JP2001330725A - Optical compensation sheet, elliptically polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an inclined angle of discotic liquid crystalline molecules in an optically anisotropic layer formed of the discotic liquid crystalline molecules of which the inclined angle varies in accordance with the distance from a transparent supporting body surface. SOLUTION: In the optical compensation sheet having the optically anisotropic layer formed of the discotic liquid crystalline molecules and the transparent supporting body, the discotic liquid crystalline molecules are aligned so as to make the inclined angle of the discotic liquid crystalline molecules vary in accordance with the distance between the discotic liquid crystalline molecules and the transparent supporting body surface. Furthermore, a fluorine compound having a fluorine substituted alkyl group and a hydrophilic group is added to the optically anisotropic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical compensation sheet, an elliptically polarizing plate, and a liquid crystal display.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal cell, a polarizing element and an optical compensation sheet (a retardation plate). In a transmission type liquid crystal display device, two polarizing elements are attached to both sides of a liquid crystal cell, and one or two optical compensation sheets are arranged between the liquid crystal cell and the polarizing element. In a reflection type liquid crystal display device, a reflection plate, a liquid crystal cell, one optical compensation sheet, and one polarizing element are arranged in this order. The liquid crystal cell is composed of rod-like liquid crystal molecules, two substrates for enclosing the same, and an electrode layer for applying a voltage to the rod-like liquid crystal molecules. In the liquid crystal cell, the alignment state of the rod-like liquid crystal molecules is different. For the transmission type, TN (Twisted Nematic) and IPS (In-Plane Sw) are used.
itching), FLC (Ferroelectric Liquid Crysta)
l), OCB (Optically Compensatory Bend), STN
(Supper Twisted Nematic), VA (Vertically Align)
ed) and TN, HAN (Hybrid Align)
Various display modes such as ed Nematic) GH (Guest-Host) have been proposed.

[0003] Optical compensatory sheets are used in various liquid crystal display devices in order to eliminate coloring of images and to increase the viewing angle. As the optical compensation sheet, a stretched birefringent film has been conventionally used. It has been proposed to use an optical compensatory sheet having an optically anisotropic layer formed of discotic liquid crystalline molecules on a transparent support instead of the optical compensatory sheet made of a stretched birefringent film. The optically anisotropic layer is formed by applying a discotic liquid crystal composition containing discotic liquid crystal molecules on the alignment film,
The discotic liquid crystal molecules are formed by heating at a temperature higher than the alignment temperature. Generally, discotic liquid crystalline molecules have a large birefringence. And
Discotic liquid crystalline molecules have various alignment forms. By using discotic liquid crystal molecules, it has become possible to realize optical properties that cannot be obtained with a conventional stretched birefringent film.

[0004] The optical properties of the optical compensatory sheet are determined according to the optical properties of the liquid crystal cell, specifically, the above-mentioned difference in display mode. When discotic liquid crystal molecules are used, an optical compensatory sheet having various optical properties corresponding to various display modes of a liquid crystal cell can be manufactured. As optical compensation sheets using discotic liquid crystal molecules, ones corresponding to various display modes have already been proposed. For example, an optical compensatory sheet for a TN mode liquid crystal cell is disclosed in JP-A-6-214116, US Pat.
No. 5,83,679 and 5,646,703 and German Patent Publication 391620A1. Also,
The IPS mode or FLC mode optical compensation sheet for a liquid crystal cell is described in JP-A-10-54982. Further, an optical compensatory sheet for an OCB mode or HAN mode liquid crystal cell is described in US Pat. No. 5,805,253 and International Patent Application WO 96/37804. Further, an optical compensatory sheet for a liquid crystal cell in the STN mode is described in JP-A-9-26572. An optical compensation sheet for a VA mode liquid crystal cell is described in Japanese Patent No. 2866372.

[0005]

Problems to be Solved by the Invention
No. 6, U.S. Pat. Nos. 5,583,679 and 564,670.
No. 3, German Patent Publication No. 391620A1 discloses an optical compensation sheet for a TN mode liquid crystal cell comprising a discotic liquid crystal molecule in which an optically anisotropic layer is oriented at an average tilt angle of 5 to 50 degrees. Has formed. further,
The discotic liquid crystal molecules are oriented so that the tilt angle of the discotic liquid crystal molecules changes with the distance between the discotic liquid crystal molecules and the surface of the transparent support. However, when the present inventor studied a conventional optical compensation sheet, light leakage from an oblique direction of the polarizing plate was observed,
The viewing angle has not expanded sufficiently (to the extent theoretically expected). As a result of further studies by the present inventors, it has been found that the above problem can be solved by increasing the tilt angle of the discotic liquid crystalline molecules contained in the optically anisotropic layer. However, it is very difficult to arbitrarily adjust the change in the tilt angle of the discotic liquid crystal molecules in the optically anisotropic layer, and it has been practically impossible with the conventional technology.

[0006] Recently, discotic liquid crystal molecules having a molecular structure in which a side chain containing a benzene ring and a double bond conjugated to the benzene ring are bonded to a discotic nucleus have a high intrinsic birefringence and an optical birefringence. It turned out that it is preferably used for a compensation sheet. However, when discotic liquid crystal molecules having a high intrinsic birefringence are used, the problem that the tilt angle of the discotic liquid crystal molecules is insufficient becomes more remarkable than before. An object of the present invention is to increase the tilt angle of discotic liquid crystal molecules in an optically anisotropic layer formed from discotic liquid crystal molecules in which the tilt angle changes with the distance to the transparent support surface. It is. Still another object of the present invention is to provide an optical compensatory sheet capable of accurately and optically compensating a TN mode liquid crystal cell.

[0007]

An object of the present invention is to provide an optical compensatory sheet of the following (1) to (5), a liquid crystal display of the following (6) and (8) and an elliptically polarizing plate of the following (7). Achieved. (1) An optical compensation sheet having an optically anisotropic layer formed of discotic liquid crystal molecules and a transparent support, wherein the tilt angle of the discotic liquid crystal molecules is between the discotic liquid crystal molecules and the surface of the transparent support. Wherein the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. (2) The optically anisotropic layer contains 1 to 35 mg of a fluorine compound.
The optical compensatory sheet according to (1), wherein the optical compensatory sheet is contained in an amount of / m ² . (3) The optical compensation sheet according to (1), wherein the fluorine compound is a fluorine-containing surfactant. (4) The optical compensation sheet according to (1), wherein the fluorine compound is a copolymer comprising a repeating unit having a fluorine-substituted alkyl group in a side chain and a repeating unit having a hydrophilic group in a side chain. (5) The optical compensation sheet according to (1), wherein the discotic liquid crystal molecule has a molecular structure in which a side chain containing a benzene ring and a double bond conjugated thereto is bonded to a discotic nucleus.

(6) A transmission type liquid crystal display device comprising a TN mode liquid crystal cell and two polarizing plates disposed on both sides thereof, wherein a discotic liquid crystal is provided between at least one of the polarizing plates and the liquid crystal cell. Compensation sheet with an optically anisotropic layer formed of conductive molecules and a transparent support is arranged, and the tilt angle of the discotic liquid crystalline molecules changes with the distance between the discotic liquid crystalline molecules and the transparent support surface The liquid crystal display device, wherein the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. (7) An elliptically polarizing plate in which an optically anisotropic layer formed from discotic liquid crystal molecules, a transparent support, a polarizing film and a transparent protective film are laminated in this order, and the tilt angle of the discotic liquid crystal molecules Has changed with the distance between the discotic liquid crystal molecules and the transparent support surface, and the optically anisotropic layer further comprises a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. Elliptical polarizing plate. (8) A transmission type liquid crystal display device comprising a TN mode liquid crystal cell and two polarizing plates disposed on both sides thereof,
At least one of the polarizing plates is an elliptically polarizing plate in which an optically anisotropic layer formed from discotic liquid crystal molecules, a transparent support, a polarizing film and a transparent protective film are laminated in this order, and the discotic liquid crystal molecules are Is changed with the distance between the discotic liquid crystal molecules and the transparent support surface, and the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. Characteristic liquid crystal display device. The tilt angle of the discotic liquid crystal molecules means the angle between the disc surface of the discotic liquid crystal molecules and the plane of the transparent support.

[0009]

As a result of the research, the present inventors have found that by adding a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group to an optically anisotropic layer, the tilt angle of discotic liquid crystal molecules can be increased. Succeeded. Fluorine compounds
It has the effect of increasing the tilt angle of discotic liquid crystalline molecules. Therefore, it has become possible to arbitrarily adjust the tilt angle of the discotic liquid crystal molecules by adding a fluorine compound (adjusting the addition amount as necessary). In order to accurately and optically compensate the TN mode liquid crystal cell, it is desirable to increase the tilt angle of the discotic liquid crystal molecules as compared with the conventional optical compensation sheet. According to the present invention, the tilt angle of the discotic liquid crystal molecules can be increased, so that an optical compensation sheet accurately corresponding to a TN mode liquid crystal cell can be obtained. By using such an optical compensatory sheet, light leakage from the oblique direction of the polarizing plate can be prevented, and the viewing angle of the liquid crystal display device can be sufficiently (more than ever) increased.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [Optical Anisotropic Layer] The optically anisotropic layer is formed from discotic liquid crystal molecules. The tilt angle of the discotic liquid crystal molecules changes with the distance between the discotic liquid crystal molecules and the surface of the transparent support. The specific alignment state of the discotic liquid crystal molecules is determined according to the type of display mode of the liquid crystal cell. The alignment state of the liquid crystal molecules depends on the type of discotic liquid crystal molecules, the type of alignment film, the fluorine compound described below, and other additives (eg, plasticizer, binder, surfactant) in the optically anisotropic layer. Controlled by use.

Discotic liquid crystalline molecules are described in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., V
ol. 71, page 111 (1981); edited by The Chemical Society of Japan, quarterly chemistry review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2
(1994); B. Kohne et al., Angew. Chem. Soc. Chem. C
omm., page 1794 (1985); J. Zhang et al., J. Am. Che
m. Soc., vol. 116, page 2655 (1994)). Regarding the polymerization of discotic liquid crystalline molecules,
It 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 an oriented 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 (-LQ) _{n wherein} D is a discotic core; L is a divalent linking group; Q is a polymerizable group; and n is 4 to 12 Is an integer. An example of the discotic core (D) of the above formula is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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In the above formula, the divalent linking group (L) is
Alkylene group, alkenylene group, arylene group, -CO
It is preferably a divalent linking group selected from the group consisting of-, -NH-, -O-, -S- and a combination thereof. The divalent linking group (L) is an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-
And a group obtained by combining at least two divalent groups selected from the group consisting of 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).

The divalent linking group (L) preferably contains a benzene ring and a conjugated double bond. That is, an arylene group and an alkynylene group are adjacent,
It is preferable that the benzene ring of the arylene group and the double bond of the alkynylene group are conjugated. 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 (Q). 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-

When the divalent linking group (L) contains a benzene ring and a conjugated double bond, L16 is particularly preferred. That is, it is particularly preferable that the benzene ring of the AR (arylene group) of L16 and the double bond of the AL (alkynylene group) adjacent on the left side are conjugated. The polymerizable group (Q) in the formula (I) is determined according to the type of the polymerization reaction. Examples of the polymerizable group (Q) are shown below.

[0025]

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The polymerizable group (Q) is an unsaturated polymerizable group (Q1
To Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated polymerizable group, and more preferably an ethylenically unsaturated polymerizable group (Q
1 to Q6) are most preferred. 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 Q 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.

In the present invention, a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group is further added to the optically anisotropic layer. The fluorine compound is a fluorine-containing surfactant, or a repeating unit having a fluorine-substituted alkyl group in a side chain,
It is preferably a copolymer comprising a repeating unit having a hydrophilic group in a side chain. The fluorinated surfactant comprises a hydrophobic group comprising a fluorine-substituted alkyl group, a nonionic, anionic, cationic or amphoteric hydrophilic group and an optional linking group. The fluorine-containing surfactant comprising one hydrophobic group and one hydrophilic group has the following formula (II)
It is represented by I).

[0029] (III) Rf-L ³ -Hy in formula, Rf is selected from the group consisting is fluorine-substituted alkyl group; L ³ is
A single bond or a divalent linking group; and Hy is a hydrophilic group. Rf in the formula (III) functions as a hydrophobic group of the surfactant. The fluorine-substituted alkyl group preferably has 3 to 30 carbon atoms. Some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. It is preferred that 50% or more of the hydrogen atoms contained in the alkyl group be substituted with a fluorine atom, more preferably 60% or more, even more preferably 80% or more, and 90% or more. Is still more preferable, and 100% is most preferably substituted. The remaining hydrogen atoms may be further substituted with another halogen atom (eg, chlorine atom, bromine atom).
Examples of Rf are shown below.

[0030] _{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 :: n-C 7 F 15 - Rf8: Cl- (CF 2 -CFCl) 2 -CF 2 - Rf9: H- (CF 2) 4 - _{Rf10: H- (CF 2) 6} - Rf11: Cl- (CF 2) 6 - Rf12: C 3 F 7 -

In the formula (III), the divalent linking group of L ³ is an alkylene group, an arylene group, a divalent heterocyclic residue, -CO-, -NR- (R is a group having 1 to 5 carbon atoms. Alkyl group or hydrogen atom), —O—, —SO ₂ — and a combination thereof. Examples of L ^{3 in} the formula (III) are shown below. The left side is bonded to the fluorine-substituted alkyl group (Rf), and the right side is bonded to the hydrophilic group (Hy). 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).

[0032] L0: single bond _{L31: -SO 2 -NR- L32: -AL} -O- L33: -CO-NR- L34: -AR-O- L35: -SO 2 -NR-AL-CO-O- L36: -CO-O- L37: -SO 2 -NR-AL-O- L38: -SO 2 -NR-AL- L39: -CO-NR-AL- L40: -AL 1 -O-AL 2 - L41 _{: -Hc-AL- L42: -SO 2} -NR-AL 1 -O-AL 2 - L43: -AR- L44: -O-AR-SO 2 -NR-AL- L45: -O-AR-SO 2 -NR-L46: -O-AR-O-

Hy in the formula (III) is a nonionic hydrophilic group,
Either an anionic hydrophilic group, a cationic hydrophilic group, or a combination thereof (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 from 5 to 30 integer, R ¹ is or 1 to 6 carbon atoms
Alkyl _{group) 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 an integer of 5 to 30, M is a hydrogen atom or an alkali metal atom) Hy7: —OPO (OH) ₂ Hy8: —N ⁺ (CH ₃ ) ₃ .X ⁻ (X is a halogen atom) Hy9 : -COONH ₄

Nonionic hydrophilic groups (Hy1, Hy2, H
y3) is preferable, and a hydrophilic group (Hy1) composed of polyethylene oxide is most preferable. Specific examples of the fluorine-containing surfactant represented by the formula (III) will be shown with reference to the above examples of Rf, L ³ and Hy.

FS-1: Rf1-L31 (R = C ₃ H ₇ )
-Hy1 (n = 6) FS- 2: Rf1-L31 (R = C 3 H 7) -Hy1 (n
= 11) FS-3: Rf1 -L31 (R = C 3 H 7) -Hy1 (n
= 16) FS-4: Rf1 -L31 (R = C 3 H 7) -Hy1 (n
= 21) FS-5: Rf1 -L31 (R = C 2 H 5) -Hy1 (n
= 6) FS-6: Rf1 -L31 (R = C 2 H 5) -Hy1 (n
= 11) FS-7: Rf1 -L31 (R = C 2 H 5) -Hy1 (n
= 16) FS-8: Rf1 -L31 (R = C 2 H 7) -Hy1 (n
= 21) FS-9: Rf2 -L31 (R = C 3 H 7) -Hy1 (n
= 6) FS-10: Rf2 -L31 (R = C 3 H 7) -Hy1 (n
= 11) FS-11: Rf2 -L31 (R = C 3 H 7) -Hy1 (n
= 16) FS-12: Rf2 -L31 (R = C 3 H 7) -Hy1 (n
= 21)

FS-13: Rf3-L32 (AL = CH ₂ )
-Hy1 (n = 5) FS- 14: Rf3-L32 (AL = CH 2) -Hy1 (n
= 10) FS-15: Rf3 -L32 (AL = CH 2) -Hy1 (n
= 15) FS-16: Rf3 -L32 (AL = CH 2) -Hy1 (n
= 20) FS-17: Rf4 -L33 (R = C 3 H 7) -Hy1 (n
= 7) FS-18: Rf4 -L33 (R = C 3 H 7) -Hy1 (n
= 13) FS-19: Rf4 -L33 (R = C 3 H 7) -Hy1 (n
= 19) FS-20: Rf4 -L33 (R = C 3 H 7) -Hy1 (n
= 25) FS-21: Rf5 -L32 (AL = CH 2) -Hy1 (n
= 11) FS-22: Rf5 -L32 (AL = CH 2) -Hy1 (n
= 15) FS-23: Rf5 -L32 (AL = CH 2) -Hy1 (n
= 20) FS-24: Rf5 -L32 (AL = CH 2) -Hy1 (n
= 30)

FS-25: Rf6-L34 (AR = p-phenylene) -Hy1 (n = 11) FS-26: Rf6-L34 (AR = p-phenylene) -Hy
1 (n = 17) FS-27: Rf6-L34 (AR = p-phenylene) -Hy
1 (n = 23) FS-28: Rf6-L34 (AR = p-phenylene) -Hy
1 (n = 29) FS- 29: Rf1-L35 (R = C 3 H 7, AL = CH
_{2) -Hy1 (n = 20)} FS-30: Rf1-L35 (R = C 3 H 7, AL = CH
_{2) -Hy1 (n = 30)} FS-31: Rf1-L35 (R = C 3 H 7, AL = CH
₂ ) -Hy1 (n = 40) FS-32: Rf1-L36-Hy1 (n = 5) FS-33: Rf1-L36-Hy1 (n = 10) FS-34: Rf1-L36-Hy1 (n = 15) ) FS-35: Rf1-L36-Hy1 (n = 20)

FS-36: Rf1-L0-Hy1 (n =
6) FS-37: Rf1-L0-Hy1 (n = 11) FS-38: Rf1-L0-Hy1 (n = 16) FS-39: Rf1-L0-Hy1 (n = 21) FS-40: Rf1- _{L31 (R = C 3 H 7} ) -Hy2 (n
_{^{= 7, R 1 = C 2}} H 5) FS-41: Rf1-L31 (R = C 3 H 7) -Hy2 (n
_{^{= 13, R 1 = C 2}} H 5) FS-42: Rf1-L31 (R = C 3 H 7) -Hy2 (n
_{^{= 20, R 1 = C 2}} H 5) FS-43: Rf1-L31 (R = C 3 H 7) -Hy2 (n
_{^{= 28, R 1 = C 2}} H 5) FS-44: Rf7-L32 (AL = CH 2) -Hy1 (n
= 5) FS-45: Rf7 -L32 (AL = CH 2) -Hy1 (n
= 10) FS-46: Rf7 -L32 (AL = CH 2) -Hy1 (n
= 15) FS-47: Rf7 -L32 (AL = CH 2) -Hy1 (n
= 20)

FS-48: Rf1-L37 (R = C ₃ H ₇ ,
_{AL = CH 2 CH 2) -Hy3} (n = 5) FS-49: Rf1-L37 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 7} ) FS-50: Rf1-L37 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 9} ) FS-51: Rf1-L37 (R = C 3 H 7, AL = CH 2 C
_{H 2) -Hy3 (n = 12} ) FS-52: Rf8-L0-Hy4 (M = H) FS-53: Rf3-L0-Hy4 (M = H) FS-54: Rf1-L38 (R = C 3 H ₇ , AL = CH
_{2) -Hy4 (M = K)} FS-55: Rf4-L39 (R = C 3 H 7, AL = CH
_{2) -Hy4 (M = Na)} FS-56: Rf1-L0-Hy5 (M = K) FS-57: Rf9-L40 (AL 1 = CH 2, AL 2 = CH 2 C
_{H 2) -Hy5 (M = Na} ) FS-58: Rf10-L40 (AL 1 = CH 2, AL 2 = CH 2 C
_{H 2) -Hy5 (M = Na} ) FS-59: Rf5-L40 (AL 1 = CH 2, AL 2 = CH 2 C
_{H 2) -Hy5 (M = Na} )

FS-60: Rf1-L38 (R = C ₃ H ₇ , AL
_{= CH 2 CH 2 CH 2)} -Hy5 (M = Na) FS-61: Rf1-L31 (R = C 3 H 7) -Hy6 (n
= 5, M = Na) FS -62: Rf1-L31 (R = C 3 H 7) -Hy6 (n
= 10, M = Na) FS -63: Rf1-L31 (R = C 3 H 7) -Hy6 (n
= 15, M = Na) FS -64: Rf1-L31 (R = C 3 H 7) -Hy6 (n
= 20, M = Na) FS -65: Rf1-L38 (R = C 2 H 5, AL = CH 2
_{CH 2) -Hy7 FS-66:} Rf1-L38 (R = H, AL = CH 2 CH 2 CH 2)
-Hy8 (X = I) FS-67: Rf10-L41 (Hc below, AL = CH ₂ CH ₂ CH
₂ ) -Hy6 (M is dissociated)

[0042]

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FS-68: Rf1-L42 (R = C ₃ H ₇ , AL ¹ = CH ₂ C
^{_{H 2, AL 2 = CH 2}} CH 2 CH 2) -Hy6 (M = Na) FS-69: Rf11-L0-Hy5 (M = Na) FS-70: Rf12-L43 (AR = o- phenylene) -Hy
6 (M = K) FS-71: Rf12-L43 (AR = m-phenylene) -Hy
6 (M = K) FS-72: Rf12-L43 (AR = p-phenylene) -Hy
6 (M = K) FS- 73: Rf6-L44 (R = C 2 H 5, AL = CH 2 CH 2) -
Hy5 (M = H) FS-74: Rf6-L45 (AR = p-phenylene, R = C _{2
H 5) -Hy1 (n = 9} ) FS-75: Rf6-L45 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 14} ) FS-76: Rf6-L45 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 19} ) FS-77: Rf6-L45 (AR = p- phenylene, R = C _{2
H 5) -Hy1 (n = 28} ) FS-78: Rf6-L46 (AR = p- -phenylene) -Hy
1 (n = 5) FS-79: Rf6-L46 (AR = p-phenylene) -Hy
1 (n = 10) FS-80: Rf6-L46 (AR = p-phenylene) -Hy
1 (n = 15) FS-81: Rf6-L46 (AR = p-phenylene) -Hy
1 (n = 20)

A fluorinated surfactant having two or more fluorine-substituted alkyl groups (hydrophobic groups) or hydrophilic groups may be used. Examples of the fluorinated surfactant having two or more hydrophobic groups or hydrophilic groups are shown below.

[0045]

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FS-82: n1 + n2 = 12, FS-83: n1 + n2
= 18, FS-84: n1 + n2 = 24

[0047]

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FS-85: n1 + n2 = 20, FS-86: n1 + n2
= 30, FS-87: n1 + n2 = 40

[0049]

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FS-88: n = 5, FS-89: n = 10, F
S-90: n = 15, FS-91: n = 20

[0051]

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For surfactants, various references (eg,
Hiroshi Horiguchi, `` New surfactant, '' Sankyo Publishing (1975), MJ Schic
k, Nonionic Surfactants, Marcell Dekker Inc., New
York, (1967), JP-A-7-13293).

The copolymer comprising a repeating unit having a fluorine-substituted alkyl group on the side chain and a repeating unit having a hydrophilic group on the side chain preferably has a hydrocarbon main chain, and is obtained by polymerization of an ethylenically unsaturated monomer. It is more preferred to have the resulting main chain. A preferred copolymer is represented by the following formula (IV).

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In the formula, R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Rf is a fluorine-substituted alkyl group; L ³¹ and L ³² are each independently a single bond or a double bond. Hy is a hydrophilic group; n is 1 to 99 (mol%);
Is 1 to 99 (mol%). . In the formula (IV), R is preferably a hydrogen atom or methyl. Rf is the same as Rf in formula (III). L ³¹
And L ³² is the same as L ³ in formula (III). H
y is the same as Hy in the formula (III).

Two or more fluorine compounds may be used in combination. The fluorine compound is added to the optically anisotropic layer in an amount of 1 to 35 mg /
Preferably, it is added in an amount of m ² .

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

The discotic liquid crystal molecules are preferably oriented substantially uniformly, and more preferably are fixed in a state where they are substantially uniformly oriented. Most preferably, it is fixed. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reactions are preferred. Examples of photopolymerization initiators include α
-Carbonyl compounds (U.S. Pat.
369670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compounds (described in US Pat. No. 272251)
No. 2), polynuclear quinone compounds (US Pat. No. 304)
Nos. 6127 and 2951758), 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, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. 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 uses ultraviolet light.
The irradiation energy is 20 mJ / cm ^{2 to} 50 J / cm
² , preferably 100 to 800 mJ / cm
More preferably, it is ² . Light irradiation may be performed under heating conditions to promote the photopolymerization reaction. The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm,
Most preferably, it is 1 to 10 μm.

[Transparent Support] As the transparent support of the optical compensation sheet, an optically isotropic polymer film is generally used. The support is transparent when the light transmittance is 8
It means 0% 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 retardation in the thickness direction (Rt
h) is preferably 40 nm or less, and 20 nm
It is more preferred that: The in-plane retardation (Re) and the thickness direction retardation (Rth) of the transparent support are defined by the following formulas. Re = (nx−ny) × d Rth = [{(nx + ny) / 2} −nz] × d where nx and ny are in-plane refractive indices of the transparent support, and nz is the thickness of the transparent support. Is the refractive index in the direction, and d is the thickness of the transparent support.

Depending on the type of liquid crystal display mode, an optically anisotropic polymer film may be used as the transparent support. That is, the optical anisotropy of the optically anisotropic layer may be added to the optical anisotropy of the transparent support to correspond to (optically compensate) the optical anisotropy of the liquid crystal cell in some cases.
When an optically anisotropic transparent support is used for such a purpose, the in-plane retardation (Re) of the transparent support is 2
It is preferably at least 0 nm, more preferably at least 30 nm. Further, the thickness direction retardation (Rth) is preferably 80 nm or more,
More preferably, it is 120 nm or more.

The material forming the transparent support is determined depending on whether it is an optically isotropic support or an optically anisotropic support. In the case of an optically isotropic support, glass or cellulose ester is generally used. In the case of an optically anisotropic support, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin) is generally used. The optical anisotropy is obtained by stretching the synthetic polymer film. However, European patent 0
High retardation is obtained by (1) use of a retardation increasing agent, (2) reduction of acetylation degree of cellulose acetate, or (3) production of a film by a cooling dissolution method described in JP-A-911656A2 (optical). Cellulose anisotropic film). The cellulose ester or synthetic polymer film is preferably formed by a solvent casting method. The thickness of the transparent support is preferably from 20 to 500 μm, more preferably from 50 to 200 μm. To improve the adhesion between the transparent support and the layer provided thereon (adhesive layer, alignment film or optically anisotropic layer), the transparent support is subjected to a surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light ( UV) treatment, flame treatment)
May be implemented. An adhesive layer (undercoat layer) may be provided on the transparent support.

[Alignment Film] The alignment film is formed by rubbing an organic compound (preferably a polymer), obliquely depositing an inorganic compound, forming a layer having microgrooves, or using an organic compound by a Langmuir-Blodgett method (LB film). (Eg, ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate). In addition, the application of an electric field,
There is also known an alignment film in which an alignment function is generated by applying a magnetic field or irradiating light. An alignment film formed by rubbing a polymer is particularly preferable. The rubbing treatment is performed by rubbing the surface of the polymer layer several times with paper or cloth in a certain direction. With respect to the type of polymer used for the alignment film, there is a document on an optical compensatory sheet using discotic liquid crystal molecules corresponding to various display modes described above. The thickness of the alignment film is 0.01 to 5 μm
Is preferably, and more preferably, 0.05 to 1 μm. The optically anisotropic layer may be transferred onto a transparent support after the discotic liquid crystalline molecules of the optically anisotropic layer are aligned using an alignment film. Discotic liquid crystalline molecules fixed in an aligned state can maintain the aligned state without an alignment film.

[Polarizing Film] As the polarizing film, an iodine-based polarizing film,
There are 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 corresponds to a direction perpendicular to the stretching direction of the film.

[Transparent Protective Film] The protective film is transparent.
It means that the light transmittance is 80% or more. As the transparent protective film, a cellulose ester film, preferably a triacetyl cellulose film, is generally used.
The cellulose ester film is preferably formed by a solvent casting method. The thickness of the transparent protective film is
It is preferably 20 to 500 μm, and 50 to 2 μm.
More preferably, it is 00 μm.

[Liquid Crystal Display Device] The present invention can be applied to liquid crystal cells of various display modes. As described above, the optical compensation sheet using discotic liquid crystal molecules is TN
(Twisted Nematic), IPS (In-Plane Switchin)
g), FLC (Ferroelectric Liquid Crystal), OC
B (Optically Compensatory Bend), STN (Supper
Devices corresponding to liquid crystal cells of Twisted Nematic), VA (Vertically Aligned) and HAN (Hybrid Aligned Nematic) modes have already been proposed. The present invention relates to TN
This is particularly effective in a (Twisted Nematic) mode liquid crystal display device.

[0066]

EXAMPLES [Example 1] (Preparation of transparent support) The following components were charged into a mixing tank, and heated and stirred to prepare a cellulose acetate solution (dope).

<< Composition of Cellulose Acetate Solution >>セ ル ロ ー ス 100% by weight of cellulose acetate with a degree of acetylation of 60.9% 6.5 parts by weight of triphenyl phosphate Biphenyl diphenyl phosphate 5.2 parts by weight The following retardation increasing agent (1) 0.1 parts by weight The following retardation increasing agent (2) 0.2 parts by weight Methylene chloride 310.25 parts by weight Methanol 54.75 parts by weight 1 -Butanol 10.95 parts by weight ────────────────────────────────────

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The obtained dope was cast on a drum cooled to 0 ° C. from a casting port. The film is peeled off at a solvent content of 70% by weight, and both ends in the width direction of the film are fixed with a pin tenter, and the stretching ratio in the width direction (direction perpendicular to the machine direction) is 3 to 5% by weight. While maintaining an interval of 3%. After that, it is further dried by being transported between the rolls of the heat treatment apparatus, and has a glass transition temperature of 1
The stretching ratio in the machine direction is substantially 0% in a region exceeding 20 ° C.
The ratio of the stretching ratio in the width direction to the stretching ratio in the machine direction is 0.7 (considering that the film is stretched 4% in the machine direction when stripping).
By adjusting to be 5, a cellulose acetate film having a thickness of 100 μm was produced. When the retardation of the produced film was measured at a wavelength of 632.8 nm, the retardation in the thickness direction was 40 nm and the in-plane retardation was 4 nm. The prepared cellulose acetate film was used as a transparent support.

(Formation of First Undercoat Layer) On a transparent support, a coating solution having the following composition was applied at 28 ml / m ² and dried to form a first undercoat layer.

<< Composition of First Undercoat Layer Coating Solution >> ──────────────────────────────── Gelatin 5.42 parts by weight Formaldehyde 1.36 parts by weight Salicylic acid 1.60 parts by weight Acetone 391 parts by weight Methanol 158 parts by weight Methylene chloride 406 parts by weight Water 12 parts by weight ───────────────────────────────── ───

(Formation of Second Undercoat Layer) On the first undercoat layer, a coating solution having the following composition was applied at 7 ml / m ² and dried to form a second undercoat layer.

<< Composition of Coating Solution for Second Undercoat Layer >> ──────────────────────────────── The following anionic polymer 0.79 parts by weight citric acid monoethyl ester 10.1 Parts by weight Acetone 200 parts by weight Methanol 877 parts by weight Water 40.5 parts by weight ────────────────────────────────── ──

[0075]

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(Formation of Back Layer) A coating solution having the following composition was applied on the opposite side of the transparent support at a rate of 25 ml / m ² and dried to form a back layer.

組成 Composition of coating solution for back layer ──────セ ル ロ ー ス Cellulose diacetate with 55% acetylation degree 6.56 parts by weight Silica-based matting agent (average Particle size: 1 μm) 0.65 parts by weight Acetone 679 parts by weight Methanol 104 parts by weight ────

(Formation of Alignment Film) On the second undercoat layer, an aqueous solution of a long-chain alkyl-modified polyvinyl alcohol was applied and dried with warm air at 60 ° C. for 90 seconds, and then rubbed to form an alignment film. . The rubbing direction of the alignment film was parallel to the casting direction of the transparent support.

(Formation of Optically Anisotropic Layer) On the alignment film, a coating solution having the following composition was applied using a # 4 wire bar. The application amount of the fluorine-containing compound was 25.8 mg.
/ M ² .

<< Coating Liquid for Optically Anisotropic Layer >> ──────────────────────────────── The following discotic liquid crystalline compound 90 parts by weight Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 10 parts by weight The following photopolymerization initiator 3 parts by weight The following fluorinated surfactant 1.5 parts by weight Methyl ethyl ketone 295.5 parts by weight ──────────────────────────────

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[0082]

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The coating layer was heated in a thermostat at 130 ° C. for 3 minutes to orient the discotic liquid crystalline compound. Then, ultraviolet rays were irradiated for 1 minute using a 120 W / cm high-pressure mercury lamp to polymerize the discotic liquid crystal compound and fix the alignment state. After cooling to room temperature, an optical compensation sheet was produced. About the produced optical compensation sheet,
The minimum tilt angle and the maximum tilt angle of the discotic liquid crystalline molecules were measured. The tilt angle of the discotic liquid crystal molecules changed with the distance between the discotic liquid crystal molecules and the surface of the transparent support, with the minimum value near the alignment film and the maximum value near the air interface. Further, the average inclination angle (β) of the entire optical compensation sheet was measured. Further, the retardation (Rth) in the thickness direction of the optical compensation sheet was measured. The results are shown in Table 1.

(Production of Liquid Crystal Display) A polyimide alignment film was provided on a glass substrate provided with an ITO transparent electrode, and a rubbing treatment was performed. Two substrates were stacked via a 5 μm spacer so that the alignment films faced each other. The two substrates were arranged such 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 & Co.) to form a rod-shaped liquid crystal layer. The Δn of the rod-like liquid crystal molecules was 0.0969. On both sides of the TN liquid crystal cell produced as described above, two optical compensation sheets produced were stuck so that the optically anisotropic layer faced the substrate of the liquid crystal cell. Further, two polarizing plates were stuck on the outside of them to produce a type liquid crystal display device. The rubbing direction of the alignment film of the optical compensation sheet and the rubbing direction of the alignment film of the liquid crystal cell adjacent thereto were arranged so as to be antiparallel. The liquid crystal cell was arranged such that the absorption axis of the polarizing plate was parallel to the rubbing direction of the liquid crystal cell. A voltage is applied to the liquid crystal cell of the liquid crystal display device, and the transmittance between white display and black display at 2 V for white display and 5 V for black display is defined as a contrast ratio, and a contrast ratio of 10 at the top, bottom, left and right and a region without gradation inversion is viewed. Measured as corners. The results are shown in Table 1.

Example 2 An optical compensatory sheet and a liquid crystal display were produced and evaluated in the same manner as in Example 1 except that the coating liquid for the optically anisotropic layer was changed to the following composition. The results are shown in Table 1. The amount of the fluorine-containing compound applied was 8.
It was 7 mg / m ² .

<< Coating Liquid for Optically Anisotropic Layer >>デ ィ ス 90 parts by weight of the discotic liquid crystalline compound used in Example 1 Methylol propane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 10 parts by weight Photopolymerization initiator used in Example 1 3 parts by weight Fluorine-containing polymer described below 0.5 part by weight ────────────────────────────────────

[0088]

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Comparative Example 1 An optical compensatory sheet and a liquid crystal display were produced and evaluated in the same manner as in Example 1 except that the fluorine-containing compound was not added to the coating liquid for the optically anisotropic layer. The results are shown in Table 1.

[0090]

Table 1 Table 1 Optical Compensation Tilt Angle of Fluorine DLC Average tilt Rth letter viewing angle sheet Compound Minimum Maximum Bevel Angle β Up / Down / Left / Right ────────────────────────────────── Example 1 Activator 13 degrees 67 degrees 27 degrees 129 nm 91 degrees 148 degrees Example 2 Polymer 13 degrees 67 degrees 27 degrees 129 nm 91 degrees 148 degrees Comparative Example 1 None 4 degrees 51 degrees 19 degrees 141 nm 71 degrees 112 degrees ──────────────────────────────────

[Example 3] (Preparation of transparent support) The following components were charged into a mixing tank, and heated and stirred to prepare a cellulose acetate solution.

<< Composition of Cellulose Acetate Solution >>セ ル ロ ー ス 100% by weight of cellulose acetate having a degree of acetylation of 60.9% 7.8 parts by weight of triphenyl phosphate Biphenyl diphenyl phosphate 3.9 parts by weight Methylene chloride 300 parts by weight Methanol 54 parts by weight 1-butanol 11 parts by weight ─────────────────────────── ─────────

The following components were charged into another mixing tank, and heated and stirred to prepare a retardation increasing solution.

{Composition of Retardation Elevator Solution} ─────────────────────────────── 2-hydroxy-4-benzyloxybenzophenone 12 parts by weight 2,4-benzyloxybenzophenone 4 parts by weight Methylene chloride 80 parts by weight Methanol 20 parts by weight ────────────────────────────────────

To 474 parts by weight of the cellulose acetate solution, 22 parts by weight of a retardation increasing solution was added,
The dope was prepared by sufficiently stirring. The amount of the retardation increasing agent was 3 parts by weight based on 100 parts by weight of cellulose acetate. The obtained dope was poured from the casting port to 0 ° C.
On a cooled drum. Solvent content 70% by weight
The film is peeled off, and both ends in the width direction of the film are fixed with a pin tenter. In a region where the solvent content is 3 to 5% by weight,
Drying was performed while maintaining an interval at which the stretching ratio in the width direction (direction perpendicular to the machine direction) was 3%. Thereafter, the film is further dried by being conveyed between rolls of a heat treatment apparatus, and the stretching ratio in the machine direction is substantially zero in a region where the glass transition temperature exceeds 120 ° C.
%, Taking into account that the stretching ratio in the width direction and the stretching ratio in the machine direction are 0.
The thickness was adjusted to 75 to prepare a cellulose acetate film having a thickness of 107 μm. When the retardation of the produced film was measured at a wavelength of 632.8 nm, the retardation in the thickness direction was 80 nm, and the in-plane retardation was 11 nm. The prepared cellulose acetate film was used as a transparent support.

(Formation of First Undercoat Layer) On a transparent support, a coating solution having the following composition was applied at a rate of 28 ml / m ² and dried to form a first undercoat layer.

<< Composition of First Undercoat Layer Coating Solution >> ──────────────────────────────── Gelatin 5.42 parts by weight Formaldehyde 1.36 parts by weight Salicylic acid 1.60 parts by weight Acetone 391 parts by weight Methanol 158 parts by weight Methylene chloride 406 parts by weight Water 12 parts by weight ───────────────────────────────── ───

(Formation of Second Undercoat Layer) Onto the first undercoat layer, a coating solution having the following composition was applied at 7 ml / m ² and dried to form a second undercoat layer.

<< Composition of Coating Solution for Second Undercoat Layer >>ア ニ オ ン 0.79 parts by weight of the anionic polymer used in Example 1 monoethyl citrate Ester 10.1 parts by weight Acetone 200 parts by weight Methanol 877 parts by weight Water 40.5 parts by weight ────────────────────────────── ──────

(Formation of Back Layer) A coating solution having the following composition was applied at 25 ml / m ² on the opposite surface of the transparent support, and dried to form a back layer.

組成 Composition of coating solution for back layer ──────セ ル ロ ー ス Cellulose diacetate with 55% acetylation degree 6.56 parts by weight Silica-based matting agent (average Particle size: 1 μm) 0.65 parts by weight Acetone 679 parts by weight Methanol 104 parts by weight ────

(Formation of Alignment Film) On the second undercoat layer, an aqueous solution of a long-chain alkyl-modified polyvinyl alcohol was applied and dried with hot air at 60 ° C. for 90 seconds, and then rubbed to form an alignment film. . The rubbing direction of the alignment film was parallel to the casting direction of the transparent support.

(Formation of Optically Anisotropic Layer) The coating liquid for the optically anisotropic layer used in Example 1 was applied on the alignment film using a # 4 wire bar. The amount of the fluorine-containing compound applied was 25.8 mg / m ² . The coating layer was heated in a thermostat at 130 ° C. for 3 minutes to align the discotic liquid crystalline compound. Then, ultraviolet rays were irradiated for 1 minute using a 120 W / cm high-pressure mercury lamp to polymerize the discotic liquid crystal compound and fix the alignment state. After cooling to room temperature, an optical compensation sheet was produced. The minimum tilt angle and the maximum tilt angle of the discotic liquid crystal molecules were measured for the prepared optical compensation sheet. The tilt angle of the discotic liquid crystal molecules changed with the distance between the discotic liquid crystal molecules and the surface of the transparent support, with the minimum value near the alignment film and the maximum value near the air interface. Further, the average inclination angle (β) of the entire optical compensation sheet was measured. Further, the retardation (R
th) was measured. The results are shown in Table 2.

(Preparation of Elliptical Polarizing Plate) Iodine was adsorbed to a stretched polyvinyl alcohol film to prepare a polarizing film. One surface of the polarizing film and the transparent support surface of the produced optical compensation sheet were adhered using a polyvinyl alcohol-based adhesive. The transmission axis of the polarizing film and the slow axis of the optical compensation sheet were arranged in parallel. A transparent protective film was attached to the opposite surface of the polarizing film using a polyvinyl alcohol-based adhesive. Thus, an elliptically polarizing plate was produced.

(Production of Liquid Crystal Display) 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 two substrates were arranged such 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 & Co.) to form a rod-shaped liquid crystal layer. The Δn of the rod-like liquid crystal molecules was 0.0969. On both sides of the TN liquid crystal cell produced as described above, two elliptically polarizing plates produced were stuck so that the optically anisotropic layer faced the substrate of the liquid crystal cell. The slow axis of the optical compensation sheet and the rubbing direction of the alignment film of the liquid crystal cell were arranged so as to be orthogonal to each other. A voltage is applied to the liquid crystal cell of the liquid crystal display device, and the transmittance between white display and black display at 2 V for white display and 5 V for black display is defined as a contrast ratio, and a contrast ratio of 10 at the top, bottom, left and right and a region without gradation inversion is viewed. Measured as corners. The results are shown in Table 2.

Example 4 An elliptically polarizing plate and a liquid crystal display device were evaluated in the same manner as in Example 3, except that the composition of the optically anisotropic layer coating solution was changed to the composition used in Example 2.
The results are shown in Table 2. The application amount of the fluorine-containing compound was 8.7 mg / m ² .

Comparative Example 2 An elliptically polarizing plate and a liquid crystal display were produced and evaluated in the same manner as in Example 3 except that the fluorine-containing compound was not added to the coating solution for the optically anisotropic layer.
The results are shown in Table 2.

[0108]

[Table 2] Table 2 ──────────────────────────────────── Ellipse Average of inclination angle of fluorine DLC Tilt Rth Letter Viewing Angle Polarizer Compound Minimum Maximum Oblique Angle β Example 3 Activator 13 degrees 67 degrees 19 degrees 163 nm 91 degrees 148 degrees Example 4 Polymer 13 degrees 67 degrees 19 degrees 163 nm 91 degrees 148 degrees Comparative Example 2 None 4 degrees 51 degrees 14 degrees 180 nm 71 degrees 112 degrees ──────────────────────────────────

Claims (8)

[Claims] 1. An optical compensation sheet having an optically anisotropic layer formed from discotic liquid crystal molecules and a transparent support, wherein the tilt angle of the discotic liquid crystal molecules is equal to that of the discotic liquid crystal molecules. An optical compensation sheet which changes with the distance from the body surface, wherein the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. 2. The optical compensation sheet according to claim 1, wherein the optically anisotropic layer contains a fluorine compound in an amount of 1 to 35 mg / m ² . 3. The optical compensation sheet according to claim 1, wherein the fluorine compound is a fluorine-containing surfactant. 4. The optical compensation sheet according to claim 1, wherein the fluorine compound is a copolymer comprising a repeating unit having a fluorine-substituted alkyl group in a side chain and a repeating unit having a hydrophilic group in a side chain. 5. The optical compensation sheet according to claim 1, wherein the discotic liquid crystal molecule has a molecular structure in which a side chain containing a benzene ring and a double bond conjugated thereto is bonded to a discotic nucleus. 6. A transmissive liquid crystal display device comprising a TN mode liquid crystal cell and two polarizing plates disposed on both sides thereof, wherein at least one of the polarizing plates and the liquid crystal cell are provided.
An optical compensation sheet having an optically anisotropic layer formed of discotic liquid crystal molecules and a transparent support is disposed, and the tilt angle of the discotic liquid crystal molecules is adjusted to the distance between the discotic liquid crystal molecules and the transparent support surface. The liquid crystal display device, wherein the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. 7. An elliptically polarizing plate comprising an optically anisotropic layer formed from discotic liquid crystal molecules, a transparent support, a polarizing film and a transparent protective film laminated in this order, wherein the discotic liquid crystal molecules are The tilt angle changes with the distance between the discotic liquid crystalline molecule and the transparent support surface, and the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group. Elliptically polarizing plate. 8. A transmission type liquid crystal display device comprising a TN mode liquid crystal cell and two polarizing plates disposed on both sides thereof, wherein at least one of the polarizing plates is formed of discotic liquid crystal molecules. Anisotropic layer, transparent support,
It is an elliptically polarizing plate in which a polarizing film and a transparent protective film are laminated in this order, and the tilt angle of the discotic liquid crystal molecules is
A liquid crystal display, wherein the optically anisotropic layer further contains a fluorine compound having a fluorine-substituted alkyl group and a hydrophilic group, which changes with the distance between the discotic liquid crystal molecule and the transparent support surface. apparatus.