JP2013205468A - Optical anisotropy film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical anisotropy film, when being used for various types of display devices, with anisotropy improved, having a small phase difference and a little deflection resolution (leak of light).SOLUTION: The optical anisotropy film includes at least low refractive index regions and high refractive index regions inside a film. On the film surface, the low refractive index regions and the high refractive index regions are alternately aligned and, in the film cross section, the low refractive index regions and the high refractive index regions extend in the thickness direction. The optical anisotropy film is formed by curing photocurable compound monomer, oligomer, prepolymer, or macromonomer having at least silicone skeleton, and has an in-plane phase difference of 25 nm or less.

Description

  The present invention relates to an anisotropic optical film that has no wavelength dependency and can be used in various display devices and has excellent visibility.

  Members having light diffusibility are used in display devices as well as lighting fixtures and building materials. Examples of the display device include a liquid crystal display device (LCD) and an organic electroluminescence element (organic EL). As the light diffusion expression mechanism of the light diffusing member, scattering due to unevenness formed on the surface (surface scattering), scattering due to a refractive index difference between the matrix resin and fine particles dispersed therein (internal scattering), and surface scattering This is due to both internal scattering. However, these light diffusing members generally have isotropic diffusion performance, and even if the incident angle is slightly changed, the diffusion characteristics of the transmitted light are not greatly different.

  On the other hand, a light control plate (anisotropic optical film) is known in which incident light in a certain angle region is strongly diffused and incident light at other angles is transmitted (for example, Patent Document 1). This light control plate is cured by irradiating light from above the sheet-like photosensitive composition layer using a linear light source. And in the sheet-like substrate, as shown in FIG. 1 (a), the peripheral region is aligned with the length direction of the linear light source 51 disposed above the anisotropic optical film 50 when the anisotropic optical film 50 is produced. It is considered that the plate-like structures 40 having different refractive indexes are formed in parallel to each other. As shown in FIG. 2, a sample is arranged between a light source (not shown) and the light receiver 3, and the sample passes straight through the sample surface while changing the angle about the straight line L of the sample surface, and enters the light receiver 3. The rate can be measured.

  FIG. 3 shows the incident angle dependence of the scattering characteristics of the anisotropic optical film 50 shown in FIG. 1 measured using the method shown in FIG. The vertical axis indicates the linear transmittance (an amount of parallel light emitted in the same direction as the incident direction when a predetermined amount of parallel light is incident), which is an index indicating the degree of scattering, and the horizontal axis indicates the incident angle. Indicates. The solid line and the broken line in FIG. 3 respectively rotate the anisotropic optical film 50 about the AA axis (through the plate-like structure) and the BB axis (parallel to the plate-like structure) in FIG. Show the case. The sign of the incident angle indicates that the direction in which the anisotropic optical film 50 is rotated is opposite. The solid line in FIG. 3 shows that the linear transmittance remains small both in the front direction and in the oblique direction. This is because the optical film 50 is scattered regardless of the incident angle when rotated about the AA axis. It means a state. In addition, the broken line in FIG. 3 shows that the linear transmittance is small in the direction near 0 °. This is also true when the optical film is rotated with respect to the light in the front direction when rotated about the BB axis. Means that it is in a scattering state. Furthermore, the linear transmittance increases in the direction where the incident angle is large. This is because when the optical film is rotated around the BB axis, the optical film is in a transmission state with respect to light in an oblique direction. Means. Thanks to this structure, for example, although the transmissivity varies depending on the incident angle in the horizontal direction, the transmissivity does not change even if the incident angle is changed in the vertical direction. Here, as shown in FIG. 3, a curve indicating the incident angle dependence of the scattering characteristic is hereinafter referred to as an “optical profile”. The optical profile does not directly represent the scattering characteristics, but if it is interpreted that the diffuse transmittance is increased due to the decrease of the linear transmittance, the diffusion profile is generally indicated. I can say that.

  The optical characteristics of the anisotropic optical film 50 are defined by the inclination of the plate-like structure 40 with respect to the film normal. In this case, the incident light from a direction substantially parallel to the plate-like structure 40 is strongly diffused, and the incident light passing through the plate-like structure is transmitted without being diffused. It can be said.

  The anisotropic optical film 50 is in a state where the plate-like structures are aligned as described above, and the molecules present in the plate-like structure are in a state where they are easily oriented in the in-plane direction of the plate-like structure. If this is not particularly taken into consideration in the design, molecular orientation occurs, birefringence due to the orientation occurs, and the anisotropic optical film becomes a film having an in-plane retardation. When used in a display device such as an LCD, it is often undesirable to have a phase difference. For example, when this anisotropic optical film is disposed between the liquid crystal cell and the polarizing plate for the purpose of widening the viewing angle and improving the luminance, the optical system designed with the polarizing plate and the retardation film is hindered and the deflection is disturbed. As a result, light leakage occurs in crossed Nicols and light loss occurs in parallel Nicols, which causes a decrease in optical performance, particularly contrast, of the display device. Therefore, an anisotropic optical film having a low retardation is required in order not to cause such performance degradation.

Japanese Patent No. 2547417

  An object of the present invention is to provide an anisotropic optical film having a small phase difference and less depolarization (light leakage) when anisotropy is improved when used in various display devices.

  When the material for forming the anisotropic optical film 50 having a plate-like structure was changed and studied, the problem of retardation was hardly improved. Therefore, the problem of retardation was determined by anisotropic optics having a plate-like structure. This is thought to be due to orientation birefringence resulting from molecular orientation based on the film structure. In particular, the use of a photocurable compound having a silicone skeleton that tends to cause molecular orientation as a material for forming an anisotropic optical film has an effect of improving anisotropy, but increases the phase difference and causes light leakage. However, it has a problem of becoming larger. That is, the improvement of anisotropy and the low phase difference are in a trade-off relationship. In order to solve the problem of retardation based on the molecular orientation of the photocurable compound having a silicone skeleton, the present inventors have intensively studied. By using a specific material, the problem of retardation and the problem of light leakage. The present invention has been completed. That is, the problem of phase difference due to molecular orientation is solved by material optimization.

(1) The film has at least a low refractive index region and a high refractive index region. The low refractive index region and the high refractive index region are alternately arranged on the film surface. An anisotropic optical film having a structure in which a refractive index region and a high refractive index region extend in the thickness direction, wherein at least a monomer, oligomer, prepolymer or macromonomer of a photocurable compound having a silicone skeleton is cured. An anisotropic optical film which is formed and has an in-plane retardation of 25 nm or less.
(2) The anisotropic optical film as described in (1) above, wherein the photocurable compound having a silicone skeleton is formed by blending and curing a compound having no silicone skeleton.
(3) The ratio of the photocurable compound having the silicone skeleton to the compound not having the silicone skeleton is in a range of 15:85 to 85:15 by mass ratio. Anisotropic optical film.
(4) In the low refractive index region, the amount of silicone resin that is a cured product of the photocurable compound having the silicone skeleton is relatively large, and in the high refractive index region, the compound does not have the silicone skeleton. The anisotropic optical film as described in (1) above, wherein is relatively large.
(5) The anisotropic optical film as described in (1) above, wherein the photocurable compound having the silicone skeleton is silicone, urethane, (meth) acrylate having an acryloyl group or a methacryloyl group at the terminal. .
(6) The compound having no silicone skeleton is at least selected from a compound having a cardo structure, a compound having two or more aromatic rings in one molecule, a cyclic hydrocarbon compound having a crosslinked structure, and a spiro compound. A kind of compound is used, The anisotropic optical film as described in said (1) characterized by the above-mentioned.
(7) The compound having no silicone skeleton is a compound having one or more acryloyl group or methacryloyl group in one molecule, and the skeleton has fluorene, adamantane, biphenyl, bisphenol A, diphenyl oxide, diphenyl The anisotropic optical film as described in (1) above, which is either sulfone or diphenyl sulfide.
(8) The anisotropic optical film as described in (1) above, wherein the compound having no silicone skeleton is contained in the total composition in an amount of 10 to 60% by mass.

ADVANTAGE OF THE INVENTION According to this invention, when using for various display apparatuses, while improving anisotropy, the anisotropic optical film with a small phase difference and few deflection elimination (light leakage) can be provided.
Furthermore, according to the present invention, since an anisotropic optical film having a low retardation can be provided, an alternative to a low retardation film such as triacetyl cellulose (TAC) or cycloolefin polymer (COP) used in a liquid crystal display device. Therefore, it is possible to use the film in combination with the film, so that a merit that leads to cost reduction can be expected.

It is a schematic diagram of the anisotropic optical film of this invention, Comprising: (a) A perspective view, (b) It is sectional drawing. The measurement method of an optical profile is shown. 1 represents an optical profile of an anisotropic optical film. It is a schematic diagram of the anisotropic diffusion film of the comparative example 1 which has many rod-shaped micro area | regions. It is the scanning electron micrograph (SEM) image | photographed after carbon-depositing the structure of the anisotropic optical film cross section of Example 1. FIG. It is the figure which mapped in carbon atom (C) with the energy dispersive X-ray detector (EDS) about the anisotropic optical film cross section of Example 1. FIG. It is the figure which mapped in the silicon atom (Si) with the energy dispersive X-ray detector (EDS) about the anisotropic optical film cross section of Example 1. FIG.

  Here, the definitions of each term in the claims and the specification will be described.

  The “low refractive index region” and the “high refractive index region” are regions formed by a difference in local refractive index of the material constituting the anisotropic optical film and have a lower refractive index than the other. It is a relative one indicating whether it is expensive. These regions are formed when the material forming the anisotropic optical film is cured.

The linear transmittance relates to the linear transmittance of light incident on the optical film, and is the ratio between the amount of transmitted light in the linear direction and the amount of incident light when incident from a certain incident angle. Is done.
Linear transmittance (%) = (Linear transmitted light amount / incident light amount) × 100

The contents of the present invention will be described below.
FIG. 1 is a schematic view of an anisotropic optical film 50 of the present invention. As shown in FIG. 1A, a plurality of plate-like structures 40 are formed in the anisotropic optical film 50. As shown in FIG. 1B of the cross-sectional view, the plate-like structure 40 includes low refractive regions 41 and high refractive index regions 42 alternately. Even on the film surface, the low refractive index regions 41 and the high refractive index regions 42 are alternately arranged. That is, the anisotropic optical film 50 of the present invention forms a structure in which the low refractive index region 41 and the high refractive index region 42 on the film surface extend in the thickness direction.
In addition to the low refractive region 41 and the high refractive region 42, other refractive index regions may be included. As another refractive index area | region, a middle refractive index area | region is mentioned, for example.

  In FIG. 1, the interface between the low refractive index region 41 and the high refractive index region 42 is drawn as a straight line, but the interface may be substantially linear. Even if it is substantially linear, the incident angle dependency as shown in FIG. 3 is exhibited.

Method for Producing Anisotropic Optical Film The anisotropic optical film of the present invention can be produced by irradiating a specific photocurable compound with ultraviolet (UV) light under special conditions. Hereinafter, the raw material of the anisotropic optical film will be described first, and then the manufacturing process will be described.

Raw Material for Anisotropic Optical Film The material forming the anisotropic optical film of the present invention is composed of a photocurable compound monomer, oligomer, prepolymer or macromonomer having a silicone skeleton and a photoinitiator. It is a material that is polymerized and solidified by irradiation with visible light.
Here, even if there is only one kind of material for forming the anisotropic optical film, a difference in refractive index occurs due to the difference in density. This is because a portion having a high UV irradiation intensity has a fast curing speed, and thus the cured material moves around the cured region, and as a result, a region having a higher refractive index and a region having a lower refractive index are formed.
In addition, (meth) acrylate means that either acrylate or methacrylate may be sufficient.

(Photo-curable compound having a silicone skeleton)
The photocurable compound having the silicone skeleton is oriented and polymerized / solidified in accordance with its structure (mainly ether bond), and has a low refractive index region, a high refractive index region, or a low refractive index region and a high refractive index region. Form. Thereby, the anisotropy which is a fundamental characteristic as an anisotropic optical film can be expressed.

In the low refractive index region, it is preferable that the silicone resin, which is a cured product of the photocurable compound having a silicone skeleton, is relatively increased. This further improves the anisotropy of the anisotropic optical film.
Since a silicone resin contains more silica (Si) than a compound having no silicone skeleton, the relative use of the silicone resin can be achieved by using an EDS (energy dispersive X-ray spectrometer) with this silica as an index. The amount can be confirmed.

The photocurable compound having a silicone skeleton is a monomer, oligomer, prepolymer or macromonomer having a radically polymerizable or cationically polymerizable functional group. Examples of the radical polymerizable functional group include an acryloyl group, a methacryloyl group, and an allyl group. Examples of the cationic polymerizable functional group include an epoxy group and an oxetane group. There are no particular restrictions on the type and number of these functional groups, but it is preferable to have a polyfunctional acryloyl group or methacryloyl group because the higher the functional groups, the higher the crosslink density and the greater the difference in refractive index. . Moreover, although the compound which has a silicone frame | skeleton may be inadequate in compatibility with another compound from the structure, in such a case, it can urethanize and can improve compatibility. In the present invention, silicone, urethane, (meth) acrylate having an acryloyl group or a methacryloyl group at the terminal is preferably used.

  The weight average molecular weight (Mw) of the photocurable compound having a silicone skeleton is preferably in the range of 500 to 50,000. More preferably, it is the range of 2,000-20,000. When the weight average molecular weight is in the above range, a sufficient photocuring reaction occurs, the silicone resin present in the anisotropic optical film is easily oriented, and anisotropy is more easily exhibited.

Examples of the silicone skeleton include those represented by the following general formula (1). In the general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are each independently a methyl group, an alkyl group, a fluoroalkyl group, a phenyl group, an epoxy group, an amino group, a carboxyl group. And a functional group such as a polyether group, an acryloyl group, and a methacryloyl group.
In general formula (1), n is preferably an integer of 1 to 500.

(Compound without silicone skeleton)
When an anisotropic optical film is formed by blending a photocurable compound having a silicone skeleton with a compound that does not have a silicone skeleton, the low refractive region and the high refractive index region are easily separated and formed anisotropic. The degree of is strong and preferable. As the compound having no silicone skeleton, a thermoplastic resin and a thermosetting resin can be used in addition to the photocurable compound, and these can be used in combination. As the photocurable compound, a polymer, oligomer, or monomer having a radical polymerizable or cationic polymerizable functional group can be used (however, it does not have a silicone skeleton). Examples of the thermoplastic resin include polyester, polyether, polyurethane, polyamide, polystyrene, polycarbonate, polyacetal, polyvinyl acetate, acrylic resin, and a copolymer or modified product thereof. In the case of using a thermoplastic resin, it is dissolved using a solvent in which the thermoplastic resin dissolves, and after application and drying, the photocurable compound having a silicone skeleton is cured with ultraviolet rays to form an anisotropic optical film. Examples of the thermosetting resin include epoxy resins, phenol resins, melamine resins, urea resins, unsaturated polyesters, copolymers thereof, and modified products. In the case of using a thermosetting resin, the photocurable compound having a silicone skeleton is cured with ultraviolet rays and then appropriately heated to cure the thermosetting resin and form an anisotropic optical film. The most preferable compound that does not have a silicone skeleton is a photo-curing compound, which easily separates a low refractive index region from a high refractive index region, and does not require a solvent and a drying process when using a thermoplastic resin. It is excellent in productivity, such as being unnecessary and a thermosetting process like a thermosetting resin is unnecessary.

  The refractive index difference (absolute value) between the low refractive index region and the high refractive index region is preferably 0.02 or more. More preferably, it is 0.03 or more, More preferably, it is 0.04 or more. As the refractive index difference increases, the degree of anisotropy increases, and it becomes easier to confirm whether a plate-like structure is formed with an optical microscope or the like.

  Radical polymerizable compounds mainly contain one or more unsaturated double bonds in the molecule, and are specifically called by names such as epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, polybutadiene acrylate, etc. Acrylic oligomer, 2-ethylhexyl acrylate, isoamyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isonorbornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-acrylic Leuoxyphthalic acid, dicyclopentenyl acrylate, triethylene glycol diacrylate, neopentyl glycol di Chlorate, 1,6-hexanediol diacrylate, EO adduct diacrylate of bisphenol A, EO modified phenyl acrylate, adamantane acrylate, biphenyl acrylate, phenoxyphenyl acrylate, trimethylolpropane triacrylate, EO modified trimethylolpropane triacrylate, penta Examples include acrylate monomers such as erythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexaacrylate. In addition, these compounds may be used alone or in combination. Similarly, although methacrylate can be used, acrylate is generally preferable to methacrylate because it has a higher photopolymerization rate.

  As the cationically polymerizable compound, a compound having at least one epoxy group, vinyl ether group or oxetane group in the molecule can be used. The compounds having an epoxy group include 2-ethylhexyl diglycol glycidyl ether, glycidyl ether of biphenyl, bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetrachloro Diglycidyl ethers of bisphenols such as bisphenol A and tetrabromobisphenol A, polyglycidyl ethers of novolac resins such as phenol novolak, cresol novolak, brominated phenol novolak, orthocresol novolak, ethylene glycol, polyethylene glycol, polypropylene glycol, Butanediol, 1,6-hexanediol, neopentyl glycol, trimethyl Diglycidyl ethers of alkylene glycols such as propane adduct of 1,4-cyclohexanedimethanol, bisphenol A, PO adduct of bisphenol A, glycidyl ester of hexahydrophthalic acid, diglycidyl ester of dimer acid, etc. Examples thereof include glycidyl esters.

  Further, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, di (3,4-epoxycyclohexylmethyl) adipate, di (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6′-methyl Cyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate), lactone modification 3, -Epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, tetra (3,4-epoxycyclohexylmethyl) butanetetracarboxylate, di (3,4-epoxycyclohexylmethyl) -4,5-epoxytetrahydrophthalate, etc. Although the alicyclic epoxy compound of these is also mentioned, it is not limited to these.

  Examples of the compound having a vinyl ether group include diethylene glycol divinyl ether, triethylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, hydroxybutyl vinyl ether, ethyl vinyl ether, dodecyl vinyl ether, and trimethylolpropane trivinyl ether. , Propenyl ether propylene carbonate and the like, but are not limited thereto. Vinyl ether compounds are generally cationically polymerizable, but radical polymerization is also possible by combining with acrylates.

  As the compound having an oxetane group, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 3-ethyl-3- (hydroxymethyl) -oxetane and the like can be used.

The above cationic polymerizable compounds may be used alone or in combination. The photopolymerizable compound is not limited to the above. In order to cause a sufficient difference in refractive index, fluorine atoms (F) may be introduced into the photopolymerizable compound in order to reduce the refractive index, and in order to increase the refractive index, Sulfur atoms (S), bromine atoms (Br), and various metal atoms may be introduced. Further, as disclosed in JP 2005-514487, on the surface of ultrafine particles made of a metal oxide having a high refractive index such as titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), tin oxide (SnOx), It is also effective to add functional ultrafine particles into which a photopolymerizable functional group such as an acryl group, a methacryl group, or an epoxy group is introduced.

In the present invention, it is preferable to use a compound having an action of disturbing molecular orientation of a compound having a silicone skeleton as a compound having no silicone skeleton. For example, it is preferable to use at least one compound selected from a compound having a cardo structure, a compound having two or more aromatic rings in one molecule, a cyclic hydrocarbon compound having a crosslinked structure, and a spiro compound. The compound having no silicone skeleton may be one type or a plurality of types.

  Here, the cardo structure is a structure in which two cyclic structures are bonded to a quaternary carbon in a cyclic structure, and a typical compound having this is a compound in which an aromatic ring is bonded to a fluorene ring. Examples of the compound having two or more aromatic rings in one molecule are compounds having a structure in which aromatic rings such as biphenyl, bisphenol A, diphenyl oxide, diphenyl sulfone, and diphenyl sulfide are connected by a bond. Examples of the cyclic hydrocarbon compound having a crosslinked structure are compounds having a skeleton such as norbornene, camphor, tricyclodecane, adamantane, and the spiro compound, in which two cyclic compounds share one carbon. Typical compounds include spirobiindane and spiroacetal. Since these compounds are bulky in structure, the cyclic structure is easily twisted in the conformation, or it is easy to take a bent structure, it is considered that the molecular orientation can be partially disturbed.

As a compound that does not have a silicone skeleton, it is a compound having one or more acryloyl group or methacryloyl group in the molecule, and the skeleton is fluorene, adamantane, biphenyl, bisphenol A, diphenyl oxide, diphenylsulfone, diphenylsulfide It is preferable that the compound which is either is included. Such a compound having a photopolymerizable functional group is easily available, and has sufficient anisotropy due to molecular orientation of a compound having a silicone skeleton by photocuring simultaneously with a photocurable compound having a silicone skeleton. However, it is considered that the phase difference can be lowered by partially disturbing the orientation. As a specific example of such a compound, as a compound having a fluorene skeleton, Ogsol EA-0200, Oxol EA-F5003, Oxol EA-F5503, Oxol EA-F5510 manufactured by Osaka Gas Chemical Company, Shin-Nakamura Chemical Co., Ltd. A-BPEF (9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene) and the like, and compounds having an adamantane skeleton include adamantate M-104 and adamantate X-manufactured by Idemitsu Kosan Co., Ltd. A-101, adamantate X-A-201, adamantate MM, adamantate EM, adamantate HM, adamantate HA, adamantate MA, adamantate EA, etc. are mentioned. New Frontier OPPE manufactured by Pharmaceutical Examples of the compound having a bisphenol A skeleton include EO adduct di (meth) acrylate of bisphenol A, PO adduct di (meth) acrylate of bisphenol A, and bisphenol A epoxy acrylate. Examples of the compound having a diphenyl oxide skeleton include light acrylate POB-A (m-phenoxybenzyl acrylate) manufactured by Kyoeisha Chemical Co., Ltd., and examples of the compound having a diphenyl sulfone skeleton include 4,4′-bis (β- (meta ) Acryloyloxyethoxy) diphenyl sulfone and the like, and examples of the compound having a diphenyl sulfide skeleton include 4,4′-di (β- (meth) acryloyloxyethoxy) diphenyl sulfide. Is not to be done. It is also possible to use a plurality of these compounds.

In the high refractive index region, it is preferable that a cured product of a compound having no silicone skeleton (if the compound is an acrylate, the cured product is an acrylic resin) is relatively increased. Thereby, anisotropy can be further improved.
Since a compound having no silicone skeleton contains more carbon (C) than a photocurable compound having a silicone skeleton, by using this carbon as an index, an EDS (energy dispersive X-ray spectrometer) is used. Can be confirmed.

(Photoinitiator)
Raw material for anisotropic optical film (photoinitiator)
Photoinitiators that can polymerize radically polymerizable compounds include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2- Diethoxyacetophenone, benzyldimethyl 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-propane-1 -One, bis (cyclo Ntadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) titanium, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,4,6 -Trimethyl benzoyl diphenyl phosphine oxide etc. Moreover, these compounds may be used individually or may be used in mixture of two or more.

The photoinitiator of a cationic polymerizable compound is a compound that generates an acid by light irradiation and can polymerize the above-mentioned cationic polymerizable compound with the generated acid. Generally, an onium salt or a metallocene complex is used. Preferably used. As the onium salt, a diazonium salt, a sulfonium salt, an iodonium salt, a phosphonium salt, a selenium salt, or the like is used, and these counter ions include anions such as BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ^{− and the} like. Used. Specific examples include 4-chlorobenzenediazonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, (4-phenylthiophenyl) diphenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl) diphenyl. Sulfonium hexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluorophosphate, (4-methoxyphenyl) Diphenylsulfonium hexafluoroantimonate, (4-methoxyphenyl) phenyliodonium hexafluoroantimonate Bis (4-t-butylphenyl) iodonium hexafluorophosphate, benzyltriphenylphosphonium hexafluoroantimonate, triphenyl selenium hexafluorophosphate, (η5-isopropylbenzene) (η5-cyclopentadienyl) iron (II) hexa Although fluorophosphate etc. are mentioned, it is not limited to these. In addition, these compounds may be used alone or in combination.

Raw material for anisotropic optical film (blending amount, other optional components)
In the present invention, the photoinitiator is added in an amount of 0.001 part by mass with respect to 100 parts by mass of the total amount of the photocurable compound contained in the composition comprising a photocurable compound having a silicone skeleton and a compound having no silicone skeleton. 01 to 10 parts by mass, preferably 0.1 to 7 parts by mass, more preferably about 0.1 to 5 parts by mass. This is because if less than 0.01 parts by mass, the photocurability is lowered, and if more than 10 parts by mass is blended, only the surface is cured and the internal curability is lowered, resulting in anisotropy. This is because the reduction and the inhibition of the formation of the plate-like structure are caused. These photoinitiators are usually used by dissolving the powder directly in the mixture of the above composition, but if the solubility is poor, the photoinitiator is dissolved in a very small amount of solvent in advance at a high concentration. Can also be used. Such a solvent is more preferably photopolymerizable, and specific examples thereof include propylene carbonate and γ-butyrolactone. It is also possible to add various known dyes and sensitizers in order to improve the photopolymerizability. Further, a thermosetting initiator capable of curing the photopolymerizable compound by heating can be used in combination with the photoinitiator. In this case, by heating after photocuring, it can be expected to further accelerate the polymerization and curing of the photopolymerizable compound to complete it.

  In the present invention, an anisotropic diffusion layer can be formed by curing a composition in which a photocurable compound having a silicone skeleton and a compound not having a silicone skeleton are mixed. Any compound can be mixed. In addition, known additives such as a plasticizer, an antioxidant, a light stabilizer, a surfactant, and a leveling agent can be added to the composition as necessary. In particular, plasticizers, surfactants, leveling agents, plasticizers, etc. are effective for improving film-forming properties, and include plasticizers such as phthalic polyester and adipic acid polyester, and silicone and acrylic leveling agents. The addition amount is preferably 0.5 to 10% by weight in the total composition.

The ratio of the photocurable compound having a silicone skeleton and the compound not having a silicone skeleton is preferably in the range of 15:85 to 85:15 by mass ratio. More preferably, it is the range of 30: 70-70: 30. By setting it in this range, phase separation between the low refractive index region and the high refractive index region can easily proceed. If the ratio of the photocurable compound having a silicone skeleton is less than the lower limit value or exceeds the upper limit value, the phase separation is difficult to proceed, and the problem of insufficient anisotropy is difficult to solve. The compounding amount of the compound which is at least one compound selected from a compound having a cardo structure, a compound having two or more aromatic rings in one molecule, a cyclic hydrocarbon compound having a crosslinked structure, and a spiro compound, It is preferable that it is 10-60 mass% with respect to the whole photocurable resin composition. If the addition amount is less than the lower limit, the effect of disturbing the molecular orientation is lost and the effect of lowering the phase difference cannot be expected. If the addition amount is too large, the orientation is too disturbed and the original optical anisotropy is impaired. A more preferable blending amount is 15 to 45% by mass, and a sufficient decrease in retardation can be exhibited. The anisotropic optical film of the present invention can realize both anisotropy and a low retardation that could not be achieved conventionally by appropriately selecting the compound and the blending amount thereof, and the retardation is an optical film. It can be made sufficiently low 25 nm or less. Furthermore, it is possible to make the thickness 10 nm or less, and the retardation can be equivalent to that of a TAC film, COP film or polycarbonate (PC) sheet conventionally used as a low retardation film. It is also possible to do. That is, the anisotropic optical film of the present invention can be used as a protective film for a polarizing plate. As described above, since the anisotropic optical film obtained by the present invention has a low phase difference, it hardly causes light leakage even when it exists between the crossed Nicols of the polarizing plate, and between the parallel Nicols of the polarizing plate. Even when it is present, optical loss is less likely to occur, and when used for a display or the like, a decrease in luminance is suppressed, contributing to an improvement in contrast.

[process]
Next, the manufacturing method (process) of the anisotropic optical film of this invention is demonstrated. The above-mentioned anisotropic optical film forming material (photocurable resin composition) is coated on a suitable base material such as a transparent polyethylene terephthalate (PET) film to provide a coating film. Although it dries as needed and a solvent is volatilized, the dry film thickness is 10-500 micrometers, More preferably, it is 20-200 micrometers, More preferably, it is 30-100 micrometers. When the dry film thickness is less than 10 μm, the light diffusibility obtained through the UV irradiation process described later is poor, which is not preferable. On the other hand, when the dry film thickness exceeds 500 μm, the overall diffusibility is too strong, and it becomes difficult to obtain the characteristic anisotropy of the present invention, and it is not preferable because of cost increase and incompatibility with thinning applications. . Furthermore, a release film or a mask described later can be laminated on the coating film to produce a photosensitive laminate.

(Method of providing a photocurable resin composition containing a photocurable compound having a silicone skeleton in a sheet form on a substrate)
Here, as a method of providing a photocurable resin composition containing a photocurable compound having a silicone skeleton in a sheet form on a substrate, a normal coating method or printing method is applied. Specifically, 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 Coating such as die coating, intaglio printing such as gravure printing, printing such as stencil printing such as screen printing, and the like can be used. When the photocurable resin composition has a low viscosity, a weir with a certain height can be provided around the substrate, and the photocurable resin composition can be cast in the area surrounded by the weir.

(light source)
As a light source for irradiating the coating film with light, a short arc ultraviolet ray generating light source is usually used. Specifically, a high pressure mercury lamp, a low pressure mercury lamp, a metahalide lamp, a xenon lamp, or the like can be used. The light beam applied to the photocurable resin composition containing the photocurable compound needs to include a wavelength capable of curing the photocurable compound. Usually, light having a wavelength centered at 365 nm of a mercury lamp is emitted. Used.
The shape of the light source is preferably linear, and a light source that looks substantially linear when viewed from the irradiated position may be used. As a method for obtaining such a linear light beam, a known method using various light sources and lenses can be used. In the present invention, as a simple method, an example is shown in which a diffused light source is converted into a parallel light beam using a Fresnel lens or the like, and the parallel light beam is further converted into a linear light beam diffused in only one direction via a lenticular lens. This is not the case.

  In order to make a parallel light beam from the light from the short arc UV light, for example, a reflecting mirror is arranged behind the light source so that the light is emitted as a point light source in a predetermined direction, and the light is further emitted into the Fresnel. The lens can make parallel light. A Fresnel lens is a lens in which a normal lens is divided into concentric regions to reduce the thickness, and has a saw-like cross section. When the light beam emitted from the point light source passes through the Fresnel lens, the directions of the light beams having different directions are unified in one direction to become parallel light beams. However, in order to obtain parallel UV emission light necessary for producing the anisotropic optical film of the present invention, a Fresnel lens is not necessarily required, and various methods including a laser can be used. .

  A part of the parallel light beam is converted into a linear light beam by causing the parallel light beam described above to enter the flat surface of the lenticular lens and to be emitted from the uneven surface of the lenticular lens. That is, a parallel light beam and a linear light beam can be obtained through the lenticular lens.

  The above-described UV irradiation method using a lenticular lens is one method for producing the anisotropic optical film of the present invention, and the present invention is not limited to this. In short, in order to form a specific internal structure in the photocurable composition layer, it is important to irradiate the photosensitive laminate with UV light that spreads in a flat fan shape.

  That is, a fine structure having a high and low refractive index according to the present invention is formed by the step of irradiating the photocurable composition layer with light spreading in a plane fan shape. In addition, the light to irradiate has a wavelength which can harden the said photocurable composition. In the irradiation step, it is preferable to use light obtained by diffusing parallel rays into a flat fan shape.

When producing the anisotropic optical film of this invention, it is preferable that it is the range of 0.01-100 mW / cm < ² > as illumination intensity of UV light irradiated to a coating film, More preferably, it is 0.1-0.1. The range is 20 mW / cm ² . If the illuminance is 0.01 mW / cm ² or less, it takes a long time to cure, resulting in poor production efficiency. If the illuminance is 100 mW / cm ² or more, the photo-curing compound is cured too quickly to form a structure, This is because the desired anisotropic diffusion characteristic cannot be expressed.

  Although the irradiation time of UV is not particularly limited, it is 10 to 180 seconds, more preferably 30 to 120 seconds. Then, the anisotropic optical film of this invention can be obtained by peeling a release film.

The anisotropic optical film of the present invention is obtained by forming a specific internal structure in a photocurable composition by irradiating with low-intensity UV light for a relatively long time as described above. For this reason, unreacted monomer components remain by such UV irradiation alone, and stickiness may occur, which may cause problems in handling properties and durability. In such a case, the residual monomer can be polymerized by additional irradiation with UV light having a high illuminance of 1000 mW / cm ² or more. The UV irradiation at this time is preferably performed from the opposite side (base material side) of the direction in which the UV irradiation was performed first.

Display Device The anisotropic optical film of the present invention is a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display device (CRT), a surface electric field display (SED), an electronic paper. It can be applied to such a display device. It is particularly preferably used for a liquid crystal display (LCD). The anisotropic optical film of the present invention is formed by curing a photocurable compound having a silicone skeleton, but there are few problems of adhesive strength, and it can be placed at a desired place via an adhesive layer or an adhesive layer. Can be used together.
The anisotropic optical film of the present invention can be preferably used for a transmissive, reflective, or transflective liquid crystal display device.

  According to the following method, the anisotropic optical film of the present invention and the anisotropic optical film of the comparative example were produced.

[Example 1]
A partition wall having a height of 0.2 mm was formed with a curable resin on the entire periphery of the edge of a PET film (trade name: A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and a size of 76 × 26 mm. This was filled with the following photocurable resin composition and covered with another PET film.
-Silicone urethane acrylate (refractive index: 1.460) 65 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
Bisphenol A EO adduct diacrylate (refractive index: 1.536) 35 parts by weight (manufactured by Daicel Cytec, trade name: Ebecyl 150)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)
Parallel light emitted from an irradiation unit for epi-illumination of a UV spot light source (trade name: L2859-01, manufactured by Hamamatsu Photonics Co., Ltd.) is applied to a liquid film having a thickness of 0.2 mm between both surfaces sandwiched by PET films. The anisotropy of Example 1 in which ultraviolet rays converted into linear rays through a lenticular lens are irradiated vertically for 1 minute at an irradiation intensity of 10 mW / cm ² and have a large number of linear minute regions as shown in FIG. An ionic diffusion medium was obtained. From there, the PET film was peeled off to obtain the anisotropic diffusion film of the present invention.

[Example 2]
An anisotropic diffusion film of Example 2 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 45 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
Fluorene skeleton diacrylate (refractive index: 1.591) 12 parts by weight (manufactured by Osaka Gas Chemical Co., Ltd., trade name: Oxol EA-F5503)
・ Phenoxyethyl acrylate (refractive index: 1.518) 43 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Example 3]
An anisotropic diffusion film of Example 3 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 45 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
・ Adamantane skeleton acrylate (refractive index: 1.521) 15 parts by weight (made by Idemitsu Kosan Co., Ltd., trade name: adamantate X-A-101)
・ Phenoxyethyl acrylate (refractive index: 1.518) 40 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Example 4]
An anisotropic diffusion film of Example 4 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 30 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
15 parts by weight of trimethylolpropane triacrylate (refractive index: 1.474) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate TMP-A)
-Biphenyl skeleton acrylate (refractive index: 1.568) 15 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd., trade name: New Frontier OPPE)
・ Phenoxyethyl acrylate (refractive index: 1.518) 40 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Example 5]
An anisotropic diffusion film of Example 5 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 25 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
5 parts by weight of trimethylolpropane triacrylate (refractive index: 1.474) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate TMP-A)
15 parts by weight of urethane acrylate (refractive index: 1.491) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: UA-306I)
-Epoxy acrylate (refractive index: 1.523) 40 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: epoxy ester M-600A)
・ Diphenyl oxide skeleton acrylate (refractive index: 1.566) 15 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate POB-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Comparative Example 1]
An anisotropic diffusion film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
・ 55 parts by weight of silicone / urethane / acrylate (refractive index: 1.460) (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
・ Phenoxyethyl acrylate (refractive index: 1.518) 45 parts by weight (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Comparative Example 2]
An anisotropic diffusion film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 30 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
15 parts by weight of trimethylolpropane triacrylate (refractive index: 1.474) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate TMP-A)
Bisphenol A EO adduct diacrylate (refractive index: 1.536) 5 parts by weight (manufactured by Daicel Cytec, trade name: Ebecyl 150)
・ Phenoxyethyl acrylate (refractive index: 1.518) 50 parts by weight (Kyoeisha Chemical Co., Ltd., trade name: Light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

[Comparative Example 3]
A diffusion film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the following photocurable resin composition was used.
Silicone urethane acrylate (refractive index: 1.460) 10 parts by weight (manufactured by RAHN, trade name: 00-225 / TM18, weight average molecular weight: 5,890)
Bisphenol A EO adduct diacrylate (refractive index: 1.536) 90 parts by weight (manufactured by Daicel Cytec, trade name: Ebecyl 150)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by weight (manufactured by BASF, trade name: Irgacure 651)

The weight average molecular weight (Mw) of the silicone, urethane, and acrylate used in Examples 1 to 5 and Comparative Examples 1 to 3 was measured under the following conditions using a GPC method as a molecular weight in terms of polystyrene.
Degasser: DG-980-51 (manufactured by JASCO Corporation)
Pump: PU-980-51 (manufactured by JASCO Corporation)
Autosampler: AS-950 (manufactured by JASCO Corporation)
Thermostatic chamber: C-965 (manufactured by JASCO Corporation)
Column: Shodex KF-806L x 2 (made by Showa Denko KK)
Detector: RI (SHIMAMURA YDR-880)
Temperature: 40 ° C
Eluent: THF
Injection volume: 150 μl
Flow rate: 1.0ml / min
Sample concentration: 0.2%

(Evaluation by SEM and EDS)
SEM and EDS were photographed under the following conditions.
SEM
The cross-sectional state of the anisotropic optical film obtained in Example 1 and information on the contained elements were observed by SEM and EDS. Observation was performed after carbon deposition on the surface of the anisotropic optical layer. The conditions for SEM and EDS observation are shown below.
Analyzer JSM-6460LV (manufactured by JEOL Ltd.) / INCA (manufactured by OXFORD)
Pretreatment device C (carbon) coating: 45 nm SC-701C (manufactured by Sanyu Electronics Co., Ltd.)
SEM condition Acceleration voltage: 15KV
Irradiation current: 0.15 nA
Degree of vacuum: High vacuum
Image detector: backscattered electron detector
Sample tilt: 0 degree

(Anisotropy evaluation of anisotropic diffusion film)
The anisotropic diffusion films of the examples and comparative examples were evaluated using a variable angle photometer goniophotometer (manufactured by Genesia Co., Ltd.) capable of arbitrarily changing the light projecting angle of the light source and the light receiving angle of the light receiver. The light-receiving part was fixed at a position where it received straight light from the light source, and the anisotropic diffusion films obtained in Examples and Comparative Examples were set in the sample holder therebetween. As shown in FIG. 2, the sample was rotated as the rotation axis (L), and the amount of linear transmitted light corresponding to each incident angle was measured. By this evaluation method, it is possible to evaluate in which angle range the incident light is diffused, that is, it is possible to know the diffusion anisotropy. The rotation axis (L) is the same axis as the BB axis in the sample structure shown in FIG. The linear transmitted light amount was measured by measuring the wavelength in the visible light region using a visibility filter.

(Evaluation of retardation of anisotropic diffusion film)
In-plane retardation of the anisotropic diffusion films of Examples and Comparative Examples was measured using a phase difference measuring device KOBRA-WR of Oji Scientific Instruments. The measurement wavelength was 586.5 nm, the phase difference was measured by changing the incident angle, and the measurement value that gave the highest phase difference was evaluated.

(Evaluation of light leakage between crossed Nicols of anisotropic diffusion film)
Two polarizing plates were prepared and overlapped so as to be crossed Nicols, and the anisotropic diffusion films of Examples and Comparative Examples were sandwiched therebetween, and light leakage was observed. In order to quantitatively evaluate the light leakage, a haze meter NDH-2000 manufactured by Nippon Denshoku Co., Ltd. was used, and the total light transmittance (TT ₀ ) of a crossed Nicol polarizing plate without sandwiching an anisotropic diffusion film was used as a reference. The total light transmittance (TT ₁ ) in a state where the isotropic diffusion film was sandwiched was measured, and the difference was evaluated as a change in transmittance of light leakage (ΔTT = TT ₁ −TT ₀ ). In this measurement, the anisotropic diffusion film was rotated and evaluated using the measured value that gave the highest transmittance. ΔTT is preferably as low as possible, and is practically used at 1.0 or less, and can be preferably used at 0.8 or less.

The optical anisotropy was evaluated from the linear transmittance measured by the goniophotometer of Examples and Comparative Examples, and is shown in Table 1. The anisotropic optical films of Examples 1 to 5 and Comparative Examples 1 and 2 showed sufficient optical anisotropy because the linear transmittance depending on the incident angle of the light beam had a large amount of change due to a difference of 50% or more. I was able to judge. On the other hand, the optical film of Comparative Example 3 has a linear transmittance with a difference of about 15% due to the incident angle of the light beam, so that the amount of change is small and does not exhibit sufficient optical anisotropy, and also has sufficient diffusion in the diffusion region. I couldn't say that.

Table 1 shows the measurement results of the phase difference (Re) and the light leakage transmittance change (ΔTT) in the examples and comparative examples. It can be seen that the phase differences in Examples 1 to 5 are sufficiently low at 25 nm or less and the light leakage is small. Further, in particular, the anisotropic optical films of Examples 4 to 5 have a low phase difference of 10 nm or less, and light leakage is almost zero. On the other hand, it can be seen that the phase difference of the comparative example is high and the light leakage is large. An optical film having a small phase difference and little light leakage at the crossed Nicol polarizing plate can be said to be useful as an optical film that contributes to improvement in luminance and contrast when used in various displays.

  As shown in FIG. 5, the cross-sectional view of the anisotropic optical film of Example 1 shows that low refractive index regions and high refractive index regions are alternately formed. The anisotropic optical film of Example 1 was mapped by EDS. FIG. 6 shows carbon and FIG. 7 shows silicon. 6 and 7 were measured in the same visual field. The closer the concentration of the measured element is, the closer it is to black, and vice versa. As shown in FIGS. 6 and 7, it was confirmed that the shading was linear. In addition, it is shown that the mapping is almost opposite between carbon and silicon. That is, it can be seen that the silicon concentration is low at locations where the carbon concentration is high, and the silicon concentration is high where the carbon concentration is low. This is a result showing that the material forming the anisotropic optical film is linearly oriented, and the silicone resin, which is a cured product of the photocurable compound having a silicone skeleton, is relatively linear. The part which has increased and the part where the compound which does not have a silicone frame | skeleton has increased relatively linearly are shown.

  As described above, according to the present invention, it is possible to provide an anisotropic diffusion film with a large amount of change in the amount of linear transmitted light depending on the incident angle of the light beam, and since the anisotropic diffusion film has a small phase difference, Excellent visibility can be obtained by using in various display devices.

Claims (8)

The film has at least a low refractive index region and a high refractive index region, and the low refractive index region and the high refractive index region are alternately arranged on the film surface. An anisotropic optical film having a structure in which a high refractive index region extends in the thickness direction, and is formed by curing a monomer, oligomer, prepolymer or macromonomer of a photocurable compound having at least a silicone skeleton. An anisotropic optical film characterized by having an in-plane retardation of 25 nm or less. The anisotropic optical film according to claim 1, wherein the anisotropic optical film is formed by blending and curing a compound having no silicone skeleton in the photocurable compound having the silicone skeleton. The anisotropy according to claim 1, wherein the ratio of the photocurable compound having the silicone skeleton and the compound not having the silicone skeleton is in a range of 15:85 to 85:15 by mass ratio. Optical film. In the low refractive index region, the silicone resin that is a cured product of the photocurable compound having the silicone skeleton is relatively large,
2. The anisotropic optical film according to claim 1, wherein in the high refractive index region, the amount of the compound having no silicone skeleton is relatively large. 2. The anisotropic optical film according to claim 1, wherein the photocurable compound having a silicone skeleton is a silicone / urethane / (meth) acrylate having an acryloyl group or a methacryloyl group at a terminal. The compound having no silicone skeleton is at least one compound selected from a compound having a cardo structure, a compound having two or more aromatic rings in one molecule, a cyclic hydrocarbon compound having a crosslinked structure, and a spiro compound. The anisotropic optical film according to claim 1, wherein: The compound having no silicone skeleton is a compound having at least one acryloyl group or methacryloyl group in one molecule, and the skeleton has fluorene, adamantane, biphenyl, bisphenol A, diphenyl oxide, diphenylsulfone, diphenyl The anisotropic optical film according to claim 1, wherein the anisotropic optical film is any one of sulfides. The anisotropic optical film according to claim 1, wherein the compound having no silicone skeleton is contained in an amount of 10 to 60% by mass in the entire composition.