a urethane (meth)acrylic acid ester having a weight average molecular weight of 3,000 to 20,000 and consisting of a cyclic aliphatic compound having two isocyanate groups, a polyalkylene glycol, and a hydroxyalkyl (meth)acrylic acid ester.

7. 7. An anisotropic optical film, which is a cured product of the composition for an anisotropic optical film according to any one of claims 1 to 6, and which has a linear transmittance, which is a ratio of the amount of transmitted light in a linear direction of incident light to the amount of incident light, that changes depending on the angle of incidence of light, the anisotropic optical film has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region; the columnar regions are configured to be oriented and extend from one surface to the other surface of the anisotropic optical film, An anisotropic optical film, characterized in that the columnar regions on the surface of the anisotropic optical film have an aspect ratio, which is the average major axis / average minor axis, of 1 to 50.

8. 8. The anisotropic optical film according to claim 7, wherein the aspect ratio is 2 to 20.

9. 9. The anisotropic optical film according to claim 7, wherein the thickness of the anisotropic optical film is 10 μm to 200 μm.

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