JP3957082B2 - Method for producing retardation plate and method for producing optical compensation polarizing plate - Google Patents

Description

The present invention relates to a method for producing a retardation plate and a method for producing an optical compensation polarizing plate .

In order to compensate for the phase difference due to birefringence in a VA-type or OCB-type liquid crystal cell and expand the viewing angle for good visual recognition, when the in-plane refractive index is nx, ny, and the refractive index in the thickness direction is nz It is known that a retardation plate having a property of nx ≧ ny> nz by controlling a three-dimensional refractive index in two directions and thickness directions in the plane is useful.

Conventionally, as the above-described retardation plate having the characteristics of nx ≧ ny> nz, a laminated retardation plate formed by laminating a pair of uniaxially stretched films made of a polymer so that the in-plane slow axis directions are orthogonal to each other, In addition, a single-layer retardation plate obtained by subjecting a polymer film to transverse stretching or biaxial stretching by a tenter has been known (Patent Documents 1 and 2).

However, the conventional laminated phase difference plate has a problem that the thickness is large and it becomes bulky when used in combination with a polarizing plate, and requires a bonding process for each sheet, resulting in poor production efficiency. On the other hand, when the range of retardation that can be applied is narrow with the latter single-layer retardation plate and the retardation value (Rz) in the thickness direction is significantly larger than the retardation value (Re) in the normal direction, the single-phase retardation plate is single. In order to obtain a desired retardation value, it is necessary to use a laminated retardation plate in which two or more layers are laminated, and there is a problem of increasing the thickness and the bulk as in the former case.
JP-A-3-33719 Japanese Patent Laid-Open No. 3-24502

The present invention includes a purpose of developing the optical member manufacturing method capable and excellent in thin properties when are valid phase difference characteristic in a viewing angle expansion compensation for high contrast definitive in the liquid crystal display, and in combination with the polarizing plate To do.

The present invention is a method for producing a retardation film comprising a polymer stretched film A and a polymer layer B,
(1) a step of preparing a support substrate made of a polymer;
(2) At least one of a solution and a melt of at least one polymer selected from the group consisting of polyetherketone, polyamide, polyester, polyimide, polyamideimide, and polyesterimide is spread on the support substrate and applied. Forming a layer;
and,
(3) By stretching or shrinking the supporting substrate and the coating layer together, the supporting substrate becomes the polymer stretched film A, the coating layer becomes the polymer layer B, and the polymer stretched film. A satisfies Re = 20 to 300 nm and Rz / Re = 1.0 to 8, the polymer layer B satisfies Re = 1 to 100 nm and Rz / Re = 5 to 100, and the thickness of the polymer layer B Forming both the layers so that the thickness is 1 to 20 μm,
The manufacturing method of the optical film containing is provided.

In each layer of the polymer-based stretched film A or the polymer layer B,
The Re is an in-plane retardation of each layer, the Rz is a thickness direction retardation of each layer, and each is represented by the following formula:
In the following formula, nx and ny are in-plane refractive indexes of the respective layers, nz is a refractive index in the thickness direction of the respective layers, and d is a thickness (nm) of the respective layers.

(Nx-ny) d = Re
(Nx-nz) d = Rz

Furthermore, the present invention is a method for producing an optical compensation polarizing plate having a retardation layer on one side of a polarizing plate,
(4) A step of producing a retardation plate by the method of producing a retardation plate of the present invention,
and,
(5) The step of laminating the retardation plate on one side of the polarizing plate via an adhesive layer or an adhesive layer, and using the retardation plate as a retardation layer of the optical compensation polarizing plate,
A manufacturing method is provided.

According to the present invention, by satisfying the aforementioned Re and Rz, are the valid phase difference characteristic for optical compensation, such as a viewing angle widening of high contrast definitive in the liquid crystal display, and a polymer-based stretched film A Tansobutsu In addition, the polymer layer B can be formed as a coating film, and can be excellent in thinness even in a combined form with a polarizing plate.

The retardation plate manufactured by the retardation plate manufacturing method of the present invention (hereinafter also referred to as “retarding plate of the present invention”) has an in- plane refractive index of nx, ny, and a thickness direction refractive index of nz. When the thickness is d, (nx−ny) d = Re, and (nx−nz) d = Rz, the retardation layer has Re = 20 to 300 nm and Rz / Re = 1.0 to 8 satisfactory polymeric stretched film a to, and Re = 1 to 100 nm and a thickness that satisfy the Rz / Re = 5 to 100, is made of both the polymer layer B composed of a coating film of 1 to 20 [mu] m. An optical compensation polarizing plate produced by the method for producing an optical compensation polarizing plate of the present invention (hereinafter also referred to as “optical compensation polarizing plate of the present invention” or “optical compensation polarizing plate of the present invention”) is provided on one side of the polarizing plate. An optical compensation polarizing plate having a retardation layer, wherein the retardation plate is an optical compensation polarizing plate comprising the retardation layer of the present invention.

There is no limitation in particular about the polymer which forms the polymer-type stretched film A, The suitable thing of a light transmittance can be used 1 type or in mixture of 2 or more types. In particular, a polymer capable of forming a film having excellent light transmittance of 75% or more, particularly 85% or more, and having excellent surface smoothness, uniformity of birefringence, and heat resistance is preferable. From the viewpoint of stable mass productivity of the stretched film exhibiting the retardation characteristics Re and Rz described above, a polymer exhibiting positive birefringence in which the refractive index in the stretching direction is high can be preferably used.

Incidentally, examples of the polymer exhibiting positive birefringence described above include norbornene polymers and polycarbonates, polyethersulfone and polysulfone, polyolefins and acrylic polymers, cellulose resins and polyarylate, polystyrene and polyvinyl alcohol, polyvinyl chloride, Examples thereof include polyvinylidene chloride and acetate polymers. In addition, the polymer which shows the negative birefringence in which the refractive index of the extending | stretching direction becomes low, such as the polymer which forms the polymer layer B mentioned later, can also be used.

The film to be stretched can be formed by applying an appropriate film forming method such as a casting film forming method, a casting method such as a roll coating method or a flow coating method, or an extrusion method. In particular, a film formed by a solution casting method such as a casting method can be preferably used from the viewpoint of mass productivity of a stretched film with little thickness unevenness and alignment strain unevenness. In forming the film, various additives including stabilizers, plasticizers, metals, and the like can be blended as necessary.

The polymer-based stretched film A that can be preferably used in view of the optical compensation effect and the like has an in-plane refractive index of nx, ny, a thickness direction refractive index of nz, a thickness of d, and (nx−ny) d = Re, And (nx−nz) d = Rz (hereinafter the same), Re = 250 nm or less, especially 22 to 200 nm, especially 25 to 150 nm, and Rz / Re = 7 or less, especially 6 or less, especially 5 or less. Satisfied.

Formation of the polymer-based stretched film A can be achieved, for example, by subjecting the polymer film to a roll treatment longitudinal stretching method, a tenter transverse stretching method, a biaxial stretching method, or the like, by subjecting the polymer film to a stretching treatment that exhibits the desired retardation characteristics. It can be carried out. In that case, the heating in the roll method longitudinal stretching method can be performed by any method of a method using a heating roll, a method of heating an atmosphere, or a method of using them together.

In the biaxial stretching method, any of a simultaneous biaxial stretching treatment method using an all tenter method and a sequential biaxial stretching treatment method using a roll tenter method can be employed. The stretching treatment temperature can be based on the conventional one, and is preferably in the vicinity of the glass transition temperature of the polymer forming the film, especially above the glass transition temperature.

The thickness of the polymer-based stretched film A can be appropriately determined according to the target retardation characteristics and the like. In general, it is 200 μm or less, especially 30 to 150 μm, particularly 40 to 120 μm for the purpose of thinning.

The polymer layer B is formed as a coating film formed by liquefying a solid polymer, developing the polymer, and solidifying the developing layer. Thereby, thickness can be 1-20 micrometers. In the above-described stretched film system, it is difficult to make the thickness 20 μm or less from the viewpoint of film strength, and it is difficult to give the desired retardation characteristics with the thickness. The thickness of the polymer layer B is preferably 15 μm or less, more preferably 12 μm or less, particularly 2 to 10 μm, from the viewpoint of thinning and imparting the desired retardation characteristics.

For the formation of the polymer layer B, an appropriate solid polymer capable of forming a layer satisfying Re = 1 to 100 nm and Rz / Re = 5 to 100 by a coating method can be used. A solid polymer with good heat resistance capable of forming a layer having excellent light transmissivity having a light transmittance of 75% or more, particularly 85% or more is preferred. Specifically, polyether ketone, especially polyaryl ether ketone, polyamide, polyester, polyimide, polyamide imide or polyester imide, or a mixture of two or more thereof is used from the viewpoint of the coating layer formability and the like. .

Incidentally, specific examples of the above-described polyether ketone, particularly polyaryl ether ketone, include those having a repeating unit represented by the following general formula (1) (Japanese Patent Laid-Open No. 2001-49110).

In the general formula (1), X is a halogen, an alkyl group, or an alkoxy group, and the number of X bonds to the benzene ring q, that is, the p-tetrafluorobenzoylene group and the oxyalkylene group are not bonded. The value of the number of substitutions q of hydrogen atoms is an integer of 0-4. R ¹ is a compound (group) represented by the following general formula (2), and m is 0 or 1. Further, n represents the degree of polymerization, and preferably 2 to 5000, and more preferably 5 to 500.

Examples of the halogen as X in the general formula (1) include a fluorine atom, a bromine atom, a chlorine atom and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group include linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, and butyl group. A halogenated alkyl group such as a medium methyl group, an ethyl group, or a trifluoromethyl group thereof is preferable.

Furthermore, examples of the alkoxy group include linear or branched alkoxy groups having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group. In particular, a halogenated alkoxy group such as a methoxy group, an ethoxy group, or a trifluoromethoxy group thereof is preferable. In the above, X is particularly preferably a fluorine atom.

On the other hand, in the group represented by the general formula (2), X ′ is a halogen, an alkyl group or an alkoxy group, and the value of the number of bonds q ′ of X ′ to the benzene ring is an integer of 0 to 4. . Examples of the halogen, alkyl group or alkoxy group as X ′ are the same as those described above for X.

Preferred X ′ is a fluorine atom, a methyl group or an ethyl group, a halogenated alkyl group such as trifluoromethyl group, a methoxy group or an ethoxy group, or a halogenated alkoxy group such as trifluoromethoxy group. A fluorine atom is preferred.

In the general formula (1), X and X ′ may be the same or different. Moreover, based on the fact that q or q ′ is 2 or more in general formulas (1) and (2), two or more X or X ′ present in the molecule may be the same or different from each other. It may be.

Particularly preferred R ¹ is a group represented by the following general formula (3).

In the general formulas (2) and (3), R ² is a divalent aromatic group, and P is 0 or 1. Examples of the divalent aromatic group include (o, m or p-) phenylene group, naphthalene group, biphenyl group, anthracene group, (o, m or p-) terphenyl group, phenanthrene group, dibenzofuran group, biphenyl. Examples thereof include an ether group, a biphenylsulfone group, and a divalent aromatic group represented by the following formula. In the divalent aromatic group, hydrogen directly bonded to the aromatic ring may be substituted with the halogen, alkyl group or alkoxy group described above.

In the above, preferable divalent aromatic groups (R ² ) are those represented by the following formulae.

The polyaryl ether ketone represented by the general formula (1) may be composed of the same repeating unit, or may have two or more different repeating units. In the latter case, each repeating unit may exist in a block form or may exist randomly.

Based on the above, preferable polyaryl ether ketones represented by the general formula (1) are those represented by the following general formula (4).

A preferable polyaryletherketone including a group at the molecular end is represented by the following general formula (5) corresponding to the general formula (1), and corresponds to the general formula (4). Is represented by the following general formula (6). In these, a fluorine atom is bonded to the p-tetrafluorobenzoylene group side in the molecule, and a hydrogen atom is bonded to the oxyalkylene group side.

On the other hand, specific examples of the polyamide or polyester described above include those having a repeating unit represented by the following general formula (7).

In the general formula (7), B is halogen, an alkyl group having 1 to 3 carbon atoms or a halide thereof, a phenyl group substituted with one or more of them, or an unsubstituted phenyl group. . z is an integer of 0-3.

E is a covalent bond, an alkenyl group having 2 carbon atoms or a halide thereof, CH ₂ group, C (CX ₃ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (R) ₂ group, or NR group. X in the C (CX ₃ ) ₂ group is a hydrogen atom or halogen, and R in the Si (R) ₂ group and the NR group is an alkyl group having 1 to 3 carbon atoms or a halide thereof. E is in a meta position or a para position with respect to the carbonyl group or the Y group. Halogen is a fluorine atom, a chlorine atom, an iodine atom or a bromine atom (hereinafter the same in general formula (7)).

Y is an O atom or an NH group. A is a hydrogen atom, halogen, an alkyl group having 1 to 3 carbon atoms or a halide thereof, a nitro group, a cyano group, a thioalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a halide thereof, aryl Group or a halide thereof, an alkyl ester group having 1 to 9 carbon atoms, an aryl ester group having 1 to 12 carbon atoms or a substituted derivative thereof, or an arylamide group having 1 to 12 carbon atoms or a substituted derivative thereof.

N is an integer of 0 to 4, p is an integer of 0 to 3, q is an integer of 1 to 3, and r is an integer of 0 to 3. A preferred polyamide or polyester has a repeating unit represented by the following general formula (8), wherein r and q are 1, and at least one of the biphenyl rings is substituted at the 2-position and the 2′-position. Is.

In the general formula (8), m is an integer of 0 to 3, preferably 1 or 2, and x and y are 0 or 1, and are not 0 at the same time. The other symbols have the same meaning as in the general formula (7), but E is a covalent bond in para orientation with respect to the carbonyl group or Y group.

In the general formulas (7) and (8), when a plurality of B, E, Y, or A are present in the molecule, they may be the same or different. Similarly, z, n, m, x, and y may be the same or different. In this case, B, E, Y, A, z, n, m, x, and y are determined independently.

The polyamide or polyester represented by the general formula (7) may be composed of the same repeating unit, or may have two or more different repeating units. In the latter case, each repeating unit may exist in a block form or may exist randomly.

On the other hand, specific examples of the polyimide described above include, for example, a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and an aromatic tetracarboxylic dianhydride, and are represented by the following general formula (9). And those having one or more repeating units.

In the general formula (9), R is a hydrogen atom, a halogen, a phenyl group, a phenyl group substituted with 1 to 4 halogens or an alkyl group having 1 to 10 carbon atoms, or 1 to 10 An alkyl group having a carbon atom. Four Rs can be determined independently and can be substituted in the range of 0 to 4. The substituents are preferably those described above, but some of them may be different. Halogen is a fluorine atom, a chlorine atom, an iodine atom or a bromine atom (hereinafter the same in general formula (9)).

Z is a trisubstituted aromatic group having 6 to 20 carbon atoms. Preferred Z is a pyromellitic group, a polycyclic aromatic group such as a naphthylene group, a fluorenylene group, a benzofluorenylene group or an anthracenylene group or a substituted derivative thereof, or a group represented by the following general formula (10). is there. Examples of the substituent in the substituted derivative of the polycyclic aromatic group include halogen, an alkyl group having 1 to 10 carbon atoms, or a fluorinated product thereof.

In the general formula (10), D is a covalent bond, C (R ² ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, N (R ³ ) _Two groups or a combination thereof, and m is an integer of 1 to 10. R ² is independently a hydrogen atom or a C (R ⁴ ) ₃ group. R ³ is independently a hydrogen atom, an alkyl group having 1 to about 20 carbon atoms, or an aryl group having about 6 to about 20 carbon atoms. Each R ⁴ is independently a hydrogen atom, a fluorine atom or a chlorine atom.

Moreover, what has a unit represented by the following general formula (11), (12) as a polyimide other than the above can be mentioned. Among these, polyimide having a unit represented by the general formula (13) is preferable.

In the general formulas (11), (12), and (13), T and L are halogen, an alkyl group having 1 to 3 carbon atoms or a halide thereof, phenyl substituted by one or more of them. Group or an unsubstituted phenyl group. The halogen is a fluorine atom, a chlorine atom, an iodine atom or a bromine atom (hereinafter the same in general formulas (11), (12) and (13)). z is an integer of 0-3.

G and J are a covalent bond or a bond bond, CH ₂ group, C (CX ₃ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, or N ( CH ₃ ) group. X in the C (CX ₃ ) ₂ group is a hydrogen atom or halogen (hereinafter the same in general formulas (11), (12), and (13)).

A is a hydrogen atom, a halogen, an alkyl group or a halide thereof, a nitro group, a cyano group, a thioalkyl group, an alkoxy group or a halide thereof, an aryl group or a halide thereof, or an alkyl ester group or a substituted derivative thereof.

R is a hydrogen atom, a substituted phenyl group such as a halogen, a phenyl group or a halide thereof, or a substituted alkyl group such as an alkyl group or a halide thereof. n is an integer of 0 to 4, p is an integer of 0 to 3, and q is an integer of 1 to 3.

In the general formulas (11), (12), and (13), when a plurality of T, A, R, or L are present in the molecule, they may be the same or different. Also good. Similarly, z, n, and m may be the same or different. In this case, T, A, R, L, z, n, and m are determined independently.

The polyimides represented by the general formulas (9), (11), (12), and (13) may be composed of the same repeating unit, or have two or more different repeating units. It may be. The different repeating unit may be formed by copolymerizing one or more of acid dianhydrides and / or diamines other than those described above. As the diamine, an aromatic diamine is particularly preferable. When it has the latter different repeating unit, each repeating unit may exist in a block shape or may exist randomly.

Examples of the acid dianhydride for forming the different repeating units include pyromelt acid dianhydride, 3,6-diphenylpyromelt acid dianhydride, and 3,6-bis (trifluoromethyl) pyromelt acid dianhydride. 3,6-dibromopyromelt acid dianhydride, 3,6-dichloropyromelt acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′ , 4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylcarboxylic dianhydride, bis (2 , 3-dicarbophenyl) methane dianhydride.

Also, bis (2,5,6-trifluoro-3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3- Hexafluoropropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride (4,4′-oxydiphthalic anhydride), bis (3,4-dicarboxyphenyl) sulfone dianhydride (3,3 3 ', 4,4'-diphenylsulfonetetracarboxylic anhydride), 4,4'-[4,4'-isopropylidene-di (p-phenyleneoxy)] bis (phthalic anhydride) is An example of an anhydride is given.

Furthermore, N, N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl) diethylsilane dianhydride, 2,3,6,7-naphthalene-tetra Naphthalenetetracarboxylic acids such as carboxylic dianhydrides, 1,2,5,6-naphthalene-tetracarboxylic dianhydrides, 2,6-dichloro-naphthalene-1,4,5,8-tetracarboxylic dianhydrides Acid dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride and pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyridine-2,3,5,6-tetra Heterocyclic aromatic tetracarboxylic dianhydrides such as carboxylic dianhydrides are also examples of the acid dianhydrides.

Preferably used acid dianhydrides are 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-dichloro-4,4 ′, 5,5 ′. -Biphenyltetracarboxylic dianhydrides, 2,2'-substituted dianhydrides such as 2,2'-trihalo-substituted dianhydrides, especially 2,2-bis (trifluoromethyl) -4,4 ' , 5,5'-biphenyltetracarboxylic dianhydride is preferred.

On the other hand, examples of the diamine for forming the different repeating units include (o, m or p-) phenylenediamine, 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 1,4- Benzenediamine such as diamino-2-phenylbenzene, 1,3-diamino-4-chlorobenzene, 4,4′-diaminobiphenyl, 4,4-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 2 , 2-bis (4-aminophenyl) -1,1,1,1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis ( 3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) ) Benzene, and the like.

4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 2,2-bis (4- [4-aminophenoxy) phenyl] propane, 2,2 -Bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenylthioether, 4,4′-diaminodiphenylsulfone 2,2′-diaminobenzophenone, 3,3′-diaminobenzophenone, naphthalenediamine such as 1,8-diaminonaphthalene and 1,5-diaminonaphthalene, 2,6-diaminopyridine and 2,4-diaminopyridine, Heterocyclic aromatic diamines such as 1,4-diamino-S-triazine are also examples of the diamines described above.

Examples of polyimides that can be preferably used include 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenyl. Heat-resistant and solvent-soluble polyimides prepared using aromatic dianhydrides such as propane dianhydride, naphthalenetetracarboxylic dianhydride and bis (3,4-dicarboxyphenyl) sulfone dianhydride It is.

Examples of diamines include 4,4- (9-fluorenylidene) -dianiline, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, and 3,3′-dichloro-4,4′-diamino. Diphenylmethane, 2,2′-dichloro-4,4′-diaminobiphenyl, 2,2 ′, 5,5′-tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, etc. A heat-resistant and solvent-soluble polyimide prepared using an aromatic diamine can be preferably used.

On the other hand, the above-mentioned polyamideimide or polyesterimide is not particularly limited, and one or more suitable types can be used. Of these, polyamide imides described in JP-A No. 61-162512 and polyester imides described in JP-A No. 64-38472 can be preferably used.

The molecular weight of the solid polymer for forming the polymer layer B is not particularly limited, but is preferably soluble in a solvent. In particular, from the viewpoints of coating film thickness system, surface accuracy or surface smoothness, film strength, prevention of cracking due to expansion and contraction when it is made into a film, solubility in solvents (preventing gelation), etc. Based on the weight average molecular weight, 10,000 to 1,000,000, especially 20,000 to 500,000, particularly 50,000 to 200,000 are preferable. The weight average molecular weight is a value measured by gel permeation chromatography (GPC) using polyethylene oxide as a standard sample and a dimethylformamide solvent.

For the formation of the polymer layer B, solid polymers such as the above-mentioned polyaryletherketone, polyamide, polyester, and polyimide may be used alone, or two or more of the same types may be mixed and used. Further, for example, a mixture of two or more polymers having different functional groups, such as a mixture of polyaryl ether ketone and polyamide, may be used.

Moreover, you may use together 1 type, or 2 or more types of appropriate polymers other than the above in the range which the orientation of the said solid polymer which forms the polymer layer B does not fall remarkably. Incidentally, examples of the combined polymer include polyethylene, polypropylene, polystyrene, polymethyl methacrylate, ABS resin and AS resin, polyacetate, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyethersulfone, polyketone, polyimide, Examples thereof include thermoplastic resins such as polycyclohexanedimethanol terephthalate, polyarylate, and liquid crystal polymer (including a photopolymerizable liquid crystal monomer).

Thermosetting resins such as epoxy resins, phenol resins, and novolac resins are also examples of the combined polymer. The amount of the combined polymer used is not particularly limited as long as the orientation is not significantly lowered, but is usually 50% by weight or less, especially 40% by weight or less, particularly 30% by weight or less.

For liquefaction of the solid polymer forming the polymer layer B, an appropriate method such as a method of heating and melting the thermoplastic polymer or a method of dissolving the solid polymer in a solvent to form a solution can be employed. Accordingly, the development layer can be solidified by cooling the development layer in the former melt and by drying the solvent after removing the solvent from the development layer. In forming the polymer layer B, various additives including stabilizers, plasticizers, metals, and the like can be blended as necessary.

For the drying, one or more of appropriate methods such as a natural drying (air drying) method, a heat drying method, particularly a heat drying method at 40 to 200 ° C., and a vacuum drying method can be adopted. From the viewpoint of suppressing production efficiency and generation of optical anisotropy, a method of applying a polymer solution is preferable.

Examples of the solvent include chloroform, dichloromethane, carbon tetrachloride and dichloroethane, tetrachloroethane and trichloroethylene, halogenated hydrocarbons such as tetrachloroethylene, chlorobenzene and orthodichlorobenzene, phenols such as phenol and parachlorophenol, benzene and toluene, Aromatic hydrocarbons such as xylene, methoxybenzene, 1,2-dimethoxybenzene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, ketones such as N-methyl-2-pyrrolidone, acetic acid Examples include esters such as ethyl and butyl acetate.

Further, alcohols such as t-butyl alcohol and glycerin, ethylene glycol and triethylene glycol, ethylene glycol monomethyl ether and diethylene glycol dimethyl ether, propylene glycol and dipropylene glycol and 2-methyl-2,4-pentanediol, dimethylformamide and dimethyl Examples of the solvent include amides such as acetamide, nitriles such as acetonitrile and butyronitrile, ethers such as diethyl ether, dibutyl ether and tetrahydrofuran, methylene chloride, carbon disulfide, ethyl cellosolve and butyl cellosolve.

A solvent can be used individually or in mixture of 2 or more types in an appropriate combination. From the viewpoint of coating viscosity and the like, the solution is preferably a solution in which 2 to 100 parts by weight, especially 5 to 50 parts by weight, especially 10 to 40 parts by weight of the solid polymer is dissolved with respect to 100 parts by weight of the solvent.

For the development of the liquefied polymer, for example, spin coating method, roll coating method, flow coating method, printing method, dip coating method, casting film forming method, casting method such as bar coating method and gravure printing method, extrusion method, etc. The appropriate film forming method can be adopted. In particular, a solution film forming method such as a casting method can be preferably applied from the viewpoint of mass production of a film having little thickness unevenness and alignment strain unevenness.

The polymer layer B which is more preferable than the optical compensation effect and the like satisfies Re = 80 nm or less, especially 2 to 60 nm, particularly 3 to 50 nm, and Rz / Re = 6 to 80, especially 7 to 60, especially 8 to 50. To do.

The polymer layer B may be subjected to a treatment for orienting molecules in the plane as necessary for the purpose of controlling the Re or the like after the development layer is solidified. That is, in a state where the spreading layer is only solidified, it is normal that Re is small with nx≈ny> nz. Incidentally, when the layer thickness is 10 μm, Re is typically 30 nm or less, and in particular 1 to 20 nm.

On the other hand, by performing the above-described alignment treatment, the accuracy of the alignment axis in the plane can be increased, and the characteristic of nx> ny> nz can be imparted, and particularly Re can be increased. Therefore, phase difference characteristics such as Rz / Re can be controlled.

The treatment for orienting molecules in the plane can be performed as a stretching treatment or / and a shrinking treatment. For the stretching treatment, one or two or more suitable methods such as a biaxial stretching method such as a sequential method or a simultaneous method, a uniaxial stretching method such as a free end method or a fixed end method can be applied. The uniaxial stretching method is preferable from the viewpoint of suppressing the bowing phenomenon.

On the other hand, the shrinkage treatment can be performed by, for example, a method in which a polymer layer B is applied and formed on a base material, and a shrinkage force is applied using a dimensional change accompanying a temperature change of the base material. In that case, it is also possible to use a base material imparted with a shrinking ability such as a heat-shrinkable film. At that time, it is desirable to control the shrinkage rate using a stretching machine or the like.

A preferred formation method of the polymer layer B is that a polymer solution dissolved in a solvent and liquefied is spread on a supporting substrate and dried, and if necessary, the solidified product is stretched or contracted through the supporting substrate. This is a method of applying one or both. According to this method, the polymer layer B can be processed in a state of being supported by the base material, and the manufacturing efficiency and processing accuracy are excellent, and continuous manufacturing is also possible.

An appropriate material can be used for the support substrate, and there is no particular limitation. The polymer layer B can be used as an integrated product with the supporting substrate. In that case, the phase difference which arose in the support base material by the extending | stretching process etc. can also be utilized . As the support substrate, a transparent polymer substrate is preferably used.

By the way, examples of the above-mentioned polymer base material that can be formed include the above-mentioned polymer-based stretched film A, those exemplified for solid polymers, acetate-based polymers, polyethersulfone and polysulfone, polycarbonate and polynorbornene, polyolefin and acrylic polymer, Cellulosic resin, polyarylate, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, liquid crystal polymer, or acrylic, urethane, acrylic urethane, epoxy, silicone, etc. Etc.

Further, polymers described in JP-A No. 2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted or / and unsubstituted imide group in the side chain, and (B) a substituted or / and substituted side chain. The resin composition containing A and B with a thermoplastic resin having an unsubstituted phenyl group and a nitrile group can also be used for forming a polymer substrate. Incidentally, a specific example of such a resin composition is a resin composition containing an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer substrate can be obtained as a film comprising a mixed extruded product of the resin composition. From the viewpoint of suppressing the influence of the retardation due to the support base material, an isotropic material such as an acetate polymer is preferable.

The optical compensation polarizing plate can be formed by laminating the retardation plate of the present invention consisting of both the polymer-based stretched film A and the polymer layer B on one side of the polarizing plate through an adhesive layer or an adhesive layer as necessary. It can be preferably used for compensation of phase difference due to birefringence for the purpose of expanding the viewing angle of the liquid crystal cell and improving the contrast. In practical use, for example, an adhesive layer or a pressure-sensitive adhesive layer can be provided on one side or both sides for the purpose of bonding to other members such as a liquid crystal cell.

For the formation of the above-mentioned adhesive layer, for example, a transparent adhesive using an appropriate polymer such as an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether or synthetic rubber can be used. In particular, acrylic pressure-sensitive adhesives are preferred from the viewpoints of optical transparency, pressure-sensitive adhesive properties, weather resistance, and the like.

Appropriate addition of fillers and pigments such as natural and synthetic resins, glass fibers and glass beads, metal powders and other inorganic powders, colorants and antioxidants as necessary An agent can also be blended. Moreover, it can also be set as the adhesion layer which contains transparent fine particles and shows light diffusibility. When the pressure-sensitive adhesive layer is exposed on the surface, it is preferable to temporarily attach a separator or the like to prevent contamination of the pressure-sensitive adhesive layer surface until it is put to practical use.

Examples of the transparent fine particles include inorganic materials such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle diameter of 0.5 to 20 μm. One kind or two or more kinds of suitable fine particles, such as crosslinked fine particles or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate or polyureta can be used.

The optical compensation polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like, but by laminating in advance, the liquid crystal display device is excellent in quality stability, laminating workability, etc. There is an advantage that the manufacturing efficiency can be improved. There are no particular limitations on the angle of arrangement of the optical axes such as the fast axis and the transmission axis of the retardation layers A and B and the polarizing plate during the lamination, and can be determined as appropriate. In general, the transmission axis of the polarizing plate and the nx direction of the retardation layer are arranged in a parallel relationship or an orthogonal relationship to control the characteristics in the perspective direction without affecting the characteristics in the front direction, thereby increasing the viewing angle, etc. It is preferable from the point of aiming.

For the formation of the optical compensation polarizing plate, an appropriate polarizing plate can be used, and the type thereof is not particularly limited. Adsorb dichroic substances such as iodine and / or dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Such as a polarizing film made of a polyene-oriented film such as a stretched film, a cross-linked film, a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product, and so on, when linear light is incident, it transmits linearly polarized light. Absorptive polarizing plates exhibiting characteristics can be preferably used from the viewpoint of achieving a high degree of polarization. The thickness of the polarizing film is generally 1 to 80 μm, but is not limited thereto.

The polarizing plate may be a polarizing film provided with a transparent protective layer on one side or both sides, or a wire grid polarizer. The transparent protective layer is provided for various purposes such as reinforcement of the polarizing film, improvement of heat resistance and moisture resistance, and the formation thereof includes a polymer having excellent transparency, mechanical strength, thermal stability, moisture shielding properties, etc. Preferably used. Incidentally, examples thereof include those exemplified for the above-mentioned support substrate. A particularly preferred transparent protective layer from the viewpoint of polarization characteristics and durability is a triacetyl cellulose film whose surface is saponified with alkali or the like.

The thickness of the transparent protective layer is arbitrary, but is generally 200 μm or less, in particular 5 to 150 μm, particularly 10 to 100 μm for the purpose of reducing the thickness of the polarizing plate. In addition, when providing a transparent protective layer on both sides of a polarizing film, it can also be set as the transparent protective layer which consists of a polymer etc. which are different in the front and back.

The transparent protective layer can be formed as a resin coating layer, a resin film laminate layer, or the like, and the surface thereof may be formed in a fine uneven structure by containing transparent fine particles. In addition, the transparent protective layer can also serve as the polymer-based stretched film A or the support substrate-integrated polymer layer B. In that case, the optical compensation polarizing plate, and thus the liquid crystal display device can be made thinner. . For the transparent fine particles, those exemplified above can be used. The amount of the transparent fine particles used is generally 2 to 70 parts by weight, especially 5 to 50 parts by weight per 100 parts by weight of the transparent resin.

The above-mentioned laminating process of the resin film is not limited. For example, an adhesive made of an acrylic polymer or a vinyl alcohol polymer, or a vinyl alcohol polymer such as boric acid, borax, glutaraldehyde, melamine, or oxalic acid. It can be carried out through an adhesive comprising at least a water-soluble crosslinking agent. As a result, it is difficult to peel off due to the influence of humidity and heat, and the light transmittance and the degree of polarization can be improved. Such an adhesive layer is formed as a coating / drying layer of an aqueous solution, and other additives and catalysts such as an acid can be blended as necessary when preparing the aqueous solution. In particular, it is preferable to use a polyvinyl alcohol-based adhesive from the viewpoint of excellent adhesiveness with a polyvinyl alcohol-based film.

Appropriate methods can be employed for forming the optical compensation polarizing plate, and therefore various forms of optical compensation polarizing plates can be produced. Incidentally, examples thereof are shown in FIGS. 1 to 4 ( b, d, h, j ). 3 is a polarizing film, 7 is a polymer based stretched film A, 9 polymer layer B, 1, 5 is a transparent protective layer, 2, 4, 6 is an adhesive layer or adhesive layer.

1 and 2 show a case where a polarizing plate is used in which transparent protective layers 1 and 5 are provided on both sides of the polarizing film 3 via adhesive layers 2, 4 and 6. 1, 2, 3 and 4 show a polarizing plate provided with both a polymer stretched film A7 and a polymer layer B9. As is clear from the example in the drawing, either of the polymer stretched film A7 and the polymer layer B9 may be located on the polarizing plate side.

As shown in FIGS. 3 and 4 , the optical compensation polarizing plate may have a configuration in which the polymer-based stretched film A <b> 7 serves as the transparent protective layer of the polarizing plate. The polymer stretched film A is a laminate of the polymer stretched film A and the polymer layer B9 .

In forming the optical compensation polarizing plate, the polarizing plate, the polymer-based stretched film A, and the polymer layer B can be laminated in an appropriate order to obtain a desired form. Incidentally, (b), (d), (h), and (j) are obtained by adhering a laminated polymer film A7 and a polymer layer B9 in advance through adhesive layers 4 and 6 and the like.

In the above case, the laminated body of the polymer-based stretched film A and the polymer layer B has a polymer-based stretched film A7 as a supporting substrate as shown in (b), (d), (h), (j) and a polymer layer B9. Attached .

In the, (b) in the form of such as through an adhesive layer 6 or the like to bond the polymeric stretched film A7 a polarizing plate, also be formed by a method in which attaching a polymer layer B9 to the polymeric stretched film A Can do. Further, (b), (d), (h), and (j) are formed in such a manner that a polymer-based stretched film A7 and a polymer layer B9 are provided by a method according to the above, and then the polarizing film 3 or the transparent protective layer 5 is provided. It can also be formed by a method of adhering to.

Note the formation of the laminate of the above as polymeric stretched film A and the polymer layer B, the polymer layer B is coated formed on it a polymeric stretched film A as a supporting base material, in this case, the polymer It is also possible to change the supporting base material to the polymer-based stretched film A by adding a stretching treatment in the drying step of the coating layer that will form the layer B.

An appropriate adhesive such as an acrylic or silicone-based, polyester-based, polyurethane-based, polyether-based, or rubber-based transparent pressure-sensitive adhesive can be used for the above-described bonding treatment, if necessary. In view of preventing changes in the optical characteristics of the constituent members, those that do not require a high-temperature process during curing and drying are preferred, and those that do not require a long curing process or drying time are desirable. An adhesive that does not peel off under heating or humidification conditions is preferably used.

In the above, the polarizing plate forming the optical compensation polarizing plate is one in which a hard coat treatment, an antireflection treatment, an antisticking treatment, a treatment for diffusion or antiglare, etc. are performed on the side where the retardation layer is not provided. There may be. Hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, hardness and slipperiness due to appropriate ultraviolet curable resins such as silicone, urethane, acrylic and epoxy are used. It can be formed by a method of adding an excellent cured film or film to the surface of the transparent protective layer.

On the other hand, the antireflection treatment is performed for the purpose of preventing the reflection of external light on the surface of the polarizing plate. For example, a light-interfering film such as a coating layer of a fluorine-based polymer or a multilayer metal vapor-deposited film or the like It can be suitably formed as a film made of an antireflection film.

On the other hand, the anti-sticking is for the purpose of preventing adhesion with the adjacent layer, and the anti-glare layer is applied for the purpose of preventing the external light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, by applying a fine uneven structure to the surface by an appropriate method such as the resin coating layer containing transparent fine particles, embossing, sand blasting, etching, etc. It can be formed by a method.

The anti-glare layer may also serve as a diffusion layer (such as a viewing angle compensation function) for diffusing the light transmitted through the polarizing plate to expand the viewing angle. The hard coat layer, antireflection layer, anti-sticking layer, diffusion layer or anti-glare layer is provided as an optical layer composed of a sheet provided with these layers as a separate layer from the transparent protective layer. You can also

The optical compensation polarizing plate according to the present invention can be preferably used for forming various display devices such as a liquid crystal display device. In the application, one of other optical layers such as a reflection plate, a semi-transmission reflection plate, a brightness enhancement film, another retardation plate, a diffusion control film, a polarization scattering film, etc. is passed through an adhesive layer or an adhesive layer as necessary. It can also be used as an optical member formed by laminating layers or two or more layers. For the lamination, an appropriate bonding means such as the above-mentioned adhesive layer can be used.

The reflection plate is used to form a reflective polarizing plate by providing it on a polarizing plate. The reflective polarizing plate is usually disposed on the back side of the liquid crystal cell, and forms a liquid crystal display device (reflective liquid crystal display device) of a type that reflects incident light from the viewing side (display side) and displays it. Therefore, there is an advantage that it is possible to omit a built-in light source such as a backlight and to easily reduce the thickness of the liquid crystal display device.

The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary. Specific examples thereof include those in which a foil or a vapor deposition film made of a reflective metal such as aluminum is attached to one side of a transparent protective layer that is matted as necessary.

The reflective layer may be a light diffusion type. The light diffusion type reflective layer can be obtained, for example, by a method of forming a reflective layer reflecting the fine concavo-convex structure on a transparent protective layer containing transparent fine particles and having a surface having a fine concavo-convex structure. A reflective layer having a fine surface irregular structure has the advantage of diffusing incident light by irregular reflection, preventing directivity and glaring appearance, and suppressing uneven brightness.

The reflective layer reflecting the fine concavo-convex structure is formed by attaching a metal reflective layer on the fine concavo-convex structure by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method, or a plating method. Can be formed.

In addition, it can replace with the system attached directly to the transparent protective layer of an above-described polarizing plate, and a reflection layer can also be provided as a reflection sheet etc. which attaches a reflection layer to an appropriate film. The reflective layer made of metal is used in a state in which the reflective surface is covered with a film, a polarizing plate, etc., to prevent a decrease in reflectance due to oxidation, and in turn, to maintain the initial reflectance for a long period of time. It is preferable from the viewpoint of avoiding the above.

Further, the reflective layer may be a semi-transmissive type made of a half mirror or the like that reflects and transmits light. A transflective polarizing plate is also usually provided on the back side of a liquid crystal cell. When a liquid crystal display device is used in a relatively bright atmosphere, display is achieved by reflecting external incident light from the viewing side (display side). In a relatively dark atmosphere, a display device or the like that achieves display using a built-in light source such as a backlight disposed behind the transflective polarizing plate is formed.

Therefore, the transflective polarizing plate can save energy by using a light source such as a backlight in a bright atmosphere, and is useful for forming a display device that can be used with a built-in light source even in a relatively dark atmosphere.

On the other hand, the above-described brightness enhancement film is used for the purpose of improving brightness by suppressing absorption loss due to a polarizing plate. An appropriate film can be used as the brightness enhancement film. By the way, as an example, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films with different refractive index anisotropy, it shows the characteristic of transmitting linearly polarized light with a predetermined polarization axis and reflecting other light. (For example, “D-BEF” manufactured by 3M).

Other examples of brightness enhancement films include cholesteric liquid crystal layers, especially cholesteric liquid crystal polymer alignment films and films in which the alignment liquid crystal layer is supported on a film substrate (for example, “PCF350” manufactured by Nitto Denko Corporation, Merck Such as “Transmax” and the like, which reflects either one of the left-handed and right-handed circularly polarized light and transmits the other light. The latter cholesteric liquid crystal system can be used in combination with a quarter-wave plate as needed for the purpose of converting circularly polarized light into linearly polarized light.

Further, as the retardation plate, in addition to the above-mentioned quarter wavelength plate, various positions such as a stretched film of various polymers by an appropriate method such as uniaxial or biaxial, a polymer film subjected to Z-axis alignment treatment, a liquid crystalline polymer layer, etc. Those having a phase difference can be used. The diffusion control film is used for the purpose of controlling glare related to viewing angle and resolution, scattered light, and the like, and an optical functional film utilizing diffusion, scattering, and / or refraction is used. Furthermore, the polarization scattering film is a film in which a scattering substance is contained in the film so that the polarized light has scattering anisotropy depending on the vibration direction, and is used for controlling the polarization.

The above-described optical member in which two or more optical layers are laminated can be formed by a method of separately laminating sequentially in the manufacturing process of a liquid crystal display device or the like. The product has the advantage of improving the production efficiency of the liquid crystal display device and the like by being excellent in the stability of quality and the assembly workability.

The optical compensation polarizing plate and the optical member according to the present invention may be provided with a pressure-sensitive adhesive layer or an adhesive layer on a necessary surface for bonding with other members such as other optical layers and liquid crystal cells. The adhesive layer can be formed according to the above. In particular, the moisture absorption rate is low in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties due to thermal expansion differences, prevention of warping of liquid crystal cells, and formation of a display device with high quality and durability. An adhesive layer that is low and excellent in heat resistance can be preferably used. Moreover, it can also be set as the adhesion layer etc. which contain a transparent fine particle and show light diffusibility.

If the pressure-sensitive adhesive layer or adhesive layer provided on the optical compensation polarizing plate or the optical member is exposed on the surface, temporarily cover it with a separator for the purpose of preventing contamination until the pressure-sensitive adhesive layer etc. is put to practical use. Is preferred. The separator is obtained by a method in which a coating layer with an appropriate release agent such as silicone-based, long-chain alkyl-based, fluorine-based, molybdenum sulfide, or the like is provided on an appropriate thin leaf body according to the above-mentioned support base material, if necessary. Can do.

Each layer such as a retardation layer, a polarizing film, a transparent protective layer, and an adhesive layer forming the optical compensation polarizing plate and the optical member described above is, for example, a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, or a cyanoacrylate compound. In addition, a material having an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorber such as a nickel complex compound may be used.

The optical compensation polarizing plate and the optical member according to the present invention can be preferably used for forming various devices such as a liquid crystal display device. For example, a reflective type or a transflective type in which a polarizing plate is arranged on one side or both sides of a liquid crystal cell. Alternatively, it can be used to form a liquid crystal display device such as a transmission / reflection type.

That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an optical compensation polarizing plate, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that the optical compensation polarizing plate or the optical member is provided on at least one side outside the liquid crystal cell.

Therefore, a liquid crystal display device in which an optical compensation polarizing plate is arranged on one or both sides of a liquid crystal cell, a liquid crystal display device using a backlight or a front light in an illumination system, or a transmissive type using a reflective plate or a semi-transmissive reflective plate An appropriate liquid crystal display device such as a reflection type or a reflection / transmission type can be formed.

The optical compensation polarizing plate is preferably arranged such that the retardation layer is positioned between the liquid crystal cell on the viewing side or / and the back side and the polarizing plate, particularly between the polarizing plate on the viewing side. . In the arrangement, the optical member described above can also be used.

The liquid crystal cell forming the liquid crystal display device is arbitrary, for example, an active matrix driving type represented by a thin film transistor type, a simple matrix driving type represented by a twist nematic type or a super twist nematic type, or a VA type. Alternatively, a liquid crystal cell of an appropriate type such as an OCB type may be used. When the optical compensation polarizing plate and the optical member are provided on both sides of the liquid crystal cell, they may be the same or different.

In the above, the liquid crystal display device forming components may be laminated and integrated, or may be in a separated state. In forming the liquid crystal display device, for example, an appropriate optical element such as a prism array sheet, a lens array sheet, a light diffusing plate, or a protective plate can be appropriately disposed. Such an element can also be used for the formation of a liquid crystal display device in the form of the above-described optical member laminated with an optical compensation polarizing plate.

Reference example: 80 [mu] m thick via a PVA adhesive having a thickness of 5 [mu] m on both sides of a polarizing film obtained by uniaxially stretching a 80 [mu] m thick polyvinyl alcohol (PVA) film in an aqueous iodine solution 5 times. A triacetyl cellulose (TAC) film was adhered to obtain a polarizing plate having a thickness of 190 μm .

Example 1
Weight average molecular weight of 59,000 synthesized from 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl A 15 wt% cyclohexanone solution of polyimide was applied onto a TAC film having a thickness of 80 μm, dried, and then subjected to transverse stretching with a TAC film through a tenter to obtain a retardation plate having a thickness of 73 μm. This is a TAC stretched film having Re of 30 nm and Rz of 38 nm (Rz / Re = 1.3), and a polymer layer having Re of 22 nm and Rz of 200 nm (Rz / Re = 9.1) adhered. It was. Next, it was adhered to one side of the same polarizing film as in Example 1 with a PVA adhesive having a thickness of 5 μm so that the polymer layer was on the outside, and a TAC film having a thickness of 80 μm was attached to the other side of the polarizing film. Bonding was performed in the same manner to obtain an optical compensation polarizing plate having a total thickness of 183 μm.

Example 2
An optical compensation polarizing plate having a total thickness of 183 μm was obtained in the same manner as in Example 1 except that the front and back of the retardation plate were reversed and adhered so that the polymer layer was on the inside.

Example 3
A polyimide solution according to Example 1 was applied onto a TAC film having a thickness of 80 μm, and in the drying process, 10% longitudinal stretching was performed in the film flow (long length) direction to obtain a retardation film having a thickness of 83 μm. It was. This was a polymer layer of Re 40 nm and Rz 200 nm (Rz / Re = 5) made of polyimide adhered on a TAC stretched film of Re 25 nm and Rz 42 nm (Rz / Re = 1.7). Then, it was bonded to one side of the polarizing plate with an acrylic pressure-sensitive adhesive so that the polymer layer was on the outside, and an optical compensation polarizing plate was obtained according to Example 1 .

Example 4
5. Weight average molecular weight synthesized from 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride and 2,2′-dichloro-4,4′-diaminobiphenyl. A 20% by weight solution obtained by dissolving 20,000 polyimide in cyclopentanone was applied to a 80 μm thick triacetylcellulose film, and the film was stretched 1.2 times with a tenter during the drying process. A retardation plate having a thickness of 65 μm was obtained. This was a polymer layer of Re 5 nm and Rz 220 nm (Rz / Re = 44) made of polyimide in close contact with a TAC stretched film of Re 22 nm and Rz 45 nm (Rz / Re = 2.0). Then, it was bonded to one side of the polarizing plate with an acrylic pressure-sensitive adhesive so that the polymer layer was on the outside, and an optical compensation polarizing plate was obtained according to Example 1 .

The liquid crystal display device is formed by arranging the optical compensation polarizing plate and the polarizing plate obtained in the evaluation test examples and reference examples in various combinations so that the slow axis is perpendicular to the viewing side and the back side of the VA liquid crystal cell. A viewing angle with a contrast ratio of 10 or more was examined in each of the vertical and horizontal directions, diagonal a (45 degrees and -225 degrees) and diagonal b (135 degrees and -315 degrees). The optical compensation polarizing plate was arranged so that the retardation layer was on the cell side.

The results are shown in the following table.
[Table 1]
Arrangement Object angle (degree)
Visual recognition Side back side Up / down direction Left / right diagonal direction a direction diagonal b direction Example 1 Reference Example Example 1 ± 80 ± 80 ± 65 ± 65
Example 2 Reference Example Example 2 ± 80 ± 80 ± 65 ± 65
Example 3 Reference Example Example 3 ± 80 ± 80 ± 65 ± 65
Example 4 Reference Example Example 4 ± 80 ± 80 ± 60 ± 60
Example 5 Reference example Reference example ± 40 ± 40 ± 30 ± 30

It can be seen from the table that in all of Examples 1 to 4 corresponding to the examples, the viewing angle having a contrast ratio of 10 or more is doubled or larger based on the angle as compared with Example 5 as a comparative example. From this, it can be seen that with the optical compensation polarizing plate according to the present invention, a high-quality liquid crystal display device having excellent visibility can be obtained by optically compensating the liquid crystal cell.

Cross section of an example of an optical compensation polarizing plate Cross-sectional view of another optical compensation polarizing plate example Sectional view of still another example of an optical compensation polarizing plate Sectional view of still another example of an optical compensation polarizing plate

Explanation of symbols

1, 5: Transparent protective layer
2, 4, 6: Adhesive layer (adhesive layer)
3: Polarizing film (polarizing plate)
7: Polymer stretched film A
9: Polymer layer B

Claims (6)

A method for producing a retardation plate comprising a polymer-based stretched film A and a polymer layer B,
(1) a step of preparing a support substrate made of a polymer;
(2) At least one of a solution and a melt of at least one polymer selected from the group consisting of polyetherketone, polyamide, polyester, polyimide, polyamideimide, and polyesterimide is spread on the support substrate and applied. Forming a layer;
and,
(3) By stretching or shrinking the supporting substrate and the coating layer together, the supporting substrate becomes the polymer stretched film A, the coating layer becomes the polymer layer B, and the polymer stretched film. A satisfies Re = 20 to 300 nm and Rz / Re = 1.0 to 8, the polymer layer B satisfies Re = 1 to 100 nm and Rz / Re = 5 to 100, and the thickness of the polymer layer B Forming both the layers so that the thickness is 1 to 20 μm,
The manufacturing method of the optical film containing this.

In each layer of the polymer-based stretched film A or the polymer layer B,
The Re is an in-plane retardation of each layer, the Rz is a thickness direction retardation of each layer, and each is represented by the following formula:
In the following formula, nx and ny are in-plane refractive indexes of the respective layers, nz is a refractive index in the thickness direction of the respective layers, and d is a thickness (nm) of the respective layers.

(Nx-ny) d = Re
(Nx-nz) d = Rz In the step (2), the polymer solution is spread on the support substrate to form the coating layer, and in the step (3), the coating layer is dried and solidified to be stretched. Or the manufacturing method of Claim 1 which shrinks. The manufacturing method according to claim 1 or 2, wherein, in the step (3), the polymer-based stretched film A and the polymer layer B are formed by stretching. In the step (2), the polymer solution is spread on the support substrate to form the coating layer, and in the step (3), the support substrate and the support layer are dried while the coating layer is dried. The manufacturing method of Claim 1 which forms the said polymer-type stretched film A and the said polymer layer B by extending | stretching a coating layer together. The manufacturing method according to claim 1, wherein the support base and the polymer-based stretched film A are made of a cellulose-based resin. A method for producing an optical compensation polarizing plate having a retardation layer on one side of a polarizing plate,
(4) The process of manufacturing a phase difference plate by the manufacturing method in any one of Claims 1-5,
and,
(5) The step of laminating the retardation plate on one side of the polarizing plate via an adhesive layer or an adhesive layer, and using the retardation plate as a retardation layer of the optical compensation polarizing plate,
Manufacturing method.

Images