JP3880996B2 - Elliptical polarizing plate and liquid crystal display device - Google Patents

Description

The present invention relates to an elliptically polarizing plate in which an optical film in which a retardation film is laminated and a polarizer. The elliptically polarizing plate of the present invention is suitable for a horizontal electric field type (IPS mode) active matrix liquid crystal display device.

  Conventionally, as a liquid crystal display device, a so-called TN mode liquid crystal display device in which liquid crystals having positive dielectric anisotropy are twisted and horizontally aligned between substrates facing each other is mainly used. However, in the TN mode, due to its driving characteristics, even if an attempt is made to perform black display, birefringence is caused by liquid crystal molecules in the vicinity of the substrate, resulting in light leakage, making it difficult to perform complete black display. In contrast, a horizontal electric field type liquid crystal display device performs pixel display by forming an electric field parallel to a liquid crystal substrate between a pixel electrode and a common electrode, and forms a TN mode in which an electric field perpendicular to the substrate is formed. Compared to the method and the like, there is an advantage that complete black display is possible and a wide viewing angle can be obtained.

  However, the conventional horizontal electric field type active matrix liquid crystal display device can display almost completely black in the normal direction of the panel, but when observing the panel from the direction deviated from the normal direction, it is arranged above and below the liquid crystal cell. In the direction deviating from the optical axis direction of the polarizing plate, the light leakage unavoidable due to the characteristics of the polarizing plate occurs, resulting in a problem that the viewing angle is narrowed and the contrast is lowered. Further, when observed from an oblique direction, the optical path of light becomes long, and the apparent retardation of the liquid crystal layer changes. For this reason, when the viewing angle is changed, the wavelength of transmitted light changes, and the color of the screen changes and appears, and a color shift occurs depending on the viewing direction.

Various proposals have been made in order to suppress the reduction in contrast depending on the viewing angle and to improve the color shift in such a horizontal electric field type liquid crystal display device (Patent Documents 1 and 2). For example, Patent Document 1 proposes a technique in which a compensation layer having optical anisotropy is interposed between a liquid crystal layer and a pair of polarizing plates sandwiching the liquid crystal layer. Although this technique is effective in improving color shift, it is not sufficient to suppress a decrease in contrast. Patent Document 2 proposes a technique in which a first and a second retardation plate are interposed between a liquid crystal layer and a pair of polarizing plates sandwiching the liquid crystal layer. Although it is described that this technique is effective for suppressing a decrease in contrast and improving a color shift, a higher improvement effect is desired.
JP 11-133408 A JP 2001-242462 A

The present invention is an elliptically polarizing plate in which a retardation film and a polarizer are laminated, and is applied to a lateral electric field type active matrix liquid crystal display device, which can suppress a decrease in contrast at a wide viewing angle, and can achieve color shift. It aims at providing the thing with a high improvement effect.

Another object of the present invention is to provide a lateral electric field type active matrix liquid crystal display device using the elliptically polarizing plate, which can suppress a decrease in contrast at a wide viewing angle and has a high effect of improving color shift. .

  As a result of intensive studies to solve the above problems, the present inventors have found that the object can be achieved by the elliptically polarizing plate shown below, and have completed the present invention.

That is, the present invention is made of a thermoplastic polymer containing a cyclic polyolefin resin, the direction in which the in-plane refractive index is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis. Retardation film A having positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented when the refractive indexes in the respective axial directions are nx, ny, nz,
The direction in which the in-plane refractive index is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis. The refractive index in each axial direction is nx. ₁ , ny ₁ , nz ₁ , an optical film formed by laminating a retardation film B having positive refractive index anisotropy (nz ₁ > nx ₁ ≈ny ₁ ),
It is an elliptically polarizing plate laminated on one side of the polarizer so that the slow axis of the retardation film A and the absorption axis of the polarizer are orthogonal to each other,
The elliptical polarizing plate is laminated with an optical film so as to be in the order of a retardation film A and a retardation film B from a polarizer .
The polarizer and the retardation film A are laminated with an adhesive,
The elliptically polarizing plate relates to an elliptically polarizing plate that is used in a liquid crystal display device having a lateral electric field mode (IPS mode) so that the optical film side is the liquid crystal cell side.

  A retardation film A and a retardation film B are laminated on the elliptically polarizing plate of the present invention. The retardation film A has a compensation function by uniaxially oriented positive refractive index anisotropy, and the retardation film B can also control the retardation in the thickness direction. Accordingly, it is possible to suppress a decrease in contrast based on a change in the axis of the polarizer caused by a change in viewing angle, improve a color shift, and compensate for a wide viewing angle.

  The retardation film A contains a cyclic polyolefin resin. Cyclic polyolefin resin has a small photoelastic coefficient, and can suppress unevenness that is likely to occur in tensile stress, durability tests, and the like, particularly in large panel applications such as the transverse electric field method (IPS mode).

  In the elliptically polarizing plate of the present invention, the retardation film A is laminated so that the slow axis thereof is perpendicular to the absorption axis of the polarizer. Arranging perpendicularly as described above is preferable in terms of obtaining high contrast.

  In addition, the optical film in which the retardation film A and the retardation film B are laminated is laminated on the polarizer, and the optical film also serves as a protective film. It is excellent in that the color shift can be improved.

The elliptically polarizing plate, a polarizer, a retardation film A, and the optical film so that the order of the retardation film B are laminated, it is possible to suppress a reduction in contrast in a wide viewing angle, and the effect of improving the color shift This is preferable.

  In the elliptically polarizing plate, the retardation film A is preferably a film containing a norbornene resin. A film containing a norbornene resin is preferable from the viewpoint of excellent durability under high temperature and high temperature and high humidity conditions.

In the elliptically polarizing plate, the retardation film B has a thickness direction retardation: {((nx ₁ + ny ₁ ) / 2) −nz ₁ } in order to suppress a decrease in contrast and color shift at a wide viewing angle. Xd (thickness: nm) is preferably −500 nm to −10 nm. The retardation in the thickness direction of the retardation film B is more preferably −300 nm to −30 nm. Furthermore, -200 to -50 nm is preferable.

  In the elliptically polarizing plate, the retardation film B having the above refractive index can be used without particular limitation, but a film containing a side chain type liquid crystal polymer is suitable. In addition, as a material of the retardation film B, a material having a small in-plane refractive index in the stretching direction, that is, a so-called negative optical material can be exemplified. Examples of such materials include styrene resins and acrylic resins.

  In the elliptically polarizing plate, a λ / 4 plate can be used as the retardation film A.

Further the invention features in that the elliptically polarizing plate are laminated, an active matrix type liquid crystal display device of the drive mode horizontal electric field method (IPS mode), relates. An image display device such as a liquid crystal display device to which the elliptically polarizing plate is applied can realize a wide viewing angle, can suppress a decrease in contrast even when the display screen is viewed from an oblique direction, and can improve a color shift.

The liquid crystal display device can be formed by arranging the elliptically polarizing plate of the present invention on one side or both sides of the liquid crystal cell instead of the conventional polarizing plate. The arrangement of the elliptically polarizing plate of the present invention with respect to the liquid crystal cell is such that the optical film in which the retardation film A and the retardation film B are laminated is positioned on the liquid crystal cell side (that is, the optical film is between the polarizer and the liquid crystal cell). In view of display quality, it is preferable that the optical film is arranged between polarizers arranged in crossed Nicols in the display device.

The elliptically polarizing plate of the present invention will be described below with reference to FIG . As shown in FIG. 1, in the elliptically polarizing plate of the present invention, an optical film 2 in which a retardation film A and a retardation film B are laminated is laminated on one side of a polarizer 1a. Moreover, as shown in FIG. 1 , the protective film 1b can be laminated | stacked on the other one side of the polarizer 1a. This is shown as a polarizing plate 1. The optical film 2 also serves as a protective film for the polarizer 1a. The elliptically polarizing plate of the present invention is laminated so that the slow axis of the retardation film A and the absorption axis of the polarizer 1a are orthogonal to each other.

In elliptically polarizing plate shown in FIG. 1, the stacking order of the optical film 2 for the polarizer 1a, when mounted on the liquid crystal display device, from the point of suppressing deterioration and color shift contrast, polarizer 1a as in Fig. 1 From the above, it is preferable to laminate the retardation film A and the retardation film B in this order. 1 to 2, the polarizer 1a, the retardation film A, and the retardation film B are laminated via an adhesive layer or an adhesive layer. The pressure-sensitive adhesive layer or the adhesive layer may be a single layer, or may be a superposed form of two or more layers.

  In the retardation film A, the direction in which the in-plane refractive index is the maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction of the film is the Z axis. , Ny, and nz, those satisfying nx> ny≈nz are used. That is, in the three-dimensional refractive index ellipsoid, a material exhibiting optically positive uniaxiality in which the refractive index of the principal axis in one direction is larger than the refractive indexes in the other two directions is used.

  The retardation film A is obtained by subjecting a polymer film made of a thermoplastic polymer containing a cyclic polyolefin resin to uniaxial or biaxial stretching in the plane direction. Examples of the cyclic polyolefin resin include norbornene resins.

  Examples of the norbornene-based resin include (1) a ring-opening (co) polymer of a norbornene-based monomer, a polymer-modified product thereof such as maleic acid addition and cyclopentadiene addition, and a resin obtained by hydrogenating these; 2) Resin obtained by addition polymerization of norbornene monomer; (3) Resin obtained by addition copolymerization with norbornene monomer and olefin monomer such as ethylene and α-olefin. The polymerization method and the hydrogenation method can be performed by conventional methods.

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

  The norbornene-based resin can be used in combination with other cycloolefins capable of ring-opening polymerization within the range not impairing the object of the present invention. Specific examples of such cycloolefins include compounds having one reactive double bond such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.

  The norbornene-based resin has a number average molecular weight (Mn) of 25,000 to 200,000, preferably 30,000 to 100,000, more preferably measured by a gel permeation chromatograph (GPC) method using a toluene solvent. Is in the range of 40,000 to 80,000. When the number average molecular weight is in the above range, a material having excellent mechanical strength, good solubility, moldability, and casting operability can be obtained.

  When the norbornene-based resin is obtained by hydrogenating a ring-opening polymer of a norbornene-based monomer, a hydrogenation rate of 90% or more is usually used from the viewpoint of heat deterioration resistance, light deterioration resistance, and the like. It is done. Preferably it is 95% or more. More preferably, it is 99% or more.

  Specific examples of the film containing the norbornene-based resin include, for example, a ZEONOR film manufactured by Nippon Zeon Co., Ltd. and an ARTON film manufactured by JSR Corporation.

  The front phase difference ((nx−ny) × d (thickness: nm)) of the retardation film A is 50 to 210 nm, which is effective for suppressing reduction in contrast and improving color shift. The front phase difference is preferably 70 nm or more, more preferably 80 nm or more, and further preferably 90 nm or more. The front phase difference is preferably 200 nm or less, and more preferably 190 nm or less. The thickness (d) of the retardation film A is not particularly limited, but is preferably 1 to 200 μm, and more preferably 2 to 100 μm.

The phase difference film B is fixed in a homeotropic orientation. The direction in which the in-plane refractive index is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis. When the refractive index in the direction is nx ₁ , ny ₁ , nz ₁ , a material satisfying positive refractive index anisotropy (nz ₁ > nx ₁ ≈ny ₁ ) is used. The retardation film B is obtained, for example, by aligning a liquid crystal material with a vertical alignment agent. As a liquid crystal compound that can be homeotropically aligned, for example, a nematic liquid crystal compound is known. An outline of the liquid crystal compound alignment technique is described in, for example, Chemical Review 44 (Surface Modification, Edited by The Chemical Society of Japan, pages 156 to 163).

  The liquid crystal material includes, for example, a monomer unit (a) having a positive refractive index anisotropy and containing a liquid crystal fragment side chain and a monomer unit (b) containing a non-liquid crystal fragment side chain. It can be formed by a side chain type liquid crystal polymer. The side-chain liquid crystal polymer can realize homeotropic alignment of the liquid crystal polymer without using a vertical alignment film.

  The monomer unit (a) has a side chain having nematic liquid crystallinity, for example, the general formula (a):

（ただし、Ｒ¹は水素原子またはメチル基を、ａは１〜６の正の整数を、Ｘ¹は−ＣＯ₂−基または−ＯＣＯ−基を、Ｒ²はシアノ基、炭素数１〜６のアルコキシ基、フルオロ基または炭素数１〜６のアルキル基を、ｂおよびｃは１または２の整数を示す。）で表されるモノマーユニットがあげられる。

(Wherein R ¹ represents a hydrogen atom or a methyl group, a represents a positive integer of 1 to 6, X ¹ represents a —CO ₂ — group or —OCO— group, R ² represents a cyano group, and has 1 to 6 carbon atoms. An alkoxy group, a fluoro group, or an alkyl group having 1 to 6 carbon atoms, and b and c each represent an integer of 1 or 2.).

  The monomer unit (b) has a linear side chain. For example, the monomer unit (b) has the general formula (b):

（ただし、Ｒ³は水素原子またはメチル基を、Ｒ⁴は炭素数１〜２２のアルキル基、炭素数１〜２２のフルオロアルキル基、または一般式（ｂ１）：

(However, the R ³ is a hydrogen atom or a methyl group, R ⁴ is an alkyl group having 1 to 22 carbon atoms, fluoroalkyl group having 1 to 22 carbon atoms, or the general formula, (b1):

ただし、ｄは１〜６の正の整数を、Ｒ⁵は炭素数１〜６のアルキル基を示す。）で表されるモノマーユニットがあげられる。

However, d is a positive integer from 1 to 6, R ⁵ represents an alkyl group having 1 to 6 carbon atoms. ) Monomer units.

  Further, the ratio of the monomer unit (a) to the monomer unit (b) is not particularly limited and varies depending on the type of the monomer unit. However, when the ratio of the monomer unit (b) is increased, the side chain type liquid crystal polymer is changed. In order to stop showing liquid crystal monodomain orientation, it is preferable to set it as (b) / {(a) + (b)} = 0.01-0.8 (molar ratio). In particular, 0.1 to 0.5 is more preferable.

  The liquid crystal polymer capable of forming a homeotropic alignment liquid crystal film includes a monomer unit (a) containing the liquid crystalline fragment side chain and a monomer unit (c) containing a liquid crystalline fragment side chain having an alicyclic ring structure. And a side chain type liquid crystal polymer.

  The monomer unit (c) has a side chain having nematic liquid crystallinity, for example, the general formula (c):

（ただし、Ｒ⁶水素原子またはメチル基を、ｈは１〜６の正の整数を、Ｘ²は−ＣＯ₂−基または−ＯＣＯ−基を、ｅとｇは１または２の整数を、ｆは０〜２の整数を、Ｒ⁷はシアノ基、炭素数１〜１２のアルキル基を示す。）で表されるモノマーユニットがあげられる。

(Provided that the R ⁶ hydrogen atom or a methyl group, h is 1 to 6 positive integer, X ² is -CO ₂ - group or -OCO- group, e and g is 1 or 2 an integer, f Represents an integer of 0 to 2, and R ⁷ represents a cyano group and an alkyl group having 1 to 12 carbon atoms.).

  Further, the ratio of the monomer unit (a) to the monomer unit (c) is not particularly limited and varies depending on the type of the monomer unit. However, when the ratio of the monomer unit (c) is increased, the side chain type liquid crystal polymer is changed. Since the liquid crystal monodomain orientation is not exhibited, it is preferable that (c) / {(a) + (c)} = 0.01 to 0.8 (molar ratio). In particular, 0.1 to 0.6 is more preferable.

  The liquid crystal polymer that can form the retardation film B is not limited to those having the above-exemplified monomer units, and the exemplary monomer units can be appropriately combined.

  The side chain type liquid crystal polymer preferably has a weight average molecular weight (GPC) of 2,000 to 100,000. By adjusting the weight average molecular weight to such a range, performance as a liquid crystal polymer is exhibited. When the weight average molecular weight of the side chain type liquid crystal polymer is too small, the film forming property of the alignment layer tends to be poor. Therefore, the weight average molecular weight is more preferably 2.5000 or more. On the other hand, if the weight average molecular weight is excessive, the orientation as a liquid crystal tends to be poor and it becomes difficult to form a uniform alignment state. Therefore, the weight average molecular weight is more preferably 50,000 or less.

  The illustrated side chain type liquid crystal polymer can be prepared by copolymerizing an acrylic monomer or a methacrylic monomer corresponding to the monomer unit (a), the monomer unit (b), and the monomer unit (c). The monomers corresponding to the monomer unit (a), the monomer unit (b), and the monomer unit (c) can be synthesized by a known method. The copolymer can be prepared, for example, according to a polymerization method such as a conventional acrylic monomer such as a radical polymerization method, a cationic polymerization method, and an anionic polymerization method. When applying the radical polymerization method, various polymerization initiators can be used. Among them, decomposition temperatures such as azobisisobutyronitrile and benzoyl peroxide are not high and are not low. Those are preferably used.

  The side-chain liquid crystal polymer can be used as a liquid crystal composition by blending a photopolymerizable liquid crystal compound. The photopolymerizable liquid crystal compound is a liquid crystal compound having at least one unsaturated double bond such as an acryloyl group or a methacryloyl group as a photopolymerizable functional group, and a nematic liquid crystal compound is awarded. Examples of such photopolymerizable liquid crystal compounds include acrylates and methacrylates that serve as the monomer unit (a). As the photopolymerizable liquid crystal compound, those having two or more photopolymerizable functional groups are preferable for improving durability. As such a photopolymerizable liquid crystal compound, for example,

（式中、Ｒは水素原子またはメチル基を、ＡおよびＤはそれぞれ独立して１，４−フェニレン基または１，４−シクロヘキシレン基を、Ｘはそれぞれ独立して−ＣＯＯ−基、−ＯＣＯ−基または−Ｏ−基を、Ｂは１，４−フェニレン基、１，４−シクロヘキシレン基、４，４’−ビフェニレン基または４，４’−ビシクロヘキシレン基を、ｍおよびｎはそれぞれ独立して２〜６の整数を示す。）で表される架橋型ネマチック性液晶モノマー等を例示できる。また、光重合性液晶化合物としては、前記化５における末端の「Ｈ₂Ｃ＝ＣＲ−ＣＯ₂−」を、ビニルエーテル基またはエポキシ基に置換した化合物や、「−（ＣＨ₂）_m−」および／または「−（ＣＨ₂）_n−」を「−（ＣＨ₂）₃−Ｃ^*Ｈ（ＣＨ₃）−（ＣＨ₂）₂−」または「−（ＣＨ₂）₂−Ｃ^*Ｈ（ＣＨ₃）−（ＣＨ₂）₃−」に置換した化合物を例示できる。

(In the formula, R is a hydrogen atom or a methyl group, A and D are each independently 1,4-phenylene group or 1,4-cyclohexylene group, and X is each independently a —COO— group or —OCO group. -Group or -O- group, B is 1,4-phenylene group, 1,4-cyclohexylene group, 4,4'-biphenylene group or 4,4'-bicyclohexylene group, and m and n are each And a cross-linked nematic liquid crystal monomer represented by the following formula: Examples of the photopolymerizable liquid crystal compound include compounds in which the terminal “H ₂ C═CR—CO ₂ —” in Chemical Formula 5 is substituted with a vinyl ether group or an epoxy group, “— (CH ₂ ) _m —” and / Or “— (CH ₂ ) _n —” is replaced with “— (CH ₂ ) ₃ —C ^* H (CH ₃ ) — (CH ₂ ) ₂ —” or “— (CH ₂ ) ₂ —C ^* H (CH ₃ )-(CH ₂ ) ₃ — ”.

  The photopolymerizable liquid crystal compound can be converted into a liquid crystal state by heat treatment, for example, by developing a nematic liquid crystal layer and homeotropically aligning with the side chain type liquid crystal polymer, and then polymerizing or crosslinking the photopolymerizable liquid crystal compound. As a result, the durability of the homeotropic alignment liquid crystal film can be improved.

  The ratio of the photopolymerizable liquid crystal compound and the side chain type liquid crystal polymer in the liquid crystal composition is not particularly limited and is appropriately determined in consideration of the durability of the obtained homeotropic alignment liquid crystal film. Photopolymerizable liquid crystal compound: side chain type liquid crystal polymer (weight ratio) = about 0.1: 1 to 30: 1 is preferable, 0.5: 1 to 20: 1 is particularly preferable, and 1: 1 to 10: is more preferable. 1 is preferred.

  The liquid crystalline composition usually contains a photopolymerization initiator. Various photopolymerization initiators can be used without particular limitation. Examples of the photopolymerization initiator include Irgacure 907, 184, 651, and 369 manufactured by Ciba Specialty Chemicals. The addition amount of the photopolymerization initiator is added to such an extent that the homeotropic orientation of the liquid crystalline composition is not disturbed in consideration of the type of the photopolymerized liquid crystal compound, the blending ratio of the liquid crystalline composition, and the like. Usually, about 0.5-30 weight part is preferable with respect to 100 weight part of photopolymerizable liquid crystal compounds. Particularly preferred is 3 parts by weight or more.

  The retardation film B is produced by coating a homeotropic alignment side chain type liquid crystal polymer on a substrate, then aligning the side chain type liquid crystal polymer in a liquid crystal state and maintaining the alignment state. This is done by immobilization. When a homeotropic alignment liquid crystalline composition comprising the side chain liquid crystal polymer and the photopolymerizable liquid crystal compound is used, this is applied to a substrate, and then the liquid crystalline composition is homeomorphized in a liquid crystal state. A tropic alignment is performed, and light irradiation is performed while maintaining the alignment state.

  The substrate on which the side chain type liquid crystal polymer or liquid crystalline composition is applied may have any shape of a glass substrate, a metal foil, a plastic sheet, or a plastic film. The plastic film is not particularly limited as long as it does not change with the temperature at which it is oriented, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, polycarbonate polymers, Examples thereof include a film made of a transparent polymer such as an acrylic polymer such as polymethyl methacrylate. The vertical alignment film may not be provided on the substrate. The thickness of the substrate is usually about 10 to 1000 μm.

  The side chain type liquid crystal polymer or liquid crystal composition is applied to the substrate by a solution coating method using a solution obtained by dissolving the side chain type liquid crystal polymer or liquid crystal composition in a solvent, or the liquid crystal polymer or liquid crystal property. Although the method of melt | dissolving and melt-coating a composition is mentioned, Among these, the method of coating the solution of a side chain type liquid crystal polymer or a liquid crystalline composition on a support substrate by a solution coating method is preferable.

  Examples of the method for applying a solution of a side chain type liquid crystal polymer or liquid crystal composition adjusted to a desired concentration using the above-mentioned solvent on a substrate include a roll coating method, a gravure coating method, a spin coating method, A bar coat method or the like can be employed. After coating, the solvent is removed, and a liquid crystal polymer layer or a liquid crystal composition layer is formed on the substrate. The conditions for removing the solvent are not particularly limited, as long as the solvent can be generally removed and the liquid crystal polymer layer or the liquid crystal composition layer does not flow or even flow down. Usually, the solvent is removed by drying at room temperature, drying in a drying furnace, heating on a hot plate, or the like. Among these coating methods, the gravure coating method is preferably used in the present invention because it is easy to uniformly coat a large area.

  Next, the side chain type liquid crystal polymer layer or liquid crystal composition layer formed on the supporting substrate is brought into a liquid crystal state and homeotropically aligned. For example, heat treatment is performed so that the side chain type liquid crystal polymer or the liquid crystalline composition is in the liquid crystal temperature range, and homeotropic alignment is performed in the liquid crystal state. The heat treatment can be performed by the same method as the above drying method. The heat treatment temperature varies depending on the type of the side chain type liquid crystal polymer or liquid crystalline composition to be used and the support substrate, and cannot be generally stated, but is usually in the range of 60 to 300 ° C, preferably 70 to 200 ° C. The heat treatment time varies depending on the heat treatment temperature and the type of the side chain type liquid crystal polymer or liquid crystal composition or substrate used, but cannot be generally stated, but is usually in the range of 10 seconds to 2 hours, preferably 20 seconds to 30 minutes. Selected. If it is shorter than 10 seconds, homeotropic alignment formation may not proceed sufficiently. Among these orientation temperatures and treatment times, in the present invention, it is preferable from the viewpoint of workability and mass productivity that the treatment time is about 30 seconds to 10 minutes at an orientation temperature of 80 to 150 ° C.

  After the heat treatment is completed, a cooling operation is performed. As the cooling operation, the homeotropic alignment liquid crystal film after the heat treatment can be performed by taking it out from the heating atmosphere in the heat treatment operation to room temperature. Moreover, you may perform forced cooling, such as air cooling and water cooling. The orientation of the homeotropic alignment layer of the side chain type liquid crystal polymer is fixed by cooling to the glass transition temperature or lower of the side chain type liquid crystal polymer.

In the case of a liquid crystal composition, the homeotropic liquid crystal alignment layer thus fixed is irradiated with light, and the photopolymerizable liquid crystal compound is polymerized or crosslinked to fix the photopolymerizable liquid crystal compound, A homeotropic alignment liquid crystal film layer having improved durability is obtained. Light irradiation is performed by, for example, ultraviolet irradiation. The ultraviolet irradiation conditions are preferably in an inert gas atmosphere in order to sufficiently promote the reaction. Usually, a high-pressure mercury ultraviolet lamp having an illuminance of about 80 to 160 mW / cm ² is typically used. Different types of lamps such as metahalide UV lamps and incandescent tubes can also be used. It should be noted that the liquid crystal layer surface temperature at the time of ultraviolet irradiation is appropriately adjusted by, for example, a cold mirror, water cooling or other cooling treatment, or by increasing the line speed.

In this way, a thin film of a side chain type liquid crystal polymer or a liquid crystalline composition is produced, and the retardation film B is obtained by fixing it while maintaining the orientation. The thickness of the homeotropic alignment liquid crystal film of the present invention is not particularly limited, but the thickness of the homeotropic alignment liquid crystal film layer composed of the coated side chain liquid crystal polymer is about 0.3 to 200 μm, and more preferably 0.5. It is preferable to set it to -200 micrometers. If the thickness is 0.3 μm or less, the film thickness is too thin, making it difficult to control the thickness. When it exceeds 200 μm, when mounted on a liquid crystal display device, there are cases where there are directions in which the viewing angles of the upper, lower, left, and right sides widen, while conversely, narrowing directions may occur. The retardation film B can be used without being peeled off from the substrate.

  For the lamination of the retardation film A and the retardation film B, a pressure-sensitive adhesive layer or an adhesive layer can be used. The material for forming the pressure-sensitive adhesive layer or the adhesive layer is not particularly limited. For example, an acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is used as a base polymer. Can be appropriately selected and used. In particular, those having excellent optical transparency such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and being excellent in weather resistance, heat resistance and the like can be preferably used.

  The pressure-sensitive adhesive layer or the adhesive layer can be formed by an appropriate method. For example, a solution of about 10 to 40% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture such as toluene and ethyl acetate is prepared. A method of directly attaching on the substrate or the liquid crystal film by an appropriate development method such as a casting method or a coating method, or forming an adhesive layer or an adhesive layer on the separator according to the above, and placing it on the liquid crystal layer And a method of transferring to the surface.

  The pressure-sensitive adhesive layer or adhesive layer includes, for example, natural and synthetic resins, in particular, tackifier resins, fillers and pigments made of glass fiber, glass beads, metal powder, other inorganic powders, You may contain additives, such as a coloring agent and antioxidant. Moreover, you may contain microparticles | fine-particles and provide light diffusibility.

  The thickness of the pressure-sensitive adhesive layer or the adhesive layer can be appropriately determined according to the purpose of use or adhesive force, and is generally 1 to 500 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

  On the exposed surface of the pressure-sensitive adhesive layer or the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing its contamination until it is put to practical use. Thereby, it can prevent contacting an adhesive layer or an adhesive bond layer in a usual handling state. As the separator, except for the above thickness conditions, for example, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, laminate thereof, and the like, silicone type or Appropriate conventional ones such as those coated with an appropriate release agent such as long-chain alkyl, fluorine-based, or molybdenum sulfide can be used.

  In addition, each layer such as the optical film, the pressure-sensitive adhesive layer or the adhesive layer is made of an ultraviolet absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. The ultraviolet absorbing ability can be provided by a method such as a processing method.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymers such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. And polyene-based oriented films such as those obtained by adsorbing a volatile substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, those obtained by stretching a polyvinyl alcohol film and adsorbing and orienting a dichroic material (iodine, dye) are preferably used. The thickness of the polarizer is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring 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.

On one side of the polarizer, wherein at the optical film (the side of the retardation film A) is laminated, in the other side, usually with a protective film. The protective film is preferably used as a protective film for a polarizer, and has excellent transparency, mechanical strength, thermal stability, moisture shielding properties, isotropic properties, and the like. Examples of the material of the protective film include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene, acrylonitrile / styrene copolymers, and the like. Examples thereof include styrene polymers such as (AS resin) and polycarbonate polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Examples of polymers that form protective films include polymer blends. Other examples include films made of thermosetting or ultraviolet curable resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a thermoplastic resin having unsubstituted phenyl and a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  A protective film that can be particularly preferably used in terms of polarization characteristics and durability is a triacetylcellulose film whose surface is saponified with an alkali or the like. Although the thickness of a protective film can be determined suitably, generally it is about 10-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 20-300 micrometers is especially preferable, and 30-200 micrometers is more preferable.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

  The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of aqueous adhesives include polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, aqueous polyurethanes, aqueous polyesters, and the like.

  As the protective film, a hard coat layer, an antireflection treatment, an anti-sticking treatment, or a treatment subjected to diffusion or anti-glare treatment can be used.

  Hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, a cured film having excellent hardness and slipping properties with an appropriate ultraviolet curable resin such as acrylic or silicone is applied to the protective film. It can be formed by a method of adding to the surface. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the protective film by an appropriate method such as a blending method of transparent fine particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles made of a crosslinked or uncrosslinked polymer, etc. are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the protective film itself, or can be provided separately from the transparent protective layer as an optical layer.

  The elliptically polarizing plate of the present invention is suitably used for an IPS mode liquid crystal display device. An IPS mode liquid crystal display device includes a pair of substrates sandwiching a liquid crystal layer, an electrode group formed on one of the pair of substrates, and a liquid crystal composition material layer having dielectric anisotropy sandwiched between the substrates. A liquid crystal comprising: an alignment control layer formed opposite to the pair of substrates for aligning a molecular arrangement of the liquid crystal composition material in a predetermined direction; and a driving means for applying a driving voltage to the electrode group Has a cell. The electrode group has an arrangement structure arranged so as to apply an electric field mainly parallel to the interface between the alignment control layer and the liquid crystal composition material layer.

The elliptically polarizing plate of the present invention is disposed on at least one of the viewing side and the incident side of the liquid crystal cell. FIG. 3 shows a case where the elliptically polarizing plate of FIG. 1 is arranged on the viewing side. The elliptically polarizing plate as shown in Figure 3, you optical film 2 side to the liquid crystal cell LC side. In FIG. 3, a polarizing plate 1 ′ is disposed on the opposite side (light incident side) of the liquid crystal cell 4 on which the elliptically polarizing plate is disposed. The absorption axis of the polarizing plate 1 ′ arranged on both sides of the substrate of the liquid crystal cell LC and the absorption axis of the elliptical polarizing plate (polarizing plate 1) are arranged in an orthogonal state. As the polarizing plate 1 ', a laminate in which a protective film 1b is laminated on both sides of the polarizer 1a is usually used.

The liquid crystal display device of FIG. 3, Ru der shows an example of a liquid crystal cell.

  Examples of the present invention will be described below with reference to examples, but the present invention is not limited to the examples.

  The refractive index and retardation of each optical film are measured using the automatic birefringence measuring device (manufactured by Oji Scientific Instruments Co., Ltd., automatic birefringence meter KOBRA21ADH) using the main refractive indices nx, ny and nz in the film plane and in the thickness direction. ), The characteristics at λ = 590 nm were measured.

Reference example (polarizer)
The polyvinyl alcohol film was immersed in warm water to swell, then dyed in an iodine / potassium iodide aqueous solution, and then uniaxially stretched in an aqueous boric acid solution to obtain a polarizer. The polarizer was examined for single transmittance, parallel transmittance and orthogonal transmittance with a spectrophotometer. As a result, the transmittance was 43.5% and the polarization degree was 99.9%.

Example 1
(Phase difference film A)
A norbornene-based unstretched film having a thickness of 100 μm (Arton film manufactured by JSR) was uniaxially stretched 1.3 times at 170 ° C. The obtained stretched film had a thickness of 80 μm and a front phase difference of 100 nm. The obtained stretched film had a positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented.

  (Phase difference film B)

上記の化６（式中の数字はモノマーユニットのモル％を示し、便宜的にブロックポリマー体で示している、重量平均分子量５０００）で示される側鎖型液晶ポリマー５重量部、ネマチック液晶相を示す重合性液晶（Ｐａｌｉｏｃｏｌｏｒ ＬＣ２４２，ＢＡＳＦ製）２０重量部および光開始剤（イルガキュア９０７，チバスペシャルティケミカルズ社製）を前記重合性液晶に対して３重量部を、シクロへキサノン７５重量部に溶解した溶液を調製した。そして、当該溶液を、日本ゼオン社のゼオノアフィルム上にバーコーターにて塗布し、１００℃で１０分間、乾燥配向させた後、紫外線照射し、硬化することにより厚さ１．０μｍのホメオトロピック配向液晶フィルム層を得た。このサンプルの光学位相差を測定（測定光をサンプル表面に対して垂直あるいは斜めから入射）したところ、正面位相差がほぼゼロであり、また測定光の入射角度の増加に伴い位相差が増加したことからホメオトロピック配向が得られていることを確認した。ホメオトロピック配向液晶フィルム層の厚み方向位相差は、−１００ｎｍであった。

5 parts by weight of a side chain type liquid crystal polymer represented by the above chemical formula 6 (the number in the formula represents mol% of the monomer unit, and is represented by a block polymer for convenience), and a nematic liquid crystal phase. 20 parts by weight of a polymerizable liquid crystal (Paliocolor LC242, manufactured by BASF) and 3 parts by weight of a photoinitiator (Irgacure 907, manufactured by Ciba Specialty Chemicals) were dissolved in 75 parts by weight of cyclohexanone. A solution was prepared. Then, the solution is applied onto a ZEONOR film of Nippon Zeon Co., Ltd. with a bar coater, dried and oriented at 100 ° C. for 10 minutes, and then irradiated with ultraviolet rays and cured to give a homeotropic orientation of 1.0 μm in thickness. A liquid crystal film layer was obtained. When the optical phase difference of this sample was measured (measurement light was incident perpendicularly or obliquely to the sample surface), the front phase difference was almost zero, and the phase difference increased as the measurement light incident angle increased. From this, it was confirmed that homeotropic alignment was obtained. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was −100 nm.

(Ellipse polarizing plate)
A transparent protective layer is obtained by adhering a triacetyl cellulose (TAC) film having a thickness of 80 μm, a front phase difference of 6 nm, and a thickness direction retardation of 60 nm to one side of the polarizer obtained in the reference example via a polyvinyl alcohol adhesive. Formed. The other surface of the polarizer is bonded via a polyvinyl alcohol-based adhesive so that the absorption axis of the polarizer and the slow axis of the retardation film A are orthogonal to each other, and the retardation film B is adhered to the acrylic film on the adhesive film. Bonding was performed via an agent. Thereafter, the ZEONOR film was peeled off to obtain an elliptically polarizing plate.

Example 2
(Phase difference film A)
A norbornene-based unstretched film having a thickness of 100 μm (Arton film manufactured by JSR) was uniaxially stretched 1.4 times at 170 ° C. The obtained stretched film had a thickness of 70 μm and a front phase difference of 180 nm. The obtained stretched film had a positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented.

(Phase difference film B)
In Example 1, a homeotropic alignment liquid crystal film layer was obtained in the same manner as in Example 1 except that the thickness of the homeotropic alignment liquid crystal film layer was 0.5 μm. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was −50 nm.

(Ellipse polarizing plate)
In Example 1, an elliptically polarizing plate was obtained in the same manner as in Example 1 except that the retardation film A and the retardation film B were obtained as described above.

Example 3
(Phase difference film A)
A norbornene-based unstretched film having a thickness of 100 μm (Arton film manufactured by JSR) was uniaxially stretched 1.75 times at 175 ° C. The obtained stretched film had a thickness of 75 μm and a front phase difference of 140 nm. The obtained stretched film had a positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented.

(Phase difference film B)
In Example 1, a homeotropic alignment liquid crystal film layer was obtained in the same manner as in Example 1 except that the thickness of the homeotropic alignment liquid crystal film layer was 1.3 μm. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was -130 nm.

(Ellipse polarizing plate)
In Example 1, an elliptically polarizing plate was obtained in the same manner as in Example 1 except that the retardation film A and the retardation film B were obtained as described above.

Comparative Example 1
A transparent protective layer is obtained by adhering a triacetyl cellulose (TAC) film having a thickness of 80 μm, a front phase difference of 6 nm, and a thickness direction retardation of 60 nm to one side of the polarizer obtained in the reference example via a polyvinyl alcohol adhesive. Formed. A polarizing plate was obtained by bonding a triacetyl cellulose (TAC) film having a thickness of 80 μm, a front phase difference of 6 nm, and a thickness direction retardation of 60 nm to the other surface of the polarizer via a polyvinyl alcohol-based adhesive.

Comparative Example 2
A transparent protective layer is formed by adhering a triacetyl cellulose (TAC) film having a thickness of 40 μm, a front phase difference of 3 nm, and a thickness direction retardation of 40 nm to one side of the polarizer obtained in the reference example via a polyvinyl alcohol adhesive. Formed. A triacetyl cellulose (TAC) film having a thickness of 40 μm, a front phase difference of 3 nm, and a thickness direction retardation of 40 nm is bonded to the other surface of the polarizer via a polyvinyl alcohol adhesive. Thus, a polarizing plate was obtained.

Comparative Example 3
(Retardation film A ')
A polycarbonate film having a thickness of 80 μm was uniaxially stretched 1.3 times at 175 ° C. The obtained stretched film had a thickness of 50 μm and a front phase difference of 300 nm. The obtained stretched film had a positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented.

(Phase difference film B)
In Example 1, a homeotropic alignment liquid crystal film layer was obtained in the same manner as in Example 1 except that the thickness of the homeotropic alignment liquid crystal film layer was 3.0 μm. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was −300 nm.

(Ellipse polarizing plate)
In Example 1, an elliptically polarizing plate was used in the same manner as in Example 1 except that the retardation film A ′ and the retardation film B obtained above were used instead of the retardation film A, respectively. Got.

(Evaluation)
The following evaluation was performed about the elliptically polarizing plate or polarizing plate obtained above. The results are shown in Table 1.

(Viewing angle)
As shown in FIG. 3, the elliptically polarizing plates obtained in Examples 1 to 3 were arranged on the viewing side of the IPS mode liquid crystal cell. The polarizing plates obtained in Comparative Examples 1 and 2 were arranged on the viewing side of the IPS mode liquid crystal cell as shown in FIG. The elliptically polarizing plate obtained in Comparative Example 3 was used in place of the elliptically polarizing plate used in Example 1. On the other hand, the polarizing plate obtained in Comparative Example 1 was disposed on the incident side (backlight side).

  A white image and a black image are displayed on the liquid crystal display device, and Y in the XYZ display system in the vertical and horizontal directions, 45 ° to 225 ° diagonal, and 135 ° to 315 ° diagonal in EZcontrast 160D manufactured by ELDIM. Value, x value, y value were measured. The angle at which the contrast (Y value (white image) / Y value (black image)) at that time was 25 or more was defined as the viewing angle.

(Unevenness due to bonding stress)
The elliptically polarizing plate or polarizing plate (400 mm × 300 mm) obtained above was bonded to alkali glass with an acrylic pressure-sensitive adhesive (20 μm) so as to be crossed Nicol using a roller. Unevenness due to stress after bonding was visually confirmed on the following criteria after irradiation of the backlight.
○: No light was detected.
X: Light loss was confirmed.

(Heating durability)
The elliptically polarizing plate or polarizing plate (300 mm × 200 mm) obtained above is pressure-bonded to alkali glass with an acrylic adhesive (20 μm) so as to be crossed Nicol, and then at 50 ° C., 5 atm, 15 minutes. Air bubbles were removed by autoclaving, and the peripheral unevenness after 100 hours in an 80 ° C. environment was visually confirmed on the basis of the following criteria after irradiation with the backlight.
○: No light was detected.
X: Light loss was confirmed.

It is one mode of a sectional view and a conceptual diagram of an elliptically polarizing plate of the present invention. The present invention is an embodiment of a cross-sectional view and a conceptual diagram of an elliptically polarizing plate in which the positions of the retardation films A and B are different . 1 is an embodiment of a conceptual diagram of a liquid crystal display device of the present invention. It is an aspect of the conceptual diagram of the liquid crystal display device of a comparative example.

Explanation of symbols

A: nx> ny ≒ nz, the phase difference satisfying the film _{B: nz 1> nx 1 ≒} ny 1, the retardation film 1a satisfies: polarizer 2: optical films LC: liquid crystal cell

Claims (6)

It consists of a thermoplastic polymer containing a cyclic polyolefin resin. The direction in which the in-plane refractive index is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis. Retardation film A having positive refractive index anisotropy (nx> ny≈nz) uniaxially oriented when the refractive index is nx, ny, nz;
The direction in which the in-plane refractive index is maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis. The refractive index in each axial direction is nx. ₁ , ny ₁ , nz ₁ , an optical film formed by laminating a retardation film B having positive refractive index anisotropy (nz ₁ > nx ₁ ≈ny ₁ ),
It is an elliptically polarizing plate laminated on one side of the polarizer so that the slow axis of the retardation film A and the absorption axis of the polarizer are orthogonal to each other,
The elliptical polarizing plate is laminated with an optical film so as to be in the order of a retardation film A and a retardation film B from a polarizer .
The polarizer and the retardation film A are laminated by an adhesive layer,
The elliptically polarizing plate is used in a liquid crystal display device of a transverse electric field type (IPS mode) so that the optical film side is a liquid crystal cell side.   The elliptically polarizing plate according to claim 1, wherein the retardation film A is a film containing a norbornene resin. The retardation film B has a thickness direction retardation: {((nx ₁ + ny ₁ ) / 2) −nz ₁ } × d (thickness: nm) of −500 nm to −10 nm. Item 3. The elliptically polarizing plate according to item 1 or 2 . The retardation film B is a film containing a side chain type liquid crystal polymer, The elliptically polarizing plate according to any one of claims 1 to 3 . The retardation film A is a λ / 4 plate, The elliptically polarizing plate according to any one of claims 1 to 4 . A liquid crystal display device having a transverse electric field mode (IPS mode) as a drive mode, wherein the elliptically polarizing plate according to any one of claims 1 to 5 is laminated.

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