JP4882223B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device. More specifically, the present invention prevents a decrease in contrast when the screen is viewed from an oblique direction without deteriorating image characteristics from the front direction, and is a liquid crystal display having a uniform and high contrast when viewed from any direction. Relates to the device.

Liquid crystal display devices have features such as high image quality, thinness, light weight, and low power consumption, and are widely used in televisions, personal computers, car navigators, and the like. In a liquid crystal display device, two polarizers are arranged above and below a liquid crystal cell so that transmission axes are orthogonal to each other, and a voltage is applied to the liquid crystal cell to change the orientation of liquid crystal molecules and display an image on a screen. . In a twisted nematic mode liquid crystal display device, liquid crystal molecules are often in a vertical alignment state when a voltage is applied, resulting in a black display. In an in-plane switching mode liquid crystal display device, liquid crystal molecules are aligned in a certain direction when no voltage is applied, and the alignment direction is rotated by 45 ° when a voltage is applied, resulting in white display.
In the liquid crystal display device in which the transmission axes of the two polarizers are arranged so as to be orthogonal to the vertical direction and the horizontal direction, sufficient contrast is obtained when the screen is viewed from the vertical and horizontal directions. However, when the screen is viewed obliquely from a direction deviating from the top, bottom, left, and right, the transmitted light causes birefringence and the light leaks, so that sufficient black cannot be obtained and the contrast is lowered. For this reason, an attempt has been made to add an optical compensation means to the liquid crystal display device to prevent a reduction in the contrast of the screen.
For example, in an active matrix liquid crystal display device in an in-plane switching mode, as a liquid crystal display device that prevents a decrease in contrast when the screen is viewed obliquely from a direction with an azimuth angle of 45 ° without reducing the characteristics in the front direction. The first polarizing plate, the optical compensation film, the first substrate, the liquid crystal layer, the second substrate, and the second polarizing plate are arranged in this order, and one of the polarizing plates is parallel to the liquid crystal slow axis when the liquid crystal layer displays black. Proposed is a liquid crystal display device in which an angle formed by a film slow axis of an optical compensation film and a transmission axis of one of polarizing plates is 0 to 2 ° or 88 to 90 °. (Patent Document 1).
As a liquid crystal display device with a wide viewing angle using a polarizing plate that compensates for the deviation of the transmission axis due to the azimuth, a sealing film having a birefringence with a retardation of 190 to 320 nm is adhered to a polarizer. A liquid crystal display device has been proposed in which a polarizing plate in which the slow axis of the sealing film is arranged in parallel to the absorption axis of a polarizer is arranged on at least one side of a liquid crystal cell (Patent Document 2). .
In addition, a polarizing plate capable of achieving a wide viewing angle liquid crystal display device by preventing light leakage based on a change in the axis of the polarizer caused by a change in viewing angle between polarizers arranged in crossed Nicols in a wide visible light range. As an example, two layers of retardation films having an in-plane retardation of 190 to 320 nm are bonded to at least one surface of the polarizer so that the slow axis of each retardation film is parallel to the absorption axis of the polarizer. And when the in-plane refractive index is nx, ny, and the refractive index in the thickness direction is nz, the two-layer retardation film has an Nz = (nx−nz) / (nx−ny) of 0.65. There has been proposed a polarizing plate composed of a combination of those of ˜0.85 and those of 0.15 to 0.35 (Patent Document 3).
At least one optical axis or light axis within 45 ° around the normal direction of the film as a liquid crystal display device which does not lose color due to a change in angle or disappearance of the display content even when the display is viewed obliquely Or n _TH- (n _MD + n _TD ) / 2 where n _{TH is} the refractive index in the normal direction of the film, n _{MD is} the refractive index in the longitudinal direction, and n _TD is the refractive index in the width direction. A liquid crystal display device in which a film that is> 0 and a uniaxially stretched film having a positive intrinsic birefringence value is inserted between a liquid crystal cell and a polarizing plate has been proposed (Patent Document 4).
Furthermore, as a liquid crystal display device that does not lose color due to a change in angle or disappearance of screen display content even when viewed from an oblique direction, a liquid crystal element sandwiching nematic liquid crystal is a uniaxially stretched film having a positive intrinsic birefringence value. A liquid crystal display device sandwiched between uniaxially stretched films having a negative intrinsic birefringence value has been proposed (Patent Document 5).
In addition to the phase difference due to the birefringence of the liquid crystal and the change due to its viewing angle, as a phase difference plate having abundant phase difference characteristics capable of dealing with the wavelength dependence of these characteristics, the in-plane main refractive index is nx, ny, where the refractive index in the thickness direction is nz, nx>ny> nz, nx = nz> ny, nx = ny> nz, etc. used in a combination of two or more retardation films exhibiting refractive index characteristics A phase difference plate has been proposed (Patent Document 6).
However, these means are still insufficient to obtain a liquid crystal display device having a uniform and high contrast when viewed from any direction, and further improvement is required.
JP 11-305217 A (page 2-3) JP-A-4-305602 (2nd page) JP 2002-148433 A (2nd page) JP-A-2-256603 (page 1-2) JP-A-3-206422 (page 1-2) JP 2000-227520 A (page 2)

  The present invention prevents a decrease in contrast when viewing the screen from an oblique direction without deteriorating the image characteristics from the front direction compared to the conventional one, has a wide viewing angle, and is homogeneous from any direction. The object of the present invention is to provide a liquid crystal display device capable of obtaining a high contrast.

As a result of intensive studies to solve the above problems, the present inventors have obtained an optical anisotropic layer having a negative intrinsic birefringence value and an optical anisotropic layer having a positive intrinsic birefringence value. Based on this finding, it was found that a liquid crystal display device having a wide viewing angle and a high contrast can be obtained by disposing the liquid crystal cell and the polarizer in a specific positional relationship to prevent a decrease in contrast. The present invention has been completed.
That is, the present invention
(1) An in-plane switching mode having at least an optical anisotropic body (A), an optical anisotropic body (B), and a liquid crystal cell between a pair of polarizers in which the respective transmission axes are substantially perpendicular to each other . A liquid crystal display device comprising a liquid crystal cell, an optical anisotropic body (B), and an optical anisotropic body (A) in this order, wherein the optical anisotropic body (A) is made of a material layer having a negative intrinsic birefringence value. The optical anisotropic body (B) is made of a material layer having a positive intrinsic birefringence value, and the slow axis in the plane of the optical anisotropic body (A) and the plane of the optical anisotropic body (B) There retarded and the phase axis of the positional relationship between the Ryakutaira row, the slow axis voltage slow axis positional relationship substantially perpendicular in the plane of the liquid crystal cell of the non-applied state in the plane of the optically anisotropic member (a) There, optically anisotropic transmission axis positional relationship near substantially parallel or substantially perpendicular polarizers towards the in-plane slow axis is disposed in the vicinity of (a) is, optically anisotropic member (a) The in-plane retardation is from 60 nm to 110 nm, the thickness direction retardation of the optical anisotropic body (A) is from −70 nm to −25 nm, and the in-plane retardation of the optical anisotropic body (B) is from 70 nm to 120 nm. The optical anisotropic body (B) has a thickness direction retardation of 25 nm or more and 65 nm or less, and each surface of the optical anisotropic body (A) and the optical anisotropic body (B) measured with light having a wavelength of 550 nm. a slow axis direction of the refractive index nx _a and nx _B of the inner, slow-phase axis and plane direction of the refractive index ny _a and ny _B orthogonal, the refractive index in the thickness direction and nz _a and nz _B when the absolute value of the difference between nx _a and nz _a is 0.003 or less, a liquid crystal display device in which the absolute value of the difference between ny _B and nz _B is characterized der Rukoto 0.003,
(2) In-plane switching mode having at least an optical anisotropic body (A), an optical anisotropic body (B), and a liquid crystal cell between a pair of polarizers in which the respective transmission axes are substantially perpendicular to each other. A liquid crystal display device comprising a liquid crystal cell, an optical anisotropic body (A), and an optical anisotropic body (B) in this order, wherein the optical anisotropic body (A) is made of a material layer having a negative intrinsic birefringence value. The optical anisotropic body (B) is made of a material layer having a positive intrinsic birefringence value, and the slow axis in the plane of the optical anisotropic body (A) and the plane of the optical anisotropic body (B) The slow axis is in a substantially parallel positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is in a substantially parallel positional relationship with the slow axis in the surface of the liquid crystal cell in the state where no voltage is applied. The slow axis in the plane of the optical anisotropic body (A) is substantially parallel or substantially perpendicular to the transmission axis of the polarizer disposed in the vicinity, and the plane of the optical anisotropic body (A) Letter letter Is 70 nm or more and 120 nm or less, the thickness direction retardation of the optical anisotropic body (A) is −65 nm or more and −25 nm or less, and the in-plane retardation of the optical anisotropic body (B) is 50 nm or more and 110 nm or less. The retardation in the thickness direction of the optical anisotropic body (B) is 25 nm or more and 70 nm or less, and the in-plane retardation of the optical anisotropic body (A) and the optical anisotropic body (B) measured with light having a wavelength of 550 nm. When the refractive index in the phase axis direction is nx _A and nx _B , the refractive index in the direction orthogonal to the slow axis in the plane is ny _A and ny _B , and the refractive index in the thickness direction is nz _A and nz _B , an in-plane switching mode liquid crystal display device, wherein an absolute value of a difference between nx _A and nz _A is 0.003 or less, and an absolute value of a difference between ny _B and nz _B is 0.003 or less;
(3) The liquid crystal display device according to (1) or (2), wherein nz _A > ny _A and nx _B > nz _B are satisfied,
( 4 ) The liquid crystal display device according to any one of (1) to ( 3 ), wherein the optical anisotropic body (A) is formed by laminating a transparent resin layer on at least one side of the layer ;
( 5 ) The liquid crystal according to any one of (1) to ( 4 ), wherein the content of residual volatile components in the optical anisotropic body (A) and the optical anisotropic body (B) is 0.1% by weight or less. Display device ,
Is to provide.
Furthermore, as a preferred embodiment of the present invention,
( 6 ) The liquid crystal display device according to any one of (1) to ( 5 ), wherein the material having a negative intrinsic birefringence value is a vinyl aromatic polymer.
( 7 ) The liquid crystal display device according to ( 6 ), wherein the vinyl aromatic polymer is polystyrene or a copolymer of styrene and maleic anhydride, and
( 8 ) The liquid crystal display device according to any one of (1) to ( 7 ), wherein the material having a positive intrinsic birefringence value is a polymer having an alicyclic structure.
Can be mentioned.

  Since the liquid crystal display device of the present invention has a wide viewing angle and is homogeneous and has high contrast when viewed from any direction, it can be suitably used as a large-screen flat panel display.

The liquid crystal display device of the present invention includes at least an optical anisotropic body (A), an optical anisotropic body (B), and a liquid crystal cell between a pair of polarizers whose transmission axes are in a substantially vertical positional relationship. In the liquid crystal display device, the optical anisotropic body (A) is made of a material layer having a negative intrinsic birefringence value, and the optical anisotropic body (B) is made of a material layer having a positive intrinsic birefringence value. , in the position relationship between the slow axis and the Ryakutaira line in the plane of the slow axis and the optically anisotropic member in the plane of the optically anisotropic member (a) (B), the surface of the optically anisotropic member (a) This is a liquid crystal display device in which the slow axis is substantially parallel or substantially perpendicular to the transmission axis of the polarizer disposed in the vicinity.
In the present invention, the angle formed by two axes refers to an angle formed by two surfaces, each having a normal line. However, the angle formed is the smaller one. In the present invention, that the two axes are in a substantially parallel positional relationship means that the angle formed by the two axes is 0 to 3 °. In the present invention, the fact that the two axes are in a substantially vertical positional relationship means that the angle formed by the two axes is 87 to 90 °.

The intrinsic birefringence value Δn ⁰ is a value calculated by the equation [1].
Δn ⁰ = (2π / 9) (Nd / M) {(n _a +2) ² / n _a } (α ₁ −α ₂ ) (1)
Where π is the circumference, N is the Avogadro number, d is the density, M is the molecular weight, n _a is the average refractive index, α ₁ is the polarizability of the polymer in the direction of the molecular chain axis, and α ₂ is the molecular chain of the polymer. The polarizability in the direction perpendicular to the axis.
Examples of the material having a negative intrinsic birefringence value include vinyl aromatic polymers. Examples of the vinyl aromatic polymer include polystyrene, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, p-aminostyrene, and p-carboxy. Vinyl aromatic monomers such as styrene and p-phenylstyrene, ethylene, propylene, butadiene, isoprene, (meth) acrylonitrile, α-chloroacrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Copolymers with other monomers such as acrylic acid, maleic anhydride and vinyl acetate. Among these, polystyrene or a copolymer of styrene and maleic anhydride can be suitably used.

Examples of materials having a positive intrinsic birefringence value include polymers having an alicyclic structure, polycarbonate, polyarylate, polyethylene terephthalate, polysulfone, polyethersulfone, polyphenylene sulfide, polyimide, polyamideimide, polyethylene, polypropylene, poly Examples include vinyl chloride. Among these, a polymer having an alicyclic structure can be particularly preferably used.
Examples of the polymer having an alicyclic structure include a polymer having an alicyclic structure in the main chain or side chain. Among these, a polymer having an alicyclic structure in the main chain can be suitably used. The alicyclic structure is preferably a saturated cyclic hydrocarbon structure, and the carbon number thereof is preferably 4 to 30, more preferably 5 to 20, and further preferably 6 to 15. . The ratio of the repeating unit having an alicyclic structure in the polymer having an alicyclic structure is preferably 50% by weight or more, more preferably 70% by weight or more, and 90% by weight or more. Is more preferable.
Examples of the polymer having an alicyclic structure include, for example, a ring-opening polymer or a ring-opening copolymer of a norbornene monomer or a hydrogenated product thereof, an addition polymer or an addition copolymer of a norbornene monomer. Or a hydrogenated product thereof, a polymer of a monocyclic cycloolefin monomer or a hydrogenated product thereof, a polymer of a cyclic conjugated diene monomer or a hydrogenated product thereof, a vinyl alicyclic hydrocarbon monomer Polymer or copolymer of the polymer or a hydrogenated product thereof, a polymer of a vinyl aromatic hydrocarbon monomer, or a hydrogenated product of an unsaturated bond part containing an aromatic ring of the copolymer. .
In the present invention, a material having a negative intrinsic birefringence value and / or a material having a positive intrinsic birefringence value may include an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a charge as necessary. Inhibitors, dispersants, chlorine scavengers, flame retardants, crystallization nucleating agents, antiblocking agents, antifogging agents, mold release agents, pigments, organic or inorganic fillers, neutralizing agents, lubricants, decomposition agents, metal-free Known additives such as activators, antifouling agents, antibacterial agents and other resins, and thermoplastic elastomers can be added as long as the effects of the invention are not impaired.

In the liquid crystal display device of the present invention, the refractive indexes in the slow axis direction in the planes of the optical anisotropic body (A) and the optical anisotropic body (B) measured with light having a wavelength of 550 nm are nx _A and nx _B , and the slow phase. It is preferable that nz _A > ny _A, where ny _A and ny _B are the refractive indexes in the direction orthogonal to the axis and nz _A and nz _{B in} the thickness direction, and nz _A −ny _A Is more preferably 0.0001 or more, and nz _A -ny _A is more preferably 0.00003 or more. Further, nx _B > nz _B is preferable, nx _B -nz _B is more preferably 0.0001 or more, and nx _B -nz _B is more preferably 0.00003 or more. If nz _A ≦ ny _A or nx _B ≦ nz _B , the contrast may be lower than in a state where no optical anisotropic body is inserted.
In the liquid crystal display device of the present invention, the contrast (CR) is the contrast (CR) = Y _ON / Y _OFF when the brightness at the OFF display of the liquid crystal display device is Y _OFF and the brightness at the ON display is Y _ON. The one represented by The greater the contrast, the better the visibility.
In the present invention, the polar angle means an angle when tilted from the front direction when observing the liquid crystal display screen.
In the present invention, the method for forming the material layer satisfying nz _A > ny _A is not particularly limited. For example, another material is laminated on both sides of the material having a negative intrinsic birefringence value via an adhesive resin layer. The obtained multilayer structure can be formed by coextrusion or the like, and the obtained multilayer structure can be obtained by uniaxial stretching or biaxial stretching, and if necessary, heat treatment. Even if the other material is a material having a positive intrinsic birefringence value, it can be used as a material layer having a negative intrinsic birefringence value as long as the intrinsic birefringence value is negative as a whole multilayer structure. Even if the material has a low intrinsic birefringence value that is difficult to stretch by itself and has a low strength, it can be stretched by forming a multilayer structure in which other materials having a low glass transition temperature are laminated on both sides, _A material layer having negative intrinsic birefringence satisfying nz _A > ny _A can be formed with high productivity without breaking at a temperature at which birefringence is easily exhibited.
In the present invention, the absolute value of the difference between nx _A and nz _A is preferably 0.003 or less, more preferably 0.0005 or less, still more preferably 0.0003 or less, and 0.003 or less. Particularly preferred is 0001 or less. Further, the absolute value of the difference between ny _B and nz _B is preferably 0.003 or less, more preferably 0.0005 or less, further preferably 0.0003 or less, and 0.0001 or less. It is particularly preferred. If the absolute value of the difference between nx _A and nz _A or the difference between ny _B and nz _B exceeds 0.003, the contrast may be lowered as compared with a state where no optical anisotropic body is inserted.

The embodiment comprises a liquid crystal display device of the present invention or reference invention for use optically anisotropic member (A) and an optically anisotropic body (B) the invention or reference invention, there is a preferred arrangement of the 12 type. However, in the following description, six types of arrangements will be described in which the “outgoing side polarizer” side is the viewing side and the “incident side polarizer” side is the backlight installation side. In the six types of arrangements, the arrangement in which the viewing side and the backlight side are switched (that is, the “incident side polarizer” side is the viewing side and the “outgoing side polarizer” side is the backlight installation side) The remaining six types of arrangements show the same viewing angle characteristics as before the viewing side and the backlight side are switched.

  In the liquid crystal display device of the present invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the output side polarizer, and the optical anisotropic body (A) The in-plane slow axis is in a position substantially perpendicular to the in-plane slow axis of the liquid crystal cell in the absence of voltage applied, and the optical anisotropic body (B) is disposed on the liquid crystal cell side. Particularly preferred. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell, and the two polarizers take this positional relationship, so that the minimum contrast value is obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 30 or more. FIG. 1 is an explanatory diagram of one embodiment of the liquid crystal display device of the present invention. In this embodiment, the incident side polarizer 1, the liquid crystal cell 2, the optical anisotropic body (B) 4, the optical anisotropic body (A) 3, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. In the positional relationship, the slow axis in the plane of the optical anisotropic body (A) is perpendicular to the slow axis in the plane of the liquid crystal cell in which no voltage is applied.

In the present invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the output side polarizer, and the in-plane retardation of the optical anisotropic body (A) is obtained. An optical anisotropic body in which the axis is in a position substantially perpendicular to the in-plane slow axis of the liquid crystal cell in the state where no voltage is applied and the optical anisotropic body (B) is disposed on the liquid crystal cell side
(A) In-plane retardation R _e (A) (unit: nm), Thickness direction retardation R _th (A) (unit: nm), In-plane retardation R _e (B) of optical anisotropic body (B) (Unit: nm) and thickness direction retardation R _th (B) (unit: nm) are preferably 10 ≦ R _e (A) ≦ 1000, −500 ≦ R _th (A) ≦ −5, 10 ≦ R _e (B) ≦ 1000, 5 ≦ R _th (B) ≦ 500. More preferable combinations are 10 ≦ R _e (A) ≦ 310, −240 ≦ R _th (A) ≦ −5, 10 ≦ R _e (B) ≦ 300, 5 ≦ R _th (B) ≦ 100; 350 ≦ R _e (A) ≦ 470, −235 ≦ R _th (A) ≦ −175, 450 ≦ R _e (B) ≦ 500, 225 ≦ R _th (B) ≦ 250; 640 ≦ R _e (A) ≦ 700, −350 ≦ R _th (A) ≦ −320, 20 ≦ R _e (B) ≦ 100, 10 ≦ R _th (B) ≦ 50; 730 ≦ R _e (A) ≦ 760, −570 ≦ R _th (A) ≦ −540, 240 ≦ R _e (B) ≦ 280, 120 ≦ R _th (B) ≦ 140. More preferable combinations include 30 ≦ R _e (A) ≦ 150, −90 ≦ R _th (A) ≦ −15, 40 ≦ R _e (B) ≦ 150, and 20 ≦ R _th (B) ≦ 75. . Particularly preferred combinations include 60 ≦ R _e (A) ≦ 110, −70 ≦ R _th (A) ≦ −25, 70 ≦ R _e (B) ≦ 120, and 25 ≦ R _th (B) ≦ 65. . The most preferred combinations include _{70 ≦ R e (A) ≦} 110, -65 ≦ R th (A) ≦ -25,70 ≦ R e (B) ≦ 110,25 ≦ R th (B) ≦ 65 .
In the present invention, the in-plane retardation R _e and the thickness direction retardation R _th are obtained by the following formulas (1) and (2). In the formula, nx, ny, and nz are refractive indexes (−), and d is a thickness (nm).
Equation _{(1): R e = (} nx-ny) × d
Formula (2): R _th = [(nx + ny) / 2−nz] × d

  In the liquid crystal display device of the present invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the output side polarizer, and the optical anisotropic body (A) The in-plane slow axis is in a position substantially parallel to the in-plane slow axis of the liquid crystal cell in the absence of voltage applied, and the optical anisotropic body (A) is disposed on the liquid crystal cell side. Particularly preferred. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell, and the two polarizers take this positional relationship, so that the minimum contrast value is obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 30 or more. FIG. 2 is an explanatory diagram of another embodiment of the liquid crystal display device of the present invention. In this embodiment, the incident side polarizer 1, the liquid crystal cell 2, the optical anisotropic body (A) 3, the optical anisotropic body (B) 4, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. There is a positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied.

In the present invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the output side polarizer, and the in-plane retardation of the optical anisotropic body (A) is obtained. An optical anisotropic body when the optical anisotropic body (A) is disposed on the liquid crystal cell side, and the axis is in a position substantially parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied. In-plane retardation R _e (A) (unit: nm) of A), thickness direction retardation R _th (A) (unit: nm), in-plane retardation R _e (B) of optical anisotropic body (B) ( (Unit: nm) and thickness direction retardation R _th (B) (unit: nm) are preferably 10 ≦ R _e (A) ≦ 1000, −500 ≦ R _th (A) ≦ −5, 10 ≦ R _e (B) ≦ 500, 5 ≦ R _th (B) ≦ 250. A more preferred _{combination, 10 ≦ R e (A)} ≦ 360, -180 ≦ R th (A) ≦ -5,10 ≦ R e (B) ≦ 360,5 ≦ R th (B) ≦ 360; 350 ≦ R _e (A) ≦ 470, −235 ≦ R _th (A) ≦ −175, 450 ≦ R _e (B) ≦ 500, 225 ≦ R _th (B) ≦ 250; 640 ≦ R _e (A) ≦ 700, -350 ≦ R _th (A) ≦ −320, 20 ≦ R _e (B) ≦ 100, 10 ≦ R _th (B) ≦ 50. Further preferred combinations include _{30 ≦ R e (A) ≦} 320, -160 ≦ R th (A) ≦ -15,30 ≦ R e (B) ≦ 320,20 ≦ R th (B) ≦ 320 . Particularly preferred combinations include 70 ≦ R _e (A) ≦ 120, −65 ≦ R _th (A) ≦ −25, 50 ≦ R _e (B) ≦ 110, and 25 ≦ R _th (B) ≦ 70. . The most preferred combinations include _{70 ≦ R e (A) ≦} 110, -65 ≦ R th (A) ≦ -25,70 ≦ R e (B) ≦ 110,25 ≦ R th (B) ≦ 65 .

In the liquid crystal display device of the reference invention, the optical anisotropic body (A) and the optical anisotropic body (B) are arranged between the liquid crystal cell and the incident side polarizer, and the optical anisotropic body (A) and The slow axis in each plane of the optical anisotropic body (B) is in a substantially parallel positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is a liquid crystal cell in which no voltage is applied. It is particularly preferable that the optically anisotropic body (A) is disposed on the liquid crystal cell side and is in a substantially vertical positional relationship with the slow axis in the plane. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell and the two polarizers take this positional relationship, so that the minimum contrast value can be obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 30 or more. FIG. 3 is an explanatory diagram of one mode of the liquid crystal display device of the reference invention. In this aspect, the incident side polarizer 1, the optical anisotropic body (B) 4, the optical anisotropic body (A) 3, the liquid crystal cell 2, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. In the positional relationship, the slow axis in the plane of the optical anisotropic body (A) is perpendicular to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied.

In the liquid crystal display device of the reference invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the incident side polarizer, and the optical anisotropic body (A) and the optical anisotropic body are arranged. The slow axis in each plane of the rectangular parallelepiped (B) is set to a substantially parallel positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is set in the plane of the liquid crystal cell in the state where no voltage is applied. And the optically anisotropic body (B) can be disposed on the liquid crystal cell side. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell and the two polarizers take this positional relationship, so that the minimum contrast value can be obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 20 or more. FIG. 4 is an explanatory diagram of another embodiment of the liquid crystal display device of the reference invention. In this aspect, the incident side polarizer 1, the optical anisotropic body (A) 3, the optical anisotropic body (B) 4, the liquid crystal cell 2, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. There is a positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied.

In the reference invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the incident side polarizer, and the optical anisotropic body (A) is disposed on the liquid crystal cell side. The in-plane retardation R _e (A) (unit: nm), the thickness direction retardation R _th (A) (unit: nm) of the optical anisotropic body (A), and the optical anisotropic body (B) Preferred combinations of in-plane retardation R _e (B) (unit: nm) and thickness direction retardation R _th (B) (unit: nm) are 10 ≦ R _e (A) ≦ 1000, −500 ≦ R _th ( A) ≦ −5, 10 ≦ R _e (B) ≦ 1000, 5 ≦ R _th (B) ≦ 500. More preferable combinations include 150 ≦ R _e (A) ≦ 470, −235 ≦ R _th (A) ≦ −75, 20 ≦ R _e (B) ≦ 480, 10 ≦ R _th (B) ≦ 240; 640 ≦ R _e (A) ≦ 760, −380 ≦ R _th (A) ≦ −320, 370 ≦ R _e (B) ≦ 470, 185 ≦ R _th (B) ≦ 235. More preferable combinations include 320 ≦ R _e (A) ≦ 400, −200 ≦ R _th (A) ≦ −160, 50 ≦ R _e (B) ≦ 170, and 25 ≦ R _th (B) ≦ 85. . The most preferable combinations satisfy 340 ≦ R _e (A) ≦ 380, −200 ≦ R _th (A) ≦ −160, 90 ≦ R _e (B) ≦ 130, and 35 ≦ R _th (B) ≦ 75. Is mentioned.
In the reference invention, the optical anisotropic body (A) and the optical anisotropic body (B) are disposed between the liquid crystal cell and the incident side polarizer, and the optical anisotropic body (B) is disposed on the liquid crystal cell side. The in-plane retardation R _e (A) (unit: nm), the thickness direction retardation R _th (A) (unit: nm) of the optical anisotropic body (A), and the optical anisotropic body (B) Preferred combinations of in-plane retardation R _e (B) (unit: nm) and thickness direction retardation R _th (B) (unit: nm) are 10 ≦ R _e (A) ≦ 1000, −500 ≦ R _th ( A) ≦ −5, 100 ≦ R _e (B) ≦ 450, 50 ≦ R _th (B) ≦ 225. The most preferable combinations are 420 ≦ R _e (A) ≦ 460, −240 ≦ R _th (A) ≦ −200, 170 ≦ R _e (B) ≦ 210, and 75 ≦ R _th (B) ≦ 115. Is mentioned.

In the liquid crystal display device of the reference invention, the optical anisotropic body (A) is disposed between the liquid crystal cell and the exit side polarizer, and the optical anisotropic body (B) is disposed between the liquid crystal cell and the entrance side polarizer. The slow axes in the respective planes of the optical anisotropic body (A) and the optical anisotropic body (B) are in a substantially parallel positional relationship, and further, in the plane of the optical anisotropic body (A). It is preferable that the slow axis is substantially perpendicular to the in-plane slow axis of the liquid crystal cell in the state where no voltage is applied. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell and the two polarizers take this positional relationship, so that the minimum contrast value can be obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 30 or more. FIG. 5 is an explanatory diagram of another embodiment of the liquid crystal display device of the reference invention. In this aspect, the incident side polarizer 1, the optical anisotropic body (B) 4, the liquid crystal cell 2, the optical anisotropic body (A) 3, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. In the positional relationship, the slow axis in the plane of the optical anisotropic body (A) is perpendicular to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied.

In the liquid crystal display device of the reference invention, the optical anisotropic body (A) is disposed between the liquid crystal cell and the incident side polarizer, and the optical anisotropic body (B) is disposed between the liquid crystal cell and the output side polarizer. Arranged, the slow axes in the planes of the optical anisotropic body (A) and the optical anisotropic body (B) are in a substantially parallel positional relationship, and the slow phase in the plane of the optical anisotropic body (A) The axis can be in a positional relationship substantially parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied. The optically anisotropic body (A), the optically anisotropic body (B), the liquid crystal cell and the two polarizers take this positional relationship, so that the minimum contrast value can be obtained at polar angles of 0 to 80 ° and all azimuth angles. It can be 20 or more. FIG. 6 is an explanatory diagram of another embodiment of the liquid crystal display device of the reference invention. In this embodiment, the incident side polarizer 1, the optical anisotropic body (A) 3, the liquid crystal cell 2, the optical anisotropic body (B) 4, and the output side polarizer 5 are laminated in this order. The arrows in the figure represent the transmission axis for the polarizer, the in-plane slow axis in the absence of voltage for the liquid crystal cell, and the in-plane slow axis for the optical anisotropic body. That is, the slow axis in the plane of the optical anisotropic body (A) having a negative intrinsic birefringence value is parallel to the slow axis in the plane of the optical anisotropic body (B) having a positive intrinsic birefringence value. There is a positional relationship, and the slow axis in the plane of the optical anisotropic body (A) is parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied.

In the reference invention, the optical anisotropic body (B) is disposed between the liquid crystal cell and the incident side polarizer, the optical anisotropic body (A) is disposed between the liquid crystal cell and the output side polarizer, and In-plane retardation R _e (A of the optical anisotropic body (A) when the slow axes in the planes of the optical anisotropic body (A) and the optical anisotropic body (B) are in a substantially parallel positional relationship. ) (Unit: nm), thickness direction retardation R _th (A) (unit: nm), in-plane retardation R _e (B) (unit: nm) of optical anisotropic body (B), thickness direction retardation R _th Preferred combinations of (B) (unit: nm) are 10 ≦ R _e (A) ≦ 720, −360 ≦ R _th (A) ≦ −5, 10 ≦ R _e (B) ≦ 1000, 5 ≦ R _th ( B) ≦ 500. More preferable combinations include 170 ≦ R _e (A) ≦ 230, −115 ≦ R _th (A) ≦ −85, 400 ≦ R _e (B) ≦ 460, 200 ≦ R _th (B) ≦ 230; 270 ≦ R _e (A) ≦ 440, −220 ≦ R _th (A) ≦ −135, 20 ≦ R _e (B) ≦ 190, 10 ≦ R _th (B) ≦ 95. More preferable combinations include 310 ≦ R _e (A) ≦ 410, −205 ≦ R _th (A) ≦ −155, 50 ≦ R _e (B) ≦ 140, and 25 ≦ R _th (B) ≦ 70. . Most preferred combinations include 340 ≦ R _e (A) ≦ 380, −200 ≦ R _th (A) ≦ −160, 70 ≦ R _e (B) ≦ 110, 25 ≦ R _th (B) ≦ 65. .
In the reference invention, the optical anisotropic body (A) is disposed between the liquid crystal cell and the incident side polarizer, the optical anisotropic body (B) is disposed between the liquid crystal cell and the output side polarizer, and In-plane retardation R _e (A of the optical anisotropic body (A) when the slow axes in the planes of the optical anisotropic body (A) and the optical anisotropic body (B) are in a substantially parallel positional relationship. ) (Unit: nm), thickness direction retardation R _th (A) (unit: nm), in-plane retardation R _e (B) (unit: nm) of optical anisotropic body (B), thickness direction retardation R _th Preferred combinations of (B) (unit: nm) are 10 ≦ R _e (A) ≦ 1000, −500 ≦ R _th (A) ≦ −5, 120 ≦ R _e (B) ≦ 440, 60 ≦ R _th ( B) ≦ 220. The most preferable combinations are 40 ≦ R _e (A) ≦ 80, −50 ≦ R _th (A) ≦ −10, 340 ≦ R _e (B) ≦ 380, 160 ≦ R _th (B) ≦ 200. Is mentioned.

In the liquid crystal display device of the present invention, the polarizer to be used is a film made of an appropriate vinyl alcohol-based polymer according to the prior art, such as polyvinyl alcohol or partially formalized polyvinyl alcohol, and a film made of iodine or a dichroic dye. Appropriate treatments such as dyeing treatment with a chromatic substance, stretching treatment, cross-linking treatment and the like are performed in an appropriate order and method, and appropriate materials that transmit linearly polarized light when natural light is incident can be used. In particular, those excellent in light transmittance and degree of polarization are preferable. The thickness of the polarizer is generally 5 to 80 μm, but is not limited thereto.
For the purpose of protecting the polarizer, a polarizer protective film may be adhered to one or both sides of the polarizer via an appropriate adhesive layer.
An appropriate transparent film can be used as the polarizer protective film. Among them, a film made of a polymer excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferably used. Examples of the polymer include acetate resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and polymers having an alicyclic structure. And acrylic resins.
In the liquid crystal display device of the present invention, when the optical anisotropic body and the polarizer are in contact with each other, the optical anisotropic film can also be used as a protective film for the polarizer. By using the optically anisotropic film as a protective film for the polarizer, it is possible to reduce the thickness of the liquid crystal display device by omitting one protective film and to improve the durability of the polarizer.
In the liquid crystal display device of the present invention, the optical anisotropic body (A) is preferably formed by laminating a transparent resin layer on at least one side of the layer, and is formed by laminating a transparent resin layer on both sides of the layer. Is particularly preferred. By laminating a transparent resin layer on the layer of the optical anisotropic body (A), the optical anisotropic body (A) can be prevented from being broken or the wavelength dependence of the optical anisotropic body can be easily controlled. it can. In this case, the transparent resin layer is preferably substantially non-oriented from the viewpoint of efficiently utilizing the phase difference of the layer made of a material having a negative intrinsic birefringence value.
The transparent resin laminated with the optical anisotropic body (A) is not particularly limited as long as it has a thickness of 1 mm and a total light transmittance of 80% or more. For example, a polymer having an alicyclic structure; Chain olefin polymers such as polypropylene; polycarbonate polymers; polyester polymers; polysulfone polymers, polyethersulfone polymers; polystyrene polymers; polyvinyl alcohol polymers; cellulose acetate polymers; And vinyl chloride polymers; polymethacrylate polymers; and the like. Among these, a polymer having an alicyclic structure or a chain olefin polymer is preferable, and a polymer having an alicyclic structure is particularly preferable from the viewpoint of transparency, low hygroscopicity, dimensional stability, lightness, and the like. preferable.
The polymer having an alicyclic structure is as described in the material portion having a positive intrinsic birefringence value.
In addition, for transparent resins, antioxidants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, dispersants, chlorine scavengers, flame retardants, crystallization nucleating agents, and antiblocking agents are used as necessary. Agents, antifogging agents, mold release agents, pigments, organic or inorganic fillers, neutralizing agents, lubricants, decomposition agents, metal deactivators, antifouling agents, antibacterial agents and other resins, thermoplastic elastomers, etc. Known additives can be added as long as the effects of the invention are not impaired.
In the liquid crystal display device of the present invention, the residual volatile component content of the optical anisotropic body (A) and the optical anisotropic body (B) is preferably 0.1% by weight or less, and 0.05% by weight or less. More preferably, it is more preferably 0.02% by weight or less. If the amount of residual volatile components exceeds 0.1% by weight, the volatile components are released to the outside during use, causing dimensional changes in the optical anisotropic body and generating internal stress, resulting in uneven phase difference. May occur. Therefore, in the liquid crystal display device of the present invention, the residual volatile component content of the optical laminates (A) and (B) is in the above range, so that the liquid crystal display device can be used regardless of environmental changes even when used for a long time. Excellent stability of optical characteristics such as display unevenness of display and reduction of contrast do not occur.
The volatile component is a substance having a molecular weight of 200 or less contained in a trace amount in the optical anisotropic body, and examples thereof include a residual monomer and a solvent. The content of the volatile component can be quantified by analyzing the optical anisotropic body by gas chromatography as a total of substances having a molecular weight of 200 or less contained in the optical anisotropic body.

There is no particular limitation on the mode of the liquid crystal display device of the present invention. For example, in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous spin wheel alignment (CPA) mode, Examples thereof include a twisted nematic (TN) mode, a super twisted nematic (STN) mode, a hybrid alignment nematic (HAN) mode, and an optically compensated bend (OCB) mode. Among these, the present invention can be particularly preferably applied to the in-plane switching mode.
The in-plane switching mode uses liquid crystal molecules that are homogeneously aligned in the horizontal direction and two polarizers whose transmission axes point vertically and horizontally with respect to the front of the screen. When the screen is viewed obliquely from the top, bottom, left, and right directions, the two transmission axes are in a positional relationship in which they are perpendicular to each other, and the homogeneously aligned liquid crystal layer has little birefringence that occurs in the twisted mode liquid crystal layer. Contrast is obtained. On the other hand, when the screen is viewed obliquely from the direction of the azimuth angle of 45 °, the angle between the transmission axes of the two polarizers is shifted from 90 °, so that the transmitted light causes birefringence. Light leaks, and sufficient black cannot be obtained, resulting in a decrease in contrast. Between the two polarizers of the in-plane switching mode liquid crystal display device, an optical anisotropic body (A) having a negative intrinsic birefringence value and an optical anisotropic body (B) having a positive intrinsic birefringence value are provided. By disposing, the birefringence generated in the transmitted light is effectively compensated to prevent light leakage, and high contrast can be obtained at all azimuth angles.
In the present invention, when forming a liquid crystal display device, for example, appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, a backlight and a brightness enhancement film are arranged in one or more layers at appropriate positions. Can do.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In Examples , Reference Examples, and Comparative Examples, a polarizing plate [Sanlitz Corporation, LLC 2-9518] was used as a polarizer. As the liquid crystal cell, a liquid crystal cell having a thickness of 2.74 μm, positive dielectric anisotropy, birefringence Δn = 0.09884 with a wavelength of 550 nm, and a pretilt angle of 0 ° was used.
In Examples , Reference Examples and Comparative Examples, measurement and evaluation were performed by the following methods.
(1) Thickness The cross section of the film is observed and measured with an optical microscope. About a laminated body, it measures for every layer.
(2) Glass transition temperature Measured by differential scanning calorimetry (DSC) based on JIS K7121.
(3) Refractive index (nx, ny, nz), retardation (in-plane retardation, thickness direction retardation), and in-plane slow axis variation Automatic birefringence meter [Oji Scientific Instruments, KOBRA -21] to measure with light having a wavelength of 550 nm. The variation of the slow axis is determined by measuring the slow axis at intervals of 10 mm in the width direction of the optical anisotropic body, obtaining an arithmetic average value of the measured values, and taking the variation of the measured value from the average value.
(4) Residual volatile component 200 mg of the optical anisotropic body is put into a sample container of a glass tube having an inner diameter of 4 mm from which moisture and organic substances adsorbed on the surface are completely removed. Next, the container is heated at a temperature of 100 ° C. for 60 minutes, and the gas coming out of the container is continuously collected. The collected gas is analyzed by a thermal desorption gas chromatography-mass spectrometer (TDS-GC-MS), and the total amount of components having a molecular weight of 200 or less is measured as a residual volatile component.
(5) Viewing angle characteristics of liquid crystal display device An optical anisotropic body is disposed at a position adjacent to a liquid crystal cell of a liquid crystal display device in an in-plane switching (IPS) mode, and the display characteristics are visually observed. Also, the contrast is calculated by optical simulation using a 4 × 4 matrix and displayed as a contrast diagram.

Example 1 (Production of an optically anisotropic body (A) film having a negative intrinsic birefringence value)
[1] layer composed of norbornene-based polymer [Nippon Zeon Co., Ltd., ZEONOR 1020, glass transition temperature 105 ° C.], styrene-maleic anhydride copolymer [Nova Chemical Japan Co., Ltd., Dilark D332, glass transition temperature 130 [2] layer comprising [° C., oligomer content 3% by weight] and a [3] layer comprising a modified ethylene-vinyl acetate copolymer [Mitsubishi Chemical Corporation, Modic AP A543, Vicat softening point 80 ° C.] , [1] layer (15 μm)-[3] layer (5 μm)-[2] layer (100 μm)-[3] layer (5 μm)-[1] layer (15 μm) Obtained by molding. The unstretched laminate was uniaxially stretched with a tenter at a temperature of 140 ° C. and a magnification of 1.4 times to obtain a film of optically anisotropic body (A) having a thickness of 100 μm.
The obtained films have refractive indexes nx _A 1.5809, ny _A 1.5800, nz _A 1.5809, in-plane retardation R _e (A) is 90 nm, and thickness direction retardation R _th (A) Was −45 nm, the in-plane variation of slow axis was ± 0.05 °, and the residual volatile component content was 0.01% by weight or less.
Example 2 (Production of an optically anisotropic body (B) film having a positive intrinsic birefringence value)
A film composed of a norbornene polymer [Nippon ZEON Co., Ltd., ZEONOR 1420, glass transition temperature 135 ° C.] is uniaxially stretched by a nip roll at a temperature of 139 ° C. and a magnification of 1.1 times, and is 100 μm thick. A film of body (B) was obtained.
The obtained films had a refractive index of nx _B 1.5309, ny _B 1.5300, and nz _B 1.5300, an in-plane retardation R _e (B) of 90 nm, and a thickness direction retardation R _th (B). Was 45 nm, and the residual volatile component content was 0.01% by weight or less.

Example 3 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the in-plane slow axis when no voltage is applied to the liquid crystal cell are perpendicular to each other, and the in-plane slow axis when no voltage is applied to the liquid crystal cell and the surface of the optical anisotropic body (B) The slow axis in the plane is perpendicular, the slow axis in the plane of the optical anisotropic body (B) and the slow axis in the plane of the optical anisotropic body (A) are parallel, and the optical anisotropic body (A) Incident side polarizer, liquid crystal cell, optical anisotropic body (B) film, optical anisotropic body (A) film, and outgoing side so that the in-plane slow axis and the transmission axis of the outgoing side polarizer are perpendicular to each other. Polarizers were stacked in this order to assemble a liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 ° from all directions. FIG. 7 shows a contrast diagram obtained by simulation for this liquid crystal display device.
Example 4 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the in-plane slow axis when no voltage is applied to the liquid crystal cell are perpendicular to each other, and the in-plane slow axis when no voltage is applied to the liquid crystal cell and the surface of the optical anisotropic body (A) The slow axis in the plane of the optical anisotropic body (A), the slow axis in the plane of the optical anisotropic body (B), the slow axis in the plane of the optical anisotropic body (B) The incident side polarizer, the liquid crystal cell, the optical anisotropic body (A) film, the optical anisotropic body (B) film, and the outgoing side polarizer are arranged so that the transmission axis of the output side polarizer and the output side polarizer are parallel to each other. The liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 ° from all directions. FIG. 8 shows a contrast diagram obtained by simulation for this liquid crystal display device.

Reference Example 5 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the slow axis in the plane of the optical anisotropic body (B) are parallel, and the slow axis in the plane of the optical anisotropic body (B) and the plane of the optical anisotropic body (A) The slow axis in the plane is parallel, the slow axis in the plane of the optical anisotropic body (A) is perpendicular to the slow axis in the plane when no voltage is applied to the liquid crystal cell, and no voltage is applied to the liquid crystal cell. Incident side polarizer, optical anisotropic body (B) film, optical anisotropic body (A) film, liquid crystal cell, and output side so that the in-plane slow axis and the transmission axis of the output side polarizer are parallel. Polarizers were stacked in this order to assemble a liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 ° from all directions. FIG. 9 shows a contrast diagram obtained by simulation for this liquid crystal display device.
Reference Example 6 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the slow axis in the plane of the optical anisotropic body (A) are perpendicular, and the slow axis in the plane of the optical anisotropic body (A) and the plane of the optical anisotropic body (B) In the plane of the optical anisotropic body (B), the in-plane slow axis when no voltage is applied to the liquid crystal cell, and the in-plane slow axis when no voltage is applied to the liquid crystal cell. The incident side polarizer, the optical anisotropic body (A) film, the optical anisotropic body (B) film, the liquid crystal cell, and the outgoing side polarizer are arranged so that the transmission axis of the output side polarizer and the output side polarizer are parallel to each other. The liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and uniform when viewed from the front, but the contrast was low when viewed from an oblique direction with an azimuth angle of 45 °. was there. FIG. 10 shows a contrast diagram obtained by simulation for this liquid crystal display device.

Reference Example 7 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the slow axis in the plane of the optical anisotropic body (B) are parallel, and the slow axis in the plane of the optical anisotropic body (B) and the surface when no voltage is applied to the liquid crystal cell The slow axis in the liquid crystal cell is vertical, the slow axis in the plane when no voltage is applied to the liquid crystal cell and the slow axis in the plane of the optical anisotropic body (A) are vertical, and the optical anisotropic body (A) Incident side polarizer, optical anisotropic body (B) film, liquid crystal cell, optical anisotropic body (A) film, and outgoing side so that the in-plane slow axis and the transmission axis of the outgoing side polarizer are perpendicular to each other. Polarizers were stacked in this order to assemble a liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and uniform when viewed from the front, but the contrast was slightly when viewed from an oblique direction with an azimuth angle of 45 °. There was a low part. FIG. 11 shows a contrast diagram obtained by simulation for this liquid crystal display device.
Reference Example 8 (Production of liquid crystal display device)
The transmission axis of the incident side polarizer and the slow axis in the plane of the optical anisotropic body (A) are perpendicular to each other, and the slow axis in the plane of the optical anisotropic body (A) and the plane when no voltage is applied to the liquid crystal cell The slow axis in the plane, the slow axis in the plane when no voltage is applied to the liquid crystal cell, the slow axis in the plane of the optical anisotropic body (B), and the slow axis in the plane of the optical anisotropic body (B) The incident side polarizer, the optical anisotropic body (A) film, the liquid crystal cell, the optical anisotropic body (B) film, and the output side polarizer are arranged so that the transmission axis of the output side polarizer and the output side polarizer are parallel to each other. The liquid crystal display device having the configuration shown in FIG.
When the display characteristics of the obtained liquid crystal display device were visually evaluated, the display was good and uniform when viewed from the front, but the contrast was low when viewed from an oblique direction with an azimuth angle of 45 °. was there. FIG. 12 shows a contrast diagram obtained by simulation for this liquid crystal display device.
Comparative Example 1
The transmission axis of the incident side polarizer is parallel to the in-plane slow axis when no voltage is applied to the liquid crystal cell, and the in-plane slow axis when no voltage is applied to the liquid crystal cell and the transmission axis of the exit side polarizer are The liquid crystal display device was assembled by stacking the incident side polarizer, the liquid crystal cell, and the output side polarizer in this order so as to be vertical.
When the display characteristics of the obtained liquid crystal display device were evaluated visually, the display was good when the screen was viewed from the front, but when viewed from an oblique direction with an azimuth angle of 45 °, the contrast was low and the display was poor. there were. FIG. 13 shows a contrast diagram obtained by simulation for this liquid crystal display device.

  The liquid crystal display device of the present invention prevents a decrease in contrast when the screen is viewed from an oblique direction without deteriorating image characteristics from the front direction, has a wide viewing angle, and is uniform and high when viewed from any direction. Has contrast. The liquid crystal display device of the present invention can be particularly suitably applied to an in-plane switching mode liquid crystal display device.

It is explanatory drawing of the one aspect | mode of the liquid crystal display device of this invention. It is explanatory drawing of the other aspect of the liquid crystal display device of this invention. It is explanatory drawing of the one aspect | mode of the liquid crystal display device of reference invention. It is explanatory drawing of the other aspect of the liquid crystal display device of reference invention. It is explanatory drawing of the other aspect of the liquid crystal display device of reference invention. It is explanatory drawing of the other aspect of the liquid crystal display device of reference invention. 6 is a contrast diagram of a liquid crystal display device obtained in Example 3. FIG. 6 is a contrast diagram of a liquid crystal display device obtained in Example 4. FIG. 10 is a contrast diagram of a liquid crystal display device obtained in Reference Example 5. FIG. 10 is a contrast diagram of a liquid crystal display device obtained in Reference Example 6. FIG. 10 is a contrast diagram of a liquid crystal display device obtained in Reference Example 7. FIG. 10 is a contrast diagram of a liquid crystal display device obtained in Reference Example 8. FIG. 6 is a contrast diagram of a liquid crystal display device obtained in Comparative Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incident side polarizer 2 Liquid crystal cell 3 Optical anisotropic body (A)
4 Optical anisotropic bodies (B)
5 Output polarizer

Claims (5)

An in-plane switching mode liquid crystal display device having at least an optically anisotropic body (A), an optically anisotropic body (B), and a liquid crystal cell between a pair of polarizers whose transmission axes are substantially perpendicular to each other. Because
A liquid crystal cell, an optical anisotropic body (B) and an optical anisotropic body (A) are provided in this order,
The optical anisotropic body (A) is composed of a material layer having a negative intrinsic birefringence value,
The optical anisotropic body (B) is made of a material layer having a positive intrinsic birefringence value,
The slow axis in the plane of the optical anisotropic body (A) and the slow axis in the plane of the optical anisotropic body (B) are in a substantially parallel positional relationship.
The slow axis in the plane of the optical anisotropic body (A) is in a substantially vertical positional relationship with the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied,
The slow axis in the plane of the optical anisotropic body (A) is substantially parallel or substantially perpendicular to the transmission axis of the polarizer disposed in the vicinity,
In-plane retardation of the optical anisotropic body (A) is 60 nm or more and 110 nm or less,
The thickness direction retardation of the optical anisotropic body (A) is −70 nm or more and −25 nm or less,
In-plane retardation of the optical anisotropic body (B) is 70 nm or more and 120 nm or less,
Thickness direction retardation der than 65nm or less 25nm of optically anisotropic member (B) is,
Refractive indexes in the slow axis direction in the respective planes of the optical anisotropic body (A) and optical anisotropic body (B) measured with light having a wavelength of 550 nm are nx _A and nx _B , and the slow axis and the plane are in-plane. When the refractive index in the orthogonal direction is ny _A and ny _B and the refractive index in the thickness direction is nz _A and nz _B , the absolute value of the difference between nx _A and nz _A is 0.003 or less, and ny _B and the liquid crystal display device of in-plane switching mode in which the absolute value of the difference between nz _B is characterized der Rukoto 0.003. An in-plane switching mode liquid crystal display device having at least an optically anisotropic body (A), an optically anisotropic body (B), and a liquid crystal cell between a pair of polarizers whose transmission axes are substantially perpendicular to each other. Because
A liquid crystal cell, an optical anisotropic body (A) and an optical anisotropic body (B) are provided in this order,
The optical anisotropic body (A) is composed of a material layer having a negative intrinsic birefringence value,
The optical anisotropic body (B) is made of a material layer having a positive intrinsic birefringence value,
The slow axis in the plane of the optical anisotropic body (A) and the slow axis in the plane of the optical anisotropic body (B) are in a substantially parallel positional relationship.
The slow axis in the plane of the optical anisotropic body (A) is substantially parallel to the slow axis in the plane of the liquid crystal cell in the state where no voltage is applied,
The slow axis in the plane of the optical anisotropic body (A) is substantially parallel or substantially perpendicular to the transmission axis of the polarizer disposed in the vicinity,
In-plane retardation of the optical anisotropic body (A) is 70 nm or more and 120 nm or less,
The thickness direction retardation of the optical anisotropic body (A) is −65 nm or more and −25 nm or less,
In-plane retardation of the optical anisotropic body (B) is 50 nm or more and 110 nm or less,
Thickness direction retardation der than 70nm or less 25nm of optically anisotropic member (B) is,
Refractive indexes in the slow axis direction in the respective planes of the optical anisotropic body (A) and optical anisotropic body (B) measured with light having a wavelength of 550 nm are nx _A and nx _B , and the slow axis and the plane are in-plane. When the refractive index in the orthogonal direction is ny _A and ny _B and the refractive index in the thickness direction is nz _A and nz _B , the absolute value of the difference between nx _A and nz _A is 0.003 or less, and ny _B and the liquid crystal display device of in-plane switching mode in which the absolute value of the difference between nz _B is characterized der Rukoto 0.003. n z _A> ny _A, and, nx _B> liquid crystal display device according to claim 1 or 2, wherein satisfies the nz _B. Optically anisotropic member (A) is a liquid crystal display device according to any one of claims 1 to 3 formed by laminating at least a transparent resin layer on one surface of the layer. The liquid crystal display device according to any one of claims 1 to 4 , wherein a residual volatile component content of the optical anisotropic body (A) and the optical anisotropic body (B) is 0.1 wt% or less.

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