KR20110133036A - Liquid crystal display apparatus - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device which enlarges the viewing angle, improves front contrast, and prevents color shift when viewed from an oblique direction. The liquid crystal display device 1 of 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 formulas 1 to 3, and the liquid crystal molecules in the liquid crystal cell 4 are black liquid crystal cells 4 at the time of black display. In the thickness direction.
<Equation 1>
nx1>nz1> ny1
&Quot; (2) &quot;
nx2≥ny2> nz2
<Equation 3>
DSP (Ro1) <1 <DSP (Rth2)

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY APPARATUS}

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 inserted into a glass plate, and two polarizing plates provided on both sides thereof, and each polarizing plate is called a polarizer (polarizing film, polarizing film). ) Is attached to two optical films (polarizing plate protective film or optical compensation film). Further, in such a liquid crystal display device, various methods such as VA (Virtical Alignment) mode, IPS (In-Place-Switching) mode, TN (Twisted Nematic) mode have been developed, and among these, the VA mode is displayed. Due to its high speed and excellent front contrast, it is widely employed in large screen liquid crystal TVs and the like.

Here, in the VA mode liquid crystal display device, since the long axis of the liquid crystal material is oriented perpendicular to the substrate surface when no voltage is applied, almost full black display becomes possible when viewed from the direction perpendicular to the substrate, and high contrast can be realized. It has the feature that it can.

On the other hand, when the liquid crystal material is vertically aligned, there is a problem that coloring occurs in the black display or the contrast decreases due to light leakage when viewed from the inclined direction. There are mainly two causes for this problem, one of which is due to the fact that the liquid crystal layer itself used for the liquid crystal cell has a phase difference (also referred to as retardation) in the thickness direction. In addition, the other two polarizers in which the liquid crystal cell is sandwiched are arranged with cross nicol (so that the transmission axis is orthogonal). The transmission axes of these polarizers are orthogonal when viewed from the front, but they are shifted from the apparent 90 degrees when viewed from the oblique direction. do.

For 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) are nx> ny> nz. The technique which arrange | positions two biaxial films on both sides of a liquid crystal cell, and aims at enlargement of a viewing angle is proposed. However, in this structure, although it is cost-effective as using two sheets of the same kind of film, sufficient viewing angle enlargement effect was not acquired.

Accordingly, 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 arranged on a polarizing plate to further increase the viewing angle (for example, , Patent Documents 1 and 2).

However, in the technique described in Patent Documents 1 and 2, although the viewing angle is enlarged, other optical performances that are particularly important in recent years, in particular, the color shift when viewed from the front contrast and the oblique direction, are not considered at all. Further improvement is desired.

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

An object of the present invention is to provide a liquid crystal display device capable of enlarging the viewing angle, improving front contrast, and preventing color shift when viewed from an oblique direction.

The present inventors earnestly researched about the above-mentioned problem, and since the conventional Z plate was manufactured by heat shrinkage of polycarbonate, cycloolefin, etc., it was possible to manufacture only what has a constant wavelength dispersion (DSP> 1). It has been found that using cellulose of wavelength dispersion (DSP <1), a Z plate of reverse wavelength dispersion can be produced. Moreover, although the said patent document 2 states that it is preferable that C plate is reverse wavelength dispersion and Z plate is constant wavelength dispersion with respect to wavelength dispersion value DSP, the present inventors earnestly researched, and Z plate of positive wavelength dispersion and positive When the liquid crystal cell was sandwiched by the C plate of the wavelength dispersion, it was found that the color shift in the case viewed from the oblique direction can be reduced, and the viewing angle and the front contrast can be improved. In addition, even when using a Z plate of inverse wavelength dispersion, when the Z plate is composed of a single layer, a very large phase difference with a retardation value of Ro? 275 can be given to the Z plate in order to show the viewing angle enlargement effect. Since it is necessary, the Z plate amplifies the influence of a slight deviation of the optical axis in the plane and causes a decrease in front contrast. When the Z plate is a laminated structure of a liquid crystal layer functioning as a biaxial film and a positive C plate, When the phase difference of 1/2 or less of the retardation value Ro = 50-100 is applied to the whole Z plate, the viewing angle enlargement effect can be exhibited, the phase difference unevenness can be reduced, and the front contrast can be kept high. It was.

In view of the above, according to the 1st aspect of this invention, in a liquid crystal display device,

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

The first and second optical compensation layers satisfy the following Equations 1 to 3,

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

<Equation 2>

nx2≥ny2> nz2

&Quot; (3) &quot;

DSP (Ro1) <1 <DSP (Rth2)

Where nx1 is a refractive index in the in-plane slow axis direction of the first optical compensation layer, ny1 is a refractive index in the fast axis direction in the plane of the first optical compensation layer, and nz1 is a refractive index in the thickness direction of the first optical compensation layer. Nx2 is a refractive index in the in-plane slow axis direction of the second optical compensation layer, ny2 is a refractive index in the in-plane fastening direction of the second optical compensation layer, and nz2 is a thickness direction of the second optical compensation layer. Refractive indexes are respectively represented, Ro1 represents an in-plane retardation value of the first optical compensation layer represented by Equation 8-1, and Rth2 represents a thickness direction of the second optical compensation layer represented by Equation 9-2. DSP (Ro1) is a wavelength dispersion value of the in-plane retardation value Ro1 of the first optical compensation layer, and the in-plane retardation value Ro1 of the first optical compensation layer measured at a wavelength of 480 nm. In-plane retardation measured at 630 nm DSP (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. Divided by the retardation value Rth2 measured at a wavelength of 630 nm.)

<Equation 8-1>

Ro1 = (nx1-ny1) × d1

<Equation 9-2>

Rth2 = {(nx2 + ny2) / 2-nz2} × d2)

(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 resin layer.

In addition, in the liquid crystal display device of the present invention,

The first optical compensation layer satisfies Equations 4 and 5,

The second optical compensation layer preferably satisfies Equations 6 and 7 below.

<Equation 4>

Ro1 = 50-100 [nm]

<Equation 5>

| Rth1 | = 0-20 [nm]

<Equation 6>

Ro2 = 0-20 [nm]

<Equation 7>

Rth2 = 200-350 [nm]

(Where Rth1 represents a retardation value in the thickness direction of the first optical compensation layer represented by Equation 9-1 below, and Ro2 represents an in-plane ritata of the second optical compensation layer represented by Equation 8-2 shown below. Indicates a datum value, and Ro2 and Rth1 are measured at a wavelength of 590 nm, respectively.)

<Equation 8-2>

Ro2 = (nx2-ny2) × d2

<Equation 9-1>

Rth1 = {(nx1 + ny1) / 2-nz1} × d1)

In addition, in the liquid crystal display device of the present invention,

The first optical compensation layer includes at least a cellulose resin layer and a liquid crystal layer,

The cellulose resin layer,

It is arrange | positioned at the said 1st polarizer side rather than the said liquid crystal layer,

In addition to having an in-plane retardation, the slow axis is preferably perpendicular to the absorption axis of the first polarizer.

In addition, in the liquid crystal display device of the present invention,

The first optical compensation layer includes at least a cellulose resin layer and a liquid crystal layer,

The cellulose resin layer,

It is arranged in the liquid crystal cell side than the liquid crystal layer,

It is preferable that the slow axis is parallel to the absorption axis of the first polarizer while having in-plane retardation.

In addition, in the liquid crystal display device of the present invention,

The second optical compensation layer,

It is preferable that it consists of a cellulose resin layer containing a DSP value increasing 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 during black display, and the first and second optical compensation layers are nx1> nz1> ny1, nx2≥ny2> nz2, and DSP (Ro1). Since <1 <DSP (Rth2) is satisfied, the viewing angle can be enlarged, the front contrast can be improved, and the color shift in the case viewed from the oblique direction can be prevented (see Example).

1 is a conceptual diagram showing a schematic configuration of a liquid crystal display device according to the present invention.
It is a conceptual diagram which shows schematic structure of the modification of the liquid crystal display device which concerns on this invention.

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

[First Embodiment]

FIG. 1A is a conceptual diagram illustrating an example of the liquid crystal display device 1 in the first embodiment.

As shown in this figure, the liquid crystal display device 1 is a liquid crystal display device in VA mode, and has a first polarizer 2, a first optical compensation layer 3, and a liquid crystal cell from the viewing side toward the backlight side. (4), the second optical compensation layer 5, and the second polarizer 6 are stacked in this order. More specifically, the first, second polarizers 2 and 6 and the first optical compensation layer 3 are formed on the absorption axis 2J of the first polarizer 2 and the ground of the first optical compensation layer 3. The axis 3J is orthogonal, the absorption axis 2J of the first polarizer 2 and the absorption axis 6J of the second polarizer 6 are orthogonal, and the slow axis 3J of the first optical compensation layer 3 is perpendicular. ) And the absorption axis 6J of the second polarizer 6 are arranged in parallel. In addition, although the backlight is shown as the lower side in the figure in FIG. 1, you may make it the upper side. In addition, in this specification, "parallel" and "orthogonal" mean that it exists in the range of less than an exact angle +/- 10 degrees. It is preferable that the error with an exact angle is less than +/- 5 degrees, and, as for this range, it is more preferable that it is less than +/- 2 degrees. In addition, in this specification, a slow axis means the direction in which refractive index becomes largest.

(1) liquid crystal cell

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

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

As the liquid crystal material of the liquid crystal layer 40, dielectric anisotropy is negative, and a nematic liquid crystal material having a refractive index anisotropy Δn = 0.0815 and a dielectric anisotropy of Δε = -4.5 or the like can be used. Although there is no restriction | limiting in particular about the thickness d of the liquid crystal layer 40, When using the nematic liquid crystal material mentioned above, it can set to about 3.5 micrometers. However, since the brightness at the time of white display changes depending on the magnitude of the product Δn · d of the thickness d and the refractive index anisotropy Δn, it is preferable to set the Δn · d to be in the range of 0.2 to 0.5 μm to obtain the maximum brightness. .

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

Moreover, when it is set as a multi-domain structure, it is also advantageous to adjust the orientation of the liquid crystal molecule of the boundary region between each domain.

Here, the multi-domain structure means a structure in which one pixel of the liquid crystal display is divided into a plurality of regions. For example, since the liquid crystal molecules are inclined at the time of white display in VA mode, the birefringence of the liquid crystal molecules when viewed from the inclined direction is different in the oblique direction and in the opposite direction, and a difference occurs in the luminance and color tone. The domain structure is preferable because the viewing angle characteristics of luminance and color tone are improved. Specifically, by constituting and averaging each pixel into two or more regions (preferably 4 or 8) where the initial alignment states of the liquid crystal molecules differ from each other, it is possible to reduce the deviation of luminance and color tone depending on the viewing angle. In addition, the same effect can be obtained even if each pixel is comprised from two or more different areas from which the orientation direction of a liquid crystal molecule changes continuously in a voltage application state. In order to form a plurality of regions having different alignment directions of liquid crystal molecules in one pixel, for example, a method of providing slits in the electrodes, forming protrusions, changing the direction of the electric field, or biasing the electric field density may be used. Can be. The number of divisions may be increased in order to obtain a uniform viewing angle in all directions, but by setting it as 4 divisions or 8 divisions or more, a substantially uniform viewing angle is obtained. In particular, at eight divisions, the polarizing plate absorption axis can be set at any angle, which is preferable. At the region boundary of each domain, liquid crystal molecules tend to be difficult to respond. In the normally black mode such as the VA mode, black display is maintained, so that a decrease in luminance becomes a problem. Therefore, it is possible to add a chiral agent to a liquid crystal material and to make the boundary area between domains small. On the other hand, since the white display state is maintained in the normally white mode, the front contrast is lowered. Therefore, what is necessary is just to provide light shielding layers, such as a black matrix which covers the area | region.

(2) first and second polarizers

The 1st, 2nd polarizers 2 and 6 are optical elements which let only the light of a polarization plane of a predetermined direction pass, and are manufactured by the conventionally well-known general method. Here, as a typical polarizer known at present, there exists a polyvinyl alcohol-type polarizing film, More specifically, the thing which dyed an iodine to the polyvinyl alcohol-type film, and dyed a dichroic dye was mentioned. As such a polarizer, the polyvinyl alcohol aqueous solution is formed into a film, this is uniaxially stretched and dyed, or after dyeing, it is uniaxially stretched, Preferably the thing which carried out the durability treatment with the boron compound is used.

Usually, both sides are clamped by a TAC film etc. as a protective layer. It is preferable to bond together the at least one surface of the polarizer produced by alkali saponification process of the back surface of a TAC film, and immersed and stretched in the said iodine solution using the fully saponified polyvinyl alcohol aqueous solution. The other side may use the said TAC film, and may use the film which has another polarizing plate protective function. Commercially available cellulose ester films (e.g., Konica Minolta Tack KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC4UE, KC8UY, KC4UY, KC12UR, KC4FR, or higher Konica Minolta Opto is also preferably used).

In the structure of this invention, the 1st, 2nd polarizers 2 and 6 are each supported by 2 TAC films, and are attached to the 1st, 2nd optical compensation layers 3 and 5 via an adhesive bond layer. Although bonding may be performed, it is preferable to be bonded directly to the optical compensation layers 3 and 5 without a TAC film from a thinning, member reduction, and optical compensation viewpoint.

(3) first and second optical compensation layers

It is preferable that the 1st and 2nd optical compensation layers 3 and 5 satisfy | fill the following formulas 1-3, and are a film form from a viewpoint of handling (henceforth an optical compensation film 3 and 5). More preferably, the following Equations 4 to 7 are satisfied.

&Quot; (1) &quot;

nx1> nz1> ny1

<Equation 2>

nx2≥ny2> nz2

&Quot; (3) &quot;

DSP (Ro1) <1 <DSP (Rth2)

<Equation 4>

Ro1 = 50-100 [nm]

<Equation 5>

| Rth1 | = 0-20 [nm]

<Equation 6>

Ro2 = 0-20 [nm]

<Equation 7>

Rth2 = 200-350 [nm]

Here, "nx" represents a refractive index in the in-plane slow axis direction of the optical compensation layer, "ny" represents a refractive index in the in-plane fast axis direction of the optical compensation layer, and "nz" represents a refractive index in the thickness direction of the optical compensation layer, respectively. "Ro" and "Rth" are retardation values obtained by the following equations (8) and (9). In addition, in each formula, the subscript "1" and "2" represent the value regarding the 1st optical compensation layer 3 and the 2nd optical compensation layer 5, respectively. In addition, these values are the values measured at the wavelength of 590 nm. In addition, the value of each refractive index can be calculated | required in 23 degreeC and 55% RH environment, for example using KOBRA-21ADH (Oji Keisokuki Co., Ltd.) and Axo scan (made by AXOMETRICS).

<Equation 8>

Ro = (nx-ny) × d

&Quot; (9) &quot;

Rth = {(nx + ny) / 2-nz} × d)

According to these equations (8) and (9), when the refractive index is nx> nz> ny, Ro> 0, and -Ro / 2 <Rth <Ro / 2 are satisfied. Conversely, Ro> 0 and -Ro / 2. In the case of <Rth <Ro / 2, it is understood that nx> nz> ny is satisfied. In addition, when nx≥ny> nz, Ro≥0 and Rth> Ro / 2 are satisfied. On the contrary, when Ro≥0 and Rth> Ro / 2, nx≥ny> nz is satisfied. .

In addition, "DSP (Ro1)" in above-mentioned Formula (3) is a wavelength dispersion value of the in-plane phase difference of the 1st optical compensation layer 3, Specifically, the 1st optical compensation layer 3 measured at wavelength 480nm. ) Is a value obtained by dividing the retardation value Ro of) by the retardation value Ro measured at a wavelength of 630 nm. In addition, "DSP (Rth2)" is a wavelength dispersion value of the thickness direction phase difference of the 2nd optical compensation layer 5, Specifically, the retardation value Rth of the 2nd optical compensation layer 5 measured by wavelength 480nm is measured. It is the value divided by the retardation value Rth measured at the wavelength of 630 nm. These wavelength dispersion values DSP become DSP> 1 for positive wavelength dispersion and DSP <1 for negative (inverse) 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 reverse wavelength dispersion Z plate. The first optical compensation layer 3 preferably has an in-plane retardation value Ro1 of 50 to 100 nm, and an absolute value of the retardation value Rth1 in the thickness direction is 0 nm to 20 nm.

Here, in order to give the performance of nx1> nz1> ny1 and DSP (Ro1) <1 to the 1st optical compensation layer 3, the shrinkable film is bonded to the cellulose resin film which has reverse wavelength dispersion property, as mentioned later, It is preferable to shrink while stretching. Moreover, it is also preferable to use the biaxial film which extended | stretched this resin as a base material, to apply a liquid crystal layer on it, and to dry and fix it. These are explained in detail together with the description of FIG.

Although the form of the 1st optical compensation layer 3 is not restrict | limited, It is preferable that it is a film. 40-100 micrometers is preferable and, as for the thickness d of a film, 40-70 micrometers is more preferable.

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

Although there is no limitation in particular as a cellulose ester used for the 1st optical compensation layer 3, Preferably it is a C2-C22 carboxylic acid ester as a cellulose ester, Ester of an aromatic carboxylic acid may be especially preferable. Lower fatty acid esters having 6 or less carbon atoms. Moreover, you may use the cellulose ester resin which graft-polymerized (epsilon) -caprolactone to cellulose ester resin as disclosed in Unexamined-Japanese-Patent No. 2008-197561.

The acyl group bonded to the hydroxyl group may be linear, branched, or may form a ring. Moreover, another substituent may substitute. In the case of the same degree of substitution, since the birefringence decreases when the carbon number is large, the carbon number is preferably selected from acyl groups having 2 to 6 carbon atoms. It is preferable that carbon number as said cellulose ester is 2-4, and it is more preferable that carbon number is 2-3.

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

In addition, the butyryl group which forms butyrate may be linear or may be branched. Especially as a cellulose ester used preferably in this invention, a cellulose acetate, a cellulose acetate butyrate, a cellulose acetate propionate, a cellulose acetate phthalate is used preferably.

As cellulose esters other than cellulose acetate phthalate which are preferable for this invention, it is preferable to satisfy following formula (101) and (102) simultaneously.

<Equation 101>

2.0≤X + Y≤3.0

Equation 102

0≤Y≤1.5

Wherein X is the degree of substitution of the acetyl group, Y is the degree of substitution of the propionyl group or the butyryl group, or mixtures thereof.

Moreover, in order to acquire the optical characteristic according to the objective, you may mix and use resin in which substitution degree differs. As a mixing ratio, 10: 90-90: 10 (mass ratio) are preferable.

Among these, cellulose acetate propionate is especially used preferably. In cellulose acetate propionate, it is 1.0 <= <= <= 2.5, and 0.1 <= <========= ++ <= + == 3.0 are preferable. The measuring method of substitution degree of an acyl group can be measured according to ASTM-D817-96.

The number average molecular weight of the cellulose ester used for this invention is preferable because the mechanical strength of the film from which the range of 60000-300000 is obtained is strong. In addition, the thing of 70000-200000 is used preferably.

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

Measurement conditions are as follows.

Solvent: Methylene Chloride

Column: Shodex K806, K805, K803G (used by connecting 3 Showa Denko Co., Ltd.)

Column temperature: 25 ° C

Sample concentration: 0.1% by mass

Detector: RI model 504 (made by GL Science)

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

Flow rate: 1.0ml / min

Calibration curve: Standard polystyrene STK Standard polystyrene (manufactured by Tosoh Corporation) Mw = 1000000 to 500 using a calibration curve with 13 samples. 13 samples are used at substantially equal intervals.

Although there is no limitation in particular as a cellulose which is a raw material of the cellulose ester used for this invention, Cotton linter, wood pulp, kenaf, etc. are mentioned. In addition, the cellulose ester obtained from it can be mixed and used in arbitrary ratios, respectively.

Cellulose esters, such as cellulose acetate phthalate of this invention, can be manufactured by a well-known method. Specifically, the method described in JP 10-45804 A can be synthesized by reference.

(3.2) second optical compensation layer

As described above, the second optical compensation layer 5 satisfies nx2? Ny2> nz2 and 1 <DSP (Rth2), and becomes a so-called negative wavelength dispersion negative C plate. Further, the second optical compensation layer 5 is preferably Ro2 = 0 to 20 and Rth2 = 200 to 350.

Here, in order to make the retardation value of the 2nd optical compensation layer 5 into said numerical range, it is preferable to perform biaxial stretching process. In addition, when this 2nd optical compensation layer 5 contains a cellulose ester, in order to make residual distortion as small as possible in the process of heat processing and extending | stretching in the range of about +10 degreeC of glass transition points of a cellulose ester, The film produced in the conveyance direction (length direction) and its orthogonal direction (width direction) about 1.1 times-1.5 times, or produced by solution casting | flow_spread is carried out in the conveyance direction and its orthogonal direction in the state in which 2-100 mass% of residual solvents remain. It is preferable to stretch about 1.1 to 1.7 times.

In this 2nd optical compensation layer 5, it is preferable to control in-plane nonuniformity. For that purpose, it is preferable to precisely control the balance of the stretching temperature and the stretching ratio, and to control the stretching portion (clip of tenter, etc.) independently on both sides of the optical compensation layer 5. Such control can be achieved by adjusting the clip position and adjusting the draw temperature and the draw ratio with respect to the stress of the clip.

Although the shape of the 2nd optical compensation layer 5 is not restrict | limited, It is preferable that it is a film. The thickness of the film is 40 to 200 mu m, preferably 40 to 120 mu m.

(3.2.1) Cellulose resin used in the second optical compensation layer

There is no restriction | limiting in particular as a cellulose ester used for the 2nd optical compensation layer 5, Other than the cellulose ester resin which graft-polymerized (epsilon) -caprolactone to cellulose ester resin among the cellulose esters which can be used for the said 1st optical compensation layer 3 Resin of can be used.

(3.2.2) DSP value increasing agent

It is preferable to make the retardation value into said numerical range for this 2nd optical compensation layer 5, and to use a DSP value increasing agent in order to acquire the effect of this invention.

The DSP synergist refers to a compound in which the DSP (Rth) increases 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 general formula (II) disclosed in Japanese Patent Laid-Open No. 2007-249180 can be used.

<Formula II>

(In Formula II, R <^12> respectively independently represents an aromatic ring or a heterocyclic ring which has a substituent in at least one of an ortho position, a meta position, and a para position, X <^11> respectively independently represents a single bond or -NR <^13> -. R ¹³ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group, or a heterocyclic group)

In addition, you may use a disk shaped compound as a DSP synergist.

As a disk shaped compound, the compound which has at least 2 aromatic ring can be used.

In the present specification, the "aromatic ring" includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring.

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

Aromatic heterocycles are generally unsaturated heterocycles. It is preferable that an aromatic hetero ring is a 5-membered ring, a 6-membered ring, or a 7-membered ring, and it is more preferable that it is a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the largest number of double bonds. As a hetero atom, a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, and a nitrogen atom is especially preferable. Examples of aromatic hetero rings include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring, Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

As the aromatic ring, 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, a pyrazine ring and a 1,3,5-triazine ring are preferable. In particular, the 1,3,5-triazine ring is preferably used. Specifically, for example, the compound disclosed in Japanese Patent Laid-Open No. 2001-166144 is preferably used as a disk-shaped compound.

It is preferable that the number of the aromatic rings which the said disk shaped compound has is 2-20, It is more preferable that it is 2-12, It is further more preferable that it is 2-8, It is most preferable that it is 2-6.

The bonding relationship between the two aromatic rings can be classified into (a) forming a condensed ring, (b) directly bonding with a single bond, and (c) bonding through a linking group. Cannot be formed). The coupling relationship may be any of (a) to (c).

Examples of the condensed ring (condensed ring of two or more aromatic rings) in (a) include an indene ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthalene ring, a biphenylene ring, a naphthacene ring, Pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indoliazine ring, benzoxazole ring, benzothiazole ring, benzoimidazole ring, benzotriazole ring, purine ring, indazole ring, chromen ring, quinoline Ring, isoquinoline ring, quinoline ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothia Pentane ring, phenoxatin 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.

It is preferable that the single bond of (b) is a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded by two or more single bonds to form an aliphatic ring or a non-aromatic heterocycle between the two aromatic rings.

It is preferable that the linking group of (c) couple | bonds with the carbon atom of 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 the coupling group which consists of a combination is shown below. In addition, the relationship of left and right of the example of the following coupler may be reversed. c1: -CO-O- c2: -CO-NH- c3: -alkylene-O- c4: -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-c11: -alkylene-CO-O-alkylene- O-CO-alkylene-c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-c13: -O-CO-alkylene-CO-O-c14: -NH- CO-alkenylene- c15: -O-CO-alkenylene-

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

Examples of the substituent include halogen atom (F, Cl, Br, I), hydroxyl group, carboxyl group, cyano group, amino group, nitro group, sulfo group, carbamoyl group, sulfamoyl group, ureido group, alkyl group, alkenyl group, Alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamide group, aliphatic substituted amino group, aliphatic substituted carbamoyl group, Aliphatic substituted sulfamoyl groups, aliphatic substituted ureido groups and non-aromatic heterocyclic groups are included.

It is preferable that carbon number of an alkyl group is 1-8. It is preferable that it is a chain alkyl group rather than a cyclic alkyl group, and a linear alkyl group is especially preferable. The alkyl group may further have a substituent (eg, 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 methyl group, ethyl group, n-butyl group, n-hexyl group, 2-hydroxyethyl group, 4-carboxybutyl group, 2-methoxyethyl group and 2-diethylaminoethyl group Included.

It is preferable that carbon number of an alkenyl group is 2-8. It is preferable that it is a linear alkenyl group rather than cyclic alkenyl group, and a linear alkenyl group is especially preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, allyl group, and 1-hexenyl group.

It is preferable that carbon number of an alkynyl group is 2-8. It is preferable that it is a linear alkynyl group rather than cyclic alkynyl group, and a linear alkynyl group is especially preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include an ethynyl group, 1-butynyl group and 1-hexynyl group.

It is preferable that carbon number of an aliphatic acyl group is 1-10. Examples of aliphatic acyl groups include acetyl groups, propanoyl groups and butanoyl groups.

It is preferable that carbon number of an aliphatic acyloxy group is 1-10. Examples of aliphatic acyloxy groups include acetoxy groups.

It is preferable that carbon number of an alkoxy group is 1-8. The alkoxy group may further have a substituent (for example, an alkoxy group). Examples of the alkoxy group (including a substituted alkoxy group) include methoxy group, ethoxy group, butoxy group and methoxyethoxy group.

It is preferable that carbon number of an alkoxycarbonyl group is 2-10. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

It is preferable that carbon number of the alkoxycarbonylamino group is 2-10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

It is preferable that carbon number of an alkylthio group is 1-12. Examples of the alkylthio group include methylthio group, ethylthio group and octylthio group.

It is preferable that carbon number of an alkylsulfonyl group is 1-8. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.

It is preferable that carbon number of an aliphatic amide group is 1-10. Examples of aliphatic amide groups include acetamide groups.

It is preferable that carbon number of an aliphatic sulfonamide group is 1-8. Examples of aliphatic sulfonamide groups include methanesulfonamide groups, butanesulfonamide groups and n-octanesulfonamide groups.

It is preferable that carbon number of an aliphatic substituted amino group is 1-10. Examples of the aliphatic substituted amino group include a dimethylamino group, diethylamino group and 2-carboxyethylamino group.

It is preferable that carbon number of an aliphatic substituted carbamoyl group is 2-10. Examples of aliphatic substituted carbamoyl groups include methylcarbamoyl groups and diethylcarbamoyl groups.

It is preferable that carbon number of an aliphatic substituted sulfamoyl group is 1-8. Examples of the aliphatic substituted sulfamoyl group include a methyl sulfamoyl group and a diethyl sulfamoyl group.

It is preferable that carbon number of an aliphatic substituted ureido group is 2-10. Examples of aliphatic substituted ureido groups include methylureido groups.

Examples of the nonaromatic heterocyclic group include a piperidino group and a morpholino group.

It is preferable that the molecular weight of the DSP synergist which consists of a disk shaped compound is 300-800.

In the present invention, a rod-shaped compound having a linear molecular structure can be preferably used in addition to the disk-shaped compound described above. The linear molecular structure means that the molecular structure of the rod-shaped compound is linear in the thermodynamic most stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, molecular orbital calculation software (for example, WinMOPAC2000, manufactured by Fujitsu Co., Ltd.) is used for molecular orbital calculation, and the structure of the molecule in which the heat of production of the compound is the smallest can be obtained. The linear structure means that in the thermodynamic most stable structure calculated and calculated as described above, the angle formed by the main chain in the molecular structure is 140 degrees or more.

As the rod-shaped compound, one having at least two aromatic rings is preferable, and as the rod-shaped compound having at least two aromatic rings, a compound represented by the following general formula (103) is preferable.

<Formula 103>

Ar ¹ -L ¹ -Ar ²

(In 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. The heterocycle of the aromatic heterocyclic group is generally unsaturated. It is preferable that an aromatic hetero ring is a 5-membered ring, a 6-membered ring, or a 7-membered ring, and it is more preferable that it is a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the largest number of double bonds. As a hetero atom, a nitrogen atom, an oxygen atom, or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.

As an aromatic ring of an aromatic group, 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 are preferable, and a benzene ring is especially preferable. Do.

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group (eg, methylamino group, ethylamino group, butyl) Amino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (e.g., N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group), sulfamoyl group , Alkyl sulfamoyl group (e.g., N-methyl sulfamoyl group, N-ethyl sulfamoyl group, N, N-dimethylsulfamoyl group), ureido group, alkyl ureido group (e.g., N-methyl ureido group, N, N -Dimethylureido group, N, N, N'-trimethylureido group, alkyl group (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, t -Amyl group, cyclohexyl group, cyclopentyl group), alkenyl group (e.g. vinyl group, allyl group, hexenyl group), alkynyl group (e.g. ethynyl group, butynyl group) Groups (e.g. formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (e.g. acetoxy group, butyryloxy group, hexanoyloxy group, lauryloxy group), alkoxy group (e.g. Methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, heptyloxy group, octyloxy group, aryloxy group (eg phenoxy group), alkoxycarbonyl group (eg methoxycarbonyl group, ethoxycarbonyl group, pro Foxoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (e.g. phenoxycarbonyl group), alkoxycarbonylamino group (e.g. butoxycarbonylamino group, hexyloxycarbonylamino group), alkyl thi Ogi (e.g., methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group), arylthio group (e.g., phenylthio group), alkylsulfonyl group (e.g., Methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butyl sulfonate Phonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group), amide group (e.g. acetamide group, butylamide group, hexylamide group, laurylamide group) and non-aromatic heterocyclic group (e.g. morpholinyl group) And pyridinyl groups) are included.

As a substituent of a substituted aryl group and a substituted aromatic heterocyclic group, 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, an alkoxy group, an alkylthio group And alkyl groups are preferred.

The alkyl portion and alkyl group of the alkylamino group, the alkoxycarbonyl group, the alkoxy group and the alkylthio group may further have a substituent. Examples of the substituent of the alkyl moiety and the alkyl group include halogen atom, hydroxyl, carboxyl, cyano, amino, alkylamino group, nitro, sulfo, carbamoyl, alkylcarbamoyl group, sulfamoyl, alkylsulfamoyl group, ureido , Alkylureido group, alkenyl group, alkynyl group, acyl group, acyloxy group, acylamino group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkylsulfo Neyl group, amide group and non-aromatic heterocyclic group are included. As a substituent of an alkyl part and an alkyl group, a halogen atom, hydroxyl, amino, an alkylamino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, and an alkoxy group are preferable.

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

The alkylene group may have a cyclic structure. As a cyclic alkylene group, cyclohexylene is preferable and 1, 4- cyclohexylene is especially preferable. As a linear alkylene group, it is preferable that it is a linear alkylene group rather than the alkylene group which has a branch.

It is preferable that carbon number of an alkylene group is 1-20, More preferably, it is 1-15, More preferably, it is 1-10, Especially preferably, it is 1-8, Most preferably, it is 1-6. .

 It is preferable that an alkenylene group and an alkynylene group have a linear structure rather than a cyclic structure, and it is more preferable to have a linear structure than the linear structure which has a branch.

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, and most preferably Is 2 (vinylene or ethynylene).

It is preferable that arylene group has 6-20 carbon atoms, More preferably, it is 6-16, More preferably, it is 6-12.

In the molecular structure of Formula (103), it is preferable that the angle which Ar <^1> and Ar <^2> form by interposing L <^1> is 140 degree or more.

As a rod-shaped compound, the compound represented by following General formula (104) is more preferable.

<Formula 104>

Ar ¹ -L ² -XL ³ -Ar ²

(In Formula 104, Ar ¹ And Ar ^{2 Are} each independently an aromatic group, the definition and examples of the aromatic group is the same as Ar ¹ and Ar ² of Formula 103)

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

It is preferable that an alkylene group has a linear structure rather than a cyclic structure, and it is more preferable to have a linear structure rather than the linear structure which has a branch.

It is preferable that carbon number of an alkylene group is 1-10, More preferably, it is 1-8, More preferably, it is 1-6, Especially preferably, it is 1-4, 1 or 2 (methylene or ethylene) Is most preferred.

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

In formula (104), X is 1,4-cyclohexylene, vinylene or ethynylene.

As a specific example of the compound represented by General formula (103) or (104), the compound of Unexamined-Japanese-Patent No. 2004-109657 can be mentioned.

In addition, a preferable compound is shown below.

In the ultraviolet absorption spectrum of a solution, you may use together 2 or more types of rod-shaped compounds whose maximum absorption wavelength ((lambda) max) is shorter than 250 nm.

The rod-shaped compound can be synthesized by the method described in the literature. As literature, Mol. Cryst. Liq. Cryst., Vol. 53, p. 229 (1979), vol. 89, p. 93 (1982), vol. 145, p. 111 (1987), vol. 170, p. 43 (1989), J. Am. Chem. Soc., Vol. 113, p. 1349 (1991), vol.118, p. 5346 (1996), vol. 92, p. 1582 (1970), J. Org. Chem., 40, 420 (1975), Tetrahedron, 48, 16, 3437 (1992).

(3.3) additives

In order to acquire the effect of this invention, the 1st, 2nd optical compensation layers 3 and 5 mentioned above can contain an additive as needed. The additive is not particularly limited, but preferably aromatic terminal polyester compounds, sugar ester compounds, (meth) acrylic compounds, polyhydric carboxylic acid ester compounds, glycolate compounds, phthalic acid ester compounds, fatty acid ester compounds, Polyhydric alcohol ester compounds, polyester plasticizers and the like.

(3.3.1) Aromatic Terminal Polyester Compounds

In this invention, the aromatic terminal polyester type compound represented by following formula (I) can be used.

<Formula I>

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

Wherein B is an arylcarboxylic acid residue, 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, and A is 4 to 12 carbon atoms. Alkylene dicarboxylic acid residues or aryldicarboxylic acid residues having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)

In the formula (I), an arylcarboxylic acid residue represented by B and an alkylene glycol residue or an oxyalkylene glycol residue or an aryl glycol residue represented by G, an alkylenedicarboxylic acid residue represented by A or an aryldicarboxylic acid It is comprised from a residue and is obtained by reaction similar to a normal polyester type compound.

Examples of the arylcarboxylic acid component of the aromatic terminal polyester compound used in the present invention include benzoic acid, para tert-butyl benzoic acid, ortho toluic acid, metatoluic acid, paratoluic acid, dimethyl benzoic acid, ethyl benzoic acid, and normal propyl. Benzoic acid, amino benzoic acid, acetoxy benzoic acid, and the like, and these may be used as one kind or a mixture of two or more kinds, respectively.

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

In particular, alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of its excellent compatibility with cellulose esters.

Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal polyester compound include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like. Silver may be used as one kind or a mixture of two or more kinds.

As an alkylene dicarboxylic acid component of 4 to 12 carbon atoms of an aromatic terminal polyester type compound, for example, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecane dicarboxylic acid And the like, each of which is used as one kind or a mixture of two or more kinds.

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

It is preferable that n is 1 or more and 100 or less, and, as for the aromatic terminal polyester type compound used by this invention, it is preferable that number average molecular weights are 300-1500, More preferably, it is the range of 400-1000.

Moreover, the acid value 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.

It is preferable to contain 0.5-30 mass% of aromatic terminal polyester type compounds represented by General formula (I) of this invention with respect to a cellulose ester.

Hereinafter, although the specific compound of the aromatic terminal polyester type compound which can be used for this invention is shown, this invention is not limited to this.

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

(3.3.2) Sugar Ester Compounds

The 1st, 2nd optical compensation layer 3, 5 of this invention has at least 1 sort (s) or 12 or less types of a pyranose structure or a furanose structure, and all or part of the OH group of the structure is carried out. It is good also as what contains the esterified ester compound (sugar ester compound).

As a ratio of esterification, it is preferable that it is 70% or more of the OH group which exists in a pyranose structure or a furanose structure.

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

As an example of the ester compound of this invention, although the following are mentioned, for example, this invention is not limited to these.

Glucose, galactose, mannose, fructose, xylose, or arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, starchiose, maltitol, lactitol, lactulose, cellobiose, Maltose, cellotriose, maltotriose, raffinose or kestoose.

In addition, genthiobiose, genthiotriose, genthiotetraose, xyltriose, galactosyl sucrose and the like can also be mentioned.

Among these compounds, compounds having both a pyranose structure and a furanose structure are particularly preferable.

As examples, sucrose, kestoose, nythose, 1F-fructosyl nythose, starchiose and the like are preferable, more preferably sucrose.

There is no restriction | limiting in particular as monocarboxylic acid used for esterifying all or part of the OH group in the pyranose structure or furanose structure of this invention, A well-known aliphatic monocarboxylic acid and an alicyclic monocarboxylic acid , Aromatic monocarboxylic acid and the like can be used. The carboxylic acid used may be one kind or a mixture of two or more kinds.

Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelagonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecyl acid, Lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachinic acid, behenic acid, lignoseric acid, sertoic acid, heptaconic acid, Saturated fatty acids, such as montanic acid, melisic acid, and lacseric acid, unsaturated fatty acids, such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, octenic acid, etc. are mentioned.

As an example of a preferable alicyclic monocarboxylic acid, acetic acid, cyclopentanecarboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof are mentioned.

Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids, cinnamic acids, benzyl acids, biphenylcarboxylic acids, naphthalene carboxylic acids, and tetracarboxylic acids having an alkyl group and an alkoxy group introduced into a benzene ring of benzoic acid such as benzoic acid and toluic acid. Aromatic monocarboxylic acids or derivatives thereof having two or more benzene rings, such as traline carboxylic acid, and the like, and more specifically, xyllic acid, hemelic acid, mesitylene acid, prentylic acid and γ-isode Lylic acid, duryl acid, mesitoic acid, α-isoduryl acid, cumin acid, α-toluic acid, hydroatroic acid, atroic acid, hydrocinnamic acid, salicylic acid, o-anisic acid, m-anisic acid, p-ani Succinic acid, creosote acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocatechinic acid, β-resoric acid, vanillic acid, isovanlinic acid, beratric acid, o-veratralic acid, gallic acid , Asaronic acid, Mandelic acid, Homoanisic acid, Homovanillinic acid, Homo Although veratric acid, o-homoberatric acid, phthalonic acid, and p-coumaric acid are mentioned, benzoic acid is especially preferable.

The ester compound of an oligosaccharide can be applied as a compound which has 1-12 of at least 1 of a pyranose structure or a furanose structure in this invention.

Oligosaccharides are prepared by applying enzymes such as amylase to starch, sucrose, and the like. The oligosaccharides applicable to the present invention include, for example, maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides and xyl oligosaccharides. have.

In addition, the said ester compound is a compound which condensed 1 or more of 12 or more of the pyranose structure or furanose structure represented by following formula (A). However, R <_11> -R <_15> , R <_21> -R <_25> represents a C2-C22 acyl group or hydrogen atom, m and n represent the integer of 0-12, respectively, and m + n represents the integer of 1-12.

<Formula A>

It is preferable that R <_11> -R <_15> , R <_21> -R <_25> is a benzoyl group and a hydrogen atom. The benzoyl group may further have substituent _R26 (p is 0-5), for example, an alkyl group, an alkenyl group, an alkoxyl group, and a phenyl group may be mentioned, and these 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.

Hereinafter, although the specific example of the ester compound in this invention is given, this invention is not limited to this.

The cellulose ester films (first and second optical compensation layers 3 and 5) of the present invention contain the sugar ester compounds of the present invention in the range of 0.5 to 30 of the cellulose ester film in order to suppress fluctuations in retardation values and stabilize display quality. It is preferable to contain mass%, and it is preferable to contain 5-30 mass% especially.

(3.3.3) (meth) acrylic compounds

As the (meth) acrylic compound to be used in the present invention, it is preferable to exhibit negative birefringence with respect to the stretching direction as a function when it is contained in the optical compensation film, and the structure is not particularly limited. It is preferable that it is a polymer whose obtained weight average molecular weights are 500 or more and 30000 or less.

(Birefringence test method of (meth) acrylic compound)

After melt | dissolving a (meth) acrylic-type polymer (compound) in a solvent and cast-forming, it heat-dried and evaluated birefringence with respect to the film 80% or more of transmittance | permeability.

The refractive index measurement was performed on the Abbe refractometer-4T (made by Atago Co., Ltd.) using the multi-wavelength light source. The refractive index ny in the stretching direction and the refractive index in the orthogonal in-plane direction were set to nx. For films having (ny-nx) <0 for each of the refractive indices of 550 nm, the (meth) acrylic polymer is judged to be negative birefringence with respect to the stretching direction.

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

By controlling the composition of the polymer so that the weight average molecular weight of the polymer is 500 or more and 30000 or less, for example, when the optical compensation film is a particularly preferred cellulose ester film in the present invention, compatibility of the cellulose ester and the polymer is satisfactorily achieved. can do.

With respect to the (meth) acrylic polymer having an aromatic ring in the side chain or the (meth) acrylic polymer having a cyclohexyl group in the side chain, as long as the weight average molecular weight is 500 or more and 10000 or less, not only the above but also the cellulose ester film after film formation It is excellent in transparency, very low moisture permeability, and shows the outstanding performance as a protective film for polarizing plates.

Since the said polymer has a weight average molecular weight of 500 or more and 30000 or less, it is thought that it exists between an oligomer and a low molecular weight polymer. In order to synthesize | combine such a polymer, since it is difficult to control molecular weight with a normal polymer, it is a method which does not increase molecular weight so much, It is preferable to use the method which can arrange 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 not having an aromatic ring and a hydroxyl group in a molecule, an ethylenically unsaturated monomer Xb not having an aromatic ring in a molecule and a hydroxyl group, A polymer having a weight average molecular weight of 2000 or more and 30000 or less obtained by copolymerizing an copolymerizable ethylenically unsaturated monomer except for 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 it is the polymer Y of the obtained weight average molecular weights 500 or more and 3000 or less.

[Polymer X, polymer Y]

As a method of adjusting Ro and Rth of the optical compensation film in this invention, the ethylenically unsaturated monomer Xa which does not have an aromatic ring and a hydroxyl group in a molecule, the ethylenically unsaturated monomer Xb which does not have an aromatic ring in a molecule | numerator, and has a hydroxyl group, High molecular weight polymer X having a weight average molecular weight of 2000 or more and 30000 or less obtained by copolymerizing copolymerizable ethylenically unsaturated monomers except Xa and Xb, more preferably ethylenically unsaturated monomers having no aromatic rings Ya and ethylene copolymerizable with Ya It is preferable to contain low molecular weight polymer Y of 500 or more and 3000 or less of weight average molecular weight obtained by superposing | polymerizing a unsaturated unsaturated monomer.

Polymer X used in the present invention is an ethylenically unsaturated monomer Xa which does not have an aromatic ring and a hydroxyl group in a molecule, an ethylenically unsaturated monomer Xb which does not have an aromatic ring in a molecule and a hydroxyl group, and copolymerizable ethylenic except for Xa and Xb. It is a polymer of the weight average molecular weights 2000 or more and 30000 or less obtained by copolymerizing an unsaturated monomer.

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

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

<Formula X>

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

(In the formula (X), Xa represents an ethylenically unsaturated monomer having no aromatic ring and a hydroxyl group in the molecule, Xb represents an ethylenically unsaturated monomer having no hydroxyl ring in the molecule and having a hydroxyl group, Xc except Xa, Xb) Copolymerizable ethylenically unsaturated monomers, m, n and p each represent a molar composition ratio, provided that m ≠ 0, n ≠ 0, m + n + p = 100)

Moreover, as polymer X, Preferably, it is a polymer represented by following formula (X-1).

<Formula X-1>

-[CH ₂ -C (-R1) (-CO ₂ R2)] m- [CH ₂ -C (-R3) (-CO ₂ R4-OH)-] n- [Xc] p-

(In Formula (X-1), R1 and R3 each represent a hydrogen atom or a methyl group, R2 represents an alkyl or cycloalkyl group having 1 to 12 carbon atoms, and R4 represents -CH _2- , -C ₂ H ₄ -or- C ₃ H _6- , wherein Xc is a monomer polymerizable to [CH ₂ -C (-R1) (-CO ₂ R2)] or [CH ₂ -C (-R3) (-CO ₂ R4-OH)-] Unit, where m, n and p represent molar composition ratios, where m ≠ 0, n ≠ 0, m + n + p = 100)

Although the monomer as a monomer unit which comprises the polymer X used for this invention is listed below, it is not limited to this.

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

The ethylenically unsaturated monomer Xa having no aromatic ring and hydroxyl group in the molecule is, for example, 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 (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i) -), Myristyl acrylic acid (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), or the like, or those obtained by changing the acrylic acid ester to methacrylic acid ester. Among these, it is preferable that they are methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and propyl methacrylate (i-, n-).

As for the ethylenically unsaturated monomer Xb which does not have an aromatic ring in a molecule | numerator, and has a hydroxyl group, acrylic acid or methacrylic acid ester is preferable as a monomer unit which has a hydroxyl group, For example, acrylic acid (2-hydroxyethyl) and acrylic acid (2- Hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl) or those substituted with methacrylic acid, preferably acrylic acid (2-hydroxyethyl) and methacrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl) and acrylic acid (3-hydroxypropyl).

As Xc, although there is no restriction | limiting in particular if it is an ethylenically unsaturated monomer copolymerizable with monomers other than Xa and Xb, but what does not have an aromatic ring is preferable.

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. P of Xc is 0-10. Xc may be a plurality of monomer units.

If the molar composition ratio of Xa is large, compatibility with cellulose ester will become favorable, but the retardation value Rth of a film thickness direction will become large. When the molar composition ratio of Xb is large, the compatibility is deteriorated, but the effect of reducing Rth is high.

In addition, since there exists a tendency for haze to generate | occur | produce at the time of film forming, when the molar composition ratio of Xb exceeds the said range, it is preferable to aim at these optimization and to determine the molar composition ratio of Xa and Xb.

It is more preferable that the weight average molecular weights of the high molecular weight polymer X are 5000 or more and 30000 or less, More preferably, they are 8000 or more and 25000 or less.

By making a weight average molecular weight 5000 or more, since the advantage of few dimensional changes under high temperature, high humidity of an optical compensation film, and few curls as a polarizing plate protective film is obtained, it is preferable.

When the weight average molecular weight is 30000 or less, compatibility with a cellulose ester improves more, the bleed out under high temperature, high humidity, and haze generation immediately after film forming are suppressed.

The weight average molecular weight of polymer X used for this invention can be adjusted with a well-known molecular weight adjustment method. As such a molecular weight adjustment method, the method of adding chain transfer agents, such as carbon tetrachloride, lauryl mercaptan, and octyl thioglycolate, etc. are mentioned, for example.

Moreover, although superposition | polymerization temperature is normally performed at 130 degreeC from room temperature, Preferably it is 50 degreeC-100 degreeC, It is possible to adjust this temperature or polymerization reaction time.

As the measuring method of an average molecular weight, the method mentioned in (3.1.1) can be used.

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

Moreover, setting it as 3000 or less is preferable in order to maintain the retardation value Rth fall performance. Ya is preferably an acrylic or methacryl monomer having no aromatic ring.

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

<Formula Y>

-[Ya] k- [Yb] q-

In the above 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 for this invention, More preferably, it is a polymer represented by following General formula Y-1.

<Formula Y-1>

-[CH ₂ -C (-R5) (-CO ₂ R6)] k- [Yb] q-

In said Formula (Y-1), R <5> represents a hydrogen atom or a methyl group, respectively. R6 represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group. Yb represents a monomeric unit copolymerizable with [CH ₂ -C (-R5) (-CO ₂ R6)]. k and q each represent a molar composition ratio. However, 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 (-R5) (-CO ₂ R6)] which is Ya. Plural number of Yb may be sufficient. k + q = 100, q becomes like this. Preferably it is 1-30.

The ethylenically unsaturated monomer Ya constituting the polymer Y obtained by polymerizing an ethylenically unsaturated monomer having no aromatic ring is, for example, an acrylic 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 (n-, i-), octyl acrylate (n -, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), cyclohexyl acrylate, acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2 -Hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), methacrylic acid ester, the acrylic acid Changing ester to methacrylic acid ester; As unsaturated acid, acrylic acid, methacrylic acid, maleic anhydride, crotonic acid, itaconic acid etc. are mentioned, for example.

Yb is not particularly limited as long as it is an ethylenically unsaturated monomer copolymerizable with Ya. Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl pivalate, vinyl caproate, vinyl caprate, and la. Vinyl urate, vinyl myristic acid, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylic acid, vinyl octylate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl cinnamate, and the like are preferable. Plural number of Yb may be sufficient.

In order to synthesize | combine the polymers X and Y, since control of molecular weight is difficult by normal superposition | polymerization, it is a method which does not increase molecular weight so much, It is preferable to use the method which can arrange molecular weight as much as possible.

As such a polymerization method, 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 normal polymerization, a chain transfer agent such as a mercapto compound or carbon tetrachloride in addition to the polymerization initiator In addition to the polymerization initiator, a method of using a polymerization terminator such as benzoquinone or dinitrobenzene, and also one thiol group and a secondary hydroxyl group in JP-A-2000-128911 or 2000-344823 And a method of bulk polymerization using a polymerization catalyst in which the compound having the above or the compound and the organometallic compound are used together, and all of them are preferably used in the present invention.

In particular, the polymerization method in which the polymer Y uses the compound which has a thiol group and a secondary hydroxyl group in a molecule | numerator as a chain transfer agent is preferable. In this case, the terminal of polymer Y has a hydroxyl group and a thioether resulting from a polymerization catalyst and a chain transfer agent. The compatibility of Y and a cellulose ester can be adjusted with this terminal residue.

It is preferable that the hydroxyl value of polymer X and Y is 30-150 [mgKOH / g].

(Measurement of 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 required to neutralize the acetic acid bound to hydroxyl groups when 1 g of the sample is acetylated.

Specifically, sample Xg (approximately 1 g) is correctly weighed into a flask, and 20 ml of an acetylation reagent (400 ml of pyridine is added to 20 ml of acetic anhydride) is accurately added thereto. An air cooling tube is mounted at the inlet of the flask and heated in a glycerin bath at 95 to 100 ° C. After 1 hour and 30 minutes, the mixture is cooled, 1 ml of purified water is added from the air cooling tube, and acetic anhydride is decomposed into acetic acid.

Subsequently, titration is performed with 0.5 mol / L potassium hydroxide ethanol solution using a potentiometric titration device, and the inflection point of the obtained titration curve is defined as the end point.

In addition, as a blank test, it titrates without a sample and calculates the inflection point of a titration curve. The hydroxyl value is calculated by the following equation.

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

(Wherein B is the amount of 0.5 mol / l potassium hydroxide ethanol solution used in the blank test (ml), C is the amount of 0.5 mol / l potassium hydroxide ethanol solution used in the titration (ml), f is 0.5 mol / l) Titer of potassium hydroxide ethanol solution, D is acid value, and 28.05 is 1/2 of 56 mol of 1 mol amount of potassium hydroxide)

The above-mentioned polymer X and the polymer Y are all excellent in compatibility with a cellulose ester, there is no evaporation or volatilization, it is excellent in productivity, the retention property as a protective film for polarizing plates is good, moisture permeability is small, and it is excellent in dimensional stability.

Content in the optical compensation film of the polymer X and the polymer Y is Xg (mass% = (mass of the mass / cellulose ester of polymer X) * 100), and content of the polymer Y is Yg (mass%) as content of the polymer X. In other words, it is preferable that the range satisfy the following formulas i and ii.

Equation i

5≤Xg + Yg≤35 (mass%)

<Equation ii>

0.05≤Yg / (Xg + Yg) ≤0.4

The range with preferable (Xg + Yg) of Formula (i) is 10-35 mass%. The polymer X and the polymer Y have a sufficient effect for adjustment of the retardation value Rth if it is 5 mass% or more as a total amount with respect to the cellulose ester total mass. Moreover, as a total amount, adhesiveness with polarizer PVA is favorable as it is 35 mass% or less.

Polymer X and polymer Y can be added directly to a dope liquid after being added directly, melt | dissolving as a raw material which comprises the dope liquid mentioned later, or melt | dissolving in the organic solvent which melt | dissolves a cellulose ester previously.

(3.4) UV absorbers

In addition, the first and second optical compensation layers 3 and 5 may contain an ultraviolet absorber. A ultraviolet absorber aims at improving durability by absorbing 400 nm or less ultraviolet rays, Especially, it is preferable that the transmittance | permeability in wavelength 370 nm is 10% or less, More preferably, it is 5% or less, More preferably, 2% It is as follows.

Although the ultraviolet absorber used for this invention is not specifically limited, For example, an oxy benzophenone type compound, a benzotriazole type compound, a salicylic acid ester type compound, a benzophenone type compound, a cyanoacrylate type compound, a triazine type compound, a nickel complex salt A system compound, an inorganic powder, etc. are mentioned.

For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxy phenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (Linear and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxy benzophenone, 2,4-benzyloxy benzophenone, and the like, and also tinubin 109, tinubin 171, tinubin 234, Tinuvin, such as Tinuvin 326, Tinuvin 327, and Tinuvin 328, are all commercially available products of Shiva Japan Co., Ltd., and can be used preferably.

The ultraviolet absorber used preferably in this invention is a benzotriazole type ultraviolet absorber, a benzophenone type ultraviolet absorber, and a triazine type ultraviolet absorber, Especially preferably, it is a benzotriazole type ultraviolet absorber and a benzophenone type ultraviolet absorber.

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

<Formula d>

(In formula, R <_1> , R <_2> , R <_3> , R <_4> and R <_5> may be same or different, and 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 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 closed to form a 5 to 6 membered carbocyclic ring. Good)

In addition, these groups described above may have any substituent.

Although the specific example of the benzotriazole type ultraviolet absorber used for this invention is given to the following, this invention is not limited to these.

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'-methylphenyl) benzotriazole

UV-6: 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol)

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

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

UV-9: octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3 A mixture of -tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (tinuvin 109)

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, these alkyl groups, alkenyl groups and phenyl groups may have a substituent, A represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group, A cycloalkyl group, an alkylcarbonyl group, an alkylsulfonyl group or a -CO (NH) n-1-D group, D represents an alkyl group, an alkenyl group or a phenyl group which may have a substituent, and m and n represent 1 or 2)

In the above, the alkyl group is, for example, a straight-chain or branched aliphatic group having up to 24 carbon atoms, the alkoxyl group is, for example, an alkoxyl group having up to 18 carbon atoms, and the alkenyl group is, for example, allyl at an alkenyl group having up to 16 carbon atoms. Group, 2-butenyl group, etc. are shown. Examples of the substituent for the alkyl group, the alkenyl group, and the phenyl group include a halogen atom, for example, a chlorine atom, a bromine atom, a fluorine atom, a hydroxyl group, and a phenyl group (the phenyl group may substitute an alkyl group or a halogen atom). Can be.

Although the specific example of the benzophenone type ultraviolet absorber represented by general formula (e) below is shown, this invention is not limited to these.

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, disk-shaped compounds, such as a compound which has a 1,3,5 triazine ring, are also used suitably as a ultraviolet absorber.

It is preferable that the 1st, 2nd optical compensation layers 3 and 5 in this invention contain 2 or more types of ultraviolet absorbers.

Further, as the ultraviolet absorber, a polymer ultraviolet absorber can also be preferably used, and in particular, an ultraviolet absorber of the polymer type described in JP-A-6-148430 is preferably used.

The UV absorber may be added to an dope after dissolving the UV absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, or directly in the dope composition. You may add. What does not dissolve in an organic solvent like an inorganic powder is added to dope after disperse | distributing in an organic solvent and a cellulose ester using a dissolver and a sand mill.

The amount of the ultraviolet absorber used is not uniform depending on the type of UV absorber, the conditions of use, and the like. However, when the dry film thickness of the optical compensation films (optical compensation layers 3 and 5) is 30 to 200 m, the optical compensation film is 0.5 to 0.5 m. 10 mass% is preferable, and 0.6-4 mass% is more preferable.

(3.5) antioxidant

Antioxidants are also known as antioxidants. When a liquid crystal image display device etc. are put in the state of high humidity high temperature, deterioration of the 1st, 2nd optical compensation layers 3 and 5 as an optical compensation film may occur. Since antioxidant has a role which slows down or prevents an optical compensation film from decomposing | disassembling, for example by halogen of the amount of residual solvent in a optical compensation film, phosphoric acid of a phosphate additive, etc., it is preferable to contain it in the said optical compensation film. .

As such an antioxidant, a hindered phenol compound is preferably used. For example, 2,6-di-t-butyl-p-cresol and pentaerythryl-tetrakis [3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexane Diol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3 , 5-di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethylene bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylene bis (3,5-di-t-butyl- 4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5 -Di-t-butyl-4-hydroxybenzyl) -isocyanurate, etc. are mentioned. Especially 2,6-di-t-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol -Bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di You may use together phosphorus process stabilizers, such as -t- butylphenyl) phosphite.

The amount of these compounds added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm, based on the mass ratio of the cellulose derivative.

(3.6) particulates

It is preferable that the 1st, 2nd optical compensation layers 3 and 5 in this invention contain microparticles | fine-particles.

As fine particles used in the present invention, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate and silicic acid Magnesium and calcium phosphate. It is preferable that microparticles | fine-particles contain silicon from a low turbidity, and especially silicon dioxide is preferable.

5-400 nm is preferable and, as for the average particle diameter of the primary particle of microparticles | fine-particles, 10-300 nm is more preferable. These may be contained mainly as a secondary aggregate with a particle diameter of 0.05-0.3 micrometer, and it is also preferable that it is contained as a primary particle, without being aggregated, if it is a particle | grains of an average particle diameter of 100-400 nm. It is preferable that content of these microparticles | fine-particles in the optical compensation films 3 and 5 is 0.01-1 mass%, and 0.05-0.5 mass% is especially preferable. In the case of the optical compensation films 3 and 5 of the multilayer structure by a covalent smoke method, it is preferable to contain this addition amount microparticles on the surface.

The fine particle of silicon dioxide is marketed under the brand name of aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd. product), for example. , Can be used.

The fine particles of zirconium oxide are commercially available under the trade names of Aerosil R976 and R811 (above Nippon Aerosil Co., Ltd.), for example, and can be used.

Examples of the polymer include silicone resins, fluororesins and acrylic resins. Silicone resin is preferable, and it is preferable to have a three-dimensional network structure especially, for example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (above Toshiba Silicone Co., Ltd. make). It is marketed under the brand name, and can be used.

Among these, aerosil 200V and aerosil R972V are particularly preferably used because the effect of lowering the coefficient of friction is great while keeping the haze of the optical compensation film low. In the optical compensation films 3 and 5 used by this invention, it is preferable that the dynamic friction coefficient of at least one surface is 0.2-1.0.

Various additives may be added to dope which is a cellulose ester containing solution before film forming, and an additive solution may be prepared separately, and may be added inline. Particularly, in order to reduce the load on the filter medium, it is preferable to add a part or the whole amount inline.

When adding an additive solution inline, it is preferable to melt | dissolve a small amount of cellulose esters in order to improve the mixing property with dope. The amount of preferable cellulose ester is 1-10 mass parts with respect to 100 mass parts of solvents, More preferably, it is 3-5 mass parts.

In the present invention, in order to perform inline addition and mixing, for example, an inline mixer such as a static mixer (manufactured by Toray Engineering Co., Ltd.) or SWJ (Toray Stationary Tube Mixer High Mixer) is preferably used.

(3.7) Manufacturing Method of Optical Compensation Film

Next, the manufacturing method of the optical compensation film as the 1st, 2nd optical compensation layers 3 and 5 in this invention is demonstrated.

Even if the optical compensation film is a film manufactured by the solution casting method or a film manufactured by the melt casting method, it can be used preferably.

The manufacture of the optical compensation film of this invention is a process of manufacturing a dope by dissolving a cellulose ester and an additive in a solvent, the process of casting on the endless metal support which dope infinitely, the process of drying a flexible dope as a web, a metal support It performs by the process of peeling from a process, the process of extending | stretching or holding a width, the process of drying, and the process of winding up the finished film.

The process of manufacturing dope is demonstrated. The concentration of the cellulose ester in the dope is preferable because the higher the concentration of the cellulose ester can be reduced after being flexible to the metal support. However, if the concentration of the cellulose ester is too high, the load during filtration increases and the filtration accuracy deteriorates. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%.

Although the solvent used by dope may be used independently and may use 2 or more types together, it is preferable to mix and use the good solvent and poor solvent of a cellulose ester from a viewpoint of production efficiency, and it is solubility of a cellulose ester that there are many good solvents. It is preferable at the point of. The preferable ranges of the mixture ratio of a good solvent and a poor solvent are 70-98 mass% of good solvents, and are 2-30 mass% of poor solvents. A good solvent and a poor solvent are defined as a poor solvent which melt | dissolves the cellulose ester to be used independently and swells alone or does not melt | dissolve alone. Therefore, a good solvent and a poor solvent change according to the average degree of aceletization (acetyl group substitution degree) of a cellulose ester, For example, when using acetone as a solvent, the acetic acid ester of a cellulose ester (acetyl group substitution degree 2.4), cellulose acetate In propionate, it becomes a good solvent, and in acetic acid ester of cellulose (acetyl group substitution degree 2.8), it becomes a poor solvent.

Although the good solvent used for this invention is not specifically limited, Organic halogen compounds, such as methylene chloride, dioxolane, acetone, methyl acetate, methyl acetoacetate, etc. are mentioned. Especially preferably, methylene chloride or methyl acetate is mentioned.

In addition, the poor solvent used for this invention is although it does not specifically limit, For example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are used preferably. Moreover, it is preferable that 0.01-2 mass% of water is contained in dope. In addition, the solvent used for melt | dissolution of a cellulose ester collect | recovers the solvent removed from the film by drying in a film forming process, and reuses and uses it. Although a small amount of additives added to the cellulose ester, such as a plasticizer, an ultraviolet absorber, a polymer, and a monomer component, may be contained in the recovery solvent, even if these are included, they can be preferably reused. It may be.

As a dissolution method of the cellulose ester at the time of manufacturing the above-mentioned dope, a general method can be used. When heating and pressurization are combined, it can heat above the boiling point in normal pressure. It is preferable to melt and dissolve while heating at a temperature in a range not higher than the boiling point of the solvent at a normal pressure and the solvent does not boil under pressure, because it prevents the generation of bulky debris called gels or lumps. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding and dissolving a good solvent further is also used preferably.

Pressurization may be performed by a method of press-fitting an inert gas such as nitrogen gas, or by increasing the vapor pressure of the solvent by heating. It is preferable to perform heating from the outside, for example, a jacket type is preferable because temperature control is easy.

Although it is preferable from the viewpoint of the solubility of a cellulose ester that heating temperature which the solvent was added to is high, when heating temperature is too high, required pressure will become large and productivity will worsen. Preferable heating temperature is 45 degreeC-120 degreeC, 60 degreeC-110 degreeC is more preferable, and 70 degreeC-105 degreeC is still more preferable. In addition, the pressure is adjusted so that the solvent does not boil at the set temperature.

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

Subsequently, this cellulose-ester solution is filtered using suitable filter media, such as a filter paper. As a filter medium, although absolute filtration precision is small in order to remove an insoluble matter etc., it is preferable, but when there is too little absolute filtration precision, there exists a problem that clogging of a filter medium is easy to produce. Therefore, the filter medium of 0.008 mm or less of absolute filtration accuracy is preferable, A 0.001-0.008 mm filter medium is more preferable, A 0.003-0.006 mm filter medium is still more preferable.

There is no restriction | limiting in particular in the material of a filter medium, Although a normal filter medium can be used, since the filter medium made from plastics, such as polypropylene and Teflon (trademark), and the filter medium made from metals, such as stainless steel, do not lose a fiber etc., it is preferable. . It is preferable to remove and reduce the impurity contained in the cellulose ester which is a raw material, especially a bright point foreign substance by filtration.

A bright point foreign substance is a point where two polarizing plates are arrange | positioned in the cross nicol state, the optical film etc. were placed between them, the light from the opposite side leaks when the light is irradiated from one polarizing plate side, and observed from the other polarizing plate side. It refers to (foreign substance), and it is preferable that the number of bright points having a diameter of 0.01 mm or more is 200 pieces / cm ² or less. More preferably, it is 100 pieces / cm <^2> or less, More preferably, it is 50 pieces / m <^2> or less, Especially preferably, it is 0-10 pieces / cm <^2> or less. Moreover, it is preferable that the bright point of 0.01 mm or less is also small.

The dope can be filtered by a conventional method, but the method of filtration while heating at a temperature in the range not lower than the boiling point at the normal pressure of the solvent and not boiling the solvent under pressure is the difference between the filtration pressure before and after filtration (called differential pressure). It is preferable because the rise of) is small. Preferable temperature is 45-120 degreeC, 45-70 degreeC is more preferable, and it is still more preferable that it is 45-55 degreeC.

It is preferable that the filtration pressure is small. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and even more preferably 1.0 MPa or less.

Here, the softness of the dope will be described.

It is preferable that the surface of the metal support body in the casting (cast) process is mirror-finished, and the metal support body is the drum which plate-finished the surface with the stainless steel belt or casting. The width of the cast can be 1 to 4 m. The surface temperature of the metal support of the casting step is preferably higher at a temperature below −50 ° C. to the boiling point of the solvent because it can speed up the drying speed of the web. . Preferable support body temperature is 0-40 degreeC, and 5-30 degreeC is more preferable. Or it is also a preferable method to gelatinize a web by cooling and peeling from a drum in the state containing many residual solvents. The method of controlling the temperature of the metal support is not particularly limited, but there is a method of blowing hot or cold air or a method of bringing hot water into contact with the back surface of the metal support. Use of warm water is preferable in that the time until the temperature of the metal support becomes constant is preferable because heat transfer is efficiently performed. When using warm air, the wind of temperature higher than desired temperature may be used.

In order that an optical compensation film may show favorable planarity, the amount of residual solvent at the time of peeling a web from a metal support body is preferably 10 to 150 mass%, more preferably 20 to 40 mass% or 60 to 130 mass%, Especially preferably, it is 20-30 mass% or 70-120 mass%.

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

Residual solvent amount (mass%) = {(M-N) / N} × 100

In addition, M is the mass of the sample extract | collected at the arbitrary time during manufacture or after a web or film, and N is the mass after heating M at 115 degreeC for 1 hour.

Moreover, in the drying process of an optical compensation film, it is preferable to peel a web from a metal support body and to dry it, and to make residual solvent quantity 1 mass% or less, More preferably, it is 0.1 mass% or less, Especially preferably, It is 0-0.01 mass% or less.

In the film drying process, generally, the method of drying, conveying a web by a roll drying method (the method of passing-drying a web to many rolls arrange | positioned up and down) and a tenter system, is used.

At this time, when manufacturing the optical compensation film as the 1st optical compensation layer 3, it is preferable to laminate | shrink a shrinkable film by bonding a shrinkable film to the cellulose resin film to dry.

Moreover, when manufacturing the optical compensation film as the 2nd optical compensation layer 5, it is preferable to perform a biaxial stretching process.

In order to produce the optical compensation film of this invention, it is especially preferable to extend | stretch in the width direction (horizontal direction) by the tenter system which grips both ends of a web with a clip etc. It is preferable that peeling tension peels at 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 particular limitation, but is preferably performed by hot air from the viewpoint of simplicity.

The drying temperature in the drying step of the web is preferably increased stepwise at 40 to 200 ° C.

Although the film thickness of an optical compensation film is not specifically limited, 10-200 micrometers is used. It is especially preferable that the film thickness is 10-100 micrometers. More preferably, it is 20-60 micrometers.

As the optical compensation film of the present invention, one having a width of 1 to 4 m is used. In particular, a width of 1.4 to 4 m is preferably used, particularly preferably 1.6 to 3 m. When it exceeds 4m, conveyance will become difficult.

According to the liquid crystal display device 1 described above, the liquid crystal molecules in the liquid crystal cell 4 are aligned in the thickness direction of the liquid crystal cell 4 at the time of black display, and the first and second optical compensation layers 3 and 5 are Since nx1> nz1> ny1, nx2≥ny2> nz2, and DSP (Ro1) <1 <DSP (Rth2) are satisfied, it is possible to enlarge the viewing angle, improve the front contrast, and prevent color shift when viewed from the inclined direction. (See examples).

In addition, in the said 1st Embodiment, although the liquid crystal display device which concerns on this invention was demonstrated as the liquid crystal display device 1 shown to FIG. 1 (a), the liquid crystal display device shown to FIG. 1 (b) ( 1A) may be used. Here, in the liquid crystal display device 1A of Fig. 1B, the first polarizer 2, the first optical compensation layer 3, the liquid crystal cell 4, The second optical compensation layer 5 and the second polarizer 6 are stacked in this order, the absorption axis 2J of the first polarizer 2 and the slow axis of the first optical compensation layer 3 ( 3J is parallel, 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 is orthogonal to each other. ) And the absorption axis 6J of the second polarizer 6 are arranged to be orthogonal to each other. In FIG. 1B, the backlight is shown as a lower side in the drawing, but may be an upper side.

Second Embodiment

Next, 2nd Embodiment of this invention is described. In addition, the same code | symbol is attached | subjected to the component same as the said 1st Embodiment, and the description is abbreviate | omitted.

FIG. 2A 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 device 1D has a first polarizer 2, a first optical compensation layer 3D, a liquid crystal cell 4, and a second optical from the viewing side toward the backlight side. The compensation layer 5 and the second polarizer 6 are stacked in this order. In addition, 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 toward the backlight side.

More specifically, the first polarizer 2, the second polarizer 6, and the biaxial film 30 have an absorption axis 2J of the first polarizer 2 and a slow axis 30J of the biaxial film 30. ) Is perpendicular to each other, 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 30J and the second polarizer of the biaxial film 30 are orthogonal to each other. The absorption shaft 6J of (6) is arrange | positioned so that it may become parallel. In addition, although the backlight is shown as the lower side in the figure in FIG. 2, you may make it the upper side.

(First optical compensation layer)

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

The first optical compensation layer 3D is preferably a film although the shape thereof is not limited. 40-100 micrometers is preferable and, as for the thickness d of a film, 40-70 micrometers is more preferable.

<Biaxial film>

The biaxial film 30 is a film whose refractive index satisfies nx> ny> nz. As this biaxial film 30, the thing which extended | stretched the cellulose resin film similar to the 1st optical compensation layer 3 in the said 1st Embodiment can be used.

<Middle floor>

In the optical compensation layer 3D of the present invention, an intermediate layer (alignment film, not shown) that assists 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 a polyether chain as a main chain, and more preferably a binder polymer having a saturated hydrocarbon chain as the main chain.

Especially preferably, it is a resin composition which hardens | cures via crosslinking reaction etc. by irradiation of active rays, such as an ultraviolet-ray or an electron beam, or a mixed composition of resin which has a crosslinking agent and a reaction site | part.

As curable resin, ultraviolet curable acrylate, 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, for example. System resin is used preferably.

UV-curable urethane acrylate resins are generally 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter, acrylate is methacrylate) obtained by reacting an isocyanate monomer or a prepolymer with a polyester polyol. Since only a acrylate is shown because it contains a rate), it can be obtained easily by making the acrylate-type monomer which has a hydroxyl group, such as 2-hydroxypropyl acrylate, react further.

For example, the thing of Unexamined-Japanese-Patent No. 59-151110 can be used. For example, 100 parts of Shiko UV-7510B (made by Nippon Kose Kagaku Co., Ltd.), Unidyk 17-806 (made by Dainippon Ink, Inc.), and 1 part of colonate L (made by Nippon Polyurethane Co., Ltd.) Mixtures and the like are preferably used.

As ultraviolet curing polyester acrylate type resin, what is generally formed is easily formed by making 2-hydroxyethyl acrylate and 2-hydroxy acrylate-type monomer react with polyester polyol, Unexamined Japanese patent ) 59-151112 can be used.

Specific examples of the ultraviolet curable epoxy acrylate resin include epoxy acrylate as an oligomer, and a reactive diluent and a photopolymerization initiator are added thereto to react with each other, and are produced by Japanese Unexamined Patent Application Publication No. Hei 1-105738. Can be used.

Specific examples of ultraviolet curing polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and alkyl modifications. 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, α-amyl oxime ester, thioxanthone and the like and derivatives thereof. You can also use it with a photosensitizer.

In addition, when using an epoxy acrylate type photoinitiator, sensitizers, such as n-butylamine, triethylamine, and tri-n-butylphosphine, can be used.

The photoinitiator or photosensitizer used for curable resin composition is 0.1-25 mass parts with respect to 100 mass parts of said compositions, Preferably it is 1-15 mass parts.

As the acrylate resin, methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane di Acrylate, 1, 4- cyclohexyl dimethyl diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylic ester, and the like.

As these commercial items, Adeka Optomer KR-BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (made by Asahi Denka Co., Ltd.); Koei hard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS-101, FT -102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Koei Chemical Industries, Ltd.); Seika beam PHC2210 (S), PHCX-9 (K-3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (Dainichi Seika High School Co., Ltd.); KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UCB Co., Ltd.); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120, RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 Ink Kagaku Kogyo Co., Ltd.); Orex No. 340 Kryya (manufactured by Chugoku Paints Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Kasei Kogyo Co., Ltd.); SP-1509 and SP-1507 (manufactured by Showa Kobunshi Co., Ltd.); RCC-15C (product made in Grace Japan), aronix M-6100, M-8030, M-8060 (product made by Toagosei Co., Ltd.), NK hardware B-420, NK ester A-DOG, NK ester A- IBD-2E (made by Shin-Nakamura Kagaku Kogyo Co., Ltd.) etc. can be selected suitably, and can be used.

In addition, as others, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dioxane glycol acrylate, ethoxylated acryl Elate, alkyl modified dipentaerythritol pentaacrylate, etc. are mentioned.

As a mixed composition of resin which has a crosslinking agent of this invention, and a reaction site | part, polyvinyl alcohol, glyoxal, gelatin, glyoxal, etc. are mentioned, for example.

In addition, the intermediate layer may contain a fluorine-acrylic copolymer resin. Fluoro-acryl copolymer resin is copolymer resin which consists of a fluorine monomer and an acryl monomer, and especially the block copolymer which consists of a fluorine monomer segment and an acryl monomer segment is preferable.

(Method for Manufacturing Intermediate Layer)

The intermediate layer is coated with a coating composition for forming the intermediate layer on the biaxial film 30 by using a known method such as a gravure coater, dip coater, reverse coater, wire bar coater, die coater, inkjet method, and then dried by heating, UV curing is preferred.

The coating amount is suitably 0.1 to 40 µm as the wet film thickness, and preferably 0.5 to 30 µm.

Moreover, as dry film thickness, average film thickness is 0.01-1 micrometer, Preferably it is 0.02-0.7 micrometer.

As a light source of the said UV hardening process, as long as it is a light source which generate | occur | produces an ultraviolet-ray, it can use 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, or the like can be used.

Although irradiation conditions differ with each lamp | ramp, the irradiation amount of an active line is 5-500mJ / cm <^2> normally, Preferably it is 5-150mJ / cm <^2> .

Moreover, when irradiating an active line, it is preferable to carry out, applying a tension to the conveyance direction of the biaxial film 30, More preferably, it is performed, giving a tension also in the width direction. As for the tension | tensile_strength to provide, 30-300 N / m is preferable.

The method of providing a tension is not specifically limited, A tension may be provided in a conveyance direction on a back roll, and a tension may be provided in a width direction or a biaxial direction in a tenter. Thereby, the film which is further excellent in planarity can be obtained.

The coating composition which forms an intermediate | middle layer may contain the solvent. As an organic solvent contained in a coating composition, For example, hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), The esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents can also be appropriately selected or a mixture thereof can be used.

As the organic solvent, propylene glycol monoalkyl ether (1 to 4 carbon atoms in the alkyl group) or propylene glycol monoalkyl ether acetic acid ester (1 to 4 carbon atoms in the alkyl group) is preferable. Moreover, as content of an organic solvent, 5-80 mass% is preferable in a coating composition.

<Liquid crystal layer>

The refractive index of the liquid crystal layer 31 satisfies nz> nx = ny, and is what is called a positive C plate. It is preferable that this liquid crystal layer 31 has the following characteristics.

0≤Ro≤10

-500≤Rth≤-100

The liquid crystal layer 31 is coated with a liquid crystal material or a solution of liquid crystal directly on the biaxial film 30 or on the intermediate layer, and subjected to drying and heat treatment (also referred to as alignment treatment) to align the liquid crystal by UV curing or thermal polymerization. It is formed by immobilization and has a phase difference by the rod-like liquid crystal oriented in the vertical direction.

Orienting in a vertical direction here means that rod-shaped liquid crystal exists in the range of 70-90 degree (vertical direction makes 90 degree) with respect to the film surface of the biaxial film 30 as a support body.

The rod-shaped liquid crystal may be inclined with respect to the biaxial film 30, or may be aligned by gradually changing the orientation angle. Preferably it is the range of 80-90 degrees.

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

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

In the case where the liquid crystal material itself is aligned in the vertical direction from the air interface, since the alignment regulating force extends to the interface opposite to the air interface, the alignment film is not particularly necessary, and is also preferable from the viewpoint of simplifying the configuration.

As a specific method of orienting a liquid crystal material perpendicularly | vertically, as described in Unexamined-Japanese-Patent No. 2005-148473 etc., the method of using the orientation film which consists of a crosslinked body of the block polymer composition containing a (meth) acrylic-type block polymer, etc. As described in 2005-265889, a known method such as a method of using a vertical alignment film or a method of using an air interface vertical alignment agent can be used.

In order to make the liquid crystal layer 31 into the ranges of the characteristics of Ro and Rth, the alignment of the rod-shaped liquid crystal layer, the film thickness control, the temperature at the time of ultraviolet curing, the tilt angle control and the support (biaxial film 30) and air It is preferable to control the pretilt angle at the interface.

The liquid crystal layer 31 is formed by curing a liquid crystal material capable of becoming a liquid crystal phase at a predetermined temperature with a predetermined liquid crystal regularity. The upper limit of the temperature which shows a liquid crystal phase will not be specifically limited if it is a temperature which a cellulose-ester film of a base material does not receive damage, for example.

Specifically, from the viewpoint of ease of control of the process temperature and maintenance of dimensional accuracy, 120 ° C. or less is preferable, and more preferably a liquid crystal material that becomes a liquid crystal phase at a temperature of 100 ° C. or less is appropriately used. In addition, the minimum of the temperature which shows a liquid crystal phase can be said that it is the temperature at which a liquid crystal material can maintain an orientation state, when using as a polarizing plate.

As a liquid crystal material used for the liquid crystal layer 31, it is preferable to use a polymeric liquid crystal material. The polymerizable liquid crystal material can be polymerized by irradiating predetermined actinic 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 or a polymerizable liquid crystal polymer may be used, or may be mixed with each other.

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

As a specific polymeric liquid crystal monomer, the rod-like liquid crystalline compound (I) represented by following formula (1) and the rod-like liquid crystalline compound (II) represented by following formula (2) are mentioned. As compound (I), you may mix and use 2 or more types of compounds contained in General formula (1), and like compound (II), you may mix and use 2 or more types of compounds contained in General formula (2). Moreover, 1 or more types of compound (I) and 1 or more types of compound (II) can also be mixed and used.

In General formula (1) which shows a compound (I), although R <^1> and R <^2> respectively represent hydrogen or a methyl group, it is preferable that both R <^1> and R <^2> are hydrogen from the range of the temperature range which shows a liquid crystal phase.

X may be any of 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 a chlorine or methyl group.

In addition, a and b which represent the chain length of the (meth) acryloyloxy group of the both ends of the molecular chain of a compound (I), and the alkylene group which is a spacer of an aromatic ring can respectively take arbitrary integers in the range of 2-12 individually. However, it is preferable that it is the range of 4-10, and it is more preferable that it is the range of 6-9.

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

For example, as a polymerizable rod-like liquid crystalline compound, the literature [Makromol. Chem., 190, 2255 (1989), Advanced Materials 5, 107 (1993)], U.S. Patent No. 4683327, U.S.5622648, U.S. 5770107, International Publication WO95 / 22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, Japanese Patent Laid-Open No. 1-272551, No. 6-16616, No. 7 -110469, 11-80081, Japanese Patent Laid-Open No. 2001-328973, Japanese Patent Laid-Open No. 2004-240188, Japanese Patent Laid-Open No. 2005-99236, Japanese Patent Laid-Open No. 2005-99237 The compound described in Unexamined-Japanese-Patent No. 2005-121827, Unexamined-Japanese-Patent No. 2002-30042, etc. can be used.

In this invention, a photoinitiator is used as needed other than a polymeric liquid crystal material. Although the photoinitiator may be unnecessary when superposing | polymerizing a polymeric liquid crystal material by electron beam irradiation, in the case of hardening by UV radiation (UV) irradiation which is generally used, a photoinitiator is normally used for promotion of superposition | polymerization.

As a photoinitiator, benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, benzoyl benzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzyl methyl ketal , Dimethylaminomethylbenzoate, 2-n-butoxy ethyl-4-dimethylamino benzoate, p-dimethylamino benzoic acid isoamyl, 3,3'-dimethyl-4-methoxybenzophenone, methylobenzoylformate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1 -One, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane- 1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-di Isopropyl Thioxanthone, 2,4-Dimethyl Thioxanthone, Isopropyl Thioxane Or the like can be mentioned 1-chloro-4-propoxy City Oak Santon.

As addition amount of a photoinitiator, generally 0.01%-20% are preferable, More preferably, it is 0.1%-10%, More preferably, it can add to the polymeric liquid crystal material of this invention in the range of 0.5%-5%. have.

Moreover, it is also possible to add a sensitizer in addition to the photoinitiator in the range which does not impair the objective of this invention.

It is preferable that it is in the range of 0.1 micrometer-10 micrometers, and, as for the film thickness of the liquid crystal layer 31 in this invention, it is more preferable to exist in the range which is 0.2-5 micrometers.

A polymeric liquid crystal material mix | blends a photoinitiator, a sensitizer, etc. as needed, manufactures and uses a composition for liquid crystal layer formation, coats it on a base material (biaxial film 30), and forms the layer for liquid crystal layer formation.

As a method of forming the layer which fixed the orientation of a liquid crystal, the method of laminating | stacking on a base material what was previously formed by forming a dry film etc. and making this the layer which fixed the orientation of a liquid crystal, and melt | dissolving or melting a liquid crystal composition, and apply | coat it on a base material Although a method etc. can also be taken, in this invention, a solvent is added as a liquid crystal composition, it coats on a base material using the coating composition which melt | dissolved other components, and removes a solvent to form the layer which fixed the orientation of a liquid crystal. It is preferable. This is a simple process in comparison with other methods.

The solvent is not particularly limited as long as it is a solvent capable of dissolving the above-described polymerizable liquid crystal material and the like and which does not lower the properties of the transparent resin film. Specifically, benzene, toluene, xylene, n-butyl benzene, Hydrocarbons such as diethyl benzene 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 γ-butyrolactone; Amide solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide or dimethylacetamide; Halogen solvents such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, 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; One or two or more kinds of phenols such as phenol and parachlorophenol can be used.

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

Among the above solvents, preferred solvents are hydrocarbon solvents and glycol monoether acetate solvents, and mixed solvents are ethers or ketones and glycols.

Since the concentration of the solution depends on the solubility of the polymerizable liquid crystal material and the like and the film thickness of the liquid crystal layer to be produced, it cannot be uniformly defined, but usually 1% to 60% is preferable, and more preferably 3% to 40%. It is adjusted in the range of%.

The compound of that excepting the above can be added to the composition for liquid crystal layer formation used for this invention within the range which does not impair the objective of this invention.

As a compound which can be added, For example, Polyester (meth) acrylate obtained by making (meth) acrylic acid react with the polyester prepolymer obtained by condensing polyhydric alcohol, monobasic acid, or polybasic acid; Polyurethane (meth) acrylates obtained by reacting a compound having a polyol group and two isocyanate groups with each other and then reacting (meth) acrylic acid with the reaction product; Bisphenol A epoxy resin, bisphenol F epoxy resin, novolak-type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or alicyclic epoxy resin, amine epoxy resin, triphenol methane type Photopolymerizable compounds, such as epoxy (meth) acrylate obtained by making epoxy resin, such as an epoxy resin and a dihydroxy benzene type epoxy resin, and (meth) acrylic acid react, or a photopolymerizable liquid crystalline compound which has an acryl group or a methacryl group, Japan Onium salt, fluorinated acrylate polymer, etc. which are described in Unexamined-Japanese-Patent No. 2007-45993 are mentioned.

The addition amount of these compounds with respect to the composition for liquid crystal layer formation of this invention is chosen in the range which does not impair the objective of this invention, Generally it is preferable that it is 40% or less of the composition for liquid crystal layer formation of this invention, More preferably, Is 20% or less.

By addition of these compounds, the hardenability of the liquid crystal material in this invention improves, the mechanical strength of the obtained liquid crystal layer increases, and its stability improves.

Moreover, surfactant etc. can be added to the composition for liquid crystal layer formation which mix | blended the solvent in order to make coating easy.

Examples of the surfactant that 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 lauryl sulfate, lauryl ammonium sulfate, lauryl sulfate 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 acetate betaine; Nonionic surfactants such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamines; Perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethylammonium salt, perfluoroalkyl group, hydrophilic group containing oligomer, perfluoroalkyl lipophilic group oligomer purple Fluorine-type surfactants, such as a fluoroalkyl group containing urethane, etc. are mentioned.

The amount of the surfactant added varies depending on the kind of the surfactant, the kind of the liquid crystal material, the kind of the solvent, and also the kind of the alignment film for coating the solution, but usually 10 ppm to 10% of the polymerizable liquid crystal material contained in the solution is preferable. More preferably, it is 100 ppm-5%, More preferably, it is 0.1 to 1% of range.

As a method for coating the composition for forming a liquid crystal layer, a spin coating method, a roll coating method, a printing method, an immersion pulling method, a die coating method, a casting method, a bar coating method, a blade coating method, a spray coating method, a gravure coating method, and a reverse A coating method or an extrusion coating method.

As a method of removing a solvent after coating the composition for liquid crystal layer formation, it is performed by air drying, a heating removal, or a pressure reduction removal, the method of combining these, etc., for example. By removing a solvent, the layer which fixed the orientation of a liquid crystal is formed.

In the step of curing the polymerizable liquid crystal material, energy for curing the polymerizable liquid crystal material is provided, and may be thermal energy, but is usually performed by irradiation with ionizing radiation having the ability to cause polymerization.

If necessary, a 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 usually used in view of ease of use of the apparatus, and light having a wavelength of 150 to 500 nm is preferable. More preferably, it is 250-450 nm, More preferably, it is the ultraviolet-ray of the wavelength of 300-400 nm.

In this invention, the method of irradiating an ultraviolet-ray (UV) as active radiation and generating radical from a polymerization initiator in an ultraviolet-ray and performing radical polymerization is preferable. Since the method of using UV as active radiation is an already established technique, it is easy to apply to the present invention including the polymerization initiator to be used.

As a light source for irradiating this ultraviolet light, a low pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), a high pressure discharge lamp (high pressure mercury lamp, a metal halide lamp), or a short arc discharge lamp (ultra high pressure mercury lamp, xenon lamp, Mercury xenon lamps).

Among them, metal halide lamps, xenon lamps, and high pressure mercury lamps are recommended. What is necessary is just to adjust irradiation intensity suitably according to the composition of the polymeric liquid crystal material used for formation of the layer which fixed the orientation of a liquid crystal, and the some degree of a photoinitiator.

Orientation fixation process by irradiation of active radiation may be performed at the process temperature in the process of forming the liquid crystal layer formation layer mentioned above, ie, the temperature conditions which a polymeric liquid crystal material becomes a liquid crystal phase, and at a temperature lower than the temperature which becomes a liquid crystal phase. You may do it.

According to the liquid crystal display device 1D described above, the same effects as those of the first embodiment can be obtained, and the first optical compensation layer 3D forms the biaxial film 30 and the liquid crystal layer 31 of the positive C plate. Since it is a laminated structure which has, the magnitude | size of the phase difference which should be given to an optical compensation layer can be remarkably reduced compared with the case where a 1st optical compensation layer is comprised from a single | mono 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 phase difference of retardation value Ro 대하여 275 to the optical compensation layer in order to achieve the viewing angle enlargement effect. In the compensation layer 3D, when the retardation value Ro = 50-100 is applied to the entire optical compensation layer 3D, a phase difference of 1/2 or less can be achieved to increase the viewing angle. Therefore, unlike the case where the first optical compensation layer is composed of a single layer, the optical compensation layer can be prevented from amplifying the influence of slight optical axis deviation in the plane, thereby reducing the phase difference unevenness and maintaining the front contrast in a high state. (See examples).

In addition, in the said 2nd Embodiment, although the liquid crystal display device which concerns on this invention was demonstrated as liquid crystal display device 1D shown in FIG.2 (a), the liquid crystal display device shown in FIG.2 (b) ( 1E) may be used. Here, in the liquid crystal display device 1E of FIG. 2B, the first polarizer 2, the liquid crystal layer 31 of the first optical compensation layer 3D, and the biaxiality are from the viewing side toward the backlight side. The film 30, the liquid crystal cell 4, the second optical compensation layer 5, and the second polarizer 6 are laminated in this order, and the absorption axis 2J of the first polarizer 2 and The slow axis 30J of the biaxial film 30 is parallel, 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 biaxial film ( The slow axis 30J of 30 and the absorption axis 6J of the 2nd polarizer 6 are arrange | positioned so that it may cross. In FIG. 2B, the backlight is shown as a lower side in the drawing, but may be an upper side.

In addition, this invention is not limited to the said 1st, 2nd embodiment, and is interpreted, Of course, it can change and improve suitably.

For example, the liquid crystal display device of this invention is not limited to the structure of FIG. 1, FIG. 2, and may contain another member, for example, the color filter between the liquid crystal cell 4 and the polarizers 2 and 6 You may arrange. In addition, you may give an anti-reflective process or a hard coat to the surface of the protective film of polarizer 2,6. Moreover, you may use what provided electroconductivity to a structural member. Moreover, when using as a transmission type, a cold cathode or a hot cathode fluorescent tube or the backlight which uses a light emitting diode, a field emission element, and an electroluminescent element as a light source can be arrange | positioned at the back surface. In this case, the arrangement of the backlight may be the upper side of FIGS. 1 and 2 or the lower side. In addition, a reflective polarizing plate, a diffusion 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 device of the present invention may be a reflection type, and in this case, only one polarizing plate may be disposed on the viewing side, and the rear side of the liquid crystal cell 4 or the lower side of the liquid crystal cell 4 may be used. The reflective film is disposed on the inner surface of the glass substrate 41. Of course, the front light using the said light source can also be provided in the liquid crystal cell visual recognition side.

[Example]

Hereinafter, although an Example and a comparative example are given and this invention is concretely demonstrated, this invention is not limited to these.

≪Production of Optical Compensation Films Z1 to Z9≫

As a sample of the 1st optical compensation film 3 in the said embodiment, optical compensation films Z1-Z9 as shown in following Table 1 were produced.

(Production of cellulose ester mixture)

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

10 parts by mass of additive 1

300 parts by mass of methylene chloride

Ethanol 52 parts by mass

The above was put into an airtight container, and after melt | dissolving completely, heating and stirring, Azumi filter paper No. of Azumi Rocca Co., Ltd. product was made. The cellulose ester mixture was prepared by filtration using 24. This mixture was filtered by FineMet NF manufactured by Nippon Seisen Corporation.

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

(Preparation of Silicon Dioxide Dispersion Diluent)

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

(Average Diameter 16nm, Apparent Specific Gravity 90g / L) of Primary Particles

80 parts by mass of ethanol

The above was stirred and mixed 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 mass parts of methylene chlorides were thrown into this silicon dioxide dispersion liquid, stirring and mixing with a dissolver for 30 minutes, and the silicon dioxide dispersion dilution liquid was produced.

(Manufacture of dope liquid 1)

10 mass parts of silicon dioxide dispersion dilution liquids were added with respect to 100 mass parts of cellulose ester mixtures obtained as mentioned above, and it was made to dope liquid 1.

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

Using a belt casting apparatus, the dope liquid 1 was uniformly cast on the stainless steel band support body at the temperature of 35 degreeC, and 1800 mm width. The solvent was evaporated until the residual solvent amount became 100% in the stainless band support, and peeled off from the stainless band support. The solvent of the web of the peeled cellulose-ester film was evaporated at 55 degreeC, and it extended | stretched 1.40 times in the width direction using the tenter, applying the heat of 140 degreeC-160 degreeC. The residual solvent at the start of stretching was 15%. Then, drying is complete | finished, conveying a drying zone of 130 degreeC with many rolls, the knurling process of width 15mm and an average height of 10 micrometers is given to the both ends of a film, the core is wound at the initial tension of 220N / m, and final tension of 110N / m. Was wound up to obtain a base film (biaxial film) A1 of an optical compensation film Z1 having a dry film thickness of 60 µm.

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

Moreover, as shown in Table 1 mentioned above, after producing dope liquid substantially similarly to base film A1 except having changed the cellulose ester species, the additive species, the additive amount, the film thickness, and the draw ratio in the width direction, Substrate films A2 to 5, 8 and 9 of optical compensation films Z2 to 5, 8 and 9 were produced.

However, "B" and "C" in the "resin" column of Table 1 represent the cellulose esters B and C in the said Table 2, and C is the average of the epsilon caprolactone grafted per 1 mol of glucose units specifically, The number of moles (MS) is 0.72, the average degree of substitution (DS) of the graft chain (grafted caprolactone) is 0.3, the average degree of polymerization (DPn) of ε-caprolactone of the graft chain is 5.4, and the average degree of substitution DS of hydroxyl groups ( OH) was used as 0.3. In addition, the "additive 2" in the "additive species" column shows the additive 2 (acrylic compound) in the said Table 3, and shows the acrylic compound specifically synthesize | combined as follows.

Synthesis of Acrylic Compound

Into a glass flask equipped with a stirrer, two dropping funnels, a gas introduction tube and a thermometer, 40 g of monomer Xa and Xb mixed liquids of the type and ratio (mole composition ratio) shown in Table 4 below, 2 g of mercaptopropionic acid as a chain transfer agent and 30 g of toluene were added. And it heated up at 90 degreeC. Then, azobisisobutyronitrile 0.4 dissolved in 14 g of toluene from the other funnel was added dropwise over 3 hours with the monomer Xa, Xb mixed liquid of the kind and ratio (molar composition ratio) shown in Table 4 from one dropping funnel over 3 hours. g was dripped over 3 hours. Thereafter, 0.6 g of azobisisobutyronitrile dissolved in 56 g of toluene was further added dropwise over 2 hours, and then the reaction was continued for 2 hours to obtain polymer X. The obtained polymer X was a solid at room temperature. The weight average molecular weight of polymer X is shown in Table 4 according to the following measuring method.

In addition, MMA and HEA of Table 4 are abbreviated-name of the following compounds, respectively.

MMA: Methyl methacrylate

HEA: 2-hydroxyethyl acrylate

(Weight average molecular weight measurement)

The measurement of the weight average molecular weight was measured using gel permeation chromatography.

Measurement conditions are as follows.

Solvent: Methylene Chloride

Column: Shodex K806, K805, K803G (used by connecting 3 Showa Denko Co., Ltd.)

Column temperature: 25 ° C

Sample concentration: 0.1% by mass

Detector: RI model 504 (made by GL Science)

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

Flow rate: 1.0ml / min

Calibration curve: Standard polystyrene STK Standard polystyrene (manufactured by Tosoh Corporation) Mw = 1000000 to 500 was used as a calibration curve with 13 samples. 13 samples are used at substantially equal intervals.

<Production of optical compensation film Z1>

By forming an intermediate | middle layer and a liquid crystal layer on the base film A1 obtained by making it above, the optical compensation film Z1 was produced as shown in Table 1 mentioned above.

(Formation of intermediate layer)

25 parts by mass of urethane acrylate oligomer

(UV-7510B, Nippon Kose Kagaku Co., Ltd.)

290 parts by mass of propylene glycol monomethyl ether

685 parts by mass of isopropyl alcohol

0.05 mass part of photoinitiators

(Lucirine TPO (product made by BASF Corporation))

This coating liquid was applied onto the base film A1 with a wire bar # 3, dried at 80 ° C. for 30 seconds, and then irradiated with ultraviolet light 120 mJ / mm for 10 seconds to form an intermediate layer. The film thickness of the intermediate | middle layer after drying was 0.5 micrometer.

(Formation of Liquid Crystal Layer (Anisotropic Layer))

20 parts by mass of ultraviolet polymerizable liquid crystal material

(UCL018, product made by Dainippon Ink Chemical Industries, Ltd.)

80 parts by mass of propylene glycol monomethyl ether acetate

0.04 mass part of photoinitiators

(Lucirine TPO (product made by BASF Corporation))

0.02 parts by mass of hindered amine

LS-765 (product made by Sanyo Life Technical Co., Ltd.)

0.03 parts by mass of vertical alignment agent

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

This polymeric liquid crystal layer coating liquid was apply | coated on the said intermediate | middle layer by the die coater. It heat-dried for 1 minute in 80 degreeC atmosphere, until the temperature of a liquid crystal layer became 65 degreeC, and then cooled rapidly to 28 degreeC, and orientated the liquid crystal material.

In addition, the solid-liquid phase transition temperature of the ultraviolet-polymerizable liquid crystal compound was 23 degreeC, and it confirmed beforehand that the liquid crystal phase-isotropic liquid phase transition temperature is 70 degreeC.

After orienting the liquid crystal material, the liquid crystal layer was irradiated with ultraviolet light of 250 mJ / mm for 10 seconds at an oxygen concentration of 0.2% and a temperature of 28 ° C. to cure the polymerizable liquid crystal composition to form a liquid crystal layer. The thickness of the liquid crystal layer was 1.2 μm.

<Production of Optical Compensation Films Z2 to 4, 8, 9>

As shown in Table 1, using the base films A2 to 4, 8 and 9, except that the liquid crystal film thickness was changed, the optical compensation films Z2 to 4, 8 and 9 were produced in almost the same manner as the optical compensation film Z1. It was.

<Production of optical compensation film Z5>

As shown in Table 1 above, the base film A5 was used as the optical compensation film Z5 as it is.

<Production of optical compensation film Z6>

Except for setting the draw ratio in the width direction to 1.01 times and setting the film thickness to 150 µm, the shrinkable film (Toray ( Ltd. product, a brand name "trepan BO2873" were bonded. Thereafter, the film length direction was maintained by a roll stretching machine, and the film was stretched 1.5 times in the length direction in an air circulation oven at 180 ° C., and then the shrinkable film was peeled off together with the acrylic pressure-sensitive adhesive layer to prepare an optical compensation film Z6.

<Production of optical compensation film Z7>

Shrinkage through an acrylic adhesive layer (thickness 15 μm) on both sides of Zeonoa ZF-14-100 (average refractive index = 1.52, Tg = 136 ° C., Ro = 3.0 nm, Rth = 5.0 nm, manufactured by Optes) The film (Toray Corporation make, brand name "trepan BO2873") was bonded. Thereafter, the film length direction was maintained with a roll stretching machine, the film was stretched 1.38 times in the length direction in an air circulation oven at 146 ° C., and after stretching, the shrinkable film was peeled together with the acrylic pressure-sensitive adhesive layer to prepare an optical compensation film Z7. .

`` Production of Optical Compensation Films C1 to C8 ''

As a sample of the 2nd optical compensation film 5 in the said embodiment, the optical compensation films C1-C8 as shown in following Table 5 were produced.

Specifically, except for changing the cellulose ester species, the additive species, the additive amount and the film thickness, and applying the conveyance tension after stretching in the width direction in the tenter, and stretching in the longitudinal direction as well, the optical film was prepared in the same manner as in the preparation of the base film A1. Compensation films C1 to C8 were produced. The additive species in Table 5 are as shown in Table 3, the DSP value increasing agent 1 represents an aromatic terminal polyester compound 18, and the DSP value increasing agent represents a triazine compound.

≪Evaluation of the optical compensation film≫

<Measurement of Retardation Value Ro, Rth>

The retardation value of the optical compensation films Z1-Z9 and C1-C8 was measured using the automatic birefringence meter (Oji Keisukuki Co., Ltd. make, Cobra-21ADH).

Specifically, the optical compensation film was subjected to three-dimensional refractive index measurement at 10 locations at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH, and the average values of the refractive indices nx, ny and nz were obtained. Accordingly, 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) × d

Rth = {(nx + ny) / 2-nz} × d

In the formula, Ro is a film in-plane retardation value, Rth is a film thickness direction retardation value, nx is a refractive index in the slow axis direction in the film plane, ny is a refractive index in the fast axis direction in the film plane, nz is a film thickness direction The refractive index of d represents the thickness (nm) of the film.

From the values of the retardation values Ro1 and Rth1 of the first optical compensation layer in Table 6, the optical compensation films Z1 to Z4, Z6, Z8, and Z9 according to the present invention are Ro> 0, and -Ro / 2 <Rth <Ro / Since 2, nx1> nz1> ny1 ((Equation 1)) is satisfied.

Further, since the optical compensation films C1 to C6 according to the present invention are Ro≥0 and Rth> Ro / 2 from the values of the retardation values Ro2 and Rth2 of the second optical compensation layer, nx2≥ny2> nz2 (: It can be seen that 2) is satisfied.

In addition, it can be seen that the optical compensation layers used in the liquid crystal display devices 1 to 8 of the present invention satisfy DSP (Ro1) < 1 < DSP (Rth2) (Equation 3) as wavelength dispersion.

≪Production of Polarizing Plate≫

The polyvinyl alcohol film of 120 micrometers in thickness was uniaxially stretched (temperature 110 degreeC, draw ratio 5 times). This was immersed in the aqueous solution which consists of 0.075g of iodine, 5g of potassium iodide, and 100g of water for 60 second, and then immersed in the 68 degreeC aqueous solution which consists of 6g of potassium iodide, 7.5g of boric acid, and 100g of water. This was washed with water and dried to obtain a polarizer.

Subsequently, according to the following steps 1 to 5, optical compensation films Z1 to 9 or optical compensation films C1 to 8 on the surface side of the polarizer, and Konica Minolta Tack KC4UY (cellulose ester film manufactured by Konica Minolta Opto Co., Ltd.) on the back side, respectively, were polarizing plates. It bonded together as a protective film and produced polarizing plates Z11-19 and C11-18. However, about the optical compensation films Z1-4, 8, 9, it bonded to the polarizer so that a base film side might become a polarizer side (the liquid crystal layer side was the opposite side of a polarizer).

Step 1: The film (optical compensation film, cellulose ester film) was immersed in 60 mol of 2 mol / L sodium hydroxide solution for 90 second, and then water-washed and dried to obtain the film which saponified the side joined with a polarizer.

Process 2: The said polarizer was immersed for 1-2 second in the polyvinyl alcohol adhesive tank of 2 mass% of solid content.

Process 3: The excess adhesive adhering to the polarizer in process 2 was lightly wiped and removed, and this was sandwiched between the optical compensation film and the cellulose ester film which were processed in process 1, and were laminated.

Process 4: The laminated body laminated | stacked at the process 3 was bonded by the pressure of 20-30 N / cm <^2> , conveyance speed about 2 m / min.

Process 5: The sample bonded at the process 4 in 80 degreeC dryer was dried for 2 minutes, and polarizing plates Z11-19 and C11-18 were produced.

≪Production of liquid crystal display device≫

A commercially available 32 type MVA type liquid crystal television ("AQUOS32AD5" manufactured by Sharp, "AQUOS" is a registered trademark) is peeled off, and the above-mentioned polarizing plates Z11 to 19 and C11 to 18 are combined so that they are the combination of Table 6, respectively. It adhere | attached on both surfaces, and produced liquid crystal display devices (1)-(11). At this time, the bonding direction of the polarizing plate was such that the absorption axis was directed in the same direction as the polarizing plate previously bonded at the time of purchase so that the optical compensation film side (the side opposite to the Konica Minolta tag KC4UY) was the liquid crystal cell side.

The following evaluation was performed using the liquid crystal display devices (1)-(11) produced as mentioned above.

≪Evaluation of liquid crystal display device≫

<Evaluation of the viewing angle>

After lighting the backlight of each liquid crystal display device continuously for 1 week in 23 degreeC and 55% RH environment, the viewing angle was measured. For the measurement, the EZ-contrast 160D manufactured by ELDIM was used to measure the ratio A of the luminance of the black display and the white display in the directions of 45 °, 135 °, 225 °, 315 °, and 70 ° inclination angle, and averaged values. Was used. The measurement results were evaluated according to the following criteria, and were as shown in Table 6 above. In addition, in this evaluation standard, "(triangle | delta)" means a thing within a practically permissible range, and "x" means that it is outside a permissible range practically.

◎: 100 <A

△: 50 <A≤100

×: A≤50

<Front Contrast>

The backlight of each liquid crystal display device is turned on in an environment of 23 ° C. and 55% RH, the luminance from the normal direction of the display screen of the white display and the black display is measured, and the ratio is the front contrast, according to the following criteria. As a result, it was as shown in Table 6 above. CS-2000 manufactured by Konica Minolta Sensing Corporation was used for the measurement. Moreover, when front contrast exceeds 1000, it is an excellent liquid crystal display device. In addition, in this evaluation standard, "(triangle | delta)" means a thing within a practically permissible range, and "x" means that it is outside a permissible range practically.

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

◎: 1000 <front contrast

○: 750 <front contrast ≤ 1000

Δ: 500 <front contrast≤750

×: front contrast≤500

<Evaluation of color shift when viewed from the tilt direction>

About each liquid crystal display device, the black display state in the dark room was visually confirmed by the plural number of people from the inclination direction, and it evaluated as follows, and it was as having shown in Table 6 above. In addition, in this evaluation standard, "(triangle | delta)" means a thing within a practically permissible range, and "x" means that it is outside a permissible range practically.

◎: 0 out of 10 admit coloring

○: 1 to 2 of 10 recognized coloring

(Triangle | delta): 3-5 of 10 recognize coloring.

×: 5 to 10 of 10 recognized coloring

<Comprehensive Evaluation>

From the above results, in the liquid crystal display devices (1) to (8) as examples of the present invention, unlike the liquid crystal display devices (9) to (11) as the comparative examples, when the viewing angle is enlarged, the front contrast is improved, and the tilt direction is seen. It was found that the prevention of color shift is achieved at the same time and is excellent.

Considering this point, first, Rth of the rod-shaped liquid crystal in the VA-mode liquid crystal cell is negative, and the wavelength dispersion is positive, so that light leakage of the liquid crystal cell (light due to the phase difference in the liquid crystal cell in the thickness direction) is obtained. In order to eliminate the leakage, it is considered that an optical compensation layer of a C plate having a positive Rth and a positive wavelength dispersion similarly to a liquid crystal cell is required. On the other hand, in order to compensate for the light leakage of the polarizer (light leakage due to not being orthogonal when the transmission axes of the two polarizers are viewed from the oblique direction), it is desirable to obtain the same compensation effect at each wavelength, and as the wavelength increases, It is thought that the optical compensation layer of the Z plate of reverse wavelength dispersion which also becomes large in phase difference is suitable. Therefore, according to the structure of this invention which combined the optical compensation layer of C plate which has positive wavelength dispersion, and the optical compensation layer of Z plate of reverse wavelength dispersion, the compensation of the light leakage resulting from a liquid crystal cell and a polarizing plate together It is presumed that the color shift, the viewing angle, and the front contrast in the case of viewing from the inclined direction are attained.

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)

At least a first polarizer, a first optical compensation layer, a liquid crystal cell, a second optical compensation layer, and a second polarizer in this order;
The first and second optical compensation layers satisfy the following Equations 1 to 3,
Liquid crystal molecules in said liquid crystal cell are oriented in the thickness direction of the said liquid crystal cell at the time of black display, The liquid crystal display device characterized by the above-mentioned.
<Equation 1>
nx1>nz1> ny1
&Quot; (2) &quot;
nx2≥ny2> nz2
<Equation 3>
DSP (Ro1) <1 <DSP (Rth2)
Where nx1 is a refractive index in the in-plane slow axis direction of the first optical compensation layer, ny1 is a refractive index in the fast axis direction in the plane of the first optical compensation layer, and nz1 is a refractive index in the thickness direction of the first optical compensation layer. Nx2 is a refractive index in the in-plane slow axis direction of the second optical compensation layer, ny2 is a refractive index in the in-plane fastening direction of the second optical compensation layer, and nz2 is a thickness direction of the second optical compensation layer. Refractive indexes are respectively represented, Ro1 represents an in-plane retardation value of the first optical compensation layer represented by Equation 8-1, and Rth2 represents a thickness direction of the second optical compensation layer represented by Equation 9-2. DSP (Ro1) is a wavelength dispersion value of the in-plane retardation value Ro1 of the first optical compensation layer, and the in-plane retardation value Ro1 of the first optical compensation layer measured at a wavelength of 480 nm. In-plane retardation measured at 630 nm DSP (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. Divided by the retardation value Rth2 measured at a wavelength of 630 nm.)
<Equation 8-1>
Ro1 = (nx1-ny1) × d1
<Equation 9-2>
Rth2 = {(nx2 + ny2) / 2-nz2} × d2)
(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) The liquid crystal display of claim 1, wherein the first optical compensation layer comprises a cellulose resin layer. The method of claim 1 or 2, wherein the first optical compensation layer satisfies Equations 4 and 5,
And the second optical compensation layer satisfies Equations 6 and 7 below.
<Equation 4>
Ro1 = 50-100 [nm]
<Equation 5>
| Rth1 | = 0-20 [nm]
&Quot; (6) &quot;
Ro2 = 0-20 [nm]
&Quot; (7) &quot;
Rth2 = 200-350 [nm]
(Where Rth1 represents a retardation value in the thickness direction of the first optical compensation layer represented by Equation 9-1 below, and Ro2 represents an in-plane ritata of the second optical compensation layer represented by Equation 8-2 shown below. Indicates a datum value, and Ro2 and Rth1 are measured at a wavelength of 590 nm, respectively.)
<Equation 8-2>
Ro2 = (nx2-ny2) × d2
<Equation 9-1>
Rth1 = {(nx1 + ny1) / 2-nz1} × d1) The method of claim 1, wherein the first optical compensation layer includes at least a cellulose resin layer and a liquid crystal layer,
The cellulose resin layer,
It is arrange | positioned at the said 1st polarizer side rather than the said liquid crystal layer,
A liquid crystal display device having an in-plane retardation and having a slow axis orthogonal to an absorption axis of the first polarizer. The method of claim 1, wherein the first optical compensation layer includes at least a cellulose resin layer and a liquid crystal layer,
The cellulose resin layer,
It is arrange | positioned at the said liquid crystal cell side rather than the said liquid crystal layer,
A liquid crystal display device having an in-plane phase difference and having a slow axis parallel to an absorption axis of the first polarizer. The method according to any one of claims 1 to 5, wherein the second optical compensation layer,
A liquid crystal display device comprising a cellulose resin layer containing a DSP value increasing agent.

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