JP2007213093A - Liquid crystal panel and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel and a liquid crystal display exhibiting excellent screen contrast, little color shift and little unevenness in display. <P>SOLUTION: The liquid crystal panel comprises a liquid crystal cell, a first polarizer arranged on one side of the liquid crystal cell, a second polarizer arranged on the other side of the liquid crystal cell, and at least two optical compensation layers including a first optical compensation layer and a second optical compensation layer arranged between the first polarizer and the second polarizer. The first optical compensation layer has the absolute value of photoelasticity coefficient not larger than 40×10<SP>-12</SP>(m<SP>2</SP>/N) and relations expressed by formula (1), Δnd(380)<Δnd(550)<Δnd(780), and formula (2), nx>ny≥nz, and the second optical compensation layer has relations expressed by formula (3), Rth(380)>Rth(550)>Rth(780) and formula (4), nx=ny>nz, wherein Δnd(380), Δnd(550) and Δnd(780) represent retardations within the plane measured at wavelengths of 380nm, 550 nm and 780 nm at 23°C, respectively; Rth(380), Rth(550) and Rth(780) represent retardations in the thickness direction measured at wavelengths of 380nm, 550 nm and 780 nm at 23°C, respectively, and nx, ny and nz represent refractive indices in the slow phase axis direction, fast phase axis direction and the thickness direction, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device. More specifically, the present invention relates to a liquid crystal panel and a liquid crystal display device having at least two optical compensation layers between a first polarizer and a second polarizer.

  In the VA mode or OCB mode liquid crystal cell, liquid crystal molecules are aligned in the vertical direction when no voltage is applied. Therefore, when the liquid crystal panel is viewed from an oblique direction, the liquid crystal molecules are apparently aligned in the oblique direction, and the polarization state of the light from the oblique direction changes due to the birefringence of the liquid crystal, thereby Light leakage from the plate occurs. Also, polarizing plates block light by arranging them so that their absorption axes are perpendicular to each other. However, when the polarizing plates in such a laminated state are viewed from an oblique direction, the absorption of the polarizing plates is apparently apparent. The axes become non-orthogonal, and light leakage from the polarizing plate occurs.

In order to solve the above problems, the relationship of nx>ny> nz (nx is the refractive index in the slow axis direction, ny is the refractive index in the fast axis direction, and nz is the refractive index in the thickness direction) Techniques have been disclosed that compensate for the effects of liquid crystal birefringence and polarizing plate misalignment on light leakage using a biaxial optical compensator that is provided (see, for example, Patent Documents 1 to 5). However, these techniques are insufficient in improving screen contrast, reducing color shift, and suppressing display unevenness.
Japanese Patent Application No. 2003-926 Japanese Patent Application No. 2003-27488 Japanese Patent Application No. 2003-38734 Japanese Patent Application No. 2002-63796 Japanese Patent Application No. 2002-222830

  The present invention has been made to solve the above-described conventional problems. The object of the present invention is to provide a liquid crystal with excellent screen contrast, small color shift, and small display unevenness without adding complicated means. A panel and a liquid crystal display device are provided.

The liquid crystal panel of the present invention comprises: 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 at least two optical compensation layers including a first optical compensation layer and a second optical compensation layer, which are disposed between the second polarizer and the second polarizer. The absolute value of the photoelastic coefficient is 40 × 10 ⁻¹² (m ² / N) or less, and the first optical compensation layer has a relationship of the following formulas (1) and (2), The optical compensation layer 2 has a relationship of the following formulas (1) and (2).
Δnd (380) <Δnd (550) <Δnd (780) (1)
nx> ny ≧ nz (2)
Rth (380)> Rth (550)> Rth (780) (3)
nx = ny> nz (4)
Here, Δnd (380), Δnd (550), and Δnd (780) represent in-plane phase differences measured at wavelengths of 380 nm, 550 nm, and 780 nm at 23 ° C., respectively, and Rth (380), Rth (550) And Rth (780) represent thickness direction retardation measured at 23 ° C. at wavelengths of 380 nm, 550 nm, and 780 nm, respectively, and nx, ny, and nz represent the slow axis direction, the fast axis direction, and the thickness direction, respectively. Represents the refractive index.

  In a preferred embodiment, the first optical compensation layer has a relationship of Δnd (780) / Δnd (550)> 1.10.

  In a preferred embodiment, the first optical compensation layer includes a cellulosic material.

  In a preferred embodiment, the cellulose material has an acetyl substitution degree (DSac) and a propionyl substitution degree (DSpr) of 2.0 ≦ DSac + DSpr ≦ 3.0 and 1.0 ≦ DSpr ≦ 3.0.

  In a preferred embodiment, the second optical compensation layer has a relationship of Rth (780) / Rth (550) <0.95.

  In a preferred embodiment, the material constituting the second optical compensation layer is at least one non-liquid crystalline polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide. It is.

  In a preferred embodiment, the first optical compensation layer and the second optical compensation layer are disposed on different sides with respect to the liquid crystal cell.

  In a preferred embodiment, the first optical compensation layer has a relationship of 90 nm ≦ Δnd (550) ≦ 200 nm, and the protective layer on the liquid crystal cell side of the first polarizer or the second polarizer. Function as.

In another embodiment, the liquid crystal panel further includes a protective layer having a relationship of the following formulas (5) and (6) on the liquid crystal cell side of the first polarizer or the second polarizer, The first optical compensation layer is disposed on the liquid crystal cell side of the protective layer, and the first optical compensation layer has a relationship of 50 nm ≦ Δnd (550) ≦ 150 nm:
0 nm ≦ Δnd (550) ≦ 10 nm (5)
40 nm ≦ Rth (550) ≦ 80 nm (6).

  In a preferred embodiment, the liquid crystal cell is a VA mode or an OCB mode.

  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.

As described above, according to the present invention, the first optical compensation layer and the second optical compensation layer having the above optical characteristics are disposed between the first polarizer and the second polarizer. Thus, the screen contrast can be improved and the color shift can be reduced. Further, by providing the first optical compensation layer having an absolute value of the photoelastic coefficient of 40 × 10 ⁻¹² (m ² / N) or less, the retardation unevenness caused by the contraction stress of the polarizer and the heat of the backlight is reduced. This can prevent display unevenness. As a result, it is possible to provide a liquid crystal panel and a liquid crystal display device that are excellent in screen contrast, small in color shift, and small in display unevenness without adding complicated means.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows:
(1) “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 perpendicular to the slow axis in the plane (ie, fast phase) (Nz direction), and “nz” is the refractive index in the thickness direction. For example, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. In this specification, “substantially equal” is intended to include the case where nx and ny are different within a range that does not practically affect the overall polarization characteristics of the polarizing plate with an optical compensation layer.
(2) “In-plane retardation Δnd (550)” refers to a retardation value in a layer (film) plane measured with light having a wavelength of 550 nm at 23 ° C. Δnd (550) is an equation when the refractive index in the slow axis direction and the fast axis direction of the layer (film) at a wavelength of 550 nm is nx and ny, respectively, and d (nm) is the thickness of the layer (film). : Δnd = (nx−ny) × d. The “in-plane retardation Δnd (380)” refers to the retardation value in the layer (film) plane measured with light having a wavelength of 380 nm at 23 ° C., and the “in-plane retardation Δnd (780)” refers to 23 The retardation value in the layer (film) plane measured with light having a wavelength of 780 nm at ° C.
(3) “Thickness direction retardation Rth (550)” refers to a thickness direction retardation value measured at 23 ° C. with light having a wavelength of 550 nm. Rth (550) is a formula when the refractive index in the slow axis direction and the thickness direction of the layer (film) at a wavelength of 550 nm is nx and nz, and d (nm) is the thickness of the layer (film): = (Nx−nz) × d. The “thickness direction retardation Rth (380)” is a thickness direction retardation value measured with light having a wavelength of 380 nm at 23 ° C., and the “thickness direction retardation Rth (780)” is 23 ° C. The thickness direction retardation value measured with light having a wavelength of 780 nm.

A. Overall Configuration of Liquid Crystal Panel FIG. 1A is a schematic cross-sectional view of a liquid crystal panel according to one embodiment of the present invention. The liquid crystal panel 100 includes a liquid crystal cell 10; a first polarizer 20 disposed on one side of the liquid crystal cell 10 (viewing side in the illustrated example); and the other side of the liquid crystal cell 10 (backlight in the illustrated example). A second polarizer 20 ′ disposed on the side); and at least two optical compensation layers disposed between the first polarizer 20 and the second polarizer 20 ′. The at least two optical compensation layers include a first optical compensation layer 30 and a second optical compensation layer 40. In the illustrated example, the first optical compensation layer 30 is disposed between the first polarizer 20 and the liquid crystal cell 10, and the second optical compensation layer 40 is composed of the second polarizer 20 ′ and the liquid crystal cell 10. It is arranged between. According to such an embodiment, the first optical compensation layer 30 can function as a protective layer on the liquid crystal cell side of the first polarizer 20, so that the liquid crystal panel (finally, a liquid crystal display device) is thin. Can contribute. FIG. 1B is a schematic cross-sectional view of a liquid crystal panel according to another embodiment of the present invention. In this embodiment, a protective layer 50 is provided between the first polarizer 20 and the first optical compensation layer 30. The protective layer 50 is adjacent to the liquid crystal cell side of the first polarizer 20, and the first optical compensation layer 30 is adjacent to the liquid crystal cell side of the protective layer 50. According to such an embodiment, by providing the protective layer 50, deterioration of the polarizer can be remarkably prevented and a liquid crystal panel excellent in durability can be obtained. The first optical compensation layer 30 may be disposed on the backlight side, and the second optical compensation layer 40 may be disposed on the viewing side. However, the first optical compensation layer 30 is preferably visible as illustrated. Placed on the side. This is because the effect of the present invention can be further exerted by reducing the influence of the backlight on heat.

  FIG. 2A is a schematic cross-sectional view of a liquid crystal panel according to another embodiment of the present invention. In this embodiment, the first optical compensation layer 30 and the second optical compensation layer 40 are disposed between the first polarizer 20 and the liquid crystal cell 10. According to such an embodiment, the first optical compensation layer 30 can function as a protective layer on the liquid crystal cell side of the first polarizer 20, so that the liquid crystal panel (finally, a liquid crystal display device) is thin. Can contribute. FIG. 2B is a schematic cross-sectional view of a liquid crystal panel according to another embodiment of the present invention. In this embodiment, a protective layer 50 is provided between the first polarizer 20 and the first optical compensation layer 30. The protective layer 50 is adjacent to the liquid crystal cell side of the first polarizer 20, and the first optical compensation layer 30 is adjacent to the liquid crystal cell side of the protective layer 50. According to such an embodiment, by providing the protective layer 50, the deterioration of the polarizer can be remarkably prevented, and a liquid crystal panel excellent in durability can be obtained. Note that the arrangement of the first optical compensation layer 30 and the second optical compensation layer 40 may be switched.

  As shown in FIG. 1A and FIG. 1B, the first optical compensation layer 30 and the second optical compensation layer 40 are disposed on different sides with respect to the liquid crystal cell 10, respectively. Is preferred. This is because product design can be performed without considering the method of laminating the first optical compensation layer 30 and the second optical compensation layer 40, and the productivity is excellent. In addition, the detail of each structural member and each layer which are shown to Fig.1 (a)-(b) and Fig.2 (a)-(b) is demonstrated by the below-mentioned B-1 term-B-4 term.

  In the present invention, any appropriate protective film (not shown) is provided between the first polarizer 20 or the second polarizer 20 ′ and the second optical compensation layer 40 as necessary. It is done. Furthermore, if necessary, any appropriate protective film is provided on the side of the first polarizer 20 and / or the second polarizer 20 'where the optical compensation layer is not formed. By providing the protective film, deterioration of the polarizer can be prevented. In the present invention, another optical compensation layer (not shown) may be provided. The type, number, arrangement position, and the like of such an optical compensation layer can be appropriately selected according to the purpose.

  The liquid crystal cell 10 includes a pair of substrates 11 and 11 ′ and a liquid crystal layer 12 as a display medium sandwiched between the substrates 11 and 11 ′. One substrate (color filter substrate) 11 is provided with a color filter and a black matrix (both not shown). On the other substrate (active matrix substrate) 11 ′, a switching element (typically TFT) (not shown) for controlling the electro-optical characteristics of the liquid crystal and a scanning line (not shown) for supplying a gate signal to this switching element. ) And a signal line (not shown) for supplying a source signal, and a pixel electrode (not shown). The color filter may be provided on the active matrix substrate 11 'side. A distance (cell gap) between the substrates 11 and 11 'is controlled by a spacer (not shown). An alignment film (not shown) made of, for example, polyimide is provided on the side of the substrates 11 and 11 ′ in contact with the liquid crystal layer 12.

  As a driving mode of the liquid crystal cell 10, any appropriate driving mode can be adopted as long as the effect of the present invention can be obtained. Specific examples of the drive mode include STN (Super Twisted Nematic) mode, TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, VA (Vertical Aligned Hidden Alignment) mode, OCB (Optical Aligned Hidden mode) Examples include an aligned nematic (ASM) mode and an ASM (axially aligned microcell) mode. VA mode and OCB mode are preferred.

  FIG. 3 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in FIG. 3A, when no voltage is applied, the liquid crystal molecules are aligned perpendicular to the surfaces of the substrates 11 and 11 '. Such vertical alignment can be realized by arranging a nematic liquid crystal having negative dielectric anisotropy between substrates on which a vertical alignment film (not shown) is formed. When light is incident from the surface of one substrate 11 in such a state, the linearly polarized light that has passed through the first polarizer 20 and entered the liquid crystal layer 12 is the major axis of the vertically aligned liquid crystal molecules. Proceed along the direction of Since birefringence does not occur in the major axis direction of the liquid crystal molecules, the incident light travels without changing the polarization direction and is absorbed by the second polarizer 20 ′ having a polarization axis orthogonal to the first polarizer 20. This provides a dark display when no voltage is applied (normally black mode). As shown in FIG. 3B, when a voltage is applied between the electrodes, the long axes of the liquid crystal molecules are aligned parallel to the substrate surface. Liquid crystal molecules exhibit birefringence with respect to linearly polarized light incident on the liquid crystal layer 12 in this state, and the polarization state of incident light changes according to the inclination of the liquid crystal molecules. Light that passes through the liquid crystal layer when a predetermined maximum voltage is applied becomes, for example, linearly polarized light whose polarization direction is rotated by 90 °, and therefore, a bright display can be obtained through the second polarizer 20 ′. . When the voltage is not applied again, the display can be returned to the dark state by the orientation regulating force. Further, gradation display can be performed by changing the intensity of transmitted light from the second polarizer 20 'by changing the applied voltage to control the tilt of the liquid crystal molecules.

  FIG. 4 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the OCB mode. The OCB mode is a drive mode in which the liquid crystal layer 12 is configured by so-called bend alignment. As shown in FIG. 4C, the bend alignment has a substantially parallel angle (alignment angle) when the alignment of nematic liquid crystal molecules is in the vicinity of the substrate, and the alignment plane increases toward the center of the liquid crystal layer. An alignment state that exhibits an angle perpendicular to the liquid crystal layer, gradually changes so as to be aligned with the opposing substrate surface as the distance from the center of the liquid crystal layer, and does not have a twisted structure throughout the liquid crystal layer. Such a bend orientation is formed as follows. As shown in FIG. 4A, in a state where no electric field or the like is applied (initial state), the liquid crystal molecules are substantially homogeneously aligned. However, the liquid crystal molecules have a pretilt angle, and the pretilt angle near the substrate is different from the pretilt angle near the opposite substrate. When a predetermined bias voltage (typically, 1.5 V to 1.9 V) is applied thereto (when a low voltage is applied), a splay alignment as shown in FIG. A transition to bend orientation as shown can be achieved. When a display voltage (typically 5 V to 7 V) is applied from the bend alignment state (when a high voltage is applied), the liquid crystal molecules rise almost perpendicularly to the substrate surface as shown in FIG. In the normally white display mode, light that has passed through the first polarizer 20 and entered the liquid crystal layer in the state of FIG. 4D when a high voltage is applied proceeds without changing the polarization direction. 2 is absorbed by the polarizer 20 '. Therefore, a dark state is displayed. When the display voltage is lowered, it can return to the bend alignment and return to the bright display by the alignment regulating force of the rubbing process. In addition, gradation display is possible by changing the display voltage to control the tilt of the liquid crystal molecules to change the transmitted light intensity from the polarizer. Note that a liquid crystal display device having an OCB mode liquid crystal cell can switch the phase transition from the splay alignment state to the bend alignment state at a very high speed, so that the liquid crystal display device in other drive modes such as the TN mode and the IPS mode can be used. In comparison, it has a feature of excellent moving image display characteristics.

B-1. First optical compensation layer The absolute value of the photoelastic coefficient of the first optical compensation layer is 40 × 10 ⁻¹² m ² / N or less, more preferably 0.2 × 10 ^{−12 to} 35 × 10 ^−12. , more preferably from ^{0.2 × 10 -12 ~30 × 10 -12} . If the absolute value of the photoelastic coefficient is within such a range, display unevenness can be effectively suppressed.

  The first optical compensation layer has a refractive index distribution of nx> ny ≧ nz. Furthermore, the first optical compensation layer has so-called reverse dispersion wavelength dependency. Specifically, the in-plane phase difference has a relationship of Δnd (380) <Δnd (550) <Δnd (780). Preferably, the in-plane phase difference has a relationship of Δnd (780) / Δnd (550)> 1.10. By having such a relationship, good optical compensation can be realized over a wide range of visible light. One feature of the present invention is that a liquid crystal panel having an optical compensation layer that achieves both the low photoelastic coefficient and the wavelength dependence of inverse dispersion as described above is realized.

  As shown in FIG. 1A or FIG. 2A, in an embodiment in which the first optical compensation layer can function as a protective layer on the liquid crystal cell side of the first polarizer or the second polarizer, The lower limit of the in-plane retardation Δnd (550) of one optical compensation layer is preferably 90 nm or more, more preferably 120 nm or more, and further preferably 130 nm or more. On the other hand, the upper limit of Δnd (550) is preferably 200 nm or less, more preferably 170 nm or less, and still more preferably 160 nm or less. In this embodiment, the lower limit of the thickness direction retardation Rth (550) of the first optical compensation layer is preferably 120 nm or more, more preferably 140 nm or more, and further preferably 160 nm or more. On the other hand, the upper limit of Rth (550) is preferably 250 nm or less, more preferably 230 nm or less, and still more preferably 210 nm or less.

  As shown in FIG. 1B or FIG. 2B, a protective layer is provided between the first polarizer or the second polarizer and the first optical compensation layer, and the first optical compensation layer is provided. In an embodiment in which is adjacent to the liquid crystal cell side of the protective layer, the lower limit of the in-plane retardation Δnd (550) of the first optical compensation layer is preferably 50 nm or more, more preferably 70 nm or more, and even more preferably 75 nm or more. is there. On the other hand, the upper limit of Δnd (550) is preferably 150 nm or less, more preferably 110 nm or less, and still more preferably 100 nm or less. In this embodiment, the lower limit of the thickness direction retardation Rth (550) of the first optical compensation layer is preferably 50 nm or more, more preferably 70 nm or more, and further preferably 75 nm or more. On the other hand, the upper limit of Rth (550) is preferably 150 nm or less, more preferably 130 nm or less, and still more preferably 110 nm or less.

  Any appropriate thickness can be adopted as the thickness of the first optical compensation layer as long as the effects of the present invention are exhibited. Specifically, the thickness is preferably 20 to 160 μm, more preferably 40 to 140 μm, and still more preferably 60 to 120 μm.

  The first optical compensation layer can be typically formed by stretching a polymer film. For example, the first optical compensation layer having the above optical characteristics (refractive index distribution, in-plane retardation, photoelastic coefficient) can be obtained by appropriately selecting the type of polymer, stretching conditions, stretching method, and the like. obtain.

  Any appropriate material can be adopted as the material included in the polymer film, but it is preferable to include a cellulosic material.

  The cellulose material is preferably substituted with an acetyl group and a propionyl group. Degree of substitution of this cellulosic material, “DSac (acetyl substitution degree) + DSpr (propionyl substitution degree)” (how many three hydroxyl groups present in the repeating unit of cellulose are substituted with an acetyl group or a propionyl group on average. Is preferably 2 or more, more preferably 2.3 or more, and even more preferably 2.6 or more. The upper limit of “DSac + DSpr” is preferably 3 or less, more preferably 2.9 or less, and even more preferably 2.8 or less. By setting the substitution degree of the cellulosic material in the above range, an optical compensation layer having the desired refractive index distribution as described above can be obtained.

  The lower limit of the DSpr (propionyl substitution degree) is preferably 1 or more, more preferably 2 or more, and further preferably 2.5 or more. The upper limit of DSpr is preferably 3 or less, more preferably 2.9 or less, and even more preferably 2.8 or less. By setting DSpr in the above range, the solubility of the cellulose-based material in the solvent is improved, and the thickness of the first optical compensation layer to be obtained can be easily controlled. Furthermore, by setting “DSac + DSpr” in the above range and DSpr in the above range, an optical compensation layer having the above optical characteristics and having the wavelength dependence of reverse dispersion can be obtained.

  The DSac (acetyl substitution degree) and DSpr (propionyl substitution degree) can be determined by the method described in JP-A No. 2003-315538 [0016] to [0019].

  The cellulosic material may have other substituents other than acetyl groups and propionyl groups. Examples of other substituents include ester groups such as butyrate; ether groups such as alkyl ether groups and aralkylene ether groups.

  The number average molecular weight of the cellulosic material is preferably 5,000 to 100,000, more preferably 10,000 to 70,000. By setting it as the said range, it is excellent in productivity and favorable mechanical strength can be obtained.

  As a method for substituting the acetyl group and the propionyl group, any method is appropriately adopted. For example, cellulose is treated with a strong caustic soda solution to obtain alkali cellulose, which is acylated with a mixture of a predetermined amount of acetic anhydride and propionic anhydride. The substitution degree “DSac + DSpr” is adjusted by partially hydrolyzing the acyl group.

  The polymer film can appropriately contain any polymer material. Examples of such a polymer material include cellulose esters such as cellulose butyrate; cellulose ethers such as methyl cellulose and ethyl cellulose. The polymer film may contain additives such as a plasticizer, a heat stabilizer, and an ultraviolet stabilizer as necessary.

B-2. Second Optical Compensation Layer The second optical compensation layer has a refractive index distribution of nx = ny> nz. Further, the thickness direction retardation of the second optical compensation layer has a relationship of Rth (380)> Rth (550)> Rth (780). Preferably, the retardation in the thickness direction has a relationship of Rth (780) / Rth (550) <0.95.

  The lower limit of the thickness direction retardation Rth (550) of the second optical compensation layer is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 50 nm or more. On the other hand, the upper limit of Rth (550) is preferably 1000 nm or less, more preferably 500 nm or less, and still more preferably 250 nm or less. The upper limit of the in-plane retardation Δnd (550) of the second optical compensation layer is 10 nm or less, preferably 5 nm or less, more preferably 3 nm or less.

  The second optical compensation layer may be a single layer or a laminate of two or more layers. In the case of a laminate, the material constituting each layer and the thickness of each layer can be appropriately set as long as the entire laminate has the optical characteristics as described above.

  Any appropriate thickness can be adopted as the thickness of the second optical compensation layer as long as the effects of the present invention are exhibited. Specifically, the thickness is preferably 0.1 to 50 μm, more preferably 0.5 to 30 μm, and still more preferably 1 to 10 μm.

  As a material constituting the second optical compensation layer, any appropriate material can be adopted as long as the above optical characteristics can be obtained. For example, such a material includes a non-liquid crystalline material. Particularly preferred are non-liquid crystalline polymers. Unlike the liquid crystalline material, such a non-liquid crystalline material can form a film exhibiting optical uniaxiality of nx = ny> nz by its own property regardless of the orientation of the substrate. As a result, not only an oriented substrate but also an unoriented substrate can be used. Furthermore, even when an unoriented substrate is used, the step of applying an alignment film on the surface, the step of laminating the alignment film, and the like can be omitted.

  As the non-liquid crystalline material, for example, polymers such as polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide are preferable because they are excellent in heat resistance, chemical resistance, transparency, and rich in rigidity. Any one of these polymers may be used alone, or a mixture of two or more having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. . Among such polymers, polyimide is particularly preferable because of its high transparency, high orientation, and high stretchability.

  The molecular weight of the polymer is not particularly limited. For example, the weight average molecular weight (Mw) is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 2,000 to 500,000. is there.

  As the polyimide, for example, a polyimide having high in-plane orientation and soluble in an organic solvent is preferable. Specifically, for example, it includes a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and an aromatic tetracarboxylic dianhydride disclosed in JP 2000-511296 A, and has the following formula ( A polymer containing one or more repeating units shown in 1) can be used.

In the above formula (1), R ^{3 to} R ⁶ are each independently hydrogen, halogen, a phenyl group, a phenyl group substituted with ₁ to 4 halogen atoms or a C ₁ to ₁₀ alkyl group, and C _1. ~ At least one substituent selected from the group consisting of ₁₀ alkyl groups. ^Preferably, R 3 to R ⁶ are each independently, comprising halogen, phenyl group, from 1 to 4 halogen atoms or _C 1 _{~ 10} alkyl group-substituted phenyl group, and _C 1 _{~ 10} alkyl group And at least one substituent selected from the group.

In the above formula (1), Z represents a tetravalent aromatic group C ₆ ~ _20, preferably a pyromellitic group, a polycyclic aromatic group, a derivative of a polycyclic aromatic group, or, It is group represented by following formula (2).

In the above formula (2), Z ′ is, for example, a covalent bond, C (R ⁷ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, or NR ^Eight groups, and in the case of a plurality, they may be the same or different. W represents an integer from 1 to 10. Each R ⁷ is independently hydrogen or C (R ⁹ ) ₃ . R ⁸ is hydrogen, an alkyl group or a C ₆ ~ ₂₀ aryl group, the carbon atom number from 1 to about 20, for a plurality, may be different it may be respectively identical. Each R ⁹ is independently hydrogen, fluorine, or chlorine.

Examples of the polycyclic aromatic group include a tetravalent group derived from naphthalene, fluorene, benzofluorene or anthracene. Further, Examples of the substituted derivatives of the polycyclic aromatic group, for example, substituted with at least one alkyl group of C ₁ ~ _10, which is selected from the group consisting of fluorinated derivatives, and F or a halogen such as Cl And the above-mentioned polycyclic aromatic group.

  In addition, for example, a homopolymer described in JP-A-8-511812, wherein the repeating unit is represented by the following general formula (3) or (4), or the repeating unit is represented by the following general formula (5): The polyimide etc. which are shown are mentioned. In addition, the polyimide of following formula (5) is a preferable form of the homopolymer of following formula (3).

In the general formulas (3) to (5), G and G ′ are each independently, for example, a covalent bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, a C ( CX ₃ ) ₂ groups (where X is a halogen), CO group, O atom, S atom, SO ₂ group, Si (CH ₂ CH ₃ ) ₂ group, and N (CH ₃ ) group Groups selected from the group consisting of, and may be the same or different.

In the above formulas (3) and (5), L is a substituent, and d and e represent the number of substitutions. L is, for example, a halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group, and in a plurality of cases, they may be the same or different. . As said substituted phenyl group, the substituted phenyl group which has at least 1 type of substituent selected from the group which consists of a halogen, a _C1-3 alkyl group, and a _C1-3 halogenated alkyl group, for example is mentioned. Examples of the halogen include fluorine, chlorine, bromine, and iodine. d is an integer from 0 to 2, and e is an integer from 0 to 3.

  In the above formulas (3) to (5), 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 When Q is plural, they may be the same or different from each other. Examples of the halogen include fluorine, chlorine, bromine and iodine. As said substituted alkyl group, a halogenated alkyl group is mentioned, for example. Examples of the substituted aryl group include a halogenated aryl group. f is an integer from 0 to 4, g is an integer from 0 to 3, and h is an integer from 1 to 3. Further, g and h are preferably larger than 1.

In the above formula (4), R ¹⁰ and R ¹¹ are each independently a group selected from the group consisting of hydrogen, halogen, phenyl group, substituted phenyl group, alkyl group, and substituted alkyl group. Among these, R ¹⁰ and R ¹¹ are preferably each independently a halogenated alkyl group.

In the above formula (5), M ¹ and M ² are each independently, for example, a halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group. Examples of the halogen include fluorine, chlorine, bromine and iodine. Moreover, as said substituted phenyl group, the substituted phenyl group which has at least 1 type of substituent selected from the group which consists of a halogen, a _C1-3 alkyl group, and a _C1-3 halogenated alkyl group, for example is mentioned. .

  Specific examples of the polyimide represented by the above formula (3) include those represented by the following formula (6).

  Furthermore, examples of the polyimide include a copolymer obtained by appropriately copolymerizing an acid dianhydride other than the skeleton (repeating unit) as described above and a diamine.

  As said acid dianhydride, aromatic tetracarboxylic dianhydride is mentioned, for example. Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, heterocyclic aromatic tetracarboxylic dianhydride, 2 , 2′-substituted biphenyltetracarboxylic dianhydride and the like.

  Examples of the pyromellitic dianhydride include pyromellitic dianhydride, 3,6-diphenylpyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyromellitic dianhydride, 3, Examples include 6-dibromopyromellitic dianhydride and 3,6-dichloropyromellitic dianhydride. Examples of the benzophenone tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2 , 2 ′, 3,3′-benzophenone tetracarboxylic dianhydride and the like. Examples of the naphthalenetetracarboxylic dianhydride include 2,3,6,7-naphthalene-tetracarboxylic dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride, and 2,6. -Dichloro-naphthalene-1,4,5,8-tetracarboxylic dianhydride and the like. Examples of the heterocyclic aromatic tetracarboxylic dianhydride include, for example, thiophene-2,3,4,5-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride. Pyridine-2,3,5,6-tetracarboxylic dianhydride and the like. Examples of the 2,2′-substituted biphenyltetracarboxylic dianhydride include 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-dichloro. -4,4 ', 5,5'-biphenyltetracarboxylic dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride, etc. Can be mentioned.

  Other examples of the aromatic tetracarboxylic dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and bis (2,3-dicarboxyphenyl) methane dianhydride. Bis (2,5,6-trifluoro-3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3 3-hexafluoropropane dianhydride, 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4′-oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 4,4 ′ − [4,4′− Sopropylidene-di (p-phenyleneoxy)] bis (phthalic anhydride), N, N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl) Examples include diethylsilane dianhydride.

  Among these, the aromatic tetracarboxylic dianhydride is preferably 2,2′-substituted biphenyltetracarboxylic dianhydride, more preferably 2,2′-bis (trihalomethyl) -4,4. ', 5,5'-biphenyltetracarboxylic dianhydride, more preferably 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride It is.

  Examples of the diamine include aromatic diamines, and specific examples include benzene diamine, diaminobenzophenone, naphthalene diamine, heterocyclic aromatic diamine, and other aromatic diamines.

  Examples of the benzenediamine include o-, m- and p-phenylenediamine, 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 1,4-diamino-2-phenylbenzene and 1, Examples thereof include diamines selected from the group consisting of benzenediamines such as 3-diamino-4-chlorobenzene. Examples of the diaminobenzophenone include 2,2'-diaminobenzophenone and 3,3'-diaminobenzophenone. Examples of the naphthalenediamine include 1,8-diaminonaphthalene and 1,5-diaminonaphthalene. Examples of the heterocyclic aromatic diamine include 2,6-diaminopyridine, 2,4-diaminopyridine, and 2,4-diamino-S-triazine.

  In addition to the above, aromatic diamines include 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 4,4 ′-(9-fluorenylidene) -dianiline, 2,2′-bis (tri Fluoromethyl) -4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2′-dichloro-4,4′-diaminobiphenyl, 2,2 ′, 5,5 '-Tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) -1,1,1 , 3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3 -Aminophenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3 , 3-hexafluoropropane, 4,4′-diaminodiphenylthioether, 4,4′-diaminodiphenylsulfone, and the like.

  As said polyetherketone, the polyaryletherketone represented by following General formula (7) described in Unexamined-Japanese-Patent No. 2001-49110 is mentioned, for example.

  In the above formula (7), X represents a substituent, and q represents the number of substitutions. X is, for example, a halogen atom, a lower alkyl group, a halogenated alkyl group, a lower alkoxy group, or a halogenated alkoxy group, and when there are a plurality of X, they may be the same or different.

As said halogen atom, a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom are mentioned, for example, Among these, a fluorine atom is preferable. Examples of the lower alkyl group, for example, preferably an alkyl group having a linear or branched C ₁ ~ _6, more preferably a straight-chain or branched alkyl group of C ₁ ~ _4. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group are preferable, and a methyl group and an ethyl group are particularly preferable. Examples of the halogenated alkyl group include halides of the lower alkyl group such as a trifluoromethyl group. Examples of the lower alkoxy group, for example, preferably a straight chain or branched chain alkoxy group of C ₁ ~ _6, more preferably a straight chain or branched chain alkoxy group of C ₁ ~ _4. Specifically, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, and a tert-butoxy group are more preferable, and a methoxy group and an ethoxy group are particularly preferable. . Examples of the halogenated alkoxy group include halides of the lower alkoxy group such as a trifluoromethoxy group.

  In the above formula (7), q is an integer from 0 to 4. In the above formula (7), it is preferable that q = 0 and that the carbonyl group bonded to both ends of the benzene ring and the oxygen atom of the ether are present in the para position.

In the above formula (7), R ¹ is a group represented by the following formula (8), and m is an integer of 0 or 1.

  In the formula (8), X ′ represents a substituent, and is the same as X in the formula (7), for example. In the above formula (8), when there are a plurality of X ′, they may be the same or different. q ′ represents the number of substitutions of X ′, an integer from 0 to 4, and q ′ = 0 is preferable. P is an integer of 0 or 1.

In the above formula (8), ^{R 2} represents a divalent aromatic group. Examples of the divalent aromatic group include an o-, m- or p-phenylene group, or naphthalene, biphenyl, anthracene, o-, m- or p-terphenyl, phenanthrene, dibenzofuran, biphenyl ether, or And divalent groups derived from biphenylsulfone. In these divalent aromatic groups, hydrogen directly bonded to the aromatic group may be substituted with a halogen atom, a lower alkyl group or a lower alkoxy group. Among these, R ² is preferably an aromatic group selected from the group consisting of the following formulas (9) to (15).

In the above formula (7), R ¹ is preferably a group represented by the following formula (16). In the following formula (16), R ² and p are as defined in the above formula (8).

  Furthermore, in said formula (7), n represents a polymerization degree, for example, is the range of 2-5000, Preferably, it is the range of 5-500. Further, the polymerization may be composed of repeating units having the same structure, or may be composed of repeating units having different structures. In the latter case, the polymerization mode of the repeating unit may be block polymerization or random polymerization.

  Furthermore, it is preferable that the end of the polyaryl ether ketone represented by the above formula (7) is fluorine on the p-tetrafluorobenzoylene group side and a hydrogen atom on the oxyalkylene group side. For example, it can be represented by the following general formula (17). In the following formula, n represents the same degree of polymerization as in the above formula (7).

  Specific examples of the polyaryletherketone represented by the above formula (7) include those represented by the following formulas (18) to (21). In each of the following formulas, n represents the above formula (7). Represents the same degree of polymerization.

  In addition to these, examples of the polyamide or polyester include polyamides and polyesters described in JP-T-10-508048, and their repeating units are represented by the following general formula (22), for example. Can be represented.

In the above formula (22), Y is O or NH. E is, for example, a covalent bond, a C ₂ alkylene group, a halogenated C ₂ alkylene group, a CH ₂ group, a C (CX ₃ ) ₂ group (where X is a halogen or hydrogen), a CO group, At least one group selected from the group consisting of O atom, S atom, SO ₂ group, Si (R) ₂ group, and N (R) group, which may be the same or different. . In E, R is at least one of a C _1-3 alkyl group and a C _1-3 halogenated alkyl group, and is in a meta position or a para position with respect to a carbonyl functional group or a Y group.

  In the formula (22), A and A ′ are substituents, and t and z represent the number of substitutions. P is an integer from 0 to 3, q is an integer from 1 to 3, and r is an integer from 0 to 3.

A is, for example, an alkoxy group represented by hydrogen, halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, OR (where R is as defined above), An aryl group, a substituted aryl group by halogenation, etc., a C _1-9 alkoxycarbonyl group, a C _1-9 alkylcarbonyloxy group, a C _1-12 aryloxycarbonyl group, a C _1-12 arylcarbonyloxy group and substituted derivatives thereof, C _1-12 arylcarbamoyl group, and is selected from the group consisting of C _1-12 arylcarbonylamino group and a substituted derivative thereof, in the case of a plurality, may be different may be respectively identical. The above A ′ is, for example, selected from the group consisting of halogen, C _1-3 alkyl group, C _1-3 halogenated alkyl group, phenyl group and substituted phenyl group. It may be. Examples of the substituent on the phenyl ring of the substituted phenyl group include a halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, and a combination thereof. The t is an integer from 0 to 4, and the z is an integer from 0 to 3.

  Among the repeating units of polyamide or polyester represented by the above formula (22), those represented by the following general formula (23) are preferable.

  In the above formula (23), A, A ′ and Y are as defined in the above formula (22), and v is an integer of 0 to 3, preferably 0 to 2. x and y are each 0 or 1, but are not 0 at the same time.

  Next, a representative method for manufacturing the second optical compensation layer will be described. As a method for manufacturing the second optical compensation layer, any appropriate method can be adopted as long as the effects of the present invention can be obtained.

  The second optical compensation layer is preferably after applying a solution of at least one polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide to the transparent polymer film. It is formed by drying, forming the polymer layer on a transparent polymer film, and stretching or shrinking the transparent polymer film and the polymer layer together.

  The solvent of the coating solution (polymer solution to be applied to the transparent polymer film) is not particularly limited. For example, halogen such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, etc. Hydrocarbons; phenols such as phenol and parachlorophenol; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopenta Non-ketone solvents such as 2-pyrrolidone and N-methyl-2-pyrrolidone; Ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethyl Alcohol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, alcohol solvents such as 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; acetonitrile, butyronitrile Nitrile solvents such as: ether solvents such as diethyl ether, dibutyl ether, and tetrahydrofuran; carbon disulfide, ethyl cellosolve, butyl cellosolve, and the like. Of these, methyl isobutyl ketone is preferred. This is because it exhibits high solubility in non-liquid crystal materials and does not erode the substrate. These solvents may be used alone or in combination of two or more.

  As the concentration of the non-liquid crystalline polymer in the coating solution, any appropriate concentration can be adopted as long as the above optical compensation layer is obtained and coating is possible. For example, the solution preferably contains 5 to 50 parts by weight, more preferably 10 to 40 parts by weight of the non-liquid crystalline polymer with respect to 100 parts by weight of the solvent. A solution having such a concentration range has a viscosity that is easy to apply.

  The coating solution may further contain various additives such as a stabilizer, a plasticizer, and metals as necessary.

  The coating solution may further contain other different resins as necessary. Examples of such other resins include various general-purpose resins, engineering plastics, thermoplastic resins, and thermosetting resins. By using such a resin in combination, it is possible to form an optical compensation layer having appropriate mechanical strength and durability depending on the purpose.

  Examples of the general-purpose resin include polyethylene (PE), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), ABS resin, and AS resin. Examples of the engineering plastic include polyacetate (POM), polycarbonate (PC), polyamide (PA: nylon), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyethersulfone (PES), polyketone (PK), polyimide (PI), polycyclohexanedimethanol terephthalate (PCT), polyarylate (PAR), and liquid crystal polymer. (LCP) and the like. As said thermosetting resin, an epoxy resin, a phenol novolak resin, etc. are mentioned, for example.

  The kind and amount of the different resin added to the coating solution can be appropriately set according to the purpose. For example, such a resin can be added in a proportion of preferably 0 to 50% by mass, more preferably 0 to 30% by mass with respect to the non-liquid crystalline polymer.

  Examples of the coating method for the solution include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. Further, in the application, a polymer layer superposition method may be employed as necessary.

  After coating, for example, the solvent in the solution is evaporated and removed by drying such as natural drying, air drying, and heat drying (for example, 60 to 250 ° C.) to form a film-like optical compensation layer.

  As the transparent polymer film, a film similar to a protective layer described later (described in the section B-4) can be used.

  The second optical compensation layer may be used by peeling off the first optical compensation layer from the laminate obtained above (a laminate in which the first optical compensation layer is formed on the transparent polymer film). It may be good or may be used as it is. When the laminate is used as it is and further laminated with the polarizer, the transparent polymer film in the laminate may function as a protective film for the polarizer described later.

B-3. Polarizer Any appropriate polarizer may be adopted as the first polarizer and the second polarizer depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced by, for example, dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

B-4. Protective layer The protective layer 50 is preferably transparent and has no color. The in-plane retardation Δnd (550) of the protective layer 50 is preferably 0 nm or more and 10 nm or less, and more preferably 0 nm or more and 8 nm or less. The thickness direction retardation Rth (550) of the protective layer 50 is preferably 10 nm or more and 80 nm or less, more preferably 40 nm or more and 80 nm or less, and further preferably 45 nm or more and 70 nm or less.

  The thickness of the protective layer 50 can be appropriately set according to the purpose. Specifically, the thickness is preferably 20 to 140 μm, more preferably 40 to 120 μm, and still more preferably 60 to 100 μm.

  Any appropriate material can be adopted as the material constituting the protective layer 50. Examples of such materials include plastic films that are excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and the like. Specific examples of the resin constituting the plastic film include acetate resin such as triacetyl cellulose (TAC), polyester resin, polyethersulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, poly Examples include norbornene resin, cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyacrylic resin, and mixtures thereof. Also, thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins may be used. From the viewpoint of polarization characteristics and durability, a TAC film whose surface is saponified with alkali or the like is preferable.

  Furthermore, for example, a polymer film formed from a resin composition as described in JP-A-2001-343529 (WO 01/37007) can also be used for the transparent protective layer. More specifically, it is a mixture of a thermoplastic resin having a substituted imide group or an unsubstituted imide group in the side chain and a thermoplastic resin having a substituted phenyl group or an unsubstituted phenyl group and a cyano group in the side chain. Specific examples include a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. For example, an extruded product of such a resin composition can be used.

  As described above, the liquid crystal panel of the present invention may have a protective film in addition to the protective layer. As the protective film, the same film as the protective layer can be used.

  The above layers (films) are laminated through any appropriate pressure-sensitive adhesive layer or adhesive layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The measuring method of each characteristic in an Example is as follows.

(1) Retardation measurement Refractive indexes nx, ny and nz of a sample film are measured with a spectroscopic ellipsometer (manufactured by JASCO Corporation, M-220) to calculate an in-plane retardation Δnd and a thickness direction retardation Rth. did. The measurement temperature was 23 ° C., and the measurement wavelengths were 380 nm, 550 nm, and 780 nm.
(2) Measurement of photoelastic coefficient The photoelastic coefficient of the sample film was measured with a spectroscopic ellipsometer (manufactured by JASCO Corporation, M-220).
(3) Measurement of color shift Using ELDIM's product name “EZ Contrast 160D”, the color angle of the liquid crystal display device is measured by changing the polar angle from 0 ° to 80 ° in the direction of 45 ° azimuth, and XY color Plotted on the degree diagram. Furthermore, the color tone of the liquid crystal display device was measured by changing the azimuth angle from 0 ° to 360 ° in a polar angle of 60 °.
(4) Measurement of contrast A white image and a black image were displayed on a liquid crystal display device, and measurement was performed using a trade name “EZ Contrast 160D” manufactured by ELDIM.

(Formation of first optical compensation layer)
A film of cellulose ester having a thickness of 70 μm (manufactured by Kaneka, trade name: KA, DSac (acetyl substitution degree) = 0.04, DSpr (propionyl substitution degree) = 2.76) 1.5 times free at 145 ° C. The first optical compensation layer having a thickness of 68 μm was obtained by stretching. The photoelastic coefficient of the obtained first optical compensation layer was 25 × 10 ⁻¹² (m ² / N). The in-plane retardation of the obtained first optical compensation layer is Δnd (380) = 65 nm, Δnd (550) = 90 nm, Δnd (780) = 105 nm, and the thickness direction retardation is Rth (380). = 69 nm, Rth (550) = 95 nm, Rth (780) = 111 nm. The refractive index profile at 550 nm was nx> ny≈nz.

(Preparation of first polarizing plate with optical compensation layer)
The first optical compensation layer obtained above is a polarizing plate having a configuration of TAC protective film (manufactured by Fuji Photo Film, trade name: TF80UL) / polarizer / TAC protective film (trade name: TF80UL) [Nitto Denko Corporation A first polarizing plate with an optical compensation layer was obtained by pasting it on a product made by the company, trade name: SEG1224] via an adhesive (thickness 20 μm). At this time, lamination was performed such that the slow axis of the first optical compensation layer and the stretching axis (absorption axis) of the polarizer were substantially perpendicular to each other. The in-plane retardation of the TAC protective film (trade name: TF80UL) was Δnd (550) = 1 nm, and the retardation in the thickness direction was Rth (550) = 60 nm.

(Formation of second optical compensation layer)
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 15% by mass polyimide solution. This solution was applied to a triacetyl cellulose substrate (transparent polymer film) with a thickness of 30 μm. Thereafter, a second optical compensation layer having a thickness of about 4 μm was obtained by drying at 100 ° C. for 10 minutes. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 0.4 nm, Δnd (550) = 0.3 nm, Δnd (780) = 0.3 nm, and the retardation in the thickness direction Were Rth (380) = 178 nm, Rth (550) = 120 nm, and Rth (780) = 110 nm. The refractive index profile at 550 nm was nx≈ny> nz.

(Production of second polarizing plate with optical compensation layer)
The second optical compensation layer obtained above was attached to a polarizing plate [manufactured by Nitto Denko Corporation, trade name: SEG1224] via an adhesive (thickness 20 μm), and the second optical compensation layer-attached polarizing plate Got.

(Production of liquid crystal panel)
Remove the liquid crystal cell from Sony's Happy Vega 32-inch LCD TV (with VA mode liquid crystal cell), and paste the first polarizing plate with the optical compensation layer on the viewing side of the liquid crystal cell with an adhesive (thickness 20 μm). I attached. At that time, the first optical compensation layer was attached so as to be on the liquid crystal cell side. The second polarizing plate with an optical compensation layer was attached to the backlight side of the liquid crystal cell via an adhesive (thickness: 20 μm). At that time, the second optical compensation layer was attached so as to be on the liquid crystal cell side. Further, the polarizer is stretched (absorption) axis of the polarizing plate with the first optical compensation layer and the polarizer has a stretching (absorption) axis of the polarizing plate with the second optical compensation layer so as to be substantially orthogonal to each other. A liquid crystal panel was obtained. FIG. 5A shows the measurement result of the color shift of the liquid crystal display device manufactured using the obtained liquid crystal panel when the polar angle is changed from 0 ° to 80 ° in the azimuth angle of 45 °. FIG. 5B shows the measurement result of the color shift when the azimuth angle is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Formation of first optical compensation layer)
A film of cellulose ester having a thickness of 70 μm (manufactured by Kaneka, trade name: KA) was subjected to free end stretching at 145 ° C. by 1.45 times to obtain a first optical compensation layer. The photoelastic coefficient of the obtained first optical compensation layer was 25 × 10 ⁻¹² (m ² / N). The in-plane retardation of the obtained first optical compensation layer is Δnd (380) = 58 nm, Δnd (550) = 80 nm, Δnd (780) = 93 nm, and the thickness direction retardation is Rth (380). = 65 nm, Rth (550) = 90 nm, Rth (780) = 105 nm. The refractive index profile at 550 nm was nx> ny≈nz.

(Formation of second optical compensation layer)
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 15% by mass polyimide solution. This solution was applied to a triacetyl cellulose substrate (transparent polymer film) with a thickness of 30 μm. Thereafter, a second optical compensation layer having a thickness of about 5 μm was obtained by drying at 100 ° C. for 10 minutes. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 0.3 nm, Δnd (550) = 0.2 nm, Δnd (780) = 0.2 nm, and the retardation in the thickness direction Rth (380) = 208 nm, Rth (550) = 140 nm, Rth (780) = 129 nm. The refractive index profile at 550 nm was nx≈ny> nz.

  A liquid crystal panel was obtained in the same manner as in Example 1 except that the first optical compensation layer and the second optical compensation layer obtained above were used. FIG. 6A shows the measurement result of the color shift when the polar angle is changed from 0 ° to 80 ° in the azimuth angle 45 ° direction of the liquid crystal display device manufactured using the obtained liquid crystal panel. FIG. 6B shows the measurement result of the color shift when the azimuth is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Formation of first optical compensation layer)
A film of cellulose ester having a thickness of 70 μm (manufactured by Kaneka, trade name: KA) was stretched freely at 145 ° C. by 1.55 times to obtain a first optical compensation layer. The photoelastic coefficient of the obtained first optical compensation layer was 25 × 10 ⁻¹² (m ² / N). The in-plane retardation of the obtained first optical compensation layer is Δnd (380) = 73 nm, Δnd (550) = 100 nm, Δnd (780) = 117 nm, and the thickness direction retardation is Rth (380). = 76 nm, Rth (550) = 105 nm, Rth (780) = 123 nm. The refractive index profile at 550 nm was nx> ny≈nz.

(Formation of second optical compensation layer)
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 15% by mass polyimide solution. This solution was applied to a triacetyl cellulose substrate (transparent polymer film) with a thickness of 30 μm. Thereafter, a second optical compensation layer having a thickness of about 4 μm was obtained by drying at 100 ° C. for 10 minutes. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 0.3 nm, Δnd (550) = 0.2 nm, Δnd (780) = 0.2 nm, and the retardation in the thickness direction Were Rth (380) = 164 nm, Rth (550) = 110 nm, and Rth (780) = 101 nm. The refractive index profile at 550 nm was nx≈ny> nz.

  A liquid crystal panel was obtained in the same manner as in Example 1 except that the first optical compensation layer and the second optical compensation layer obtained above were used. FIG. 7A shows the measurement result of the color shift when the polar angle is changed from 0 ° to 80 ° in the azimuth angle 45 ° direction of the liquid crystal display device manufactured using the obtained liquid crystal panel. FIG. 7B shows the measurement result of the color shift when the azimuth angle is changed from 0 ° to 360 ° in the direction of 60 °. In addition, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Formation of first optical compensation layer)
A film of cellulose ester having a thickness of 70 μm (manufactured by Kaneka Co., Ltd., trade name: KA) was stretched at 150 ° C. by 1.5 times to obtain a first optical compensation layer. The photoelastic coefficient of the obtained first optical compensation layer was 25 × 10 ⁻¹² (m ² / N). The in-plane retardation of the obtained first optical compensation layer is Δnd (380) = 65 nm, Δnd (550) = 90 nm, Δnd (780) = 105 nm, and the thickness direction retardation is Rth (380). = 80 nm, Rth (550) = 110 nm, Rth (780) = 128 nm. The refractive index distribution at 550 nm was nx>ny> nz.

(Formation of second optical compensation layer)
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 15% by mass polyimide solution. This solution was applied to a triacetyl cellulose substrate (transparent polymer film) with a thickness of 25 μm. Thereafter, a second optical compensation layer having a thickness of about 3.5 μm was obtained by drying at 100 ° C. for 10 minutes. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 0.4 nm, Δnd (550) = 0.3 nm, Δnd (780) = 0.3 nm, and the retardation in the thickness direction Were Rth (380) = 149 nm, Rth (550) = 100 nm, and Rth (780) = 92 nm. The refractive index profile at 550 nm was nx≈ny> nz.

(Preparation of first polarizing plate with optical compensation layer)
The first optical compensation layer obtained above was attached to a polarizing plate [manufactured by Nitto Denko Corporation, trade name: SEG1224] via an adhesive (thickness 20 μm). At this time, lamination was performed such that the slow axis of the first optical compensation layer and the stretching axis (absorption axis) of the polarizer were substantially perpendicular to each other. Subsequently, the 2nd optical compensation layer obtained above was affixed on the said 1st optical compensation layer via an adhesive (thickness 20 micrometers), and the 1st polarizing plate with an optical compensation layer was obtained.

(Production of liquid crystal panel)
The said 1st polarizing plate with an optical compensation layer was affixed on the visual recognition side of the liquid crystal cell similar to the liquid crystal cell used in Example 1 through the adhesive agent (thickness 20 micrometers). At that time, the second optical compensation layer was attached so as to be on the liquid crystal cell side. On the backlight side of the liquid crystal cell, a polarizing plate [manufactured by Nitto Denko Corporation, trade name: SEG1224] was attached via an adhesive (thickness 20 μm). Further, the polarizer (extension) axis of the polarizing plate with the first optical compensation layer and the extension (absorption) axis of the polarizer of the polarizing plate are laminated so as to be substantially orthogonal to each other to obtain a liquid crystal panel. It was. FIG. 8A shows the measurement result of the color shift of the liquid crystal display device produced using the obtained liquid crystal panel when the polar angle is changed from 0 ° to 80 ° in the azimuth angle of 45 °. FIG. 8B shows the measurement result of the color shift when the azimuth angle is changed from 0 ° to 360 ° in the angle 60 ° direction. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Formation of first optical compensation layer)
A film of cellulose ester having a thickness of 110 μm [manufactured by Kaneka Co., Ltd., trade name: KA] was stretched at 150 ° C. by 1.5 times to obtain a first optical compensation layer. The photoelastic coefficient of the obtained first optical compensation layer was 25 × 10 ⁻¹² (m ² / N). The in-plane retardation of the obtained first optical compensation layer is Δnd (380) = 94 nm, Δnd (550) = 130 nm, Δnd (780) = 152 nm, and the thickness direction retardation is Rth (380). = 105 nm, Rth (550) = 145 nm, Rth (780) = 169 nm. The refractive index distribution at 550 nm was nx>ny> nz.

(Preparation of first polarizing plate with optical compensation layer)
The polyvinyl alcohol film was dyed in an aqueous solution containing iodine and then uniaxially stretched 6 times between rolls having different speed ratios in an aqueous solution containing boric acid to obtain a polarizer. The first optical compensation layer was attached to one side of the polarizer thus obtained via an adhesive (thickness: 0.1 μm). At this time, lamination was performed such that the slow axis of the first optical compensation layer and the stretching axis (absorption axis) of the polarizer were substantially perpendicular to each other. Further, a commercially available TAC protective film (thickness: 80 μm) [manufactured by Fuji Photo Film, trade name: TF80UL] is attached to the other side of the polarizer via a polyvinyl alcohol adhesive (thickness: 0.1 μm). A polarizing plate with an optical compensation layer was obtained.

(Formation of second optical compensation layer)
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 15% by mass polyimide solution. This solution was applied to a triacetylcellulose substrate (transparent polymer film) with a thickness of 30 μm. Thereafter, a second optical compensation layer having a thickness of about 4.2 μm was obtained by drying at 100 ° C. for 10 minutes. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 0.3 nm, Δnd (550) = 0.3 nm, Δnd (780) = 0.2 nm, and the retardation in the thickness direction Rth (380) = 208 nm, Rth (550) = 140 nm, Rth (780) = 129 nm. The refractive index profile at 550 nm was nx≈ny> nz.

  A liquid crystal panel was obtained in the same manner as in Example 1 except that the first polarizing plate with an optical compensation layer and the second optical compensation layer obtained above were used. FIG. 9A shows the measurement result of the color shift of the liquid crystal display device manufactured using the obtained liquid crystal panel when the polar angle is changed from 0 ° to 80 ° in the azimuth angle of 45 °. FIG. 9B shows the measurement result of the color shift when the azimuth angle is changed from 0 ° to 360 ° in the direction of 60 °. Also, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Comparative Example 1)
In the formation of the second optical compensation layer, a polyimide solution was applied to the triacetyl cellulose base material, then dried at 100 ° C. for 10 minutes, and stretched 1.2 times at 155 ° C. to form the second optical compensation layer. A liquid crystal panel was obtained in the same manner as in Example 1 except that the first optical compensation layer was not used. The refractive index distribution at 550 nm of the obtained second optical compensation layer was nx>ny> nz. FIG. 10 (a) shows the measurement result of the color shift when the polar angle is changed from 0 ° to 80 ° in the azimuth angle 45 ° direction of the liquid crystal display device manufactured using the obtained liquid crystal panel. FIG. 10B shows the measurement result of the color shift when the azimuth is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Comparative Example 2)
A norbornene-based resin film [manufactured by Nippon Zeon, trade name: ZEONOR ZF14-100] is stretched 1.25 times in the X-axis direction and 1.03 times in the Y-axis direction at 135 ° C. as a second optical compensation layer. Using. The in-plane retardation of the obtained second optical compensation layer is Δnd (380) = 75 nm, Δnd (550) = 68 nm, Δnd (780) = 67 nm, and the thickness direction retardation is Rth (380). = 188 nm, Rth (550) = 170 nm, Rth (780) = 168 nm. The refractive index distribution at 550 nm was nx>ny> nz. The obtained second optical compensation layer was attached to a polarizing plate [manufactured by Nitto Denko Corporation, trade name: SEG1224] via an adhesive (thickness 20 μm) to obtain a second polarizing plate with an optical compensation layer. It was.

  A polarizing plate (manufactured by Nitto Denko Corporation, trade name: SEG1224) was attached to the viewing side of the liquid crystal cell similar to the liquid crystal cell used in Example 1 via an adhesive (thickness 20 μm). On the backlight side of the liquid crystal cell, the above-obtained second polarizing plate with an optical compensation layer was attached via an adhesive (thickness 20 μm). At that time, the second optical compensation layer was attached so as to be on the liquid crystal cell side. In addition, the polarizers sandwiching the liquid crystal cell were laminated so that the stretch (absorption) axes thereof were substantially orthogonal to each other to obtain a liquid crystal panel. FIG. 11 (a) shows the measurement result of the color shift when the polar angle is changed from 0 ° to 80 ° in the azimuth angle 45 ° direction of the liquid crystal display device manufactured using the obtained liquid crystal panel. FIG. 11B shows the measurement result of the color shift when the azimuth is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Comparative Example 3)
A liquid crystal panel was obtained in the same manner as in Example 1 except that a cellulose resin film [manufactured by Konica Minolta, trade name: KC8NYACS] was used as the first optical compensation layer and the second optical compensation layer. The in-plane retardation of the cellulose-based resin film is Δnd (380) = 37 nm, Δnd (550) = 45 nm, Δnd (780) = 49 nm, and the thickness direction retardation is Rth (380) = 120 nm. Rth (550) = 145 nm and Rth (780) = 157 nm. The refractive index distribution at 550 nm was nx>ny> nz. FIG. 12 (a) shows the measurement result of the color shift when the polar angle is changed from 0 ° to 80 ° in the azimuth angle 45 ° direction of the liquid crystal display device manufactured using the obtained liquid crystal panel. FIG. 12B shows the measurement result of the color shift when the azimuth is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

(Comparative Example 4)
A polycarbonate resin film [manufactured by Teijin, trade name: Pure Ace] was used as the first optical compensation layer. The polycarbonate resin film has a photoelastic coefficient of 61 × 10 ⁻¹² (m ² / N), and the in-plane retardation is Δnd (380) = 101 nm, Δnd (550) = 145 nm, Δnd (780) = The thickness direction retardation was Rth (380) = 99 nm, Rth (550) = 141 nm, and Rth (780) = 149 nm. The refractive index profile at 550 nm was nx> ny≈nz.

  A norbornene-based resin film [manufactured by JSR, trade name: ARTON] was biaxially stretched 1.3 times in length and width at 175 ° C. and used as the second optical compensation layer. The in-plane retardation of the second optical compensation layer is Δnd (380) = 2 nm, Δnd (550) = 2 nm, Δnd (780) = 2 nm, and the thickness direction retardation is Rth (380) = 244 nm. , Rth (550) = 220 nm and Rth (780) = 218 nm. The refractive index profile at 550 nm was nx≈ny> nz.

  A liquid crystal panel was obtained in the same manner as in Example 1 except that the first optical compensation layer and the second optical compensation layer were used. FIG. 13A shows the measurement result of the color shift of the liquid crystal display device manufactured using the obtained liquid crystal panel when the polar angle is changed from 0 ° to 80 ° in the azimuth angle of 45 °. FIG. 13B shows the measurement result of the color shift when the azimuth angle is changed from 0 ° to 360 ° in the direction of 60 °. Further, the viewing angle dependence of contrast is shown in the radar chart of FIG.

  As is apparent from FIGS. 5 to 13, the liquid crystal panels obtained in Examples 1 to 5 are superior in color shift compared to the liquid crystal panels obtained in Comparative Examples 1 to 4.

  As is apparent from FIGS. 5 to 13, it can be seen that the liquid crystal display device of the example of the present invention is superior in both front contrast and oblique contrast as compared with the liquid crystal display device of the comparative example.

  A liquid crystal display device was manufactured using the liquid crystal panels of Example 1 and Comparative Example 4, and it was observed whether display unevenness occurred during black image display. The observation photograph is shown in FIG. As shown in FIG. 14A, in the liquid crystal display device of Example 1, display unevenness was satisfactorily suppressed. On the other hand, as shown in FIG. 14B, in the liquid crystal display device of Comparative Example 4, unevenness (light leakage in some places) occurred on the entire screen. As is apparent from the photograph of FIG. 14, the liquid crystal display device of the present invention was much less bluish than the liquid crystal display device of the comparative example.

  The liquid crystal panel and the liquid crystal display device of the present invention can be suitably applied to a liquid crystal television, a mobile phone and the like.

It is a schematic sectional drawing of the liquid crystal panel by preferable embodiment of this invention. It is a schematic sectional drawing of the liquid crystal panel by another preferable embodiment of this invention. When the liquid crystal display device of this invention employ | adopts a VA mode liquid crystal cell, it is a schematic sectional drawing explaining the orientation state of the liquid crystal molecule of a liquid crystal layer. When the liquid crystal display device of this invention employ | adopts the liquid crystal cell of OCB mode, it is a schematic sectional drawing explaining the orientation state of the liquid crystal molecule of a liquid crystal layer. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of Example 1 of this invention, (c) is the radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 1 of this invention. It is. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of Example 2 of this invention, (c) is the radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 2 of this invention It is. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of Example 3 of this invention, (c) is the radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 3 of this invention It is. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of Example 4 of this invention, (c) is the radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 4 of this invention It is. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of Example 5 of this invention, (c) is the radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of Example 5 of this invention It is. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of the comparative example 1, (c) is a radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of the comparative example 1. FIG. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of the comparative example 2, (c) is a radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of the comparative example 2. FIG. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of the comparative example 3, (c) is a radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of the comparative example 3. (A) And (b) is the measurement result of the color shift of the liquid crystal panel of the comparative example 4, (c) is a radar chart which shows the viewing angle dependence of the contrast of the liquid crystal panel of the comparative example 4. (A) is the observation photograph at the time of the black image display of the liquid crystal display device of Example 1 of this invention, (b) is the observation photograph at the time of the black image display of the liquid crystal display device of the comparative example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 20 1st polarizer 20 '2nd polarizer 30 1st optical compensation layer 40 2nd optical compensation layer 50 Protective layer 11, 11' Substrate 12 Liquid crystal layer 100 Liquid crystal panel

Claims (11)

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 first polarizer and the second And at least two optical compensation layers including a first optical compensation layer and a second optical compensation layer disposed between the polarizer and the polarizer,
The first optical compensation layer has an absolute value of a photoelastic coefficient of 40 × 10 ⁻¹² (m ² / N) or less, and has a relationship of the following formulas (1) and (2):
The liquid crystal panel in which the second optical compensation layer has the relationship of the following formulas (3) and (4):
Δnd (380) <Δnd (550) <Δnd (780) (1)
nx> ny ≧ nz (2)
Rth (380)> Rth (550)> Rth (780) (3)
nx = ny> nz (4)
Here, Δnd (380), Δnd (550), and Δnd (780) represent in-plane phase differences measured at wavelengths of 380 nm, 550 nm, and 780 nm at 23 ° C., respectively, and Rth (380), Rth (550) And Rth (780) represent thickness direction retardation measured at 23 ° C. at wavelengths of 380 nm, 550 nm, and 780 nm, respectively, and nx, ny, and nz represent the slow axis direction, the fast axis direction, and the thickness direction, respectively. Represents the refractive index.   2. The liquid crystal panel according to claim 1, wherein the first optical compensation layer has a relationship of Δnd (780) / Δnd (550)> 1.10.   The liquid crystal panel according to claim 1, wherein the first optical compensation layer contains a cellulosic material.   The degree of acetyl substitution (DSac) and propionyl substitution (DSpr) of the cellulosic material is 2.0 ≦ DSac + DSpr ≦ 3.0, and 1.0 ≦ DSpr ≦ 3.0. LCD panel.   5. The liquid crystal panel according to claim 1, wherein the second optical compensation layer has a relationship of Rth (780) / Rth (550) <0.95.   2. The material constituting the second optical compensation layer is at least one non-liquid crystalline polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide. 6. The liquid crystal panel according to any one of 5 to 5.   The liquid crystal panel according to claim 1, wherein the first optical compensation layer and the second optical compensation layer are arranged on different sides with respect to the liquid crystal cell.   The first optical compensation layer has a relationship of 90 nm ≦ Δnd (550) ≦ 200 nm and functions as a protective layer on the liquid crystal cell side of the first polarizer or the second polarizer. The liquid crystal panel according to any one of 1 to 7. The liquid crystal cell side of the first polarizer or the second polarizer further has a protective layer having the relationship of the following formulas (5) and (6), and the first layer is disposed on the liquid crystal cell side of the protective layer. The liquid crystal panel according to claim 1, wherein an optical compensation layer is disposed, and the first optical compensation layer has a relationship of 50 nm ≦ Δnd (550) ≦ 150 nm:
0 nm ≦ Δnd (550) ≦ 10 nm (5)
40 nm ≦ Rth (550) ≦ 80 nm (6).   The liquid crystal panel according to claim 1, wherein the liquid crystal cell is in a VA mode or an OCB mode.   A liquid crystal display device comprising the liquid crystal panel according to claim 1.