JP2008058589A - Optical compensation film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

An optical compensation film having a phase difference sufficient to optically compensate a liquid crystal cell, a polarizing plate, and a liquid crystal display device capable of preventing light leakage and obtaining good contrast.
A first optically anisotropic layer formed from a composition containing a liquid crystalline compound and a second optically anisotropic layer, wherein the first optically anisotropic layer has the formula: 2 <Re (40) / Re (−40) <7, and the intersection angle between the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer is An optical compensation film or the like that is not orthogonal or parallel.
[Selection] Figure 2

Description

  The present invention relates to an optical compensation film, a polarizing plate using the optical compensation film, and a liquid crystal display device having the polarizing plate.

A liquid crystal display (LCD) has significant advantages such as thinness, light weight, and low power consumption as compared with a CRT (Cathode Ray Tube). The liquid crystal display device includes a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell. The liquid crystal cell includes a liquid crystal molecule, two substrates enclosing it, and an electrode layer for applying a voltage to the liquid crystal molecule.
Moreover, in order to align the liquid crystal molecules enclosed, two substrates are usually provided with an alignment film.
Moreover, in order to remove the coloring of the image displayed on the liquid crystal cell, an optical compensation film (retardation plate) is often provided between the liquid crystal cell and the polarizing plate.
The laminate of the polarizing plate (polarizing film) and the optical compensation film functions as an elliptically polarizing plate. Moreover, the function which expands the viewing angle of a liquid crystal cell may be provided to an optical compensation film. As the optical compensation film, a stretched birefringent film has been conventionally used.

It has been proposed to use an optical compensation film having an optically anisotropic layer containing a discotic compound in place of the stretched birefringent film (see, for example, Patent Documents 1 to 4).
The optically anisotropic layer is formed by orienting a discotic compound and fixing the orientation state. This discotic compound generally has a large birefringence. In addition, the discotic compound has various orientation forms.
Therefore, by using a discotic compound, an optical compensation film having optical properties that cannot be obtained by a conventional stretched birefringent film can be produced.

For example, a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell has been proposed (for example, (See Patent Documents 5 and 6).
In such a liquid crystal display device, since the rod-like liquid crystal molecules are symmetrically aligned at the upper part and the lower part of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode.
The bend alignment mode liquid crystal display device has an advantage of a high response speed.

The bend alignment mode is characterized by a wide viewing angle and a high response speed compared to general liquid crystal modes (TN mode and STN mode).
However, further improvement is required compared to CRT. In order to further improve the bend alignment mode liquid crystal display device, it is conceivable to use an optical compensation film in the same manner as in the general liquid crystal mode.
However, a conventional optical compensation film made of a stretched birefringent film has an insufficient optical compensation function in a bend alignment mode liquid crystal display device.
As described above, it has been proposed to use an optical compensation film having an optically anisotropic layer containing a discotic compound and a transparent support instead of the stretched birefringent film.
Further, a bend alignment mode liquid crystal display device using an optical compensation film containing a discotic compound has also been proposed (see, for example, Patent Documents 7 and 8).
By using the optical compensation film containing the discotic compound, the viewing angle of the liquid crystal display device in the bend alignment mode is remarkably improved.

When an optical compensation film containing a discotic compound is used in a bend alignment mode liquid crystal display device, there is a problem that light of a specific wavelength leaks and a display image is colored (for example, refer to Patent Document 9). .
It is described that the cause of this coloring is the wavelength dependency of the transmittance of the elliptically polarizing plate (a laminate of a polarizing film and an optical compensation film).
Then, the optical anisotropy is performed so that the angle between the average direction of the orthogonal projection of the discotic normal to the optically anisotropic layer and the in-plane transmission axis of the polarizing film is substantially 45 °. It has been reported that the maximum optical compensation effect for a bend alignment mode liquid crystal cell can be obtained by disposing a conductive layer and a polarizing film.
Various methods have been proposed for a bend alignment liquid crystal device using an optical compensation film containing a discotic compound in order to reduce color change and prevent gradation inversion (for example, Patent Document 10, 11).

By the way, in the medium-sized and small-sized liquid crystal display devices, compared with a large-sized liquid crystal display device, a voltage is not applied to the liquid crystal cell so much, so when a voltage is applied to the liquid crystal cell, that is, in black display, The bend of the liquid crystal cell in the medium-sized and small-sized liquid crystal display devices becomes slightly gentler than the bend of the liquid crystal cell in the large-sized liquid crystal display device.
Therefore, the phase difference of the liquid crystal cell in the medium-sized and small-sized liquid crystal display devices is larger than the phase difference of the liquid crystal cell in the large-sized display device. Therefore, the phase difference is adjusted to the liquid crystal cell so as to absorb this phase difference. It is necessary to increase the phase difference of the designed optical compensation film, and conventionally, this has been dealt with by increasing the thickness of the optical compensation film.
However, a countermeasure such as increasing the thickness of the optical compensation film leads to an increase in cost, and causes optical nonuniformity and a long alignment time of the liquid crystal. As a result, the optical compensation film, etc. The productivity of was supposed to be inferior.
Therefore, there has been a demand for an optical compensation film, a polarizing plate, and a liquid crystal display device in which the retardation is increased without increasing the thickness.

JP-A-6-214116 US Pat. No. 5,583,679 US Pat. No. 5,646,703 German Patent Application Publication No. 3911620 US Pat. No. 4,583,825 US Pat. No. 5,410,422 JP-A-9-197397 International Publication WO96 / 37804 Pamphlet JP 11-316378 A Patent registration No. 3069997 JP 2002-40429 A

An object of the present invention is to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide an optical compensation film and a polarizing plate having a phase difference sufficient for optically compensating a liquid crystal cell.
Another object of the present invention is to provide a liquid crystal display device that prevents light leakage and obtains good contrast.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies and as a result, obtained the following findings. That is, the phase difference in the thickness direction is obtained with respect to the tilt angle of the liquid crystal molecules included in the first optical anisotropic layer constituting the optical compensation film, which is gentle in the vicinity of the alignment film and close to perpendicular on the air interface side. This is possible by adjusting the tilt angle on the air interface side, and is the finding that the liquid crystal molecules on the air interface side are vertically aligned using an additive distributed on the air interface side.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A first optically anisotropic layer and a second optically anisotropic layer formed from a composition containing a liquid crystal compound, wherein the first optically anisotropic layer has the following formula ( 1) and the crossing angle between the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is not orthogonal and parallel. It is a film.
2 <Re (40) / Re (−40) <7 Equation (1)
In the mathematical formula (1), Re (40) is measured from a direction inclined by (+) 40 degrees with respect to the slow axis of the first optically anisotropic layer as an axis from the normal line of the optical compensation film. Retardation value of the first optically anisotropic layer is represented, Re (−40) is −40 degrees from the normal line of the optical compensation film with the slow axis of the first optically anisotropic layer as an axis. It represents the retardation value of the first optically anisotropic layer measured from the inclined direction. However, Re (40)> Re (−40).
<2> The optical compensation film according to <1>, wherein the retardation value Re (0) measured from the normal direction of the first optically anisotropic layer satisfies the following mathematical formula (2).
35 <Re (0) <60 ......... Formula (2)
<3> At least one fluoroaliphatic group-containing polymer containing a repeating unit derived from the monomer represented by the following general formula (2) and general formula (3) is included in the first optically anisotropic layer. The optical compensation film according to any one of <1> to <2>.
(In General Formula (2), R ₁ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom, or —N (R ₂ ) — (R ₂ represents a hydrogen atom or a carbon number of 1 to 3). 4 represents an alkyl group of 4.), Z represents a hydrogen atom or a fluorine atom, m represents an integer of 1 to 6, and n represents an integer of 2 to 4.)
(In General Formula (3), A is a divalent (q = 1) or trivalent (q = 2) linking group selected from the following linking group group A, or 2 selected from the linking group group A below. Represents a divalent (q = 1) or trivalent (q = 2) linking group formed by combining two or more, the linking groups may be bonded to each other through an oxygen atom, and Z is a hydrogen atom Or represents a fluorine atom, p represents an integer of 3 to 8, and q represents 1 or 2.)
(Linking group A)
_{-CH 2 -, - CH 2 CH} 2 -, - CH 2 CH 2 CH 2 -, - C 6 H 4 -, and _{-C 6 H 3 <(- C} 6 H 4 -, and -C ₆ H ₃ < The substitution position on the benzene ring may be any position.)
<4> The optical compensation film according to any one of <1> to <3>, wherein the first optically anisotropic layer has a thickness of 1.7 μm or less.
<5> The optical compensation film according to any one of <1> to <4>, wherein the liquid crystal compound is a discotic liquid crystalline compound.
<6> The optical compensation film according to any one of <1> to <5>, wherein the second optically anisotropic layer is a cellulose acylate film.
<7> A polarizing plate comprising the optical compensation film according to any one of <1> to <6> and a polarizing film.
<8> A liquid crystal display device comprising a liquid crystal cell and the polarizing plate according to <7>.
<9> The liquid crystal display device according to <7>, wherein a voltage applied to the liquid crystal cell is 5 V or less.
<10> The liquid crystal display device according to any one of <8> to <9>, wherein the liquid crystal cell is an OCB method or an ECB method.

ADVANTAGE OF THE INVENTION According to this invention, the optical compensation film and polarizing plate which have a phase difference sufficient for carrying out optical compensation (for example, optical compensation at the time of black display of the liquid crystal cell of OCB, ECB mode) can be provided. .
Further, according to the present invention, it is possible to provide a liquid crystal display device that prevents light leakage and obtains good contrast.

Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Further, in this specification, “parallel” and “orthogonal” mean that the angle is within a range of strictly less than ± 10 °. In this range, an error from a strict angle is preferably less than ± 5 °, and more preferably less than ± 2 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index and the phase difference is a value at λ = 550 nm in the visible light region unless otherwise specified.
Further, in this specification, the “polarizing plate” is cut into a size to be incorporated into a long polarizing plate and a liquid crystal device unless otherwise specified (in this specification, “cutting” includes “punching” and The term “includes“ cutout ”and the like” is used to include both polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other. “Polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. It shall be.

In the description of the present embodiment, the “molecular symmetry axis” refers to a symmetry axis when the molecule has a rotational symmetry axis, but strictly requires that the molecule is rotationally symmetric. is not.
In general, in a discotic liquid crystalline compound, the molecular symmetry axis coincides with an axis perpendicular to the disc surface passing through the center of the disc surface, and in a rod-like liquid crystalline compound, the molecular symmetry axis is the major axis of the molecule. Match.

In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light of wavelength λ nm is incident from each of the inclined directions in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction (with the direction of the rotation axis as the rotation axis). KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
The retardation value is measured from two inclined directions with the slow axis as the tilt axis (rotation axis) (if there is no slow axis, the arbitrary direction in the film plane is the rotation axis). Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (A) and (B).
... Formula (A)
However, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction.
Further, nx in the formula (A) represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, and nz represents the refraction in the direction orthogonal to nx and ny. Represents a rate.
Rth = ((nx + ny) / 2−nz) × d (Equation (B)
When the film to be measured is a film that cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotary axis), and −50 degrees to +50 degrees with respect to the film normal direction. Measured at 11 points by making light of wavelength λ nm incident from each tilted direction in 10 degree steps, and based on the measured retardation value, assumed value of average refractive index, and input film thickness value KOBRA 21ADH or WR is calculated.
In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used.
Moreover, about the thing whose average refractive index value is not known, it can measure with an Abbe refractometer. The average refractive index values of the main optical compensation films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49) Polystyrene (1.59). The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

(Optical compensation film)
The optical compensation film of the present invention aligns a liquid crystal layer functioning as a first optical anisotropic layer, a support functioning as a second optical anisotropic layer, and liquid crystal molecules constituting the liquid crystal layer. The support, the alignment film, and the liquid crystal layer are laminated in this order.

  The optical compensation film of the present invention can be used alone for a member of a liquid crystal display device or the like, but can also be integrated with a polarizing plate and incorporated into a liquid crystal display device as one member constituting the polarizing plate. The polarizing plate including the optical compensation film of the present invention as a constituent element not only has a polarizing function, but also contributes to an increase in the viewing angle of the liquid crystal display device. Further, the optical compensation film of the present invention may be used as a protective film for the polarizing film, and such a configuration contributes to the thinning of the liquid crystal display device.

<Support (second optically anisotropic layer)>
The support that the optical compensation film of the present invention has is the “second optically anisotropic layer” in the present invention, and is preferably glass or a transparent polymer film. The support preferably has a light transmittance of 80% or more.
Further, the support preferably has a retardation value Rth in the thickness direction measured with light having a wavelength of 550 nm in the range of 10 to 300 nm, and more preferably 30 to 200 nm.
The in-plane retardation value Re is preferably 1 to 100 nm, and more preferably 5 to 60 nm.

Examples of the polymer constituting the polymer film include cellulose esters (eg, cellulose acetate, cellulose diacetate), norbornene-based polymers, and polymethyl methacrylate. A commercially available polymer (for norbornene polymers, both Arton and Zeonex are trade names)) may be used.
Of these, cellulose ester is preferable, and lower fatty acid ester of cellulose is more preferable. Lower fatty acid means a fatty acid having 6 or less carbon atoms. In particular, the number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.

In order to adjust the retardation of cellulose acetate to the above-mentioned preferable range, a method of applying an external force such as stretching is common. Further, a retardation increasing agent may be added to adjust the optical anisotropy.
The retardation increasing agent is preferably an aromatic compound having at least two aromatic rings. The aromatic compound is preferably used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the polymer. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring.
The retardation increasing agent is described in European Patent Application No. 0911656, JP-A Nos. 2000-1111914 and 2000-275434.

Even in the case of conventionally known polymers such as polycarbonate and polysulfone that easily develop birefringence, the birefringence expression can be controlled by modifying the molecule as described in WO00 / 26705. For example, it can be used for the optical compensation sheet of the present invention.
When using the optical compensation film of the present invention for a polarizing plate protective film or a retardation film, it is preferable to use cellulose acetate having an acetylation degree of 55.0 to 62.5% as the polymer film. The acetylation degree is more preferably 57.0 to 62.0%.

The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation is determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (testing method for cellulose acetate, etc.).
The viscosity average degree of polymerization (DP) of cellulose acetate is preferably 250 or more, and more preferably 290 or more. Cellulose acetate preferably has a narrow molecular weight distribution of Mw / Mn (Mw is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mw / Mn is preferably 1.0 to 1.7, more preferably 1.0 to 1.65, and particularly preferably 1.0 to 1.6. preferable.

In cellulose acetate, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted, but the substitution degree at the 6-position tends to be small. In the polymer film used in the present invention, it is preferable that the degree of substitution at the 6-position of cellulose is the same or greater than that at the 2- and 3-positions.
The ratio of the substitution degree at the 6-position to the total substitution degree at the 2-position, the 3-position, and the 6-position is preferably 30 to 40%, more preferably 31 to 40%, and more preferably 32 to 40%. It is particularly preferred. The substitution degree at the 6-position is preferably 0.88 or more.
The degree of substitution at each position can be measured by NMR.
Cellulose acetate having a high degree of substitution at the 6-position is described in Synthesis Example 1 described in Paragraph Nos. 0043 to 0044, Synthesis Example 2 described in Paragraph Nos. 0048 to 0049, and Paragraph Nos. 0051 to 0052. It can be synthesized with reference to the method of Synthesis Example 3.

<First optically anisotropic layer>
The first optically anisotropic layer is preferably designed so as to compensate for the liquid crystalline compound in the liquid crystal cell in the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in black display varies depending on the mode of the liquid crystal display device. Regarding the alignment state of the liquid crystal compound in this liquid crystal cell, IDW'00, FMC7-2 p. 411-414 and the like.
The first optically anisotropic layer is formed directly from the liquid crystalline compound on the support or from the liquid crystalline compound via an alignment film. The alignment film preferably has a thickness of 10 μm or less.
The slow axis of the first optical anisotropic layer constituting the optical compensation film of the present invention is not orthogonal and parallel to the slow angle of the slow axis of the support (second optical anisotropic layer). The following mathematical formula (1) is satisfied.
2 <Re (40) / Re (−40) <7 Equation (1)
In the mathematical formula (1), Re (40) is measured from a direction inclined by (+) 40 degrees with respect to the slow axis of the first optically anisotropic layer as an axis from the normal line of the optical compensation film. Retardation value of the first optically anisotropic layer is represented, Re (−40) is −40 degrees from the normal line of the optical compensation film with the slow axis of the first optically anisotropic layer as an axis. It represents the retardation value of the first optically anisotropic layer measured from the inclined direction. However, Re (40)> Re (−40).
In addition, the retardation value Re (0) measured from the normal direction of the first optically anisotropic layer satisfies the following formula (2).
35 <Re (0) <60 ......... Formula (2)
The liquid crystalline compound used for the first optically anisotropic layer includes a rod-like liquid crystalline compound and a discotic liquid crystalline compound. The rod-like liquid crystal compound and the discotic liquid crystal compound may be a high-molecular liquid crystal or a low-molecular liquid crystal, and further include those in which the low-molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity. A 1st optically anisotropic layer is formed by apply | coating the coating liquid containing a liquid crystalline compound and a polymeric initiator as needed, and arbitrary components on an alignment film. A preferred example of the alignment film of the present invention is described in JP-A-8-338913.
Further, the thickness (film thickness) of the first optically anisotropic layer is preferably 1.7 μm or less.

[Bar-shaped liquid crystalline compound]
Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.
The rod-like liquid crystalline compound includes a metal complex. Moreover, the liquid crystal polymer which contains a rod-shaped liquid crystalline compound in a repeating unit can also be used as the rod-shaped liquid crystalline compound of the present invention. In other words, the rod-like liquid crystalline compound may be bonded to a (liquid crystal) polymer.
As for rod-like liquid crystalline compounds, for example, Quarterly Chemical Review Vol. 22, Chapter 4 of Liquid Crystal Chemistry (1994), Chapter of Chemical Society of Japan, Chapter 7, Chapter 11 and Liquid Crystal Device Handbook Japan Society for the Promotion of Science, 142nd Committee The one described in Chapter 3 of the edition can be adopted.
The birefringence of the rod-like liquid crystalline compound is preferably in the range of 0.001 to 0.7.

  The rod-like liquid crystalline compound preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and particularly preferably an ethylenically unsaturated polymerizable group.

[Discotic liquid crystalline compounds]
Examples of discotic liquid crystalline compounds include C.I. Benzene derivatives described in a research report of Destrade et al. (Mol. Cryst. 71, 111 (1981)), C.I. Destrode et al. (Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990)). The cyclohexane derivatives described in the research report of Kohne et al. (Angew. Chem. 96, 70 (1984)) and M.M. Lehn et al. (JCS, Chem. Commun., 1794 (1985)), J.C. Azacrown-type and phenylacetylene-type macrocycles described in the research report of Zhang et al. (J. Am. Chem. Soc. 116, 2655 (1994)) are included.

The discotic liquid crystalline compound also includes a compound having a structure in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation.
The optically anisotropic layer formed from the discotic liquid crystalline compound does not necessarily require that the compound finally contained in the optically anisotropic layer is a discotic liquid crystalline compound. Also included are compounds having a group that reacts with heat or light and, as a result, polymerized or crosslinked by reaction with heat or light, resulting in a high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. Moreover, about superposition | polymerization of a discotic liquid crystalline compound, Unexamined-Japanese-Patent No. 8-27284 has description.

  In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Accordingly, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (1).

(In General Formula (1), D is a discotic core, L is a divalent linking group, Q is a polymerizable group, and n is an integer of 4 to 12.)

  An example of the disk-shaped core (D) 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).

In the general formula (1), the divalent linking group (L) is a group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. It is preferably a divalent linking group selected more.
The divalent linking group (L) is a divalent linking in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O-, and S- are combined. More preferably, it is a group.
The divalent linking group (L) is particularly preferably a divalent linking group obtained by combining at least two divalent groups selected from the group consisting of an alkylene 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, and the arylene group preferably has 6 to 10 carbon atoms. .

As examples of the divalent linking group (L), (L1 to L25) 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. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl 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-O-CO-
L20: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L21: -S-AL-
L22: -S-AL-O-
L23: -S-AL-O-CO-
L24: -S-AL-S-AL-
L25: -S-AR-AL-

  The polymerizable group (Q) of the general formula (1) is determined according to the type of polymerization reaction. Examples of the polymerizable group (Q) are shown below.

The polymerizable group (Q) is preferably an unsaturated polymerizable group (Q1, Q2, Q3, Q7, Q8, Q15, Q16, Q17) or an epoxy group (Q6, Q18). More preferably, it is particularly preferably an ethylenically unsaturated polymerizable group (Q1, Q7, Q8, Q15, Q16, Q17).
Moreover, in the said General formula (1), n is an integer of 4-12. A specific value of n is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and Q may differ, it is preferable that it is the same.

In the hybrid alignment, the angle between the major axis (disk surface) of the discotic liquid crystalline compound and the surface of the support, that is, the inclination angle is in the direction of the depth of the optically anisotropic layer (that is, perpendicular to the transparent support). And it increases or decreases as the distance from the plane of the polarizing film increases. The angle preferably decreases with increasing distance.
In addition, as the change in inclination angle, continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, or intermittent change including increase and decrease are possible. . The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction.
Even if the inclination angle includes a region where the angle does not change, the inclination angle may be increased or decreased as a whole. Furthermore, it is preferable that the inclination angle changes continuously.

The average direction of the major axis (disk surface) of the discotic liquid crystalline compound (average of the major axis direction of each molecule) is generally selected by selecting the discotic liquid crystalline compound or the material of the alignment film, or selecting the rubbing treatment method. By doing so, it can be adjusted.
The major axis (disk surface) direction of the discotic liquid crystalline compound on the surface side (air side) is generally adjusted by selecting the type of additive used together with the discotic liquid crystalline compound or the discotic liquid crystalline compound. be able to.
Examples of the additive used together with the discotic liquid crystalline compound include a plasticizer, a surfactant, a polymerizable monomer and a polymer. The degree of change in the orientation direction of the major axis can also be adjusted by selecting liquid crystalline molecules and additives as described above.

The plasticizer, surfactant and polymerizable monomer used together with the discotic liquid crystalline compound are compatible with the discotic liquid crystalline compound, and can change the tilt angle of the discotic liquid crystalline compound or change the orientation. It is preferable not to inhibit. Among the additive components, addition of a polymerizable monomer (eg, a compound having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group) is preferable.
The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline compound. In addition, when a monomer having 4 or more polymerizable reactive functional groups is mixed and used, adhesion between the alignment film and the optically anisotropic layer can be improved.

The first optically anisotropic layer may contain a polymer together with the discotic liquid crystalline compound. The polymer preferably has a certain degree of compatibility with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound.
Examples of the polymer include cellulose ester.
Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate.
As described above, cellulose esters, particularly cellulose acetate butyrate, promotes the formation of domains as the amount added increases. Therefore, the amount of the polymer added is disco so as not to inhibit the orientation of the discotic liquid crystalline compound. It is preferably in the range of 0.1 to 2.0% by weight, more preferably in the range of 0.1 to 1.5% by weight, based on the tick liquid crystalline compound, and 0.1 to 1.0% by weight. % Is more preferable.
The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

-Fixing the alignment state of liquid crystal molecules-
The aligned liquid crystal molecules can be fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Among them, the photopolymerization reaction is preferable.
Examples of photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin compounds ( US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367), acridine, and Phenazine compounds (described in JP-A-60-105667 and US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,221,970) are included.

The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.5 to 5% by mass, based on the solid content of the coating solution.
It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules.
The irradiation energy ^is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5,000mJ / cm ^2, in a range of 100 to 800 mJ / cm ² Further preferred. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. A protective layer may be provided on the optically anisotropic layer.

[Fluoropolymer]
In order for the first optically anisotropic layer to satisfy the above formula (1), the first optically anisotropic layer contains a fluoroaliphatic represented by the following general formula (2) or general formula (3). A copolymer containing a repeating unit derived from a group-containing monomer (sometimes abbreviated as “fluorine polymer”) is contained. The fluorinated polymer is an acrylic resin or a methacrylic resin containing both a monomer represented by the following general formula (2) or general formula (3) and a repeating unit derived from the monomer represented by the general formula (4). It is preferable that the acrylic resin and the methacrylic resin are copolymerized with a vinyl monomer copolymerizable with these monomers.

  The fluoroaliphatic group in the fluoropolymer is derived from, for example, a fluoroaliphatic compound produced by either a telomerization method (also referred to as a telomer method), an oligomerization method (also referred to as an oligomer method), or electrolytic fluorination. It is preferred that Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorines Compounds”. II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995). The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (an example is shown in Scheme 1). )

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as [Scheme 2], and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as necessary, and used for the production of a fluoroaliphatic group-containing polymer. N in [Scheme2] represents a natural number.

  In the fluoropolymer of the present invention, a fluoroaliphatic group-containing monomer represented by the following general formula (2) or general formula (3) is preferably used.

In the general formula (2), _{R 1} represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or -N _{(R 2)} - a represents _{(R 2} is a hydrogen atom or an alkyl of 1 to 4 carbon atoms Represents a hydrogen atom or a methyl group.), Z represents a hydrogen atom or a fluorine atom, m represents an integer of 1 to 6, and n represents an integer of 2 to 4.

  X is preferably an oxygen atom, Z is preferably a hydrogen atom, m is preferably 1 or 2, n is preferably 3 or 4, and a mixture thereof may be used.

  In the general formula (3), A is a divalent (q = 1) or trivalent (q = 2) linking group selected from the following linking group group A, or 2 selected from the following linking group group A. It represents a divalent (q = 1) or trivalent (q = 2) linking group formed by combining two or more, and the linking groups may be bonded via an oxygen atom.

--Linking group A--
The linking group group _{A, -CH 2 -, - CH} 2 CH 2 -, - CH 2 CH 2 CH 2 -, - C 6 H 4 -, and _C 6 _{H 3} <and the like. However, the substitution position on the benzene ring may be any position.

  In the general formula (3), Z represents a hydrogen atom or a fluorine atom, p represents an integer of 3 to 8, and q represents 1 or 2.

  In the general formula (3), A preferably has the structure shown below.

  Z is preferably a fluorine atom, p is preferably 4 or 6, and a mixture thereof may be used.

  Specific examples of monomers that can be used in the production of the fluorine-based polymer that can be used in the present invention are listed below, but the present invention is not limited to the following specific examples.

  One aspect of the fluorine-based polymer that can be used in the present invention is a repeating unit derived from a monomer containing a repeating unit derived from a fluoroaliphatic group-containing monomer and a hydrophilic group represented by the following general formula (4). A copolymer having units.

In the general formula (4), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent. Q is a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof, an alkyl group, or a terminal is hydrogen. Represents a poly (alkyleneoxy) group which is an atom or an alkyl group. L represents an arbitrary group selected from the following linking group group L, or a divalent linking group formed by combining two or more thereof.

--Linking group L--
Examples of the linking group L include a single bond, —O—, —CO—, —NR ⁴ — (R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —. , —P (═O) (OR ⁵ ) — (R ⁵ represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.

In the general formula (4), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent selected from the substituent group exemplified below.

--Substituent group--
As the substituent group, an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, and an isopropyl group. , Tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like, alkenyl group (preferably having 2 to 20 carbon atoms, more preferably An alkenyl group having 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include a vinyl group, an aryl group, a 2-butenyl group, and a 3-pentenyl group, and an alkynyl group (preferably a carbon number). An alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as a propargyl group, A tinyl group), an aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as a phenyl group and p-methyl group). A phenyl group, a naphthyl group, etc.), an aralkyl group (preferably an aralkyl group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as a benzyl group, A phenethyl group, a 3-phenylpropyl group and the like), a substituted or unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably an amino group having 0 to 6 carbon atoms). And examples thereof include an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and an anilino group).

  In addition, as the substituent group, an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 10 carbon atoms, such as a methoxy group, An ethoxy group, a butoxy group, etc.), an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms. And an ethoxycarbonyl group), an acyloxy group (preferably an acyloxy group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms, such as an acetoxy group and a benzoyloxy group. Etc.), an acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms) Particularly preferred are acylamino groups having 2 to 10 carbon atoms, such as acetylamino group and benzoylamino group, and alkoxycarbonylamino groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, Particularly preferred are alkoxycarbonylamino groups having 2 to 12 carbon atoms, such as methoxycarbonylamino group, and aryloxycarbonylamino groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms). Particularly preferred is an aryloxycarbonylamino group having 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group, and a sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 1 carbon atoms). 16, particularly preferably a sulfonylamino group having 1 to 12 carbon atoms Yes, for example, a methanesulfonylamino group, a benzenesulfonylamino group, and the like), a sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably having 0 to 16 carbon atoms, and particularly preferably having 0 to 12 carbon atoms). For example, sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group, etc.), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). Particularly preferred is a carbamoyl group having 1 to 12 carbon atoms, and examples thereof include an unsubstituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, and a phenylcarbamoyl group.

In addition, as the substituent group, an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as a methylthio group, An ethylthio group), an arylthio group (preferably an arylthio group having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as a phenylthio group). ), A sulfonyl group (preferably a sulfonyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include a mesyl group and a tosyl group), sulfinyl Group (preferably a sulfinyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, For example, a methanesulfinyl group, a benzenesulfinyl group, etc.), a ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, , Unsubstituted ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). Phosphoric acid amide groups such as diethyl phosphoric acid amide group and phenylphosphoric acid amide group), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), Cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Terocyclic group (preferably a heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, oxygen atom, sulfur atom, etc., for example, imidazolyl Group, pyridyl group, quinolyl group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably A silyl group having 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group.
These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

In the general formula (4), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) It is preferably a group represented by LQ, more preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, and a hydrogen atom or carbon number. It is more preferably an alkyl group having 1 to 4, particularly preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, R ² and R ³ are hydrogen atoms, and R ¹ is a hydrogen atom or a methyl group. Most preferably it is.
Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent.
Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like. The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

In the general formula (4), L represents a divalent linking group selected from the above linking group group L, or a divalent linking group formed by combining two or more thereof.
In the linking group L, R ^{4 in} —NR ⁴ — represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, and is preferably a hydrogen atom or an alkyl group.
R ⁵ of —PO (OR ⁵ ) — represents an alkyl group, an aryl group or an aralkyl group, and is preferably an alkyl group. In the case where R ⁴ and R ⁵ represent an alkyl group, an aryl group or an aralkyl group, the number of carbon atoms is the same as that described in the “Substituent group”.
L preferably includes a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, an alkylene group, or an arylene group, and includes a single bond, —CO—, —O—. , —NR ⁴ —, an alkylene group, or an arylene group is more preferable, and a single bond is more preferable.
When L contains an alkylene group, 1-12 are preferable, as for carbon number of an alkylene group, 1-8 are more preferable, and 1-6 are still more preferable. Specific examples of particularly preferred alkylene groups include methylene, ethylene, trimethylene, tetrabutylene, hexamethylene groups and the like.
When L contains an arylene group, 6-24 are preferable, as for carbon number of an arylene group, 6-18 are more preferable, and 6-12 are still more preferable. Specific examples of particularly preferred arylene groups include phenylene and naphthalene groups.
When L contains a divalent linking group obtained by combining an alkylene group and an arylene group (that is, an aralkylene group), the carbon number of the aralkylene group is preferably 7 to 36, more preferably 7 to 26, and 7 to 16 Is more preferable. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group.
The group listed as L may have a suitable substituent. Examples of such a substituent include the same substituents as those described above as the substituents for R ^{1 to} R ³ .
Hereinafter, specific structures of L will be exemplified, but the present invention is not limited to these specific examples.

In the general formula (4), Q is a carboxyl group, a salt of a carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, Trimethylbenzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming the salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups ( Examples of the cation forming the salt are the same as those described for the above carboxyl group), an alkyl group (having 1 to 18 carbon atoms), or a poly (alkyleneoxy) group whose terminal is a hydrogen atom or an alkyl group.
Poly (alkyleneoxy) groups can be represented by (OR) x-G, R is an alkylene group having 2 to 4 carbon atoms, such as _{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, It is preferably —CH (CH ₃ ) CH ₂ — or —CH (CH ₃ ) CH (CH ₃ ) —.
G is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and is preferably a hydrogen atom or a methyl group.
x represents a natural number, but the oxyalkylene units in the poly (oxyalkylene) group may be the same as in poly (oxypropylene), and two or more different oxyalkylenes are randomly distributed. It may be a linear or branched oxypropylene or oxyethylene unit, or a linear or branched oxypropylene unit block and an oxyethylene unit block. May be.
The poly (oxyalkylene) chain may include those linked by one or more linking groups (for example, -CONH-Ph-NHCO-, -S-, etc .: Ph represents a phenylene group). When the linking group has a valence of 3 or more, a branched oxyalkylene unit is obtained.
When a copolymer containing a polymer unit having a poly (oxyalkylene) group is used in the present invention, the molecular weight of the poly (oxyalkylene) group is suitably from 80 to 3,000, and from 250 to 3,000. Is more preferable.
Poly (oxyalkylene) acrylates and methacrylates are commercially available hydroxypoly (oxyalkylene) materials such as “Pluronic” (Pluronic (Asahi Denka Kogyo Co., Ltd.), Adeka Polyether (Asahi Denka Kogyo Co., Ltd.) "Carbowax (Carbowax (Glyco-Products))", "Triton" (Toriton (Rohm and Haas) (Rohm and Haas)) and PEG (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting them with acrylic acid, methacrylic acid, acrylic chloride, methacryl chloride or acrylic anhydride, etc. Separately, poly (oxyalkylene) diacrylate produced by a known method is used. You can also.

  Although the specific example of the monomer corresponding to the said General formula (4) which can be utilized for manufacture of the fluorine-type polymer which can be used for this invention is given below, this invention is not restrict | limited at all by the following specific examples. The poly (alkyleneoxy) group is often a mixture of those having different degrees of polymerization x, and even in the compounds shown as specific examples, the degree of polymerization is expressed by an integer close to the average of the degrees of polymerization.

  The fluoropolymer may contain one type of repeating unit represented by the general formula (4), or may contain two or more types. Moreover, the said fluorine-type polymer may have 1 type (s) or 2 or more types of repeating units other than said each repeating unit. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. Hereinafter, specific examples of monomers for deriving other repeating units will be given. The fluoropolymer may contain a repeating unit derived from one or more monomers selected from the monomer group consisting of the following (1) to (8).

--- Monomer group--
(1) Alkenes ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-eicocene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3,3,3- Trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc.

(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro -1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2- Trichloro-1,3-butadiene, 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane, etc.

(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate , Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (polyoxyethylene added mole number: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such

(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxypolyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate , Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc.

(3c) Unsaturated polycarboxylic acid diesters Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc.

(3d) Amides of α, β-unsaturated carboxylic acid N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tert-butylacrylamide, N-tert-octylmethacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide, etc.

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc.

(5) Styrene and derivatives thereof Styrene, vinyl toluene, ethyl styrene, p-tert-butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p- Hydroxymethylstyrene, p-acetoxystyrene, etc.

(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl phenylacetate, etc.

(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc.

(8) Other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline, etc.

  As the monomer for deriving another repeating unit, a monomer represented by the following general formula (5) is preferably used.

In the above general formula (5), R ⁶ represents a hydrogen atom or a methyl group, Z represents a divalent linking group, R ⁷ represents a straight chain having 1 to 20 carbon atoms, which may have a substituent, Represents a branched or cyclic alkyl group. As the divalent linking group represented by Z, an oxygen atom, a sulfur atom, or —N (R ⁵ ) — is preferable. Here, R ⁵ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, or butyl. R ⁵ is more preferably a hydrogen atom or methyl. Z is particularly preferably an oxygen atom, —NH—, or —N (CH ₃ ) —.

In the general formula (5), the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms represented by R ⁷ may be a methyl group, ethyl group, propyl group, which may be linear or branched, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, eicosanyl, etc., cyclopentyl, cyclohexyl Monocyclic cycloalkyl groups such as cycloheptyl group and bicycloheptyl group, bicyclononyl group, bicyclodecyl group, tricyclodecyl group, tricycloundecyl group, tetracyclododecyl group, adamantyl group, norbornyl group, tetracyclodecyl group A polycyclic cycloalkyl group such as is preferably used.

Examples of the substituent of the alkyl group represented by R ⁷ include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylcarbonyloxy group, a carboxyl group, an alkyl ether group, an aryl ether group, a fluorine atom, a chlorine atom, and a bromine atom. Examples include, but are not limited to, a halogen atom, a nitro group, a cyano group, and an amino group.

  The monomer represented by the general formula (5) is particularly preferably alkyl (meth) acrylate or poly (alkyleneoxy) (meth) acrylate.

  Here, although the specific example of the monomer shown by the said General formula (5) is shown next, this invention is not restrict | limited at all by the following specific examples.

  The fluorine-based polymer used in the present invention is preferably contained in at least two kinds in the first optically anisotropic layer. By containing at least two kinds, it becomes possible to independently improve the unevenness and control the liquid crystalline compound, and it is possible to achieve both planarity and viewing angle characteristics.

  In the fluoropolymer, the amount of the fluoroaliphatic group-containing monomer is preferably 5% by mass or more, more preferably 10% by mass or more, and more preferably 30% by mass or more of the total amount of constituent monomers of the polymer. Is more preferable.

  The mass average molecular weight of the fluoropolymer used in the present invention is preferably 1,000 or more and 1,000,000 or less, more preferably 1,000 or more and 500,000 or less, and 1,000 or more and 100 or 100. More preferably, it is 1,000 or less. The mass average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).

The polymerization method of the fluorine-based polymer is not particularly limited, and for example, a polymerization method using a vinyl group such as cationic polymerization, radical polymerization, or anionic polymerization can be employed. Polymerization is particularly preferable in that it can be used for general purposes.
As the polymerization initiator for radical polymerization, known compounds such as radical thermal polymerization initiators and radical photopolymerization initiators can be used, and it is particularly preferable to use radical thermal polymerization initiators.
Here, the radical thermal polymerization initiator is a compound that generates radicals by heating to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include diacyl peroxide (acetyl peroxide, benzoyl peroxide, etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), hydroperoxide (hydrogen peroxide, tert. -Butyl hydroxide, cumene hydroperoxide, etc.), dialkyl peroxide (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyesters (tert-butyl peroxyacetate, tert) -Butyl peroxypivalate, etc.), azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, sodium persulfate) And potassium persulfate) and the like. Such radical thermal polymerization initiators can be used singly or in combination of two or more.

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, and the like can be adopted. The solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described, for example, in “Polymer Science Experimental Method” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).

  An organic solvent is used for solution polymerization. These organic solvents can be arbitrarily selected as long as the objects and effects of the present invention are not impaired. These organic solvents are usually organic compounds having boiling points under atmospheric pressure in the range of 50 to 200 ° C., and organic compounds that uniformly dissolve each component are preferred. Examples of preferred organic solvents are: alcohols such as isopropanol and butanol; ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate and acetic acid And esters such as butyl, amyl acetate, and γ-butyrolactone; and aromatic hydrocarbons such as benzene, toluene, and xylene. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Also, the solution polymerization conditions are not particularly limited, but for example, it is preferable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 30 hours. Furthermore, in order not to deactivate the generated radicals, it is preferable to perform an inert gas purge not only during solution polymerization but also before the start of solution polymerization. Usually, nitrogen gas is suitably used as the inert gas.

In order to obtain the fluoropolymer in a preferable molecular weight range, a radical polymerization method using a chain transfer agent is particularly effective. As chain transfer agents, mercaptans (for example, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol, etc.), polyhalogenated alkyls (for example, carbon tetrachloride, chloroform, etc.) , 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, preferably carbon These are mercaptans of 4-16.
The amount of these chain transfer agents used is remarkably influenced by the activity of the chain transfer agent, the combination of the monomers, the polymerization conditions and the like, and must be precisely controlled. It is preferably about 01 to 50 mol%, more preferably 0.05 to 30 mol%, and more preferably 0.08 to 25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization should be controlled in the polymerization process, and the addition method is not particularly limited. It may be added after being dissolved in the monomer, or it may be added separately from the monomer.

Specific examples of the fluoroaliphatic group-containing copolymer preferably used in the present invention as the fluorine-based polymer are shown below, but the present invention is not limited to these specific examples.
Here, the numerical value in a formula is a mass percentage which shows the composition ratio of each monomer, respectively, and Mw is the mass mean molecular weight of PS conversion measured by GPC. Numerical values such as a, b, c, and d represent mass ratios.

  The fluoropolymer used in the present invention can be produced by a publicly known and commonly used method. For example, it can be produced by adding a general-purpose radical polymerization initiator to an organic solvent containing the above-described monomer having a fluoroaliphatic group, a monomer having a hydrogen bonding group, and the like, and polymerizing the mixture. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition.

  The content of the fluoropolymer is preferably 0.005 to 8% by mass, and 0.01 to 5% by mass in the composition (a composition excluding the solvent in the case of a coating solution). Is more preferable, and it is still more preferable that it is 0.05-2.5 mass%. When the addition amount of the fluoropolymer is within the above range, the effect can be sufficiently exerted, the coating film can be sufficiently dried, and the performance as an optical compensation film (for example, uniformity of retardation) is further improved. it can.

The first optically anisotropic layer is prepared by preparing a coating solution containing at least one liquid crystalline compound and, optionally, an additive such as a polymerizable initiator and a fluorine-based polymer, and applying the coating solution to the alignment film surface. It can be formed by coating and drying.
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), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among these, alkyl halides and ketones are preferable. Two or more organic solvents may be used in combination.
When producing an optical compensation film with high uniformity, the surface tension of the coating solution is preferably 25 mN / m or less, and more preferably 22 mN / m or less.

  The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

(Polarizer)
Next, a polarizing plate having the optical compensation film of the present invention as a protective film will be described.
The optical compensation film of the present invention can remarkably exhibit its function by being bonded to a polarizing plate or used as a protective film for protecting a polarizing film (polarizer) of a polarizing plate.

<Polarizing film>
The polarizing film usable for the polarizing plate of the present invention is preferably a coating type polarizing film represented by Optiva, or a polarizing film comprising a binder and iodine or a dichroic dye.
Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal.

A general-purpose polarizer can be prepared, for example, by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing the iodine or dichroic dye to penetrate into the binder. it can.
In general-purpose polarizing films, iodine or dichroic dye is distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time.
As described above, the lower limit of the binder thickness is preferably 10 μm. On the other hand, the upper limit of the thickness is not particularly limited, but the thinner the better, from the viewpoint of the light leakage phenomenon that occurs when the polarizing plate is used in a liquid crystal display device. Currently, it is preferably not more than a general-purpose polarizing plate (about 30 μm), preferably not more than 25 μm, and more preferably not more than 20 μm. When it is 20 μm or less, the light leakage phenomenon is not observed in a 17-inch liquid crystal display device.

The binder of the polarizing film may be cross-linked. As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change.
Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent. It can be formed by cross-linking between binders by introducing a bonding group derived from the cross-linking agent between binders using a cross-linking agent which is a compound having high reaction activity.
Crosslinking is generally carried out by applying a coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the cross-linking treatment may be performed at any stage until the final polarizing plate is obtained.

  As the binder for the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of polymers include polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, polystyrene, gelatin, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-methylolacrylamide), polyvinyltoluene, chlorosulfonated polyethylene, nitrocellulose, chlorinated Polyolefin (eg, polyvinyl chloride), polyester, polyimide, polyvinyl acetate, polyethylene, carboxymethyl cellulose, polypropylene, polycarbonate and copolymers thereof (eg, acrylic acid / methacrylic acid polymer, styrene / maleimide polymer, styrene / vinyl) Toluene polymer, vinyl acetate / vinyl chloride polymer, ethylene / vinyl acetate polymer). Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are particularly preferred. .

The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and particularly preferably 95 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5,000.
Modified polyvinyl alcohol is obtained by introducing a modifying group into polyvinyl alcohol by copolymerization modification, chain transfer modification or block polymerization modification.
In the copolymerization modification, —COONa, —Si (OH) ₃ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO—, —SO ₃ Na, —C ₁₂ H ₂₅ may be introduced as a modifying group. it can.
In chain transfer modification, —COONa, —SH, or —SC ₁₂ H ₂₅ can be introduced as a modifying group.
The degree of polymerization of the modified polyvinyl alcohol is preferably 100 to 3,000. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509, and JP-A-9-316127.
Unmodified polyvinyl alcohol and alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% are particularly preferred.
Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

When a large amount of the crosslinking agent for the binder is added, the heat and humidity resistance of the polarizing film can be improved. However, when 50 mass% or more of a crosslinking agent is added to the binder, the orientation of iodine or the dichroic dye is lowered. 0.1-20 mass% is preferable with respect to a binder, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is still more preferable.
The binder contains some crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less in the binder. When the crosslinking agent is contained in the binder layer in an amount exceeding 1.0% by mass, there may be a problem in durability. That is, when a polarizing film having a large amount of residual crosslinking agent is incorporated in a liquid crystal display device and used for a long time or left in a high-temperature and high-humidity atmosphere for a long time, the degree of polarization may decrease.
The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl).
Examples of dichroic dyes include C.I. I. Direct Yellow 12, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Direct Violet 48, C.I. I. Direct Blue 67, C.I. I. Direct Blue 90, C.I. I. Direct Green 59, C.I. I. Acid Red 37 is included.
As for the dichroic dyes, those described in JP-A-1-161202, 1-172906, 1-172907, 1-183602, 1-248105, 1-265205, 7-261024 are used. There are descriptions in each publication. The dichroic dye is used as a free acid or an alkali metal salt, ammonium salt or amine salt. By blending two or more kinds of dichroic dyes, polarizing films having various hues can be produced. A polarizing film using a compound (pigment) that exhibits a black color when the polarization axes are orthogonal to each other, or a polarizing film or a polarizing plate in which various dichroic molecules are blended so as to exhibit a black color, both with a single plate transmittance and a polarization rate It is excellent and preferable.

In order to increase the contrast ratio of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher and the degree of polarization is preferably higher.
The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and in the range of 40 to 50% in the light having a wavelength of 550 nm (of the polarizing plate). It is particularly preferable that the maximum value of the single plate transmittance is 50%.
The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and particularly preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  It is also possible to dispose the polarizing film and the optically anisotropic layer, or the polarizing film and the alignment film via an adhesive. As the adhesive, a polyvinyl alcohol resin (including a modified polyvinyl alcohol with an acetoacetyl group, a sulfonic acid group, a carboxyl group, or an oxyalkylene group) or an aqueous boron compound solution can be used. Of these, polyvinyl alcohol resins are preferred. The thickness of the adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and more preferably in the range of 0.05 to 5 μm.

<Manufacture of polarizing plate>
From the viewpoint of yield, the polarizing film is stretched at an angle of 10 to 80 degrees with respect to the longitudinal direction (MD direction) of the polarizing film (stretching method) or rubbed (rubbing method). It is preferable to dye with a dichroic dye. The tilt angle is preferably stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell.
A normal inclination angle is 45 degrees. Recently, however, devices that are not necessarily 45 degrees have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times.
The stretching step may be performed in several steps including oblique stretching. By dividing into several times, it is possible to stretch more uniformly even at high magnification. Before the oblique stretching, a slight stretching (a degree to prevent shrinkage in the width direction) may be performed horizontally or vertically.
Stretching can be performed by performing tenter stretching in biaxial stretching in different steps. The biaxial stretching is the same as the stretching method performed in normal film formation.
In biaxial stretching, stretching is performed at different speeds on the left and right, so that the thickness of the binder film before stretching needs to be different on the left and right. In casting film formation, the flow rate of the binder solution can be differentiated between the left and right sides by tapering the die.
As described above, a binder film that is obliquely stretched by 10 to 80 degrees with respect to the MD direction of the polarizing film is produced.

In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, orientation is obtained by rubbing the surface of the film in a certain direction using paper, gauze, felt, rubber, nylon, or polyester fiber.
Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average. At this time, it is preferable to carry out using a rubbing roll whose roundness, cylindricity, and runout (eccentricity) are all 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 degrees. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 degrees or more.
When rubbing a long film, the film is preferably transported at a speed of 1 to 100 m / min in a constant tension state by a transport device. The rubbing roll is preferably rotatable in the horizontal direction with respect to the film traveling direction for setting an arbitrary rubbing angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 degrees. When used in a liquid crystal display device, 40 to 50 degrees is preferable. 45 degrees is particularly preferable.
It is preferable to dispose a polymer film (arrangement of optically anisotropic layer / polarizing film / polymer film) on the surface of the polarizing film opposite to the optically anisotropic layer.

(Liquid crystal display device)
The optical compensation film and polarizing plate of the present invention can be used for liquid crystal display devices of various modes.
As shown in FIG. 1, the liquid crystal display device of the present invention is manufactured by combining a liquid crystal cell 10 and two elliptically polarizing plates installed so as to sandwich the liquid crystal cell 10.
In the elliptically polarizing plate, the first optical anisotropic layer 31A (31B) is formed on the second optical anisotropic layer 33A (33B) via an alignment film (not shown), and the polarizing film 34A ( 34B) is provided with the first optically anisotropic layer 31A (31B). It is preferable that a protective film is provided on the other surface of the polarizing film 34A (34B).
The elliptically polarizing plate is installed so that the first optically anisotropic layer 31 </ b> A (31 </ b> B) faces the liquid crystal cell 10. At this time, the rubbing direction RD2 (RD3) of the liquid crystal cell 10 and the rubbing direction RD1 (RD4) of the first optical anisotropic layer 31A (31B) opposed thereto are arranged to be antiparallel.
The in-plane slow axis of the first optically anisotropic layer 31A (31B) is orthogonal to and parallel to the in-plane slow axis SA1 (SA2) of the second optically anisotropic layer 33A (33B). And 45 ° in the present invention.
Hereinafter, preferred forms of the optically anisotropic layer in each liquid crystal mode will be described.

<TN mode liquid crystal display device>
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents.
The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which a rod-like liquid crystalline molecule rises at the center of the cell and the rod-like liquid crystalline compound lies in the vicinity of the cell substrate.

The rod-like liquid crystalline compound in the center of the cell is compensated with a discotic liquid crystalline compound of the homeotropic orientation (horizontal orientation in which the disk surface is lying) or a (transparent) support, and the rod-like liquid crystalline property in the vicinity of the cell substrate The compound can be compensated with a discotic liquid crystalline compound having a hybrid alignment (an alignment in which the inclination of the major axis changes with the distance from the polarizing film).
In addition, the rod-like liquid crystalline compound at the center of the cell is compensated with a rod-like liquid crystalline compound having a homogeneous orientation (horizontal orientation in which the major axis lies) or a (transparent) support, and the rod-like liquid crystalline property in the vicinity of the cell substrate The compound can be compensated with a discotic liquid crystalline compound having a hybrid alignment.

The homeotropic alignment liquid crystal compound is aligned in a state where the angle between the average alignment direction of the major axis of the liquid crystal compound and the plane of the polarizing film is 85 to 95 degrees.
The liquid crystal compound of homogeneous alignment is aligned with the angle between the average alignment direction of the major axis of the liquid crystal compound and the plane of the polarizing film being less than 5 degrees.
In the hybrid alignment liquid crystal compound, the angle between the long axis average alignment direction of the liquid crystal compound and the plane of the polarizing film is preferably 15 degrees or more, and more preferably 15 to 85 degrees.

(Transparent) Optically anisotropic layer in which support or discotic liquid crystalline compound is homeotropically oriented, optically anisotropic layer in which rod-like liquid crystalline compound is homogeneously oriented, and also homeotropically oriented discotic The optically anisotropic layer comprising a mixture of a liquid crystal compound and a homogeneously oriented rod-like liquid crystal compound has a thickness direction retardation value Rth of 40 to 200 nm and an in-plane direction retardation value Re of 0 to 70 nm. It is preferable.
Regarding the discotic liquid crystal compound layer having homeotropic alignment (horizontal alignment) and the rod-like liquid crystal compound layer having homogeneous alignment (horizontal alignment), Japanese Patent Laid-Open Nos. 12-304931 and 12-304932 describe them. Are listed. The discotic liquid crystal compound layer having a hybrid orientation is described in JP-A-8-50206.

<OCB mode liquid crystal display device>
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which a rod-like liquid crystal compound is aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. Liquid crystal display devices using a bend alignment mode liquid crystal cell are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal compounds are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode.
Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystal compound rises at the center of the cell and the rod-like liquid crystal compound lies in the vicinity of the cell substrate. .

  Since the TN mode and the alignment of the liquid crystal are the same in black display, the preferred mode is the same for the TN mode. However, since the OCB mode has a larger range in which the liquid crystal compound has risen at the center of the cell than the TN mode, an optically anisotropic layer in which the discotic liquid crystal compound is homeotropically aligned or a rod-like liquid crystal It is necessary to slightly adjust the retardation value of the optically anisotropic layer in which the functional compound is homogeneously oriented. Specifically, the optically anisotropic layer in which the discotic liquid crystalline compound on the (transparent) support is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline compound is homogeneously oriented has a thickness of The longitudinal retardation value Rth is preferably 150 to 500 nm, and the in-plane retardation value Re is preferably 20 to 70 nm.

<VA mode liquid crystal display device>
In the VA mode liquid crystal cell, the rod-like liquid crystalline compound is aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which a rod-like liquid crystal compound is aligned substantially vertically when no voltage is applied, and is substantially horizontally aligned when a voltage is applied (Japanese Patent Laid-Open No. 2). 176625 (in Japanese Patent Publication No. 176625), and (2) a liquid crystal cell (SID97, Digest of tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (in MVA mode) for widening the viewing angle. ), (3) A liquid crystal cell in a mode (n-ASM mode) in which a rod-like liquid crystalline compound is substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary Collection 58-59 of the Japan Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).

  In the black display of the VA mode liquid crystal display device, most of the rod-like liquid crystalline compounds in the liquid crystal cell are in a standing state, so that the optically anisotropic layer in which the discotic liquid crystalline compounds are homeotropically aligned, Alternatively, the liquid crystalline compound is compensated by an optically anisotropic layer in which the rod-like liquid crystalline compound is homogeneously oriented, and separately, the rod-like liquid crystalline compound is homogeneously oriented, and the average orientation direction of the major axis of the rod-like liquid crystalline compound and the polarizing film It is preferable to compensate the viewing angle dependency of the polarizing plate with an optically anisotropic layer having an angle with respect to the transmission axis direction of less than 5 degrees.

  The (transparent) support or the optically anisotropic layer in which the discotic liquid crystalline compound is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline compound is homogeneously oriented has a thickness direction retardation value Rth. Is preferably 150 to 500 nm, and the in-plane retardation value Re is preferably 20 to 70 nm.

<Other liquid crystal display devices>
The ECB mode and STN mode liquid crystal display devices can be optically compensated in the same way as described above.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

(Example 1)
<Preparation of cellulose acetate solution>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

[Cellulose acetate solution composition]
Cellulose acetate with an acetylation degree of 60.9% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol ( Second solvent) 45 parts by mass
Dye (manufactured by Sumika Finechem Co., Ltd., 360FP) 0.0009 parts by mass

Into another mixing tank, 16 parts by mass of the retardation increasing agent represented by the following general formula (6), 80 parts by mass of methylene chloride, and 20 parts by mass of methanol are added and stirred while heating to obtain a retardation increasing agent solution. Prepared.
The dope was prepared by mixing 456.7 parts by mass of the cellulose acetate solution having the above composition with 40.6 parts by mass of the retardation increasing agent solution and 0.15 parts by mass of silica fine particles (R972, manufactured by Irosil) and stirring sufficiently. .
The addition amount of the retardation increasing agent was 5.6 parts by mass with respect to 100 parts by mass of cellulose acetate. Moreover, the addition amount of silica fine particles was 0.15 mass part with respect to 100 mass parts of cellulose acetate.

<Production of second optically anisotropic layer (support)>
The obtained dope was cast using a casting machine having a band having a width of 2 m and a length of 65 m. After the film surface temperature on the band reached 40 ° C., it was dried for 1 minute, peeled off, and then stretched 28% in the width direction using a tenter with a drying air of 140 ° C. Then, it dried for 20 minutes with 135 degreeC dry air, and the 2nd optically anisotropic layer whose residual solvent amount is 0.3 mass% was manufactured. The width of the obtained second optically anisotropic layer was 1,340 mm and the thickness was 88 μm.
Moreover, it was 39 nm when the retardation value (Re) in wavelength 550nm was measured using the ellipsometer (M-150, JASCO Corporation make).

<Saponification treatment of second optically anisotropic layer>
A 1.0 N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 69.2 parts / 15 parts by weight / 15.8 parts by weight) is formed on the band surface side of the produced second optically anisotropic layer. 10 mL / m ² , and kept at about 40 ° C. for 30 seconds, scraped off the alkaline solution, washed with pure water, and removed water droplets with an air knife. Then, it dried at 100 degreeC for 15 second. In this way, only one surface of the second optically anisotropic layer was saponified.

<Formation of alignment film>
On one surface of the saponified second optically anisotropic layer, an alignment film coating solution having the following composition was applied at 31 mL / m ² with a # 18 wire bar coater, and then heated with 100 ° C. hot air for 120 seconds. Dried.
Next, a rubbing treatment was performed on the formed film in a direction of 45 ° with the stretching direction of the second optical anisotropic layer (substantially perpendicular to the slow axis).

[Alignment film coating solution composition]
Modified polyvinyl alcohol represented by the following general formula (7) 20 parts by mass Water 363 parts by mass Methanol 116 parts by mass Glutaraldehyde (crosslinking agent) 1 part by mass
Citrate ester (AS3 manufactured by Sankyo Chemical Co., Ltd.) 0.35 parts by mass

<Production of first optically anisotropic layer>
On the alignment film, a first optical anisotropic layer coating solution having the following composition is rotated at a speed of 78 m / min in the same direction as the film transport direction by rotating a # 3.0 wire bar at 20 m / min. The film was continuously applied to the surface of the alignment film of the roll film being conveyed in step (1). In the step of continuously heating from room temperature to 100 ° C., the solvent was dried, and then heated in a drying zone at 135 ° C. for about 120 seconds to align the discotic liquid crystalline compound.
Next, it is transported to a drying zone at 100 ° C., and irradiated with ultraviolet rays with an illuminance of 600 mW for 4 seconds by an ultraviolet irradiation device (ultraviolet lamp: output 160 W / cm, emission length 1.6 m), and the crosslinking reaction proceeds, A tick liquid crystalline compound was fixed in the orientation. Then, it was allowed to cool to room temperature and wound into a cylindrical shape to obtain a roll-shaped optical compensation film.

<Evaluation of optical properties of first optical anisotropic layer>
Using the ellipsometer (M-150, manufactured by JASCO Corporation), retardation values (Re (0), Re (40), Re (−40) at a wavelength of 550 nm were used for the produced first optically anisotropic layer. )) Was measured. As a result, Re (0) was 45.0 nm and Re (40) / Re (−40) was 3.64. Moreover, it was 1.17 micrometers when the thickness of the 1st optically anisotropic layer was measured. The results are shown in Table 1.
Here, the fluoroaliphatic group-containing polymer (1) and cellulose acetate butyrate described below are involved in the surface improvement of the first optically anisotropic layer, and the fluoroaliphatic group-containing polymer (2) is It is involved in adjusting the tilt angle of the liquid crystal molecules on the air interface side. The fluoroaliphatic group-containing polymer (1) and the fluoroaliphatic group-containing polymer (2) are preferably used in combination.

[First Optically Anisotropic Layer Coating Solution Composition]
Discotic liquid crystalline compound (1) represented by the following general formula (8) 41 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4 parts by mass Cellulose acetate butyrate (CAB551) 0.2, manufactured by Eastman Chemical Co., Ltd.) 0.34 parts by mass Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co., Ltd.) 0.11 parts by mass A fluoro aliphatic group-containing polymer represented by the following general formula (9) ( 1) 0.02 parts by mass Fluoroaliphatic group-containing polymer represented by the following general formula (10) (2) 0.23 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Corp.) 1.35 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by mass
100 parts by mass of methyl ethyl ketone

<Production of elliptically polarizing plate>
A polyvinyl alcohol (PVA) film having a thickness of 80 μm is dyed by immersing it in an aqueous iodine solution having an iodine concentration of 0.05% by mass at 30 ° C. for 60 seconds, and then in an aqueous boric acid solution having a boric acid concentration of 4% by mass. The film was vertically stretched to 5 times the original length while being immersed for 2 seconds, and then dried at 50 ° C. for 4 minutes to obtain a polarizing film having a thickness of 20 μm.
The optical compensation film was immersed in an aqueous sodium hydroxide solution at 55 ° C. at 1.5 mol / L, and then the sodium hydroxide was sufficiently washed away with water. Then, after being immersed in a diluted sulfuric acid aqueous solution at 35 ° C. for 1 minute at 0.005 mol / L, the diluted sulfuric acid aqueous solution was sufficiently washed away by immersion in water. Finally, the sample was thoroughly dried at 120 ° C.
The optical compensation film subjected to the saponification treatment as described above was combined with a commercially available cellulose acylate film that was also subjected to the saponification treatment, and bonded using a polyvinyl alcohol adhesive so as to sandwich the polarizing film, and the elliptically polarized light was bonded. I got a plate.
Here, Fujitac TF80UL (manufactured by Fuji Photo Film Co., Ltd.) was used as a commercially available cellulose acylate film. At this time, since the polarizing film and the protective films on both sides of the polarizing film are produced in the form of rolls, the longitudinal directions of the roll films are parallel to each other and are bonded together. Therefore, the longitudinal direction of the roll of the optical compensation film (the casting direction of the cellulose acylate film) and the polarizer absorption axis were parallel to each other.

<Production of bend alignment liquid crystal cell>
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The obtained two glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 4.1 μm. A bend-aligned liquid crystal cell was produced by injecting a liquid crystal compound having a Δn (550) of 0.1396 (Merck, ZLI1132) into the cell gap.

<Production of bend alignment mode liquid crystal display device>
A liquid crystal display device shown in FIG. 1 was produced by combining a liquid crystal cell and two elliptically polarizing plates. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel. In addition, the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer were arranged to form approximately 45 °.

<Evaluation of bend alignment mode liquid crystal display device>
The produced liquid crystal display device was placed on a backlight, and a voltage was applied to the bend alignment liquid crystal cell with a 55 Hz rectangular wave. While adjusting the voltage, a luminance meter (manufactured by TOPCON, BM-5) was used to measure the voltage at which the black luminance (front luminance) was minimized.
Next, similarly, using a luminance meter, the black luminance and white luminance (front luminance) at the center of the screen were measured, and the contrast was calculated. Furthermore, the viewing angle was measured using a measuring machine (EZ-CONTRAST). The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Example 2)
<Production of optical compensation film and evaluation of optical characteristics>
An optical compensation film was produced in the same manner as in Example 1 except that in the application of the first optically anisotropic layer coating solution in Example 1, the number of rotations of the wire bar was changed to 390 rpm.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel. In addition, the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer were arranged to form approximately 45 °.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Example 3)
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co., Ltd. and CAB531-1, manufactured by Eastman Chemical Co.) in the first optically anisotropic layer coating solution was not added, An optical compensation film was produced in the same manner as in Example 1 except that # 3.6 wire bar was used.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

Example 4
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, the addition amount of cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co.) in the first optically anisotropic layer coating solution was 0.68 parts by mass, and # 1.6 An optical compensation film was produced in the same manner as in Example 1 except that a wire bar was used.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Example 5)
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, the addition amount of cellulose acetate butyrate (CAB551-0.2, Eastman Chemical Co.) in the first optically anisotropic layer coating solution was 0.68 parts by mass, and # 2.7 An optical compensation film was produced in the same manner as in Example 1 except that a wire bar was used.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Example 6)
<Production of optical compensation film and evaluation of optical characteristics>
In the application of the first optically anisotropic layer coating solution in Example 1, a # 4.0 wire bar was used, and the optical speed was the same as in Example 1 except that the rotational speed was 639 rpm. A compensation film was prepared.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Example 7)
<Production of optical compensation film and evaluation of optical characteristics>
In the application of the first optically anisotropic layer coating solution in Example 3, a # 4.0 wire bar was used and the number of revolutions was changed to 568 revolutions / minute. A compensation film was prepared.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1. It should be noted that there was no unevenness on the entire surface of the liquid crystal display device, and it was uniform.

(Comparative Example 1)
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, the same as Example 1 except that the fluoroaliphatic group-containing polymer (1) and the fluoroaliphatic group-containing polymer (2) in the first optically anisotropic layer coating solution were not added. Thus, an optical compensation film was produced.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 2)
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, the fluoroaliphatic group-containing polymer (1), the fluoroaliphatic group-containing polymer (2), and cellulose acetate butyrate (CAB551-0.2, Optical compensation in the same manner as in Example 1 except that the addition amount of cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) was 0.45 parts by mass without adding Eastman Chemical Co., Ltd. A film was prepared.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 3)
<Production of optical compensation film and evaluation of optical characteristics>
In Example 1, the fluoroaliphatic group-containing polymer (1), the fluoroaliphatic group-containing polymer (2), and cellulose acetate butyrate (CAB551-0.2, Without addition of Eastman Chemical Co., Ltd., adding 0.45 parts by mass of cellulose acetate butyrate (CAB531-1, Eastman Chemical Co., Ltd.), and using a # 4.0 wire bar, rotating An optical compensation film was produced in the same manner as in Example 1 except that the number was changed to 497 rpm.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 4)
<Production of optical compensation film and evaluation of optical characteristics>
In Comparative Example 1, the addition amount of cellulose acetate butyrate (CAB551-0.2, Eastman Chemical Co.) was 1.13 parts by mass, and cellulose acetate butyrate (CAB531-1, Eastman Chemical Co., Ltd.) was added. An optical compensation film was prepared in the same manner as in Comparative Example 1 except that the amount was 0.45 parts by mass and that a # 1.2 wire bar was used.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 5)
<Production of optical compensation film and evaluation of optical characteristics>
An optical compensation film was produced in the same manner as in Comparative Example 1 except that the rotation speed of the wire bar was changed to 390 rpm in the application of the first optically anisotropic layer coating solution in Comparative Example 1.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 6)
<Production of optical compensation film and evaluation of optical characteristics>
An optical compensation film in the same manner as in Comparative Example 1 except that the # 4 wire bar was used and the number of rotations was 639 rpm in the application of the first optically anisotropic layer coating solution in Comparative Example 1. Was made.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

(Comparative Example 7)
<Production of optical compensation film and evaluation of optical characteristics>
An optical compensation film was produced in the same manner as in Comparative Example 4 except that a # 2.0 wire bar was used in the application of the first optically anisotropic layer coating solution in Comparative Example 4.
In the same manner as in Example 1, the retardation values (Re (0), Re (40), Re (-40)) at a wavelength of 550 nm and the thickness of the first optical anisotropic layer were measured. The results are shown in Table 1.

<Production of elliptically polarizing plate>
In the same manner as in Example 1, a polarizing film was prepared, and the obtained optical compensation film was saponified, and the polarizing film was sandwiched in combination with a commercially available cellulose acylate film that was also saponified. Bonding was performed using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate.

<Production of bend alignment liquid crystal cell>
A bend alignment liquid crystal cell was produced in the same manner as in Example 1.

<Production of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, a liquid crystal cell and an elliptically polarizing plate were combined to produce the liquid crystal display device shown in FIG. The arrangement of the liquid crystal cell and the two polarizing plates is such that the polarizing plate faces the first optical anisotropic layer and the substrate of the liquid crystal cell, and the rubbing direction of the liquid crystal cell and the first optical anisotropic facing it. The rubbing direction of the conductive layer was arranged to be antiparallel.

<Evaluation of bend alignment mode liquid crystal display device>
In the same manner as in Example 1, the voltage with the smallest black luminance (front luminance) was measured, the contrast was calculated, and the viewing angle was measured. The results are shown in Table 1.

As shown in Table 1, in the optical compensation films of Examples 1 to 7, the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer are neither orthogonal nor parallel. Since the formula (1): 2 <Re (40) / Re (−40) <7 and the formula (2): 35 <Re (0) <60 are satisfied, a polarizing plate including the optical compensation film is installed. The liquid crystal display device can effectively optically compensate OCB and ECB mode liquid crystal cells, prevent light leakage, and obtain good contrast.
In particular, in Examples 1 to 6, it is possible to further reduce the thickness (d) of the first optical anisotropic layer (d <1.7 μm) while preventing light leakage and obtaining good contrast. It was.
Further, in contrast to Example 4 using the # 1.6 wire bar, Example 5 using the # 2.7 wire bar has the same optical characteristics (Re (40) / Re (−40)). However, the contrast characteristics slightly decreased. In particular, the thickness (d) is increased with respect to Example 3 in the same manner (d> 1.7 μm). In Example 7, the front contrast characteristic is further lowered than the decrease in the front contrast characteristic of Example 5 with respect to Example 4 above. Results in a decline.
On the other hand, the optical compensation films of Comparative Examples 1 to 7 do not satisfy the formula (1): 2 <Re (40) / Re (−40) <7 and the formula (2): 35 <Re (0) <60. Therefore, the liquid crystal display device provided with the polarizing plate provided with the optical compensation film cannot effectively optically compensate the OCB and ECB mode liquid crystal cells, light leakage occurs, and the contrast is poor.
FIG. 2 is a graph showing the relationship between Re (40) and Re (−40) in the present invention. As shown in FIG. 2, Examples 1 to 7 showing the above-described effects are obtained by the formula (1): 2 <Re (40) / Re (−40) <7 and the formula (2): 35 <Re (0). It falls within the range defined by <60 (within the trapezoidal shape surrounded by a solid line in FIG. 2).

In particular, the optical compensation film and the polarizing plate of the present invention can be suitably subjected to optical compensation during black display by being installed in an OCB or ECB mode liquid crystal cell.
In particular, the liquid crystal display device of the present invention can optically compensate for OCB and ECB mode liquid crystal cells, prevent light leakage, and obtain good contrast, and can be used for cellular phones, personal computer monitors, televisions, and liquid crystal projectors. For example, it can be suitably used.

FIG. 1 is a schematic view showing the configuration of the liquid crystal display device of the present invention. FIG. 2 is a graph showing the relationship between Re (40) and Re (−40) in Examples 1 to 7 and Comparative Examples 1 to 7.

Explanation of symbols

10 Liquid crystal cell 31A, 31B First optical anisotropic layer 33A, 33B Second optical anisotropic layer 34A, 34B Polarizing film RD1, RD2, RD3, RD4 Rubbing direction SA1, SA2 In-plane slow axis TA1, TA2 In-plane transmission axis BL Backlight

Claims (8)

It has the 1st optically anisotropic layer formed from the composition containing a liquid crystalline compound, and the 2nd optically anisotropic layer, and the said 1st optically anisotropic layer is represented by following Numerical formula (1). An optical compensation film characterized in that the crossing angle between the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is not orthogonal or parallel.
2 <Re (40) / Re (−40) <7 Equation (1)
In the mathematical formula (1), Re (40) is measured from a direction inclined by (+) 40 degrees with respect to the slow axis of the first optically anisotropic layer as an axis from the normal line of the optical compensation film. Retardation value of the first optically anisotropic layer is represented, Re (−40) is −40 degrees from the normal line of the optical compensation film with the slow axis of the first optically anisotropic layer as an axis. It represents the retardation value of the first optically anisotropic layer measured from the inclined direction. However, Re (40)> Re (−40). The optical compensation film according to claim 1, wherein the retardation value Re (0) measured from the normal direction of the first optically anisotropic layer satisfies the following mathematical formula (2).
35 <Re (0) <60 ......... Formula (2)   The optical compensation film according to claim 1, wherein the liquid crystalline compound is a discotic liquid crystalline compound.   The optical compensation film according to any one of claims 1 to 3, wherein the second optically anisotropic layer is a cellulose acylate film.   A polarizing plate comprising the optical compensation film according to claim 1 and a polarizing film.   A liquid crystal display device comprising a liquid crystal cell and the polarizing plate according to claim 5.   The liquid crystal display device according to claim 6, wherein a voltage applied to the liquid crystal cell is 5 V or less. The liquid crystal display device according to claim 6, wherein the liquid crystal cell is an OCB method or an ECB method.