JP2000249835A - Optical compensation sheet, elliptical polarization plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical compensation sheet suitable for a liquid crystal display device in which the average tilt angle between the major axial direction of rodlike liquid crystal molecules of the liquid crystal cell and the substrate surface is <50 deg. for a black display. SOLUTION: Transparent supporting bodies 13a, 13b substantially having optically negative uniaxial properties and having optical axes substantially parallel to the plane of the transparent supporting bodies are used as optical compensation sheets. Or, optically anisotropic layers 12a, 12b having the following property are used as optical compensation sheets. In these layers 12a, 12b, discotic liquid crystal molecules are aligned in such a manner that the average tilt angle between the disk faces of discotic liquid crystal molecules and the planes of the transparent supporting bodies ranges from 5 deg. to 85 deg. and that the larger the distance between the discotic liquid crystal molecules and the surface of the transparent supporting bodies 13a, 13b is, the smaller becomes the tilt angle between the disk faces of the discotic liquid crystal molecules and the plane of the transparent supporting bodies 13a, 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical compensatory sheet having an optically anisotropic layer formed from discotic liquid crystalline molecules on a transparent support. Further, the present invention, a transparent protective film, a polarizing film, a transparent support and an optically anisotropic layer,
The present invention also relates to an elliptically polarizing plate laminated in this order. Further, the present invention also relates to a transmission type liquid crystal display device comprising a liquid crystal cell, a pair of polarizing elements disposed on both sides thereof, and an optical compensation sheet disposed between the liquid crystal cell and one or both polarizing elements. Furthermore, the present invention also relates to a reflective liquid crystal display device in which a liquid crystal cell, an optical compensation sheet, and a polarizing element are stacked in this order.

[0002]

2. Description of the Related Art A transmission type liquid crystal display device comprises a liquid crystal cell and two polarizing elements disposed on both sides thereof. The reflection type liquid crystal display device includes a liquid crystal cell and a polarizing element. The liquid crystal cell is composed of rod-like liquid crystal molecules and two substrates for enclosing the molecules. The substrate is provided with a transparent electrode for applying a voltage to the rod-like liquid crystalline molecules and an alignment film for aligning the rod-like liquid crystalline molecules. About the liquid crystal cell,
Various display modes in which the alignment state of the rod-like liquid crystalline molecules is different have been proposed. As a transmission type liquid crystal display device, TN
(Twisted Nematic), IPS (In-Plane Switchin)
g), FLC (Ferroelectric Liquid Crystal), OC
B (Optically Compensatory Bend), ECB (Electri
cally Controlled Birefringence), STN (Supper T
wisted Nematic) or VA (Vertically Aligned)
A mode has been proposed. A HAN (Hybrid Aligned Nematic) mode has been proposed as a reflective liquid crystal display device.

[0003] US Pat. No. 4,583,825 describes that
A transmission type liquid crystal display device using the above OCB mode liquid crystal cell is disclosed. In the OCB mode liquid crystal cell,
The rod-like liquid crystal molecules are symmetrically oriented with the middle of the two alignment films as the symmetry plane, and the tilt angle in the major axis direction of the rod-like liquid crystal molecules is minimized (nearly horizontal alignment) near the two alignment films and the two. It changes continuously so that it becomes maximum (substantially vertical alignment) in the middle of one alignment film. Since the rod-like liquid crystal molecules are symmetrically aligned as described above, the OCB mode liquid crystal cell has a self-optical compensation function. Therefore, a transmissive liquid crystal display device using an OCB mode liquid crystal cell is characterized by a wide viewing angle.

[0004] US Pat. No. 5,410,422 discloses that O
An improved invention of a transmission type liquid crystal display device using a symmetric type liquid crystal cell such as a CB mode is disclosed. US Patent 541
FIG. 12B of the specification of No. 0422 shows a symmetric liquid crystal cell other than the known OCB mode liquid crystal cell (FIG. 12C).
The rod-like liquid crystalline molecules are symmetrically oriented with the middle of the two alignment films as the symmetry plane. A liquid crystal cell which is continuously changed so as to be minimum (substantially horizontal alignment) in the middle of one alignment film is illustrated. However,
U.S. Pat. No. 5,410,422 does not describe at all how to align rod-like liquid crystal molecules and how to specifically configure a liquid crystal display device.

[0005]

As a result of research, the present inventor has found that rod-like liquid crystal molecules are symmetrically oriented with the middle of the two alignment films as the plane of symmetry, and that the rod-like liquid crystal molecules are oriented in the major axis direction. A liquid crystal display device using a liquid crystal cell in which the tilt angle is continuously changed so that the tilt angle is maximum (nearly vertical alignment) near the two alignment films and minimum (nearly horizontal alignment) between the two alignment films. Was successfully realized. No particular name is defined for the liquid crystal cell in the above alignment state. In this specification,
The liquid crystal cell in this alignment state is called a splay alignment cell. When the present inventor examined the performance of a liquid crystal display device using a splay alignment cell, it has a wide viewing angle. It is considered that a wide viewing angle is obtained by the self-optical compensation function of the symmetric liquid crystal cell. Further, when this liquid crystal display device was compared with a liquid crystal display device using an OCB mode liquid crystal cell which is a conventionally known symmetric liquid crystal cell, it was found that the display contrast was high and the response speed was high. The liquid crystal display device using the splay alignment cell is characterized by having a wide viewing angle, but it is expected that the viewing angle can be further expanded by using an appropriate optical compensation sheet. However, when the present inventor investigated, it was not possible to effectively optically compensate the above-mentioned liquid crystal display device with the conventionally proposed optical compensation sheet. Also,
When using the conventionally proposed optical compensation sheet,
The problem that front contrast fell was recognized. Therefore, the present inventors have started the development of a new optical compensation sheet suitable for a liquid crystal display device using a splay alignment cell.

An object of the present invention is to provide an optical compensatory sheet and an elliptically polarizing plate suitable for a liquid crystal display device in which the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °. It is to provide. Another object of the present invention is to provide a liquid crystal display device having a high display contrast, a wide viewing angle, and capable of high-speed display.

[0007]

The object of the present invention is to provide the following optical compensation sheets (1) to (3), (8) to (9), and the following (4) to (5), (10) to ( 11) elliptically polarizing plate,
And the following liquid crystal display devices (6) to (7) and (12) to (13). (1) An optical compensatory sheet having an optically anisotropic layer formed of discotic liquid crystalline molecules on a transparent support, wherein the transparent support substantially has optical negative uniaxiality. An optical compensatory sheet, the optical axis of which is substantially parallel to the plane of the transparent support. (2) The optical compensation sheet according to (1), wherein the transparent support comprises a polystyrene film. (3) The average inclination angle between the disc surface of the discotic liquid crystalline molecules in the optically anisotropic layer and the plane of the transparent support is 5 to 8
When the distance between the discotic liquid crystal molecules and the surface of the transparent support increases, the angle of the discotic liquid crystal molecules decreases so that the inclination angle between the disc surface of the molecules and the plane of the transparent support decreases. The optical compensation sheet according to (1), wherein the molecules are oriented. (4) a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer formed from discotic liquid crystalline molecules,
An elliptically polarizing plate laminated in this order, wherein the transparent support substantially has an optical negative uniaxial property, and its optical axis is substantially parallel to the support plane. Elliptically polarizing plate. (5) The elliptically polarizing plate according to (4), wherein the angle between the optical axis of the transparent support and the polarization axis of the polarizing film is substantially 45 °.

(6) A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, a pair of polarizing elements disposed on both sides of the liquid crystal cell, and a liquid crystal cell disposed between the liquid crystal cell and one or both polarizing elements. A transmission type liquid crystal display device comprising an optical compensation sheet, wherein the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °, wherein the optical compensation sheet comprises: A transparent support and an optically anisotropic layer formed from discotic liquid crystal molecules are laminated in order from the outside, and the transparent support substantially has an optical negative uniaxial property, A liquid crystal display device, wherein the axis is substantially parallel to the plane of the transparent support. (7) A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, an optical compensation sheet, and a polarizing element are laminated in this order, and the long axis of the rod-like liquid crystal molecules of the liquid crystal cell in black display. A reflective liquid crystal display device in which the average inclination angle between the direction and the substrate surface is less than 50 °, wherein the optical compensation sheet is formed from a transparent support and discotic liquid crystal molecules in order from the polarizing element side. An anisotropic layer is laminated, the transparent support has substantially optical negative uniaxiality, and its optical axis is substantially parallel to the plane of the transparent support. Liquid crystal display device.

(8) An optical compensatory sheet having an optically anisotropic layer formed of discotic liquid crystalline molecules on a transparent support, wherein the optically anisotropic layer contains discotic liquid crystalline molecules in a circle. When the average inclination angle between the disc surface and the plane of the transparent support is 5 to 85 ° and the distance between the discotic liquid crystal molecules and the surface of the transparent support increases, the disc surface of the discotic liquid crystal molecules and the transparent support become An optical compensatory sheet characterized in that the discotic liquid crystalline molecules are oriented so that the angle of inclination with respect to the plane is small. (9) The optically anisotropic layer further comprises a cellulose ester in an amount of 0.1 to 5% by weight based on the amount of the discotic liquid crystalline molecules.
The optical compensatory sheet according to (8), which contains the fluorine-containing surfactant in an amount of 0.01 to 30% by weight based on the amount of the discotic liquid crystalline molecules. (10) An elliptically polarizing plate in which a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer formed from discotic liquid crystal molecules are laminated in this order, wherein the optically anisotropic layer is When the average tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the transparent support is 5 to 85 °, and the distance between the discotic liquid crystal molecules and the surface of the transparent support increases, the discotic liquid crystal becomes An elliptically polarizing plate, wherein the discotic liquid crystal molecules are oriented so that the inclination angle between the disk surface of the hydrophilic molecules and the plane of the transparent support becomes small. (11) The angle between the average direction of a line obtained by projecting the normal of the discotic liquid crystal molecules on the plane of the transparent support and the polarization axis of the polarizing film is substantially 45 °. Elliptically polarizing plate.

(12) A liquid crystal cell in which rod-like liquid crystalline molecules are sealed in a gap between two substrates, a pair of polarizing elements disposed on both sides of the liquid crystal cell, and a liquid crystal cell disposed between the liquid crystal cell and one or both polarizing elements. A transmission type liquid crystal display device comprising an optical compensation sheet, wherein the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °, wherein the optical compensation sheet comprises: In order from the outside, a transparent support and an optically anisotropic layer formed from discotic liquid crystalline molecules are laminated, and the disc surface of the discotic liquid crystalline molecules in the optically anisotropic layer and the transparent support When the average inclination angle with respect to the plane is 5 to 85 ° and the distance between the discotic liquid crystalline molecules and the surface of the transparent support increases,
A liquid crystal display device wherein the discotic liquid crystal molecules are oriented so that the inclination angle between the disc surface of the discotic liquid crystal molecules and the plane of the transparent support becomes small. (13) A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, an optical compensation sheet, and a polarizing element are laminated in this order, and the long axis of the rod-like liquid crystal molecules of the liquid crystal cell in black display. A reflective liquid crystal display device in which the average inclination angle between the direction and the substrate surface is less than 50 °, wherein the optical compensation sheet is formed from a transparent support and discotic liquid crystal molecules in order from the polarizing element side. An optically anisotropic layer, wherein the average tilt angle between the disc surface of the discotic liquid crystal molecules in the optically anisotropic layer and the plane of the transparent support is 5 to 85 °, It is noted that when the distance between the molecule and the surface of the transparent support increases, the discotic liquid crystal molecules are oriented so that the tilt angle between the discotic liquid crystal molecule disc surface and the plane of the transparent support decreases. A liquid crystal display device. In this specification, “substantially perpendicular”, “substantially parallel”, or “substantially 45 °” means that the angle is within a range of ± 5 ° from a strict angle. This range is preferably less than ± 4 °, more preferably less than ± 3 °, even more preferably less than ± 2 °, and
Most preferably, it is less than 1 °.

[0011]

The present inventor has proposed an optical system having an optically anisotropic layer formed from discotic liquid crystal molecules on a transparent support in order to optically compensate a liquid crystal display device using a splay alignment cell. The use of a compensation sheet was considered. As a result, it was found that it is necessary to improve the conventional optical compensatory sheet for at least one (preferably both) of the transparent support and the optically anisotropic layer. Conventionally, as the transparent support, an optically isotropic film (eg, a triacetyl cellulose film) or an optically positive uniaxial film (eg, a stretched polycarbonate film) has been used. However, as a result of the present inventor's research, the use of a transparent support having substantially optical negative uniaxiality, the optical axis of which is substantially parallel to the plane of the transparent support, has been developed. It turned out to be suitable for optical compensation of the alignment cell. With respect to the alignment state of the discotic liquid crystal molecules in the optically anisotropic layer, conventionally, the average tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the polymer film is 5 to 85 °, When the distance between the liquid crystal molecules and the surface of the polymer film is increased, the orientation (hybrid alignment) is generally performed such that the tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the polymer film increases. However, as a result of the research by the present inventors, the average tilt angle between the discotic liquid crystal molecules and the plane of the polymer film is 5 to 85 °, and the distance between the discotic liquid crystal molecules and the surface of the polymer film is small. It has been found that when the size is increased, the orientation (inverse hybrid orientation) is more suitable for the optical compensation of the splay alignment cell, so that the inclination angle between the discotic liquid crystal molecules and the plane of the polymer film becomes smaller.

The present inventor further studied the above-described optical compensation sheet, and found that not only the splay alignment cell but also various liquid crystal cells could be optically compensated effectively. That is, the above optical compensation sheet can be effectively used in a liquid crystal display device in which the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °. Specifically, in addition to the splay alignment liquid crystal cell, a TN mode, STN mode, ECB mode or HAN mode liquid crystal cell can be effectively optically compensated.
As a result, by using the optical compensation sheet of the present invention in a liquid crystal display device, an image having a high display contrast and a wide viewing angle can be displayed at a high speed.

[0013]

FIG. 1 is a cross-sectional view schematically showing the orientation of a liquid crystal compound in a splay alignment liquid crystal cell. As shown in FIG. 1, the splay alignment liquid crystal cell includes a lower substrate (4
a), a lower transparent electrode (3a), a lower alignment film (2a), a liquid crystal layer (1), an upper alignment film (2b), an upper transparent electrode (3b), and an upper substrate (4b). Have. As the rod-like liquid crystal molecules (1a to 1h) used in the liquid crystal layer (1), rod-like nematic liquid crystal molecules having negative dielectric anisotropy are used. The alignment films (2a, 2b) have a function of vertically aligning the rod-like liquid crystal molecules (1a to 1h). R
Da and RDb are rubbing directions of the alignment film. As shown in FIG. 1, the rubbing directions of the two alignment films are substantially parallel. The transparent electrodes (3a, 3b) have a function of applying a voltage to the rod-like liquid crystal molecules (1a to 1h).

When the voltage applied to the splay alignment liquid crystal cell is low, as shown in off of FIG.
The rod-shaped liquid crystalline molecules (1a to 1d) on the a) side and the upper substrate (4
The rod-like liquid crystalline molecules (1e to 1h) on the b) side are oriented substantially in the opposite direction (vertically symmetric) with the middle (XX) of the two alignment films as the plane of symmetry. In addition, the substrates (4a, 4a,
b) The rod-like liquid crystal molecules (1a, 1h) in the vicinity are oriented so that the tilt angle in the long axis direction becomes maximum (substantially vertical), and the rod-like liquid crystal in the middle of the two alignment films (near XX). Sex molecules (1
d, 1e) are oriented such that the inclination angle in the long axis direction is minimum (substantially horizontal). The intermediate rod-like liquid crystal molecules (1b, 1c, 1f, 1g) have their tilt angles in the major axis direction continuously changing. As shown in on in FIG. 1, when the applied voltage is high, the rod-like liquid crystalline molecules (1a, 1h) near the substrates (4a, 4b) remain aligned almost vertically. Further, the rod-like liquid crystal molecules (1d, 1e) in the middle (near XX) of the two alignment films also remain substantially horizontally aligned.
The liquid crystal molecules (1b, 1c, 1f, 1g) located in the middle of the liquid crystal molecules change their orientation with an increase in the voltage, and they are more horizontally oriented than in the off state. However, the rod-like liquid crystal molecules (1a to 1d) on the lower substrate (4a) side of the liquid crystal cell and the rod-like liquid crystal molecules (1e to 1h) on the upper substrate (4b) side are located in the middle (X) of the two alignment films. The orientation in the substantially opposite direction (vertically symmetric) with -X) as the plane of symmetry is the same as in the off state.

FIG. 2 is a schematic diagram of a liquid crystal display device using a splay alignment liquid crystal cell. The liquid crystal display device shown in FIG. 2 includes a splay alignment liquid crystal cell (10), a pair of polarizing elements (11a, 11b) provided on both sides of the liquid crystal cell, and a pair of optical elements disposed between the liquid crystal cell and the polarizing plate. It consists of compensation sheets (12a, 12b) and backlight (BL). The optical compensation sheets (12a, 12b) may be arranged only on one side. The splay alignment liquid crystal cell (10) corresponds to the liquid crystal cell shown in FIG. The upper and lower rubbing directions (RDa, RDb) of the liquid crystal cell (10) are the same direction (parallel). The direction of the polarization axis of the lower polarizing element (11a) (P
Aa) and the rubbing direction (R) of the alignment film of the liquid crystal cell (10).
The angle with Da, RDb) is 45 °. The direction of the polarization axis (PAb) of the upper polarizing element (11a) and the liquid crystal cell (1
The angle from the rubbing direction (RDa, RDb) of the alignment film of (0) is also 45 °. The direction (PAa) of the polarization axis of the lower polarizing element (11a) and the direction (PAb) of the polarization axis of the upper polarizing element (11a) are orthogonal to each other, and are in a crossed Nicols arrangement. Arrows (RDc, RDd) shown on the optical compensation sheets (12a, 12b) correspond to the rubbing direction of the discotic liquid crystal molecules of the optically anisotropic layer.

FIG. 3 is a conceptual diagram showing optical compensation of a splay alignment liquid crystal cell by an optical compensation sheet. If the splay alignment liquid crystal cell is optically compensated using an optical compensation sheet, the viewing angle of the splay alignment liquid crystal cell can be further increased. The optical compensation sheet comprises a transparent support and a layer formed from discotic liquid crystalline molecules. In FIG. 3A, a splay-aligned liquid crystal cell (10) is provided with an optically anisotropic layer (12a, 12a, 12b) formed from discotic liquid crystal molecules.
Optically compensated according to 12b). Transparent support (13
a, 13b) are optically isotropic. Rubbing direction (RDc, RDd) of optically anisotropic layer (12a, 12b)
In the rubbing direction (R) of the splay alignment liquid crystal cell (10).
Da, RDb) and antiparallel relationship,
The rod-like liquid crystal molecules of the liquid crystal cell (10) correspond to the discotic liquid crystal molecules of the optically anisotropic layers (12a, 12b) (a to f) to optically compensate.

As shown in FIG. 3B, when an optical compensatory sheet having a layer made of discotic liquid crystalline molecules provided on a transparent support having optical anisotropy is used, it is more effective to use an optical compensatory sheet. The splay alignment liquid crystal cell can be compensated optically. In FIG. 3B, the splay alignment liquid crystal cell (10)
To a layer (1) formed from discotic liquid crystal molecules.
2a, 12b) and a transparent support having optical anisotropy (1
3a, 13b) cooperate to optically compensate. The rod-like liquid crystal molecules of the liquid crystal cell (10) and the optically anisotropic layer (12
Correspondences (a to f) of a, 12b) with discotic liquid crystalline molecules are the same as those in FIG. For the rod-like liquid crystal molecules that are aligned substantially horizontally at the center of the splay alignment liquid crystal cell (10), a transparent support (1
The optical anisotropy of 3a, 13b) is designed to correspond (g, h). In addition, the transparent support (13a, 13
The ellipse described in b) is a refractive index ellipse generated by the optical anisotropy of the transparent support.

FIG. 4 is a sectional view schematically showing the orientation of a liquid crystal compound in a HAN mode liquid crystal cell. As shown in FIG. 4, the liquid crystal cell in the HAN mode has a reflection plate (R
P), lower substrate (4a), lower transparent electrode (3a), lower alignment film (2a), liquid crystal layer (1), lower alignment film (2b), upper transparent electrode (3b), and upper substrate (4b) It has a structure arranged in order. Instead of providing the reflection plate (RP), the lower transparent electrode (3a) may be changed to a reflection electrode. As the rod-like liquid crystal molecules (1a to 1d) used in the liquid crystal layer (1), rod-like nematic liquid crystal molecules having negative dielectric anisotropy are used. The lower alignment film (2a) has a function of horizontally aligning the rod-like liquid crystalline molecules. The upper alignment film (2b)
It has the function of vertically aligning rod-like liquid crystalline molecules. RD
a is the rubbing direction of the lower alignment film. Transparent electrode (3)
Has a function of applying a voltage to the rod-like liquid crystal molecules (1a to 1d).

When the voltage applied to the HAN mode liquid crystal cell is low, the rod-like liquid crystal molecules (1a) near the lower substrate (4a) of the liquid crystal cell are tilted in the long axis direction as shown in FIG. Are minimized (substantially horizontal), and the rod-like liquid crystalline molecules (1d) near the upper substrate (4b) are oriented such that the long axis direction inclination angle is maximized (substantially vertical). The intermediate rod-like liquid crystal molecules (1b, 1c) have a continuous change in the tilt angle in the long axis direction. As shown in on in FIG. 4, when the applied voltage is high, the rod-like liquid crystalline molecules (1a) near the lower substrate (4a) remain aligned substantially horizontally.
Further, the rod-like liquid crystal molecules (1d) of the upper substrate (4b) also remain almost vertically aligned. The orientation of the liquid crystal molecules (1b, 1c) located between them changes when the voltage is increased, and these molecules are oriented more horizontally than in the off state.

FIG. 5 is a schematic diagram of a liquid crystal display device using a HAN mode liquid crystal cell. The liquid crystal display device shown in FIG. 5 includes a reflection plate (RP) and a HAN mode liquid crystal cell (1).
0), the optical compensation sheet (12), and the polarizing element (1)
1). The HAN mode liquid crystal cell (10) corresponds to the liquid crystal cell shown in FIG. The arrow (RDa) shown in the liquid crystal cell (10) is the rubbing direction of the liquid crystal cell. The angle between the direction of the polarization axis (PAb) of the polarizing element (11) and the rubbing direction (RDa) of the alignment film of the liquid crystal cell (10) is 45 °. The arrow (RDc) shown on the optical compensation sheet (12) corresponds to the rubbing direction of the discotic liquid crystalline molecules of the optically anisotropic layer.

FIG. 6 is a conceptual diagram showing optical compensation of a HAN mode liquid crystal cell by an optical compensation sheet. If the HAN mode liquid crystal cell is optically compensated using the optical compensation sheet, the viewing angle of the HAN mode liquid crystal cell can be further expanded. The optical compensation sheet comprises a transparent support and a layer formed from discotic liquid crystalline molecules. In FIG. 6A, a HAN mode liquid crystal cell (10) is optically compensated by an optically anisotropic layer (12) formed from discotic liquid crystalline molecules. Transparent support (13)
Is optically isotropic. By setting the rubbing direction (RDc) of the optically anisotropic layer (12a) to be parallel to the rubbing direction (RDa) of the HAN mode liquid crystal cell (10), the rod-like liquid crystal property of the liquid crystal cell (10) is improved. The molecules and the discotic liquid crystalline molecules of the optically anisotropic layer (12a) correspond (ac) to optically compensate.

As shown in FIG. 6B, when an optical compensatory sheet having a layer made of discotic liquid crystalline molecules on a transparent support having optical anisotropy is used, it is more effective to use an optical compensatory sheet. HAN mode liquid crystal cells can be optically compensated. In FIG. 6B, the HAN mode liquid crystal cell (1)
0) is optically compensated for in cooperation with the layer (12) formed of discotic liquid crystalline molecules and the transparent support (13) having optical anisotropy. The correspondence (ac) between the rod-like liquid crystalline molecules of the liquid crystal cell (10) and the discotic liquid crystalline molecules of the optically anisotropic layer (12) is the same as that shown in FIG. HAN mode liquid crystal cell (10)
The transparent support (13) is further designed so that the optical anisotropy of the rod-like liquid crystal molecules oriented substantially horizontally at the upper portion corresponds to (d). The ellipse drawn on the transparent support (13) is a refractive index ellipse caused by the optical anisotropy of the transparent support.

[Liquid Crystal Cell] The optical compensatory sheet of the present invention comprises:
It is effectively used in a liquid crystal display device in which the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °. Specifically, a splay alignment liquid crystal cell or a TN mode, STN mode, ECB mode or HAN mode liquid crystal cell can be optically compensated effectively. Splay alignment liquid crystal cell, TN mode liquid crystal cell,
This is particularly effective for ECB mode liquid crystal cells and HAN mode liquid crystal cells. As for liquid crystal cells other than the splay alignment cell, well-known liquid crystal cells can be used. Hereinafter, the spray alignment cell will be further described.

The substrate and the transparent electrode used in the splay alignment liquid crystal cell are the same as those in other known alignment mode liquid crystal cells. A commercially available product (for example, a glass substrate provided with an ITO transparent electrode) may be used. As the alignment film, a vertical alignment film having a function of substantially vertically aligning rod-like liquid crystalline molecules near the alignment film is used. Examples of the vertical alignment film of rod-like liquid crystal molecules include a solution coating type (including a liquid crystal dissolution injection type), a plasma polymerization type, and a sputtering type alignment film.
Examples of the solution coating type vertical alignment agent include lecithin, stearic acid, octadecylmalonic acid, hexadecyltrimethylammonium bromide, octadecylamine hydrochloride, monobasic chromium carboxylate complex (eg, chromium myristate complex, perfluorononane Acid chromium complexes) and organosilanes (eg, N, N-dimethyl-N-octadecyl-3-aminopropyltrimethoxysilyl chloride). Examples of plasma-polymerized vertical alignment agents include hexamethyldisiloxane, perfluorodimethylcyclohexane, and tetrafluoroethylene. Examples of the vertical alignment agent of the sputtering type include polytetrafluoroethylene. A rubbing process is performed on the formed vertical alignment film as shown in FIG. In the splay alignment liquid crystal cell, the rod-like liquid crystal molecules are completely vertically (9
Pretilt in a certain direction without orientation at 0 °). The pretilt direction of the rod-like liquid crystal molecules matches the direction of the rubbing treatment. The rubbing treatment can be performed in the same manner as a known treatment for an alignment film.

Two substrates provided with a transparent electrode and a vertical alignment film are bonded via a spacer so that the rubbing directions are parallel. In the gap created by the spacer,
A splay alignment liquid crystal cell is prepared by injecting rod-like liquid crystal molecules. As the rod-like liquid crystal molecules, nematic liquid crystal molecules having negative dielectric anisotropy are used. Examples of rod-like liquid crystalline molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenyl Includes pyrimidines, phenyldioxane, tolanes and alkenylcyclohexylbenzonitrile. The rod-like liquid crystal molecule is composed of two or more rings, a linking group connecting the rings, and a substituent thereof. It is known that the dielectric anisotropy is greatly affected by the linking group and the substituent. As a nematic liquid crystal molecule having a negative dielectric anisotropy, an alkylcyclohexylcarbonitrile compound is typical, and a commercially available product (for example, MJ95785, M
X94296, MJ941296) can also be used. It is preferable that the difference in retardation between on and off of the splay alignment liquid crystal cell be approximately half the wavelength of light. The splay alignment liquid crystal cell can be used in either a normally white mode in which black display is performed when on or a normally black mode in which black display is performed when off.

[Polarizing Element] A polarizing element generally comprises a polarizing film and transparent protective films disposed on both sides thereof. However, the transparent support of the optical compensation sheet described later can function as a transparent protective film on the liquid crystal cell side. In this case, a laminate in which a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer formed from discotic liquid crystalline molecules are laminated in this order functions as an elliptically polarizing plate. As a transparent protective film provided separately from the transparent support of the optical compensation sheet, an optically isotropic polymer film described later,
In particular, it is preferable to use a triacetyl cellulose film. The polarizing film includes an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, and a polyene-based polarizing film. The iodine-based polarizing film and the dye-based polarizing film are generally manufactured using a polyvinyl alcohol-based film. The polarization axis of the polarizing film is
This corresponds to a direction perpendicular to the stretching direction of the film. The directions of the polarization axes of the two polarizing elements are made substantially orthogonal. The angle between the direction of each polarization axis and the rubbing direction of the alignment film of the liquid crystal cell is adjusted to be substantially 45 °.

[Optical Compensation Sheet] In the transmission type liquid crystal display device, one or two optical compensation sheets are arranged between the liquid crystal cell and one or both polarizing elements. In the reflection type liquid crystal display device, one optical compensation sheet is disposed between the liquid crystal cell and the polarizing element. The optical compensatory sheet preferably has negative birefringence as an optical property. Further, it is preferable that the inclination angle of the optical axis with respect to the normal direction of the film is changed so as to be minimum on the liquid crystal cell side and maximum on the polarizing element side. The change in the tilt angle may be discontinuous. Further, the inclination angle of the optical axis is preferably 40 to 80 °. Furthermore, the average direction of the orthogonal projection of the optical axis onto the liquid crystal cell and the rubbing direction of the liquid crystal cell are preferably substantially parallel (0 °) or substantially antiparallel (180 °). The optical compensatory sheet of the present invention comprises (1) a laminate of an optically isotropic transparent support and an optically anisotropic layer formed from discotic liquid crystalline molecules, or (2)
It can be classified as a laminate of an optically anisotropic transparent support and an optically anisotropic layer formed from discotic liquid crystalline molecules. The optically anisotropic transparent support of (2) may be composed of a laminate of an optically anisotropic polymer film and an optically isotropic polymer film. Generally, the transparent support is disposed on the polarizing film side (outside), and the optically anisotropic layer is disposed on the liquid crystal cell side (inside). Hereinafter, an optically isotropic polymer film, an optically anisotropic polymer film, and an optically anisotropic layer formed from discotic liquid crystalline molecules will be described in this order.

[Optically Isotropic Polymer Film] The optically isotropic polymer film preferably has a light transmittance of 80% or more. Specifically, the optical isotropy has an in-plane retardation (Re) of preferably 10 nm or less, more preferably 5 nm or less.
The thickness direction retardation (Rth) is 40 n
m or less, more preferably 20 nm or less. The in-plane retardation (Re) and the retardation in the thickness direction (Rth) are respectively defined by the following equations. Re = (nx−ny) × d Rth = [{(nx + ny) / 2} −nz] × d where nx and ny are in-plane refractive indices of the polymer film, and nz is a thickness direction of the polymer film. Is the refractive index, and d is the thickness of the polymer film. As the optically isotropic polymer, the cellulose ester is preferably a cellulose ester, more preferably acetyl cellulose, and most preferably triacetyl cellulose. The polymer film is preferably formed by a solvent casting method. The thickness of the optically isotropic polymer film is preferably from 20 to 500 μm, more preferably from 50 to 200 μm.
In order to improve the adhesion between the optically isotropic polymer film and the layer provided thereon (adhesive layer, alignment film or optically anisotropic layer), the polymer film is subjected to a surface treatment (eg, glow discharge treatment, corona discharge). Treatment, ultraviolet (UV) treatment, and flame treatment). On the polymer film,
An adhesive layer (undercoat layer) may be provided.

[Optically Anisotropic Polymer Film] The optically anisotropic polymer film preferably has a light transmittance of 80% or more. Specifically, the term “anisotropic” means that the in-plane retardation (Re) is preferably 20 nm or more, and more preferably 40 nm or more. The thickness direction retardation (Rth) is 60 nm.
It is preferably at least 80 nm, more preferably at most 80 nm. Conventionally, as an optically anisotropic polymer film used in combination with an optically anisotropic layer formed from discotic liquid crystalline molecules, an aromatic ring on the main chain side such as polycarbonate, polysulfone or polyethersulfone has been used. A film substantially having optically positive uniaxiality and comprising a polymer having However, when the inventor studied a splay alignment cell,
It has been found that a film having substantially negative optical uniaxiality is suitable for optical compensation of a liquid crystal cell. The film having substantially optical negative uniaxiality can be formed from a polymer having an aromatic ring on a side chain such as polystyrene. In a polymer film having "substantially optically uniaxial", one optical axis is stronger than the other optical axis and can be regarded as substantially uniaxial even though it shows biaxiality. Polymer films are included. Preferably, the optical axis is substantially parallel to the plane of the polymer film. In other words, it is particularly preferable to use a polymer film having a refractive index ellipse shown in FIG. 3 or FIG. 6B.

The optically anisotropic polymer film is preferably formed from a styrene-based polymer. Styrene polymers include styrene and other vinyl monomers (eg,
Copolymers with acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, acrylamide, methacrylamide) and polymers of styrene derivatives (monomers in which the benzene ring of styrene is substituted) are included.
Optical anisotropy can be obtained by stretching a polymer film. The stretching direction and the direction of the optical axis are substantially parallel. Since the polymer film preferably has optical uniaxiality, uniaxial stretching is preferable. The direction of the optical axis is preferably substantially parallel to the rubbing direction of the discotic liquid crystalline molecules of the optically anisotropic layer described below. The thickness of the optically anisotropic polymer film is preferably 20 to 500 μm, more preferably 50 to 200 μm.
Is more preferable. In order to improve the adhesion between the optically anisotropic polymer film and the layer provided thereon (adhesive layer, alignment film or optically anisotropic layer), the polymer film is subjected to a surface treatment (eg, glow discharge treatment, corona discharge). Treatment, ultraviolet (UV) treatment, and flame treatment). An adhesive layer (undercoat layer) may be provided on the polymer film.

[Optical Anisotropic Layer] The optically anisotropic layer is formed from discotic liquid crystal molecules. It is preferable that the discotic liquid crystal molecules are fixed in the layer while keeping the alignment state. More preferably, the discotic liquid crystalline molecules are fixed by a polymerization reaction. Discotic liquid crystalline molecules are described in various literatures (C. Destrade et al., Mo.
l. Crysr. Liq. Cryst., vol. 71, page 111 (1981);
The Chemical Society of Japan, Quarterly Review of Chemistry, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al.,
Angew. Chem. Soc. Chem. Comm., Page 1794 (1985);
J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page
2655 (1994)). The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284. In order to fix the discotic liquid crystal molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystal molecules. However, when a polymerizable group is directly connected to the disc-shaped core,
It becomes difficult to maintain the alignment state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystal molecule is preferably a compound represented by the following formula (I).

(I) D (-LP) _{n wherein} D is a discotic core; L is a divalent linking group; P is a polymerizable group; and n is 4 to 12 Is an integer. An example of the discotic core (D) of the formula (I) is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L) and a polymerizable group (P).

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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In the formula (I), the divalent linking group (L)
Is an alkylene group, alkenylene group, arylene group,-
It is preferably a divalent linking group selected from the group consisting of CO-, -NH-, -O-, -S- and a combination thereof. The divalent linking group (L) includes an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-,-
More preferably, the group is a group obtained by combining at least two divalent groups selected from the group consisting of O- and -S-. The divalent linking group (L) is most preferably a group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO- and -O-. The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 6 to 10 carbon atoms. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group, a halogen atom, a cyano, an alkoxy group, an acyloxy group). Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (P). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group.

L1: -AL-CO-O-AL- L2: -AL-CO-O-AL-O- L3: -AL-CO-O-AL-O-AL- L4: -AL-CO-O -AL-O-CO-L5: -CO-AR-O-AL-L6: -CO-AR-O-AL-O-L7: -CO-AR-O-AL-O-CO-L8: -CO -NH-AL-L9: -NH-AL-O-L10: -NH-AL-O-CO-L11: -O-AL-L12: -O-AL-O-L13: -O-AL-O- CO-

L14: -O-AL-O-CO-NH-AL-L15: -O-AL-S-AL-L16: -O-CO-AL-AR-O-AL-O-CO-L17: -O-CO-AR-O-AL-CO-L18: -O-CO-AR-O-AL-O-CO-L19: -O-CO-AR-O-AL-O-AL-OC
O-L20: -O-CO-AR-O-AL-O-AL-OA
L-O-CO-L21: -S-AL-L22: -S-AL-O-L23: -S-AL-O-CO-L24: -S-AL-S-AL-L25: -S-AR -AL-

In order to optically compensate for a liquid crystal cell in which rod-like liquid crystal molecules are twisted in the STN mode, it is preferable that the discotic liquid crystal molecules are also twisted. When an asymmetric carbon atom is introduced into the AL (alkylene group or alkenylene group), the discotic liquid crystal molecule can be twisted and aligned in a helical manner. Further, even when a compound (chiral agent) having an asymmetric carbon atom and exhibiting optical activity is added to the optically anisotropic layer, the discotic liquid crystal molecules can be twisted in a helical manner.

The polymerizable group (P) in the formula (I) is determined according to the type of the polymerization reaction. Examples of the polymerizable group (P) are shown below.

[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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The polymerizable group (P) is an unsaturated polymerizable group (P
1, P2, P3, P7, P8, P15, P16, P1
7) or an epoxy group (P6, P18), more preferably an unsaturated polymerizable group,
Ethylenically unsaturated polymerizable groups (P1, P7, P8, P1
5, P16, P17). In the formula (I), n is an integer of 4 to 12. Specific numbers are determined according to the type of discotic core (D). The combination of a plurality of L and P may be different, but is preferably the same.

Two or more discotic liquid crystal molecules may be used in combination. For example, the polymerizable discotic liquid crystal molecules and the non-polymerizable discotic liquid crystal molecules described above can be used in combination. The non-polymerizable discotic liquid crystal molecule is preferably a compound in which the polymerizable group (P) of the polymerizable discotic liquid crystal molecule is changed to a hydrogen atom or an alkyl group. That is, the non-polymerizable discotic liquid crystalline molecule is preferably a compound represented by the following formula (II). (II) D (-LR) _{n wherein} D is a discotic core; L is a divalent linking group; R is a hydrogen atom or an alkyl group;
Is an integer of 4 to 12. An example of the discotic core (D) of formula (II) is that LP (or PL) is replaced by LR (or R
Except for changing to L), it is the same as the example of the polymerizable discotic liquid crystal molecule described above. Further, a divalent linking group (L)
Is the same as the example of the polymerizable discotic liquid crystal molecule described above. The alkyl group represented by R has 1 to 4 carbon atoms.
It is preferably 0, more preferably 1 to 30. A chain alkyl group is more preferable than a cyclic alkyl group, and a straight-chain alkyl group is more preferable than a branched chain alkyl group. R is particularly preferably a hydrogen atom or a linear alkyl group having 1 to 30 carbon atoms.

The optically anisotropic layer is composed of discotic liquid crystal molecules or the following polymerizable initiators and optional additives (eg, plasticizers, monomers, surfactants, cellulose esters, 1,3,5- It is formed by applying a coating solution containing a triazine compound and a chiral agent) on the alignment film.
As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N,
N-dimethylformamide), sulfoxide (eg, dimethylsulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, chloroform, dichloromethane), ester (eg, methyl acetate, Butyl acetate), ketones (eg, acetone, methyl ethyl ketone), and ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The application of the coating solution can be performed by a known method (eg, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method).

The polymerization reaction of discotic liquid crystal molecules includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reactions are preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in U.S. Pat. Nos. 2,367,661 and 2,367,670) and acyloin ethers (U.S. Pat.
No. 8), α-hydrocarbon-substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (US Pat. Nos. 3,046,127 and 2,951)
758), a combination of a triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367), an acridine and phenazine compound (JP-A-60-105667, US Pat. No. 4,239,850). Oxadiazole compounds (described in US Pat. No. 4,221,970). The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight of the solid content of the coating solution.
Light irradiation for the polymerization of discotic liquid crystalline molecules
Preferably, ultraviolet light is used. The irradiation energy is 2
Is preferably 0 mJ / cm ² to 50 J / cm ^2, and more preferably in the range of 100 to 800 mJ / cm ^2. Light irradiation may be performed under heating conditions to promote the photopolymerization reaction. The thickness of the optically anisotropic layer is 0.1.
It is preferably 1 to 20 μm, and 0.5 to 15 μm.
μm, more preferably 1 to 10 μm.

Specifically, the alignment state of the discotic liquid crystal molecules in the optically anisotropic layer is determined by the type of liquid crystal molecules, the type of alignment film, and the additives (eg,
(A plasticizer, a binder, a surfactant). As the alignment state of the discotic liquid crystal molecules in the optically anisotropic layer, the average tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the polymer film is 5 to 85 °, and the discotic liquid crystal molecules When the distance between the molecule and the polymer film surface increases, the orientation of the discotic liquid crystal molecules is aligned so that the tilt angle between the disc surface and the plane of the polymer film increases (hybrid alignment).
It was normal to let them. However, the present inventor studied the splay alignment cell and found that the average tilt angle between the discotic liquid crystal molecules and the plane of the polymer film was 5 to 85 °, and that the discotic liquid crystal molecules and the polymer film surface were not aligned. When the distance between the discotic liquid crystal molecules and the plane of the polymer film becomes smaller, it is more suitable for the optical compensation of the liquid crystal cell. found.

In order to realize the above-mentioned reverse hybrid alignment, a vertical alignment film for discotic liquid crystal molecules described later is used, and a cellulose ester or a fluorine-containing surfactant is further added to the optically anisotropic layer. Is preferred. Furthermore, it is preferable to align the discotic liquid crystalline molecules while blowing hot air on the surface of the optically anisotropic layer opposite to the alignment film. The direction of the warm air is preferably parallel to the plane of the polymer film and parallel to the rubbing direction of the alignment film. Cellulose esters include lower fatty acid esters of cellulose and nitrocellulose. Preferred are lower fatty acid esters of cellulose. The “lower fatty acid” in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms.
The number of carbon atoms is preferably 2 to 5, more preferably 2 to 4. A substituent (eg, hydroxy) may be bonded to the fatty acid. Two or more fatty acids may form an ester with cellulose. Examples of lower fatty acid esters of cellulose include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose hydroxypropionate,
Includes cellulose acetate propionate and cellulose acetate butyrate. Cellulose acetate butyrate is particularly preferred. The butyrylation degree of cellulose acetate butyrate is preferably 30% or more, and more preferably 30 to 80%.
The acetylation degree of cellulose acetate butyrate is 3
It is preferably 0% or less, more preferably 1 to 30%. The cellulose ester is preferably used in an amount of 0.1 to 5% by weight based on the amount of the discotic liquid crystalline molecules.

The fluorinated surfactant comprises a hydrophobic group containing a fluorine atom, a nonionic, anionic, cationic or amphoteric hydrophilic group and an optional linking group. The fluorinated surfactant comprising one hydrophobic group and one hydrophilic group is represented by the following formula (III). (III) Rf-L ⁵ -Hy wherein, Rf is selected from the group consisting monovalent hydrocarbon radicals substituted with a fluorine atom, L ⁵ is a single bond or a divalent linking group,
Hy is a hydrophilic group. Rf in formula (III) functions as a hydrophobic group. The hydrocarbon group is preferably an alkyl group or an aryl group. The alkyl group preferably has 3 to 30 carbon atoms, and the aryl group preferably has 6 to 30 carbon atoms. Some or all of the hydrogen atoms contained in the hydrocarbon group are substituted with fluorine atoms. It is preferable to replace 50% or more of the hydrogen atoms contained in the hydrocarbon group with a fluorine atom, more preferably 60% or more, and 70% or more.
It is more preferable to replace the above, and it is most preferable to replace 80% or more. The remaining hydrogen atoms may be further substituted with another halogen atom (eg, chlorine atom, bromine atom). Examples of Rf are shown below.

[0060] _{Rf1: n-C 8 F 17} - Rf2: n-C 6 F 13 - Rf3: Cl- (CF 2 -CFCl) 3 -CF 2 - Rf4: H- (CF 2) 8 - Rf5: H- _{(CF 2) 10 - Rf6:} n-C 9 F 19 - Rf7: pentafluorophenyl _{Rf8: n-C 7 F 15} - Rf9: Cl- (CF 2 -CFCl) 2 -CF 2 - Rf10: H- (CF _{2) 4 - Rf11: H- (} CF 2) 6 - Rf12: Cl- (CF 2) 6 - Rf13: C 3 F 7 -

In the formula (III), the divalent linking group is an alkylene group, an arylene group, a divalent heterocyclic residue, -CO
—, —NR— (R is an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —SO ₂ — and a divalent linking group selected from the combination thereof. preferable. An example of a L ⁵ of the formula (III) below. The left side is bonded to a hydrophobic group (Rf), and the right side is a hydrophilic group (Hf).
y). AL represents an alkylene group, AR represents an arylene group, and Hc represents a divalent heterocyclic residue. In addition, the alkylene group, the arylene group, and the divalent heterocyclic residue may have a substituent (eg, an alkyl group).

[0062] L0: single bond _{L51: -SO 2 -NR- L52: -AL} -O- L53: -CO-NR- L54: -AR-O- L55: -SO 2 -NR-AL-CO-O- L56: -CO-O- L57: -SO 2 -NR-AL-O- L58: -SO 2 -NR-AL- L59: -CO-NR-AL- L60: -AL-O-AL- L61: - _{hc-AL- L62: -SO 2 -NR} -AL-O-AL- L63: -AR- L64: -O-AR-SO 2 -NR-AL- L65: -O-AR-SO 2 -NR- L66 : -O-AR-0-

Hy in the formula (III) is a nonionic hydrophilic group,
It is any of an anionic hydrophilic group, a cationic hydrophilic group, and an amphoteric hydrophilic group. Nonionic hydrophilic groups are particularly preferred. Examples of Hy in the formula (III) are shown below.

Hy1:-(CH ₂ CH ₂ O) _n -H (n
Is an integer of 5 to _{30) Hy2 :-( CH 2 CH 2} O) n -R 1 (n is 5 to 3
0 integer, R ¹ is an alkyl group having 1 to 6 carbon _{atoms) Hy3 :-( CH 2 CHOHCH 2)} n -H (n is 5 to 30 integer) Hy4: -COOM (M represents a hydrogen atom, an alkali metal atom or dissociated state) Hy5: -SO ₃ M (M is a hydrogen atom, an alkali metal atom or dissociated _{state) Hy6 :-( CH 2 CH 2 O} ) n -CH 2 CH 2 CH 2
-SO ₃ M (n is 5 to 30 integer, M is a hydrogen atom or an alkali metal _{atom) Hy7: -OPO (OH) 2} Hy8: -N + (CH 3) 3 · X - (X represents a halogen atom) Hy9 : -COONH ₄

A nonionic hydrophilic group (Hy1, Hy2, H
y3) is preferred, and a hydrophilic group (Hy1) composed of polyethylene oxide is most preferred. Specific examples of the fluorine-containing surfactant represented by the formula (III), shown with reference to examples of the above Rf, L ⁵ and Hy.

FS-1: Rf1-L51 (R = C ₃ H ₇ )
-Hy1 (n = 6) FS- 2: Rf1-L51 (R = C 3 H 7) -Hy1 (n
= 11) FS-3: Rf1 -L51 (R = C 3 H 7) -Hy1 (n
= 16) FS-4: Rf1 -L51 (R = C 3 H 7) -Hy1 (n
= 21) FS-5: Rf1 -L51 (R = C 2 H 7) -Hy1 (n
= 6) FS-6: Rf1 -L51 (R = C 2 H 7) -Hy1 (n
= 11) FS-7: Rf1 -L51 (R = C 2 H 7) -Hy1 (n
= 16) FS-8: Rf1 -L51 (R = C 2 H 7) -Hy1 (n
= 21) FS-9: Rf2 -L51 (R = C 3 H 7) -Hy1 (n
= 6) FS-10: Rf2 -L51 (R = C 3 H 7) -Hy1 (n
= 11) FS-11: Rf2 -L51 (R = C 3 H 7) -Hy1 (n
= 16) FS-12: Rf2 -L51 (R = C 3 H 7) -Hy1 (n
= 21) FS-13: Rf3 -L52 (AL = CH 2) -Hy1 (n
= 5) FS-14: Rf3 -L52 (AL = CH 2) -Hy1 (n
= 10) FS-15: Rf3 -L52 (AL = CH 2) -Hy1 (n
= 15) FS-16: Rf3 -L52 (AL = CH 2) -Hy1 (n
= 20) FS-17: Rf4 -L53 (R = C 3 H 7) -Hy1 (n
= 7) FS-18: Rf4 -L53 (R = C 3 H 7) -Hy1 (n
= 13) FS-19: Rf4 -L53 (R = C 3 H 7) -Hy1 (n
= 19) FS-20: Rf4 -L53 (R = C 3 H 7) -Hy1 (n
= 25)

FS-21: Rf5-L52 (AL = CH ₂ )
-Hy1 (n = 11) FS- 22: Rf5-L52 (AL = CH 2) -Hy1 (n
= 15) FS-23: Rf5 -L52 (AL = CH 2) -Hy1 (n
= 20) FS-24: Rf5 -L52 (AL = CH 2) -Hy1 (n
= 30) FS-25: Rf6-L54 (AR = p-phenylene)-Hy
1 (n = 11) FS-26: Rf6-L54 (AR = p-phenylene) -Hy
1 (n = 17) FS-27: Rf6-L54 (AR = p-phenylene) -Hy
1 (n = 23) FS-28: Rf6-L54 (AR = p-phenylene) -Hy
1 (n = 29) FS-29: Rf1-L55 (R = C ₃ H ₇ , AL = C
_{H 2) -Hy1 (n = 20} ) FS-30: Rf1-L55 (R = C 3 H 7, AL = C
_{H 2) -Hy1 (n = 30} ) FS-31: Rf1-L55 (R = C 3 H 7, AL = C
_{H 2) -Hy1 (n = 40} ) FS-32: Rf1-L56-Hy1 (n = 5) FS-33: Rf1-L56-Hy1 (n = 10) FS-34: Rf1-L56-Hy1 (n = 15) FS-35: Rf1-L56-Hy1 (n = 20) FS-36: Rf7-L56-Hy1 (n = 8) FS-37: Rf7-L56-Hy1 (n = 13) FS-38: Rf7- L56-Hy1 (n = 18) FS-39: Rf7-L56-Hy1 (n = 25)

FS-40: Rf1-L0-Hy1 (n =
6) FS-41: Rf1-L0-Hy1 (n = 11) FS-42: Rf1-L0-Hy1 (n = 16) FS-43: Rf1-L0-Hy1 (n = 21) FS-44: Rf1- _{L51 (R = C 3 H 7} ) -Hy2 (n
_{^{= 7, R 1 = C 2}} H 5) FS-45: Rf1-L51 (R = C 3 H 7) -Hy2 (n
_{^{= 13, R 1 = C 2}} H 5) FS-46: Rf1-L51 (R = C 3 H 7) -Hy2 (n
_{^{= 20, R 1 = C 2}} H 5) FS-47: Rf1-L51 (R = C 3 H 7) -Hy2 (n
_{^{= 28, R 1 = C 2}} H 5) FS-48: Rf8-L52 (AL = CH 2) -Hy1 (n
= 5) FS-49: Rf8 -L52 (AL = CH 2) -Hy1 (n
= 10) FS-50: Rf8 -L52 (AL = CH 2) -Hy1 (n
= 15) FS-51: Rf8 -L52 (AL = CH 2) -Hy1 (n
= 20) FS-52: Rf1-L57 (R = C ₃ H ₇ , AL = CH ₂ C
_{H 2) -Hy3 (n = 5} ) FS-53: Rf1-L57 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 7} ) FS-54: Rf1-L57 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 9} ) FS-55: Rf1-L57 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 12} ) FS-56: Rf9-L0-Hy4 (M = H) FS-57: Rf3-L0-Hy4 (M = H) FS-58: Rf1-L58 (R = C 3 H ₇ , AL = C
_{H 2) -Hy4 (M = K} ) FS-59: Rf4-L59 (R = C 3 H 7, AL = C
_{H 2) -Hy4 (M = Na} )

FS-60: Rf1-L0-Hy5 (M = K) FS-61: Rf10-L60 (AL ¹ = CH ₂ , AL ² = CH ₂ C)
_{H 2) -Hy5 (M = Na} ) FS-62: Rf11-L60 (AL 1 = CH 2, AL 2 = CH 2 C
_{H 2) -Hy5 (M = Na} ) FS-63: Rf5-L60 (AL 1 = CH 2, AL 2 = CH 2 C
_{H 2) -Hy5 (M = Na} ) FS-64: Rf1-L58 (R = C 3 H 7, AL = CH 2 CH 2 C
_{H 2) -Hy5 (M = Na} ) FS-65: Rf1-L51 (R = C 3 H 7) -Hy6 (n
= 5, M = Na) FS -66: Rf1-L51 (R = C 3 H 7) -Hy6 (n
= 10, M = Na) FS -67: Rf1-L51 (R = C 3 H 7) -Hy6 (n
= 15, M = Na) FS -68: Rf1-L51 (R = C 3 H 7) -Hy6 (n
= 20, M = Na) FS -69: Rf1-L58 (R = C 2 H 5, AL = CH 2
_{CH 2) -Hy7 FS-70:} Rf1-L58 (R = H, AL = CH 2 CH 2 CH 2)
-Hy8 (X = I) FS- 71: Rf11-L61 ( below _{Hc, AL = CH 2 CH 2} C
H ₂₎ -Hy6 (M dissociation)

[0070]

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FS-72: Rf1-L62 (R = C ₃ H ₇ , AL ¹ = CH ₂ C
^{_{H 2, AL 2 = CH 2}} CH 2 CH 2) -Hy6 (M = Na) FS-73: Rf12-L0-Hy5 (M = Na) FS-74: Rf13-L63 (AR = o- phenylene) -Hy
6 (M = K) FS-75: Rf13-L63 (AR = m-phenylene) -Hy
6 (M = K) FS-76: Rf13-L63 (AR = p-phenylene) -Hy
6 (M = K) FS- 77: Rf6-L64 (R = C 2 H 5, AL = CH 2 CH 2) -
Hy5 (M = H) FS-78: Rf6-L65 (AR = p-phenylene, R = C _{2
H 5) -Hy1 (n = 9} ) FS-79: Rf6-L65 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 14} ) FS-80: Rf6-L65 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 19} ) FS-81: Rf6-L65 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 28} ) FS-82: Rf6-L66 (AR = p- phenylene) -Hy
1 (n = 5) FS-83: Rf6-L66 (AR = p-phenylene) -Hy
1 (n = 10) FS-84: Rf6-L66 (AR = p-phenylene) -Hy
1 (n = 15) FS-85: Rf6-L66 (AR = p-phenylene) -Hy
1 (n = 20)

A fluorinated surfactant having two or more hydrophobic or hydrophilic groups containing a fluorine atom may be used. Examples of the fluorinated surfactant having two or more hydrophobic groups or hydrophilic groups are shown below.

[0073]

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FS-86: n1 + n2 = 12, FS-87: n1 + n2
= 18, FS-88: n1 + n2 = 24

[0075]

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FS-89: n1 + n2 = 20, FS-90: n1 + n2
= 18, FS-91: n1 + n2 = 40

[0077]

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FS-92: n = 5, FS-93: n = 10, F
S-94: n = 15, FS-95: n = 20

[0079]

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Two or more fluorine-containing surfactants may be used in combination. For fluorinated surfactants, see various references (eg, Hiroshi Horiguchi, “New Surfactants”, Sankyo Publishing (1975), MJ
Schick, Nonionic Surfactants, Marcell Dekker In
c., New York, (1967), JP-A-7-13293)
There is a description. The amount of the fluorinated surfactant is preferably in the range of 0.01 to 30% by weight, more preferably 0.1 to 10% by weight, more preferably 0.5 to 10% by weight, based on the amount of the discotic liquid crystal molecules. More preferably, the content is from 5 to 5% by weight.

[Vertical Alignment Film for Discotic Liquid Crystalline Molecules] In order to vertically align discotic liquid crystal molecules, it is important to lower the surface energy of the alignment film. Specifically, the surface energy of the alignment film is reduced by the functional group of the polymer, and thereby the discotic liquid crystal molecules are in a standing state. As the functional group that lowers the surface energy of the alignment film, a fluorine atom and a hydrocarbon group having 10 or more carbon atoms are effective. In order to make a fluorine atom or a hydrocarbon group exist on the surface of the alignment film, it is preferable to introduce a fluorine atom or a hydrocarbon group into a side chain rather than a main chain of the polymer. The fluorine-containing polymer preferably contains fluorine atoms at a ratio of 0.05 to 80% by weight, more preferably 0.1 to 70% by weight, and more preferably 0.5 to 65% by weight. More preferably, it is most preferably contained at a ratio of 1 to 60% by weight. The hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched, or linear. The aliphatic group is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The hydrocarbon group may have a substituent that does not show strong hydrophilicity, such as a halogen atom. The number of carbon atoms in the hydrocarbon group is preferably from 10 to 100, more preferably from 10 to 60, and most preferably from 10 to 40. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

The polyimide is generally synthesized by a condensation reaction between a tetracarboxylic acid and a diamine. A polyimide corresponding to a copolymer may be synthesized using two or more kinds of tetracarboxylic acids or two or more kinds of diamines. The fluorine atom or the hydrocarbon group may be present in a repeating unit derived from a tetracarboxylic acid, in a repeating unit derived from a diamine, or in both repeating units. When a hydrocarbon group is introduced into a polyimide, it is particularly preferable to form a steroid structure in the main chain or side chain of the polyimide. The steroid structure present in the side chain corresponds to a hydrocarbon group having 10 or more carbon atoms, and has a function of vertically aligning discotic liquid crystalline molecules. In the present specification, a steroid structure refers to a cyclopentanohydrophenanthrene ring structure or a ring structure in which a part of the bond of the ring is a double bond in the range of an aliphatic ring (range in which an aromatic ring is not formed). means.

Fluorine-modified polyvinyl alcohol can also be preferably used for the vertical alignment film. Fluorine-modified polyvinyl alcohol has 5 repeating units containing a fluorine atom.
In a range of 7 to 80 mol%, preferably 7 to 7 mol%.
More preferably, it is contained in the range of 0 mol%. Preferred fluorine-modified polyvinyl alcohol is represented by the following formula (PV). (PV)-(VAl) x- (FRU) y- (VAc) z- wherein VAl is a repeating unit of vinyl alcohol; FRU is a repeating unit containing a fluorine atom;
VAc is a vinyl acetate repeating unit; x is 20 to 95 mol% (preferably 24 to 90 mol%); y is 5 to 80 mol% (preferably 7 to 70 mol%); , Z are 0 to 30 mol% (preferably 2 to 20 mol%). A preferred repeating unit containing a fluorine atom (FRU) is represented by the following formula (FRU-I)
And (FRU-II).

[0084]

Embedded image

In the formula, L ¹ represents —O—, —CO—, —SO
₂ -, - NH-, an alkylene group, an arylene group and a divalent linking group selected from their combinations; L
² is a single bond or -O -, - CO -, - SO 2 -,
-NH-, a divalent linking group selected from an alkylene group, an arylene group and a combination thereof;
f ¹ and Rf ² are each a fluorine-substituted hydrocarbon group. The alkylene group and the arylene group may be substituted by a fluorine atom. Examples of the divalent linking group formed by the above combination are shown below.

[0086] L1: -O-CO- L2: -O -CO- alkylene group -O- L3: -O-CO- alkylene group -CO-NH- L4: -O-CO- alkylene group -NH-SO ₂ -Arylene group -O-L5: -arylene group -NH-CO-L6: -arylene group -CO-O-L7: -arylene group -CO-NH-L8: -arylene group -O-L9: -O-CO -NH-arylene group -NH-CO-

The hydrocarbon group of the fluorine-substituted hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched or linear. The aliphatic group is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The aliphatic group may have a substituent that does not show strong hydrophilicity, such as another halogen atom, in addition to the fluorine atom. The hydrocarbon group preferably has 1 to 100 carbon atoms,
It is more preferably from 60 to 60, and most preferably from 3 to 40. The proportion of the hydrogen atom of the hydrocarbon group substituted by a fluorine atom is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, and further preferably 80 to 100 mol%. It is most preferably 90 to 100 mol%.

Modified polyvinyl alcohol having a hydrocarbon group having 10 or more carbon atoms can also be preferably used for the vertical alignment film. The hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. Aliphatic groups are cyclic,
It may be either branched or linear. Aliphatic groups are
It is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The hydrocarbon group may have a substituent that does not show strong hydrophilicity, such as a halogen atom.
The number of carbon atoms in the hydrocarbon group is preferably from 10 to 100, more preferably from 10 to 60, and most preferably from 10 to 40. The modified polyvinyl alcohol having a hydrocarbon group contains 2 to 8 repeating units having a hydrocarbon group having 10 or more carbon atoms.
It is preferably contained in the range of 0 mol%, more preferably 3 to 70 mol%. Preferred number of carbon atoms is 1
The modified polyvinyl alcohol having 0 or more hydrocarbon groups is represented by the following formula (PV). (PV)-(VAl) x- (HyC) y- (VAc) z- wherein VAl is a repeating unit of vinyl alcohol; HyC is a repeating unit having a hydrocarbon group having 10 or more carbon atoms. VAc is a repeating unit of vinyl acetate; x is 20 to 95 mol% (preferably 2
Y is from 2 to 80 mol%)
(Preferably 3 to 70 mol%); and z is 0 to 30 mol% (preferably 2 to 20 mol%). Preferred repeating units (HyC) having a hydrocarbon group having 10 or more carbon atoms are represented by the following formulas (HyC-I) and (HyC-II).

[0089]

Embedded image

In the formula, L ¹ represents —O—, —CO—, —SO
₂ -, - NH-, an alkylene group, an arylene group and a divalent linking group selected from their combinations; L
² is a single bond or -O -, - CO -, - SO 2 -,
-NH-, a divalent linking group selected from an alkylene group, an arylene group and a combination thereof;
¹ and R ² are each a hydrocarbon group having 10 or more carbon atoms. Examples of the divalent linking group formed by the above-mentioned combination include the above-mentioned formulas (FRU-I) and (FRU-
-II).

The degree of polymerization of the polymer used for the vertical alignment film is as follows:
It is preferably from 200 to 5,000, more preferably from 300 to 3,000. The molecular weight of the polymer is
It is preferably from 9000 to 200,000, and 13
More preferably, it is 000 to 130,000.
Two or more polymers may be used in combination. In forming the vertical alignment film, it is preferable to perform a rubbing treatment. The rubbing treatment is performed by rubbing the surface of the film containing the polymer several times with paper or cloth in a certain direction. The rubbing direction is preferably antiparallel to the rubbing direction of the alignment film of the liquid crystal cell, as shown in FIG. The discotic liquid crystal molecules near the alignment film are vertically aligned using the vertical alignment film, and then the discotic liquid crystal molecules are fixed in the aligned state to form an optically anisotropic layer. Only the optically anisotropic layer may be transferred onto the polymer film. Discotic liquid crystal molecules fixed in an alignment state can maintain the alignment state without an alignment film. Therefore, in the optical compensation sheet, the vertical alignment film is not an essential element (although it is indispensable in manufacturing).

[0092]

[Example 1] (Preparation of splay alignment liquid crystal cell) A vertical alignment film (RN783, manufactured by Nissan Chemical Co., Ltd.) was provided on a glass substrate provided with an ITO transparent electrode, and a rubbing treatment was performed. Was. 10
Two substrates were stacked via a spacer of μm such that the alignment films faced each other. The orientation of the substrate was adjusted so that the rubbing directions of the alignment films were parallel. A rod-like nematic liquid crystalline molecule having negative dielectric anisotropy (MJ
95785, manufactured by Merck) by a vacuum injection method.
A liquid crystal layer was formed. The tilt angle of the rod-like liquid crystal molecules near the alignment film was 80 °. Δn of the liquid crystalline molecule is 0.081
3, and the value of Δnd of the liquid crystal layer was 813 nm.

(Preparation of Optical Compensation Sheet) Thickness 100 μm
(Fujitac, Fuji Photo Film Co., Ltd.) was provided with a 0.1 μm thick gelatin layer. The following modified polyvinyl alcohol solution was applied on the gelatin layer and dried with hot air at 80 ° C.
A rubbing treatment was performed to form an alignment film.

[0094]

Embedded image

A coating solution having the following composition was coated on the alignment film in # 1.
2 was applied using a wire bar coater, attached to a metal frame, and heated in a thermostat at 120 ° C. for 3 minutes to align the discotic liquid crystal compound.

<< Coating Liquid for Optically Anisotropic Layer >> ───────────────────────────────── The following discotic liquid crystalline compound 1.9 g Ethylene oxide modified trimethylolpropanetri Acrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g Cellulose acetate butyrate having a degree of acetylation of 2.0% and a degree of butyrylation of 52.0% (CAB-551-0.2, Eastman Chemical) 0.04 g Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.06 g Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02 g Methyl ethyl ketone 3.43 g ──────────────── ────────────

[0097]

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With the coating layer heated to 120 ° C.,
Ultraviolet rays were irradiated for 1 minute using a high-pressure mercury lamp of 0 W / cm to polymerize the terminal vinyl groups of the discotic liquid crystalline compound and fix the alignment state. Then, it was left to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet was produced. Examination of the orientation of the discotic liquid crystalline molecules in the optically anisotropic layer revealed that the average tilt angle between the discotic liquid crystalline molecules and the plane of the polymer film was 60 °, indicating that the discotic liquid crystalline molecules had an average tilt angle of 60 °. When the distance between the molecule and the surface of the polymer film is increased, the alignment (reverse hybrid alignment) is performed so that the inclination angle between the disc surface of the discotic liquid crystalline molecule and the plane of the polymer film becomes smaller. The thickness of the optically anisotropic layer is
It was 4.0 μm. When the retardation of the optical compensation sheet was measured with an ellipsometer (AEP-100, manufactured by Shimadzu Corporation), the Rth retardation value was 340 nm.

(Preparation of Polarizing Element) A polarizing film was prepared by adsorbing iodine on a stretched polyvinyl alcohol film. Using a polyvinyl alcohol-based adhesive, two 100 μm-thick triacetyl cellulose films (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) were attached to both sides of the polarizing film to produce a polarizing element.

(Preparation of Liquid Crystal Display Device) On both sides of the splay alignment liquid crystal cell, two optical compensatory sheets were attached so that the triacetyl cellulose film faced the cell substrate. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged in parallel. Two polarizing elements were attached to the outside of the optically anisotropic layer to produce a liquid crystal display. The directions of the polarization axes of the polarizing elements are orthogonal to each other,
The polarization axis and the rubbing direction of the liquid crystal cell were arranged at an angle of 45 °. 1 kHz in the liquid crystal cell of the liquid crystal display
By applying a rectangular wave voltage of z, a normally white mode of 2 V for white display and 6 V for black display was set. Using the ratio of the transmittance between the white display and the black display as the contrast ratio, the viewing angle at which a contrast ratio of 10 was obtained in the upper, lower, left, and right directions was measured. The results are shown in Table 1.

Example 2 (Preparation of Optical Compensation Sheet) N-methyl-2-pyrrolidone of the following modified polyimide was placed on a 100 μm-thick triacetyl cellulose film (Fujitac, manufactured by Fuji Photo Film Co., Ltd.). The solution was applied, dried at 80 ° C. for 5 minutes, and further heated at 180 ° C. for 60 minutes, and then subjected to a rubbing treatment to form an alignment film.

[0102]

Embedded image

A coating solution having the following composition was coated on the alignment film in # 8.
And heated for 10 minutes while blowing air at a speed of 10 m / s and a temperature of 130 ° C. in parallel with the surface of the support and also in the rubbing direction to align the discotic liquid crystal compound. .

<< Coating Liquid for Optically Anisotropic Layer >>デ ィ ス Discotic liquid crystalline compound used in Example 1 91 parts by weight Acetylation degree 0.5% by weight of cellulose acetate butyrate (CAB-551-0.2, manufactured by Eastman Chemical Co.) having a butyrylation degree of 52.0% 2.0% ethylene oxide-modified trimethylolpropane triacrylate (V # 360) 9 parts by weight Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by weight Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by weight 120 parts by weight methyl ethyl ketone ──────────────── ──────────────────

While the coating layer was heated to 130 ° C., it was irradiated with 600 mJ / cm ² ultraviolet rays using a high-pressure mercury lamp.
The terminal vinyl group of the discotic liquid crystalline compound was polymerized to fix the alignment state. Then, it was left to cool to room temperature.
Thus, an optically anisotropic layer was formed, and an optical compensation sheet was produced. Examination of the alignment state of the discotic liquid crystalline molecules in the optically anisotropic layer revealed that the average tilt angle between the disc surface of the discotic liquid crystalline molecules and the plane of the polymer film was 70 °, and that the discotic liquid crystalline When the distance between the molecule and the surface of the polymer film is increased, the orientation (reverse hybrid alignment) is such that the inclination angle between the disc surface of the discotic liquid crystalline molecule and the plane of the polymer film becomes smaller. When the Δnd of the optical compensation sheet was measured, it was 400 nm.

(Preparation of Liquid Crystal Display Device) On both sides of the splay alignment liquid crystal cell prepared in Example 1, two optical compensation sheets were attached so that the optically anisotropic layer faced the cell substrate. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged to be antiparallel. Two sheets of the polarizing element prepared in Example 1 were adhered to the outside of the optical compensation sheet to prepare a liquid crystal display device. The directions of the polarization axes of the polarizing elements were orthogonal to each other, and the polarization axis and the rubbing direction of the liquid crystal cell were arranged at an angle of 45 °. A 1 kHz rectangular wave voltage was applied to the liquid crystal cell of the liquid crystal display device to set a normally white mode of 2 V for white display and 6 V for black display. Using the ratio of the transmittance between the white display and the black display as the contrast ratio, the viewing angle at which a contrast ratio of 10 was obtained in the upper, lower, left, and right directions was measured. The results are shown in Table 1.

Example 3 (Preparation of Optical Compensation Sheet) A polystyrene film having a thickness of 60 μm was used as an optically anisotropic polymer film. The polystyrene film showed optically negative uniaxiality, and the optical axis was parallel to the film plane. Also,
The Re retardation of the film was 200 nm. As in Example 2, an alignment film was formed on a polystyrene film. The rubbing direction of the alignment film and the direction of the optical axis of the polystyrene film are parallel. A coating solution of the composition used in Example 2 was applied on the alignment film using a # 4 bar coater, and a wind at a speed of 10 m / s and a temperature of 130 ° C. was parallel to the surface of the support and parallel to the rubbing direction. And heated for 10 minutes to align the discotic liquid crystalline compound. While the coating layer was heated to 130 ° C., ultraviolet rays of 600 mJ / cm ² were irradiated using a high-pressure mercury lamp to polymerize the terminal vinyl groups of the discotic liquid crystal compound and fix the alignment state. Then, it was left to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet was produced. Examination of the orientation state of the discotic liquid crystalline molecules in the optically anisotropic layer revealed that the average tilt angle between the discotic liquid crystalline molecules and the plane of the polymer film was 50 °, and that the discotic liquid crystalline When the distance between the molecule and the surface of the polymer film is increased, the orientation (reverse hybrid alignment) is such that the inclination angle between the disc surface of the discotic liquid crystalline molecule and the plane of the polymer film becomes smaller. Δnd of optical compensation sheet
Was 200 nm.

(Preparation of Liquid Crystal Display) Two optical compensation sheets were adhered to both sides of the splay alignment liquid crystal cell prepared in Example 1 so that the optically anisotropic layer faced the cell substrate. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged to be antiparallel. Two sheets of the polarizing element prepared in Example 1 were adhered to the outside of the optical compensation sheet to prepare a liquid crystal display device. The directions of the polarization axes of the polarizing elements were orthogonal to each other, and the polarization axis and the rubbing direction of the liquid crystal cell were arranged at an angle of 45 °. A 1 kHz rectangular wave voltage was applied to the liquid crystal cell of the liquid crystal display device to set a normally white mode of 2 V for white display and 6 V for black display. Using the ratio of the transmittance between the white display and the black display as the contrast ratio, the viewing angle at which a contrast ratio of 10 was obtained in the upper, lower, left, and right directions was measured. The results are shown in Table 1.

Example 4 (Preparation of Optically Anisotropic Element) After a polycarbonate film having a thickness of 60 μm was uniaxially stretched, the film was stretched in the thickness direction of the film to prepare an optically anisotropic element. The Re retardation of the optically anisotropic element was 100 nm.
The Nz factor defined by the following equation was 0.5. Nz = (nx−nz) / (nx−ny) where nx and ny are in-plane principal refractive indices (nx
>Ny); nz is the refractive index in the thickness direction; and
d is the thickness.

(Preparation of Liquid Crystal Display Device) On both sides of the splay alignment liquid crystal cell prepared in Example 1, two optical compensation sheets prepared in Example 3 were placed so that the optically anisotropic layer faces the cell substrate. Pasted on. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged to be antiparallel. One sheet of the optically anisotropic element produced as described above was attached to one outside of the optical compensation sheet. The arrangement was such that the angle between the rubbing direction of the liquid crystal cell and the nx direction of the optically anisotropic element was 45 °. A liquid crystal display device was manufactured by attaching two polarizing elements manufactured in Example 1 to the outside of the optically anisotropic element. The directions of the polarization axes of the polarizing elements were orthogonal to each other, and the polarization axis and the rubbing direction of the liquid crystal cell were arranged at an angle of 45 °. A 1 kHz rectangular wave voltage is applied to the liquid crystal cell of the liquid crystal display device, and a white display 2
V, black display 6 V, normally white mode. The ratio of the transmittance between the white display and the black display is defined as the contrast ratio,
The viewing angle at which a contrast ratio of 10 was obtained in the upper, lower, left and right directions was measured. The results are shown in Table 1.

Example 5 (Production of Optically Anisotropic Element) A 100 μm thick polystyrene film was used as an optically anisotropic polymer film. The polystyrene film showed optically negative uniaxiality, and the optical axis was parallel to the film plane. The Re retardation of the film measured with light having a wavelength of 550 nm was 200 nm. As in Example 2, an alignment film was formed on a polystyrene film. The rubbing direction of the alignment film and the direction of the optical axis of the polystyrene film are parallel. A coating solution having the composition used in Example 2 was applied on the alignment film using a # 3 bar coater,
Heating was performed for 10 minutes while blowing air at a speed of 10 m / s and a temperature of 130 ° C. in parallel with the surface of the support and in parallel with the rubbing direction, thereby aligning the discotic liquid crystalline compound. While the coating layer was heated to 130 ° C., ultraviolet rays of 600 mJ / cm ² were irradiated using a high-pressure mercury lamp to polymerize the terminal vinyl groups of the discotic liquid crystal compound and fix the alignment state. Then, it was left to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet was produced. Examination of the orientation state of the discotic liquid crystalline molecules in the optically anisotropic layer revealed that the average tilt angle between the discotic liquid crystalline molecules and the plane of the polymer film was 50 °, and that the discotic liquid crystalline When the distance between the molecule and the surface of the polymer film is increased, the orientation (reverse hybrid alignment) is such that the inclination angle between the disc surface of the discotic liquid crystalline molecule and the plane of the polymer film becomes smaller. When the Δnd of the optically anisotropic element was measured, it was 160 nm.

(Preparation of Elliptical Polarizing Plate) Iodine was adsorbed on a stretched polyvinyl alcohol film to prepare a polarizing film. The above-mentioned optical compensation sheet was bonded to one side of the polarizing film using a polyvinyl alcohol-based adhesive so that the optically anisotropic layer was on the outside. The angle between the polarization axis of the polarizing film and the rubbing direction of the optical compensation sheet was set to 45 °. On the other side of the polarizing film, a thickness of 10
A 0 μm triacetyl cellulose film (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) was adhered to produce an elliptically polarizing plate.

(Preparation of Liquid Crystal Display) On the both sides of the splay alignment liquid crystal cell prepared in Example 1, the above-mentioned elliptically polarizing plate was formed using an acrylic adhesive, and the optically anisotropic layer was opposed to the liquid crystal cell. To form a liquid crystal display device. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged to be antiparallel. A 1 kHz rectangular wave voltage was applied to the liquid crystal cell of the liquid crystal display device to set a normally white mode of 2 V for white display and 6 V for black display. Using the ratio of the transmittance between the white display and the black display as the contrast ratio, the viewing angle at which a contrast ratio of 10 was obtained in the upper, lower, left, and right directions was measured. The results are shown in Table 1.

[0114]

[Table 1] Table 1 視野 Sample viewing angle number Upper lower Left Right ──────────────────────────────────── Example 1 70 ゜ 71 ゜ 76 ゜ 76 ゜ Example 2 72 ゜ 73 ゜ 76 ゜ 76 ゜ Example 3 75 ゜ 76 ゜ 80 ゜ 80 ゜ Example 4 81 ゜ 82 ゜ 80 ゜ 80 ゜ Example 5 70 ゜ 70 ゜ 75 ゜ 75 ゜────────────────────────────

Example 6 (Production of ECB liquid crystal cell) A polyimide alignment film was provided on a glass substrate provided with an ITO transparent electrode, and rubbing treatment was performed. Two substrates were stacked via a 3 μm spacer so that the alignment films faced each other. The orientation of the substrate was adjusted so that the rubbing direction of the alignment film was antiparallel.
A rod-like liquid crystal molecule (ZLI1565, manufactured by Merck) was injected into the gap between the substrates to form a liquid crystal layer. Δ of liquid crystalline molecules
n was 0.1297.

(Preparation of Optical Compensation Sheet) A polystyrene film having a thickness of 60 μm was used as an optically anisotropic polymer film. The polystyrene film showed optically negative uniaxiality, and the optical axis was parallel to the film plane. The Re retardation of the film is 100
nm. A gelatin subbing layer was provided on the polystyrene film so that the dry film thickness was 0.1 μm.
A solution of the modified polyvinyl alcohol used in Example 1 was applied on the gelatin undercoat layer,
After drying with warm air of ° C., a rubbing treatment was performed to form an alignment film. The rubbing direction of the alignment film and the direction of the optical axis of the polystyrene film are parallel. A coating solution having the following composition is applied on the alignment film using a # 3 wire bar coater, attached to a metal frame, and heated in a thermostat at 120 ° C. for 3 minutes to obtain a discotic liquid crystalline compound. Was oriented.

<< Coating Liquid for Optically Anisotropic Layer >>デ ィ ス Discotic liquid crystalline compound used in Example 1 1.8 g Fluorine-containing interface Activator (FS-3) 0.02 g Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.06 g Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02 g Methyl ethyl ketone 3.43 g ────────

While the coating layer was heated to 120 ° C., 12
Ultraviolet rays were irradiated for 1 minute using a high-pressure mercury lamp of 0 W / cm to polymerize the terminal vinyl groups of the discotic liquid crystalline compound and fix the alignment state. Then, it was left to cool to room temperature. Thus, the optically anisotropic layer (thickness: 1.0 μm)
m) to form an optical compensation sheet. When the alignment state of the discotic liquid crystal molecules in the optically anisotropic layer was examined, the average tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the polymer film was 70 °.
When the Δnd of the optical compensation sheet was measured, it was 80 nm.

(Preparation of Liquid Crystal Display Device) On both sides of the ECB liquid crystal cell, two optical compensation sheets were attached so that the polystyrene film faced the cell substrate. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged so as to be parallel. Two polarizing elements prepared in Example 1 were attached to the outside of the optically anisotropic layer to prepare a liquid crystal display device. The directions of the polarization axes of the polarizing elements were orthogonal to each other, and the polarization axis and the rubbing direction of the liquid crystal cell were arranged at an angle of 45 °. A voltage was applied to the liquid crystal cell of the liquid crystal display device, and the viewing angle at which a contrast ratio of 10 was obtained in the vertical and horizontal directions was measured using the ratio of the transmittance between white display and black display as the contrast ratio. As a result, the total viewing angle above and below is 1
The total viewing angle on the left and right was 140 °.

[Example 7] (Production of TN liquid crystal cell) A polyimide alignment film was provided on a glass substrate provided with an ITO transparent electrode, and rubbing treatment was performed. Two substrates were stacked via a 5 μm spacer so that the alignment films faced each other. The orientation of the substrate was adjusted so that the rubbing directions of the alignment films were orthogonal. In the gap between the substrates, rod-like liquid crystal molecules (ZL4792, manufactured by Merck)
Was injected to form a liquid crystal layer. Δn of the liquid crystalline molecule is 0.
0969.

(Preparation of Optical Compensation Sheet) A polystyrene film having a thickness of 60 μm was used as an optically anisotropic polymer film. The polystyrene film showed optically negative uniaxiality, and the optical axis was parallel to the film plane. The Re retardation of the film is 100
nm. A gelatin subbing layer was provided on the polystyrene film so that the dry film thickness was 0.1 μm.
A solution of the modified polyvinyl alcohol used in Example 1 was applied on the gelatin undercoat layer,
After drying with warm air of ° C., a rubbing treatment was performed to form an alignment film. The rubbing direction of the alignment film and the direction of the optical axis of the polystyrene film are parallel. A coating solution having the following composition was applied on the alignment film using a # 3 bar coater, and heated at 120 ° C. for 10 minutes to align the discotic liquid crystalline compound.

<< Coating Liquid for Optically Anisotropic Layer >>デ ィ ス 91 parts by weight of the discotic liquid crystal compound used in Example 1 Tick liquid crystal compound (2) 1.6 parts by weight Fluorine-containing surfactant (FS-3) 1.0 part by weight Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9 Parts by weight Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by weight Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by weight 120 parts by weight methyl ethyl ketone ─────────────────────────

[0123]

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While the coating layer was heated to 130 ° C., it was irradiated with 600 mJ / cm ² ultraviolet rays using a high-pressure mercury lamp.
The terminal vinyl group of the discotic liquid crystalline compound was polymerized to fix the alignment state. Then, it was left to cool to room temperature.
Thus, an optically anisotropic layer was formed, and an optical compensation sheet was produced. When the alignment state of the discotic liquid crystal molecules in the optically anisotropic layer was examined, the average tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the polymer film was 70 °. When the Δnd of the optical compensation sheet was measured, it was 120 nm. In addition, the discotic liquid crystal molecules were oriented by being twisted by 45 °.

(Preparation of Elliptical Polarizing Plate) Iodine was adsorbed to a stretched polyvinyl alcohol film to prepare a polarizing film. The above-mentioned optical compensation sheet was bonded to one side of the polarizing film using a polyvinyl alcohol-based adhesive so that the optically anisotropic layer was on the outside. The polarization axis of the polarizing film and the optical axis of the polystyrene film were arranged so as to be parallel. An elliptically polarizing plate was prepared by laminating a 100 μm thick triacetyl cellulose film (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) to the other side of the polarizing film.

(Preparation of Liquid Crystal Display Device) Two elliptically polarizing plates were attached to both sides of the TN liquid crystal cell using an acrylic adhesive so that the optically anisotropic layer was on the liquid crystal cell side.
A liquid crystal display device was created. The optical axis of the polystyrene film and the rubbing direction of the liquid crystal cell were arranged in parallel. A voltage is applied to the liquid crystal cell of the liquid crystal display device, and a ratio of transmittance between white display and black display is defined as a contrast ratio.
The viewing angle at which a contrast ratio of 10 was obtained in the vertical and horizontal directions was measured. As a result, the upper and lower total viewing angles were 110 ° and the left and right total viewing angles were 140 °.

Example 8 (Production of HAN liquid crystal cell) A glass substrate provided with an ITO transparent electrode and a glass substrate provided with a reflective electrode by aluminum evaporation were produced. On a glass substrate provided with ITO transparent electrodes, a vertical alignment film (RN783, Nissan Chemical Co., Ltd.)
Manufactured). A polyimide horizontal alignment film was provided on a glass substrate provided with an aluminum reflective electrode, and rubbing treatment was performed. Two substrates were overlapped via a 5 μm spacer so that the alignment films faced each other, and sealed with a sealing material. Rod-like nematic liquid crystal molecules having negative dielectric anisotropy (MJ95785, manufactured by Merck) were injected into the gap between the substrates by a vacuum injection method to form a liquid crystal layer. The Δn of the liquid crystal molecule is 0.0813, and the Δnd of the liquid crystal layer
Was 407 nm.

(Preparation of Liquid Crystal Display) On the substrate provided with the transparent electrode of the HAN liquid crystal cell, the optical compensation sheet prepared in Example 5 was placed so that the optically anisotropic layer faces the substrate of the liquid crystal cell. With an acrylic adhesive. The rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer were arranged so as to be parallel. On the outside of the optical compensation sheet, λ
A liquid crystal display device was prepared by attaching a ／ plate and further attaching the polarizing element prepared in Example 1 to the outside thereof. λ
The direction of the slow axis of the ４ plate and the direction of the polarizing axis of the polarizing element were arranged at an angle of 45 °. A voltage was applied to the liquid crystal cell of the liquid crystal display device, and the viewing angle at which a contrast ratio of 10 was obtained in the vertical and horizontal directions was measured using the ratio of the transmittance between white display and black display as the contrast ratio. As a result, the upper and lower total viewing angles were 70 ° and the left and right total viewing angles were 80 °.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing the orientation of a liquid crystalline compound in a splay alignment liquid crystal cell.

FIG. 2 is a schematic diagram of a liquid crystal display device using a splay alignment liquid crystal cell.

FIG. 3 is a conceptual diagram showing optical compensation of a splay alignment liquid crystal cell by an optical compensation sheet.

FIG. 4 is a cross-sectional view schematically showing the orientation of a liquid crystal compound in a HAN mode liquid crystal cell.

FIG. 5 is a schematic diagram of a liquid crystal display device using a HAN mode liquid crystal cell.

FIG. 6 is a conceptual diagram showing optical compensation of a HAN mode liquid crystal cell by an optical compensation sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Liquid crystal layer 1a-1h Rod-like liquid crystalline molecule 2a Lower alignment film 2b Upper alignment film 3a Lower transparent electrode 3b Upper transparent electrode 4a Lower substrate 4b Upper substrate 10 Liquid crystal cell 11 Polarizing element 11a Lower polarizing element 11b Upper polarizing element 12, 12a, 12b Optical compensation sheet or optically anisotropic layer 13 Transparent support BL Backlight PAa Direction of polarization axis of lower polarizing element PAb Direction of polarization axis of upper polarizing element RDa, RDb Rubbing direction of alignment film of liquid crystal cell RDc, RDd Rubbing direction of optically anisotropic element RP Reflector XX Intermediate (symmetrical plane) between two alignment films

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H049 BA02 BA04 BA06 BA26 BA42 BB03 BB33 BB43 BB47 BB49 BC02 BC04 BC22 2H091 FA07X FA07Z FA11X FA11Z FB02 FD06 GA01 GA06 GA16 LA17 LA19 4F071 AA01 AA19 AG12 AA19 AG AH19 BA02 BB02 BC01 4F100 AG00 AJ06B AJ09 AK12A AK21 AS00B BA02 BA04 BA10B BA10C BA22 CA18B EH46 GB41 JA20B JN01A JN01C JN10D JN30B YY00B

Claims (13)

[Claims] 1. An optical compensatory sheet having an optically anisotropic layer formed from discotic liquid crystal molecules on a transparent support, wherein the transparent support substantially has an optical negative uniaxial property. An optical compensatory sheet having an optical axis substantially parallel to the plane of the transparent support. 2. The optical compensation sheet according to claim 1, wherein the transparent support comprises a polystyrene film. 3. The discotic liquid crystal molecules and the transparent support having an average inclination angle of 5 to 85 ° between the disk surface of the discotic liquid crystal molecules and the plane of the transparent support in the optically anisotropic layer. 2. The optical compensatory sheet according to claim 1, wherein the discotic liquid crystal molecules are oriented such that as the distance from the surface increases, the inclination angle between the disc surface of the discotic liquid crystal molecules and the plane of the transparent support decreases. . 4. An elliptically polarizing plate in which a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer formed from discotic liquid crystalline molecules are laminated in this order,
An elliptically polarizing plate, wherein the transparent support has substantially optical negative uniaxiality, and the optical axis is substantially parallel to the support plane. 5. The elliptically polarizing plate according to claim 4, wherein the angle between the optical axis of the transparent support and the polarization axis of the polarizing film is substantially 45 °. 6. A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, a pair of polarizing elements disposed on both sides thereof, and a liquid crystal cell disposed between the liquid crystal cell and both or one of the polarizing elements. A transmission type liquid crystal display device comprising an optical compensatory sheet, wherein the average tilt angle between the major axis direction of the rod-like liquid crystal molecules of the liquid crystal cell and the substrate surface in black display is less than 50 °,
The optical compensation sheet has, in order from the outside, a transparent support and an optically anisotropic layer formed from discotic liquid crystalline molecules laminated thereon, and the transparent support substantially reduces optical negative uniaxiality. A liquid crystal display device having an optical axis substantially parallel to the plane of the transparent support. 7. A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, an optical compensation sheet, and a polarizing element are laminated in this order. A reflective liquid crystal display device in which the average tilt angle between the major axis direction and the substrate surface is less than 50 °, wherein the optical compensation sheet is formed from a transparent support and discotic liquid crystalline molecules in order from the polarizing element side. An optically anisotropic layer is laminated thereon, and the transparent support has substantially optical negative uniaxiality, and its optical axis is substantially parallel to the plane of the transparent support. A liquid crystal display device characterized by the above-mentioned. 8. An optical compensatory sheet having an optically anisotropic layer formed from discotic liquid crystalline molecules on a transparent support, wherein the discotic surface of the discotic liquid crystalline molecules in the optically anisotropic layer is provided. When the average inclination angle between the transparent support and the plane of the transparent support is 5 to 85 °, and the distance between the discotic liquid crystal molecules and the surface of the transparent support becomes large, the disc surface of the discotic liquid crystal molecules and the transparent support become An optical compensation sheet, wherein discotic liquid crystal molecules are oriented so that the inclination angle with respect to a plane is small. 9. The optically anisotropic layer may further comprise a cellulose ester in an amount in the range of 0.1 to 5% by weight based on the amount of the discotic liquid crystal molecules, or a fluorinated surfactant added to the discotic liquid crystal molecules. 0.01 to 30% by weight of the amount
The optical compensatory sheet according to claim 8, wherein the optical compensatory sheet is contained in an amount in the range of: 10. An elliptically polarizing plate in which a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer formed of discotic liquid crystalline molecules are laminated in this order, The average tilt angle between the disk surface of the discotic liquid crystalline molecules in the transparent layer and the plane of the transparent support is 5 to 85.
゜, when the distance between the discotic liquid crystal molecules and the surface of the transparent support increases, the discotic liquid crystal molecules are adjusted so that the inclination angle between the discotic liquid crystal molecules and the plane of the transparent support decreases. An elliptically polarizing plate, characterized in that is oriented. 11. The angle between the average direction of a line obtained by projecting the normal of the discotic liquid crystalline molecule on the plane of the transparent support and the polarization axis of the polarizing film is substantially 45 °. The elliptically polarizing plate according to 1. 12. A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, a pair of polarizing elements disposed on both sides of the liquid crystal cell, and disposed between the liquid crystal cell and both or one of the polarizing elements. A liquid crystal cell, wherein the average tilt angle between the major axis direction of the rod-shaped liquid crystal molecules of the liquid crystal cell and the substrate surface in a black display is less than 50 °, wherein the optical compensation sheet is The transparent support and the optically anisotropic layer formed of discotic liquid crystalline molecules are laminated in this order, and the disk surface of the discotic liquid crystalline molecules in the optically anisotropic layer and the flat surface of the transparent support. Is 5 to 85 °, and when the distance between the discotic liquid crystal molecules and the surface of the transparent support increases, the tilt angle between the disc surface of the discotic liquid crystal molecules and the plane of the transparent support increases. Small Liquid crystal display device wherein the discotic liquid crystal molecules are aligned as described above. 13. A liquid crystal cell in which rod-like liquid crystal molecules are sealed in a gap between two substrates, an optical compensation sheet, and a polarizing element are laminated in this order. A reflective liquid crystal display device in which the average tilt angle between the major axis direction and the substrate surface is less than 50 °, wherein the optical compensation sheet is formed from a transparent support and discotic liquid crystalline molecules in order from the polarizing element side. An optically anisotropic layer is laminated, and the average tilt angle between the discotic liquid crystal molecules in the optically anisotropic layer and the plane of the transparent support is 5 to 85 °, When the distance between the liquid crystal molecules and the surface of the transparent support increases, the discotic liquid crystal molecules must be oriented so that the inclination angle between the discotic liquid crystal molecules and the plane of the transparent support decreases. A liquid crystal display device characterized by the following.