JP4025699B2 - Liquid crystal panel and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device using the same.

  Conventionally, in a liquid crystal display device, a so-called TN mode in which liquid crystal having positive dielectric anisotropy is horizontally aligned between mutually opposing substrates has been mainly used. However, in the TN mode, due to its driving characteristics, birefringence occurs due to liquid crystal molecules in the vicinity of the substrate even if black display is attempted. As a result, light leakage occurs and it is difficult to perform complete black display. On the other hand, there is a VA mode in which liquid crystal molecules are aligned substantially vertically when no voltage is applied. In the VA mode, light passes through the liquid crystal layer with almost no change in the plane of polarization. Therefore, by disposing polarizing plates above and below the substrate, an almost complete black display can be obtained in a non-driven state (voltage non-applied state). Is possible.

  However, in the VA mode, although almost complete black display is possible in the panel normal direction, when the panel is observed from a direction deviating from the normal direction (oblique direction), light leakage is affected by the birefringence of the liquid crystal. appear. As a result, there is a problem that the viewing angle becomes narrow in the VA mode. In order to solve this problem, it is possible to compensate for the birefringence of the liquid crystal by disposing a retardation plate having a refractive index anisotropy of nx = ny> nz at least one between the liquid crystal layer and the polarizing plate. Have been proposed (for example, Patent Document 1). The nx, ny, and nz represent refractive indexes in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, in the retardation plate. The X-axis direction is an axial direction showing the maximum refractive index in the in-plane direction of the retardation plate, and the Y-axis direction is an axial direction perpendicular to the X-axis direction in the plane, The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction. However, even if the birefringence of the liquid crystal layer is compensated, there is a problem in that light leakage by the polarizing plate occurs in the orientation deviating from the optical axis of the polarizing plate, resulting in a decrease in contrast. Basically, even if a crossed nicols state is obtained with polarizers in which a dichroic substance such as iodine is adsorbed on a PVA film, the viewing angle is tilted from the normal direction in the direction shifted from the optical axis. This is because light leakage inevitably occurs.

  In contrast, a first retardation plate having a positive refractive index anisotropy satisfying nx> ny = nz and a second retardation having a negative refractive index anisotropy satisfying nx = ny> nz. There has been proposed a method of reducing the light leakage and improving the viewing angle characteristics even in the direction shifted from the optical axis of the polarizing plate by using the plate together (for example, Patent Document 2). However, this method only improves the viewing angle characteristics of the contrast, that is, reduces the amount of leakage with respect to light near 550 nm, which has the highest visibility, and no solution is shown for color shift. . In terms of viewing angle characteristics, it is necessary to reduce the amount of leakage for blue and red light as well, and if that is insufficient, black will be blue or reddish. Will occur. That is, in improving the viewing angle characteristics of contrast, it is necessary to consider the problem of the color shift phenomenon.

  It has also been proposed to improve the viewing angle characteristics of a VA mode liquid crystal display device by using an optically biaxial retardation plate of nx> ny> nz (for example, Patent Document 3). However, the color shift is not sufficient as in the above case.

On the other hand, in a recent study, in a VA mode liquid crystal display device having a reverse dispersion A plate (nx> ny = nz) and a negative C plate (nx = ny> nz), the color shift phenomenon in black display is In particular, it has been reported that it can be improved a little on the short wavelength side (for example, Non-Patent Document 1). However, this method is not sufficient in terms of color shift.
JP-A-62-210423 Patent 3027805 Japanese Patent No. 3330574 Y.Ono, et.al .: IDW'02 Proceedings p525

  The present invention has been made in view of such circumstances, and an object thereof is to provide a VA mode liquid crystal panel having a high contrast ratio over a wide range and suppressing color shift.

To achieve the object, the liquid crystal panel of the present invention is a liquid crystal panel including two polarizing plates, a birefringent layer A, a birefringent layer B, and a liquid crystal cell C,
The two polarizing plates are arranged so that their absorption axes are substantially orthogonal,
Between the two polarizing plates, the birefringent layer A, the birefringent layer B and the liquid crystal cell C are disposed,
The birefringent layer A has a refractive index anisotropy of the following formula (1):
The birefringent layer B has a refractive index anisotropy of the following formula (2), and the material for forming the birefringent layer B is 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane. ) And 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl),
The liquid crystal cell C is a liquid crystal cell in which the liquid crystal molecules are aligned substantially vertically with no voltage applied.
The wavelength dispersion characteristics of the birefringent layer A (α40 (A)), the birefringent layer B (α40 (B)), and (α40 (C)) of the liquid crystal cell C are expressed by the following formulas (3) and ( 4) satisfying the condition of
It is a liquid crystal panel.

Formula (1) nx> ny ≧ nz
Formula (2) nx ≧ ny> nz

In the formula (1) and the formula (2), nx, ny, and nz represent the refractive indexes in the X-axis direction, the Y-axis direction, and the Z-axis direction in the birefringent layers A and B, respectively. The X-axis direction is an axial direction that exhibits the maximum refractive index in each in-plane direction of the birefringent layers A and B, and the Y-axis direction is relative to the X-axis direction in each of the planes. The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction.

Formula (3) α40 (B)> α40 (C)> α40 (A)
Formula (4) 1> α40 (A)

In the formula (3) and the formula (4), as shown in the following formula (5), the wavelength dispersion characteristic α40 is based on the normal direction of the birefringent layer surface or the liquid crystal cell surface as a reference (0 °). It is the ratio of retardation (Re) measured with incident light of each wavelength of 430 nm and 550 nm from a direction inclined by 40 °.

Formula (5) α40 = Re (430 nm) / Re (550 nm)
Re (430 nm): Retardation measured with incident light having a wavelength of 430 nm Re (550 nm): Retardation measured with incident light having a wavelength of 550 nm

  The present inventors have made a series of studies in order to solve the above problems. In the process, attention was paid to the transparent protective layer used for the polarizing plate. That is, in order to obtain a VA mode liquid crystal display device that suppresses sufficient light leakage for each wavelength, a transparent polymer film (for example, triacetyl) used as a transparent protective film on both sides of the polarizer. It is necessary to pay attention to the optical influence of cellulose (TCA) film. Generally, a transparent polymer film has a refractive index anisotropy of nx ≧ ny> nz even in an unstretched state. In particular, since the thickness direction retardation (nx-nz) d is about 40 to 60 nm, the light propagating in the direction inclined from the film normal is greatly affected. It is necessary to set the phase difference value. Furthermore, in order to protect the liquid crystal molecules in the liquid crystal cell from ultraviolet light, the transparent protective film of the polarizing plate generally contains a UV absorber. Therefore, it was concluded that in order to eliminate the color shift phenomenon of the VA mode liquid crystal display device, it is necessary to set the wavelength dispersion characteristic of the birefringent layer so as to eliminate the optical influence of the UV absorber. . Based on this, as a result of further research, in the VA mode liquid crystal panel, the birefringent layer A of the above formula (1) and the birefringent layer B of the above formula (2) are used, and the liquid crystal cell C And satisfying the relationship of the above formulas (3) and (4), it is found that a VA mode liquid crystal panel having a high contrast ratio over a wide range and capable of effectively suppressing color shift can be provided. Reached. Therefore, the liquid crystal display device including the liquid crystal panel of the present invention has a high contrast ratio and a suppressed color shift over a wide range, and therefore has excellent display quality.

  In the present invention, the angle of incidence of the wavelength dispersion characteristic is set to 40 ° in the above formulas (3) and (4) for the following reason.

  Regarding the incident angle dependency of chromatic dispersion, the liquid crystal molecules used in the cell are greatly different in chromatic dispersion of ordinary light refractive index no and extraordinary light refractive index ne. Therefore, the wavelength dispersion of Δn = ne−no is slightly different depending on the viewing angle. In the VA mode, since the liquid crystal molecules are aligned substantially vertically, Δn = 0 at an incident angle of 0 °, and chromatic dispersion cannot be measured. Therefore, it is necessary to measure in a state where the incident light is tilted so that a phase difference is developed to some extent. However, if the measurement is too large, the accuracy deteriorates due to the influence of surface reflection or the like. For this reason, the incident angle for measuring the wavelength dispersion characteristic is preferably 40 °. On the other hand, in the birefringent layer, the wavelength dispersion of the retardation is almost the same depending on the viewing angle. Considering these things comprehensively, the incident angle is optimally 40 °.

  In the present invention, the difference in refractive index in the plane of the birefringent layer B (Δn = nx−ny, nx and ny are the same as those in the formula (2)) may be in the range of 0.005 to 0.2. For example, the thickness of the birefringent layer B can be reduced, which is preferable from the viewpoint of reducing the thickness and weight of the display device. Furthermore, Δn is preferably in the range of 0.008 to 0.17, and more preferably in the range of 0.01 to 0.15.

  In the present invention, the birefringent layer B is preferably formed from a non-liquid crystalline material. The non-liquid crystalline material is not particularly limited, and examples thereof include polyamide, polyimide, polyester, polyetherketone, polyamideimide and polyesterimide, and these may be used alone or in combination of two or more.

In the present invention, the polarizing plate includes a polarizer and a transparent protective layer laminated on both surfaces thereof, and the transparent protective layer on the liquid crystal cell C side satisfies the conditions of the following formula (6) and the following formula (7). It is preferable to satisfy.

Formula (6) Re = (nx−ny) d <10 nm
Formula (7) Rth = (nx−nz) d <20 nm

In the formula (6) and the formula (7), nx, ny and nz are the same as the formula (1) and the formula (2).

  When the conditions of the formula (6) and the formula (7) are satisfied, the contrast ratio in the oblique direction can be improved without affecting the light transmitted in the oblique direction.

  In the present invention, the birefringent layer A and the birefringent layer B are preferably laminated in this order on one polarizing plate. In this case, the birefringent layer A is laminated on the polarizer of one polarizing plate, the birefringent layer A also serves as the transparent protective layer, and the slow axis of the birefringent layer A and the polarizer More preferably, the birefringent layer B is laminated on the birefringent layer A. Further, the liquid crystal cell C is preferably laminated on the birefringent layer B. That is, when the birefringent layer B and the liquid crystal cell C are adjacent to each other, the optical compensation of the liquid crystal cell C of the birefringent layer B is further improved.

  Next, the present invention will be described in more detail.

  In the liquid crystal panel of the present invention, the birefringent layer A, the birefringent layer B, and the liquid crystal cell C are disposed between two polarizing plates.

  The material for forming the birefringent layer A is not particularly limited as long as it satisfies the formula (1), the formula (3), and the formula (4) and is optically transparent.

  For example, when cellulose acetate is used as the material for forming the birefringent layer A, it is known that the condition of the formula (4) can be satisfied by changing the degree of acetylation.

  As a material for forming the birefringent layer A, for example, a resin blend or copolymer may be used. In the case of a blend, since it is necessary to be optically transparent, it is preferable that the refractive index of each compatible polymer and each polymer is substantially equal. Specific combinations of blends include, for example, poly (methyl methacrylate) as a polymer having negative optical anisotropy, poly (vinylidene fluoride), poly ( Ethylene oxide), a combination of poly (vinylidene fluoride-co-trifluoroethylene), poly (phenylene oxide) as a polymer having positive optical anisotropy, polystyrene as a polymer having negative optical anisotropy, Poly (styrene-co-lauroylmaleimide), poly (styrene-co-cyclohexylmaleimide), poly (styrene-co-phenylmaleimide) combination, poly (styrene-co-maleic anhydride) having negative optical anisotropy ) And positive optical anisotropy polycarbonate, and positive optical anisotropy Poly with (acrylonitrile - - co-butadiene) and a negative optical anisotropy (acrylonitrile - co - styrene) blend combinations of the like. From the viewpoint of transparency, a combination of polystyrene and poly (phenylene oxide) such as poly (2,6-dimethyl-1,4-phenylene oxide) is preferable.

  Examples of the copolymer include poly (butadiene-co-polystyrene), poly (ethylene-co-polystyrene), poly (acrylonitrile-co-butadiene), and poly (acrylonitrile-co-butadiene-co-styrene). Polycarbonate copolymers, polyester copolymers, polyester carbonate copolymers, polyarylate copolymers, and the like. In particular, since a segment having a fluorene skeleton can have negative optical anisotropy, a polycarbonate copolymer, a polyester copolymer, a polyester carbonate copolymer, a polyarylate copolymer, or the like having a fluorene skeleton is preferable.

  The method for producing the birefringent layer A is not particularly limited. For example, a solution in which the forming material is dissolved in a solvent is prepared, and this is applied in a film form to a base film or metal endless belt having a smooth surface. Then, the birefringent layer A may be formed by evaporating and removing the solvent.

  The solvent of the solution to be applied is not particularly limited, and examples thereof include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; phenol, parachlorophenol. Phenols such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene and other aromatic hydrocarbons; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, N-methyl- Ketone solvents such as 2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol Alcohol solvents such as monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol and 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile systems such as acetonitrile and butyronitrile Solvents; ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran; carbon disulfide, ethyl cellosolve, butyl cellosolve, and the like. One type of these solvents may be used, or two or more types may be used in combination.

  Examples of the solution coating method include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. Moreover, in the case of coating, the superposition | polymerization method of a polymer layer is also employable as needed.

  The material for forming the base film is not particularly limited, and a polymer having excellent transparency is preferable, and a thermoplastic resin is preferable because it is suitable for a stretching process and a shrinking process as described later. Specifically, for example, acetate resin such as triacetyl cellulose (TAC), polyester resin, polyethersulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, polynorbornene resin (for example, Trade name “ARTON” (manufactured by JSR Corporation), trade name “ZEONOR”, trade name “ZEONEX” (manufactured by Nippon Zeon Co., Ltd.), cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride Examples thereof include resins, polyvinylidene chloride resins, polyacrylic resins, and mixtures thereof. Moreover, a liquid crystalline polymer etc. can also be used. Further, for example, as described in JP-A-2001-343529 (WO 01/37007), a thermoplastic resin having a substituted imide group or an unsubstituted imide group in the side chain, and a substituted phenyl group in the side chain Alternatively, a mixture of a thermoplastic resin having an unsubstituted phenyl group and a nitrile group can also be used. Specific examples include a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. Among these forming materials, for example, a material capable of setting the birefringence index relatively lower when a transparent film is formed is preferable, and specifically, a substituted imide group or an unsubstituted imide group in the aforementioned side chain. And a mixture of a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in the side chain. Among the above resins, cellulose polymer films such as triacetyl cellulose (TAC), norbornene polymer films (trade name “ARTON” (manufactured by JSR Corporation), trade names “ZEONOR”, trade names “ZEONEX” ( A typical example is Zeon Corporation).

  Although the thickness of the said base film is about 10-1000 micrometers, for example, Preferably it is 20-500 micrometers, More preferably, it is 30-100 micrometers.

  As a method of forming the birefringent layer A as a transparent protective layer of a polarizing plate, for example, the birefringent layer A is formed by applying the coating solution to a polarizer and evaporating and removing the solvent. That's fine.

  In the present invention, the method for forming the birefringent layer A is not particularly limited to the above method.

  Next, the liquid crystal cell C is a liquid crystal cell in which liquid crystal molecules are arranged between two liquid crystal cell substrates, and in a so-called VA mode in which liquid crystal molecules are aligned substantially vertically when no voltage is applied. It is a liquid crystal cell. Examples of the VA mode liquid crystal cell include: (1) A narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when voltage is applied (Japanese Patent Laid-Open (2) includes a liquid crystal cell in which a VA mode is multi-domained for widening the viewing angle. Specifically, MVA (described in SID97, Digest of tech. Papers (Preliminary Collection) 28 (1997) 845, SID99, Digest of tech. Papers (Preliminary Collection) 30 (1999) 206, and Japanese Patent Laid-Open No. 11-258605. , SURVAIVAL (Monthly Display, Vol. 6, No. 3 (1999) 14), PVA (Asia Display 98, Proc. Of the 18th Inter. Display res. Conf. (Preliminary Collection) (1998) 383), Para- A (announced at LCD / PDP International '99), DDVA (SID 98, Digest of tech. Papers (Preliminary Collection) 29 (1998) 838), EOC (SID 98, Digest of tech. Papers (Preliminary Collection) 29 (1998) 319), PSHA (SID 98, Digest of tech. Papers (Preliminary Collection) 29 (1998) 1081), RFFMH (Asia Display 98, Proc. Of the 18th Inter. Display res) Conf. (Preliminary Book) (described in 1998) 375), and HMD (SID 98, Digest of tech. Papers (Preliminary Book) 29 (1998) 702). In addition, (3) a liquid crystal cell (IWD'98, Proc. Of the 5th) in which a rod-like liquid crystal molecule is substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied. Inter. Display Workshop. (Preliminary book) (1998) 143) is also included. Further, the wavelength dispersion characteristic α40 (C) of the liquid crystal cell C is basically larger than 1 because the liquid crystal material used has positive wavelength dispersion.

  Next, the birefringent layer B is not particularly limited as long as it satisfies the formula (2), the formula (3), and the formula (4). In the birefringent layer B, if Δn = nx−ny (nx ≧ ny) is in the range of 0.005 to 0.2, the thickness of the birefringent layer B can be reduced, and the liquid crystal display device It is also preferable in terms of reducing the thickness and weight. Furthermore, Δn is preferably in the range of 0.008 to 0.17, and more preferably in the range of 0.01 to 0.15. Further, since the birefringent layer B and the liquid crystal cell C are adjacent to each other, it is preferable that the difference in phase difference between the two is small. Therefore, in the birefringent layer B, Rth = (nx−nz) d is a liquid crystal cell. It is preferable that 1/2 ≦ Rth ≦ 3/2 of the phase difference of the liquid crystal cell.

  The material for forming the birefringent layer B is not particularly limited, but a non-liquid crystalline material is preferable. Examples of the non-liquid crystalline material include, as described above, polyamide, polyimide, polyester, polyetherketone, polyaryletherketone, polyamide because of excellent heat resistance, chemical resistance, transparency, and high rigidity. Polymers such as imide and polyesterimide are preferred. Any one of these polymers may be used alone, or a mixture of two or more having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. . Among such polymers, polyimide is particularly preferable because of its high transparency, high orientation, and high stretchability.

  The molecular weight of the polymer is not particularly limited. For example, the weight average molecular weight (Mw) is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 2,000 to 500,000. is there.

  As the polyimide, for example, a polyimide that has high in-plane orientation and is soluble in an organic solvent is preferable. Specifically, for example, it includes a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and an aromatic tetracarboxylic dianhydride disclosed in JP-T-2000-511296, and has the following general formula: A polymer containing one or more repeating units shown in (1) can be used.

In the general formula (1), R ³ ~R ⁶ represents a hydrogen atom, a halogen atom, a phenyl group, 1-4 halogen atoms, or C ₁ ~ ₁₀ alkyl-substituted phenyl and C ₁ ~ _10, It is at least one kind of substituent each independently selected from the group consisting of alkyl groups. Preferably, R ³ to R ⁶ is a halogen atom, a phenyl group, each independently from the group consisting of one to four halogen atoms or C ₁ ~ ₁₀ alkyl-substituted phenyl, and C ₁ ~ ₁₀ alkyl group Is at least one type of substituent selected.

In the general formula (1), Z represents a tetravalent aromatic group C ₆ ~ _20, preferably a pyromellitic group, a polycyclic aromatic group, a derivative of a polycyclic aromatic group or, And a group represented by the following general formula (2).

In the general formula (2), Z ′ is, for example, a covalent bond, C (R ⁷ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, or NR ⁸ groups, and when plural, they are the same or different. W represents an integer from 1 to 10. R ⁷ is each independently a hydrogen atom or C (R ⁹ ) ₃ . R ⁸ is an alkyl group of a hydrogen atom, C ₁ ~ ₂₀ or a C ₆ ~ ₂₀ aryl group, and when there are plural, they may be the same or different. R ⁹ is independently a hydrogen atom, a fluorine atom, or a chlorine atom.

Examples of the polycyclic aromatic group include a tetravalent group derived from naphthalene, fluorene, benzofluorene or anthracene. Further, as the substituted derivative of the polycyclic aromatic group include an alkyl group of C ₁ ~ _10, its fluorinated derivatives, and F atom and the like Cl atoms of at least one selected from the group consisting of halogen atoms Examples thereof include the polycyclic aromatic group substituted with a group.

  In addition to this, for example, a homopolymer represented by the following general formula (3) or the following general formula (4) described in JP-A-8-511812, or a repeating unit represented by the following general formula ( Examples thereof include polyimides represented by 5). In addition, the polyimide of the following general formula (5) is a preferable form of the homopolymer of the following general formula (3).

In the general formulas (3) to (5), G and G ′ are, for example, a covalent bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, or a C (CX ₃ ) ₂ group. (Where X is a halogen atom), from the group consisting of CO, O, S, SO ₂ , Si (CH ₂ CH ₃ ) ₂ , and N (CH ₃ ) groups, Each represents an independently selected group, which may be the same or different.

In the general formula (3) and the general formula (5), L is a substituent, and d and e represent the number of substitutions. L is, for example, a halogen atom, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group, and in a plurality of cases, they are the same or different. Examples of the substituted phenyl group include substituted phenyl groups having at least one type of substituent selected from the group consisting of a halogen atom, a C _1-3 alkyl group, and a C _1-3 halogenated alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. d is an integer from 0 to 2, and e is an integer from 0 to 3.

  In the general formulas (3) to (5), Q is a substituent, and f represents the number of substitutions. Q is, for example, a group consisting of a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, a nitro group, a cyano group, a thioalkyl group, an alkoxy group, an aryl group, a substituted aryl group, an alkyl ester group, and a substituted alkyl ester group. And when Q is plural, they are the same or different. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the substituted alkyl group include a halogenated alkyl group. Examples of the substituted aryl group include a halogenated aryl group. f is an integer from 0 to 4, and g and h are integers from 0 to 3 and 1 to 3, respectively. Further, g and h are preferably larger than 1.

In the general formula (4), R ¹⁰ and R ¹¹ are groups independently selected from the group consisting of a hydrogen atom, a halogen atom, a phenyl group, a substituted phenyl group, an alkyl group, and a substituted alkyl group. Among these, R ¹⁰ and R ¹¹ are preferably each independently a halogenated alkyl group.

In the general formula (5), M ¹ and M ² are the same or different and are, for example, a halogen atom, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl. It is a group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the substituted phenyl group include substituted phenyl groups having at least one type of substituent selected from the group consisting of halogen atoms, C _1-3 alkyl groups, and C _1-3 halogenated alkyl groups. It is done.

  Specific examples of the polyimide represented by the general formula (3) include those represented by the following general formula (6).

  Furthermore, examples of the polyimide include a copolymer obtained by appropriately copolymerizing an acid dianhydride other than the skeleton (repeating unit) as described above and a diamine.

  Examples of the acid dianhydride include aromatic tetracarboxylic dianhydrides. Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, heterocyclic aromatic tetracarboxylic dianhydride, 2, And 2'-substituted biphenyltetracarboxylic dianhydride.

Examples of the pyromellitic dianhydride include pyromellitic dianhydride, 3,6-diphenylpyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyromellitic dianhydride, and 3,6-dibromo. Examples include pyromellitic dianhydride and 3,6-dichloropyromellitic dianhydride. Examples of the benzophenone tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2 , 2 ′, 3,3′-benzophenone tetracarboxylic dianhydride and the like. Examples of the naphthalenetetracarboxylic dianhydride include 2,3,6,7-naphthalene-tetracarboxylic dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride, 2,6 -Dichloro-naphthalene-1,4,5,8-tetracarboxylic dianhydride and the like. Examples of the heterocyclic aromatic tetracarboxylic dianhydride include thiophene-2,3,4,5-tetracarboxylic dianhydride and pyrazine-2,3,5,6-tetracarboxylic dianhydride. Pyridine-2,3,5,6-tetracarboxylic dianhydride and the like. Examples of the 2,2′-substituted biphenyltetracarboxylic dianhydride include 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-dichloro. -4,4 ', 5,5'-biphenyltetracarboxylic dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride, etc. can give.

  Other examples of the aromatic tetracarboxylic dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and bis (2,3-dicarboxyphenyl) methane dianhydride. Bis (2,5,6-trifluoro-3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3 3-hexafluoropropane dianhydride, 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4′-oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 4,4 ′ − [4,4′− Sopropylidene-di (p-phenyleneoxy)] bis (phthalic anhydride), N, N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl) And diethylsilane dianhydride.

  Among these, the aromatic tetracarboxylic dianhydride is preferably 2,2′-substituted biphenyltetracarboxylic dianhydride, more preferably 2,2′-bis (trihalomethyl) -4,4. ', 5,5'-biphenyltetracarboxylic dianhydride, more preferably 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride It is.

  Examples of the diamine include aromatic diamines, and specific examples include benzene diamine, diaminobenzophenone, naphthalene diamine, heterocyclic aromatic diamines, and other aromatic diamines.

  Examples of the benzenediamine include o-, m- and p-phenylenediamine, 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 1,4-diamino-2-phenylbenzene, and 1, Examples include diamines selected from the group consisting of benzenediamines such as 3-diamino-4-chlorobenzene. Examples of the diaminobenzophenone include 2,2'-diaminobenzophenone and 3,3'-diaminobenzophenone. Examples of the naphthalenediamine include 1,8-diaminonaphthalene and 1,5-diaminonaphthalene. Examples of the heterocyclic aromatic diamine include 2,6-diaminopyridine, 2,4-diaminopyridine, and 2,4-diamino-S-triazine.

  In addition to these, the aromatic diamine includes 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 4,4 ′-(9-fluorenylidene) -dianiline, 2,2′-bis ( Trifluoromethyl) -4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2′-dichloro-4,4′-diaminobiphenyl, 2,2 ′, 5 5′-tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) -1,1, 1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophen Xyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 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, and the like.

  As said polyetherketone, the polyaryletherketone represented by following General formula (7) described in Unexamined-Japanese-Patent No. 2001-49110 is mention | raise | lifted, for example.

  In the general formula (7), X represents a substituent, and q represents the number of substitutions. X is, for example, a halogen atom, a lower alkyl group, a halogenated alkyl group, a lower alkoxy group, or a halogenated alkoxy group, and when there are a plurality of X, they are the same or different.

Examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and among these, a fluorine atom is preferable. Examples of the lower alkyl group, for example, lower alkyl groups are preferable linear or branched C ₁ ~ _6, more preferably a straight-chain or branched alkyl group of C ₁ ~ _4. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group are preferable, and a methyl group and an ethyl group are particularly preferable. Examples of the halogenated alkyl group include halides of the lower alkyl group such as a trifluoromethyl group. Examples of the lower alkoxy group, for example, preferably a straight chain or branched chain alkoxy group of C ₁ ~ _6, more preferably a straight chain or branched chain alkoxy group of C ₁ ~ _4. Specifically, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, and a tert-butoxy group are more preferable, and a methoxy group and an ethoxy group are particularly preferable. . Examples of the halogenated alkoxy group include halides of the lower alkoxy group such as a trifluoromethoxy group.

  In the general formula (7), q is an integer from 0 to 4. In the general formula (7), it is preferable that q = 0 and that the carbonyl group bonded to both ends of the benzene ring and the oxygen atom of the ether are present in the para position.

In the general formula (7), R ¹ is a group represented by the following general formula (8), and m is an integer of 0 or 1.

  In the general formula (8), X ′ represents a substituent, and is the same as X in the general formula (7), for example. In the general formula (8), when there are a plurality of X's, they are the same or different. q ′ represents the number of substitutions of X ′ and is an integer from 0 to 4, preferably q ′ = 0. P is an integer of 0 or 1.

In the general formula (8), R ² represents a divalent aromatic group. Examples of the divalent aromatic group include an o-, m- or p-phenylene group, or naphthalene, biphenyl, anthracene, o-, m- or p-terphenyl, phenanthrene, dibenzofuran, biphenyl ether, or And divalent groups derived from biphenylsulfone. In these divalent aromatic groups, the hydrogen atom directly bonded to the aromatic group may be substituted with a halogen atom, a lower alkyl group or a lower alkoxy group. Among these, R ² is preferably an aromatic group selected from the group consisting of the following general formula (9) to the following general formula (15).

In the general formula (7), R ¹ is preferably a group represented by the following general formula (16). In the following general formula (16), R ² and p are as defined in the general formula (8). It is.

  Furthermore, in said general formula (7), n represents a polymerization degree, for example, is the range of 2-5000, Preferably, it is the range of 5-500. Further, the polymerization may be composed of repeating units having the same structure, or may be composed of repeating units having different structures. In the latter case, the polymerization mode of the repeating unit may be block polymerization or random polymerization.

  Furthermore, it is preferable that the end of the polyaryl ether ketone represented by the general formula (7) is fluorine on the p-tetrafluorobenzoylene group side and a hydrogen atom on the oxyalkylene group side. Can be represented, for example, by the following general formula (17). In the following general formula (17), n represents the same degree of polymerization as in the general formula (7).

  Specific examples of the polyaryl ether ketone represented by the general formula (7) include those represented by the following general formula (18) to the following general formula (21). From the following general formula (18) to the following In general formula (21), n represents the same degree of polymerization as in general formula (7).

  In addition to these, examples of the polyamide or polyester include polyamides and polyesters described in JP-T-10-508048, and their repeating units are represented by the following general formula (22), for example. Can be represented.

In the general formula (22), Y represents an O atom or an NH group. E is, for example, a covalent bond, a C ₂ alkylene group, a halogenated C ₂ alkylene group, a CH ₂ group, or a C (CX ₃ ) ₂ group (where X is a halogen atom or a hydrogen atom), It is at least one group selected from the group consisting of CO group, O atom, S atom, SO ₂ group, Si (R) ₂ group, and N (R) group, and may be the same or different. . In E, R is at least one of a C _1-3 alkyl group and a C _1-3 halogenated alkyl group, and is in a meta position or a para position with respect to a carbonyl functional group or a Y group.

  In the general formula (22), A and A ′ are substituents, and t and z each represent the number of substitutions. P is an integer from 0 to 3, q is an integer from 1 to 3, and r is an integer from 0 to 3.

The A is, for example, a hydrogen atom, a halogen atom, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, or an alkoxy group represented by OR (where R is as defined above). , Aryl groups, substituted aryl groups by halogenation, etc., C _1-9 alkoxycarbonyl groups, C _1-9 alkylcarbonyloxy groups, C _1-12 aryloxycarbonyl groups, C _1-12 arylcarbonyloxy groups and substituted derivatives thereof , A C _1-12 arylcarbamoyl group, and a C _1-12 arylcarbonylamino group and substituted derivatives thereof, and in the plurality of cases, they are the same or different. The A ′ is, for example, selected from the group consisting of a halogen atom, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, and a substituted phenyl group. . Examples of the substituent on the phenyl ring of the substituted phenyl group include a halogen atom, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, and combinations thereof. The t is an integer from 0 to 4, and the z is an integer from 0 to 3.

  Among the repeating units of polyamide or polyester represented by the general formula (22), those represented by the following general formula (23) are preferable.

  In the general formula (23), A, A ′ and Y are those defined in the general formula (22), and v is an integer of 0 to 3, preferably 0 to 2. x and y are each 0 or 1, but are not 0 at the same time.

  The method for producing the birefringent layer B is not particularly limited. For example, a solution in which a forming material is dissolved in a solvent is prepared, and this is applied to a substrate film having a smooth surface or a metal endless belt in a film form. The birefringent layer B may be formed by evaporating and removing the solvent.

  The material for forming the base film is not particularly limited, and a polymer having excellent transparency is preferable, and a thermoplastic resin is preferable because it is suitable for a stretching process and a shrinking process as described later. Specifically, for example, acetate resin such as triacetyl cellulose (TAC), polyester resin, polyethersulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, polynorbornene resin (for example, Trade name “ARTON” (manufactured by JSR Corporation), trade name “ZEONOR”, trade name “ZEONEX” (manufactured by Nippon Zeon Co., Ltd.), cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride Examples thereof include resins, polyvinylidene chloride resins, polyacrylic resins, and mixtures thereof. Moreover, a liquid crystalline polymer etc. can also be used. Further, for example, as described in JP-A-2001-343529 (WO 01/37007), a thermoplastic resin having a substituted imide group or an unsubstituted imide group in the side chain, and a substituted phenyl group in the side chain Alternatively, a mixture of a thermoplastic resin having an unsubstituted phenyl group and a nitrile group can also be used. Specific examples include a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. Among these forming materials, for example, a material capable of setting the birefringence index relatively lower when a transparent film is formed is preferable, and specifically, a substituted imide group or an unsubstituted imide group in the aforementioned side chain. And a mixture of a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a nitrile group in the side chain. Among the above resins, cellulose polymer films such as triacetyl cellulose (TAC), norbornene polymer films (trade name “ARTON” (manufactured by JSR Corporation), trade names “ZEONOR”, trade names “ZEONEX” ( A typical example is Zeon Corporation).

  Although the thickness of the said base film is about 10-1000 micrometers, for example, Preferably it is 20-500 micrometers, More preferably, it is 30-100 micrometers.

  The solvent of the solution to be applied is not particularly limited, and examples thereof include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; phenol, parachlorophenol. Phenols such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene and other aromatic hydrocarbons; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, N-methyl- Ketone solvents such as 2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol Alcohol solvents such as monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol and 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile systems such as acetonitrile and butyronitrile Solvents; ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran; carbon disulfide, ethyl cellosolve, butyl cellosolve, and the like. One type of these solvents may be used, or two or more types may be used in combination.

  For example, the coating solution may further contain various additives such as a stabilizer, a plasticizer, and metals as necessary.

  The coating solution may contain other different resins. Examples of the other resin include various general-purpose resins, engineering plastics, thermoplastic resins, and thermosetting resins.

  Examples of the general-purpose resin include polyethylene (PE), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), ABS resin, and AS resin. Examples of the engineering plastic include polyacetate (POM), polycarbonate (PC), polyamide (PA: nylon), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyethersulfone (PES), polyketone (PK), polyimide (PI), polycyclohexanedimethanol terephthalate (PCT), polyarylate (PAR), and liquid crystallinity. Examples thereof include a polymer (LCP). Examples of the thermosetting resin include an epoxy resin and a phenol novolac resin.

  Thus, when said other resin etc. are mix | blended with the said coating solution, the compounding quantity is 0-50 mass% with respect to the said polymer material, Preferably, it is 0-30 mass%. is there.

  Examples of the solution coating method include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. Moreover, in the case of coating, the superposition | polymerization method of a polymer layer is also employable as needed.

  After coating, the birefringent layer B is formed by evaporating and removing the solvent in the solution by, for example, natural drying, air drying, and heat drying (for example, 60 to 250 ° C.). The thickness of the birefringent layer is not particularly limited, but is, for example, 0.1 to 50 μm, preferably 0.5 to 30 μm, more preferably from the viewpoint of thinning the liquid crystal display device, viewing angle compensation, film homogeneity, and the like. Is in the range of 1-20 μm.

  The birefringent layer B preferably has a difference in refractive index (nx> ny) in the plane. If the birefringent layer B has a difference in refractive index in the plane and a difference in refractive index from the thickness direction, that is, nx> ny> nz (nx, ny and nz are the same as described above). This is because the obtained optical film is optically biaxial. Examples of a method for giving a difference in refractive index in the plane of the birefringent layer B include the following methods. First, a birefringence formed using a base film having in-plane shrinkage in one direction, applying the solution thereon and drying, and utilizing the in-plane shrinkage of the base film The layer can have an in-plane refractive index difference. In addition, by applying the solution on a substrate film stressed in one direction, or by blowing air from one direction to the coated solution, forming a birefringent layer, A difference in refractive index can also be provided. In addition, a difference in refractive index can be provided in the surface by coating the solution on an anisotropic base film to form a birefringent layer. Further, after forming a birefringent layer on the base film layer, the laminate can be stretched to give a difference in refractive index in the plane of the birefringent layer. Note that these methods may be combined.

  The birefringent layer B can also be used with the base film attached. In that case, the optical anisotropy of the base film is preferably Re <10 nm and Rth <20 nm, more preferably Re <8 nm and Rth <18 nm, Re <5 nm and Rth More preferably, it is <15 nm. Moreover, the said base film can also be utilized as a transparent protective layer of a polarizer. Re and Rth are defined in the same manner as in the above formula (6) and the above formula (7).

  Between the base film and the birefringent layer B, a layer that ensures adhesion can be provided as necessary. Examples of the forming material include polyethyleneimine, acrylic urethane, polyester urethane, and polycarbonate urethane resins.

  When the birefringent layer B is directly formed in the liquid crystal cell C, the coating solution is applied by spin coating or the like, and the solvent is removed by evaporation, as in the case of forming on the base film. Thus, the birefringent layer B can be formed. In addition, the birefringent layer B formed on the base film may be transferred to the liquid crystal cell C. The transfer is not particularly limited, and may be thermal transfer or transfer via an adhesive or an adhesive material. The surface on which the birefringent layer B is formed may be either the liquid crystal cell substrate on the backlight side or the viewing side, and may be inside or outside the substrate. In particular, when a high heat-resistant resin such as polyimide is used, it is suitable for providing a color filter even after the birefringent layer B is formed.

  The birefringent layer B may be formed on one surface of the base film layer, or may be formed on both surfaces. Further, the birefringent layer B may be a single layer or a multilayer structure of a single forming material or a plurality of forming materials.

  In addition, when the birefringent layer B is used together with a base film, it is preferable to further have at least one of an adhesive layer and a pressure-sensitive adhesive layer. This facilitates adhesion between the birefringent layer B and other members such as the polarizing plate, the birefringent layer A, and the liquid crystal cell C, and prevents the birefringent layer B from peeling off. Because.

  The material of the adhesive layer is not particularly limited. For example, a pressure sensitive adhesive made of a polymer such as acrylic, vinyl alcohol, silicone, polyester, polyurethane, or polyether, or a rubber pressure sensitive adhesive. Etc. can be used. Alternatively, these materials may contain fine particles to form a layer exhibiting light diffusibility. Among these, for example, a material excellent in hygroscopicity and heat resistance is preferable. With such a property, for example, when used in a liquid crystal display device, it can prevent foaming and peeling due to moisture absorption, deterioration of optical characteristics due to a difference in thermal expansion, warpage of the liquid crystal cell, etc., and high quality and durability. The display device is also excellent.

  The polarizing plate of the present invention is not particularly limited, and is, for example, a laminated polarizing plate including a polarizer and a transparent protective layer. A transparent protective layer may be laminated | stacked on both sides of a polarizer, and may be laminated | stacked only on either one surface. Moreover, when laminating | stacking on both surfaces, the same kind of transparent protective layer may be used, for example, and a different kind of transparent protective layer may be used.

  The polarizer is not particularly limited, and for example, by dying dichroic substances such as iodine and dichroic dyes on various films by using a conventionally known method, dyeing, crosslinking, stretching, and drying. The prepared one can be used. Among these, a film that transmits linearly polarized light when natural light is incident is preferable, and a film that is excellent in light transmittance and degree of polarization is preferable. Examples of the various films that adsorb the dichroic substance include high hydrophilicity such as polyvinyl alcohol (PVA) film, partially formalized PVA film, ethylene / vinyl acetate copolymer partially saponified film, and cellulose film. In addition to these, for example, polyene oriented films such as PVA dehydrated products and polyvinyl chloride dehydrochlorinated products can be used. Among these, PVA film is preferable. The thickness of the polarizer is usually in the range of 1 to 80 μm, but is not limited thereto.

  The transparent protective layer is not particularly limited, and a conventionally known transparent film can be used. For example, a layer having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like is preferable. Specific examples of the material for such a transparent protective layer include cellulose resins such as triacetyl cellulose, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and polynorbornene. Transparent resins such as polyethylene, polyolefin, acrylic, and acetate. Further, examples thereof include thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins. Among these, a TAC film whose surface is saponified with alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

  Examples of the transparent protective layer include polymer films described in JP-A No. 2001-343529 (WO01 / 37007). Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. For example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be used. The polymer film may be, for example, an extruded product of the resin composition.

  In the transparent protective layer, Re and Rth in the formula (6) and the formula (7) are preferably Re <10 nm and Rth <20 nm, respectively, more preferably, Re <8 nm and Rth <18 nm. More preferably, Re <5 nm and Rth <15 nm.

  The transparent protective layer may further have an optical compensation function. As described above, the transparent protective layer having an optical compensation function is intended to prevent coloring or increase the viewing angle for good viewing caused by a change in viewing angle based on a phase difference in a liquid crystal cell, for example. A well-known thing can be used. Specifically, for example, various stretched films obtained by uniaxially or biaxially stretching the transparent resin described above, alignment films such as liquid crystalline polymers, laminates in which alignment layers such as liquid crystal polymers are arranged on a transparent substrate, and the like. can give. Among these, the alignment film of the liquid crystalline polymer is preferable because it can achieve a wide viewing angle with good visual recognition, and in particular, the optical compensation layer composed of the tilted alignment layer of the discotic or nematic liquid crystal polymer is described above. An optically compensated retardation plate supported by a triacetyl cellulose film or the like is preferable. Examples of such an optical compensation retardation plate include commercially available products such as “WV film” manufactured by Fuji Photo Film Co., Ltd. The optical compensation retardation plate may be one in which optical properties such as retardation are controlled by laminating two or more film supports such as the retardation film and triacetyl cellulose film.

  The thickness of the transparent protective layer is not particularly limited, and can be appropriately determined according to, for example, the phase difference or the protective strength, but is usually 500 μm or less, preferably 5 to 300 μm, more preferably 5 to 150 μm. It is.

  The transparent protective layer is appropriately formed by a conventionally known method such as a method of applying the various transparent resins to the polarizer, or a method of laminating the transparent resin film or the optical compensation retardation plate on the polarizing film. It can be formed and a commercially available product can also be used.

  The transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, a treatment for preventing sticking or diffusion, antiglare, and the like. The hard coat treatment is for the purpose of preventing scratches on the surface of the polarizing plate, for example, a treatment for forming a cured film having excellent hardness and slipperiness composed of a curable resin on the surface of the transparent protective layer. It is. As the curable resin, for example, a silicone-based, urethane-based, acrylic-based, or epoxy-based ultraviolet curable resin can be used, and the treatment can be performed by a conventionally known method. The purpose of preventing sticking is to prevent adhesion between adjacent layers. The antireflection treatment is intended to prevent reflection of external light on the surface of the polarizing plate, and can be performed by forming a conventionally known antireflection layer or the like.

  The anti-glare treatment is intended to prevent visual interference of the light transmitted through the polarizing plate due to reflection of external light on the surface of the polarizing plate, for example, on the surface of the transparent protective layer by a conventionally known method, This can be done by forming a fine uneven structure. Examples of a method for forming such a concavo-convex structure include a roughening method by sandblasting or embossing, a method of forming the transparent protective layer by blending transparent fine particles in the transparent resin as described above, and the like. It is done.

  Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like. In addition, conductive inorganic fine particles, crosslinked or uncrosslinked Organic fine particles composed of polymer particles and the like can also be used. The average particle size of the transparent fine particles is not particularly limited, but is, for example, in the range of 0.5 to 20 μm. The blending ratio of the transparent fine particles is not particularly limited, but is generally preferably in the range of 2 to 70 parts by mass and more preferably in the range of 5 to 50 parts by mass per 100 parts by mass of the transparent resin as described above.

  The antiglare layer containing the transparent fine particles can be used as, for example, the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Furthermore, the anti-glare layer may also serve as a diffusion layer (visual compensation function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, anti-sticking layer, diffusion layer, anti-glare layer, etc. are laminated on the polarizing plate as an optical layer composed of, for example, a sheet provided with these layers, separately from the transparent protective layer. May be.

  The lamination method of a polarizer and a transparent protective layer is not particularly limited, and can be performed by a conventionally known method. In general, the same pressure-sensitive adhesives and adhesives as described above can be used, and the type thereof can be appropriately determined depending on the material of each component. Examples of the adhesive include polymer adhesives such as acrylic, vinyl alcohol, silicone, polyester, polyurethane, and polyether, and rubber adhesives. In addition, an adhesive composed of a water-soluble crosslinking agent of vinyl alcohol polymers such as glutaraldehyde, melamine, and oxalic acid can be used. The pressure-sensitive adhesives and adhesives as described above are hardly peeled off due to, for example, the influence of humidity and heat, and are excellent in light transmittance and degree of polarization. Specifically, when the polarizer is a PVA-based film, for example, a PVA-based adhesive is preferable from the viewpoint of the stability of the adhesion treatment. These adhesives and pressure-sensitive adhesives may be applied to the surface of the polarizer or the transparent protective layer as they are, for example, or a layer such as a tape or sheet composed of the adhesive or pressure-sensitive adhesive is disposed on the surface. May be. For example, when prepared as an aqueous solution, other additives and catalysts such as acids may be blended as necessary. In addition, when apply | coating the said adhesive agent, you may mix | blend another additive and catalysts, such as an acid, with the said adhesive agent aqueous solution, for example. The thickness of such an adhesive layer is not particularly limited, but is, for example, 1 nm to 500 nm, preferably 10 nm to 300 nm, and more preferably 20 nm to 100 nm. The method is not particularly limited, and for example, a conventionally known method using an adhesive such as an acrylic polymer or a vinyl alcohol polymer can be employed. In addition, an adhesive containing a water-soluble cross-linking agent of PVA polymer such as glutaraldehyde, melamine, oxalic acid and the like can be obtained because it can form a polarizing plate that is not easily peeled off even by humidity, heat, etc. preferable. These adhesives can be used by, for example, applying the aqueous solution to the surface of each component and drying. In the aqueous solution, for example, other additives and a catalyst such as an acid can be blended as necessary. Among these, as the adhesive, a PVA adhesive is preferable from the viewpoint of excellent adhesiveness with a PVA film.

  The polarizing plate of the present invention may further include another optical layer in addition to the transparent protective layer. Examples of the optical layer include conventionally known various optical layers used for forming a liquid crystal display device and the like such as a polarizing plate, a reflecting plate, a transflective plate, and a brightness enhancement film as shown below. One kind of these optical layers may be used, two or more kinds may be used in combination, one layer may be used, or two or more layers may be laminated. The laminated polarizing plate further including such an optical layer is preferably used as an integrated polarizing plate having an optical compensation function, for example, and is suitable for use in various image display devices such as being disposed on the surface of a liquid crystal cell. ing.

  Hereinafter, such an integrated polarizing plate will be described.

  First, an example of a reflective polarizing plate or a transflective polarizing plate will be described. The reflective polarizing plate further includes a reflective plate on the laminated polarizing plate of the present invention, and the transflective polarizing plate further includes a semi-transmissive reflective plate stacked on the laminated polarizing plate of the present invention.

  The reflective polarizing plate is usually disposed on the back side of a liquid crystal cell, and can be used for a liquid crystal display device (reflective liquid crystal display device) of a type that reflects incident light from the viewing side (display side). Such a reflective polarizing plate, for example, has an advantage that the liquid crystal display device can be thinned because the built-in light source such as a backlight can be omitted.

  The reflective polarizing plate can be produced by a conventionally known method such as a method of forming a reflective plate made of metal or the like on one surface of a polarizing plate exhibiting the elastic modulus. Specifically, for example, one surface (exposed surface) of the transparent protective layer in the polarizing plate is mat-treated as necessary, and a metal foil or a vapor deposition film made of a reflective metal such as aluminum is formed on the surface as a reflection plate. The reflective polarizing plate formed as follows.

  In addition, as described above, a reflective polarizing plate, etc., in which a reflecting plate reflecting the fine uneven structure is formed on a transparent protective layer containing fine particles in various transparent resins and having a fine uneven structure on the surface. It is done. A reflector having a fine concavo-convex structure on its surface has an advantage that, for example, incident light can be diffused by irregular reflection to prevent directivity and glaring appearance and to suppress uneven brightness. Such a reflector is, for example, directly on the uneven surface of the transparent protective layer by a conventionally known method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can form as a metal vapor deposition film.

  In addition, instead of the method of directly forming the reflecting plate on the transparent protective layer of the polarizing plate as described above, the reflecting plate is provided with a reflecting layer on an appropriate film such as a film used for the transparent protective layer. A sheet or the like may be used. Since the reflective layer in the reflective plate is usually composed of metal, for example, from the viewpoint of preventing the decrease in reflectance due to oxidation, and thus the long-term persistence of the initial reflectance, and the separate formation of a transparent protective layer, etc. The usage form is preferably a state in which the reflective surface of the reflective layer is covered with the film, a polarizing plate or the like.

  On the other hand, the transflective polarizing plate has a transflective reflective plate instead of the reflective plate in the reflective polarizing plate. Examples of the transflective reflector include a half mirror that reflects light through a reflective layer and transmits light.

  The transflective polarizing plate is usually provided on the back side of a liquid crystal cell. When a liquid crystal display device or the like is used in a relatively bright atmosphere, the incident light from the viewing side (display side) is reflected to display an image. In a relatively dark atmosphere, it can be used for a liquid crystal display device of a type that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate. That is, the transflective polarizing plate can save the energy of using a light source such as a backlight in a bright atmosphere, and can be used with the built-in light source in a relatively dark atmosphere. It is useful for the formation of etc.

  Next, an example of a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate will be described.

  The brightness enhancement film is not particularly limited, and for example, a linear multi-layer thin film of dielectric material or a multi-layer laminate of thin film films having different refractive index anisotropy transmits linearly polarized light having a predetermined polarization axis, Other light can be used that reflects light. As such a brightness enhancement film, for example, trade name “D-BEF” manufactured by 3M Co., Ltd. may be mentioned. Further, a cholesteric liquid crystal layer, in particular, an oriented film of a cholesteric liquid crystalline polymer, or a film in which the oriented liquid crystal layer is supported on a film substrate can be used. These reflect the right and left circularly polarized light and transmit the other light. For example, the product name “PCF350” manufactured by Nitto Denko Corporation, the product name “Transmax” manufactured by Merck, etc. can give.

  The various polarizing plates of the present invention as described above may be, for example, an optical member obtained by laminating the polarizing plate of the present invention and two or more optical layers.

  An optical member in which two or more optical layers are laminated in this manner can be formed by a method of sequentially laminating separately, for example, in the manufacturing process of a liquid crystal display device or the like. There are advantages such as excellent quality stability and assembly workability, and improvement in manufacturing efficiency of liquid crystal display devices and the like. For the lamination, various adhesive means such as an adhesive layer can be used as described above.

  The various polarizing plates as described above preferably have a pressure-sensitive adhesive layer or an adhesive layer because they can be easily laminated on other members such as a liquid crystal cell. It can be placed on one or both sides of the plate. The material of the adhesive layer is not particularly limited, and a conventionally known material such as an acrylic polymer can be used. In particular, foaming and peeling due to moisture absorption are prevented, optical characteristics are deteriorated due to a difference in thermal expansion, and a liquid crystal cell is warped. For example, it is preferable to form a pressure-sensitive adhesive layer having a low moisture absorption rate and excellent heat resistance, for example, from the viewpoints of prevention, and hence formability of a liquid crystal display device having high quality and excellent durability. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient. The pressure-sensitive adhesive layer is formed on the surface of the polarizing plate by, for example, adding a solution or a melt of various pressure-sensitive adhesive materials directly to a predetermined surface of the polarizing plate by a developing method such as casting or coating. In the same manner, a pressure-sensitive adhesive layer is formed on a separator, which will be described later, and transferred to a predetermined surface of the polarizing plate. Such a layer may be formed on any surface of the polarizing plate, for example, on the exposed surface of the retardation plate in the polarizing plate.

  Thus, when the surface of the pressure-sensitive adhesive layer or the like provided on the polarizing plate is exposed, it is preferable to cover the surface with a separator for the purpose of preventing contamination until the pressure-sensitive adhesive layer is put to practical use. This separator is provided with an appropriate film such as a film used for the transparent protective layer, if necessary, with one or more release coats using a release agent such as silicone, long chain alkyl, fluorine, molybdenum sulfide. It can be formed by a method or the like.

  For example, the pressure-sensitive adhesive layer may be a single layer or a laminate. As the laminate, for example, a laminate in which different compositions and different types of single-layer bodies are combined can be used. Moreover, when arrange | positioning on the both surfaces of the said polarizing plate, the same adhesive layer may respectively be sufficient, for example, a different composition and a different kind of adhesive layer may be sufficient.

  The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to, for example, the configuration of the polarizing plate, and is generally 1 to 500 μm.

  As the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer, for example, one that is excellent in optical transparency and exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties is preferable. Specific examples include pressure-sensitive adhesives prepared by appropriately using polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and synthetic rubbers as base polymers.

  Control of the adhesive property of the pressure-sensitive adhesive layer is, for example, the degree of cross-linking depending on the composition and molecular weight of the base polymer forming the pressure-sensitive adhesive layer, the crosslinking method, the content ratio of the crosslinkable functional group, the blending ratio of the crosslinking agent, It can be suitably carried out by a conventionally known method such as adjusting the molecular weight.

  Each layer such as the polarizing plate, various optical members, transparent protective layer, optical layer, and pressure-sensitive adhesive layer is, for example, a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound, etc. What gave the ultraviolet absorptivity by processing with a ultraviolet absorber suitably may be used.

Next, in the liquid crystal panel of the present invention, the birefringent layer A, the birefringent layer B, and the liquid crystal cell C are disposed between the two polarizing plates, and the constituent members are adhered with an adhesive or an adhesive. Can be produced. The pressure-sensitive adhesive or adhesive is not particularly limited, and for example, those described above can be used. The configuration of the liquid crystal panel is not particularly limited, and examples thereof include the following configurations (1) to (5). In the following configuration (1), the birefringent layer B is used. In the following configurations (4) and (5), the birefringent layer A also serves as a transparent protective layer, It constitutes a board. In the liquid crystal panel of the present invention, the viewing side and the backlight side are not particularly limited.
(1) Polarizing plate / birefringent layer A / liquid crystal cell C / birefringent layer B / polarizer (2) polarizing plate / birefringent layer A / liquid crystal cell C / birefringent layer B / polarizing plate (3) polarizing plate / Birefringent layer A / birefringent layer B / liquid crystal cell C / polarizing plate (4) polarizer / birefringent layer A / liquid crystal cell C / birefringent layer B / polarizing plate (5) polarizer / birefringent layer A / bipolar Refractive layer B / Liquid crystal cell C / Polarizing plate Next, structural examples of the liquid crystal panel of the present invention are shown in FIGS. In these drawings, the same parts are denoted by the same reference numerals.

  The configuration of the liquid crystal panel shown in FIG. 1 is the configuration example of (1). As shown in the figure, in this liquid crystal panel 1, a birefringent layer A12 and a polarizing plate 11 are laminated in this order on one surface (upper surface in the figure) of the liquid crystal cell C13, and the other liquid crystal cell C13 has the other side. The birefringent layer B14, the polarizer 111, and the transparent protective layer 112 are laminated in this order on the surface (the lower surface in the figure). The polarizing plate 11 is configured by laminating a transparent protective layer 112 on each of both surfaces of a polarizer 111. The birefringent layer B 14 is laminated on the polarizer 111 as a transparent protective layer, and forms the polarizing plate 16 together with the transparent protective layer 112.

  The configuration of the liquid crystal panel shown in FIG. 2 is the configuration example of (2). As shown in the figure, in this liquid crystal panel 2, a birefringent layer A12 and a polarizing plate 11 are laminated in this order on one surface (the upper surface in the figure) of the liquid crystal cell C13, and the other liquid crystal cell C13 has the other side. The birefringent layer B14 and the polarizing plate 11 are laminated in this order on the surface (the lower surface in the figure). The two polarizing plates 11 are configured by laminating a transparent protective layer 112 on each of both surfaces of a polarizer 111.

  The configuration of the liquid crystal panel shown in FIG. 3 is the configuration example of (3). As shown in the figure, in this liquid crystal panel 3, a birefringent layer B14, a birefringent layer A12, and a polarizing plate 11 are laminated in this order on one surface of the liquid crystal cell C13 (the upper surface in the figure), and the liquid crystal The polarizing plate 11 is laminated on the other surface (the lower surface in the figure) of the cell C13. The two polarizing plates 11 are configured by laminating a transparent protective layer 112 on each of both surfaces of a polarizer 111.

  The configuration of the liquid crystal panel shown in FIG. 4 is the configuration example of (4). As illustrated, in the liquid crystal panel 4, a birefringent layer A12, a polarizer 111, and a transparent protective layer 112 are laminated in this order on one surface (the upper surface in the figure) of the liquid crystal cell C13, and the liquid crystal The birefringent layer B14 and the polarizing plate 11 are laminated in this order on the other surface (the lower surface in the figure) of the cell C13. The polarizing plate 11 is configured by laminating a transparent protective layer 112 on each of both surfaces of a polarizer 111. The birefringent layer A12 is laminated on the polarizer 111 as a transparent protective layer, and constitutes the polarizing plate 16 together with the transparent protective layer 112.

  The configuration of the liquid crystal panel shown in FIG. 5 is the configuration example of (5). As shown in the figure, in this liquid crystal panel 5, the birefringent layer B14, the birefringent layer A12, the polarizer 111 and the transparent protective layer 112 are arranged in this order on one surface (the upper surface in the figure) of the liquid crystal cell C13. The polarizing plate 11 is laminated on the other surface (the lower surface in the drawing) of the liquid crystal cell C13. The polarizing plate 11 is configured by laminating a transparent protective layer 112 on each of both surfaces of a polarizer 111. The birefringent layer A12 is laminated on the polarizer 111 as a transparent protective layer, and constitutes the polarizing plate 16 together with the transparent protective layer 112.

  Next, examples of the present invention will be described together with comparative examples. In Examples and the like, various characteristics were measured and evaluated as follows. Here, in the following examples and the like, Δnxz is Δnxz = nx−nz, and the nx and the nz are the same as the definitions of the formula (1) and the formula (2).

(Chromatic dispersion measurement)
Using a trade name “Ellipsometer M-220” manufactured by JASCO Corporation, a phase difference was measured with respect to 40 ° incident light in a wavelength range of 380 to 800 nm.

(Re, Rth calculation method)
Using a trade name “Ellipsometer M-220” manufactured by JASCO Corporation, the sample was tilted from 0 to 40 ° at a wavelength of 550 nm, and the phase difference was measured to obtain Re and Rth.

(Viewing angle characteristics)
The viewing angle characteristics of the liquid crystal display device were measured using a trade name “EZ-Contrast” manufactured by ELDIM.

(Comparative Example 1)
50 parts by weight of an alternating copolymer consisting of isobutene and N-methylmaleimide (N-methylmaleimide content 50 mol%) and 50 parts by weight of an acrylonitrile-styrene copolymer having an acrylonitrile content of 28% by weight in methylene chloride Dissolution gave a solution with a solids concentration of 15% by weight. This solution was cast on a polyethylene terephthalate film (PET) laid on a glass plate, allowed to stand at room temperature for 60 minutes, then peeled off from the PET film, dried at 100 ° C. for 10 minutes, then 140 ° C. for 10 minutes, and further 160 Drying at 30 ° C. for 30 minutes gave a transparent film (I). In order to improve the mechanical strength, the film was biaxially stretched in two directions orthogonal to each other at 135 ° C. to obtain a transparent film X having a thickness of 50 μm. The transparent film X had d = 38 μm, Re = 1 nm, Rth = (nx−nz) d = 5 nm.

  A transparent film was bonded to both sides of a polarizer stretched by adsorbing iodine to a polyvinyl alcohol film to form a polarizing plate.

  A product name “ARTON” film manufactured by JSR Corporation was longitudinally uniaxially stretched at 175 ° C. to obtain a birefringent layer A (1) with Re = 142 nm and nx> ny = nz.

  2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane) and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl) as a mesoisobutyl ketone Dissolved and prepared at 20 wt%. It was coated on the transparent film X and dried at 120 ° C. for 5 minutes. A birefringent layer B (1) having d = 5.5 μm, Re = 1.1 nm, Rth = 205 nm, Δnxz = 0.037, and nx = ny> nz was obtained.

  Using the adhesive, the polarizing plate and the birefringent layer A (1) were bonded so that the absorption axis and the slow axis were orthogonal. The birefringent layer B (1) was bonded to the opposite side of the polarizer with the transparent film X provided on one side via an adhesive. Then, they were bonded to the upper and lower sides of the VA mode liquid crystal cell C via an adhesive so that the absorption axes of the polarizers were orthogonal to obtain a liquid crystal panel (I). This liquid crystal panel has the configuration shown in FIG. The VA mode liquid crystal cell C was used with the polarizing plate peeled off from a monitor (product number: LL-T1620) manufactured by Sharp Corporation.

Example 1
A product name “Pure Ace WR” manufactured by Teijin Limited was longitudinally uniaxially stretched at 230 ° C. to obtain a birefringent layer A (2) with Re = 145 nm and nx> ny = nz.

  Using the adhesive, the polarizing plate of Comparative Example 1 and the birefringent layer A (2) were bonded together so that the absorption axis and the slow axis were orthogonal to each other. The other used an elliptically polarizing plate having a birefringent layer B (1) as in Comparative Example 1. And it bonded together through the adhesive so that the absorption axis of the said 2 polarizer may orthogonally cross the liquid crystal cell C of the comparative example 1, and obtained liquid crystal panel (II). This liquid crystal panel has the configuration shown in FIG.

(Example 2)
A trade name “Pure Ace WR” manufactured by Teijin Limited was stretched at 230 ° C. to obtain a birefringent layer A (3) with Re = 110 nm, Rth = 160 nm, and nx>ny> nz.

  2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl) TFMB And was prepared at 20 wt%. It was coated on a PET film and dried at 170 ° C. for 5 minutes. A birefringent layer B (3) with d = 4.3 μm, Re = 0.8 nm, Rth = 172 nm, Δnxz = 0.04, and nx = ny> nz was obtained.

  The transparent protective layer of Comparative Example 1 is bonded to one side of the polarizer via an adhesive, and the birefringent layer A (3) is bonded to the opposite side so that the absorption axis and the slow axis are orthogonal to each other. Pasted through. Furthermore, the birefringent layer B (3) was transferred onto the birefringent layer A (3) via an adhesive to produce an elliptically polarizing plate. Moreover, the transparent protective layer of the comparative example 1 was bonded together on both sides of the said polarizer through the adhesive agent, and the said polarizing plate was obtained.

  An elliptically polarizing plate is bonded to one side of the same liquid crystal cell C as in Comparative Example 1 via an adhesive, and the two polarizing plates are bonded to the opposite side so that the absorption axes of the polarizers are orthogonal to each other. A liquid crystal panel (III) was obtained. This liquid crystal panel has the configuration shown in FIG.

(Example 3)
A product name “Pure Ace WR” manufactured by Teijin Limited was longitudinally uniaxially stretched at 230 ° C. to obtain a birefringent layer A (4) with Re = 97 nm and nx> ny = nz.

  2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane) and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl) to methyl isobutyl ketone Dissolved and prepared at 20 wt%. It was coated on a TAC film and dried at 130 ° C. for 5 minutes. Thereafter, only the TAC film was horizontally stretched at 150 ° C. to obtain a birefringent layer B (4) of d = 5.3 μm, Re = 25 nm, Rth = 235 nm, Δnxz = 0.044, and nx> ny> nz. Using the adhesive, the polarizing plate of Comparative Example 1 and the birefringent layer A (4) were bonded so that the absorption axis and the slow axis were perpendicular to each other, and another polarizing plate and the birefringent layer B (4) were bonded. Transfer was performed so that the absorption axis and the slow axis were orthogonal. And it bonded together through the adhesive so that the absorption axis of the said 2 polarizer might be orthogonally crossed on the liquid crystal cell C of the comparative example 1, and obtained liquid crystal panel (IV). This liquid crystal panel has the configuration shown in FIG.

(Comparative Example 2)
A TAC film manufactured by Fuji Film Co., Ltd. was bonded to both sides of the polarizer via an adhesive to produce a polarizing plate. The TAC film had Re = 0.7 nm and Rth = 59 nm.

  Polycarbonate was uniaxially stretched to obtain a birefringent layer A6 with Re = 105 nm and nx> ny = nz.

  2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane) and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl) to methyl isobutyl ketone Dissolved and prepared at 20 wt%. It was coated on the TAC film and dried at 130 ° C. for 5 minutes. A birefringent layer B (6) having d = 3.5 μm, Re = 0.5 nm, Rth = 145 nm, Δnxz = 0.041, and nx = ny> nz was obtained.

  Using the adhesive, the polarizing plate and the birefringent layer A (6) were bonded so that the absorption axis and the slow axis were orthogonal. In the other sheet, the birefringent layer B (6) together with the base material was bonded via an adhesive to the polarizer having a TAC film bonded to one side so that the TAC film was on the polarizer side. And it bonded together through the adhesive so that the absorption axis of the said polarizer might orthogonally cross the liquid crystal cell, and obtained liquid crystal panel (VI). This liquid crystal panel has the configuration shown in FIG.

(Comparative Example 3)
A product name “ARTON” film manufactured by JSR Corporation was longitudinally uniaxially stretched 1.2 times at 175 ° C. to obtain a birefringent layer A (7) of Re = 97 nm and nx> ny = nz. A liquid crystal panel (VII) was obtained in the same manner as in Comparative Example 2, except that the birefringent layer A (6) was changed to the birefringent layer A (7). This liquid crystal panel has the configuration shown in FIG.

  With respect to the liquid crystal panels of Examples 1 to 3 and Comparative Examples 1 to 3 thus obtained, the wavelength dispersion characteristics (α40) and viewing angle characteristics of the constituent members were examined. The results are shown in Table 1 and Table 2 below.

(table 1)
<Chromatic dispersion>
Liquid crystal cell: α40C = 1.079
α40A α40B
Comparative Example 1 1.006 1.109
Example 1 0.891 1.109
Example 2 0.900 1.105
Example 3 0.891 1.110
Comparative Example 2 1.100 1.103
Comparative Example 3 1.003 1.103
(Table 2)
<Viewing angle characteristics>
Chromatic dispersion Contrast Color shift in black state (x, y)
Comparative Example 1 α (B)> α (C)> α (A)> 1 ○ (0.327, 0.324) Δ Slightly red Example 1 α (B)> α (C)>1> α (A) ○ ( (0.315, 0.310)
Example 2 α (B)> α (C)>1> α (A) ○ (0.317,0.311) ◎
Example 3 α (B)> α (C)>1> α (A) ○ (0.318, 0.312) ◎
Comparative Example 2 α (B)> α (A)> α (C) ○ (0.385, 0.397) × Redish Comparative Example 3 α (B)> α (C)> α (A)> 1 ○ (0.351, 0.370) x Reddish

Omni-directional contrast: A value of 10 or more was marked as ◯.
Color shift: (x, y) at an azimuth angle of 45 ° / polar angle of 60 ° in a black display state was measured and visually observed. The closer to (x, y) = (0.31,0.31), the more neutral (CIE1931 color system).

  As can be seen from Table 1 and Table 2, the liquid crystal panel of the example having the conditions of the present invention was excellent in contrast and could effectively suppress color shift. In contrast, the liquid crystal panel of the comparative example was excellent in contrast, but could not suppress color shift.

  As described above, the liquid crystal panel of the present invention has a high contrast ratio over a wide range and can effectively suppress color shift. Therefore, the liquid crystal display device using the liquid crystal panel of the present invention has excellent display quality.

It is sectional drawing which shows the structure of an example of the liquid crystal panel of this invention. It is sectional drawing which shows the structure of the other example of the liquid crystal panel of this invention. It is sectional drawing which shows the structure of another example of the liquid crystal panel of this invention. It is sectional drawing which shows the structure of another example of the liquid crystal panel of this invention. It is sectional drawing which shows the structure of another example of the liquid crystal panel of this invention.

Explanation of symbols

1: Liquid crystal panel 11: Polarizing plate 111: Polarizer 112: Transparent protective layer 12: Birefringent layer A
13: Liquid crystal cell C
14: Birefringent layer B
16: Polarizing plate 2: Liquid crystal panel 3: Liquid crystal panel 4: Liquid crystal panel 5: Liquid crystal panel

Claims (7)

A liquid crystal panel including two polarizing plates, a birefringent layer A, a birefringent layer B, and a liquid crystal cell C,
The two polarizing plates are arranged so that their absorption axes are substantially orthogonal,
Between the two polarizing plates, the birefringent layer A, the birefringent layer B and the liquid crystal cell C are disposed,
The birefringent layer A has a refractive index anisotropy of the following formula (1):
The birefringent layer B has a refractive index anisotropy of the following formula (2), and the material for forming the birefringent layer B is 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane. ) And 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl),
The liquid crystal cell C is a liquid crystal cell in which the liquid crystal molecules are aligned substantially vertically with no voltage applied.
The wavelength dispersion characteristics (α40 (A)) of the birefringent layer A, the birefringent layer B (α40 (B)) and (α40 (C)) of the liquid crystal cell C are expressed by the following formulas (3) and ( A liquid crystal panel characterized by satisfying the condition 4).

Formula (1) nx> ny ≧ nz
Formula (2) nx ≧ ny> nz

In the formula (1) and the formula (2), nx, ny, and nz represent the refractive indexes in the X-axis direction, the Y-axis direction, and the Z-axis direction in the birefringent layers A and B, respectively. The X-axis direction is an axial direction that exhibits the maximum refractive index in each in-plane direction of the birefringent layers A and B, and the Y-axis direction is relative to the X-axis direction in each of the planes. The Z-axis direction indicates a thickness direction perpendicular to the X-axis direction and the Y-axis direction.

Formula (3) α40 (B)> α40 (C)> α40 (A)
Formula (4) 1> α40 (A)

In the formula (3) and the formula (4), as shown in the following formula (5), the wavelength dispersion characteristic α40 is based on the normal direction of the birefringent layer surface or the liquid crystal cell surface as a reference (0 °). It is the ratio of the retardation (Re) measured with incident light of each wavelength of 430 nm and 550 nm from a direction inclined by 40 °.

Formula (5) α40 = Re (430 nm) / Re (550 nm)
Re (430 nm): Retardation measured with incident light having a wavelength of 430 nm Re (550 nm): Retardation measured with incident light having a wavelength of 550 nm   The refractive index difference in the plane of the birefringent layer B (Δn = nx−ny, nx and ny are the same as those in the formula (2)) is in the range of 0.005 to 0.2. The liquid crystal panel described. The said polarizing plate contains a polarizer and the transparent protective layer laminated | stacked on this both sides, The transparent protective layer by the side of the said liquid crystal cell C satisfy | fills the conditions of following formula (6) and following formula (7). The liquid crystal panel according to 1 or 2 .

Formula (6) Re = (nx−ny) d <10 nm
Formula (7) Rth = (nx−nz) d <20 nm

In the formula (6) and the formula (7), nx, ny and nz are the same as the formula (1) and the formula (2). 4. The liquid crystal panel according to claim 1, wherein the birefringent layer B and the liquid crystal cell C are disposed adjacent to each other. The liquid crystal panel according to any one of claims 1 to 4 , wherein the birefringent layer A and the birefringent layer B are laminated in this order on one polarizing plate. The birefringent layer A is laminated on the polarizer of one polarizing plate, the birefringent layer A also serves as the transparent protective layer, and the slow axis of the birefringent layer A and the absorption axis of the polarizer The liquid crystal panel according to claim 5 , wherein the birefringent layer B is laminated on the birefringent layer A. A liquid crystal display device comprising the liquid crystal panel according to claim 1 .

Images