WO2008062624A1

WO2008062624A1 - Multilayer optical film, liquid crystal panel employing multilayer optical film and liquid crystal display

Info

Publication number: WO2008062624A1
Application number: PCT/JP2007/070585
Authority: WO
Inventors: Masato Bitou; Shunsuke Shutou; Misaki Sabae; Ikuo Kawamoto; Hironori Motomura
Original assignee: Nitto Denko Corporation
Priority date: 2006-11-20
Filing date: 2007-10-23
Publication date: 2008-05-29
Also published as: KR20090073235A

Abstract

A multilayer optical film exhibiting excellent screen contrast while suppressing color shift. A liquid crystal panel and a liquid crystal display are also provided. The multilayer optical film comprises at least a polarizer, a first optical compensation layer where an index ellipsoid has a relation of nx>ny=nz and the in-plane retardation Re1 is 80-300 nm, a second optical compensation layer where an index ellipsoid has a relation of nz>nx=ny, and a third optical compensation layer where an index ellipsoid has a relation of nx>ny=nz and the in-plane retardation Re3 is 80-200 nm formed in this order, and the absorption axis of the polarizer intersects the slow axis of the first optical compensation layer perpendicularly.

Description

Specification

LAMINATED OPTICAL FILM, LIQUID CRYSTAL PANEL AND LIQUID CRYSTAL DISPLAY DEVICE USING LAMINATED OPTICAL FILM

Technical field

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.

Background art

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

[0003] A circularly polarizing plate, which is a kind of the optical film, can usually be produced by combining a polarizing film and a λ / 4 plate. The λ / 4 plate exhibits a characteristic that the phase difference value increases as the wavelength becomes shorter, that is, a so-called “positive wavelength dispersion characteristic”, and has a large wavelength dispersion characteristic. Is common. For this reason, there is a problem that the 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 retardation 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 Finolems are problematic 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, A method of correcting the wavelength dispersion characteristics of the above-mentioned / 4 plate is adopted (for example, see Patent Document 1). However, these technologies do not improve the screen contrast and reduce the color shift, and the shift is insufficient.

Patent Document 1: Japanese Patent No. 3174367

Disclosure of the invention Problems to be solved by the invention

[0005] The present invention has been made to solve the above-described conventional problems. The object of the present invention is to provide a laminated optical film, a liquid crystal panel, and a liquid crystal display device having excellent screen contrast and small color shift. Is to provide.

Means for solving the problem

The laminated optical film of the present invention has a relationship between a polarizer and a refractive index ellipsoidal force ¾x> ny = nz, an in-plane retardation Re of 80 to 300 nm, and a refractive index. The second optical compensation layer in which the ellipsoid shows a relationship of nz> nx = ny (7) and the refractive index ellipsoid shows the relationship of nx> ny = nz, and the in-plane retardation Re is 80 to 200 nm. 3 optical compensation layers and at least this

Three

In order, the absorption axis of the polarizer and the slow axis of the first optical compensation layer are orthogonal to each other.

[0007] In another embodiment, the laminated optical film of the present invention is a first in which the polarizer and the refractive index ellipsoid have a relationship of nx>ny> nz and have an in-plane retardation Re force S80 to 300 nm. The optical compensation layer, the second ellipsoid whose refractive index ellipsoid shows a relationship of nz> _nx = ny, and the refractive index ellipsoidal force ¾ix> shows the relationship of nv = nz, and the in-plane retardation Re force S80 ~ The third is 200nm

Three

The optical compensation layer is provided at least in this order, and the absorption axis of the polarizer and the slow axis of the first optical compensation layer are orthogonal to each other.

In a preferred embodiment, the fourth optical element is disposed on the opposite side of the third optical compensation layer from the second optical compensation layer, and the refractive index ellipsoid shows a relationship of nx = ny> nz. A compensation layer is further provided.

[0009] According to another aspect of the present invention, a liquid crystal panel is provided. This liquid crystal panel includes a liquid crystal cell and the laminated optical film.

In a preferred embodiment, the laminated optical film is disposed on the backlight side.

In a preferred embodiment, a laminated finole comprising a polarizer and a fifth optical compensation layer whose refractive index ellipsoid shows a relationship of nx> ny = nz and has an in-plane retardation Re force of 0 to 200 nm.

Five

Is placed on the viewer side.

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

[0013] According to another aspect of the present invention, a liquid crystal display device is provided. This liquid crystal display device The liquid crystal panel is included.

The invention's effect

[0014] As described above, according to the present invention, the first optical compensation layer, the second optical compensation layer, and the third optical compensation layer having the above optical characteristics are arranged at a predetermined angle. Can improve screen contrast and reduce color shift.

Brief Description of Drawings

[Fig. L] (a) is a schematic cross-sectional view of a laminated optical film according to one embodiment of the present invention,

(b) is a schematic cross-sectional view of a laminated optical film according to another preferred embodiment of the present invention.

[FIG. 2] (a) is a schematic cross-sectional view of a liquid crystal panel according to one embodiment of the present invention, and (b) is a schematic cross-sectional view of a liquid crystal panel according to another preferred embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in a liquid crystal layer when the liquid crystal display device of the present invention employs a VA mode liquid crystal cell.

FIG. 4 is a result of computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Example 1 of the present invention.

FIG. 5 is a contrast contour map showing the viewing angle dependence of contrast of the liquid crystal panel of Example 1 of the present invention.

FIG. 6 shows the result of computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Example 2 of the present invention.

FIG. 7 is a contrast contour map showing the viewing angle dependence of the contrast of the liquid crystal panel of Example 2 of the present invention.

FIG. 8 is a result of computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Example 3 of the present invention.

FIG. 9 is a contrast contour map showing the viewing angle dependence of the contrast of the liquid crystal panel of Example 3 of the present invention.

FIG. 10 shows the result of a computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 1.

[FIG. 11] Contrast contour lines showing the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 1 FIG.

FIG. 12 shows the result of a computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 2.

13] A contrast contour map showing the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 2.

FIG. 14 shows the result of a computer simulation on the viewing angle dependence of the contrast of the liquid crystal panel of Comparative Example 3.

Explanation of symbols

10 Laminated optical film

10. Laminated optical film

11 Polarizer

12 First optical compensation layer

13 Second optical compensation layer

14 Third optical compensation layer

15 Fourth optical compensation layer

20 LCD Senor

100 LCD panel

100 'LCD panel

BEST MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, the ability to describe preferred embodiments of the present invention The present invention is not limited to these embodiments.

[0018] (Definition of terms and symbols)

The definitions of terms and symbols in this specification are as follows.

(1) u folding rate (nx, ny, nz)

“Nx” is the refractive index in the direction where the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the refractive index in the direction perpendicular to the slow axis in the plane, “nz "Is the refractive index in the thickness direction.

(2) In-plane phase difference (Re) The in-plane retardation (Re) is the in-plane retardation value of a layer (film) at 23 ° C, unless otherwise specified, at a wavelength of 590 nm. Re is obtained by Re = (nx−ny) Xd, where d (nm) is the thickness of the layer (film). In this specification, Re (550) refers to the in-plane retardation of a layer (film) at a wavelength of 550 nm. In addition, the subscript “1” attached to the terms and symbols described in this 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, and the subscript “4” represents the fourth optical compensation layer. For example, Re represents the in-plane retardation of the first optical compensation layer.

(3) Thickness direction retardation (Rth)

Thickness direction retardation (Rth) is the thickness direction retardation value of a layer (film) at 23 ° C, unless otherwise specified, at a wavelength of 590 nm. Rth is obtained by Rth = (nx−nz) Xd, where d (nm) is the thickness of the layer (film). In the present specification, when Rth (550) is indicated, it means a retardation in a thickness direction of a 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 denoted by Rth.

(4) Nz coefficient

The Nz coefficient is determined 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 generates a half-wavelength optical path difference between linearly polarized light that vibrates in directions perpendicular to each other. It has a function. That is, it works so that the phase between the ordinary ray component and the extraordinary ray component is shifted 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 generates a 1/4 wavelength optical path difference between linearly polarized light that vibrates in directions perpendicular to each other. It has a function. In other words, it works so that the phase between the ordinary ray component and the extraordinary ray component is shifted by a quarter of a cycle, and converts circularly polarized light into plane polarized light or plane polarized light into circularly polarized light).

積層 .Laminated optical film A- l. Overall structure of laminated optical film

FIG. 1 (a) is a schematic 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. FIG. 1 (b) is a schematic cross-sectional view of a laminated optical film according to another 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. The laminated optical film 10 ′ further includes a fourth optical compensation layer 15. In the illustrated example, the fourth optical compensation layer 15 is disposed on the opposite side of the third optical compensation layer 14 from the second optical compensation layer 13. Although not shown in FIGS. 1 (a) and (b), a first protective layer is provided between the polarizer 11 and the first optical compensation layer 12 as necessary, and the first protective layer of the polarizer 11 is provided. A second protective layer is provided on the opposite side of the optical compensation layer 12. If the first protective layer is not provided, the first optical compensation layer 12 can also function as a protective layer for the polarizer 11. When the first optical compensation layer functions as a protective layer, it can contribute to thinning of the laminated optical film (liquid crystal panel). Moreover, the laminated optical film of the present invention may further include any appropriate optical compensation layer as necessary.

The first optical compensation layer 12 has a slow axis, and is laminated so that the slow axis is perpendicular to the absorption axis of the polarizer 11. In this specification, the term “orthogonal” includes a case where it is substantially orthogonal. Here, “substantially orthogonal” includes the case of 90 ° ± 3.0 °, preferably 90 ° ± 1.0 °, more preferably 90 ° ± 0.5 °. The third optical compensation layer 14 has a refractive index ellipsoid of n _X > ny = _nz . The slow axis of the third optical compensation layer 14 is laminated so as to define any appropriate angle with respect to the absorption axis of the polarizer 11. The angle is preferably 30 to 60 °, more preferably 35 to 55 °, particularly preferably 40 to 50 °, and most preferably 43 to 47 °.

[0021] The total thickness of the laminated optical film of the present invention is preferably 250 to 410 111, more preferably (255 to 405 mm 111, particularly preferably (260 to 400 mm). The details of each layer constituting the optical film will be described.

[0022] A— 2-1 — First optical compensation layer (1)

In one embodiment, the first optical compensation layer 12 has a refractive index of nx> ny = nz. It has an ellipsoid. 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 / Re) is more than 0.9 and less than 1.1. The in-plane retardation Re of the first optical compensation layer is 80 to 300 nm, preferably 80 to 200 nm, more preferably 100 to; 180 nm, and particularly preferably 120 to 160 nm. The first optical compensation layer can compensate the optical axis of the polarizer. As described above, by arranging the first optical compensation layer so that the slow axis thereof is perpendicular to the absorption axis of the polarizer, the screen contrast when viewed from an oblique direction can be improved. Thus, the ability to arrange the slow axis of the first optical compensation layer to be orthogonal to the absorption axis of the polarizer is one of the features of the present invention.

As the material for forming the first optical compensation layer exhibiting the refractive index ellipsoid of nx> ny = nz, any appropriate material can be adopted as long as the above characteristics are obtained. A liquid crystal material (nematic liquid crystal) in which the liquid crystal phase preferred by the liquid crystal material is a nematic phase is even more preferred. By using a liquid crystal material, the difference between nx and ny of the obtained optical compensation layer can be made much larger than that of a 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 liquid crystallinity 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.

[0024] 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 bridging the liquid crystalline monomer. After aligning the liquid crystal monomers, for example, if the liquid crystal monomers are polymerized or cross-linked, the alignment state can be fixed accordingly. Here, a polymer is formed by polymerization, and a force that forms a three-dimensional network structure by crosslinking, these are non-liquid crystalline. Therefore, in the formed first optical compensation layer, for example, transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar 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.

[0025] Specific examples of the method for forming the liquid crystal monomer and the first optical compensation layer include monomers and methods described in JP 2006-178389 A.

[0026] The thickness of the first optical compensation layer may be set so as to obtain desired optical characteristics.

When the first optical compensation layer is formed of a liquid crystal material, the thickness is preferably from 0.5 to; ίθπι, more preferably from 0.5 to 8〃111, particularly preferably from 0.5 to 5〃m. is there.

[0027] The first optical compensation layer exhibiting a refractive index ellipsoid of nx> ny = nz can also be formed by stretching a polymer film. Specifically, by appropriately selecting the type of polymer, stretching conditions (for example, stretching temperature, stretching ratio, stretching direction), stretching method, and the like, the desired optical properties (for example, refractive index ellipsoid, A first optical compensation layer having an in-plane retardation and a retardation in the thickness direction can be obtained. More specifically, the stretching temperature is preferably 110 to 170 ° C, more preferably 130 to 150 ° C. The draw ratio is preferably 1.37 to 1.67 times, more preferably 1.42 to; Examples of the stretching method include lateral uniaxial stretching.

[0028] When the first optical compensation layer is formed by stretching a polymer film, the thickness is preferably 5 to 70 111, more preferably 10 to 65 111, and particularly preferably 15 to 5. 60 μm.

[0029] Any appropriate polymer can be adopted as the resin for forming the polymer film. Specific examples include resins constituting a positive birefringent film such as norbornene-based resin, polycarbonate-based resin, cellulose-based resin, polybutyl alcohol-based resin, and polysulfone-based resin. Of these, norbornene resins and polycarbonate resins are preferable.

[0030] 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. Polarity of these halogens, etc. Group substituents; dicyclopentagen, 2, 3 dihydrodicyclopentagen, etc .; dimethanootatahydronaphthalene, alkyl and / or alkylidene substituents thereof, and polar group substituents such as halogen, such as 6-methyl-1, 4: 5, 8—Dimethanone 1, 4, 4a, 5, 6, 7, 8, 8a—Yet Kuta Hydronaphthalene, 6—Ethenole 1, 4: 5, 8—Dimethanone 1, 4, 4a, 5, 6, 7, 8, 8a--aged Kutahydronaphthalene, 6-ethylidene 1, 4: 5, 8--dimethanone 1, 4, 4a, 5, 6, 7, 8, 8a-aged Kutahydronaphthalene, 6-chloro-1,4: 5 , 8 Dimethanone 1,4,4a, 5,6,7,8 8a-year-old Kutahydronaphthalene, 6-cyanol 1, 4: 5,8-dimethanone 1,4,4a, 5, 6, 7, 8, 8a—Talented Kutahydronaphthalene, 6—Pyridinole 1, 4: 5, 8—Dimethane 1,4,4a, 5, 6, 7, 8, 8a—Talented Kutahydronaphthalene, 6—Methoxycanoleponinole 1 , 4: 5, 8— Metanol 1, 4, 4a, 5, 6, 7, 8, 8a—Tatar hydronaphthalene, etc .; 3- to 4-mer of cyclopentagen, ίί, 4, 9: 5, 8—Dimethano 3a, 4, 4a, 5, 8, 8a, 9, 9a 1 year old Kutahydro 1H benzoindene, 4, 11: 5, 10: 6, 9 Trimethanone 3a, 4, 4a, 5, 5a, 6, 9, 9a, 10, 10a 11, 11a Dodecahydro-1H cyclopentaanthracene and the like. 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 divalent phenol compound. Specific examples of carbonate precursors include phosgene, bischloroformate of divalent phenols, diphenyl carbonate, di-p-trinole carbonate, pheninole p-trinole carbonate, di-p-chlorophenyl carbonate, dinaphthyl. And carbonate. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of aromatic divalent phenolic compounds include 2, 2 bis (4-hydroxyphenol) propane, 2,2 bis (4-hydroxy3,5-dimethylphenol) propane, bis (4-hydroxyphenol). ) Methane, 1,1-bis (4-hydroxyphenenole) ethane, 2,2bis (4-hydroxyphenenole) butane, 2,2bis (4-hydroxy3,5 dimethylphenole) butane, 2,2bis (4-hydroxy 3,5-dipropylphenol) propane, 1,1 bis (4-hydroxyphenyl) cyclohexane, 1,1 bis (4-hydroxyphenyl) 3, 3,5-trimethylcyclohexane, etc. Cited The These may be used alone or in combination of two or more. Preferably, 2,2-bis (4-hydroxyphenyl) propane, 1,1 bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -1,3,3 5-Trimethylcyclohexane is used. In particular, it is preferable to use 2,2bis (4-hydroxyphenyl) propane and 1,1bis (4-hydroxyphenyl) 3,3,5-trimethylcyclohexane together.

[0032] A— 2— 2 · First optical compensation layer (2)

In another embodiment, the first optical compensation layer 12 has a refractive index ellipsoid of nx> ny> nz. The in-plane retardation Re of the first optical compensation layer is 80 to 300 nm, preferably 80 to 200 nm, more preferably 80 to; 160 nm, and particularly preferably 100 to 140 nm. The first optical compensation layer can compensate the optical axis of the polarizer. As described above, by arranging the first optical compensation layer so that the slow axis thereof is orthogonal to the absorption axis of the polarizer, the screen contrast when viewed from an oblique direction can be improved. Thus, one of the features of the present invention is that the slow axis of the first optical compensation layer is orthogonal to the absorption axis of the polarizer. The Nz coefficient (Rth / Re) is preferably 1 <Νζ <2, more preferably 1 <Νζ <1.5.

[0033] The first 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 high molecular film is preferably a norbornene resin or a polycarbonate resin. Details of these resins are as described above in Section A-2-1. 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. As a specific example of the fixed-end biaxial stretching, there is a method in which a polymer film is stretched in the short direction (lateral direction) while running in the longitudinal direction. This method can be apparently lateral uniaxial stretching. The stretching temperature is preferably 135 to 165 ° C, more preferably 140 to 160 ° C. The draw ratio is preferably 1.2 to 3.2 times, more preferably 1.3 to 3.1 times. In this case, the thickness is typically 20 to 80 111, preferably 25 to 75 111, and more preferably 30 to 60 111. [0034] Another specific example of the material for forming the first optical compensation layer exhibiting the refractive index ellipsoid of nx>ny> nz is a non-liquid crystalline material. A non-liquid crystalline polymer is preferable. Specific materials such as polyamides, polyimides, polyesteroles, polyetherolketones, polyamideimides, polyesterimides, etc. These polymers can be used alone or in combination. Alternatively, it may be used as a mixture of two or more, and among these, polyimide is particularly preferred because of its high transparency, high orientation, and high stretchability.

[0035] The first 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 first 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. Specific examples of the polyimide and the method for forming the first optical compensation layer include a polymer and an optical compensation film manufacturing method described in JP-A-2004-46065. In this case, the thickness is typically 0 • ;! to 10 〃m, more preferably 0.1 to 8 〃111, and particularly preferably 0.1 to 5 〃m.

[0036] A— 3. Second optical compensation layer

The second optical compensation layer 13 has a refractive index ellipsoid of nz> nx = ny. The retardation Rth in the thickness direction of the second optical compensation layer is preferably from 50 to 300 nm, more preferably

2

-70 to -250 belly, particularly preferably -90 to -200 belly, most preferably -100 to -18 Onm. 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, it is less than Re force S I Onm.

2

[0037] The second optical compensation layer may be formed of any appropriate material. Preferably, the film is made of a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeopic pick-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 is preferably 0.5, more preferably (0.5 to 8 mm 111, particularly preferably (0.5 to 5 mm).

[0038] A— 4. Third optical compensation layer The third optical compensation layer 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 / Re) exceeds 0.9 and is less than 1 · 1.

3 3

The in-plane retardation Re of the third optical compensation layer is 80 to 200 nm, preferably 100 to 200.

Three

nm, particularly preferably 110 to 150 nm. That is, it can function as a λ / 4 plate. The third optical compensation layer can convert, for example, linearly polarized light having a specific wavelength into circularly polarized light or circularly polarized light into linearly polarized light as a λ / 4 plate.

[0039] The third optical compensation layer may be formed of any appropriate material. Specific examples thereof include the liquid crystal materials described in the above item 2-1-1. When formed of the liquid crystal material, the thickness is typically 0.5 to 10 mm, preferably 0.5 to 8 mm, and more preferably 0.5 to 5111. Another specific example is a stretched polymer film described in the above section A-2-1. In the case of the stretched film, the thickness is typically 5 to 70 111, preferably 10 to 65 mm 111, more preferably 15 to 60 mm 111.

[0040] A— 5. Fourth optical compensation layer

As described above, the laminated optical film of the present invention may further include a fourth optical compensation layer. By providing the fourth optical compensation layer, the screen contrast can be further improved and the color shift can be further reduced. The fourth optical compensation layer 15 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, the Re force is less than Onm. Above

Four

Thickness direction retardation Rth of optical compensation layer 4 depends on the configuration of the applied liquid crystal panel

Four

And can be set to any suitable value. The details will be described in Section B-4 below. When the fourth optical compensation layer is disposed only on one side of the liquid crystal cell, the thickness direction retardation Rth is preferably 50 to 600 nm, more preferably 100-540nm, especially preferred

Four

It is 150 to 500 nm. On the other hand, when the fourth optical compensation layer is disposed on both sides of the liquid crystal cell, the thickness direction retardation Rth is preferably 25 to 300 nm, more preferably 50 to

Four

270 stomachs, particularly preferably 75 to 250 stomachs.

[0041] The fourth optical compensation layer may be formed of any appropriate material as long as the above characteristics are obtained. As a specific example of the fourth optical compensation layer, cholesteric alignment solidification 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 like a cholesteric liquid crystal phase. For example, a “cholesteric alignment solidified layer” can be twisted with a chiral agent in a state where the liquid crystal material exhibits a liquid crystal phase to be aligned in a cholesteric structure (helical structure), and then subjected to polymerization treatment or crosslinking treatment in that state. Thus, it can be formed by fixing the alignment (cholesteric structure) of the liquid crystal material.

[0042] Specific examples of the cholesteric alignment fixed layer include a cholesteric layer described in JP-A-2003-287623.

[0043] The thickness of the fourth optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the fourth optical compensation layer is a cholesteric alignment solidified layer, it is preferably 0.5 to 10 mm, more preferably 0.5 to 8 mm 111, particularly preferably 0.5 to 5 μm. hole.

[0044] Another specific example of the material forming the fourth optical compensation layer is a non-liquid crystalline material. Particularly preferred are non-liquid crystalline polymers. Such a non-liquid crystalline material, unlike a liquid crystalline material, can form a film exhibiting an optical uniaxial property of nx = ny> nz due to its own property that is not related to the orientation of the substrate. As the non-liquid crystal 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 high rigidity. Any one of these polymers may be used alone, or for example, as a mixture of two or more kinds having different functional groups, such as a mixture of polyaryletherketone and polyamide. Good. Among these polymers, polyimide is particularly preferred because of its high transparency, high orientation, and high ductility!

[0045] Specific examples of the polyimide and the method for forming the fourth optical compensation layer include a polymer and a method for producing an optical compensation film described in JP-A-2004-46065.

[0046] The thickness of the fourth optical compensation layer may be any suitable thickness as long as the desired optical characteristics are obtained. It can be set to a negative value. When the fourth optical compensation layer is formed of a non-liquid crystalline material, it is preferably 0.5 to 10 μm, more preferably 0.5 to 8 111, and particularly preferably 0.5 to 5 μm. It is.

[0047] Still another specific example of the material forming the fourth optical compensation layer includes a high molecular weight film formed of a cellulose resin such as triacetyl cellulose (TAC), a norbornene resin, or the like. As the fourth optical compensation layer, a commercially available film can be used as it is. Furthermore, a commercially available film subjected to secondary processing such as stretching and / or shrinking can be used. Commercially available films include, for example, Fuji Photo Film Co., Ltd. Fujitac series (trade name; ZRF80S, TD80UF, TDY—80UU, Konica Minoltaput Co., Ltd., trade name “KC8UX2M”, Nippon Zeon Co., Ltd., trade name “Zeonor”, trade name “Arton” manufactured by JSR Co., Ltd. The norbornene-based monomer constituting the norbornene-based resin is as described above in Section A-2-1, and can satisfy the above optical characteristics. Examples of the stretching method for this purpose include biaxial stretching (longitudinal and transverse equal magnification stretching).

[0048] The thickness of the fourth optical compensation layer can be set to any appropriate value as long as the desired optical characteristics are obtained. When the fourth optical compensation layer is a polymer film formed of a cellulose-based resin, a norbornene-based resin, or the like, preferably 45 to; 105 111, more preferably 50 to 95 am, particularly preferably 55 to 90 μm. m.

[0049] Still another specific example of the fourth optical compensation layer includes a laminate having the cholesteric alignment fixed layer and a plastic film layer. Examples of the resin that forms the plastic film layer include cellulose resins and norbornene resins. These resins are as described above in this section.

[0050] Any appropriate method may 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 fixed layer to the plastic layer, a method of pasting a cholesteric alignment fixed layer and a plastic film layer formed on the base material in advance through an adhesive layer, etc. It is done. The thickness of the adhesive layer is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm.

[0051] A— 6. Polarizer Any appropriate polarizer may be adopted as the polarizer 11 depending on the purpose. For example, a hydrophilic polymer film such as a polybulal alcohol film, a partially formalized polybulal alcohol film, or an ethylene / acetic acid copolymer copolymer partially saponified film is used for two colors such as iodine or a dichroic dye. Polyethylene-based oriented films such as those uniaxially stretched by adsorbing active substances, polyvinyl alcohol dehydrated products and polychlorinated butyl dehydrochlorinated products. Of these, a uniaxially stretched polarizer obtained by adsorbing a dichroic substance such as iodine on a polybulualcohol-based film is particularly preferred because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about !!-80 m.

[0052] A polarizer uniaxially stretched by adsorbing iodine to a polybulualcohol-based film is, for example, dyed by immersing polybulualcohol in an aqueous solution of iodine and stretched 3 to 7 times the original length. It is possible to produce with S. If necessary, it may contain boric acid, zinc sulfate, zinc chloride or the like, or may be immersed in an aqueous solution of potassium iodide or the like. Furthermore, if necessary, the polybulal alcohol film may be immersed in water and washed before dyeing.

[0053] By washing the polybulualcohol-based film with water, it is possible not only to clean the surface of the polybulualcoholic film and the anti-blocking agent. There is also an effect to prevent. The stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be performed after being stretched and then dyed with iodine. Stretching in an aqueous solution of boric acid or potassium iodide or in a water bath.

[0054] 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 that is the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polybutyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyetherolsulfone resins, and polysulfone resins. , Polystyrene-based, polynorbornene-based, polyolefin-based, (meth) acrylic-based, and acetate-based transparent resins. Also, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone Examples thereof include fats and ultraviolet spring curable resins. In addition, for example, a glassy polymer such as a siloxane polymer is also included. In addition, polymer films described in JP-A-2001-343529 (WO 01/37007) can also be used. As a material for this film, for example, a resin containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. The composition can be used, for example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the resin composition.

[0055] The (meth) acrylic resin has a Tg (glass transition temperature) of preferably 115 ° C or higher, more preferably 120 ° C or higher, still more preferably 125 ° C or higher, and particularly preferably 130 ° C. That is all. It is because it can be excellent in durability. The upper limit 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.

[0056] As the (meth) acrylic resin, any appropriate (meth) acrylic resin can be adopted as long as the effects of the present invention are not impaired. 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 alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylic acid norbornyl copolymer). Preferably, poly (meth) acrylic acid C alkyl such as methyl poly (meth) acrylate is used. More preferably, methyl methacrylate is the main component (50-

1 -6

100% by weight, preferably 70 to 100% by weight).

[0057] Specific examples of the (meth) acrylic resin include, for example, a ring structure in the molecule described in Ataripet VH and Ataripet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. (Meth) acrylic resins having high T g (meth) acrylic resins obtained by intramolecular crosslinking or intramolecular cyclization reactions.

[0058] The (meth) acrylic resin has high! /, Heat resistance, high! /, Transparency, high! /, And mechanical strength. In view of this, (meth) acrylic resins having a rataton ring structure are particularly preferred!

[0059] Examples of the (meth) acrylic resin having a laton ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, and JP 2002-.

Examples thereof include (meth) acrylic resins having a rataton ring structure as described in JP-A-254544 and JP-A-2005-146084.

[0060] The (meth) acrylic resin having the latatotone ring structure preferably has a mass average molecular weight (sometimes referred to as a weight average molecular weight) force, preferably 1000-2000000, more preferably 5000-1

000000, more preferable <10000 or 500,000, more preferable <50000 to 500,000.

[0061] The (meth) acrylic resin having a latatotone 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 130 ° C or higher. Preferably it is 135 ° C, most preferably 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 above-mentioned rataton ring structure is not particularly limited! /, But is preferably 170 ° C. or less from the viewpoint of moldability and the like.

[0062] In this specification, "(meth) acrylic" refers to acrylic and / or methacrylate.

[0063] 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.

[0064] As the thicknesses of the first protective layer and the second protective layer, any appropriate thickness can be adopted 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 1-500, πι, particularly preferably (5 to 150 μm).

[0065] On the opposite side of the second protective layer from the polarizer, a hard coat treatment, an antireflection treatment, a sticking prevention treatment, an antiglare treatment, or the like may be performed as necessary.

[0066] The thickness direction retardation (Rth) of the first protective layer provided between the polarizer and the optical compensation layer is preferably smaller than the preferable value. Cellulose films generally used as protective films are, for example, triacetyl cellulose film. In the case of a film having a thickness of 80 m, the thickness direction retardation (Rth) is about 60 nm. Therefore, the cellulose-based film having a large thickness direction retardation (Rth) is subjected to an appropriate treatment for reducing the thickness direction retardation (Rth), thereby suitably obtaining the first protective layer. Touch with S.

[0067] Any appropriate processing method can be adopted as the above-described processing for reducing the thickness direction retardation (Rth). For example, a base material such as polyethylene terephthalate, polypropylene, or stainless steel coated with a solvent such as cyclopentanone or methyl ethyl ketone is bonded to a general cellulose film and dried by heating (for example, about 80 to 150 ° C). 3 to about 10 minutes), and then the base film is peeled off; a solution obtained by dissolving norbornene resin, acrylic resin, etc. in a solvent such as cyclopentanone, methyl ethyl ketone, etc. For example, a method may be used in which a coated film is peeled off after being applied to a glass-based film and dried by heating (for example, 80 to approximately 150 ° C for 3 to 10 minutes).

[0068] The material constituting the cellulose film is preferably a fatty acid-substituted cellulose polymer such as diacetyl cellulose and 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.; By controlling to 1, the thickness direction retardation (Rth) can be controlled to be small.

[0069] By adding a plasticizer such as dibutyl phthalate, p-toluenesulfonic anilide, acetotiltyl taenoate 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, still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the fatty acid-substituted cellulose polymer.

[0070] The processes for reducing the thickness direction retardation (Rth) may be combined as appropriate. 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, and particularly preferably −61 111 to +61 111, most preferably from 3 nm to +3 nm. The in-plane retardation Re (550) of the first protective layer is preferably Onm or more and 10 nm or less, more preferably Onm or more and 6 nm or less, and particularly preferably Onm or more and 3 nm or less. [0071] 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.

[0072] 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. A typical example of the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer. The thickness of the acrylic pressure-sensitive adhesive layer is preferably;! -30 μm, more preferably 3-25 μm.

[0073] As described above, when the first optical compensation layer 12 can function as a protective layer for the polarizer 11, the polarizer and the first optical compensation layer are laminated via any appropriate adhesive layer. Is done. As described above, when the first optical compensation layer showing the refractive index ellipsoid of nx> ny> nz is produced by fixed-end biaxial stretching, the slow axis can occur in the short direction. On the other hand, the absorption axis direction of the polarizer can occur in the stretching direction (longitudinal direction). Therefore, when the slow axis of the first optical compensation layer is arranged so as to be orthogonal to the absorption axis of the polarizer as in the present invention, the first optical compensation layer and the polarizer are roll-to-roll. It can be laminated continuously with rolls. Examples of the adhesive used for laminating the polarizer and the first optical compensation layer include an adhesive containing polybulal alcohol resin, a crosslinking agent, and a metal compound colloid.

[0074] Examples of the polybulal alcohol-based resin include polybulal alcohol resin and acetoacetyl group-containing polybulal alcohol resin. Preferably, it is a polybutyl alcohol resin containing a acetoacetyl group. This is because durability can be improved.

[0075] Examples of the polybula alcohol-based resin include a saponified product of polyacetate butyl, a derivative of the saponified product; a saponified product of a copolymer with a monomer copolymerizable with butyl acetate; Examples thereof include modified polybulal alcohols in which bull alcohol is acetalized, urethanized, etherified, grafted, or phosphorylated. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene; (Meth) aryl sulfonic acid (soda), sulfonic acid soda (monoalkyl malate), disulfonic acid soda alkyl malate, Ν-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, Ν-bullpyrrolidone, Ν-bull pyrrolidone derivative Can be mentioned. this These resins can be used alone or in combination of two or more.

[0076] The average degree of polymerization of the polybulal alcohol resin is preferably 10 from the viewpoint of adhesiveness.

It is about 0 to 5000, more preferably 1000 to 4000. The average saponification degree, from the viewpoint of adhesiveness, preferably 85; 100 mole ^_0/0; 100 moles ^_0/0 degree, more preferably 90.

[0077] The above-mentioned acetoacetyl group-containing polybutyl alcohol resin is obtained, for example, by reacting a polybutyl alcohol resin with diketene by an arbitrary method. As a specific example, a method in which diketene is added to a dispersion in which a polybulualcohol-based resin is dispersed in a solvent such as acetic acid; A method of adding a diketene; a method of directly contacting a diketene gas or a liquid diketene with a polybutyl alcohol resin.

[0078] The degree of modification of the acetoacetyl group of the above-mentioned acetoacetyl group-containing polybutyl alcohol-based resin is typically 0.1 mol% or more, preferably about 0 · ;! to about 40 mol%, more preferably; -20%, particularly preferably 2-7 mol%. If the amount is less than 1 mol%, water resistance may be insufficient. If it exceeds 40 mol%, the effect of improving water resistance is small. The degree of modification of the acetoacetyl group is a value measured by NMR.

[0079] Any appropriate crosslinking agent may be employed as the crosslinking agent. A compound having at least two functional groups having reactivity with the polyvinyl alcohol resin is preferable. For example, ethylenediamine, triethylenediamine, hexamethylenediamine and other alkylenediamines having two alkylene groups and two amino groups; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylol Propanetolylene diisocyanate adduct, triphenylmethane triisocyanate, methylenebis (4 phenylmethane triisocyanate, isophorone diisocyanate and their isocyanates such as ketoxime block or phenol block; ethylene Glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, aldehyde , Monoaldehydes such as propionaldehyde, butyraldehyde; glyoxer nore, malondialdehyde, succindialdehyde, glutardialdehyde, maleinanol Dialdehydes such as dehydride and phthaldialdehyde; aminoformaldehyde resins such as methylolurea, methylolmelamine, alkylated methylolurea, alkylated methylolated melamine, acetoguanamine, and condensates of benzoguanamine and formaldehyde; sodium, potassium, Examples thereof include divalent metals such as magnesium, calcium, aluminum, iron and nickel, and salts of trivalent metals and oxides thereof. Of these, aminoformaldehyde resins are preferred for dialdehydes. As the amino-formaldehyde resin, a compound having a methylol group is preferred. Of these, methylol melamine, which is preferred as a compound having a methylol group, is particularly preferred.

[0080] The blending amount of the cross-linking agent may be appropriately set according to the type of the polybulualcohol-based resin. Typically, it is about 10 to 60 parts by weight, preferably 20 to 50 parts by weight, with respect to 100 parts by weight of the polybutyl alcohol resin. This is because the adhesiveness can be excellent. In addition, when there are many compounding quantities of a crosslinking agent, reaction of a crosslinking agent advances in a short time, and there exists a tendency for an adhesive agent to gelatinize. As a result, the usable time (pot life) as an adhesive becomes extremely short, and industrial use may be difficult. Since the adhesive of this embodiment contains a metal compound colloid described later, it can be used with good stability S even when the amount of the crosslinking agent is large.

[0081] The metal compound colloid may be one in which metal compound fine particles are dispersed in a dispersion medium, and is electrostatically stabilized due to mutual repulsion of the same kind of charge of the fine particles, and has permanent stability. Can be a thing. The average particle size of the fine particles forming the metal compound colloid can be any appropriate value as long as it does not adversely affect the optical properties such as polarization properties. It is preferably;! To 100 nm, more preferably;! To 50 nm. This is because the fine particles can be uniformly dispersed in the adhesive layer, ensuring adhesion and suppressing nicks. “Knick” refers to a local uneven defect generated at the interface between the polarizer and the protective layer.

[0082] Any appropriate compound can be adopted as the metal compound. For example, metal oxides such as alumina, silica, zirconium, titania, etc .; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate, calcium phosphate; minerals such as celite, talc, clay, kaolin It is done. Alumina is preferred. [0083] The metal compound colloid is typically present in the form of a colloidal solution dispersed in a dispersion medium. Examples of the dispersion medium include water and alcohols. The solid content concentration in the colloidal solution is typically about !! to 50% by weight. The colloidal solution may contain acids such as nitric acid, hydrochloric acid, acetic acid as a stabilizer.

[0084] The compounding amount of the metal compound colloid (solid content) is preferably 200 parts by weight or less, more preferably 10 to 200 parts by weight, and still more preferably 100 parts by weight of polybulal alcohol resin. 20 to 175 parts by weight, most preferably 30 to 150 parts by weight. This is because the occurrence of nicks can be suppressed while ensuring adhesiveness.

[0085] The adhesive of this embodiment includes a coupling agent such as a silane coupling agent and a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, and a hydrolysis stabilizer. Stabilizers and the like can be included.

[0086] The form of the adhesive of the present embodiment is preferably an aqueous solution (resin solution). The resin concentration is preferably 0.5;! To 15% by weight, more preferably 0.5 to 10% by weight, from the viewpoint of coating property and storage stability. The viscosity of the resin solution is preferably 1 to 50 mPa's. The pH of the resin solution is preferably 2 to 6, more preferably 2.5 to 5, more preferably 3 to 5, and most preferably 3.5 to 4.5. Usually, the surface charge of a metal compound colloid can be controlled by adjusting the pH. The surface charge is preferably a positive charge. By having a positive charge, for example, generation of nicks can be suppressed.

[0087] Any appropriate method can be adopted as a method for preparing the resin solution. For example, a method of blending a metal compound colloid with a polyvinyl alcohol resin and a crosslinking agent mixed in advance and adjusted to an appropriate concentration can be mentioned. In addition, after mixing the polybulualcohol-based resin and the metal compound colloid, the cross-linking agent can be mixed in consideration of the time of use. The concentration of the resin solution may be adjusted after preparing the resin solution.

[0088] B. Liquid crystal panel

B- 1. Overall configuration of LCD panel

FIG. 2 (a) 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; a 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 the other side of the liquid crystal cell 20 (illustrated example) Then, a laminated film 30 arranged on the viewing side) is provided. The laminated film 30 includes the polarizer 11 and the fifth optical compensation layer 16. In the present embodiment, the refractive index ellipsoid of the fifth optical compensation layer 16 shows a relationship of nx> ny = nz, and has an in-plane retardation Re force S80 to 200 nm.

Five

. The laminated film 30 is provided with a first protective layer between the polarizer 11 and the fifth optical compensation layer 16 as necessary, and on the opposite side of the polarizer 11 from the fifth optical compensation layer 16. Two protective layers are provided. Although not shown, the laminated film 30 may further include any appropriate other optical compensation layer. 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. 2B 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 the 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 the other side of the liquid crystal cell 20 ( And a laminated film 30 ′ disposed on the viewing side in the illustrated example. The laminated film 30 ′ includes the polarizer 11, the fifth optical compensation layer 16, and the fourth optical compensation layer 15. In the laminated film 30 ′, a first protective layer is provided between the polarizer 11 and the fifth optical compensation layer 16 as necessary, and the opposite side of the polarizer 11 from the first optical compensation layer 12 is provided. A second protective layer is provided on the substrate. Further, although not shown, the laminated film 30 ′ may further include any appropriate other optical compensation 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.

[0090] Unlike the illustrated example, the laminated optical film 10 may be disposed instead of the laminated optical film 10 '. Further, unlike the illustrated example, the laminated optical film 10 ′ (10) may be arranged on the viewing side, and the laminated films 30 and 30 ′ may be arranged on the backlight side. Preferably, as shown in the drawing, the laminated optical film 10 ′ (10) is disposed on the backlight side.

[0091] The slow axis of the fifth optical compensation layer 16 constituting the laminated film 30, 30 'may be any appropriate relative to the absorption axis of the polarizer 11 constituting the laminated film 30, 30'. They are stacked so as to define the angle. The angle is preferably 30 to 60 °, more preferably 35 to 55 °, particularly preferably 40 to 50 °, and most preferably 43 to 47 °.

The absorption axes of the polarizers 11 and 11 arranged on both sides of the liquid crystal cell 20 of the liquid crystal panels 100 and 100 ′ are preferably arranged so as to be substantially orthogonal. [0093] 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). The other substrate (active matrix substrate) 21 ′ includes a switching element (typically TFT) (not shown) for controlling the electro-optical characteristics of the liquid crystal, and a scanning line (Fig. A signal line (not shown) for supplying a source signal and a pixel electrode (not shown) are provided. The color filter 1 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.

As the drive mode of the liquid crystal cell 20, any appropriate drive mode can be adopted. The VA mode is preferable. FIG. 3 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in Fig. 3 (a), when no voltage is applied, the liquid crystal molecules are aligned perpendicular to 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 one polarizer 11 and entered the liquid crystal layer 22 has a long axis of vertically aligned liquid crystal molecules. Proceed along the direction. 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 other polarizer 11 having a polarization axis perpendicular to one polarizer 11. As a result, a display of a heel state is obtained when no voltage is applied (normally black mode). As shown in Fig. 3 (b), 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 are birefringent 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 according to the inclination of the liquid crystal molecules. . Light that passes through the liquid crystal layer when a predetermined maximum voltage is applied is, for example, linearly polarized light whose polarization orientation is rotated by 90 °, and therefore is transmitted through the other polarizer 11 to display a bright state. Is obtained. When no voltage is applied again, the display of the heel state can be restored by the orientation regulating force. Also change the applied voltage By controlling the tilt of the liquid crystal molecules and changing the transmitted light intensity from the other polarizer 11, gradation display is possible.

[0095] B-3. Fifth optical compensation layer

In the fifth optical compensation layer 16, preferably, the refractive index ellipsoid shows a relationship of nx> ny = nz, and the in-plane retardation Re is 80 to 200 nm. That is, it can function as a λ / 4 plate.

Five

As the fifth optical compensation layer, the same layer as the third optical compensation layer can be adopted.

[0096] IV-4. Thickness direction retardation of fourth optical compensation layer

As shown in FIG. 2 (a), when the fourth optical compensation layer 15 is disposed only on one side of the liquid crystal cell 20, the thickness direction retardation Rth of the fourth optical compensation layer is preferably Is 50

Four

It is ˜600 nm, more preferably ί 100 to 540 nm, and particularly preferably ί 150 to 500 nm. On the other hand, as shown in FIG. 2 (b), when the fourth optical compensation layer 15 is disposed on both sides of the liquid crystal cell 20, the thickness direction retardation Rth of each of the fourth optical compensation layers is preferably Is

Four

, Approximately half of the thickness direction retardation when 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.

[0097] B— 5. 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.

Example

[0098] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples! /. The measuring method of each characteristic is as follows.

[0099] (1) Measurement of phase difference value

Automatic measurement using KOBRA-WPR made 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. Simi Yurayon is a liquid crystal display simulator “LCD MASTER” made by Shintech. 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 Contrastl 60D” manufactured by ELDIM.

[0100] [Example 1]

(Preparation of polarizing plate)

After dyeing the polybulualcohol film in an aqueous solution containing iodine, a polarizer was obtained by uniaxially stretching 6 times between rolls having different speed ratios in an aqueous solution containing boric acid. A triacetylcellulose film (thickness 40 m, manufactured by Konica Minolta, trade name: KC4UYW) is used as a protective layer (first protective layer and second protective layer) on both sides of this polarizer. Affixed via an adhesive (thickness: 0.11 11 m), the in-plane phase difference Re (550) of the protective layer is 0.9 nm, and the thickness direction retardation Rth (550) is 1.2 nm. In this way, a polarizing plate was produced, where Re (550) is a value measured with light having a wavelength of 550 nm at 23 ° C.

[0101] (Preparation of the first optical compensation layer)

Long norbornene resin film (manufactured by Zeon Corporation, trade name Zeonor, thickness 40 m, photoelastic coefficient ^{^{3. 10 X 10- 12 m 2 /}} N) subjected to uniaxial stretching to 52 times 1. 140 ° C Thus, a long film was produced. This film had a thickness of 35 m, an in-plane retardation Re of 140 nm, and a thickness direction retardation Rth 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.

[0102] (Production of second optical compensation layer)

Side-chain liquid crystal polymer represented by the following chemical formula (1) (numerals 65 and 35 in the formula indicate mol% of the monomer unit and are represented by a block polymer for convenience! /, Weight average molecular weight 5000) 20 80 parts by weight of a polymerizable liquid crystal (BASF: trade name Palio color LC242) and a photopolymerization initiator (Ciba Specialty Chemicals: trade name Irgacure 907) 5 parts by weight of cyclopentanone A liquid crystal coating solution was prepared by dissolving in 200 parts by weight. Then, after applying the coating solution on a base film (norbornene-based resin film: trade name Zeonor, manufactured by Nippon Zeon Co., Ltd.) with a bar coater, it is at 80 ° C for 4 minutes. The liquid crystal was aligned by heating and drying. By irradiating the liquid crystal layer with ultraviolet rays and curing the liquid crystal layer, a liquid crystal solidified layer serving as a second optical compensation layer was formed on the substrate. The in-plane retardation of this layer is substantially zero, and the thickness direction retardation Rth is 120 nm.

2

I got it.

[Chemical 1]

[0104] (Production of third optical compensation layer)

The same film as the first optical compensation layer was used.

[0105] (Fabrication of fourth optical compensation layer)

90 parts by weight of a nematic liquid crystalline compound represented by the following chemical formula (2), 10 parts by weight of a chiral agent represented by the following chemical formula (3), 5 parts by weight of a photopolymerization initiator (Irgacure 907: manufactured by Ciba Specialty One Chemicals) Then, 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 by irradiating with ultraviolet rays, and a fourth optical material is formed on the substrate. A cholesteric alignment solidified layer serving as a compensation layer was formed. The cholesteric alignment solidified layer has a thickness of 3 m and a thickness direction retardation Rth of 120 nm.

Four

The in-plane retardation Re was substantially zero.

Four

[0106] [Chemical 2]

[0107] (Fifth optical compensation layer fabrication)

The same film as the first optical compensation layer was used.

[0108] (Preparation of laminated film A)

A cholesteric alignment solidified layer as a fourth optical compensation layer was adhered to the fifth optical compensation layer with an isocyanate adhesive (thickness: 511 m), and the substrate (biaxially stretched PET film) was removed. A laminate in which the cholesteric alignment solidified layer was transferred to the fifth optical compensation layer was obtained. On the fifth optical compensation layer side of this laminate, the polarizing plate obtained above was laminated via an acrylic pressure-sensitive adhesive (thickness 12 ^ 111). Here, the fifth optical compensation layer was laminated so that the slow axis was 45 ° clockwise with respect to the absorption axis of the polarizer of the polarizing plate. In this way, a laminated optical film A was obtained.

[0109] (Preparation of laminated optical film B)

A liquid crystal solidified layer serving as a second optical compensation layer is adhered to the first optical compensation layer with an isocyanate adhesive (thickness 5 am), and the base material (norbornene resin film) is removed. A laminate 1 was obtained in which the second optical compensation layer was transferred to the optical compensation layer.

A cholesteric alignment solidified layer as a fourth optical compensation layer is adhered to the third optical compensation layer with an isocyanate adhesive (thickness: 511 m), and the substrate (biaxially stretched PET film) is removed. Thus, a laminate 2 in which the cholesteric alignment solidified layer was transferred to the third optical compensation layer was obtained. On the third optical compensation layer side of the laminate 2, the laminate 1 and the polarizing plate were laminated in this order via an acrylic pressure-sensitive adhesive (thickness: 12πι). At this time, the laminated body 1 was laminated so that the first optical compensation layer was on the polarizing plate side. The laminar axial forces of the first optical compensation layer and the third optical compensation layer were laminated so as to be 90 ° and 45 ° clockwise with respect to the absorption axis of the polarizer of the polarizing plate, respectively. In this way, a laminated optical film Β was produced.

[0110] (Production of liquid crystal panel)

The liquid crystal cell was removed from the Sony PlayStation Portable (with VA mode liquid crystal cell), and the laminated film Α was attached to the viewing side of the liquid crystal cell with an acrylic adhesive (thickness 20 πι). At this time, the fourth optical compensation layer was attached so as to be on the liquid crystal cell side. Further, the laminated optical film Β was attached to the backlight side of the liquid crystal cell via an acrylic adhesive (thickness 20 ΐη). The fourth optical compensation layer is liquid crystal Affixed to the cell side. The laminated film A was laminated such that the polarizer absorption axis and the laminated optical film B polarizer absorption axis were substantially perpendicular to each other. Thus, a liquid crystal panel was produced.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The results are shown in Fig. 4. Also, the viewing angle dependence of contrast of a liquid crystal display device manufactured using the obtained liquid crystal panel was measured. The results are shown in Fig. 5.

[0111] [Example 2]

(Preparation of laminated optical film C)

The laminated optical film was the same as the laminated optical film B except that the film shown below was used as the first optical compensation layer and that the Rth of the second optical compensation layer was −140 nm.

2

C was produced.

(First optical compensation layer)

Norbornene resin film long (manufactured by Zeon Corporation, trade name Zeonor, thickness 60 m, photoelastic coefficient ^{^{3. l X 10_ 12 m 2 /}} N) of the fixed end biaxially stretched 1.7 times at 0.99 ° C By doing so, a long film was produced. The in-plane retardation Re of this film was 120 nm, the thickness direction retardation Rth was 156 nm, and the Nz coefficient (Rth / Re) was 1.3. The obtained film was punched out to a size corresponding to the liquid crystal cell to obtain a first optical compensation layer.

[0112] (Production of liquid crystal panel)

A liquid crystal panel was obtained in the same manner as in Example 1 except that the laminated optical film C was used instead of the laminated optical film B.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The result is shown in FIG. In addition, the contrast of a liquid crystal display device manufactured using the obtained liquid crystal panel was measured. The results are shown in FIG.

[0113] [Example 3]

(Preparation of aqueous adhesive solution)

Polyacetyl alcohol resin containing acetoacetyl group (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) 100 parts by weight of methylolmelamine 50 parts by weight was dissolved in pure water under a temperature condition of 30 ° C. to obtain an aqueous solution adjusted to a solid content concentration of 3.7%. An aqueous adhesive solution was prepared by adding 18 parts by weight of an aqueous colloidal alumina solution (average particle size 15 nm, solid content concentration 10%, positive charge) to 100 parts by weight of this aqueous solution. The viscosity of the adhesive aqueous solution was 9.6 mPa's. The pH of the aqueous adhesive solution was 4 to 4.5.

[0114] (Production of laminated optical film C ')

After dyeing the polybulualcohol film in an aqueous solution containing iodine, a polarizer was obtained by uniaxially stretching 6 times between rolls having different speed ratios in an aqueous solution containing boric acid. A triacetyl cellulose film (trade name: KC4U YW) as a second protective layer was pasted on one side of this polarizer via a polybutyl alcohol adhesive (thickness 0 · 1 m). Next, the adhesive aqueous solution obtained above was applied to the other surface of the polarizer with a thickness of 0.1 m, and the first optical compensation layer obtained in Example 2 was attached. . At this time, lamination was performed so that the slow axis of the first optical compensation layer was orthogonal to the absorption axis of the polarizer. Thus, a laminate I was obtained.

On the side of the first optical compensation layer of the laminate I, a liquid crystal solidified layer (Rth

2

: 140 nm) is bonded with an isocyanate adhesive (thickness 5 μm), the base material (norbornene resin film) is removed, and the second optical compensation layer is transferred to laminate I II was obtained. The laminate 2 obtained in Example 1 was laminated on the second optical compensation layer side of the laminate II via an acrylic pressure-sensitive adhesive (thickness: 12πι). At this time, lamination was performed such that the third optical compensation layer of the laminate 2 was on the laminate II side. The third optical compensation layer is laminated so that the slow axis is 45 ° clockwise with respect to the absorption axis of the polarizer. In this way, a laminated optical film C ′ was produced.

[0115] (Production of liquid crystal panel)

A liquid crystal panel was obtained in the same manner as in Example 2 except that the laminated optical film C ′ was used instead of the laminated optical film C.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The results are shown in FIG. In addition, the contrast of a liquid crystal display device manufactured using the obtained liquid crystal panel was measured. The results are shown in FIG.

[0116] [Comparative Example 1] A liquid crystal panel was obtained in the same manner as in Example 1 except that the laminated film A was used instead of the laminated optical film B.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The result is shown in FIG. Moreover, the contrast of the liquid crystal display device produced using the obtained liquid crystal panel was measured. The result is shown in Fig. 11.

[0117] [Comparative Example 2]

(Production of laminated film D)

A laminated film D was produced in the same manner as the laminated optical film B except that the slow axis of the first optical compensation layer and the absorption axis of the polarizer of the polarizing plate were laminated in parallel (0 °). .

[0118] (Production of liquid crystal panel)

A liquid crystal panel was obtained in the same manner as in Example 1 except that the laminated film D was used instead of the laminated optical film B.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The results are shown in FIG. Moreover, the contrast of the liquid crystal display device produced using the obtained liquid crystal panel was measured. The results are shown in Figure 13.

[Comparative Example 3]

(Production of laminated film E)

A laminated film E is produced in the same manner as the laminated optical film C, except that the slow axis of the first optical compensation layer and the absorption axis of the polarizer of the polarizing plate are parallel (0 °). .

[0120] (Production of liquid crystal panel)

A liquid crystal panel is obtained in the same manner as in Example 1 except that the laminated film E is used instead of the laminated optical film B.

Computer simulations were conducted on the viewing angle dependence of contrast in liquid crystal display devices using such liquid crystal panels. The results are shown in FIG.

[0121] Table 1 summarizes the overall configuration of the panels of Examples;! -3 and Comparative Examples 1-3. The angle (counterclockwise) when the absorption axis of the polarizer on the knock light side is 0 ° is also shown. [0122] [Table 1]

As is clear from FIGS. 4 to 14, the liquid crystal panels of Examples 1 to 3 of the present invention were superior in contrast to the liquid crystal panels of Comparative Examples! To 3. Comparing Example 1 with Comparative Example 2, Examples 2 and 3 and Comparative Example 3, contrast is remarkably increased by making the slow axis of the first optical compensation layer and the absorption axis of the polarizer perpendicular to each other. It turns out that it is excellent. Further, it was confirmed that the liquid crystal panel of the example of the present invention had a smaller color shift than the liquid crystal panel of the comparative example. Industrial applicability The laminated optical film, liquid crystal panel, and liquid crystal display device of the present invention can be suitably applied to mobile phones, liquid televisions, and the like.

Claims

The scope of the claims

[1] Polarizer,

A first optical compensation layer having a refractive index ellipsoidal force x> ny = nz and an in-plane retardation Re force of 0 to 300 nm;

A second optical compensation layer whose refractive index ellipsoid shows a relationship of nz> nx = ny,

Refractive index ellipsoidal force x> ny = nz, with in-plane retardation Re force 0 to 200 nm

Three

And at least a third optical compensation layer in this order,

A laminated optical finem in which the absorption axis of the polarizer and the slow axis of the first optical compensation layer are orthogonal to each other.

[2] Polarizer,

A first optical compensation layer having a refractive index ellipsoidal force x> ny> nz and an in-plane retardation Re force of 0 to 300 nm;

Three

And at least a third optical compensation layer in this order,

[3] The fourth optical compensation layer is further provided on the opposite side of the third optical compensation layer from the second optical compensation layer, and the refractive index ellipsoid shows a relationship of nx = ny> nz. The laminated optical film according to claim 1 or 2.

[4] A liquid crystal panel comprising a liquid crystal cell and the laminated optical film according to any one of claims 1 to 3.

5. The liquid crystal panel according to claim 4, wherein the laminated optical film is disposed on the backlight side.

[6] The relationship between the polarizer and refractive index ellipsoidal force ¾x> ny = nz, with in-plane phase difference Re force 0 to 20

Five

6. The liquid crystal panel according to claim 5, wherein a laminated film including a fifth optical compensation layer which is Onm is disposed on the viewing side.

7. The liquid crystal panel according to any one of claims 4 to 6, wherein the liquid crystal cell is in a VA mode. [8] A liquid crystal display device comprising the liquid crystal panel according to any one of claims 4 to 7.