JP2018036657A - Retardation film, polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retardation film capable of enhancing front contrast of a liquid crystal display device, and a polarizing plate and a liquid crystal display device using the retardation film.SOLUTION: The retardation film includes a first optical anisotropic layer and a second optical anisotropic layer on the surface of the first optical anisotropic layer, in which the first optical anisotropic layer is formed by fixing a liquid crystal compound in a homogeneous alignment state and has an order parameter of 0.75 to 0.95 and a layer thickness of 0.3 to 3.0 μm, while the second optical anisotropic layer is formed by fixing a liquid crystal compound in a homeotropic alignment state and has an order parameter of 0.60 to 0.95 and a layer thickness of 0.3 to 3.0 μm. An order parameter OP is defined by OP=(A-A⊥)/(2A⊥+A), where Arepresents an absorbance of a liquid crystal compound with respect to light polarized parallel to an alignment direction; and A⊥ represents an absorbance of the liquid crystal compound with respect to light polarized perpendicular to the alignment direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a retardation film. The present invention also relates to a polarizing plate and a liquid crystal display device using a retardation film.

  In recent years, tablets and mobiles using liquid crystal display devices in IPS (In-Place-Switching) mode have been widely used. As an optical film used for tablets and mobiles, for example, the use of an optically anisotropic layer utilizing the orientation of a liquid crystal compound has been studied. Specifically, a retardation film in which an optically anisotropic layer is provided on one surface of a transparent substrate and a retardation layer is provided on the other surface is described (FIG. 1 in Patent Document 1).

  In addition, with the demand for thinning of tablets and mobiles, there is an increasing demand for thinning retardation films used in IPS mode liquid crystal display devices. Patent Document 2 is known as a technique for thinning a retardation film. Specifically, Patent Document 2 discloses a retardation film in which a positive C plate and a positive A plate or an optical biaxial plate are directly adhered and laminated without using an adhesive. .

JP 2009-86260 A JP 2012-255926 A

Here, Patent Document 1 does not specifically describe a method of forming a retardation layer on the surface of an optically anisotropic layer. From the viewpoint of thinning, it is required that a retardation layer can be appropriately formed on the surface of the optically anisotropic layer. Furthermore, when Example 1 specifically described in Patent Document 1 was further tested by the inventor, it was found that sufficient front contrast was not always obtained.
In addition, with respect to Patent Document 2, when the present inventor reexamined Example 1, it was confirmed that the compensation of the polarizing plate (light leakage at the viewing angle) tends to be reduced with respect to the form without the retardation film. However, it has been found that the front contrast is significantly inferior to a retardation film having a thickness of about 100 μm that is currently on the market.
An object of the present invention is to provide a retardation film capable of increasing the front contrast of a liquid crystal display device. Another object of the present invention is to provide a polarizing plate and a liquid crystal display device using such a retardation film.

  As a result of intensive studies by the present inventors based on the above problems, in the retardation film having at least two optically anisotropic layers adjacent to each other, the orientation before each optically anisotropic layer is fixed It has been found that the above problems can be solved by setting the state, order parameter and film thickness within a predetermined range. Specifically, the above problem has been solved by the following means <1>, preferably <2> to <17>.

<1> A first optically anisotropic layer and a second optically anisotropic layer on the surface of the first optically anisotropic layer,
The first optically anisotropic layer is formed by fixing a liquid crystal compound in a homogeneous alignment state, the order parameter is 0.75 to 0.95, and the thickness of the layer is 0.3 to 3.0 μm. Yes,
The second optically anisotropic layer is formed by fixing the liquid crystal compound in a homeotropic alignment state, the order parameter is 0.60 to 0.95, and the thickness of the layer is 0.3 to 3.0 μm. A retardation film; provided that the order parameter OP is
OP = (A _|| -A⊥) / (2A⊥ + A _|| )
“A _|| ” means absorbance for light polarized parallel to the alignment direction of the liquid crystal compound “A⊥” means absorbance for light polarized perpendicular to the alignment direction of the liquid crystal compound.
<2> The retardation film according to <1>, wherein the first optically anisotropic layer is a layer formed by fixing a liquid crystal compound in a smectic phase state.
<3> The retardation film according to <1> or <2>, wherein the second optically anisotropic layer is a layer formed by fixing a liquid crystal compound in a nematic phase.
<4> The retardation film according to any one of <1> to <3>, wherein the first optically anisotropic layer satisfies the following formulas (1) and (2):
Formula (1)
100 nm ≦ Re (550) ≦ 200 nm
Formula (2)
0.8 ≦ Nz ≦ 1.2
In the formula (1), Re (550) indicates in-plane retardation at a wavelength of 550 nm.
In Formula (2), Nz represents (nx−nz) / (nx−ny), nx represents the refractive index in the slow axis direction in the plane, and ny represents the refraction in the direction perpendicular to nx in the plane. Nz represents the refractive index in the direction orthogonal to nx and ny.
<5> The retardation film according to any one of <1> to <4>, wherein the first optically anisotropic layer satisfies the following formula (3);
Formula (3)
Re (450) / Re (650) <1
In formula (3), Re (450) and Re (650) indicate in-plane retardation at wavelengths of 450 nm and 650 nm, respectively.
<6> The retardation film according to any one of <1> to <5>, wherein the first optically anisotropic layer contains a leveling agent.
<7> The retardation film according to any one of <1> to <6>, wherein the second optically anisotropic layer contains a vertical alignment agent.
<8> The retardation film according to any one of <1> to <7>, wherein the retardation film has a thickness of 0.6 to 6 μm.
<9> The retardation film according to any one of <1> to <8>, wherein each of the first optical anisotropic layer and the second optical anisotropic layer contains a rod-like liquid crystal compound.
<10> The retardation film according to any one of <1> to <9>, which has an alignment film, a first optical anisotropic layer, and a second optical anisotropic layer in this order on a support.
A polarizing plate having a <11> polarizing film and a retardation film according to any one of <1> to <10>.
<12> The polarizing plate according to <11>, wherein a first optical anisotropic layer is provided on a surface of the polarizing film.
<13> A liquid crystal display device having the retardation film according to any one of <1> to <10> or the polarizing plate according to <11> or <12>.
<14> The liquid crystal display device according to <13>, which is for IPS mode.
<15> The liquid crystal display device according to <13> or <14>, having the polarizing plate according to <11> or <12> on the front side of the liquid crystal display device.
<16> In-plane retardation Re (550) at a wavelength of 550 nm is 30 to 120 nm between the polarizing film on the rear side of the liquid crystal display device and the liquid crystal cell, and retardation Rth (550) in the thickness direction at a wavelength of 550 nm. The liquid crystal display device according to <15>, having an optical film having a thickness of 20 to 100 nm.
<17> The liquid crystal display device according to <16>, wherein the optical film on the rear side of the liquid crystal display device has an optically anisotropic layer in which a liquid crystal compound is inclined and aligned.

  According to the present invention, it is possible to provide a retardation film capable of increasing the front contrast of a liquid crystal display device. In addition, a polarizing plate and a liquid crystal display device using such a retardation film can be provided.

It is the schematic which shows an example of a structure of the phase difference film of this invention. It is the schematic which shows another example of a structure of the phase difference film of this invention. It is the schematic which shows another example of a structure of the phase difference film of this invention. It is the schematic which shows an example of a structure of the liquid crystal display device of this invention. It is the graph which showed an example of the relationship between an order parameter, NI point, and hardening temperature.

Hereinafter, the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. In the present specification, numerical ranges and numerical values should be construed as numerical ranges and numerical values including errors allowed in the technical field to which the present invention belongs.
In the present specification, the relationship between the optical axes includes an error allowed in the technical field to which the present invention belongs. In the present specification, “parallel”, “orthogonal” and “vertical” mean that the angle is within a range of a strict angle ± 5 ° or less. The error from the exact angle is preferably within a range of less than ± 4 °, and more preferably within a range of less than ± 3 °.

  The retardation film of the present invention has a first optical anisotropic layer and a second optical anisotropic layer on the surface of the first optical anisotropic layer, and the first optical anisotropy. The layer is formed by fixing the liquid crystal compound in a homogeneous alignment state, the order parameter is 0.75 to 0.95, the layer thickness is 0.3 to 3.0 μm, and the second optical The anisotropic layer is characterized in that the liquid crystal compound is fixed in a homeotropic alignment state, and the order parameter is 0.60 to 0.95. By setting it as such a structure, the thickness of a phase difference film can be made thin and a high front contrast can be achieved when it incorporates in a liquid crystal display device. The configuration having the second optical anisotropic layer on the surface of the first optical anisotropic layer is also described in Patent Document 2 described above. However, as a result of studies by the inventor, it has been found that the front contrast is not necessarily sufficient in the retardation film described in Example 1 of Patent Document 2. When this reason was further examined, it was found that the orientation of the positive C plate was disturbed. That is, the liquid crystal compound is known to be easily affected by the lower base material, and the liquid crystal compound is directly contained on the surface of the positive A plate using a known technique as in Patent Document 2. The layer directly coated with the coating solution is affected by the positive A plate, which is the lower substrate. As a result, the orientation of the liquid crystal compound is disturbed at the interface portion between the positive A plate and the layer directly coated with the coating liquid containing the liquid crystal compound, and an optical anisotropic layer (positive C plate) provided on the surface of the positive A plate. ) Cannot achieve the predetermined order parameters. Furthermore, the liquid crystal compound specifically described in Patent Document 2 is presumed that since the positive A plate exhibits nematic properties, the original order parameter is low (around 0.7) and the front contrast is further reduced. be able to.

  In the present invention, not only the first optically anisotropic layer but also the second optically anisotropic layer on the surface of the first optically anisotropic layer is aligned with a liquid crystal compound with a high alignment order. The problem is solved. That is, a liquid crystal display is formed by forming a second optically anisotropic layer in which a liquid crystal compound is homeotropically aligned and fixed on the surface of the first optically anisotropic layer in which the liquid crystal compound is orderly and homogeneously aligned. High front contrast is achieved when installed in the device. Furthermore, by adopting the configuration of the present invention, the color and vertical symmetry of the display of the liquid crystal display device can be improved.

  Here, in the present invention, the degree of alignment order of the liquid crystal compound forming the first and second optically anisotropic layers is defined by the order parameter. Here, the order parameter will be described. In order to generate optical anisotropy, the orientation of the optical element is necessary. The optical element referred to here is an optical element that causes anisotropy of the refractive index, and is aligned by, for example, a disk-like or rod-like liquid crystal molecule that exhibits a liquid crystal phase in a predetermined temperature range, and a stretching process. Examples include polymers. The intrinsic birefringence of an optical element and the statistical orientation of the optical element determines the bulk birefringence of the optical material. For example, the magnitude of optical anisotropy of an optically anisotropic layer composed of a liquid crystal compound depends on the intrinsic birefringence of the liquid crystal compound, which is the main optical element causing optical anisotropy, and the statistics of the liquid crystal compound. Determined by the degree of general orientation. An order parameter S is known as a parameter representing the degree of orientation. The orientation order parameter is 1 when there is no distribution as in a crystal, and 0 when it is completely random as in a liquid state. For example, it is said that a nematic liquid crystal usually takes a value of about 0.6. Regarding the order parameter S, for example, DE JEU, W.M. H. (Author) “Physical properties of liquid crystals” (Kyoritsu Shuppan, 1991, p. 11) is described in detail, and is expressed by the following formula.

θ is an angle formed by the average orientation axis direction of the orientation elements and the axis of each orientation element.

As means for measuring the order parameter, a polarization Raman method, an IR method, an X-ray method, a fluorescence method, a sound velocity method, and the like are known.
The order parameter can be obtained relatively easily from the following equation when the optically anisotropic layer has dichroism.
OP = (A _|| -A⊥) / (2A⊥ + A _|| )
“A _|| ” means absorbance for light polarized parallel to the alignment direction of the liquid crystal compound “A⊥” means absorbance for light polarized perpendicular to the alignment direction of the liquid crystal compound.
The fact that the order parameter is one of the indices indicating the degree of orientation of the liquid crystal compound is that “Liquid Crystal Polymer Development Technology—High Performance and High Functionality” (CMC Publishing), page 5 and Japanese Patent Application Laid-Open No. 2008-297210. It is publicly known as described in the publication.
As the value of the order parameter is closer to 1, the liquid crystal compounds are regularly arranged. That is, the closer the order parameter is to 1, the closer to the crystallinity. In practice, the maximum value of the order parameter indicating liquid crystallinity is about 0.95. Therefore, the upper limit value of the order parameter of the first and second optical anisotropic layers in the present invention is set to 0.95.
The absorbance can be obtained by “absorbance = 1−transmittance”.
In addition, a specific method for measuring the order parameter in the present invention is as follows.
A liquid crystal compound to which a dichroic dye is added is aligned on a rubbing alignment film, and the film is hardened through a drying and ultraviolet curing process. For this liquid crystal film, the polarization direction of the incident light of the spectrophotometer is fixed vertically, and the spectrum (absorbance) when the liquid crystal thin film is oriented vertically and horizontally is measured separately. The measured polarization absorption spectrum (absorbance) of quartz glass is subtracted to be A⊥ and A ||. This is calculated from the above order parameter equation.

It was also found that this order parameter strongly correlates with the degree of depolarization in the front direction and the oblique direction when a retardation film is disposed between two polarizing plates arranged in crossed Nicols.
The degree of depolarization is closely related to the contrast when mounted on a liquid crystal display, and it is desired in the market to suppress this degree of depolarization. In addition to the scattering performance of the film, the degree of depolarization varies depending on the slow axis and polarization axis of the film. When the order parameter of the liquid crystal is lowered, the liquid crystal molecules generate minute alignment fluctuations, and thus light scattering may reduce the degree of depolarization. Here, the degree of depolarization is preferably 0.000080 or less, more preferably 0.000025 or less, further preferably 0.000024 or less, and further preferably 0.000022 or less. By setting it as such a depolarization degree, the effect of this invention is exhibited more effectively.
Depolarization degree D is D = Lmin / Lmax−L ₀ min / L ₀ max
Lmin is the maximum luminance L ₀ min cross Nicol minimum luminance Lmax is disposed between two polarizing plates parallel Nicols retardation film between two polarizing plates in the arrangement phase difference film of crossed nicols The minimum luminance L ₀ max of the two polarizing plates means the maximum luminance of the two polarizing plates in the parallel Nicol state.
When the present inventors investigated the cause of the front contrast change of the film using a high order parameter liquid crystal compound, it turned out that the depolarization degree of retardation film is related. That is, it was found that the front contrast is improved by reducing the degree of depolarization. As a result of further detailed investigation, it was found that the orientation order (order parameter) tends to decrease due to the alignment fluctuation of the liquid crystal of the retardation film, and light scattering tends to occur. It has been found that the degree of depolarization is improved by improving the order parameter, and the front contrast when the retardation film of the present invention is incorporated in a liquid crystal display device is remarkably improved.

As a method for improving the degree of depolarization in the oblique direction of the retardation film of the present invention, for example, when forming an optically anisotropic layer, a specific liquid crystal compound is selected as described above, and two or more liquid crystal compounds are selected. In a predetermined mixing ratio, a predetermined additive, a temperature of ultraviolet irradiation for orientation curing, an optimization of temperature for orientation drying, and the like. As a result, a reduction in contrast (CR) due to light scattering of the liquid crystal due to alignment fluctuation can be reduced.
Further, as a result of investigation by the inventor, as shown in FIG. 5 as an example in the case of the C-plate, the order parameter tends to become higher as the NI point (Nematic-Isotropic transition temperature) of the liquid crystal compound is higher. I found it.
Moreover, when the correlation with the temperature which carries out orientation hardening using the liquid crystal compound with the same NI point is calculated | required similarly, it has also found out that the order parameter tends to become high, so that the temperature which carries out orientation hardening is low.

In general, the haze of a retardation film may be considered as a physical property that affects the front contrast of a liquid crystal display device. The haze is represented by the ratio of the total transmitted light of the retardation film to the total amount of light with the diffused light source. As a result of investigations by the present inventors, as shown in Table 1 below, haze cannot sufficiently detect the difference in front contrast, and in an actual liquid crystal display device, the light passes through a polarizing plate from a diffusion light source and is polarized. Since light is incident on the retardation film, the measurement result may differ from the actual measurement system. Since the degree of depolarization of the present invention is a measurement system in which actual polarized light is incident, it correlates with the front contrast of the liquid crystal display device, and the improvement of the measurement system greatly contributes to the present invention.
Below, an example of the measurement result of the depolarization degree of the sample which changed NI point and ultraviolet curing temperature of a liquid crystal compound variously is shown.

Details of the first and second optically anisotropic layers will be described below.

<First optically anisotropic layer>
The first optically anisotropic layer in the present invention comprises a liquid crystal compound fixed in a homogeneous alignment state, an order parameter of 0.75 to 0.95, and a layer thickness of 0.3 to 3 0.0 μm. The order parameter in the first optically anisotropic layer is preferably from 0.80 to 0.90, more preferably from 0.84 to 0.90, from the viewpoint of production suitability. The layer satisfying such order parameters is preferably a layer formed by fixing a liquid crystal compound in a smectic phase. Details of the manufacturing method of the first optically anisotropic layer will be described later.

  The first optically anisotropic layer used in the present invention has a layer thickness of 0.3 to 3.0 μm. When the thickness of the first optically anisotropic layer is less than 0.3 μm or thicker than 3.0 μm, it is incorporated into the liquid crystal display device from the viewpoint of controlling the retardation of the formed first optically anisotropic layer. The front contrast is poor. The film thickness of the first optically anisotropic layer in the present invention is preferably 0.5 μm or more, more preferably 0.7 μm or more, further preferably 0.9 μm or more, and preferably 2.8 μm or less. 5 μm or less is more preferable, 2.0 μm or less is more preferable, 1.5 μm or less is more preferable, and 1.3 μm or less is particularly preferable.

The retardation of the first optically anisotropic layer used in the present invention preferably satisfies 80 nm ≦ Re (550) ≦ 230 nm, more preferably satisfies 90 nm ≦ Re (550) ≦ 220 nm, and 100 nm. More preferably, ≦ Re (550) ≦ 200 nm is satisfied, and 105 nm ≦ Re (550) ≦ 130 nm is particularly preferable. Here, Re (550) indicates in-plane retardation at a wavelength of 550 nm.
The first optically anisotropic layer preferably satisfies 90 nm ≦ Rth (550) ≦ 150 nm, and more preferably satisfies 95 nm ≦ Rth (550) ≦ 130 nm. Here, Rth (550) indicates retardation in the thickness direction at a wavelength of 550 nm.
Furthermore, it is preferable that the 1st optically anisotropic layer in this invention satisfy | fills following formula (2).
Formula (2)
0.8 ≦ Nz ≦ 1.2
In Formula (2), Nz represents (nx−nz) / (nx−ny), nx represents the refractive index in the slow axis direction in the plane, and ny represents the refraction in the direction perpendicular to nx in the plane. Nz represents the refractive index in the direction orthogonal to nx and ny.
More preferably, Nz satisfies 0.9 ≦ Nz ≦ 1.1.
The first optically anisotropic layer preferably satisfies 100 nm ≦ Re (550) ≦ 200 nm and the formula (2).
By setting it as such a range, the effect of this invention is more effectively exhibited when it incorporates in the liquid crystal display device for IPS modes.

Furthermore, the first optically anisotropic layer preferably exhibits reverse wavelength dispersion, and more preferably satisfies the following formula (3). By setting it as such a structure, the color tone when the retardation film of this invention is integrated in a liquid crystal display device can be improved more.
Formula (3)
Re (450) / Re (650) <1
(In formula (3), Re (450) and Re (650) represent in-plane retardation at a wavelength of 450 nm or 650 nm, respectively.)

<Second optically anisotropic layer>
In the second optically anisotropic layer in the present invention, the liquid crystal compound is fixed in a homeotropic alignment state, the order parameter is 0.60 to 0.95, and the thickness of the layer is 0.3 to It is characterized by being 3.0 μm. When the thickness of the second optically anisotropic layer is less than 0.3 μm or thicker than 3.0 μm, the front contrast when incorporated in a liquid crystal display device is inferior. The order parameter in the second optically anisotropic layer is preferably 0.65 to 0.80, and more preferably 0.65 to 0.75. The layer satisfying such order parameter is preferably a layer fixed in a smectic phase or a nematic phase, and since the orientation direction is parallel to the light transmission direction, it is oriented in terms of manufacturability. It is more preferable to select a layer that is fixed in a nematic phase with a high degree of order. In the present invention, since the second optical anisotropic layer, which is a layer fixed in the state of a smectic phase or a nematic phase having a high orientation order, can be formed directly on the surface of the first optical anisotropic layer, a thin film High front contrast can be achieved.
Means for directly forming such a second optically anisotropic layer on the surface of the first optically anisotropic layer will be described later.

  The second optically anisotropic layer used in the present invention has a layer thickness of 0.3 to 3.0 μm. In the present invention, even such a thin film can exhibit desired optical characteristics, which is advantageous from the viewpoint of thinning. The film thickness of the second optically anisotropic layer in the present invention is preferably 0.5 μm or more, more preferably 0.7 μm or more, further preferably 0.9 μm or more, and preferably 2.8 μm or less. 5 μm or less is more preferable, 2.0 μm or less is more preferable, 1.5 μm or less is further preferable, and 1.2 μm or less is particularly preferable.

The second optically anisotropic layer used in the present invention preferably satisfies Re (550) ≦ 5 nm, and more preferably satisfies Re (550) ≦ 3 nm. Here, Re (550) indicates in-plane retardation at a wavelength of 550 nm.
The second optically anisotropic layer preferably satisfies −300 nm ≦ Rth (550) ≦ 0 nm, more preferably satisfies −200 nm ≦ Rth (550) ≦ −60 nm, and −150 nm ≦ Rth (550). ) ≦ -80 nm is more preferable. By setting it as such a range, the effect of this invention is more effectively exhibited when it incorporates in the liquid crystal display device for IPS modes.

<Method for producing retardation film>
The retardation film of the present invention is usually formed by applying (preferably coating) the composition for forming the second optical anisotropic layer to the surface of the first optical anisotropic layer, and curing it. The
Here, the first optical anisotropic layer can be formed by a known means using an alignment film. However, when the second optical anisotropic layer is formed by laminating the first optical anisotropic layer. In some cases, the orientation of the liquid crystal compound at the interface is disturbed by the influence of the surface of the first optically anisotropic layer as the lower layer. In particular, when the second optically anisotropic layer is directly laminated on the first optically anisotropic layer, the influence is remarkable. In the present invention, for example, this point can be solved by adopting one or more of the following means in combination.

As a first means, a leveling agent may be added to the first optically anisotropic layer.
By blending the leveling agent, the surface of the first optical anisotropic layer becomes smooth, and the liquid crystal compound can be aligned with high alignment order in the second optical anisotropic layer. When the leveling agent is added, the leveling agent is quickly unevenly distributed on the surface of the applied composition, and the leveling agent is unevenly distributed on the surface as it is after the first optical anisotropic layer is dried. The surface energy of the optically anisotropic layer is lowered by the leveling agent. Here, the surface energy (γs ^v : unit, mJ / m ² ) is an experiment on the first optical anisotropic layer with reference to DKOwens: J.Appl.Polym.Sci., 13, 1941 (1969). to obtained pure water between H ₂ O and the respective contact angle theta _{H2 O} in methylene iodide CH ₂ I _2, the following simultaneous equations from theta _CH2I2 (1), the sum of gamma] s ^d and gamma] s ^h determined from (2) This is the energy converted value of the surface tension of the first optically anisotropic layer defined by the represented value γs ^v (= γs ^d + γs ^h ) (mN / m unit is mJ / m ² unit). The sample needs to be conditioned for a certain period of time under a predetermined temperature and humidity condition before measurement. The temperature at this time is preferably in the range of 20 ° C. to 27 ° C., the humidity is preferably in the range of 50 RH% to 65 RH%, and the humidity conditioning time is preferably 2 hours or more.
_{(1) 1 + cosθH 2 O} = 2√γs d (√γ H2O d / γ H2O h v) + 2√γs h (√γ H2O h / γ H2O v)
_{(2) 1 + cosθCH 2 I} 2 = 2√γs d (√γ CH2I2 d / γ CH2I2 v) + 2√γs h (√γ CH2I2 h / γ CH2I2 v)
Here, γ _H2O ^d = 21.8 °, γ _H2O ^h = 51.0 °, γ _H2O ^v = 72.8 °, γ _CH2I2 ^d = 49.5 °, γ _CH2I2 ^h = 1.3 °, and γ _CH2I2 ^v = 50.8 °.
Surface energy of the first optically anisotropic layer is in the range of 45 mJ / m ² or less, preferably in the range of 20~45mJ / m ^2, more preferably in the range of 25~40mJ / m ^2. By setting it as such a range, in a 2nd optically anisotropic layer, a liquid crystal compound can be aligned with higher alignment order.

The leveling agent used in the present invention is preferably a fluorine leveling agent and a silicon leveling agent, more preferably a fluorine leveling agent, particularly including a benzene ring or a triazine ring, and the benzene ring or triazine ring being a perfluoroalkyl group. Compounds having at least two substituents containing are preferred. The substituent containing a perfluoroalkyl group is a group comprising a combination of C _n F _{2n + 1} -L—O— (L is a combination of —CH ₂ — and —CO—. N represents an integer of 1 to 5. .) Is preferred. The molecular weight of the leveling agent is preferably 3000 or less, and more preferably 2000 or less.
Specific examples of the leveling agent include compounds represented by the general formula (I) described in paragraph Nos. 0079 to 0102 of JP2007-069471 and JP2013-047204 (particularly paragraph No. 0020). To 0032), compounds represented by general formula (I) described in JP2012-211306A (in particular, compounds described in paragraphs 0022 to 0029), JP2002-129162A Liquid crystal alignment accelerators represented by the general formula (I) described above (particularly, compounds described in paragraphs 0076 to 0078 and 0082 to 00990), general formula (I) described in JP-A-2005-099248, ( Preferred examples of the compound represented by II) or (III) (particularly the compounds described in paragraphs 0092 to 0096) and the following compounds: It is shown.

  0.01-5 mass% is preferable with respect to the liquid crystal compound contained in a 1st optically anisotropic layer, and a leveling agent has more preferable 0.1-3 mass%. The leveling agent may contain only one type, or may contain two or more types. When two or more types are included, the total amount is within the above range.

As a second means, a vertical alignment agent is added to the second optically anisotropic layer. By blending the vertical alignment agent, the liquid crystal compound can be aligned more effectively at the interface of the second optically anisotropic layer. The vertical alignment agent is preferably a boronic acid compound and / or an onium salt.
As a specific example of the boronic acid compound, a compound represented by the following formula is preferable.
(In the formula, R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group. R ³ is bonded to a (meth) acryl group. Represents a substituent containing a functional group capable of
As specific examples of the boronic acid compounds, the boronic acid compounds represented by the general formula (I) described in paragraph Nos. 0023 to 0032 of JP-A-2008-225281 can be used, and onium salts described therein Can be preferably used. Further, boronic acid compounds shown below are also preferably used.

As a specific example of the onium salt, a compound represented by the following formula is preferable.
(In the formula, ring A represents a quaternary ammonium ion composed of a nitrogen-containing heterocyclic ring, X represents an anion; L ¹ represents a divalent linking group; L ² represents a single bond or a divalent linking group. Y ¹ represents a divalent linking group having a 5- or 6-membered ring as a partial structure; Z represents a divalent linking group having 2 to 20 alkylene groups as a partial structure; P ¹ and P ² are Each independently represents a monovalent substituent having a polymerizable ethylenically unsaturated group.)
Specific examples of the onium salt include onium salts described in paragraph numbers 0052 to 0058 of JP2012-208397A, onium salts described in paragraph numbers 0024 to 0055 of JP2008-026730A, and JP The onium salts described in JP-A-2002-37777 can be used, and the onium salts described therein can be preferably used.

  0.1-5 mass% is preferable with respect to the liquid crystal compound contained in a 2nd optically anisotropic layer, and, as for a vertical aligning agent, 0.5-3 mass% is more preferable. The vertical alignment agent may contain only one type or two or more types. When two or more types are included, the total amount is within the above range.

As a third means, a compound having a hydroxyl group in the lateral direction may be used for the first optical anisotropic layer. When a compound having a hydroxyl group in the lateral direction is included, the compound having a hydroxyl group in the lateral direction is oriented so that the hydroxyl group is regularly arranged at the interface, and the regularly arranged hydroxyl group is the first optical anisotropic layer. It is assumed that the alignment control of the liquid crystal compound in the second optically anisotropic layer provided on the surface of the substrate is strengthened. Here, the lateral direction refers to a direction of approximately 90 ° with respect to the long axis of the molecule, for example, the longest chain.
The orientation control agent of the present invention may contain a low molecular compound having a hydrogen bonding group in the lower layer.
In particular, it is preferable to use a low molecule having a hydrogen bonding group in the lateral direction of the mesogen.
Specifically, the structure described in Journal of Materials Chemistry 1998, Vol. 8, page 1502, may be used.
Specific compound examples are shown below, but are not limited thereto.

<< Method for Producing First Optical Anisotropic Layer >>
Next, the detail of the manufacturing method of the 1st optically anisotropic layer in this invention is described. The first optically anisotropic layer can be produced by forming an alignment film on a support, applying the first composition for forming an optically anisotropic layer on the surface of the alignment film, and curing it. Moreover, it can also manufacture by carrying out the rubbing process of the surface of a polarizing film (for example, polyvinyl alcohol film), applying the 1st composition for optically anisotropic layer formation to the surface, and making it harden | cure.

  In the present invention, it is preferable to use modified or unmodified polyvinyl alcohol as the material of the alignment film. The modified polyvinyl alcohol described in paragraph Nos. [0071] to [0095] of Japanese Patent No. 3907735 can also be used. You may use the modified polyvinyl alcohol which has a polymeric group.

The alignment film that can be used in the present invention may be a photo-alignment film or an alignment film having a rubbing treatment surface that has been subjected to a rubbing treatment. In the present invention, a general rubbing processing method can be used. For example, it can be carried out by rubbing the surface of the alignment film with a rubbing roll. In an embodiment in which an alignment film is continuously formed on a support made of a long polymer film, the rubbing treatment direction (rubbing direction) is coincident with the longitudinal direction of the support from the viewpoint of manufacturing suitability. Is preferred.
The same applies when the first optically anisotropic layer is formed directly on the surface of the polarizing film.

  Next, the first optical anisotropic layer forming composition is applied (usually applied) to the surface of the alignment film or polarizing film. Application methods include known methods such as curtain coating, dip coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar method. It is done.

  The first composition for forming an optically anisotropic layer essentially comprises a liquid crystal compound, and a polymerization initiator, a polymerizable compound, a solvent, and the like are blended as necessary. Furthermore, it is preferable to mix a leveling agent or a compound having a hydroxyl group in the lateral direction as described above.

The liquid crystal compound for forming the first optically anisotropic layer may be a rod-like liquid crystal compound or a disk-like liquid crystal compound, and a rod-like liquid crystal compound is more preferable. When the first optically anisotropic layer is a rod-like liquid crystal compound, the second optically anisotropic layer is preferably a rod-like liquid crystal compound, and when the first optically anisotropic layer is a discotic liquid crystal compound, the second The optically anisotropic layer is preferably a discotic liquid crystal compound. As the liquid crystal phase of the first optically anisotropic layer, it is preferable to develop a smectic phase. In a compound capable of taking both a nematic phase and a smectic phase, it should be handled in a smectic phase state by orientation control such as heat. Is preferred.
The liquid crystal compound for forming the first optically anisotropic layer is preferably a liquid crystal compound exhibiting a smectic phase liquid crystal state, and more preferably a compound represented by the following general formula (I).
Formula (I): Q1-SP1-X1-M-X2-SP2-Q2
(In the general formula (I), Q1 and Q2 each represent a hydrogen atom, a halogen atom, a cyano group or a polymerizable group, at least one of Q1 and Q2 represents a polymerizable group; and SP1 and SP2 are each a single bond or Represents a spacer group; X1 and X2 each represent a linking group; M represents a mesogenic group.)

  In general formula (I), Q1 and Q2 are each independently a hydrogen atom, a cyano group, a halogen atom or a polymerizable group, and at least one of Q1 and Q2 is a polymerizable group. The polymerizable group is preferably capable of addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the polymerizable group is preferably a functional group capable of addition polymerization reaction or condensation polymerization reaction. . Examples of the polymerizable group are shown below.

The polymerizable groups Q1 and Q2 are each preferably an unsaturated polymerizable group (Q-1 to Q-7), an epoxy group (Q-8) or an aziridinyl group (Q-9), or an oxetanyl group, The unsaturated unsaturated polymerizable group (Q-1 to Q-6) or an epoxy group is more preferable. Examples of the ethylenically unsaturated polymerizable group (Q-1 to Q-6) further include the following (Q-101) to (Q-106). Among these, (Q-101) and (Q-102) are preferable.
In the formula, Rq1 is a hydrogen atom, an alkyl group, or an aryl group, Rq2 is a substituent, and n is an integer of 0-4. Rq1 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, still more preferably. A hydrogen atom or a methyl group. As the substituent represented by Rq2, those exemplified as examples of the substituents Ra, Rb and Rc described later can be preferably used. n is preferably an integer of 0 to 2, more preferably 0 or 1.

In general formula (I), SP1 and SP2 are each independently a single bond or a spacer group. SP1 and SP2 are each independently a divalent linking group selected from the group consisting of a single bond, —O—, —S—, —CO—, —NR ² —, a divalent chain group, and combinations thereof. It is preferable that R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom.

The divalent chain group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group or a substituted alkynylene group. An alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and an alkenylene group are more preferred. The alkylene group may have a branch. The number of carbon atoms in the alkylene group is preferably 1 to 12, more preferably 2 to 10, and most preferably 2 to 8. The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent of the substituted alkylene group include an alkoxy group and a halogen atom. The alkenylene group may have a branch. The alkenylene group has preferably 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkenylene part of the substituted alkenylene group is the same as the above alkenylene group. Examples of the substituent of the substituted alkenylene group include an alkoxy group and a halogen atom. The alkynylene group may have a branch. The number of carbon atoms of the alkynylene group is preferably 2 to 12, more preferably 2 to 10, and most preferably 2 to 8. The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent of the substituted alkynylene group include an alkoxy group and a halogen atom. In the divalent chain group, one or more non-adjacent CH ₂ groups are —O—, —C (═O) —O—, —O—C (═O) —, —O—C. (═O) —O—, —C (═O) —, and —S— may be substituted. The total number of carbon atoms of the spacer group is preferably 1 or more, more preferably 2 to 30, and still more preferably 4 to 20.

In general formula (I), X1 and X2 each represent a linking group. X1 and X2 are each independently selected from the group consisting of a single bond, —O—, —S—, —C (═O) —, —NR ² — (wherein R ² is the same as above), and combinations thereof. It is preferable that it is a bivalent coupling group. More preferably, a single bond, —O—, —C (═O) —O—, —O—C (═O) —, —C (═O) —NH—, —NH—C (═O) — or -O-C (= O) -O-.

In general formula (I), when Q1 or Q2 represents a polymerizable group, preferred examples of -SP1-X1- or -X2-SP2- include the following groups, but are not limited thereto. Absent. In the following specific examples, “*” is a binding site with Q1 or Q2.

  In the above general formula, n and m are each an integer of 1 or more. n is preferably an integer of 1 to 20, and more preferably an integer of 2 to 10. m is preferably an integer of 1 to 10, and more preferably an integer of 1 to 6.

  In General Formula (I), when Q1 or Q2 is a hydrogen atom or a halogen atom, -SP1-X1- or -X2-SP2- bonded to the hydrogen atom or the halogen atom may have 1 carbon atom which may be substituted. To an alkyl group having from 1 to 10 or an optionally substituted alkoxy group having from 1 to 10 carbon atoms.

  In general formula (I), when Q1 or Q2 represents a cyano group, -SP1-X1- or -X2-SP2- bonded to the cyano group is preferably a single bond.

In general formula (I), M is a mesogen represented by the following general formula (I-1).
Formula (I-1):
-(A0-Z0) n1-X0-SP0-X0- (A0-Z0) n2-

  In the formula, A0 represents a divalent ring structure, and 1,4-phenylene group, 1,4-cyclohexylene group, 2,5-pyridyl group, and 2,5-pyrimidyl group are preferable. These rings may have a substituent. A0 is more preferably a 1,4-phenylene group. From the viewpoint of facilitating mixing with other materials and improving solubility in a predetermined solvent, at least one ring preferably has a substituent.

  The kind of the substituent can be appropriately selected according to the desired physical properties. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. , An alkylthio group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, carbon An alkyl-substituted carbamoyl group having 2 to 6 atoms and an amide group having 2 to 6 carbon atoms are included. More preferably, a halogen atom, a cyano group, an alkyl group having 1 to 3 carbon atoms, a halogen-substituted alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and 2 to 2 carbon atoms. 4 acyloxy groups.

  Z0 is a single bond, —O—CO—, —CO—O—, —CH═CH—, —CH═N—, —N═CH—, —CH═CH—CO—O—, —O—CO. —CH═CH— and —O—CO—O— are represented, preferably a single bond, —O—CO—, and —CO—O—.

  SP0 is a single bond or a divalent spacer group, and its preferred range is the same as SP1 described above. X0 is a divalent linking group, and its preferred range is the same as X1 described above.

  n1 and n2 are each an integer of 1 to 4, and a plurality of A0 and Z0 may be the same or different from each other.

The compound represented by the general formula (I) is preferably a compound represented by the general formula (II).
Formula (II): Q1-SP1-X1-ABC- (D) m1-X2-SP2-Q2

In general formula (II), Q1 and Q2 are each independently a hydrogen atom, a cyano group, a halogen atom or a polymerizable group, and at least one of Q1 and Q2 is a polymerizable group. The detailed description and preferred range of the polymerizable group are the same as those described in the general formula (I).
m1 represents an integer of 1 to 5.

  In general formula (II), SP1 and SP2 are each a single bond or a spacer group, and X1 and X2 are each a linking group. Detailed descriptions and preferred ranges of SP1, SP2, X1 and X2 are the same as those described in the general formula (I).

  In the general formula (II), A, B, C and D each represent a divalent group selected from the following formulas IIa, IIb and IIc.

In the formula, R ^a , R ^b and R ^c each represent a substituent, na, nb and nc each represent an integer of 0 to 4, and when na, nb and nc are each an integer of 2 or more, there are plural Ra, Rb and Rc may be the same or different.

  When the compound of the general formula (II) includes a plurality of ester bonds (—C (═O) O— or —OC (═O) —), the order of the arrangement of the atoms of the plurality of ester bonds is the same. When it exists, it becomes easy to form a smectic phase. In the formula, the structure in which D is IIa and X2 is a single bond is equal to the structure in which D is IIc and X2 is —C (═O) O—. , D is IIa, and X2 is a single bond. A structure in which D is IIb and X2 is a single bond and a structure in which D is IIc and X2 is —OC (═O) — are also considered to be the former structure.

  In general formula (II), at least one of A, B, C and D preferably has a substituent (that is, at least one of na, nb and nc is an integer of 1 or more). Preferably). By introducing a substituent, mixing with other materials can be facilitated, and solubility in a predetermined solvent can be improved, so that a liquid crystal composition can be easily prepared. Further, the phase transition temperature can be changed by changing the type of the substituent. The kind of the substituent can be appropriately selected according to the desired physical properties. Examples of the substituent represented by each of Ra, Rb and Rc include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and a carbon atom. An alkoxy group having 1 to 5 carbon atoms, an alkylthio group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, and 2 to 6 carbon atoms Examples include alkoxycarbonyl groups, carbamoyl, alkyl-substituted carbamoyl groups having 2 to 6 carbon atoms, and amide groups having 2 to 6 carbon atoms. More preferably, a halogen atom, cyano, an alkyl group having 1 to 3 carbon atoms, a halogen-substituted alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or 2 to 4 carbon atoms. Of the acyloxy group.

In the general formula (II), when m1 is 0, A, B, and C are preferably composed of only IIa or a combination of IIa and IIc. As -ABC-, preferred combinations are as follows. In the following examples, the order of arrangement of atoms of a plurality of ester bonds is the same as each other, and it is considered that the molecular structures are easy to form a smectic phase. In the formula, as described above, a plurality of R ^a , R ^b , R ^c , na, nb and nc may be the same as or different from each other.

  When m1 is 1 in general formula (II), at least two of A, B, C and D are divalent groups represented by formula IIa, or at least two are represented by formula IIb. It is preferable that it is a divalent group. Further, A, B, C and D are preferably composed of IIa alone or a combination of IIa and IIc, and more preferably composed of a combination of IIa and IIc.

In the general formula (II), when m1 is 1, a preferred combination as -A-B-C-D- is as follows. In the following examples, the order of arrangement of atoms of a plurality of ester bonds is the same as each other, and it is considered that the molecular structures are easy to form a smectic phase. In the formula, as described above, a plurality of R ^a , R ^b , R ^c , na, nb and nc may be the same as or different from each other.

The compound represented by the general formula (I) is more preferably a compound represented by the general formula (III).
General formula (III): Q1-SP1-X1-A1-B1-C1- (D1) m1-Y1-L-Y2- (D2) m2-C2-B2-A2-X2-SP2-Q2-Q2

  In general formula (III), Q1 and Q2 are each independently a hydrogen atom, a cyano group, a halogen atom or a polymerizable group, and at least one of Q1 and Q2 is a polymerizable group. The detailed description and preferred range of the polymerizable group are the same as those described in the general formula (I).

  In general formula (III), SP1 and SP2 are each a single bond or a spacer group, and X1, X2, Y1, and Y2 are each a linking group. Detailed descriptions and preferred ranges of SP1, SP2, X1 and X2 are the same as those described in the general formula (I). Detailed descriptions and preferred ranges of Y1 and Y2 are the same as those described for X1 and X2 in the aforementioned general formula (I).

In the general formula (III), L is a spacer group containing a chain structure having 4 or more atoms, and includes —O—, —S—, —CO—, —NR ² —, divalent chain groups, and their A divalent linking group selected from the group consisting of combinations is preferred. R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. The divalent chain group has the same meaning as that described as the divalent chain group of SP1 and SP2 in the general formula (I), and the preferred range is also the same. L preferably comprises a divalent chain _{group, - (CH 2) n -} , - (C a H 2a X) n-, or is preferably a combination of two or more thereof. However, n is an integer of 2 or more (preferably 2 to 20), and in the compound represented by the general formula (III), when a plurality of n is present, each n may be the same or different. Also good. a is an integer of 2 or more (preferably 2 to 16). X is —O—, —CO—O—, —O—CO—, —O—CO—O—, —CO— or —S—, preferably —O— or —S—. The hydrogen atom H in the formula may be substituted with a C1-C6 alkyl group such as methyl or ethyl, and a part of the C—C bond in the formula is substituted with a C═C bond. May be.

In the general formula (III), -Y1-L-Y2- is preferably a group selected from the following group (III-1).
Group (III-1):

  In the above formula, n and m are each an integer of 1 or more, and l is an integer of 0 or more. Preferably, n is an integer of 1-20, m is an integer of 1-5, and l is an integer of 0-6.

  In the general formula (III), A1, A2, B1, B2, C1, C2, D1 and D2 each represent a divalent group selected from the following formulas IIa, IIb and IIc.

In the formula, R ^a , R ^b and R ^c each represent a substituent, na, nb and nc each represent an integer of 0 to 4, and when na, nb and nc are each an integer of 2 or more, there are plural Ra, Rb and Rc may be the same or different.

In the general formula (III), by introducing substituents in the formulas IIa, IIb and IIc, that is, Ra, Rb and Rc, into 1, A2, B1, B2, C1, C2, D1 and D2, Mixing with other materials can be facilitated, and the solubility in a predetermined solvent can be improved, so that the liquid crystal composition can be easily prepared. Further, the phase transition temperature can be changed by changing the type of the substituent. The kind of the substituent can be appropriately selected according to the desired physical properties. The substituents represented by R ^a , R ^b and R ^c are the same as those described in the general formula (II).

  When the compound of the general formula (III) includes a plurality of ester bonds (—C (═O) O— or —OC (═O) —), the order of arrangement of the atoms of the plurality of ester bonds is the same. When it exists, it becomes easy to form a smectic phase. In the formula, the structure in which D1 is IIa and Y1 is a single bond is equal to the structure in which D1 is IIc and Y1 is —C (═O) O—. , D1 is IIa, and Y1 is regarded as a single bond. A structure in which D1 is IIb and X2 is a single bond and a structure in which D1 is IIc and X2 is —OC (═O) — are also considered to be the former structure.

  In general formula (III), m1 and m2 each independently represents 0 or 1.

In the general formula (III), when m1 is 0, the corresponding A1, B1, and C1 are preferably composed only of IIa or a combination of IIa and IIc. A preferred combination as -A1-B1-C1- is the same as the preferred range of -ABC- in the above general formula (II). As described above, a plurality of R ^a , R ^b , R ^c , na, nb and nc may be the same as or different from each other.

  In the general formula (III), when m2 is 0, preferred ranges of A2, B2, and C2 are the same as those of A1, B1, and C1 described above. When m1 and m2 are both 0, -A1-B1-C1- and -A2-B2-C1- may be the same or different, but are preferably the same in terms of synthesis.

  In the general formula (III), when m1 is 1, A1, B1, C1, and D1 each represent a divalent group selected from the aforementioned formulas IIa, IIb, and IIc, and at least of A1, B1, C1, and D1 Two are divalent groups represented by Formula IIa, or at least two are divalent groups represented by Formula IIb. Similarly, when m2 is 1 in the general formula (III), A2, B2, C2 and D2 each represent a divalent group selected from the aforementioned formulas IIa, IIb and IIc, but in A2, B2, C2 and D2, At least two of them are divalent groups represented by Formula IIa, or at least two are divalent groups represented by Formula IIb.

In general formula (III), when m1 is 1, A1, B1, C1 and D1 are preferably composed of IIa alone or a combination of IIa and IIc, and a combination of IIa and IIc. More preferred. A preferred combination as -A1-B1-C1-D1- is the same as the preferred range of -A-B-C-D- in the aforementioned general formula (II). In the formula, as described above, a plurality of R ^a , R ^b , R ^c , na, nb and nc may be the same as or different from each other.

  When m2 is 1 in the general formula (III), a preferable combination is the same as -A1-B1-C1-D1- as -D2-C2-B2-A2-. When m1 and m2 are both 1, -A1-B1-C1-D1- and -D2-C2-B2-A2- may be the same or different, but are preferably the same in synthesis. .

  In the general formula (III), m1 and m2 may be different, but are preferably the same in the synthesis.

  Examples of the compounds represented by the above general formula (II) and general formula (III) include the compounds described in paragraphs [0033] to [0039] of JP2008-19240A, and JP2008-214269A. Examples include compounds described in paragraphs [0037] to [0041] of the publication, compounds described in paragraphs [0033] to [0040] of JP-A-2006-215437, and structures shown below. It is not limited to.

  The compounds represented by the general formulas (I) to (III) can be synthesized by combining known synthesis reactions. That is, various literatures (see, for example, Method der Organischen Chemie (Houben-Weyl), Some specific methods (by Thime-Verlag, Stuttgart), synthetic chemistry course and new experimental chemistry course). As synthesis methods, U.S. Pat. Nos. 4,683,327, 4,983,479, 5,622,648, 5,770,107, International Patents (WO) 95/22586, 97/00600, 98/47979, and British Patent 2297549. The description of each specification of the issue can also be referred to.

  The compounds represented by the general formulas (I) to (III) are more preferably liquid crystal compounds that transition to a smectic phase in a temperature range of 80 to 180 ° C. (more preferably 70 to 150 ° C.). If the transition to the smectic phase is possible within such a temperature range, an anisotropic material utilizing the anisotropy expressed by the smectic phase can be stably produced without excessive heating or excessive cooling. This is preferable.

Moreover, as a liquid crystal compound used for the 1st optically anisotropic layer in this invention, the reactive mesogen compound of the paragraph numbers 0013-0030 of Unexamined-Japanese-Patent No. 10-319408, JP 2000-514202 A Examples include the reactive mesogen compounds described in the paragraph numbers (especially the compounds described below), the photochemical oligomer-forming or polymerizable liquid crystals described in JP-T-2001-527570, and particularly the compounds described in the Examples. Is incorporated herein by reference.
Further, the liquid crystal compound used in the first optically anisotropic layer in the present invention may be a side chain type liquid crystal oligomer described in JP-A-6-331826.

Examples of the discotic liquid crystal compound used for the first optically anisotropic layer include compounds represented by the general formula (II) described in JP-A-2008-050553, and the preferred range is also synonymous.
Hereinafter, although the specific example of the disk-shaped liquid crystal compound used for this invention is given and demonstrated in detail, this invention is not limited at all by the following specific examples. Regarding the following compounds, unless otherwise specified, the number in parentheses () indicates the exemplified compound (x).

(Here, Ra, Rb and Rc are groups represented in the following table, respectively.)

  The first composition for forming an optically anisotropic layer used in the present invention preferably contains at least one compound represented by the above general formulas (I) to (III), preferably 80 to 180 ° C. More preferably, it is a liquid crystal composition capable of transitioning to a smectic phase in a temperature range of 70 to 150 ° C.

  The first composition for forming an optically anisotropic layer used in the present invention may contain only one type of liquid crystal compound, or may contain two or more types. Further, other liquid crystal compounds may be included without departing from the spirit of the present invention. For example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, It may contain a rod-like liquid crystal compound selected from tolanes and alkenylcyclohexylbenzonitriles.

  The amount of the liquid crystal compound in the first composition for forming an optically anisotropic layer is preferably from 50 to 98 mass%, more preferably from 70 to 95 mass%, based on the total solid content.

Furthermore, the first composition for forming an optically anisotropic layer used in the present invention may contain a photopolymerization initiator. The photopolymerization initiator is preferably blended when the liquid crystal compound has a polymerizable group or contains a polymerizable compound. Specific examples of the photopolymerization initiator include α-carbonyl compounds (described in the specifications of US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in the specification of US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. An acyloin compound (described in US Pat. No. 2,722,512), a polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of a triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), oxadiazole compounds (US Pat. No. 4,221,970), acylphosphine oxide compounds (JP-B 63) -40799 public No. 5-29234, JP-A-10-95788, and JP-A-10-29997), the contents of which are incorporated herein.
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 first optically anisotropic layer forming composition. preferable.

The first composition for forming an optically anisotropic layer used in the present invention may contain a polymerizable compound.
The polymerizable compound used together with the liquid crystal compound is not particularly limited as long as it is compatible with the liquid crystal compound and does not significantly change the tilt angle or disturb the alignment of the liquid crystal compound. Among these, compounds having a polymerization active ethylenically unsaturated group such as a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group are preferably used.
As the polymerizable compound, it is particularly preferable to use a polymerizable compound having two or more reactive functional groups because an effect of improving the adhesion between the alignment film and the optically anisotropic layer can be expected. The polymerizable compound may be a polymer, but is preferably a monomer (for example, a molecular weight of 2000 or less).
One type of polymerizable compound may be contained in the first composition for forming an optically anisotropic layer, or two or more types thereof may be contained. The content of the polymerizable compound is generally in the range of 0.5 to 50% by mass and preferably in the range of 1 to 30% by mass with respect to the liquid crystal compound.

  The first optically anisotropic layer forming composition may contain a solvent. As a solvent for the composition, 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, cyclohexanone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Only one type of solvent may be used, or two or more types of organic solvents may be used in combination. The solvent is preferably adjusted so that the solid concentration of the composition is 10 to 50% by mass.

  In addition, the details of the method for producing the first optically anisotropic layer can be referred to the descriptions in JP-A-2008-225281 and JP-A-2008-026730.

<< Method for Producing Second Optically Anisotropic Layer >>
Next, the detail of the manufacturing method of the 2nd optically anisotropic layer in this invention is described. The second optical anisotropic layer can be formed by applying the second composition for forming an optical anisotropic layer to the surface of the first optical anisotropic layer. As described above, even if the second composition for forming an optical anisotropic layer is applied to the surface of the first optical anisotropic layer by a conventional method, the second optical anisotropic satisfying a predetermined order parameter The conductive layer cannot be substantially manufactured. In the present invention, as described above, a leveling agent is blended in the first optical anisotropic layer to flatten the surface, or a vertical alignment agent is blended in the second optical anisotropic layer to control the orientation. Or by adding a compound having a hydroxyl group in the lateral direction to the first optical anisotropic layer, or by combining them, the second optical anisotropic layer is formed on the surface of the first optical anisotropic layer. Has been successful. The method for producing the second optically anisotropic layer comprises applying the second optically anisotropic layer forming composition directly to the surface of the first optically anisotropic layer, and applying the second optically anisotropic layer. Except for the composition of the composition for forming the isotropic layer, the description of the method for producing the first optically anisotropic layer can be referred to.

  The second composition for forming an optically anisotropic layer essentially comprises a liquid crystal compound, and a polymerization initiator, a leveling agent, a polymerizable compound, a solvent, and the like are blended as necessary. Furthermore, as described above, it is preferable to blend a vertical alignment agent.

The liquid crystal compound for forming the second optically anisotropic layer may be a rod-like liquid crystal compound or a disk-like liquid crystal compound, and a rod-like liquid crystal compound is more preferable.
The liquid crystal compound for forming the second optically anisotropic layer is preferably a liquid crystal compound exhibiting a smectic phase or a nematic phase liquid crystal state, and more preferably a liquid crystal compound exhibiting a nematic phase liquid crystal state.
As the liquid crystal compound exhibiting a smectic phase liquid crystal state, the liquid crystal compounds described in the column of the first composition for forming an optically anisotropic layer are preferably used.
Examples of the compound exhibiting a nematic phase include compounds represented by general formula (I) described in JP-A-2008-297210 (particularly compounds described in paragraphs 0034 to 0039), JP-A-2010-84032 A compound represented by the general formula (1) described above (in particular, a compound described in paragraphs 0067 to 0073) or the like can be used.
In the present invention, it is particularly preferably at least one compound selected from the group consisting of a compound represented by the following general formula (IA) and a compound represented by the following general formula (IIA).

(Wherein R _{1 to} R ₄ are each independently — (CH ₂ ) _n —OOC—CH═CH ₂ , n is an integer of 1 to 5. X and Y are each independently a hydrogen atom. Or represents a methyl group.)

  From the viewpoint of inhibiting crystal precipitation, in the general formula (IA) or (IIA), X and Y preferably represent a methyl group. From the viewpoint of showing properties as a liquid crystal, n is an integer of 1 to 5, and an integer of 2 to 5 is more preferable.

  The second composition for forming an optically anisotropic layer used in the present invention may contain only one type of liquid crystal compound, or may contain two or more types. Further, other liquid crystal compounds may be included without departing from the spirit of the present invention. For example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, It may contain a rod-like liquid crystal compound selected from tolanes and alkenylcyclohexylbenzonitriles.

  The amount of the liquid crystal compound in the second optically anisotropic layer forming composition is preferably 50 to 98 mass%, more preferably 70 to 95 mass% of the total solid content.

  Furthermore, the second composition for forming an optically anisotropic layer may contain a polymerization initiator, a leveling agent, a polymerizable compound, a solvent, and the like. For these details, the description regarding the first composition for forming an optically anisotropic layer can be referred to, and the preferred range, blending amount, and the like are also the same.

<Phase difference film>
The retardation film of the present invention may be composed only of the first optical anisotropic layer and the second optical anisotropic layer, or in order to form a support or the first optical anisotropic layer. You may have the alignment film etc. which were used.

  There is no restriction | limiting in particular about a support body. Various polymer films can be used. An example is a polymer film that is transparent and has small optical anisotropy, but is not limited thereto. Here, that the support is transparent means that the light transmittance is 80% or more. Further, the small optical anisotropy means that the in-plane retardation (Re (550)) is, for example, 20 nm or less, and preferably 10 nm or less. The transparent support may be a long and roll-shaped shape, or a size of the final product, for example, a rectangular sheet shape. It is preferable to use a long polymer film wound up in a roll shape as a support, continuously form an alignment film and an optically anisotropic layer, and then cut into a required size.

Examples of polymer films that can be used as the support include films of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, and the like. A cellulose acylate film is preferred, and a cellulose acetate film is more preferred. When a cellulose acylate film is used, a decrease in front contrast is further suppressed.
Moreover, when comprising the aspect which serves as a below-mentioned support body and polarizer, you may use polyvinyl alcohol for a polymer.

In the retardation film of the present invention, the total thickness of the first optical anisotropic layer and the second optical anisotropic layer is preferably 0.6 to 6 μm, and preferably 1.0 to 5.0 μm. More preferably, it is more preferably 1.5 to 3.0 μm. By setting it as such a range, a thinner film can be achieved.
In addition, the retardation film of the present invention has a total thickness (when serving also as a protective film for a polarizing plate, the total thickness from the layer adjacent to the polarizing film to the second optically anisotropic layer, for example, FIG. To 3) is preferably 40 μm or less, more preferably 35 μm or less, further preferably 10 μm or less, and particularly preferably 3 μm or less. In the present invention, in particular, since the retardation film can be formed without using the support and the alignment film, the total thickness of the retardation film can be reduced to 3 μm or less. About a lower limit, it is 0.6 micrometer or more, and 1 micrometer or more is preferable.

  The retardation film of the present invention is preferably used as a protective film for a polarizing plate. In addition, the retardation film of the present invention may be incorporated as a retardation film separately from the polarizing plate. In this case, it is more preferable that the retardation film is disposed between the polarizing film on the front side and the liquid crystal cell. Further, it may be disposed between the rear polarizing film and the liquid crystal cell. The front side in the present invention refers to the viewing side of the liquid crystal display device.

<Polarizing plate>
The polarizing plate of the present invention has a polarizing film and the retardation film of the present invention, and may further have a protective film on the surface of the polarizing film on which the retardation film of the present invention is not provided. . The polarizing plate of the present invention is preferably used as a protective film for the polarizing plate on the front side. Further, when incorporated in a liquid crystal display device, it is more preferable that the retardation film of the present invention is disposed between the polarizing film on the side close to the liquid crystal cell and the liquid crystal cell on the front side.

Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine-based polarizing film and the dye-based polarizing film can be generally produced using a polyvinyl alcohol film.
The protective film on the side of the polarizing film on which the retardation film of the present invention is not provided is usually a polymer film. An example of such a protective film is a cellulose acylate film.
The protective film and retardation film used in the present invention have a hydrophilic property on the surface, that is, the surface to be bonded to the polarizing film. It can be improved. In the case where the retardation film of the present invention is directly provided on the surface of the polarizing film, the saponification treatment can be omitted.

Hereinafter, the preferable aspect of the polarizing plate of this invention is demonstrated using figures. Needless to say, the configuration of the polarizing plate of the present invention is not limited thereto. In addition, the scale in the following diagram may not match the scale of an actual polarizing plate.
1 to 3 are examples showing the constitution of the polarizing plate of the present invention, wherein 1 is a polarizing film, 2 is a protective film for the polarizing film, 3 is a retardation film of the present invention, and 4 is a first film. , 5 represents a second optical anisotropic layer, 6 represents a support for a retardation film, and 7 represents an alignment film. The arrow in the polarizing film 1 in FIG. 1 indicates the direction of the polarization axis, the symbol in the optically anisotropic layer 4 of the first optical indicates the direction of the slow axis, and is orthogonal to the arrow of the polarizing film 1. It means that. The arrow of the alignment film 7 indicates the rubbing direction of the alignment film. The same applies to the following figures.

FIG. 1 shows an embodiment in which a protective film 2 is bonded to one surface of a polarizing film 1 and a retardation film 3 of the present invention is bonded to the other surface. Bonding can be performed using an adhesive, a pressure-sensitive adhesive, or glue (the adhesive layer and the like are not shown).
In FIG. 1, a retardation film 3 is formed by forming an alignment film 7 on the surface of a support 6, and providing a first optical anisotropic layer 4 and a second optical anisotropic layer 5 on the surface. Yes. The rubbing direction of the alignment film 7 is preferably provided so as to be orthogonal to the longitudinal direction of the polarizing film.

In FIG. 2, the protective film 2 is provided on one surface of the polarizing film 1, and the first optical anisotropic layer 4 and the second optical anisotropic layer 5 are provided in this order directly on the other surface. In FIG. 2, since the retardation film 3 of the present invention comprises only the first optical anisotropic layer 4 and the second optical anisotropic layer 5, the thickness of the retardation film can be extremely reduced.
In the case of the embodiment of FIG. 2, it is preferable to provide a first optical anisotropic layer by rubbing the surface of the polarizing film 1. In FIG. 2, the hard coat layer 8 is provided on the surface of the protective film 2.
The hard coat layer is preferably a layer formed by curing a polymerizable compound. Specifically, the layer which applied and hardened the composition containing polyfunctional (meth) acrylate, a polymerization initiator, and a solvent is illustrated. The thickness of the hard coat layer is preferably about 1 to 10 μm. By providing such a hard coat layer, the protective film can be hardly damaged even if the thickness of the protective film or the like is reduced. Furthermore, if a problem such as suitability for production does not occur, the protective film 2 can be omitted and a hard coat layer can be provided directly on the polarizing film, so that a thinner polarizing plate can be obtained.

  FIG. 3 shows that the protective film 2 is formed on one surface of the polarizing film 1 and the alignment film 7 is formed on the surface of the other surface, and the first optical anisotropic layer 4 and the second optical anisotropic are formed on the surface. The phase difference film 3 is formed by providing the conductive layer 5. The rubbing direction of the alignment film 7 is preferably provided so as to be orthogonal to the longitudinal direction of the polarizing film. Further, in FIG. 3, a hard coat layer 8 is provided on the surface of the protective film.

<Liquid crystal display device>
The present invention also relates to a liquid crystal display device having the retardation film or polarizing plate of the present invention. A driving mode is not particularly selected as the liquid crystal display device, but a TN type (Twisted Nematic), an OCB type (Optically Compensated Bend), a VA type (Virtical Alignment), etc. can be used, and in particular, an IPS type (In-Plane Switching). It can be preferably used as a lateral electric field type (hereinafter sometimes referred to as IPS mode) represented by FFS type (Fringe Field Switching), PLS type (Plane to Line Switching) and the like. In the present invention, any of a transmissive type, a reflective type, and a transflective liquid crystal display device may be used.

  IPS type (hereinafter also referred to as IPS mode) liquid crystal display devices include, for example, Japanese Patent Application Laid-Open Nos. 2003-15160, 2003-75850, 2003-295171, 2004-12730, and 2004-12731. JP, 2005-106967, JP, 2005-134914, JP, 2005-241923, JP, 2005-284304, JP, 2006-189758, JP, 2006-194918, JP, 2006-220680, JP2007-140353, JP2007-178904, JP2007-293290, JP2007-328350, JP2008-3251, JP2008-39806, JP2008-40291, Special JP 2008-65196, JP 2008-76849 It can also be used those described in JP-like JP 2008-96815.

  An FFS type (hereinafter also referred to as FFS mode) liquid crystal display device includes 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. Regarding the FFS type liquid crystal cell, for example, refer to the descriptions in JP-A-2001-100193, JP-A-2002-14374, JP-A-2002-182230, JP-A-2003-131248, JP-A-2003-233083, and the like. it can.

FIG. 4 shows an example of the configuration of the liquid crystal display device of the present invention. 4, 1 to 8 are common to FIGS. 1 to 3, and the description of FIG. 3 can be referred to for details. In FIG. 4, 9 is a liquid crystal cell, 10 is a rear polarizing plate, 11 is a rear polarizing film, 12 is a protective film for the rear polarizing film, 13 is an alignment film, and 14 is an alignment film. An optically anisotropic layer is shown. The absorption axes of the polarizing film 1 on the front side and the polarizing plate 11 on the rear side are orthogonal to each other. Further, the liquid crystal display device shown in FIG. 4 has an optically anisotropic layer 14 between the polarizing film 11 on the rear side and the liquid crystal cell 9. The optically anisotropic layer 14 can be formed, for example, by providing the alignment film 13 on the surface of the polarizing film 11 and applying and curing the composition for forming an optically anisotropic layer on the surface of the alignment film 13. In the embodiment of FIG. 4, the optically anisotropic layer 14 (optical film) has an in-plane retardation (Re (550)) of 30 to 120 nm at a wavelength of 550 nm, and a retardation in the thickness direction (Rth) at a wavelength of 550 nm. (550)) is preferably 20 to 100 nm. Furthermore, the optically anisotropic layer 14 is more preferably an optically anisotropic layer in which a liquid crystal compound is tilted and aligned. In this case, the tilt orientation angle is preferably −1.5 to 3 ° which is the same tilt angle as the pretilt angle of the driving liquid crystal in the liquid crystal cell and the same tilt angle. The liquid crystal compound is preferably a rod-like liquid crystal compound. Only one type of rod-shaped liquid crystal compound may be used, or two or more types may be used. This liquid crystal compound is also preferably used with a high degree of orientational order, as with the liquid crystal compound of the present invention.
By providing such an optically anisotropic layer 14 on the rear side to compensate the polarizing film, the birefringence component of each member other than the optically anisotropic layer of the liquid crystal display device is compensated, and the hue and the upper and lower A liquid crystal display device excellent in symmetry can be provided.

In the present specification, Re (λ) and Rth (λ) respectively represent in-plane retardation and retardation in the thickness direction at a wavelength λ. Re (λ) is measured with KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.) by making light of wavelength 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.
Rth (λ) is Re (λ) with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotary axis) (if there is no slow axis, the film surface 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). Based on the value, the assumed value of the average refractive index, and the input film thickness value, Re and Rth can also be calculated from the following expressions (A) and (III).

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.
Rth = ((nx + ny) / 2−nz) × d (formula (III))

  When the film to be measured is a film that cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method. Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotary axis) from −50 ° with respect to the film normal direction. 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 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 the main retardation 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.

  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) Production of a liquid crystal display device having a layer configuration a (a liquid crystal display device having the polarizing plate of FIG.
<Alkali saponification treatment>
The following alkali saponification treatment was performed on one side of a cellulose film (manufactured by FUJIFILM Corporation, zero retardation tack, ZRF25, thickness: 25 μm).
After passing the film (ZRF25) on a dielectric heating roll having a temperature of 60 ° C. and raising the film surface temperature to 40 ° C., an alkali solution (S-1) having the composition shown below was used using a rod coater. It apply | coated with the application quantity of 17 mL / m < ² >, and it was made to retain for 10 second under the steam type far-infrared heater by Noritake Co., Ltd. which was heated to 110 degreeC. Subsequently, 2.8 mL / m ^{2 of} distilled water was similarly applied using a rod coater, and then water washing with a fountain coater and draining with an air knife were repeated three times. Single-sided saponification film A-1 was produced.

<< Alkaline solution (S-1) composition >>
Potassium hydroxide 8.6 parts by weight Water 24.1 parts by weight Isopropanol 56.3 parts by weight Surfactant (K-1: C ₁₆ H ₃₃ O (CH ₂ CH ₂ O) ₁₀ H) 1.0 part by weight Propylene glycol 10.0 parts by mass

<< Physical Properties of Alkaline Solution (S-1) >>
Surface tension 20mN / m
Viscosity 5.2 mPa · s

<Preparation of alignment film>
On the surface of the saponified film, 100 parts by mass of a compound represented by the following general formula polyvinyl alcohol (polyvinyl alcohol 1) and 5 parts by mass of a compound represented by T1 below, water: methanol = 75: 25 (mass ratio) A composition for preparing a polyvinyl alcohol layer was prepared by dissolving in a 4.0 mass% solution in the above solvent. Thereafter, this solution was applied with a wire bar coater # 8 and dried at 60 ° C. for 0.5 minutes. The film thickness of the obtained polyvinyl alcohol layer was 0.25 μm.
Polyvinyl alcohol 1 is a = 96, b = 2, and c = 2 in the polyvinyl alcohol. Ac represents an acetyl group.

  The obtained polyvinyl alcohol layer was rubbed on the surface of the polyvinyl alcohol layer in a direction perpendicular to the longitudinal direction of the film (ZRF25) to produce a polyvinyl alcohol alignment film.

<Preparation of first optically anisotropic layer>
The following composition was dissolved in a solution of methyl ethyl ketone: cyclohexanone = 86: 14 (mass ratio) and adjusted to 30% by mass.
Liquid crystal compounds described in the following table (any of α to ε) 100 parts by weight polymerization initiator J1 3 parts by weight polymerization initiator J2 1 part by weight leveling agent R1 0.8 parts by weight leveling agent R2 0.05 parts by weight acrylate monomer A1 5 parts by mass

<< Liquid Crystal α >>
80 parts by mass of the following compound B03
Compound B04 20 parts by mass The liquid crystal α has an NI point of 145 ° C., indicating a nematic phase.

<< Liquid Crystal β >>
Compound B01 80 parts by mass Compound B02 20 parts by mass
The NI point of liquid crystal β was 120 ° C., indicating a nematic phase.

<< Liquid crystal γ >>
Compound B03 60 parts by mass Compound B04 20 parts by mass Compound B02 20 parts by mass The liquid crystal γ had an NI point of 142 ° C., indicating a nematic phase.

<< Liquid Crystal ε >>
Compound A described in paragraph No. 0161 of JP2010-84032A

Polymerization initiator J1
Polymerization initiator J2
Leveling agent R1
Leveling agent R2
Acrylate monomer A1

The composition was applied with a wire bar coater selected according to the film thickness, dried at 70 ° C. for 2 minutes, and the rod-like liquid crystal compound was aligned (homogeneous alignment). After cooling this film to 40 ° C., using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, an illuminance of 190 mW / cm ² and an irradiation amount of 150 mJ The coated layer was cured by irradiating UV light of / cm ² . Then, it stood to cool to room temperature. The thickness of the obtained optically anisotropic layer is shown in the table.
Confirmation of homogeneous alignment is extinction when the alignment axis direction is aligned with the polarizer absorption axis in a crossed Nicol state under a polarizing microscope (0 °, 90 °), and changes in brightness at the angle between them. This was confirmed by having a maximum luminance in the 45 ° direction.

<Preparation of second optically anisotropic layer>
The following composition was dissolved in a solution of methyl ethyl ketone: cyclohexanone = 86: 14 (mass ratio) and adjusted to 30% by mass.
100 parts by mass of liquid crystal compound B01 + liquid crystal compound B02 (composition is 80:20 (mass ratio))
Polymerization initiator J1 3 parts by weight Polymerization initiator J2 1 part by weight leveling agent R1 0.4 part by weight leveling agent R2 0.05 part by weight acrylate monomer A1 5 parts by weight vertical alignment agent S1 1 part by weight vertical alignment agent S2 0.5 Parts by mass (however, in Comparative Example 5, the amount of the acrylate monomer A1 was changed from 5 parts by mass to 15 parts by mass)

Vertical alignment agent S1
Vertical alignment agent S2

The obtained composition was applied with a wire bar coater selected according to the film thickness, and heated in a thermostatic bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound (homeotropic alignment). Next, after cooling to 40 ° C., using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, an illuminance of 190 mW / cm ² and an irradiation amount of 300 mJ The coated layer was cured by irradiating UV light of / cm ² . Then, it stood to cool to room temperature.

  In this manner, a polyvinyl alcohol alignment film is formed on the film (ZRF25), a first optically anisotropic layer having homogeneous alignment is formed, and a second optically anisotropic layer having homeotropic alignment is further formed thereon. Was made.

The surface opposite to the second optically anisotropic layer of the laminate obtained above was bonded to a polyvinyl alcohol polarizing film (thickness 17 μm) using polyvinyl alcohol paste. At this time, the film was bonded so that the rubbing direction was orthogonal to the longitudinal direction of the polarizing film.
Furthermore, the cellulose acylate film A (protective film, film thickness of 25 μm) produced in the layer constitution b described later is applied to the surface of the polarizing film on which the second optical anisotropy is not bonded to polyvinyl alcohol (manufactured by Kuraray Co., Ltd.). , Polyvinyl alcohol-117H) 3% aqueous solution was used as an adhesive and bonded to a polarizing film.

<Production of liquid crystal display device>
<< Preparation of liquid crystal cell >>
Take out the liquid crystal panel from the iPad [trade name; manufactured by Apple Inc.] equipped with the IPS type liquid crystal cell, and remove the polarizing plate placed on the front side (display surface side) and rear side (backlight side) of the liquid crystal cell. The front glass surface of the liquid crystal cell was washed.

<< Preparation of rear polarizing plate >>
Alkali saponification treatment was performed in the same manner as above on one side of the zero retardation tack (manufactured by Fuji Film, ZRF25) and on one side of Fujitac TD60UL (thickness 60 μm). With these films, a polyvinyl alcohol polarizing film (thickness 17 μm) is sandwiched so that the alkali saponification surface is on the polyvinyl alcohol polarizing film side, and a 3% aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., polyvinyl alcohol-117H) is used as an adhesive. Was used to obtain a rear polarizing plate.

  The polarizing plate of the present invention was bonded to the front side of the display surface side surface of the IPS liquid crystal cell, and the rear side polarizing plate was bonded to the other side. At this time, the front side was bonded so that the side having the optically anisotropic layer was present, and the rear side was bonded so that the ZRF 25 was close to the liquid crystal cell. In this way, an IPS liquid crystal display device LCD was produced. The produced LCD was returned to the iPad taken out.

(2) Production of a liquid crystal display device having a layer configuration b (a liquid crystal display device having the polarizing plate of FIG. 2)
<Preparation of polarizing plate protective film>
The following core layer cellulose acylate dope composition was put into a mixing tank and stirred to dissolve each component to prepare a core layer cellulose acylate dope.
-------------------------------------------------- ---------------------
Cellulose acetate having an acetyl substitution degree of 2.88 100 parts by mass Ester oligomer 1 10 parts by mass Durability improver 1 4 parts by mass UV absorber 1 3 parts by mass Methylene chloride (first solvent) 438 parts by mass Methanol (second solvent) 65 Parts by mass
-------------------------------------------------- ---------------------
Ester oligomer 1
Durability improver 1
UV absorber 1

10 parts by mass of the following matting agent solution was added to 90 parts by mass of the core layer cellulose acylate dope to prepare an outer layer cellulose acetate solution.
-------------------------------------------------- ---------------------
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass Core layer cellulose acylate dope 1 part by mass
-------------------------------------------------- ---------------------

  Three layers of the core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides of the core layer cellulose acylate dope were simultaneously cast on a drum at 20 ° C. from the casting port. The film was peeled off at a solvent content of about 20% by mass, both ends in the width direction of the film were fixed with a tenter clip, and dried while being stretched 1.2 times in the lateral direction with a residual solvent of 3 to 15% by mass. . Thereafter, a cellulose acylate film having a thickness of 25 μm was produced by conveying between rolls of a heat treatment apparatus (cellulose acylate film A).

<Preparation of hard coat layer>
The following hard coat composition 1 is applied onto one surface of the cellulose acylate film A, then dried at 100 ° C. for 60 seconds, and ultraviolet rays are reduced to 1.5 kW and 300 mJ under the condition of 0.1% or less of nitrogen. Irradiated and cured to prepare a hard coat layer having a thickness of 5 μm. The film thickness was adjusted by using a slot die and adjusting the coating amount in a die coating method.

<< Hard Coat Composition 1 >>
Pentaerythritol triacrylate / pentaerythritol tetraacrylate (mass ratio 3: 2) Total 53.5 parts by mass Photopolymerization initiator J3 1.5 parts by mass Ethyl acetate 100 parts by mass

Photopolymerization initiator J3

<Saponification of film>
The produced cellulose acylate film A with hard coat was immersed in a 4.5 mol / L sodium hydroxide aqueous solution (saponification solution) adjusted to 37 ° C. for 1 minute, and then the film was washed with water, and then 0.05 mol / L. After being immersed in a sulfuric acid aqueous solution of L for 30 seconds, the solution was passed through a water washing bath. Then, draining with an air knife was repeated three times, and after dropping water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film.

<Preparation of polarizing film>
According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls, the film was stretched in the longitudinal direction, and a polarizing film having a longitudinal width of 1330 mm and a thickness of 15 μm was prepared.

<Lamination>
The polarizing film obtained above and the saponified film are coated with polyvinyl alcohol (made by Kuraray Co., Ltd., polyvinyl alcohol-117H) on the cellulose acylate film A side opposite to the hard coat layer of the film. Using a 3% aqueous solution as an adhesive, a polarizing film with a single-side protective film was produced by laminating with a roll-to-roll so that the polarization axis and the longitudinal direction of the cellulose acylate film were orthogonal to each other.

<Rubbing treatment>
The surface of the polarizing film was rubbed in the direction perpendicular to the polarization axis.

<Preparation of first optically anisotropic layer>
A first optically anisotropic layer was produced in the same manner as in the layer configuration a.

<Preparation of second optically anisotropic layer>
A second optically anisotropic layer was produced in the same manner as in the layer configuration a.

<Production of liquid crystal display device>
A liquid crystal display device was obtained in the same manner as in the layer configuration a.

(3) Production of a liquid crystal display device having a layer structure c (a liquid crystal display device having a polarizing plate in FIG. 3)
<Production of polarizing film with single-sided protective film>
It carried out similarly to the layer structure b, and produced the polarizing film with a single-sided protective film.

<Preparation of alignment film>
100 parts by mass of a compound represented by the following general formula polyvinyl alcohol (polyvinyl alcohol 1) and 5 parts by mass of a compound represented by the following T1 on the surface of the polarizing film with a single-side protective film, water: methanol = 75: 25 (mass ratio ) Was dissolved in a 4.0 mass% solution to prepare a composition for preparing a polyvinyl alcohol layer. Thereafter, this solution was applied with a wire bar coater # 8 and dried at 60 ° C. for 0.5 minutes. The film thickness of the obtained polyvinyl alcohol layer was 0.25 μm.
Polyvinyl alcohol 1 is a = 96, b = 2, and c = 2 in the polyvinyl alcohol.

  While transporting the obtained polyvinyl alcohol layer, the surface of the polyvinyl alcohol layer was rubbed in a direction perpendicular to the longitudinal direction of the film (ZRF25) to prepare a polyvinyl alcohol alignment film.

<Preparation of first optically anisotropic layer>
A first optically anisotropic layer was produced in the same manner as in the layer configuration a.

<Preparation of second optically anisotropic layer>
A second optically anisotropic layer was produced in the same manner as in the layer configuration a.

<Production of liquid crystal display device>
A liquid crystal display device was obtained in the same manner as in the layer configuration a.

(4) Production of a liquid crystal display device having a layer configuration d (the liquid crystal display device of FIG. 4)
<Preparation of rear side polarizing plate>
<< Preparation of polarizing plate protective film >>
A cellulose acylate film A was produced in the same manner as in the layer configuration (b).

<< Saponification of cellulose acylate film >>
The prepared cellulose acylate film A was immersed in a 4.5 mol / L sodium hydroxide aqueous solution (saponified solution) adjusted to 37 ° C. for 1 minute, then washed with water, and then 0.05 mol / L sulfuric acid. After being immersed in the aqueous solution for 30 seconds, it was passed through a water-washing bath. Then, draining with an air knife was repeated three times, and after dropping water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film.

<< Preparation of polarizing film >>
According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls, and a polarizing film having a width of 1330 mm and a thickness of 15 μm was prepared by stretching in the longitudinal direction.

<< Lamination >>
Using the polarizing film obtained above and the saponified film, the polarizing axis and the longitudinal direction of the cellulose acylate film using a 3% aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., polyvinyl alcohol-117H) as an adhesive. A polarizing film with a single-sided protective film was produced by laminating with a roll-to-roll so that and were orthogonal to each other.

<< Formation of alignment film >>
A polyvinyl alcohol layer was formed on the side of the polarizing film where the protective film was not pasted in the same manner as in the layer configuration a. The surface of the polyvinyl alcohol layer was continuously rubbed in the film transport direction.
<< Formation of optically anisotropic layer >>
The following coating solution for optically anisotropic layer was applied onto the rubbing surface using a bar coater. Next, the film surface is aged at 60 ° C. for 60 seconds, and irradiated with ultraviolet rays using an air-cooled metal halide lamp (produced by Eye Graphics Co., Ltd.) of 20 mW / cm ^{2 in} the air to fix the orientation state. Thus, an optically anisotropic layer was produced. In the produced optically anisotropic layer, the rod-like liquid crystal compound was horizontally aligned with the slow axis direction parallel to the rubbing direction. At this time, the thickness of the optically anisotropic layer was 1.0 μm. Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the light incident angle dependency of Re and the tilt angle of the optical axis were measured. Re was 60 nm and Rth was 550 nm. The tilt angle of the optical axis was 30 ° and 2 °.

────────────────────────────────────
Composition of coating solution for optically anisotropic layer ────────────────────────────────────
Rod-shaped liquid crystal compound B01 90 parts by weight Rod-shaped liquid crystal compound B02 10 parts by weight Photopolymerization initiator 3.0 parts by weight (Irgacure 907, manufactured by Ciba Specialty Chemicals)
Sensitizer (Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.0 part by mass The following fluorine-containing compound 0.5 part by weight methyl ethyl ketone 400 parts by weight ──────────────── ────────────────────

Fluorine-containing compounds

<Production of liquid crystal display device>
A liquid crystal display device was obtained in the same manner as in the layer configuration c except that the polarizing plate on the rear side was changed to the polarizing plate prepared above.

<Evaluation>
For the measurement of display performance, a commercially available liquid crystal viewing angle and chromaticity characteristic measuring device Ezcom (manufactured by ELDIM) was used, and a commercially available liquid crystal display device iPad (manufactured by Apple) was used for the backlight.

<< Measurement of degree of depolarization >>
The optical system of the iPad light source, polarizing film, retardation film, analyzer and light receiver (SR-UL1R manufactured by Topcon) was constructed, and the absorption axis of the polarizing film and the slow axis of the retardation film were arranged orthogonally. In the measurement of the degree of depolarization at the front, a polarizing film, a retardation film, an analyzer, and a light receiver were arranged in the normal direction of the light source, and the analyzer was rotated to measure the minimum luminance Lmin and the maximum luminance Lmax. Further, in a blank state where no retardation film was placed, the analyzer was rotated to measure the minimum luminance L ₀ min and the maximum luminance L ₀ max. The degree of depolarization was calculated by the following formula.
Depolarization level = Lmin / Lmax-L ₀ min / L ₀ max
Lmin is the maximum luminance L ₀ min cross Nicol minimum luminance Lmax is disposed between two polarizing plates parallel Nicols above retardation film of the retardation film disposed between two polarizing plates of the crossed nicols The minimum luminance L ₀ max of the two polarizing plates in the state is the maximum luminance of the two polarizing plates in the parallel Nicol state In measuring the degree of depolarization in the oblique direction, a polarizing film and a retardation film are arranged in the normal direction of the light source Then, an analyzer and a light receiver were arranged on a line inclined 50 degrees in the absorption axis direction of the polarizing film, and the analyzer was rotated to measure the minimum luminance and the maximum luminance. The degree of depolarization in the oblique direction was calculated using the same calculation formula as that for the front.

<Measurement of order parameters>
A dichroic dye was added to the composition containing the liquid crystal compound at a ratio of 1% by mass with respect to the liquid crystal compound.
In the same manner as described above, a polyvinyl alcohol layer was prepared, and the surface in the direction perpendicular to the longitudinal direction of the polyvinyl alcohol layer was rubbed to prepare a polyvinyl alcohol alignment film. The composition to which the dichroic dye was added was laminated on the surface of the obtained alignment film by a spin casting method (2500 rpm). The resulting layer was dried at the temperatures listed in the table. About the obtained film, the following measurements were implemented with the spectral absorption measuring device.
The spectrum (absorbance) when the alignment direction of the liquid crystal compound of the obtained film was made vertical and horizontal was measured. Separately, the polarization absorption spectrum (absorbance) of quartz glass was measured. A value obtained by subtracting the vertical polarization absorption spectrum of quartz glass from the vertical polarization absorption spectrum of the liquid crystal compound was defined as A⊥. The value obtained by subtracting the horizontal polarization absorption spectrum of quartz glass from the horizontal polarization absorption spectrum of the liquid crystal compound was defined as A _|| .
This was substituted into the equation OP = (A _|| -A⊥) / (2A⊥ + A _|| ) to calculate the order parameter. The optically anisotropic layer to which this dichroic dye was added was obtained by measuring the optical anisotropy to which this dye was added because the optically anisotropic layer prepared in the examples was almost the same as the material and manufacturing method. It was considered to have an order parameter equivalent to the order parameter.

<< Evaluation of Front Contrast (CR) >>
About each of the produced IPS type liquid crystal display devices, a backlight is installed, and using a measuring device (EZ-Contrast XL88, manufactured by ELDIM), luminance is measured during black display and white display, and a front contrast ratio is measured. (CR) was calculated and evaluated according to the following criteria. C and above are practical levels.
A: 900 ≦ CR
B: 850 ≦ CR <900
C: 800 ≦ CR <850
D: 800> CR

<<< Tint-habσ >>>
The variation of the tint angle hab when plotting the blackness change at a polar angle of 60 ° (measured at 73 points in 5 ° increments) on the a * b * plane is shown by the standard deviation σ. The larger the value, the greater the hue change, and the evaluation was made in the following three grades A to C. B and above are practical levels.
A: 50 or less B: Over 50 and 70 or less C: Over 70

<Vertical symmetry>
When plotted on the a * b * plane at a black azimuth angle of 45 ° (upper viewing angle) and −45 ° (lower viewing angle) at a polar angle of 60 °, the hue angle hab of the upper visual field habσu and the lower visual field The absolute value ratio of habσs was evaluated. In the case of habσu> habσs, in the case of σh = habσs / habσuhabσu <habσs, the closer the σh = habσu / habσs value is, the closer the hues in the upper visual field and the lower visual field are, and the following A˜ Evaluation was performed in three stages. B and above are practical levels.
A: 0.5 or more and 1.0 or less B: 0.2 or more and less than 0.5 C: 0.1 or more and less than 0.2

<Comprehensive evaluation>
The produced film was mounted on an Apple iPad and displayed in black, and the visual unevenness, color change, and black luminance were evaluated.
A: The visual impression is very good, no unevenness is seen, and it continues to look black even when the viewing angle is rotated.
B: Level at which the visual impression is good and unevenness and color change are not a concern.
C: A level that does not cause a problem in the product, although the visual impression is normal and the unevenness and color change are worrisome.
D: Level that causes noticeable unevenness and color change and is problematic as a product

In Examples 1 to 12, in the first optical anisotropic layer, the liquid crystal compound is fixed in a homogeneous orientation state and in a smectic phase state, and in the second optical anisotropic layer, in a homeotropic alignment state. It was fixed in a nematic phase. These were confirmed from the fact that the homeotropic layer continued to be extinguished even when the sample was rotated in a crossed Nicol environment of a polarizing microscope, and that Re≈0 and Rth had negative birefringence in the optical measurement.
In Example 11, the same amount of the following fluorine-based compound was changed without compounding the vertical alignment agents S1 and S2, and in Example 12, the first optical difference was prepared without compounding the vertical alignment agents S1 and S2. In the isotropic layer, the same amount of a compound having a hydroxyl group in the lateral direction was blended.

  In the above table, “OP” indicates an order parameter. The unit of film thickness is μm. Re and Rth indicate in-plane retardation and retardation in the thickness direction at a wavelength of 550 nm, respectively. Nz represents (nx−nz) / (nx−ny), nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents nx And the refractive index in the direction orthogonal to ny. ΔRe indicates “forward” when chromatic dispersion (Re (450) / Re (650) ≧ 1), and “reverse” indicates reverse chromatic dispersion (Re (450) / Re (650) <1).

Here, the order parameter of the first optical anisotropic layer of Comparative Example 1 was 0.72. As is clear from the above table, even when the first optical anisotropic layer and the second optical anisotropic layer are laminated as in Comparative Example 1, the order parameter of the first optical anisotropic layer is 0. When it was as small as .72, it was found that the front contrast was inferior.
When the first optical anisotropic layer and the second optical anisotropic layer are not adjacent as in Comparative Example 2, the order parameter of the first optical anisotropic layer is 0 as in Comparative Example 3. When the thickness is less than .75, as in Comparative Example 4, when the thickness of the first optical anisotropic layer exceeds 3.1 μm, the order parameter of the second optical anisotropic layer as in Comparative Example 5 is When it is less than 0.60, as in Comparative Example 6, when the film thickness of the second optical anisotropic layer is less than 0.3 μm, the film of the second optical anisotropic layer as in Comparative Example 7 It was found that when the thickness was larger than 3.0 μm, the front contrast was inferior in all cases.
On the other hand, in Examples 1 to 10, all achieved high front contrast, excellent color, and vertical symmetry. Further, it was found that higher front contrast was achieved by allowing the first optically anisotropic layer to have reverse wavelength dispersion as in Examples 7, 10, and 12. Further, as shown in Examples 9, 10 and 12, by using a polarizing plate having an optically anisotropic layer in which a liquid crystal compound is tilted and oriented as a rear polarizing plate, the color tone and vertical symmetry are further improved. The effect was obtained.

<Production of Cellulose Acylate Film (F-1)>
<< Preparation of Core Layer Cellulose Acylate Dope A >>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.
-------------------------------------------------- -----------------
Cellulose acetate having an acetyl substitution degree of 2.88 100 parts by mass Ester oligomer 2 13 parts by mass Citric acid fatty acid monoglyceride (Poem K-37V, manufactured by Riken Vitamin Co., Ltd.) 2 parts by mass Methylene chloride 430 parts by mass Methanol 64 parts by mass
-------------------------------------------------- -----------------
Ester oligomer 2

<< Preparation of outer layer cellulose acylate dope A >>
10 parts by mass of the following matting agent solution was added to 90 parts by mass of the core layer cellulose acylate dope to prepare an outer layer cellulose acetate solution.
-------------------------------------------------- -----------------
Silica particles having an average particle size of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride 76 parts by mass Methanol 11 parts by mass Core layer Cellulose acylate dope A 1 part by mass
-------------------------------------------------- -----------------

<< Film Formation of F-1 >>
The polymer solution is filtered through a filter paper having an average pore diameter of 34 μm and a sintered metal filter having an average pore diameter of 10 μm, and then the core layer cellulose acylate dope A and the outer layer cellulose acylate dope A on both sides thereof are simultaneously cast from the casting port. Cast on a 20 ° C. drum. The film was peeled off at a solvent content of about 20% by mass, both ends in the width direction of the film were fixed with tenter clips, and dried while being stretched 1.1 times in the lateral direction. Then, it dried further by conveying between the rolls of a heat processing apparatus, produced the 25-micrometer-thick retardation film, and made this into the cellulose acylate film F-1.

<Production of Cellulose Acylate Films F-2 and F-3>
<< Preparation of core layer cellulose acylate dope B >>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.
-------------------------------------------------- ----------------
Cellulose acetate with an acetyl substitution degree of 2.88 100 parts by mass Ester oligomer 3 15 parts by mass Methylene chloride 333 parts by mass Methanol 63 parts by mass Butanol 3 parts by mass
-------------------------------------------------- ----------------

<< Preparation of core layer cellulose acylate dope C >>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.
-------------------------------------------------- ----------------
Cellulose acetate with an acetyl substitution degree of 2.88 100 parts by mass ester oligomer 3 15 parts by mass Citric acid fatty acid monoglyceride (Poem K-37V, manufactured by Riken Vitamin Co., Ltd.) 3 parts by mass Methylene chloride 331 parts by mass Methanol 62 parts by mass Butanol 3 parts by mass Part
-------------------------------------------------- -----------------
Ester oligomer 3

<< Preparation of outer layer cellulose acylate dope B >>
1.3 parts by mass of the following matting agent solution was added to 100 parts by mass of the core layer cellulose acylate dope B to prepare an outer layer cellulose acetate solution.
-------------------------------------------------- -------------------
Silica particles having an average particle size of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 10 parts by mass Methylene chloride 73 parts by mass Methanol 4 parts by mass Butanol 1 part by mass Core layer Cellulose acylate dope B 10 parts by mass
-------------------------------------------------- -------------------

<< Film formation of F-2 and F-3 >>
The polymer solution is filtered 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, and then the core layer cellulose acylate dope B and the outer layer cellulose acylate dope B on both sides thereof are simultaneously cast from the casting port. Cast on a drum cooled to -5 ° C. The film is peeled off in a state where the solvent content is about 70% by mass, and both ends in the width direction of the film are fixed with a pin tenter (a pin tenter described in FIG. And kept dry. Then, it dried further by conveying between the rolls of a heat processing apparatus, produced the 40-micrometer-thick retardation film, and made this into the cellulose acylate film F-2. Further, a film having a thickness of 40 μm was prepared in the same manner by using a combination of the core layer cellulose acylate dope C and the outer layer cellulose acylate dope B on both sides thereof, and this was prepared as a cellulose acylate film F-3. did.

  In Example 1, even if the cellulose acylate films F-1, F-2, and F-3 produced instead of ZRF25, which is a support for the retardation film, were used, the display performance and the evaluation point of the comprehensive evaluation were changed. All achieved high front contrast, excellent color, and vertical symmetry.

  Moreover, even if it uses the cellulose acylate film F-1, F-2, and F-3 produced instead of ZRF25 used for a rear side polarizing plate in Example 1, the evaluation point of display performance and comprehensive evaluation changes. All achieved high front contrast, excellent color, and vertical symmetry.

1: Polarizing film 2: Polarizing film protective film 3: Retardation film 4: First optical anisotropic layer 5: Second optical anisotropic layer 6: Retardation film support 7: Alignment film 8: Hard coat layer 9: Liquid crystal cell 10: Rear side polarizing plate 11: Rear side polarizing film 12: Rear side polarizing film protective film 13: Alignment film 14: Optical anisotropic layer

Claims (17)

A first optically anisotropic layer and a second optically anisotropic layer on the surface of the first optically anisotropic layer,
The first optically anisotropic layer is formed by fixing a liquid crystal compound in a homogeneous alignment state, the order parameter is 0.75 to 0.95, and the thickness of the layer is 0.3 to 3.0 μm. And
The second optically anisotropic layer comprises a liquid crystal compound fixed in a homeotropic alignment state, an order parameter of 0.60 to 0.95, and a layer thickness of 0.3 to 3. 0 μm, retardation film; provided that the order parameter OP is
OP = (A _|| -A⊥) / (2A⊥ + A _|| )
“A _|| ” means absorbance for light polarized parallel to the alignment direction of the liquid crystal compound “A⊥” means absorbance for light polarized perpendicular to the alignment direction of the liquid crystal compound. The retardation film according to claim 1, wherein the first optically anisotropic layer is a layer formed by fixing a liquid crystal compound in a smectic phase state. The retardation film according to claim 1, wherein the second optically anisotropic layer is a layer formed by fixing a liquid crystal compound in a nematic phase. The retardation film according to claim 1, wherein the first optically anisotropic layer satisfies the following formulas (1) and (2);
Formula (1)
100 nm ≦ Re (550) ≦ 200 nm
Formula (2)
0.8 ≦ Nz ≦ 1.2
In the formula (1), Re (550) indicates in-plane retardation at a wavelength of 550 nm.
In Formula (2), Nz represents (nx−nz) / (nx−ny), nx represents the refractive index in the slow axis direction in the plane, and ny represents the refraction in the direction perpendicular to nx in the plane. Nz represents the refractive index in the direction orthogonal to nx and ny. The retardation film according to claim 1, wherein the first optical anisotropic layer satisfies the following formula (3);
Formula (3)
Re (450) / Re (650) <1
In formula (3), Re (450) and Re (650) indicate in-plane retardation at wavelengths of 450 nm and 650 nm, respectively. The retardation film according to claim 1, wherein the first optically anisotropic layer contains a leveling agent. The retardation film according to claim 1, wherein the second optically anisotropic layer contains a vertical alignment agent. The retardation film according to claim 1, wherein the retardation film has a thickness of 0.6 to 6 μm. The retardation film according to claim 1, wherein each of the first optical anisotropic layer and the second optical anisotropic layer contains a rod-like liquid crystal compound. The retardation film according to claim 1, comprising an alignment film, the first optical anisotropic layer, and the second optical anisotropic layer in this order on a support. The polarizing plate which has a polarizing film and the phase difference film of any one of Claims 1-10. The polarizing plate according to claim 11, wherein a first optical anisotropic layer is provided on a surface of the polarizing film. A liquid crystal display device comprising the retardation film according to any one of claims 1 to 10 or the polarizing plate according to claim 11 or 12. The liquid crystal display device according to claim 13, which is for IPS mode. The liquid crystal display device according to claim 13 or 14, comprising the polarizing plate according to claim 11 or 12 on a front side of the liquid crystal display device. The in-plane retardation Re (550) at a wavelength of 550 nm is 30 to 120 nm between the rear polarizing film and the liquid crystal cell of the liquid crystal display device, and the thickness direction retardation Rth (550) at a wavelength of 550 nm is 20. The liquid crystal display device according to claim 15, which has an optical film of ˜100 nm. The liquid crystal display device according to claim 16, wherein the optical film on the rear side of the liquid crystal display device has an optically anisotropic layer in which a liquid crystal compound is tilt-oriented.