JP6960481B2 - Polymerizable liquid crystal composition and optical film - Google Patents

Description

The present invention relates to polymerizable liquid crystal compositions and optical films.

Optical films such as a polarizing film and a retardation film are used in the liquid crystal display device. Further, it is known that such an optical film is produced by using, for example, a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, a photopolymerization initiator and a solvent (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2008-547062

With conventionally known polymerizable liquid crystal compositions, it has not always been easy to produce an optical film in which a horizontally oriented smectic phase is formed.

The present invention provides the following [1] to [8].
[1] Containing a polymerizable liquid crystal compound showing a smectic phase, a leveling agent and a solvent.
The leveling agent is at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component.
A polymerizable liquid crystal composition in which the content of the leveling agent is 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound.

[2] The polymerizable liquid crystal compound according to [1], wherein the polymerizable liquid crystal compound has a temperature showing a nematic phase within a temperature range between a temperature showing a smectic phase and a temperature showing an isotropic phase. Polymerizable liquid crystal composition.
[3] The polymerizable liquid crystal composition according to [1] or [2], which further comprises a dichroic dye.
[4] An optical film obtained by polymerizing the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition according to any one of [1] to [3].

[5] A method for producing an optical film, which comprises the steps (1) to (3).
(1) The liquid crystal phase forms the coating film obtained in the steps (2) and (1) of applying the polymerizable liquid crystal composition according to any one of [1] to [3] on a substrate to obtain a coating film. Steps of converting to a film (3) A step of polymerizing a polymerizable liquid crystal compound contained in the film formed by the liquid crystal phase obtained in (2) to obtain an optical film.

[6] The production method according to [5], wherein the liquid crystal phase is a smectic phase.
[7] The coating film obtained in (1) above is heated to a temperature at which the polymerizable liquid crystal compound contained in the coating film exhibits a nematic phase or higher, and then the polymerizable liquid crystal compound is smectic. The production method according to [5] or [6], which is a step of converting the coating film into a film in which a smectic phase is formed by cooling the coating film to a temperature indicating a phase.
[8] An optical film obtained by the production method according to any one of [5] to [7].
[9] A display device including the optical film according to [4] or [8].

According to the polymerizable liquid crystal composition of the present invention, an optical film having a horizontally oriented smectic phase formed can be easily obtained. An optical film in which a horizontally oriented smectic phase is formed is particularly excellent in a two-color ratio.

It is the schematic which shows the liquid crystal display device 10 of this invention. It is the schematic which shows the liquid crystal display device 24 of this invention. It is the schematic which shows the EL display device 30 of this invention. It is the schematic which shows the EL display device 44 of this invention. It is the schematic which shows the projection type liquid crystal display device of this invention.

As described above, the polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound exhibiting a smectic phase, a specific leveling agent, and a solvent. Further, the leveling agent is at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component, and the content of the leveling agent is polymerization. It is 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the sex liquid crystal compound.

The optical film is a film that can transmit light and has an optical function. The optical function means absorption, reflection, diffraction, scattering, refraction, birefringence and the like. A retardation film, which is a kind of optical film, is used for converting linearly polarized light into circularly polarized light or elliptically polarized light, and conversely, converting circularly polarized light or elliptically polarized light into linearly polarized light.
A polarizing film, which is a type of optical film, is used to decompose unpolarized incident light into two orthogonal polarizing components, transmit one polarizing component, and absorb the other polarizing component. .. The axial direction of the transmitting polarized light component is called the transmission axis, and the axial direction of the absorbing polarizing component is called the absorption axis.

In a conventional polymerizable liquid crystal composition (for example, the polymerizable liquid crystal composition described in Patent Document 1), when the polymerizable liquid crystal composition is applied on an alignment film, the polymerizable liquid crystal contained in the polymerizable liquid crystal composition is contained. When the compound is a film showing a smectic phase (a film on which a liquid crystal phase is formed) and then the polymerizable liquid crystal compound is polymerized to obtain an optical film, the polymerizable liquid crystal compound in the film on which the liquid crystal phase is formed. It is difficult to obtain an optical film having an excellent two-color ratio, for example, because the liquid crystal tends to be oriented in the film thickness direction. Therefore, it is necessary to prepare a cell in which two alignment films face each other, which causes a problem that the operation is complicated. According to the polymerizable liquid crystal composition of the present invention, in the film formed by coating the liquid crystal phase, the polymerizable liquid crystal compound can be sufficiently oriented in the horizontal direction (film surface direction), resulting in two. An optical film or the like having an excellent color ratio can be obtained.

The polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound. The polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting liquid crystallinity. The polymerizable group means a group involved in the polymerization reaction of the polymerizable liquid crystal compound.
The polymerizable liquid crystal compound is a polymerizable liquid crystal compound exhibiting a smectic phase, and is a polymerizable liquid crystal having a temperature exhibiting a nematic phase within a temperature range between a temperature exhibiting a smectic phase and a temperature exhibiting an isotropic phase. It is preferably a compound. When the polymerizable liquid crystal compound is such a compound, a horizontally oriented smectic phase tends to be easily obtained.

Having a temperature indicating a nematic phase within a temperature range between a temperature indicating a smectic phase and a temperature indicating an isotropic phase means that the temperature indicating the smectic phase is Ts (° C.) and the temperature indicating the isotropic phase is defined as Ts (° C.). Equation (T1), where Ta (° C.) and the temperature indicating the nematic phase are Tn (° C.).
Ts <Tn <Ta (T1)
It means to satisfy the relationship of.

The smectic phase is selected from smectic A phase, smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase and smectic K phase. The smectic phase is inclined. Among them, the smectic B phase, the smectic F phase, the smectic I phase, the inclined smectic F phase and the inclined smectic I phase are preferable, and the smectic B phase is more preferable. When the liquid crystal phase (smetic phase) represented by the polymerizable liquid crystal compound is these liquid crystal phases, an optical film having a high degree of orientation order can be obtained.

Examples of the polymerizable liquid crystal compound include a compound represented by the formula (1) (hereinafter, may be referred to as “compound (1)”).

U ^1- V ^1- W ^1- X ^1- Y ^1- X ^2- Y ^2- X ^3- W ^2- V ^2- U ² (1)

[In formula (1), X ¹ , X ² and X ³ represent a p-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. .. However ^{, at least one of X 1} , X ² and X ³ represents a p-phenylene group which may have a substituent.
Y ¹ and ^{Y 2,} independently of one _{another, -CH 2 CH 2 -, -} CH 2 O -, - COO -, - OCOO-, a single ^{bond, -N = N -, - CR} a = CR b -, - It represents C≡C− or −CR ^a = N−. Represents.
R ^a and R ^b independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
U ¹ represents a hydrogen atom or a polymerizable group.
U ² represents a polymerizable group.
W ¹ and W ² independently represent a single bond, -O-, -S-, -COO- or -OCOO-.
V ¹ and V ² represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent independently of each other, and −CH ₂ − contained in the alkanediyl group is −O−, −. It may be replaced with S- or -NH-. ]

X ¹ , X ² and X ³ are p-phenylene groups which may have substituents or cyclohexane-1,4-diyl groups which may have substituents independently of each other. .. However, ^{at least one of X 1} , X ² and X ³ is a 1,4-phenylene group which may have a substituent.
It is preferable that at least two of X ¹ , X ² and X ³ are p-phenylene groups which may have a substituent.
The p-phenylene group is preferably unsubstituted. The cyclohexane-1,4-diyl group is preferably a trans-cyclohexane-1,4-diyl group, and more preferably these are unsubstituted.

The substituent that the p-phenylene group may have is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group; a cyano group; a halogeno group such as a fluoro group, a chloro group and a bromo group. And so on.
Examples of the substituent that the cyclohexane-1,4-diyl group may have include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group; a cyano group; a fluoro group and a chloro group. Examples thereof include a halogeno group such as a bromo group. _{-CH 2- of the} cyclohexane-1,4-diyl group may be substituted with -O-, -S- or -NR-. R is an alkyl group or a phenyl group having 1 to 6 carbon atoms.

Y ¹ and ^{Y 2,} independently of one _{another, -CH 2 CH 2 -, -} CH 2 O -, - COO -, - OCOO-, a single ^{bond, -N = N -, - CR} a = CR b -, - C≡C− or −CR ^a = N−. The bonding position of these groups may be in any direction.
R ^a and R ^b are hydrogen atoms or alkyl groups having 1 to 4 carbon atoms independently of each other. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a butyl group and the like.
Y ¹ is _{preferably −CH 2} CH _2- , −COO− or a single bond.
Y ² is _{preferably −CH 2} CH ₂ − or −CH ₂ O−.

U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. U ² is a polymerizable group. Both U ¹ and U ² are preferably photopolymerizable groups. Here, the photopolymerizable group refers to a group that can participate in polymerization by active radicals, acids, etc. generated from the photopolymerization initiator. Further, U ¹ and U ² are preferably groups of the same type.
Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

V ¹ and V ² are alkanediyl groups having 1 to 20 carbon atoms which may have substituents independently of each other, and −CH ₂ − contained in the alkanediyl group is −O−, −. It may be replaced with S- or -NH-.
The alkanediyl group having 1 to 20 carbon atoms includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decan-1,10-diyl group, tetradecane-1,14-diyl group and icosan Examples thereof include a -1,20-diyl group, preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.
Examples of the substituent that the alkanediyl group may have include a cyano group; a halogeno group such as a fluoro group, a chloro group, and a bromo group.
The alkanediyl group is preferably an unsubstituted alkanediyl group, and more preferably an unsubstituted linear alkanediyl group.

W ¹ and W ² are independent of each other, single-bonded, -O-, -S-, -COO- or -OCOO-, preferably single-bonded or -O-.

Examples of the compound (1) include compounds represented by the formulas (1-1) to (1-21). In the formula, the cyclohexane-1,4-diyl group is preferably a trans form.

The content of the compound (1) in the polymerizable liquid crystal composition of the present invention is preferably in the range of 70 to 99.9% by mass, more preferably in the range of 90 to 99.9% by mass, based on the solid content of the composition. preferable. Within the above range, the orientation of the compound tends to be high. Here, the solid content means the total amount of the components excluding the solvent from the composition. Compound (1) may be used alone or in combination of two or more.

The polymerizable liquid crystal composition of the present invention contains a leveling agent. The leveling agent has a function of adjusting the fluidity of the polymerizable liquid crystal composition and flattening the applied film, and examples thereof include a surfactant. The leveling agent contained in the polymerizable liquid crystal composition of the present invention is at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. By containing such a leveling agent, the polymerizable liquid crystal composition of the present invention states that when a film on which the above-mentioned liquid crystal phase is formed is obtained, the polymerizable liquid crystal compound is oriented in the horizontal direction in the film. The inventor found. The manifestation of such an effect cannot be easily recalled from the conventional polymerizable liquid crystal composition, and is based on the original knowledge of the present inventor.

Examples of the leveling agent containing a polyacrylate compound as a main component include BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK-361N, BYK-380, BYK-381, BYK. -392 (trade name: manufactured by BYK Chemie) and the like can be mentioned.

Examples of the leveling agent containing a fluorine atom-containing compound as a main component include Megafuck (trade name) R-08, R-30, R-90, F-410, F-411, F-443, and the same. F-445, F-470, F-471, F-477, F-479, F-482, F-483 (all manufactured by DIC Co., Ltd.), Surflon (trade name) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.), products Names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), Ftop (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) and the like can be mentioned.

The content of the leveling agent in the polymerizable liquid crystal composition of the present invention is 0.3 parts by mass or more and 5 parts by mass or less, preferably 0.5 parts by mass or more and 3 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. It is less than a part. The polymerizable liquid crystal composition of the present invention contains a specific leveling agent in a larger amount than usual, thereby enabling the production of an optical film in which a horizontally oriented smectic phase is formed. When the content of the leveling agent is within the above range, it is easy to horizontally orient the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition, and the obtained optical film tends to be smooth. If the content of the leveling agent exceeds 5 parts by mass, the obtained optical film tends to be uneven. Two or more of these leveling agents may be used in combination. When two or more kinds of leveling agents are used in combination, the total content thereof may be within the above range.

The polymerizable liquid crystal composition of the present invention may contain a dichroic dye. When the polymerizable liquid crystal composition of the present invention is a composition containing a polymerizable liquid crystal compound, a dichroic dye, a leveling agent and a solvent, the obtained optical film has a function as a polarizing film. The dichroic dye refers to a dye having a property in which the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different.

The dichroic dye is not particularly limited and may be a dye or a pigment. The dichroic dye preferably has a maximum absorption wavelength of 300 to 700 nm. Examples of the dichroic pigment include an acridine pigment, an oxazine pigment, a cyanine pigment, a naphthalene pigment, an azo pigment, an anthraquinone pigment and the like. The dichroic dye may be used alone or in combination of a plurality of dichroic dyes.

As the dichroic dye, an azo dye is preferable. Examples of the azo dye include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a stilbene azo dye, and the like, and a bisazo dye and a trisazo dye are preferable.

Hereinafter, specific examples of the dichroic dye that can be used in the polymerized liquid crystal composition of the present invention will be shown.
Examples of the azo dye include a compound represented by the formula (2).
A ¹ (-N = ^{NA 2} ) _p -N = NA ³ (2)
[In the formula (2), A ¹ and A ³ may independently have a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. Represents a good monovalent heterocyclic group. A ² may independently have a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a substituent 2 Represents a valent heterocyclic group. p represents an integer of 1 to 4. When p is an integer of 2 or more, the plurality of A ^2s may be the same or different from each other. ]

The monovalent heterocyclic group is a group obtained by removing one hydrogen atom from a heterocycle such as a quinoline ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an imidazole ring, a benzimidazole ring, an oxazole ring, or a benzoxazole ring. Can be mentioned. Further, examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the above heterocycle.

It may have a phenyl group, a naphthyl group and a monovalent heterocyclic group in ^{A 1} and A ^3, and a p-phenylene group, a naphthalene-1,4-diyl group and a divalent heterocyclic group in ^{A 2.} Examples of the substituent include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group and a butoxy group; and a carbon such as a trifluoromethyl group. Alkyl fluoride group of number 1 to 4; cyano group; nitro group; halogeno group such as fluoro group, chloro group, bromo group; amino group; substituted with alkyl group having 1 to 4 carbon atoms such as diethylamino group and pyrrolidino group. Amino group (two alkyl groups substituted with an amino group may be bonded to each other to form an alcandiyl group having 2 to 8 carbon atoms).

As the azo dye, compounds represented by the following formulas (2-1) to (2-6) are preferable. In formulas (2-1) to (2-6), B ^{1 to} B ²⁰ are hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, cyano groups, nitro groups, and aminos. A group, an amino group substituted with an alkyl group having 1 to 4 carbon atoms (two alkyl groups substituted with an amino group may be bonded to each other to form an alkylandyl group having 2 to 8 carbon atoms), Represents a chloro group or a trifluoromethyl group. Each of n1 to n4 independently represents an integer of 0 to 3. If n1 is an integer of 2 or more, a plurality of ^{B 2} may be the same or different from each other, similarly when n2~n4 is an integer of 2 or more, a plurality of ^B 6, ^{B 9} and ^{B 14} are They may be the same or different from each other.

As the anthraquinone dye, a compound represented by the formula (2-7) is preferable.

[In formula (2-7), R ^{1 to} R ⁸ independently represent a hydrogen atom, -R ^x , an amino group, -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom. R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As the acridine dye, a compound represented by the formula (2-8) is preferable.

[In formula (2-7), R ^{9 to} R ¹⁵ independently represent a hydrogen atom, -R ^x , an amino group, -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom. R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As the oxazone dye, a compound represented by the formula (2-9) is preferable.

[In formula (2-9), R ^{9 to} R ¹⁵ independently represent a hydrogen atom, -R ^x , an amino group, -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom. R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

In the above equations (2-7), (2-8) and (2-9),
Examples of the alkyl group having 1 to 4 carbon atoms in R ^x include a methyl group, an ethyl group, a propyl group, a butyl group and the like.
Examples of the aryl group having 6 to 12 carbon atoms in R ^x include a phenyl group, a toluyl group, a xsilyl group, a naphthyl group and the like.

As the cyanine dye, a compound represented by the formula (2-10) and a compound represented by the formula (2-11) are preferable.

ｎ５は１〜３の整数を表す。］ [In the formula (2-10), D ¹ and D ² independently represent the groups represented by the formulas (2-10a) to (2-10d).

n5 represents an integer of 1 to 3. ]

ｎ６は１〜３の整数を表す。］ [In the formula (2-11), D ³ and D ⁴ independently represent the groups represented by the formulas (2-11a) to (2-11h).

n6 represents an integer of 1 to 3. ]

When the polymerizable liquid crystal composition of the present invention contains a dichroic dye, the content thereof is preferably 50 parts by mass or less, and 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound. More preferably, it is 0.1 part by mass or more and 10 parts by mass or less. Within the above range, the polymerizable liquid crystal compound can be polymerized without disturbing the orientation. If the content of the dichroic dye exceeds 50 parts by mass, the orientation of the polymerizable liquid crystal compound may be disturbed, which is not preferable.

The polymerizable liquid crystal composition of the present invention contains a solvent. As the solvent, a component other than the solvent contained in the polymerizable liquid crystal composition, for example, a solvent capable of dissolving the polymerizable liquid crystal compound is preferable. Moreover, it is preferable that the solvent is inert to the polymerization reaction of the polymerizable liquid crystal composition.
Solvents include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone. Or ester solvents such as propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; toluene And aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; and the like. These solvents may be used alone or in combination of two or more.

The content of the solvent in the polymerizable liquid crystal composition of the present invention is preferably 50 to 98% by mass with respect to the total amount of the polymerizable liquid crystal composition. In other words, the solid content of the polymerizable liquid crystal composition of the present invention is preferably 2 to 50% by mass. When the solid content is 2% by mass or more, the film thickness of the obtained optical film is not too thin, and as a result, the optical film can obtain the dichroism required for the polarizer. Further, when the solid content is 50% by mass or less, the viscosity of the polymerizable liquid crystal composition of the present invention is low, so that the film thickness of the coating film tends to be less likely to be uneven in the production of the optical film described later. The solid content refers to the amount obtained by removing the solvent from the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention may contain a polymerization initiator. The polymerization initiator is a compound that initiates the polymerization of a polymerizable liquid crystal compound, and generates active radicals and acids by the action of light and / or heat. Of these, a polymerization initiator that generates active radicals or acids by the action of light (that is, a photopolymerization initiator) is preferable, and a photopolymerization initiator that generates radicals by light irradiation is more preferable.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts and sulfonium salts.

Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and the like.
Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3', 4,4'-tetra (tert-butylperoxycarbonyl). ) Benzophenone, 2,4,6-trimethylbenzophenone and the like.

Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl). ) Butane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1 -[4- (2-Hydroxyethoxy) phenyl] propane-1-one, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane-1- Examples include on oligomers.

Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and the like.
Examples of the triazine compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-triazine and 2,4-bis (trichloromethyl) -6- (4-methoxy). Naftyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (5-Methylfuran-2-yl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (fran-2-yl) ethenyl] -1 , 3,5-Triazine, 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino-2-methylphenyl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) Methyl) -6- [2- (3,4-dimethoxyphenyl) ethenyl] -1,3,5-triazine and the like can be mentioned.

Photopolymerization initiators include Irgacure 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (all manufactured by Ciba Japan Co., Ltd.), Sequol BZ, Sequol Z, Sequol BEE (or more). , All manufactured by Seiko Kagaku Co., Ltd., kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), ADEKA PTOMER SP-152 or ADEKA PTOMER SP-170 (above) , All of which are manufactured by ADEKA Corporation, TAZ-A, TAZ-PP (manufactured by Nippon Sibel Hegner) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.), and commercially available photopolymerization initiators can also be used.

Examples of the thermal polymerization initiator include azo compounds such as azobisisobutyronitrile; and peroxides such as hydrogen peroxide, persulfate, and benzoyl peroxide.

The content of the polymerization initiator is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, still more preferably 0.5 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. ..
Within the above range, the polymerizable liquid crystal compound can be polymerized without disturbing its orientation.

When a photopolymerization initiator is used as the polymerization initiator, a photosensitizer may be used in combination. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (eg, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene and anthracene such as alkoxy group-containing anthracene (eg, dibutoxyanthracene, etc.). Compounds; phenothiazines; rubrene and the like can be mentioned.

By using a photosensitizer, the polymerization of the polymerizable liquid crystal compound can be made highly sensitive.
When a photosensitizer is used, the amount used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and 0.5 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Parts by mass are even more preferred.

The polymerizable liquid crystal composition of the present invention may contain a polymerization inhibitor. When the polymerizable liquid crystal composition of the present invention contains a polymerization inhibitor, the polymerization of the polymerizable liquid crystal compound can be controlled, and the stability of the polymerizable liquid crystal composition of the present invention can be improved.

Examples of the polymerization inhibitor include hydroquinone, an alkoxy group-containing hydroquinone, an alkoxy group-containing catechol (for example, butylcatechol, etc.), pyrogallol, and a radical supplement such as 2,2,6,6-tetramethyl-1-piperidinyloxyradic. , Thiophenols, β-naphthylamines, β-naphthols and the like.
When the polymerizable liquid crystal composition of the present invention contains a polymerization inhibitor, the content thereof is preferably 0.1 to 30 parts by mass, and 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. More preferably, 0.5 to 8 parts by mass is further preferable. Within the above range, the polymerization can be controlled without disturbing the orientation of the polymerizable liquid crystal compound.

The optical film of the present invention can be obtained by polymerizing a polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition of the present invention.

The optical film of the present invention can be obtained by a production method including the following (1) to (3).
(1) Steps of applying the polymerizable liquid crystal composition of the present invention on a substrate to obtain a coating film (2) Steps of converting the coating film obtained in (1) into a film on which a liquid crystal phase is formed (3) ) A step of polymerizing the polymerizable liquid crystal compound contained in the film formed by the liquid crystal phase obtained in (2) to obtain an optical film.

Examples of the coating method on the substrate include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a die coating method, a dip coating method, a bar coating method and a spin coating method.

Examples of the substrate include glass, a plastic sheet, a plastic film, and a translucent film. The translucent film includes, for example, a polyolefin film made of polyolefin such as polyethylene, polypropylene, norbornene polymer; polyvinyl alcohol film; polyethylene terephthalate film; polymethacrylic acid ester film; polyacrylic acid ester film; cellulose ester film; polyethylene. Examples thereof include naphthalate film; polycarbonate film; polysulphon film; polyether sulfone film; polyether ketone film; polyphenylene sulfide film and polyphenylene oxide film.
If an optical film is manufactured using a substrate, the obtained optical film can be easily handled without tearing when it is transported or stored.

In the method for producing an optical film of the present invention, it is preferable that an alignment film is formed on the substrate. In that case, the polymerizable liquid crystal composition of the present invention is applied on the alignment film. The alignment film preferably has solvent resistance that does not dissolve when the polymerizable liquid crystal composition of the present invention is applied. Further, it is preferable to have heat resistance in heat treatment for removing a solvent and aligning a liquid crystal display. Further, it is preferable that the alignment film does not peel off due to friction due to rubbing or the like. The alignment film is preferably made of an alignment polymer.

Examples of the oriented polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule, and polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and poly, which are hydrolysates thereof. Polymers such as oxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylic acid esters can be mentioned. Among these, polyvinyl alcohol is preferable. These oriented polymers forming the alignment film may be used alone or in combination of two or more. Further, the oriented polymer may be a copolymer having a plurality of types of structural units constituting the illustrated oriented polymer. These oriented polymers can be easily obtained by polycondensation by dehydration or deamine, chain polymerization such as radical polymerization, anionic polymerization and cationic polymerization, coordination polymerization and ring-opening polymerization.

The oriented polymer can form an oriented film on the substrate by applying the oriented polymer composition (a solution containing the oriented polymer) dissolved in a solvent onto the substrate. The solvent used for the oriented polymer composition is not particularly limited, but specifically, water; an alcohol solvent such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve and propylene glycol monomethyl ether. ; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone Solvents; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-substituted carbides such as chloroform and chlorobenzene Hydrogen solvent; etc. These organic solvents may be used alone or in combination of two or more.

Further, as the alignment polymer composition for forming the alignment film, a commercially available alignment film material may be used as it is. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

As a method of forming an alignment film on the base material, for example, the orientation polymer composition or a commercially available alignment film material is applied onto the base material, and then annealed to align the alignment film on the base material. A film can be formed. The thickness of the alignment film thus obtained is, for example, 10 nm to 10000 nm, preferably 10 nm to 1000 nm.

In order to impart an orientation regulating force to the alignment film, it is preferable to perform rubbing or polarized UV irradiation as necessary. By imparting an orientation regulating force, the polymerizable liquid crystal compound can be oriented in a desired direction.

As a method of rubbing the alignment film, for example, a rubbing cloth is wound around the rubbing roll, a rotating rubbing roll is prepared, and the alignment film formed on the base material is placed on a stage and the rotating rubbing roll is placed. A method of bringing the rotating rubbing roll into contact with the alignment film by transporting the film toward the surface can be mentioned. Further, by irradiating the alignment film with polarized light (preferably polarized UV), an orientation regulating force may be imparted to the alignment film. When masking is performed during rubbing or polarized UV irradiation, it is possible to form a plurality of regions (patterns) having different orientation directions.

With respect to the coating film obtained by applying the polymerizable liquid crystal composition of the present invention on a substrate or an alignment film formed on the substrate, volatility of a solvent or the like contained in the coating film is obtained in terms of film formation property. It is preferable to dry the sex component. Examples of the drying method include a natural drying method, a ventilation drying method, a vacuum drying method and the like. The drying temperature is preferably 0 to 250 ° C, more preferably 50 to 220 ° C. The drying time is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 30 minutes.

In order to convert the coating film into a film on which a liquid crystal phase is formed, the coating film may be heated to a temperature at which the polymerizable liquid crystal compound contained in the coating film exhibits a liquid crystal phase. The liquid crystal phase is preferably a smectic phase due to the action of the polymerizable liquid crystal compound.

In order for the polymerizable liquid crystal compound contained in the coating film to exhibit a smectic phase (to orient the polymerizable liquid crystal compound in the smectic phase), the coating film may be heated and then cooled. At that time, when the polymerizable liquid crystal compound satisfies the relationship of the above formula (T1), first, the temperature at which the polymerizable liquid crystal compound exhibits a nematic phase (Tn, in addition, this Tn is referred to as "nematic phase transition". It is more preferable to obtain a film formed by the liquid crystal phase by heating the coating film above the temperature (sometimes referred to as “temperature”) and then cooling to a temperature (Ts) at which the polymerizable liquid crystal compound exhibits a smectic phase.
When the polymerizable liquid crystal composition of the present invention contains two or more kinds of polymerizable liquid crystal compounds, a mixture prepared by adjusting the polymerizable liquid crystal compound according to the content ratio contained in the polymerizable liquid crystal composition is first prepared, and this mixture is prepared. By measuring the temperature indicating the liquid crystal phase, it is possible to determine the temperature conditions for producing an optical film from the polymerizable liquid crystal composition of the present invention containing two or more kinds of polymerizable liquid crystal compounds.

By passing through the nematic phase in this way, the leveling agent contained in the polymerizable liquid crystal composition of the present invention becomes more fluid, and a horizontally oriented film can be obtained more easily. The heating temperature for the polymerizable liquid crystal compound to exhibit the nematic phase is preferably in the range of the temperature above the nematic phase transition point and below 100 degrees above the nematic phase transition point, and above and below the nematic phase transition point and 50 degrees above the nematic phase transition point. Higher temperatures and below are more preferred. The operation of heating the coating film until it shows a nematic phase and the drying operation of removing the volatile component from the coating film may be performed at the same time.

Next, an optical film can be obtained by polymerizing the polymerizable liquid crystal compound contained in the film on which the liquid crystal phase is formed. By polymerizing the polymerizable liquid crystal compound, a durable optical film can be obtained. The polymerization method may be selected according to the type of the polymerizable group of the polymerizable liquid crystal compound. If the polymerizable group is a photopolymerizable group, it can be polymerized by a photopolymerization method, and if it is a thermopolymerizable group, it can be polymerized by a thermal polymerization method. In the method for producing an optical film of the present invention, a photopolymerization method is preferable. In the photopolymerization method, it is not always necessary to heat the substrate to a high temperature, so that a substrate having low heat resistance can be used. The photopolymerization method is carried out by irradiating the film on which the liquid crystal phase is formed with visible light, ultraviolet light or laser light. Ultraviolet light is preferable because it is easy to handle. Light irradiation is performed in a state where a liquid crystal phase is formed on the film. Light may be irradiated at a temperature indicating the liquid crystal phase as described above. At this time, the optical film can be patterned by masking or developing.

The optical film formed on the substrate may be peeled off from the substrate after the polymerizable liquid crystal compound contained in the film is polymerized. Further, in addition to the step of peeling the substrate, a step of peeling the alignment film may be further included. Thereby, a single-layer optical film of the present invention can be obtained. The film thickness of the optical film of the present invention is preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 0.5 to 5 μm. When the film thickness is within the above range, an optical film horizontally oriented in the smectic phase can be easily obtained.

When the optical film of the present invention contains a dichroic dye, it is useful as a polarizing film having an excellent dichroic ratio. Further, when it does not contain a dichroic dye, it is useful as a retardation film having excellent contrast.

The optical film of the present invention obtained as described above can be used in various display devices. The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, an electron emission display device (for example, an electric field emission display device (FED), and a surface electric field emission display device (SED). )), Electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, display device having a grating light valve (GLV) display device, digital micromirror device (DMD)), Examples of the liquid crystal display device include a piezoelectric ceramic display, a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection type liquid crystal display device, and the like. The display device may be a display device that displays a two-dimensional image, or may be a three-dimensional display device that displays a three-dimensional image.

FIG. 1 is a schematic view showing the liquid crystal display device 10 of the present invention. The liquid crystal layer 17 is sandwiched between two substrates 14a and 14b.

A color filter 15 is arranged on the liquid crystal layer 17 side of the substrate 14a. The color filter 15 is arranged at a position facing the pixel electrodes 22 across the liquid crystal layer 17, and the black matrix 20 is arranged at a position facing the boundary between the pixel electrodes. The transparent electrode 16 is arranged on the liquid crystal layer 17 side so as to cover the color filter 15 and the black matrix 20.
An overcoat layer may be provided between the color filter 15 and the transparent electrode 16.
The thin film transistor 21 and the pixel electrode 22 are regularly arranged on the liquid crystal layer 17 side of the substrate 14b. The pixel electrode 22 is arranged at a position facing the color filter 15 with the liquid crystal layer 17 in between. An interlayer insulating film 18 having a connection hole (not shown) is arranged between the thin film transistor 21 and the pixel electrode 22.

Examples of the substrate 14a and the substrate 14b include a glass substrate and a plastic substrate.
When the color filter 15 and the thin film transistor 21 formed on these substrates require a step of heating to a high temperature, a glass substrate is preferable.

Examples of the thin film transistor 21 include a high-temperature polysilicon transistor formed on a quartz substrate, a low-temperature polysilicon transistor formed on a glass substrate, and an amorphous silicon transistor formed on a glass substrate or a plastic substrate. A driver IC may be formed on the substrate 14b in order to reduce the size of the liquid crystal display device.

A liquid crystal layer 17 is arranged between the transparent electrode 16 and the pixel electrode 22. A spacer 23 is arranged on the liquid crystal layer 17 in order to keep the distance between the substrate 14a and the substrate 14b constant.
Of the layers formed on the substrate 14a and the substrate 14b, the alignment film for orienting the liquid crystal in a desired direction may be arranged on the surface in contact with the liquid crystal layer 17.
Each member is laminated in the order of the substrate 14a, the color filter 15 and the black matrix 20, the transparent electrode 16, the liquid crystal layer 17, the pixel electrode 22, the interlayer insulating film 18, the thin film transistor 21, and the substrate 14b.

On the outside of the substrate 14a and the substrate 14b sandwiching the liquid crystal layer 17, polarizing films (for example, linear polarizers) 12a and 12b and retardation films (for example, 1/4 wave plate or optical compensation film) are used as optical films. 13a and 13b are laminated in this order. At least one selected from the group consisting of the polarizing films 12a and 12b and the retardation films 13a and 13b is the optical film of the present invention. By arranging the optical film of the present invention, the liquid crystal display device 10 can be provided with a function of converting incident light into linearly polarized light or circularly polarized light and a function of optically compensating for a phase shift due to a liquid crystal display. The retardation films 13a and 13b may not be arranged depending on the structure of the liquid crystal display device and the type of the liquid crystal compound contained in the liquid crystal layer 17. An antireflection film 11 for preventing reflection of external light is arranged on the outside of the polarizing film 12a. According to the optical film of the present invention, the display device can be made thinner.
The optical film of the present invention, the alignment film, and the substrate used for producing the optical film are laminated as at least one selected from the group consisting of the polarizing films 12a and 12b and the retardation films 13a and 13b. You may use the body.

A backlight unit 19 which is a light emitting source is arranged on the outside of the polarizing film 12b. The backlight unit 19 includes a light source, a light guide body, a reflector, a diffusion sheet, and a viewing angle adjusting sheet. Examples of the light source include electroluminescence, cold cathode fluorescent lamp, hot cathode fluorescent lamp, light emitting diode (LED), laser light source, mercury lamp and the like. The polarizer of the present invention may be selected according to the characteristics of the light source.

When the liquid crystal display device 10 of the present invention is a transmissive liquid crystal display device, the white light emitted from the light source in the backlight unit 19 enters the light guide body, changes its course by the reflector, and diffuses by the diffusion sheet. Has been done. The diffused light is adjusted to have a desired directivity by the viewing angle adjusting sheet, and then is incident on the polarizing film 12b from the backlight unit 19.

Of the unpolarized incident light, only one linearly polarized light passes through the polarizing film 12b of the liquid crystal panel. This linearly polarized light is converted into circularly polarized light by the retardation film 13b, and sequentially passes through the substrate 14b, the pixel electrodes 22, and the like to reach the liquid crystal layer 17.

Here, the orientation state of the liquid crystal molecules contained in the liquid crystal layer 17 changes depending on the presence or absence of a potential difference between the pixel electrode 22 and the transparent electrode 16 facing the pixel electrode 22, and the brightness of the light emitted from the liquid crystal display device 10 is controlled. NS. When the liquid crystal layer 17 is in an oriented state in which the circularly polarized light converted by the retardation film 13b is transmitted as it is, the circularly polarized light is transmitted through the liquid crystal layer 17 and the transparent electrode 16, and light in a specific wavelength range is a color filter. When it passes through 15 to reach the retardation film 13a and further passes through the polarizing film 12a and the antireflection film 11, the liquid crystal display device displays the color determined by the color filter brightest.

On the contrary, when the liquid crystal layer 17 is in an oriented state in which the circularly polarized light converted by the retardation film 13b is converted and transmitted, the light transmitted through the liquid crystal layer 17, the transparent electrode 16 and the color filter 15 is the retardation film. It is absorbed by 13a and the polarizer 12a. As a result, this pixel displays black. In the orientation state between these two states, the brightness of the light emitted from the liquid crystal display device 10 is also intermediate between the two, so that this pixel displays an intermediate color.

When the liquid crystal display device 10 of the present invention is a transflective liquid crystal display device, the pixel electrode 22 has a transmissive portion made of a transparent material and a reflective portion made of a material that reflects light. , The image is displayed in the same manner as the above-mentioned transmissive liquid crystal display device. On the other hand, in the reflecting portion, external light enters the liquid crystal display device from the direction of the antireflection film 11, and the circularly polarized light transmitted through the polarizing film 12a and the retardation film 13a passes through the liquid crystal layer 17 and is reflected by the pixel electrode 22. It is used for display.

FIG. 2 is a schematic view showing a liquid crystal display device 24 in which an optical film is arranged inside a substrate (on the liquid crystal 17 side). In the liquid crystal display device 24, each member includes an antireflection film 11, a substrate 14a, a polarizing film 12a, a retardation film 13a, a color filter 15 and a black matrix 20, a transparent electrode 16, a liquid crystal layer 17, a pixel electrode 22, and an interlayer insulating film. The 18 and the thin film transistor 21, the retardation film 13b, the polarizing film 12b, the substrate 14b, and the backlight unit 19 are laminated in this order. At least one selected from the group consisting of the polarizing films 12a and 12b and the retardation films 13a and 13b is the optical film of the present invention. The laminated body may be used. By arranging the optical film of the present invention, the liquid crystal display device 24 can be provided with a function of converting incident light into linearly polarized light or circularly polarized light and a function of optically compensating for a phase shift due to a liquid crystal display. The retardation films 13a and 13b may not be arranged depending on the structure of the liquid crystal display device and the type of the liquid crystal compound contained in the liquid crystal layer 17.

FIG. 3 is a schematic view showing the EL display device 30 of the present invention. The EL display device 30 has an organic functional layer 36 as a light emitting source and a cathode electrode 37 laminated on a substrate 33 on which a pixel electrode 35 is formed. The retardation film 32 and the polarizing film 31 are arranged on the opposite side of the substrate 33 from the organic functional layer 36. At least one selected from the group consisting of the retardation film 32 and the polarizing film 31 is the optical film of the present invention. The organic functional layer 36 emits light by applying a positive voltage to the pixel electrode 35 and a negative voltage to the cathode electrode 37 and applying a direct current between the pixel electrode 35 and the cathode electrode 37. The organic functional layer 36, which is a light emitting source, is composed of an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, the retardation film 32, and the polarizing film 31. Although the organic EL display device having the organic functional layer 36 will be described, it may be applied to the inorganic EL display device having the inorganic functional layer.

In order to manufacture the EL display device 30 of the present invention, first, the thin film transistor 40 is formed on the substrate 33 in a desired shape. Then, the interlayer insulating film 34 is formed, and then the pixel electrode 35 is formed by a sputtering method and patterned. Then, the organic functional layer 36 is laminated.

Examples of the substrate 33 include a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, a ceramic substrate such as alumina, a metal substrate such as copper, and a plastic substrate. A heat conductive film may be formed on the substrate. Examples of the heat conductive film include a diamond thin film (DLC and the like). When the pixel electrode 35 is of the reflection type, light is emitted in the direction opposite to that of the substrate 33. Therefore, not only a transparent material but also a non-transparent material such as stainless steel can be used. The substrate may be formed as a single substrate, or a plurality of substrates may be bonded together with an adhesive to form a laminated substrate. These substrates are not limited to plates, but may be films.

As the thin film transistor 40, a normal polycrystalline silicon transistor may be used.
The thin film transistor 40 is provided at the end of the pixel electrode 35, and its size is about 10 to 30 μm. The size of the pixel electrode 35 is about 20 μm × 20 μm to 300 μm × 300 μm.

Wiring electrodes of the thin film transistor 40 are provided on the substrate 33. The wiring electrode has a low resistance and has a function of electrically connecting to the pixel electrode 35 to keep the resistance value low. Generally, the wiring electrode is Al, Al and a transition metal (excluding Ti), Ti or Those containing any one or more of titanium nitride (TiN) are used.

An interlayer insulating film 34 is provided between the thin film transistor 40 and the pixel electrode 35. The interlayer insulating film 34 is formed _{by forming an inorganic material such as silicon oxide such as SiO 2} or silicon nitride by sputtering or vacuum deposition, a silicon oxide layer formed by SOG (spin on glass), a photoresist, or polyimide. Any material having insulating properties, such as a coating film of a resin-based material such as acrylic resin, may be used.

The rib 41 is formed on the interlayer insulating film 34. The rib 41 is arranged in the peripheral portion (between adjacent pixels) of the pixel electrode 35. Examples of the material of the rib 41 include an acrylic resin and a polyimide resin. The thickness of the rib 41 is preferably 1.0 μm or more and 3.5 μm, and more preferably 1.5 μm or more and 2.5 μm or less.

Next, an EL element including a pixel electrode 35 which is a transparent electrode, an organic functional layer 36 which is a light emitting source, and a cathode electrode 37 will be described. The organic functional layer 36 has at least one hole transport layer and a light emitting layer, respectively, and has, for example, an electron injection transport layer, a light emitting layer, a hole transport layer, and a hole injection layer in that order.

Examples of the pixel electrode 35 include ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), IGZO, ZnO, SnO ₂ , In ₂ O _{3, and the} like, but ITO and IZO are particularly preferable. The thickness of the pixel electrode 35 may be a certain thickness or more capable of sufficiently injecting holes, and is preferably about 10 to 500 nm.
The pixel electrode 35 can be formed by a vapor deposition method (preferably a sputtering method). The sputter gas is not particularly limited, and an inert gas such as Ar, He, Ne, Kr, or Xe, or a mixed gas thereof may be used.

As a constituent material of the cathode electrode 37, for example, a single metal element such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, Zr, or stability is improved. It is preferable to use a two-component, three-component alloy system containing them. Examples of the alloy system include Ag · Mg (Ag: 1 to 20 at%), Al · Li (Li: 0.3 to 14 at%), In · Mg (Mg: 50 to 80 at%), Al · Ca (Ca:: 5 to 20 at%) and the like are preferable.
The cathode electrode 37 is formed by a vapor deposition method, a sputtering method, or the like. The thickness of the cathode electrode 37 is preferably 0.1 nm or more, preferably 1 to 500 nm or more.

The hole injection layer has a function of facilitating the injection of holes from the pixel electrode 35, and the hole transport layer has a function of transporting holes and a function of hindering electrons. Also called the transport layer.
The thickness of the light emitting layer, the combined thickness of the hole injection layer and the hole transport layer, and the thickness of the electron injection transport layer are not particularly limited and vary depending on the forming method, but may be about 5 to 100 nm. preferable. Various organic compounds can be used for the hole injection layer and the hole transport layer. It is preferable to use a vacuum vapor deposition method for forming the hole injection transport layer, the light emitting layer and the electron injection transport layer because a homogeneous thin film can be formed.

The organic functional layer 36, which is a light emitting source, uses light emission (phosphorescence) from a single-term exciter, one that uses light emission (phosphorescence) from a triple-term exciter, and one from a single-term excitator. Those that utilize luminescence (fluorescence) and those that utilize luminescence (phosphorescence) from triplet excitators, those that are formed by organic substances, those that are formed by inorganic substances, those that are formed by organic substances, and those that are formed by organic substances. Those containing those formed of inorganic substances, high molecular weight materials, low molecular weight materials, high molecular weight materials and low molecular weight materials, and the like can be used. However, the present invention is not limited to this, and an EL display device using various EL elements can be used.

A desiccant 38 is arranged in the space between the cathode electrode 37 and the sealing lid 39. This is because the organic functional layer 36 is vulnerable to humidity. Moisture is absorbed by the desiccant 38 to prevent deterioration of the organic functional layer 36.

The polarizing film 31 formed on the light incident surface or the light emitting surface of the EL display device 30 is not limited to the polarizing film that converts linearly polarized light, and may be a polarizing film that converts to elliptically polarized light. The polarizing film 31 may be the optical film of the present invention alone, or may be used by laminating a polarizing film or a retardation film other than the optical film of the present invention.

FIG. 4 is a schematic view showing the EL display device 44 of the present invention. The EL display device 44 has a sealing structure using a thin film sealing film 42, and can also obtain emitted light from the opposite surface of the array substrate.
As the thin film sealing film 42, it is preferable to use a DLC film in which DLC (diamond-like carbon) is vapor-deposited on the film of the electrolytic capacitor. The DLC film has extremely poor moisture permeability and high moisture-proof performance. Further, a DLC film or the like may be formed by directly vapor deposition on the surface of the cathode electrode 37. Further, the thin film sealing film 42 may be formed by laminating a resin thin film and a metal thin film in multiple layers.

FIG. 6 is a schematic view showing the projection type liquid crystal display device of the present invention.
The polarizing film 142 and the polarizing film 143 of the present invention are used, for example, in a projection type liquid crystal display device (projector).
The light flux emitted from the light source (for example, a high-pressure mercury lamp) 111, which is a light emitting source, first passes through the first lens array 112, the second lens array 113, the polarization conversion element 114, and the superimposed lens 115. Luminance is made uniform and polarized in the anti-ray bundle cross section.

Specifically, the ray bundle emitted from the light source 111 is divided into a large number of minute ray bundles by the first lens array 112 in which the minute lenses 112a are formed in a matrix. The second lens array 113 and the superimposed lens 115 are provided so that each of the divided light beam bundles illuminates the entire three liquid crystal panels 140R, 140G, 140B to be illuminated, and therefore each of them. The entire surface of the incident side of the liquid crystal panel has almost uniform illuminance.

The polarization conversion element 114 is composed of a polarization beam splitter array and is arranged between the second lens array 113 and the superimposing lens 115. As a result, the random polarized light from the light source is converted into polarized light having a specific polarization direction in advance, the light amount loss in the incident side polarizer, which will be described later, is reduced, and the brightness of the screen is improved.

The light whose brightness is uniformized and polarized as described above is sequentially converted into a red channel, a green channel, and a blue channel by dichroic mirrors 121, 123, and 132 for separating into three primary colors of RGB via a reflection mirror 122. They are separated and incident on the liquid crystal panels 140R, 140G, and 140B, respectively.

The polarizing film 142 of the present invention is arranged on the incident side of the liquid crystal panels 140R, 140G, 140B, and the polarizing film 143 of the present invention is arranged on the emitting side of the liquid crystal panels 140R, 140G, and 140B.

The polarizing film 142 and the polarizing film 143 arranged in each of the RGB optical paths are arranged so that their respective absorption axes are orthogonal to each other. The liquid crystal panels 140R, 140G, and 140B arranged in each optical path have a function of converting a polarization state controlled for each pixel by an image signal into an amount of light.

The optical film of the present invention is useful as a polarizing film having excellent durability in any of the optical paths of blue channel, green channel, and red channel by selecting the type of dichroic dye suitable for the corresponding channel.

The optical image created by transmitting the incident light with different transmittances for each pixel according to the image data of the liquid crystal panels 140R, 140G, 140B is synthesized by the cross dichroic prism 150, and the screen 180 by the projection lens 170. Enlarged projection.

As electronic paper, those displayed by molecules such as optical anisotropy and dye molecular orientation, those displayed by particles such as electrophoresis, particle movement, particle rotation, and phase change, and one end of the film move. This includes those displayed by the color development / phase change of the molecule, those displayed by the light absorption of the molecule, and those displayed by self-luminous combination of electrons and holes. More specifically, microcapsule type electrophoresis, horizontally moving type electrophoresis, vertically moving type electrophoresis, spherical twist ball, magnetic twist ball, cylindrical twist ball method, charged toner, electron powder fluid, magnetic electrophoresis type, magnetic heat sensitivity. Formula, electrowetting, light scattering (transparent / white turbidity change), cholesteric liquid crystal / photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, bicolor dye / liquid crystal dispersion type, movable film, leuco dye Examples thereof include bleaching and erasing by, photochromic, electrochromic, electrodeposition, and flexible organic EL. The electronic paper may be used not only for personal use of texts and images, but also for display of advertisements (signage) and the like. According to the optical film of the present invention, the thickness of the electronic paper can be reduced.

As a stereoscopic display device, for example, a method of arranging different retardation films alternately such as a micropole method has been proposed (Japanese Patent Laid-Open No. 2002-185983), but when the optical film of the present invention is used as a polarizing film, Since patterning is easy by printing, inkjet, photolithography, etc., the manufacturing process of the display device can be shortened, and a retardation film is not required.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "part" in the example are mass% and parts by mass.

In the examples, the following polymerizable liquid crystal compounds were used.
Compound (1-6) (Compound represented by the following formula (1-6))
Compound (1-6) is described in Lubet al. Recl. Trav. Chim. It was synthesized by the method described in Pays-Bas, 115, 321-328 (1996).

[Measurement of phase transition temperature]
The phase transition temperature was confirmed by observing the texture with a polarizing microscope (BX-51, manufactured by Olympus Corporation) while heating the compound on the glass substrate on which the alignment film was formed. The compound represented by the formula (1-6) exhibits a smectic A phase from a crystalline phase at 95 ° C., undergoes a phase transition to a nematic phase at 111 ° C., and changes to an isotropic liquid phase at 113 ° C. at the time of temperature rise. Transferred. It was confirmed that during the temperature decrease, the phase transitioned to the nematic phase at 112 ° C., the phase transition to the smectic A phase at 110 ° C., and the phase transition to the smectic B phase at 94 ° C.

Compound (1-7) (Compound represented by the following formula (1-7))
Compound (1-7) is described in Lubet al. Recl. Trav. Chim. It was synthesized by the method described in Pays-Bas, 115, 321-328 (1996).

[Measurement of phase transition temperature]
The phase transition temperature was confirmed by observing the texture with a polarizing microscope. The compound represented by the formula (1-7) undergoes a smectic A phase from a crystalline phase at 81 ° C., a nematic phase transition at 121 ° C., and a phase transition to an isotropic liquid phase at 137 ° C. at the time of temperature rise. bottom. It was confirmed that at the time of temperature decrease, the phase transitioned to the nematic phase at 133 ° C., the phase transition to the smectic A phase at 118 ° C., and the phase transition to the smectic B phase at 78 ° C.

Example 1
[Preparation of polymerizable liquid crystal composition]
The following components were mixed and stirred at 80 ° C. for 1 hour to obtain a polymerizable liquid crystal composition.
Polymerizable liquid crystal compound; Compound (1-6) 100 parts Bicolor dye; Azo dye (NKX2029; manufactured by Hayashihara Biochemical Research Institute) Part 2 Polymerization initiator; 2-Dimethylamino-2-benzyl-1- (4-) Morphorinophenyl) Butan-1-one (Irgacure 369; manufactured by BASF Japan) 6 parts Polymerization initiator; Isopropylthioxanthone (manufactured by Sebel Hegner Japan) 2 parts Leveling agent; Polyacrylate compound (BYK-361N; BYK-Chemie) (Manufactured) 1.2 parts Solvent; 250 parts of cyclopentanone

[Manufacturing of optical film]
A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied onto a glass substrate by a spin coating method, and after drying, an alignment film having a thickness of 89 nm was formed. Subsequently, the surface of the obtained alignment film was subjected to a rubbing treatment. The rubbing process uses a semi-automatic rubbing device (trade name: LQ-008 type, manufactured by Joyo Engineering Co., Ltd.) and a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Kako Co., Ltd.) with a pushing amount of 0.15 mm. The operation was carried out under the conditions of a rotation speed of 500 rpm and 16.7 mm / s.
The polymerizable liquid crystal composition is applied onto the alignment film after rubbing by a spin coating method, heated and dried on a hot plate at 120 ° C. for 3 minutes, and then quickly cooled to 70 ° C. (a temperature showing a smectic phase when the temperature is lowered). After drying, a coating film was obtained. It was produced on a glass substrate by irradiating the coating film with ultraviolet rays having ^{an exposure amount of 2400 mJ / cm 2} (365 nm standard) using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio, Inc.). An optical film was obtained.

[Measurement of two-color ratio]
^{Double beam for the absorbance (A 1} ) in the transmission axis direction and the absorbance ^{(A 2} ) in the absorption axis direction at the maximum absorption wavelength using a device in which a folder with a polarizer is set in an ultraviolet visible spectrophotometer UV-3150 manufactured by Shimadzu Corporation. Measured by method. The folder was provided with a mesh that cuts the amount of light by 50% on the reference side. The ratio (A 2 / A ¹ ) was calculated from the ^{measured absorbance (A 1} ) in the transmission axis direction and the absorbance ^{(A 2} ) in the absorption axis direction, and used as the ^{two-color ratio.} The results are shown in Table 2. It can be said that the higher the two-color ratio, the more useful it is as a polarizing film.

[Film thickness measurement]
The film thickness of the obtained optical film was measured using a laser microscope (LEXT3000, manufactured by Olympus Corporation). The results are shown in Table 2.

[Measurement of haze]
The haze value of the obtained optical film was measured using a haze meter (HZ-2; manufactured by Suga Test Instruments Co., Ltd.). The results are shown in Table 2.

[Observation of liquid crystal phase]
The liquid crystal phase shown by the obtained optical film was observed using a polarizing microscope (BX-51, manufactured by Olympus Corporation). The observation was carried out by arranging the retarding axis of the obtained polarizing film between the two polarizing elements whose transmission axes are orthogonal to each other so that the slow axis of the obtained polarizing film is in the direction of 45 ° with respect to the transmission axis.
When it was found that a horizontally oriented monodomain was formed, it was marked with a circle in Table 2. The results are shown in Table 2.

[Observation of unevenness]
The obtained optical film was arranged so that the absorption axis was orthogonal to the iodine-PVA polarizing plate (SRW842A; manufactured by Sumitomo Chemical Co., Ltd.), and was visually observed on a direct backlight. When phase-separated unevenness was not observed, it was marked with a circle in Table 2. The results are shown in Table 2.

Examples 2 to 15, Reference Examples 1 and 2
A polymerizable liquid crystal composition was obtained in the same manner as in Example 1 except that the types of the polymerizable liquid crystal compounds and the types and amounts of the leveling agents were changed as shown in Table 1.

The following leveling agents were used as shown in Table 1.
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)
Polyacrylate compound (BYK-352; manufactured by BYK-Chemie)
Polyacrylate compound (BYK-354; manufactured by BYK-Chemie)
Polyacrylate compound (BYK-381; manufactured by BYK-Chemie)
Polyacrylate compound (BYK-392; manufactured by BYK-Chemie)
Fluorine-containing oligomer (Mega Fvck F471; manufactured by DIC Corporation)
Fluorine-containing oligomer (Mega Fvck F477; manufactured by DIC Corporation)

The polymerizable liquid crystal compositions of Examples 2 to 15 and Reference Examples 1 and 2 obtained above were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 16
[Preparation of polymerizable liquid crystal composition]
The following components were mixed and stirred at 80 ° C. for 1 hour to obtain a polymerizable liquid crystal composition.
Polymerizable liquid crystal compound; 100 parts of compound (1-6) Polymerization initiator; 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (Irgacure 369; manufactured by BASF Japan) 6 parts Polymerization initiator; 2-isopropylthioxanthone (manufactured by Sebel Hegner, Japan) 2 parts Leveling agent; polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts Solvent: 250 parts of cyclopentanone

[Manufacturing of optical film]
An optical film was obtained in the same manner as in Example 1.

[Observation of liquid crystal phase]
When the liquid crystal phase of the obtained optical film was observed in the same manner as in Example 1, it was confirmed that a horizontally oriented monodomain was formed.

[Measurement of film thickness]
The film thickness of the obtained optical film was measured in the same manner as in Example 1 and found to be 1.8 μm.

[Measurement of phase difference value]
The front retardation value of the obtained optical film at a wavelength of 587.7 nm was measured using a birefringence measuring device (KOBRA-WR, manufactured by Oji Measuring Instruments Co., Ltd.) and found to be 257 nm. Since the glass substrate used as the base material does not have birefringence, the front phase difference value of the optical film produced on the glass substrate can be obtained by measuring the film with the glass substrate with a measuring machine. ..

According to the polymerizable liquid crystal composition of the present invention, an optical film having a horizontally oriented smectic phase formed can be easily obtained, and the two-color ratio is high.

10 Liquid crystal display 11 Antireflection film 12a, 12b Polarizing film 13a, 13b Phase difference film 14a, 14b Substrate 15 Color filter 16 Transparent electrode 17 Liquid crystal layer 18 Interlayer insulating film 19 Backlight unit 20 Black matrix 21 Thin film transistor 22 Pixel electrode 23 Spacer 24 Liquid crystal display 30 EL display 31 Polarizing film 32 Phase difference film 33 Substrate 34 Interlayer insulation film 35 Pixel electrode 36 Light emitting layer 37 Cathode electrode 38 Drying agent 39 Sealing lid 40 Thin film transistor 41 Rib 42 Thin film sealing film 44 EL display device 111 Light source 112 First lens array 112a Lens 113 Second lens array 114 Polarization conversion element 115 Superimposition lens 121,123,132 Dichroic mirror 122 Reflection mirror 140R, 140G, 140B Liquid crystal panel 142,143 Polarizing film 150 Cross dichroic prism 170 Projection lens 180 screen

Claims (2)

A method for producing an optical film, which comprises the steps (1) to (3).
Step (1): Contains a polymerizable liquid crystal compound exhibiting a smectic phase, a leveling agent, a dichroic dye and a solvent.
The leveling agent is at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component.
The content of the leveling agent is 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound.
The dichroic dye is of formula (2-B):
(-N = N-A ² ) p-N = N- (2-B)
[In formula (2-B), A ² represents a p-phenylene group which may independently have a substituent. p represents an integer of 1 to 4. When p is an integer of 2 or more, the plurality of A ^2s may be the same or different from each other. The is a compound having a structure represented by <br/> polymerizable liquid crystal composition is coated on a substrate, the polymerizable liquid crystal compound than the temperature exhibiting a nematic phase, the polymerizable liquid crystal compound showing a nematic phase By heating at a temperature 100 degrees higher than the temperature or lower, the solvent is dried to obtain a coating film showing a nematic phase. Step (2): A smectic phase is formed on the coating film obtained in step (1). Step of converting to a film (3): A step of polymerizing a polymerizable liquid crystal compound contained in the film formed by the smectic phase to obtain an optical film. Wherein step (2) is the by polymerizable liquid crystal compound is cooled the coating film to a temperature showing a smectic phase, the production method according to claim 1, wherein the step of converting the film smectic phase is formed.

Images