JP2013160979A - Ips or ffs liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IPS (in-plane switching) or FFS (fringe field switching) liquid crystal display device that is not only improved in a viewing angle contrast but is excellent in a front contrast.SOLUTION: The IPS or FFS liquid crystal display device includes, in the following order, a first polarizing film, an optical compensation film comprising a first retardation region and a second retardation region in contact with the first retardation region, a first substrate, a liquid crystal layer comprising a nematic liquid crystal material, and a second substrate, in which liquid crystal molecules of the nematic liquid crystal material are aligned parallel to the surfaces of the pair of substrates during black display. The slow axes of the first retardation region and of the second retardation region are parallel to each other; the first retardation region includes a retardation layer containing a vertically aligned discotic liquid crystal compound; and an in-plane retardation Re(550) at a wavelength of 550 nm in the first retardation region is 100 nm or less while an in-plane retardation Re(550) at a wavelength of 550 nm in the second retardation region is 20 nm or more.

Description

  The present invention relates to an IPS or FFS type liquid crystal display device with improved viewing angle characteristics.

  In recent years, IPS (In-Plane Switching) type and FFS (Fringe Field Switching) type liquid crystal display devices have been expanded in applications such as television display devices. Conventionally, it is known that a retardation layer containing a vertically aligned discotic liquid crystal compound contributes to an improvement in viewing angle characteristics of an IPS liquid crystal display device (Patent Documents 1 and 2). By using the retardation layer, the viewing angle contrast can be remarkably improved with a simple configuration.

Japanese Patent No. 4253259 JP 2005-309382 A

However, the IPS liquid crystal display device is required not only to improve the viewing angle contrast but also to have an excellent front contrast.
An object of the present invention is to provide an IPS or FFS type liquid crystal display device that has not only improved viewing angle contrast but also excellent front contrast.

  As a result of intensive studies by the inventor, the above problem is that the in-plane retardation of the first retardation layer containing the vertically aligned discotic liquid crystal compound is set to a predetermined value or less, and the first retardation layer It has been found that the in-plane retardation of the second retardation layer used as a support or the like is a certain value or more, thereby improving the front contrast while maintaining the improvement of the viewing angle contrast. It came to be completed. The effect of the present invention can be obtained not only in the IPS type but also in the FFS type liquid crystal display device similarly classified into the horizontal alignment type.

Means for solving the above-mentioned problems are as follows.
[1] a first polarizing film;
An optical compensation film comprising a first retardation region and a second retardation region in contact with the first retardation region;
A first substrate;
A liquid crystal layer made of a nematic liquid crystal material;
A second substrate;
In this order, and the liquid crystal display device in which the liquid crystal molecules of the nematic liquid crystal material are aligned in parallel to the surfaces of the pair of substrates during black display,
The first retardation region and the slow axis of the second retardation region are parallel to each other;
The first retardation region includes a retardation layer containing a vertically aligned discotic liquid crystal compound, and the in-plane retardation Re (550) of the wavelength of 550 nm of the first retardation region satisfies 100 nm or less, and IPS or FFS type liquid crystal display device satisfying an in-plane retardation Re (550) of 20 nm or more in a two phase difference region with a wavelength of 550 nm:
However, the in-plane retardation Re is defined as Re = (nx−ny) × d using the in-plane refractive indexes nx and ny (nx ≧ ny) and the film thickness d.
[2] In-plane retardations Re1 and Re2 of the first retardation region and the second retardation region satisfy the following relational expression (a), and the thicknesses of the first retardation region and the second retardation region, respectively. The IPS or FFS type liquid crystal display device of [1] in which the direction retardations Rth1 and Rth2 satisfy the following relational expression (b):
(A) −2 × Re1 + 220 ≦ Re2 ≦ −2 × Re1 + 380
(B) −1.5 × Rth1−80 ≦ Rth2 ≦ −1.5 × Rth1 + 30
However, Re1 and Re2 respectively represent Re (550) of the first phase difference region and the second phase difference region, and Rth1 and Rth2 respectively represent thickness directions at a wavelength of 550 nm of the first phase difference region and the second phase difference region. Retardation Rth (550).
[3] The IPS or FFS type liquid crystal display device according to [1] or [2], wherein the absolute value | Rth (550) | of Rth (550) of the entire optical compensation film is 30 nm or less:
However, Rth (550) means the retardation Rth in the thickness direction at a wavelength of 550 nm, and the retardation in the thickness direction has an in-plane refractive index nx and ny (nx ≧ ny), a thickness direction refractive index nz, And Rth = {(nx + ny) / 2−nz} × d using the film thickness d.
[4] Re, Re (450), Re (550), and Re (650) at wavelengths of 450 nm, 550 nm, and 650 nm of the first retardation region have a Re (450) / Re (550) of 1 or more and 1.13. The IPS or FFS type liquid crystal display device according to any one of [1] to [3], wherein Re (650) / Re (550) satisfies 0.94 or more and 1 or less.
[5] The IPS or FFS type liquid crystal display device according to any one of [1] to [4], which is disposed in the order of the first polarizing film, the first retardation region, and the second retardation region.
[6] The IPS or FFS type liquid crystal display device according to any one of [1] to [4], which is disposed in the order of the first polarizing film, the second retardation region, and the first retardation region.
[7] The second retardation region includes a plurality of layers, a layer in contact with the first retardation region among the plurality of layers is an alignment film, and the first retardation region includes a discotic liquid crystal compound and The IPS according to any one of [1] to [6], comprising an composition containing at least an alignment control agent, wherein the alignment control agent has an action of reducing a tilt angle of a director of a discotic liquid crystal compound on the air interface side. Or an FFS type liquid crystal display device.
[8] The IPS or FFS type liquid crystal display device according to any one of [1] to [7], wherein the second retardation region is made of a polymer film.
[9] The IPS or FFS type liquid crystal display device according to [8], wherein the polymer film includes a cellulose acylate film, a cyclic olefin polymer film, or an acrylic polymer film.
[10] The IPS or FFS liquid crystal display device according to [8] or [9], wherein the polymer film is made of a composition containing as a main component a cellulose acylate having an acyl group containing an aromatic group.
[11] The IPS or FFS liquid crystal display device according to [5], wherein the first retardation region has a polymer film together with the retardation layer, and the polymer film is in contact with the first polarizing film.
[12] The IPS according to any one of [1] to [11], further including a second polarizing film outside the second substrate, and a polymer film between the second polarizing film and the second substrate. Or an FFS type liquid crystal display device.
[13] The polymer film has an in-plane retardation Re (550) having an absolute value | Re (550) | of 10 nm or less and an absolute value of retardation Rth (550) in the thickness direction of the same wavelength. The IPS or FFS liquid crystal display device according to [11] or [12], wherein | Rth (550) | is a film having a thickness of 30 nm or less.
[14] The polymer film according to [11] to [13], wherein | Re (400) -Re (700) | is 10 nm or less, and | Rth (400) -Rth (700) | Any IPS or FFS type liquid crystal display device.
[15] The IPS or FFS type liquid crystal display device according to any one of [11] to [14], wherein the polymer film has a thickness of 10 to 90 μm.
[16] The IPS or FFS type liquid crystal display device according to any one of [11] to [15], wherein the polymer film includes a cellulose acylate film, a cyclic olefin polymer film, or an acrylic polymer film.
[17] The acrylic polymer film is an acrylic polymer film containing an acrylic polymer containing at least one unit selected from a lactone ring unit, a maleic anhydride unit, and a glutaric anhydride unit. IPS or FFS type liquid crystal display device.
[18] The IPS or FFS type liquid crystal display device according to any one of [1] to [17], which has a protective film on the other surface of the first polarizing film or the second polarizing film.
[19] The IPS or FFS type liquid crystal display device according to [18], wherein the protective film has a thickness of 10 to 90 μm.
[20] The IPS or FFS type liquid crystal display device according to any one of [1] to [18], wherein the thickness of the first polarizing film or the second polarizing film is 50 μm or less.

  According to the present invention, it is possible to provide an IPS or FFS type liquid crystal display device that has not only improved viewing angle contrast but also excellent front contrast.

It is a cross-sectional schematic diagram of an example of the IPS or FFS type liquid crystal display device of the present invention. It is a cross-sectional schematic diagram of the other example of the IPS or FFS type liquid crystal display device of this invention. It is a cross-sectional schematic diagram of the other example of the IPS or FFS type liquid crystal display device of this invention. It is a cross-sectional schematic diagram of the other example of the IPS or FFS type liquid crystal display device of this invention. It is the schematic which shows the pixel area example which can be used for this invention. It is the figure which showed typically an example of the locus | trajectory of the polarization state which injected into the IPS type | mold liquid crystal display device of Example 1 of this invention on the Poincare sphere. It is the figure which showed typically an example of the locus | trajectory of the polarization state which injected into the IPS type | mold liquid crystal display device of Example 2 of this invention on the Poincare sphere. It is the figure which showed typically an example of the locus | trajectory of the polarization state which injected into the IPS type | mold liquid crystal display device of Example 3 of this invention on the Poincare sphere. It is the figure which showed typically an example of the locus | trajectory of the polarization state which injected into the IPS type | mold liquid crystal display device using a negative C plate and a negative A plate on the Poincare sphere. It is a graph which shows the example of the preferable range of Re1 and Re2 of the 1st and 2nd phase difference area | region in this invention, respectively. It is a graph which shows the example of the preferable range of Rth1 and Rth2 of the 1st and 2nd phase difference field in the present invention, respectively.

  Hereinafter, an embodiment of the liquid crystal display device of the present invention and its constituent members will be described in sequence. 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.

  In this specification, the relationship between the optical axes includes errors allowed in the technical field to which the present invention belongs. Specifically, “parallel” and “orthogonal” mean that the angle is within a strict angle of less than ± 10 °, preferably less than ± 5 °, and less than ± 3 °. More preferred. Further, “vertical alignment” means that it is within a range of less than ± 20 ° from a strict vertical angle, preferably less than ± 15 °, and more preferably less than ± 10 °. . Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.

  In this specification, “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 “cutting out”. It is used in the meaning including both of the polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other, and “polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one surface of the “polarizing film”. It shall be.

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 with KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.) by making light having a wavelength of λ nm incident in the normal direction of the film. In selecting the measurement wavelength λnm, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like. When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method. This measurement method is also partially used for measuring the average tilt angle of the discotic liquid crystal molecules in the optically anisotropic layer (retardation layer) described later on the alignment film side and the average tilt angle on the opposite side. .
Rth (λ) is the film surface when Re (λ) is used and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotation axis) (if there is no slow axis) Measurement is performed at a total of 6 points by injecting light of wavelength λ nm from each inclined direction in steps of 10 degrees from the normal direction to 50 ° on one side with respect to the film normal direction (with any rotation direction as the rotation axis) Then, 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). Rth can also be calculated from the following formula (A) and formula (B) based on the value, the assumed value of the average refractive index, and the input film thickness value.

なお、上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値をあらわす。また、式（Ａ）におけるｎｘは、面内における遅相軸方向の屈折率を表し、ｎｙは、面内においてｎｘに直交する方向の屈折率を表し、ｎｚは、ｎｘ及びｎｙに直交する方向の屈折率を表す。ｄは膜厚を意味する。
Ｒｔｈ＝（（ｎｘ＋ｎｙ）／２−ｎｚ）×ｄ・・・・・・・・・・・式（Ｂ）

Note that Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In the formula (A), nx 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 is the direction orthogonal to nx and ny. Represents the refractive index. d means a film thickness.
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 from −50 ° to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotary axis). Measured at 11 points by making light of wavelength λ nm incident in 10 ° steps up to + 50 °, and based on the measured retardation value, average refractive index assumption value and input film thickness value. KOBRA 21ADH or WR is calculated. In the above measurement, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. If the average refractive index is not known, it can be measured with an Abbe refractometer. The average refractive index values of main optical 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 value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  Unless otherwise specified, the measurement wavelengths of Re and Rth are values at λ = 550 nm in the visible light region.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an embodiment of the IPS or FFS type liquid crystal display device of the present invention.
The liquid crystal display device shown in FIG. 1 includes a pair of first polarizing film 16 and second polarizing film 18, a first phase difference region 20 in contact with the first polarizing film 16, and a second phase difference in contact with the first phase difference region. The optical compensation film F including the region 22 and at least an IPS or FFS type liquid crystal cell LC are provided. A backlight 26 is disposed further outside the second polarizing film 18.

  In the liquid crystal display device of FIG. 1, the liquid crystal cell LC includes a first substrate 12, a liquid crystal layer 10 made of a nematic liquid crystal material, and a second substrate 14. The liquid crystal layer 10 is an IPS or FFS type liquid crystal cell in which liquid crystal molecules of the nematic liquid crystal material are aligned parallel to the surfaces of the pair of substrates 12 and 14 during black display. The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is, in the transmission mode, in the range of 0.2 to 0.4 μm for the IPS type having no twisted structure, and 0 for the FFS type. The optimum value is in the range of 3 to 0.5 μm. In this range, the white display luminance is high and the black display luminance is small, so that a bright and high-contrast display device can be obtained. An alignment film (not shown) is formed on the surfaces of the substrates 12 and 14 that are in contact with the liquid crystal layer 10, and the liquid crystal molecules are aligned substantially parallel to the surface of the substrate and are rubbed on the alignment film. The liquid crystal molecule alignment direction in a voltage non-application state or a low application state is controlled by the processing direction or the like. Further, an electrode (not shown in FIG. 1) capable of applying a voltage to the liquid crystal molecules is formed on the inner surface of the substrate 12 or 14.

  When no voltage is applied, the liquid crystal layer 10 is controlled by the rubbing direction of the alignment film formed on the inner surfaces of the substrates 12 and 14, for example, without twisting the liquid crystal molecules and aligned in a certain horizontal direction. Yes. When a voltage is applied, the liquid crystal molecules are horizontally rotated by a predetermined angle by an electric field formed in the in-plane direction, and are aligned in a predetermined direction. Various shapes and arrangements of electrodes have been proposed, and any of them can be used. FIG. 5 schematically shows an example of the alignment of liquid crystal molecules in one pixel region of the liquid crystal layer 10. FIG. 5 shows the alignment of the liquid crystal molecules in a very small area corresponding to one pixel of the liquid crystal layer 10 in the rubbing direction 4 of the alignment film formed on the inner surfaces of the substrates 12 and 14 and the substrates 12 and 14. It is an example of the schematic diagram shown with the electrodes 2 and 3 which can apply a voltage to the liquid crystal molecule formed in the inner surface. When active driving is performed using a nematic liquid crystal having positive dielectric anisotropy as a field effect liquid crystal, the liquid crystal molecule alignment directions in a no voltage application state or a low application state are 5a and 5b. A display is obtained. When applied between the electrodes 2 and 3, the liquid crystal molecules change their alignment direction in the directions of 6 a and 6 b in accordance with the voltage. Normally, white display is performed in this state.

  In FIG. 1 again, the absorption axis 16a of the first polarizing film 16 and the absorption axis 18a of the second polarizing film 18 are arranged orthogonally. When no voltage is applied, the liquid crystal molecules of the liquid crystal layer 10 are horizontally aligned so that the slow axis 10 a of the liquid crystal layer 10 is parallel to the absorption axis 18 a of the second polarizing film 18. Accordingly, the light incident from the backlight 26 passes through the liquid crystal layer 10 while maintaining the polarization state substantially, is blocked by the absorption axis 16a of the first polarizing film 16, and becomes black. However, light incident from an oblique direction among the light incident from the backlight 26 causes light leakage because the absorption axes 16a and 18a of the polarizing films 16 and 18 are shifted from the orthogonal relationship, that is, The viewing angle contrast is reduced. The optical compensation film F has an effect of reducing the light leakage and improving the viewing angle contrast.

  The optical compensation film F includes, for example, a second retardation region 22 including a polymer film that can be a support and a first retardation region 20 including a retardation layer containing a vertically aligned discotic liquid crystal compound. When a retardation layer containing a vertically aligned discotic liquid crystal compound is used for viewing angle compensation of a horizontally aligned liquid crystal display device such as an IPS mode, light leakage in an oblique direction during black display is reduced, and the viewing angle contrast becomes remarkable. Improved.

Here, considering the conventional optical compensation effect of a horizontal alignment mode liquid crystal display device using a retardation layer containing a vertically aligned discotic liquid crystal compound, one example is the polarization state on the Poincare sphere shown in FIG. This can be explained by the trajectory. Conventionally, as shown in FIG. 9, a retardation layer containing a vertically aligned discotic liquid crystal compound is used as a so-called negative A plate, and the retardation layer exhibits so-called negative C plate-like optical characteristics. By combining with a retardation film or the like, optical compensation as shown in FIG. 9 was achieved.
9 is a horizontal alignment type liquid crystal display device having the same configuration as that in FIG. 1, and a negative C plate is used instead of the second retardation region 22 and a negative C plate is used instead of the first retardation region 20. In a liquid crystal display device having a configuration in which an A plate is disposed and a film having both Re and Rth of approximately 0 nm, such as a Z-TAC film (manufactured by Fujifilm), as a protective film 24, is obliquely displayed during black display. It is the figure which showed typically the change of the polarization state of the light which injected into (polar angle 60 degrees, azimuth | direction angle 135 degrees) as a locus | trajectory on a Poincare sphere.

  However, as a result of investigation by the present inventor, when a horizontally aligned liquid crystal display device is optically compensated by using a retardation layer containing a vertically aligned discotic liquid crystal compound, the front angle is improved while maintaining the improvement of the viewing angle contrast. It was found that it was difficult to improve the contrast at the same time. This is caused by scattering in the retardation layer containing a vertically aligned discotic liquid crystal compound due to alignment fluctuations of liquid crystal molecules, which contributes to a decrease in front contrast. By reducing the thickness of the retardation layer, it is possible to reduce the influence of scattering due to fluctuations in the orientation of liquid crystal molecules, but on the other hand, the Re layer of the retardation layer becomes insufficient due to the thinner layer, and the locus shown in FIG. Therefore, the polarization state of the passing light cannot be converted, and the viewing angle contrast is lowered. In the present invention, sufficient optical characteristics for optical compensation can be obtained by causing the second retardation region to bear part of the retardation necessary for optical compensation in the first retardation region containing the discotic liquid crystal compound. While improving the front contrast.

  The optical compensation in the present invention is different from the conventional optical compensation action achieved by the combination of the negative A plate and the negative C plate as shown in FIG. As will be described later in detail), the polarization state of the light passing through the laminated body of the first and second retardation regions is converted by the same trajectory as passing through the so-called λ / 2 plate. There is a feature that is. Therefore, this is different from the conventional optical compensation principle in a horizontal alignment type liquid crystal display device using a retardation layer containing a vertically aligned discotic liquid crystal compound.

In the optical compensation, the first retardation region 20 satisfies Re (550) of 100 nm or less.
As long as this optical characteristic is satisfied, there is no particular limitation on Rth. However, the absolute value of Rth (550) as the entire optical compensation film F including the first retardation region 20 and the second retardation region 22 is 30 nm. The following is preferable in terms of improving the viewing angle contrast.
When the black display is viewed using the configuration of FIG. 1 as an example, light incident in an oblique direction from the backlight 26 passes through the second polarizing film 18, the liquid crystal layer 10, the optical compensation film F, and the first polarizing film 16. When the transition of the polarization state caused by this is shown on the Poincare sphere, the polarized light (incident polarized light) that has passed through the second polarizing film follows the orbit as shown in FIGS. 6 to 8 by the optical compensation film F. As shown, it changes to polarized light (emitted polarized light) before passing through the first polarizing film. Since the emitted polarized light at this time is in a crossed Nicols relationship with the first polarizing film, the luminance of black display can be suppressed. As a result of intensive studies by the present inventors, it has been found that when the absolute value of Rth (550) of the optical compensation film F is 30 nm or less, the relationship between the output polarized light and the crossed Nicols of the first polarizing film is good.

  In the second phase difference region 22, Re (550) satisfies 20 nm or more. As long as the second retardation region 22 satisfies this optical characteristic, the material thereof is not particularly limited, and may be a single layer structure or a laminated structure including two or more layers. It is preferable to include a self-supporting polymer film because it can be used as a support for the first retardation region 20 formed by coating or the like. An example is an example in which the second retardation region 22 is a laminate including a polymer film and an alignment film, and the alignment film is in contact with the first retardation region 20. The surface of the alignment film may be subjected to rubbing treatment, and the rubbing treatment direction is parallel to the slow axis direction of the polymer film (generally in many cases coincides with the longitudinal direction of the polymer film). It is preferable because it is excellent in production suitability. Examples of the polymer film and the alignment film that can be used in the second retardation region will be described later.

A retardation layer containing a discotic liquid crystal fixed in a vertically aligned state usually has optical characteristics as a negative A plate (Rth = −1 / 2 × Re is established in an ideal negative A plate). Show. While utilizing the first phase difference region acting like a negative A plate, the optical compensation using the conventional negative A plate (optical compensation by conversion of the polarization state as shown in FIG. 9) is not used. In order to achieve optical compensation by converting the polarization state as shown in FIG. 8, the in-plane retardations Re1 and Re2 of the first and second retardation regions are in the above range, and the following relational expression (a It is preferable that retardation Rth1 and Rth2 in the thickness direction of each of the first and second retardation regions satisfy the following relational expression (b).
(A) −2 × Re1 + 220 ≦ Re2 ≦ −2 × Re1 + 380
(B) −1.5 × Rth1−80 ≦ Rth2 ≦ −1.5 × Rth1 + 30
In the table below, when Re1 in the first retardation region is 0 to 100 nm and Re2 in the second retardation region is 20 nm or more, the above relational expression (a) is satisfied and | Rth | A combination example in which (that is, | Rth1 + Rth2 |) is 30 nm or less and satisfies the relational expression (b) is shown. However, it is not limited to the combination examples shown in the following table. In the table below, the numerical values in parentheses described in the Re2 and Rth2 columns of the second retardation region mean optimum values. In addition, for the first phase difference region, an example satisfying Rth = −1 / 2 × Re has been shown. However, as described in each column, Re1 has the same effect even if there is an error of about ± 10 nm. The same effect can be obtained even if there is an error of about ± 5 nm for Rth1.

  A graph showing a preferable range of Re2 and Rth2 in the second retardation region when Re1 and Rth1 in the first retardation region are specified to the values described in the table, for each combination example described in the table. Are shown in FIGS. 10 and 11, respectively. In FIG. 10 and FIG. 11, each point represents a combination of the optimum values of Re1 and Re2, and a combination of the optimum values of Rth1 and Rth2. In FIGS. 10 and 11, the range indicated by the perpendicular line drawn from each point to two straight lines is the second phase difference region when the first phase difference regions Re1 and Rth1 are the values described in the above table, respectively. The preferred ranges of Re2 and Rth2 are shown respectively. In particular, the combination of Examples 2 to 4 is preferable.

  Further, the Re wavelength dispersion of the first retardation region 20 is such that Re (450) / Re (550) is 1 or more and 1.13 or less and Re (650) / Re (550) is 0.94 or more and 1 When the following is satisfied, the color shift occurring in the oblique direction can be further reduced, which is preferable. One cause of the color shift in the oblique direction is that the retardation of the retardation layer used for optical compensation is not suitable for wavelength dispersion. In general, the Re wavelength dispersion of a retardation layer formed using a discotic liquid crystal compound is determined by the properties of the discotic liquid crystal compound used. In order to reduce the color shift, Re of the retardation layer is ideally reverse wavelength dispersive in the visible light region, but on the other hand, it is generally formed using a discotic liquid crystal compound. The Re of the retardation layer has forward wavelength dispersion. As a result of intensive studies by the present inventor, when the wavelength dispersion of Re in the first phase difference region 20 satisfies the above relational expression, the color shift can be reduced to such an extent that even if it is observed with human eyes, there is no sense of incongruity. all right. Examples of discotic liquid crystal compounds that satisfy this characteristic will be described later.

  In the liquid crystal display device of FIG. 1, a protective film 24 for the second polarizing film 18 is disposed between the second polarizing film 18 and the liquid crystal cell LC. From the viewpoint of improving the viewing angle contrast, the protective film 24 preferably has a low phase difference. Specifically, the absolute value | Re (550) | of Re (550) is 10 nm or less (more preferably 5 nm or less). And the absolute value | Rth (550) | of Rth (550) is preferably 30 nm or less (more preferably 15 nm or less). In addition, the protective film 24 preferably has low wavelength dispersion from the viewpoint of reducing the color shift that occurs in an oblique direction. Specifically, | Re (400) −Re (700) | is 10 nm or less ( More preferably, it is 5 nm or less), and | Rth (400) −Rth (700) | is 35 nm or less (more preferably 15 nm or less). The protective film 24 preferably has a certain thickness from the viewpoint of durability, and specifically, the thickness is preferably 10 to 90 μm (more preferably 40 to 80 μm). Examples of polymer films that can be used as the protective film 24 will be described later.

  The protective film 24 is disposed for improving the durability of the second polarizing film 18 and the adhesiveness between the second polarizing film 18 and the substrate 14. If the adhesiveness with the substrate 14 is sufficient, it is not necessary.

  It is preferable that a protective film is disposed on the outer surfaces of the first polarizing film 16 and the second polarizing film 18, and the first polarizing film 16 has an optical compensation film F on one surface thereof, and the other surface. The polarizing plate POL1 having a protective film and the second polarizing film 18 may be incorporated in a liquid crystal display device as a polarizing film POL2 having a protective film 24 on one surface and a protective film on the other surface. Good.

  The surface of the optical compensation film F that adheres to the first polarizing film 16 is a first retardation region 20 including a retardation layer containing a vertically aligned discotic liquid crystal, and the first retardation region 20 is a disco layer. When it consists only of the retardation layer formed by hardening | curing the curable composition containing a tick liquid crystal compound, the adhesiveness with the 1st polarizing film 16 may be weak. A polymer film may be laminated on the surface of the retardation layer to improve adhesiveness with the first polarizing film 16. From the viewpoint of improving the viewing angle contrast, the polymer film is preferably a film having low Re and low Rth and small wavelength dispersion of Re and Rth, that is, exhibiting the same optical characteristics as the protective film 24. preferable.

  Further, the first phase difference region 20 and the second phase difference region 22 may be arranged interchangeably, that is, the configuration shown in FIG. In any configuration, the same effect of improving both the viewing angle contrast and the front contrast can be obtained. In the configuration of FIG. 2, the adhesion between the optical compensation film F and the first polarizing film 16 can be improved, which is preferable from the viewpoint of durability, but on the other hand, the first retardation region 20 and the second retardation region 22 are delayed. Suitable for roll-to-roll systems where the phase axis needs to be rotated 90 degrees, and a protective film with a pressure-sensitive adhesive laid on one side and a different type of roll-shaped optical compensation film F on the other side are adhered while being conveyed to each other 1 is preferable because the productivity is deteriorated.

The configuration of the backlight 26 is not particularly limited. Any of a light guide plate method and a direct type method may be used. The light guide plate type backlight unit includes a light source and a light guide plate, and the direct type backlight unit includes a light source and a diffusion plate. The light source used is not particularly limited, and any of light bulbs, light emitting diodes (LEDs), electroluminescence panels (ELP), one or more cold cathode fluorescent lamps (CCFL), hot cathode fluorescent lamps (HCFL), etc. should be used. Can do.
The backlight 26 can be made of a member such as a reflector or a brightness enhancement film in order to increase the light use efficiency. Furthermore, when forming the liquid crystal display device, in addition to the above-described members, for example, components such as a diffusion plate, a protective plate, a prism array, a lens array sheet, and a light diffusion plate can be appropriately arranged in one layer or two or more layers.

  1 and 2 show the configuration in which the backlight 26 is disposed outside the second polarizing film 18, the backlight 26 may be disposed outside the first polarizing film 16, that is, FIG. And the structure of FIG. 4 may be sufficient. The same effects as in FIGS. 1 and 2 can be obtained.

  The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective when applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as TFT or MIM. Of course, a mode applied to a passive matrix liquid crystal display device called time-division driving is also effective.

  Hereinafter, preferred optical characteristics of various members usable in the liquid crystal display device of the present invention, materials used for the members, manufacturing methods thereof, and the like will be described in detail.

1. Optical Compensation Film The liquid crystal display device of the present invention has an optical compensation comprising a first retardation region including a retardation layer containing a vertically aligned discotic liquid crystal compound, and a second retardation region in contact with the first retardation region. One feature is that the film has a film, and the Re of the first retardation region and the second retardation region are both within a predetermined range. In the optical compensation film, the slow axis of the first retardation region and the slow axis of the second retardation region are parallel. Each of the first and second retardation regions may have a single layer structure or a laminated structure including two or more layers. By using the compensation film, the present invention not only improves the viewing angle contrast but also improves the front contrast.

Re (550) of the first retardation region is 100 nm or less, and from the viewpoint of improving front contrast, Re is preferably lower. However, from the viewpoint of manufacturability, it is preferably 0 nm or more, more preferably 20 to 100 nm, still more preferably 30 to 90 nm, and even more preferably 40 to 80 nm.
Re (550) of the second retardation region is 20 nm or more, and from the viewpoint of improving front contrast, it is preferably 60 to 340 nm, and more preferably 150 to 300 nm. Although there is no restriction | limiting in particular about Rth (550) of a 2nd phase difference area | region, From a viewpoint of improving a viewing angle contrast, it is preferable that it is -65-90 nm, and it is more preferable that it is -50-75 nm. Further, Re and Rth in the second retardation region preferably satisfy the above relational expressions (a) and (b) in relation to Re and Rth in the first retardation region.

  Further, the wavelength dispersion in the visible light region of the retardation of the first retardation region affects the color shift that occurs in the oblique direction. From the viewpoint of reducing the color shift, it is ideal that the wavelength dispersion of Re in the first retardation region is reverse wavelength dispersion, but in general, it is formed by fixing the orientation of the discotic liquid crystal compound. The Re wavelength dispersion of the retardation layer tends to be forward wavelength dispersion. As a result of intensive studies by the present inventors, even if Re in the first retardation region is not reverse wavelength dispersive, Re (450) / Re (550) is 1 or more and 1.13 or less (more preferably 1-1. 10), if Re (650) / Re (550) is 0.94 or more and 1 or less (more preferably 0.96 to 1.0), the occurrence of oblique color shift can be reduced, and this is a practical problem. I knew it was n’t there. Examples of the discotic liquid crystal compound capable of achieving the wavelength dispersion include a discotic liquid crystal compound represented by the formula (I) described later.

  On the other hand, although there is no particular limitation on Rth of the first retardation region and the second retardation region, the absolute value of Rth (550) is 30 nm or less from the viewpoint of improving the viewing angle contrast as the entire optical compensation film. Is preferred. In particular, if | Rth (550) | as the entire optical compensation film exceeds 30 nm, the viewing angle contrast may deteriorate.

  An example of the optical compensation film is formed from a composition containing a discotic liquid crystal compound disposed in contact with the second retardation region composed of a polymer film and an alignment film formed thereon, and the alignment film. An optical compensation film comprising a first retardation region including a retardation layer. When the optical compensation film having the structure is continuously produced in a long shape, from the viewpoint of production suitability, the longitudinal direction of the polymer film serving as a support (usually coincides with the slow axis of the polymer film) and orientation In general, the alignment control direction of the film (for example, the rubbing treatment direction in the case of a rubbing alignment film) is matched. Generally, disk-like liquid crystal molecules are vertically aligned (hereinafter sometimes referred to as “parallel vertical alignment”) by inserting the disk surface along grooves on the alignment film surface formed by rubbing. The slow axis of the retardation layer formed by fixing the orientation state is parallel to the slow axis of the polymer film.

Hereinafter, materials and methods used for manufacturing the optical compensation film having the above-described configuration will be described in detail.
(1) Second retardation region An example of the second retardation region used in the optical compensation film having the above-described configuration is a laminated film having at least a polymer film serving as a support and an alignment film thereon.
Polymer film:
As long as the optical characteristics are exhibited, there is no particular limitation on the material of the polymer film used in the second retardation region. Examples include cellulose acylate (for example, cellulose triacetate (refractive index 1.48), cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate), polyethylene terephthalate, polyethersulfone, polyacrylic resin, polyurethane. Resin, polyester, polycarbonate, polysulfone, polyether, polymethylpentene, polyetherketone, (meth) acrylonitrile, polyolefin, polymer having an alicyclic structure (norbornene resin (Arton: trade name, manufactured by JSR, Crystalline polyolefin (ZEONEX: trade name, manufactured by Nippon Zeon Co., Ltd.), polypropylene, etc. Among these, triacetyl cellulose, polyethylene terephthalate, polycyclic alicyclic structure. Mer are preferred, triacetyl cellulose is preferred.

The cellulose acylate film is preferably a cellulose acylate having an acyl group (substituent A) containing an aromatic group. The substitution position of the substituent A in the cellulose acylate may be any of the 2-position, the 3-position, and the 6-position, and the substitution degree at each substitution position is not particularly limited. The degree of substitution of the substituent A is preferably 0.5 to 1.5, and more preferably 0.7 to 1.3. If the substitution degree of the substituent A is less than 0.5, the Re expression will be reduced, and it will be difficult to achieve high Re. Moreover, when the substitution degree of the substituent A is larger than 1.5, it is difficult to produce the raw material because synthesis takes time.
In addition, there may be a plurality of types of acyl groups including an aromatic group, and when there are a plurality of types, the degree of substitution is the total. From the viewpoint of synthesis, it is preferable that the acyl group containing an aromatic group is one kind.

  Further, the total substitution degree DS with the acyl group in the cellulose acylate (not only the substitution degree with the substituent A but also the substitution degree with the substitution group B described later) is 2.2 to 3 0.0 is preferable, 2.5 to 2.95 is more preferable, and 2.5 to 2.9 is more preferable. A total substitution degree DS in the above range is preferable from the viewpoint of reducing the humidity dependence of Rth.

In the present invention, the substitution degree and substitution degree distribution of the substituents are determined by ¹ H-NMR or ¹³ using the methods described in Cellulose Communication 6, 73-79 (1999) and Chirality 12 (9), 670-674. It can be determined by C-NMR.

(Acyl group containing aromatic group (Substituent A))
The acyl group (substituent A) containing an aromatic group may be directly bonded to the ester bond or may be bonded via a linking group, but is preferably directly bonded. Here, the linking group represents an alkylene group, an alkenylene group, or an alkynylene group, and the linking group may have a substituent. As the linking group, preferably an alkylene group having 1 to 10 atoms, an alkenylene group, and an alkynylene group, more preferably an alkylene group having 1 to 6 atoms and an alkenylene group, and most preferably an alkylene and alkenylene group having 1 to 4 atoms. is there.

The cellulose acylate having an acyl group containing an aromatic group (substituent A) is an acyl group other than an acyl group containing an aromatic group (substituent A), specifically an aliphatic acyl group (substituent B). May further be included.
(Aliphatic acyl group (substituent B)
The aliphatic acyl group (substituent B) in the present invention may be a linear, branched or cyclic aliphatic acyl group, or may be an aliphatic acyl group containing an unsaturated bond. Good. Preferably it is a C2-C20, More preferably, it is C2-C10, More preferably, it is a C2-C4 aliphatic acyl group. Preferable examples of the substituent B are an acetyl group, a propionyl group, and a butyryl group, and among them, an acetyl group is preferable. By using the substituent B as an acetyl group, a film having an appropriate glass transition point (Tg), elastic modulus and the like can be obtained. By having an aliphatic acyl group having a small number of carbon atoms, such as an acetyl group, an appropriate strength as a film can be obtained without lowering Tg, elastic modulus and the like. The substitution degree DSB of the substituent B is preferably 1.70 to 2.89, more preferably 1.70 to 2.80, and still more preferably 1.75 to 2.80. When the DSB is in the above range, the solubility can be kept high, and the synthesis becomes easy, which is preferable.

  The cellulose acylate film used as all or part of the second retardation region is preferably formed by a solvent cast method. About the manufacture example of the cellulose acylate film using a solvent cast method, U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, 2,492,978, 2,607,704, 2,739,069 and 2,739,070, British Patent Nos. 640731 and 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, and JP-A-62-115035 can be referred to. The cellulose acylate film may be subjected to a stretching treatment. With respect to the stretching method and conditions, for example, refer to JP-A-62-115035, JP-A-4-152125, 4-284221, 4-298310, and 11-48271. can do.

Examples of methods for stretching in the width direction (TD stretching) include, for example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284221, JP-A-4-298310, and JP-A-11-48271. It is described in. In the case of stretching in the width direction, the film can also be stretched by conveying the film while holding it with a tenter and gradually widening the tenter. After the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine). In the case of longitudinal stretching (MD stretching), for example, two pairs of nip rolls are installed, and the peripheral speed of the nip roll on the outlet side is made faster than the peripheral speed of the nip roll on the inlet side while heating between them. Under the present circumstances, the expression of the retardation of the thickness direction can be changed by changing the space | interval (L) between nip rolls, and the film width (W) before extending | stretching. When L / W exceeds 2 and is 50 or less (long span stretching), Rth can be decreased, and when L / W is 0.01 to 0.3 (short span stretching), Rth can be increased. In the present invention, any of a long span stretching, a short span stretching, and a region between them (intermediate stretching = L / W is more than 0.3 and 2 or less) may be used. Short span stretching is preferred. Further, when aiming at high Rth, it is more preferable to use short span stretching, and when aiming at low Rth, it is distinguished from long span stretching.
The preferred stretching temperature of these longitudinal stretching is (Tg-10 ° C) to (Tg + 50) ° C, more preferably (Tg-5 ° C) to (Tg + 40) ° C, with respect to the glass transition temperature Tg of the film. More preferably, it is (Tg + 5) to (Tg + 30) ° C. The film is stretched by adjusting the speed of the film conveying roller so that the film winding speed is higher than the film peeling speed.

  In addition, the 2nd phase difference area | region may consist of the said polymer film independent. Moreover, the cured layer which consists of a curable composition may be sufficient, and the layer formed by apply | coating and drying the coating liquid containing a polymeric material may be sufficient. Examples of the curable composition include a curable composition containing a liquid crystal compound.

  It is preferable that the second retardation region is continuously manufactured in a long state. When the second retardation region is formed from a stretched polymer film, the angle of the slow axis can be adjusted depending on the stretching direction. When the second retardation region is formed of a liquid crystalline compound, the angle of the slow axis of the second retardation region can be adjusted by the rubbing angle. When the slow axis of the second retardation region is parallel or orthogonal to the longitudinal direction of the long film, it becomes possible to bond the long polarizing film and the roll-to-roll. It is possible to manufacture a polarizing plate with high axial angle accuracy and high productivity.

  The surface of the polymer film is subjected to surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment, alkali saponification) treatment for the purpose of improving adhesion to the alignment film. May be. An adhesive layer (undercoat layer) may be provided. In this embodiment, the back surface of the polymer film (the surface on which the alignment film and the second retardation region are not formed) is adhered to the polarizing film, so that the back surface is also subjected to surface treatment such as alkali saponification treatment. Is preferred.

Alignment film:
An example of the alignment film that can be used in this embodiment is not particularly limited, but among them, a rubbing alignment film formed by rubbing the surface of a film made of a composition containing a polymer as a main component is preferable. Examples of polymers that can be used for forming the alignment film include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohols, and modified compounds described in paragraph No. [0022] of JP-A-8-338913. Polyvinyl alcohol, poly (N-methylol acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate and the like are included. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. . The saponification degree of polyvinyl alcohol is preferably 70 to 100%, and more preferably 80 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.

In order to form the alignment film, a crosslinking reaction may be allowed to proceed. In order to advance the crosslinking reaction, a polymer having a crosslinkable functional group in the side chain may be used as the main component polymer, or a crosslinking agent may be used or used in combination.
The alignment film can be formed by applying a coating liquid containing the main component polymer on the surface of the polymer film, drying, and allowing a crosslinking reaction to proceed as desired. Examples of available coating methods include spin coating, dip coating, curtain coating, extrusion coating, rod coating or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm.

  After film formation, the film surface is rubbed. From the viewpoint of production suitability, the rubbing treatment is preferably performed along the transport direction of the polymer film, that is, along the longitudinal direction of the continuously produced long film. The rubbing treatment can be carried out by rubbing the surface of the membrane in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like.

  In addition, a photo-alignment film can also be used as the alignment film.

  In this way, the polymer film having predetermined optical characteristics and an alignment film are provided, and the slow axis direction of the polymer film (generally coincides with the longitudinal direction of the polymer film in many cases) and the alignment A second retardation region made of a laminated film in which the orientation control direction of the film (rubbing treatment direction in the case of a rubbing alignment film) coincides can be produced.

(2) First retardation region One example of the first retardation region has a retardation layer formed by curing a curable composition containing a discotic liquid crystal compound, or the retardation layer and a polymer film thereon. It is a laminate. The said polymer film is used for the improvement of adhesiveness with a 1st polarizing film, and it is preferable to arrange | position as an outermost layer adhere | attached with a 1st polarizing film. The polymer film included in the first retardation region and disposed as the outermost layer bonded to the first polarizing film may function as a protective film for the first polarizing film. Although the preferable example of the protective film of a 1st and 2nd polarizing film is mentioned later, the example of the protective film mentioned later is contained in the example of the polymer film contained in a 1st phase difference area | region, and the preferable range of an optical characteristic. The preferable range of the film thickness is also the same.
Examples of discotic liquid crystal compounds that can be used to form the first retardation region include various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981)). Edited by Chemical Society of Japan, Quarterly Chemical Review, No. 22, Chemistry of Liquid Crystal, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., vol. 116, page 2655 (1994)).

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound is conceivable. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 1 to 12. Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the above formula are (D1) to (D15) described in JP-A No. 2001-4837, respectively. ), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used. In addition, the discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystalline compound is preferably 30 to 300 ° C, and more preferably 30 to 170 ° C.

  Among them, the compound represented by the following general formula (I) is suitable for forming a retardation layer in which Re is the above-described preferable wavelength dispersibility.

In the formula, Y ¹¹ , Y ¹² and Y ¹³ each independently represent a methine or nitrogen atom which may be substituted; L ¹ , L ² and L ³ each independently represent a single bond or a divalent linking group. H ¹ , H ² and H ³ each independently represent a group of the general formula (IA) or (IB); R ¹ , R ² and R ³ each independently represent the following general formula Represents (IR);

In the general formula (IA), YA ¹ and YA ² each independently represents a methine or nitrogen atom; XA represents an oxygen atom, a sulfur atom, methylene or imino; * represents the above general formula (I) Represents a position bonded to the L ^{1 to} L ³ side; ** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I);

In the general formula (IB), YB ¹ and YB ² each independently represent a methine or nitrogen atom; XB represents an oxygen atom, a sulfur atom, methylene or imino; * represents the above general formula (I) Represents a position bonded to the L ^{1 to} L ³ side; ** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I);

General formula (IR)
*-(-L ²¹ -Q ² ) _n1 -L ²² -L ²³ -Q ¹
In the general formula (IR), * represents a position bonded to the H ^{1 to} H ³ side in the general formula (I); L ²¹ represents a single bond or a divalent linking group; Q ² is at least 1 It represents the type of divalent group having a cyclic structure (cyclic group); n1 represents an integer of 0 to 4; L ²² is, ** - O -, ** - O-CO -, ** - CO -O -, ** - O-CO -O -, ** - S -, ** - NH -, ** - SO 2 -, ** - CH 2 -, ** - CH = CH- or ** —C≡C—; L ²³ represents —O—, —S—, —C (═O) —, —SO ₂ —, —NH—, —CH ₂ —, —CH═CH— and —C. Represents a divalent linking group selected from the group consisting of ≡C— and combinations thereof; Q ¹ represents a polymerizable group or a hydrogen atom;

  Paragraphs [0013] of JP 2010-244038 A describe preferred ranges of the respective symbols of the trisubstituted benzene-based discotic liquid crystal compound represented by the formula (I) and specific examples of the compound of the formula (I). To [0077] description can be referred to. However, the discotic liquid crystal compound that can be used in the present invention is not limited to the trisubstituted benzene-based discotic liquid crystal compound of the formula (I).

  Examples of the triphenylene compound include compounds described in paragraphs [0062] to [0067] of JP-A-2007-108732, but the present invention is not limited thereto.

[Vertical alignment accelerator]
In forming the retardation layer, in order to uniformly align the molecules of the liquid crystalline compound vertically, an alignment control agent capable of vertically controlling the liquid crystalline compound on the alignment film interface side and the air interface side is used. Is preferred. The action of vertically aligning the discotic liquid crystal compound corresponds to the action of reducing the tilt angle of the director, that is, the angle formed between the director and the liquid crystal air side surface. In particular, it is preferable to use an air interface vertical alignment accelerator having an action of reducing the tilt angle of the director of the discotic liquid crystal compound on the air interface side.
Examples of the vertical alignment accelerator include a compound that acts to align the liquid crystalline compound vertically by an excluded volume effect, an electrostatic effect or a surface energy effect on the alignment film, and an air interface at the time of alignment of the liquid crystalline compound. A compound that is unevenly distributed and acts to vertically align the liquid crystalline compound by its excluded volume effect, electrostatic effect, or surface energy effect is included.

As the compound (alignment film interface side vertical alignment agent) that promotes the vertical alignment of the molecules of the liquid crystal compound on the alignment film interface side, a pyridinium derivative is preferably used. As a compound (air interface side vertical alignment agent) that promotes the vertical alignment of the molecules of the liquid crystal compound on the air interface side, a fluoro aliphatic group that promotes the uneven distribution of the compound on the air interface side, One or more hydrophilic groups selected from the group consisting of a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and salts thereof. A compound is preferably used. Further, by blending these compounds, for example, when a liquid crystalline composition is prepared as a coating solution, the coating property of the coating solution is improved, and the occurrence of unevenness and repellency is suppressed. The vertical alignment agent will be described in detail below.

[Alignment film interface side vertical alignment agent]
As the alignment film interface side vertical alignment agent usable in the present invention, a pyridinium derivative (pyridinium salt) represented by the following formula (II) is preferably used. By adding at least one of the pyridinium derivatives to the liquid crystalline composition, the molecules of the discotic liquid crystal compound can be aligned substantially vertically in the vicinity of the alignment film.

In the formula, L ²³ and L ²⁴ each represent a divalent linking group.
L ²³ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═CH—, —N═. N-, -O-AL-O-, -O-AL-O-CO-, -O-AL-CO-O-, -CO-O-AL-O-, -CO-O-AL-O- CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO-AL-CO-O-. And AL is an alkylene group having 1 to 10 carbon atoms. L ²³ represents a single bond, —O—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, — CO-O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO- AL-CO-O- is preferable, a single bond or -O- is more preferable, and -O- is most preferable.

L ²⁴ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═CH— or —N═. N- is preferred, and -O-CO- or -CO-O- is more preferred. When m is 2 or more, it is more preferable that the plurality of L ²⁴ are alternately —O—CO— and —CO—O—.

R ²² is a hydrogen atom, an unsubstituted amino group, or a substituted amino group having 1 to 25 carbon atoms.
When R ²² is a dialkyl-substituted amino group, two alkyl groups may be bonded to each other to form a nitrogen-containing heterocycle. The nitrogen-containing heterocycle formed at this time is preferably a 5-membered ring or a 6-membered ring. R ²³ is more preferably a hydrogen atom, an unsubstituted amino group, or a dialkyl-substituted amino group having 2 to 12 carbon atoms, and a hydrogen atom, an unsubstituted amino group, or a dialkyl-substituted group having 2 to 8 carbon atoms. Even more preferred is an amino group. When R ²³ is an unsubstituted amino group or a substituted amino group, the 4-position of the pyridinium ring is preferably substituted.

X is an anion.
X is preferably a monovalent anion. Examples of anions include anions of halogens (eg, fluorine ions, chlorine ions, bromine ions, iodine ions, etc.), sulfonate ions (eg, methanesulfonate ions, trifluoromethanesulfonate ions, methyl sulfate) Ion, p-toluenesulfonic acid ion, p-chlorobenzenesulfonic acid ion, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion, etc.), sulfate ion, carbonate ion , Nitrate ion, thiocyanate ion, perchlorate ion, tetrafluoroborate ion, picrate ion, acetate ion, formate ion, trifluoroacetate ion, phosphate ion (for example, hexafluorophosphate ion), hydroxide ion, etc. Is mentioned. X is preferably a halogen anion, a sulfonate ion, or a hydroxide ion.

Y ²² and Y ²³ are each a divalent linking group having a 5- or 6-membered ring as a partial structure.
The 5- or 6-membered ring may have a substituent. Preferably, at least one of Y ²² and Y ²³ is a divalent linking group having a 5- or 6-membered ring having a substituent as a partial structure. Y ²² and Y ²³ are preferably each independently a divalent linking group having a 6-membered ring which may have a substituent as a partial structure. The 6-membered ring includes an aliphatic ring, an aromatic ring (benzene ring) and a heterocyclic ring. Examples of the 6-membered aliphatic ring include a cyclohexane ring, a cyclohexene ring, and a cyclohexadiene ring. Examples of 6-membered heterocycles include pyran ring, dioxane ring, dithiane ring, thiine ring, pyridine ring, piperidine ring, oxazine ring, morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. Including. Another 6-membered ring or 5-membered ring may be condensed to the 6-membered ring.
Examples of the substituent include a halogen atom, cyano, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. The alkyl group and the alkoxy group may be substituted with an acyl group having 2 to 12 carbon atoms or an acyloxy group having 2 to 12 carbon atoms. The substituent is preferably an alkyl group having 1 to 12 (more preferably 1 to 6, more preferably 1 to 3) carbon atoms. The number of substituents may be 2 or more. For example, when Y ²² and Y ²³ are a phenylene group, the number of carbon atoms of 1 to 4 is 1 to 12 (more preferably 1 to 6, more preferably 1 to The alkyl group of 3) may be substituted.

Here, m is 1 or 2, and is preferably 2. When m is 2, the plurality of Y ²³ and L ²⁴ may be the same as or different from each other.

Z ²¹ is halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 25 carbon atoms, phenyl substituted with an alkoxy group having 1 to 25 carbon atoms, carbon atoms An alkyl group having 1 to 25 carbon atoms, an alkynyl group having 2 to 25 carbon atoms, an alkoxy group having 1 to 25 carbon atoms, an alkoxycarbonyl group having 1 to 25 carbon atoms, and 7 to 26 carbon atoms And a monovalent group selected from the group consisting of an arylcarbonyloxy group having 7 to 26 carbon atoms.
When m is 2, Z ²¹ is preferably cyano, an alkyl group having 1 to 25 carbon atoms, or an alkoxy group having 1 to 25 carbon atoms, and is an alkoxy group having 4 to 20 carbon atoms. Is more preferable.
When m is 1, Z ²¹ is an alkyl group having 7 to 25 carbon atoms, an alkoxy group having 7 to 25 carbon atoms, an acyl-substituted alkyl group having 7 to 25 carbon atoms, or 7 carbon atoms. An acyl-substituted alkoxy group having ˜25, an acyloxy-substituted alkyl group having 7 to 12 carbon atoms, or an acyloxy-substituted alkoxy group having 7 to 25 carbon atoms is preferable.

  The acyl group is represented by —CO—R, the acyloxy group is represented by —O—CO—R, and R is an aliphatic group (alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkynyl group, substituted alkynyl group) or aromatic. Group (aryl group, substituted aryl group). R is preferably an aliphatic group, and more preferably an alkyl group or an alkenyl group.

p is an integer of 1-10. It is particularly preferable that p is 1 or 2. C _p H _2p means a chain alkylene group which may have a branched structure. C _p H _2p is preferably a linear alkylene group (— (CH ₂ ) _p —).

  Among the compounds represented by the formula (II), a compound represented by the following formula (II ′) is preferable.

In the formula (II ′), the same symbols as those in the formula (II) have the same meaning, and the preferred ranges are also the same. L ²⁵ has the same meaning as L ²⁴ , and the preferred range is also the same. L ²⁴ and L ²⁵ are preferably —O—CO— or —CO—O—, L ²⁴ is preferably —O—CO—, and L ²⁵ is preferably —CO—O—.

R ²³ , R ²⁴ and R ²⁵ are each an alkyl group having 1 to 12 carbon atoms (more preferably 1 to 6, more preferably 1 to 3). n ₂₃ is 0-4, n ₂₄ is 1 to 4, and n ₂₅ represents 0 to 4. In n ₂₃ and n ₂₅ is 0, n ₂₄ is preferably a 1-4 (more preferably 1-3).

  Specific examples of the compound represented by the general formula (II) include compounds described in [0058] to [0061] in JP-A-2006-113500.

Other specific examples of the compound represented by the general formula (II) include the following compounds. However, the anion (X ⁻ ) was omitted in the following formula.

Specific examples of the compound represented by the general formula (II ′) are shown below. However, the anion (X ⁻ ) was omitted in the following formula.

  The pyridinium derivative of the formula (II) is generally obtained by alkylating the pyridine ring (Menstokin reaction).

  The preferred range of the content of the pyridinium derivative in the composition for forming the retardation layer varies depending on its use, but in the composition (liquid crystalline composition excluding the solvent when prepared as a coating liquid), It is preferable that it is 0.005-8 mass%, and it is more preferable that it is 0.01-5 mass%.

[Air interface side vertical alignment agent]
As the air interface side vertical alignment agent in the present invention, the following fluorine-based polymer or a fluorine-containing compound represented by the general formula (III) is preferably used.

  Fluoropolymer: a copolymer containing a repeating unit derived from a fluoroaliphatic group-containing monomer and a repeating unit represented by the following formula (IV)

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

Fluorine-containing compound represented by the following formula (III):
(III) (R ⁰ ) _m -L ^0- (W) _n
In the formula, R ⁰ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and m represents an integer of 1 or more. A plurality of R ⁰ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ⁰ represents a (m + n) -valent linking group, W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or phosphonoxy {—OP (═O) (OH) ₂ } Or a salt thereof, and n represents an integer of 1 or more.

First, the fluorine polymer will be described.
The fluoropolymer usable in the present invention includes a fluoroaliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and their It contains one or more hydrophilic groups selected from the group consisting of salts. The types of polymers are described in “Revised Chemistry of Polymer Synthesis” (Takayuki Otsu, published by Kagaku Dojin Co., 1968), pages 1-4, for example, polyolefins, polyesters, polyamides, polyimides. , Polyurethanes, polycarbonates, polysulfones, polycarbonates, polyethers, polyacetals, polyketones, polyphenylene oxides, polyphenylene sulfides, polyarylates, PTFEs, polyvinylidene fluorides, cellulose derivatives, etc. It is done. The fluoropolymer is preferably a polyolefin.

  The fluorine-based polymer is a polymer having a fluoroaliphatic group in the side chain. The fluoroaliphatic group preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The aliphatic group may be linear or cyclic, and when it is linear, it may be linear or branched. Of these, a linear fluoroaliphatic group having 6 to 10 carbon atoms is preferable. The degree of substitution with fluorine atoms is not particularly limited, but 50% or more of hydrogen atoms in the aliphatic group are preferably substituted with fluorine atoms, and more preferably 60% or more are substituted. The fluoroaliphatic group is contained in a side chain bonded to the polymer main chain via an ester bond, an amide bond, an imide bond, a urethane bond, a urea bond, an ether bond, a thioether bond, an aromatic ring, or the like. One of the fluoroaliphatic groups is derived from a fluoroaliphatic compound produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). 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 (example in Scheme-1). showed that).

  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.

  Specific examples of the monomer that can be used in the production of the fluoropolymer that can be used in the present invention include compounds described in paragraphs [0075] to [0081] of JP-A-2006-113500. It is not limited at all by these specific examples.

  One aspect of a fluoropolymer that can be used in the present invention is a copolymer having a repeating unit derived from a fluoroaliphatic group-containing monomer and a repeating unit containing a hydrophilic group represented by the following formula (IV): It is a coalescence.

In the above formula (IV), R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent. Q represents 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. L represents an arbitrary group selected from the following linking group group, or a divalent linking group formed by combining two or more thereof.
(Linked group group)
Single bond, —O—, —CO—, —NR ^b — (R ^b represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ^c ) — (R ^c represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.

In formula (IV), 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)
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a 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 2 to 12 carbon atoms, Particularly preferred are alkenyl groups having 2 to 8 carbon atoms, such as vinyl group, aryl group, 2-butenyl group and 3-pentenyl group), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferred). Is an alkynyl group having 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl group and 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, and a naphthyl group. Aralkyl groups (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as benzyl group, phenethyl group, 3- Phenylpropyl group and the like), a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, Unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.),

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). An alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group), acyloxy A group (preferably an acyloxy group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms such as an acetoxy group and a benzoyloxy group), an acylamino group (preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-10 carbon atoms. A silamino group, for example, an acetylamino group, a benzoylamino group, and the like, an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms). An alkoxycarbonylamino group, for example, a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, and particularly preferably 7 to 12 carbon atoms). Aryloxycarbonylamino group, for example, phenyloxycarbonylamino group and the like, sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms). 12 sulfonylamino groups such as methanesulfonyl And sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as sulfamoyl group). Group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group and the like), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably carbon number). 1 to 12 carbamoyl groups, for example, unsubstituted carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group and the like),

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is C6-C20, More preferably, it is C6-C16, Most preferably, it is C6-C12 arylthio group, for example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, particularly preferably a sulfonyl group having 1 to 12 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 20, more A sulfinyl group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms is preferable. Zensulfinyl group and the like), 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, for example, an unsubstituted ureido group , Methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms). Yes, for example, diethyl phosphoric acid amide group, phenyl phosphoric acid amide group, etc.), 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, heterocyclic group (preferably having a carbon number of 1 to 0, more preferably a heterocyclic group of 1 to 12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group , Piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably A silyl group having 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.

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), or a group represented by -LQ described later. It is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Particularly preferred are a hydrogen atom and an alkyl group having 1 to 2 carbon atoms. 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.

L represents a divalent linking group selected from the above linking group group, or a divalent linking group formed by combining two or more thereof. In the linking group group, R ^{b in} —NR ^b — represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom or an alkyl group. R ^c in —PO (OR ^c ) — represents an alkyl group, an aryl group or an aralkyl group, and preferably an alkyl group. When R ^b and R ^c 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 contains a single bond, —O—, —CO—, —NR ^b —, —S—, —SO ₂ —, an alkylene group or an arylene group, and —CO—, —O—, —NR ^b- , an alkylene group or an arylene group is particularly preferred. When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Specific examples of particularly preferred alkylene groups include methylene, ethylene, trimethylene, tetrabutylene, hexamethylene groups and the like. When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene and naphthalene groups. When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. 7-16. 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 those similar to the substituents exemplified above as the substituents for R ^{1 to} R ³ .
Specific examples of L include the structures described in paragraphs [0090] to [0091] of JP-A-2006-113500, but the present invention is not limited to these specific examples.

  In the formula (IV), 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, trimethyl). Benzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups (salts) Examples of the cation that forms are the same as those described above for the carboxyl group). A carboxyl group, a sulfo group, and a phospho group are more preferable, and a carboxyl group or a sulfo group is particularly preferable.

  The fluoropolymer may contain one type of repeating unit represented by the formula (IV) or 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 following monomer group.

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 and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(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 (number of added polyoxyethylene: 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) Diesters of unsaturated polycarboxylic acids Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;

(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and its derivatives 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-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, 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 .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline, etc.

  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. In the fluoropolymer, the amount of the repeating unit represented by the formula (IV) is preferably 0.5% by mass or more, and preferably 1 to 20% by mass of the total amount of the constituent monomers of the fluoropolymer. More preferably, it is 1 to 10% by mass. Since the above-mentioned mass percentage easily varies in a preferable range depending on the molecular weight of the monomer used, the content of the repeating unit represented by the formula (IV) is expressed by the number of moles of the functional group per unit mass of the polymer. Can be defined accurately. When this notation is used, the preferable amount of the hydrophilic group (Q in the formula (IV)) contained in the fluoropolymer is 0.1 mmol / g to 10 mmol / g, and the more preferable amount is 0. .2 mmol / g to 8 mmol / g.

  The fluorine-based polymer used in the present invention preferably has a mass average molecular weight of 1,000,000 or less, more preferably 500,000 or less, and still more preferably 100,000 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 preferred 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 hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (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) Beam, such as potassium sulphate). 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 include 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 about 01 mol% to 50 mol%, preferably 0.05 mol% to 30 mol%, particularly preferably 0.08 mol% to 25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization is to 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 may be added separately from the monomer.

  The fluoropolymer of the present invention preferably has a polymerizable group as a substituent in order to fix the alignment state of the discotic liquid crystal compound.

  Specific examples of the fluoroaliphatic group-containing copolymer preferably used in the present invention as a fluorine-based polymer include the compounds described in paragraphs [0110] to [0114] of JP-A-2006-113500. Is not limited by these specific examples.

  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 preferred range of the content of the fluoropolymer in the composition varies depending on the application, but when used for forming the retardation layer, in the composition (a composition excluding the solvent in the case of a coating solution), The amount is preferably 0.005 to 8% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.05 to 3% by mass. If the addition amount of the fluorine-based polymer is less than 0.005% by mass, the effect is insufficient, and if it exceeds 8% by mass, the coating film cannot be sufficiently dried, or the performance as an optical film (for example, letter Adversely affects the uniformity of the foundation.

Next, the fluorine-containing compound represented by the formula (III) will be described.
(III) (R ⁰ ) _m -L ^0- (W) _n
In the formula (III), R ⁰ functions as a hydrophobic group of the fluorine-containing compound. The alkyl group represented by R ⁰ is a substituted or unsubstituted alkyl group, which may be linear or branched, preferably an alkyl group having 1 to 20 carbon atoms, more preferably Is an alkyl group of 4 to 16, particularly preferably an alkyl group of 6 to 16. As the substituent, any of the substituents exemplified as the substituent group D described later can be applied. The alkyl group having a CF ₃ group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and particularly preferably 4 to 8. The alkyl group having a CF ₃ group at the terminal is an alkyl group in which part or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with the substituents exemplified as the substituent group D described later. The alkyl group having a CF ₂ H group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and particularly preferably 4 to 8. The alkyl group having a CF ₂ H group at the terminal is an alkyl group in which some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with the substituents exemplified as the substituent group D described later. Examples of an alkyl group having a CF ₃ group at the terminal represented by R ⁰ or an alkyl group having a CF ₂ H group at the terminal are shown below.

R1: n-C ₈ F _{17-
R2: n-C 6 F 13} -
_{R3: n-C 4 F 9} -
_{R4: n-C 8 F 17} - (CH 2) 2 -
_{R5: n-C 6 F 13} - (CH 2) 2 -
_{R6: n-C 4 F 9} - (CH 2) 2 -
_{R7: H- (CF 2) 8} -
_{R8: H- (CF 2) 6} -
_{R9: H- (CF 2) 4} -
_{R10: H- (CF 2) 8} - (CH 2) -
R11: H— (CF ₂ ) ₆ — (CH ₂ ) —
_{R12: H- (CF 2) 4} - (CH 2) -

In the formula (III), the (m + n) -valent linking group represented by L ⁰ is an alkylene group, an alkenylene group, an aromatic group, a heterocyclic group, —CO—, —NR— (R has 1 carbon atom) A linking group in which at least two groups selected from the group consisting of —O—, —S—, —SO—, and —SO ₂ — are combined.

In formula (III), W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. . The preferred range of W is the same as Q in formula (IV).

  Among the fluorine-containing compounds represented by the formula I (III), compounds represented by the following formula (III) -a or formula (III) -b are preferable.

In formula (III) -a, R ⁴ and R ⁵ each represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and R ⁴ and R ⁵ are simultaneously It is not an alkyl group. W ¹ and W ² are each a hydrogen atom, a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or An alkyl group, an alkoxy group or an alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent is represented, but W ¹ and W ² are not simultaneously hydrogen atoms.

Formula ^{(III) -b (R 6 -L} 2 -) m2 (Ar 1) -W 3

In formula (III) -b, R ⁶ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, m2 represents an integer of 1 or more, R ⁶ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ² represents an alkylene group, an aromatic group, —CO—, —NR— (R is an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —S—, —SO—, —SO. _2- represents a divalent linking group selected from the group consisting of combinations thereof, and a plurality of L ² may be the same or different. Ar ¹ represents an aromatic hydrocarbon ring or an aromatic heterocycle, W ³ represents 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, or an alkyl group, an alkoxy group, or an alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group as a substituent.

First, the formula (III) -a will be described.
R ⁴ and R ⁵ are synonymous with R ⁰ in the formula (III), and their preferred ranges are also the same. The carboxyl group (—COOH) represented by W ¹ and W ² 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 is It is synonymous with W in Formula (III), and its preferable range is also the same. The alkyl group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ^{1 or} W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. It is an alkyl group, More preferably, it is a 1-8 alkyl group, Most preferably, it is a 1-3 alkyl group. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, sulfo group, or phosphonoxy group. It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent may be substituted with any other substituent, and the substituent is any of the substituents exemplified as the substituent group D described later. Can be applied. The alkoxy group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ¹ and W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. An alkoxy group, more preferably an alkoxy group of 1 to 8, and particularly preferably an alkoxy group of 1 to 4. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, a sulfo group, or a phosphonoxy group. It is synonymous with the parent carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as Substituent Group D described later can be applied as the substituent. . The alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ^{1 or} W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. More preferably 1 to 8 alkylamino groups, and particularly preferably 1 to 4 alkylamino groups. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group may have at least one carboxyl group, a sulfo group, or a phosphonoxy group. Examples of the carboxyl group, the sulfo group, and the phosphonoxy group include the above-described formula ( It is synonymous with the carboxyl group represented by W in III), a sulfo group, and a phosphonoxy group, and its preferable range is also the same. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as Substituent Group D described later is applied as the substituent. it can.

W ¹ and W ² are particularly preferably each a hydrogen atom or (CH ₂ ) _n SO ₃ M (n represents 0 or 1). M represents a cation, but M may not be present when the charge is 0 in the molecule. As cations represented by M, for example, protonium ions, alkali metal ions (lithium ions, sodium ions, potassium ions, etc.), alkaline earth metal ions (barium ions, calcium ions, etc.), ammonium ions and the like are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

Next, the formula (III) -b will be described.
R ⁶ has the same meaning as R ⁰ in the formula (III), and its preferred range is also the same. L ² is preferably an alkylene group having 1 to 12 carbon atoms, an aromatic group having 6 to 12 carbon atoms, —CO—, —NR—, —O—, —S—, —SO—, —SO ₂ — and Represents a linking group having a total carbon number of 0 to 40 consisting of a combination thereof, particularly preferably an alkylene group having 1 to 8 carbon atoms, a phenyl group, —CO—, —NR—, —O—, —S—, —SO. ₂ represents a linking group having 0 to 20 carbon atoms and a combination thereof. Ar ¹ preferably represents an aromatic hydrocarbon ring having 6 to 12 carbon atoms, particularly preferably a benzene ring or a naphthalene ring. As a carboxyl group (—COOH) represented by W ³ 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, or a substituent A carboxyl group, a sulfo group, an alkyl group having a phosphonoxy group, an alkoxy group, or an alkylamino group is a carboxyl group (—COOH) represented by W ¹ and W ² in the above formula (III) -a or a salt thereof, sulfo Group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or an alkyl group, an alkoxy group, or an alkyl having a carboxyl group, a sulfo group, or a phosphonoxy group as a substituent. It is synonymous with an amino group and its preferable range is also the same.

W ³ is preferably a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a carboxyl group (—COOH) or a salt thereof or a sulfo group (—SO ₃ H) as a substituent. Or an alkylamino group having a salt thereof, particularly preferably SO ₃ M or CO ₂ M. M represents a cation, but M may not be present when the charge is 0 in the molecule. As cations represented by M, for example, protonium ions, alkali metal ions (lithium ions, sodium ions, potassium ions, etc.), alkaline earth metal ions (barium ions, calcium ions, etc.), ammonium ions and the like are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

  In the present specification, the substituent group D includes 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. , Ethyl group, isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 carbon atoms) -20, 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 allyl group, a 2-butenyl group, and a 3-pentenyl group), alkynyl A group (preferably an alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, And aryl groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms). Group, p-methylphenyl group, naphthyl group and the like), substituted or unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably 0 to 6 carbon atoms). An amino group, for example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group and the like),

  An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). An aryloxy group (preferably an aryloxy group having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyloxy group and a 2-naphthyloxy group. ), An acyl group (preferably an acyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, an acetyl group, a benzoyl group, a formyl group, a pivaloyl group. An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 carbon atoms). 12 is an alkoxycarbonyl group, and examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group), an aryloxycarbonyl group (preferably having a carbon number of 7 to 20, more preferably a carbon number of 7 to 16, and particularly preferably a carbon number). An aryloxycarbonyl group having 7 to 10 carbon atoms, such as a phenyloxycarbonyl group, an acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 2 carbon atoms). 10 acyloxy groups such as an acetoxy group and a benzoyloxy group)

  An acylamino group (preferably an acylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as an acetylamino group and a benzoylamino group), alkoxycarbonyl An amino group (preferably an alkoxycarbonylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), aryloxy Carbonylamino group (preferably an aryloxycarbonylamino group having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group) Sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferred Or a sulfonylamino group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include a methanesulfonylamino group and a benzenesulfonylamino group, and a sulfamoyl group (preferably having a carbon number of 0 to 20). More preferably, it is a sulfamoyl group having 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group. ), A carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. For example, an unsubstituted carbamoyl group, a methylcarbamoyl group, diethylcarbamoyl group Group, phenylcarbamoyl group, etc.),

  An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is C6-C20, More preferably, it is C6-C16, Most preferably, it is C6-C12 arylthio group, for example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, particularly preferably a sulfonyl group having 1 to 12 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 20, more A sulfinyl group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms is preferable. Zensulfinyl group and the like), 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, for example, an unsubstituted ureido group , Methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms). Yes, for example, diethyl phosphoric acid amide group, phenyl phosphoric acid amide group, etc.), 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, heterocyclic group (preferably having a carbon number of 1 to 0, more preferably a heterocyclic group of 1 to 12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group , Piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably A silyl group having 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. Further, when two or more substituents are present, they may be the same or different. If possible, they may be bonded to each other to form a ring.

  In addition, the fluorine-containing compound of the present invention preferably has a polymerizable group as a substituent in order to fix the alignment state of the discotic liquid crystal compound.

  Specific examples of the fluorine-containing compound represented by the formula (III) that can be used in the present invention include compounds described in paragraphs [0136] to [0140] of JP-A-2006-113500. Is not limited by these specific examples.

  The preferred range of the content of the fluorine-containing compound in the composition varies depending on its use, but when used for forming the retardation layer, in the composition (a composition excluding the solvent in the case of a coating solution), The amount is preferably 0.005 to 8% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.05 to 3% by mass.

[Polymerization initiator]
The aligned (preferably vertically aligned) liquid crystal compound is fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. Light irradiation for polymerization of discotic liquid crystalline molecules is preferably performed using ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the retardation layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

[Other additives for retardation layer]
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. 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 molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specifically, for example, compounds described in paragraphs [0028] to [0056] in JP-A No. 2001-330725, and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212 are described. The compound of this is mentioned.

The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.
The discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

[Coating solvent]
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), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

[Coating method]
The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method). Especially, when forming the said phase difference layer, it is preferable to apply | coat using a wire bar coating method, and it is preferable that the rotation speed of a wire bar satisfy | fills following formula.
0.6 <(W × (R + 2r) × π) / V <1.4
[W: Number of rotations of wire bar (rpm), R: Diameter of core of bar (m), r: Diameter of wire (m), V: Conveying speed of support (m / min)]
The range of (W × (R + 2r) × π) / V is more preferably 0.7 to 1.3, and still more preferably 0.8 to 1.2.

  A die coating method is preferably used for forming the retardation layer, and a coating method using a slide coater or a slot die coater is particularly preferable.

2. 1st and 2nd polarizing film There is no restriction | limiting in particular about the polarizing film utilized for this invention. As the polarizing film, any of an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film may be used. The iodine-based polarizing film and the dye-based polarizing film are generally produced using a polyvinyl alcohol-based (hereinafter referred to as “PVA-based”) film. The absorption axis of the polarizing film corresponds to the stretching direction of the film. Accordingly, the polarizing film stretched in the longitudinal direction (transport direction) has an absorption axis parallel to the longitudinal direction, and the polarizing film stretched in the lateral direction (perpendicular to the transport direction) is perpendicular to the longitudinal direction. Has an absorption axis.

  In recent years, thinning is required for liquid crystal display devices, and thinning is also required for polarizing films used therefor. An example of a method for forming a thin polarizing film is as follows. A PVA-based resin layer is formed by coating on a resin substrate (for example, a thermoplastic resin substrate), and the PVA-based resin layer formed on the resin substrate is stretched together with the resin substrate to be subjected to a dyeing process. . By this method, a very thin polarizing film can be manufactured compared with the polarizing film obtained by the conventional method.

  Japanese Patent No. 4804588 discloses a two-step stretching process in which an amorphous ester thermoplastic resin base material and a PVA resin layer coated and formed thereon are integrally formed by air-assisted stretching and boric acid-water stretching. And a method of subjecting the PVA resin layer to a dyeing treatment with a dichroic dye. By this method, a polarizing film having a thickness of 10 μm or less can be produced.

  The polarizing film generally has a protective film. In the present invention, the optical compensation film can function as a protective film for the first polarizing film, and is preferably disposed with the first retardation region side set to the first polarizing film side. It is preferable to arrange a protective film on the other surface of the first polarizing film to which the optical compensation film is adhered. There is no restriction | limiting in particular about the protective film arrange | positioned outside a polarizing film. Cellulose acylate films, cyclic olefin polymer films, polyvinyl alcohol films, polypropylene films, polycarbonate films, norbornene films, acrylic films, PET films and the like can be used. Among these, it is preferable to use a cellulose acylate film.

  It is preferable to laminate a protective film on both surfaces of the second polarizing film. In particular, a protective film disposed on the liquid crystal cell side is required to have low Re and low Rth from the viewpoint of improving viewing angle contrast. Specifically, the absolute value | Re (550) | of Re (550) is 10 nm or less, and the absolute value | Rth (550) | of Rth (550) is 30 nm or less. Ideally, both | Re (550) | and | Rth (550) | are 0 nm. Further, from the viewpoint of reducing the color shift that occurs in the oblique direction, Re of the protective film preferably has a small wavelength dispersion, and specifically, | Re (400) −Re (700) | is 10 nm or less. , And | Rth (400) -Rth (700) | are 35 nm or less, and ideally, | Re (400) -Re (700) | and | Rth (400) -Rth (700) | is there.

  In order to achieve low Re and low Rth, it is preferable to reduce the thickness of the film. On the other hand, if the thickness is too thin, the function as a protective film becomes insufficient and the durability of the polarizing film decreases. As a result, the durability of the liquid crystal display device decreases. From these viewpoints, the thickness of the protective film for the second polarizing film and disposed on the liquid crystal cell side is preferably 10 to 90 μm, and more preferably 30 to 80 μm.

  When thinning the film in the solution casting method, the dope is cast on a solution casting process (for example, a metal support) and then peeled off to transport a highly volatile film. In the process of drying, the rigidity of the thin film decreases, making it difficult to transport and handle. Therefore, it is preferable to cast a plurality of dopes including a dope for forming a release film, temporarily increase the thickness, and improve conveyance and handling properties. In this method, a laminated film is produced, but before the actual use, the release film is peeled off from the laminated film and can be used as a thin film.

  Examples of the film having the above-mentioned thickness and capable of achieving the above-described optical characteristics and suitably used as a protective film for the second polarizing film include a cellulose acylate film, a cyclic olefin polymer film, and an acrylic film. Polymer film is included. Among acrylic polymer films, an acrylic polymer film containing an acrylic polymer containing at least one unit selected from a lactone ring unit, a maleic anhydride unit, and a glutaric anhydride unit is optically isotropic. This is preferable because of its high properties. The details of the acrylic polymer film are described in JP-A-2008-9378 and can be referred to. Each example is the same as the examples of the cellulose acylate film, the cyclic olefin polymer film, and the acrylic polymer film that can be used as the first transparent film described in JP2010-33041A.

  The preferable manufacturing method of a polarizing plate includes the process of laminating | stacking continuously two sheets of protective films and a polarizing film in a respectively long state. The long polarizing plate is cut in accordance with the screen size of the image display device used. In addition, about the 1st polarizing film, the said optical compensation film is bonded on one surface. The polarizing plate thus produced is arranged with the optical compensation film on the liquid crystal cell side. Any of the first and second retardation regions constituting the optical compensation film may be arranged on the polarizing film side. However, in terms of adhesion to the polarizing film, a polymer film is arranged. In a mode in which the first retardation region is bonded to the polarizing film, a polymer film is disposed on the retardation layer formed using a discotic liquid crystal compound, and the polymer film is bonded to the polarizing film. It is preferable to do this. The polymer film preferably has a low Re and a low Rth, and examples of usable polymer films are the same as the examples of polymer films suitably used as the protective film (liquid crystal cell side protective film) of the second polarizing film. It is.

3. Liquid Crystal Cell The liquid crystal display device of the present invention has IPS and FFS type liquid crystal cells. These horizontal alignment types are described in various documents, and any configuration can be employed in the present invention. It can be obtained in any of the display devices. IPS type liquid crystal display devices are disclosed in, for example, JP2003-15160, JP2003-75850, JP2003-295171, JP200412730, JP200412731, JP2005-106967, JP-A-2005-134914, JP-A-2005-241923, JP-A-2005-284304, JP-A-2006-189758, JP-A-2006-194918, JP-A-2006-220680, JP-A-2007-140353, JP 2007-178904, JP 2007-293290, JP 2007-328350, JP 2008-3251, JP 2008-39806, JP 2008-40291, JP 2008-65196, JP 2008-76849, JP 2008-96815 It can be used those described in JP.

  An FFS type (hereinafter also referred to as FFS mode) liquid crystal cell has a counter electrode and a pixel electrode. These electrodes are made of a transparent material such as ITO, and are narrower than the distance between the upper and lower substrates, etc., and are wide enough to drive all the liquid crystal molecules placed on the electrodes. Has been. With this configuration, in the FFS mode, it is possible to obtain an aperture ratio that is improved compared to the IPS mode. Further, since the electrode portion is light transmissive, it is possible to obtain a transmittance that is improved compared to the IPS mode. Regarding the FFS mode liquid crystal cell, for example, refer to the descriptions in Japanese Patent Laid-Open Nos. 2001-100193, 2002-14374, 2002-182230, 2003-131248, and 2003-233083. it can.

  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.

1. Preparation of Film (1) Preparation of Film (Cellulose Acylate Film Having Aromatic Groups) 1-3 and 1 ′ The following composition is put into a mixing tank, stirred to dissolve each component, and further at 90 ° C. After heating for about 10 minutes, each cellulose acylate solution (hereinafter sometimes referred to as a dope) was prepared by filtering through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm.

―――――――――――――――――――――――――――――――――――――――
(Cellulose acylate A solution composition)
―――――――――――――――――――――――――――――――――――――――
Cellulose acylate A 100.0 parts by mass (degree of substitution of benzoyl group: 0.86; degree of substitution of acetyl group: 1.76)
Dichloromethane 462.0 parts by mass ―――――――――――――――――――――――――――――――――――――――

―――――――――――――――――――――――――――――――――――――――
(Cellulose acylate B solution composition)
―――――――――――――――――――――――――――――――――――――――
Cellulose acylate B 100.0 parts by mass (degree of substitution of benzoyl group: 0.78; degree of substitution of acetyl group: 1.76)
Dichloromethane 462.0 parts by mass ―――――――――――――――――――――――――――――――――――――――

Each obtained dope was cast using a metal band casting machine and dried, and then the film was peeled off from the band by a peeling drum.
The film was stretched in the tenter zone by fixed-end uniaxial stretching in the film transport direction (MD) at the temperatures and stretch ratios shown in the following table. Next, at the same temperature, the film was stretched in the tenter zone by fixed-end uniaxial stretching in the width direction (TD) at the temperatures and stretch ratios shown in the following table. In this way, a biaxial stretching process was performed to prepare cellulose acylate films.
The cast film thickness was adjusted so that the film thickness after stretching and drying was the film thickness described in the following table.

  The thickness of the film produced as described above was changed and adjusted to the desired Re and Rth listed in the table below, and the films (cellulose acylate films having aromatic groups) 1 to 3 and 1 ' Each was produced.

(2) Preparation of Film 4 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 having an acetylation degree of 60.7 to 61.1% 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) 336 parts by weight Methanol (second solvent) 29 parts by mass 1-butanol (third solvent) 11 parts by mass ――――――――――――――――――――――――――――― ――――――――――

  In another mixing tank, 16 parts by mass of the following retardation increasing agent (A), 92 parts by mass of methylene chloride and 8 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution. A dope was prepared by mixing 474 parts by mass of the cellulose acetate solution with 25 parts by mass of the retardation increasing agent solution and stirring sufficiently. The addition amount of the retardation increasing agent was 6.0 parts by mass with respect to 100 parts by mass of cellulose acetate.

  The obtained dope was cast using a band stretching machine. After the film surface temperature on the band reaches 40 ° C., the film is dried with warm air of 70 ° C. for 1 minute, and the film from the band is dried with 140 ° C. drying air for 10 minutes, and the residual solvent amount is 0.3 mass%. A cellulose acetate film was prepared. The obtained long cellulose acetate film had a width of 1490 mm and a thickness of 60 μm. This cellulose acylate film was used as the film 4.

(3) Preparation of Film 5 A commercially available triacetyl cellulose film “Fujitac TD80UL” (manufactured by Fuji Film Co., Ltd.) was prepared. This commercially available triacetyl cellulose film was used as the film 5.

(4) Preparation of Film 6 A commercially available triacetyl cellulose film “Z-TAC” (manufactured by FUJIFILM Corporation) was prepared. This commercially available triacetyl cellulose film was used as the film 6.

(5) Preparation of Film 7 A commercially available polycarbonate film “Pure Ace R” (manufactured by Teijin Chemicals Ltd.) was prepared and used as the film 7.

(6) Preparation of film 8 Preparation of acrylic polymer containing maleic anhydride units:
According to “(b) heat-resistant acrylic resin” described in JP-A-2007-113109, [0050], a resin having 10 mol% maleic anhydride, 16 mol% styrene, and 74 mol% methyl methacrylate was synthesized. The Tg was 112 ° C.

The prepared acrylic polymer was dried with a vacuum dryer at 90 ° C. so that the water content was 0.03% or less, and then 0.3% by weight of a stabilizer (Irganox 1010 (manufactured by Ciba Geigy Co., Ltd.)) was added. Under a nitrogen stream at 0 ° C., a biaxial kneading extruder with a vent was used to extrude into water to form a strand, which was then cut to obtain a pellet having a diameter of 3 mm and a length of 5 mm.
These pellets were dried with a 90 ° C. vacuum dryer to a water content of 0.03% or less, and then kneaded and extruded at a temperature under the following conditions using a single-screw kneading extruder. After this, a 300 mesh screen filter was installed between the extruder and the gear pump. Then, after passing through a gear pump under the following conditions, the melt was extruded from a die through a leaf disk filter having a filtration accuracy of 7 μm, and cast under the following conditions. The “differential pressure before and after the gear pump” in the following conditions is a value obtained by subtracting the rear pressure from the front pressure, and in “the gap between the melt landing point and the middle point of the touch roll / cast roll”, positive is a touch. On the roll side, negative indicates landing on the cast roll side.
Thereafter, a melt (molten resin) was extruded onto a triple cast roll. At this time, the touch roll was brought into contact with the most upstream cast roll (chill roll) at the surface pressure described in the following conditions. The touch roll described in Example 1 of JP-A No. 11-235747 (the one described as a double holding roll, except that the thickness of the thin metal outer cylinder was 2 mm) was used at Tg-5 ° C. The touch pressure described in the conditions was used. In addition, the temperature of the triple cast roll including the chill roll has a temperature difference (cast roll temperature-touch roll temperature) described in the following conditions for the uppermost cast roll (first roll) in contact with the touch roll. I did it. Furthermore, the next cast roll (second roll) was a first roll at -5 ° C, and the next cast roll (third roll) was a first roll at -10 ° C.
Then, after trimming both ends (5 cm each of the full width) immediately before winding, thicknessing (knurling) with a width of 10 mm and a height of 20 μm was applied to both ends. Further, the film-forming width was 1.5 m, and the film was wound up 3000 m at a film-forming speed of 30 m / min. The thickness of the unstretched film after film formation was 60 μm.
The touch roll was brought into contact with the most upstream cast roll at the surface pressure described in the following conditions. Below, screw temperature difference, discharge amount, differential pressure before and after the gear pump, front and back temperature difference of the melt on the cast roll, temperature difference between the cast roll and touch roll, deviation between the melt landing point and the middle point of the touch roll / cast roll, The touch roll pressure, film formation width variation, film formation width variation, and film formation width average are shown.
(conditions)
Screw temperature difference (outlet-inlet): 30 ° C
Discharge rate: 200kg / hr
Differential pressure before and after gear pump (front-rear): -3 MPa
Cast roll temperature-touch roll temperature: -5 ° C
Melt landing point-Touch roll / cast roll midpoint deviation: -3mm
Touch pressure of the touch roll: 0.1 MPa
Film formation width fluctuation: 6%
Average film forming width: 25 m

  The acrylic polymer film produced as described above was used as the film 8.

(7) Preparation of Film 9 Using TOPAS # 6013 pellets (Tg = 136 ° C.) of Polyplastics Co., Ltd., dried at 110 ° C. for 2 hours or more and extruded using a single screw kneading extruder. At this time, a screen filter, a gear pump, and a leaf disk filter were arranged in this order between the extruder and the die, and these were connected by a melt pipe. This was extruded from a die having an extrusion temperature (discharge temperature) of 260 ° C. and a width of 1900 mm and a lip gap of 1 mm.
Thereafter, the molten resin was extruded into the center portion of the chill roll and touch roll. At this time, the chill roll is a 2000 mm wide and 400 mm diameter HCr plated metal roll, and the touch roll is 1700 mm wide and 350 mm in diameter as described in Example 1 of JP-A-11-235747 (double What has been described as a restraining roll, except that the thickness of the thin metal outer cylinder was 2 mm).

Using these rolls, the temperature of both the touch roll and the chill roll was Tg-5 ° C. The film forming atmosphere was 25 ° C. and 60%.
Then, after trimming both ends (5 cm each of the full width) immediately before winding, thicknessing (knurling) with a width of 10 mm and a height of 20 μm was applied to both ends. The film forming width was 1540 mm and the film was wound up by 450 m.
This film was used as film 9.

(8) Preparation of Polymer Film 10 A cyclic olefin polymer film mounted on a Toshiba (37H3000) liquid crystal TV was peeled off and used as the film 10.

2. Production of optical compensation film (1) Preparation of support Each of the above films was used as a support.

The following alkali saponification treatment was performed on the cellulose acylate film.
(Alkaline saponification treatment)
Each cellulose acylate film is passed through a dielectric heating roll having a temperature of 60 ° C. and the film surface temperature is raised to 40 ° C., and then an alkali solution having the composition shown below is applied to one side of the film using a bar coater. The coating was applied at a coating amount of 14 mL / m ² and transported for 10 seconds under a steam far infrared heater manufactured by Noritake Co., Ltd., heated to 110 ° C. Subsequently, 3 mL / m ^{2 of} pure water was applied using the same bar coater. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then the sheet was transported to a drying zone at 70 ° C. for 10 seconds and dried to prepare an alkali saponified cellulose acylate film.
―――――――――――――――――――――――――――――――――――――――
Alkaline solution composition:
―――――――――――――――――――――――――――――――――――――――
Potassium hydroxide 4.7 parts by weight Water 15.8 parts by weight Isopropanol 63.7 parts by weight Surfactant SF-1: C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) ₂₀ H 1.0 part by weight Propylene glycol 14. 8 parts by mass ―――――――――――――――――――――――――――――――――――――――

  Films other than the cellulose acylate film were subjected to corona discharge treatment using a solid state corona treatment machine 6KVA (manufactured by Pillar Co., Ltd.).

(Formation of alignment film)
An alignment film coating solution having the following composition was continuously applied to each long film saponified as described above with a # 14 wire bar. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 100 ° C. for 120 seconds.
―――――――――――――――――――――――――――――――――――――――
Composition of alignment film coating solution:
―――――――――――――――――――――――――――――――――――――――
Denatured polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight Photopolymerization initiator (Irgacure 2959, manufactured by Ciba Japan) 0.3 parts by weight ―――――――――――――――――――――――――――――――

(Formation of retardation layer 1 containing discotic liquid crystalline compound)
The alignment film thus prepared was continuously rubbed. At this time, the longitudinal direction of the long film and the transport direction were parallel, and the rotation axis of the rubbing roller was orthogonal to the film longitudinal direction.

A coating solution containing a discotic liquid crystal compound having the following composition was continuously applied to the formed alignment film with a # 2.7 wire bar. The conveyance speed (V) of the film was 36 m / min. In order to dry the solvent of the coating solution and to mature the orientation of the discotic liquid crystal compound, the coating liquid was heated with warm air at 120 ° C. for 90 seconds. Subsequently, UV irradiation was performed at 80 ° C., the orientation of the liquid crystal compound was fixed, the retardation layer 1 was formed, and an optical compensation film was obtained.
Composition of coating liquid for forming retardation layer 1 The following discotic liquid crystal compound 100 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Japan) 3 parts by mass sensitizer (Kayacure DETX, Nippon Kayaku Co., Ltd.) 1 part by mass The following pyridinium salt 1 part by mass The following fluoropolymer (FP1) 0.4 part by mass Methyl ethyl ketone 252 parts by mass

  The direction of the slow axis was orthogonal to the rotation axis of the rubbing roller. That is, the slow axis was parallel to the longitudinal direction of the support. Separately, instead of using each film as a support, a layer containing a discotic liquid crystal compound is formed using glass as a substrate, and Re (0 °), Re (40 °), and Re (−40 °) are set to KOBRA21. When measured using ADH, they were 140.3 nm, 126.9 nm, and 126.7 nm, respectively. (Re (°) indicates the incident angle with the normal direction of the sample surface being 0 °.) From these results, the disc surface of the discotic liquid crystal molecules has an average inclination angle of 90 ° with respect to the film surface. It was confirmed that the liquid crystal was aligned perpendicular to the film surface. The wavelength dispersion of the formed retardation layer was Re (450) / Re (550) of 1.10 and Re (650) / Re (550) of 0.96.

(Formation of retardation layer 2 containing discotic liquid crystalline compound)
An alignment film was formed on the surface of each film in the same manner as described above.
A coating liquid containing a discotic liquid crystal compound having the following composition was continuously applied onto the formed alignment film with a # 4.0 wire bar. The conveyance speed (V) of the film was 20 m / min. In order to dry the solvent of the coating solution and to mature the orientation of the discotic liquid crystal compound, the coating liquid was heated with warm air at 100 ° C. for 30 seconds and further with warm air at 130 ° C. for 90 seconds. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form the retardation layer 2 to obtain an optical compensation film.
Composition of coating liquid for forming retardation layer 2:
91 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by mass of the following discotic liquid crystalline compound Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following pyridinium salt 0.5 part by mass The above fluoropolymer (FP2) 0.4 part by mass Methyl ethyl ketone 195 parts by mass

  The direction of the slow axis was orthogonal to the rotation axis of the rubbing roller. That is, the slow axis was parallel to the longitudinal direction of the support. In the same manner as in Example 1, Re (0 °), Re (40 °), and Re (−40 °) were measured using KOBRA21 ADH, and were measured at 139.7 nm, 125.3 nm, and 125.4 nm, respectively. there were. From these results, the average inclination angle of the disc surface of the discotic liquid crystalline molecules with respect to the film surface was 90 °, and it was confirmed that the discotic liquid crystal was aligned perpendicular to the film surface. The wavelength dispersion of the formed retardation layer was 1.16 (Re (450) / Re (550)) and 0.93 (Re (650) / Re (550)).

  In this way, optical compensation films were produced by combining each of the above films and the retardation layer 1 or 2. Further, when each of the retardation layers 1 and 2 was formed, the coating amount of the coating liquid containing the discotic liquid crystal compound was changed and adjusted so as to obtain desired Re and Rth. In addition, in the optical compensation film used in some examples described later, one of the polymer films was laminated on the surface of the retardation layer formed by the above method.

3. Preparation of Polarizing Plate The surface of a support of TD80UL (manufactured by Fuji Film) was subjected to alkali saponification treatment. It was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes, washed in a water bath at room temperature, and neutralized with 0.1 N sulfuric acid at 30 ° C. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. Subsequently, a roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an iodine aqueous solution and dried to obtain a polarizing film having a thickness of 20 μm.
One of the optical compensation films prepared above or one of the polymer films is bonded to the other surface, and the polarizing film is sandwiched between them. TD80UL and the optical compensation film or polymer film serve as a protective film for the polarizing film A polarizing plate was prepared. For pasting, an aqueous polyvinyl alcohol adhesive solution was used. Moreover, when bonding a cellulose acylate film, it bonded, after implementing the saponification process by an alkaline solution. The lamination was performed by laminating the slow axis of the optical compensation film or polymer film to be laminated and the absorption axis of the polarizing film in parallel or orthogonal. In addition, it produced similarly about the polarizing plate which bonded TD80UL only to the surface of the polarizing film, and did not bond any film on the other surface.

4). Production and evaluation of liquid crystal display device (1) Production of IPS type liquid crystal display device The polarizing plates on both sides were peeled off from a liquid crystal TV manufactured by Toshiba (37Z3500) and used as an IPS type liquid crystal cell. Δn · d = 311 nm and the pretilt was 2.0 degrees.

  An IPS type liquid crystal display device of an example and a comparative example having the same configuration as that shown in any of FIGS. Specifically, any of the polarizing plates prepared above was disposed as the polarizing plates POL1 and POL2 in the drawing. used. The characteristics of each member used in each of the examples and comparative examples are summarized in the following table.

(2) Production of FFS type liquid crystal display device The polarizing plates on both sides were peeled off from a liquid crystal TV manufactured by Toshiba (37H3000) and used as an FFS type liquid crystal cell. Δn · d = 360 nm and the pretilt was 2.5 degrees.
In the same manner as described above except that an FFS liquid crystal cell is used instead of the IPS liquid crystal cell, the FFS type of the example and comparative example having the same configuration as that shown in any of FIGS. A liquid crystal display device was produced.

(3) Evaluation of liquid crystal display device / Evaluation of viewing angle contrast The produced liquid crystal display devices are displayed in white and black, and the luminance at the time of white display and black display at a polar angle of 60 ° from the normal direction of the display surface. The ratio (contrast) was measured using a color luminance meter (BM-5 manufactured by Topcon Co., Ltd.), and the average value was obtained by changing the azimuth direction in 0-360 ° and 15 ° increments in the polar angle direction of 60 °. And the viewing angle contrast was calculated. The results are shown in the table below. Practically, the viewing angle contrast is required to be 30 or more.
・ Evaluation of front contrast Each manufactured liquid crystal display device is displayed in white and black, and the luminance ratio (contrast) at the time of white display and black display on the front of the display surface is measured by a color luminance meter (BM manufactured by Topcon Corporation). -5) was used to measure the front contrast. The results are shown in the table below. In practice, the front contrast is required to be 700 or more.
-Evaluation of color shift Each produced liquid crystal display device is displayed in black, and the color in the polar angle direction of 60 ° from the normal direction of the display surface is measured using a color luminance meter (BM-5 manufactured by Topcon Co., Ltd.). The color shift amount ΔE was calculated. The color shift amount ΔE is a color difference in the Luv color system, and is calculated when the azimuth angle direction is changed in increments of 0 to 360 ° and 15 ° in the polar angle direction of 60 ° from the normal direction. Defined as the average color difference. In practice, ΔE is required to be 0.3 or less.

  “A” in the column of the evaluation result in the table below has the highest evaluation result, “B” is inferior to “A”, but there is no practical problem, and “C” means that the evaluation result is low. To do.

  From the results shown in the above table, it can be understood that the IPS or FFS type liquid crystal display device of the example is excellent in both viewing angle contrast and front contrast. On the other hand, in the IPS or FFS type liquid crystal display devices of the reference example and the comparative example, either the Re of the first retardation region or the Re of the second retardation region is outside the scope of the present invention. It can be seen that neither improvement in contrast has been achieved.

  6 to 8, each of the liquid crystal display devices of Examples 1 to 3 (all of which are the liquid crystal display devices having the same configuration as that shown in FIG. 1) is obliquely polarized (polar angle) during black display. The schematic diagram which showed on the Poincare sphere the locus | trajectory of the polarization state of the light which injected from the direction of 60 degrees and an azimuth angle of 135 degrees is shown. Specifically, it is as follows. Light that is incident from an oblique direction during black display passes through the second polarizing film 18 to be in an incident polarization state specified by coordinates on a Poincare sphere indicated by a circle in each figure. Incident light passes through the protective film 24 and the liquid crystal cell 10 during black display while substantially maintaining this polarization state. After that, by passing through the second phase difference region 22 and the first phase difference region 20 each having a predetermined optical characteristic, the polarization state changes in accordance with the locus indicated by the arrow in the figure, and the Poincare sphere indicated by the circle in the figure. The outgoing polarization state specified by the upper coordinates is obtained. Since this outgoing polarization state is a polarization state absorbed by the absorption axis of the first polarizing film 16, the liquid crystal display devices of Examples 1 to 3 have excellent fields of view with no light leakage in an oblique direction during black display. Shows angular characteristics. In other embodiments, the optical compensation can be similarly explained by the locus of the polarization state on the Poincare sphere.

The first and second retardation regions used in each of the above examples satisfied both the following relational expressions (a) and (b).
(A) −2 × Re1 + 220 ≦ Re2 ≦ −2 × Re1 + 380
(B) −1.5 × Rth1−80 ≦ Rth2 ≦ −1.5 × Rth1 + 30

5. Example using thin polymer film A dope P10 and a dope T30 each having the following compositions were prepared.
Composition of dope P10:
Commercially available Mitsubishi Rayon Co., Ltd. Dianal BR88 100.0 parts by mass Additive AA1 5.8 parts by mass Additive AA2 1.8 parts by mass Additive UU1 2.0 parts by mass Composition of Dope T30:
Cellulose acylate (substitution degree 2.42) 100.0 parts by mass Additive AA1 5.8 parts by mass Additive AA2 1.8 parts by mass Additive UU1 2.0 parts by mass

  Additive AA1 is a compound represented by the following formula. In the following structural formula, R represents a benzoyl group, and an average substitution degree of 5 to 7 was used.

Additive AA2 is a compound represented by the following formula. Each structural formula and substitution degree of R ⁹ are shown below.

  The additive UU1 is a compound represented by the following formula.

A laminated film was produced by a solution casting method using the dope P10 and the dope T30. Specifically, the above-mentioned two kinds of dopes were cast on a metal support through a casting giuser capable of co-casting with three layers. At this time, the lower layer (T30), the intermediate layer (P10), and the upper layer (T30) were cast in this order from the metal support surface side. The viscosity of each layer was appropriately adjusted according to the solid content concentration according to the combination of each dope so that co-casting was possible, and set so that uniform casting was possible. While on the metal support, the dope was dried with a drying air at 40 ° C. to form a film, and then peeled off. Both ends of the film were fixed with pins, and 5 ° Dried for minutes. After removing the pin, the film was further dried at 130 ° C. for 20 minutes and wound up in the state of a laminated film.
Thereafter, the three-layer laminated film was peeled off. The film thickness of the lower layer film was 20 μm. In this way, a thin polymer film could be stably produced.

  This thin film was placed in place of TD80UL used for the production of the polarizing plate, and liquid crystal display devices having the same configuration were manufactured. When these liquid crystal display devices were evaluated in the same manner as described above, good evaluation results were obtained in the same manner as in each of the examples.

6). Example Using Thin Film Polarizing Film According to the method described in Japanese Patent No. 4804588, a thin film polarizing film was produced as follows. Isophthalic acid copolymerized polyethylene terephthalate copolymerized with 6 mol% of isophthalic acid was prepared as an amorphous ester-based thermoplastic resin substrate. On this resin base material, a PVA resin layer was formed by coating. The resin base material and the PVA resin layer are integrally stretched in a two-stage stretching process consisting of air-assisted stretching and boric acid water stretching, and the PVA resin layer is dyed with a dichroic dye. A polarizing film having a thickness of 3 μm was prepared. When this polarizing film was used and evaluated in the same manner as described above, good evaluation results were obtained as in the examples.

DESCRIPTION OF SYMBOLS 10 Liquid crystal layer 12, 14 Substrate 16 1st polarizing film 18 2nd polarizing film 20 1st phase difference area | region 22 2nd phase difference area | region 24 Protective film 26 Backlight

Claims (20)

A first polarizing film;
An optical compensation film comprising a first retardation region and a second retardation region in contact with the first retardation region;
A first substrate;
A liquid crystal layer made of a nematic liquid crystal material;
A second substrate;
In this order, and the liquid crystal display device in which the liquid crystal molecules of the nematic liquid crystal material are aligned in parallel to the surfaces of the pair of substrates during black display,
The first retardation region and the slow axis of the second retardation region are parallel to each other;
The first retardation region includes a retardation layer containing a vertically aligned discotic liquid crystal compound, and the in-plane retardation Re (550) of the wavelength of 550 nm of the first retardation region satisfies 100 nm or less, and IPS or FFS type liquid crystal display device satisfying an in-plane retardation Re (550) of 20 nm or more in a two phase difference region with a wavelength of 550 nm:
However, the in-plane retardation Re is defined as Re = (nx−ny) × d using the in-plane refractive indexes nx and ny (nx ≧ ny) and the film thickness d. The in-plane retardations Re1 and Re2 of each of the first retardation region and the second retardation region satisfy the following relational expression (a), and the letters in the thickness direction of the first retardation region and the second retardation region respectively. The IPS or FFS type liquid crystal display device according to claim 1, wherein the foundations Rth1 and Rth2 satisfy the following relational expression (b):
(A) −2 × Re1 + 220 ≦ Re2 ≦ −2 × Re1 + 380
(B) −1.5 × Rth1−80 ≦ Rth2 ≦ −1.5 × Rth1 + 30
However, Re1 and Re2 respectively represent Re (550) of the first phase difference region and the second phase difference region, and Rth1 and Rth2 respectively represent thickness directions at a wavelength of 550 nm of the first phase difference region and the second phase difference region. Retardation Rth (550). 3. The IPS or FFS type liquid crystal display device according to claim 1, wherein an absolute value | Rth (550) | of Rth (550) of the entire optical compensation film is 30 nm or less.
However, Rth (550) means the retardation Rth in the thickness direction at a wavelength of 550 nm, and the retardation in the thickness direction has an in-plane refractive index nx and ny (nx ≧ ny), a thickness direction refractive index nz, And Rth = {(nx + ny) / 2−nz} × d using the film thickness d. Re, Re (450), Re (550), and Re (650) at wavelengths of 450 nm, 550 nm, and 650 nm of the first retardation region have Re (450) / Re (550) of 1 or more and 1.13 or less, The IPS or FFS type liquid crystal display device according to claim 1, wherein Re (650) / Re (550) satisfies 0.94 or more and 1 or less. The IPS or FFS type liquid crystal display device according to any one of claims 1 to 4, wherein the IPS or FFS type liquid crystal display device is disposed in the order of a first polarizing film, a first retardation region, and a second retardation region. The IPS or FFS type liquid crystal display device according to any one of claims 1 to 4, wherein the IPS or FFS type liquid crystal display device is disposed in the order of a first polarizing film, a second retardation region, and a first retardation region. The second retardation region includes a plurality of layers, a layer in contact with the first retardation region among the plurality of layers is an alignment film, and the first retardation region is a discotic liquid crystal compound and an alignment control agent. The IPS according to any one of claims 1 to 6, wherein the alignment control agent has an action of reducing a tilt angle of a director of a discotic liquid crystal compound on the air interface side. FFS type liquid crystal display device. The IPS or FFS type liquid crystal display device according to claim 1, wherein the second retardation region is made of a polymer film. The IPS or FFS type liquid crystal display device according to claim 8, wherein the polymer film includes a cellulose acylate film, a cyclic olefin polymer film, or an acrylic polymer film. The IPS or FFS type liquid crystal display device according to claim 8 or 9, wherein the polymer film is made of a composition containing, as a main component, cellulose acylate having an acyl group containing an aromatic group. The IPS or FFS type liquid crystal display device according to claim 5, wherein the first retardation region has a polymer film together with the retardation layer, and the polymer film is in contact with the first polarizing film. The IPS according to any one of claims 1 to 11, further comprising a second polarizing film outside the second substrate, and a polymer film between the second polarizing film and the second substrate. FFS type liquid crystal display device. The polymer film has an in-plane retardation Re (550) having an absolute value | Re (550) | of 10 nm or less, and an absolute value of the retardation Rth (550) in the thickness direction of the same wavelength | Rth ( 550) | is a film having a thickness of 30 nm or less. The IPS or FFS type liquid crystal display device according to claim 11 or 12. 14. The polymer film according to claim 11, wherein | Re (400) −Re (700) | is 10 nm or less and | Rth (400) −Rth (700) | is 35 nm or less. The IPS or FFS type liquid crystal display device described. The IPS or FFS type liquid crystal display device according to any one of claims 11 to 14, wherein the polymer film has a thickness of 10 to 90 µm. The IPS or FFS type liquid crystal display device according to any one of claims 11 to 15, wherein the polymer film includes a cellulose acylate film, a cyclic olefin polymer film, or an acrylic polymer film. The acrylic polymer film according to claim 16, wherein the acrylic polymer film is an acrylic polymer film containing an acrylic polymer containing at least one unit selected from a lactone ring unit, a maleic anhydride unit, and a glutaric anhydride unit. IPS or FFS type liquid crystal display device. The IPS or FFS type liquid crystal display device according to claim 1, further comprising a protective film on the other surface of the first polarizing film or the second polarizing film. The IPS or FFS type liquid crystal display device according to claim 18, wherein the protective film has a thickness of 10 to 90 μm. 19. The IPS or FFS type liquid crystal display device according to claim 1, wherein a thickness of the first polarizing film or the second polarizing film is 50 μm or less.

Images