KR101679444B1 - Liquid crystal display apparatus - Google Patents

Abstract

An object of the present invention is to provide a liquid crystal display device which increases a viewing angle, improves a frontal contrast, and prevents a color shift when viewed from an oblique direction. A liquid crystal display 1 according to the present invention includes a first polarizer 2, a first optical compensation layer 3, a liquid crystal cell 4, a second optical compensation layer 5 and a second polarizer 6 And the first and second optical compensation layers 3 and 5 satisfy the following equations (1) to (3), and the liquid crystal molecules in the liquid crystal cell 4 are aligned in the liquid crystal cell 4 in black display, As shown in Fig.
&Quot; (1) "
nx1>nz1> ny1
&Quot; (2) "
nx2? nny2> nz2
&Quot; (3) "
DSP (Ro1) <1 <DSP (Rth2)

Description

[0001] LIQUID CRYSTAL DISPLAY APPARATUS [0002]

The present invention relates to a liquid crystal display device.

Conventionally, a liquid crystal display device is composed of a liquid crystal cell in which a transparent electrode, a liquid crystal layer, a color filter and the like are sandwiched by a glass plate, and two polarizing plates provided on both sides thereof. Each polarizing plate is a polarizer ) Is sandwiched between two optical films (a polarizing plate protective film or an optical compensation film). In this liquid crystal display device, various methods such as VA (Virtical Alignment) mode, IPS (In-Place-Switching) mode and TN (Twisted Nematic) mode have been developed as liquid crystal driving methods. It is fast and has excellent front contrast, so it is widely used in large-screen liquid crystal TV and so on.

In the VA mode liquid crystal display device, since the long axis of the liquid crystal material is aligned perpendicular to the substrate surface when no voltage is applied, substantially complete black display is possible when viewed from a direction perpendicular to the substrate, .

On the other hand, when the liquid crystal material is vertically aligned, there is a problem that coloring occurs in the black display due to light leakage when viewed from the oblique direction, or the contrast is lowered. This problem is mainly caused by two reasons, one of which is that the liquid crystal layer itself used in the liquid crystal cell has a retardation in the thickness direction (also called retardation). Two polarizers sandwiching the liquid crystal cell are arranged at cross Nicolas (the transmission axes are orthogonal to each other). The transmission axes of these polarizers are orthogonal when viewed from the front, but are deviated from the apparent angle of 90 degrees when viewed from the oblique direction do.

In order to solve this problem, the refractive indices nx, ny and nz (where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane and nz is the refractive index in the thickness direction) A technique has been proposed in which two biaxial films are disposed on both sides of a liquid crystal cell to enlarge a viewing angle. In this configuration, although two films of the same kind are used, the cost advantage is obtained, but the effect of enlarging the viewing angle can not be obtained sufficiently.

Therefore, a technique has recently been developed in which a film called negative C plate with nx = ny> nz and a film called Z plate with nx> nz> ny are disposed on the polarizing plate to further increase the viewing angle (for example, , Patent Documents 1 and 2).

However, in the technologies described in the above Patent Documents 1 and 2, the viewing angle is enlarged. However, no consideration is given to the other optical performance, particularly the color shift in the case of viewing from the front contrast and the oblique direction, Further improvement is desired.

Japanese Patent Application Laid-Open No. 2000-39610 Japanese Patent Laid-Open No. 2007-148016

An object of the present invention is to provide a liquid crystal display device which can enlarge a viewing angle, improve a frontal contrast, and prevent a color shift when viewed from an oblique direction.

The inventors of the present invention have conducted extensive research on the above-mentioned problems. Since the conventional Z plate was produced by heat shrinkage of polycarbonate, cycloolefin or the like, it was possible to produce only those having a constant wavelength dispersion (DSP> 1) It has been found that the use of cellulose having a wavelength dispersion (DSP < 1) can produce a Z plate with an inverse wavelength dispersion. In Patent Document 2, it is described that the C plate is preferably reverse wavelength dispersion and the Z plate is constant wavelength dispersion for the wavelength dispersion value DSP. However, the inventors of the present invention have studied extensively, It has been found that the color shift in the case of viewing from the oblique direction can be reduced and the viewing angle and the frontal contrast can be improved when the liquid crystal cell is sandwiched by the C plate of wavelength dispersion. Further, even in the case of using a Z plate of reverse wavelength dispersion, in the case of constituting the Z plate as a single layer, in order to exhibit a viewing angle enlarging effect, a very large retardation with a retardation value Ro of Ro≈275 is given to the Z plate It is necessary to amplify the influence of the deviation of the optical axis in the surface of the Z plate so as to cause a decrease in the front contrast. In the case where the Z plate has the laminated structure of the biaxial film and the liquid crystal layer functioning as the positive C plate , Retardation value Ro = 50 to 100 is applied to the entire Z plate, it is possible to exhibit a viewing angle increasing effect, and it is also possible to reduce phase difference nonuniformity and to maintain the front contrast at a high state Respectively.

In view of the above, according to the first aspect of the present invention, in the liquid crystal display device,

A first optical compensation layer, a liquid crystal cell, a second optical compensation layer, and a second polarizer in this order, at least a first polarizer,

Wherein the first and second optical compensation layers satisfy the following equations (1) to (3)

And the liquid crystal molecules in the liquid crystal cell are oriented in the thickness direction of the liquid crystal cell at the time of black display.

&Quot; (1) &quot;

nx1> nz1> ny1

&Quot; (2) &quot;

nx2? nny2> nz2

&Quot; (3) &quot;

DSP (Ro1) <1 <DSP (Rth2)

(Where nx1 is the refractive index in the slow axis direction in the plane of the first optical compensation layer, ny1 is the refractive index in the fast axis direction in the plane of the first optical compensation layer, and nz1 is the refractive index in the thickness direction of the first optical compensation layer Nx2 is the refractive index in the slow axis direction in the plane of the second optical compensation layer, ny2 is the refractive index in the fast axis direction in the plane of the second optical compensation layer, and nz2 is the refractive index in the thickness direction of the second optical compensation layer Refractive index of the first optical compensation layer, Ro1 represents the in-plane retardation value of the first optical compensation layer represented by the following formula (8-1), Rth2 represents the retardation value of the second optical compensation layer in the thickness direction In-plane retardation value Ro1 of the first optical compensation layer measured at a wavelength of 480 nm as a wavelength dispersion value of the in-plane retardation value Ro1 of the first optical compensation layer, In-plane Rita Day measured at 630 nm (Rth2) is a wavelength dispersion value of the retardation value Rth2 in the thickness direction of the second optical compensation layer, and the retardation value Rth2 of the second optical compensation layer measured at a wavelength of 480 nm is And a retardation value Rth2 measured at a wavelength of 630 nm)

Equation (8-1)

Ro1 = (nx1-ny1) xd1

Equation (9-2)

Rth2 = {(nx2 + ny2) / 2-nz2} xd2

(Where d1 represents the thickness (nm) of the first optical compensation layer, d2 represents the thickness (nm) of the second optical compensation layer, and Ro1 and Rth2 are values measured at a wavelength of 590 nm, respectively)

In the liquid crystal display device of the present invention,

The first optical compensation layer preferably includes a cellulose-based resin layer.

Further, in the liquid crystal display device of the present invention,

The first optical compensation layer satisfies the following expressions (4) and (5)

It is preferable that the second optical compensation layer satisfies the following equations (6) and (7).

&Quot; (4) &quot;

Ro1 = 50 to 100 [nm]

Equation (5)

| Rth1 | = 0 to 20 [nm]

&Quot; (6) &quot;

Ro2 = 0 to 20 [nm]

&Quot; (7) &quot;

Rth2 = 200 to 350 [nm]

(Where Rth1 denotes a retardation value in the thickness direction of the first optical compensation layer represented by the following equation (9-1) and Ro2 denotes a retardation value in a thickness direction of the second optical compensation layer represented by the following equation (8-2) Respectively, and Ro2 and Rth1 are values measured at a wavelength of 590 nm, respectively)

Equation (8-2)

Ro2 = (nx2-ny2) xd2

&Quot; (9-1) &quot;

Rth1 = {(nx1 + ny1) / 2-nz1} xd1

Further, in the liquid crystal display device of the present invention,

Wherein the first optical compensation layer comprises at least a cellulose-based resin layer and a liquid crystal layer,

The above-mentioned cellulose-

Wherein the liquid crystal layer is disposed closer to the first polarizer than the liquid crystal layer,

Plane retardation, and the slow axis is orthogonal to the absorption axis of the first polarizer.

Further, in the liquid crystal display device of the present invention,

Wherein the first optical compensation layer comprises at least a cellulose-based resin layer and a liquid crystal layer,

The above-mentioned cellulose-

Wherein the liquid crystal layer is disposed closer to the liquid crystal cell than the liquid crystal layer,

Plane retardation, and the slow axis is parallel to the absorption axis of the first polarizer.

Further, in the liquid crystal display device of the present invention,

Wherein the second optical compensation layer comprises:

And a cellulose-based resin layer containing a DSP value raising agent.

According to the present invention, the liquid crystal molecules in the liquid crystal cell are oriented in the thickness direction of the liquid crystal cell in black display, and the first and second optical compensation layers are oriented in the order of nx1> nz1> ny1, nx2≥ny2> nz2, DSP (Ro1) <1 <DSP (Rth2), it is possible to increase the viewing angle, improve the front contrast, and prevent the color shift when viewed from the oblique direction (see the embodiment).

1 is a conceptual diagram showing a schematic configuration of a liquid crystal display device according to the present invention.
2 is a conceptual diagram showing a schematic configuration of a modified example of the liquid crystal display device according to the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]

Fig. 1 (a) is a conceptual diagram showing an example of the liquid crystal display device 1 according to the first embodiment.

As shown in this figure, the liquid crystal display device 1 is a VA mode liquid crystal display device and includes a first polarizer 2, a first optical compensation layer 3, a liquid crystal cell The first optical compensation layer 4, the second optical compensation layer 5, and the second polarizer 6 are laminated in this order. More specifically, the first and second polarizers 2 and 6 and the first optical compensation layer 3 are disposed on the surface of the absorption axis 2J of the first polarizer 2 and the first optical compensation layer 3, The axis 3J is orthogonal and the absorption axis 2J of the first polarizer 2 and the absorption axis 6J of the second polarizer 6 are perpendicular to each other and the slow axis 3J of the first optical compensation layer 3 And the absorption axis 6J of the second polarizer 6 are arranged in parallel with each other. In Fig. 1, the backlight is shown as the lower side in the drawing, but may be the upper side. In the present specification, the terms "parallel" and "orthogonal" mean that they are within a range of an exact angle of less than ± 10 °. This range is preferably less than +/- 5 deg., More preferably less than +/- 2 deg., From the strict angle. In this specification, the slow axis means a direction in which the refractive index becomes maximum.

(1) Liquid crystal cell

Among them, the liquid crystal cell 4 is formed by sandwiching the liquid crystal layer 40 between two glass substrates 41.

The liquid crystal layer 40 is composed of rod-shaped liquid crystal molecules, and each liquid crystal molecule is oriented in the thickness direction of the liquid crystal cell 4 at the time of black display. Here, the orientation of the liquid crystal molecules in the thickness direction of the liquid crystal cell 4 in black display means the same as the orientation in the vertical direction of the glass substrate 41, which means that the liquid crystal cell 4 is in the VA mode . The retardation value Rth of the rod-shaped liquid crystal in the liquid crystal cell 4 in the VA mode is negative and its wavelength dispersion is positive.

As the liquid crystal material of the liquid crystal layer 40, a nematic liquid crystal material having a negative dielectric anisotropy, a refractive index anisotropy DELTA n = 0.0815 and a dielectric anisotropy DELTA epsilon = -4.5 or the like can be used. The thickness d of the liquid crystal layer 40 is not particularly limited, but can be set to about 3.5 mu m when the above-mentioned nematic liquid crystal material is used. However, since the brightness at the time of white display changes according to the magnitude of the product? N 占 d of the thickness d and the refractive index anisotropy? N, in order to obtain the maximum brightness, it is preferable to set? N 占 d to be in the range of 0.2 to 0.5 占 퐉 .

In the VA mode liquid crystal display device, addition of a chiral material, which is generally used in a TN mode liquid crystal display device, is rarely used because it deteriorates dynamic response characteristics, but may be added to reduce orientation defects.

In the case of a multi-domain structure, it is also advantageous to adjust the alignment of the liquid crystal molecules in the boundary region between the respective domains.

Here, the multi-domain structure refers to a structure in which one pixel of the liquid crystal display device is divided into a plurality of regions. For example, when white display is performed in the VA mode, the liquid crystal molecules are inclined. Therefore, the magnitude of birefringence of the liquid crystal molecules when observed from the oblique direction differs in the oblique direction and the opposite direction, The domain structure is preferable because the viewing angle characteristics of luminance and color tone are improved. More specifically, it is possible to reduce the luminance and the unevenness of the color tone depending on the viewing angle by constituting each pixel with two or more (preferably four or eight) regions in which the initial alignment states of the liquid crystal molecules are different from each other. Further, the same effect can be obtained when each pixel is constituted by two or more different regions in which the alignment direction of liquid crystal molecules continuously changes in a voltage applied state. In order to form a plurality of regions in which the alignment directions of liquid crystal molecules are different in one pixel, for example, slits are provided in the electrodes, protrusions are formed, the direction of the electric field is changed, or the electric field density is shifted . The number of divisions may be increased in order to obtain an even viewing angle in all directions, but a substantially equal viewing angle can be obtained by dividing the division into four or eight divisions or more. Particularly, it is preferable that the polarizing plate absorption axis can be set at an arbitrary angle at the time of 8 division. At the domain boundary of each domain, the liquid crystal molecules tend to be hard to respond. In the normally black mode such as the VA mode, since the black display is maintained, the luminance deteriorates. Therefore, it is possible to add a chiral agent to the liquid crystal material to reduce the boundary region between the domains. On the other hand, since the white display state is maintained in the normally white mode, the front contrast is lowered. Therefore, a light shielding layer such as a black matrix for covering the area may be provided.

(2) The first and second polarizers

The first and second polarizers 2 and 6 are optical elements that pass only light of a polarization plane in a certain direction and are manufactured by a conventionally known general method. A typical known polarizer is a polyvinyl alcohol polarizing film. More specifically, a polyvinyl alcohol film is dyed with iodine and dyed with a dichroic dye. As such a polarizer, a polyvinyl alcohol aqueous solution is formed, uniaxially stretched and dyed, uniaxially stretched, and preferably subjected to a durability treatment with a boron compound.

Normally, the polarizer is supported on both sides by a TAC film or the like as a protective layer. It is preferable that the back side of the TAC film is subjected to alkali saponification treatment and then bonded to at least one side of the polarizer manufactured by immersion stretching in the iodine solution using a fully saponified polyvinyl alcohol aqueous solution. The above-mentioned TAC film may be used for the other side, or a film having another polarizing plate protecting function may be used. A commercially available cellulose ester film (for example, Konica Minolta Tact KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC4UE, KC8UY, KC4UY, KC12UR, KC4FR or more available from Konica Minolta Opto) is preferably used.

In the configuration of the present invention, the first and second polarizers 2 and 6 are each sandwiched by two TAC films and are bonded to the first and second optical compensation layers 3 and 5 via an adhesive layer But it is preferable to be directly bonded to the optical compensation layers 3 and 5 without interposing the TAC film in terms of thinning, member reduction, and optical compensation.

(3) The first and second optical compensation layers

The first and second optical compensation layers 3 and 5 preferably satisfy the following formulas (1) to (3) and are preferably film-shaped from the viewpoint of handling (hereinafter also referred to as optical compensation films 3 and 5). More preferably, the following expressions (4) to (7) are satisfied.

&Quot; (1) &quot;

nx1> nz1> ny1

&Quot; (2) &quot;

nx2? nny2> nz2

&Quot; (3) &quot;

DSP (Ro1) <1 <DSP (Rth2)

&Quot; (4) &quot;

Ro1 = 50 to 100 [nm]

Equation (5)

| Rth1 | = 0 to 20 [nm]

&Quot; (6) &quot;

Ro2 = 0 to 20 [nm]

&Quot; (7) &quot;

Rth2 = 200 to 350 [nm]

Here, &quot; nx &quot; is the refractive index in the slow axis direction in the plane of the optical compensation layer, &quot; ny &quot; is the refractive index in the fast axis direction in the plane of the optical compensation layer, &Quot; Ro &quot; and &quot; Rth &quot; are retardation values obtained by the following equations (8) and (9). In addition, subscripts &quot; 1 &quot; and &quot; 2 &quot; in the respective expressions indicate values relating to the first optical compensation layer 3 and the second optical compensation layer 5, respectively. These values are values measured at a wavelength of 590 nm. Values of the respective refractive indexes can be obtained under the environment of 23 DEG C and 55% RH using, for example, KOBRA-21ADH (Oji Keisei Kikuchi Co., Ltd.) or Axo scan (manufactured by AXOMETRICS Co., Ltd.).

&Quot; (8) &quot;

Ro = (nx-ny) xd

&Quot; (9) &quot;

Rth = {(nx + ny) / 2-nz} xd)

When the refractive index is nx> nz> ny, Ro> 0 and -Ro / 2 <Rth <Ro / 2 are satisfied. On the other hand, Ro> 0 and -Ro / 2 &Lt; Rth < Ro / 2, it is found that nx> nz> ny is satisfied. In addition, when nx > n > nz, Ro > 0 and Rth > Ro / 2 are satisfied and conversely Ro? 0 and Rth> Ro / .

Is the wavelength dispersion value of the in-plane retardation of the first optical compensation layer 3, specifically, the first optical compensation layer 3 (measured at a wavelength of 480 nm) ) Divided by the retardation value Ro measured at a wavelength of 630 nm. "DSP (Rth2)" is a wavelength dispersion value of retardation in the thickness direction of the second optical compensation layer 5, specifically, a retardation value Rth of the second optical compensation layer 5 measured at a wavelength of 480 nm And a retardation value Rth measured at a wavelength of 630 nm. These wavelength dispersion values DSP become DSP &gt; 1 in the case of positive wavelength dispersion and DSP &lt; 1 in the case of negative wavelength dispersion.

(3.1) First optical compensation layer

As described above, the first optical compensation layer 3 satisfies nx1> nz1> ny1 and DSP (Ro1) <1, and is a so-called Z plate of reverse wavelength dispersion. The first optical compensation layer 3 preferably has an in-plane retardation value Ro1 of 50 to 100 nm and an absolute value of retardation value Rth1 in the thickness direction of 0 nm to 20 nm.

Here, in order to give the first optical compensation layer 3 the performance of nx1> nz1> ny1 and DSP (Ro1) <1, the shrinkable film is bonded to the cellulose resin film having the reverse wavelength dispersibility as described later , It is preferable to shrink while stretching. It is also preferable that the biaxial film obtained by stretching the resin is used as a substrate, and a liquid crystal layer is coated thereon to be dried and immobilized. These will be described in detail with reference to FIG.

The first optical compensation layer 3 is preferably in the form of a film though it is not limited in its form. The thickness d of the film is preferably 40 to 100 mu m, more preferably 40 to 70 mu m.

(3.1.1) Cellulose-based resin used for the first optical compensation layer

The cellulose ester used in the first optical compensation layer (3) is not particularly limited, but preferably cellulose esters having 2 to 22 carbon atoms as the cellulose ester and may be an ester of an aromatic carboxylic acid, And a lower fatty acid ester having 6 or less carbon atoms. Further, a cellulose ester resin obtained by graft-polymerizing? -Caprolactone to a cellulose ester resin as disclosed in JP-A-2008-197561 may be used.

The acyl group bonded to the hydroxyl group may be straight chain, branched or may form a ring. Other substituents may be substituted. When the degree of substitution is the same, the number of carbon atoms is preferably selected from an acyl group having 2 to 6 carbon atoms since the birefringence is deteriorated when the number of carbon atoms is large. The cellulose ester preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.

Specifically, as the cellulose ester, a mixed fatty acid ester of cellulose having a propionate group or a butyrate group bonded thereto in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate or cellulose acetate propionate butyrate may be used.

The butyryl group forming the butyrate may be linear or may be branched. As the cellulose ester preferably used in the present invention, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate and cellulose acetate phthalate are preferably used.

As the cellulose ester other than the cellulose acetate phthalate preferred in the present invention, it is preferable that both of the following equations (101) and (102) are satisfied simultaneously.

&Quot; (101) &quot;

2.0? X + Y? 3.0

Equation (102)

0? Y? 1.5

(Wherein X is the degree of substitution of the acetyl group and Y is the degree of substitution of the propionyl group or the butyryl group, or a mixture thereof)

Further, in order to obtain the optical characteristics according to the purpose, resins having different degrees of substitution may be mixed and used. The mixing ratio is preferably 10:90 to 90:10 (mass ratio).

Of these, cellulose acetate propionate is particularly preferably used. In the cellulose acetate propionate, 1.0? X? 2.5, and 0.1? Y? 1.5 and 2.0? X + Y? 3.0 are preferable. The degree of substitution of the acyl group can be measured according to ASTM-D817-96.

The number average molecular weight of the cellulose ester used in the present invention is preferably in the range of 60,000 to 300,000 because the mechanical strength of the film is high. Further, it is preferably used in the range of from 70000 to 200000.

The weight average molecular weight Mw and the number average molecular weight Mn of the cellulose ester can be measured using gel permeation chromatography (GPC).

The measurement conditions are as follows.

Solvent: methylene chloride

Column: Shodex K806, K805, and K803G (connected by using three connectors manufactured by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: standard polystyrene STK A calibration curve with 13 samples of standard polystyrene (manufactured by Tosoh Corporation) Mw = 1000000 to 500 is used. 13 The samples are used at almost equal intervals.

The cellulose used as the raw material of the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp and kenaf. Further, the cellulose esters obtained therefrom can be mixed and used in an arbitrary ratio.

The cellulose ester such as the cellulose acetate phthalate of the present invention can be produced by a known method. Specifically, it can be synthesized by reference to the method described in Japanese Patent Application Laid-Open (kokai) No. 10-45804.

(3.2) Second optical compensation layer

As described above, the second optical compensation layer 5 satisfies nx2 ≥ny2> nz2, 1 <DSP (Rth2), and is a negative C plate with a so-called constant wavelength dispersion. The second optical compensation layer 5 is preferably Ro2 = 0 to 20 and Rth2 = 200 to 350.

Here, in order to set the retardation value of the second optical compensation layer 5 to the above-mentioned numerical value range, it is preferable to perform the biaxial stretching process. When the second optical compensation layer 5 contains a cellulose ester, in order to minimize the residual strain in the heat treatment and stretching treatment, the glass transition point of the cellulose ester is preferably within a range of about ± 10 ° C Stretched in the conveying direction (longitudinal direction) and in the orthogonal direction (width direction) thereof by about 1.1 to 1.5 times, or the film produced by solution casting is stretched in the conveying direction and in the direction orthogonal thereto in the state in which the residual solvent amount is about 2 to 100 mass% It is preferable to stretch to about 1.1 to 1.7 times.

In this second optical compensation layer 5, it is preferable to control the nonuniformity in the surface. For this purpose, it is preferable to precisely control the balance between the stretching temperature and the stretching ratio, and independently control the stretching portion (such as a clip of the tenter) on both sides of the optical compensation layer 5. This control can be achieved by adjusting the position of the clip and adjusting the stretching temperature and the stretching magnification with respect to the stress of the clip.

The second optical compensation layer 5 is preferably in the form of a film, though not limited thereto. The thickness of the film is 40 to 200 占 퐉, preferably 40 to 120 占 퐉.

(3.2.1) Cellulose-based resin used for the second optical compensation layer

The cellulose ester used in the second optical compensation layer (5) is not particularly limited, and a cellulose ester resin obtained by graft-polymerizing? -Caprolactone to a cellulose ester resin among the cellulose esters usable in the first optical compensation layer (3) Can be used.

(3.2.2) DSP value elevator

In this second optical compensation layer 5, it is preferable to use a DSP value raising agent in order to obtain the effect of the present invention while setting the retardation value in the above numerical range.

DSP enhancer refers to a compound whose DSP (Rth) is increased by 0.001 or more, preferably 0.002 or more by 1% addition.

As the DSP synergist, for example, a triazine-based compound represented by the following formula (II) disclosed in Japanese Patent Application Laid-Open No. 2007-249180 can be used.

&Lt;

(In the formula (II), each of R ¹² independently represents an aromatic ring or a heterocyclic ring having a substituent in at least one of ortho, meta and para positions, X ¹¹ independently represents a single bond or -NR ¹³ - , Wherein each R ¹³ independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group or a heterocyclic group)

As the DSP synergist, a discotic compound may be used.

As the discotic compound, a compound having at least two aromatic rings can be used.

As used herein, the term "aromatic ring" includes an aromatic heterocycle in addition to an aromatic hydrocarbon ring.

It is particularly preferred that the aromatic hydrocarbon ring is a 6-membered ring (i.e., a benzene ring).

An aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocyclic ring is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of the aromatic heterocycle include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furan ring, triazole ring, pyran ring, pyridine ring, Pyridazine ring, pyrimidine ring, pyrazine ring, and 1,3,5-triazine ring.

The aromatic ring is preferably a benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5- And particularly 1,3,5-triazine ring is preferably used. Specifically, for example, the compound disclosed in Japanese Patent Application Laid-Open No. 2001-166144 is preferably used as a discotic compound.

The number of aromatic rings in the above-mentioned discotic compound is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and most preferably 2 to 6.

The bonding relationship of two aromatic rings can be classified into (a) a case where a condensed ring is formed, (b) a case where they are bonded directly to a single bond, and (c) Can not be formed). The bonding relationship may be any one of (a) to (c).

Examples of the condensed rings (condensed rings of two or more aromatic rings) of the aromatic ring (a) include aromatic rings such as a pyridine ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthalene ring, A benzofuran ring, an indoline ring, an indole ring, a benzofuran ring, a benzothiophen ring, an indolizine ring, a benzoxazole ring, a benzothiazole ring, a benzoimidazole ring, a benzotriazole ring, A phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a phenanthrene ring, a quinolin ring, a quinolin ring, Propane ring, phenoxathine ring, phenoxazine ring and thianthrene ring. Naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzoimidazole ring, benzotriazole ring and quinoline ring are preferable.

(b) is preferably a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded to each other by two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between two aromatic rings.

(c) is preferably bonded to the carbon atom of the two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, -CO-, -O-, -NH-, -S- or a combination thereof. An example of a connector made of a combination is shown below. In addition, the left and right relationships of the following connector examples may be reversed. c1: -NH-CO-NH-c5: -NH-CO-O-C6: -O-CO-O-c7 -O-alkylene-O-c8: -CO-alkenylene-c9: -CO-alkenylene-NH-c10: -CO-alkenylene-O- O-CO-alkylene-CO-O-alkylene-CO-alkylene-CO-alkylene- CO-alkenylene-c15: -O-CO-alkenylene-

The aromatic ring and the linking group may have a substituent.

Examples of the substituent include halogen atoms (F, Cl, Br and I), hydroxyl group, carboxyl group, cyano group, amino group, nitro group, sulfo group, carbamoyl group, sulfamoyl group, ureido group, An alkoxycarbonyl group, an alkoxycarbonylamino group, an alkylthio group, an alkylsulfonyl group, an aliphatic amide group, an aliphatic sulfonamide group, an aliphatic substituted amino group, an aliphatic substituted carbamoyl group, an aliphatic acyl group, Aliphatic substituted sulfamoyl groups, aliphatic substituted ureido groups, and non-aromatic heterocyclic groups.

The number of carbon atoms of the alkyl group is preferably 1 to 8. The cyclic alkyl group is preferably a straight chain alkyl group, more preferably a straight chain alkyl group. The alkyl group may further have a substituent (e.g., a hydroxy group, a carboxy group, an alkoxy group, an alkyl substituted amino group). Examples of the alkyl group (including a substituted alkyl group) include a methyl group, ethyl group, n-butyl group, n-hexyl group, 2-hydroxyethyl group, 4-carboxybutyl group, 2-methoxyethyl group, .

The number of carbon atoms of the alkenyl group is preferably 2 to 8. The cyclic alkenyl group is more preferably a chain alkenyl group, and the straight chain alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group and a 1-hexenyl group.

The number of carbon atoms of the alkynyl group is preferably 2 to 8. It is preferably a chain alkynyl group rather than a cyclic alkynyl group, and a straight chain alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include an ethynyl group, a 1-butynyl group and a 1-hexynyl group.

The aliphatic acyl group preferably has 1 to 10 carbon atoms. Examples of the aliphatic acyl group include an acetyl group, a propanoyl group and a butanoyl group.

The aliphatic acyloxy group preferably has 1 to 10 carbon atoms. Examples of the aliphatic acyloxy group include an acetoxy group.

The number of carbon atoms of the alkoxy group is preferably 1 to 8. The alkoxy group may further have a substituent (e.g., an alkoxy group). Examples of the alkoxy group (including the substituted alkoxy group) include a methoxy group, an ethoxy group, a butoxy group and a methoxyethoxy group.

The number of carbon atoms of the alkoxycarbonyl group is preferably 2 to 10. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

The number of carbon atoms of the alkoxycarbonylamino group is preferably 2 to 10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

The alkylthio group preferably has 1 to 12 carbon atoms. Examples of alkylthio groups include methylthio group, ethylthio group and octylthio group.

The number of carbon atoms of the alkylsulfonyl group is preferably 1 to 8. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.

The number of carbon atoms of the aliphatic amide group is preferably 1 to 10. Examples of the aliphatic amide group include an acetamide group.

The aliphatic sulfonamide group preferably has 1 to 8 carbon atoms. Examples of the aliphatic sulfonamide group include a methanesulfonamide group, a butanesulfonamide group and an n-octanesulfonamide group.

The aliphatic substituted amino group preferably has 1 to 10 carbon atoms. Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group and a 2-carboxyethylamino group.

The aliphatic substituted carbamoyl group preferably has 2 to 10 carbon atoms. Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.

The aliphatic substituted sulfamoyl group preferably has 1 to 8 carbon atoms. Examples of the aliphatic substituted sulfamoyl group include a methyl sulfamoyl group and a diethyl sulfamoyl group.

The aliphatic substituted ureido group preferably has 2 to 10 carbon atoms. Examples of aliphatic substituted ureido groups include methylureido groups.

Examples of the non-aromatic heterocyclic group include a piperidino group and a morpholino group.

The molecular weight of the DSP synergist made of a discotic compound is preferably 300 to 800.

In the present invention, rod-shaped compounds having a linear molecular structure other than the above-mentioned discotic compounds can also be preferably used. The linear molecular structure means that the molecular structure of the rod-like compound is linear in the most thermodynamically stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, the molecular orbital calculation is performed using a molecular orbital calculation software (e.g., WinMOPAC2000, manufactured by Fujitsu), and the structure of the molecule in which the heat generation rate of the compound is minimized can be obtained. That the molecular structure is linear means that the angle formed by the main chain in the molecular structure is at least 140 degrees in the most thermodynamically stable structure calculated as described above.

The rod-shaped compound preferably has at least two aromatic rings, and as the rod-like compound having at least two aromatic rings, a compound represented by the following formula (103) is preferable.

&Lt; EMI ID =

Ar ¹ -L ¹ -Ar ²

(In the above formula (103), Ar ¹ and Ar ² are each independently an aromatic group)

In the present specification, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.

An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. Heterocycles of aromatic heterocyclic groups are generally unsaturated. The aromatic heterocyclic ring is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the most double bonds. The hetero atom is preferably a nitrogen atom, an oxygen atom or a sulfur atom, more preferably a nitrogen atom or a sulfur atom.

The aromatic ring of the aromatic group is preferably a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring, Do.

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br and I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group An amino group, a dimethylamino group), a nitro group, a sulfo group, a carbamoyl group, an alkylcarbamoyl group (e.g., N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N- , An alkylsulfamoyl group (e.g., N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), an ureido group, an alkylureido group Butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, t-butyl group, t-butyl group and t-butyl group) An alkenyl group (e.g., vinyl group, allyl group, and hexenyl group), an alkynyl group (e.g., an ethynyl group and a butynyl group), an aralkyl group (For example, formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (for example, acetoxy group, butyryloxy group, hexanoyloxy group, lauryloxy group) (For example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a heptyloxy group and an octyloxy group), an aryloxy group An alkoxycarbonylamino group (e.g., a butoxycarbonylamino group, a hexyloxycarbonylamino group), an alkylthio group (e.g., a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, a butoxycarbonyl group, a pentyloxycarbonyl group or a heptyloxycarbonyl group), an aryloxycarbonyl group (E.g., methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group and octylthio group), arylthio groups (such as phenylthio group), alkylsulfonyl groups A methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, An amide group (e.g., an acetamide group, a butylamido group, a hexylamide group, a laurylamide group) and a nonaromatic heterocyclic group (e.g., morpholyl group , Pyridinyl group).

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom, a cyano group, a carboxyl group, a hydroxyl group, an amino group, an alkyl substituted amino group, an acyl group, an acyloxy group, an amide group, an alkoxycarbonyl group, And an alkyl group are preferable.

The alkyl portion of the alkylamino group, the alkoxycarbonyl group, the alkoxy group and the alkylthio group and the alkyl group may further have a substituent. Examples of the substituent of the alkyl moiety and the alkyl group include a halogen atom, hydroxyl, carboxyl, cyano, amino, alkylamino group, nitro, sulfo, An alkenyl group, an alkynyl group, an acyl group, an acyloxy group, an acylamino group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylamino group, an alkylthio group, an arylthio group, An amide group, and a non-aromatic heterocyclic group. The substituent of the alkyl moiety and the alkyl group is preferably a halogen atom, a hydroxyl group, an amino group, an alkylamino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group and an alkoxy group.

In Formula (103), L ¹ is a divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an alkynylene group, -O-, -CO-, and combinations thereof.

The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As the chain alkylene group, a straight chain alkylene group is preferable to an alkylene group having a branch.

The number of carbon atoms of the alkylene group is preferably 1 to 20, more preferably 1 to 15, still more preferably 1 to 10, particularly preferably 1 to 8, and most preferably 1 to 6 .

 The alkenylene group and the alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably a straight chain structure having a branched structure.

The number of carbon atoms of the alkenylene group and the alkynylene group is preferably 2 to 10, more preferably 2 to 8, still more preferably 2 to 6, particularly preferably 2 to 4, Is 2 (vinylene or ethynylene).

The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, further preferably 6 to 12 carbon atoms.

In the molecular structure of formula (103), it is preferable that the angle formed by Ar ¹ and Ar ² through L ¹ is 140 ° or more.

The rod-shaped compound is more preferably a compound represented by the following formula (104).

&Lt; EMI ID =

Ar ¹ -L ² -XL ³ -Ar ²

(In the above formula (104), Ar ¹ and Ar ² are each independently an aromatic group, and the definitions and examples of the aromatic group are the same as Ar ¹ and Ar ² in the formula (103)

In Formula 104, L ² and L ³ are each independently a divalent linking group selected from the group consisting of an alkylene group, -O-, -CO-, and combinations thereof.

The alkylene group preferably has a chain structure rather than a cyclic structure, and more preferably has a straight chain structure rather than a chain structure having a branch.

The number of carbon atoms of the alkylene group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, still more preferably 1 to 4, 1 or 2 (methylene or ethylene) Is most preferable.

It is particularly preferable that L ² and L ³ are -O-CO- or -CO-O-.

In Formula 104, X is 1,4-cyclohexylene, vinylene or ethynylene.

Specific examples of the compound represented by the formula (103) or (104) include the compounds described in [1] to [11] of Japanese Patent Laid-Open Publication No. 2004-109657.

Other preferred compounds are shown below.

In the ultraviolet absorption spectrum of the solution, two or more rod-shaped compounds having a maximum absorption wavelength (? Max) shorter than 250 nm may be used in combination.

The rod-shaped compound can be synthesized by the method described in the literature. As a document, [Mol. Cryst. Liq. Cryst., 53, 229 (1979), 89, 93 (1982), 145, 111 (1987), 170, 43 (1989) J. Am. Chem. Soc., 113, 1349 (1991), 118, 5346 (1996), 92, 1582 (1970), J. Org. Chem., Vol. 40, p. 420 (1975), Tetrahedron, Vol. 48, No. 16, pp. 3437 (1992)].

(3.3) Additive

The first and second optical compensation layers (3, 5) described above may contain an additive agent if necessary in order to obtain the effect of the present invention. The additive is not particularly limited, but preferably an aromatic terminal polyester compound, a sugar ester compound, a (meth) acrylic compound, a polycarboxylic acid ester compound, a glycolate compound, a phthalate ester compound, A polyhydric alcohol ester-based compound, a polyester-based plasticizer, and the like.

(3.3.1) aromatic terminal polyester compound

In the present invention, an aromatic terminal polyester compound represented by the following formula (I) may be used.

(I)

B- (G-A) n-G-B

Wherein G is an alkylene glycol residue having 2 to 12 carbon atoms or an aryl glycol residue having 6 to 12 carbon atoms or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A is an alkylene glycol residue having 4 to 12 carbon atoms Or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more)

In formula (I), an alkylene glycol residue or an oxyalkylene glycol residue or an aryl glycol residue represented by G, an alkylene dicarboxylic acid residue represented by A or an aryl dicarboxylic acid residue represented by A And can be obtained by the same reaction as a usual polyester compound.

Examples of the arylcarboxylic acid component of the aromatic terminal polyester compound used in the present invention include benzoic acid, para-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, Benzoic acid, aminobenzoic acid, and acetoxybenzoic acid, and these may be used individually or as a mixture of two or more kinds.

Examples of the alkylene glycol component having 2 to 12 carbon atoms in the aromatic terminal polyester compound usable in the present invention include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3 Butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2- ), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) Methyl-1,5-pentanediol-1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, , 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like, and these glycols are used singly or as a mixture of two or more kinds.

Particularly preferred are alkylene glycols having 2 to 12 carbon atoms since they are excellent in compatibility with cellulose esters.

Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms in the aromatic terminal polyester compound include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. These glycol Can be used singly or as a mixture of two or more kinds.

Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms in the aromatic terminal polyester compound include unsaturated carboxylic acids such as succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid Etc., which are used as one kind or a mixture of two or more kinds respectively.

Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, and 1,4-naphthalene dicarboxylic acid.

The aromatic terminal polyester compound used in the present invention preferably has an n of 1 or more and 100 or less, and preferably has a number average molecular weight of 300 to 1,500, more preferably 400 to 1,000.

The acid value thereof is 0.5 mgKOH / g or less, the hydroxyl value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less.

The aromatic terminal polyester compound represented by the formula (I) of the present invention is preferably contained in an amount of 0.5 to 30 mass% with respect to the cellulose ester.

Hereinafter, specific compounds of the aromatic-terminal polyester-based compounds usable in the present invention are shown, but the present invention is not limited thereto.

The additives described below are suitably used for the first and second optical compensation layers according to the present invention.

(3.3.2) ester compound

In the first and second optical compensation layers (3, 5) of the present invention, at least one of the pyranose structure or the furanose structure is contained in an amount of 1 to 12, and all or a part of the OH groups of the structure And an esterified ester compound (sugar ester compound).

The ratio of esterification is preferably 70% or more of OH groups present in the pyranose structure or furanose structure.

In the present invention, the ester compound is collectively referred to as a sugar ester compound.

Examples of the ester compound of the present invention include, for example, the following compounds, but the present invention is not limited thereto.

The present invention also relates to a pharmaceutical composition for preventing or treating diabetes mellitus comprising glucose, galactose, mannose, fructose, xylose, or arabinose, lactose, sucrose, Maltose, celotriose, maltotriose, raffinose or kestose.

In addition to these, gentiobiose, gentiootriose, gentiootetraose, xylotriose, galactosyl sucrose and the like can be mentioned.

Of these compounds, compounds having both a pyranose structure and a furanose structure are particularly preferred.

Examples thereof are sucrose, cetostose, nisthos, 1F-fructosylnitose, stachyose and the like, more preferably sucrose.

The monocarboxylic acid used for esterifying all or a part of the OH groups in the pyranose structure or the furanose structure of the present invention is not particularly limited and includes aliphatic monocarboxylic acids and alicyclic monocarboxylic acids , An aromatic monocarboxylic acid, and the like. The carboxylic acid to be used may be one kind or a mixture of two or more kinds.

Preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethylhexanecarboxylic acid, But are not limited to, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, Unsaturated fatty acids such as montanic acid, melissic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linolic acid, linolenic acid, arachidonic acid and octetic acid.

Examples of preferred alicyclic monocarboxylic acids include acetic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid and derivatives thereof.

Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids, cinnamic acids, benzilic acids, biphenylcarboxylic acids, naphthalenecarboxylic acids, naphthalenecarboxylic acids, and the like, which are obtained by introducing alkyl groups or alkoxy groups into benzene rings of benzoic acids such as benzoic acid and toluic acid. And aromatic carboxylic acids having two or more benzene rings such as tricyclic carboxylic acid and derivatives thereof, and more specifically, xylylic acid, hemelitic acid, mesitylene acid, Acetic acid, hydrosinic acid, salicylic acid, o-anisic acid, m-anisic acid, p-nonanhydric acid, But are not limited to, acetic acid, succinic acid, acetic acid, creosotic acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocatecholic acid,? -Resoricylic acid, vanillic acid, isobanilic acid, veratric acid, , Ascorbic acid, mandelic acid, homoanisan, homobanilic acid, homo O-homobaric acid, phthalic acid, and p-cumaric acid, but benzoic acid is particularly preferable.

The ester compound of the oligosaccharide can be applied as a compound having 1 to 12 of at least one of the pyranose structure or the furanose structure in the present invention.

Examples of the oligosaccharide applicable to the present invention include maltooligosaccharide, isomaltooligosaccharide, fructo-oligosaccharide, galacto-oligosaccharide, and xylooligosaccharide. have.

The ester compound is a compound obtained by condensing at least one of a pyranose structure or a furanose structure represented by the following formula (A) in an amount of 1 to 12. M and n each represent an integer of 0 to 12, and m + n represents an integer of 1 to 12, provided that R ₁₁ to R ₁₅ and R ₂₁ to R _{25 each} represent an acyl group or a hydrogen atom having 2 to 22 carbon atoms;

&Lt; Formula (A)

R ₁₁ to R ₁₅ and R ₂₁ to R ₂₅ are preferably a benzoyl group or a hydrogen atom. The benzoyl group may further have a substituent R ₂₆ (p is 0 to 5), and examples thereof include an alkyl group, an alkenyl group, an alkoxyl group and a phenyl group. The alkyl group, alkenyl group and phenyl group may further have a substituent. Oligosaccharides can also be produced by the same method as the ester compound of the present invention.

Specific examples of the ester compound in the present invention are shown below, but the present invention is not limited thereto.

In order to suppress the fluctuation of the retardation value and stabilize the display quality, the cellulose ester film of the present invention (first and second optical compensatory layers (3, 5)) preferably contains the sugar ester compound of the present invention in an amount of 0.5 to 30 By mass, more preferably from 5 to 30% by mass.

(3.3.3) (meth) acrylic compound

The (meth) acrylic compound used in the present invention preferably has negative birefringence with respect to the stretching direction as contained in the optical compensation film, and is not particularly limited in its structure, but may be obtained by polymerizing an ethylenically unsaturated monomer And a polymer having a weight average molecular weight of 500 or more and 30,000 or less is preferable.

(Birefringence test method of (meth) acrylic compound)

(Meth) acrylic polymer (compound) was dissolved in a solvent to form a cast film, followed by heating and drying, and the birefringence of the film having a transmittance of 80% or more was evaluated.

The refractive index was measured using an Abbe's refractive index-4T (manufactured by Atago Co., Ltd.) using a multi-wavelength light source. The refractive index ny in the stretching direction and the refractive index in the in-plane direction perpendicular to each other are defined as nx. (Meth) acrylic polymer is judged to be negative birefringence with respect to the stretching direction, with respect to a film having (ny-nx) &lt; 0 with respect to each refractive index of 550 nm.

The (meth) acrylic polymer having a weight average molecular weight of 500 to 30000 as used in the present invention may be a (meth) acrylic polymer having an aromatic ring in its side chain or a (meth) acrylic polymer having a cyclohexyl group in its side chain.

When the polymer has a weight average molecular weight of 500 or more and 30,000 or less and the composition of the polymer is controlled, for example, when the optical compensation film is a particularly preferable cellulose ester film in the present invention, the compatibility of the cellulose ester with the polymer is preferably can do.

(Meth) acryl-based polymer having an aromatic ring in its side chain or a (meth) acryl-based polymer having a cyclohexyl group in its side chain preferably has a weight average molecular weight of 500 or more and 10000 or less. Excellent transparency, extremely low moisture permeability, and excellent performance as a protective film for a polarizing plate.

Since the polymer has a weight average molecular weight of 500 or more and 30,000 or less, it is considered that oligomers are present between low molecular weight polymers. In order to synthesize such a polymer, it is difficult to control the molecular weight as an ordinary polymer. Therefore, it is preferable not to increase the molecular weight so much, and it is preferable to use a method capable of aligning the molecular weight as much as possible.

In particular, as the (meth) acrylic polymer used in the optical compensation film of the present invention, an ethylenically unsaturated monomer Xa having no aromatic ring and no hydroxyl group in the molecule, an ethylenically unsaturated monomer Xb having a hydroxyl group and no aromatic ring in the molecule, Polymer X having a weight average molecular weight of 2000 to 30000, obtained by copolymerizing a copolymerizable ethylenically unsaturated monomer excluding Xa and Xb, or an ethylenically unsaturated monomer Ya having no aromatic ring, and an ethylenically unsaturated monomer copolymerizable with Ya are polymerized It is preferable that the polymer Y is a polymer Y having a weight average molecular weight of 500 or more and 3,000 or less.

[Polymer X, Polymer Y]

Examples of the method for adjusting Ro and Rth of the optical compensation film in the present invention include an ethylenically unsaturated monomer Xa having no aromatic ring and no hydroxyl group in the molecule and an ethylenically unsaturated monomer Xb having no aromatic ring in the molecule but having a hydroxyl group, A high molecular weight polymer X having a weight average molecular weight of 2000 to 30000 obtained by copolymerizing a copolymerizable ethylenically unsaturated monomer excluding Xa and Xb, more preferably an ethylenically unsaturated monomer Ya having no aromatic ring and an ethylene- Molecular-weight polymer Y having a weight-average molecular weight of 500 or more and 3,000 or less, obtained by polymerizing an unsaturated monomer.

The polymer X used in the present invention is a polymer X having an ethylenically unsaturated monomer Xa having no aromatic ring and no hydroxyl group in the molecule, an ethylenically unsaturated monomer Xb having no hydroxyl group in the molecule but having a hydroxyl group, Average molecular weight of 2000 to 30000 obtained by copolymerizing an unsaturated monomer.

Preferably, Xa is an acrylic or methacrylic monomer having no aromatic ring and no hydroxyl group in the molecule, and Xb is an acrylic or methacrylic monomer having no aromatic ring in the molecule and having a hydroxyl group.

Polymer X used in the present invention is represented by the following formula (X).

(X)

- [Xa] m- [Xb] n- [Xc] p-

(Xa represents an ethylenically unsaturated monomer having no aromatic ring and no hydroxyl group in the molecule, Xb represents an ethylenically unsaturated monomer having no aromatic ring in the molecule but a hydroxyl group, Xc represents an ethylenically unsaturated monomer other than Xa and Xb M, n and p each represent a molar composition ratio, provided that m ≠ 0, n ≠ 0, and m + n + p = 100)

The polymer X is preferably a polymer represented by the following formula (X-1).

&Lt; General Formula (X-1)

- [CH ₂ -C (-R 1) (-CO ₂ R ₂ )] m- [CH ₂ -C (-R 3) (-CO ₂ R 4 -OH)

(Wherein R 1 and R 3 are each a hydrogen atom or a methyl group, R 2 is an alkyl group or a cycloalkyl group having 1 to 12 carbon atoms, R 4 is -CH ₂ -, -C ₂ H ₄ - or - C ₃ H ₆ - represents the, Xc is _{[CH 2 -C (-R1) (} - CO 2 R2)] or _{[CH 2 -C (-R3) (} - CO 2 R4-OH) -] polymerizable monomer on M, n and p represent molar composition ratios, where m? 0, n? 0, and m + n + p = 100)

Examples of the monomer as the monomer unit constituting the polymer X used in the present invention include, but are not limited to, the following.

The hydroxyl group in X means not only a hydroxyl group but also a group having an ethylene oxide chain.

Examples of the ethylenically unsaturated monomer Xa having no aromatic ring and no hydroxyl group in the molecule include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, (N-, i-), acrylate (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate -), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (epsilon -caprolactone) and the like or those obtained by changing the above acrylic acid ester to methacrylic acid ester. Of these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and propyl methacrylate (i-, n-) are preferable.

The ethylenically unsaturated monomer Xb having no aromatic ring in the molecule and having a hydroxyl group is preferably acrylic acid or methacrylic acid ester as a monomer unit having a hydroxyl group, and examples thereof include acrylic acid (2-hydroxyethyl), acrylic acid (2- Hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl) or those obtained by substituting acrylic acid with methacrylic acid, (2-hydroxyethyl) and methacrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), and acrylic acid (3-hydroxypropyl).

Xc is not particularly limited as long as it is a monomer other than Xa and Xb and is copolymerizable with an ethylenically unsaturated monomer, but preferably has no aromatic ring.

The molar composition ratio m: n of Xa and Xb is preferably in the range of 99: 1 to 65:35, and more preferably in the range of 95: 5 to 75:25. And p in Xc is 0 to 10. Xc may be a plurality of monomer units.

When the molar composition ratio of Xa is large, compatibility with the cellulose ester is improved, but the retardation value Rth in the film thickness direction is increased. When the molar composition ratio of Xb is large, the compatibility is deteriorated, but the effect of reducing Rth is high.

If the molar composition ratio of Xb exceeds the above range, haze tends to occur at the time of film formation. Therefore, it is preferable to determine the molar composition ratio of Xa and Xb by optimizing these.

The molecular weight of the high molecular weight polymer X is more preferably from 5,000 to 30,000, and still more preferably from 8,000 to 25,000.

By setting the weight average molecular weight to 5,000 or more, it is preferable that the optical compensation film has a small dimensional change under high temperature and high humidity, and the curtain of the polarizing plate protective film is small.

When the weight average molecular weight is 30,000 or less, compatibility with the cellulose ester is further improved, bleeding out under high temperature and high humidity, and generation of haze immediately after the film formation are suppressed.

The weight average molecular weight of the polymer X used in the present invention can be adjusted by a known molecular weight control method. Examples of the molecular weight control method include a method of adding a chain transfer agent such as carbon tetrachloride, lauryl mercaptan, and octyl thioglycolate.

The polymerization temperature is usually from room temperature to 130 ° C, preferably from 50 ° C to 100 ° C, but it is possible to adjust the temperature or the polymerization reaction time.

As the method for measuring the average molecular weight, the above-mentioned method can be used in (3.1.1).

The low molecular weight polymer Y used in the present invention is a polymer having a weight average molecular weight of 500 to 3000 obtained by polymerizing an ethylenically unsaturated monomer Ya having no aromatic ring. If the weight average molecular weight is 500 or more, the residual monomers of the polymer are reduced.

Further, it is preferable to set it to 3000 or less in order to maintain the retardation value Rth degradation performance. Ya is preferably an acrylic or methacrylic monomer having no aromatic ring.

Polymer Y used in the present invention is represented by the following formula (Y).

&Lt; Formula Y &

- [Ya] k- [Yb] q-

In the formula (Y), Ya represents an ethylenically unsaturated monomer having no aromatic ring, and Yb represents an ethylenically unsaturated monomer copolymerizable with Ya. k and q each represent a molar composition ratio. However, k ≠ 0, q ≠ 0, and k + q = 100.

In the polymer Y used in the present invention, it is more preferably a polymer represented by the following formula (Y-1).

&Lt; Formula Y-1 &

- [CH ₂ -C (-R 5) (-CO ₂ R 6)] k- [Yb] q-

In the formula (Y-1), R5 represents a hydrogen atom or a methyl group. R6 represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group. Yb represents a monomer unit copolymerizable with [CH ₂ -C (-R 5) (-CO ₂ R 6)]. k and q each represent a molar composition ratio. Where k ≠ 0, q ≠ 0, and k + q = 100.

Yb is not particularly limited as long as it is an ethylenically unsaturated monomer copolymerizable with [CH ₂ -C (-R 5) (-CO ₂ R 6)] Ya. Yb may be plural. k + q = 100, and q is preferably 1 to 30. [

The ethylenically unsaturated monomer Ya constituting the polymer Y obtained by polymerizing an ethylenically unsaturated monomer having no aromatic ring is preferably an acrylic acid ester such as methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate acrylic acid (epsilon -caprolactone), acrylic acid (2-ethylhexyl acrylate), acrylic acid (2-ethylhexyl acrylate) Acrylic acid (2-hydroxybutyl), acrylic acid (2-hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid The ester is changed to methacrylic acid ester; Examples of the unsaturated acid include acrylic acid, methacrylic acid, maleic anhydride, crotonic acid, itaconic acid, and the like.

Yb is not particularly limited as long as it is an ethylenically unsaturated monomer copolymerizable with Ya, and examples thereof include vinyl acetate such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl pivalate, vinyl caprate, Vinyl propionate, vinyl propionate, vinyl propionate, vinyl propionate, vinyl butyrate, vinyl butyrate, vinyl stearate, vinyl stearate, vinyl stearate, Yb may be plural.

In order to synthesize the polymers X and Y, it is difficult to control the molecular weight by ordinary polymerization. Therefore, it is preferable not to increase the molecular weight so much, and it is preferable to use a method capable of aligning the molecular weight as much as possible.

Examples of such polymerization methods include a method of using a peroxide polymerization initiator such as cumene peroxide or t-butyl hydroperoxide, a method of using a polymerization initiator in a larger amount than that of usual polymerization, a method of using a mercapto compound or a chain transfer agent such as carbon tetrachloride A method of using a polymerization terminator such as benzoquinone or dinitrobenzene in addition to the polymerization initiator, a method of using one thiol group and a hydroxyl group of a secondary hydroxyl group in Japanese Patent Laid-Open Nos. 2000-128911 or 2000-344823 Or a method in which bulk polymerization is carried out by using a polymerization catalyst obtained by using the above compound in combination with an organometallic compound, and the like, all of which are preferably used in the present invention.

Particularly, the polymer Y is preferably a polymerization method using a compound having a thiol group and a secondary hydroxyl group in the molecule as a chain transfer agent. In this case, the terminal of the polymer Y has a hydroxyl group and a thioether due to a polymerization catalyst and a chain transfer agent. This terminal residue can adjust the compatibility of Y and the cellulose ester.

The hydroxyl value of the polymers X and Y is preferably 30 to 150 mgKOH / g.

(Method for measuring hydroxyl value)

The measurement of the hydroxyl value is in accordance with JIS K 0070 (1992). This hydroxyl value is defined as the number of mg of potassium hydroxide needed to neutralize the acetic acid bound to the hydroxyl group when 1 g of the sample is acetylated.

Specifically, sample Xg (about 1 g) is accurately weighed into a flask, and 20 ml of an acetylating reagent (prepared by adding pyridine to 20 ml of acetic anhydride to make 400 ml) is accurately added. An air cooling tube is attached to the inlet of the flask and heated in a glycerin bath at 95 to 100 ° C. After 1 hour and 30 minutes, it is cooled, 1 ml of purified water is added from an air cooling tube, and acetic anhydride is decomposed with acetic acid.

Subsequently, titration is carried out with a 0.5 mol / l potassium hydroxide ethanol solution using a potentiometric titration apparatus, and the inflection point of the titration curve obtained is used as an end point.

Further, as a blank test, the inflection point of the titration curve is determined by titration without adding a sample. The hydroxyl value is calculated by the following equation.

Hydroxyl value = {(B-C) x f x 28.05 / X} + D

(B) is the amount (ml) of the 0.5 mol / l potassium hydroxide ethanol solution used in the blank test, C is the amount (ml) of the 0.5 mol / l potassium hydroxide ethanol solution used in the titration, f is 0.5 mol / D represents the acid value, and 28.05 represents 1/2 of 56.11 for 1 mol of potassium hydroxide)

All of the polymer X and the polymer Y described above are excellent in compatibility with a cellulose ester, have excellent productivity without evaporation or volatilization, have good retention as a protective film for a polarizing plate, have a low moisture permeability and excellent dimensional stability.

The content of the polymer X and the polymer Y in the optical compensation film is such that the content of the polymer X is Xg (mass% = (mass of polymer X / mass of cellulose ester) x 100) and the content of polymer Y is Yg (mass%) , It is preferable that the range satisfies the following expressions (i) and (ii).

&Lt; EMI ID =

5? Xg + Yg? 35 (mass%)

&Lt; EMI ID =

0.05? Yg / (Xg + Yg)? 0.4

The preferable range of (Xg + Yg) in the formula (i) is 10 to 35 mass%. The polymer X and the polymer Y have a function sufficient to adjust the retardation value Rth when the total amount is 5% by mass or more based on the total mass of the cellulose ester. When the total amount is 35% by mass or less, adhesion with the polarizer PVA is good.

The polymer X and the polymer Y can be added directly to the dope solution as a material for forming a dope liquid to be described later, dissolved or dissolved in an organic solvent which dissolves the cellulose ester, and then added to the dope solution.

(3.4) Ultraviolet absorber

In addition, the first and second optical compensatory layers 3 and 5 may contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet rays of 400 nm or less, and particularly preferably has a transmittance at a wavelength of 370 nm of 10% or less, more preferably 5% or less, further preferably 2% Or less.

The ultraviolet absorber to be used in the present invention is not particularly limited, and examples thereof include oxybenzophenone compounds, benzotriazole compounds, salicylic ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, Based compounds, inorganic powders, and the like.

Benzotriazole, (2-2H-benzotriazol-2-yl) -6- (3,5-di-sec- (Straight chain and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone and the like, and also Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327 and Tinuvin 328, all of which are commercially available from Shiba Japan Co., Ltd. and can be preferably used.

The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber.

For example, as the benzotriazole-based ultraviolet absorber, a compound represented by the following formula (d) can be used.

<Formula d>

(Wherein, R _1, R _2, R _3, R ₄ and R ₅ are good and may be the same or different may represent a hydrogen atom, a halogen atom, a nitro group, a hydroxyl group, an alkyl group, an alkenyl group, an aryl group, an alkoxyl group, An aryloxy group, an acyloxy group, an aryloxy group, an alkylthio group, an arylthio group, a mono or dialkylamino group, an acylamino group or a 5- to 6-membered heterocyclic group, and R ₄ and R ₅ are cyclized to form a 5- to 6- Also,

In addition, these groups described above may have arbitrary substituents.

Specific examples of the benzotriazole ultraviolet absorber used in the present invention are set forth below, but the present invention is not limited thereto.

UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole

UV-2: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole

UV-3: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole

UV-4: 2- (2'-hydroxy-3 ', 5'-di-tert- butylphenyl) -5-chlorobenzotriazole

UV-5: 2- (2'-hydroxy-3'- (3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-

UV-6: 2,2-methylene bis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-

UV-7: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole

UV-8: 2- (2H-benzotriazol-2-yl) -6- (straight and branched dodecyl) -4-methylphenol (Tinuvin 171)

UV-9: octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol- (tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate

As the benzophenone ultraviolet absorber, a compound represented by the following formula (e) is preferably used.

<Formula e>

(Wherein Y represents a hydrogen atom, a halogen atom or an alkyl group, an alkenyl group, an alkoxyl group and a phenyl group, and the alkyl group, alkenyl group and phenyl group may have a substituent, and A represents a hydrogen atom, an alkyl group, an alkenyl group, An alkyl group, an alkylsulfonyl group or an -CO (NH) n-1-D group, D represents an alkyl group,

Examples of the alkyl group include straight chain or branched aliphatic groups having up to 24 carbon atoms. Examples of the alkoxyl groups include alkoxyl groups having up to 18 carbon atoms. Examples of the alkenyl groups include alkenyl groups having up to 16 carbon atoms. A 2-butenyl group, and the like. Examples of the substituent for the alkyl group, the alkenyl group and the phenyl group include a halogen atom such as a chlorine atom, a bromine atom and a fluorine atom, a hydroxyl group, a phenyl group (the phenyl group may be substituted with an alkyl group or a halogen atom) .

Specific examples of the benzophenone ultraviolet absorber represented by the formula (e) are shown below, but the present invention is not limited thereto.

UV-10: 2,4-dihydroxybenzophenone

UV-11: 2,2'-dihydroxy-4-methoxybenzophenone

UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone

UV-13: bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane)

In addition, a discotic compound such as a compound having 1,3,5-triazine ring is also preferably used as an ultraviolet absorber.

The first and second optical compensation layers (3, 5) in the present invention preferably contain two or more ultraviolet absorbers.

As the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used. Especially, a polymer-type ultraviolet absorber described in JP-A-6-148430 is preferably used.

The ultraviolet absorber may be added by adding an ultraviolet absorber to an alcohol such as methanol, ethanol or butanol, or an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane, or a mixed solvent thereof, May be added. Those which are not soluble in an organic solvent such as an inorganic powder are dispersed in an organic solvent and a cellulose ester using a dissolver or a sand mill, and then added to the dope.

The amount of the ultraviolet absorber to be used is not uniform depending on the kind of the ultraviolet absorber and the conditions of use. When the thickness of the optical compensation film (optical compensation layer (3, 5)) is 30 to 200 탆, 10 mass%, more preferably 0.6 mass% to 4 mass%.

(3.5) Antioxidant

Antioxidants are also known as deterioration inhibitors. When a liquid crystal image display device or the like is placed in a state of high humidity and high temperature, deterioration of the first and second optical compensation layers 3 and 5 as the optical compensation film may occur. The antioxidant is preferably contained in the optical compensation film because it has a role of retarding or preventing decomposition of the optical compensation film by, for example, halogen in the residual solvent amount in the optical compensation film or phosphoric acid of the phosphoric acid-based additive .

As such an antioxidant, a hindered phenol-based compound is preferably used, and examples thereof include 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexane Di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4- Di-t-butyl anilino) -1,3,5-triazine, 2,2-thio-diethylene bis [3- (3,5- Propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5 Di-t-butyl-4-hydroxybenzyl) -isocyanurate. Particularly, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t- butyl-4-hydroxyphenyl) propionate], triethylene glycol -Bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]. Further, a hydrazine-based metal inactive agent such as N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, -t-butylphenyl) phosphite may be used in combination.

The amount of these compounds to be added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm, in mass ratio with respect to the cellulose derivative.

(3.6) Fine particles

It is preferable that the first and second optical compensation layers (3, 5) in the present invention contain fine particles.

Examples of the inorganic particles used in the present invention include inorganic compounds such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, Magnesium and calcium phosphate. The fine particles include silicon, which is preferable in that turbidity is low, and silicon dioxide is particularly preferable.

The average particle diameter of the primary particles of the fine particles is preferably 5 to 400 nm, more preferably 10 to 300 nm. These particles may be mainly contained as secondary aggregates having a particle diameter of 0.05 to 0.3 탆, and it is also preferable that particles having an average particle diameter of 100 to 400 nm are contained as primary particles without aggregation. The content of these fine particles in the optical compensation films (3, 5) is preferably 0.01 to 1% by mass, particularly preferably 0.05 to 0.5% by mass. In the case of the optical compensation films (3, 5) having a multi-layer structure according to the covalent coating method, it is preferable that the surface contains fine particles in the added amount.

The fine particles of silicon dioxide are commercially available, for example, under the trade names AEROSIL R972, R972V, R974, R812, 200, 200V, 300, R202, OX50 and TT600 (manufactured by Nippon Aerosil Co., Ltd.) , Can be used.

Fine particles of zirconium oxide are commercially available, for example, under the trade names AEROSIL R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

Examples of the polymer include a silicone resin, a fluororesin, and an acrylic resin. Silicone resin is preferable, and it is particularly preferable to have a three-dimensional network structure. For example, Tospearl 103, Copper 105, Copper 108, Copper 120, Copper 145, Copper 3120 and Copper 240 ), And can be used.

Among them, Aerosil 200V and Aerosil R972V are particularly preferably used since they have a low effect of lowering the friction coefficient while keeping the turbidity of the optical compensation film low. In the optical compensation films (3, 5) used in the present invention, the coefficient of dynamic friction of at least one surface is preferably 0.2 to 1.0.

The various additives may be added to the dope as the cellulose ester-containing solution before film formation, or the additive solution may be separately prepared and added in-line. Particularly, in order to reduce the load on the filter medium, it is preferable that the fine particles are partially or entirely added in in-line.

When the additive solution is added in-line, it is preferable to dissolve a small amount of the cellulose ester in order to improve the mixing property with the dope. The amount of the cellulose ester is preferably 1 to 10 parts by mass, more preferably 3 to 5 parts by mass, based on 100 parts by mass of the solvent.

In order to perform inline addition and mixing in the present invention, for example, an inline mixer such as a static mixer (manufactured by TORAY ENGINEERING) or an SWJ (Toray static in-tube mixer high-mixer) is preferably used.

(3.7) Production method of optical compensation film

Next, a method for producing an optical compensation film as the first and second optical compensation layers (3, 5) in the present invention will be described.

The optical compensation film may be either a film produced by the solution casting method or a film produced by the melt casting method.

The production of the optical compensation film of the present invention can be carried out by a process comprising the steps of preparing a dope by dissolving a cellulose ester and an additive in a solvent, a step of softening on an endless metal support for infinitely moving the dope, A step of stretching or maintaining the width, a step of drying, and a step of winding the finished film.

The process for producing the dope will be described. Although the concentration of the cellulose ester in the dope is preferable because the drying load after the cellulose ester is flexible to the metal support can be reduced, if the concentration of the cellulose ester is too high, the load during filtration increases and the filtration accuracy deteriorates. The concentration compatible therewith is preferably 10 to 35 mass%, more preferably 15 to 25 mass%.

The solvent to be used in the dope may be used alone or in combination of two or more kinds. However, it is preferable to use a mixture of a cellulose ester ester and a poor solvent in view of production efficiency, and both of them are soluble in cellulose ester . A preferable range of the mixing ratio of the both agent and the poor solvent is 70 to 98% by mass for both the solvents and 2 to 30% by mass for the solvent. As the two-component solvent and the low-boiling solvent, the two solvents in which the cellulose ester to be used is solely dissolved are defined as the two solvents, and the one in which the solvent does not swell or dissolve is defined as the poor solvent. As a result, according to the average degree of acetalization (acetyl group substitution degree) of the cellulose ester, the two agents and the poor solvent are changed. For example, when acetone is used as the solvent, the acetate ester of the cellulose ester (acetyl group substitution degree 2.4), cellulose acetate In propionate, it is a biodegradable agent, and in acetic acid ester of cellulose (acetyl group substitution degree 2.8), it becomes an empty solvent.

There are no particular restrictions on the two agents used in the present invention, but organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate can be given. Particularly preferred are methylene chloride or methyl acetate.

The poor solvent used in the present invention is not particularly limited, and for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used. It is preferable that the dope contains 0.01 to 2% by mass of water. The solvent used for dissolving the cellulose ester is used by recovering the solvent removed from the film by drying in the film-forming step, and reusing the solvent. In some cases, an additive added to the cellulose ester in the recovering solvent, for example, a plasticizer, an ultraviolet absorber, a polymer, a monomer component and the like may be contained in a small amount, but if contained, they can be preferably recycled. It is possible.

As a method of dissolving the cellulose ester when preparing the above-described dope, a general method can be used. When heating and pressurization are combined, heating can be performed at a boiling point or more at normal pressure. It is preferable to stir and dissolve the solvent while heating at a temperature in the range that the solvent has boiling point or more at normal pressure and the solvent does not boil under pressure so as to prevent the generation of massive solids called gel or agglomerate. Further, a method in which a cellulose ester is mixed with a poor solvent, followed by wetting or swelling, followed by addition of a two-component agent and dissolution is also preferably used.

The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of raising the vapor pressure of the solvent by heating. The heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.

The heating temperature to which the solvent is added is preferably from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is excessively high, the pressure required becomes large and the productivity deteriorates. The heating temperature is preferably 45 to 120 占 폚, more preferably 60 to 110 占 폚, and even more preferably 70 to 105 占 폚. The pressure is also adjusted so that the solvent does not boil at the set temperature.

Or a cooling dissolution method is preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

Next, this cellulose ester solution is filtered using a suitable filter medium such as a filter paper. As the filter material, it is preferable that the absolute filtration accuracy is small in order to remove insolubles and the like. However, if the absolute filtration accuracy is too small, the filter material is liable to be clogged. Therefore, a filter material having an absolute filtration accuracy of 0.008 mm or less is preferable, a filter material of 0.001 to 0.008 mm is more preferable, and a filter material of 0.003 to 0.006 mm is more preferable.

The material of the filter medium is not particularly limited and a usual filter medium can be used. However, a plastic filter material such as polypropylene or Teflon (registered trademark) or a metal filter material such as stainless steel is preferable because the fiber does not fall off . It is preferable to remove and reduce impurities contained in the cellulose ester as a raw material by filtration, in particular, dew-point foreign substances.

The spot foreign material means a polarizing plate in which two polarizing plates are arranged in a crossed Nicols state and an optical film or the like is placed therebetween and light is irradiated from the side of one polarizing plate and the light from the opposite side (Foreign matter), and it is preferable that the number of wigs having a diameter of 0.01 mm or more is 200 pieces / cm ² or less. More preferably 100 pieces / cm ² or less, still more preferably 50 pieces / m ² or less, and particularly preferably 0 to 10 pieces / cm ² or less. It is also preferable that the luminescent point is 0.01 mm or less.

The filtration of the dope can be carried out by a usual method, but a method of filtration while heating at a temperature in the range of the boiling point of the solvent at atmospheric pressure or higher and the solvent not boiling under pressure is referred to as a difference in filtration pressure before and after filtration ) Is small. The preferred temperature is 45 to 120 占 폚, more preferably 45 to 70 占 폚, and still more preferably 45 to 55 占 폚.

The filtration pressure is preferably small. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

Here, the dope flexing will be described.

It is preferable that the metal support in the casting process is a mirror finished surface, and as the metal support, a stainless steel belt or a drum finishing the surface of the cast iron is preferably used. The width of the cast may be 1 to 4 m. The surface temperature of the metal support of the softening process is preferably from -50 DEG C to less than the boiling point of the solvent because the higher the temperature is, the higher the drying speed of the web can be. However, if too high, the web may be foamed or the planarity may deteriorate . The preferred support temperature is 0 to 40 占 폚, more preferably 5 to 30 占 폚. Alternatively, it is preferable that the web be gelled by cooling to peel off the drum in a state containing a large amount of residual solvent. The method of controlling the temperature of the metal support is not particularly limited, but there is a method of spraying hot air or cold air, or a method of bringing hot water into contact with the back surface of a metal support. The use of the hot water is preferable because heat is efficiently transferred, and the time until the temperature of the metal support becomes constant is short. In the case of using hot air, a wind having a temperature higher than a desired temperature may be used.

In order for the optical compensation film to exhibit good planarity, the amount of the residual solvent when peeling the web from the metal support is preferably from 10 to 150% by mass, more preferably from 20 to 40% by mass or from 60 to 130% Particularly preferably 20 to 30% by mass or 70 to 120% by mass.

In the present invention, the amount of the residual solvent is defined by the following equation.

Amount of residual solvent (mass%) = {(M-N) / N} 100

M is the mass of the sample taken from the web or film at any point during or after the production, and N is the mass after heating the M at 115 DEG C for 1 hour.

In the drying step of the optical compensation film, the web is preferably peeled off from the metal support and dried, and the amount of the residual solvent is preferably 1 mass% or less, more preferably 0.1 mass% or less, 0 to 0.01% by mass or less.

In the film drying process, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged in the upper and lower rolls) or a method in which the web is conveyed in a tenter method is used.

At this time, in the case of producing an optical compensation film as the first optical compensation layer 3, it is preferable to bond the shrinkable film to the dried cellulose-based resin film and shrink it while stretching.

In the case of producing an optical compensation film as the second optical compensation layer 5, biaxially stretching treatment is preferably performed.

In order to produce the optical compensation film of the present invention, it is particularly preferable to perform stretching in the transverse direction (transverse direction) by a tenter method of gripping both ends of the web with clips or the like. The peel strength is preferably 300 N / m or less.

The means for drying the web can be generally performed by hot air, infrared rays, heating rolls, microwaves or the like without any particular limitation, but it is preferable to conduct the air by hot air in terms of simplicity.

It is preferable that the drying temperature in the drying process of the web is increased stepwise at 40 to 200 ° C.

The film thickness of the optical compensation film is not particularly limited, but 10 to 200 탆 is used. Particularly, it is particularly preferable that the film thickness is 10 to 100 mu m. More preferably 20 to 60 占 퐉.

The optical compensation film of the present invention has a width of 1 to 4 m. Particularly preferably 1.4 to 4 m in width, and particularly preferably 1.6 to 3 m in width. If it exceeds 4 m, it becomes difficult to transport.

The liquid crystal molecules in the liquid crystal cell 4 are oriented in the thickness direction of the liquid crystal cell 4 in black display and the first and second optical compensation layers 3 and 5 are oriented in the thickness direction of the liquid crystal cell 4, nx1> nz1> ny1, nx2≥ny2> nz2 and DSP (Ro1) <1 <DSP (Rth2), the viewing angle is enlarged, the front contrast is improved, and the color shift when viewed from the oblique direction is prevented (See Examples).

In the first embodiment, the liquid crystal display device according to the present invention is described as the liquid crystal display device 1 shown in Fig. 1 (a). However, the liquid crystal display device shown in Fig. 1 (b) 1A). 1B, the first polarizer 2, the first optical compensation layer 3, the liquid crystal cell 4, and the second polarizer 2 are formed so as to extend from the viewing side toward the backlight side, The second optical compensation layer 5 and the second polarizer 6 are stacked in this order and the absorption axis 2J of the first polarizer 2 and the slow axis of the first optical compensation layer 3 The absorption axis 2J of the first polarizer 2 and the absorption axis 6J of the second polarizer 6 are orthogonal to each other and the slow axis 3J of the first optical compensation layer 3 becomes parallel And the absorption axis 6J of the second polarizer 6 are orthogonal to each other. 1B, the backlight is shown as the lower side in the figure, but it may be the upper side.

[Second Embodiment]

Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

2 (a) is a conceptual diagram showing a schematic configuration of another liquid crystal display device 1D according to the present invention.

As shown in this figure, the liquid crystal display 1D includes a first polarizer 2, a first optical compensation layer 3D, a liquid crystal cell 4, The compensating layer 5 and the second polarizer 6 in a laminated state in this order. The first optical compensation layer 3D has a biaxial film (base film) 30 and a liquid crystal layer 31 in this order from the viewing side to the backlight side.

More specifically, the first polarizer 2, the second polarizer 6 and the biaxial film 30 are arranged in parallel with the absorption axis 2J of the first polarizer 2 and the slow axis 30J of the biaxial film 30, And the absorption axis 2J of the first polarizer 2 and the absorption axis 6J of the second polarizer 6 are orthogonal to each other and the slow axis 30J of the biaxial film 30 and the second polarizer 6 are perpendicular to each other, So that the absorption axis 6J of the liquid crystal panel 6 is parallel. In Fig. 2, the backlight is shown as the lower side in the drawing, but may be the upper side.

(First optical compensation layer)

The first optical compensation layer 3D in this embodiment has a laminate structure including the biaxial film 30 and the liquid crystal layer 30 and satisfies nx1> nz1> ny1 and DSP (Ro1) <1 as a whole And is a so-called Z plate with a reverse wavelength dispersion. The first optical compensation layer 3D preferably has an in-plane retardation value Ro1 of 50 to 100 nm and an absolute value of retardation value Rth1 in the thickness direction of 0 nm to 20 nm.

The first optical compensation layer 3D is preferably in the form of a film though there is no limitation in its form. The thickness d of the film is preferably 40 to 100 mu m, more preferably 40 to 70 mu m.

<Biaxial Film>

The biaxial film 30 is a film having a refractive index satisfying nx> ny> nz. As the biaxial film 30, a cellulose resin film that is the same as the first optical compensation layer 3 in the first embodiment and subjected to stretching treatment may be used.

<Middle layer>

In the optical compensation layer 3D of the present invention, an intermediate layer (alignment film, not shown) for assisting the vertical alignment of the liquid crystal can be provided between the biaxial film 30 and the liquid crystal layer 31.

The intermediate layer of the present invention is composed of a transparent resin. The transparent resin is preferably a binder polymer having a saturated hydrocarbon chain or polyether chain as a main chain, and more preferably a binder polymer having a saturated hydrocarbon chain as a main chain.

Particularly preferred is a resin composition which is cured by crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams, or a resin composition comprising a crosslinking agent and a resin having a reactive site.

Examples of the curable resin include ultraviolet curable acrylate resins such as ultraviolet curable urethane acrylate resin, ultraviolet curable polyester acrylate resin, ultraviolet curable epoxy acrylate resin, ultraviolet curable polyol acrylate resin or ultraviolet curable epoxy resin Based resin is preferably used.

The ultraviolet curing type urethane acrylate resin is generally prepared by reacting a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer with 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (hereinafter, Acrylate), and 2-hydroxypropyl acrylate or other acrylate-based monomer having a hydroxyl group can be easily obtained by further reacting the monomer.

For example, those described in Japanese Patent Application Laid-Open No. 59-151110 can be used. For example, 100 parts of Shiko UV-7510B (manufactured by Nippon Kosei Kagaku Co., Ltd.) and Unidick 17-806 (manufactured by Dainippon Ink), and 1 part of Colonate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) Mixtures and the like are preferably used.

As ultraviolet curable polyester acrylate resins, polyester resins generally can be easily formed by reacting a 2-hydroxyethyl acrylate or 2-hydroxyacrylate monomer with a polyester polyol. ) 59-151112 can be used.

As specific examples of the ultraviolet curable epoxy acrylate resin, epoxy acrylate is used as an oligomer, and a reactive diluent and a photopolymerization initiator are added to the resin to react them. As disclosed in JP-A-1-105738 Can be used.

Specific examples of the UV curable polyol acrylate resin include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl modified Dipentaerythritol pentaacrylate, and the like.

Specific examples of the photopolymerization initiator of these curable resins include benzoin and derivatives thereof, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone,? -Amyloxime ester, thioxanthone, and derivatives thereof. It may be used together with a photosensitizer.

When an epoxy acrylate-based photopolymerization initiator is used, a sensitizer such as n-butylamine, triethylamine or tri-n-butylphosphine may be used.

The photopolymerization initiator or photosensitizer used in the curable resin composition is 0.1 to 25 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the composition.

As the acrylate resin, there may be mentioned methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane di Acrylate, 1,4-cyclohexyldimethyldiacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and the like.

KR-400, KR-410, KR-550, KR-566, KR-567 and BY-320B (manufactured by Asahi Denka Kogyo Co., Ltd.); 101, K-A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T- -102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Koei Chemical Industry Co., Ltd.); PHCX-9 (K-3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (Dainichiseika (Manufactured by Kagaku Kogyo Co., Ltd.); KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UCB Co., Ltd.); RC-5151, RC-5180, RC-5181 (manufactured by Daikin Industries, Ltd.) Manufactured by Ink Chemical Industry Co., Ltd.); Orex No. 340 Kriya (manufactured by Zukudo Coatings Co., Ltd.); RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries, Ltd.); SP-1509, SP-1507 (manufactured by Showa Kobunshi Co., Ltd.); NK hard B-420, NK ester A-DOG, NK ester A-DOC, MK-8060 (manufactured by Toagosei Co., Ltd.), RK-15C (made by Grace Japan K.K.), Aronix M- IBD-2E (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) and the like can be appropriately selected and used.

Examples of the other acrylic acid esters include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dioxane glycol acrylate, ethoxylated acrylate Alkyl-modified dipentaerythritol pentaacrylate, and the like.

Examples of the mixed composition of the crosslinking agent and the resin having a reactive site of the present invention include polyvinyl alcohol, glyoxal, gelatin and glyoxal.

The intermediate layer may contain a fluorine-acrylic copolymer resin. The fluorine-acrylic copolymer resin is a copolymer resin composed of a fluorine monomer and an acrylic monomer, particularly a block copolymer comprising a fluorine monomer segment and an acrylic monomer segment.

(Method for producing intermediate layer)

The intermediate layer is coated with a coating composition for forming an intermediate layer on a biaxial film 30 by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, an ink jet method, It is preferable to perform UV curing treatment.

The coating amount is suitably from 0.1 to 40 mu m as a wet film thickness, preferably from 0.5 to 30 mu m.

The average dry film thickness is 0.01 to 1 占 퐉, preferably 0.02 to 0.7 占 퐉.

As the light source for the UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp and the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of the active ray is usually 5 to 500 mJ / cm ² , preferably 5 to 150 mJ / cm ² .

In addition, when irradiating the active line, it is preferable to apply tension while applying a tensile force in the transport direction of the biaxial film 30, and more preferably, it is performed while imparting tensile force also in the width direction. The tensile force to be imparted is preferably 30 to 300 N / m.

The method of imparting tension is not particularly limited, and tension may be applied in the conveying direction on the back roll, or in the width direction or biaxial direction in the tenter. As a result, a film having better planarity can be obtained.

The coating composition for forming the intermediate layer may contain a solvent. Examples of the organic solvent contained in the coating composition include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) Esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers and other organic solvents may be appropriately selected or used in combination.

The organic solvent is preferably propylene glycol monoalkyl ether (1 to 4 carbon atoms in the alkyl group) or propylene glycol monoalkyl ether acetic ester (1 to 4 carbon atoms in the alkyl group). The content of the organic solvent is preferably 5 to 80% by mass in the coating composition.

<Liquid crystal layer>

The liquid crystal layer 31 satisfies the refractive index nz > nx = ny, and is a so-called positive C plate. The liquid crystal layer 31 preferably has the following characteristics.

0? Ro? 10

-500? Rth? -100

The liquid crystal layer 31 is formed by applying a liquid crystal material or a liquid crystal solution directly on the biaxial film 30 or on the intermediate layer and performing drying and heat treatment (also referred to as orientation treatment) And has a phase difference due to the rod-shaped liquid crystal aligned in the vertical direction.

Here, the orientation in the vertical direction means that the rod-like liquid crystal is in the range of 70 to 90 DEG (the vertical direction is 90 DEG) with respect to the film surface of the biaxial film 30 as the support.

The rod-shaped liquid crystal may be oriented by changing the orientation angle gradually even if it is oriented obliquely with respect to the biaxial film 30. [ Preferably in the range of 80 to 90 degrees.

This liquid crystal layer 31 is a phase difference layer formed of rod-like liquid crystals oriented in the vertical direction in which Ro is in the range of 0 to 10 nm and Rth is in the range of -500 to -100 nm. Further, Ro is more preferably in the range of 0 to 5 nm.

When the rod-shaped liquid crystal is aligned to form the liquid crystal layer 31, the above-mentioned intermediate layer (alignment film) coated with the vertical alignment agent in which the liquid crystal material is arranged in the vertical direction is used and the liquid crystal material is vertically aligned and fixed You can take a method.

In the case where the liquid crystal material itself is oriented in the vertical direction at the air interface, since the alignment regulating force reaches the interface opposite to the air interface, an orientation film is not particularly required and it is preferable from the viewpoint of simplifying the structure.

As a specific method for orienting the liquid crystal material vertically, there can be used a method of using an alignment film or the like comprising a crosslinked body of a block polymer composition containing a (meth) acrylic block copolymer as described in JP-A-2005-148473, Known methods such as a method using a vertical alignment film and a method using an air interface vertical alignment agent can be used as described in JP-A-2005-265889.

In order to set the liquid crystal layer 31 in the range of the characteristics of Ro and Rth, it is necessary to control the orientation of the rod-shaped liquid crystal layer, the film thickness control, the temperature during the ultraviolet curing, the tilt angle control, and the support (biaxial film 30) It is preferable to control the pretilt angle at the interface.

The liquid crystal layer 31 is formed by laminating a liquid crystal material that can become a liquid crystal phase at a predetermined temperature with predetermined liquid crystal regularity. The upper limit of the temperature representing the liquid crystal phase is not particularly limited as long as it is a temperature at which the cellulose ester film of the substrate is not damaged.

More specifically, a liquid crystal material which is liquid crystal phase at a temperature of 120 DEG C or lower, more preferably 100 DEG C or lower is appropriately used from the viewpoints of ease of control of process temperature and maintenance of dimensional accuracy. On the other hand, the lower limit of the temperature indicating the liquid crystal phase can be said to be a temperature at which the liquid crystal material can maintain the alignment state when it is used as a polarizing plate.

As the liquid crystal material used for the liquid crystal layer 31, a polymerizable liquid crystal material is preferably used. The polymerizable liquid crystal material can be polymerized by irradiation with a predetermined active radiation, and in the polymerized state, the vertical alignment state is fixed.

As the polymerizable liquid crystal material, any one of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer may be used, or they may be mixed with each other.

As the polymerizable liquid crystal material, a polymerizable liquid crystal monomer is suitably used because it has a high sensitivity at the time of orientation and is easy to align vertically.

Specific examples of the polymerizable liquid crystal monomer include a rod-like liquid crystalline compound (I) represented by the following formula (1) and a rod-like liquid crystalline compound (II) represented by the following formula (2). As the compound (I), a mixture of two or more kinds of compounds contained in the formula (1) may be used, or two or more of the compounds contained in the formula (2) may be used in combination as the compound (II). At least one of the compounds (I) and (II) may be used in combination.

In the formula (1) representing the compound (I), R ¹ and R ² each represent hydrogen or a methyl group, but from the range of the temperature range indicating the liquid crystal phase, it is preferable that R ¹ and R ² are all hydrogen.

X may be hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group or a nitro group, but is preferably chlorine or a methyl group.

The chain lengths of the alkylene groups as the spacer of the (meth) acryloyloxy group and the aromatic ring at both ends of the molecular chain of the compound (I) can be arbitrarily selected from the range of 2 to 12 However, it is preferably in the range of 4 to 10, more preferably in the range of 6 to 9.

In addition to the above, it is possible to appropriately select and use a polymeric liquid crystal oligomer or a known material conventionally proposed as a polymerizable liquid crystal polymer in the present invention.

For example, as the polymerizable rod-shaped liquid crystalline compound, there can be mentioned, for example, Makromol. Chem., 190, 2255 (1989), Advanced Materials 5, 107 (1993)], U.S. Patent Nos. 4683327, 5622648, 5770107, and WO95 / 22586 , Japanese Patent Application Laid-Open Nos. 95/24455, 97/00600, 98/23580, 98/52905, 1-272551, 6-16616, 7 -110469, 11-80081, 2001-328973, 2004-240188, 2005-99236, 2005-99237 Compounds described in Japanese Patent Application Laid-Open Nos. 2005-121827 and 2002-30042 can be used.

In the present invention, a photopolymerization initiator is used as needed in addition to the polymerizable liquid crystal material. When a polymerizable liquid crystal material is polymerized by electron beam irradiation, a photopolymerization initiator may not be required. In general, for example, in the case of curing by ultraviolet (UV) irradiation, a photopolymerization initiator is usually used for promoting polymerization.

Examples of the photopolymerization initiator include benzyl (also referred to as benzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-benzoyl- , Dimethylaminomethylbenzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3'-dimethyl-4-methoxybenzophenone, methyllobenzoylformate, 2-methyl-1- (4-methylthio) phenyl) -2-morpholinopropane- 2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl- 2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-di Isopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone Or the like can be mentioned 1-chloro-4-propoxy City Oak Santon.

The amount of the photopolymerization initiator added is generally from 0.01% to 20%, more preferably from 0.1% to 10%, and still more preferably from 0.5% to 5%, to the polymerizable liquid crystal material of the present invention have.

Further, in addition to the photopolymerization initiator, it is also possible to add a sensitizer within the range in which the object of the present invention is not impaired.

The thickness of the liquid crystal layer 31 in the present invention is preferably in the range of 0.1 탆 to 10 탆, more preferably in the range of 0.2 to 5 탆.

The polymerizable liquid crystal material is prepared by mixing a photopolymerization initiator, a sensitizer, and the like as necessary to prepare a composition for forming a liquid crystal layer, and coating the substrate on the substrate (biaxial film 30) to form a liquid crystal layer-forming layer.

As a method of forming the layer in which the orientation of the liquid crystal is fixed, for example, a method in which a dry film or the like is formed in advance and a layer in which the alignment of the liquid crystal is fixed is laminated on a substrate, or a method in which a liquid crystal composition is dissolved or melted, However, in the present invention, a solvent is added as a liquid crystal composition, a coating composition obtained by dissolving the other components is coated on the substrate, and the solvent is removed to form a layer in which the orientation of the liquid crystal is fixed . This is simpler in the process than other methods.

The solvent is not particularly limited as long as it is a solvent capable of dissolving the polymerizable liquid crystal material and the like and does not deteriorate the property of the transparent resin film. Specific examples thereof include benzene, toluene, xylene, n-butylbenzene, Hydrocarbons such as diethylbenzene and tetralin; Ethers such as methoxybenzene, 1,2-dimethoxybenzene and diethylene glycol dimethyl ether; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or 2,4-pentanedione; Esters such as ethyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate or? -Butyrolactone; Amide solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide or dimethylacetamide; Halogenated solvents such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichlorethylene, tetrachlorethylene, chlorobenzene or orthodichlorobenzene; alcohols such as t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cellosolve or butyl cellosolve; Phenols such as phenol, and para-chlorophenol, and the like can be used.

Solubility of a polymerizable liquid crystal material or the like may be insufficient only by using a single kind of solvent or the substrate (biaxial film 30) may be eroded as described above. However, this problem can be avoided by mixing two or more kinds of solvents.

Of the above solvents, preferred as the sole solvent are a hydrocarbon solvent and a glycol monoether acetate solvent. Preferred examples of the mixed solvent are a mixture system of ethers or ketones and glycols.

The concentration of the solution depends on the solubility of the polymerizable liquid crystal material or the like and the film thickness of the liquid crystal layer to be produced. Therefore, it is usually 1% to 60%, more preferably 3% to 40% % &Lt; / RTI &gt;

In the composition for forming a liquid crystal layer used in the present invention, other compounds may be added within the range not impairing the object of the present invention.

Examples of the compound to be added include polyester (meth) acrylate obtained by reacting a (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol with a monobasic acid or a polybasic acid; A polyurethane (meth) acrylate obtained by reacting a polyol group and a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; A bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolak type epoxy resin, a polycarboxylic acid polyglycidyl ester, a polyol polyglycidyl ether, an aliphatic or alicyclic epoxy resin, an amine epoxy resin, A photopolymerizable compound such as an epoxy (meth) acrylate obtained by reacting an epoxy resin such as an epoxy resin or a dihydroxybenzene type epoxy resin with (meth) acrylic acid, or a photopolymerizable compound having an acrylic group or a methacryl group, And onium salts and fluoroacrylate polymers described in Japanese Patent Application Laid-Open No. 2007-45993.

The amount of these compounds to be added to the composition for forming a liquid crystal layer of the present invention is selected within a range that does not impair the object of the present invention and is generally 40% or less of the composition for forming a liquid crystal layer of the present invention, Is 20% or less.

By the addition of these compounds, the curability of the liquid crystal material in the present invention is improved, the mechanical strength of the resulting liquid crystal layer is increased, and its stability is improved.

Further, a surfactant or the like may be added to the composition for forming a liquid crystal layer in which a solvent is blended to facilitate coating.

Examples of the surfactant which can be added include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides and polyamine derivatives; Polyoxyethylene-polyoxypropylene condensates, primary or secondary alcohol ethoxylates, alkylphenol ethoxylates, polyethylene glycols and esters thereof, sodium laurylsulfate, ammonium laurylsulfate, laurylsulfate amines, alkyl-substituted aromatic sulfonic acids Anionic surfactants such as salts, alkyl phosphates, aliphatic or aromatic sulfonic acid formalin condensates; Amphoteric surfactants such as lauryl amide propyl betaine and lauryl amino acetic acid betaine; Nonionic surfactants such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamines; Perfluoroalkyl ethylene oxide adducts, perfluoroalkyltrimethylammonium salts, perfluoroalkyl groups, hydrophilic group-containing oligomers, perfluoroalkyl-oligomer-containing oligomer purple, perfluoroalkyl groups, perfluoroalkyl groups, perfluoroalkyl groups, And fluoro surfactants such as urethane in which fluoroalkyl groups are contained.

The amount of the surfactant to be added varies depending on the type of the surfactant, the type of the liquid crystal material, the type of the solvent, and the type of the alignment film to which the solution is applied, but is preferably 10 ppm to 10% of the polymerizable liquid crystal material contained in the solution , More preferably from 100 ppm to 5%, and still more preferably from 0.1 to 1%.

Examples of the method for coating the liquid crystal layer forming composition include spin coating, roll coating, printing, dip coating, die coating, casting, bar coating, blade coating, A coating method or an extrusion coating method.

The method of removing the solvent after coating the composition for forming a liquid crystal layer is carried out by, for example, air drying, heat removal or vacuum depressurization, or a combination thereof. By removing the solvent, a layer in which the orientation of the liquid crystal is fixed is formed.

In the step of curing the polymerizable liquid crystal material, energy for curing the polymerizable liquid crystal material is imparted, and thermal energy may be applied, but usually by irradiation with ionizing radiation capable of causing polymerization.

If necessary, the polymerization initiator may be contained in the polymerizable liquid crystal material. The ionizing radiation is not particularly limited as long as it is a radiation capable of polymerizing a polymerizable liquid crystal material. Ultraviolet light or visible light is generally used from the viewpoint of ease of apparatus and the like, and light having a wavelength of 150 to 500 nm is preferable, More preferably 250 to 450 nm, and still more preferably 300 to 400 nm.

In the present invention, a method of irradiating ultraviolet rays (UV) as active radiation and generating radicals from a polymerization initiator in ultraviolet rays to perform radical polymerization is preferable. Since the method of using UV as the active radiation is an established technique, application to the present invention is easy, including the polymerization initiator to be used.

Examples of the light source for irradiating the ultraviolet ray include a low pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), a high pressure discharge lamp (high pressure mercury lamp, metal halide lamp), or a short arc discharge lamp (ultra high pressure mercury lamp, Mercury xenon lamp), and the like.

Among them, the use of a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, or the like is recommended. The irradiation intensity may be appropriately adjusted in accordance with the composition of the polymerizable liquid crystal material used for forming the layer to which the orientation of the liquid crystal is fixed and a little of the photopolymerization initiator.

The orientation fixation step by irradiation with actinic radiation may be performed at a treatment temperature in the step of forming the liquid crystal layer formation layer, that is, at a temperature condition where the polymerizable liquid crystal material becomes a liquid crystal phase, or at a temperature lower than the liquid crystal phase You can do it.

According to the liquid crystal display device 1D as described above, the same effects as those of the first embodiment can be obtained, and the first optical compensation layer 3D can be made of the biaxial film 30 and the liquid crystal layer 31 of the positive C plate The magnitude of the phase difference to be given to the optical compensation layer can be remarkably reduced in order to achieve the viewing angle enlarging effect as compared with the case where the first optical compensation layer is composed of a single layer. Specifically, in the case where the first optical compensation layer is composed of a single layer, it is necessary to give a very large retardation value of the retardation value Ro? 275 to the optical compensation layer in order to obtain the effect of enlarging the viewing angle, In the compensation layer 3D, a retardation value equal to or less than 1/2 of the retardation value Ro = 50 to 100 is applied to the entire optical compensation layer 3D, thereby achieving a viewing angle magnification effect. Therefore, unlike the case where the first optical compensation layer is constituted by a single layer, it is possible to prevent the optical compensation layer from amplifying the influence of the slight optical axis deviation in the plane, so that the phase difference dispersion can be reduced and the front contrast can be kept high (See Examples).

In the second embodiment, the liquid crystal display device according to the present invention is described as the liquid crystal display device 1D shown in Fig. 2A. However, the liquid crystal display device shown in Fig. 2B 1E). Here, in the liquid crystal display 1E of FIG. 2B, the first polarizer 2, the liquid crystal layer 31 of the first optical compensation layer 3D, and the biaxial The film 30, the liquid crystal cell 4, the second optical compensation layer 5 and the second polarizer 6 are stacked in this order and the absorption axis 2J of the first polarizer 2 The slow axis 30J of the biaxial film 30 becomes parallel and the absorption axis 2J of the first polarizer 2 and the absorption axis 6J of the second polarizer 6 are orthogonal and the biaxial film 30 and the absorption axis 6J of the second polarizer 6 are orthogonal to each other. 2 (b), the backlight is shown as the lower side in the drawing, but the upper side may also be used.

It is needless to say that the present invention is not limited to the first and second embodiments described above, but can be appropriately modified and improved.

For example, the liquid crystal display device of the present invention is not limited to the configurations shown in Figs. 1 and 2 and may include other members. For example, a color filter (not shown) may be provided between the liquid crystal cell 4 and the polarizers 2, . Further, the surface of the protective film of the polarizers 2 and 6 may be subjected to an anti-reflection treatment or a hard coat. In addition, a conductive member provided with conductivity may be used. Further, when used as a transmission type, a backlight having a light source such as a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission device, or an electroluminescent device can be disposed on the backside. In this case, the arrangement of the backlight may be the upper side of FIG. 1 and FIG. 2, or the lower side. A reflection type polarizing plate, a diffusing plate, a prism sheet or a light guide plate may be disposed between the liquid crystal cell 4 and the backlight. As described above, the liquid crystal display of the present invention may be of a reflective type. In this case, it is sufficient to arrange only one polarizing plate on the viewing side, and the liquid crystal cell 4 may be arranged on the back surface of the liquid crystal cell 4, A reflective film is disposed on the inner surface of the glass substrate 41. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell side.

[Example]

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited thereto.

&Lt; Preparation of optical compensation films Z1 to Z9 &

Optical compensation films Z1 to Z9 as shown in the following Table 1 were prepared as samples of the first optical compensation film 3 in the above embodiment.

(Preparation of a mixture of cellulose esters)

Cellulose ester A (cellulose acetate propionate) 100 parts by mass

Additive 1 10 parts by mass

300 parts by mass of methylene chloride

Ethanol 52 parts by mass

And the solution was completely dissolved while heating and stirring. Thereafter, the solution was poured into an Azumi filter paper No. 1 manufactured by Azumi Kashi Co., Ltd. 24 to prepare a cellulose ester mixture. This mixture was filtered with Fine Mat NF manufactured by Nippon Seisen Co., Ltd.

However, the above-mentioned cellulose ester A is a cellulose ester having an acetyl group substitution degree of 1.6 and a propionyl group substitution degree of 0.9 as shown in the following Table 2. The above-mentioned additive 1 is a sugar ester compound represented by the following compound 3 as shown in Table 3 below.

(Preparation of diluted silicon dioxide dispersion)

10 parts by mass of Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.)

(Average diameter of primary particles: 16 nm, apparent specific gravity: 90 g / l)

Ethanol 80 parts by mass

The resulting mixture was stirred with a dissolver for 30 minutes and then dispersed with Manton-Gaulin to prepare a silicon dioxide dispersion. The liquid turbidity after dispersion was 200 ppm. 80 parts by mass of methylene chloride was added to the dispersion of silicon dioxide while stirring, and the mixture was stirred with a dissolver for 30 minutes to prepare a silicon dioxide dispersion diluted solution.

(Preparation of Dope Liquid 1)

10 parts by mass of a silicon dioxide-dispersed diluent was added to 100 parts by mass of the cellulose ester mixture thus obtained, and the mixture was stirred to prepare Dope Liquid 1.

(Production of Base Film A1 of Optical Compensation Film Z1)

A belt flexible device was used and the dope liquid 1 was uniformly softened to a stainless steel band support at a temperature of 35 DEG C and a width of 1800 mm. The solvent was evaporated until the amount of the residual solvent in the stainless steel band support reached 100% and peeled off from the stainless steel band support. The solvent of the web of the peeled cellulose ester film was evaporated at 55 占 폚 and stretched to 1.40 times in the width direction by using a tenter while heating at 140 占 폚 to 160 占 폚. The residual solvent at the start of the stretching was 15%. Thereafter, the drying was terminated while conveying the drying zone at 130 캜 to a number of rolls, knurling was carried out at both ends of the film at a width of 15 mm and an average height of 10 탆, and the core was wound at an initial tension of 220 N / m and a final tension of 110 N / To obtain a base film (biaxial film) A1 of an optical compensation film Z1 having a dry film thickness of 60 mu m.

(Production of base films A2 to 5, 8 and 9 of optical compensation films Z2 to 5, 8 and 9)

As shown in Table 1, the dope liquid was prepared in substantially the same manner as in the base film A1 except that the cellulose ester species, the additive species, the additive amount, the film thickness, and the draw ratio in the width direction were changed, Base films A2 to 5, 8 and 9 of optical compensation films Z2 to 5, 8 and 9 were produced.

In Table 1, &quot; B &quot; and &quot; C &quot; in the column "resin" refer to the cellulose esters B and C in Table 2, and C specifically represents the average of ε-caprolactone grafted per 1 mol of glucose unit (DS) of the graft chain (grafted caprolactone) was 0.3, the average polymerization degree (DPn) of the? -Caprolactone of the graft chain was 5.4, the average degree of substitution DS of the hydroxyl group OH) of 0.3 was used. The term "additive 2" in the "additive species" column refers to the additive 2 (acrylic compound) in Table 3 and specifically refers to an acrylic compound that is synthesized as described below.

(Synthesis of acrylic compound)

In a glass flask equipped with a stirrer, two dropping funnels, a gas introducing tube and a thermometer, 40 g of the mixture of monomers Xa and Xb in the kind and ratio (molar composition ratio) shown in Table 4, 2 g of mercaptopropionic acid as a chain transfer agent and 30 g of toluene were charged And the temperature was raised to 90 占 폚. Thereafter, 60 g of the mixture of the monomers Xa and Xb of the kind and ratio (molar composition ratio) shown in Table 4 was dropped from the one dropping funnel over 3 hours, and 0.4 g of azobisisobutyronitrile 0.4 g was added dropwise over 3 hours. Thereafter, 0.6 g of azobisisobutyronitrile dissolved in 56 g of toluene was further added dropwise over 2 hours, and the reaction was further continued for 2 hours to obtain Polymer X. Polymer X obtained was a solid at room temperature. The weight average molecular weight of Polymer X is shown in Table 4 according to the following measurement method.

In Table 4, MMA and HEA are abbreviations of the following compounds, respectively.

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

(Weight average molecular weight measurement)

Measurement of the weight average molecular weight was performed using gel permeation chromatography.

The measurement conditions are as follows.

Solvent: methylene chloride

Column: Shodex K806, K805, and K803G (connected by using three connectors manufactured by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: Standard polystyrene STK A calibration curve with 13 samples of standard polystyrene (manufactured by Tosoh Corporation) Mw = 1000000 to 500 was used. 13 The samples are used at almost equal intervals.

&Lt; Preparation of Optical Compensation Film Z1 >

An intermediate layer and a liquid crystal layer were formed on the base film A1 obtained as described above to produce an optical compensation film Z1 as shown in Table 1 above.

(Formation of intermediate layer)

Urethane acrylate oligomer 25 parts by mass

(UV-7510B, manufactured by Nippon Kosei Kagaku Co., Ltd.)

Propylene glycol monomethyl ether 290 parts by mass

685 parts by mass of isopropyl alcohol

Photopolymerization initiator 0.05 part by mass

(Lucirin TPO (manufactured by BASF))

This coating solution was coated on the base film A1 with wire bar # 3, dried at 80 DEG C for 30 seconds, and then irradiated with ultraviolet ray 120 mJ / mm for 10 seconds to form an intermediate layer. The film thickness of the intermediate layer after drying was 0.5 탆.

(Formation of liquid crystal layer (anisotropic layer)) [

20 parts by mass of ultraviolet polymerizable liquid crystal material

(UCL018, manufactured by Dainippon Ink and Chemicals, Incorporated)

80 parts by mass of propylene glycol monomethyl ether acetate

Photopolymerization initiator 0.04 parts by mass

(Lucirin TPO (manufactured by BASF))

Hindered amine 0.02 parts by mass

LS-765 (manufactured by SANKYO LIFE TECHNICAL CO., LTD.)

Vertical alignment agent 0.03 parts by mass

(X-22-161A, manufactured by Shin-Etsu Silicone Co., Ltd.)

The polymerizable liquid crystal layer coating liquid was coated on the intermediate layer by a die coater. The resultant was heated and dried at 80 캜 for 1 minute until the temperature of the liquid crystal layer reached 65 캜, and then rapidly cooled to 28 캜 to align the liquid crystal material.

It was also confirmed in advance that the ultraviolet polymerizable liquid crystal compound had a solid-liquid crystal phase transition temperature of 23 占 폚 and a liquid crystal-isotropic liquid phase transition temperature of 70 占 폚.

After aligning the liquid crystal material, the liquid crystal layer was irradiated with ultraviolet rays of 250 mJ / mm at an oxygen concentration of 0.2% and a temperature of 28 캜 for 10 seconds to cure the polymerizable liquid crystal composition to form a liquid crystal layer. The thickness of the liquid crystal layer was 1.2 mu m.

&Lt; Preparation of optical compensation films Z2 to 4, 8, and 9 >

Optical compensation films Z2 to 4, 8 and 9 were produced in substantially the same manner as in the optical compensation film Z1 except that the base films A2 to 4, 8 and 9 were used and the liquid crystal film thickness was changed as shown in the above-mentioned Table 1 Respectively.

&Lt; Production of optical compensation film Z5 >

As shown in the above-mentioned Table 1, the base film A5 was directly used as the optical compensation film Z5.

&Lt; Preparation of optical compensation film Z6 >

A pressure-sensitive adhesive layer (thickness: 15 占 퐉) was provided on both sides of the film A6 prepared in the same manner as the base film A2 except that the stretching magnification in the width direction was 1.01 times and the film thickness was 150 占 퐉. Trade name &quot; TREFAN BO2873 &quot;). Thereafter, the film was stretched 1.5 times in the longitudinal direction in an air circulating oven maintained at 180 ° C with the film length direction maintained by a roll stretching machine, and the shrinkable film was peeled together with the acrylic pressure-sensitive adhesive layer to prepare an optical compensation film Z6.

&Lt; Production of Optical Compensation Film Z7 >

Sensitive adhesive layer (thickness: 15 mu m) was applied on both sides of ZEONOA ZF-14-100 (average refractive index = 1.52, Tg = 136 DEG C, Ro = 3.0 nm, Rth = 5.0 nm, (Trade name &quot; TREFAN BO2873 &quot;, manufactured by Toray Industries, Inc.). Thereafter, the stretched film was stretched in the longitudinal direction at 1.38 times in the air circulating oven at 146 캜 while maintaining the longitudinal direction of the film by a roll stretching machine, and after stretching, the stretching film was peeled off together with the acrylic pressure-sensitive adhesive layer to produce an optical compensation film Z7 .

&Lt; Production of optical compensation films C1 to C8 &

Optical compensation films C1 to C8 as shown in Table 5 below were prepared as samples of the second optical compensation film 5 in the above-described embodiment.

Concretely, in the same manner as in the production of the substrate film A1, except that the cellulose ester species, the additive species, the additive amount and the film thickness were changed, and the film was stretched in the longitudinal direction by applying the transporting tension after the transverse stretching in the tenter, Compensation films C1 to C8 were prepared. The additive species in Table 5 are as shown in Table 3, and the DSP value rise first indicates the aromatic terminal polyester compound 18 and the DSP value increasing agent indicates the triazine compound.

&Lt; Evaluation of optical compensation film &

&Lt; Measurement of retardation values Ro and Rth >

Retardation values of optical compensation films Z1 to Z9 and C1 to C8 were measured using an automatic birefringence index meter (Cobra-21ADH, manufactured by Oji Keisoku KK).

More specifically, the optical compensation film was subjected to three-dimensional refractive index measurement at 10 points at a wavelength of 590 nm under the environment of 23 DEG C and 55% RH to obtain an average value of the refractive indices nx, ny and nz, The retardation value Ro in the in-plane direction and the retardation value Rth in the thickness direction were calculated. The results are shown in Table 6 below.

Ro = (nx-ny) xd

Rth = {(nx + ny) / 2-nz} xd

Nx is the index of refraction in the direction of the slow axis in the film plane, ny is the index of refraction in the fast axis direction in the film plane, and nz is the refractive index in the thickness direction of the film And d represents the thickness (nm) of the film.

The optical compensation films Z1 to Z4, Z6, Z8 and Z9 according to the present invention satisfy Ro> 0 and -Ro / 2 <Rth <Ro / 2, respectively, from the retardation values Ro1 and Rth1 of the first optical compensation layer in Table 6, 2, it can be seen that nx1> nz1> ny1 (: Equation 1) is satisfied.

Further, since the optical compensation films C1 to C6 according to the present invention have Ro? 0 and Rth > Ro / 2 from the retardation values Ro2 and Rth2 of the second optical compensation layer, nx2? 2). &Lt; / RTI &gt;

It can be seen that the optical compensation layer used in the liquid crystal display devices 1 to 8 of the present invention satisfies DSP (Ro1) <1 <DSP (Rth2) (Equation 3) as wavelength dispersibility.

&Lt; Production of polarizer plate &

The polyvinyl alcohol film having a thickness of 120 탆 was uniaxially stretched (temperature: 110 캜, stretching magnification: 5 times). This was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and then immersed in an aqueous solution of 68 캜 comprising 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer.

Optical Compensation Films Z1 to 9 or Optical Compensation Films C1 to 8 and a Konica Minolta Tact KC4UY (a cellulose ester film manufactured by Konica Minolta Opto) were placed on the back surface side of the polarizer according to the following Steps 1 to 5, Were bonded as protective films to produce polarizers Z11 to 19 and C11 to C18. However, for the optical compensation films Z1 to 4, 8, and 9, the base film side was bonded to the polarizer side so that the polarizer side (liquid crystal layer side is opposite to the polarizer).

Step 1: A film (optical compensation film, cellulose ester film) was immersed in a 2 mol / l sodium hydroxide solution at 60 占 폚 for 90 seconds, followed by washing with water and drying to obtain a saponified film on the side bonded to the polarizer.

Step 2: The polarizer was immersed for 1 to 2 seconds in a polyvinyl alcohol bonding preparation (tank) having a solid content of 2% by mass.

Step 3: In step 2, excess glue adhered to the polarizer was gently wiped off, and this was sandwiched between the optical compensation film treated in step 1 and the cellulose ester film.

Step 4: The laminate laminated in Step 3 was bonded at a pressure of 20 to 30 N / cm ² and at a conveying speed of about 2 m / min.

Step 5: The sample bonded in Step 4 was dried for 2 minutes in a dryer at 80 캜 to prepare polarizers Z 11 to 19 and C 11 to 18.

<< Fabrication of Liquid Crystal Display Device >>

A polarizing plate on both sides of a commercially available 32-type MVA type liquid crystal television (AQUOS32AD5 by Sharp, registered trademark of AQUOS) was peeled off, and the prepared polarizing plates Z11 to 19, C11 to 18 were combined (1) to (11) were manufactured. At this time, the direction of the polarizing plate was such that the side of the optical compensation film (the side opposite to the Konica Minolta Tact KC4UY) was on the liquid crystal cell side, and the absorption axis was oriented in the same direction as the polarizing plate previously bonded at the time of purchase.

The following evaluations were made using the liquid crystal display devices (1) to (11) produced as described above.

&Lt; Evaluation of liquid crystal display device &

&Lt; Evaluation of viewing angle &

The backlight of each liquid crystal display device was continuously lit for one week in an environment of 23 DEG C and 55% RH, and then the viewing angle was measured. The ratio of the luminance of the black display to that of the white display in the direction of the azimuth angles of 45 deg., 135 deg., 225 deg., 315 deg. And the tilt angle of 70 deg. By the EZ-Contrast 160D manufactured by ELDIM was measured, Respectively. The measurement results were evaluated according to the following criteria, and the results are shown in Table 6 above. In this evaluation standard, &quot; DELTA &quot; means that it is practically acceptable and &quot; x &quot; means that it is out of the allowable range in practical use.

?: 100 < A

?: 50 <A? 100

×: A 50

<Front Contrast>

The backlight of each liquid crystal display device was turned on in an environment of 23 캜 and 55% RH, and the luminance from the normal direction of the display screen of white display and black display was measured. The ratio was used as the frontal contrast, Evaluation was made as shown in Table 6 above. For the measurement, CS-2000 manufactured by Konica Minolta Sensing Co., Ltd. was used. Further, when the front contrast exceeds 1000, it is an excellent liquid crystal display device. In this evaluation standard, &quot; DELTA &quot; means that it is practically acceptable and &quot; x &quot; means that it is out of the allowable range in practical use.

Front contrast = (luminance of white display measured from the normal direction of the display device) / (luminance of black display measured from the normal direction of the display)

?: 1000 < front contrast

?: 750 <front contrast? 1000

DELTA: 500 < front contrast &lt;

X: Front contrast ≤ 500

&Lt; Evaluation of color shift when viewed from oblique direction >

With respect to each liquid crystal display device, the black display state in the dark room was visually confirmed from the oblique direction by a plurality of people and evaluated according to the following criteria, as shown in Table 6 above. In this evaluation standard, &quot; DELTA &quot; means that it is practically acceptable and &quot; x &quot; means that it is out of the allowable range in practical use.

◎: 0 out of 10 admits coloration

○: 1 or 2 out of 10 people recognized coloration

△: 3 to 5 out of 10 people recognized coloration

X: 5 to 10 out of 10 people recognized coloration

<Overall evaluation>

From the above results, unlike the liquid crystal display devices 9 to 11 in the comparative examples, the liquid crystal display devices 1 to 8 as the embodiments of the present invention exhibit a wide viewing angle, an improved frontal contrast, Prevention of the color shift is simultaneously achieved, and it was found that it is excellent.

Considering this point, the Rth of the rod-shaped liquid crystal in the VA mode liquid crystal cell is negative and its wavelength dispersion is positive. Light leakage of such liquid crystal cell (light due to the liquid crystal cell having a retardation in the thickness direction) It is considered that an optical compensation layer of a C plate having a positive Rth and positive wavelength dispersion like a liquid crystal cell is required. On the other hand, in order to compensate the light leakage of the polarizer (light leakage due to the fact that the transmission axes of the two polarizers are not orthogonal when viewed from the oblique direction), it is desirable to obtain the same compensation effect at each wavelength, It is considered that the optical compensation layer of the Z plate of the inverse wavelength dispersion in which the retardation becomes large is suitable. Therefore, according to the configuration of the present invention in which the optical compensation layer of the C plate having the positive wavelength dispersion and the optical compensation layer of the Z plate of the reverse wavelength dispersion are combined, the compensation of the light leakage caused by the liquid crystal cell and the polarizing plate It is presumed that the color shift, the viewing angle, and the frontal contrast in the case of viewing from the oblique direction are both possible.

1, 1A, 1D, 1E: liquid crystal display
2: first polarizer
3, 3D: first optical compensation layer
4: liquid crystal cell
5: Second optical compensation layer
6: Second polarizer
30: biaxial film (cellulose-based resin layer)
31: liquid crystal layer

Claims (6)

A first optical compensation layer, a liquid crystal cell, a second optical compensation layer, and a second polarizer in this order, at least a first polarizer,
Wherein the first and second optical compensation layers satisfy the following formulas (1) to (7)
Wherein the liquid crystal cell is in a vertically aligned (VA) mode.
&Quot; (1) &quot;
nx1>nz1> ny1
&Quot; (2) &quot;
nx2? nny2> nz2
&Quot; (3) &quot;
DSP (Ro1) <1 <DSP (Rth2)
(Where nx1 is the refractive index in the slow axis direction in the plane of the first optical compensation layer, ny1 is the refractive index in the fast axis direction in the plane of the first optical compensation layer, and nz1 is the refractive index in the thickness direction of the first optical compensation layer Nx2 is the refractive index in the slow axis direction in the plane of the second optical compensation layer, ny2 is the refractive index in the fast axis direction in the plane of the second optical compensation layer, and nz2 is the refractive index in the thickness direction of the second optical compensation layer Refractive index of the first optical compensation layer, Ro1 represents the in-plane retardation value of the first optical compensation layer represented by the following formula (8-1), Rth2 represents the retardation value of the second optical compensation layer in the thickness direction In-plane retardation value Ro1 of the first optical compensation layer measured at a wavelength of 480 nm as a wavelength dispersion value of the in-plane retardation value Ro1 of the first optical compensation layer, In-plane Rita Day measured at 630 nm (Rth2) is a wavelength dispersion value of the retardation value Rth2 in the thickness direction of the second optical compensation layer, and the retardation value Rth2 of the second optical compensation layer measured at a wavelength of 480 nm is And a retardation value Rth2 measured at a wavelength of 630 nm)
Equation (8-1)
Ro1 = (nx1-ny1) xd1
Equation (9-2)
Rth2 = {(nx2 + ny2) / 2-nz2} xd2
(Where d1 represents the thickness (nm) of the first optical compensation layer, d2 represents the thickness (nm) of the second optical compensation layer, and Ro1 and Rth2 are values measured at a wavelength of 590 nm, respectively)
&Quot; (4) &quot;
Ro1 = 50 to 100 [nm]
Equation (5)
| Rth1 | = 0 to 20 [nm]
&Quot; (6) &quot;
Ro2 = 0 to 20 [nm]
&Quot; (7) &quot;
Rth2 = 200 to 350 [nm]
(Where Rth1 denotes a retardation value in the thickness direction of the first optical compensation layer represented by the following equation (9-1) and Ro2 denotes a retardation value in a thickness direction of the second optical compensation layer represented by the following equation (8-2) Respectively, and Ro2 and Rth1 are values measured at a wavelength of 590 nm, respectively)
Equation (8-2)
Ro2 = (nx2-ny2) xd2
&Quot; (9-1) &quot;
Rth1 = {(nx1 + ny1) / 2-nz1} xd1 The liquid crystal display device according to claim 1, wherein the first optical compensation layer comprises a cellulose-based resin layer. The optical element according to claim 1 or 2, wherein the first optical compensation layer comprises at least a cellulose-based resin layer and a liquid crystal layer,
The above-mentioned cellulose-
Wherein the liquid crystal layer is disposed closer to the first polarizer than the liquid crystal layer,
Plane retardation, and the slow axis is orthogonal to the absorption axis of the first polarizer. The optical element according to claim 1 or 2, wherein the first optical compensation layer comprises at least a cellulose-based resin layer and a liquid crystal layer,
The above-mentioned cellulose-
Wherein the liquid crystal layer is disposed closer to the liquid crystal cell than the liquid crystal layer,
Plane retardation with respect to the absorption axis of the first polarizer, and the slow axis is parallel to the absorption axis of the first polarizer. The optical information recording medium according to claim 1 or 2, wherein the second optical compensation layer
And a cellulose ester resin layer containing a DSP value raising agent. delete

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