JP2006221116A - Coating film for optical compensation, coating liquid for forming coating film, optical element manufactured by using the coating liquid, and method of manufacturing optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating film for optical compensation which has a characteristic of [(n<SB>x</SB>+n<SB>y</SB>)/2-n<SB>z</SB>]×d<0 without the need for a complicated film forming process, and also to provide an optical element which has the characteristic without the labor and time for sticking a film or the like. <P>SOLUTION: The coating film for optical compensation contains a polymer satisfying a relation:[(n<SB>x</SB>+n<SB>y</SB>)/2-n<SB>z</SB>]×d<0 , wherein (n<SB>x</SB>) denotes a maximum value among refractive indexes within a thin film-formed plane, (n<SB>y</SB>) denotes a minimum value among them, (n<SB>z</SB>) denotes a refractive index in a thickness direction, and (d) denotes film thickness. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention uses an optical compensation coating film for optical compensation of retardation by a liquid crystal cell, an optical compensation coating film forming coating solution suitable for forming the coating film, and the coating liquid. The present invention relates to an optical element manufactured by the method and a method for manufacturing the optical element.

In a liquid crystal display device, a phase difference film for optical compensation is used in order to compensate for a phase difference due to birefringence of a liquid crystal cell and to expand a viewing angle. For example, a polymer such as polycarbonate, polyester, polystyrene, polyamide, polyimide, polyethersulfone, solution casting method, uniaxial stretching method of a dried product after solution casting, biaxial stretching method of a dried product after solution casting, extrusion method, Examples thereof include those formed into a film by a uniaxial stretching method of an extruded product, a biaxial stretching method of an extruded product, a calendar method, and the like (for example, see Patent Document 1 and Patent Document 2). Depending on the liquid crystal used, a film made of a material having a positive intrinsic birefringence value such as polycarbonate and a film made of a material having a negative intrinsic birefringence value such as polystyrene are properly used. In order to use the film, a complicated film forming process is required, and it takes time and effort to affix it to liquid crystal display device components. To solve this problem, paste coating of polyimide has been proposed which has the optical properties of _{n z <n x = n y} ( e.g., see Patent Document 3.). However, those having an optical characteristics of the _{n z> n x ≧ n y} , in other words, _{[(n x + n y) /} 2-n z ] that the value of the thickness retardation expressed as × d is negative Has not been proposed.
JP-A-3-33719 JP 11-248939 A JP 2001-290023 A

An object of the present invention is to provide an optical compensation coating film having a characteristic of [(n _x + _ny ) / 2− _nz ] × d <0 without requiring a complicated film forming step, and film pasting It is an object of the present invention to provide an optical element having the characteristics without requiring such troubles.

Such problems present inventors to solve is the result of intense research, largest of the n _x of the in-plane refractive index of the time of thinning, the smallest ones and n _y, in the thickness direction refraction An optical compensation coating film comprising a polymer satisfying a relationship of [(n _x + _ny ) / 2− _nz ] × d <0, where the rate is n _z and the film thickness is d As a result, the inventors have found that the above-described problems can be solved, and have reached the present invention.

That is, the present invention
When largest of the n _x of the in-plane refractive index of the time of thinning, the smallest ones and n _y, the refractive index in the thickness direction n _z, the film thickness is d, [(n _x + n _y ) / 2- _nz ] × d <0, a coating film for optical compensation characterized in that it contains a polymer satisfying the relationship:
The optical compensation coating film (claim 2) according to claim 1, wherein the polymer is an aromatic vinyl polymer.
The polymer contains or is at least one selected from poly (1-vinylnaphthalene), poly (2-vinylnaphthalene), and poly (4-vinylbiphenyl). Or a coating film for optical compensation according to claim 2 (claims 3 and 4),
It is a coating liquid for forming an optical compensation coating film formed by containing the following (A) and (B) (claim 5),
(A) The polymer according to claims 1 to 4 (B) The solvent in which the component (A) is soluble After the coating liquid for forming an optical compensation coating film according to claim 5 is applied to a substrate, It is a method for producing an optical element (Claims 6 and 7), wherein the coating film is annealed by exposure to the vapor of the component (B) as necessary and dried.
An optical element (Claim 8) obtained by applying the coating liquid for forming an optical compensation coating film according to claim 5 to a substrate and drying the substrate.
It is an optical element (Claim 9) manufactured by the manufacturing method of any one of Claim 6 or Claim 7.

The maximum one of n _x of the in-plane refractive index, minimum one of the n _y, the refractive index in the thickness direction n _z, the thickness is taken as d, _{[(n x + n y) /} 2 An optical compensation coating film characterized by satisfying the relationship of −n _z ] × d <0 was provided.

Further, an unstretched film formed by the solution casting method when the maximum refractive index in the plane is _nx , the minimum is _ny , the refractive index in the thickness direction is _nz , and the film thickness is d. The coating film for optical compensation formed using the polymer which satisfy | fills the relationship of [( _nx + _ny ) / 2- _nz ] * d <0 was provided.

Further, an unstretched film formed by the solution casting method when the maximum refractive index in the plane is _nx , the minimum is _ny , the refractive index in the thickness direction is _nz , and the film thickness is d. Provides a coating solution for forming an optical compensation coating film comprising a polymer satisfying the relationship of [(n _x + _ny ) / 2− _nz ] × d <0 and a solvent capable of solubilizing the polymer. did.

Further, an unstretched film formed by the solution casting method when the maximum refractive index in the plane is _nx , the minimum is _ny , the refractive index in the thickness direction is _nz , and the film thickness is d. A coating solution for forming an optical compensation coating film comprising a polymer satisfying the relationship of [(n _x + _ny ) / 2− _nz ] × d <0 and a solvent capable of solubilizing the polymer. An optical element manufacturing method is provided in which the polymer is annealed by being exposed to a vapor of a solvent capable of being dissolved as necessary and further dried.

When the optical compensation coating film of the present invention is used, an optical compensation of [(n _x + _ny ) / 2− _nz ] × d <0 is achieved without the need for complicated film forming steps and film sticking. Since an optical element having a layer can be produced, it is extremely useful industrially.

  Hereinafter, the present invention will be described in detail.

In the present invention, when the largest of the n _x of the in-plane refractive index of the time of thinning, the smallest ones and n _y, the refractive index in the thickness direction n _z, the film thickness is d, [( _{n x + n y) / 2} -n z ] × d <polymer satisfies the relationship of 0, or, in the unstretched film was formed into a film by a solution casting method _{[(n x + n y) /} 2-n z ] × d As the polymer satisfying the relationship <0 (hereinafter sometimes referred to as the component (A)), an aromatic vinyl polymer can be suitably used from the viewpoint that the above formula can be satisfied.

The component (A) is a polymer that satisfies a relationship of [(n _x + _ny ) / 2− _nz ] × d <0. For example, polystyrene; poly (α-methylstyrene); poly (2-methylstyrene), poly (3-methylstyrene), poly (4-methylstyrene), poly (2,4-dimethylstyrene), poly (2, 5-dimethylstyrene), poly (3,4-dimethylstyrene), poly (3,5-dimethylstyrene), poly (2-ethylstyrene), poly (3-ethylstyrene), poly (4-ethylstyrene), Poly (2,4-diethylstyrene), poly (2,5-diethylstyrene), poly (3,4-diethylstyrene), poly (3,5-diethylstyrene), poly (2-propylstyrene), poly ( 3-propyl styrene), poly (4-propyl styrene), poly (2,4-dipropyl styrene), poly (2,5-dipropyl styrene), poly (3,4- Propylstyrene), poly (3,5-dipropylstyrene), poly (2-butylstyrene), poly (3-butylstyrene), poly (4-butylstyrene), poly (2,4-dibutylstyrene), poly Poly (alkylstyrene) such as (2,5-dibutylstyrene), poly (3,4-dibutylstyrene), poly (3,5-dibutylstyrene); poly (2-methoxystyrene), poly (3-methoxystyrene) ), Poly (4-methoxystyrene), poly (2,4-dimethoxystyrene), poly (2,5-dimethoxystyrene), poly (3,4-dimethoxystyrene), poly (3,5-dimethoxystyrene), Poly (2-ethoxystyrene), poly (3-ethoxystyrene), poly (4-ethoxystyrene), poly (2,4-diethoxystyrene), poly Poly (2,5-diethoxystyrene), poly (3,4-diethoxystyrene), poly (3,5-diethoxystyrene), poly (2-propoxystyrene), poly (3-propoxystyrene), poly (4-propoxystyrene), poly (2,4-dipropoxystyrene), poly (2,5-dipropoxystyrene), poly (3,4-dipropoxystyrene), poly (3,5-dipropoxystyrene) , Poly (2-butoxystyrene), poly (3-butoxystyrene), poly (4-butoxystyrene), poly (2,4-dibutoxystyrene), poly (2,5-dibutoxystyrene), poly (3 , 4-dibutoxystyrene), poly (3,5-dibutoxystyrene) and the like; poly (alkoxystyrene); poly (2-chlorostyrene), poly (3-chlorostyrene) ), Poly (4-chlorostyrene), poly (2,4-dichlorostyrene), poly (2,5-dichlorostyrene), poly (2,6-dichlorostyrene), poly (3,4-dichlorostyrene) , Poly (2-bromostyrene), poly (3-bromostyrene), poly (4-bromostyrene), poly (2,4-dibromostyrene), poly (2,5-dibromostyrene), poly (2,6 -Dibromostyrene), poly (3,4-dibromostyrene), poly (2-iodostyrene), poly (3-iodostyrene), poly (4-iodostyrene), poly (2,4-diiodostyrene), Poly (2,5-diiodostyrene), poly (2,6-diiodostyrene), poly (3,4-diiodostyrene), poly (2-fluorostyrene), poly (3-fluorostyrene) ), Poly (4-fluorostyrene), poly (2,4-difluorostyrene), poly (2,5-difluorostyrene), poly (2,6-difluorostyrene), poly (3,4-difluorostyrene), etc. Poly (halogenated styrene); poly (2-methoxycarbonylstyrene), poly (4-methoxycarbonylstyrene), poly (2-ethoxycarbonylstyrene), poly (4-ethoxycarbonylstyrene), poly (2-propoxycarbonyl) Styrene), poly (4-propoxycarbonylstyrene), poly (2-butoxycarbonylstyrene), poly (4-butoxycarbonylstyrene) and the like poly (vinyl benzoate); poly (o-hydroxystyrene), poly (m -Hydroxystyrene), poly (p-hydroxystyrene), etc. Poly (hydroxystyrene); vinyl naphthalene polymers such as poly (1-vinylnaphthalene) and poly (2-vinylnaphthalene); poly (4-vinylbiphenyl), poly (3- (4-biphenyl) styrene), poly Poly (arylstyrene) such as (4- (4-biphenyl) styrene); polyacenaphthylene and the like can be mentioned. Moreover, these 2 or more types of copolymers; The copolymer of these 1 type, or 2 or more types and another polymer can also be used. For example, styrene- (α-methylstyrene) copolymer, styrene- (2-methylstyrene) copolymer, styrene- (3-methylstyrene) copolymer, styrene- (4-methylstyrene) copolymer, Styrene- (2-methoxystyrene) copolymer, styrene- (3-methoxystyrene) copolymer, styrene- (4-methoxystyrene) copolymer, styrene- (2-chlorostyrene) copolymer, styrene- (3-chlorostyrene) copolymer, styrene- (4-chlorostyrene) copolymer, styrene- (2-methoxycarbonylstyrene) copolymer, styrene- (4-methoxycarbonylstyrene) copolymer, styrene- (O-hydroxystyrene) copolymer, styrene- (m-hydroxystyrene) copolymer, styrene- (p-hydroxystyrene) ) Copolymer, styrene- (1-vinylnaphthalene) copolymer, styrene- (2-vinylnaphthalene) copolymer, styrene- (4-vinylbiphenyl) copolymer, styrene-methyl acrylate copolymer, Styrenes such as styrene-methyl methacrylate copolymer, styrene-isoprene copolymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene-vinyl acetate copolymer Binary copolymer; (α-methylstyrene)-(2-methylstyrene) copolymer, (α-methylstyrene)-(3-methylstyrene) copolymer, (α-methylstyrene)-(4- Methylstyrene) copolymer, (α-methylstyrene)-(2-methoxystyrene) copolymer, (α-methylstyrene)-(3-methoxy Tylene) copolymer, (α-methylstyrene)-(4-methoxystyrene) copolymer, (α-methylstyrene)-(2-chlorostyrene) copolymer, (α-methylstyrene)-(3- (Chlorostyrene) copolymer, (α-methylstyrene)-(4-chlorostyrene) copolymer, (α-methylstyrene)-(2-methoxycarbonylstyrene) copolymer, (α-methylstyrene)-( 4-methoxycarbonylstyrene) copolymer, (α-methylstyrene)-(o-hydroxystyrene) copolymer, (α-methylstyrene)-(m-hydroxystyrene) copolymer, (α-methylstyrene) -(P-hydroxystyrene) copolymer, (α-methylstyrene)-(1-vinylnaphthalene) copolymer, (α-methylstyrene)-(2-vinylnaphthalene) copolymer , (Α-methylstyrene)-(4-vinylbiphenyl) copolymer, (α-methylstyrene) -methyl acrylate copolymer, (α-methylstyrene) -methyl methacrylate copolymer, (α-methyl (Styrene) -isoprene copolymer, (α-methylstyrene) -butadiene copolymer, (α-methylstyrene) -acrylonitrile copolymer, (α-methylstyrene) -maleic anhydride copolymer, (α-methyl) Α-methylstyrene binary copolymers such as styrene) -vinyl acetate copolymer; styrene-methyl acrylate-methyl methacrylate copolymer, styrene- (α-methylstyrene) -acrylonitrile copolymer, styrene- And terpolymers such as (α-methylstyrene) -methyl methacrylate copolymer. These polymers may be used alone or in combination of two or more.

  The polymer can be produced by polymerizing a single monomer or two or more monomers in the presence of a radical polymerization initiator, an anionic polymerization initiator, or a cationic polymerization initiator.

  The component (A) contains at least one selected from poly (1-vinylnaphthalene), poly (2-vinylnaphthalene), and poly (4-vinylbiphenyl). It is preferable in terms of heat resistance and availability.

  Further, the lower limit of the weight average molecular weight of the component (A) is preferably 10,000, more preferably 20000, still more preferably 30000, and the upper limit is preferably 1000000, more preferably 800000, and further preferably 600000. If the weight average molecular weight is less than 10,000, the coating film strength tends to decrease, and if the weight average molecular weight is greater than 1,000,000, it tends to be difficult to dissolve in the solvent. The weight average molecular weight is a value measured by gel permeation chromatography (GPC). In the present invention, two or more polymers having different weight average molecular weights may be used in combination, or may be used alone.

  Hereinafter, a coating solution for forming an optical compensation coating film (hereinafter sometimes simply referred to as a coating solution) will be described. The coating solution is preferably formed containing (A) the polymer and (B) a solvent in which the component (A) is soluble.

  The solvent for the component (B) is not particularly limited as long as the component (A) is soluble. Specific examples include benzene, toluene, o-xylene, m-xylene, and p-xylene. Hydrocarbon solvents such as isomer mixtures of ethylbenzene, isopropylbenzene and diethylbenzene; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, furfuryl alcohol, Alcohol solvents such as benzyl alcohol; ether solvents such as ethyl ether, isopropyl ether, 1,3-dioxolane, 1,4-dioxane, tetrahydropyran, tetrahydrofuran; acetone, 2-butanone, 4-methyl-2-pentanone, Ketone solvents such as cyclohexanone; methylene chloride , Chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane , Pentachloroethane, hexachloroethane, 1-chloropropane, 2-chloropropane, 1,1-dichloropropane, 1,2-dichloropropane, 1,3-dichloropropane, 2,2-dichloropropane, 1,2,3-tri Chloropropane, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-tri Halogen solvents such as chlorobenzene; methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, acetic acid Examples include ester solvents such as butyl; amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, and 1-methyl-2-pyrrolidinone. These solvents may be used alone or in combination of two or more.

  In the present invention, the amount of the solvent is preferably such that the ratio of the component (A) to the total weight of the components (A) and (B) is 1% by weight lower limit and 70% by weight upper limit, More preferably, the upper limit is 60% by weight, and the lower limit is 3% by weight and the upper limit is 50% by weight. When the proportion of the component (A) is less than 1% by weight, the coating film thickness tends to be thin and the required film thickness tends to be difficult to obtain, and when it is greater than 70% by weight, the viscosity of the coating liquid increases. , Workability tends to be inferior.

  Next, resins that can be added for the purpose of modifying the properties of the coating film of the present invention will be described. The resin that can be added includes polycarbonate resin, acrylic resin, polyester resin, polyolefin resin, polyamide resin, polyimide resin, polyvinyl alcohol resin, polyvinyl acetal resin, cellulose resin, polyethersulfone resin, polyarylate resin, epoxy. Resins, silicone resins, phenol resins, urethane resins and the like are exemplified, but these can be added within a range that does not impair the object and effect of the present invention.

  Next, additives that can be added for the purpose of modifying the properties of the coating film and coating solution of the present invention will be described.

  Additives include antioxidants (eg, hindered phenols such as IRGANOX 1010, IRGANOX 1135, IRGANOX 1330, etc. manufactured by Ciba Specialty Chemicals), processing stabilizers (eg, HP-136, IRGANOX manufactured by Ciba Specialty Chemicals). E201, IRGAFOS 168, etc.), light stabilizers (eg, hindered amines such as Sanol LS-765 and Sanol LS-770 manufactured by Sankyo Lifetech), ultraviolet absorbers (eg, TINUVIN P, TINUVIN 213 manufactured by Ciba Specialty Chemicals) Benzotriazoles such as TINUVIN 326), adhesion improvers (eg, silane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane) Pulling agent), silanol condensation catalyst (eg, aluminum tris (ethyl acetoacetate) manufactured by Kawaken Fine Chemicals, aluminum chelate M, etc.), plasticizer (eg, esters such as di-2-ethylhexyl phthalate, diisobutyl adipate) And surfactants (for example, fluorine compounds such as Fluorad FC-430 and Fluorad FC-4430 manufactured by Sumitomo 3M), antistatic agents (for example, IRGASTAT P18 and IRGASTAT P22 manufactured by Ciba Specialty Chemicals), and the like. These can be added as long as the objects and effects of the present invention are not impaired.

  The coating liquid of the present invention can be obtained, for example, by mixing the above-mentioned components at a temperature not lower than the melting point of the solvent and not higher than the boiling point, after standing, stirring and mixing.

  Next, the substrate for the optical element will be described. Various substrates can be used as the substrate, but it is preferable that the substrate is transparent particularly from the viewpoint of use. Specific examples include polycarbonate polymers produced by polycondensation from bisphenol A and carbonyl chloride; polyacrylic acid esters such as polymethyl acrylate and polymethyl methacrylate; adipic acid, phthalic acid, isophthalic acid, Polyester polymers obtained by condensation of dibasic acids such as terephthalic acid and glycols such as ethylene glycol, diethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, or ring-opening polymerization of lactones; polystyrene, poly (α- Styrene polymers such as methylstyrene); copolymers of acrylic acid ester and styrene; polyolefin polymers such as polyethylene, polynorbornene, hydrogenated polyisoprene, and hydrogenated polybutadiene; triacetyl cellulose Cellulose-based resins: polyamides such as nylon 6 and nylon 66; polyimides; polyamide-imides; polyvinyl alcohol; vinyl chloride; polyethersulfone; epoxy resins: silicone resins: compounds described in WO 01/37007 Polymer casting method, solution casting uniaxial stretching method, solution casting dried product biaxial stretching method, extrusion method, extruded product uniaxial stretching method, extruded product biaxial stretching method, calendar method And the like, films obtained by attaching these films to polarizing plates, glass plates, color filters, liquid crystal cells, and the like.

  Next, a method for manufacturing an optical element will be described.

  The optical element can be suitably manufactured by applying the coating liquid of the present invention to one side or both sides of the substrate, drying, or annealing and drying after coating. As coating methods, gravure roll coating method, Mayer bar coating method, doctor blade coating method, reverse roll coating method, dip coating method, air knife coating method, calendar coating method, skies coating method, kiss coating method, bar coating method , Slot die coating method, spin coating method and the like.

  As a drying method, it can be performed, for example, by leaving in air or in an inert gas such as nitrogen (air drying), heat drying in a hot air oven, an infrared heating furnace, or the like, drying under reduced pressure in a vacuum dryer, or the like. Although various drying temperatures can be set, a temperature range of a lower limit of −30 ° C. and an upper limit of 300 ° C. is preferable, a lower limit of 0 ° C. and an upper limit of 280 ° C. are more preferable, and a lower limit of 10 ° C. and an upper limit of 260 ° C. are more preferable. When the drying temperature is lower than −30 ° C., the drying time tends to be longer, and when it is higher than 300 ° C., the coating film and the substrate tend to be thermally deteriorated.

  Annealing is preferably performed for improving the leveling property of the coating film, stress relaxation, and the like, and is effective for, for example, reducing in-plane retardation and reducing in-plane retardation fluctuation. In the present invention, the annealing is preferably performed in the vapor of the component (B) with the coating film of the coating substrate facing up and left still horizontally. The temperature at the time of annealing can be variously set, but the lower limit is preferably −30 ° C. and the upper limit [(B) component boiling point (° C.)], and the lower limit is −15 ° C. and the upper limit [(B) component boiling point (° C.) −5 ° C.] is more preferable, and the lower limit is 0 ° C., and the upper limit [(B) component boiling point (° C.) − 10 ° C.] is more preferable. If the annealing temperature is lower than −30 ° C., the annealing time tends to be longer, and if the annealing temperature is higher than the boiling point (° C.) of the component (B), the coating film tends to flow out from the substrate. There is. The pressure at the time of annealing can also be set variously, and it can carry out under atmospheric pressure, pressurization, or pressure reduction, but atmospheric pressure is preferred at the point of workability.

  Next, the optical characteristics of the optical compensation coating film in the present invention will be described.

The coating film for optical compensation of the present invention preferably has a characteristic of [(n _x + _ny ) / 2− _nz ] × d <0. When the thickness of the optical compensation for coated film is d, the in-plane retardation is represented by _{(n x -n y) × d} , the thickness retardation, _{[(n x + n y) /} 2-n z ] Although represented by xd, the lower limit of the in-plane retardation is preferably 0 nm and the upper limit is 100 nm, more preferably the lower limit is 0 nm and the upper limit is 80 nm, and further preferably the lower limit is 0 nm and the upper limit is 60 nm. If the in-plane retardation is larger than 100 nm, it tends to be difficult to compensate for the retardation due to the birefringence of the liquid crystal cell. The thickness retardation is preferably lower limit −1000 nm and upper limit −1 nm, more preferably lower limit −800 nm and upper limit −10 nm, further preferably lower limit −600 nm and upper limit −20 nm. When the thickness phase difference is smaller than −1000 nm, it tends to be difficult to compensate for the phase difference due to the birefringence of the liquid crystal cell.

  Further, the optical compensation coating film of the present invention, the coating film forming coating liquid and the optical element produced using the coating liquid are used in video, camera, mobile phone, personal computer, TV, monitor, automobile, etc. It can be used suitably for liquid crystal display device manufacturing parts such as instrument panels.

  Examples are shown below to describe the present invention in more detail, but the present invention is not limited to these examples.

Example 1
To 12.0 g of poly (2-vinylnaphthalene) (Aldrich, weight average molecular weight: 175000), 88.0 g of methylene chloride was added and dissolved at 25 ° C. Next, this coating solution was applied to a 150 μm-thick glass substrate (average refractive index: 1.52, in-plane retardation: 0 nm, thickness retardation: 1 nm) using a bar coater, and then 6 ° C. at 25 ° C. The optical element was produced by air-drying in air for a period of time. The coating thickness after drying (d (nm)) was determined by measuring the thickness of the entire optical element and subtracting the thickness of the glass substrate. Next, the physical properties of the optical element obtained as described above were measured by the following method, and the results are shown in Table 1. Here, an optical element of [(n _x + _ny ) / 2− _nz ] × d <0 was obtained.

(1) Refractive index _{(n x, n y, n} z) using the measured Oji Scientific Instruments Ltd. automatic birefringence meter KOBRA-21ADH of, the refractive index was measured at 590nm light under 25 ° C.. From the results obtained, it was determined plane retardation by _{(n x -n y) × d} . In addition, the thickness retardation was determined by [( _nx + _ny ) / 2- _nz ] × d.

(Example 2)
95.0 g of methylene chloride was added to 5.0 g of poly (4-vinylbiphenyl) (manufactured by Aldrich, weight average molecular weight: 115000), and dissolved at 25 ° C. Next, this coating solution was applied to a 150 μm-thick glass substrate (average refractive index: 1.52, in-plane retardation: 0 nm, thickness retardation: 1 nm) using a bar coater, and then 6 ° C. at 25 ° C. The optical element was produced by air-drying in air for a period of time. The coating thickness after drying (d (nm)) was determined by measuring the thickness of the entire optical element and subtracting the thickness of the glass substrate. Next, the physical properties of the optical element obtained as described above were measured by the method described in Example 1, and the results are shown in Table 1. Here, an optical element of [(n _x + _ny ) / 2− _nz ] × d <0 was obtained.

(Example 3)
70.0 g of chloroform was added to 30.0 g of a styrene-maleic anhydride copolymer (Dylark D332 manufactured by Nova Chemical) and dissolved at 25 ° C. Next, this coating solution was applied to a 150 μm thick glass substrate (average refractive index: 1.52, in-plane retardation: 0 nm, thickness retardation: 1 nm) using a bar coater. The glass container was filled with chloroform vapor at atmospheric pressure, sealed, and then annealed at 25 ° C. for 48 hours. Thereafter, the coated substrate was taken out and air-dried at 25 ° C. for 6 hours to produce an optical element. The coating thickness after drying (d (nm)) was determined by measuring the thickness of the entire optical element and subtracting the thickness of the glass substrate. Next, the physical properties of the optical element obtained as described above were measured by the method described in Example 1, and the results are shown in Table 1. Here, an optical element of [(n _x + _ny ) / 2− _nz ] × d <0 was obtained.

Claims (14)

When largest of the n _x of the in-plane refractive index of the time of thinning, the smallest ones and n _y, the refractive index in the thickness direction n _z, the film thickness is d, [(n _x + n _y ) / 2- _nz ] × d <0, a polymer satisfying the relationship: an optical compensation coating film.   2. The coating film for optical compensation according to claim 1, wherein the polymer is an aromatic vinyl polymer.   2. The polymer according to claim 1, wherein the polymer contains at least one selected from poly (1-vinylnaphthalene), poly (2-vinylnaphthalene), and poly (4-vinylbiphenyl). 3. The coating film for optical compensation according to any one of 2 above.   4. The polymer according to claim 1, wherein the polymer is at least one selected from poly (1-vinylnaphthalene), poly (2-vinylnaphthalene), and poly (4-vinylbiphenyl). Optical compensation coating film. A coating solution for forming an optical compensation coating film formed by containing the following (A) and (B).
(A) Polymer according to claims 1 to 4 (B) A solvent in which component (A) is soluble   A method for producing an optical element, wherein the optical compensation coating film-forming coating solution according to claim 5 is applied to a substrate and then dried.   A method for producing an optical element, comprising: coating an optical compensation coating film forming coating solution according to claim 5 on a substrate; annealing the coating film by exposing to the vapor of component (B); and further drying.   An optical element obtained by coating the substrate with the coating solution for forming an optical compensation coating film according to claim 5 and drying the substrate.   The optical element manufactured by the manufacturing method of any one of Claim 6 or Claim 7. Largest of the n _x of the in-plane refractive index, minimum one of the n _y, the refractive index in the thickness direction n _z, the thickness is taken as d, _{[(n x + n y) /} 2-n _z ] × d <0, an optical compensation coating film characterized by satisfying the relationship: Largest of the n _x of the in-plane refractive index, smallest to n _y, the refractive index n _z in the thickness direction, the thickness is taken as d, the unstretched film was formed into a film by a solution casting method [ An optical compensation coating film formed using a polymer satisfying the relationship of (n _x + _ny ) / 2− _nz ] × d <0. Largest of the n _x of the in-plane refractive index, smallest to n _y, the refractive index n _z in the thickness direction, the thickness is taken as d, the unstretched film was formed into a film by a solution casting method [ A coating solution for forming an optical compensation coating film comprising a polymer satisfying the relationship of ( _nx + _ny ) / 2- _nz ] × d <0 and a solvent capable of solubilizing the polymer. Largest of the n _x of the in-plane refractive index, smallest to n _y, the refractive index n _z in the thickness direction, the thickness is taken as d, the unstretched film was formed into a film by a solution casting method [ ( _Nx + _ny ) / 2- _nz ] × d <0 and a coating solution for forming an optical compensation coating film comprising a solvent capable of solubilizing the polymer. A method of manufacturing an optical element that is processed and dried.   14. The method of manufacturing an optical element according to claim 13, further comprising a step of annealing the polymer by exposing it to a vapor of a soluble solvent.