JP2007279411A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IPS (In-Plane Switching) mode liquid crystal display device which is improved in viewing angle with a simple configuration. <P>SOLUTION: The liquid crystal display device includes a first polarizing film (8), a first retardation layer (10), a second retardation layer (12), a third retardation layer (18), and a liquid crystal cell, in which a nematic liquid crystal material is held between a pair of substrates (13, 17). In the black display time, the nematic liquid crystal molecules are allined. The in-plane retardation Re of the first retardation layer (10) is 20-150nm; Nz defined with Nz=Rth/Re+0.5 is 1.5-7; in-plane refractive indexes nx and ny of the second retardation layer (12) are substantially equal to each other; nx<nz and retardation Rth in the thickness direction is -80 to -400 nm; in-plane refractive indexes nx and ny of the third retardation layer (18) are substantially identical to each other and nx<nz and retardation Rth in the thickness direction is -100 to 0 nm, and a transmission axis of the first polarizing film (8) is parallel to a slow axis direction of the liquid crystal molecules in the black display. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to an in-plane switching mode liquid crystal display device that performs display by applying a horizontal electric field to liquid crystal molecules aligned in a horizontal direction.

  As a liquid crystal display device, a so-called TN mode is widely used in which a liquid crystal layer in which nematic liquid crystal is twisted is sandwiched between two orthogonal polarizing plates and an electric field is applied in a direction perpendicular to the substrate. In this system, since the liquid crystal rises with respect to the substrate during black display, birefringence occurs due to liquid crystal molecules when viewed from an oblique direction, and light leakage occurs. To solve this problem, a system for optically compensating the liquid crystal cell and preventing this light leakage by using a film in which liquid crystal molecules are hybrid-aligned has been put into practical use. However, even if liquid crystal molecules are used, it is very difficult to completely optically compensate the liquid crystal cell without any problem, resulting in a problem that gradation reversal in the lower direction of the screen cannot be suppressed.

  In order to solve such a problem, a liquid crystal display device using a so-called in-plane switching (IPS) mode in which a lateral electric field is applied to the liquid crystal, or a liquid crystal having a negative dielectric anisotropy is vertically aligned in the panel. A vertical alignment (VA) mode in which alignment is divided by protrusions and slit electrodes has been proposed and put into practical use. In recent years, these panels have been developed not only for monitor applications but also for TV applications, and as a result, screen brightness has been greatly improved. On the other hand, a slight light leakage in the diagonally oblique incidence direction during black display, which has not been considered as a problem in these operation modes, has become apparent as a cause of a decrease in display quality.

  As one means for improving the color tone and the viewing angle of black display, the arrangement of an optical compensation material having birefringence characteristics between the liquid crystal layer and the polarizing plate is also studied in the IPS mode. For example, by arranging a birefringent medium having an optical axis orthogonal to each other to compensate for the increase / decrease in retardation of the liquid crystal layer during tilting, a white display or a halftone display is diagonally arranged between the substrate and the polarizing plate. It is disclosed that coloring can be improved when viewing directly from (see Patent Document 1). In addition, a method using an optical compensation film made of a styrenic polymer having a negative intrinsic birefringence or a discotic liquid crystalline compound (see Patent Documents 2, 3, and 4), or an optical axis as an optical compensation film with positive birefringence. Is a method of combining a film in the plane of the film with a film having a positive birefringence and an optical axis in the normal direction of the film (see Patent Document 5), biaxial optical compensation with a retardation of 1/2 wavelength A method using a sheet (see Patent Document 6), a method using a film having a negative retardation as a protective film of a polarizing plate, and providing an optical compensation layer having a positive retardation on this surface (see Patent Document 7) Proposed. In addition, an IPS mode liquid crystal display device having first and second retardation regions having predetermined optical characteristics has been proposed, and as a preferable aspect thereof, a liquid crystal display device in which the polarizing plate protective film has predetermined optical characteristics is proposed. It has been proposed (Patent Document 8).

Japanese Patent Laid-Open No. 9-80424 Japanese Patent Laid-Open No. 10-54982 JP-A-11-202323 Japanese Patent Laid-Open No. 9-292522 JP 11-133408 A JP-A-11-305217 JP-A-10-307291 JP 2005-265889 A

However, many of the proposed methods are methods that improve the viewing angle by canceling the birefringence anisotropy of the liquid crystal in the liquid crystal cell, so the polarization axis crossing angle when the orthogonal polarizing plate is viewed from an oblique direction. There is a problem that the light leakage based on the deviation from orthogonality cannot be solved sufficiently. In addition, even in a system that can compensate for this light leakage, it is very difficult to completely optically compensate the liquid crystal cell. Furthermore, in the optical compensation sheet for IPS mode liquid crystal cell that performs optical compensation with the stretched birefringent polymer film, it is necessary to use a plurality of films. As a result, the thickness of the optical compensation sheet increases, and the display device becomes thinner. It is disadvantageous. Moreover, since an adhesive layer is used for lamination | stacking of a stretched film, the adhesive layer contracted by the temperature / humidity change, and defects, such as peeling and a curvature between films, may generate | occur | produce.
Further, the liquid crystal display device of Patent Document 8 shows a CR map that is small in color tone and is substantially line-symmetric with respect to the slow axis direction during black display of the liquid crystal cell. However, for example, when the slow axis direction of the liquid crystal cell is up and down with respect to the screen, the color changes to red when observed from the upper right and blue when observed from the lower right, and the difference is noticeable.

  The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an IPS liquid crystal display device that has a simple configuration and that reduces not only the display quality but also the color change depending on the viewing angle. To do.

Means for solving the above-mentioned problems are as follows.
[1] At least a first polarizing film, a first retardation layer, a second retardation layer, a third retardation layer, and a liquid crystal cell in which a liquid crystal layer made of a nematic liquid crystal material is sandwiched between a pair of substrates. A liquid crystal display device in which liquid crystal molecules of the nematic liquid crystal material are aligned parallel to the surfaces of the pair of substrates during black display,
The in-plane retardation Re of the first retardation layer is 20 nm to 150 nm, and the value Nz defined by Nz = Rth / Re + 0.5 is 1.5 to 7,
The in-plane refractive indexes nx and ny of the second retardation layer are substantially equal, nx <nz, and the retardation Rth in the thickness direction is −80 nm to −400 nm,
The in-plane refractive indexes nx and ny of the third retardation layer are substantially equal, nx <nz, the retardation Rth in the thickness direction is −100 nm to 0 nm, and the transmission axis of the first polarizing film is A liquid crystal display device parallel to the slow axis direction of liquid crystal molecules during black display.
[2] The first polarizing film, the first retardation layer, the second retardation layer, the liquid crystal cell, and the third retardation layer are arranged in this order, and the first retardation layer is delayed. The liquid crystal display device according to [1], wherein a phase axis is substantially parallel to a transmission axis of the first polarizing film.
[3] A second polarizing film having a transmission axis perpendicular to the transmission axis of the first polarizing film is further included, and the first and second polarizing films are the first retardation layer and the second retardation layer. And the liquid crystal display device according to [1] or [2], wherein the liquid crystal cell is interposed therebetween.
[4] A pair of protective films disposed with the first polarizing film and / or the second polarizing film interposed therebetween, and the thickness direction retardation of the protective film on the side close to the liquid crystal layer of the pair of protective films. The liquid crystal display device according to any one of [1] to [3], wherein Rth is 40 nm or less.
[5] The first polarizing film and / or the second polarizing film has a protective film on the surface opposite to the liquid crystal layer, and the first retardation layer and the second polarizing film are formed on the surface close to the liquid crystal layer. Any one of the retardation layer and the third retardation layer is in contact with the liquid crystal display device according to any one of [1] to [3].
[6] A pair of protective films disposed between the first polarizing film and / or the second polarizing film, wherein the protective film on the side close to the liquid crystal layer of the pair of protective films is a cellulose acylate film or The liquid crystal display device according to any one of [1] to [3], which is a norbornene film.
[7] The liquid crystal display device according to any one of [1] to [6], wherein the second retardation layer has a retardation layer containing a rod-like liquid crystal compound that is substantially vertically aligned.

  Including at least a first polarizing film, a first retardation layer, a second retardation layer, a third retardation layer, and a liquid crystal cell in which a liquid crystal layer made of a nematic liquid crystal material is sandwiched between a pair of substrates, A liquid crystal display device in which liquid crystal molecules of the nematic liquid crystal material are aligned in parallel to the surfaces of the pair of substrates at the time of display, the in-plane retardation Re of the first retardation layer is 20 nm to 150 nm, and Nz = The value Nz of the first retardation layer defined by Rth / Re + 0.5 is 1.5 to 7, the in-plane refractive indexes nx and ny are substantially equal, and nx <nz. The retardation Rth in the thickness direction of the second retardation layer is −80 nm to −400 nm, the in-plane refractive indexes nx and ny are substantially equal, nx <nz, Retardation Rth in thickness direction of three retardation layers By making the transmission axis of the first polarizing film parallel to the slow axis direction of the liquid crystal molecules at the time of black display, the azimuth angle direction is oblique without changing any characteristics in the front direction. When viewed from above, it is possible to improve the contrast reduction caused by the deviation of the absorption axes of the two polarizing plates from 90 degrees, particularly the contrast reduction from the oblique direction of 45 degrees. Furthermore, it is possible to provide a liquid crystal display device in which the color change depending on the viewing direction is reduced.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, an embodiment of the liquid crystal display device of the present invention and its constituent members will be described in order. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  In the present specification, “parallel” and “orthogonal” mean that the angle is within a range of strictly less than ± 10 °. In this range, an error from a strict angle is preferably less than ± 5 °, and more preferably less than ± 2 °. Further, “substantially vertical” means within a range of less than ± 20 ° from a strict vertical angle. In this range, an error from a strict angle is preferably less than ± 15 °, and more preferably less than ± 10 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.

  In this specification, “polarizing plate” is cut into a size to be incorporated into a long polarizing plate and a liquid crystal device unless otherwise specified (in this specification, “cutting” includes “punching” and “cutting out”. It is used in the meaning including both of the polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other. “Polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. It shall be. In this specification, the “retardation layer” is used not only for a single layer structure but also for a stacked structure in which a plurality of layers are stacked.

In the present specification, Re (λ) and Rth (λ) respectively represent in-plane retardation and retardation in the thickness direction at a wavelength λ. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (when there is no slow axis, Rth (λ) With respect to the film normal direction (with an arbitrary direction as the rotation axis), the light of wavelength λ nm is incident from each inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side, and a total of 6 points are measured. KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.

  In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (1) and (2).

式（２） Ｒｔｈ＝（（ｎｘ＋ｎｙ）／２−ｎｚ） × ｄ

注記： 式中、Ｒｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値を表す。
式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表す。

Formula (2) Rth = ((nx + ny) / 2−nz) × d

Note: In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction.
In the formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotation axis), and −50 degrees to +50 degrees with respect to the film normal direction 11 points of light having a wavelength of λ nm are incident from the inclined direction in 10 degree steps until KOBRA 21ADH is measured based on the measured retardation value, the assumed average refractive index, and the input film thickness value. Or WR calculates.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
By inputting these assumed values of average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 3 are schematic views of an embodiment of the liquid crystal display device of the present invention. FIG. 2 is a schematic diagram showing an example of a pixel region of the liquid crystal display device of the present invention.
[Liquid Crystal Display]
The liquid crystal display device shown in FIG. 1 includes polarizing films 8 and 20, a first retardation layer 10, a second retardation layer 12, a third retardation layer 18, substrates 13 and 17, and sandwiched between the substrates. The liquid crystal layer 15 is provided. The polarizing films 8 and 20 are sandwiched between protective films 7a and 7b and 19a and 19b, respectively.

  In the liquid crystal display device of FIG. 1, the liquid crystal cell includes substrates 13 and 17 and a liquid crystal layer 15 sandwiched between them. The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is optimal in the range of 0.2 to 0.4 μm for the IPS type having no twisted structure in the transmission mode. In this range, the white display luminance is high and the black display luminance is small, so that a bright and high-contrast display device can be obtained. An alignment film (not shown) is formed on the surfaces of the substrates 13 and 17 that are in contact with the liquid crystal layer 15 to align liquid crystal molecules substantially parallel to the surface of the substrate and to be rubbed on the alignment film. The processing direction 14 controls the alignment direction of the liquid crystal molecules when no voltage is applied or when the voltage is not applied. Further, an electrode (not shown in FIG. 1) capable of applying a voltage to the liquid crystal molecules is formed on the inner surface of the substrate 13 or 17.

  FIG. 2 schematically shows the orientation of the liquid crystal molecules in one pixel region of the liquid crystal layer 15. FIG. 2 shows the alignment of the liquid crystal molecules in a very small area corresponding to one pixel of the liquid crystal layer 15 in the rubbing direction 4 of the alignment film formed on the inner surfaces of the substrates 13 and 17 and the substrates 13 and 17. It is the schematic diagram shown with the electrodes 2 and 3 which can apply a voltage to the liquid crystal molecule formed in the inner surface. When active driving is performed using a nematic liquid crystal having positive dielectric anisotropy as a field effect liquid crystal, the liquid crystal molecule alignment directions in a no voltage application state or a low application state are 5a and 5b. A display is obtained. When applied between the electrodes 2 and 3, the liquid crystal molecules change their alignment direction in the directions of 6 a and 6 b in accordance with the voltage. Usually, bright display is performed in this state.

  In FIG. 1 again, the absorption axis 9 of the polarizing film 8 and the absorption axis 21 of the polarizing film 20 are arranged orthogonally. The slow axis 11 of the first retardation layer 10 is orthogonal to the absorption axis 9 of the polarizing film 8 and parallel to the slow axis direction 16 of the liquid crystal molecules in the liquid crystal layer 15 during black display. That is, the transmission axis of the polarizing film 9 (the axis perpendicular to the absorption axis 9) is parallel to the slow axis direction 16 of the liquid crystal molecules in the liquid crystal layer 15 during black display. In the liquid crystal display device shown in FIG. 1, the polarizing film 8 is sandwiched between two protective films 7a and 7b, and the polarizing film 20 is also sandwiched between two protective films 19a and 19b.

The first retardation layer 10 having predetermined optical characteristics and the second retardation layer having predetermined optical characteristics are disposed between the liquid crystal layer 15 and the polarizing film 8 with respect to the position of the liquid crystal layer 15, The third retardation layer having predetermined optical characteristics is disposed between the liquid crystal layer 15 and the polarizing film 20. Either of the polarizing films 8 and 20 may be the viewing side or the back side. However, in any aspect, the arrangement relationship between the first retardation layer 10 and the second retardation layer 12 is arranged such that the second retardation layer 12 is closer to the liquid crystal layer 15.
Details of the first retardation layer, the second retardation layer, and the third retardation layer will be described later.

  Another embodiment of the present invention is shown in FIG. The liquid crystal display device of FIG. 3 has a first retardation layer 10 instead of the protective film 7b of the polarizing film 8 in FIG. 1 and a third retardation layer 18 instead of the protective film 19a of the polarizing film 20. Also plays a role. In other configurations, for example, the arrangement relationship between the slow axis during black display of the liquid crystal layer 15 and the absorption axis 9 of the polarizing film 8 is the same as in FIG. Also in the embodiment of FIG. 3, the polarizing films 8 and 20 may be either on the viewing side or on the back side. However, in any aspect, the arrangement relationship between the first retardation layer 10 and the second retardation layer 12 is arranged such that the second retardation layer 12 is closer to the liquid crystal layer 15.

  1 and 3 show a mode of a transmissive mode display device including an upper polarizing plate and a lower polarizing plate, the present invention is a mode of a reflective mode including only one polarizing plate. In such a case, since the optical path in the liquid crystal cell is doubled, the optimum value of Δn · d is about the above half value.

  The liquid crystal display device of the present invention is not limited to the configuration shown in FIGS. 1 to 3 and may include other members. For example, a color filter may be disposed between the liquid crystal layer and the polarizing film. Further, an antireflection treatment or a hard coat may be applied to the surface of the protective film of the polarizing film. Moreover, you may use what gave electroconductivity to the structural member. In the case of use as a transmission type, a cold cathode or a hot cathode fluorescent tube, or a backlight having a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed on the back surface. In this case, the arrangement of the backlight may be on the upper side or the lower side in FIGS. In addition, a reflective polarizing plate, a diffusion plate, a prism sheet, or a light guide plate can be disposed between the liquid crystal layer and the backlight. In addition, as described above, the liquid crystal display device of the present invention may be of a reflective type. In such a case, only one polarizing plate may be disposed on the observation side, and the back side of the liquid crystal cell or the lower side of the liquid crystal cell. A reflective film is disposed on the inner surface of the substrate. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side.

  The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective when applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as TFT or MIM. Of course, a mode applied to a passive matrix liquid crystal display device called time-division driving is also effective.

  Hereinafter, preferred optical characteristics of various members usable in the liquid crystal display device of the present invention, materials used for the members, manufacturing methods thereof, and the like will be described in detail.

[First retardation layer]
The first retardation layer included in the present invention has an in-plane retardation Re of 20 nm to 150 nm, and in order to effectively reduce light leakage in an oblique direction, the Re of the first retardation layer is 40 nm. It is more preferably ˜115 nm, and further preferably 60 nm to 95 nm. Further, Nz defined by Nz = Rth / Re + 0.5 is 1.5 to 7, and in order to effectively reduce light leakage in an oblique direction, Nz of the first retardation layer is 2. It is more preferably 0 to 5.5, and further preferably 2.5 to 4.5.

  Basically, the material and form of the first retardation layer are not particularly limited as long as it has the optical characteristics. For example, a retardation film made of a birefringent polymer film, a film obtained by applying a high molecular compound on a transparent support and then heated and salted, and a low molecular weight or high molecular liquid crystalline compound applied or transferred onto the transparent support Any of the retardation films having the retardation layer formed can be used. Moreover, the laminated body which laminated | stacked each can also be used as a 1st phase difference layer.

  The birefringent polymer film is preferably a film having excellent controllability of birefringence characteristics, transparency and heat resistance. In this case, the polymer material to be used is not particularly limited as long as it is a polymer capable of achieving uniform biaxial orientation, but is preferably a conventionally known material that can be formed by a solution casting method or an extrusion method, and is preferably a norbornene-based material. Polymers, polycarbonate polymers, polyarylate polymers, polyester polymers, aromatic polymers such as polysulfone, cellulose acylate, or polymers in which two or more of these polymers are mixed It is done.

The biaxial orientation of the film is a film made of the thermoplastic resin produced by an appropriate method such as an extrusion molding method or a casting film forming method, for example, a longitudinal stretching method using a roll, a transverse stretching method using a tenter, or a biaxial stretching method. For example, it can be achieved by performing a stretching treatment. In the longitudinal stretching method using the roll, an appropriate heating method such as a method using a heating roll, a method of heating an atmosphere, or a method of using them together can be employed. In the biaxial stretching method using a tenter, an appropriate method such as a simultaneous biaxial stretching method using an all tenter method or a sequential biaxial stretching method using a roll tenter method can be employed.
Moreover, a thing with little orientation nonuniformity and phase difference nonuniformity is preferable. Although the thickness can be appropriately determined depending on the phase difference or the like, generally 1 to 300 μm is preferable, 10 to 200 μm is more preferable, and 20 to 150 μm is more preferable from the viewpoint of thinning.

  As the norbornene-based polymer, norbornene and its derivatives, tetracyclododecene and its derivatives, dicyclopentadiene and its derivatives, methanotetrahydrofluorene and its monomers as a main component of a monomer polymer, Ring-opening polymer of norbornene monomer, ring-opening copolymer of norbornene monomer and other monomer capable of ring-opening copolymerization, addition polymer of norbornene monomer, copolymerizable with norbornene monomer Examples include addition copolymers with other monomers and hydrogenated products thereof. Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a ring-opening polymer hydride of a norbornene monomer is most preferable. The molecular weight of the norbornene-based polymer, the polymer of the monocyclic olefin or the polymer of the cyclic conjugated diene is appropriately selected according to the purpose of use, but the cyclohexane solution (toluene solution if the polymer resin does not dissolve) The polyisoprene or polystyrene-converted weight average molecular weight measured by gel permeation chromatography is usually 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000. When the thickness is in the range, the mechanical strength of the film (A) and the moldability are highly balanced, which is preferable.

  The acyl group of cellulose acylate may be an aliphatic group or an allyl group, and is not particularly limited. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, aromatic alkyl carbonyl esters, etc. of cellulose, each of which may further have a substituted group, and an ester having a total carbon number of 22 or less. Groups are preferred. These preferred cellulose acylates include acyl groups having a total carbon number of 22 or less in the ester moiety (for example, acetyl, propionyl, butyroyl, barrel, heptanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, hexadecanoyl, octadecanoyl, etc. ), Arylcarbonyl groups (such as acrylic and methacrylic), allylcarbonyloxy (such as benzoyl and naphthaloyl), and cinnamoyl groups. Among these, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate stearate, cellulose acetate benzoate, etc. are not particularly limited in the case of mixed esters, but preferably acetate is the total ester. It is preferable that it is 30 mol% or more.

  Among these, cellulose acylate is preferred, and photographic grades are particularly preferred, and commercially available photographic grades can be obtained with satisfactory quality such as viscosity average degree of polymerization and substitution degree. As manufacturers of photographic grade cellulose triacetate, Daicel Chemical Industries, Ltd. (for example, LT-20, 30, 40, 50, 70, 35, 55, 105, etc.), Eastman Kodak Company (for example, CAB-551) 0.01, CAB-551-0.02, CAB-500-5, CAB-381-0.5, CAB-381-02, CAB-381-20, CAB-321-0.2, CAP-504 0.2, CAP-482-20, CA-398-3, etc.), Coatles, Hoechst, etc., any of which can use photographic grade cellulose acylate. Further, for the purpose of controlling the mechanical properties and optical properties of the film, plasticizers, surfactants, retardation modifiers, UV absorbers, and the like can be used in the future (reference material: JP-A No. 2002-277632). Publication, Unexamined-Japanese-Patent No. 2002-182215).

As a method for forming the transparent resin into a sheet or film, for example, either a hot melt molding method or a solution casting method can be used. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, a stretch molding method, etc. Among these methods, mechanical strength, surface In order to obtain a film excellent in accuracy and the like, the extrusion molding method, the inflation molding method, and the press molding method are preferable, and the extrusion molding method is most preferable. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the heat-melt molding method, the cylinder temperature is preferably set in the range of preferably 100 to 400 ° C, more preferably 150 to 350 ° C. The thickness of the sheet or film is preferably 10 to 300 μm, more preferably 30 to 200 μm.
When the glass transition temperature of the transparent resin is Tg, the stretching of the sheet or film is preferably in a temperature range of Tg-30 ° C to Tg + 60 ° C, more preferably in a temperature range of Tg-10 ° C to Tg + 50 ° C. In at least one direction, the stretching ratio is preferably 1.01 to 2 times. The stretching direction may be at least one direction, but when the sheet is obtained by extrusion, the direction is preferably the mechanical flow direction (extrusion direction) of the resin. A free shrink uniaxial stretching method, a fixed width uniaxial stretching method, a biaxial stretching method, and the like are preferable. The optical characteristics can be controlled by controlling the draw ratio and the heating temperature.

[Second retardation layer]
The in-plane refractive indexes nx and ny of the second retardation layer included in the liquid crystal display device of the present invention are substantially equal, and the refractive index nz in the thickness direction satisfies nx <ny. The retardation Rth in the thickness direction of the second retardation layer is −80 nm to −400 nm. A more preferable range of Rth of the second retardation layer varies depending on the optical characteristics of other optical members in the liquid crystal display device, and in particular, a protective film (for example, triacetylcellulose) of a polarizing film located closer to the second retardation layer. It varies greatly depending on the Rth of the film. In order to effectively reduce the light leakage in the oblique direction, Rth of the second retardation layer is preferably −100 nm to −340 nm, and more preferably −120 nm to −270 nm. On the other hand, nx and ny of the second retardation layer are substantially the same as described above, and Re has a value near 0. Specifically, the in-plane retardation Re is preferably 0 to 50 nm, and more preferably 0 to 20 nm.

  The material and form of the second retardation layer are not particularly limited as long as it has the optical characteristics. For example, a retardation film made of a birefringent polymer film and a retardation film having a retardation layer formed by applying or transferring a low molecular weight or high molecular liquid crystalline compound onto a transparent support are used. be able to. Moreover, each can also be laminated | stacked and used.

  The retardation film made of a birefringent polymer film having the above optical characteristics is obtained by stretching a polymer film in the thickness direction of the film, or applying and drying a vinylcarbazole polymer (Japanese Patent Laid-Open No. 2001-091746). Publication). In addition, as a retardation layer formed from a liquid crystalline compound having the above optical characteristics, a cholesteric discotic liquid crystal compound or composition containing a chiral structural unit is fixed after its helical axis is aligned substantially perpendicular to the substrate. Examples thereof include a layer formed by forming a rod-like liquid crystal compound or composition having a positive refractive index anisotropy and a composition formed by orienting the substrate substantially perpendicularly to the substrate and then immobilizing it (for example, JP-A-6-6 331826 and Japanese Patent No. 2853064). The rod-like liquid crystal compound may be a low molecular compound or a high molecular compound. Furthermore, not only one retardation layer but also a plurality of retardation layers can be laminated to form a second retardation layer exhibiting the above optical characteristics. Further, the second retardation layer may be configured so that the entire laminated body of the support and the retardation layer satisfies the optical characteristics. As the rod-like liquid crystal compound to be used, those that take a nematic liquid crystal phase, a smectic liquid crystal phase, and a lyotropic liquid crystal phase in a temperature range in which the orientation is fixed are preferably used. A liquid crystal exhibiting a smectic A phase and a B phase capable of obtaining uniform vertical alignment without fluctuation is preferable. In particular, in the presence of an additive, a rod-like liquid crystalline compound that becomes a liquid crystal state in an appropriate orientation temperature range is formed by using a composition containing the additive and the rod-like liquid crystalline compound. Is also preferable.

《Bar-shaped liquid crystalline compound》
In the present invention, the second retardation layer may be formed from a composition containing a rod-like liquid crystalline compound. Examples of the rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used. As the liquid crystal molecules, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are preferably used. The number of the partial structures is 1 to 6, preferably 1 to 3.

  When the second retardation layer includes a retardation layer formed by fixing the rod-like liquid crystalline compound in the aligned state, the rod-like liquid crystalline compound is substantially vertically aligned and fixed in that state. It is preferable to use a retardation layer. The term “substantially perpendicular” means that the angle formed between the film surface and the director of the rod-like liquid crystal compound is in the range of 70 ° to 90 °. These liquid crystalline compounds may be aligned obliquely or may be changed so that the inclination angle gradually changes (hybrid alignment). Even in the case of oblique orientation or hybrid orientation, the average inclination angle is preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and most preferably 85 ° to 90 °.

  A retardation layer formed from a composition containing a rod-like liquid crystalline compound supports a coating liquid containing a rod-like liquid crystalline compound, and optionally, the following polymerizable initiator, air interface vertical alignment agent and other additives. It can be formed by applying on the vertical alignment film formed on the body, vertically aligning, and fixing the alignment state. When it is formed on a temporary support, it can also be produced by transferring the retardation layer onto the support. Furthermore, not only one retardation layer but also a plurality of retardation layers may be laminated to form a second retardation layer exhibiting the above optical characteristics. Moreover, you may utilize as a 2nd phase difference layer by satisfy | filling the said optical characteristic with the whole laminated body of a support body and a phase difference layer.

  As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  The vertically aligned liquid crystal compound is preferably fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (described in U.S. Pat. No. 4,221,970).

It is preferable that the usage-amount of a photoinitiator is 0.01-20 mass% of solid content of a coating liquid, and it is more preferable that it is 0.5-5 mass%. The light irradiation for polymerizing the rod-like liquid crystalline molecules preferably uses ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the first retardation layer including the optically illegal layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

<< Vertical alignment film >>
In order to align the liquid crystalline compound vertically on the alignment film side, it is important to reduce the surface energy of the alignment film. Specifically, the surface energy of the alignment film is lowered by the functional group of the polymer, thereby bringing the molecules of the liquid crystal compound into an upright state. As the functional group for reducing the surface energy of the alignment film, a hydrocarbon group having 10 or more fluorine atoms and carbon atoms is effective. In order to allow a fluorine atom or a hydrocarbon group to exist on the surface of the alignment film, it is preferable to introduce a fluorine atom or a hydrocarbon group into the side chain rather than the main chain of the polymer. The fluoropolymer preferably contains fluorine atoms in a proportion of 0.05 to 80% by mass, more preferably in a proportion of 0.1 to 70% by mass, and in a proportion of 0.5 to 65% by mass. More preferably, it is most preferable to contain in the ratio of 1-60 mass%. The hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched or linear. The aliphatic group is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The hydrocarbon group may have a substituent that does not exhibit strong hydrophilicity, such as a halogen atom. The hydrocarbon group has preferably 10 to 100 carbon atoms, more preferably 10 to 60, and most preferably 10 to 40 carbon atoms. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

  Polyimide is generally synthesized by a condensation reaction of tetracarboxylic acid and diamine. A polyimide corresponding to a copolymer may be synthesized using two or more kinds of tetracarboxylic acids or two or more kinds of diamines. The fluorine atom or hydrocarbon group may be present in the repeating unit derived from tetracarboxylic acid, may be present in the repeating unit derived from diamine, or may be present in both repeating units. When introducing a hydrocarbon group into polyimide, it is particularly preferable to form a steroid structure in the main chain or side chain of the polyimide. The steroid structure present in the side chain corresponds to a hydrocarbon group having 10 or more carbon atoms, and has a function of vertically aligning the liquid crystalline compound. In this specification, the steroid structure is a cyclopentanohydrophenanthrene ring structure or a ring structure in which a part of the ring bond is a double bond in the range of an aliphatic ring (a range that does not form an aromatic ring). means.

  Further, as a means for vertically aligning the liquid crystalline compound, a method of mixing an organic acid with a polymer of polyvinyl alcohol, modified polyvinyl alcohol, or polyimide can be suitably used. As the acid to be mixed, carboxylic acid, sulfonic acid and amino acid are preferably used. You may use what shows the acidity among the below-mentioned air interface aligning agent. Moreover, quaternary ammonium salts can also be used suitably. The mixing amount is preferably 0.1% by mass to 20% by mass and more preferably 0.5% by mass to 10% by mass with respect to the polymer.

  The saponification degree of the polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.

  The alignment film used for aligning the molecules of the rod-like liquid crystalline compound is preferably made of a polymer having a hydrophobic group as a functional group in the side chain. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. Specific examples of these modified polyvinyl alcohol compounds include, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426. And the like described in [0022].

  The alignment film is formed by using a polymer having a side chain having a crosslinkable functional group bonded to the main chain or a polymer having a crosslinkable functional group on a side chain having a function of aligning liquid crystal molecules. When the retardation film is formed using a composition containing a polyfunctional monomer, the polymer in the alignment film and the polyfunctional monomer in the retardation film formed thereon can be copolymerized. As a result, a covalent bond is formed not only between the polyfunctional monomers but also between the alignment film polymers and between the polyfunctional monomer and the alignment film polymer, and the alignment film and the retardation film are firmly bonded. Therefore, the strength of the optical compensation sheet can be remarkably improved by forming the alignment film using a polymer having a crosslinkable functional group. The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [024] in JP-A No. 2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without occurrence of reticulation can be obtained.

  The alignment film can be basically formed by applying a composition containing the polymer and the crosslinking agent, which are alignment film forming materials, onto a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. it can. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the alignment film and also the phase difference layer surface reduces remarkably.

  The coating method used when forming the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film may be provided on the support. The alignment film is used by crosslinking the polymer layer as described above. The rubbing treatment is preferably not performed for the vertical alignment of the rod-like liquid crystalline compound. In addition, after aligning a liquid crystalline compound using an alignment film, the liquid crystalline compound is fixed in the aligned state to form a retardation layer, and only the retardation layer is formed on the polymer film (or transparent support). You may transcribe.

《Air interface vertical alignment agent》
Usually, since the liquid crystalline compound has a property of being inclined and aligned on the air interface side, it is necessary to control the alignment of the liquid crystalline compound vertically on the air interface side in order to obtain a uniformly vertically aligned state. . For this purpose, a phase difference film is formed by adding a compound that is unevenly distributed on the air interface side and that has the effect of vertically aligning the liquid crystalline compound by its excluded volume effect or electrostatic effect to the liquid crystal coating liquid. It is preferable to do this.

  As the air interface alignment agent, compounds described in JP-A Nos. 2002-20363 and 2002-129162 can be used. Also, paragraph numbers [0072] to [0075] of Japanese Patent Application No. 2002-212100, paragraph numbers [0037] to [0039] of Japanese Patent Application No. 2002-262239, and paragraphs of Japanese Patent Application No. 2003-91752. Nos. [0071] to [0078], paragraph numbers [0052] to [0054], [0065] to [0066], [0092] to [0094] of Japanese Patent Application No. 2003-119959, Japanese Patent Application No. 2003-330303 The matters described in paragraph numbers [0028] to [0030] of the specification and paragraph numbers [0087] to [0090] of Japanese Patent Application No. 2004-003804 can also be appropriately applied to the present invention. Moreover, by mix | blending these compounds, applicability | paintability is improved and generation | occurrence | production of a nonuniformity or a repellency is suppressed.

  The amount of the air interface alignment agent used in the liquid crystal coating liquid is preferably 0.05% by mass to 5% by mass. Moreover, when using a fluorine-type air interface aligning agent, it is preferable that it is 1 mass% or less.

<Other materials in retardation layer>
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specifically, for example, compounds described in JP-A-2001-330725, paragraphs [0028] to [0056], and paragraphs [0069] to [0126] described in Japanese Patent Application No. 2003-295212. The compound of this is mentioned.

  The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.

[Support]
In the present invention, a retardation layer formed from a liquid crystal compound may be formed on a support. The support is preferably transparent, and specifically, the light transmittance is preferably 80% or more. The support preferably has a small wavelength dispersion. Specifically, the Re400 / Re700 ratio is preferably less than 1.2. Among these, a polymer film is preferable. The transparent support can also serve as the first retardation layer, the second retardation layer, or the polarizing plate protective film. The transparent support and the whole retardation layer may constitute the first retardation layer or the second retardation layer. The optical anisotropy of the support is preferably small, and the in-plane retardation (Re) is preferably 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less. Moreover, when it serves also as a 1st phase difference layer, retardation Re is 20 nm-150 nm, It is more preferable that it is 40 nm-115 nm, It is more preferable that it is 60 nm-95 nm. Moreover, Nz is 1.5-7, it is more preferable that it is 2.0-5.5, and it is further more preferable that it is 2.5-4.5.

  Examples of the polymer film as the support include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate films. A cellulose ester film is preferred, an acetyl cellulose film is more preferred, and a triacetyl cellulose film is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 40 to 200 μm. In order to improve adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or retardation layer) provided thereon, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light (UV) ) Treatment, flame treatment). An adhesive layer (undercoat layer) may be provided on the transparent support. Moreover, the average particle diameter is 10 to 100 nm in order to provide the transparent support or the long transparent support with slipperiness in the conveying process or to prevent the back surface and the surface from sticking after winding. It is preferable to use what formed the polymer layer which mixed the inorganic particle of about 5%-40% by solid content weight ratio by the application | coating or co-casting with the support body on the one side of the support body.

[Protective film for polarizing film]
As the first and second protective films for the polarizing film, those having no absorption in the visible light region, a light transmittance of 80% or more, and a retardation based on birefringence are preferable. Specifically, the in-plane Re is preferably 0 to 30 nm, more preferably 0 to 15 nm, and most preferably 0 to 5 nm. Further, the retardation Rth in the thickness direction is preferably 0 to 40 nm, more preferably 0 to 20 nm, and most preferably 0 to 10 nm. Any film having this property can be preferably used, but from the viewpoint of durability of the polarizing film, a cellulose acylate or norbornene film is more preferable. Examples of a method for reducing Rth of the cellulose acylate film include methods described in JP-A Nos. 11-246704, 2001-247717, and Japanese Patent Application No. 2003-379975. Rth can also be reduced by reducing the thickness of the cellulose acylate film. The thickness of the cellulose sylate film as the protective film for the first and second polarizing films is preferably 10 to 100 μm, more preferably 10 to 60 μm, and still more preferably 20 to 45 μm.

[Third retardation layer]
In the third retardation layer used in the present invention, the in-plane refractive indexes nx and ny are substantially equal, nx <nz, and the retardation Rth in the thickness direction is −100 nm to 0 nm. The third retardation layer preferably has no absorption in the visible light region, has a light transmittance of 80% or more, and has a small retardation based on birefringence. Specifically, the in-plane Re is preferably 0 to 30 nm, more preferably 0 to 15 nm, and even more preferably 0 to 5 nm. The retardation Rth in the thickness direction is preferably -80 to 0 nm, and more preferably -60 to 0 nm. Any film having this property can be preferably used, but from the viewpoint of durability of the polarizing film, a cellulose acylate or norbornene film is more preferable. Examples of a method for reducing Rth of the cellulose acylate film include methods described in JP-A Nos. 11-246704, 2001-247717, and Japanese Patent Application No. 2003-379975. Rth can also be reduced by reducing the thickness of the cellulose acylate film.

As described above, in the present invention, the third retardation layer may be used as a protective film for the first and second polarizing films. In such an embodiment, it is preferable to use a cellulose acylate film as the third retardation layer. The thickness of the cellulose acylate film used as the polarizing film protective film is preferably 10 to 100 μm, more preferably 10 to 60 μm, and still more preferably 20 to 45 μm.
Moreover, it is also possible to produce the third retardation layer by vertically aligning the rod-like liquid crystalline compound in the same manner as the second retardation layer.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Preparation of IPS mode liquid crystal cell 1>
As shown in FIG. 2, electrodes (2 and 3 in FIG. 1) are arranged on a glass substrate so that the distance between adjacent electrodes is 20 μm, and a polyimide film is used as an alignment film on the electrodes. A rubbing process was performed. The rubbing process was performed in the direction 4 shown in FIG. A polyimide film was provided on one surface of a separately prepared glass substrate, and a rubbing treatment was performed to obtain an alignment film. The two glass substrates are stacked and bonded so that the alignment films face each other, the distance between the substrates (gap; d) is 3.9 μm, and the rubbing directions of the two glass substrates are parallel. A nematic liquid crystal composition having a refractive index anisotropy (Δn) of 0.0769 and a dielectric anisotropy (Δε) of 4.5 was enclosed. The value of d · Δn of the liquid crystal layer was 300 nm.

<Production of First Retardation Layer 1, First Retardation Layer 2, and First Retardation Layer 3>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution. The solution was filtered using a filter paper (No. 63, manufactured by Advantech) having a retained particle diameter of 4 μm and a drainage time of 35 seconds at 5 kg / cm ² or less.

────────────────────────────────────
Cellulose acetate solution composition ────────────────────────────────────
Cellulose acetate having an acetylation degree of 60.9% (degree of polymerization: 300, Mn / Mw = 1.5) 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (second solvent) 54 parts by weight 1-butanol (third solvent) 11 parts by weight ──────────────────── ────────────────

  In another mixing tank, 8 parts by mass of the following retardation increasing agent A, 10 parts by mass of retardation increasing agent B, 0.28 parts by mass of silicon dioxide fine particles (average particle size: 0.1 μm), 80 parts by mass of methylene chloride And 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution (and a fine particle dispersion). The dope was prepared by mixing 474 parts by mass of the cellulose acetate solution with 40 parts by mass of the retardation increasing agent solution and stirring sufficiently.

Retardation raising agent A

Retardation raising agent B

  The obtained dope was cast using a band casting machine. A film having a residual solvent amount of 15% by mass was stretched transversely at a stretch ratio of 20% using a tenter under the conditions of 130 ° C., held at 50 ° C. for 30 seconds with the stretched width, and then clipped to remove cellulose. An acetate film was prepared. The residual solvent amount at the end of stretching was 5% by mass, and further dried to prepare a film with the residual solvent amount being less than 0.1% by mass.

  The film thus obtained (first retardation layer 1) had a thickness of 80 μm. About the produced 1st phase difference layer 1, Re is 70 nm by measuring the light incident angle dependence of Re using an automatic birefringence meter (KOBRA-21ADH, Oji Scientific Instruments Co., Ltd. product). It was found that Rth was 175 nm and Nz was 3.0.

  In another mixing tank, 16 parts by mass of the above-mentioned retardation increasing agent A, 8 parts by mass of retardation increasing agent B, 0.28 parts by mass of silicon dioxide fine particles (average particle size: 0.1 μm), 80 parts by mass of methylene chloride And 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution (and a fine particle dispersion). 45 parts by mass of the retardation increasing agent solution was mixed with 474 parts by mass of the cellulose acetate solution, and the dope was prepared by sufficiently stirring to form a film in the same manner as in the first retardation layer 1 described above. The film thus obtained (first retardation layer 2) had a thickness of 80 μm. About the produced 1st phase difference layer 2, Re is 60 nm by measuring the light incident angle dependence of Re using an automatic birefringence meter (KOBRA-21ADH, Oji Scientific Instruments Co., Ltd. product). It was found that Rth was 210 nm and Nz was 4.0.

  Into another mixing tank, 18 parts by mass of the retardation increasing agent A, 0.28 parts by mass of silicon dioxide fine particles (average particle size: 0.1 μm), 80 parts by mass of methylene chloride and 20 parts by mass of methanol were charged. Stirring while heating, a retardation increasing agent solution (and a fine particle dispersion) was prepared. The same as the first retardation layer 1 described above, except that 474 parts by mass of the cellulose acetate solution was mixed with 25 parts by mass of the retardation increasing agent solution, sufficiently stirred to prepare a dope, and the draw ratio was 23%. Filmed. The film thus obtained (first retardation layer 3) had a thickness of 80 μm. About the produced 1st phase difference layer 3, Re is 35 nm by measuring the light incident angle dependence of Re using an automatic birefringence meter (KOBRA-21ADH, the Oji Scientific Instruments company make). It was found that Rth was 135 nm and Nz was 4.4.

<Preparation of Second Retardation Layer 1, Second Retardation Layer 2, Second Retardation Layer 3, Second Retardation Layer 4, and Second Retardation Layer 5>
The surfaces of the manufactured first retardation layer 1, first retardation layer 2, and first retardation layer 3 are saponified, and a commercially available vertical alignment film (JALS-204R, Nippon Synthetic Rubber ( Co., Ltd.) was diluted 1: 1 with methyl ethyl ketone, and then 2.4 ml / m ^{2 was} applied with a wire bar coater. Immediately, it was dried with warm air of 120 ° C. for 120 seconds.

  Next, 3.8 g of the following rod-shaped liquid crystal compound, 0.06 g of photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy), 0.02 g of sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), A solution in which 0.002 g of the air interface side vertical alignment agent was dissolved in 9.2 g of methyl ethyl ketone was prepared. This solution was respectively applied to the alignment film side of the film on which the alignment film was formed with a wire bar having the count shown in the table below. This was affixed to a metal frame and heated in a constant temperature bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, the rod-shaped liquid crystal compound was crosslinked by UV irradiation for 20 seconds with a 120 W / cm high-pressure mercury lamp at 80 ° C., and then allowed to cool to room temperature to prepare a retardation layer.

Rod-shaped liquid crystal compound

Air interface side vertical alignment agent:

自動複屈折率計（ＫＯＢＲＡ−２１ＡＤＨ、王子計測機器（株）社製）を用いて、製作したフィルムのＲｅの光入射角度依存性を測定し、予め測定した支持体の寄与分を差し引くことによって、第２位相差層のみの光学特性を算出したところ、それぞれ第２位相差層１はＲｅが０ｎｍ、Ｒｔｈが−２２５ｎｍ、第２位相差層２はＲｅが０ｎｍ、Ｒｔｈが−１８０ｎｍ、第２位相差層３はＲｅが０ｎｍ、Ｒｔｈが−２９５ｎｍ、第２位相差層４はＲｅが０ｎｍ、Ｒｔｈが−１７０ｎｍ、第２位相差層５はＲｅが０ｎｍ、Ｒｔｈが−２９２ｎｍであって、いずれも棒状液晶が略垂直に配向していることを確認した。
同様にして、市販のセルロースアセテートフィルム（フジタックＴＤ８０ＵＦ、富士写真フイルム（株）製、Ｒｅ＝３ｎｍ、Ｒｔｈ＝４５ｎｍ）上に第２位相差層１を作製し、位相差フィルム６とした。

Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), measuring the light incident angle dependency of Re of the manufactured film, and subtracting the pre-measured contribution of the support When the optical properties of only the second retardation layer were calculated, Re was 0 nm and Rth was −225 nm for the second retardation layer 1, Re was 0 nm and Rth was −180 nm for the second retardation layer 2, The retardation layer 3 has Re of 0 nm and Rth of −295 nm, the second retardation layer 4 has Re of 0 nm and Rth of −170 nm, and the second retardation layer 5 has Re of 0 nm and Rth of −292 nm. It was also confirmed that the rod-like liquid crystal was aligned substantially vertically.
Similarly, a second retardation layer 1 was produced on a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 45 nm) to obtain a retardation film 6.

<Production of Polarizing Plate Protective Film 1>
The following composition was put into a mixing tank, stirred while heating to dissolve each component, and a cellulose acetate solution A was prepared.
<Composition of cellulose acetate solution A>
Cellulose acetate having a substitution degree of 2.86 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (second solvent) ) 54 parts by mass 1-butanol 11 parts by mass

The following composition was charged into another mixing tank, stirred while heating to dissolve each component, and an additive solution B-1 was prepared.
<Additive solution B-1 composition>
Methylene chloride 80 parts by weight Methanol 20 parts by weight Optical anisotropy reducing agent 40 parts by weight

A dope was prepared by adding 35 parts by mass of the additive solution B-1 to 477 parts by mass of the cellulose acetate solution A and stirring sufficiently. The dope was cast from a casting port onto a drum cooled to 0 ° C. The film is peeled off at a solvent content of 70% by mass, and both ends in the width direction of the film are fixed with a pin tenter (the pin tenter described in FIG. 3 of JP-A-4-1009), and the solvent content is 3-5% by mass. In this state, the film was dried while maintaining an interval at which the stretching ratio in the transverse direction (direction perpendicular to the machine direction) was 3%. Then, it further dried by conveying between the rolls of the heat processing apparatus, and produced the polarizing plate protective film 1 with a thickness of 80 μm.
Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the light incident angle dependence of Re was measured, and the optical characteristics were calculated. Re was 1 nm and Rth was 6 nm. I was able to confirm.

<Preparation of third retardation layers 1, 2, 3, 4>
When the third retardation layer 1 was produced in the same manner as the polarizing plate protective film 1 and the optical characteristics were calculated, it was confirmed that Re was 1 nm and Rth was 6 nm.
Further, the third retardation layers 2, 3, and 4 were prepared by the same procedure except that the mixing ratio of the cellulose acetate solution A and the additive solution B-1 was changed. 2, Re is 0.5 nm, Rth is −5 nm, the third retardation layer 3 is Re is 0.7 nm, Rth is −20 nm, and the third retardation layer 4 is Re is 2 nm and Rth is −40 nm. It could be confirmed.

<Preparation of polarizing plate A>
Next, iodine is adsorbed on the stretched polyvinyl alcohol film to produce a polarizing film, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 45 nm) is subjected to saponification treatment. A polarizing plate A was formed on one surface of the polarizing film using a polyvinyl alcohol adhesive.

<Preparation of polarizing plate B>
A polarizing film is produced by adsorbing iodine to a stretched polyvinyl alcohol film, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) is subjected to saponification treatment, using a polyvinyl alcohol adhesive, A polarizing plate B was formed on both sides of the polarizing film.

<Preparation of polarizing plate C>
A polarizing film was produced in the same manner, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was subjected to saponification treatment and attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. . In the same manner, the polarizing plate protective film 1 manufactured as described above was attached to the other side of the polarizing film to form a polarizing plate C.

<Preparation of polarizing plate D>
A polarizing film was produced in the same manner, and a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was subjected to saponification treatment and attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. . In the same manner, a commercially available cellulose acetate film (Fujitac T40UZ, manufactured by Fuji Photo Film Co., Ltd., Re = 1 nm, Rth = 35 nm) was saponified, and the other side of the polarizing film was coated with a polyvinyl alcohol adhesive. A pasting polarizing plate D was formed.

Using these polarizing plates, a liquid crystal display device was produced by the method described below, and the color change was evaluated.
<Evaluation of color change and light leakage>
For the color measurement, a commercially available liquid crystal viewing angle and chromaticity characteristic measuring device Ezcom (manufactured by ELDIM) was used, and a commercially available liquid crystal display device 32Z1000 (manufactured by Toshiba) was used as the backlight.
For a black display liquid crystal cell, the chromaticity is measured over all azimuth angles at a polar angle of 60 degrees, the difference U between the maximum value and the minimum value of the chromaticity coordinates u ′, and the maximum value and the minimum value of the chromaticity coordinates v ′. From the difference V, U + V was calculated, and the larger the number, the greater the color change.
As for leakage light, the luminance was measured over all azimuth angles at a polar angle of 60 degrees, and the viewing angle was sufficiently compensated if the maximum luminance L60 therein was within 5 cd / m ² .
The evaluation criteria are summarized below.
About color ◎: U + V ≦ 0.20
Δ: 0.20 <U + V ≦ 0.22
X: 0.22 <U + V

[Example 1]
Using the polyvinyl alcohol-based adhesive for the polarizing plate A, the produced retardation film 1 is formed so that the first retardation layer 1 side is the polarizing film side and the transmission axis of the polarizing film and the first retardation layer 1 A polarizing plate 1 was prepared by pasting on the side of the polarizing film where the cellulose acetate film was not pasted so that the slow axis was parallel.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 1 is parallel to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 1). The polarizing plate 1 was affixed so that the axis was parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the surface of the second retardation layer 1 was on the liquid crystal cell side.
Subsequently, the third retardation layer 4 is bonded to the polarizing plate protective film 1 side of the polarizing plate C using an adhesive, and the third retardation layer 4 is on the liquid crystal cell side and the polarizing plate 1 Were pasted in a crossed Nicol arrangement to produce a liquid crystal display device. The color change U + V during black display of the liquid crystal display device thus produced was measured and found to be 0.19. Further, the leakage light at this time was 1.5 cd / m ² , and the viewing angle was sufficiently compensated.

[Example 2]
Using the polyvinyl alcohol-based adhesive for the polarizing plate A, the produced retardation film 3 is formed so that the first retardation layer 2 side is the polarizing film side and the transmission axis of the polarizing film and the first retardation layer 1 A polarizing plate 2 was prepared by pasting the polarizing film on the side where the cellulose acetate film was not pasted so that the slow axis was parallel.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 1 is parallel to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 1). The polarizing plate 2 was attached so that the axis was parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation layer 3 side was the liquid crystal cell side.
Subsequently, the third retardation layer 3 is bonded to the polarizing film of the polarizing plate A using an adhesive, and the third retardation layer 3 side is the liquid crystal cell side, and the polarizing plate 2 is crossed Nicol. The liquid crystal display device was manufactured by pasting so as to be arranged. The color change U + V during black display of the liquid crystal display device thus produced was measured and found to be 0.15. Further, the leakage light at this time was 1.2 cd / m ² , and the viewing angle was sufficiently compensated.

[Example 3]
The retardation film 3 is applied to the polarizing plate C, an acrylic resin so that the first retardation layer 2 side is the polarizing film side, and the transmission axis of the polarizing film and the slow axis of the first retardation layer 2 are parallel. The sticking polarizing plate 3 was produced using a system adhesive.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 2 is perpendicular to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 2). The polarizing plate 3 was attached so that the axis was perpendicular to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation layer 3 side was the liquid crystal cell side.
Subsequently, the third retardation layer 2 is bonded to the polarizing plate protective film 1 side of the polarizing plate C using an adhesive, and the third retardation layer 2 is on the liquid crystal cell side and the polarizing plate 1 Were pasted in a crossed Nicol arrangement to produce a liquid crystal display device. The color change U + V at the time of black display of the liquid crystal display device thus produced was measured and found to be 0.17. The leakage light at this time was 0.8 cd / m ² and the viewing angle was sufficiently compensated.

[Example 4]
The retardation film 3 is applied to the polarizing plate B, and an acrylic resin is used so that the first retardation layer 2 side is the polarizing film side and the transmission axis of the polarizing film is parallel to the slow axis of the first retardation layer 2. The sticking polarizing plate 3 was produced using a system adhesive.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 2 is parallel to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 2). The polarizing plate 3 was attached such that the axis was parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation layer 3 side was the liquid crystal cell side.
Subsequently, the third retardation layer 2 is bonded to the polarizing plate protective film 1 side of the polarizing plate B using an adhesive, and the third retardation layer 2 is on the liquid crystal cell side and the polarizing plate 1 Were pasted in a crossed Nicol arrangement to produce a liquid crystal display device. The color change U + V during black display of the liquid crystal display device thus produced was measured and found to be 0.25. Further, the leakage light at this time was 1.6 cd / m ² , and the viewing angle was sufficiently compensated.

[Comparative Example 1]
Using the polyvinyl alcohol-based adhesive for the polarizing plate A, the produced retardation film 3 is formed so that the first retardation layer 2 side is the polarizing film side and the transmission axis of the polarizing film and the first retardation layer 1 A polarizing plate 2 was prepared by pasting the polarizing film on the side where the cellulose acetate film was not pasted so that the slow axis was parallel.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 1 is parallel to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 1). The polarizing plate 2 was attached so that the axis was parallel to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation layer 3 side was the liquid crystal cell side.
Subsequently, the third retardation layer 1 is bonded to the polarizing plate B using an adhesive, and the third retardation layer 1 side is on the liquid crystal cell side, and the polarizing plate 2 is in a crossed Nicol arrangement. Thus, a liquid crystal display device was produced. The color change U + V during black display of the liquid crystal display device thus produced was measured and found to be 0.22. Further, the leaked light at this time was 2.3 cd / m ² , and the viewing angle compensation was sufficient.

[Comparative Example 2]
The retardation film 6 is used for the polarizing plate B, and an acrylic resin adhesive is used so that the transmission axis of the polarizing film and the slow axis of the first retardation layer 2 are orthogonal to each other so that the TD80 side is the polarizing film side. Thus, an affixed polarizing plate 3 was produced.

This is applied to one of the IPS mode liquid crystal cells 1 produced above so that the slow axis of the first retardation layer 2 is perpendicular to the rubbing direction of the liquid crystal cell (that is, the slow phase of the first retardation layer 2). The polarizing plate 3 was attached so that the axis was perpendicular to the slow axis of the liquid crystal molecules of the liquid crystal cell during black display) and the second retardation layer 3 side was the liquid crystal cell side.
Subsequently, the third retardation layer 2 is bonded to the polarizing plate protective film 1 side of the polarizing plate B using an adhesive, and the third retardation layer 2 is on the liquid crystal cell side and the polarizing plate 1 Were pasted in a crossed Nicol arrangement to produce a liquid crystal display device. The color change U + V during black display of the liquid crystal display device thus produced was measured and found to be 0.23. Further, the leaked light at this time was 5.2 cd / m ² , and the viewing angle compensation was insufficient.

The results of color and leakage light are summarized in Table 1.
Further, FIG. 4 shows a u′-v ′ graph in all azimuth angles at a polar angle of 60 degrees for the liquid crystal display device of Example 4 and for the liquid crystal display device of Comparative Example 1 in FIG.

It is the schematic which shows an example of the liquid crystal display device of this invention. It is the schematic which shows the pixel area example of the liquid crystal display device of this invention. It is the schematic which shows the other example of the liquid crystal display device of this invention. 14 is a u′-v ′ graph of the liquid crystal display device of Example 4. 10 is a u′-v ′ graph of the liquid crystal display device of Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal element pixel area 2 Pixel electrode 3 Display electrode 4 Rubbing direction 5a, 5b Director of liquid crystal compound at the time of black display 6a, 6b Director of liquid crystal compound at the time of white display 7a, 7b, 19a, 19b Protective film for polarizing film 8, 20 Polarizing film 9, 21 Absorption axis 10 of polarizing film First retardation layer 11 Slow axis 12 of first retardation layer Second retardation layer 13, 17 Cell substrate 14 Cell substrate rubbing direction 15 Liquid crystal layer 16 Liquid crystal Slow axis direction of the layer 18 Third retardation layer

Claims (7)

Including at least a first polarizing film, a first retardation layer, a second retardation layer, a third retardation layer, and a liquid crystal cell in which a liquid crystal layer made of a nematic liquid crystal material is sandwiched between a pair of substrates, A liquid crystal display device in which liquid crystal molecules of the nematic liquid crystal material are aligned parallel to the surfaces of the pair of substrates when displaying black in a cell,
The in-plane retardation Re of the first retardation layer is 20 nm to 150 nm, and the value Nz defined by Nz = Rth / Re + 0.5 is 1.5 to 7,
The in-plane refractive indexes nx and ny of the second retardation layer are substantially equal, nx <nz, and the retardation Rth in the thickness direction is −80 nm to −400 nm,
The in-plane refractive indices nx and ny of the third retardation layer are substantially equal, nx <nz, and the retardation Rth in the thickness direction is −100 nm to 0 nm, and
A liquid crystal display device in which a transmission axis of a first polarizing film is parallel to a slow axis direction of liquid crystal molecules during black display of a liquid crystal cell. The first polarizing film, the first retardation layer, the second retardation layer, the liquid crystal cell, and the third retardation layer are arranged in this order, and the slow axis of the first retardation layer is The liquid crystal display device according to claim 1, wherein the liquid crystal display device is substantially parallel to a transmission axis of the first polarizing film. And a second polarizing film having a transmission axis orthogonal to the transmission axis of the first polarizing film, wherein the first and second polarizing films are the first retardation layer, the second retardation layer, and the liquid crystal. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is disposed so as to sandwich the cell. It has a pair of protective films arranged with the first polarizing film and / or the second polarizing film in between, and the thickness direction retardation Rth of the protective film closer to the liquid crystal layer of the pair of protective films is 40 nm. The liquid crystal display device according to claim 1, wherein: The first polarizing film and / or the second polarizing film has a protective film on the opposite side to the surface close to the liquid crystal layer, and the first retardation layer, the second retardation film on the surface close to the liquid crystal layer. The liquid crystal display device according to claim 1, wherein any one of the phase difference layer and the third phase difference layer is in contact. A pair of protective films disposed between the first polarizing film and / or the second polarizing film, wherein the protective film on the side close to the liquid crystal layer is a cellulose acylate film or a norbornene-based film The liquid crystal display device according to any one of claims 1 to 3. The liquid crystal display device according to claim 1, wherein the second retardation layer has a retardation layer containing a rod-like liquid crystal compound that is substantially vertically aligned.

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