KR100814311B1 - Elliptical polarizing plate and image display - Google Patents

Abstract

The elliptical polarizing plate of the present invention is made of a thermoplastic polymer containing a cyclic polyolefin resin, each having a maximum refractive index in the plane of the X axis, a direction perpendicular to the X axis, a Y axis, and a thickness direction of the Z axis, respectively. When the refractive index in the axial direction of nx is nx, ny, or nz, the phase difference film A having positive refractive index anisotropy (nx> ny ≒ nz) uniaxially oriented is fixed to the homeotropic orientation, and the in-plane refractive index is Positive refractive index anisotropy when the maximum direction is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis, and the refractive indexes in the respective axial directions are nx ₁ , ny ₁ , and nz ₁ . there is an optical film obtained by laminating a retardation film B having ₍₁ nz> nx ≒ ny _{1 1),} is laminated on one side of a polarizer, an absorption axis of the retardation film a of the polarizer and the slow axis to be orthogonal. When applied to an active matrix liquid crystal display device of a transverse electric field system, such an elliptical polarizing plate can suppress the fall of contrast in a wide viewing angle, and has a high effect of improving color shift.

Elliptical polarizing plate, image display device, liquid crystal display device

Description

Elliptical polarizer and image display device {ELLIPTICAL POLARIZING PLATE AND IMAGE DISPLAY}

This invention relates to the elliptical polarizing plate which laminated | stacked the optical film which laminated | stacked the retardation film, and the polarizer. The elliptical polarizing plate of the present invention is suitable for an active matrix liquid crystal display device of a transverse electric field system (IPS mode).

Conventionally, as a liquid crystal display device, the so-called TN mode liquid crystal display device in which the liquid crystal having positive dielectric anisotropy is twisted horizontally aligned between bases facing each other is mainly used. However, in the TN mode, even if black display is to be performed due to its driving characteristics, birefringence occurs due to liquid crystal molecules in the vicinity of the substrate. As a result, light leakage occurs and it is difficult to perform full black display. On the other hand, the transverse electric field type liquid crystal display device performs pixel display by forming an electric field parallel to the liquid crystal substrate between the pixel electrode and the common electrode, and compares it with the TN mode method of forming an electric field perpendicular to the substrate. There is an advantage that black display is possible and a wide viewing angle is obtained.

However, in the conventional transverse electric field type active matrix liquid crystal display device, although a substantially black display is possible in the panel normal line direction, when observing a panel in a direction displaced from the normal line direction, the polarizing plates are disposed above and below the liquid crystal cell. As a result of unavoidable light leakage due to the characteristics of the polarizing plate in the direction deviated from the optical axis direction, the viewing angle was narrowed, resulting in a decrease in contrast. Moreover, when it observes from a diagonal direction, the optical path of light becomes long and the apparent retardation of a liquid crystal layer changes. For this reason, when the viewing angle is changed, a change occurs in the wavelength of transmitted light, the color of the screen changes, and a color shift occurs depending on the viewing direction.

Various proposals are made | formed in order to suppress suppression of contrast fall and color shift which depend on the viewing angle in the liquid crystal display device of such a transverse electric field system (patent document 1, patent document 2). For example, in patent document 1, the technique of interposing the compensation layer which has optical anisotropy between a liquid crystal layer and a pair of polarizing plate which sandwiches this is proposed. This technique is effective for improving color shift, but suppressing the decrease in contrast is not sufficient. Moreover, in patent document 2, the technique which interposes a 1st and 2nd phase difference plate between a liquid crystal layer and a pair of polarizing plate which sandwiches this is proposed. In this technique, although it is described that it is effective for suppressing contrast fall and improving color shift, higher improvement effect is calculated | required.

Patent Document 1: Japanese Patent Application Laid-Open No. 11-133408

Patent Document 2: Japanese Patent Application Laid-Open No. 2001-242462

Disclosure of the Invention

Problems to be Solved by the Invention

INDUSTRIAL APPLICABILITY The present invention is an elliptical polarizing plate in which a retardation film and a polarizer are laminated. The present invention is applied to an active matrix liquid crystal display device of a transverse electric field system, which can suppress a decrease in contrast at a wide viewing angle, and further improve the color shift. It aims to provide high.

Moreover, an object of the present invention is to provide an active matrix liquid crystal display device of a transverse electric field system which can suppress the decrease in contrast in a wide viewing angle and has a high effect of improving color shift by using the elliptical polarizing plate. do.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventor discovered that the said objective can be achieved by the elliptical polarizing plate shown below, and came to complete this invention.

That is, this invention consists of a thermoplastic polymer containing cyclic polyolefin resin, The direction which makes the in-plane refractive index maximum is the X-axis, the direction perpendicular | vertical to the X-axis, Y-axis, and the thickness direction Z-axis, respectively Retardation film A which has positive refractive index anisotropy (nx> ny ≒ nz) when uniaxially oriented when the refractive index of a direction is set to nx, ny, and nz, and

It is fixed to the homeotropic orientation, and the direction in which the in-plane refractive index is maximized is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis, and the refractive indices of the respective axial directions are nx ₁ , ny _In the case where ₁ , nz ₁ , the optical film obtained by laminating the retardation film B having positive refractive anisotropy (nz ₁ > nx ₁ ) ny ₁ ) is absorbed by the slow axis of the retardation film A and the polarizer on one side of the polarizer. Elliptical polarizing plates are stacked such that the axes are perpendicular to each other,
In the elliptically polarizing plate, optical films are laminated so as to be in the order of retardation film A and retardation film B from the polarizer,
The polarizer and the retardation film A are laminated by an adhesive layer,
The elliptical polarizing plate is an elliptical polarizing plate which is used in a liquid crystal display device in which the driving mode is a transverse electric field system (IPS mode) so that the optical film side is the liquid crystal cell side.

Retardation film A and retardation film B are laminated | stacked on the elliptically polarizing plate of the said invention. The retardation film A has a compensation function by positive refractive index anisotropy oriented in the axial direction, and the retardation film B can also control the phase difference in the thickness direction. Thereby, the fall of contrast based on the axial change of the polarizer which arises by the change of a vision can be suppressed, a color shift can be improved and a wide viewing angle can be compensated.

Moreover, the retardation film A contains cyclic polyolefin resin. A cyclic polyolefin resin has a small photoelastic coefficient, and can suppress the nonuniformity which is easy to generate | occur | produce in tensile stress, a durability test, etc. especially in the use of large panels, such as a transverse electric field system (IPS mode).

Moreover, in the elliptically polarizing plate of this invention, retardation film A is laminated | stacked so that the slow axis may orthogonally cross the absorption axis of a polarizer. Arranged orthogonally as mentioned above is preferable at the point which obtains high contrast.

Moreover, since the optical film which laminated | stacked the retardation film A and the retardation film B is laminated | stacked on the polarizer, and the optical film also serves as a protective film, it can be thin and lightweight, can suppress the fall of contrast, and also provides the color shift. It is excellent in that it can improve.

The said elliptical polarizing plate is laminated | stacked in the optical film so that it may become the order of retardation film A and retardation film B from a polarizer, can suppress the fall of contrast in a wide viewing angle, and is preferable at the point of the improvement effect of a color shift. .

In the elliptical polarizing plate, as the retardation film A, it is preferable to use a film containing norbornene-based resin. The film containing norbornene-type resin is preferable at the point which is excellent in durability under high temperature, high temperature, high humidity conditions, etc.

In the above elliptical polarizing plate, the phase difference film B is a phase difference in the thickness direction in order to suppress a decrease in contrast and color shift at a wide viewing angle: {((nx ₁ + ny ₁ ) / 2) -nz ₁ } × d (thickness) : Nm) is preferably -500 nm to -10 nm. As for the retardation of the thickness direction of the said retardation film B, it is more preferable that they are -300 nm --30 nm. Moreover, -200-50 nm is more preferable.

In the elliptically polarizing plate, although the retardation film B can be used without any particular limitation, the film containing the side chain type liquid crystal polymer is preferable. In addition, as a material of retardation film B, the material from which the refractive index in surface direction of an extending direction becomes small, and what is called a negative optical material can be illustrated. Examples of such materials include styrene resins and acrylic resins.

(Lambda) / 4 plate can be used as retardation film A in the said elliptical polarizing plate.

The present invention also relates to an active matrix liquid crystal display device in which the elliptical polarizing plate is laminated, and the driving mode is a transverse electric field system (IPS mode). Image display apparatuses, such as a liquid crystal display device to which the said elliptical polarizing plate was applied, can realize wide viewing angle, and even when the display screen is viewed at an angle, the decrease in contrast can be suppressed and the color shift can be improved.

The liquid crystal display device can be formed by arranging the elliptical polarizing plate of the present invention on one side or both sides of the liquid crystal cell instead of the conventional polarizing plate. In the arrangement of the elliptical polarizing plate of the present invention with respect to the liquid crystal cell, the optical film obtained by laminating the retardation film A and the retardation film B is placed on the liquid crystal cell side (that is, the optical film is between the polarizer and the liquid crystal cell), and in the liquid crystal display device It is preferable for display quality that the said optical film is arrange | positioned between the polarizer arrange | positioned by cross nicol. In addition, although an elliptical polarizing plate is arrange | positioned at a metal electrode in an organic electroluminescence display, it is preferable to laminate | stack the polarizer in the position farthest from a liquid crystal cell or a metal electrode.

BRIEF DESCRIPTION OF THE DRAWINGS It is one aspect of sectional drawing and conceptual diagram of the elliptical polarizing plate of this invention.

FIG. 2: is an aspect of sectional drawing and conceptual diagram of the elliptical polarizing plate in which retardation film A, B position differs from this invention.

3 is an aspect of a conceptual diagram of the liquid crystal display device of the present invention.

4 is an aspect of a conceptual diagram of a liquid crystal display device of a comparative example.

(Explanation of the sign)

A: retardation film satisfying nx> ny ≒ nz

B: retardation film satisfying nz ₁ > nx ₁ ≒ ny ₁

1a: polarizer

2: optical film

LC: liquid crystal cell

Implement the invention  Best form for

Hereinafter, the elliptical polarizing plate of the present invention will be described with reference to FIG. 1. As shown in FIG. 1, in the elliptically polarizing plate of this invention, the optical film 2 in which the retardation film A and the retardation film B are laminated | stacked is laminated | stacked on the single side | surface of the polarizer 1a. In addition, 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 said optical film 2 serves as the protective film of the polarizer 1a. In addition, the elliptically polarizing plate of this invention is laminated | stacked so that the slow axis of retardation film A and the absorption axis of polarizer 1a may orthogonally cross.

In the elliptically polarizing plate shown in FIG. 1, the stacking order of the optical film 2 with respect to the polarizer 1a is a polarizer as in FIG. 1 in terms of suppressing a decrease in contrast and color shift when mounted on a liquid crystal display device. It is preferable to laminate | stack in order of retardation film A and retardation film B from (1a). In addition, in FIGS. 1-2, the polarizer 1a, the retardation film A, and the retardation film B are laminated | stacked through the adhesive layer or an adhesive bond layer. One layer may be sufficient as an adhesive layer or an adhesive bond layer, and it can be set as the superposition form of two or more layers.

In the retardation film A, the direction in which the refractive index in the film plane becomes 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, and the refractive indices of the respective axial directions are nx, ny, and nz. In this case, the one satisfying nx> ny ≒ nz is used. That is, in the three-dimensional refractive index ellipsoid, a material that exhibits optically positive uniaxiality in which the refractive index of the main axis in one direction is larger than the refractive index in the other two directions is used.

The retardation film A is obtained by uniaxially or biaxially stretching the polymer film made of a thermoplastic polymer containing a cyclic polyolefin resin in the plane direction. As cyclic polyolefin resin, norbornene-type resin is illustrated, for example.

Examples of the norbornene-based resin include (1) ring-opening (co) polymers of norbornene-based monomers, polymer modified substances such as maleic acid addition and cyclopentadiene addition, and resins hydrogenated these; (2) resins obtained by addition polymerization of norbornene-based monomers; (3) resins obtained by addition-type copolymerization with norbornene-based monomers and olefin-based monomers such as ethylene and α-olefins. A polymerization method and a hydrogenation method can be performed by a conventional method.

As the norbornene-based monomer, for example, norbornene and its alkyl and / or alkylidene substituents, for example 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5- Polar group substituents such as halogen such as ethyl-2-norbornene, 5-butyl-2-norbornene and 5-ethylidene-2-norbornene; Dicyclopentadiene, 2,3-dihydrodicyclopentadiene and the like; Polar group substituents such as dimethanooctahydronaphthalene, alkyl and / or alkylidene substituents and halogens thereof, for example 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-octahydronaphthalene, 6-ethyl Liden-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- to 4-mers of cyclopentadiene, for example 4,9: 5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H-benzoindene, 4 , 11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentaanthracene and the like. Can be mentioned.

The said norbornene-type resin can use together the other cycloolefin type which can be ring-opened-polymerized in the range which does not impair the objective of this invention. As a specific example of such a cycloolefin, the compound which has one reactive double bond, such as cyclopentene, cyclooctene, 5, 6- dihydrodicyclopentadiene, is mentioned, for example.

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 40,000 to 80,000, as measured by gel permeation and chromatograph (GPC) method using a toluene solvent. It is a range. If the number average molecular weight is in the above range, one having excellent mechanical strength and having good solubility, moldability, and flexible operability can be produced.

When the norbornene-based resin is obtained by hydrogenating a ring-opening polymer of a norbornene-based monomer, the hydrogenation rate is usually 90% or more from the viewpoint of heat deterioration resistance, light deterioration resistance and the like. 95% or more is preferred. 99% or more is more preferable.

As a specific example of the film containing said norbornene-type resin, the zeona film by Nippon-Xeon company, the aton film by JSR company, etc. are mentioned, for example.

It is effective for the front retardation ((nx-ny) x d (thickness: nm)) of the retardation film A to be 50-210 nm for suppression of contrast fall and improvement of a coli shift. The said front phase difference is 70 nm or more, 80 nm or more is more preferable, It is still more preferable that it is 90 nm or more. Moreover, the said front phase difference is 200 nm or less, and 190 nm or less is more preferable. Although the thickness (d) of retardation film A is not specifically limited, 1-200 micrometers is preferable and 2-100 micrometers is more preferable.

The retardation film B is fixed in homeotropic orientation, and the refractive index of each axis direction is set to the X axis | shaft, the direction perpendicular | vertical to the X axis | shaft, the Y axis | shaft, and the thickness direction Z axis | shaft to which the in-plane refractive index becomes the largest, When is set to nx ₁ , ny ₁ , and nz ₁ , it is used to satisfy positive refractive index anisotropy (nz ₁ > nx ₁ ? Ny ₁ ). Retardation film B is obtained by orienting a liquid crystal material with a vertical alignment agent, for example. As a liquid crystal compound which can be homeotropically oriented, the nematic liquid crystal compound is known, for example. The outline related to the orientation technique of such a liquid crystal compound is described, for example in Chemical Summary 44 (Surface Modification, Nippon Chemical Society, pages 156 to 163).

Moreover, as said liquid-crystal material, the side chain type liquid crystal polymer containing the monomer unit (a) containing the liquid crystalline fragment side chain which has positive refractive index anisotropy, and the monomer unit (b) containing a non-liquid crystalline fragment side chain, for example. It can form by. The side chain type 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):

(Wherein R ¹ is a hydrogen atom or a methyl group, a is a positive integer of 1 to 6, X ¹ is a -CO ₂ -group or an -OCO- group, R ² is a cyano group or an alkoxy group having 1 to 6 carbon atoms) , A fluorine group or an alkyl group having 1 to 6 carbon atoms, b and c represent an integer of 1 or 2.

In addition, a monomer unit (b) has a linear side chain, For example, General formula (b):

(Wherein R ³ is a hydrogen atom or a methyl group, R ⁴ is a C1-C22 alkyl group, a C1-C22 fluoroalkyl group, or general formula (b1):

And a monomer unit represented by (wherein d represents a positive integer of 1 to 6 and R ⁵ represents an alkyl group having 1 to 6 carbon atoms).

In addition, the ratio of the monomer unit (a) and 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 has a liquid crystal monodomain alignment property. Since cannot be represented, it is preferable to set (b) / {(a) + (b) = 0.01 to 0.8 (molar ratio). It is more preferable to set it as especially 0.1-0.5.

Moreover, as a liquid crystal polymer which can form a homeotropic aligning liquid crystal film, it contains the monomer unit (a) containing the said liquid crystalline fragment side chain, and the monomer unit (c) containing the liquid crystalline fragment side chain which has an alicyclic cyclic structure. The side chain type liquid crystalline polymer mentioned can be mentioned.

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

(Where, R ⁶ a hydrogen atom or a methyl group, h is a positive integer of 1~6, X ² is -CO ₂ - group or an integer from -OCO-, e and g is 1 or 2, f is 0 The monomer unit represented by the integer of -2 to R <^7> represents a cyano group and a C1-C12 alkyl group.) Is mentioned.

Moreover, although the ratio of a monomer unit (a) and a monomer unit (c) is not restrict | limited in particular, It changes with kinds of monomer units, When a ratio of monomer unit (c) becomes high, a side chain type liquid crystal polymer will have liquid-crystal monodomain orientation. Since it cannot be represented, it is preferable to set (c) / {(a) = (c)} = 0.01 to 0.8 (molar ratio). In particular, it is more preferable to set it as 0.1-0.6.

The liquid crystal polymer which can form retardation film B is not limited to what has the monomer unit illustrated above, The said monomer unit can be combined suitably.

It is preferable that the weight average molecular weights (GPC) of the said side chain type liquid crystal polymer are 2000-100,000. By adjusting a weight average molecular weight in this range, the performance as a liquid crystal polymer is exhibited. When the weight average molecular weight of a side chain type liquid crystal polymer is too small, since there exists a tendency for the film formation property of an orientation layer to fall, it is more preferable to set it as 2.5 thousand or more. On the other hand, when the weight average molecular weight is excessive, since the orientation as a liquid crystal is insufficient and it becomes difficult to form a uniform orientation state, it is more preferable that a weight average molecular weight shall be 50,000 or less.

Moreover, the above-mentioned side chain type liquid crystal polymer can be prepared by copolymerizing the acryl-type monomer or methacryl-type monomer corresponding to the said monomer unit (a), a monomer unit (b), and a monomer unit (c). In addition, the monomer corresponding to a monomer unit (a), a monomer unit (b), and a monomer unit (c) can be synthesize | combined by a well-known method. Preparation of a copolymer can be performed according to polymerization systems, such as conventional acrylic monomers, such as a radical polymerization system, a cationic polymerization system, and an anion polymerization system, for example. In addition, in the case of applying the radical polymerization method, various polymerization initiators can be used, but among them, it is preferable to decompose at an intermediate temperature at which the decomposition temperature of azobisisobutyronitrile or benzoyl peroxide is neither high nor low. do.

A photopolymerizable liquid crystal compound can be mix | blended with the said side chain type liquid crystal polymer, and can be used as a liquid crystalline composition. As a photopolymerizable functional group, a photopolymerizable liquid crystal compound is a liquid crystalline compound which has at least 1 unsaturated double bond, such as an acryloyl group or a methacryloyl group, and a nematic liquid crystalline compound is common. As such a photopolymerizable liquid crystal compound, the acrylate and methacrylate which become the said monomer unit (a) can be illustrated. As a photopolymerizable liquid crystal compound, in order to improve durability, it is preferable to have two or more photopolymerizable functional groups. As such a photopolymerizable liquid crystal compound, for example, the following Chemical Formula 5:

(Wherein R is a hydrogen atom or a methyl group, A and D are each independently a 1,4-phenylene group or a 1,4-cyclohexylene group, and X is each independently a -COO- group, -OCO- group or -O- group, B is 1,4-phenylene group, 1,4-cyclohexylene group, 4,4'-biphenylene group or 4,4'-bicyclohexylene group, m and n are each independently 2 The integer of -6 is shown.) The crosslinking nematic liquid crystal monomer etc. which are represented by can be illustrated. Further, as the photo-polymerizable liquid crystal compound, _{'H 2 C = CR-CO 2} - "of the terminal according to the general formula (5) are substituted for by vinyl ether group or an epoxy compound and" - (CH _{2) m} - "and / or ``-(CH <sub>2</sub> ) <sub>n-</sub> '' is represented by ``-(CH ₂ ) ₃ -C ^* H (CH ₃ )-(CH ₂ ) _2- '' or ``-(CH ₂ ) ₂ -C ^* H (CH ₃ )- (CH _{2) 3} - ", there can be mentioned a substituted compound with.

The photopolymerizable liquid crystal compound can be homeotropically oriented with a side chain type liquid crystal polymer by, for example, expressing a nematic liquid crystal layer as a liquid crystal state by heat treatment, and then homeo by polymerizing or crosslinking the photopolymerizable liquid crystal compound. The durability of the tropic 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 oriented liquid crystal film and the like, but is usually a photopolymerizable liquid crystal compound: a side chain type liquid crystal polymer ( Weight ratio) = 0.1: 1-30: 1 are preferable, 0.5: 1-20: 1 are especially preferable, and 1: 1-10: 1 are more preferable.

In the said liquid crystalline composition, a photoinitiator is normally contained. Various types of photoinitiators can be used without particular limitation. As a photoinitiator, Irgacure907, 184, 651, 369 etc. by the Chiba Specialty Chemicals company can be illustrated, for example. The addition amount of a photoinitiator is added to such an extent that the homeotropic alignment property of a liquid crystalline composition is not disturbed in consideration of the kind of photopolymerization liquid crystal compound, the compounding ratio of a liquid crystalline composition, etc. Usually, about 0.5-30 weight part is preferable with respect to 100 weight part of photopolymerizable liquid crystal compounds. 3 weight part or more is especially preferable.

Preparation of the retardation film B coats a homeotropic oriented side chain type liquid crystal polymer on a board | substrate, and then makes the said side chain type liquid crystal polymer homeotropically align in a liquid crystal state, and fixes it in the state which maintained the orientation state. Conduct. In addition, when using the homeotropic oriented liquid crystalline composition containing the said side chain type liquid crystal polymer and a photopolymerizable liquid crystal compound, after coating this to a board | substrate, the said liquid crystalline composition is homeotropically aligned in a liquid crystal state, It carries out by irradiating light in the state which maintained the orientation state.

The board | substrate which coats the said side chain type liquid crystal polymer or liquid crystalline composition may be 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 at the temperature to be oriented. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, and polycarbonate polymers. And films made of transparent polymers such as acrylic polymers such as polymethyl methacrylate. The vertical alignment film does not need to be formed on the substrate. The thickness of a board | substrate is about 10-1000 micrometers normally.

The method of coating the side chain type liquid crystal polymer or liquid crystalline composition on a substrate is a solution coating method using a solution obtained by dissolving the side chain type liquid crystal polymer or liquid crystalline composition in a solvent or melting and coating the liquid crystal polymer or liquid crystalline composition. Although a method 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 the solution coating method is preferable.

As a method of coating the solution of the side chain type | mold liquid crystal polymer or liquid crystalline composition adjusted to the desired density | concentration using said solvent on a board | substrate, for example, the roll coat method, the gravure coat method, the spin coat method, the bar coat method, etc. Can be adopted. After coating, a solvent is removed and a liquid crystal polymer layer or a liquid crystalline composition layer is formed on a board | substrate. The removal conditions of a solvent are not specifically limited, A solvent can be removed substantially, and a liquid crystal polymer layer or a liquid crystalline composition does not need to flow or flow off. Usually, a solvent is removed using drying at room temperature, drying in a drying furnace, heating on a hot plate, and the like. Among these coating methods, in the present invention, it is preferable to employ the gravure coat method in that it is easy to coat a large area uniformly.

Next, the side chain type liquid crystal polymer layer or liquid crystal composition layer formed on the support substrate is brought into a liquid crystal state, and homeotropic alignment is performed. For example, heat processing is performed so that a side chain type liquid crystal polymer or liquid crystalline composition may become a liquid crystal temperature range, and homeotropic alignment is carried out in a liquid crystal state. As a heat processing method, it can carry out by the method similar to said drying method. Since heat processing temperature changes with kinds of the side chain type liquid crystal polymer or liquid crystalline composition and support substrate to be used, although it cannot say collectively, it carries out normally in 60-300 degreeC, Preferably it is 70-200 degreeC. In addition, since heat processing time changes with heat processing temperature and the kind of side chain type liquid crystal polymer or liquid crystalline composition and board | substrate to be used, although it cannot say collectively, it is 10 second-2 hours normally, Preferably it is 20 second-30 It is selected in the range of minutes. When it is shorter than 10 second, there exists a possibility that homeotropic orientation formation may not fully advance. Among these orientation temperatures and the treatment time, in the present invention, it is preferable to perform the treatment time for about 30 seconds to 10 minutes at the orientation temperature of 80 to 150 ° C in view of workability and mass productivity.

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

In the case of the liquid crystal composition, homeotropic irradiation is performed on the homeotropic liquid crystal alignment layer fixed in this manner, and the photopolymerizable liquid crystal compound is fixed by polymerizing or crosslinking the photopolymerizable liquid crystal compound to improve durability. An orientation liquid crystal film layer is obtained. Light irradiation is performed by self-irradiation, for example. It is preferable to make ultraviolet irradiation conditions into inert gas atmosphere, in order to fully promote reaction. Usually, a high pressure mercury ultraviolet lamp having an illuminance of about 80 to 160 mW / cm 2 is typically used. Other types of lamps, such as metahalide UV lamps or incandescent tubes, can also be used. Moreover, it adjusts suitably by quickening a cold mirror, water cooling, other cooling processes, or line speed so that the liquid-crystal layer surface temperature at the time of ultraviolet irradiation may be in a liquid crystal temperature range.

In this way, the thin film of a side chain type liquid crystal polymer or a liquid crystalline composition is produced | generated, and the phase difference film B is obtained by fixing with the orientation maintained. Although the thickness in particular of the homeotropic oriented liquid crystal film of this invention is not restrict | limited, The thickness of the homeotropic oriented liquid crystal film layer which consists of the said side chain type liquid crystal polymer is about 0.3-200 micrometers, and it shall be 0.5-200 micrometers. More preferred. At 0.3 micrometer or less, since film thickness becomes too thin, thickness control is difficult. When it exceeds 200 micrometers, when mounted in an image display apparatus, there exists an orientation which widens the viewing angle of up, down, left, and right, and a direction narrowing on the contrary may arise. Retardation film B can be used, without peeling from a board | substrate or peeling.

An adhesive layer or an adhesive bond layer can be used for lamination | stacking of retardation film A and retardation film B. FIG. Although the material which forms an adhesive layer or an adhesive bond layer is not specifically limited, For example, it selects suitably what uses a polymer, such as an acryl-type polymer, a silicone type polymer, polyester, a polyurethane, a polyamide, a polyether, a fluorine type or a rubber type, as a base polymer. Can be used. In particular, an acrylic adhesive has excellent optical transparency, exhibits moderate wettability, cohesiveness, and adhesive adhesion characteristics, and can be preferably used with excellent weather resistance, heat resistance, and the like.

Formation of an adhesive layer or an adhesive bond layer can be performed by a suitable method. As an example, about 10 to 40weight% of the solution which melt | dissolved or disperse | distributed or disperse | distributed a base polymer or its composition in the solvent which consists of a single substance or mixture of the appropriate solvents, such as toluene and ethyl acetate, is prepared, for example, it is cast by the method and coating The method of laying directly on the said board | substrate or a liquid crystal film by appropriate development methods, such as a system, or the method of forming an adhesive layer or an adhesive bond layer on a separator according to the above, and transferring it to the said liquid crystal layer, etc. are mentioned.

In addition, additives, such as fillers, pigments, coloring agents, antioxidants, etc. which consist of resins of a natural or synthetic substance, especially tackifying resin, glass fiber, glass beads, metal powder, and other inorganic powders, are contained in an adhesive layer or an adhesive layer, for example. It may contain. Moreover, you may contain microparticles | fine-particles and may provide light diffusivity.

The thickness of an adhesive layer or an adhesive bond layer can be suitably determined according to a use purpose, adhesive force, etc., Generally, it is 1-500 micrometers, 5-200 micrometers is preferable, and its 10-100 micrometers are especially preferable.

About the exposed surface of an adhesive layer or an adhesive bond layer, a separator is temporarily attached and covered for the purpose of the contamination prevention, etc., until it provides practically. Thereby, contact with an adhesive layer or an adhesive bond layer can be prevented in a usual handling state. As the separator, except for the above thickness conditions, for example, a plastic film, a rubber sheet, a paper, a cloth, a nonwoven fabric, a net, a foam sheet or a metal foil, and a laminate of a suitable type such as a laminate thereof may be silicone-based, long-chain alkyl-based or fluorine-based. And a conventional one such as those coated with an appropriate release agent such as molybdenum sulfide can be used.

In addition, in each layer, such as the said optical film, an adhesive layer, or an adhesive bond layer, ultraviolet absorbers, such as a salicylic acid ester compound, a benzophenol type compound, a benzotriazole type compound, a cyanoacrylate type compound, and a nickel complex salt type compound, are mentioned, for example. Ultraviolet absorption ability can be made by methods, such as the process of the process.

A polarizer is not specifically limited, Various things can be used. As a polarizer, dichroic substances, such as iodine and a dichroic dye, are made to adsorb | suck to hydrophilic polymer films, such as a polyvinyl alcohol-type film, a partially formalized polyvinyl alcohol-type film, and an ethylene-vinyl acetate copolymerization partial saponification film, for example. And polyene oriented films such as monoaxially stretched, dehydrated polyvinyl alcohol and dehydrochloric acid treated polyvinyl chloride. Among them, those obtained by stretching a polyvinyl alcohol-based film and adsorbing and aligning a dichroic material (iodine, dye) are preferably used. Although the thickness of a polarizer is not specifically limited, About 5-80 micrometers is common.

The polarizer which dyed a polyvinyl alcohol-type film with iodine, and uniaxially stretched can be produced by dyeing polyvinyl alcohol by immersing it in the aqueous solution of iodine, and extending | stretching 3 to 7 times the original length, for example. It can also be immersed in aqueous solution, such as a boric acid and potassium iodide, as needed. In addition, you may immerse a polyvinyl alcohol-type film in water and wash before dyeing as needed. In addition to washing the polyvinyl alcohol-based film with water, the contamination of the polyvinyl alcohol-based film and an antiblocking agent can be washed, and swelling of the polyvinyl alcohol-based film also has the effect of preventing irregularities such as staining. Stretching may be carried out after salting with iodine, or stretching while dyeing, or dyeing with iodine after stretching. It can extend | stretch also in aqueous solution, such as a boric acid and potassium iodide, or in a water bath.

The optical film (retardation film A side) is laminated on one side of the polarizer, but usually has a protective film on one side. It is preferable that a protective film is excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc. which are normally used as a protective film of a polarizer. As a material of the said protective film, For example, 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, and acryl Styrene-type polymers, such as a ronitrile styrene copolymer (AS resin), a polycarbonate polymer, etc. are mentioned. Further, polyolefin-based polymers, such as polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, ethylene-propylene copolymers, amide-based polymers such as vinyl chloride-based polymers, nylon and aromatic polyamides, imide-based polymers, and sulfides Phone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, An epoxy polymer, the blend of the said polymer, etc. are mentioned as an example of the polymer which forms a protective film. In addition, the thing which film-formed thermosetting type | mold ultraviolet-curable resins, such as an acryl type, urethane type, an acryl urethane type, an epoxy type, and a silicone type, etc. is mentioned.

Further, the polymer film described in Japanese Unexamined Patent Publication No. 2001-343529 (WO01 / 37007), for example, a thermoplastic resin having a substituted and / or unsubstituted imide group in the (A) side chain, and (B) a substituted and / or Or the resin composition containing the thermoplastic resin which has unsubstituted phenyl and a nitrile group is mentioned. As a specific example, the film of the resin composition containing the alternating copolymer which consists of isobutylene and N-methyl maleimide, and an acrylonitrile styrene copolymer is mentioned. As a film, the film which consists of a mixed extract of a resin composition, etc. can be used.

The protective film which can be used especially preferably from a point of polarization characteristic, durability, etc. is the triacetyl cellulose film which saponified the surface with alkali. Although the thickness of a protective film can be suitably determined, it is about 10-500 micrometers generally from the point of workability, thinness, etc., such as strength and handleability. 20-300 micrometers is especially preferable, and 30-200 micrometers is more preferable.

Moreover, it is preferable that a protective film does not have coloring as much as possible. Therefore, the film thickness direction represented by Rth = [(nx + ny) / 2-nz] · d (where nx and ny are the main refractive indexes in the film plane, nz is the refractive index in the film thickness direction and d is the film thickness). The protective film whose retardation value of -90 nm-+75 nm is used preferably. By using the thing whose phase difference value Rth of such a thickness direction is -90 nm-+75 nm, coloring (optical coloring) of the polarizing plate resulting from a protective film can be eliminated substantially. The thickness direction retardation value Rth is 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 via an aqueous adhesive. As an aqueous adhesive agent, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl latex type, an aqueous polyurethane, an aqueous polyester, etc. can be illustrated.

As said protective film, what hardened | cured the layer, the anti-reflective process, the sticking prevention, and the process which aimed at the diffusion or anti-glare can be used.

The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate, and the like, for example, a method of adding a cured film having excellent hardness, sliding properties, etc., by suitable ultraviolet curable resins such as acrylic or silicone, to the surface of the protective film. It can be formed as. The anti-reflection 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 anti-reflection film or the like according to the prior art. In addition, a sticking prevention process is performed in order to prevent adhesion with an adjacent layer.

Moreover, anti-crare process is performed in order to prevent that external light reflects on the surface of a polarizing plate, and to impede the visibility of the polarizing plate transmitted light, etc., for example, the roughening method by the sandblasting method or the embossing process system, It can form by giving a fine uneven structure to the surface of a protective film by a suitable method, such as a compounding method. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive inorganic substances made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 50 µm, for example. Transparent microparticles | fine-particles, such as organic microparticles | fine-particles which consist of microparticles | fine-particles, a crosslinked or uncrosslinked polymer, etc. are used. When forming surface fine uneven structure, the use amount of microparticles | fine-particles is about 2-50 weight part generally with respect to 100 weight part of transparent resin which forms surface fine uneven structure, and 5-25 weight part is preferable. The anti-glare layer may also serve as a diffusion layer (visual magnification function or the like) for diffusing the polarizing plate transmitted light to enlarge the time and the like.

The anti-reflection layer, the sticking prevention layer, the diffusion layer, the anti-glare layer, and the like may be formed on the protective film itself, and may be formed as a separate optical layer from the transparent protective layer.

The elliptical polarizing plate of the present invention is preferably used for a liquid crystal display device in IPS mode. A liquid crystal display device in the IPS mode includes a pair of substrates sandwiching a liquid crystal layer, an electrode group formed on one side of the pair of substrates, a liquid crystal composition material layer having dielectric anisotropy sandwiched between the substrates, And a liquid crystal cell formed opposite the pair of substrates and having an alignment control layer for arranging the 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. The electrode group has an arrangement structure arranged to apply a substantially parallel electric field to an interface between the alignment control layer and the liquid crystal composition material layer.

The elliptical 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. 3 is a case where the elliptically polarizing plate of FIG. 1 is disposed on the viewing side. As shown in FIG. 3, the elliptical polarizing plate has the optical film 2 side as the liquid crystal cell LC side. In FIG. 3, the polarizing plate 1 'is arrange | positioned at the reflection side (light incident side) of the liquid crystal cell 4 in which the elliptically polarizing plate is arrange | positioned. The absorption axis of the polarizing plate 1 'disposed on both sides of the substrate of the liquid crystal cell LC and the absorption axis of the elliptically polarizing plate (polarizing plate 1) are arranged in an orthogonal state. As the polarizing plate 1 ', what laminated | stacked the protective film 1b on both sides of the polarizer 1a is used normally.

The liquid crystal display of FIG. 3 shows an example of a liquid crystal cell.

EMBODIMENT OF THE INVENTION Although one Example of this invention is described below by giving an Example, it goes without saying that this invention is not limited to an Example.

In addition, the measurement of the refractive index and phase difference of each optical film is carried out by the automatic birefringence measuring apparatus (Oji Measurement Instruments Co., Ltd. make, automatic birefringence meter KOBRA2lADH) of (lambda) = 590 in the film plane and the thickness direction principal refractive index nx, ny, nz. The characteristic in nm was measured.

Reference Example

(Polarizer)

The polyvinyl alcohol film was immersed in hot water and expanded, and then dyed in an aqueous solution of iodine / calcium iodide, followed by uniaxial stretching in an aqueous solution of boric acid to obtain a polarizer. This polarizer was 43.5% transmittance and 99.9% polarization degree when the single transmittance, parallel transmittance, and orthogonal transmittance were examined with the spectrophotometer.

Example 1

(Phase difference film A)

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

(Retardation Film B)

5 parts by weight of the side chain type liquid crystal polymer represented by the formula (6, wherein the number represents mole% of the monomer unit and is conveniently represented by a block polymer unit), and a polymerizable liquid crystal showing a nematic liquid crystal phase (Paliocolor LC242, BASF) 20 parts by weight and a photoinitiator (Irgacure 907, manufactured by Chiba Specialty Chemicals Co., Ltd.) were prepared by dissolving 3 parts by weight of the polymerizable liquid crystal and 75 parts by weight of cyclohexanone. And the solution was apply | coated on the zeanoa film of Nippon Xeon company by the bar coater, and it was made to dry-orientate at 100 degreeC for 10 minutes, and then irradiated with ultraviolet-ray and hardened to obtain the homeotropic oriented liquid crystal film layer of thickness 1.0micrometer. As a result of measuring the optical phase difference of the sample (the incident light is perpendicular or inclined with respect to the sample surface), the homeotropic orientation is obtained in that the front phase difference is approximately zero and the phase difference increases with the increase in the incident angle of the measurement light. We confirmed that we were losing. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was -100 nm.

(Ellipse polarizer)

A transparent protective layer was formed by adhering a triacetyl cellulose (TAC) film having a thickness of 80 μm, a front phase difference of 6 nm, and a phase difference of 60 nm through a polyvinyl alcohol adhesive on one side of the polarizer obtained in the reference example. It was. On the other side of the polarizer, a polyvinyl alcohol-based adhesive was bonded to each other so that the absorption axis of the polarizer and the slow axis of the retardation film A were orthogonal to each other, and the retardation film B was attached thereon via an acrylic adhesive. Thereafter, the zeoa film was peeled off to obtain an elliptical polarizing plate.

Example 2

(Phase difference film A)

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

(Retardation Film B)

In Example 1, the homeotropic oriented liquid crystal film layer was obtained like Example 1 except having set the thickness of a homeotropic oriented liquid crystal film layer to 0.5 micrometer. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was -50 nm.

(Ellipse polarizer)

In Example 1, the elliptical polarizing plate was obtained like Example 1 except having used what was obtained above as retardation film A and retardation film B.

Example 3

(Phase difference film A)

A norbornene-based unstretched film (Aton film manufactured by JSR) having a thickness of 100 µm was uniaxially stretched at 1.35 times at 175 ° C. The obtained stretched film was thickness: 75 µm and front phase difference: 140 nm. The obtained stretched film had positive refractive index anisotropy (nx> ny ≒ nz).

(Retardation Film B)

In Example 1, the homeotropic oriented liquid crystal film layer was obtained like Example 1 except having set the thickness of the homeotropic oriented liquid crystal film layer to 1.3 micrometers. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was -130 nm.

(Ellipse polarizer)

In Example 1, the elliptical polarizing plate was obtained like Example 1 except having used what was obtained above as retardation film A and retardation film B.

Comparative Example 1

A transparent protective layer was formed by adhering a triacetyl cellulose (TAC) film having a thickness of 80 μm, a front phase difference of 6 nm, and a phase difference of 60 nm through a polyvinyl alcohol adhesive on one side of the polarizer obtained in the reference example. It was. A triacetyl cellulose (TAC) film having a thickness of 80 µm, a front phase difference of 6 nm, and a phase difference of 60 nm in the thickness direction was adhered to the other surface of the polarizer through a polyvinyl alcohol-based adhesive to obtain a polarizing plate.

Comparative Example 2

A transparent protective layer was formed by adhering a triacetyl cellulose (TAC) film having a thickness of 40 μm, a front retardation of 3 nm, and a retardation of 40 nm in thickness direction via a polyvinyl alcohol adhesive on one side of the polarizer obtained in the reference example. It was. The polarizing plate was obtained through the polyvinyl alcohol-type adhesive agent through the polyvinyl alcohol-type adhesive agent on the other surface of the polarizer through the polyvinyl alcohol-type adhesive agent through a polyvinyl alcohol-type adhesive agent whose thickness is 40 micrometers, front phase difference: 3 nm, phase direction of thickness direction: 40 nm. .

Comparative Example 3

(Retardation Film A ')

The polycarbonate film of 80 micrometers in thickness was uniaxially stretched 1.3 times at 175 degreeC. The obtained stretched film was thickness: 50 µm and front phase difference: 300 nm. The obtained stretched film had the refractive index anisotropy (nx> ny ≒ nz) of the quantity uniaxially oriented.

(Retardation Film B)

In Example 1, the homeotropic oriented liquid crystal film layer was obtained like Example 1 except having set the thickness of a homeotropic oriented liquid crystal film layer to 3.0 micrometers. The thickness direction retardation of the homeotropic alignment liquid crystal film layer was -300 nm.

(Ellipse polarizer)

In Example 1, the elliptical plate was obtained like Example 1 except having used what was obtained above as retardation film A 'obtained above instead of retardation film A, and retardation film B.

(evaluation)

The following evaluation was performed about the elliptical polarizing plate or polarizing plate obtained above. The results are shown in Table 1.

(Viewing angle)

As shown in FIG. 3, the elliptically polarizing plate obtained in Examples 1-3 was arrange | positioned at the visual recognition side of the liquid crystal cell of IPS mode. As shown in FIG. 4, the polarizing plates obtained by the comparative examples 1 and 2 were arrange | positioned at the visual recognition side of the liquid crystal cell of IPS mode. The elliptical polarizing plate obtained in Comparative Example 3 was used in place of the elliptic polarizing plate used in Example 1. On the other hand, the polarizing plate obtained by the comparative example 1 was arrange | positioned at the incident side (backlight side).

A white image and a black image are displayed on the liquid crystal display device, and in EZ contrast160D manufactured by ELDIM Co., Ltd., Y in the XYZ display system in the directions of 45 ° -225 ° diagonally and 135 ° -315 ° diagonally. The value, x value, and y value were measured. The angle at which the value of contrast (Y value (white image) / Y value (black image)) at that time became 25 or more was made into the viewing angle.

(Unevenness by adhesion stress)

The elliptically polarizing plate or polarizing plate (400 mm x 300 mm) obtained above was attached to alkali glass so that it might become cross nicol using an acrylic adhesive (20 micrometers) with a roller. The nonuniformity by the stress after adhesion was visually confirmed by the following reference | standard after irradiating a backlight.

(Circle): Light leakage was not recognized.

X: Light leakage was confirmed.

(Heating durability)

The elliptical polarizing plate or polarizing plate (300 mm × 200 mm) obtained above was pressed onto alkali glass with an acrylic pressure-sensitive adhesive (20 μm) using a roller to form cross nicol, followed by autoclave treatment at 50 ° C., 5 atmospheres, and 15 minutes. The bubble was removed, and the peripheral unevenness after 100 hours injecting under an environment of 80 ° C. was visually confirmed by the following criteria after irradiating the backlight.

(Circle): Light leakage was not recognized.

X: Light leakage was confirmed.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Viewing angle 70 70 65 40 40 30 Stress unevenness ○ ○ ○ ○ ○ × Heating durability ○ ○ ○ ○ ○ ×

The elliptical polarizing plate of the present invention can be preferably applied to image display devices such as liquid crystal display devices, organic EL (electroluminescence) display devices, and PDPs. In particular, the elliptical polarizing plate of the present invention is suitable for an active matrix liquid crystal display device of a transverse electric field system (IPS mode).

Claims (9)

It is composed of a thermoplastic polymer containing a cyclic polyolefin resin, the direction in which the in-plane refractive index is maximum is X axis, the direction perpendicular to the X axis is Y axis, the thickness direction is Z axis, and the refractive index in each axis direction is nx , ny, nz, the retardation film A which has positive refractive index anisotropy (nx> ny) nz) uniaxially oriented, and It is fixed in homeotropic orientation, the direction in which the refractive index in the plane becomes the maximum is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction is the Z axis, and the refractive indices of the respective axis directions are nx ₁ , ny ₁ , nz ₁ , the optical film obtained by laminating retardation film B having positive refractive index anisotropy (nz ₁ > nx ₁ ≒ ny ₁ ), It is an elliptical polarizing plate laminated | stacked so that the slow axis of retardation film A and the absorption axis of a polarizer may orthogonally cross on one side of a polarizer, In the elliptically polarizing plate, optical films are laminated so as to be in the order of retardation film A and retardation film B from the polarizer, The polarizer and the retardation film A are laminated by an adhesive layer, And the elliptical polarizing plate is used in a liquid crystal display device having a driving mode of a transverse electric field system (IPS mode) such that the optical film side is a liquid crystal cell side. delete The method of claim 1, Said retardation film A is a film containing norbornene-type resin, The elliptical polarizing plate characterized by the above-mentioned. The method of claim 1, The retardation film B is a retardation in the thickness direction: {((nx ₁ + ny ₁ ) / 2) -nz ₁ } × d (thickness: nm) is from -500 nm to -10 nm, wherein the elliptical polarizing plate is characterized in that it is. The method of claim 1, Retardation film B is a film containing a side chain type liquid crystal polymer, The elliptical polarizing plate characterized by the above-mentioned. The method of claim 1, Retardation film A is (lambda) / 4 plate, Elliptical polarizing plate characterized by the above-mentioned. delete The elliptical polarizing plate of any one of Claims 1 or 3 to 6 is laminated, The liquid crystal display device whose drive mode is a transverse electric field system (IPS mode). delete

Images