JP4911603B2 - Liquid crystal panel and liquid crystal display device - Google Patents

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 panel and a liquid crystal display device having at least three optical compensation layers on both sides of the liquid crystal cell.

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

  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. from arranged in this order, the refractive index ellipsoid showed a relationship of nx> ny = nz, the first optical compensation layer plane retardation Re ₁ is 80 to 300 nm, the refractive index ellipsoid nx> ny = nz A second optical compensation layer having an in-plane retardation Re ₂ of 80 to 200 nm, a third optical compensation layer having a refractive index ellipsoid showing a relationship of nx = ny> nz, and the liquid crystal A refractive index ellipsoid arranged in order from the second polarizer side between the second polarizer disposed on the other side of the cell and the liquid crystal cell and the second polarizer is nz> the fourth optical compensation layer having a relationship of nx = ny, the refractive index ellipsoid showed a relationship of nx> ny = nz, an in-plane retardation Re ₅ Fifth optical compensation layer 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 disposed 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 orthogonally.

  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, since the liquid crystal panel includes at least three predetermined optical compensation layers on both sides of the liquid crystal cell, the screen contrast can be improved and the color shift can be reduced.

  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 (that is, the slow axis direction), “ny” is the refractive index in the direction perpendicular to the slow axis in the plane, and “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 / 2 plate The λ / 2 plate is an electro-optic birefringent plate that serves to rotate the polarization plane of the light beam, and ½ wavelength between linearly polarized light that vibrates in directions perpendicular to each other. It has the function which produces the optical path difference of. That is, it acts to shift the phase between the ordinary ray component and the extraordinary ray component by a half cycle.
(6) 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. That is, it means that the phase between the ordinary ray component and the extraordinary ray component acts so as to be shifted by a quarter cycle and converts circularly polarized light into plane polarized light (or plane polarized light into circularly polarized light).

A. 1 is a schematic sectional view of a liquid crystal panel according to a preferred embodiment of the present invention. The liquid crystal panel 100 includes a liquid crystal cell 20, a first polarizer 11 disposed on one side (viewing side in the illustrated example) of the liquid crystal cell 20, and the liquid crystal cell 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 other of the liquid crystal cell 20, which are sequentially disposed between the first polarizer 11 and the liquid crystal cell 20. 2nd polarizer 11 'arrange | positioned by the side (backlight side in the example of illustration), and arrange | positions in order from this 2nd polarizer 11' side between this liquid crystal cell and this 2nd polarizer 11 '. The fourth optical compensation layer 15, the fifth optical compensation layer 16, and the sixth optical compensation layer 17 are provided. 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. If necessary, a third protective layer is provided between the second polarizer 11 ′ and the fourth optical compensation layer 15, and the fourth optical compensation layer 15 of the second polarizer 11 ′. A fourth protective layer is provided on the opposite side. 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 illustrated example, the first polarizer 11 is disposed on the viewing side of the liquid crystal cell 20, and the second polarizer 11 ′ is disposed on the backlight side, but the first polarizer 11 is disposed on the liquid crystal cell 20. The second polarizer 11 ′ may be arranged on the viewing side, arranged on the backlight side.

  The first optical compensation layer 12 has a refractive index ellipsoid of nx> ny = nz. The first optical compensation layer 12 and the first polarizer 11 are arranged such that the absorption axis and the slow axis define an arbitrary appropriate angle. 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 orthogonal to each other. By configuring such a positional relationship, the screen contrast can be further improved and the color shift can be further reduced. In the present specification, the term “orthogonal” includes the 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 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 defines any appropriate angle with respect to the absorption axis of the first polarizer 11. The angle is preferably 37 ° to 52 °, more preferably 40 ° to 50 °, further preferably 42 ° to 48 °, and particularly preferably about 45 °. By configuring such a positional relationship, the screen contrast can be further improved and the color shift can be further reduced.

  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 defines any appropriate angle with respect to the absorption axis of the second polarizer 11 ′. The angle is preferably 37 ° to 52 °, more preferably 40 ° to 50 °, further preferably 42 ° to 48 °, and particularly preferably about 45 °. By configuring such a positional relationship, the screen contrast can be further improved and the color shift can be further reduced.

  The first polarizer 11 and the second polarizer 11 'are typically arranged such that their absorption axes are substantially orthogonal to each other.

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 can be adopted as the first polarizer 11 and the second polarizer 11 ′ according to 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 The first optical compensation layer 12 has a refractive index ellipsoid having a relationship of nx> ny = nz. The in-plane retardation Re ₁ of the first optical compensation layer is 80 to 300 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 ₁ / Re ₁ ) is more than 0.9 and less than 1.1.

In one preferred embodiment, the first optical compensation layer can function as a λ / 4 plate. In this case, the in-plane retardation Re ₁ is preferably 90 to 160 nm, more preferably 110 to 155 nm, and particularly preferably 130 to 150 nm. In another preferred embodiment, the first optical compensation layer can function as a λ / 2 plate. In this case, the in-plane retardation Re ₁ is preferably 200 to 300 nm, more preferably 230 to 290 nm, and particularly preferably 260 to 280 nm. The first optical compensation layer can compensate the optical axis of the polarizer and can improve the screen contrast when viewed from an oblique direction. As described above, the contrast can be further improved by arranging the first optical compensation layer so that the slow axis thereof is orthogonal to the absorption axis of the first polarizer.

  The first optical compensation layer can be formed of any appropriate material 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, and the resulting laminated optical film and liquid crystal panel can be made thinner. 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. Accordingly, in the formed first optical compensation layer, for example, a 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 first 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 first optical compensation layer include monomers and methods described in JP-A No. 2006-178389.

  When the first 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 particularly preferably 0.5 to 5 μm.

  The first optical compensation layer can also be formed by stretching a polymer film. That is, it can be a stretched film of 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 An optical compensation layer having a retardation and a retardation in the thickness direction can be obtained. Specifically, when the stretched film can function as a λ / 2 plate, the stretching temperature is preferably 120 to 160 ° C, more preferably 130 to 150 ° C. The draw ratio is preferably 2.0 to 2.5 times, more preferably 2.1 to 2.4 times. Examples of the stretching method include lateral uniaxial stretching. The stretched film typically has a thickness of 5 to 55 μm, preferably 15 to 50 μm, and more preferably 20 to 45 μm.

  On the other hand, when the stretched film can function as a λ / 4 plate, 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. The stretched film typically has a thickness of 5 to 55 μm, preferably 10 to 50 μm, and more preferably 15 to 45 μm.

  Arbitrary appropriate polymers 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, and the like, polar substituents such as halogens thereof; 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.

E. Second Optical Compensation Layer The second optical compensation layer 13 has a refractive index ellipsoid of nx> ny = nz. 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 / Re ₂ ) is more than 0.9 and less than 1.1. The in-plane retardation Re ₂ of the second optical compensation layer is 80 to 200 nm, preferably 90 to 160 nm, more preferably 110 to 155 nm, and particularly preferably 130 to 150 nm. That is, it can function as a λ / 4 plate. As the λ / 4 plate, for example, the second optical compensation layer can convert linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light).

  The second optical compensation layer can be formed of any appropriate material. Specific examples include the liquid crystal material described in the above section D. When formed of the liquid crystal material, the thickness is typically 0.5 to 10 μm, preferably 0.5 to 8 μm, and more preferably 0.5 to 5 μm.

  Another specific example of the second optical compensation layer is the stretched polymer film described in the above section D. When it is the said stretched film, thickness is 5-55 micrometers typically, Preferably it is 10-50 micrometers, More preferably, it is 15-45 micrometers. The stretching temperature of this stretched film 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.

F. Third Optical Compensation Layer The third optical compensation layer 14 has a refractive index ellipsoid 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 is less than 10 nm. The thickness direction retardation Rth ₃ of the third optical compensation layer can be set to any appropriate value. Preferably it is 25-300 nm, More preferably, it is 50-270 nm, Most preferably, it is 75-250 nm.

  The third optical compensation layer can be formed of any appropriate material as long as the above characteristics are obtained. A specific example of the third optical compensation layer is a cholesteric alignment solidified layer. 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 thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is a cholesteric alignment fixed layer, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

  Another specific example of the material forming the third optical compensation layer is 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 the method for forming the third optical compensation layer include a polymer and a method for producing an optical compensation film described in JP-A-2004-46065.

  The thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is formed of a non-liquid crystal material, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

  Still another specific example of the material forming the third optical compensation layer includes a polymer film formed of a cellulose resin such as triacetyl cellulose (TAC), a norbornene resin, or the like. A commercially available film can be used as it is as the third optical compensation layer. 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-based monomer constituting the norbornene-based resin is as described above in the section A-2. Examples of the stretching method for satisfying the above optical characteristics include biaxial stretching (longitudinal and transverse equal magnification stretching).

  The thickness of the third optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the third optical compensation layer is a polymer film formed of a cellulose resin, a norbornene resin or the like, the thickness is preferably 45 to 105 μm, more preferably 55 to 95 μm, and particularly preferably 50 to 90 μm.

  Another specific example of the third optical compensation layer 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. 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 15 has a refractive index ellipsoid having a relationship of nz> nx = ny. In this case, the thickness direction retardation Rth ₄ is preferably −50 to −300 nm, more preferably −70 to −250 nm, particularly preferably −90 to −200 nm, and most preferably −100 to −180 nm. 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 ₄ is less than 10 nm.

  The fourth optical compensation layer can be formed of any appropriate material. Preferably, it consists of a film containing a liquid crystal material fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the method for forming the liquid crystal compound and the optical compensation layer include the liquid crystal compounds described in JP-A-2002-333642 [0020] to [0042] and the method for forming the film. In this case, the thickness of the film is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

H. Fifth Optical Compensation Layer The fifth optical compensation layer 16 has a refractive index ellipsoid of nx> ny = nz. 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 ₅ / Re ₅ ) is more than 0.9 and less than 1.1. The in-plane retardation Re ₅ of the fifth optical compensation layer is 80 to 200 nm, preferably 90 to 160 nm, more preferably 110 to 155 nm, and particularly preferably 130 to 150 nm. That is, it can function as a λ / 4 plate. As the λ / 4 plate, for example, the fifth optical compensation layer can convert linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The fifth optical compensation layer can be formed of any appropriate material. Specifically, the same layer as the second optical compensation layer can be adopted.

I. Sixth Optical Compensation Layer The sixth optical compensation layer 17 has a refractive index ellipsoid 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 ₆ is less than 10 nm. The thickness direction retardation Rth ₆ of the sixth optical compensation layer can be set to any appropriate value. Preferably it is 25-300 nm, More preferably, it is 50-270 nm, Most preferably, it is 75-250 nm. The sixth optical compensation layer can be formed of any appropriate material. Specifically, the same layer as the third optical compensation layer can be adopted.

J. et al. Protective layer The said protective layer (a 1st protective layer, a 2nd protective layer, a 3rd protective layer, and a 4th protective layer) is formed with arbitrary appropriate films which can be used as a protective film of a polarizing plate. Specific examples of the material as 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 a 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., most preferably. Is 140 ° C. or higher. 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 that, a solution in which norbornene resin, acrylic resin, etc. are dissolved in a solvent such as cyclopentanone, methyl ethyl ketone, etc. 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, acetyltriethyl citrate to the fatty acid-substituted cellulose polymer, the thickness direction retardation (Rth) can be controlled to be 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.

K. Method for Manufacturing Liquid Crystal Panel The liquid crystal panel can be manufactured by any appropriate method. As a specific example, there is a method of sequentially laminating the above constituent elements (first to sixth optical compensation layers, first and second polarizers, etc.) on the liquid crystal cell. As another specific example, a first laminated optical film is manufactured by laminating a first polarizer, a first optical compensation layer, a second optical compensation layer, and a third optical compensation layer. The polarizer, the fourth optical compensation layer, the fifth optical compensation layer, and the sixth optical compensation layer are laminated to produce a second laminated optical film, and then the first laminated optical film and the second laminated optical film The laminated optical film is bonded to a liquid crystal cell.

  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). As the said adhesive layer, an acrylic adhesive layer is mentioned typically. The thickness of the acrylic pressure-sensitive adhesive layer provided on both sides of the liquid crystal cell is preferably 1 to 100 μm, more preferably 1 to 50 μm, and still more preferably 3 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.

  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) Contrast measurement 1
Computer simulations were performed on the liquid crystal panels of the examples and comparative examples using the optical characteristic parameters of the optical compensation layers actually fabricated and measured. For the simulation, a simulator for liquid crystal display “LCD MASTER” manufactured by Shintech Co., Ltd. was used.
(3) Contrast measurement 2
A white image and a black image were displayed on the liquid crystal display device, and measurement was performed using a product name “EZ Contrast 160D” manufactured by ELDIM.

[Example 1]
(Preparation of polarizing plate)
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) as a protective layer (first protective layer and second protective layer) is coated on each surface of the polarizer with a polyvinyl alcohol adhesive ( A thickness of 0.1 μm) was applied. 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.

(Preparation of the first 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. This film had a thickness of 35 μm, an in-plane retardation Re ₁ of 140 nm, and a thickness direction retardation Rth ₁ of 140 nm. The obtained film was punched into a size corresponding to a liquid crystal cell described later to obtain a first optical compensation layer.

(Preparation of second optical compensation layer)
The same film as the first optical compensation layer was used.

(Preparation of 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 3 μm, the thickness direction retardation Rth ₃ was 120 nm, and the in-plane retardation Re ₃ was substantially zero.

(Fabrication of the fourth optical compensation layer)
20 parts by weight of a side-chain liquid crystal polymer represented by the following chemical formula (3) (numbers 65 and 35 in the formula indicate mol% of the monomer units and are represented by block polymer for convenience: weight average molecular weight 5000), Dissolve 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name: Palicolor LC242) and 5 parts by weight of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Specialty Chemicals) in 200 parts by weight of cyclopentanone. Thus, a liquid crystal coating solution was prepared. And after apply | coating the said coating liquid to a base film (norbornene-type resin film: Nippon Zeon Co., Ltd. brand name Zeonor) with the bar coater, the liquid crystal was orientated by heating and drying at 80 degreeC for 4 minutes. By irradiating the liquid crystal layer with ultraviolet rays and curing the liquid crystal layer, a liquid crystal solidified layer serving as a fourth optical compensation layer was formed on the substrate. The in-plane retardation of this layer was substantially zero, and the thickness direction retardation Rth ₄ was −140 nm.

(Production of fifth optical compensation layer)
The same film as the first optical compensation layer was used.

(Fabrication of sixth optical compensation layer)
The same cholesteric alignment solidified layer as the third optical compensation layer was used.

(Preparation of 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, the laminate 1 in which the cholesteric alignment solidified layer is transferred to the second optical compensation layer is obtained.
On the second optical compensation layer side of the laminate 1, the first optical compensation layer and the polarizing plate are 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 orthogonal to the absorption axis of the polarizer of the polarizing plate, and the slow axis of the second optical compensation layer is absorbed by the polarizer of the polarizing plate. Lamination is performed so that the angle is 45 ° clockwise with respect to the axis. In this way, the laminated film A is produced.

(Preparation of laminated film B)
A liquid crystal solidified layer to be the fourth optical compensation layer was adhered to the fifth optical compensation layer obtained above with an isocyanate-based adhesive (thickness 5 μm), and the substrate (norbornene-based resin film) was removed. Then, the laminate 2 in which the fourth optical compensation layer is transferred to the fifth optical compensation layer is obtained. A cholesteric alignment solidified layer serving as a sixth optical compensation layer is adhered to the laminate 2 on the fifth optical compensation layer side with an isocyanate-based adhesive (thickness: 5 μm), and the substrate (biaxially stretched PET film) is removed. Thus, the laminate 3 in which the cholesteric alignment solidified layer is transferred to the fifth optical compensation layer side of the laminate 2 is obtained.
A polarizing plate is laminated on the fourth optical compensation layer side of the laminate 3 with an acrylic pressure-sensitive adhesive (thickness: 12 μm). At this time, the fifth optical compensation layer is laminated so that the slow axis is 45 ° clockwise with respect to the absorption axis of the polarizer of the polarizing plate. In this way, the laminated film B is produced.

(Production of liquid crystal panel)
A liquid crystal cell is removed from a Sony PlayStation Portable (VA mode liquid crystal cell mounted), and the laminated film A is attached to the backlight side of the liquid crystal cell via an acrylic adhesive (thickness 20 μm). At this time, the third optical compensation layer is attached so as to be on the liquid crystal cell side. Moreover, the said laminated | multilayer film B is affixed on the visual recognition side of a liquid crystal cell through an acrylic adhesive (thickness 20 micrometers). At this time, the sixth optical compensation layer is attached so as to be on the liquid crystal cell side. Moreover, it laminates | stacks 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 may mutually cross substantially orthogonally. Specifically, the retardation axis of the first optical compensation layer is 90 ° counterclockwise with the absorption axis of the polarizer on the backlight side as a reference (0 °), and the slow phase of the second optical compensation layer Lamination is performed so that the axis is 45 °, the slow axis of the fifth optical compensation layer is 135 °, and the absorption axis of the polarizer on the viewing side is 90 °. In this way, a liquid crystal panel is produced.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using such a liquid crystal panel. The results are shown in FIG.

[Example 2]
A liquid crystal panel is obtained in the same manner as in Example 1 except that the laminated film A is laminated on the viewing side of the liquid crystal cell and the laminated film B is laminated on the backlight side of the liquid crystal cell. The slow axis of the fifth optical compensation layer is 45 ° and the slow axis of the second optical compensation layer is 135 counterclockwise with the absorption axis of the polarizer on the backlight side as a reference (0 °). The layers are laminated so that the slow axis of the first optical compensation layer is 0 ° and the absorption axis of the polarizer on the viewing side is 90 °.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using such a liquid crystal panel. The results are shown in FIG.

[Example 3]
(Preparation of laminated film C)
A laminated film C is produced in the same manner as the laminated optical film A, except that lamination is performed so that the slow axis of the first optical compensation layer is parallel to the absorption axis of the polarizer of the polarizing plate.

(Production of liquid crystal panel)
A liquid crystal panel is obtained in the same manner as in Example 1 except that the laminated film C is used instead of the laminated film A. Note that the slow axis of the first optical compensation layer is 45 ° counterclockwise, and the slow axis of the second optical compensation layer is 45 °, with the absorption axis of the polarizer on the backlight side as a reference (0 °). The layers are laminated so that the slow axis of the fifth optical compensation layer is 135 ° and the absorption axis of the viewing side polarizer is 90 °.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using such a liquid crystal panel. The results are shown in FIG.

[Example 4]
A liquid crystal panel is obtained in the same manner as in Example 3 except that the laminated film C is laminated on the viewing side of the liquid crystal cell and the laminated film B is laminated on the backlight side of the liquid crystal cell. The slow axis of the fifth optical compensation layer is 45 ° and the slow axis of the second optical compensation layer is 135 counterclockwise with the absorption axis of the polarizer on the backlight side as a reference (0 °). The layers are laminated so that the slow axis of the first optical compensation layer is 90 ° and the absorption axis of the polarizer on the viewing side is 90 °.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using such a liquid crystal panel. The results are shown in FIG.

[Comparative Example 1]
(Preparation of laminated film D)
A polarizing plate is laminated on the second optical compensation layer side of the laminate 1 via an acrylic pressure-sensitive adhesive (thickness: 12 μm). At this time, the layers are laminated so that the slow axis of the second optical compensation layer is 45 ° clockwise with respect to the absorption axis of the polarizer of the polarizing plate. In this way, a laminated film D is produced.

(Production of liquid crystal panel)
A liquid crystal panel is obtained in the same manner as in Example 1 except that the laminated film D is used instead of the laminated film A, and the laminated film D is used instead of the laminated film B. The slow axis of the second optical compensation layer on the backlight side is 45 ° counterclockwise with respect to the absorption axis of the polarizer on the backlight side as a reference (0 °), and the second optical compensation on the viewing side. The layers are laminated so that the slow axis of the layer is 135 ° and the absorption axis of the polarizer on the viewing side is 90 °.
Computer simulation was performed on the viewing angle dependence of contrast of a liquid crystal display device using such a liquid crystal panel. The results are shown in FIG.

  Table 1 summarizes the overall configuration of the panels of Examples 1 to 4 and Comparative Example 1. The angle (counterclockwise) when the absorption axis of the polarizer on the backlight side is 0 ° is also shown.

  As apparent from FIGS. 3 to 7, the liquid crystal panels of Examples 1 to 4 of the present invention were superior in contrast to the liquid crystal panel of Comparative Example 1. When Example 1 and Example 3, Example 2 and Example 4 are compared, the contrast is further improved by making the slow axis of the first optical compensation layer orthogonal to the absorption axis of the first polarizer. I understand that. 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 the result of the computer simulation about the viewing angle dependence of the contrast of the liquid crystal panel of Example 1 of this invention. It is the result of the computer simulation about the viewing angle dependence of the contrast of the liquid crystal panel of Example 2 of this invention. It is the result of the computer simulation about the viewing angle dependence of the contrast of the liquid crystal panel of Example 3 of this invention. It is the result of the computer simulation about the viewing angle dependence of the contrast of the liquid crystal panel of Example 4 of this invention. It is the result of the computer simulation about the viewing angle dependence of the contrast of the liquid crystal panel of the comparative example 1.

Explanation of symbols

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

Claims (5)

A VA mode liquid crystal cell;
A first polarizer disposed on one side of the liquid crystal cell;
A refractive index ellipsoid arranged in order from the first polarizer side between the liquid crystal cell and the first polarizer shows a relationship of nx> ny = nz, and an in-plane retardation Re ₁ is 80. A first optical compensation layer having a refractive index ellipsoid of nx> ny = nz, an in-plane retardation Re ₂ of 80-200 nm, and a refractive index ellipse. A third optical compensation layer whose body exhibits a relationship of nx = ny>nz;
A second polarizer disposed on the other side of the liquid crystal cell;
A fourth optical compensation layer disposed in order from the second polarizer side between the liquid crystal cell and the second polarizer, the refractive index ellipsoid showing a relationship of nz> nx = ny, a refractive index 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. And an optical compensation layer.   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 orthogonally. A liquid crystal panel according to any one of claims 1-4, a liquid crystal display device.