JP2007086673A - Optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element having a photo-alignment layer that can develop alignment regulating force by irradiation with light and an optical functional layer comprising a liquid crystalline compound, wherein the adhesiveness between the photo-alignment layer and the optical functional layer is increased and durability of each layer is improved. <P>SOLUTION: The optical element comprises at least a support, a photo-alignment layer and an optical functional layer. The photo-alignment layer is formed by using a photo-alignment layer forming composition containing a compound having a photo-dimerizable group, and the optical functional layer is formed by using an optical functional layer forming composition, which contains one or more kinds of compounds, wherein any compound has one or more kinds among a photo-dimerizable group, an ethylenically unsaturated bond, and a liquid crystal property, and the composition as a whole includes a photo-dimerziable group, an ethylenically unsaturated bond and the liquid crystal property. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical element such as a retardation plate, a polarizing plate, a display color filter, and the like, and in particular, an alignment film capable of expressing an alignment regulating force by light irradiation, and an optical functional layer comprising a liquid crystalline compound It is related with the optical element provided with.

  In general, liquid crystals are used as a medium for display elements such as TN (twisted nematic) type and STN (super twisted nematic) type by utilizing the reversible mobility of molecular arrangement, as well as their orientation and refraction. Utilizing the rate anisotropy, it is also used as an optical element such as a retardation plate, a polarizing plate, and a color filter for display.

  Here, regarding the latter application, in recent years, many optical elements including a liquid crystal layer made of a polymerizable liquid crystal material as a refractive index anisotropic layer have been proposed. Specifically, Patent Document 1 discloses an optical element having functions of wavelength selective reflectivity and polarization selective reflectivity, which is manufactured using a special polymerizable liquid crystal compound. Patent Document 2 discloses a birefringent plate manufactured using a polymerizable liquid crystal compound having a rod-like structure. Further, Patent Document 3 discloses an optical compensation sheet produced using a polymerizable liquid crystal compound having a disk-like structure.

  By the way, as such an optical element, a plastic film or the like is used as a support, and an optical functional layer having an alignment property and refractive index anisotropy made of a polymerizable liquid crystal material is laminated on the support through an alignment film. What is used is generally used.

  Here, the alignment film provided between the support and the optical functional layer has an alignment regulating force that regulates the alignment direction of the liquid crystal molecules in the optical functional layer having refractive index anisotropy. Such an alignment film is formed, for example, by forming a polymer layer such as oriented polyimide or polyvinyl alcohol on a support and then subjecting the polymer layer to an alignment treatment such as a rubbing treatment. be able to. In addition, when rubbing is performed as an alignment process, there is a problem that static electricity and dust are generated on the surface of the alignment film. Therefore, a technique for expressing the alignment regulating force in the alignment film without performing the rubbing process has been studied. ing. One of them is a photo-alignment method in which alignment regulation force (anisotropy) is generated on the surface of the alignment film by irradiating light. An alignment film used for the photo-alignment method is called a photo-alignment film. The photo-alignment method has an advantage that the director direction of the liquid crystal in the optical functional layer can be easily controlled as compared with the rubbing treatment.

  Such photo-alignment methods include “photoisomerization” in which only the molecular shape is deformed to reversibly change the alignment state, and “photoreaction type” in which the molecule itself is changed. The latter “photoreactive type” is further divided into a dimerization type, a decomposition type, a binding type, a decomposition-bonding type, and the like.

  In an optical element composed of a support, a photo-alignment film and an optical functional layer as described above, it is of course important that the optical characteristics of each layer of the optical element are good. It is also important that the durability is good. Regarding the latter problem, for example, when the adhesion between the optical alignment film constituting the optical element and the optical functional layer is poor, there is a problem that the optical functional layer is easily peeled off from the optical alignment film.

In order to solve such problems, conventionally, the following methods have been proposed. Patent Document 4 proposes a method for eliminating stress cracks and improving the adhesion of the optical functional layer by disposing a layer exhibiting an indentation elastic modulus of less than 2 Gpa between the support and the photo-alignment film. This method does not directly attach the photo-alignment film and the optical functional layer, and is insufficient in practical use.
JP 2002-533742 A Japanese Patent Application Laid-Open No. 5-215921 JP-A-8-338913 JP 2004-139084 A

  Therefore, the present invention solves the above-mentioned problems of the prior art and is an optical element including a photo-alignment film capable of developing an alignment regulating force by light irradiation and an optical functional layer containing a liquid crystalline compound. Then, it aims at providing the optical element which can improve the adhesiveness between a photo-alignment film and an optical function layer, and can improve the durability of each layer.

  In order to solve the above-described problems, an optical element of the present invention is an optical element including at least a support, a photo-alignment film, and an optical functional layer, and the photo-alignment film includes a compound having a group capable of photodimerization. The optical functional layer is formed using the optical functional layer forming composition, and the optical functional layer forming composition is formed using the optical alignment layer forming composition. One or more compounds are included, and any compound has at least one of a group capable of photodimerization, an ethylenically unsaturated bond, and liquid crystallinity, and the composition as a whole can be photodimerized. It has a group, an ethylenically unsaturated bond, and liquid crystallinity.

  According to the present invention, both the composition for forming a photo-alignment film and the composition for forming an optical functional layer contain a compound having a group capable of photodimerization, so the affinity between the photo-alignment film and the optical functional layer is high, Adhesion at the interface between the photo-alignment film and the optical functional layer can be improved.

  FIG. 1 shows an example of a basic layer structure of the optical element of the present invention. In FIG. 1, 1 is a support, 2 is a photo-alignment film formed on the support 1, and 3 is an optical functional layer formed on the photo-alignment film 2. FIG. 2 shows still another example of the basic layer structure of the optical element of the present invention. The optical element of FIG. 2 is obtained by providing a barrier layer 4 between the support 1 and the photo-alignment film 2 in the optical element of FIG. Examples of the optical element having these layer structures include a retardation plate, a polarizing element, and a color filter for display.

  In the optical element of the present invention, the composition for forming a photo-alignment film used for the photo-alignment film and the composition for forming an optical function layer used for the optical function layer have the following combinations depending on the type of each composition. Can be mentioned.

  (1) The composition for forming a photo-alignment film includes a compound having a group capable of photodimerization, while the composition for forming an optical functional layer includes a group capable of photodimerization and an ethylenically unsaturated bond in one molecule. Liquid crystalline compounds having

  (2) The composition for forming a photo-alignment film includes a compound having a group capable of photodimerization, while the composition for forming an optical functional layer includes a group capable of photodimerization and an ethylenically unsaturated bond in one molecule. And a liquid crystalline compound having a plurality of ethylenically unsaturated bonds.

  (3) A compound having a group capable of photodimerization is included in the composition for forming a photoalignment film, while a group capable of photodimerization and an ethylenically unsaturated bond in one molecule are included in the composition for forming an optical functional layer. And a liquid crystal compound having a plurality of ethylenically unsaturated bonds.

<Optical function layer>
Examples of the composition for forming an optical functional layer used for the optical functional layer in the optical element of the present invention include the following types.

  (1) A composition for forming an optical functional layer comprising a liquid crystalline compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule.

  (2) A composition for forming an optical functional layer comprising a compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule and a liquid crystalline compound having a plurality of ethylenically unsaturated bonds.

  (3) A composition for forming an optical functional layer comprising a liquid crystalline compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule, and a liquid crystalline compound having a plurality of ethylenically unsaturated bonds.

  Examples of the group capable of photodimerization include cinnamate, coumarin, chalcone, benzylidenephthalimidine, benzylideneacetophenone, diphenylacetylene, stilbazole, uracil, quinolinone, thymine, maleimide, cinnamylideneacetic acid, and derivatives thereof.

  Examples of the compound having an ethylenically unsaturated bond include acrylates, methacrylates, vinyloxys, vinyl esters, styrenes, fumaric acid esters, and maleic acid esters.

  The liquid crystalline compound contained in the composition for forming an optical functional layer used in the present invention only needs to have nematic regularity, smectic regularity, or cholesteric regularity, and is polymerizable as a liquid crystal contained in the optical functional layer. Either low molecular liquid crystal or high molecular liquid crystal may be used. In the liquid crystalline compound used in the present invention, liquid crystal molecules having a rod-like structure and a discotic structure are preferable.

  Examples of the liquid crystalline compound having an ethylenically unsaturated bond include liquid crystalline compounds having an acrylate group, a methacrylate group, and a vinyloxy group. For example, the liquid crystal described in JP 2000-98133 A and JP 2002-69450 A Can be preferably used.

  As an example of the liquid crystalline compound having an acrylate group, a methacrylate group, or a vinyloxy group, for example, those having the following general formulas (1) to (7) may be mentioned.

  Examples of the compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule include compounds represented by the following general formulas (8) to (9) as compounds having an acrylate group and a methacrylate group. Can be mentioned.

(R ₁ represents hydrogen or a methyl group, and l represents 0 or 1.
Z is a compound represented by the following general formula (10).

m and u are integers of 1/12, and r is an integer of 0 to 12. n, p, q, and t are 0 or 1. L represents none, —COO—, —OCO—, —N═N— or —C═C—. R _{3 to} R ₇ are hydrogen,

, —O (CH ₂ ) _v —O—W, or —O—CO—W, and at least one of R _{3 to} R ₇ is —O (CH ₂ ) _v —O—W, or —O—. CO-W. v is an integer of 1-12. W is selected from structures represented by the following formulas.

R _{8 to} R ₁₈ represent hydrogen, halogen, CN group, alkyl group, alkyloxy group such as methoxy group, or a group obtained by fluorinating them, and R ₁₉ and R ₂₀ are alkyl groups such as methyl group and ethyl group. Or a group obtained by fluorinating them. )

  Of the compounds having a photodimerizable group and an ethylenically unsaturated bond in one molecule represented by the formulas (8) and (9), examples of the liquid crystalline compound include 4′-cinnamoyl-4-biphenylyl. Roxyethyl acrylate, 4'-cinnamoyl-4-biphenylyloxyhexyl acrylate, 7- [4- (6- (methacryloyloxy) hexyloxy) benzoyloxy] coumarin, 4-methoxy-phenyl 4- [6- (2- (Methacryloyloxy) hexyloxy] benzoate, (E) -5- [4- (2-methoxycarbonylvinyl) benzoyloxy] -2- (4-propylbenzoyloxy) benzoic acid 11- (2-methacryloyloxy) undecyl ester Etc.

  The mass ratio of the liquid crystal compound to the non-liquid crystal compound in the composition for forming an optical functional layer is preferably 60/40 or more and 100/0 or less. When the mass ratio of the liquid crystal compound to the non-liquid crystal compound is less than 60/40, the alignment of the liquid crystal compound is disturbed and the haze is increased.

  In the composition for forming an optical functional layer used in the present invention, in addition to the above components, additives such as a solvent, a photopolymerization initiator, a surfactant, a leveling agent, and a polymerization inhibitor can be used.

Photopolymerization initiator:
The composition for forming an optical functional layer according to the present invention contains a photopolymerization initiator. The photopolymerization initiator is appropriately selected from a radical photopolymerization initiator, a photocationic polymerization initiator, and the like according to the type and amount of the polymerizable group of the liquid crystalline compound or the non-liquid crystalline compound.

  Examples of the radical photopolymerization initiator include benzyl, benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, benzylmethyl ketal, dimethylaminomethylbenzoate, 2 -N-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3'-dimethyl-4-methoxybenzophenone, methylobenzoyl formate, 2-methyl-1- (4- (methylthio) phenyl ) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecylphenyl) -2-hydroxy- 2-me Rupropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1- On, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-proxythioxanthone Can do. In addition to the photopolymerization initiator, a sensitizer can be added within a range that does not impair the object of the present invention.

Photocationic polymerization initiators include sulfonic acid esters, imide sulfonates, dialkyl-4-hydroxysulfonium salts, arylsulfonic acid-p-nitrobenzyl esters, silanol-aluminum complexes, (η ⁶ -benzene) (η ⁵ -cyclopenta Dienyl) iron (II) and the like are exemplified, and more specifically, benzoin tosylate, 2,5-dinitrobenzyl tosylate, N-tosiphthalimide and the like are exemplified, but not limited thereto. .

  Examples of photo radical polymerization initiators and photo cationic polymerization initiators include aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, triazine compounds, iron arene complexes, etc. More specifically, diphenyliodonium, ditolyliodonium, iodonium chloride such as bis (p-tert-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium, bromide, borofluoride, hexafluorophosphate salt, Iodonium salts such as hexafluoroantimonate salt, chlorides of sulfonium such as triphenylsulfonium, 4-tert-butyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, bromide, borofluoride, hex Sulfonium salts such as fluorophosphate salts and hexafluoroantimonate salts, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1, 2,4,6-substituted-1,3,5 triazine compounds such as 3,5-triazine, 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, etc. It is not limited to these.

  The addition amount of such a photopolymerization initiator is generally 0.01 to 20% by mass, preferably 0.1 to 10% by mass with respect to the photopolymerizable component in the composition for forming an optical functional layer. %, More preferably in the range of 0.5 to 5% by mass.

solvent:
The solvent used in the composition for forming an optical functional layer is not particularly limited as long as the liquid crystalline compound is dissolved and the orientation of the photo-alignment film is not impaired. Specifically, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; hydrocarbons such as benzene and hexane; ethers such as tetrahydrofuran and 1,2-dimethoxyethane; alkyl halides such as chloroform and dichloromethane; methyl acetate , Esters such as ethyl acetate, propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate; glymes such as diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; amides such as N, N-dimethylformamide; sulfoxides such as dimethyl sulfoxide; Etc.

<Photo alignment film>
The photo-alignment film in the present invention is an alignment film capable of expressing an alignment regulating force by a photo-alignment method using a photodimerization reaction. The composition for forming a photo-alignment film used for forming the photo-alignment film in the optical element of the present invention is applied on a base material or a barrier layer formed on the base material and irradiated with light. By causing a photodimerization reaction and curing, an alignment regulating force is generated.

  The photo-alignment film in the present invention is formed using a composition for forming a photo-alignment film containing a compound having a group capable of photodimerization.

  Examples of the photodimerization compounds include compounds having cinnamic acid derivatives, coumarins, chalcones, benzylidenephthalimidines, benzylideneacetophenones, diphenylacetylenes, stilbazoles, styrylpyridiniums, uracils, quinolinones, maleimides or cinnamylidene acetic acid derivatives, Polymers having groups capable of photodimerization are preferred. In particular, a (meth) acrylic polymer or a maleimide polymer having a cinnamic acid derivative, coumarin, or chalcone in the side chain is preferably used (for example, JP-A-9-118717, JP10-506420A, Special Table). 2003-505561).

  Examples of units containing a photodimerizable group in the polymer preferably used in the present invention are shown in the following formulas.

(Z is a compound represented by the general formula (10).)

<Support>
The type of the support is determined according to the intended use of the optical element, but generally a transparent polymer film, a transparent glass plate or the like is used. Transparent means that the transmittance is 80% or more. An optically isotropic polymer film is generally used as the transparent polymer film, and examples thereof include a cellulose film such as triacetyl cellulose, a film made of a cycloolefin polymer, and a norbornene polymer.

  Depending on the type of liquid crystal display mode, an optically anisotropic polymer film may be used as the transparent support. As the optically anisotropic polymer film, polycarbonate, polysulfone, polyethersulfone, polyetheretherketone, poly (meth) acrylate, cycloolefin-based polymer, norbornene-based polymer, cellulose ester, or the like is used. An optically anisotropic polymer film is generally obtained by stretching. An optically anisotropic cellulose ester film can be obtained by using a retardation increasing agent, lowering the oxidation degree of cellulose acetate, and producing the film by a cooling dissolution method.

The thickness of the support is preferably 20 μm to 500 μm.
In order to improve the adhesion between the support and the alignment film, the support may be subjected to surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet treatment, flame treatment) to form a barrier layer described later. May be.

<Barrier layer>
The barrier layer blocks the entry of substances from the support to prevent the plasticizer and other substances contained in the support from entering the photo-alignment film and disturbing the alignment performance when the support is plastic. Is to do. The barrier layer is a layer obtained by curing a barrier layer-forming resin composition made of ultraviolet ray and / or electron beam curable resin by ultraviolet ray or electron beam irradiation in that it blocks the intrusion of substances from the support. preferable.

  A resin composition for forming a barrier layer comprising an ultraviolet ray or an electron beam curable resin has two polymerizable groups such as a polymerizable vinyl group, allyl group, acryloyl group, methacryloyl group, isopropenyl group, epoxy group, and oxetane group. What has the above and forms a crosslinked structure or network structure by irradiation to an ultraviolet-ray or an electron beam is preferable.

  Of these active groups, an acryloyl group, a methacryloyl group or an epoxy group is preferred from the viewpoint of polymerization rate and reactivity, and a polyfunctional monomer or oligomer is preferred. Examples include ultraviolet curable polyol acrylates, epoxy acrylates, urethane acrylates, polyester acrylates, and epoxy resins. These resins are usually used together with known photopolymerization initiators. The photopolymerization initiator or photosensitizer contained in the ultraviolet and / or electron beam curable resin composition excluding the solvent component that volatilizes after coating and drying is particularly preferably 0.5 to 5% by mass of the composition. preferable.

  Among these, ultraviolet curable polyol acrylate is particularly preferable in terms of adhesion to the photo-alignment film. Specific examples of the polyol acrylate include monofunctional acrylates and methacrylates such as polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, Methylolethane (tri) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, hexanediol di (meth) acrylate, tri Methylolpropane tri (acryloyloxypropyl) ether, tri (acryloyloxyethyl) isocyanurate, di (acrylo) Ruokishiechiru) isocyanurate, may be mentioned polyfunctional alcohol after adding ethylene oxide or propylene oxide (meth) were acrylated such as glycerin and trimethylol ethane.

  The film thickness after curing of the layer obtained by curing the ultraviolet ray and / or electron beam curable resin by ultraviolet ray or electron beam irradiation is suitably 0.05 μm or more and 30 μm or less, and preferably 0.1 to 15 μm. If the dry film thickness is too thick, the optical element may curl when it is on the film.

  When the support is untreated triacetyl cellulose, it is an ultraviolet and / or electron beam curable resin containing at least pentaerythritol triacrylate, di (acryloyloxyethyl) isocyanurate, or 1,6-hexanediol diacrylate. It is preferable in terms of adhesion to the support.

<Method for manufacturing optical element>
Next, an example of a preferable method for producing the optical element of the present invention will be described. If necessary, a resin composition for forming a barrier layer is applied on a support, and a crosslinked structure or a network structure is formed by irradiation with ultraviolet rays or electron beams and cured. Next, the resin composition for forming a photo-alignment film is applied and dried, and a photo-alignment film in which an alignment regulating force is generated by irradiating ultraviolet rays, particularly polarized ultraviolet rays, is formed. Next, the optical functional layer-forming resin composition was applied, dried, heated to the liquid crystal phase formation temperature, and then polymerized by ultraviolet irradiation or heating, and the liquid crystal molecules were aligned by the alignment regulating force of the photo-alignment film. An optical functional layer is formed.

[Example 1]
(Preparation of barrier layer)
Pentaerythritol triacrylate (PET-30: trade name, manufactured by Nippon Kayaku Co., Ltd.) 40 parts by mass, photopolymerization initiator Irgacure 184 (trade name, manufactured by Ciba Specialty Chemicals) 2 parts by mass, methyl ethyl ketone 29 parts by mass, toluene 58 A solution consisting of parts by mass is bar-coated on a triacetylcellulose film (FT-T80UZ: trade name, manufactured by Fuji Photo Film Co., Ltd.), dried at 80 ° C. for 3 minutes, and then irradiated with a UV irradiation device (Fusion UV Systems Japan Co., Ltd.). A barrier layer having a film thickness of 1 μm was produced by irradiating with 30 mJ / cm ² of ultraviolet light in a nitrogen atmosphere using a light source: H bulb.

(Preparation of alignment film)
Poly [1- [2- [4-[(E) -2-methoxycarbonylvinyl] phenoxy] ethoxycarbonyl] -1-methylethylene] is dissolved in cyclopentanone to form a 2% solids solution. After coating with a wire bar on the barrier layer prepared in the above step, it was heated and dried with hot air at 80 ° C. for 2 minutes to obtain a film having a dry mass of 0.07 g / m ² . The sample was irradiated with 10 mJ / cm ^{2 of} 310 nm linearly polarized ultraviolet light.

(Formation of optical functional layer)
7 parts by mass of a polymerizable liquid crystalline compound represented by the following formula (11), 3 parts by mass of a compound A having a photodimerizable group and an acryloyl group in one molecule represented by the following formula (12), Irgacure 907 (product) 0.5 parts by mass (manufactured by Ciba Specialty Chemicals Co., Ltd.) was dissolved in a mixed solvent of methyl ethyl ketone / toluene = 1/3 to obtain a solution for preparing an optical functional layer as a 10% solid content solution. This solution was coated on the photo-alignment film prepared in the above step with a wire bar, heated at 50 ° C. for 1 minute, and further heated at 95 ° C. for 2 minutes to align the liquid crystal, and then the UV irradiation device (fusion UV) The coating film was cured by irradiating 300 mJ / cm ² of ultraviolet light under a nitrogen atmosphere using a system Japan Co., Ltd. light source: H bulb. Thereby, a nematic liquid crystal layer was formed on the alignment film, and finally the optical element according to Example 1 was manufactured.

(Evaluation of adhesion)
A cross cut test according to JIS-K-5400 was performed. Specifically, 11 cuts were made vertically and horizontally at intervals of 1 mm on the coated surface of the nematic liquid crystal layer to make 100 1 mm square grids. A cellophane tape was affixed on this and peeled off quickly at an angle of 90 degrees. The number of grids remaining without peeling was 80, and the adhesion was excellent.

(Evaluation of haze)
Since this optical element is used for a display, a low haze value is required. The haze value tends to increase when the orientation of the liquid crystal layer is poor. When the haze value was measured with a turbidimeter NDH2000 (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.), the haze value was as good as 0.4%.

[Example 2]
5 parts by mass of a polymerizable liquid crystalline compound represented by the formula (11), 5 parts by mass of a compound A having a photodimerizable group and an acryloyl group in one molecule represented by the formula (12), Irgacure 907 (trade name, (Ciba Specialty Chemicals) 0.5 parts by mass is dissolved in a mixed solvent of methyl ethyl ketone / toluene = 1/3, and a 10% solid content solution is used as an optical functional layer preparation solution in the same manner as in Example 1 above. An optical element was prepared, and adhesion and haze were evaluated. The remaining grids without peeling off were 95 and the adhesion was good, but the haze value was as high as 2%.

Example 3
7 parts by mass of a polymerizable liquid crystalline compound represented by the formula (11), 3 parts by mass of a compound B having an acryloyl group and a photodimerizable group represented by the following formula (13), Irgacure 907 (trade name) The same as Example 1 except that 0.5 parts by mass is dissolved in a mixed solvent of methyl ethyl ketone / toluene = 1/3 and a 10% solid content solution is used as a solution for preparing an optical functional layer. Thus, an optical element was produced, and adhesion and haze were evaluated. The 80 grids remaining without peeling off had good adhesion, and the haze value was also good at 0.4%.

[Comparative Example 1]
10 parts by mass of the polymerizable liquid crystalline compound represented by the formula (11) and 0.5 part by mass of Irgacure 907 (trade name, manufactured by Ciba Specialty Chemicals) are dissolved in a mixed solvent of methyl ethyl ketone / toluene = 1/3 to obtain a solid. An optical element was prepared in the same manner as in Example 1 except that a 10% solution was used as a solution for preparing an optical functional layer, and adhesion and haze were evaluated. The number of grids remaining without peeling was zero and the adhesion was poor. The haze value was as good as 0.3%.

  The optical element of the present invention is excellent in durability because of excellent adhesion between the photo-alignment film and the optical functional layer. The optical element of the present invention is useful for, for example, a retardation plate, a polarizer, a color filter for display, and the like.

It is a figure which shows one example of the basic layer structure of the optical element of this invention. It is a figure which shows another example of the fundamental layer structure of the optical element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support body 2 Optical alignment film 3 Optical function layer 4 Barrier layer

Claims (5)

An optical element including at least a support, a photo-alignment film, and an optical functional layer,
The photo-alignment film is formed using a composition for forming a photo-alignment film containing a compound having a photodimerizable group,
The optical functional layer is formed using a composition for forming an optical functional layer, and the composition for forming an optical functional layer includes one or more compounds, and can be photodimerized in any compound. An optical group having at least one of a group, an ethylenically unsaturated bond, and liquid crystallinity, and having a photodimerizable group, an ethylenically unsaturated bond, and liquid crystallinity as a whole composition element.   The optical element according to claim 1, wherein the composition for forming an optical functional layer contains a liquid crystalline compound having a group capable of photodimerization and an ethylenically unsaturated bond in one molecule.   2. The optical functional layer forming composition according to claim 1, comprising a compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule, and a liquid crystalline compound having a plurality of ethylenically unsaturated bonds. Optical element.   The optical element according to claim 3, wherein the compound having a photodimerizable group and an ethylenically unsaturated bond in one molecule is further liquid crystalline.   The optical element according to claim 1, further comprising a barrier layer between the support and the photo-alignment film.