JP2008020670A - Liquid crystal panel and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display having less light leakages in oblique directions and less color shifts in oblique directions, when a black image is displayed. <P>SOLUTION: A liquid crystal panel is used, which is provided with at least a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, a layered film (A) disposed in between the liquid crystal cell and the first polarizer and a retardation film (B) disposed in between the layered film (A) and the second polarizer and wherein the layered film (A) includes a retardation film (a<SB>1</SB>), where a refractive index elliptical body exhibits the relation nx>ny≥nz and a retardation film (a<SB>2</SB>), where a refractive index elliptical body exhibits the relation nz≥nx>ny and in the retardation film (B), a refractive index elliptical body exhibits the relation nx=ny>nz. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device with improved display characteristics.

A liquid crystal display device (hereinafter referred to as LCD) is an element that displays characters and images using the electro-optical characteristics of liquid crystal molecules. One of the driving modes of the LCD is a vertical alignment (VA) mode. Conventionally, a VA mode LCD has a problem that, for example, when a black image is displayed, when the screen is viewed from an oblique direction, the light from the backlight leaks and the contrast decreases. Furthermore, when the screen is viewed from an oblique direction, there is a problem that the color changes greatly (also referred to as color shift). In order to solve these problems, for example, a liquid crystal panel using a laminated film in which a negative uniaxial retardation film (nx = ny> nz) is laminated on the surface of a retardation film containing a norbornene-based resin is disclosed. (For example, refer to Patent Document 1). However, in the liquid crystal display device including the conventional liquid crystal panel, the drawbacks of backlight light leakage and color shift are not sufficiently improved. Therefore, improvement of this subject is desired.
JP-A-11-095208

  An object of the present invention is to provide a liquid crystal display device in which, when a black image is displayed, light leakage in the oblique direction and color shift in the oblique direction are small.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following liquid crystal panel, and have completed the present invention.

The liquid crystal panel of the present invention includes a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, and the liquid crystal cell. A laminated film (A) disposed between the first polarizer and the retardation film (B) disposed between the laminated film (A) and the second polarizer. Prepared,
The laminated film (A) includes a retardation film (a ₁ ) in which the refractive index ellipsoid has a relationship of nx> ny ≧ nz, and a retardation film (a) in which the refractive index ellipsoid has a relationship of nz ≧ nx> ny. ₂ ) and
In the retardation film (B), the refractive index ellipsoid shows a relationship of nx = ny> nz.

  In a preferred embodiment, the liquid crystal cell includes liquid crystal molecules aligned in a homeotropic alignment.

  In a preferred embodiment, the slow axis direction of the laminated film (A) is substantially perpendicular to the absorption axis direction of the first polarizer.

  In a preferred embodiment, the in-plane retardation value (Re [590]) at a wavelength of 590 nm of the laminated film (A) is larger than the in-plane retardation value (Re [480]) at a wavelength of 480 nm.

In a preferred embodiment, the retardation wavelength dispersion value of the film (B) and (D _B), the difference between the laminated wavelength dispersion value of the film _{(A) (D A) (} D B -D A) is 0. 05 or more:
Here, the chromatic dispersion value (D _A ) is a value calculated from the equation; Re [480] / Re [590], and Re [480] and Re [590] are in-plane at wavelengths of 480 nm and 590 nm, respectively. The chromatic dispersion value (D _B ) is a value calculated from the equation; R40 [480] / R40 [590], and R40 [480] and R40 [590] have wavelengths of 480 nm and 480 nm, respectively. It is a phase difference value measured by tilting by 40 degrees from the normal direction at 590 nm.

In a preferred embodiment, the slow axis direction of the retardation film (a ₁ ) is substantially perpendicular to the slow axis direction of the retardation film (a ₂ ).

In a preferred embodiment, the retardation film (a ₁ ) is disposed between the first polarizer and the retardation film (a ₂ ).

In a preferred embodiment, the in-plane retardation value (Re ₁ [590]) of the retardation film (a ₁ ) at a wavelength of 590 nm is larger than Re ₂ [590] of the retardation film (a ₂ ). .

In a preferred embodiment, the in-plane retardation value (Re ₁ [590]) of the retardation film (a ₁ ) at a wavelength of 590 nm and the in-plane retardation value of the retardation film (a ₂ ) at a wavelength of 590 nm. (Re ₂ [590]) difference between the _{(Re 1 [590] -Re 2} [590]) is a 100 nm to 200 nm.

In a preferred embodiment, the retardation film (a ₁ ) contains a norbornene resin.

In a preferred embodiment, the retardation film (a ₂ ) contains a thermoplastic resin exhibiting negative birefringence.

  In a preferred embodiment, the thermoplastic resin exhibiting negative birefringence is a styrene / maleic anhydride copolymer, a styrene / (meth) acrylonitrile copolymer, a styrene / (meth) acrylate copolymer, a styrene / It is a maleimide copolymer, a vinyl ester / maleimide copolymer, or an olefin / maleimide copolymer.

In a preferred embodiment, the in-plane birefringence (Δn _xy [590]) of the retardation film (a ₂ ) at a wavelength of 590 nm is 0.002 or more.

  In a preferred embodiment, the retardation film (B) contains a polyimide resin.

  According to another aspect of the present invention, a liquid crystal display device is provided. This liquid crystal display device includes the liquid crystal panel described above.

  According to the present invention, by using a specific laminated film and retardation film, it is possible to provide a liquid crystal display device having small light leakage in the oblique direction and small color shift in the oblique direction when a black image is displayed. it can.

〔Definition of terms〕
Definitions of terms and symbols in the present specification are as follows.
(1) Refractive index (nx, ny, nz):
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). , “Nz” is the refractive index in the thickness direction.
(2) In-plane retardation value:
The in-plane retardation value (Re [λ]) refers to the in-plane retardation value of the film at a wavelength λ (nm) at 23 ° C. Re [λ] is a value calculated by Re [λ] = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Phase difference value of 40 degree inclination:
R40 [λ] refers to a retardation value measured by tilting 40 degrees from the normal direction of the film at a wavelength λ (nm) at 23 ° C.
(4) In-plane birefringence:
The in-plane birefringence (Δn _xy [λ]) is a value calculated by Re [λ] / d.
(5) Thickness direction retardation value:
The retardation value in the thickness direction (Rth [λ]) refers to the retardation value in the thickness direction of the film at 23 ° C. and the wavelength λ (nm). Rth [λ] is a value calculated by Rth [λ] = (nx−nz) × d, where d (nm) is the thickness of the film.
(6) Birefringence index in the thickness direction:
The birefringence (Δn _xz [λ]) in the thickness direction is a value calculated by Rth [λ] / d.
(7) Nz coefficient:
The Nz coefficient is a value calculated by Rth [590] / Re [590].
(8) Chromatic dispersion value:
The chromatic dispersion values (D _A , D ₁ , D ₂ ) are values calculated from the equation: Re [480] / Re [590]. The chromatic dispersion value (D _B ) is a value calculated from the formula: R40 [480] / R40 [590].
(9) In the present specification, the description “nx = ny” or “ny = nz” includes not only the case where they are completely the same, but also the case where they are substantially the same. Therefore, for example, even when nx = ny, the case where Re [590] is less than 10 nm is included.
(10) In this specification, “substantially orthogonal” includes a case where an angle formed by two optical axes is 90 ° ± 2 °, and preferably 90 ° ± 1 °. “Substantially parallel” includes a case where an angle formed by two optical axes is 0 ° ± 2 °, and preferably 0 ° ± 1 °.
(11) In this specification, for example, the subscript “A” represents the laminated film (A), and the subscript “B” represents the retardation film (B). The subscript “1” represents the retardation film (a ₁ ), and the subscript “2” represents the retardation film (a ₂ ).

<A. Overview of LCD panel>
The liquid crystal panel of the present invention includes a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, and the liquid crystal cell. A laminated film (A) disposed between the first polarizer and the retardation film (B) disposed between the laminated film (A) and the second polarizer. Prepare. The laminated film (A) includes a retardation film (a ₁ ) in which the refractive index ellipsoid shows a relationship of nx> ny ≧ nz and a retardation film (a) in which the refractive index ellipsoid shows a relationship of nz ≧ nx> ny. ₂ ) and. In the retardation film (B), the refractive index ellipsoid shows a relationship of nx = ny> nz.

In the present invention, the laminated film (A) has a wavelength dispersion with a phase difference suitable for optically compensating a liquid crystal cell as compared with a single phase difference film (a ₁ ) or phase difference film (a ₂ ). Show the characteristics. As a result, in the liquid crystal display device including the laminated film (A), the light leakage in the oblique direction and the color shift in the oblique direction are remarkably improved as compared with the conventional liquid crystal display device.

  A preferred embodiment of the liquid crystal panel of the present invention will be described with reference to FIGS. It should be noted that, for the sake of easy understanding, the ratios of the vertical, horizontal, and thickness of the constituent members in FIGS. FIG. 1 is a schematic cross-sectional view of a liquid crystal panel according to a first embodiment of the present invention. The liquid crystal panel 100 includes a first polarizer 21, a laminated film (A) 31, a liquid crystal cell 10, a retardation film (B) 32, and a second polarizer 22, at least in this order. In the liquid crystal panel 100, the retardation film (B) 32 is disposed between the liquid crystal cell 10 and the second polarizer 22.

  FIG. 2 is a schematic cross-sectional view of a liquid crystal panel according to the second embodiment of the present invention. The liquid crystal panel 101 includes a first polarizer 21, a laminated film (A) 31, a retardation film (B) 32, a liquid crystal cell 10, and a second polarizer 22 in this order. In the liquid crystal panel 101, the retardation film (B) 32 is disposed between the liquid crystal cell 10 and the laminated film (A) 31.

  In practice, an optional protective layer or surface treatment layer may be disposed on the side of the first and / or second polarizer opposite to the side having the liquid crystal cell. Further, an arbitrary adhesive layer may be provided between the constituent members of the liquid crystal panel. The “adhesive layer” refers to a layer that joins surfaces with adjacent members and integrates them with practically sufficient adhesive force and adhesion time. Examples of the material for forming the adhesive layer include an adhesive, a pressure-sensitive adhesive, and an anchor coating agent. The adhesive layer may have a multilayer structure in which an anchor coating agent is formed on the surface of an adherend and an adhesive layer or a pressure-sensitive adhesive layer is formed thereon. Further, it may be a thin layer (also referred to as a hairline) that cannot be visually recognized. Hereinafter, although the detail of the structural member of this invention is demonstrated, this invention is not limited only to the following specific embodiment.

<B. Liquid crystal cell>
The liquid crystal cell preferably includes a pair of substrates and a liquid crystal layer as a display medium sandwiched between the pair of substrates. One substrate (active matrix substrate) includes a switching element (typically a TFT) for controlling the electro-optical characteristics of the liquid crystal, a scanning line for supplying a gate signal to the active element, and a signal line for supplying a source signal. Provided. The other substrate (color filter substrate) is provided with a color filter.

  The color filter may be provided on the active matrix substrate. Alternatively, when an RGB three-color light source (which may further include a multicolor light source) is used as the illumination means of the liquid crystal display device as in the field sequential method, the color filter can be omitted. The distance between the two substrates is controlled by a spacer. For example, an alignment film made of polyimide is provided on the side of each substrate in contact with the liquid crystal layer. Alternatively, for example, when the initial alignment of liquid crystal molecules is controlled using a fringe electric field formed by a patterned transparent electrode, the alignment film can be omitted.

  The liquid crystal cell preferably includes liquid crystal molecules aligned in a homeotropic alignment. In this specification, “homeotropic alignment” means a state in which the alignment vector of liquid crystal molecules is aligned perpendicularly (in the normal direction) to the substrate plane as a result of the interaction between the alignment-treated substrate and the liquid crystal molecules. Refers to things. The homeotropic alignment includes a case where the alignment vector of the liquid crystal molecules is slightly inclined with respect to the normal direction of the substrate, that is, a case where the liquid crystal molecules have a pretilt. When the liquid crystal molecules have a pretilt, the pretilt angle (angle from the substrate normal) is preferably 5 ° or less. By setting the pretilt angle in the above range, a liquid crystal display device with a high contrast ratio can be obtained.

  In the liquid crystal cell, the refractive index ellipsoid preferably has a relationship of nz> nx = ny. Examples of driving modes using a liquid crystal cell in which a refractive index ellipsoid has a relationship of nz> nx = ny include a vertical alignment (VA) mode, a twisted nematic (TN) mode, and a vertical alignment type / electric field control birefringence. (ECB) mode, optical compensation birefringence (OCB) mode, etc. are mentioned. Preferably, the liquid crystal cell is in a vertical alignment (VA) mode.

  The VA mode liquid crystal cell utilizes a voltage-controlled birefringence effect, and makes liquid crystal molecules aligned in a homeotropic alignment respond to the substrate with an electric field in a normal direction in the absence of an electric field. Specifically, as described in, for example, Japanese Patent Application Laid-Open No. 62-210423 and Japanese Patent Application Laid-Open No. 4-153621, in the case of a normally black method, liquid crystal molecules are formed on a substrate in the absence of an electric field. Therefore, when the upper and lower polarizing plates are arranged orthogonally, a black display can be obtained. On the other hand, in the presence of an electric field, the liquid crystal molecules operate so as to tilt in a 45 ° azimuth direction with respect to the absorption axis of the polarizing plate, whereby the transmittance increases and white display is obtained.

  The VA mode liquid crystal cell can be multi-domained by using a substrate having slits formed on electrodes or a substrate having projections formed on the surface as described in JP-A-11-258605, for example. It may be what you did. Such liquid crystal cells include, for example, ASV (Advanced Super View) mode manufactured by Sharp Corporation, PVA (Patterned Vertical Alignment) mode manufactured by Samsung Electronics Co., Ltd., and SURVIVEL (Super Ranged View VieWing by Super San Francisco, Ltd.). ) Mode.

Rth _LC [590] of the liquid crystal cell in the absence of an electric field is preferably −500 nm to −200 nm, more preferably −400 nm to −200 nm. The Rth _LC [590] is appropriately set depending on the birefringence of the liquid crystal molecules and the cell gap. The cell gap (substrate interval) of the liquid crystal cell is usually 1.0 μm to 7.0 μm.

  As the liquid crystal cell, the one mounted on a commercially available liquid crystal display device may be used as it is. Commercially available liquid crystal display devices including VA mode liquid crystal cells include, for example, Sharp Corporation liquid crystal television product name “AQUIS series”, Sony liquid crystal television product name “BRAVIA series”, and SUMSUNG 32V type wide display. Liquid crystal television product name “LN32R51B”, Nanao Co., Ltd. liquid crystal television product name “FORIS SC26XD1”, AU Optronics liquid crystal television product name “T460HW01”, and the like.

<C. Polarizer>
In this specification, a “polarizer” refers to an element that can convert natural light or polarized light into arbitrary polarized light. The first and second polarizers used in the present invention preferably convert natural light or polarized light into linearly polarized light. Such a polarizer has a function of transmitting one polarized light component when incident light is divided into two orthogonal polarized light components, and absorbing, reflecting, and scattering the other polarized light component. At least one function selected from the functions to be performed. The first and second polarizers may be the same or different.

  The first and second polarizers preferably have a transmittance at a wavelength of 590 nm (also referred to as a single transmittance) of 45% or more and a degree of polarization at a wavelength of 590 nm of 99% or more. The theoretical upper limit is 50% for the single transmittance and 100% for the degree of polarization. By setting the single transmittance and the degree of polarization to the above conditions, a liquid crystal display device having a high contrast ratio in the front direction can be obtained.

  The absorption axis direction of the first polarizer is preferably substantially orthogonal to the absorption axis direction of the second polarizer. Preferably, the first polarizer is disposed on the viewing side of the liquid crystal cell, and the second polarizer is disposed on the side opposite to the viewing side of the liquid crystal cell.

  Arbitrary appropriate things can be selected for the 1st polarizer and the 2nd polarizer used for the present invention. The thicknesses of the first polarizer and the second polarizer are preferably 5 μm to 50 μm. The first polarizer and the second polarizer preferably include iodine and a polyvinyl alcohol resin. Such a polarizer can be usually obtained by dyeing a polymer film containing a polyvinyl alcohol-based resin as a main component with an iodine aqueous solution and further stretching it. The iodine content of the polarizer is preferably 2% to 5% by weight. By setting the iodine content in the above range, a polarizer having excellent optical characteristics can be obtained.

  The polyvinyl alcohol resin can be obtained by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester monomer. The saponification degree of the polyvinyl alcohol resin is preferably 95 mol% or more. The saponification degree can be determined according to JIS K 6726-1994. By using a polyvinyl alcohol resin having a saponification degree in the above range, a polarizer having excellent durability can be obtained.

  As the average degree of polymerization of the polyvinyl alcohol-based resin, an appropriate value can be appropriately selected according to the purpose. The average degree of polymerization is preferably 1200 to 3600. The average degree of polymerization can be determined according to JIS K 6726-1994.

  Any appropriate forming method can be adopted as a method for obtaining the polymer film containing the polyvinyl alcohol resin as a main component. Examples of the molding method include the method described in JP 2000-315144 A [Example 1].

  The polymer film containing the polyvinyl alcohol-based resin as a main component preferably contains a plasticizer and / or a surfactant. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. As said surfactant, a nonionic surfactant is mentioned, for example. The plasticizer and surfactant are used for the purpose of further improving the dyeability and stretchability of the polarizer.

  A commercially available film can be used as it is as the polymer film containing the polyvinyl alcohol resin as a main component. Examples of the polymer film mainly composed of a commercially available polyvinyl alcohol-based resin include, for example, “Kuraray Vinylon Film” manufactured by Kuraray Co., Ltd., “Toselo Vinylon Film” manufactured by Tosero Co., Ltd., Nippon Synthetic Chemical Industry Product name “Nippon Vinylon Film”, etc., may be mentioned.

  An example of a method for manufacturing a polarizer will be described with reference to FIG. FIG. 3 is a schematic view showing the concept of a typical production process of a polarizer used in the present invention. In this manufacturing method, a polymer film 301 containing a polyvinyl alcohol-based resin as a main component is fed out from a feeding unit 300 and is first immersed in an aqueous solution bath 310 containing iodine. At this time, the polymer film 301 is subjected to a swelling and dyeing process while tension is applied in the film longitudinal direction by rolls 311 and 312 having different speed ratios. Next, the polymer film is immersed in a bath 320 of an aqueous solution containing boric acid and potassium iodide, and subjected to a crosslinking treatment while tension is applied in the longitudinal direction of the film by rolls 321 and 322 having different speed ratios. Is done. The film subjected to crosslinking treatment is immersed in an aqueous solution bath 330 containing potassium iodide by rolls 331 and 332 and subjected to a water washing treatment. The polymer film that has been washed with water is dried by a drying means 340 and wound up by a winding unit 360. The draw ratio of the polarizer 350 is generally 5 to 7 times the original length.

<D. Laminated film (A)>
The laminated film (A) used in the present invention is disposed between the liquid crystal cell and the first polarizer. The laminated film (A) is preferably bonded to the surface of the first polarizer via an adhesive layer. The slow axis direction of the laminated film (A) is preferably substantially orthogonal to the absorption axis direction of the first polarizer.

The laminated film (A) includes a retardation film (a ₁ ) in which the refractive index ellipsoid shows a relationship of nx> ny ≧ nz and a retardation film (a) in which the refractive index ellipsoid shows a relationship of nz ≧ nx> ny. ₂ ) and. The laminated film (A) may include an arbitrary layer as long as it includes the retardation film (a ₁ ) and the retardation film (a ₂ ). The arbitrary layer is not particularly limited, and examples thereof include an optically isotropic film and an adhesive layer.

The thickness of the laminated film (A) is preferably 20 μm to 500 μm. The transmittance (T _A [590]) at a wavelength of 590 nm of the laminated film (A) is preferably 80% or more. Re _A [590] of the laminated film (A) is 10 nm or more, preferably 50 nm to 200 nm. By setting Re _A [590] in the above range, a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction can be obtained.

Preferably, the laminated film (A) has an in-plane retardation value (Re _A [590]) at a wavelength of 590 nm larger than an in-plane retardation value (Re _A [480]) at a wavelength of 480 nm. The so-called “reverse wavelength dispersion characteristic” is shown. The laminated film in-plane retardation value at a wavelength of 590nm of (A) and (Re _A [590]), the difference between the in-plane retardation value at a wavelength of _{480nm (Re A [480])} (ΔRe 590-480 = Re _A [590] -Re _A [480]) is preferably 2 nm or more, more preferably 4 nm to 80 nm, and particularly preferably 4 nm to 40 nm or more.

The wavelength dispersion value (D _A ) of the laminated film (A) is preferably less than 1.00, more preferably 0.70 to 0.98, and particularly preferably 0.75 to 0.88. . By setting D _A within the above range, a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction can be obtained.

The retardation wavelength dispersion value of the film (B) and (D _B), the difference between the laminated wavelength dispersion value of the film _{(A) (D A) (} D B -D A) is preferably 0.05 or more More preferably 0.05 to 0.40, and particularly preferably 0.08 to 0.30. By setting D _B -D _A in the above range, for example, optimal optical compensation can be performed on a liquid crystal cell including liquid crystal molecules aligned in a homeotropic alignment.

<D-1. Retardation film (a ₁ )>
In the retardation film (a ₁ ) used in the present invention, the refractive index ellipsoid shows a relationship of nx> ny ≧ nz. In this specification, “showing a relationship of nx> ny ≧ nz” means showing a relationship of nx> ny = nz or showing a relationship of nx>ny> nz. The thickness of the retardation film (a ₁ ) is preferably 10 μm to 200 μm.

The arrangement position and angle of the retardation film (a ₁ ) can be appropriately determined according to the purpose. Preferably, the slow axis direction of the retardation film (a ₁ ) is substantially perpendicular to the slow axis direction of the retardation film (a ₂ ). Preferably, the slow axis direction of the retardation film (a ₁ ) is substantially perpendicular to the absorption axis direction of the first polarizer. By setting the arrangement position and angle of the retardation film (a ₁ ) as described above, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

Preferably, the retardation film (a ₁ ) is disposed between the first polarizer and the retardation film (a ₂ ). Such an arrangement is particularly preferable when the retardation film (a ₁ ) contains a norbornene resin and the retardation film (a ₂ ) contains a styrene resin and / or a maleimide resin. Since the norbornene-based resin is often superior in mechanical strength to the styrene-based resin and / or maleimide-based resin, the retardation film (a ₁ ) is applied to a polarizer having a relatively large dimensional change depending on humidity and temperature. A liquid crystal panel excellent in durability can be obtained by arranging closer.

Re ₁ [590] of the retardation film (a ₁ ) is 10 nm or more, preferably 200 nm to 800 nm, and more preferably 250 nm to 800 nm. By setting Re ₁ [590] in the above range, a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction can be obtained.

Preferably, Re ₁ [590] of the retardation film (a ₁ ) is larger than Re ₂ [590] of the retardation film (a ₂ ). The difference between the Re ₂ [590] of Re ₁ [590] and the retardation film of the retardation film _{(a 1) (a 2)} (Re 1 [590] -Re 2 [590]) is preferably 100nm It is -200 nm, More preferably, it is 100 nm -180 nm.

The chromatic dispersion value (D ₁ ) of the retardation film (a ₁ ) is preferably 0.90 to 1.10, and more preferably 0.95 to 1.05. Preferably, the retardation wavelength dispersion value of the film (a ₁₎ (D _1), said retardation wavelength dispersion value of the film (a ₂₎ (D ₂₎ smaller than. The retardation wavelength dispersion value of the film (a ₂₎ and (D _2), the difference of the retardation wavelength dispersion value of the film (a ₁₎ and _{(D 1) (D 2 -D} 1) is preferably 0. It is 01 or more, More preferably, it is 0.02-0.08. The D ₂ -D ₁ in the above range, the laminated film (A) shows a characteristic phase difference longer wavelength is large (so-called reverse wavelength dispersion characteristics).

Rth ₁ [590] of the retardation film (a ₁ ) can be appropriately set. When the refractive index ellipsoid of the retardation film (a ₁ ) shows a relationship of nx> ny = nz, Re ₁ [590] and Rth ₁ [590] are substantially equal. In this case, the retardation film (a ₁ ) preferably satisfies the formula: | Rth ₁ [590] −Re ₁ [590] | <10 nm.

When the refractive index ellipsoid of the retardation film (a ₁ ) shows a relationship of nx>ny> nz, Rth ₁ [590] is larger than Re ₁ [590]. In this case, the difference between Rth ₁ [590] and Re ₁ [590] (Rth ₁ [590] −Re ₁ [590]) is preferably 10 nm to 100 nm, and more preferably 20 nm to 80 nm. By setting Rth ₁ [590] as described above, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

The Nz coefficient of the retardation film (a ₁ ) can be appropriately set. When the refractive index ellipsoid of the retardation film (a ₁ ) shows a relationship of nx> ny = nz, the Nz coefficient is preferably more than 0.9 and less than 1.1. When the refractive index ellipsoid of the retardation film (a ₁ ) exhibits a relationship of nx>ny> nz, the Nz coefficient is preferably 1.1 to 3.0, more preferably 1.1 to 2. .0. By setting the Nz coefficient in the above range, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

As a material for forming the retardation film (a ₁ ), any appropriate material can be adopted as long as the refractive index ellipsoid shows a relationship of nx> ny ≧ nz. The retardation film (a ₁ ) preferably contains at least one thermoplastic resin selected from the group consisting of norbornene resins, polycarbonate resins, cellulose resins, and polyester resins. In this case, the retardation film (a ₁ ) preferably contains 60 to 100 parts by weight of the thermoplastic resin with respect to 100 important parts of the total solid content.

  In the present specification, the “thermoplastic resin” includes a polymer having a polymerization degree of 20 or more and a large weight average molecular weight (so-called high polymer), and further having a polymerization degree of 2 or more and less than 20. Includes low polymers (so-called oligomers) having a weight average molecular weight of about several thousand. In the present specification, the “resin” may be a homopolymer obtained from one type of monomer or a copolymer obtained from two or more types of monomers.

Preferably, the retardation film (a ₁ ) contains a norbornene resin. This is because the norbornene-based resin has a small absolute value of the photoelastic coefficient, and a liquid crystal display device that hardly causes optical unevenness can be obtained. In this specification, the “norbornene-based resin” refers to a (co) polymer obtained by using a norbornene-based monomer having a norbornene ring as a part or all of a starting material (monomer). The “(co) polymer” represents a homopolymer or a copolymer (copolymer).

The absolute value of the photoelastic coefficient at a wavelength of 590nm of the norbornene-based resin (C [590]) is preferably ^{1 × 10 -12 m 2 / N~20} × 10 -12 m 2 / N, more preferably 1 × a ^{10 -12 m 2 / N~10 × 10} -12 m 2 / N. If a retardation film having an absolute value of the photoelastic coefficient in the above range is used, a liquid crystal display device with small optical unevenness can be obtained.

In the norbornene-based resin, a norbornene-based monomer having a norbornene ring (having a double bond in the norbornane ring) is used as a starting material. In the state of the (co) polymer, the norbornene-based resin may or may not have a norbornane ring in the structural unit. In the (co) polymer state, the norbornene-based resin having a norbornane ring as a structural unit is, for example, tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dec-3-ene, 8-methyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene, 8-methoxycarbonyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene and the like. A norbornene-based resin having no norbornane ring as a structural unit in the (co) polymer state is, for example, a (co) polymer obtained using a monomer that becomes a 5-membered ring by cleavage. Examples of the monomer that becomes a 5-membered ring by cleavage include norbornene, dicyclopentadiene, 5-phenylnorbornene, and derivatives thereof. When the norbornene-based resin is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be.

  Examples of the norbornene resin include (a) a resin obtained by hydrogenating a ring-opening (co) polymer of a norbornene monomer, and (b) a resin obtained by addition (co) polymerization of a norbornene monomer. The ring-opening copolymer of the norbornene-based monomer is a resin obtained by hydrogenating a ring-opening copolymer of one or more norbornene-based monomers and α-olefins, cycloalkenes, and / or non-conjugated dienes. Includes. The resin obtained by addition copolymerization of the norbornene monomer includes a resin obtained by addition copolymerization of one or more norbornene monomers with α-olefins, cycloalkenes and / or non-conjugated dienes.

  A resin obtained by hydrogenating the ring-opening (co) polymer of the norbornene monomer is subjected to a metathesis reaction of the norbornene monomer or the like to obtain a ring-opening (co) polymer. It can be obtained by hydrogenation. Specifically, for example, the method described in paragraphs [0059] to [0060] of JP-A-11-116780, the method described in paragraphs [0035] to [0037] of JP-A-2001-350017, and the like. Can be mentioned. The resin obtained by addition (co) polymerization of the norbornene monomer can be obtained, for example, by the method described in Example 1 of JP-A No. 61-292601.

  The weight average molecular weight (Mw) of the norbornene resin is preferably 20,000 to 500,000 as measured by gel permeation chromatography (polystyrene standard) using a tetrahydrofuran solvent. The glass transition temperature (Tg) of the norbornene-based resin is preferably 120 ° C to 170 ° C. If it is said resin, it has the outstanding thermal stability and the film excellent in the drawability can be obtained. The glass transition temperature (Tg) is a value calculated by the DSC method according to JIS K7121.

  The retardation film (A) containing the norbornene resin can be obtained by any appropriate forming method. Preferably, the retardation film (A) containing the norbornene-based resin is obtained by subjecting a polymer film formed into a sheet shape by a solvent casting method or a melt extrusion method to a longitudinal uniaxial stretching method, a lateral uniaxial stretching method, It is produced by stretching by a biaxial stretching method or a longitudinal and lateral sequential biaxial stretching method. The temperature at which the polymer film is stretched (stretching temperature) is preferably 120 ° C to 200 ° C. Moreover, the magnification (drawing ratio) for stretching the polymer film is preferably more than 1 and 4 times or less.

  As the polymer film containing the norbornene resin, a commercially available film can be used as it is. Alternatively, a commercially available film subjected to secondary processing such as stretching and / or shrinking can be used. As a polymer film containing a commercially available norbornene resin, for example, Arton series (trade name; ARTON F, ARTON FX, ARTON D) manufactured by JSR Corporation, or ZEONOR series (trade name; ZEONOR Corporation) manufactured by Optes Co., Ltd. ZF14, ZEONOR ZF16) and the like.

The retardation film (a ₁ ) may further contain any appropriate additive. Examples of the additive include a plasticizer, a heat stabilizer, a light stabilizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, an antistatic agent, a compatibilizer, a crosslinking agent, and a thickener. Etc. The content of the additive is preferably more than 0 and 10 parts by weight or less with respect to 100 parts by weight of the main resin.

<D-2. Retardation film (a ₂ )>
In the retardation film (a ₂ ) used in the present invention, the refractive index ellipsoid shows a relationship of nz ≧ nx> ny. In this specification, “showing a relationship of nz ≧ nx> ny” means showing a relationship of nz = nx> ny or showing a relationship of nz>nx> ny.

The arrangement position and angle of the retardation film (a ₂ ) can be appropriately determined according to the purpose. Preferably, the slow axis direction of the retardation film (a ₂ ) is substantially perpendicular to the slow axis direction of the retardation film (a ₁ ). Preferably, the slow axis direction of the retardation film (a ₂ ) is substantially parallel to the absorption axis direction of the first polarizer. Further, preferably, the retardation film (a ₂ ) is disposed between the liquid crystal cell and the retardation film (a ₁ ). By setting the arrangement position and angle of the retardation film (a ₂ ) as described above, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

The thickness of the phase difference film (a ₂ ) is preferably 10 μm to 300 μm. The thickness of the retardation film _{(a 1) (d 1)} , the ratio of the thickness of the retardation Fi r arm _{(a 2) (d 2)} (d 1 / d 2) is preferably 0.5 to 3 More preferably, it is 0.8-2. By setting the thickness within the above range, a laminated film (A) exhibiting excellent wavelength dispersion characteristics can be obtained.

Re ₂ [590] of the retardation film (a ₂ ) is 10 nm or more, preferably 50 nm to 700 nm, more preferably 100 nm to 600 nm. The chromatic dispersion value (D ₂ ) of the retardation film (a ₂ ) is preferably 1.00 or more, more preferably 1.02 to 1.10. By setting Re ₂ [590] and D ₂ in the above ranges, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

Rth ₂ [590] of the retardation film (a ₂ ) can be appropriately set. When the refractive index ellipsoid of the retardation film (a ₂ ) shows a relationship of nz = nx> ny, the absolute value of Rth ₂ [590] is less than 10 nm. When the refractive index ellipsoid of the retardation film (a ₂ ) shows a relationship of nz>nx> ny, Rth ₂ [590] shows a negative value, preferably −50 nm to −10 nm, more preferably Is −30 nm to −10 nm. By setting Rth ₂ [590] as described above, it is possible to obtain a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction.

As a material for forming the retardation film (a ₂ ), any appropriate material can be adopted as long as the refractive index ellipsoid shows a relationship of nz ≧ nx> ny. The retardation film (a ₂ ) preferably contains a thermoplastic resin exhibiting negative birefringence. In this case, the retardation film (a ₂ ) preferably contains 60 to 100 parts by weight of the thermoplastic resin exhibiting the negative birefringence with respect to 100 important parts of the total solid content. The thermoplastic resin exhibiting negative birefringence can be obtained, for example, by addition polymerization of a styrene monomer or a maleimide monomer.

If the retardation film (a ₂ ) containing the thermoplastic resin exhibiting the negative birefringence is used, it is laminated on the retardation film (a ₁ ) and stretched in the same direction, whereby a refractive index ellipsoid. Shows a relationship of nz ≧ nx> ny, and a laminated film (A) whose slow axis is perpendicular to the slow axis of the retardation film (a ₁ ) can be produced at a time. There is.

  Any appropriate styrenic monomer may be selected. Examples of the styrene monomer include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, p-chloro styrene, p-nitro styrene, p-amino styrene, p-carboxyl styrene, and p-phenyl styrene. 2,5-dichlorostyrene, pt-butylstyrene and the like.

  Any appropriate monomer can be selected as the maleimide monomer. Examples of the maleimide monomer include N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (2-ethylphenyl) maleimide, N- (2-n -Propylphenyl) maleimide, N- (2-isopropylphenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-diethylphenyl) maleimide, N- (2,6-di-isopropyl) Phenyl) maleimide, N- (2-methyl-6-ethylphenyl) maleimide, N- (2-chlorophenyl) maleimide, N- (2,6-dibromophenyl) maleimide, N- (2-biphenyl) maleimide, N- (2-cyanophenyl) maleimide and the like. The maleimide monomer can be obtained from, for example, Tokyo Chemical Industry Co., Ltd.

  The thermoplastic resin exhibiting negative birefringence can be copolymerized with other monomers in order to improve brittleness and moldability. Examples of the other monomer include ethylene, propylene, 1-butene, isobutene, 1,3-butadiene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-hexene, acrylonitrile, and methyl acrylate. , Methyl methacrylate, maleic anhydride, vinyl acetate and the like.

  When the thermoplastic resin exhibiting negative birefringence is a copolymer of a styrene monomer and another monomer, the content of the styrene monomer is preferably 50 mol% to 80 mol%. When the thermoplastic resin exhibiting negative birefringence is a copolymer of a maleimide monomer and another monomer, the content of the maleimide monomer is preferably 2 mol% to 50 mol%. When the content of the thermoplastic resin exhibiting negative birefringence is in the above range, a film having excellent brittleness and moldability can be obtained.

  Preferably, the thermoplastic resin exhibiting negative birefringence is a styrene / maleic anhydride copolymer, a styrene / (meth) acrylonitrile copolymer, a styrene / (meth) acrylate copolymer, a styrene / maleimide copolymer. A polymer, a vinyl ester / maleimide copolymer, or an olefin / maleimide copolymer. These resins exhibit high negative birefringence and are excellent in heat resistance. These resins are described in, for example, NOVA Chemicals Japan Ltd. It can also be obtained from Arakawa Chemical Industries, Ltd.

  More preferably, the thermoplastic resin exhibiting negative birefringence has at least a repeating unit represented by the following general formula (I). Such a resin can be obtained by using, as a maleimide monomer as a starting material, N-phenyl substituted maleimide having a phenyl group having a substituent at least in the ortho position as an N substituent. Such a resin further exhibits high negative birefringence and is excellent in heat resistance and mechanical strength.

In the general formula (I), R _{1 to} R ₅ are each independently hydrogen, a halogen atom, a carboxylic acid, a carboxylic acid ester, a hydroxyl group, a nitro group, or a linear or branched group having 1 to 8 carbon atoms. Represents an alkyl group (wherein R ₁ and R ₅ are not hydrogen atoms at the same time), R ₆ and R ₇ represent hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, and n is 2 or more. Represents an integer.

  The weight average molecular weight (Mw) of the thermoplastic resin exhibiting negative birefringence is preferably a value measured by gel permeation chromatography (polystyrene standard) using a tetrahydrofuran solvent, preferably 20,000 to 500,000. It is. The glass transition temperature (Tg) of the thermoplastic resin exhibiting negative birefringence is preferably 110 ° C. to 185 ° C. If it is said resin, the film which showed the outstanding thermal stability and was excellent in the drawability may be obtained. The glass transition temperature (Tg) can be determined by a DSC method according to JIS K7121.

The retardation film (a ₂ ) containing the thermoplastic resin exhibiting negative birefringence can be obtained by any appropriate forming method. Preferably, the retardation film (a ₂ ) containing the thermoplastic resin exhibiting negative birefringence is obtained by subjecting a polymer film formed into a sheet shape by a solvent casting method or a melt extrusion method to a longitudinal uniaxial stretching method. The film is stretched by a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, or a longitudinal and transverse sequential biaxial stretching method. The temperature at which the polymer film is stretched (stretching temperature) is preferably 120 ° C to 200 ° C. Moreover, the magnification (drawing ratio) for stretching the polymer film is preferably more than 1 and 4 times or less.

Preferably, the laminate film (A) used in the present invention forms a laminate by coating a thermoplastic resin exhibiting negative birefringence on the surface of a polymer film containing a norbornene-based resin and drying. The laminate is produced by a method of stretching in at least one direction. According to such a method, a laminated film (A) including the retardation film (a ₂ ) having a large in-plane birefringence index (Δn _xy ) can be obtained.

Conventionally, a retardation film containing a thermoplastic resin exhibiting negative birefringence and having Δn _xy [590] of 0.002 or more has not been obtained. This is because a polymer film containing a thermoplastic resin exhibiting negative birefringence is less likely to cause a retardation value due to stretching compared to other resins, or it is difficult to stretch because the film itself is brittle. Because. For example, in order to obtain a retardation value necessary for optical compensation of a VA mode liquid crystal cell, a large stress must be applied to the film, which makes it difficult to produce such a retardation film.

According to the manufacturing method described above, it is Δn _xy [590] 0.002 or more, a retardation film containing a thermoplastic resin showing negative birefringence of (a ₂₎ can be actually manufactured. The in-plane birefringence (Δn _xy [590]) of the retardation film (a ₂ ) is preferably 0.002 to 0.008, more preferably 0.003 to 0.006.

The retardation film (a ₂ ) may further contain any appropriate additive. Examples of the additive include a plasticizer, a heat stabilizer, a light stabilizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, an antistatic agent, a compatibilizer, a crosslinking agent, and a thickener. Etc. The content of the additive is preferably more than 0 and 10 parts by weight or less with respect to 100 parts by weight of the main resin.

<E. Retardation Film (B)>
The retardation film (B) used in the present invention is disposed between the second polarizer and the liquid crystal cell. The retardation film (B) is preferably bonded to the second polarizer through an adhesive layer. In the retardation film (B), the refractive index ellipsoid shows a relationship of nx = ny> nz. The thickness of the retardation film (B) is preferably 0.5 μm to 200 μm. The transmittance (T [590]) at a wavelength of 590 nm of the retardation film (B) is preferably 90% or more.

Re _B [590] of the retardation film (B) is less than 10 nm, preferably 5 nm or less, and more preferably 3 nm or less. By setting Re _B [590] in the above range, a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction can be obtained.

Rth _B [590] of the retardation film (B) can be appropriately set according to the retardation value in the thickness direction of the liquid crystal cell. The Rth _B [590] is preferably 100 nm to 400 nm, more preferably 120 nm to 350 nm, and particularly preferably 150 nm to 300 nm. By setting Rth _B [590] in the above range, a liquid crystal display device with small light leakage in the oblique direction and small color shift in the oblique direction can be obtained.

  As a material for forming the retardation film (B), any appropriate material can be adopted as long as the refractive index ellipsoid shows a relationship of nx = ny> nz. The retardation film (B) preferably contains at least one thermoplastic resin selected from the group consisting of polyimide resins, cellulose resins, norbornene resins, polycarbonate resins, and polyamide resins. . The retardation film (B) preferably contains 60 to 100 parts by weight of the thermoplastic resin with respect to 100 important parts of the total solid content.

The retardation film (B) preferably contains a polyimide resin. When the polyimide resin is formed into a sheet by the solvent casting method, the refractive index ellipsoid shows a relationship of nx = ny> nz because the molecules are likely to be spontaneously oriented during the evaporation process of the solvent. The film can be made very thin. The thickness of the retardation film containing the polyimide resin is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm. The birefringence ( _Δnxz [590]) in the thickness direction of the retardation film containing the polyimide resin is preferably 0.01 to 0.12, more preferably 0.02 to 0.08. . Such a polyimide resin can be obtained, for example, by the method described in US Pat. No. 5,344,916.

  Preferably, the polyimide resin has a hexafluoroisopropylidene group and / or a trifluoromethyl group. More preferably, the polyimide resin has at least a repeating unit represented by the following general formula (II) or a repeating unit represented by the following general formula (III). Since polyimide resins containing these repeating units are excellent in solubility in general-purpose solvents, film formation by a solvent casting method is possible. Furthermore, a thin layer of the polyimide resin can be formed on a substrate having poor solvent resistance such as a triacetyl cellulose film without excessively eroding the surface.

In the general formulas (II) and (III), G and G ′ are a covalent bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, a C (CX ₃ ) ₂ group (here X is a halogen.), Each independently from the group consisting of CO, O, S, SO ₂ , Si (CH ₂ CH ₃ ) ₂ and N (CH ₃ ) groups. Each represents the same or different group.

  In the above general formula (II), L is a substituent, and e represents the number of substitutions. L is, for example, a halogen, an alkyl group having 1 to 3 carbon atoms, a halogenated alkyl group having 1 to 3 carbon atoms, a phenyl group, or a substituted phenyl group, and in a plurality of cases, they are the same or different. e is an integer from 0 to 3.

  In the general formula (III), Q is a substituent, and f represents the number of substitutions. Q is, for example, selected from the group consisting of hydrogen, halogen, alkyl group, substituted alkyl group, nitro group, cyano group, thioalkyl group, alkoxy group, aryl group, substituted aryl group, alkyl ester group, and substituted alkyl ester group And when Q is plural, they are the same or different. f is an integer from 0 to 4, and g and h are integers from 1 to 3, respectively.

  The said polyimide resin can be obtained by reaction of tetracarboxylic dianhydride and diamine, for example. The repeating unit of the general formula (II) is, for example, a tetracarboxylic acid having 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl as a diamine and at least two aromatic rings. It can be obtained by reaction with dianhydride. As the repeating unit of the above general formula (III), for example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanoic acid dianhydride is used as a tetracarboxylic dianhydride, and this is combined with an aromatic ring. It can be obtained by reacting with at least two diamines. The reaction may be, for example, chemical imidization that proceeds in two stages or thermal imidization that proceeds in one stage.

  Any appropriate tetracarboxylic dianhydride may be selected. Examples of the tetracarboxylic dianhydride include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanoic dianhydride and 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride. 2,3,3 ′, 4-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2,2′-dibromo-4,4 ′, 5 , 5′-biphenyltetracarboxylic dianhydride, 2,2′-bis (trifluoromethyl) -4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride, 4,4'-bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-bis (3 4-dicarboxyl Yl) sulfonic acid dianhydride, bis (2,3-carboxyphenyl) methane dianhydride, bis (3,4-carboxyphenyl) diethyl silane dianhydride, and the like.

  Any appropriate diamine may be selected. Examples of the diamine include 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 4,4′-diaminobiphenyl, 4,4′-diaminophenylmethane, 4,4 ′-( 9-fluorenylidene) -dianiline, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2′-dichloro-4,4′-diaminobiphenyl, 4,4′-diaminodiphenyl ether, 3,4′- Examples include diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenylthioether, and the like.

  The above polyimide-based resin is a polyethylene oxide standard weight average molecular weight (Mw) using a dimethylformamide solution (a solution obtained by adding 10 mM lithium bromide and 10 mM phosphoric acid to make a 1 L dimethylformamide solution). However, it is preferably 20,000 to 180,000. The imidization rate is preferably 95% or more. The imidation rate can be determined from an integral intensity ratio between a proton peak derived from polyamic acid, which is a polyimide precursor, and a proton peak derived from polyimide.

  The retardation film containing the polyimide resin can be obtained by any appropriate molding method. Preferably, the retardation film containing the polyimide resin is produced by molding into a sheet shape by a solvent casting method.

  The retardation film (B) may further contain any appropriate additive. Examples of the additive include a plasticizer, a heat stabilizer, a light stabilizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, an antistatic agent, a compatibilizer, a crosslinking agent, and a thickener. Etc. The content of the additive is preferably more than 0 and 10 parts by weight or less with respect to 100 parts by weight of the main resin.

  The retardation film (B) may be one using a liquid crystal composition. When a liquid crystal composition is used, the retardation layer includes a solidified layer or a cured layer of a liquid crystal composition containing a rod-like liquid crystal compound aligned in a planar alignment, or a discotic liquid crystal compound aligned in a columnar alignment. It includes a solidified layer or a cured layer of the liquid crystal composition. If a liquid crystal compound is used, a thin retardation film can be obtained because the birefringence in the thickness direction is large.

  A retardation film comprising a solidified layer or a cured layer of a liquid crystalline composition containing a rod-like liquid crystal compound aligned in the planar arrangement can be obtained, for example, by the method described in JP-A No. 2003-287623. In addition, a retardation film comprising a solidified layer or a cured layer of a liquid crystalline composition containing a discotic liquid crystal compounded soil aligned in the columnar arrangement can be obtained, for example, by the method described in JP-A-9-117983. it can.

<F. Protective layer>
Preferably, the liquid crystal panel of the present invention includes a protective layer on the side opposite to the liquid crystal cell side of the first polarizer and the second polarizer, respectively. The protective layer is used, for example, to prevent the polarizer from contracting or expanding or to prevent deterioration due to ultraviolet rays. The protective layers used for the first polarizer and the second polarizer may be the same or different.

  Any appropriate layer can be adopted as the protective layer. The thickness of the protective layer is preferably 20 μm to 100 μm. The transmittance (T [590]) at a wavelength of 590 nm of the protective layer is preferably 90% or more.

  Any appropriate material can be adopted as the material for forming the protective layer. Preferably, the protective layer contains at least one resin selected from the group consisting of a cellulose resin, a norbornene resin, and an acrylic resin. The polymer film containing the cellulose resin can be obtained, for example, by the method described in Example 1 of JP-A-7-112446. The polymer film containing the norbornene resin can be obtained, for example, by the method described in JP-A-2001-350017. The polymer film containing the acrylic resin can be obtained, for example, by the method described in Example 1 of JP-A-2004-198952.

  The protective layer may have a surface treatment layer on the side opposite to the side provided with the polarizer. The surface treatment layer can be appropriately treated according to the purpose. Examples of the surface treatment layer include treatment layers such as hard coat treatment, antistatic treatment, antireflection treatment (also referred to as antireflection treatment), and diffusion treatment (also referred to as antiglare treatment). These surface treatment layers are used for the purpose of preventing the screen from being soiled or damaged, or preventing the display image from becoming difficult to see due to the reflection of indoor fluorescent light or sunlight on the screen. In general, the surface treatment layer is formed by fixing a treatment agent for forming the treatment layer on the surface of a base film. The base film may also serve as the protective layer. Further, the surface treatment layer may have a multilayer structure in which, for example, a hard coat treatment layer is laminated on an antistatic treatment layer.

  As the protective layer, a commercially available polymer film provided with a surface treatment layer can be used as it is. Alternatively, a commercially available polymer film can be used after any surface treatment. Examples of the diffusion treatment (antiglare treatment) include AG150, AGS1, and AGS2 manufactured by Nitto Denko Corporation. Examples of the antireflection treatment (anti-reflection treatment) include ARS and ARC manufactured by Nitto Denko Corporation. Examples of the commercially available film subjected to the hard coat treatment and the antistatic treatment include “KC8UX-HA” manufactured by Konica Minolta Opto Co., Ltd. Examples of the commercially available surface treatment layer that has been subjected to the antireflection treatment include ReaLook series manufactured by NOF Corporation.

<G. Liquid crystal display>
The liquid crystal display device of the present invention includes the liquid crystal panel. FIG. 4 is a schematic cross-sectional view of a liquid crystal display device according to a preferred embodiment of the present invention. It should be noted that, for the sake of easy understanding, the ratio of the vertical, horizontal, and thickness of each component shown in FIG. 4 is different from the actual one. The liquid crystal display device 200 includes at least a liquid crystal panel 100 and a backlight unit 80 disposed on one side of the liquid crystal panel 100. In the illustrated example, the case where the direct type is adopted as the backlight unit is shown, but this may be a side light type, for example.

  When the direct type is adopted, the backlight unit 80 preferably includes at least a light source 81, a reflection film 82, a diffusion plate 83, a prism sheet 84, and a brightness enhancement film 85. When the sidelight method is adopted, preferably, the backlight unit further includes at least a light guide plate and a light reflector in addition to the above-described configuration. In addition, as long as the optical member illustrated in FIG. 4 exhibits the effects of the present invention, a part of the optical member such as an illumination method of a liquid crystal display device or a drive mode of a liquid crystal cell may be omitted depending on the application, or others. The optical member can be replaced.

  The liquid crystal display device may be a transmissive type that irradiates light from the back side of the liquid crystal panel to view the screen, or a reflective type that irradiates light from the viewing side of the liquid crystal panel to view the screen. good. Alternatively, the liquid crystal display device may be a transflective type having both transmissive and reflective properties.

  The liquid crystal display device of the present invention is used for any appropriate application. Applications include, for example, OA equipment such as personal computer monitors, notebook computers, and copiers, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, microwave ovens, etc. Home appliances, back monitors, car navigation system monitors, car audio and other in-vehicle equipment, exhibition equipment such as commercial store information monitors, security equipment such as surveillance monitors, nursing care monitors, medical monitors, etc. Nursing care / medical equipment.

  Preferably, the use of the liquid crystal display device of the present invention is a television. The screen size of the television is preferably a wide 17 type (373 mm × 224 mm) or more, more preferably a wide 23 type (499 mm × 300 mm) or more, and particularly preferably a wide 32 type (687 mm × 412 mm) or more. .

The present invention will be further described using the above examples and comparative examples. In addition, this invention is not limited only to these Examples. In addition, each analysis method used in the Example is as follows.
(1) Measurement of single transmittance of polarizer:
Using a spectrophotometer [product name “DOT-3” manufactured by Murakami Color Research Laboratory Co., Ltd.], the Y value after correcting the visibility was measured with a two-degree field of view (C light source) of JLS Z 8701-1982. did.
(2) Measurement of polarization degree of polarizer:
Using a spectrophotometer [product name “DOT-3” manufactured by Murakami Color Research Laboratory Co., Ltd.], the parallel transmittance (H ₀ ) and orthogonal transmittance (H ₉₀ ) of the polarizer are measured. Degree (%) = {(H ₀ −H ₉₀ ) / (H ₀ + H ₉₀ )} ^1/2 × 100. The parallel transmittance (H ₀ ) is a value of the transmittance of a parallel laminated polarizer prepared by superposing two polarizers of the same type so that their absorption axes are parallel to each other. The orthogonal transmittance (H ₉₀ ) is a value of the transmittance of an orthogonal laminated polarizer produced by superposing two polarizers of the same type so that their absorption axes are orthogonal to each other. In addition, these transmittance | permeability is Y value which performed visibility correction | amendment by the 2 degree visual field (C light source) of JlS Z 8701-1982.
(3) Measuring method of phase difference value (Re [λ], Rth [λ]), Nz coefficient, T [590]:
Measurement was performed at 23 ° C. using a trade name “KOBRA21-ADH” manufactured by Oji Scientific Instruments. In addition, the value measured using the Abbe refractometer [Atago Co., Ltd. product name "DR-M4"] was used for the average refractive index.
(4) Measuring method of thickness:
When the thickness was less than 10 μm, measurement was performed using a thin film spectrophotometer [manufactured by Otsuka Electronics Co., Ltd., “instant multiphotometry system MCPD-2000”]. When the thickness was 10 μm or more, measurement was performed using an Anritsu digital micrometer “KC-351C type”.
(5) Method for measuring molecular weight of polyimide resin:
Polyethylene oxide was calculated as a standard sample by a gel permeation chromatograph (GPC) method. The equipment, instruments and measurement conditions are as follows.
Sample: A sample was dissolved in an eluent to prepare a 0.1% by weight solution.
-Pretreatment: After standing for 8 hours, it was filtered through a 0.45 µm membrane filter.
・ Analyzer: “HLC-8020GPC” manufactured by Tosoh Corporation
・ Column: Tosoh GMH _XL + GMH _XL + G2500H _XL
Column size: 7.8 mmφ x 30 cm each (total 90 cm)
Eluent: Dimethylformamide (added with 10 mM lithium bromide and 10 mM phosphoric acid to make up to 1 L dimethylformamide solution)
-Flow rate: 0.8 ml / min.
・ Detector: RI (differential refractometer)
-Column temperature: 40 ° C
・ Injection volume: 100 μl
(6) Method for measuring molecular weight of norbornene resin:
Polystyrene was calculated as a standard sample by the gel permeation chromatograph (GPC) method. Specifically, it measured with the following apparatuses, instruments, and measurement conditions. The sample is
Measurement sample: The sample was dissolved in tetrahydrane to give a 0.1% by weight solution, allowed to stand overnight, and then filtered using a 0.45 μm membrane filter.
・ Analyzer: “HLC-8120GPC” manufactured by TOSOH
Column: TSKgel Super HM-H / H4000 / H3000 / H2000
Column size: 6.0 mmI. D. × 150mm
-Eluent: Tetrahydrofuran-Flow rate: 0.6 ml / min.
・ Detector: RI (differential refractometer)
-Column temperature: 40 ° C
・ Injection volume: 20 μl
(7) Measuring method of glass transition temperature:
Using a differential scanning calorimeter [Seiko Co., Ltd. product name “DSC-6200”], it was determined by a method according to JIS K 7121 (1987) (measurement method of plastic transition temperature). Specifically, a 3 mg powder sample was heated twice (heating rate: 10 ° C./min) in a nitrogen atmosphere (gas flow rate: 80 ml / min) and measured twice, and the second data was adopted. The calorimeter corrected the temperature using a standard material (indium).
(8) Measuring method of absolute value (C [590]) of photoelastic coefficient:
Using a spectroscopic ellipsometer [product name “M-220” manufactured by JASCO Corporation], the sample (size 2 cm × 10 cm) is sandwiched at both ends and stress (5 to 15 N) is applied to the phase difference at the center of the sample. The value (23 ° C./wavelength 590 nm) was measured and calculated from the slope of the function of stress and retardation value.
(9) Measuring method of light leakage amount in oblique direction of liquid crystal display device:
After 30 minutes have passed since the backlight was turned on in a dark room at 23 ° C., a black image was displayed using the product name “EZ Contrast 160D” manufactured by ELDIM. The Y value of the XYZ display system in the range from 80 to 80 ° was measured. The long side of the liquid crystal panel was set to an azimuth angle of 0 °, and the normal direction was set to a polar angle of 0 °.
(10) Measuring method of color shift amount (ΔE) of liquid crystal display device:
After 30 minutes have passed since the backlight was turned on in a dark room at 23 ° C., using an ELDIM product name “EZ Contrast 160D”, the azimuth angle of the screen displaying the black image is 30 °, and the polar angle is 0 ° to 80 °. Luminance L ^* and color coordinates a ^* and b ^* defined in the CIE 1976 L ^* a ^* b ^* color space are measured. The oblique color shift amount (ΔE) was calculated from the formula: {(L ^* ) ² + (a ^* ) ² + (b ^* ) ² } ^1/2 .

Preparation of polarizer [Reference Example 1]
A commercially available polarizing plate [trade name “NPF SIG1423DU” manufactured by Nitto Denko Corporation] was used as the polarizing plate A as it was. The polarizing plate A includes a polarizer and protective layers disposed on both sides of the polarizer. The single transmittance of the polarizer was 43%, and the degree of polarization was 99%. The two protective layers of the polarizing plate A are both substantially isotropic, Re [590] = 0.5 nm, and Rth [590] is 1 nm.

[Reference Example 2]
A commercially available polarizing plate [trade name “NPF SEG1423DU” manufactured by Nitto Denko Corporation] was used as the polarizing plate B as it was. The polarizing plate B includes a polarizer and protective layers disposed on both sides of the polarizer. The single transmittance of the polarizer was 43%, and the degree of polarization was 99%. The two protective layers of the polarizing plate B have a refractive index ellipsoid of nx = ny> nz, Re [590] = 0.5 nm, and Rth [590] is 60 nm.

Preparation of liquid crystal cell [Reference Example 3]
Take out the liquid crystal panel from a commercially available liquid crystal display device including a VA mode liquid crystal cell [Sony's 40-inch liquid crystal television product name “BRAVIA KDL-40X1000”] and remove optical films such as polarizing plates placed above and below the liquid crystal cell. All removed. The front and back of the glass plate of the obtained liquid crystal cell were washed, and liquid crystal cell A was obtained.

Synthesis of olefin / maleimide resin [Reference Example 4]
In a 1 liter autoclave, 400 ml of toluene as a polymerization solvent, 0.001 mol of perbutyl neodecanoate as a polymerization initiator, 0.42 mol of N- (2-methylphenyl) maleimide, 4.05 mol of isobutene were charged. The mixture was reacted at 5 ° C. for 5 hours to obtain an N- (2-methylphenyl) maleimide-isobutene alternating copolymer. The obtained resin had a weight average molecular weight (standard polystyrene conversion value) of 160,000.

Synthesis of polyimide resin [Reference Example 5]
2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropanoic acid dianhydride in a reaction vessel (500 mL) equipped with a mechanical stirrer, Dean-Stark device, nitrogen inlet tube, thermometer and condenser tube [Clariant Japan Co., Ltd.] 17.77 g (40 mmol) and 2,2-bis (trifluoromethyl) -4,4′-diaminobiphenyl [Wakayama Seika Kogyo Co., Ltd.] 12.81 g (40 mmol) added. Subsequently, a solution in which 2.58 g (20 mmol) of isoquinoline was dissolved in 275.21 g of m-cresol was added, and the mixture was stirred at 23 ° C. for 1 hour (600 rpm) to obtain a uniform solution. Next, the reaction vessel was heated using an oil bath so that the temperature in the reaction vessel became 180 ± 3 ° C., and stirred for 5 hours while maintaining the temperature to obtain a yellow solution. After further stirring for 3 hours, the heating and stirring were stopped, and the mixture was allowed to cool to room temperature.

  Acetone was added to the yellow solution in the reaction vessel to completely dissolve the gel to prepare a diluted solution (7% by weight). When this diluted solution was gradually added to 2 L of isopropyl alcohol while stirring, a white powder was precipitated. This powder was collected by filtration and poured into 1.5 L of isopropyl alcohol for washing. Further, the same operation was repeated once again for washing, and then the powder was collected again by filtration. This was dried for 48 hours in an air circulation type constant temperature oven at 60 ° C. and then dried at 150 ° C. for 7 hours to obtain a polyimide powder of the following structural formula (IV) (yield 85%). The polyimide had a polymerization average molecular weight (Mw) of 124,000 and an imidation ratio of 99.9%.

Preparation of laminated film (A) [Reference Example 6]
The N- (2-methylphenyl) maleimide-isobutene alternating copolymer prepared in Reference Example 4 was dissolved in methyl ethyl ketone to prepare a solution having a solid content concentration of 33% by weight. This solution was applied to a surface of a polymer film containing a 71 μm-thick norbornene resin [JSR Co., Ltd., trade name “ARTON F5023”] using a Baker type applicator (manufactured by Tester Sangyo Co., Ltd.). (Gap 100 μm), dried in an air circulation drying oven at 80 ° C. for 10 minutes, further dried at 120 ° C. for 20 minutes and further in vacuum at 70 ° C. for 3 hours, and laminated with a thickness of 110 μm The body (A-1) was obtained. Next, this laminate (A-1) was stretched 2.0 times at 130 ° C. by a free end longitudinal uniaxial stretching method using a simultaneous biaxial stretching machine (manufactured by Shibayama Kagaku Kikai), and a laminated film (A-1) was produced. Table 1 shows the characteristics of the laminated film (A-1). The norbornene-based resin layer of the laminated film (A-1) corresponds to the retardation film (a ₁ ) in the present invention, and the olefin / maleimide-based resin layer corresponds to the retardation film (a ₂ ) in the present invention. Equivalent to. The slow axis direction of the norbornene resin layer of the laminated film (A-1) is substantially orthogonal to the slow axis direction of the olefin / maleimide resin layer.

[Reference Example 7]
A solution containing the same N- (2-methylphenyl) maleimide-isobutene alternating copolymer as in Reference Example 6 and a polymer film containing a norbornene-based resin [JSR Co., Ltd., trade name “ARTON F5023”] having a thickness of 143 μm On one surface, a 12-mil (gap 300 μm) coating was performed using a baker-type applicator and dried under the same method and conditions as in Reference Example 6 to obtain a laminate (A-2) having a thickness of 273 μm. . Next, this laminate (A-2) was stretched in the same manner as in Reference Example 6 to produce a laminate film (A-2). Table 1 shows the characteristics of the laminated film (A-2). The slow axis direction of the norbornene-based resin layer of the laminated film (A-2) is substantially perpendicular to the slow axis direction of the N- (2-methylphenyl) maleimide-isobutene alternating copolymer layer. is there.

[Reference Example 8]
A solution containing an N- (2-methylphenyl) maleimide-isobutene alternating copolymer similar to that in Reference Example 6 was added to a polymer film containing a norbornene-based resin [JSR Corporation, trade name “ARTON F5023”] having a thickness of 214 μm. One surface was coated with 10 mil (gap 250 μm) using a Baker type applicator, dried in an air circulation drying oven at 80 ° C. for 10 minutes, and further dried at 120 ° C. for 20 minutes. Subsequently, after applying the above solution to the other surface of the polymer film at 10 mil (gap 250 μm) using a baker type applicator, and drying in an air circulation drying oven at 80 ° C. for 10 minutes. Further, it was dried at 120 ° C. for 20 minutes and further under a vacuum of 70 ° C. for 3 hours to obtain a laminate (A-3) having a thickness of 370 μm. Next, this laminate (A-3) was stretched in the same manner as in Reference Example 6 to produce a laminate film (A-3). Table 1 shows the characteristics of the laminated film (A-3). The slow axis direction of the norbornene resin layer of the laminated film (A-3) is substantially orthogonal to the slow axis direction of the olefin / maleimide resin layer.

Production of retardation film (B) [Reference Example 9]
The polyimide powder produced in Reference Example 5 was dissolved in methyl isobutyl ketone to prepare a 15% by weight polyimide solution. This solution is uniformly cast in the form of a sheet with a comma coater on the surface of a polyethylene terephthalate film [trade name “Lumirror S27-E” manufactured by Toray Industries, Inc.] having a thickness of 75 μm. In the oven (error ± 1 ° C.), the solvent was evaporated while gradually raising the temperature from low temperature to 80 ° C. for 2 minutes, 135 ° C. for 5 minutes, and 150 ° C. for 10 minutes. The polyethylene terephthalate film was peeled off to produce a 3.5 μm thick polyimide layer (retardation film (B)). The retardation film (B) has a refractive index ellipsoid showing a relationship of nx = ny> nz, T _B [590] = 91%, Re _B [590] = 1 nm, Rth _B [590] = 140 nm, wavelength The dispersion value (D _B ) = 0.78.

Production of liquid crystal panel and liquid crystal display device [Example]
On the surface of the liquid crystal cell A prepared in Reference Example 3 on the viewing side, the laminated film (A-3) obtained in Reference Example 8 is acrylic adhesive so that the olefin / maleimide resin layer is on the liquid crystal cell side. Through the agent layer (20 μm), the slow axis direction of the laminated film (A-3) was stuck so as to be substantially orthogonal to the long side direction of the liquid crystal cell A. Next, the polarizing plate A obtained in Reference Example 1 is absorbed on the surface on the viewing side of the laminated film ((A-3)) via the acrylic pressure-sensitive adhesive layer (20 μm). Adhering was performed so that the axial direction was substantially parallel to the long side direction of the liquid crystal cell A. At this time, the absorption axis direction of the polarizing plate A and the slow axis direction of the laminated film (A-3) are substantially orthogonal.

Subsequently, the retardation film (B) obtained in Reference Example 9 was attached to the backlight side surface of the liquid crystal cell A via an acrylic pressure-sensitive adhesive layer (20 μm). Next, the polarizing plate B obtained in Reference Example 2 is applied to the backlight side surface of the retardation film (B) via the acrylic pressure-sensitive adhesive layer (20 μm) in the absorption axis direction of the polarizing plate B. However, it was stuck so as to be substantially orthogonal to the long side direction of the liquid crystal cell A. At this time, the absorption axis direction of the polarizing plate A and the absorption axis direction of the polarizing plate B are substantially orthogonal. 5 is a wavelength dispersion characteristic of retardation of the laminated film (A-3 and retardation film (B) used in the example. The vertical axis in FIG. 5 is relative to the plot of the laminated film (A-3). Re [λ] / Re [590] and R40 [λ] / R40 [590] for the plot of the retardation film (B) The liquid crystal panel A has ΔD (D _B −D _A ) = 0.28.

This liquid crystal panel A was combined with the backlight unit of the original liquid crystal display device to produce a liquid crystal display device A.
When the liquid crystal display device A displays a black image,
Average value of Y values of azimuth angle 60 °, polar angle 0 ° -80 ° = 0.85
Maximum Y value of azimuth angle 60 °, polar angle 0 ° -80 ° = 1.44
Difference between maximum value and minimum value of Y value at azimuth angle 60 ° and polar angle 0 ° -80 ° = 1.08
Average value of ΔE at azimuth angle 30 ° and polar angle 0 ° -80 ° = 8.5
Maximum value of ΔE at an azimuth angle of 30 ° and a polar angle of 0 ° to 80 ° = 13.9
Difference between maximum value and minimum value of ΔE at azimuth angle 30 ° and polar angle 0 ° -80 ° = 10.4
Met.

[Comparative example]
The liquid crystal panel X and the liquid crystal display device X were prepared in the same manner as in Example 1 except that the retardation film (X) was used instead of the laminated film (A-2) disposed on the viewing side of the liquid crystal cell. Produced. The retardation film (X) is a stretched film of a polymer film containing a norbornene resin [JSR Co., Ltd., trade name “ARTON F5023”], and the refractive index ellipsoid shows a relationship of nx> ny = nz. , Re [590] is 140 nm.
When the liquid crystal display device X displays a black image,
Average value of Y values of azimuth angle 60 °, polar angle 0 ° -80 ° = 0.97
Maximum Y value of azimuth angle 60 °, polar angle 0 ° -80 ° = 1.85
Difference between maximum value and minimum value of Y value at azimuth angle 60 ° and polar angle 0 ° -80 ° = 1.53
Average value of ΔE of azimuth angle 30 ° and polar angle 0 ° -80 ° = 9.0
Maximum value of ΔE at an azimuth angle of 30 ° and a polar angle of 0 ° to 80 ° = 15.3
Difference between maximum value and minimum value of ΔE of azimuth angle 30 ° and polar angle 0 ° -80 ° = 11.9
Met.

[Evaluation]
FIG. 6 shows changes in light leakage (Y value) at the azimuth angle of 60 ° and the polar angles of 0 ° to 80 ° of the screen displaying the black image in the liquid crystal display devices of the example and the comparative example. FIG. 7 shows changes in color shift (ΔE) in the azimuth angle 30 ° and polar angles 0 ° to 80 ° of the screen displaying the black image in the liquid crystal display devices of the example and the comparative example. As is apparent from FIGS. 6 and 7, the liquid crystal display device of the example has a smaller amount of change depending on the polar angle of the Y value and ΔE than the liquid crystal display device of the comparative example, and light leakage in an oblique direction. It can be seen that the color shift is extremely small.

  As described above, since the liquid crystal panel of the present invention exhibits excellent display characteristics, it can be suitably used for liquid crystal televisions, mobile phones and the like.

It is a schematic sectional drawing of the liquid crystal panel by the 1st Embodiment of this invention. It is a schematic sectional drawing of the liquid crystal panel by the 2nd Embodiment of this invention. It is a schematic diagram which shows the concept of the typical manufacturing process of the polarizer used for this invention. 1 is a schematic cross-sectional view of a liquid crystal display device according to a preferred embodiment of the present invention. It is the wavelength dispersion characteristic of the retardation of the laminated film (A-3 and retardation film (B) used in the Example. It is a change of the amount of light leakage (Y value) in the liquid crystal display device of an Example and a comparative example in the azimuth | direction angle of 60 degrees of the screen which displayed the black image, and the polar angles of 0 degrees-80 degrees. This is a change in color shift (ΔE) at an azimuth angle of 30 ° and a polar angle of 0 ° to 80 ° of a screen displaying a black image in the liquid crystal display devices of Examples and Comparative Examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 21 1st polarizer 22 2nd polarizer 31 Laminated | multilayer film (A)
32 retardation film (B)
DESCRIPTION OF SYMBOLS 80 Backlight unit 81 Light source 82 Reflective film 83 Diffusion plate 84 Prism sheet 85 Brightness improvement film 100 Liquid crystal panel 200 Liquid crystal display device 301 Polymer film which has a polyvinyl alcohol resin as a main component 310 Aqueous solution bath 311, 312, 321 322, 331, 332 Roll 320 Aqueous solution bath containing boric acid and potassium iodide 330 Aqueous solution bath containing potassium iodide 340 Drying means 350 Polarizer 360 Winding unit

Claims (15)

A liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, the liquid crystal cell and the first polarizer At least a laminated film (A) disposed between and a retardation film (B) disposed between the laminated film (A) and the second polarizer,
The laminated film (A) includes a retardation film (a ₁ ) in which the refractive index ellipsoid has a relationship of nx> ny ≧ nz, and a retardation film (a) in which the refractive index ellipsoid has a relationship of nz ≧ nx> ny. ₂ ) and
The retardation film (B) is a liquid crystal panel in which a refractive index ellipsoid shows a relationship of nx = ny> nz.   The liquid crystal panel according to claim 1, wherein the liquid crystal cell includes liquid crystal molecules aligned in a homeotropic alignment.   The liquid crystal panel according to claim 1 or 2, wherein a slow axis direction of the laminated film (A) is substantially perpendicular to an absorption axis direction of the first polarizer.   The in-plane retardation value (Re [590]) at a wavelength of 590 nm of the laminated film (A) is larger than the in-plane retardation value (Re [480]) at a wavelength of 480 nm. Liquid crystal panel according to crab. The retardation wavelength dispersion value of the film (B) and (D _B), the difference between the laminated wavelength dispersion value of the film _{(A) (D A) (} D B -D A) is 0.05 or more, wherein Item 5. The liquid crystal panel according to any one of items 1 to 4:
Here, the chromatic dispersion value (D _A ) is a value calculated from the equation; Re [480] / Re [590], and Re [480] and Re [590] are in-plane at wavelengths of 480 nm and 590 nm, respectively. The chromatic dispersion value (D _B ) is a value calculated from the equation; R40 [480] / R40 [590], and R40 [480] and R40 [590] have wavelengths of 480 nm and 480 nm, respectively. It is a phase difference value measured by tilting by 40 degrees from the normal direction at 590 nm. 6. The liquid crystal panel according to claim 1, wherein a slow axis direction of the retardation film (a ₁ ) is substantially perpendicular to a slow axis direction of the retardation film (a ₂ ). The liquid crystal panel according to claim 1, wherein the retardation film (a ₁ ) is disposed between the first polarizer and the retardation film (a ₂ ). The in-plane retardation value (Re ₁ [590]) at a wavelength of 590 nm of the retardation film (a ₁ ) is larger than Re ₂ [590] of the retardation film (a ₂ ). A liquid crystal panel according to any one of the above. The in-plane retardation value at a wavelength of 590nm of in-plane retardation value at a wavelength of 590nm (Re ₁ [590]) and the retardation film (a ₂₎ of the retardation film _{(a 1) (Re 2 [} 590] The difference (Re ₁ [590] −Re ₂ [590]) with respect to ()) is 100 nm to 200 nm, and the liquid crystal panel according to claim 1. The liquid crystal panel according to claim 1, wherein the retardation film (a ₁ ) contains a norbornene resin. The liquid crystal panel according to claim 1, wherein the retardation film (a ₂ ) contains a thermoplastic resin exhibiting negative birefringence.   The thermoplastic resin exhibiting negative birefringence is styrene / maleic anhydride copolymer, styrene / (meth) acrylonitrile copolymer, styrene / (meth) acrylate copolymer, styrene / maleimide copolymer, vinyl. The liquid crystal panel according to claim 11, which is an ester / maleimide copolymer or an olefin / maleimide copolymer. The liquid crystal panel according to any one of claims 1 to 12, wherein an in-plane birefringence (Δn _xy [590]) of the retardation film (a ₂ ) at a wavelength of 590 nm is 0.002 or more.   The liquid crystal panel according to claim 1, wherein the retardation film (B) contains a polyimide resin. A liquid crystal display device comprising the liquid crystal panel according to claim 1.