WO2008065899A1

WO2008065899A1 - Liquid crystal panel and liquid crystal display device

Info

Publication number: WO2008065899A1
Application number: PCT/JP2007/072176
Authority: WO
Inventors: Kentarou Takeda; Junichi Nagase
Original assignee: Nitto Denko Corporation
Priority date: 2006-11-27
Filing date: 2007-11-15
Publication date: 2008-06-05

Abstract

It is an object to provide a liquid crystal panel and a liquid crystal display device that contribute miniaturization, realize a high contrast with improvement in a viewing angle characteristic, suppress a color shift and can well prevent light leakage at a black display. The liquid crystal panel is comprised of a liquid crystal cell, first through fourth optical compensation layers and first and second polarizers. The first optical compensation layer disposed on one side of the liquid crystal cell has the following relationships: Nz = 1-2.5 and Re1 (380) < Re1 (550) < Re1 (780) and the second optical compensation layer has the following relationships: nx = ny > nz and Re2(380) > Re2 (550) > Re2 (780). The third optical compensation layer disposed on the other side of the liquid crystal cell has the following relationships: Nz = 1-2.5 and Re3 (380) < Re3 (550) < Re3 (780) and the first optical compensation layer has the following relationships: nx = ny > nz and Re4 (380) > Re4 (550) > Re4 (780). The first and second optical compensation layers and the third and fourth optical compensation layers are symmetrical in position with respect to the liquid crystal cell.

Description

Specification

Liquid crystal panel and liquid crystal display device

Technical field

The present invention relates to a liquid crystal panel and a liquid crystal display device having the liquid crystal panel.

Background art

In a vertical alignment mode liquid crystal display device, light from a knock light is turned on and off for each pixel by utilizing birefringence and polarization of liquid crystal. In such a liquid crystal display device, since the liquid crystal molecules are vertically aligned when no voltage is applied, the polarizing plates arranged on both sides of the liquid crystal cell are placed so that the absorption axes of the polarizers are orthogonal to each other. Therefore, black can be displayed. In the case of white display, the liquid crystal is tilted by applying a voltage to the absorption axis direction of the polarizer and 45 °, 135 °, 225 °, and 315 ° directions, respectively. It becomes linearly polarized light in a direction rotated exactly 90 °, allowing light to pass through and displaying white. However, this is only possible when the screen is viewed from the front. In the case of black display, when viewing the screen from an oblique direction, for example, when viewing the screen from a direction of 45 ° with the absorption axis of the polarizer of the polarizer, the liquid crystal is not oriented vertically but oriented obliquely. appear. For this reason, the polarization state of the light in this direction changes due to the birefringence of the liquid crystal, and the light cannot be completely absorbed by the polarizing plate. As a result, light leakage occurs.

[0003] In addition, the polarizing plate is installed so that the absorption axes of the polarizers are orthogonal to each other. As the viewing angle is tilted in an oblique direction, the absorption axis apparently deviates from orthogonal. As a result, light leakage occurs.

For this reason, an optical compensator that compensates for the birefringence of the liquid crystal and the axial misalignment of the polarizer of the polarizing plate, for example, a biaxial retardation plate is used in the liquid crystal display device in the vertical alignment mode (for example, (See Patent Document 1).

[0005] However, if the optical compensator used is for light of a specific wavelength, compensation for light of all wavelengths emitted from the backlight is not sufficient, so light leakage at a certain wavelength is not possible. Happens. In addition, since the transmittance varies depending on the wavelength, a phenomenon in which the color appears to change when the viewing angle is changed, a so-called color shift occurs. Low these phenomena In order to reduce, it is required to compensate the wavelength of visible light over the entire area.

[0006] In response to the above request, negative thickness direction retardation having positive refractive index wavelength dispersion (positive dispersion)

It is disclosed that compensation is performed using a compensation layer having (nx = ny> nz) and a retardation plate having negative refractive index wavelength dispersion (reverse dispersion) that compensates for the axial misalignment of the polarizer of the polarizing plate. Terreru (Patent Literature 2). However, in this technique, suppression of light leakage or color shift is not sufficient. In addition, the liquid crystal panel of Patent Document 2 has a large level of unevenness due to bonding, and a level that can withstand practical use cannot be obtained.

Patent Document 1: Japanese Patent Laid-Open No. 2003-270442

Patent Document 2: Patent No. 3648240

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention has been made to solve the above-described conventional problems, contributes to thinning, improves viewing angle characteristics, achieves high contrast, suppresses color shift, and displays black. It would be interesting to provide a liquid crystal panel and a liquid crystal display device that can prevent light leakage in the well.

Means for solving the problem

[0008] The liquid crystal panel of the present invention has a relationship between a liquid crystal cell having a liquid crystal layer containing liquid crystal molecules vertically aligned when no voltage is applied, and Nz = l to 2.5 disposed on one side of the liquid crystal cell. A first optical compensation layer having a relationship of Re (380) and Re (550) and Re (780), and a relationship of nx = ny> nz, and Re (380)> Re (550)> Second light with Re (780) relationship

2 2 2

An academic compensation layer, a first polarizer,

The liquid crystal cell is placed on the other side of the liquid crystal cell and has a relationship of Νζ = 1 to 2.5, and Re (380) <

3 3

A third optical compensation layer having a relationship of (550) <Re (780) and a relationship of nx = ny> nz

Three

, Re (380)> Re (550)> Re (780)

4 4 4

Having a polarizer,

The first optical compensation layer and the second optical compensation layer, the third optical compensation layer and the fourth optical compensation layer are arranged in a symmetrical positional relationship with respect to the liquid crystal cell. ! /

[0009] Preferable! /, In the embodiment! / This is because the liquid crystal cell is placed on one side of the liquid crystal cell. In order, the first optical compensation layer, the second optical compensation layer, and the first polarizer are arranged, and the third liquid crystal cell is arranged in this order from the liquid crystal cell on the other side of the liquid crystal cell. The optical compensation layer, the fourth optical compensation layer, and the second polarizer are disposed.

[0010] Preferable! /, In the embodiment! /, In order from the liquid crystal cell on one side of the liquid crystal cell, the second optical compensation layer and the first optical compensation layer in this order. The first polarizer is disposed, and the fourth optical compensation layer, the third optical compensation layer, and the second optical device are arranged in this order from the liquid crystal cell on the other side of the liquid crystal cell. The polarizer is arranged.

In a preferred embodiment, the first optical compensation layer and the third optical compensation layer have a photoelastic coefficient of 70 X 10 — ¹² (m ² / N) or less.

[0012] In a preferred embodiment, the first optical compensation layer and the third optical compensation layer include

, Re (780) / Re (550)> 1.1.

[0013] In a preferred embodiment, the first optical compensation layer and the third optical compensation layer include

Formed from cellulosic materials or polyester materials!

In a preferred embodiment, the first optical compensation layer and the third optical compensation layer are

V, formed from a material having a non-aromatic cyclic structure and an ester group.

[0015] In a preferred embodiment, the second optical compensation layer and the fourth optical compensation layer include

Re (780) / Re (550) <0 · 95.

In a preferred embodiment, the thickness direction retardation Rth of the second optical compensation layer and the fourth optical compensation layer is 20 nm or more.

[0017] In a preferred embodiment, the first optical compensation layer and the third optical compensation layer are polymer films stretched in the width direction.

[0018] According to still another aspect of the present invention, a liquid crystal display device is provided. The liquid crystal display device includes the liquid crystal panel.

The invention's effect

According to the present invention, a liquid crystal panel that contributes to thinning, improves viewing angle characteristics, realizes high contrast, suppresses color shift, and can favorably prevent light leakage in black display, and A liquid crystal display device may be provided.

[0020] Such an effect has a predetermined positional relationship on one side of the liquid crystal cell, and a relationship of Nz = l to 2.5. A first optical compensation layer having a relationship of (380) <R ^ (550) <R ^ (780) and a relationship of nx = ny> nz, and Re (380)> Re ( 550)> Re (780)

2 2 2

A second optical compensation layer and a first polarizer are disposed, and have a relationship of Nz = l to 2.5 in a predetermined positional relationship on the other side of the liquid crystal cell, and Re (380) Re (550) Ku Re (780)

The third optical compensation layer having the relationship 3 3 3 and the relationship nx = ny> nz, and Re (380)> Re (5

4 4

50)> Re (780) and the fourth optical compensation layer and the second polarizer are arranged.

Four

It can be expressed by a liquid crystal panel.

Brief Description of Drawings

FIG. 1 is a schematic sectional view of a liquid crystal panel according to a preferred embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in a liquid crystal layer in a VA mode liquid crystal cell.

FIG. 3 (A) is a graph showing refractive index wavelength dispersion characteristics of the first optical compensation layer and the second optical compensation layer obtained in Example 1. (B) is a graph showing the refractive index wavelength dispersion characteristics of the norbornene-based resin film used in Comparative Example 4. (C) shows the refractive index wavelength dispersion characteristics of the first optical compensation layer used in Example 6 and the first optical compensation layer used in Example 1.

FIG. 4 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Example 1, and a graph (c) showing the relationship between X value and y value and azimuth angle. .

FIG. 5 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Example 2, and a graph (c) showing the relationship between X and y values and azimuth. .

FIG. 6 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Example 3, and a graph (c) showing the relationship between X value and y value and azimuth angle. .

FIG. 7 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Example 4, and a graph (c) showing the relationship between X value and y value and azimuth angle. .

FIG. 8 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Example 5, and a graph (c) showing the relationship between X value, y value and azimuth angle. .

FIG. 9 is a contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 1, and a graph (c) showing the relationship between X and y values and azimuth. . 10] Contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 2, and graph (c) showing the relationship between the X and y values and the azimuth.

11] A contrast contour map (a), an xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 3, and a graph (c) showing the relationship between the X and y values and the azimuth.

12] A contrast contour diagram (a), an xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 4, and a graph (c) showing the relationship between the X and y values and the azimuth.

13] A contrast contour map (a), an xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 5, and a graph (c) showing the relationship between the X and y values and the azimuth angle.

14] Contrast contour map (a), xy chromaticity diagram (b) of the liquid crystal display device obtained in Comparative Example 6, and graph (c) showing the relationship between X value and y value and azimuth.

15] A contrast contour map (a) of the liquid crystal display device obtained in Comparative Example 7 and a graph (b) showing the relationship between the X and y values and the azimuth.

16] A contrast contour map (a) of the liquid crystal display device obtained in Comparative Example 8 and a graph (b) showing the relationship between the X and y values and the azimuth.

FIG. 17 is an enlarged photograph of the screen during black display in the liquid crystal display device (a) produced in Example 1 and the liquid crystal display device (b) produced in Comparative Example 6.

Explanation of symbols

10 仪

11 First optical compensation layer

12 Third optical compensation layer

21 Second optical compensation layer

22 Fourth optical compensation layer

31 First polarizer

32 Second polarizer

100 LCD panel

BEST MODE FOR CARRYING OUT THE INVENTION

(Definition of terms and symbols)

Definitions of terms and symbols used herein are as follows: (1) “nx” is the refractive index in the direction that maximizes the in-plane refractive index (ie, slow axis direction), and “ny” is the direction that is perpendicular to the slow axis in the plane (ie, fast phase). (Axial 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 strictly 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 have a practical effect on the overall polarization characteristics of the liquid crystal panel. Similarly, for example, “ny = nz” includes not only the case where ny and nz are exactly equal, but also the case where ny and nz are substantially equal.

(2) “In-plane retardation Re” means the retardation value in the film (layer) plane measured with light at a wavelength of 590 nm at 23 ° C unless otherwise specified. Re is the formula when the refractive index in the slow axis direction and the fast axis direction of the film (layer) at a wavelength of 590 nm is nx and ny, respectively, and d (nm) is the thickness of the film (layer): Re = (nx—ny) X d Also, Re () is

The retardation value in the plane of the film (layer) measured with light of wavelength nm at 23 ° C.

(3) “Thickness direction retardation Rth” means a thickness direction retardation value measured at 23 ° C. with light having a wavelength of 590 nm unless otherwise specified. Rth is the formula: Rth = (nx) where the refractive index in the slow axis direction and thickness direction of the film (layer) at a wavelength of 590 nm is nx and nz, respectively, and d (nm) is the thickness of the film (layer). — Nz) Calculated by Xd.

(4) The subscripts “1” to “4” attached to the terms and symbols described in this specification represent the first to fourth optical compensation layers, respectively.

(5) Nz coefficient

The Nz coefficient is obtained from the following equation (1).

Nz = (.nx—nz) / (nx—ny) (1)

液晶 .LCD panel

A— 1. Overall configuration of LCD panel

The liquid crystal panel of the present invention includes a liquid crystal cell, a first optical compensation layer disposed on one side of the liquid crystal cell, a second optical compensation layer, a first polarizer, and the other of the liquid crystal cell. A third optical compensation layer, a fourth optical compensation layer, and a second polarizer disposed on the first side, the first optical compensation layer and the second optical compensation layer, The third optical compensation layer and the fourth optical compensation layer are arranged in a symmetrical positional relationship with respect to the liquid crystal cell. FIG. 1 (a) is a schematic cross-sectional view of a liquid crystal panel according to one preferred embodiment of the present invention. As shown in FIG. 1 (a), the liquid crystal node 100 includes a liquid crystal cell 10 and a first optical compensation layer 11 and a second liquid crystal layer 10 arranged in this order from the liquid crystal cell side on one side of the liquid crystal cell 10. Optical compensation layer 21 and first polarizer 31, and third optical compensation layer 12, fourth optical compensation layer 22, and the other arranged on the other side of liquid crystal cell 10 in this order from the liquid crystal cell side. And a second polarizer 3 2. FIG. 1 (b) is a schematic cross-sectional view of a liquid crystal panel according to another preferred embodiment of the present invention. As shown in FIG. 1 (b), the liquid crystal panel 100 includes a liquid crystal cell 10 and a second optical compensation layer 21, a first liquid crystal cell 10 arranged in this order from the liquid crystal cell side on one side of the liquid crystal cell 10. The optical compensation layer 11 and the first polarizer 31, and the fourth optical compensation layer 22 and the third optical compensation layer 12 arranged in this order from the liquid crystal sensor side to the other side of the liquid crystal cell 10. And a second polarizer 32.

[0026] The first optical compensation layer 11 and the third optical compensation layer 12 have a relationship of Νζ = 1 to 2.5, respectively, and Re (380) Re Re (550) Re Re (780) Have a relationship. Second

1 (3) 1 (3) 1 (3)

In the optical compensation layer 21 and the fourth optical compensation layer 22, the refractive index ellipsoid has a relationship of nx = ny> nz, and the relationship of Re (380)> Re (550)> Re (780) Have.

2 (4) 2 (4) 2 (4)

[0027] As described above, the optical compensation layers having a predetermined birefringence are arranged symmetrically with the liquid crystal cell in between, so that when the liquid crystal cell is viewed from an oblique direction, the polarizers above and below the liquid crystal cell Optical defects (for example, coloring) due to deviation of the formed angle from crossed Nicols (90 °) can be compensated uniformly above and below the liquid crystal cell. As a result, the viewing angle characteristics of the liquid crystal panel are improved, a high contrast is realized, the color shift is suppressed, and light leakage in black display can be prevented well.

In the liquid crystal panel 100 shown in FIG. 1, the first polarizer 31 and the second polarizer 32 are arranged so that their absorption axes are substantially orthogonal to each other. Further, the first polarizer 31 is arranged so that the absorption axis thereof is substantially orthogonal to the slow axis of the first optical compensation layer 11. The second polarizer 32 is arranged such that its absorption axis is substantially perpendicular to the slow axis of the third optical compensation layer 12. In the present specification, “substantially orthogonal” includes a case of 90 ° ± 3.0 °, preferably 90 ° ± 1.0 °, more preferably 90 ° ± 0.5 °. It is. [0029] Although not shown, each layer of the liquid crystal panel may be disposed via any appropriate pressure-sensitive adhesive layer or adhesive layer. Practically, any appropriate protective layer may be provided on the side of the first polarizer 31 and / or the second polarizer 32 where the optical compensation layer is not formed (the side opposite to the liquid crystal cell). Furthermore, if necessary, any appropriate protective layer may be provided on the side of the first polarizer 31 and / or the second polarizer 32 where the optical compensation layer is formed (liquid crystal cell side).

Yes

[0030] A— 2. Liquid crystal cell

The liquid crystal cell 10 used in the present invention includes a pair of substrates 41 and 42 and a liquid crystal layer 43 as a display medium disposed between the substrates. The liquid crystal layer 43 includes liquid crystal molecules that are vertically aligned when no voltage is applied. An example of such a liquid crystal cell is a VA mode liquid crystal cell.

FIG. 2 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in Fig. 2 (a), the liquid crystal molecules are aligned perpendicular to the surfaces of the substrates 41 and 42 when no voltage is applied. 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. In this state, when light is incident from the surface of one substrate 41, linearly polarized light that has passed through the first polarizer 31 and entered the liquid crystal layer 43 is emitted from the vertically aligned liquid crystal molecules. Proceed along the direction of the long axis. Since no birefringence occurs 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 32 having a polarization axis orthogonal to the first polarizer 31. As a result, a display of a heel state can be obtained when no voltage is applied (normally black mode). As shown in Fig. 2 (b), when a voltage is applied between the electrodes, the major axis of the liquid crystal molecules is oriented parallel to the substrate surface. Liquid crystal molecules exhibit birefringence with respect to linearly polarized light incident on the liquid crystal layer 43 in this state, and the polarization state of incident light changes according to the tilt of the liquid crystal molecules. The light passing 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 thus is transmitted through the second polarizer 32 to obtain a bright display. It is done. When no voltage is applied again, the display can be returned to the cocoon state by the orientation regulating force. In addition, gradation display is possible by changing the intensity of transmitted light from the second polarizer 32 by changing the applied voltage to control the tilt of the liquid crystal molecules. [0032] A— 3. First optical compensation layer

The first optical compensation layer has a relationship of Νζ = 1 to 2.5, and has a relationship of Re (380) <Re (550) <Re (780). That is, the first optical compensation layer has negative refractive index wavelength dispersion (reverse dispersion). The first optical compensation layer can suitably compensate for the axial misalignment of the polarizer of the polarizing plate.

[0033] The in-plane retardation Re of the first optical compensation layer is preferably 20 to 180 nm, more preferably 25 to 160 nm, still more preferably 30 to 140 nm.

[0034] The thickness direction retardation Rth of the first optical compensation layer is preferably 20 to 200 nm, more preferably 30 to; 180 nm, and still more preferably 40 to 150 nm.

[0035] The Nz coefficient of the first optical compensation layer is 1 or more, preferably 1.1 or more, and more preferably 1.3 or more. The Nz coefficient of the first optical compensation layer is 2.5 or less, preferably 2.2 or less, more preferably 2.0 or less, and particularly preferably 1.8 or less. . When the Nz coefficient is within the above range, the effect of V can be obtained if the axial misalignment of the polarizer of the polarizing plate can be more preferably compensated.

[0036] The first optical compensation layer, preferably ^{^{70 X 10- 12 (m 2 /}} N) or less, more preferably ^{^{60 X 10 - 12 (m 2}} / N) or less, more preferably 50 X 10- ¹² (m ² / N) or less, still more preferably ^{^{40 X 10- 12 (m 2 /}} N) or less, particularly preferably photoelastic of ^{0 · 1 X 10- 12 ~30 X} 10- 12 (m 2 / N) Has a coefficient. When the photoelastic coefficient is in the above range, the occurrence of phase difference unevenness due to tension at the time of bonding with another optical element can be suppressed, so that an effect of obtaining a liquid crystal panel in which light leakage is suppressed can be obtained. obtain.

[0037] The first optical compensation layer is also preferably Re (780) / Re (550)> 1.1, more preferably 1. K Re (780) / Re (550) <1.6, more preferably Has the relationship 1.15 <Re (780) / Re (550X 1.5. When the first optical compensation layer has the above relationship, the retardation value is constant over a wide visible light region. When used in a liquid crystal display device, it is possible to further reduce the amount of color shift in the oblique direction of the liquid crystal display device, which is less likely to cause a wavelength shift in light leaking light. In this case, light leakage in the red region is reduced, and the display image can be prevented from becoming reddish.

[0038] The first optical compensation layer is also preferably Re (550) / Re (380)> 1.1, more preferably 1. KRe (550) / Re (380) <1. 7, more preferably 1.3 <Re (550) / Re (380X 1.6. The first optical compensation layer has the above relationship. Since the phase difference value is constant over a wide visible light region, the wavelength of the liquid crystal display device in the oblique direction is less likely to cause a wavelength deviation in light leaking when used in a liquid crystal display device. In particular, when used in a liquid crystal display device, light leakage in the blue region can be reduced and the display image can be prevented from being bluish.

[0039] As a material for forming the first optical compensation layer, there is an optical compensation layer having a relationship of Νζ = 1 to 2.5, and a relationship of Re (380) <Re (550) <Re (780). There is no particular limitation as long as it is formed. Examples of such materials include cellulosic materials, polyester materials, polycarbonate materials, polybutyl alcohol materials, polymethyl methacrylate materials, polystyrene materials, acrylonitrile / styrene copolymers, and styrene / anhydrous materials. Examples thereof include maleimide copolymers and maleimidostyrene copolymers. Of these, materials having a non-aromatic cyclic structure and an ester group are preferably substituted with an acetyl group and a propionyl group! /, A cellulose-based material, and a polyester-based material having a non-aromatic cyclic structure. Is more preferable.

[0040] In cellulosic materials substituted with acetyl groups and propionyl groups (hereinafter simply referred to as "cellulosic materials"), the degree of substitution with acetyl groups exists in the cell mouth repeating units. It can be shown by the “degree of substitution of acetyl (DSac)” which indicates how much the three hydroxyl groups on average are substituted by the acetyl group. In the cellulosic material, the degree of substitution with propionyl groups indicates the average amount of substitution by three hydroxyl group propionyl groups present in the repeating unit of cellulose! DSpr) ". The degree of substitution with acetyl (DSac) and the degree of substitution with propylene (DSpr) can be determined by the methods described in JP 2003-315538 A. (0016) to (001 9).

[0041] In the cellulosic material, the degree of acetyl substitution (DSac) and the degree of propionyl substitution (DSpr) preferably satisfy the relational expression of 2.0≤DSac + DSpr≤3.0. The lower limit value of DSac + DSpr is preferably 2.3 or more, more preferably 2.6 or more. The upper limit value of DSac + DSpr is preferably 2.9 or less, more preferably 2.8 or less. Cellulosic material By making DSac + DSpr of the material within the above range, an optical film having desired optical characteristics can be obtained efficiently.

[0042] The cellulosic material preferably has a propionyl substitution degree (DSpr) of 1.0≤D

The relational expression Spr≤3.0 is satisfied. The lower limit of DSpr is preferably 2 or more, more preferably

2. It is 5 or more. The upper limit of DSpr is preferably 2.9 or less, more preferably 2.8 or less. By setting the DSpr of the cellulosic material within the above range, an optical film having desired optical characteristics can be obtained efficiently.

[0043] The cellulosic material may have a substituent other than the acetyl group and the propionyl group. Examples of other substituents include ester groups such as butyrate; ether groups such as alkyl ether groups and araalkylene ether groups;

[0044] 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 within the above range, it is possible to obtain excellent mechanical strength and excellent mechanical strength.

[0045] As a method for substitution to the acetyl group and propionyl group, any appropriate method is 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 degree of substitution “DSac + DSpr” is adjusted by partially hydrolyzing the acyl group.

[0046] The optical film (polymer film) formed from the cellulosic material may include any appropriate polymer material. Examples of such a polymer material include senorelose esterol such as cellulose butyrate; senolen ether ether such as methinoresenorelose and ethinoresenorelose; and the like. The film may contain additives such as a plasticizer, a heat stabilizer, and an ultraviolet stabilizer as necessary.

[0047] Examples of the optical film formed by the above-described cellulose-based material strength include, for example, JP 2003

No. 315538, or US Pat. No. 6,650,581

. Further, as the force and film, a commercially available film such as KA film (manufactured by Kane force Co., Ltd.) can be used.

[0048] Any appropriate material may be adopted as the polyester material. For example, obtained by polymerizing a dicarboxylic acid component having a non-aromatic cyclic structure and a diol component A polyester resin having a non-aromatic cyclic structure and an ester group is preferably used.

[0049] By stretching the optical film formed from the cellulose-based material or the polyester-based material by appropriately selecting stretching conditions (for example, stretching temperature, stretching ratio, stretching direction), stretching method, and the like. A first optical compensation layer having the desired optical characteristics (for example, refractive index ellipsoid, in-plane retardation, thickness direction retardation) can be obtained.

[0050] As the stretching method, for example, any suitable stretching method such as a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, and a longitudinal and transverse sequential biaxial stretching method may be employed. The stretching direction may be the film longitudinal direction (MD direction) or the width direction (TD direction). When the stretching direction is the width direction (TD direction), it can be bonded to other optical elements in a roll shape with a roll-to-roll, and productivity can be greatly improved. It is advantageous for industrial production.

[0051] When the first optical compensation layer is formed by stretching an optical film (polymer film) formed from the cellulose-based material or the polyester-based material, the stretching temperature is preferably 130. ~; 170 ° C, more preferably 140 ~; 150 ° C. The draw ratio is preferably 1.5 to 2.5 times, more preferably 1.9 to 2.3 times. The thickness of the extended finalem formed is preferably 30 to 70〃111, more preferably 40 to 60〃111.

[0052] A— 4. Second optical compensation layer

The second optical compensation layer has a relationship of nx = ny> nz, and Re (380)> Re (550)> Re (

2 2 2

780). That is, the second optical compensation layer is a negative C plate having positive refractive index wavelength dispersion (positive dispersion). The second optical compensation layer can suitably compensate for the birefringence of the liquid crystal cell (positive uniaxial birefringence having positive dispersion: positive C plate component).

In the present specification, “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. It may have a phase difference Re and may have a slow axis. The in-plane retardation Re of the second optical compensation layer is preferably 0 to

2

It is 20 nm, more preferably 0 to 5 nm, still more preferably 0 to 3 nm.

[0054] The thickness direction retardation Rth of the second optical compensation layer is preferably 20 nm or more, more preferably Is 30 to 160 nm, more preferably 70 to 160 nm. Rth is in the above range

2

Liquid crystal cell birefringence (positive uniaxial birefringence with positive dispersion: positive

C plate component) can be suitably compensated.

[0055] The second optical compensation layer is also preferably Re (780) / Re (550) <0.95, more preferably

twenty two

0.8 <Re (780) / Re (550) <0.95, more preferably 0.85 <Re (780) / R

2 2 2

e (550X 0.95 relationship. When the second optical compensation layer has the above relationship,

2

Since the retardation value is constant over a wide area of visible light, when used in a liquid crystal display device, the amount of color shift in the oblique direction of the liquid crystal display device, which is less likely to cause wavelength deviation in light leaking, is further increased. You can power down. In particular, when used in a liquid crystal display device, light leakage in the red region is reduced, and the display image can be prevented from becoming reddish.

[0056] The second optical compensation layer is also preferably Re (550) / Re (380) <0.95, more preferably

twenty two

0.7 <Re (550) / Re (380) <0.9, more preferably 0.75 <Re (550) / Re

2 2 2 2

(It has a relationship of 380X 0.85. When the second optical compensation layer has the above relationship, the phase difference value is constant in a wide region of visible light. It is possible to further reduce the amount of color shift in the oblique direction of a liquid crystal display device, where wavelength deviation is unlikely to occur in leaking light, especially when used in a liquid crystal display device. It becomes small and it can prevent that a display image becomes bluish.

[0057] As the second optical compensation layer, for example, a polymer selected from the group consisting of polyamide, polyimide, polyester, poly (ether ketone), poly (amidoimide) and poly (ester imide) is optically transparent. A layer composed of a biaxially oriented polymer film, a layer in which the cholesteric alignment state of a nematic liquid crystal is fixed, a layer in which the columnar alignment or nematic alignment state of a discotic liquid crystal is fixed, and a negative uniaxial crystal in-plane And a layer oriented in the above.

[0058] Polyamide, polyimide, polyester, poly (ether ketone), poly (amidoimide), or poly (ester imide) that can form the second optical compensation layer are excellent in heat resistance, chemical resistance, and transparency. The polymers described in (0018) to (0072) of JP 2004-46065 Koyuki, et al. Among them, a soluble polyimide (for example, an aromatic dianhydride and a polyaromatic diamine, which has high transparency, high orientation, and high stretchability) JP-A-8-511812) can be preferably used.

[0059] The second optical compensation layer can be formed by applying the polymer to, for example, a resin film or sheet and solidifying. Unlike the liquid crystalline material, the polymer can form a film exhibiting an optical uniaxial property of nx = ny> nz due to its own property that is not related to the orientation of the substrate.

[0060] When polyimide is used as the polymer, the coating method is not particularly limited, and any method can be used. For example, a method of applying a polyimide solution dissolved in a solvent such as heated and melted polyimide or cyclohexanone to a PET film or the like with a thickness of 10 to 30 m can be used. Next, the obtained coating film is, for example, naturally dried (air-dried) or 80 to; heated at 120 ° C. for 8 to 12 minutes to solidify the polyimide on the film, whereby the second optical compensation layer is formed. Can be formed.

[0061] The thickness of the above optically transparent layer of the polymer is preferably 0.;! To 10 111, more preferably 1 to 5 mm. Therefore, the second optical compensation layer formed from the polymer favorably compensates for the birefringence of the liquid crystal cell and contributes to the thinning of the liquid crystal panel.

It is desirable that the layer in which the cholesteric alignment state of the nematic liquid crystal is fixed (hereinafter referred to as “cholesteric alignment solidified layer”) does not have coloration or the like in the visible light region. That is, it is preferable that the selectively reflected light of the cholesteric aligned liquid crystal is not in the visible region. The selective reflection is uniquely determined by the cholesteric chiral pitch and the refractive index of the liquid crystal. The value of the center wavelength of selective reflection may be in the near infrared region, but it is more preferable to be in the ultraviolet region of 350 nm or less in order to avoid the influence of optical rotation.

[0063] The above-described cholesteric alignment solidified layer is, for example, imparted to a cholesteric structure (spiral structure) by applying a twist with a chiral agent in a state where the liquid crystal material exhibits a liquid crystal phase, and in that state, a polymerization treatment or a crosslinking treatment. By applying the above, the alignment (cholesteric structure) of the liquid crystal material can be fixed.

[0064] Specific examples of the cholesteric alignment solidified layer include the cholesteric alignment solidified layer described in JP-A-2003-287623.

[0065] The thickness of the cholesteric alignment solidified layer is preferably 0.;! ~ LO ^ m, more preferably It is;! ~ 5 m. Therefore, the second optical compensation layer, which is a solidified cholesteric alignment layer, can favorably compensate for the birefringence of the liquid crystal cell and contribute to the thinning of the liquid crystal panel.

[0066] The layer in which the columnar alignment or nematic alignment state of the discotic liquid crystal is fixed is, for example, a discotic liquid crystal material having a negative uniaxial property such as a phthalocyanine or a triphenylene compound having a molecular extension in the plane. Further, it can be formed by developing a columnar phase or a nematic phase. Specifically, for example, a layer in which the columnar orientation of the discotic liquid crystal is fixed can be obtained by the method described in JP-A-9-117983.

[0067] As the layer in which the negative uniaxial crystal is oriented in the plane, for example, those described in JP-A-6-82777 can be used.

[0068] Examples of the layer composed of a biaxially oriented polymer film include, for example, a method of biaxially stretching a polymer film having positive refractive index anisotropy in a balanced manner, a method of pressing a thermoplastic resin, and parallel orientation. And a polymer film formed by a method of cutting out from the obtained crystal.

[0069] Examples of a method for biaxially stretching a polymer film having positive refractive index anisotropy in a balanced manner include the ability to simultaneously or sequentially biaxially stretch a film made of a norbornene-based resin under the following conditions. . That is, preferably 120 to; 180 ° C, more preferably 130 to; 170 ° C, stretching temperature, preferably 1.2 to 3 times, more preferably 1.5 to 2.5 times the longitudinal stretching ratio, preferably Is a method of drawing at a transverse draw ratio of 1.2 to 3 times, more preferably 1.5 to 2.5 times.

[0070] A— 5. Third optical compensation layer

The third optical compensation layer has a relationship of Νζ = 1 to 2.5, and Re (380) <Re (550) <Re

3 3 3

(780) relationship. That is, the third optical compensation layer has negative refractive index wavelength dispersion (reverse dispersion). The third optical compensation layer can suitably compensate for the axial misalignment of the polarizer of the polarizing plate.

[0071] For the third optical compensation layer, the description in Section A-3 can be applied. The third optical compensation layer may be the same as or different from the first optical compensation layer. Preferably The third optical compensation layer is formed of the same material as the first optical compensation layer and has the same thickness as the first optical compensation layer.

[0072] A— 6. Fourth optical compensation layer

The fourth optical compensation layer has a relationship of nx = ny> nz, and Re (380)> Re (550)> Re (

4 4 4

780). That is, the fourth optical compensation layer is a negative C plate having positive refractive index wavelength dispersion (positive dispersion). The fourth optical compensation layer can suitably compensate for the birefringence of the liquid crystal cell (positive uniaxial birefringence having positive dispersion: positive C plate component).

[0073] For the fourth optical compensation layer, the description in the section A-4 can be applied. The fourth optical compensation layer may be the same as or different from the second optical compensation layer. Preferably, the fourth optical compensation layer is formed of the same material as the second optical compensation layer and has the same thickness as the second optical compensation layer.

[0074] A— 7. Polarizer

Any appropriate polarizer may be adopted as the polarizer depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes may be added to hydrophilic polymer films such as polyalcohol-based films, partially formalized polybulal alcohol-based films, and ethylene.butyral acetate copolymer-based partially saponified films. Polyethylene-based oriented films such as those that have been adsorbed and uniaxially stretched, polyvural alcohol dehydrated products, and polychlorinated bull dehydrochlorinated products. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polybulualcohol-based 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 !!-80 m.

[0075] A polarizer uniaxially stretched by adsorbing iodine to a polybulualcohol-based film, for example, is dyed by immersing polybulualcohol in an aqueous iodine solution and stretched 3 to 7 times the original length. It is possible to produce with S. If necessary, it may contain boric acid, zinc sulfate, zinc chloride or the like, or may be immersed in an aqueous solution of potassium iodide or the like. Furthermore, if necessary, the polybulal alcohol film may be immersed in water and washed before dyeing.

[0076] By washing the polybulal alcohol-based film with water, the polybulal alcohol-based film Swelling of the surface of the surface and anti-blocking agent as well as swelling of the polybulal alcohol film has the effect of preventing unevenness such as uneven dyeing. The stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be performed after being stretched and then dyed with iodine. Stretch with force S in an aqueous solution of boric acid or potassium iodide or in a water bath.

[0077] A— 8. Other components

A— 8— 1. Protective layer

As the protective layer, any appropriate film that can be used as a protective layer of a polarizer can be adopted. Specific examples of the material that is the main component of such a film include cellulose resins such as triacetyl cellulose mouth (TAC), polyester, polybutyl alcohol, polycarbonate, polyamide, polyimide, and poly Examples thereof include transparent resins such as ether sulfone, polysulfone, polystyrene, polynorbornene, polyolefin, acrylic, and acetate. In addition, thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins, and the like are also included. In addition, for example, a glassy polymer such as a siloxane polymer is also included. Further, JP 2001-343529 Koyuki (WO01 / 37007 can also use the polymer phenol described in this document. Examples of the material of the film include a thermoplastic resin having a substituted or unsubstituted imide group in the side chain, and A resin composition containing a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain can be used.For example, an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer are used. The polymer film can be, for example, an extrusion-molded product of the resin composition, such as TAC, polyimide resin, polybutyl alcohol resin, and glassy polymer. TAC is more preferable.

[0078] The protective layer is preferably transparent and has no color. The protective layer preferably has substantially optical isotropy. In one embodiment, the in-plane retardation of the protective layer is 0 to 10 nm, and the thickness direction retardation is 0 to 10 nm.

[0079] Any appropriate thickness can be adopted as the thickness of the protective layer. Specifically, the thickness of the protective layer is preferably 5 mm or less, more preferably 1 mm or less, and even more preferably. Preferably, it is! -500 μm, and even more preferably 5--150 μm.

[0080] The protective layer provided on the outer side (opposite side of the optical compensation layer) of the polarizer may be subjected to a hard coat treatment, an antireflection treatment, an anti-sticking treatment, an antiglare treatment, or the like as necessary.

[0081] A— 8— 2. Adhesive layer

Arbitrary appropriate adhesives can be employ | adopted as an adhesive which forms an adhesive layer. Specific examples include a solvent-type pressure-sensitive adhesive, a non-aqueous emulsion type pressure-sensitive adhesive, a water-based pressure-sensitive adhesive, and a hot melt pressure-sensitive adhesive. Among these, a solvent-type pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferably used.

[0082] The thickness of the pressure-sensitive adhesive layer can be appropriately set according to the purpose of use, adhesive strength and the like. Specifically, the thickness of the pressure-sensitive adhesive layer is preferably 1 Hm to 100 μm, more preferably 5 μm to 50 μm, and even more preferably 10 μm to 30 μm.

[0083] A— 8— 3. Adhesive layer

A typical example of the adhesive that forms the adhesive layer is a curable adhesive. Typical examples of the curable adhesive include a photocurable adhesive such as an ultraviolet curable adhesive, a moisture curable adhesive, and a thermosetting adhesive.

[0084] The amount of adhesive applied to each layer can be appropriately set according to the purpose. For example, the coating amount is preferably 0.3 to 3 ml, more preferably 0.5 per area (cm ² ) with respect to the main surface of each layer.

5 to 2 ml, more preferably;! To 2 ml.

[0085] After coating, if necessary, the solvent contained in the adhesive is volatilized by natural drying or heat drying. The thickness of the adhesive layer thus obtained is preferably 0.;! To 20 m, more preferably 0.δ-ΐδ, ΐη, and still more preferably ;! to 10 m.

[0086] The pressure-sensitive adhesive or adhesive may be appropriately selected depending on the type of adherend (optical element).

[0087] A— 8— 4. Other optical elements

The liquid crystal panel of the present invention may further include other optical elements. As such another optical element, any appropriate optical element can be adopted depending on the purpose and the type of the liquid crystal display device. Specific examples include liquid crystal films, light scattering films, diffraction films, and Another optical compensation layer (retardation film) and the like can be mentioned.

[0088] B. Manufacturing method of liquid crystal panel

The liquid crystal panel of the present invention, for example, the optical elements can be force ^s is prepared by laminating by via an adhesive layer or an adhesive layer described above. Any appropriate means can be adopted as the lamination means. For example, the first optical compensation layer (third optical compensation layer), the second optical compensation layer (fourth optical compensation layer), and a polarizer are punched out to a predetermined size, and the angle formed by the optical axis of each layer is The directions can be adjusted so as to be within a desired range, and they can be laminated on the liquid crystal cell via an adhesive or an adhesive. In addition, the second optical compensation layer (fourth optical compensation layer) can be directly formed on an adjacent layer, for example, a substrate functioning as a first optical compensation layer, a polarizer or a protective layer. In this case, the pressure-sensitive adhesive layer or adhesive layer for laminating these layers becomes unnecessary, which can contribute to thinning of the liquid crystal panel and simplification of the laminating operation.

[0089] C. Liquid crystal display device

The liquid crystal panel of the present invention can be used in a liquid crystal display device. Liquid crystal display devices are, for example, office equipment such as laptop monitors, notebook computers, and copy machines; mobile devices such as mobile phones, watches, digital cameras, personal digital assistants (PDAs), and portable game machines; video cameras, liquid crystal televisions, and the like. Electrical equipment for home use such as microwave ovens; Back monitors, monitors for car navigation systems, in-car devices such as car audio; monitors for information for commercial stores; first-class display equipment; security equipment such as monitoring monitors; Suitable for nursing care and medical equipment such as monitors and medical monitors.

[0090] Hereinafter, the present invention will be described more specifically by way of examples. The present invention is not limited to these examples.

[0091] [Example 1]

(Preparation of the first optical compensation layer)

A film obtained by stretching a KA film (manufactured by KANEKI Co., Ltd., thickness: 80 m) twice at 150 ° C. at the fixed end was used as a first optical compensation layer. When the phase difference of the obtained film was measured using a phase difference measuring apparatus (manufactured by Oji Scientific Instruments Co., Ltd., KOBRA21ADH), the Re force was 6 nm and the Rth force S50 nm (Nz coefficient = 1.4). The refractive index wavelength dispersion of the film is shown in FIG. Fig. 3 is a graph drawn using Koshii's approximate expression. is there.

[0092] (Preparation of second optical compensation layer)

2,2'-bis (3,4 dicarboxyphenyl) hexafluoropropane (6FDA) and 2,2,1bis (trifluoromethyl) 4,4, -diaminobiphenyl (PFMB or TFMB) was used as a starting material and a polyimide was prepared according to a conventional method. A solution prepared by dissolving the obtained polyimide in cyclohexanone so as to be 15 wt% was applied on a PET film (thickness: 50 m) to a thickness of 20 m. Subsequently, a polyimide film (thickness: about 3πι) was obtained as a second optical compensation layer by performing a drying treatment at 100 ° C. for 10 minutes. The obtained polyimide film was transferred to a glass plate, and the phase difference was measured using a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., KOBRA21ADH). Re was 0.2 nm, Rth

2

The power was OOnm. The refractive index wavelength dispersion of the film is shown in FIG.

2

[0093] (Other optical elements)

The third optical compensation layer and the fourth optical compensation layer were the same as the first optical compensation layer and the second optical compensation layer, respectively. A polarizing plate (manufactured by Nitto Denko Corporation, product number: SIG1423DU) was used as the polarizer.

[0094] (Production of liquid crystal panel)

The second optical compensation layer (fourth optical compensation layer) was transferred from the PET film onto the polarizing plate via an acrylic adhesive (thickness: 20 m). Next, the first optical compensation layer (third optical compensation layer) is passed through an acrylic adhesive (thickness: 20 m) so that its slow axis is perpendicular to the absorption axis of the polarizer of the polarizing plate. And laminated on the second optical compensation layer (fourth optical compensation layer) to obtain two polarizing plates with an optical compensation layer. The two polarizing plates with an optical compensation layer obtained were taken out of a liquid crystal television (manufactured by Sony Corporation, BRAVIA S2000 (32 inches)) on both sides of a VA mode liquid crystal cell. A liquid crystal panel was fabricated by pasting so as to be orthogonal. White and black images are displayed on the liquid crystal display device incorporating the obtained liquid crystal panel, and contrast and color shift (the polar angle in the azimuth angle 45 ° direction is 0 to 80 ° by EZ Contrast (manufactured by ELDIM)). The color shift when tilted and the color shift when the azimuth was changed from 0 to 360 ° at a polar angle of 60 ° were measured. The results are shown in Fig. 4. [0095] [Example 2]

(Preparation of the first optical compensation layer)

A film manufactured in the same manner as in Example 1 (Re: 36 nm, Rth: 50 nm, Nz coefficient: 1.4) was used as the first optical compensation layer.

[0096] (Preparation and lamination of second optical compensation layer)

A cyclohexanone solution (15 wt%) of polyimide prepared in the same manner as in Example 1 was applied on the first optical compensation layer to a thickness of 20 m. Next, by performing a drying treatment at 100 ° C. for 10 minutes, a laminated film in which the second optical compensation layer (polyimide film, thickness: about 3111) was laminated on the first optical compensation layer was obtained. . When the phase difference of the obtained laminated film was measured using a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., KOBRA21ADH), it was found to be: e 35 mm, th force 155 im.

[0097] (Other optical elements)

The third optical compensation layer and the fourth optical compensation layer were the same as the first optical compensation layer and the second optical compensation layer, respectively. The same polarizer as in Example 1 was used as the polarizer.

[0098] (Production of liquid crystal panel)

The laminated film is placed so that the second optical compensation layer (fourth optical compensation layer) faces the polarizing plate, the polarizer's absorption axis of the polarizing plate, and the first optical compensation layer (third optical compensation layer). The optical compensation layer was laminated on a polarizing plate via an acrylic pressure-sensitive adhesive (thickness: 20 m) so that the slow axis of the optical compensation layer was perpendicular to each other to obtain two polarizing plates with an optical compensation layer. Using the obtained two polarizing plates with an optical compensation layer, a liquid crystal panel was produced in the same manner as in Example 1, and the contrast and color shift were measured. The results are shown in FIG.

[0099] [Example 3]

Instead of the protective layer on one side of the polarizing plate (manufactured by Nitto Denko Corporation, SEG1224), the second optical compensation layer (fourth optical compensation layer) and the polarizing plate are facing each other. PVA adhesive (thickness: 0.5) so that the absorption axis of the polarizer of the polarizing plate and the slow axis of the first optical compensation layer (third optical compensation layer) are perpendicular to each other. m) through. As a result, two polarizing plates with an optical compensation layer were obtained. Two polarizations with optical compensation layer obtained A liquid crystal panel was produced using the plate in the same manner as in Example 1, and the contrast and color shift were measured. The result is shown in FIG.

[0100] [Example 4]

(Preparation of the first optical compensation layer)

A film obtained in the same manner as in Example 1 except that the stretching temperature was 140 ° C. was used as the first optical compensation layer. When the retardation of the obtained film was measured, the Re force Onm and Rth were

80 nm (Nz coefficient = 2).

[0101] (Production of second optical compensation layer)

A polyimide film (thickness: about 2 · δ μ ηι) obtained in the same manner as in Example 1 except that the coating thickness of the polyimide cyclohexanone solution (15 wt%) was 16 m was used as the second optical compensation layer. did. When the retardation of the obtained polyimide film was measured, Re was 0.3 nm, Rth was

twenty two

It was 80 nm.

[0102] (Other optical elements)

[0103] (Production of liquid crystal panel)

A liquid crystal panel was produced in the same manner as in Example 1, and the contrast and color shift were measured. The results are shown in FIG.

[Example 5]

(Preparation of the first optical compensation layer)

A film obtained in the same manner as in Example 1 except that the draw ratio was 2.2 times was used as the first optical compensation layer. When the retardation of the obtained film was measured, the Re force Onm and Rth were 60 nm (Nz coefficient = 1 · 5).

[0105] (Production of second optical compensation layer)

A film produced in the same manner as in Example 4 (Re: 0.3 nm, Rth: 80 nm, thickness: about 2.5 μηι

twenty two

) Was used as the second optical compensation layer.

[0106] (Other optical elements) The third optical compensation layer and the fourth optical compensation layer were the same as the first optical compensation layer and the second optical compensation layer, respectively. The same polarizer as in Example 1 was used as the polarizer.

[0107] (Production of liquid crystal panel)

[Example 6]

(Preparation of the first optical compensation layer)

As the dicarboxylic acid component, 1, 4 Cyclohexanedicarboxylic acid to Shikuro (trans isomer: cis isomer = 95: 5) and the di-old Nore component Is and was 100 Monore ^_0/0, as di old Nore components, 9, 9 bis [4 one (2-hydroxyethoxy) phenylene Honoré] fluorene 80 mole ^_0/0, and 1, 4 Shikuro to Cyclohexanedicarboxylic methanol 20 mol% of a synthetic polyester resin was used as a polyester-based material. This polyester resin had an intrinsic viscosity of 0.462 dl / g and a glass transition temperature of 130.1 ° C. A film obtained by stretching the film (thickness: 150 m) formed by this polyester resin strength twice at 135 ° C. twice at a fixed end was used as a first optical compensation layer. When the retardation of the obtained film was measured, the Re force was Sl30 nm: the th force was 40 nm (Nz coefficient = 1.1). The refractive index wavelength dispersion of the obtained film is shown in FIG. 3 (C) together with the refractive index wavelength dispersion of the first optical compensation layer used in Example 1.

[0109] (Production of second optical compensation layer)

Film prepared in the same manner as in Example 1 (Re: 0.2 nm, Rth: lOOnm, thickness: about 3 m)

twenty two

Was used as the second optical compensation layer.

[0110] (Other optical elements)

[0111] (Production of liquid crystal panel)

A liquid crystal panel was produced in the same manner as in Example 1. When the contrast and color shift of this liquid crystal panel were measured in the same manner as in Example 1, the same contrast and color shift as in FIG. One shift is obtained.

[0112] [Example 7]

(Preparation of the first optical compensation layer)

A film produced in the same manner as in Example 6 (Re: 130 nm, Rth: 140 nm, Nz coefficient = 1 · 1) was used as the first optical compensation layer.

[0113] (Production of second optical compensation layer)

twenty two

) Was used as the second optical compensation layer.

[0114] (Other optical elements)

[0115] (Production of liquid crystal panel)

A liquid crystal panel was produced in the same manner as in Example 1. When the contrast and color shift of this liquid crystal panel are measured in the same manner as in Example 1, the same contrast and color shift as in FIG. 7 can be obtained.

[0116] [Comparative Example 1]

Polarizing plate with optical compensation layer for VA mode liquid crystal cell (Nitto Denko Corporation, product name “NIBCOM (NXP)”, optical compensation layer Nz coefficient = 4.8) A liquid crystal panel was prepared by pasting the liquid crystal cell on both sides of the same liquid crystal cell as in Example 1 so as to be orthogonal. Subsequently, the contrast and color shift were measured in the same manner as in Example 1. The results are shown in FIG.

[0117] [Comparative Example 2]

By performing sequential biaxial stretching of norbornene-based resin film (Zeonor, manufactured by Nippon Zeon Co., Ltd.) at 135 ° C, 1.25 times in the horizontal axis direction and 1.03 times in the vertical axis direction, Re becomes 78 nm. There was obtained a retardation film (thickness: 80 m) having an Rth of 170 nm (Nz coefficient = 2 · 2). A polarizing plate (manufactured by Nitto Denko Corporation, SEG1224) is passed through an acrylic pressure-sensitive adhesive (thickness: 20 m) so that the slow axis thereof is perpendicular to the absorption axis of the polarizing plate polarizer. To obtain a polarizing plate with an optical compensation layer. The obtained polarizing plate with an optical compensation layer and a polarizing plate (manufactured by Nitto Denko Corporation, SEG1224) are attached to both sides of the same liquid crystal cell as in Example 1 so that the absorption axes of the polarizers are orthogonal to each other. As a result, a liquid crystal panel was produced. At this time, a polarizing plate with an optical compensation layer was attached to the backlight side. Subsequently, the contrast and color shift were measured in the same manner as in Example 1. The result is shown in FIG.

[0118] [Comparative Example 3]

Retardation film NTAC (Re: 45 nm, Rth: 145 nm, thickness: 80 ^ m, Nz coefficient: 3.2) manufactured by Konica Minolta, Inc., whose slow axis is orthogonal to the absorption axis of the polarizer of the polarizer Thus, two polarizing plates with an optical compensation layer were obtained by laminating on a polarizing plate (SE G1224, manufactured by Nitto Denko Corporation) via an acrylic adhesive (thickness: 20 m). The obtained two polarizing plates with an optical compensation layer were attached to both sides of the same liquid crystal cell as in Example 1 so that the absorption axes of the polarizers were orthogonal to each other to produce a liquid crystal panel. Next, in the same manner as in Example 1, contrast and color shift were measured. The results are shown in FIG.

[Comparative Example 4]

A norbornene-based resin film (Zeon, manufactured by Nippon Zeon Co., Ltd.) is stretched 1.5 times at 160 ° C to obtain a retardation film with a Re of 42 nm and an Rth of 55 nm (thickness: 60 m) was obtained (Nz coefficient = 1 · 3). The refractive index wavelength dispersion of the norbornene-based resin film was so-called flat wavelength dispersion as shown in FIG.

[0120] A polyimide film (Re: 0.3 nm, Rth: 80 nm, thickness: about ^2.5 m) produced in the same manner as the second optical compensation layer of Example 4 was bonded to an acrylic adhesive (thickness: 20 m) and laminated on a polarizing plate (manufactured by Nitto Denko Corporation, SIG1423DU). Next, an acrylic pressure-sensitive adhesive (thickness: 20 m) is formed on the polyimide film so that the retardation film made of the norbornene resin is perpendicular to the absorption axis of the polarizer of the polarizing plate. Then, two polarizing plates with an optical compensation layer were obtained. The obtained two polarizing plates with an optical compensation layer were prepared so that the retardation film made of a norbornene-based resin was opposed to the liquid crystal cell and the absorption axes of the polarizers were orthogonal to each other. A liquid crystal panel was prepared by sticking to both sides of the same liquid crystal cell. Next, the contrast and color shift were measured in the same manner as in Example 1 (because a lot of unevenness was observed on the screen, light was lost! Measured at points). The results are shown in FIG.

[0121] [Comparative Example 5]

Z-TAC film (made by Fuji Film Co., Ltd., film thickness: 80 m), which has substantially optical isotropy, was used instead of PET film, and cyclohexanone solution of polyimide (15 wt%) A polyimide film (thickness: about 2.5 111) was laminated on the Z-TAC film in the same manner as the method for producing the second optical compensation layer in Example 1 except that the coating thickness was set to 16 m. A film was obtained. When the retardation of the obtained laminated film was measured, the Re force was nm and the Rth force was SlOOnm.

[0122] Next, a norbornene-based resin film (Zeonor, manufactured by Nippon Zeon Co., Ltd.) was used instead of PET film, and the coating thickness of the polyimide cyclohexanone solution (15 wt%) was set to 8 am. Except for this, a polyimide film was obtained in the same manner as in the production method of the second optical compensation layer of Example 1. Subsequently, the obtained polyimide film was subjected to free end stretching at 160 ° C. by 2.5 times to obtain a stretched polyimide film (thickness: about 1 m). When the obtained stretched polyimide film was transferred to a glass plate and the phase difference was measured, Re was 40 nm, and th force was 8 nm (Nz coefficient = 1 · 2).

[0123] The above-mentioned stretched polyimide film (Re: 40 nm, Rth: 48 nm, Nz coefficient: 1 · 2) is bonded to the above laminated film (Re: lnm, Rth: lOOnm) via an acrylic adhesive (thickness: 20 m). On the polyimide film layer, it was transferred from a calebornene-based resin film. The laminated film obtained in this manner was so arranged that the Z-TAC film layer was opposite to the polarizing plate (manufactured by Nitto Denko Corporation, SIG1423DU), and the slow axis of the stretched polyimide film and the polarizer absorption of the polarizing plate Two polarizing plates with an optical compensation layer were obtained by laminating with an acrylic pressure-sensitive adhesive (thickness: 20 m) so that the axis was orthogonal. Next, the obtained two polarizing plates with an optical compensation layer were attached to both sides of the same liquid crystal cell as in Example 1 so that the absorption axes of the polarizers were orthogonal to each other, thereby producing a liquid crystal panel. . Subsequently, the contrast and color shift were measured in the same manner as in Example 1. The results are shown in FIG.

[0124] [Comparative Example 6]

A film having positive refractive index wavelength dispersion (positive dispersion) (ARTS1, manufactured by JSR Corporation) is subjected to successive biaxial stretching in the longitudinal and transverse directions at 175 ° C by a factor of 1. Rate distribution: nx = ny> nz, Re: 2 nm, Rth: 220 nm, thickness: 80 m). The obtained phase difference film was laminated on a polarizing plate (manufactured by Nitto Denko Corporation, SEG1224) via an acrylic pressure-sensitive adhesive (thickness: 20 m) to obtain polarizing plate 1 with an optical compensation layer. In addition, a polycarbonate resin film having a negative refractive index wavelength dispersion (reverse dispersion) (manufactured by Teijin Chemicals Ltd., Pure Ace, Re: 145 nm, Rth: 141 nm, thickness: 77 111, Nz coefficient: 1 · 0), The polarizing plate 2 with an optical compensation layer was obtained by laminating with an acrylic pressure-sensitive adhesive (thickness: 20 πι) so that the slow axis and the absorption axis of the polarizer of the polarizing plate were orthogonal to each other. Next, the polarizing plates 1 and 2 with optical compensation layers were attached to both sides of the same liquid crystal cell as in Example 1 so that the absorption axes of the polarizers were orthogonal to each other, thereby producing a liquid crystal panel. Here, the polarizing plate 1 with an optical compensation layer was attached to the backlight side. Subsequently, the contrast and the color shift were measured in the same manner as in Example 1. The results are shown in FIG.

[0125] [Comparative Example 7]

A retardation film 1 (Re: 0.2 nm, Rt h: lOOnm) produced in the same manner as the second optical compensation layer of Example 1 was bonded to a polarizing plate (Nitto) via an acrylic adhesive (thickness: 20 m). The film was transferred from PET film onto Denko Corporation, product number: SIG1423DU). Next, a retardation film 2 (Re: 36 nm, Rth: 50 nm, Nz coefficient: 1 · 4) produced in the same manner as the first optical compensation layer of Example 1, and the slow axis of the polarizer of the polarizing plate A polarizing plate 3 with an optical compensation layer was obtained by being laminated on the retardation film 1 via an talyl-based adhesive (thickness: 20 m) so as to be orthogonal to the absorption axis.

[0126] The above retardation film 2 is coated with a polarizing plate (manufactured by Nitto Denko Corporation) through an acrylic adhesive (thickness: 20 m) so that its slow axis is orthogonal to the absorption axis of the polarizer of the polarizing plate. And product number: SIG1423DU). Next, the retardation film 1 was laminated (transferred) onto the retardation film 2 via an acrylic pressure-sensitive adhesive (thickness: 20, im) to obtain a polarizing plate 4 with an optical compensation layer.

[0127] A liquid crystal panel was produced by pasting the obtained polarizing plates 3 and 4 with an optical compensation layer on both sides of the same liquid crystal cell as in Example 1 so that the absorption axes of the polarizers were orthogonal to each other. . Here, the polarizing plate 4 with an optical compensation layer was attached to the backlight side. Subsequently, the contrast and color shift were measured in the same manner as in Example 1. The results are shown in FIG. [0128] [Comparative Example 8]

Contrast and color shift were measured in the same manner as Comparative Example 7 except that the polarizing plate 3 with an optical compensation layer was attached to the light side and the polarizing plate 4 with an optical compensation layer was attached to the viewing side. The results are shown in FIG.

[0129] Tables 1 and 2 show the outline of the configuration of the liquid crystal panels produced in Examples 1 to 7 and Comparative Examples 1 to 8.

[0130] [Table 1]

Backlight side

¾ ra- ^ ¾ 藜 M¾¾H 薪 ^ H6541818;? U ~~

Compared with the liquid crystal panels of Comparative Examples 1 to 8, the contrast viewing angle characteristics are remarkably improved. Also, the points on the chromaticity diagram indicate that the smaller the movement distance, the smaller the color shift. Therefore, as shown in the xy chromaticity diagrams of Figs. 4 to 14, the liquid crystal panel of Examples;! To 5 is the color when the polar angle is tilted from 0 to 80 ° in the direction of 45 ° azimuth. The shift is also significantly suppressed compared with the liquid crystal panels of Comparative Examples 1 to 6! In the graph showing the relationship between the X and y values and the azimuth, the smaller the (X, y) amplitude is, the smaller the power error shift is. Therefore, as shown in the graph showing the relationship between the X and y values in FIG. 4 to 16 and the azimuth angle, the liquid crystal panels of Examples 1 to 5 change the azimuth angle from 0 to 360 ° at a polar angle of 60 °. It can be seen that the color shift is significantly suppressed compared to the liquid crystal panels of Comparative Examples;! The liquid crystal panel of Comparative Example 6 has a small amplitude in the azimuth angle dependency of the X value and the y value, but the X value curve and the y value curve intersect each other many times. Since the liquid crystal panel having such characteristics varies greatly in color depending on the viewing angle, it gives a viewer a very uncomfortable feeling. As described above, the liquid crystal panel of the example of the present invention is superior in both contrast and color shift compared to the liquid crystal panel of the comparative example.

[0133] [Reference Example 1]

The screens during black display in the liquid crystal display device manufactured in Example 1 and the liquid crystal display device manufactured in Comparative Example 6 were photographed. The photograph is shown in FIG. As shown in FIG. 17, the liquid crystal display device of Example 1 shows no unevenness (light leakage), whereas the liquid crystal display device of Comparative Example 6 shows unevenness on the entire screen and is not at a practical level. I understand. The unevenness observed in Comparative Example 6 is the retardation unevenness due to the tension at the time of laminating each optical element, and is considered to be caused by the large photoelastic coefficient of the used retardation film.

[0134] [Reference Example 2]

KA film used as the first optical compensation layer (third optical compensation layer) in Examples;! To 5, the polyester resin film used in Examples 6 and 7, and the front birefringence used in Comparative Example 6 Table 3 shows the photoelastic coefficients of polycarbonate-based films with negative refractive index and wavelength dispersion. [0135] [Table 3]

[0136] As shown in Table 3, it can be seen that the film used in Comparative Example 6 has a photoelastic coefficient larger than those of Examples;! -7. In other words, the larger the photoelastic coefficient is, the smaller the V and the force the phase difference is manifested. Is easy to occur!

Industrial applicability

[0137] The liquid crystal panel of the present invention contributes to thinning, improves viewing angle characteristics, achieves high contrast, suppresses color shift, and can favorably prevent light leakage in black display.

Claims

The scope of the claims

A liquid crystal cell having a liquid crystal layer containing liquid crystal molecules vertically aligned when no voltage is applied, and disposed on one side of the liquid crystal cell

A first optical compensation layer having a relationship of Nz = l to 2.5, and having a relationship of Re (380) <Re (550) <Re (780);

nx = ny> nz, and Re (380)> Re (550)> Re (780)

2 2 2

Two optical compensation layers;

A first polarizer,

Arranged on the other side of the liquid crystal cell

Nz = l to 2.5, Re (380) <Re (550) <Re (780)

3 3 3

A third optical compensation layer;

nx = ny> nz, and Re (380)> Re (550)> Re (780)

4 4 4

4 optical compensation layers;

A second polarizer,

The first optical compensation layer and the second optical compensation layer, the third optical compensation layer and the fourth optical compensation layer are arranged in a symmetrical positional relationship with respect to the liquid crystal cell. ! /, A liquid crystal panel.

The first optical compensation layer, the second optical compensation layer, and the first polarizer are arranged in this order from the liquid crystal cell on one side of the liquid crystal cell,

2. The third optical compensation layer, the fourth optical compensation layer, and the second polarizer are arranged in this order from the liquid crystal cell on the other side of the liquid crystal cell. LCD panel.

The second optical compensation layer, the first optical compensation layer, and the first polarizer are arranged in this order from the liquid crystal cell on one side of the liquid crystal cell,

2. The fourth optical compensation layer, the third optical compensation layer, and the second polarizer are arranged in this order from the liquid crystal cell on the other side of the liquid crystal cell. LCD panel.

Photoelastic coefficient of the first optical compensation layer and the third optical compensation layer, 70 X 10- ¹² (m ² The liquid crystal panel according to any one of claims 1 to 3, which is not more than / N).

5. The liquid crystal panel according to claim 1, wherein the first optical compensation layer and the third optical compensation layer have a relationship of Re (780) / Re (550)> 1.1.

6. The liquid crystal panel according to claim 1, wherein the first optical compensation layer and the third optical compensation layer are formed from a cellulosic material or a polyester material. The first optical compensation layer and the third optical compensation layer are formed of a material having a non-aromatic cyclic structure and an ester group! / Liquid crystal panel as described.

The liquid crystal panel according to claim 1, wherein the second optical compensation layer and the fourth optical compensation layer have a relationship of Re (780) / Re (550) <0.95.

9. The liquid crystal panel according to claim 1, wherein a thickness direction retardation Rth of the second optical compensation layer and the fourth optical compensation layer is 20 nm or more.

10. The liquid crystal panel according to claim 1, wherein the first optical compensation layer and the third optical compensation layer are polymer films stretched in the width direction.

A liquid crystal display device comprising the liquid crystal panel according to claim 1.