JP2009251326A - Liquid crystal panel and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel having an excellent screen contrast, and less color shift, and to provide a liquid crystal display. <P>SOLUTION: The liquid crystal panel includes: a liquid crystal cell; a first polarizer disposed on one side of the liquid crystal cell; a first optical compensation layer of which the indicatrix shows a relation nz>nx>ny, a second optical compensation layer of which the indicatrix shows a relation nx>ny=nz and the in-plane retardation Re<SB>2</SB>is 80-200 nm, and a third optical compensation layer of which the indicatrix shows a relation nx=ny>nz, each disposed between the liquid crystal cell and the first polarizer sequentially from the first polarizer side; a second polarizer disposed on the other side of the liquid crystal cell; a fourth optical compensation layer of which the indicatrix shows a relation nx>ny>nz, a fifth optical compensation layer of which the indicatrix shows a relation nx>ny=nz and the in-plane retardation Re<SB>5</SB>is 80-200 nm, and a sixth optical compensation layer of which the indicatrix shows a relation nx=ny>nz, each disposed between the liquid crystal cell and the second polarizer, sequentially from the second polarizer side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device. More specifically, the present invention relates to a liquid crystal cell and a liquid crystal panel and a liquid crystal display device having at least three optical compensation layers on each side of the liquid crystal cell.

  In general, various optical films in which a polarizing film and an optical compensation layer are combined are used in image display devices (for example, liquid crystal display devices) in order to perform optical compensation.

  A circularly polarizing plate which is a kind of the optical film can be usually produced by combining a polarizing film and a λ / 4 plate. However, the λ / 4 plate generally exhibits a characteristic that the phase difference value increases as the wavelength becomes shorter, that is, a so-called “positive wavelength dispersion characteristic”, and generally has a large wavelength dispersion characteristic. Therefore, there is a problem that desired optical characteristics (for example, a function as a λ / 4 plate) cannot be exhibited over a wide wavelength range. In order to avoid such problems, in recent years, as a phase difference plate exhibiting a wavelength dispersion characteristic in which a retardation value increases as the wavelength becomes longer, that is, a so-called “reverse dispersion characteristic”, for example, a modified cellulose film and Modified polycarbonate films have been proposed. However, these films have a problem in terms of cost.

Therefore, at present, for a λ / 4 plate having positive wavelength dispersion characteristics, for example, by combining a retardation plate whose retardation value increases as it becomes longer wavelength side, or a λ / 2 plate, the above-mentioned λ / 4 plate is used. A method of correcting the wavelength dispersion characteristics of the plate is employed (see, for example, Patent Document 1). However, these techniques are insufficient in both improving the screen contrast and reducing the color shift.
Japanese Patent No. 3174367

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a liquid crystal panel and a liquid crystal display device having excellent screen contrast and small color shift.

The liquid crystal panel of the present invention includes a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, and the first polarizer side between the liquid crystal cell and the first polarizer. Are arranged in order from the first optical compensation layer in which the refractive index ellipsoid shows a relationship of nz>nx> ny, the refractive index ellipsoid shows the relationship of nx> ny = nz, and the in-plane retardation Re ₂ is 80. A second optical compensation layer of ˜200 nm, a third optical compensation layer whose refractive index ellipsoid shows a relationship of nx = ny> nz, and a second polarization arranged on the other side of the liquid crystal cell A fourth optical compensation layer in which a refractive index ellipsoid is arranged in order from the second polarizer side between the polarizer and the liquid crystal cell and the second polarizer and has a relationship of nx>ny> nz , the refractive index ellipsoid showed a relationship of nx> ny = nz, the fifth optical compensation layer plane retardation Re ₅ is 80 to 200 nm, And a refractive index ellipsoid and a sixth optical compensation layer showing the relationship of nx = ny> nz.

  In a preferred embodiment, the first polarizer is arranged on the viewing side.

  In a preferred embodiment, the first polarizer is disposed on the backlight side.

  In a preferred embodiment, the absorption axis of the first polarizer and the slow axis of the first optical compensation layer are arranged in parallel or orthogonal to each other.

  In a preferred embodiment, the absorption axis of the second polarizer and the slow axis of the fourth optical compensation layer are arranged in parallel or orthogonal to each other.

  In a preferred embodiment, the Nz coefficient of the first optical compensation layer is −1.0 or less.

  In a preferred embodiment, the liquid crystal cell is a VA mode.

  According to another aspect of the present invention, a liquid crystal display device is provided. The liquid crystal display device includes the liquid crystal panel.

  According to the present invention, the liquid crystal panel includes at least three predetermined optical compensation layers on each side of the liquid crystal cell, thereby improving the screen contrast and reducing the color shift.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of terms and symbols)
The definitions of terms and symbols in this specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
The in-plane retardation (Re) means an in-plane retardation value of a layer (film) at 23 ° C., and a wavelength of 590 nm unless otherwise specified. Re is obtained by Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film). In this specification, when Re (550) is indicated, it means an in-plane retardation of a layer (film) at a wavelength of 550 nm. Further, the subscript “1” attached to the terms and symbols described in the present specification represents the first optical compensation layer, the subscript “2” represents the second optical compensation layer, and the subscript. "3" in the figure represents the third optical compensation layer. For example, showing an in-plane retardation of the first optical compensation layer and the Re _1.
(3) Thickness direction retardation (Rth)
Thickness direction retardation (Rth) is a retardation value in the thickness direction of a layer (film) at a wavelength of 590 nm unless otherwise specified. Rth is determined by Rth = (nx−nz) × d, where d (nm) is the thickness of the layer (film). In addition, in this specification, when Rth (550) is shown, it means the retardation in the thickness direction of the layer (film) at a wavelength of 550 nm. In the present specification, for example, the thickness direction retardation of the first optical compensation layer is indicated as Rth ₁ .
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) λ / 4 plate The λ / 4 plate is an electro-optic birefringent plate that serves to rotate the polarization plane of the light beam, and ¼ wavelength between linearly polarized light that vibrates in directions perpendicular to each other. It has the function which produces the optical path difference of.

A. 1 is a schematic sectional view of a liquid crystal panel according to a preferred embodiment of the present invention. As illustrated, the liquid crystal panel 100 includes a liquid crystal cell 20, a first polarizer 11 disposed on one side of the liquid crystal cell 20, and a first between the liquid crystal cell 20 and the first polarizer 11. The first optical compensation layer 12, the second optical compensation layer 13, the third optical compensation layer 14, and the first optical compensation layer 12 arranged on the other side of the liquid crystal cell 20 are arranged in this order from the polarizer 11 side. The fourth optical compensation layer 15 and the fifth optical compensation, which are arranged in order from the second polarizer 11 ′ side between the two polarizers 11 ′ and the liquid crystal cell 20 and the second polarizer 11 ′. A layer 16 and a sixth optical compensation layer 17. Although not shown, a first protective layer is provided between the first polarizer 11 and the first optical compensation layer 12 as necessary, and the first optical compensation layer 12 of the first polarizer 11 is provided. A second protective layer is provided on the opposite side. Although not shown, a third protective layer is provided between the second polarizer 11 ′ and the fourth optical compensation layer 15 as necessary, and the fourth polarizer of the second polarizer 11 ′. A fourth protective layer is provided on the opposite side of the optical compensation layer 15. When the third protective layer is not provided, the fourth optical compensation layer 15 can also function as a protective layer for the second polarizer 11 ′. The fourth optical compensation layer 15 functions as a protective layer, which can contribute to thinning of the liquid crystal panel. For convenience, the first polarizer 11, the first optical compensation layer 12, the second optical compensation layer 13, and the third optical compensation layer 14 are collectively referred to as a first laminated optical film 10. The two polarizers 11 ′, the fourth optical compensation layer 15, the fifth optical compensation layer 16, and the sixth optical compensation layer 17 may be collectively referred to as a second laminated optical film 30.

  The liquid crystal panel 100 may further include other optical elements as necessary. As such another optical element, any appropriate optical element can be adopted depending on the purpose and the type of the liquid crystal panel. Specific examples include a liquid crystal film, a light scattering film, a diffraction film, and another optical compensation layer (retardation film).

  In the liquid crystal panel 100, the first polarizer 11 and the second polarizer 11 'are typically arranged so that their absorption axes are orthogonal to each other. In the present specification, the term “orthogonal” includes a case of being substantially orthogonal. Here, “substantially orthogonal” includes the case of 90 ° ± 3.0 °, preferably 90 ° ± 1.0 °, more preferably 90 ° ± 0.5 °.

  The first optical compensation layer 12 has a refractive index ellipsoid of nz> nx> ny. The first optical compensation layer 12 is arranged so that its slow axis forms any appropriate angle with respect to the absorption axis of the first polarizer 11 according to the purpose, the configuration of the liquid crystal panel, and the like. Preferably, the first polarizer 11 and the first optical compensation layer 12 are arranged so that the absorption axis and the slow axis thereof are parallel or orthogonal to each other. By disposing the first polarizer 11 and the first optical compensation layer 12 in such a positional relationship, a liquid crystal panel with improved screen contrast and reduced color shift can be obtained. In the present specification, the term “parallel” includes the case of being substantially parallel. Here, “substantially parallel” includes the case of 0 ° ± 3.0 °, preferably 0 ° ± 1.0 °, more preferably 0 ° ± 0.5 °.

  The second optical compensation layer 13 has a refractive index ellipsoid of nx> ny = nz. The second optical compensation layer 13 is arranged so that its slow axis forms any appropriate angle with respect to the absorption axis of the first polarizer 11 according to the purpose, the configuration of the liquid crystal panel, and the like. Specifically, the second optical compensation layer 13 has a slow axis of preferably 37 ° to 52 °, more preferably 40 ° to 50 °, and still more preferably with respect to the absorption axis of the first polarizer 11. Can be arranged at an angle of 42 ° to 48 °, particularly preferably about 45 °. By arranging the first polarizer 11 and the second optical compensation layer 13 in such a positional relationship, a liquid crystal panel with improved screen contrast and reduced color shift can be obtained.

  The fourth optical compensation layer 15 has a refractive index ellipsoid of nx> ny> nz. The fourth optical compensation layer 15 is arranged so that its slow axis forms any appropriate angle with respect to the absorption axis of the second polarizer 11 ′ according to the purpose, the configuration of the liquid crystal panel, and the like. . Preferably, the second polarizer 11 ′ and the fourth optical compensation layer 15 are arranged so that the absorption axis and the slow axis thereof are parallel or orthogonal to each other. By disposing the second polarizer 11 ′ and the fourth optical compensation layer 15 in such a positional relationship, a liquid crystal panel with improved screen contrast and reduced color shift can be obtained.

  The fifth optical compensation layer 16 has a refractive index ellipsoid of nx> ny = nz. The fifth optical compensation layer 16 is arranged so that its slow axis forms any appropriate angle with respect to the absorption axis of the second polarizer 11 ′ according to the purpose, the configuration of the liquid crystal panel, and the like. . Specifically, the fifth optical compensation layer 16 has a slow axis of preferably 37 ° to 52 °, more preferably 40 ° to 50 ° with respect to the absorption axis of the second polarizer 11 ′. It may be arranged so as to form an angle of preferably 42 ° to 48 °, particularly preferably about 45 °. By disposing the second polarizer 11 'and the fifth optical compensation layer 16 in such a positional relationship, a liquid crystal panel with improved screen contrast and reduced color shift can be obtained.

  The liquid crystal panel of the present invention may be arranged so that the first polarizer 11 is on the viewing side, or may be arranged so that the first polarizer 11 is on the backlight side.

B. Liquid Crystal Cell The liquid crystal cell 20 includes a pair of substrates 21 and 21 ′ and a liquid crystal layer 22 as a display medium sandwiched between the substrates 21 and 21 ′. One substrate (color filter substrate) 21 is provided with a color filter and a black matrix (both not shown). On the other substrate (active matrix substrate) 21 ′, a switching element (typically TFT) (not shown) for controlling the electro-optical characteristics of the liquid crystal and a scanning line (not shown) for supplying a gate signal to this switching element. ) And a signal line (not shown) for supplying a source signal, and a pixel electrode (not shown). The color filter may be provided on the active matrix substrate 21 ′ side. A distance (cell gap) between the substrates 21 and 21 'is controlled by a spacer (not shown). For example, an alignment film (not shown) made of polyimide is provided on the side of the substrates 21, 21 ′ in contact with the liquid crystal layer 22.

  Any appropriate drive mode can be adopted as the drive mode of the liquid crystal cell 20. The VA mode is preferable. FIG. 2 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in FIG. 2A, when no voltage is applied, the liquid crystal molecules are aligned perpendicular to the surfaces of the substrates 21 and 21 '. Such vertical alignment can be realized by arranging a nematic liquid crystal having negative dielectric anisotropy between substrates on which a vertical alignment film (not shown) is formed. When light is incident from the surface of one substrate 21 in such a state, the linearly polarized light that has passed through the first polarizer 11 and entered the liquid crystal layer 22 is the major axis of the vertically aligned liquid crystal molecules. Proceed along the direction of Since birefringence does not occur in the major axis direction of the liquid crystal molecules, the incident light travels without changing the polarization direction and is absorbed by the second polarizer 11 ′ having a polarization axis orthogonal to the first polarizer 11. This provides a dark display when no voltage is applied (normally black mode). As shown in FIG. 2B, when a voltage is applied between the electrodes, the major axis of the liquid crystal molecules is aligned parallel to the substrate surface. The liquid crystal molecules in this state exhibit birefringence with respect to linearly polarized light that has passed through the first polarizer 11 and entered the liquid crystal layer 22, and the polarization state of the incident light changes according to the inclination of the liquid crystal molecules. To do. Light that passes through the liquid crystal layer when a predetermined maximum voltage is applied becomes, for example, linearly polarized light whose polarization direction is rotated by 90 °, and therefore, a bright display can be obtained through the second polarizer 11 ′. . When the voltage is not applied again, the display can be returned to the dark state by the orientation regulating force. Also, gradation display is possible by changing the applied voltage to control the tilt of the liquid crystal molecules to change the transmitted light intensity from the second polarizer 11 '.

C. Polarizer Any appropriate polarizer may be employed as the first and second polarizers depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 1 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced by, for example, dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

D. First Optical Compensation Layer In the first optical compensation layer, the refractive index ellipsoid shows a relationship of nz>nx> ny. The in-plane retardation Re ₁ of the first optical compensation layer preferably satisfies the relationship of 10 nm ≦ Re ₁ <70 nm. Re ₁ is more preferably 10 to 60 nm, still more preferably 10 to 50 nm, and particularly preferably 10 to 40 nm. The thickness direction retardation Rth ₁ of the first optical compensation layer is preferably −200 to −50 nm, more preferably −150 to −55 nm, and particularly preferably −100 to −60 nm. The Nz coefficient (Rth ₁ / Re ₁ ) of the first optical compensation layer is preferably −1.0 or less, more preferably −20 to −1.0, and particularly preferably −10 to −1.0. is there. By providing the first optical compensation layer having such optical characteristics, the absorption axis of the polarizer can be suitably compensated, and the screen contrast of the liquid crystal panel when viewed from an oblique direction can be improved. Further, the color shift can be reduced.

  The first optical compensation layer can be of any suitable configuration. Specifically, the retardation film alone may be used, or a laminate of two or more retardation films that are the same or different may be used. In the case of a laminate, the first optical compensation layer can include an adhesive layer and an adhesive layer for attaching two or more retardation films. Preferably, the first optical compensation layer is a single retardation film. By adopting such a configuration, it is possible to reduce the shift and unevenness of the retardation value due to the contraction stress of the polarizer and the heat of the light source, and to contribute to the thinning of the obtained liquid crystal panel.

  The optical characteristics of the retardation film can be set to any appropriate value depending on the configuration of the first optical compensation layer. For example, when the first optical compensation layer is a retardation film alone, it is preferable that the optical characteristics of the retardation film be equal to the optical characteristics of the first optical compensation layer. Therefore, it is preferable that the retardation values of the pressure-sensitive adhesive layer, the adhesive layer, and the like used when laminating the retardation film on a polarizer or other optical compensation layer are as small as possible.

  The total thickness of the first optical compensation layer is preferably 10 to 500 μm, more preferably 20 to 400 μm, and particularly preferably 30 to 300 μm. When the thickness of the first optical compensation layer is within such a range, the handling property at the time of manufacture is excellent, and the optical uniformity of the obtained liquid crystal display device (liquid crystal panel) can be enhanced.

  As the retardation film, a film which is excellent in transparency, mechanical strength, thermal stability, moisture shielding property and the like and hardly causes optical unevenness due to strain is preferably used. As the retardation film, a stretched polymer film mainly composed of a thermoplastic resin is preferably used. As the thermoplastic resin, a polymer exhibiting negative birefringence is preferably used. By using a polymer exhibiting negative birefringence, a retardation film having a refractive index ellipsoid of nz> nx> ny can be easily obtained. Here, “showing negative birefringence” means that when the polymer is oriented by stretching or the like, the refractive index in the stretching direction becomes relatively small. In other words, the refractive index in the direction orthogonal to the stretching direction is increased. Examples of the polymer exhibiting negative birefringence include a polymer in which a chemical bond or a functional group having a large polarization anisotropy such as an aromatic ring or a carbonyl group is introduced into a side chain. Specific examples include acrylic resins, styrene resins, maleimide resins, and the like.

  The acrylic resin can be obtained, for example, by addition polymerization of an acrylate monomer. Examples of the acrylic resin include polymethyl methacrylate (PMMA), polybutyl methacrylate, polycyclohexyl methacrylate, and the like.

  The styrene resin can be obtained, for example, by addition polymerization of a styrene monomer. Examples of the styrenic monomer include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, p-aminostyrene, p-carboxystyrene, p-phenylstyrene, 2,5-dichlorostyrene, pt-butylstyrene, etc. are mentioned.

  The maleimide resin can be obtained, for example, by addition polymerization of a maleimide monomer. Examples of maleimide monomers include N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (2-ethylphenyl) maleimide, and N- (2-propylphenyl). ) Maleimide, N- (2-isopropylphenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-dipropylphenyl) maleimide, N- (2,6-diisopropylphenyl) maleimide, N- (2-methyl-6-ethylphenyl) maleimide, N- (2-chlorophenyl) maleimide, N- (2,6-dichlorophenyl) maleimide, N- (2-bromophenyl) maleimide, N- (2,6 -Dibromophenyl) maleimide, N- (2-biphenyl) maleimide, N- 2-cyanophenyl) maleimide, and the like. The maleimide monomer can be obtained from, for example, Tokyo Chemical Industry Co., Ltd.

  In the above addition polymerization, the birefringence characteristics of the obtained resin can be controlled by, for example, substituting the side chain, allowing the maleimidation or grafting reaction after the polymerization.

  The polymer exhibiting negative birefringence may be copolymerized with other monomers. When other monomers are copolymerized, brittleness, molding processability, and heat resistance can be improved. Examples of the other monomer include olefins such as ethylene, propylene, 1-butene, 1,3-butadiene, 2-methyl-1-butene, 2-methyl-1-pentene, and 1-hexene; acrylonitrile; acrylic acid (Meth) acrylates such as methyl and methyl methacrylate; maleic anhydride; vinyl esters such as vinyl acetate and the like.

  When the polymer exhibiting negative birefringence is a copolymer of the styrene monomer and the other monomer, the blending ratio of the styrene monomer is preferably 50 to 80 mol%. When the polymer exhibiting negative birefringence is a copolymer of the maleimide monomer and the other monomer, the blending ratio of the maleimide monomer is preferably 2 to 50 mol%. By blending in such a range, a polymer film excellent in toughness and molding processability can be obtained.

  As the polymer exhibiting negative birefringence, a styrene-maleic anhydride copolymer, a styrene-acrylonitrile copolymer, a styrene- (meth) acrylate copolymer, a styrene-maleimide copolymer, a vinyl ester- A maleimide copolymer, an olefin-maleimide copolymer, or the like is used. These can be used alone or in combination of two or more. These polymers exhibit high negative birefringence and can be excellent in heat resistance. These polymers can be obtained from Nova Chemical Japan, Arakawa Chemical Industries, Ltd., etc., for example.

As the polymer exhibiting negative birefringence, a polymer having a repeating unit represented by the following general formula (I) is also preferably used. Such a polymer can further exhibit high negative birefringence and can be excellent in heat resistance and mechanical strength. Such a polymer can be obtained, for example, by using N-phenyl-substituted maleimide having a phenyl group having a substituent at least in the ortho position as the N-substituent of the starting maleimide monomer.

In the general formula (I), R _{1 to} R ₅ are each independently hydrogen, a halogen atom, a carboxylic acid, a carboxylic acid ester, a hydroxyl group, a nitro group, or a linear or branched group having 1 to 8 carbon atoms. Represents an alkyl group or an alkoxy group (provided that R ₁ and R ₅ are not hydrogen atoms at the same time), and R ₆ and R ₇ represent hydrogen or a linear or branched alkyl group or alkoxy group having 1 to 8 carbon atoms. N represents an integer of 2 or more.

  The polymer exhibiting negative birefringence is not limited to the above, and for example, a cyclic olefin copolymer as disclosed in JP-A-2005-350544 and the like can also be used. Furthermore, a composition containing a polymer and inorganic fine particles as disclosed in JP-A-2005-156862, JP-A-2005-227427, and the like can also be suitably used. Moreover, as a polymer which shows negative birefringence, 1 type may be used independently and 2 or more types may be mixed and used. Further, they can be used after being modified by copolymerization, branching, crosslinking, molecular end modification (or sealing), stereoregular modification, or the like.

  The polymer film may further contain any appropriate additive as required. Specific examples of additives include plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, thickeners, etc. Is mentioned. The kind and content of the additive can be appropriately set according to the purpose. The content of the additive is typically about 10 parts by weight with respect to 100 parts by weight of the total solid content of the polymer film. If the content of the additive is excessively large, the transparency of the polymer film may be impaired, or the additive may ooze from the surface of the polymer film.

  Any appropriate forming method can be adopted as a method for forming the polymer film. Examples thereof include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, solvent casting, and the like. Among these, the extrusion molding method and the solvent casting method are preferably used. This is because a retardation film having high smoothness and good optical uniformity can be obtained. Specifically, in the extrusion molding method, the resin composition containing the thermoplastic resin, plasticizer, additive and the like is heated and melted, and this is extruded into a thin film shape on the surface of the casting roll by a T die or the like. It is a method of forming a film by cooling. In the solvent casting method, a concentrated solution (dope) in which the resin composition is dissolved in a solvent is defoamed and cast uniformly on a surface of a metallic endless belt or rotating drum, or a plastic substrate in the form of a thin film. The film is formed by evaporating the solvent. The molding conditions can be appropriately set according to the composition and type of the resin used, the molding method, and the like.

  The retardation film (stretched film) can be obtained by stretching the polymer film under any appropriate stretching condition. Specific examples of the stretching method include a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and transverse sequential biaxial stretching method, and a longitudinal and transverse simultaneous biaxial stretching method. Preferably, a transverse uniaxial stretching method, a longitudinal and transverse sequential biaxial stretching method, and a longitudinal and transverse simultaneous biaxial stretching method are used. This is because a biaxial retardation film can be suitably obtained. In the polymer exhibiting negative birefringence, since the refractive index in the stretching direction is relatively small as described above, the transverse uniaxial stretching method has a slow axis in the transport direction of the polymer film ( The refractive index in the transport direction is nx). In the case of the longitudinal / horizontal sequential biaxial stretching method and the longitudinal / horizontal simultaneous biaxial stretching method, both the conveying direction and the width direction can be slow axes depending on the ratio of the longitudinal and lateral stretching ratios. Specifically, when the stretching ratio in the longitudinal (conveyance) direction is relatively large, the transverse (width) direction becomes the slow axis, and when the stretching ratio in the transverse (width) direction is relatively large, the longitudinal (conveyance) The direction is the slow axis.

  Any appropriate stretching apparatus can be used as the stretching apparatus used for the stretching. Specific examples include a roll stretching machine, a tenter stretching machine, a pantograph type or a linear motor type biaxial stretching machine. When stretching while heating, the temperature may be continuously changed or may be changed stepwise. Further, the stretching process may be divided into two or more times.

  The stretching temperature (temperature in the stretching oven when stretching the polymer film) is preferably near the glass transition temperature (Tg) of the polymer film. Specifically, it is preferably (Tg-10) ° C to (Tg + 30) ° C, more preferably Tg to (Tg + 25) ° C, and particularly preferably (Tg + 5) ° C to (Tg + 20) ° C. If the stretching temperature is too low, the retardation value and the direction of the slow axis may be non-uniform, or the polymer film may be crystallized (white turbidity). On the other hand, if the stretching temperature is excessively high, the polymer film may be melted or the retardation may be insufficiently developed. The stretching temperature is typically 110 to 200 ° C. In addition, a glass transition temperature can be calculated | required by DSC method according to JISK7121-1987.

  Arbitrary appropriate methods may be employ | adopted for the method of controlling the temperature in the said drawing oven. Examples thereof include a method using an air circulation type constant temperature oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, a roll heated for temperature adjustment, a heat pipe roll, or a metal belt.

  The draw ratio when stretching the polymer film is set to any appropriate value depending on the composition of the polymer film, the type of volatile component, the residual amount of volatile component, the desired retardation value, etc. Can be done. Preferably it is 1.05-5.00 times. Moreover, the feeding speed at the time of stretching is preferably 0.5 to 20 m / min from the viewpoint of mechanical accuracy and stability of the stretching apparatus.

  As mentioned above, although the method of obtaining a retardation film using the polymer which shows negative birefringence has been described, the retardation film can also be obtained using the polymer which shows positive birefringence. Examples of a method for obtaining a retardation film using a polymer exhibiting positive birefringence are disclosed in Japanese Patent Application Laid-Open Nos. 2000-23310, 2000-206328, 2002-207123, and the like. Such a stretching method that increases the refractive index in the thickness direction can be used. Specifically, the heat-shrinkable film is adhered to one or both sides of a film containing a polymer exhibiting positive birefringence, and a heat treatment is performed. The film can be shrunk under the action of the shrinkage force of the heat-shrinkable film by heat treatment to shrink the length direction and width direction of the film, thereby increasing the refractive index in the thickness direction, nz> nx A retardation film having a refractive index ellipsoid of> ny can be obtained.

  Thus, the retardation film used for the first optical compensation layer can be produced using any polymer showing positive and negative birefringence. In general, when using a polymer exhibiting positive birefringence, there are advantages in that there are many types of polymers that can be selected. When using a polymer exhibiting negative birefringence, a polymer exhibiting positive birefringence is provided. Compared with the case of using the film, the film has an advantage in that a retardation film excellent in uniformity in the slow axis direction can be easily obtained due to the stretching method.

  In addition to the above-described film, a commercially available optical film can be used as it is as the retardation film used for the first optical compensation layer. A film obtained by subjecting a commercially available optical film to secondary processing such as stretching and / or relaxation can also be used.

  The light transmittance at a wavelength of 590 nm of the retardation film is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. Although the theoretical upper limit of the light transmittance is 100%, surface reflection occurs due to the difference in refractive index between air and the retardation film, and therefore, the upper limit that the light transmittance can be realized is approximately 94%. . It is preferable that the first optical compensation layer as a whole has the same light transmittance.

The absolute value of the photoelastic coefficient of the retardation film is preferably 1.0 × 10 ⁻¹⁰ (m ² / N) or less, more preferably 5.0 × 10 ⁻¹¹ (m ² / N) or less, and still more preferably. Is 3.0 × 10 ⁻¹¹ (m ² / N) or less, particularly preferably 1.0 × 10 ⁻¹¹ (m ² / N) or less. By setting the photoelastic coefficient in such a range, a liquid crystal display device (liquid crystal panel) having excellent optical uniformity and small change in optical characteristics even in an environment such as high temperature and high humidity and excellent durability. Obtainable. The lower limit of the photoelastic coefficient is not particularly limited, but is generally 5.0 × 10 ⁻¹³ (m ² / N) or more, preferably 1.0 × 10 ⁻¹² (m ² / N) or more. If the photoelastic coefficient is too small, there is a possibility that the expression of the phase difference may be reduced. The photoelastic coefficient is a value intrinsic to a chemical structure such as a polymer, but the photoelastic coefficient can be reduced by copolymerizing or mixing a plurality of components having different signs (positive and negative) of the photoelastic coefficient.

  The thickness of the retardation film can be set to any appropriate value depending on the material for forming the retardation film and the configuration of the first optical compensation layer. When the first optical compensation layer is a retardation film alone, the thickness of the first optical compensation layer is preferably 10 to 250 μm, more preferably 20 to 200 μm, and particularly preferably 30 to 150 μm. By having such a thickness, the first optical compensation layer excellent in mechanical strength and display uniformity can be obtained.

E. Second Optical Compensation Layer and Fifth Optical Compensation Layer The second and fifth optical compensation layers each have a refractive index ellipsoid of nx> ny = nz. The second and fifth optical compensation layers can function as so-called λ / 4 plates. The second and fifth optical compensation layers can convert, for example, linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light) as a λ / 4 plate. The in-plane retardation Re2 ₍₅₎ of these optical compensation layers is 80 to 200 nm, preferably 90 to 160 nm, more preferably 110 to 155 nm, and still more preferably 130 to 150 nm. Here, “ny = nz” includes not only the case where ny and nz are exactly equal, but also the case where ny and nz are substantially equal. That is, the Nz coefficient (Rth _{2 (5)} / Re _{2 (5)} ) is more than 0.9 and less than 1.1. The optical characteristics of the second optical compensation layer and the optical characteristics of the fifth optical compensation layer may be different or the same.

  As a material for forming the second and fifth optical compensation layers, any appropriate material can be adopted as long as the above characteristics are obtained. A liquid crystal material is preferable, and a liquid crystal material (nematic liquid crystal) in which the liquid crystal phase is a nematic phase is more preferable. By using the liquid crystal material, the difference between nx and ny of the obtained optical compensation layer can be significantly increased as compared with the non-liquid crystal material. As a result, the thickness of the optical compensation layer for obtaining a desired in-plane retardation can be remarkably reduced, which can contribute to thinning of the liquid crystal panel. As such a liquid crystal material, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal material may exhibit a liquid crystallinity mechanism either lyotropic or thermotropic. The alignment state of the liquid crystal is preferably homogeneous alignment. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

  When the liquid crystal material is a liquid crystal monomer, for example, a polymerizable monomer and / or a crosslinkable monomer is preferable. This is because the alignment state of the liquid crystalline monomer can be fixed by polymerizing or crosslinking the liquid crystalline monomer. After aligning the liquid crystalline monomers, for example, if the liquid crystalline monomers are polymerized or crosslinked, the alignment state can be fixed thereby. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, in the formed second and / or fifth optical compensation layer, for example, transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change specific to the liquid crystal compound does not occur. As a result, the formed second and / or fifth optical compensation layer is an optical compensation layer with extremely high stability that is not affected by temperature changes.

  Specific examples of the method for forming the liquid crystal monomer and the second and fifth optical compensation layers include monomers and methods described in JP-A-2006-178389.

  The thicknesses of the second and fifth optical compensation layers can be set so as to function most appropriately as a λ / 4 plate. In other words, the thickness can be set so as to obtain desired optical characteristics. When the second and / or fifth optical compensation layer is formed of a liquid crystal material, the thickness is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and still more preferably 0.5 to 5 μm. is there.

  The second and fifth optical compensation layers can also be formed by stretching a polymer film. Specifically, by appropriately selecting the type of polymer, stretching conditions (for example, stretching temperature, stretching ratio, stretching direction), stretching method, etc., the desired optical characteristics (for example, refractive index ellipsoid, in-plane The second and / or fifth optical compensation layers having a retardation and a retardation in the thickness direction can be obtained. More specifically, the stretching temperature is preferably 110 to 170 ° C, more preferably 130 to 150 ° C. The draw ratio is preferably 1.37 to 1.67 times, more preferably 1.42 to 1.62 times. Examples of the stretching method include lateral uniaxial stretching.

  When the second and / or fifth optical compensation layer is formed by stretching a polymer film, the thickness is preferably 5 to 55 μm, more preferably 10 to 50 μm, and still more preferably 15 to 45 μm. is there.

  Arbitrary appropriate resin may be employ | adopted as resin which forms the said polymer film. Specific examples include resins constituting a positive birefringent film such as norbornene resin, polycarbonate resin, cellulose resin, polyvinyl alcohol resin, and polysulfone resin. Of these, norbornene resins and polycarbonate resins are preferable.

  The norbornene-based resin is a resin that is polymerized using a norbornene-based monomer as a polymerization unit. Examples of the norbornene-based monomer include norbornene and alkyl and / or alkylidene substituted products thereof such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, and 5-butyl. 2-Norbornene, 5-ethylidene-2-norbornene, etc., polar substituents such as halogens; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, its alkyl and / or alkylidene Substituents and polar group substituents such as halogen such as 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6- Ethyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-oct Hydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5 8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and the like; 3-pentamer of cyclopentadiene, for example, 4,9: 5,8-dimethano-3a, 4 4a, 5,8,8a, 9,9a-octahydro-1H-benzoin 4,11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentanthracene and the like. It is done. The norbornene-based resin may be a copolymer of a norbornene-based monomer and another monomer.

  As the polycarbonate resin, an aromatic polycarbonate is preferably used. The aromatic polycarbonate can be typically obtained by a reaction between a carbonate precursor and an aromatic dihydric phenol compound. Specific examples of the carbonate precursor include phosgene, bischloroformate of dihydric phenols, diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Can be mentioned. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of the aromatic dihydric phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and bis (4-hydroxyphenyl). ) Methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) butane, 2, 2-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl And cyclohexane. You may use these individually or in combination of 2 or more types. Preferably, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are Used. In particular, it is preferable to use both 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

F. Third Optical Compensation Layer and Sixth Optical Compensation Layer Each of the third and sixth optical compensation layers has a refractive index ellipsoid having a relationship of nx = ny> nz. Here, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. That is, Re _{3 (6)} is less than 10 nm. The thickness direction retardation Rth _{3 (6)} of the third and sixth optical compensation layers can be set to any appropriate value according to the configuration of the applied liquid crystal panel. The thickness direction retardation Rth _{3 (6)} is preferably 25 to 300 nm, more preferably 50 to 270 nm, and still more preferably 75 to 250 nm. The optical characteristics of the third optical compensation layer and the optical characteristics of the sixth optical compensation layer may be different or the same. Together with the second and fifth optical compensation layers, the third and sixth optical compensation layers can mainly compensate the liquid crystal cell.

  The third and sixth optical compensation layers can be formed of any appropriate material as long as the above characteristics are obtained. Specific examples of the third and sixth optical compensation layers include cholesteric alignment solidified layers. The “cholesteric alignment solidified layer” refers to a layer in which the constituent molecules of the layer have a helical structure, the helical axis is aligned substantially perpendicular to the plane direction, and the alignment state is fixed. Therefore, the “cholesteric alignment solidified layer” includes not only the case where the liquid crystal compound exhibits a cholesteric liquid crystal phase but also the case where the non-liquid crystal compound has a pseudo structure such as a cholesteric liquid crystal phase. For example, the “cholesteric alignment solidified layer” is obtained by applying a torsion with a chiral agent in a state where the liquid crystal material exhibits a liquid crystal phase and aligning it in a cholesteric structure (spiral structure), and performing a polymerization treatment or a crosslinking treatment in that state. It can be formed by fixing the alignment (cholesteric structure) of the liquid crystal material.

  Specific examples of the cholesteric alignment fixed layer include a cholesteric layer described in JP-A No. 2003-287623.

  The thicknesses of the third and sixth optical compensation layers can be set to any appropriate values as long as the desired optical characteristics are obtained. When the third and / or sixth optical compensation layer is a cholesteric alignment solidified layer, the thickness is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and still more preferably 0.5 to 5 μm.

  Another specific example of the material forming the third and sixth optical compensation layers includes a non-liquid crystalline material. Particularly preferred are non-liquid crystalline polymers. Unlike the liquid crystalline material, such a non-liquid crystalline material can form a film exhibiting an optical uniaxial property of nx = ny> nz by its own property regardless of the orientation of the substrate. As the non-liquid crystalline material, for example, polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide are preferable because they are excellent in heat resistance, chemical resistance, transparency, and rigidity. 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.

  Specific examples of the polyimide and methods for forming the third and sixth optical compensation layers include the polymer and the method for producing an optical compensation film described in JP-A-2004-46065.

  The thicknesses of the third and sixth optical compensation layers can be set to any appropriate values as long as the desired optical characteristics are obtained. When the third and / or sixth optical compensation layer is formed of a non-liquid crystalline material, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and still more preferably 0.5 to 5 μm. .

  Still another specific example of the material forming the third and sixth optical compensation layers includes a polymer film formed of a cellulose resin such as triacetyl cellulose (TAC), a norbornene resin, or the like. As the third and sixth optical compensation layers, commercially available films can be used as they are. Further, a commercially available film subjected to secondary processing such as stretching and / or shrinking can be used. As commercially available films, for example, Fuji Photo Film Co., Ltd. Fujitac series (trade names; ZRF80S, TD80UF, TDY-80UL), Konica Minolta Opto Co., Ltd. trade names “KC8UX2M”, Nippon Zeon Co., Ltd. A trade name “Zeonor”, a product name “Arton” manufactured by JSR Corporation, and the like can be given. The norbornene monomer constituting the norbornene resin is as described above in the section E. Examples of the stretching method for satisfying the above optical characteristics include biaxial stretching (longitudinal and transverse equal magnification stretching).

  The thicknesses of the third and sixth optical compensation layers can be set to any appropriate values as long as the desired optical characteristics are obtained. When the third and / or sixth optical compensation layer is a polymer film formed of a cellulose-based resin, a norbornene-based resin, or the like, it is preferably 45-105 μm, more preferably 55-95 μm, and still more preferably 50- 90 μm.

  Still another specific example of the third and sixth optical compensation layers includes a laminate having the cholesteric alignment solidified layer and a plastic film layer. Examples of the resin forming the plastic film layer include cellulose resins and norbornene resins. These resins are as described above in this section.

  Any appropriate method can be adopted as a method of laminating the cholesteric alignment solidified layer and the plastic film layer. Specifically, a method of transferring the cholesteric alignment solidified layer to the plastic layer, a method of pasting the cholesteric alignment solidified layer previously formed on the base material and the plastic film layer through an adhesive layer, and the like can be mentioned. A typical example of the adhesive that forms the adhesive layer is a curable adhesive. Typical examples of the curable adhesive include a photocurable adhesive such as an ultraviolet curable adhesive, a moisture curable adhesive, and a thermosetting adhesive. The thickness of the adhesive layer is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm.

G. Fourth Optical Compensation Layer The fourth optical compensation layer has a refractive index ellipsoid having a relationship of nx>ny> nz. The in-plane retardation Re ₄ of the fourth optical compensation layer is preferably 80 to 200 nm, more preferably 80 to 150 nm, and still more preferably 80 to 130 nm. The Nz coefficient (Rth ₄ / Re ₄ ) preferably indicates a relationship of 1 <Nz <2, more preferably 1 <Nz <1.5. By providing the fourth optical compensation layer having such optical characteristics, the absorption axis of the polarizer can be suitably compensated, and the screen contrast of the liquid crystal panel when viewed from an oblique direction can be improved. Further, the color shift can be reduced.

  The fourth optical compensation layer can be formed of any appropriate material. Specific examples include stretched films of polymer films. The resin forming the polymer film is preferably a norbornene resin or a polycarbonate resin. Details of these resins are as described above in Section E.

  The polymer film may include any appropriate other thermoplastic resin. Other thermoplastic resins include polyolefin resins, polyvinyl chloride resins, cellulose resins, styrene resins, acrylonitrile / butadiene / styrene resins, acrylonitrile / styrene resins, polymethyl methacrylate, polyvinyl acetate, and polychlorinated resins. General-purpose plastics such as vinylidene resins; general-purpose engineering plastics such as polyamide resins, polyacetal resins, polycarbonate resins, modified polyphenylene ether resins, polybutylene terephthalate resins, polyethylene terephthalate resins; polyphenylene sulfide resins, polysulfone resins , Polyethersulfone resin, polyetheretherketone resin, polyarylate resin, liquid crystalline resin, polyamideimide resin, polyimide resin, polyester Super engineering plastics such as La fluoroethylene resin and the like.

  Arbitrary appropriate methods can be employ | adopted as a preparation method of a stretched film. Examples of the stretching method include lateral uniaxial stretching, free end uniaxial stretching, fixed end biaxial stretching, fixed end uniaxial stretching, and sequential biaxial stretching. A specific example of the fixed-end biaxial stretching includes a method of stretching a polymer film in the short direction (lateral direction) while running in the longitudinal direction. This method can be apparently lateral uniaxial stretching. These stretching methods can be employed singly or in combination of two or more. For example, after performing free end uniaxial stretching, the method of performing fixed end uniaxial stretching, etc. are mentioned. The stretching temperature is preferably 135 to 165 ° C, more preferably 140 to 160 ° C. The draw ratio is preferably 1.2 to 3.2 times, more preferably 1.3 to 3.1 times. In this case, the thickness is typically 20 to 80 μm, preferably 25 to 75 μm, and more preferably 30 to 60 μm.

  Another specific example of forming the fourth optical compensation layer is a non-liquid crystalline material. Non-liquid crystalline polymers are preferred. Specifically, polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide are preferable. These polymers may be used alone or in a mixture of two or more. Among these, polyimide is particularly preferable because of high transparency, high orientation, and high stretchability.

  The fourth optical compensation layer can be typically formed by applying a solution of the non-liquid crystalline polymer to a base film and removing the solvent. In the method for forming the optical compensation layer, a process (for example, a stretching process) for imparting optical biaxiality (nx> ny> nz) is preferably performed. By performing such processing, a difference in refractive index (nx> ny) can be reliably imparted in the surface. In addition, as a specific example of the said polyimide and the specific example of the formation method of the said optical compensation layer, the manufacturing method of the polymer and optical compensation film of Unexamined-Japanese-Patent No. 2004-46065 are mentioned. In this case, the thickness of the fourth optical compensation layer is typically 0.1 to 10 μm, preferably 0.1 to 8 μm, and more preferably 0.1 to 5 μm.

H. Protective layer The said 1st-4th protective layer is formed with the arbitrary appropriate films which can be used as a protective film of a polarizing plate. Specific examples of the material that is the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, 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 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 mentioned. The polymer film can be, for example, an extruded product of the resin composition.

  As said (meth) acrylic-type resin, Tg (glass transition temperature) becomes like this. Preferably it is 115 degreeC or more, More preferably, it is 120 degreeC or more, More preferably, it is 125 degreeC or more, Most preferably, it is 130 degreeC or more. It is because it can be excellent in durability. Although the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From viewpoints of a moldability etc., Preferably it is 170 degrees C or less.

As said (meth) acrylic-type resin, arbitrary appropriate (meth) acrylic-type resins can be employ | adopted within the range which does not impair the effect of this invention. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylic acid C _1-6 alkyl such as poly (meth) acrylate methyl is used. More preferably, a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  Specific examples of the (meth) acrylic resin include (meth) acrylic resins having a ring structure in the molecule described in, for example, Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. Examples of the resin include high Tg (meth) acrylic resins obtained by intramolecular crosslinking or intramolecular cyclization reaction.

  As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure is particularly preferable in that it has high heat resistance, high transparency, and high mechanical strength.

  Examples of the (meth) acrylic resin having the lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include (meth) acrylic resins having a lactone ring structure described in JP-A-146084.

  The (meth) acrylic resin having the lactone ring structure has a mass average molecular weight (sometimes referred to as a weight average molecular weight) of preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, and still more preferably 10,000 to 500,000. Preferably it is 50000-500000.

  The (meth) acrylic resin having the lactone ring structure has a Tg (glass transition temperature) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, still more preferably 130 ° C. or higher, particularly preferably 135 ° C. or higher. Preferably it is 140 degreeC or more. It is because it can be excellent in durability. The upper limit of Tg of the (meth) acrylic resin having the lactone ring structure is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like.

  In the present specification, “(meth) acrylic” refers to acrylic and / or methacrylic.

  The first to fourth protective layers are preferably transparent and have no color. The thickness direction retardation Rth of the first to fourth protective layers is preferably −90 nm to +90 nm, more preferably −80 nm to +80 nm, and still more preferably −70 nm to +70 nm.

  Any appropriate thickness can be adopted as the thickness of the first to fourth protective layers as long as the preferable thickness direction retardation Rth can be obtained. The thickness of the second and fourth protective layers is typically 5 mm or less, preferably 1 mm or less, more preferably 1 to 500 μm, and further preferably 5 to 150 μm.

  On the opposite side of the second and fourth protective layers from the polarizer, a hard coat treatment, an antireflection treatment, an antisticking treatment, an antiglare treatment, or the like can be performed as necessary.

  The first protective layer provided between the first polarizer and the first optical compensation layer, and the third protective layer provided between the second polarizer and the fourth optical compensation layer. It is preferable that the thickness direction retardation (Rth) is smaller than the above preferable value. As described above, in the case of a cellulose film generally used as a protective film, for example, a triacetyl cellulose film, the thickness direction retardation (Rth) is about 60 nm at a thickness of 80 μm. Thus, the cellulose film having a large thickness direction retardation (Rth) is preferably subjected to an appropriate treatment for reducing the thickness direction retardation (Rth), whereby the first and third protective layers are preferably obtained. be able to.

  Any appropriate treatment method can be adopted as the treatment for reducing the retardation (Rth) in the thickness direction. For example, a base material such as polyethylene terephthalate, polypropylene, and stainless steel coated with a solvent such as cyclopentanone and methyl ethyl ketone is bonded to a general cellulose film and dried by heating (for example, about 80 to 150 ° C. for 3 to 10 minutes) After removing the base film, a solution obtained by dissolving norbornene resin, acrylic resin or the like in a solvent such as cyclopentanone or methyl ethyl ketone is applied to a general cellulose film and dried by heating (for example, And a method of peeling the coated film after about 3 to 10 minutes at about 80 to 150 ° C.).

  The material constituting the cellulose film is preferably a fatty acid-substituted cellulose polymer such as diacetyl cellulose or triacetyl cellulose. Generally used triacetyl cellulose has an acetic acid substitution degree of about 2.8, preferably an acetic acid substitution degree of 1.8 to 2.7, more preferably a propionic acid substitution degree of 0.1 to 2.7. By controlling to 1, the thickness direction retardation (Rth) can be controlled to be small.

  By adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide, and acetyltriethyl citrate to the fatty acid-substituted cellulose polymer, the thickness direction retardation (Rth) can be controlled small. The addition amount of the plasticizer is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, and still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the fatty acid-substituted cellulose polymer.

  The processes for reducing the thickness direction retardation (Rth) may be used in appropriate combination. The thickness direction retardation Rth (550) of the first and third protective layers obtained by such treatment is preferably −20 nm to +20 nm, more preferably −10 nm to +10 nm, and still more preferably −6 nm to +6 nm, particularly preferably -3 nm to +3 nm. The in-plane retardation Re (550) of the first and third protective layers is preferably 0 nm to 10 nm, more preferably 0 nm to 6 nm, and still more preferably 0 nm to 3 nm.

  Any appropriate thickness can be adopted as the thickness of the first and third protective layers as long as the preferable thickness direction retardation Rth can be obtained. The thickness of the first and third protective layers is preferably 20 to 200 μm, more preferably 30 to 100 μm, and still more preferably 35 to 95 μm.

I. Method for Producing Liquid Crystal Panel The liquid crystal panel can be produced, for example, by sequentially laminating the above components (first to sixth optical compensation layers, first and second polarizers, etc.) in a liquid crystal cell. Further, for example, a first laminated optical film (indicated by reference numeral 10 in FIG. 1) in which a first polarizer and first to third optical compensation layers are sequentially laminated, a second polarizer, A second laminated optical film (indicated by reference numeral 30 in FIG. 1) in which 4 to 6 optical compensation layers are sequentially laminated is manufactured, and then the first and second laminated optical films are liquid crystal cells. It may be produced by pasting together.

  Any appropriate method can be adopted as a method of laminating each component of the liquid crystal panel. Typically, it is laminated via any suitable pressure-sensitive adhesive layer or adhesive layer (not shown). For example, as described above, in the case where the fourth optical compensation layer 15 can function as a protective layer of the second polarizer 11 ′, the second polarizer and the fourth optical compensation layer are bonded to each other appropriately. It is laminated through the agent layer. At this time, if the fourth optical compensation layer is formed by fixed-end biaxial stretching, the slow axis may be generated in the short direction. On the other hand, the absorption axis direction of the polarizer can occur in the stretching direction (longitudinal direction). Therefore, in the case where the slow axis of the fourth optical compensation layer is arranged so as to be orthogonal to the absorption axis of the second polarizer, the fourth optical compensation layer and the second polarizer are roll-to-roll. A roll (a long fourth optical compensation layer and a long polarizing film (second polarizer) may be continuously laminated with their respective longitudinal directions aligned).

  Any appropriate pressure-sensitive adhesive layer may be used as the pressure-sensitive adhesive layer. A typical example is an acrylic pressure-sensitive adhesive layer. The thickness of the acrylic pressure-sensitive adhesive layer provided on both sides of the liquid crystal cell is preferably 1 μm to 100 μm, more preferably 1 μm to 50 μm, and further preferably 3 μm to 30 μm. The thickness of the other acrylic pressure-sensitive adhesive layer is preferably 1 to 30 μm, more preferably 3 to 25 μm.

  Any appropriate adhesive layer may be used as the adhesive layer. For example, the adhesive used for laminating the second polarizer and the fourth optical compensation layer is preferably an adhesive containing a polyvinyl alcohol-based resin, a crosslinking agent, and a metal compound colloid.

  Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol resins and acetoacetyl group-containing polyvinyl alcohol resins. Preferably, it is an acetoacetyl group-containing polyvinyl alcohol resin. This is because durability can be improved.

  Examples of the polyvinyl alcohol resin include a saponified product of polyvinyl acetate, a derivative of the saponified product; a saponified product of a copolymer with vinyl acetate and a monomer having copolymerizability; Examples thereof include modified polyvinyl alcohols that have been converted into ethers, ethers, grafts, or phosphoric esters. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, and (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene; (Meth) allyl sulfonic acid (soda), sulfonic acid soda (monoalkyl malate), disulfonic acid soda alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N-vinyl pyrrolidone, N-vinyl pyrrolidone derivatives, etc. Can be mentioned. These resins can be used alone or in combination of two or more.

  The average degree of polymerization of the polyvinyl alcohol-based resin is preferably about 100 to 5000, and more preferably 1000 to 4000, from the viewpoint of adhesiveness. The average saponification degree is preferably about 85 to 100 mol%, more preferably 90 to 100 mol% from the viewpoint of adhesiveness.

  The acetoacetyl group-containing polyvinyl alcohol resin can be obtained, for example, by reacting a polyvinyl alcohol resin and diketene by an arbitrary method. As a specific example, a method in which diketene is added to a dispersion in which a polyvinyl alcohol resin is dispersed in a solvent such as acetic acid; diketene is added to a solution in which the polyvinyl alcohol resin is dissolved in a solvent such as dimethylformamide or dioxane. A method of directly contacting a diketene gas or liquid diketene with a polyvinyl alcohol resin.

  The degree of acetoacetyl group modification of the acetoacetyl group-containing polyvinyl alcohol resin is typically 0.1 mol% or more, preferably about 0.1 to 40 mol%, more preferably 1 to 20%, particularly Preferably it is 2-7 mol%. If it is less than 0.1 mol%, the water resistance may be insufficient. If it exceeds 40 mol%, the effect of improving water resistance is small. The degree of acetoacetyl group modification is a value measured by NMR.

  Any appropriate crosslinking agent can be adopted as the crosslinking agent. A compound having at least two functional groups having reactivity with the polyvinyl alcohol resin is preferable. For example, ethylenediamine, triethylenediamine, hexamethylenediamine and other alkylene diamines having two amino groups and amino groups; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane triisocyanate, isophorone diisocyanate and isocyanates such as ketoxime block product or phenol block product thereof; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexane Diol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycy Epoxys such as ruaniline and diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde; Amino-formaldehyde resins such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde; sodium, potassium, magnesium, calcium, aluminum, iron, nickel, etc. Among them, amino-formaldehyde resins and dialdehydes are preferred. There Amino -.. Preferably a compound having a methylol group as a formaldehyde resin, the dialdehydes are preferred glyoxal Of these compounds having a methylol group is preferable, and methylol melamine is particularly preferred.

  The blending amount of the crosslinking agent can be appropriately set according to the type of the polyvinyl alcohol resin. Typically, it is about 10 to 60 parts by weight, preferably 20 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. This is because the adhesiveness can be excellent. In addition, when there are many compounding quantities of a crosslinking agent, reaction of a crosslinking agent advances in a short time, and there exists a tendency for an adhesive agent to gelatinize. As a result, the usable time (pot life) as an adhesive becomes extremely short, and industrial use may be difficult. Since the adhesive of this embodiment contains a metal compound colloid described later, it can be used with good stability even when the amount of the crosslinking agent is large.

  The metal compound colloid may be one in which metal compound fine particles are dispersed in a dispersion medium, and is electrostatically stabilized due to mutual repulsion of the same kind of charge of the fine particles, and has permanent stability. obtain. The average particle size of the fine particles forming the metal compound colloid can be any appropriate value as long as it does not adversely affect the optical properties such as polarization properties. Preferably it is 1-100 nm, More preferably, it is 1-50 nm. This is because the fine particles can be uniformly dispersed in the adhesive layer, the adhesion can be ensured, and the nick can be suppressed. Note that “knic” refers to a local uneven defect generated at the interface between the polarizer and the protective layer (first optical compensation layer).

  Any appropriate compound can be adopted as the metal compound. For example, metal oxides such as alumina, silica, zirconia and titania; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate and calcium phosphate; minerals such as celite, talc, clay and kaolin It is done. Alumina is preferred.

  The metal compound colloid is typically present in the form of a colloidal solution dispersed in a dispersion medium. Examples of the dispersion medium include water and alcohols. The solid content concentration in the colloidal solution is typically about 1 to 50% by weight. The colloidal solution can contain acids such as nitric acid, hydrochloric acid, acetic acid as stabilizers.

  The compounding amount of the metal compound colloid (solid content) is preferably 200 parts by weight or less, more preferably 10 to 200 parts by weight, still more preferably 20 to 175 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. Most preferably, it is 30-150 weight part. This is because the occurrence of nicks can be suppressed while ensuring adhesiveness.

  The adhesive of this embodiment includes coupling agents such as silane coupling agents and titanium coupling agents, various tackifiers, ultraviolet absorbers, antioxidants, heat stabilizers, stabilizers such as hydrolysis stabilizers, etc. Can be included.

  The form of the adhesive of this embodiment is preferably an aqueous solution (resin solution). The resin concentration is preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, from the viewpoints of coatability and storage stability. The viscosity of the resin solution is preferably 1 to 50 mPa · s. The pH of the resin solution is preferably 2 to 6, more preferably 2.5 to 5, further preferably 3 to 5, and most preferably 3.5 to 4.5. Usually, the surface charge of the metal compound colloid can be controlled by adjusting the pH. The surface charge is preferably a positive charge. By having a positive charge, for example, generation of nicks can be suppressed.

  Arbitrary appropriate methods can be employ | adopted for the preparation method of the said resin solution. For example, a method in which a metal compound colloid is mixed with a polyvinyl alcohol-based resin and a cross-linking agent that are mixed in advance and adjusted to an appropriate concentration. Moreover, after mixing a polyvinyl alcohol-type resin and a metal compound colloid, a crosslinking agent can also be mixed considering the time of use etc. The concentration of the resin solution may be adjusted after preparing the resin solution.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The measuring method of each characteristic is as follows.

(1) Measurement of phase difference value The phase difference value was automatically measured using KOBRA-WPR manufactured by Oji Scientific. The measurement wavelength was 590 nm or 550 nm, and the measurement temperature was 23 ° C.
(2) Measurement of contrast A white image and a black image were displayed on a liquid crystal display device, and measurement was performed using a product name “Conoscope” manufactured by AUTRONIC MELCHERS.

[Example 1]
(Polarizer)
The polyvinyl alcohol film was dyed in an aqueous solution containing iodine and then uniaxially stretched 6 times between rolls having different speed ratios in an aqueous solution containing boric acid to obtain a polarizer. A triacetyl cellulose film (thickness 40 μm, manufactured by Konica Minolta, Inc., trade name: KC4UYW) was attached to both surfaces of the polarizer via a polyvinyl alcohol adhesive (thickness 0.1 μm) as a protective layer. The in-plane retardation Re (550) of the protective layer was 0.9 nm, and the thickness direction retardation Rth (550) was 1.2 nm. In this way, a polarizing plate was produced. Re (550) represents a value when measured with light having a wavelength of 550 nm at 23 ° C.

(First optical compensation layer)
Styrene-maleic anhydride copolymer (manufactured by Nova Chemical Japan Co., Ltd., trade name “Dylark D232”) is extruded at 270 ° C. using a single screw extruder and a T die, and melted in a sheet form. The resin was cooled with a cooling drum to obtain a film having a thickness of 100 μm. This film was uniaxially stretched in the transport direction at a temperature of 130 ° C. and a stretch ratio of 1.6 times using a roll stretching machine to obtain a film having a fast axis in the transport direction (longitudinal stretching step). .
Using a tenter stretching machine, the obtained film was uniaxially stretched at a fixed end in the width direction so that the film width was 1.6 times the film width after the longitudinal stretching at a temperature of 135 ° C., and the thickness was 50 μm. A biaxially stretched film was obtained (transverse stretching step).
The retardation film thus obtained has a fast axis in the transport direction, the refractive index ellipsoid shows a relationship of nz>nx> ny, the in-plane retardation Re ₁ is 19 nm, and the thickness direction The phase difference Rth ₁ was −80 nm, and the Nz coefficient (Rth ₁ / Re ₁ ) was −4.2. The obtained retardation film was punched into a size corresponding to a liquid crystal cell described later to obtain a first optical compensation layer.

(Second optical compensation layer)
By uniaxially stretching a long norbornene-based resin film (manufactured by Nippon Zeon Co., Ltd., trade name Zeonor, thickness 40 μm, photoelastic coefficient 3.10 × 10 ⁻¹² m ² / N) at 140 ° C. by 1.52 times, A long film was prepared. The thickness of the obtained film was 35 μm, the in-plane retardation Re ₂ was 140 nm, and the thickness direction retardation Rth ₂ was 140 nm. The obtained film was punched out to a size corresponding to a liquid crystal cell described later to obtain a second optical compensation layer.

(Third optical compensation layer)
90 parts by weight of a nematic liquid crystalline compound represented by the following chemical formula (1), 10 parts by weight of a chiral agent represented by the following chemical formula (2), 5 parts by weight of a photopolymerization initiator (Irgacure 907: manufactured by Ciba Specialty Chemicals), and 300 parts by weight of methyl ethyl ketone was mixed uniformly to prepare a liquid crystal coating solution. Next, this liquid crystal coating solution is coated on a substrate (biaxially stretched PET film), heat-treated at 80 ° C. for 3 minutes, and then subjected to polymerization treatment by irradiating with ultraviolet rays, and a third optical compensation layer and A cholesteric alignment solidified layer was formed. The thickness of the cholesteric alignment fixed layer was 2.2 μm, the thickness direction retardation Rth ₃ was 120 nm, and the in-plane retardation Re ₃ was substantially zero.

(Fourth optical compensation layer)
A long norbornene-based resin film (manufactured by Nippon Zeon Co., Ltd., trade name: Zeonor, thickness: 60 μm, photoelastic coefficient: 3.1 × 10 ⁻¹² m ² / N) is uniaxially stretched at 158 ° C. by 3.0 times. As a result, a long film was produced. The in-plane retardation Re ₄ of the obtained film was 110 nm, the thickness direction retardation Rth ₄ was 143 nm, and the Nz coefficient (Rth ₄ / Re ₄ ) was 1.3. The obtained film was punched out to a size corresponding to a liquid crystal cell described later to obtain a fourth optical compensation layer.

(Fifth optical compensation layer)
A film obtained in the same manner as the second optical compensation layer was used as a fifth optical compensation layer (Re ₅ : 140 nm, Rth ₅ : 140 nm).

(Sixth optical compensation layer)
A cholesteric alignment solidified layer obtained in the same manner as the third optical compensation layer was used as a sixth optical compensation layer (Re ₆ : substantially zero, Rth ₆ : 120 nm).

(Laminated film A)
A cholesteric alignment solidified layer as a third optical compensation layer is adhered to the second optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate 1 in which the cholesteric alignment solidified layer was transferred to the second optical compensation layer was obtained.
On the second optical compensation layer side of the laminate 1, the first optical compensation layer and the polarizing plate were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm). At this time, the first optical compensation layer is laminated so that the slow axis of the first optical compensation layer is parallel to the absorption axis of the polarizer of the polarizing plate, and the slow axis of the second optical compensation layer is of the polarizer of the polarizing plate. The layers were laminated so as to be 45 ° clockwise with respect to the absorption axis. Thus, a laminated film A was produced.

(Laminated film B)
A cholesteric alignment solidified layer to be the sixth optical compensation layer is adhered to the fifth optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate 2 in which the cholesteric alignment solidified layer was transferred to the fifth optical compensation layer was obtained.
On the fifth optical compensation layer side of the laminate 2, a fourth optical compensation layer and a polarizing plate were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12 μm). At this time, the fourth optical compensation layer is laminated so that the slow axis of the fourth optical compensation layer is orthogonal to the absorption axis of the polarizer of the polarizing plate, and the slow axis of the fifth optical compensation layer is the absorption of the polarizer of the polarizing plate. The layers were laminated so as to be 45 ° clockwise with respect to the axis. Thus, a laminated film B was produced.

(LCD panel)
The liquid crystal cell was removed from the Sony PlayStation Portable (VA mode liquid crystal cell mounted), and the laminated film A was attached to the viewing side of the liquid crystal cell via an acrylic adhesive (thickness 20 μm). At this time, the third optical compensation layer was attached so as to be on the liquid crystal cell side. Moreover, the said laminated | multilayer film B was affixed on the backlight side of the liquid crystal cell through the acrylic adhesive (thickness 20 micrometers). At this time, the sixth optical compensation layer was attached so as to be on the liquid crystal cell side. Moreover, it laminated | stacked so that the absorption axis of the polarizer of the laminated | multilayer film A and the absorption axis of the polarizer of the laminated | multilayer film B might mutually cross substantially orthogonally. Specifically, the slow axis of the first optical compensation layer is 0 ° and the slow axis of the second optical compensation layer is clockwise with respect to the absorption axis of the polarizer on the viewing side as a reference (0 °). The laminated layers were 45 °, the slow axis of the fifth optical compensation layer was 135 °, the slow axis of the fourth optical compensation layer was 0 °, and the absorption axis of the polarizer on the backlight side was 90 °. A liquid crystal panel was thus produced.
The viewing angle dependence of the contrast of a liquid crystal display device manufactured using the liquid crystal panel thus obtained was measured. The results are shown in FIG.

[Example 2]
(Laminated film C)
A laminated film C was obtained in the same manner as the laminated film A, except that the slow axis of the first optical compensation layer was laminated so as to be orthogonal to the absorption axis of the polarizer of the polarizing plate.
(Laminated film D)
A laminated film D was obtained in the same manner as the laminated film B except that the fourth optical compensation layer was laminated so that the slow axis of the fourth optical compensation layer was parallel to the absorption axis of the polarizer of the polarizing plate.

(LCD panel)
A liquid crystal panel was obtained in the same manner as in Example 1 except that the laminated film C was used instead of the laminated film A, and that the laminated film D was used instead of the laminated film B. Specifically, the slow axis of the first optical compensation layer is 90 ° and the slow axis of the second optical compensation layer is clockwise with respect to the absorption axis of the polarizer on the viewing side as a reference (0 °). Laminated so that the slow axis of the fifth optical compensation layer is 135 °, the slow axis of the fourth optical compensation layer is 90 °, and the absorption axis of the polarizer on the backlight side is 90 °. A liquid crystal panel was obtained.
The viewing angle dependence of the contrast of a liquid crystal display device manufactured using the liquid crystal panel thus obtained was measured. The results are shown in FIG.

[Comparative Example 1]
(Laminated film E)
A laminated film E was obtained in the same manner as the laminated film A, except that the first optical compensation layer was not laminated.
(Laminated film F)
A laminated film F was obtained in the same manner as the laminated film B, except that the fourth optical compensation layer was not laminated.

(LCD panel)
A liquid crystal panel was obtained in the same manner as in Example 1 except that the laminated film E was used instead of the laminated film A, and that the laminated film F was used instead of the laminated film B. Specifically, the slow axis of the second optical compensation layer is 45 ° and the slow axis of the fifth optical compensation layer is clockwise, with the absorption axis of the polarizer on the viewing side as a reference (0 °). A liquid crystal panel was manufactured by stacking the polarizer so that the absorption axis of the polarizer on the backlight side was 90 °.
The viewing angle dependence of the contrast of a liquid crystal display device manufactured using the liquid crystal panel thus obtained was measured. The results are shown in FIG.

  Table 1 summarizes the overall configuration of the panels of Examples 1 and 2 and Comparative Example 1. The angle (clockwise) when the absorption axis of the viewing side polarizer is 0 ° is also shown.

  As is clear from FIGS. 3 to 5, the liquid crystal panels of Examples 1 and 2 of the present invention were superior in contrast to the liquid crystal panel of Comparative Example 1. Moreover, it was confirmed that the liquid crystal panel of the Example of this invention has a small color shift compared with the liquid crystal panel of a comparative example.

  The liquid crystal panel and the liquid crystal display device of the present invention can be suitably applied to a mobile phone, a personal digital assistant (PDA), a liquid crystal television, a personal computer, and the like.

1 is a schematic cross-sectional view of a liquid crystal panel according to one preferred embodiment of the present invention. When the liquid crystal display device of this invention employ | adopts a VA mode liquid crystal cell, it is a schematic sectional drawing explaining the orientation state of the liquid crystal molecule of a liquid crystal layer. It is a contrast contour map which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 1 of this invention. It is a contrast contour map which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 2 of this invention. 6 is a contrast contour map showing the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st laminated optical film 30 2nd laminated optical film 11 1st polarizer 11 '2nd polarizer 12 1st optical compensation layer 13 2nd optical compensation layer 14 3rd optical compensation layer 15 1st 4 optical compensation layer 16 5th optical compensation layer 17 6th optical compensation layer 20 Liquid crystal cell 100 Liquid crystal panel

Claims (8)

A liquid crystal cell;
A first polarizer disposed on one side of the liquid crystal cell;
A first optical compensation layer, in which a refractive index ellipsoid is disposed in order from the first polarizer side between the liquid crystal cell and the first polarizer and has a relationship of nz>nx> ny, a refractive index The ellipsoid shows a relationship of nx> ny = nz, the second optical compensation layer having an in-plane retardation Re ₂ of 80 to 200 nm, and the refractive index ellipsoid shows a relationship of nx = ny> nz. An optical compensation layer of
A second polarizer disposed on the other side of the liquid crystal cell;
A fourth optical compensation layer, in which a refractive index ellipsoid having a relationship of nx>ny> nz is disposed between the liquid crystal cell and the second polarizer in order from the second polarizer side; The ellipsoid shows a relationship of nx> ny = nz, the fifth optical compensation layer has an in-plane retardation Re ₅ of 80 to 200 nm, and the refractive index ellipsoid shows a relationship of nx = ny> nz. An optical compensation layer of
LCD panel with.   The liquid crystal panel according to claim 1, wherein the first polarizer is disposed on the viewing side.   The liquid crystal panel according to claim 1, wherein the first polarizer is disposed on a backlight side.   4. The liquid crystal panel according to claim 1, wherein an absorption axis of the first polarizer and a slow axis of the first optical compensation layer are arranged in parallel or orthogonal to each other. 5.   5. The liquid crystal panel according to claim 1, wherein an absorption axis of the second polarizer and a slow axis of the fourth optical compensation layer are arranged in parallel or orthogonal to each other.   The liquid crystal panel according to claim 1, wherein an Nz coefficient of the first optical compensation layer is −1.0 or less.   The liquid crystal panel according to claim 1, wherein the liquid crystal cell is in a VA mode.   A liquid crystal display device comprising the liquid crystal panel according to claim 1.