JP6063822B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device.

In the recent flat panel display market, higher definition of pixels has been promoted for the purpose of improving image quality. In particular, high-definition TVs called so-called 4K2K are beginning to be sold for TV applications, although they are remarkable for small sizes such as tablet PCs and smartphones.
As the liquid crystal mode, TN mode, IPS mode, VA mode, etc. are known. However, VA mode occupies most in TV applications, and currently, the pixel division method called 8-domain (8D) is the mainstream in VA mode. .
However, since the pixel structure is complicated, it is not suitable for high definition, and there is a drawback that the use efficiency of backlight light decreases when the definition is increased. In view of this, it is conceivable to use a pixel division method in which the number of domains (4 domains (4D) and 2 domains (2D)) is reduced in order not to reduce the backlight light utilization efficiency with a simple structure.
However, if the number of domains is lowered, the problem of “overexposure” that the image becomes whitish when observed from the lateral direction occurs. This is because the “gradation characteristics” (characteristics when the horizontal axis is GRAY LEVEL and the vertical axis is transmittance), which is known by a name such as “γ curve”, is different from the front. On the other hand, improvement with a cell or a film has been studied (Patent Document 1, Non-Patent Document 1, and Non-Patent Document 2).

JP 2005-62724 A

SID 06 Digest 69.3 p.1946-1949 Optics Letters Vol. 38, No. 5 p.799-801

Here, Patent Document 1 improves the overexposure with an optical film made of a disk-like polymer in which the arrangement is different in the thickness direction. However, there is a problem that the viewing angle contrast is extremely deteriorated. Non-Patent Document 1 improves overexposure with a liquid crystal cell. However, there is a problem that the liquid crystal cell is limited when the overexposure is improved by the liquid crystal cell. On the other hand, Non-Patent Document 2 uses a retardation film to improve overexposure. However, there is a problem that it tends to be tinted.
The present invention is intended to solve such problems, and provides a liquid crystal display device that suppresses overexposure and tints in a VA mode liquid crystal display device of four domains or less. The purpose is to do.

As a result of intensive studies by the inventor under the above problems, the above problems have been solved by the following means <1>, preferably <2> to <6>.
<1> having at least a first polarizing film, a first retardation layer, a liquid crystal layer, a second retardation layer, and a second polarizing film in this order,
The liquid crystal layer is in a vertical alignment mode (VA mode) when no voltage is applied with 4 domains or less,
The in-plane retardation Re (550) at a wavelength of 550 nm of the first retardation layer is 40 to 110 nm, and the retardation Rth (550) in the thickness direction at a wavelength of 550 nm of the first retardation layer is 400 to 500 nm. Yes,
Re (550) of the second retardation layer is 40 to 110 nm, Rth (550) of the second retardation layer is -200 to -100 nm,
The angle between the slow axis of the first retardation layer and the absorption axis of the first polarizing film is 45 °, and the slow axis of the first retardation layer and the surface of the liquid crystal layer when a voltage is applied It is orthogonal to the inner slow axis,
The angle formed by the slow axis of the second retardation layer and the absorption axis of the second polarizing film is 45 °, and the slow axis of the second retardation layer and the retardation of the first retardation layer are It is orthogonal to the phase axis,
A liquid crystal display device, wherein the liquid crystal layer has a retardation (Δnd) of 250 to 450 nm.
<2> The first retardation film and the first retardation layer, or the third retardation layer between the second polarization film and the second retardation layer, and the third retardation layer. Liquid crystal display device.
<3> The in-plane retardation Re (550) of the third retardation layer at a wavelength of 550 nm is 245 to 305 nm, and the retardation Rth (550) in the thickness direction at a wavelength of 550 nm is −30 to 30 nm. The liquid crystal display device according to 2>.
<4> An optically biaxial film in which the third retardation layer has Re (550) of 70 to 140 nm and Rth (550) of 40 to 110 nm, and Re (550) is 10 nm or less. The liquid crystal display device according to <2>, wherein Rth (550) is a laminated film with a film having a thickness of −180 to −90 nm.
<5> The liquid crystal display device according to any one of <1> to <4>, wherein the liquid crystal layer includes two domains.
<6> The first retardation layer and the second retardation layer are pattern retardation layers, and the slow axis of the first retardation layer and the slow axis of the second retardation layer are orthogonal to each other. The liquid crystal display device according to any one of <1> to <5>.

  In a VA mode liquid crystal display device of 4 domains or less, it has become possible to provide a liquid crystal display device in which occurrence of coloring and overexposure are suppressed.

It is the schematic which shows an example of a structure of the liquid crystal display device of this invention. It is the schematic which shows an example of a structure of the liquid crystal display device of a prior art. It is the schematic which shows another example of a structure of the liquid crystal display device of this invention.

  Hereinafter, the present invention will be described in detail. In addition, the numerical value range represented using "to" in this specification means the range which includes the numerical value described before and behind as a lower limit and an upper limit.

In this specification, the “slow axis” means a direction in which the refractive index is maximized.
In the present specification, unless otherwise specified, for example, “45 °”, “parallel”, “vertical”, or “orthogonal” means that the angle is within a range of strictly less than ± 5 degrees. That is, it means approximately 45 °, approximately parallel, and approximately vertical. The error from the exact angle is preferably less than ± 4 degrees, and more preferably less than ± 3 degrees. As for the angle, “+” means the counterclockwise direction, and “−” means the clockwise direction.
Regarding the angle of the slow axis and the absorption axis, the absorption axis of the first polarizing film is 0 °, and when viewed from the viewing side, the counterclockwise direction is the positive direction.

  The liquid crystal display device of the present invention has at least a first polarizing film, a first retardation layer, a liquid crystal layer, a second retardation layer, and a second polarizing film in this order, and the liquid crystal layer has 4 domains or less. In the vertical alignment mode (VA mode) when no voltage is applied, the in-plane retardation Re (550) at a wavelength of 550 nm of the first retardation layer is 40 to 110 nm, and the wavelength of the first retardation layer is 550 nm. Retardation Rth (550) in the thickness direction is 400 to 500 nm, Re (550) of the second retardation layer is 40 to 110 nm, and Rth (550) of the third retardation layer is −200 to −100 nm, the angle formed by the slow axis of the first retardation layer and the absorption axis of the first polarizing film is 45 °, and the slow axis of the first retardation layer and voltage application Is perpendicular to the in-plane slow axis of the liquid crystal layer The angle formed by the slow axis of the second retardation layer and the absorption axis of the second polarizing film is 45 °, and the slow axis of the second retardation layer and the retardation of the first retardation layer are It is perpendicular to the phase axis, and the retardation (Δnd) of the liquid crystal layer is 250 to 450 nm. By setting it as such a structure, the liquid crystal display device with which overexposure and coloring were suppressed is obtained. Here, “colored” means that a color is formed when a film with Re exceeding λ / 2 is inserted between two polarizing films. Furthermore, in the present invention, the viewing angle contrast and the front contrast can be improved. In addition, the utilization efficiency of the backlight can be improved.

  Various methods for improving overexposure have been studied. Non-Patent Document 1 (SID 06 Digest) discloses that an average image is output by changing the voltage application method between the A pixel (4 domains) and the B pixel (4 domains). ing. That is, in this document, the overexposure is improved by the cell itself.

On the other hand, Non-Patent Document 2 (Optics Letters Vol. 38, No. 5) uses a retardation film to improve overexposure. However, as a result of examination by the present inventors, it has been found that coloring occurs in this document. This point will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an example of the configuration of the liquid crystal display device of the present invention. In order from the upper side, a first polarizing film 1, a first retardation layer 2, a liquid crystal layer 4, and a second retardation layer are illustrated. 5 and the second polarizing film 6 are laminated in this order. On the other hand, Non-Patent Document 2 (Optics Letters Vol. 38, No. 5) has a configuration shown in FIG. Compared with FIG. 1, in order from the top, the first polarizing film 11, the first retardation layer 12, the third retardation layer 13, the liquid crystal layer 14, the second retardation layer 15, and the fourth phase. The phase difference layer 16 and the second polarizing film 17 are configured. Here, examples of the retardation value at a wavelength of 550 nm of the respective retardation layers having the configurations shown in FIGS. 1 and 2 include the following values (unit: nm).

  As described above, Re of the first retardation layer 12 in FIG. 2 is 320 nm, and Re greatly exceeds λ / 2, so that coloring occurs.

The difference between FIG. 1 and FIG. 2 will be described more specifically. In the configuration of FIG. 2, the + A plate and the -A plate are combined to perform the viewing angle compensation in black and the whiteout compensation in the halftone at the same time. (ne axis) uses the same property that the sign of retardation is opposite. However, since the optical axes of both the + A plate and the -A plate are fixed, a large Re (320 nm in the case of FIG. 2) is necessary to obtain halftone overexposure compensation. Further, in the configuration of FIG. 2, a -C plate (in this case, Rth = 300 nm) is required to compensate the liquid crystal layer.
On the other hand, in the present invention (FIG. 1), the first and second retardation layers are utilized by changing the respective axes by changing the ratio of Re and Rth of the first and second retardation layers. An attempt was made to adjust the optical axis and retardation in the oblique direction to obtain overexposure compensation, and to compensate the liquid crystal layer simultaneously. As a result, it was found that Re = 75 nm and Rth = 450 nm of the first retardation layer, and that the second retardation layer Re = 75 nm and Rth = −150 nm. Under these conditions, the absolute value of Re is as small as 75 nm and is much lower than λ / 2, so that coloring can be greatly reduced.

The configuration of the present invention will be specifically described below.
The liquid crystal display device of the present invention includes a first polarizing film, a first retardation layer, a liquid crystal layer, a second retardation layer, and a second polarizing film in this order, and the liquid crystal layer has a voltage of 4 domains or less. Vertical alignment mode (VA mode) when no voltage is applied, in-plane retardation Re (550) at a wavelength of 550 nm of the first retardation layer is 40 to 110 nm, and thickness of the first retardation layer at a wavelength of 550 nm Direction retardation Rth (550) is 400-500 nm,
Re (550) of the second retardation layer is 40 to 110 nm, Rth (550) of the second retardation layer is −200 to −100 nm, and the slow axis of the first retardation layer, The angle formed by the absorption axis of the first polarizing film is 45 °, and the slow axis of the first retardation layer is orthogonal to the in-plane slow axis of the liquid crystal layer when a voltage is applied. The angle formed between the slow axis of the second retardation layer and the absorption axis of the second polarizing film is 45 °, and the slow axis of the second retardation layer and the slow phase of the first retardation layer The liquid crystal layer has a retardation (Δnd) of 250 to 450 nm perpendicular to the axis. The upper side (first polarizing film side) in FIG. 1 may be the viewing side, and the lower side (second polarizing film side) in FIG. 1 may be the viewing side. Each of the first retardation layer, the second retardation layer, and the other retardation layer may be composed of one layer, or may be composed of two or more layers, and at least one retardation The layer may have an optically anisotropic layer containing a liquid crystal compound.

  The absorption axes of the first polarizing film and the second polarizing film are orthogonal to each other. A known polarizing film can be used as the polarizing film. For example, the description of paragraph number 0090 of JP2012-150377A can be referred to, and the contents thereof are incorporated in the present specification.

The first retardation layer is optically biaxial and is a film disposed between the first polarizing film and the second retardation layer, and the first retardation layer has a wavelength of 550 nm. The in-plane retardation Re (550) is 40 to 110 nm, and the retardation Rth (550) in the thickness direction at a wavelength of 550 nm of the first retardation layer is 400 to 500 nm. The first retardation layer cooperates with the second retardation layer to suppress the occurrence of overexposure. Further, since Re (550) is small, the front contrast can be improved.
The Re (550) of the first retardation layer is preferably 50 to 100 nm, and more preferably 60 to 90 nm. Rth (550) of the first retardation layer is preferably 420 to 480 nm.

  The method for producing the first retardation layer is not particularly defined, and is produced using a known technique so as to satisfy the above retardation. As an example, it is manufactured by a method of forming an optically anisotropic layer containing a liquid crystal compound (particularly a method of forming a rod-like liquid crystal compound by horizontally aligning), a method of blending a retardation adjusting agent, and / or a method of stretching. it can. Regarding these details, Japanese Patent Application Laid-Open No. 2009-235374 can be referred to for a single layer structure, and Japanese Patent Application Laid-Open No. 2012-8548 can be referred to for a layered structure, and these contents are incorporated in the present specification.

The first retardation layer is preferably a method of forming an optically anisotropic layer containing a liquid crystal compound from the viewpoint of reducing the thickness of the liquid crystal display device. By forming the first retardation layer using an optically anisotropic layer containing a liquid crystal compound, the thickness of the first retardation layer can be about 1.0 μm to 3.0 μm.
When the liquid crystal layer has four domains, the first retardation layer is a pattern retardation layer. When the liquid crystal layer has four domains, the two domains located in the diagonal direction have an in-plane slow axis of 45 °, and the remaining two domains have an in-plane slow axis of 135 °. The layer becomes a pattern retardation layer. In this case, the angle formed by the slow axis of the pattern retardation layer adjacent to a certain pattern retardation layer differs by 90 degrees. As a method for forming the pattern retardation layer, descriptions in JP2013-011800A, JP2013-068924A, JP2012-517024A, and the like can be referred to, and the contents thereof are incorporated in the present specification. .

The slow axis of the first retardation layer (for example, the arrow in the first retardation layer 2 of FIGS. 1 and 3) is the absorption axis of the first polarizing film (for example, the first polarization of FIG. 1). The angle formed with the arrow in the film 1 is 45 °, and the slow axis of the first retardation layer is orthogonal to the in-plane slow axis of the liquid crystal layer when a voltage is applied.
In addition, the first retardation layer may have an in-cell structure. By adopting the in-cell structure, overexposure tends to be suppressed. When the first retardation layer has an in-cell structure, the second retardation layer also preferably has an in-cell structure.

  The liquid crystal layer in the present invention is a vertical alignment mode (VA mode) when no voltage is applied and has 4 domains or less, and may be 4 domains or 2 domains, and is particularly preferably used for 4 domains.

  The VA mode liquid crystal cell is described in KH Kim, KH Lee, SB Park, JK Song, SN Kim, and JH Souk, Asia Display '98, p. 383, 1998, in order to determine the direction of the slow axis when electrification is applied. Referring to the above, if the transparent electrode of the cell substrate is provided with a slit, the direction in which the liquid crystal molecules of the liquid crystal cell fall when the voltage is applied can be determined. For example, when creating a two-domain cell with in-plane slow axes of 45 ° and 225 ° when electrification is applied, the slit direction of the transparent electrodes on the upper and lower substrates is set to 135 °, which is perpendicular to 45 ° and 225 °. When assembling the cells so that the slit positions of the upper and lower substrates are staggered, the direction in which the liquid crystal molecules fall due to the distortion of the electric field at the edge of the slit of the transparent electrode can be controlled. Get the inner slow axis (called Patterned Vertical Alignment). In this case, the in-plane slow axis coincides with 45 ° and 225 °, but the polar angle direction in which the liquid crystal molecules fall is different between 45 ° and 225 °. Similarly, when creating a two-domain cell having in-plane slow axes of 135 ° and 315 ° when electrification is applied, the slit direction of the transparent electrodes of the upper and lower substrates is in the direction of 45 ° which is perpendicular to 135 ° and 315 °. To. When creating 4-domain cells with in-plane slow axes of 45 °, 225 °, 135 °, and 315 ° when electrification is applied, the slit directions of the transparent electrodes on the upper and lower substrates are mixed in the same plane at 135 ° and 45 °. Can be obtained.

The retardation of the VA mode liquid crystal layer (that is, the product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn) is preferably 250 to 450 nm, more preferably 280 to 320 nm. Those in a range other than those can be preferably employed.
In the examples of the present invention described later, the retardation of the liquid crystal layer is represented by Rth, which has a relationship of Rth = −Δn · d.
This is because when the voltage is not applied to the liquid crystal cell, that is, in the black display, the liquid crystal in the liquid crystal cell is substantially perpendicular to the substrate in the direction of maximum refractive index. This is because it is considered.
Details of the VA mode liquid crystal cell and the liquid crystal layer can be referred to the description in JP 2013-07749 A, particularly the description of paragraph numbers 0185 to 0187, the contents of which are incorporated herein.

The second retardation layer is optically biaxial and is a film disposed between the liquid crystal layer and the second polarizing film, and Re (550) of the second retardation layer is 40 to 40. 110 nm, and Rth (550) of the second retardation layer is −200 to −100 nm. The second retardation layer cooperates with the first retardation layer to suppress occurrence of overexposure.
The Re (550) of the second retardation layer is preferably 40 to 100 nm, and more preferably 50 to 90 nm. Rth (550) of the first retardation layer is preferably −290 to −200 nm.

As described above, the first retardation layer and the second retardation layer cooperate to suppress overexposure. Therefore, in the liquid crystal display device of the present invention, the overexposure is more effectively suppressed by reducing the difference between Re (550) of the first retardation layer and Re (550) of the second retardation layer. The The difference between the absolute value of Re (550) of the first retardation layer and the absolute value of Rth of the second retardation layer is 10 nm or less, preferably 5 nm or less, and substantially 0 nm. Is more preferable.
Further, the difference between the absolute value of Rth (550) of the first retardation layer and the absolute value of Rth of the second retardation layer is 10 nm or less, preferably 5 nm or less, substantially 0 nm. More preferably. By setting it as such a structure, front contrast can be improved more effectively.

The method for producing the second retardation layer is not particularly defined, and is produced using a known technique so as to satisfy the above retardation. As an example, it is manufactured by a method of forming an optically anisotropic layer containing a liquid crystal compound (particularly a method of forming a rod-like liquid crystal compound by horizontally aligning), a method of blending a retardation adjusting agent, and / or a method of stretching. it can. Regarding these details, Japanese Patent Application Laid-Open No. 2009-235374 can be referred to for a single layer structure, and Japanese Patent Application Laid-Open No. 2012-8548 can be referred to for a layered structure, and these contents are incorporated in the present specification.
The second retardation layer is preferably a method of forming an optically anisotropic layer containing a liquid crystal compound from the viewpoint of thinning the liquid crystal display device. By forming the second retardation layer using an optically anisotropic layer containing a liquid crystal compound, the thickness of the second retardation layer can be about 1.0 μm to 3.0 μm.

The slow axis of the second retardation layer (for example, the arrow in the second retardation layer 5 of FIGS. 1 and 3) is the absorption axis of the second polarizing film (for example, the first polarization of FIG. 1). The angle formed by the arrow in the film 6 is 45 °, and the slow axis of the first retardation layer and the slow axis of the second retardation layer are orthogonal to each other.
In addition, the second retardation layer may have an in-cell structure. By adopting the in-cell structure, overexposure tends to be suppressed. When the second retardation layer has an in-cell structure, the first retardation layer also preferably has an in-cell structure.

When the liquid crystal layer has four domains, the second retardation layer is a pattern retardation layer. As a method for forming the pattern retardation layer, descriptions in JP2013-011800A, JP2013-068924A, JP2012-517024A, and the like can be referred to, and the contents thereof are incorporated in the present specification. .
When the liquid crystal layer has four domains, the pattern retardation layer may be a horizontal stripe pattern. As a liquid crystal pixel structure that can use a horizontal stripe pattern in the pattern retardation layer, a so-called MVA structure, for example, Y. Tanaka, Y. Taniguchi, T. Sasaki, A. Takeda, Y. Koibe, and K Okamoto, "A New Design to Improve Performance and Simply the manufacturing Process of High-Quality MVA TFT-LCD Panels", SID Symposium Digest, p. 206, 1999,
There are so-called PVA structures KH Kim, KH Lee, SB Park, JK Song, SN Kim, and JH Souk, Asia Display '98, p. 383, 1998. Incorporated into.

  In the liquid crystal display device of the present invention, the same effect can be obtained when the first polarizing film is set as the viewing side and when the second polarizing film is set as the viewing side unless the configuration order of the layers is changed. it can.

  In addition, the liquid crystal display device of the present invention may have other constituent layers without departing from the spirit of the present invention. For example, a third retardation layer may be provided between the first polarizing film and the first retardation layer or between the second polarizing film and the second retardation layer. That is, FIG. 3 is a schematic diagram illustrating an example of a configuration of a liquid crystal display device having a third retardation layer 3 between the first polarizing film and the first retardation layer. It is common with FIG. The slow axis of the third retardation layer (the arrow in the third retardation layer 3 in FIG. 3) is the absorption axis of the first polarizing film (the arrow in the first polarizing film 1 in FIG. 3). It is preferable that they are orthogonal. By providing the third retardation layer 3 in this way, the polarizing film can be compensated, and the contrast (viewing angle CR) from the oblique direction can be further improved.

The third retardation layer may be a single layer or a stacked layer.
In the case of a single layer, Re (550) is preferably 250 to 305 nm, more preferably 260 to 290 nm. Rth (550) is preferably -30 to 30 nm, and more preferably -15 to 15 nm. However, in the case of lamination, it is preferable in that wavelength dispersion is easy to control and there is no black tint in an oblique direction.
The third retardation layer is more preferably laminated to reduce the black tint. Various combinations are considered for the form of the laminated structure. Among them, a laminated structure of a biaxial film and a so-called positive C-plate is preferable. 70-140 nm is preferable and Re (550) of a biaxial film has more preferable 90-120 nm. Rth (550) of the biaxial film is preferably 40 to 110 nm, and more preferably 90 to 110 nm. The positive C-plate in the present invention has Re (550) of 10 nm or less, and Rth (550) is preferably -180 to -90 nm, more preferably -180 to -130 nm.
For these, a retardation film used for compensation of a known polarizing film can be widely used. Regarding these details, Japanese Patent Application Laid-Open No. 2009-235374 can be referred to for a single layer structure, and Japanese Patent Application Laid-Open No. 2012-8548 can be referred to for a layered structure, and these contents are incorporated in the present specification.

  In the case of a laminated configuration of a biaxial film and a positive C-plate, the in-plane slow axis of the biaxial film is perpendicular to the absorption axis direction of the first polarizing film. Since the positive C-plate does not have an in-plane slow axis, there is no restriction when stacking.

  In this specification, Re (λ) and Rth (λ) represent in-plane retardation (unit: nm) and retardation in the thickness direction (unit: nm) at wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (in the absence of the slow axis, any in-plane value) The light is incident at a wavelength of λ nm from the inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction of the rotation axis of KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed 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.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following formulas (21) and (22).

上記式中、Ｒｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値を表す。また、上記式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘおよびｎｙに直交する方向の屈折率を表す。ｄはフィルムの膜厚を表す。

In the above formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In the above formula, 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 the refractive index in the direction perpendicular to nx and ny. Represent. d represents the film thickness of the film.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no 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 (rotation axis) from −50 degrees to +50 degrees with respect to the film normal direction. The light of wavelength λ nm is incident from each inclined direction in 10 degree steps and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or WR is calculated.

In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
By inputting these assumed values of average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  In the present specification, when there is no particular measurement wavelength for Re and Rth, the measurement wavelength is 550 nm. Moreover, when there is no description about a measurement environment especially, it shall be the value measured in the environment of temperature 25 degreeC relative humidity 60% RH.

  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.

<Preparation of Cellulose Acylate Film 001>
<< Preparation of cellulose acylate >>
A cellulose acylate having a total substitution degree of 2.97 (breakdown: acetyl substitution degree: 0.45, propionyl substitution degree: 2.52) was prepared. A mixture of sulfuric acid as a catalyst (7.8 parts by mass with respect to 100 parts by mass of cellulose) and carboxylic anhydride was added to cellulose derived from pulp after cooling to -20 ° C, and acylated at 40 ° C. . At this time, the kind of acyl group and its substitution ratio were adjusted by adjusting the kind and amount of carboxylic anhydride. After acylation, aging was performed at 40 ° C. to adjust the total substitution degree.

<< Preparation of cellulose acylate solution >>
1) Cellulose acylate The prepared cellulose acylate was heated to 120 ° C. and dried to adjust the water content to 0.5% by mass or less, and then 30 parts by mass was mixed with a solvent.
2) Solvent Dichloromethane / methanol / butanol (81/15/4 parts by mass) was used as a solvent. The water content of these solvents was 0.2% by mass or less.
3) Additive In preparing all the solutions, 0.9 parts by mass of trimethylolpropane triacetate was added. In addition, silicon dioxide fine particles (particle size 20 nm, about 0.25 parts by mass) were added in preparing all the solutions.
Further, 1.2% by mass of the following UV absorber A was added to 100 parts by mass of the cellulose acylate, and 11% by mass of the following Rth reducing agent B was added to 100 parts by mass of the cellulose acylate.
Re (550) of the obtained cellulose acylate film 001 was -1 nm, and Rth (550) was -1 nm, and an optically isotropic film was obtained.

4) Swelling and dissolution The cellulose acylate was gradually added to the stainless steel dissolution tank having stirring blades and circulating cooling water around the outer periphery, while stirring and dispersing the solvent and additives. After completion of the addition, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a cellulose acylate solution.
For stirring, a dissolver type eccentric stirring shaft that stirs at a peripheral speed of 15 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² ) and an anchor blade on the central axis and a peripheral speed of 1 m / sec. A stirring shaft that stirs at a sec (shear stress of 1 × 10 ⁴ kgf / m / sec ² ) was used. Swelling was carried out with the high speed stirring shaft stopped and the peripheral speed of the stirring shaft having anchor blades set at 0.5 m / sec.

5) Filtration The cellulose acylate solution obtained above was filtered with a filter paper (# 63, manufactured by Toyo Roshi Kaisha, Ltd.) having an absolute filtration accuracy of 0.01 mm, and further a filter paper (FH025, Poll) having an absolute filtration accuracy of 2.5 μm. To obtain a cellulose acylate solution.

<< Production of Cellulose Acylate Film >>
The cellulose acylate solution was heated to 30 ° C., and cast on a mirror surface stainless steel support having a band length of 60 m set at 15 ° C. through a casting Giesser (described in JP-A-11-314233). The casting speed was 15 m / min and the coating width was 200 cm. The space temperature of the entire casting part was set to 15 ° C. Then, the cellulose acylate film that had been cast and rotated 50 cm before the cast part was peeled off from the band, and 45 ° C. dry air was blown. Next, it was dried at 110 ° C. for 5 minutes and further at 140 ° C. for 10 minutes to obtain a cellulose acylate film 001 (film thickness 81 μm). The cellulose acylate film obtained had Re of -1 nm and Rth of -1 nm.

<Production Method 1: Production of Second Retardation Layer>
According to the following method, second retardation layer films used in the liquid crystal display devices of Examples and Comparative Examples using a two-domain (2D) liquid crystal layer were produced.
<< Alkaline saponification treatment >>
The cellulose acylate film 001 was passed through a dielectric heating roll having a temperature of 60 ° C., and the film surface temperature was raised to 40 ° C., and then an alkali solution having the composition shown below was applied to one side of the film using a bar coater. The coating was carried out for 10 seconds under a steam far-infrared heater manufactured by Noritake Company Limited, which was applied at an amount of 14 ml / m ² and heated to 110 ° C. Subsequently, 3 ml / m ^{2 of} pure water was applied using the same bar coater. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then transported to a drying zone at 70 ° C. for 10 seconds and dried to prepare an alkali saponified cellulose acylate film.

Alkaline solution composition ───────────────────────────────────
Potassium hydroxide 4.7 parts by weight Water 15.8 parts by weight Isopropanol 63.7 parts by weight Surfactant SF-1: C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) ₂₀ H 1.0 part by weight Propylene glycol 14. 8 parts by mass ───────────────────────────────────

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

Modified polyvinyl alcohol

<< Formation of Optically Anisotropic Layer Containing Discotic Liquid Crystal Compound >>
The alignment film thus prepared was continuously rubbed. At this time, the longitudinal direction of the long film and the transport direction were parallel, and the rotation axis of the rubbing roller was 45 ° clockwise relative to the longitudinal direction of the film.

  A coating liquid (A) containing a discotic liquid crystal compound having the following composition was applied on the prepared alignment film using a wire bar. In order to dry the solvent of the coating solution and to mature the orientation of the discotic liquid crystal compound, it was heated with hot air at 80 ° C. for 90 seconds. Subsequently, UV irradiation was performed at 80 ° C., the orientation of the liquid crystal compound was fixed, an optically anisotropic layer was formed, and an optical film was obtained. The film thickness of the optically anisotropic layer was 2.0 μm.

Composition of coating solution (A) for optically anisotropic layer ―――――――――――――――――――――――――――――――――――
The following discotic liquid crystal compound 100 parts by mass photopolymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following pyridinium salt 1 part by mass Fluoropolymer (FP1) 0.4 parts by mass Methyl ethyl ketone 252 parts by mass ―――――――――――――――――――――――――――――――――― -

  The evaluation results of the produced optical film are shown below. The direction of the slow axis was parallel to the rotation axis of the rubbing roller. That is, the slow axis was 45 ° clockwise relative to the longitudinal direction of the support. Further, the thickness of the optically anisotropic layer was adjusted so that Re (550) and Rth (550) were values shown in the following table, and respective second retardation layer films were prepared.

<Production method 2: Production of production of first retardation layer>
According to the following method, first retardation layer films used in the liquid crystal display devices of Examples and Comparative Examples using a two-domain (2D) liquid crystal layer were produced.
The surface of the cellulose acylate film 001 produced above was saponified with an alkaline solution, and an alignment film coating solution having the following composition was applied onto the film with a wire bar coater at 20 ml / m ² . A film was formed by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, the formed film was rubbed in a 45 ° direction with respect to the longitudinal direction of the cellulose acylate film 001 to form an alignment film.

Composition of alignment film coating solution ―――――――――――――――――――――――――――――――――――
Modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight ――――――――――――――――――――――――――― ――――――――

Next, an optically anisotropic layer coating solution having the following composition was applied with a wire bar.
―――――――――――――――――――――――――――――――――――
The following rod-like liquid crystalline compound 1.8g
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g
Photopolymerization initiator (Irgacure 907, manufactured by BASF) 0.06 g
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02g
Methyl ethyl ketone 3.9g
―――――――――――――――――――――――――――――――――――

  This was heated in a constant temperature bath at 125 ° C. for 3 minutes to align the rod-like liquid crystal compound. Next, using a 120 W / cm high-pressure mercury lamp, ultraviolet rays were irradiated for 30 seconds to crosslink the rod-like liquid crystalline compound. The temperature at the time of ultraviolet curing was set to 80 ° C. to obtain an optically anisotropic layer. The thickness of the optically anisotropic layer was 2.0 μm. Then, it stood to cool to room temperature. In this way, an optical film (+ A-plate) was produced.

また、Ｒｅ（５５０）およびＲｔｈ(５５０)が下記表の値となるように光学異方性層の膜厚を調整して、それぞれの第１の位相差層用フィルムを作製した。

In addition, the thickness of the optically anisotropic layer was adjusted so that Re (550) and Rth (550) were values shown in the following table, and the respective first retardation layer films were prepared.

<Production method 3: Production of second retardation layer (pattern retarder)>
According to the following method, second retardation layer films used in the liquid crystal display devices of Examples and Comparative Examples using a 4-domain (4D) liquid crystal layer were produced.
<< Alkaline saponification treatment >>
The cellulose acylate film 001 was passed through a dielectric heating roll having a temperature of 60 ° C., and the film surface temperature was raised to 40 ° C., and then an alkali solution having the composition shown below was applied to one side of the film using a bar coater. The coating was carried out for 10 seconds under a steam far-infrared heater manufactured by Noritake Company Limited, which was applied at an amount of 14 ml / m ² and heated to 110 ° C. Subsequently, 3 ml / m ^{2 of} pure water was applied using the same bar coater. Next, washing with a fountain coater and draining with an air knife were repeated three times, followed by transporting to a drying zone at 70 ° C. for 10 seconds and drying to prepare an alkali saponified cellulose acetate transparent support.

(Alkaline solution composition)
Potassium hydroxide 4.7 parts by weight of water 15.8 parts by mass Isopropanol 63.7 parts by mass Surfactant _{SF-1: C 14 H 29} O (CH 2 CH 2 O) 20 H 1.0 part by weight・ 14.8 parts by mass of propylene glycol

<< Formation of rubbing alignment film >>
A rubbing alignment film coating solution having the following composition was continuously applied with a # 8 wire bar to the saponified surface of the prepared support. The alignment film was formed by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, a stripe mask having a horizontal stripe width of 100 μm in the transmission portion and a horizontal stripe width of 300 μm in the shielding portion is disposed on the rubbing alignment film, and is air-cooled with an illuminance of 2.5 mW / cm ² in the UV-C region under room temperature air. The first retardation layer alignment layer was formed by irradiating ultraviolet rays for 4 seconds using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.) to decompose the photoacid generator and generate an acidic compound. Thereafter, a rubbing treatment was performed once in one direction at 500 rpm to produce a transparent support with a rubbing alignment film. The alignment film had a thickness of 0.5 μm.

Composition of coating liquid for alignment film formation-Polymer material for alignment film (polyvinyl alcohol PVA103, manufactured by Kuraray Co., Ltd.)
3.9 parts by mass-Photoacid generator S-2 0.1 parts by mass-Methanol 36 parts by mass-Water 60 parts by mass

<< Formation of patterned optically anisotropic layer >>
After preparing the following optically anisotropic layer composition, it was filtered through a polypropylene filter having a pore size of 0.2 μm to obtain an optically anisotropic layer coating solution, which was applied at a coating amount of 8 ml / m ² using a bar coater. did. Next, after drying at a film surface temperature of 110 ° C. for 2 minutes to obtain a liquid crystal phase and uniformly aligning it, it was cooled to 100 ° C. and an air-cooled metal halide lamp (produced by Eye Graphics Co., Ltd.) of 20 mW / cm ² under air. The patterned optically anisotropic layer was formed by irradiating with ultraviolet rays for 20 seconds and fixing the alignment state. In the mask exposure part (first retardation layer), the slow axis direction is parallel to the rubbing direction and the discotic liquid crystal (DLC) is vertically aligned, and the unexposed part (second retardation layer) is orthogonal. Was vertically aligned. The film thickness of the optically anisotropic layer was 1.6 μm.

Composition for optically anisotropic layer, discotic liquid crystal E-1 100 parts by mass, alignment film interface aligner (II-1) 3.0 parts by mass, air interface aligner (P-1) 0.4 parts by mass, light Polymerization initiator (Irgacure 907, manufactured by BASF) 3.0 parts by mass / sensitizer (Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.0 part by mass / 400 parts by mass of methyl ethyl ketone

When the 1st phase difference layer and 2nd phase difference layer of the pattern optical film which were formed were analyzed by TOF-SIMS (time-of-flight type secondary ion mass spectrometry, ION-TOF company TOF-SIMS V), respectively In the first retardation layer and the second retardation layer, the abundance ratio (molar ratio) of the photoacid generator S-2 in the corresponding alignment layer is 8 to 92, and in the first retardation layer, It was found that S-2 was almost decomposed. In the optically anisotropic layer, the cation of II-1 and the anion BF ₄ ⁻ of acid HBF ₄ generated from the photoacid generator S-2 exist at the air interface of the first retardation layer. It was confirmed. These ions were hardly observed at the air interface of the second retardation layer, indicating that cations II-1 and Br- were present in the vicinity of the alignment film interface. The abundance ratio of each ion at the air interface was 93: 7 for II-1 cations and 90:10 for BF ₄ ⁻ . From this, in the second retardation layer, the alignment film interface aligning agent (II-1) is unevenly distributed at the alignment film interface, but the uneven distribution is reduced in the first retardation layer and also at the air interface. It can be understood that the diffusion of the II-1 cation is promoted by the anion exchange between the generated acid HBF ₄ and II-1 in the first retardation layer.
Further, the thickness of the optically anisotropic layer was adjusted so that Re (550) and Rth (550) were values shown in the following table, and respective second retardation layer films were prepared.

<Production method 4: Production of first retardation layer (pattern retarder)>
According to the following method, first retardation layer films used in the liquid crystal display devices of Examples and Comparative Examples using a 4-domain (4D) liquid crystal layer were produced.
An optically anisotropic layer is formed on the surface of the alignment film formed in the same manner as in the production of the second retardation layer (pattern retarder) using the method described in the examples of JP-T-2012-517024. As a rod-like liquid crystal (RLC), an LC242 made by BASF was used to form the first and second retardation layers.
In addition, the thickness of the optically anisotropic layer was adjusted so that Re (550) and Rth (550) were values shown in the following table, and the respective first retardation layer films were prepared.

<Preparation of Third Retardation Layer (Optical Compensation Film) (2-Layer Laminate Type)>
Regarding the production of the film 1 described in paragraph 0137 of JP2012-8548, Re (550) and Rth (550) are adjusted to the values in the table by adjusting the stretching ratio in the TD direction and the stretching ratio in the MD direction. It produced so that it might become. On this film, 1.8 g of a rod-like liquid crystal composition coating liquid (liquid crystal compound 1: liquid crystal compound 2 = 80: 20 mixed liquid) having the following composition, a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Co.) An air-cooled metal halide lamp (06 W) and a sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02 g was applied and vertically aligned, and an oxygen concentration of about 0.1% under a nitrogen purge and a 160 W / cm air-cooled metal halide lamp ( The fourth phase difference described in the table is formed by forming a layer obtained by irradiating ultraviolet rays having an illuminance of 190 mW / cm ² and an irradiation amount of 300 mJ / cm ² using an iGraphics Co., Ltd. A layer was made.

液晶化合物２

Liquid crystal compound 1

Liquid crystal compound 2

<Production of (Optical Compensation Film) (Single Layer Laminated Type) of Third Phase Layer>
(1) Dope preparation / cellulose acylate solution C
The following composition was put into a mixing tank, stirred to dissolve each component, further heated at 90 ° C. for about 10 minutes, and then 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.
―――――――――――――――――――――――――――――――――――――
Cellulose acylate solution C
―――――――――――――――――――――――――――――――――――――
Cellulose acylate (degree of substitution-benzoyl group: 0.86, acetyl group: 1.76)
100.0 parts by mass Dichloromethane 462.0 parts by mass ――――――――――――――――――――――――――――――――――――――

(2) Casting film formation After the dope was cast using a metal band casting machine and dried, the film was peeled off from the band by a peeling drum. In this way, an unstretched film was produced.

(3) Stretching The unstretched film produced above was stretched 10% in the tenter zone by (fixed end uniaxial stretching) in the film transport direction (MD) at (glass transition point Tg−stretching temperature) = − 5 ° C. Next, at the same temperature, 65% was stretched in the tenter zone by uniaxial stretching at the fixed end in the width direction (TD). In this manner, a biaxial stretching process was performed to produce a cellulose acylate film. The cast film thickness was adjusted so that the film thickness after stretching and drying was 60 μm.

The optical characteristics were measured, and it was confirmed that Re was 275 nm and Rth was 0 nm.
This retardation layer was used in place of the fourth retardation film of Example 1 and Example 2, and the others were manufactured in exactly the same manner as Example 1 and Example 2, and a new Example 13, Example 14 was taken.

<Production of liquid crystal display device>
<< Polarizing film >>
According to Example 1 of Unexamined-Japanese-Patent No. 2001-141926, the stretched polyvinyl alcohol film was made to adsorb | suck iodine, and the 20-micrometer-thick polarizing film was produced.

  Using the polyvinyl alcohol-based adhesive, the first retardation layer, the second retardation layer, and the third retardation layer are formed on one side of the polarizer so as to have the layer configuration shown in the following table and FIG. Either one was saponified. A commercially available cellulose acetate film (manufactured by Fuji Film, TD80) dried at 70 ° C. for 10 minutes or more and subjected to saponification treatment on the other surface was similarly bonded to obtain a laminate. In this way, a polarizing plate was produced.

<< Preparation of VA mode liquid crystal cell >>
A cell gap between the substrates is set to 3.6 μm, and a liquid crystal material having negative dielectric anisotropy (“MLC6608”, manufactured by Merck & Co., Inc.) is dropped and sealed between the substrates to form a liquid crystal layer between the substrates. Made. The retardation of the liquid crystal layer (that is, the product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn) was adjusted to the value d shown in the following table by adjusting the thickness d of the liquid crystal layer. The liquid crystal material was aligned so as to be vertically aligned. In this way, a VA mode liquid crystal cell was produced.
Of the manufactured liquid crystal display devices, in Example 15, the third retardation layer was provided between the second polarizing film and the second retardation layer.

In the above table, 2D indicates that the pixel of the liquid crystal cell has 2 domains, 4D indicates 4 domains, and 8D indicates 8 domains.
The slow axis and the absorption axis are angles in which the first polarizing film is 0 ° and the counterclockwise direction is a positive direction when viewed from the viewing side.

<Evaluation>
About the obtained liquid crystal display device, it evaluated as follows using measuring machine "EZ-Contrast XL88" (made by ELDIM).

<< White Jump >>
Set the front γ curve to 2.2 (100 x (each signal value / maximum value of signal value) to the power of 2.2 so that the normalized luminance of each signal value (value when white is 100)) The luminance at the signal value 128 and the luminance at the white display were measured. Next, the ratio (signal value 128 luminance / white luminance) at the polar angle of 60 ° in the four directions of front and up / down / left / right directions (azimuth angles 0 °, 90 °, 180 °, 270 °) was calculated. Furthermore, the difference between the front ratio and the average ratio of the up / down / left / right ratios was calculated and evaluated according to the following categories.
A: Difference is 0 or more and less than 0.05 B: Difference is 0.05 or more and less than 0.10 C: Difference is 0.10 or more and less than 0.15 D: Difference is 0.15 or more

<< with color >>
The difference between the front and the right direction (azimuth angle 0 °) at a polar angle of 60 ° was calculated by calculating Δu′v ′ using the following formula and evaluated according to the following classification.
(Δu'v '= √ (u'_Right-u'_Front) ^ 2 + (v'_Right-v'_Front) ^ 2)
A: Δu′v ′ is less than 0.005 B: Δu′v ′ is 0.005 or more and less than 0.01 C: Δu′v ′ is 0.01 or more

<< View angle contrast >>
The brightness in white display and the brightness in black display are measured, and the contrast ratio (white brightness / black brightness) at a polar angle of 60 ° in four directions is measured (azimuth angles 45 °, 135 °, 225 °, 315 °). Average values were calculated and evaluated according to the following categories.
A: Average value of contrast ratio is 10 or more B: Average value of contrast ratio is 5 or more and less than 10 C: Average value of contrast ratio is less than 5

<< Backlight (BL) light utilization efficiency >>
The luminance of white display and the luminance of only the backlight were measured, and the ratio (white luminance / backlight luminance) was calculated. Next, the ratio with Comparative Example 1 (the ratio of Example or Comparative Example / Ratio of Comparative Example 1) was calculated and evaluated according to the following categories.
A: Ratio is 105 or more B: Ratio is 102.5 or more and less than 105 C: Ratio is 100 or more and less than 102.5

<< Front contrast (CR) >>
The brightness in white display and the brightness in black display were measured, and the contrast ratio (white brightness / black brightness) at the front was calculated. Next, a ratio with the front contrast of Comparative Example 1 (front contrast of Example or Comparative Example / front contrast of Comparative Example 1) was calculated and evaluated according to the following categories.
A: Ratio is 98 or more B: Ratio is 90 or more and less than 98 C: Ratio is less than 90

These results are shown in the table below.

As is clear from the above table, in the liquid crystal display device of the present invention, overexposure was suppressed and tinting was suppressed. Also, the BL light temporary utilization efficiency was improved. Furthermore, the front contrast and viewing angle contrast were also excellent.
On the other hand, in the liquid crystal display device of the comparative example, it was difficult to achieve both suppression of overexposure and suppression of tint. Furthermore, it turned out that BL utilization efficiency is low, or it is inferior to front contrast and viewing angle contrast.

DESCRIPTION OF SYMBOLS 1, 11 1st polarizing film 2, 12 1st phase difference layer 3, 13 3rd phase difference layer 4, 14 Liquid crystal layer 5, 15 2nd phase difference layer 6, 17 2nd polarizing film 16 1st 4 retardation layer

Claims (6)

At least a first polarizing film, a first retardation layer, a liquid crystal layer, a second retardation layer, and a second polarizing film in that order,
The liquid crystal layer is in a vertical alignment mode (VA mode) when no voltage is applied with 4 domains or less,
The in-plane retardation Re (550) at a wavelength of 550 nm of the first retardation layer is 40 to 110 nm, and the retardation Rth (550) in the thickness direction at a wavelength of 550 nm of the first retardation layer is 400 to 500 nm. Yes,
Re (550) of the second retardation layer is 40 to 110 nm, Rth (550) of the second retardation layer is -200 to -100 nm,
The angle between the slow axis of the first retardation layer and the absorption axis of the first polarizing film is 45 °, and the slow axis of the first retardation layer and the surface of the liquid crystal layer when a voltage is applied It is orthogonal to the inner slow axis,
The angle formed by the slow axis of the second retardation layer and the absorption axis of the second polarizing film is 45 °, and the slow axis of the second retardation layer and the retardation of the first retardation layer are It is orthogonal to the phase axis,
A liquid crystal display device, wherein the liquid crystal layer has a retardation (Δnd) of 250 to 450 nm. The liquid crystal display according to claim 1, further comprising a third retardation layer between the first polarizing film and the first retardation layer, or between the second polarizing film and the second retardation layer. apparatus. The in-plane retardation Re (550) of the third retardation layer at a wavelength of 550 nm is 250 to 305 nm, and the retardation Rth (550) in the thickness direction at a wavelength of 550 nm is -30 to 30 nm. The liquid crystal display device described. The third retardation layer is an optically biaxial film having Re (550) of 70 to 140 nm and Rth (550) of 40 to 110 nm; and Re (550) of 10 nm or less; The liquid crystal display device according to claim 2, wherein (550) is a laminated film with a film having a thickness of −180 to −90 nm. The liquid crystal display device according to claim 1, wherein the liquid crystal layer includes two domains. The first retardation layer and the second retardation layer are pattern retardation layers, and the slow axis of the first retardation layer and the slow axis of the second retardation layer are orthogonal to each other. The liquid crystal display device according to claim 1.

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