JP2008134546A - Multilayer optical film, liquid crystal panel using the multilayer optical film, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer optical film having excellent screen contrast and a reduced color shift. <P>SOLUTION: The multilayer optical film at least includes: a polarizer; a first optical compensation layer in which a refractive index ellipsoid exhibits the relation of nx>nz>ny and an in-plane phase difference Re<SB>1</SB>is 200 to 300 nm; a second optical compensation layer in which a refractive index ellipsoid exhibits the relation of nx>nz>ny and an in-plane phase difference Re<SB>2</SB>is 90 to 160 nm; and a third optical compensation layer in which a refractive index ellipsoid exhibits the relation of nx=ny>nz in this order, and an angle αformed by the absorption axis of the polarizer and the slow axis of the first optical compensation layer and an angle βformed by the absorption axis of the polarizer and the slow axis of the second optical compensation layer satisfy the following inequality (1) (2α+30°)<β<(2α+60°). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated optical film, a liquid crystal panel using the laminated optical film, and a liquid crystal display device. More specifically, the present invention relates to a laminated optical film having a polarizer and at least three optical compensation layers, a liquid crystal panel using the laminated optical film, and a liquid crystal display device.

  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 laminated optical film, a liquid crystal panel, and a liquid crystal display device that have excellent screen contrast and a small color shift. is there.

The laminated optical film of the present invention includes a polarizer, a first optical compensation layer having a refractive index ellipsoid of nx>nz> ny, an in-plane retardation Re ₁ of 200 to 300 nm, and a refractive index ellipse. A third optical compensation layer having a relationship of nx>nz> ny, an in-plane retardation Re ₂ of 90 to 160 nm, and a refractive index ellipsoid having a relationship of nx = ny> nz. At least in this order, an angle α formed by the absorption axis of the polarizer and the slow axis of the first optical compensation layer, the absorption axis of the polarizer and the second optical compensation layer The angle β formed by the slow axis satisfies the following formula (1).
(2α + 30 °) <β <(2α + 60 °) (1)

  In a preferred embodiment, an optical compensation layer in which a refractive index ellipsoid exhibits a relationship of nz> nx = ny is further provided between the polarizer and the first optical compensation layer.

  In a preferred embodiment, the refractive index ellipsoid shows a relationship of nx> ny> nz and the in-plane retardation Re is 80 to 300 nm between the polarizer and the first optical compensation layer. Further comprising a layer.

  In a preferred embodiment, the refractive index ellipsoid shows a relationship of nx> ny = nz and the in-plane retardation Re is 80 to 300 nm between the polarizer and the first optical compensation layer. Further comprising a layer.

  In a preferred embodiment, the refractive index ellipsoid shows a relationship of nx> nz> ny and the in-plane retardation Re is 80 to 300 nm between the polarizer and the first optical compensation layer. Further comprising a layer.

  According to another aspect of the present invention, a liquid crystal panel is provided. This liquid crystal panel has a liquid crystal cell and the laminated optical film.

  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.

  As described above, according to the present invention, by arranging the first optical compensation layer, the second optical compensation layer, and the third optical compensation layer having the above optical characteristics at a predetermined angle, the screen contrast And 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.

A. Laminated optical film A-1. 1 is a schematic cross-sectional view of a laminated optical film according to a preferred embodiment of the present invention. The laminated optical film 10 includes a polarizer 11, a first optical compensation layer 12, a second optical compensation layer 13, and a third optical compensation layer 14 in this order. Although not shown, a first protective layer is provided between the polarizer 11 and the first optical compensation layer 12 as necessary, and a second protective layer 12 is provided on the opposite side of the polarizer 11 from the first optical compensation layer 12. A protective layer is provided. FIG. 1B is a schematic cross-sectional view of a laminated optical film according to another preferred embodiment of the present invention. This laminated optical film 10 ′ includes a polarizer 11, a first optical compensation layer 12, a second optical compensation layer 13, and a third optical compensation layer 14 in this order. The laminated optical film 10 ′ further includes another optical compensation layer 15 between the polarizer 11 and the first optical compensation layer 12. The other optical compensation layer 15 may be a single layer or a laminate. Although not shown, a first protective layer is provided between the polarizer 11 and the other optical compensation layer 15 as necessary, and a second protection is provided on the opposite side of the other optical compensation layer 15 of the polarizer 11. A layer is provided.

  The first optical compensation layer 12 can function as a so-called λ / 2 plate. In this specification, “λ / 2 plate” refers to converting linearly polarized light having a specific vibration direction into linearly polarized light having a vibration direction orthogonal to the vibration direction of the linearly polarized light, or converting right circularly polarized light. It has a function of converting left circularly polarized light (or converting left circularly polarized light into right circularly polarized light). The second optical compensation layer 13 can function as a so-called λ / 4 plate. In this specification, “λ / 4 plate” refers to a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light).

  FIG. 2 is an exploded perspective view for explaining the optical axis of each layer constituting the laminated optical films 10 and 10 ′ shown in FIG. 1 (other optical compensation layers 15 in the laminated optical film 10 ′ are not shown). The first optical compensation layer 12 is laminated such that the slow axis B defines a predetermined angle α with respect to the absorption axis A of the polarizer 11. The second optical compensation layer 13 is laminated such that the slow axis C defines a predetermined angle β with respect to the absorption axis A of the polarizer 11.

The angle α and the angle β have the relationship of the following formula (1):
(2α + 30 °) <β <(2α + 60 °) (1).
The relationship between the angle α and the angle β is preferably (2α + 35 °) <β <(2α + 55 °), more preferably (2α + 40 °) <β <(2α + 50 °), and particularly preferably β = 2α + 45 °.

  The angle α is preferably 8 to 22 °, more preferably 10 to 20 °, and particularly preferably 12 to 18 °. Therefore, in a particularly preferred embodiment (β = 2α + 45 °), the angle β is preferably 61-89 °, more preferably 65-85 °, particularly preferably 69-81 °. In FIG. 2, the angles α and β are defined in a counterclockwise direction with respect to the absorption axis A, but may be defined in a clockwise direction.

  In the laminated optical film shown in FIG. 1B, when the in-plane retardation of the other optical compensation layer 15 is larger than 0, the slow axis of the other optical compensation layer 15 is the absorption axis A of the polarizer 11. On the other hand, it is preferably laminated so as to be substantially parallel or orthogonal. In this specification, “substantially parallel” includes a case of 0 ° ± 3.0 °, preferably 0 ° ± 1.0 °, more preferably 0 ° ± 0.5 °. . “Substantially orthogonal” includes the case of 90 ° ± 3.0 °, preferably 90 ° ± 1.0 °, and more preferably 90 ° ± 0.5 °.

  The total thickness of the laminated optical film of the present invention is preferably 250 to 410 μm, more preferably 255 to 405 μm, and particularly preferably 260 to 400 μm. Hereinafter, the detail of each layer which comprises the laminated optical film of this invention is demonstrated.

A-2. First Optical Compensation Layer As described above, the first optical compensation layer 12 can function as a so-called λ / 2 plate. With the first optical compensation layer functioning as a λ / 2 plate, the wavelength dispersion characteristics of the second optical compensation layer functioning as a λ / 4 plate (particularly the wavelength range where the phase difference deviates from λ / 4), The phase difference can be adjusted appropriately. The first optical compensation layer has a refractive index ellipsoid of nx>nz> ny. The in-plane retardation Re ₁ of the first optical compensation layer is 200 to 300 nm, preferably 230 to 290 nm, and more preferably 260 to 280 nm. The Nz coefficient (Rth ₁ / Re ₁ ) is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, and particularly preferably 0.3 to 0.7.

  The thickness of the first optical compensation layer can be set so as to function most appropriately as a λ / 2 plate. In other words, the thickness can be set so as to obtain desired optical characteristics. Preferably it is 30-100 micrometers, More preferably, it is 40-90 micrometers, Most preferably, it is 50-80 micrometers.

  The first optical compensation layer can be formed of any appropriate material as long as the above characteristics are obtained. A typical example is a stretched polymer film. The resin forming the polymer film is preferably a norbornene resin or a polycarbonate resin.

  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.

  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 the said stretched film. A typical example is a method in which a shrinkable film is bonded to one side or both sides of the polymer film, followed by heat stretching. The shrinkable film is used for imparting a shrinkage force in a direction orthogonal to the stretching direction during heat stretching. Examples of the material used for the shrinkable film include polyester, polystyrene, polyethylene, polypropylene, polyvinyl chloride, and polyvinylidene chloride. From the viewpoint of excellent shrinkage uniformity and heat resistance, a polypropylene film is preferably used.

  As the stretching method, any appropriate stretching method can be adopted as long as the tension in the stretching direction of the polymer film and the shrinkage force in the direction orthogonal to the stretching direction in the film plane can be imparted. . The stretching temperature is preferably equal to or higher than the glass transition temperature (Tg) of the polymer film. This is because the retardation value of the obtained stretched film is likely to be uniform, and the film is difficult to crystallize (white turbidity). The stretching temperature is more preferably Tg + 1 ° C. to Tg + 30 ° C., more preferably Tg + 2 ° C. to Tg + 20 ° C., particularly preferably Tg + 3 ° C. to Tg + 15 ° C., and most preferably Tg + 5 ° C. to Tg + 10 ° C. By setting the stretching temperature in such a range, uniform heating and stretching can be performed. Furthermore, the stretching temperature is preferably constant in the film width direction. This is because a stretched film having good optical uniformity with small variations in retardation value can be produced.

  The draw ratio at the time of drawing may be set to any appropriate value. It is preferably 1.05 to 2.00 times, more preferably 1.10 to 1.50 times, particularly preferably 1.20 to 1.40 times, and most preferably 1.25 to 1.30 times. By setting the draw ratio in such a range, a stretched film having little mechanical shrinkage and excellent mechanical strength can be obtained.

A-3. Second Optical Compensation Layer As described above, the second optical compensation layer 13 can function as a so-called λ / 4 plate. According to the present invention, the wavelength dispersion characteristic of the second optical compensation layer functioning as a λ / 4 plate is corrected by the optical characteristic of the first optical compensation layer functioning as the λ / 2 plate, thereby obtaining a wide wavelength range. The circular polarization function in a range can be exhibited. The second optical compensation layer has a refractive index ellipsoid of nx>nz> ny. The in-plane retardation Re ₂ of the second optical compensation layer is 90 to 160 nm, preferably 110 to 155 nm, and more preferably 130 to 150 nm. The Nz coefficient (Rth ₂ / Re ₂ ) is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, and particularly preferably 0.3 to 0.7.

  The thickness of the second optical compensation layer 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. Preferably it is 20-90 micrometers, More preferably, it is 30-80 micrometers, Most preferably, it is 40-70 micrometers.

  The second optical compensation layer can be formed of any appropriate material as long as the above characteristics are obtained. A representative example is the stretched polymer film described in Section A-2. As the stretching conditions for the stretched film, any appropriate conditions can be adopted as long as the optical characteristics are obtained. The draw ratio during stretching is preferably 1.00 to 2.00 times, more preferably 1.01 to 1.50 times, particularly preferably 1.05 to 1.20 times, and most preferably 1.07 to 1. .13 times.

A-4. 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 Rth3 of the _third optical compensation layer can be set to any appropriate value depending on the configuration of the applied liquid crystal panel. Although details will be described later in section B, when the third optical compensation layer is disposed only on one side of the liquid crystal cell, the thickness direction retardation Rth ₃ is preferably 50 to 600 nm, more preferably Is 100 to 540 nm, particularly preferably 150 to 500 nm. On the other hand, when the third optical compensation layer is disposed on both sides of the liquid crystal cell, the thickness direction retardation Rth ₃ is preferably 25 to 300 nm, more preferably 50 to 270 nm, and particularly preferably 75 to 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.

A-5. Other Optical Compensation Layer The laminated optical film of the present invention may further include an optical compensation layer exhibiting any appropriate optical characteristics. For example, as described above, another optical compensation layer 15 may be provided between the polarizer and the first optical compensation layer. The other optical compensation layer 15 may be a single layer or a laminate. Hereinafter, representative examples will be described.

A-5-1. Positive C plate The other optical compensation layer 15 may exhibit a refractive index ellipsoid of nz> nx = ny in one embodiment. Such an optical compensation layer (retardation film) is referred to as a positive C plate (hereinafter sometimes abbreviated as PC for convenience). In this case, the thickness direction retardation Rth 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 is less than 10 nm.

  The optical compensation layer exhibiting a refractive index ellipsoid of nz> nx = ny 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 [0028] and the method for forming the film. In this case, the thickness is preferably 0.5 to 10 μm, more preferably 0.5 to 8 μm, and particularly preferably 0.5 to 5 μm.

A-5-2.2 Axis Retardation Film The other optical compensation layer 15 may exhibit a refractive index ellipsoid of nx>ny> nz in another embodiment. In this case, the in-plane retardation Re is preferably 80 to 300 nm. The Nz coefficient preferably shows a relationship of 1 <Nz <2, more preferably 1 <Nz <1.5.

  The optical compensation layer exhibiting a refractive index ellipsoid of nx> ny> nz 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 A-2. Arbitrary appropriate methods can be employ | adopted as a preparation method of a stretched film. Examples of the stretching method include lateral uniaxial stretching (fixed end biaxial stretching) and sequential biaxial stretching. The stretching temperature is preferably 135 to 165 ° C, more preferably 140 to 160 ° C. The draw ratio is preferably 2.8 to 3.2 times, more preferably 2.9 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 the material for forming the optical compensation layer exhibiting a refractive index ellipsoid of nx> ny> nz is a non-liquid crystalline material. A non-liquid crystalline polymer is preferable. 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 optical compensation layer can be typically formed by applying a solution of the non-liquid crystal 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. 2006-234848 are mentioned. In this case, the thickness is typically 0.1 to 10 μm, more preferably 0.1 to 8 μm, and particularly preferably 0.1 to 5 μm.

A-5-3. Positive A plate The other optical compensation layer 15 may exhibit a refractive index ellipsoid of nx> ny = nz in yet another embodiment. Such an optical compensation layer (retardation film) is referred to as a positive A plate (hereinafter sometimes abbreviated as PA for convenience). In this case, the in-plane retardation Re is preferably 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 ₄ / Re ₄ ) is more than 0.9 and less than 1.1.

  The optical compensation layer showing a refractive index ellipsoid of nx> ny = nz 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. Therefore, in the formed 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 optical compensation layer is extremely stable and is not affected by temperature changes.

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

  When the 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.

  An optical compensation layer showing a refractive index ellipsoid of nx> ny = nz 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, and the like, 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. Details of these resins are as described above in section A-2.

A-5-4. Z film The other optical compensation layer 15 may exhibit a refractive index ellipsoid of nx>nz> ny in still another embodiment. Such a biaxial optical compensation layer (retardation film) is particularly referred to as a Z film. In this case, the in-plane retardation Re is preferably 80 to 300 nm. The Nz coefficient (Rth / Re) is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, and particularly preferably 0.3 to 0.7.

  The optical compensation layer exhibiting a refractive index ellipsoid of nx> nz> ny can be formed of any appropriate material. Specific examples include the stretched polymer film described in the above sections A-2 and A-3. That is, when the stretched film can function as a λ / 2 plate, the thickness is preferably 30 to 100 μm, more preferably 40 to 90 μm, and particularly preferably 50 to 80 μm. The stretch ratio of the stretched film is preferably 1.05 to 2.00 times, more preferably 1.10 to 1.50 times, particularly preferably 1.20 to 1.40 times, most preferably 1.25 to 1.30 times. On the other hand, when the stretched film can function as a λ / 4 plate, the thickness is preferably 20 to 90 μm, more preferably 30 to 80 μm, and particularly preferably 40 to 70 μm. The stretch ratio of the stretched film is preferably 1.00 to 2.00 times, more preferably 1.01 to 1.50 times, particularly preferably 1.05 to 1.20 times, and most preferably 1.07 to 1.13 times.

A-5-5. Positive C plate + biaxial retardation film In another embodiment, the other optical compensation layer 15 includes a layer (positive C plate) showing a refractive index ellipsoid of nz> nx = ny, and nx>ny>. The refractive index ellipsoid of nz may be shown, and it may be a laminate with a layer having an in-plane retardation Re of 80 to 300 nm. The positive C plate is as described in A-5-1. The layer showing the refractive index ellipsoid of nx>ny> nz is as described in A-5-2.

A-5-6. Positive C plate + Positive A plate In another embodiment, the other optical compensation layer 15 includes a layer showing a refractive index ellipsoid of nz> nx = ny (positive C plate), and nx> ny = nz. A refractive index ellipsoid, which may be a laminate with a layer (positive A plate) having an in-plane retardation Re of 80 to 300 nm. The details of the positive C plate are as described in A-5-1. The details of the positive A plate are as described in A-5-3.

A-6. Polarizer Any appropriate polarizer may be employed as the polarizer 11 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.

A-7. Protective layer The first protective layer and the second protective layer are formed of any appropriate film that can be used as a protective film for 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. The upper limit value of Tg of the (meth) acrylic resin is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like.

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 protective layer and the second protective layer are preferably transparent and have no color. The thickness direction retardation Rth of the second protective layer is preferably −90 nm to +90 nm, more preferably −80 nm to +80 nm, and particularly preferably −70 nm to +70 nm.

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

  On the opposite side of the second protective layer 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 polarizer and the optical compensation layer preferably has a smaller thickness direction retardation (Rth) than the second protective layer. 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. Therefore, the first protective layer can be suitably obtained by subjecting the cellulose-based film having a large thickness direction retardation (Rth) to appropriate treatment for reducing the thickness direction retardation (Rth). .

  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 protective layer obtained by such treatment is preferably −20 nm to +20 nm, more preferably −10 nm to +10 nm, particularly preferably −6 nm to +6 nm, and most preferably Preferably, it is −3 nm to +3 nm. The in-plane retardation Re (550) of the first protective layer is preferably 0 nm or more and 10 nm or less, more preferably 0 nm or more and 6 nm or less, and particularly preferably 0 nm or more and 3 nm or less.

  The thickness of the first protective layer is preferably 20 to 200 μm, more preferably 30 to 100 μm, and still more preferably 35 to 95 μm.

A-8. Lamination method Arbitrary appropriate methods can be employ | adopted for the lamination | stacking method of said each layer (film). Specifically, it is laminated via any appropriate pressure-sensitive adhesive layer or adhesive layer. As the said adhesive layer, an acrylic adhesive layer is mentioned typically. The thickness of the acrylic pressure-sensitive adhesive layer is preferably 1 to 20 μm, more preferably 5 to 12 μm.

B. Liquid crystal panel B-1. Overall Configuration of Liquid Crystal Panel FIG. 3A is a schematic cross-sectional view of a liquid crystal panel according to one embodiment of the present invention. The liquid crystal panel 100 includes a liquid crystal cell 20; the laminated optical film 10 of the present invention disposed on one side of the liquid crystal cell 20 (backlight side in the illustrated example); and one side of the liquid crystal cell 20 (in the illustrated example). And a laminated film 30 disposed on the viewing side. The laminated film 30 includes the polarizer 11, the first optical compensation layer 12, and the second optical compensation layer 13 in this order. Although not shown, the laminated film 30 may further include any appropriate other optical compensation layer between the polarizer 11 and the first optical compensation layer 12, for example. In addition, the laminated film 30 is provided with a first protective layer between the polarizer 11 and the first optical compensation layer 12 as necessary, and the opposite side of the polarizer 11 from the first optical compensation layer 12. Is provided with a second protective layer. As illustrated, the laminated optical film 10 and the laminated film 30 are arranged so that the side on which the optical compensation layer is provided is the liquid crystal cell 20 side. Unlike the illustrated example, the laminated optical film 10 may be arranged on the viewing side, and the laminated film 30 may be arranged on the backlight side.

  FIG. 3B is a schematic cross-sectional view of a liquid crystal panel according to another embodiment of the present invention. The liquid crystal panel 100 ′ includes a liquid crystal cell 20; the laminated optical film 10 ′ of the present invention disposed on one side of the liquid crystal cell 20 (the backlight side in the illustrated example); and one side of the liquid crystal cell 20 (FIG. And a laminated film 30 disposed on the viewing side in the illustrated example. As shown in the figure, the laminated optical film 10 ′ and the laminated film 30 are arranged so that the side on which the optical compensation layer is provided is the liquid crystal cell 20 side. FIG. 3C is a schematic cross-sectional view of a liquid crystal panel according to still another embodiment of the present invention. The liquid crystal panel 100 ″ includes a liquid crystal cell 20; a laminated optical film 10 ′ of the present invention disposed on one side of the liquid crystal cell 20 (the backlight side in the illustrated example); and one side of the liquid crystal cell 20 (see FIG. The laminated optical film 10 of the present invention is disposed on the viewing side in the illustrated example.As shown in the drawing, the laminated optical films 10 and 10 'are respectively provided with the optical compensation layer on the liquid crystal cell 20 side. It is arranged to be.

FIG. 4 is an exploded perspective view for explaining the optical axis of each layer constituting the laminated film 30 constituting the liquid crystal panels 100 and 100 ′ shown in FIGS. 3 (a) and 3 (b). The first optical compensation layer 12 is laminated so that the slow axis B defines a predetermined angle α with respect to the absorption axis A of the polarizer 11. The second optical compensation layer 13 is laminated such that the slow axis C defines a predetermined angle β with respect to the absorption axis A of the polarizer 11. The angles α and β preferably satisfy the following formula (1):
(2α + 30 °) <β <(2α + 60 °) (1).
The relationship between the angle α and the angle β is preferably (2α + 35 °) <β <(2α + 55 °), more preferably (2α + 40 °) <β <(2α + 50 °), and particularly preferably β = 2α + 45 °.

  The angle α is preferably 8 to 22 °, more preferably 10 to 20 °, and particularly preferably 12 to 18 °. Therefore, in a particularly preferred embodiment (β = 2α + 45 °), the angle β is preferably 61-89 °, more preferably 65-85 °, particularly preferably 69-81 °. In FIG. 4, the angles α and β are defined in a counterclockwise direction with respect to the absorption axis A, but may be defined in a clockwise direction.

  The absorption axes of the polarizers 11 and 11 disposed on both sides of the liquid crystal cell 20 of the liquid crystal panels 100, 100 ', and 100 "are preferably disposed so as to be substantially orthogonal.

B-2. 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. 5 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in FIG. 5A, 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, linearly polarized light that has passed through one polarizer 11 and entered the liquid crystal layer 22 has a long axis of liquid crystal molecules that are vertically aligned. Proceed along the direction. Since birefringence does not occur in the major axis direction of the liquid crystal molecules, incident light travels without changing the polarization direction and is absorbed by the other polarizer 11 having a polarization axis orthogonal to one polarizer 11. This provides a dark display when no voltage is applied (normally black mode). As shown in FIG. 5B, when a voltage is applied between the electrodes, the long axes of the liquid crystal molecules are 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 one polarizer 11 and entered the liquid crystal layer 22, and the polarization state of the incident light changes in accordance with the inclination of the liquid crystal molecules. . The light passing 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 thus the light is transmitted through the other polarizer 11 to obtain a bright display. When the voltage is not applied again, the display can be returned to the dark state by the orientation regulating force. In addition, gradation display is possible by changing the applied voltage to control the inclination of the liquid crystal molecules to change the transmitted light intensity from the other polarizer 11.

B-3. Regarding the thickness direction retardation of the third optical compensation layer As shown in FIGS. 3A and 3B, when the third optical compensation layer 14 is disposed only on one side of the liquid crystal cell 20, retardation Rth ₃ in the thickness direction of the third optical compensation layer is preferably 50 to 600 nm, more preferably 100～540Nm, particularly preferably 150 to 500 nm. On the other hand, as shown in FIG. 3C, when the third optical compensation layer 14 is disposed on both sides of the liquid crystal cell 20, the thickness direction retardation Rth ₃ of each third optical compensation layer is: Preferably, it is substantially half of the retardation in the thickness direction when it is arranged on one side. That is, it is preferably 25 to 300 nm, more preferably 50 to 270 nm, and particularly preferably 75 to 250 nm.

B-4. Lamination method Arbitrary appropriate methods can be employ | adopted for the lamination | stacking method of said each layer (film). Specifically, it is laminated via any appropriate pressure-sensitive adhesive layer or adhesive layer.

  The laminated optical film, liquid crystal panel, and liquid crystal display device of the present invention can be suitably applied to mobile phones, liquid crystal televisions, and the like.

(A) is a schematic sectional drawing of the laminated optical film by preferable embodiment of this invention, (b) is a schematic sectional drawing of the laminated optical film by another preferable embodiment of this invention. It is a disassembled perspective view explaining the optical axis of each layer which comprises the laminated optical film by preferable embodiment of this invention. (A) is a schematic cross-sectional view of a liquid crystal panel according to one embodiment of the present invention, (b) is a schematic cross-sectional view of a liquid crystal panel according to another preferred embodiment of the present invention, (c) is It is a schematic sectional drawing of the liquid crystal panel by another preferable embodiment of this invention. It is a disassembled perspective view explaining the optical axis of each layer which comprises the laminated | multilayer film which comprises the liquid crystal panel shown to Fig.3 (a). 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laminated optical film 10 'Laminated optical film 11 Polarizer 12 1st optical compensation layer 13 2nd optical compensation layer 14 3rd optical compensation layer 15 Other optical compensation layer 20 Liquid crystal cell 100 Liquid crystal panel 100' Liquid crystal panel 100 ”LCD panel

Claims (8)

A polarizer,
A refractive index ellipsoid showing a relationship of nx>nz> ny, an in-plane retardation Re ₁ of 200 to 300 nm,
A refractive index ellipsoid showing a relationship of nx>nz> ny, an in-plane retardation Re ₂ of 90 to 160 nm,
A refractive index ellipsoid and a third optical compensation layer exhibiting a relationship of nx = ny> nz, at least in this order,
An angle α formed between the absorption axis of the polarizer and the slow axis of the first optical compensation layer, and an angle β formed between the absorption axis of the polarizer and the slow axis of the second optical compensation layer. A laminated optical film that satisfies the following formula (1).
(2α + 30 °) <β <(2α + 60 °) (1)   The laminated optical film according to claim 1, further comprising an optical compensation layer having a refractive index ellipsoid showing a relationship of nz> nx = ny between the polarizer and the first optical compensation layer.   An optical compensation layer having a refractive index ellipsoid of nx> ny> nz and an in-plane retardation Re of 80 to 300 nm is further provided between the polarizer and the first optical compensation layer. Item 2. The laminated optical film according to Item 1.   An optical compensation layer having a refractive index ellipsoid of nx> ny = nz and an in-plane retardation Re of 80 to 300 nm is further provided between the polarizer and the first optical compensation layer. Item 2. The laminated optical film according to Item 1.   An optical compensation layer having a refractive index ellipsoid of nx> nz> ny and an in-plane retardation Re of 80 to 300 nm is further provided between the polarizer and the first optical compensation layer. Item 2. The laminated optical film according to Item 1.   A liquid crystal panel having a liquid crystal cell and the laminated optical film according to claim 1.   The liquid crystal panel according to claim 6, wherein the liquid crystal cell is in a VA mode.   A liquid crystal display device comprising the liquid crystal panel according to claim 6.

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