JP2009237039A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display excellent in color viewing angle characteristics. <P>SOLUTION: The liquid crystal display includes at least a pair of polarizers 10 and 11, a liquid crystal cell LC interposed between the polarizers, optical anisotropic layers 14 and 15 interposed between each of the pair of polarizers and the liquid crystal cell, and a backlight unit (BL) disposed on the outside of the polarizer on the rear side out of the pair of polarizers. The liquid crystal display satisfies expression (1): Re(450)/Re(650)<1.25, wherein Re(450) and Re(650) are an in-plane retardation at a wavelength of 450 nm and an in-plane retardation at a wavelength of 650 nm in the optical anisotropic layers, respectively and satisfies expression (2): 1.1<I(450)/I(550)<5.0, wherein I(450) and I(550) are light intensity of incident light at a wavelength of 450 nm and light intensity of light at a wavelength of 550 nm incident on the liquid crystal cell from directions of an azimuth of 0° and a polar angle of 45°. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a TN (twisted nematic) mode liquid crystal display device.

The liquid crystal display device is used not only as a display unit of a personal computer but also as a display unit of a television or the like. However, the liquid crystal display device has a viewing angle dependency, and it is necessary to improve this. In particular, it is required to reduce the color shift that occurs in an oblique direction.
For example, Patent Documents 1 and 2 disclose that yellowness generated in the left-right direction during white display can be reduced by using a predetermined spectral anisotropic scattering film.
JP 2004-341308 A JP 2004-341309 A

However, when the inventors examined, by using the anisotropic scattering film, the yellowness at the time of white display is reduced, but the blueness generated in the vertical direction at the time of black display cannot be reduced, rather It turns out that it gets worse.
It is an object of the present invention to provide a liquid crystal display device excellent in color viewing angle characteristics in which not only the yellow tint generated in the left-right direction during white display but also the blue tint generated in the vertical direction of black display is reduced. To do.

Means for solving the above problems are as follows.
[1] A pair of polarizers, a liquid crystal cell disposed between the pair of polarizers, an optically anisotropic layer disposed between each of the pair of polarizers and the liquid crystal cell, and the pair of polarizers A liquid crystal display device having at least a backlight unit arranged on the outer side of the polarizer on the back side of the polarizer,
The in-plane retardation Re (450) of wavelength 450 nm and the in-plane retardation Re (650) of wavelength 650 nm of the optically anisotropic layer satisfy the following formula (1), and Re (450) / Re (650 ) <1.25 Formula (1)
The light intensity I (450) of incident light having a wavelength of 450 nm and the light intensity I (550) of incident light having a wavelength of 550 nm from the directions of an azimuth angle of 0 ° and a polar angle of 45 ° to the liquid crystal cell are expressed by the following formula (2 ) Satisfying the following conditions:
1.1 <I (450) / I (550) <5.0 ... Formula (2).
[2] The liquid crystal display device according to [1], wherein the optically anisotropic layer is a layer formed of a liquid crystal composition.
[3] The backlight unit includes a diffusing plate, and the scattering intensity D (450) of the emitted light having a wavelength of 450 nm and the emitted light having a wavelength of 550 nm from the directions of the azimuth angle of 0 ° and the polar angle of 45 ° of the diffusing plate. The liquid crystal display device of [1] or [2], wherein the scattering intensity D (550) satisfies the following formula (3):
1.1 <D (450) / D (550) <5.0 ... Formula (3).
[4] The liquid crystal display device according to any one of [1] to [3], wherein the diffusion plate contains particles having an average particle diameter (diameter) of 1.5 μm or less.
[5] The liquid crystal display device according to any one of [1] to [4], wherein the diffusion plate exhibits spectral anisotropic scattering.
[6] In the emission spectrum of the light source provided in the backlight unit, peak intensities P (B) and P (G) corresponding to blue light and green light in directions with an azimuth angle of 0 ° and a polar angle of 45 ° are expressed by the following formula ( 4) The liquid crystal display device according to any one of [1] to [5], wherein
1.1 <P (B) / P (G) <5.0 (4).
[7] In the emission spectrum of the light source provided in the backlight unit, the half-value widths of the blue, green, and red light peaks in the directions of the azimuth angle 0 ° and the polar angle 45 ° are 50 nm or less, respectively. The liquid crystal display device according to any one of [1] to [6].
[8] The liquid crystal display device according to any one of [1] to [7], wherein a light source included in the backlight unit is an LED.
[9] The liquid crystal surface device has a colored layer, and the transmittance T (450) of light having a wavelength of 450 nm and the absorbance T of light having a wavelength of 550 nm in the directions of an azimuth angle of 0 ° and a polar angle of 45 ° of the colored layer. (550) satisfies the following formula (5): The liquid crystal display device according to any one of [1] to [8]:
T (450) / T (550)> 1.0 (5)
[10] The liquid crystal display device according to any one of [1] to [9], wherein the liquid crystal cell is in a TN mode.

  According to the present invention, it is possible to provide a liquid crystal display device excellent in color viewing angle characteristics in which not only the yellow tint generated in the left-right direction during white display but also the blue tint generated in the vertical direction of black display is reduced. it can.

  The present invention will be described below. In the present specification, a numerical range represented using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method. 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.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light of wavelength λ nm is incident from each of the inclined directions in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction (with the direction of the rotation axis as the rotation axis). KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is changed to KOBRA 21ADH or WR after changing its sign to negative.
The retardation value is measured from two inclined directions with the slow axis as the tilt axis (rotation axis) (if there is no slow axis, the arbitrary direction in the film plane is the rotation axis). Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following formulas (I) and (II).

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あらわす。
また、ｎｘは、面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表し、ｄは膜厚を表す。

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

When the film to be measured is a film that cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotary axis), and −50 degrees to +50 degrees with respect to the film normal direction. Measured at 11 points by making light of wavelength λ nm incident from each tilted direction in 10 degree steps, and based on the measured retardation value, assumed value of average refractive index, and input film thickness value KOBRA 21ADH or WR is calculated.
In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical compensation films can be used.
Moreover, about the thing whose average refractive index value is not known, it can measure with an Abbe refractometer. Examples of the average refractive index values of main optical compensation films are as follows:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  In the present specification, “45 °”, “parallel” or “orthogonal” means that the angle is within a range of strictly less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Regarding the angle, “+” means the clockwise direction, and “−” means the counterclockwise direction. Further, the “slow axis” means a direction in which the refractive index is maximized. The “visible light region” means 380 to 780 nm. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.

  Further, in this specification, the “polarizing plate” is cut into a size to be incorporated into a long polarizing plate and a liquid crystal device unless otherwise specified (in this specification, “cutting” includes “punching” and The term “includes“ cutout ”and the like” is used to include both polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other. “Polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. It shall be.

  In this specification, the “azimuth angle” is an angle in a plane parallel to the display surface, and the horizontal direction of the display surface is 0 ° azimuth and the vertical direction of the display surface is 90 ° azimuth. The “polar angle” is an angle in a plane perpendicular to the display surface. The direction in the display surface is a polar angle of 0 °, and the normal direction of the display surface is a polar angle of 90 °. In the following description, the direction of the azimuth angle 0 ° and the polar angle 45 ° shown in FIG. 2 is expressed as “45 ° direction”.

One embodiment of the present invention is a TN liquid crystal display device using twisted alignment. FIG. 1 shows a schematic sectional view of an example of a TN liquid crystal display device of the present invention. In FIG. 1, the relative relationship between the thicknesses of the respective layers does not necessarily match the relative relationship between the thicknesses of the respective members in the actual liquid crystal display device.
1 includes a liquid crystal cell LC and a pair of polarizers 110 and 11 disposed therebetween, and a pair of polarizers 10 and 11 disposed between the liquid crystal cell LC. It has optical compensation films F1 and F2. Further, a backlight unit BL is provided on the back surface of the polarizer 11. The backlight unit is generally composed of a plurality of members such as a light source, a light guide plate, and a light diffusion plate, but the detailed structure is omitted in FIG.

  A normal TN mode liquid crystal cell can be used as the liquid crystal cell LC. Specifically, the liquid crystal cell LC has a pair of opposed substrates and a liquid crystal layer made of a liquid crystal material therebetween. Transparent electrodes for forming a plurality of pixels by regions facing each other are provided on the opposing surfaces of the pair of substrates, for example, corresponding to the plurality of pixels on the opposing surface of the display surface side substrate (upper side in FIG. 1). Three color filters of red, green, and blue are provided, and a counter electrode is formed thereon. The electrodes formed on the inner surface of the back side substrate (lower side in FIG. 1) are a plurality of pixel electrodes arranged in a matrix in the row direction and the column direction, and the electrodes formed on the inner surface of the display surface side substrate are: It is a single-film counter electrode facing the plurality of pixel electrodes. However, it is not limited to this configuration.

  In addition, a horizontal alignment film that is aligned in a direction substantially orthogonal to each other is formed on the opposing surfaces of the pair of substrates so as to cover the electrodes. The liquid crystal layer is a layer formed by filling a nematic liquid crystal material having a positive dielectric anisotropy, and the liquid crystal molecules are aligned in the vicinity of the inner surface of the substrate by a horizontal alignment film, and an electric field is generated between the electrodes. When not applied, it is twisted with a twist angle of substantially 90 ° between the substrates. On the other hand, when a black display voltage is applied between the electrodes, the liquid crystal molecules rise vertically and are substantially vertically aligned. As described above, in the normally white mode, the liquid crystal cell LC is in a twist alignment state during white display and is substantially in a vertical alignment state during black display. In general, in a TN mode liquid crystal display device, a yellow color shift is observed in the horizontal direction with respect to the display surface during white display, and a blue color shift is observed in the vertical direction with respect to the display surface during black display. Is done. In the present invention, an optical anisotropic layer that satisfies the optical characteristics described later is used, and the color shift is reduced by adjusting the incident light to the liquid crystal cell to satisfy a predetermined condition.

A pair of optical compensation films F1 and F2 are disposed between the liquid crystal cell LC and the pair of polarizing plates 10 and 11, respectively. Each of the optical compensation films F1 and F2 has optical anisotropic layers 14 and 15 that satisfy the following formula (1) on one surface of each of the transparent support films 12 and 13.
Re (450) / Re (650) <1.25 (1)
By satisfying the above formula (1), bluishness generated in the vertical direction during black display can be reduced. From the viewpoint of effect, Re (450) / Re (650) is preferably 1.22 or less, and more preferably 1.18 or less. In the optically anisotropic layer, Re is preferably forward wavelength dispersive (Re is larger as the wavelength is smaller) in the visible light region. From this viewpoint, Re (450) / Re (650) exceeds 1. And preferably less than 1.25.
In addition, the optically anisotropic layer satisfying the above formula (1) can be prepared by using a discotic liquid crystal compound represented by a predetermined formula described later.

  The optically anisotropic layers 14 and 15 are layers formed by fixing a discotic liquid crystal in a desired alignment state. For example, it can be produced by applying a polymerizable discotic liquid crystal to the alignment treatment surface of the alignment film, aligning it along the alignment treatment direction (generally a rubbing axis), and fixing the alignment state. The tilt angle with respect to the film surface of the discotic liquid crystal molecules (here, the tilt angle with respect to the film surface of the discotic liquid crystal molecules) changes in the thickness direction (for example, the tilt angle at the interface with the alignment film surface is minimum, The optically anisotropic layer can be produced by fixing in a so-called hybrid orientation state (increasing in the thickness direction and maximizing the tilt angle at the air interface).

  Polymer films are used for the transparent support films 12 and 13 of the optical compensation films F1 and F2. Polymer films made of various materials can be used, but the polarizers 10 and 11 are brought into contact with each other (however, the adhesive layer may be interposed) and bonded as a protective film. The support films 12 and 13 are preferably made of a material having affinity with the material of the polarizers 10 and 11. In this respect, considering that the polarizer is generally a polyvinyl alcohol film, a cellulose acylate film such as triacetyl cellulose is preferable. However, the present invention is not limited to this, and norbornene resin films, polycarbonate films, and the like can also be preferably used. The optical properties of the support films 12 and 13 are not particularly limited, but generally it is preferable that Re (550) is about 0 to 20 nm and Rth (550) is about 40 to 120 nm. .

  As described above, the support films 12 and 13 of the optical compensation films F1 and F2 may also function as protective films for the polarizers 10 and 11, respectively, that is, the optical compensation films F1 and F2 are polarized light. It may be bonded to the children 10 and 11 and used in a liquid crystal display device as one member of the polarizing plates P1 and P2.

  The liquid crystal display device shown in FIG. 1 is in a normally white mode, and the pair of polarizers 10 and 11 are arranged with their absorption axes substantially orthogonal to each other. The polarizer has protective films 16 and 17 on the outer surface and optical compensation films F1 and F2 on the liquid crystal cell side surface. The optical axis relationship of each member in the liquid crystal display device of FIG. 1 is the same as that of the conventional normally white mode TN mode liquid crystal display device. As an example, the alignment processing direction (usually the rubbing axis) of the alignment film formed on the opposite surface of the display surface side cell substrate is viewed from the display surface side (upper side of the drawing) with respect to the horizontal direction of the screen of the liquid crystal display device. The orientation processing direction of the orientation film formed on the opposite surface of the back side cell substrate is 45 ° counterclockwise and the viewing direction from the viewer side (upper side of the drawing) with respect to the horizontal direction of the screen of the liquid crystal display device. In the direction rotated clockwise by 45 °. The polarizer 10 is arranged with its absorption axis parallel to the alignment treatment direction of the display surface side alignment film, and the polarizer 11 has its absorption axis substantially orthogonal to the absorption axis of the polarizer 10. Are arranged. The rubbing axis of the alignment film used for forming the optically anisotropic layer 14 on the display surface side is substantially parallel to the alignment treatment direction of the alignment film on the display surface side cell substrate, and the back side The rubbing axis of the alignment film used for forming the optically anisotropic layer 15 is substantially parallel to the alignment treatment direction of the alignment film of the back side cell substrate. However, the arrangement is not limited to this, and the arrangement is not necessarily limited depending on the material used for forming the optically anisotropic layer, the kind of the alignment film, and the like.

Furthermore, in the liquid crystal display device of FIG. 1, the incident light from the backlight unit BL satisfies the following formula (2).
1.1 <I (450) / I (550) <5.0 ..... Formula (2)
In the formula, I (450) is the light intensity of incident light with a wavelength of 450 nm from the 45 ° direction to the liquid crystal cell, and I (550) is the light intensity of incident light with a wavelength of 550 nm from the same direction. . By satisfying the above formula (2), that is, by increasing the bluishness of the incident light in the 45 ° direction, it is possible to reduce the yellowishness generated in the left-right direction during white display. From the same viewpoint, I (450) / I (550) is preferably 1.2 to 4.0, and more preferably 1.3 to 3.0. When I (450) / I (550) is less than 1.1, the above-described effect is insufficient. On the other hand, when it is 5.0 or more, bluishness in the vertical direction is increased, which is not preferable.

  The light intensity of the incident light can be adjusted according to the characteristics of the diffusion plate used and / or the emission spectral characteristics of the light source used. Separately, a colored layer satisfying a predetermined absorption characteristic can be adjusted by disposing it between the backlight unit and the liquid crystal cell. Hereinafter, each embodiment will be described.

In the present invention, in order to satisfy the formula (2), it is preferable to use a diffusion plate that satisfies the following formula (3).
1.1 <D (450) / D (550) <5.0 ... Formula (3)
In the above formula, D (450) is the scattering intensity of the outgoing light with a wavelength of 450 nm from the 45 ° direction of the diffuser plate, and D (550) is the scattering of the outgoing light with a wavelength of 550 nm from the same direction of the diffuser plate. It is strength. The diffuser plate is usually disposed on the surface of the backlight unit and contributes to the improvement of viewing angle characteristics. In the present invention, it is preferable to use a light diffusion plate that has a wavelength dependency satisfying the expression (3) with respect to the scattering intensity in the 45 ° direction, that is, the blue light is more scattered in the 45 ° direction. In view of the effect, D (450) / D (550) is preferably 1.2 to 4.0, and more preferably 1.3 to 3.0. A diffusion plate satisfying such characteristics will be described later.

In the present invention, in order to satisfy the formula (2), it is preferable to use a light source that satisfies the following formula (4).
1.1 <P (B) / P (G) <5.0 Formula (4)
In the formula, the intensities P (B) and P (G) are peak intensities corresponding to blue light and green light in the 45 ° direction in the emission spectrum of the light source provided in the backlight unit, respectively. That is, in the present invention, the intensity of blue light and green light is not uniform in the emission spectrum in the 45 ° direction, and satisfies the above formula (4), that is, the intensity of blue light in the 45 ° direction is greater than the intensity of green light. It is preferable to use a high light source. From the viewpoint of the effect, P (B) / P (G) is preferably 1.2 to 4.0, and more preferably 1.3 to 3.0. As the light source, for example, an LED light source including a plurality of blue light emitting diodes, green light emitting diodes, and red light emitting diodes is preferably used. For example, an LED light source that satisfies the formula (4) can be produced by unevenly arranging the light emitting diodes of the respective colors. Moreover, the said Formula (4) can be satisfied by controlling the spatial light quantity distribution of the emitted light of each color from a LED light source. Japanese Patent Application Laid-Open No. 2006-339047 discloses a method for changing the spatial light quantity distribution of light emitted from the LED light source. Further, it is also preferable that the backlight unit individually controls the emission spectrum in the normal direction of the light emitting surface and the 45 ° direction. By individually controlling the brightness of the light emitting diodes of each color and each position or each block, the directivity and the light emission intensity can be set in desired ranges, and the above formula (4) can be satisfied.

  In addition, it is preferable that the half-value widths of the blue light, green light, and red light peaks in the 45 ° direction of the light emission spectrum of the light source used in the present invention be 50 nm or less, respectively, because color reproducibility can be widened. From this point of view, the smaller the half width, the better. However, if it is too small, the transmittance decreases, and power consumption increases in order to increase the transmittance. Therefore, the half width is preferably 10 to 50 nm, more preferably 20 to 40 nm. The LED light source satisfies this characteristic.

Moreover, in this invention, in order to satisfy | fill said Formula (2), you may utilize the colored layer which satisfies following formula (5).
T (450) / T (550)> 1.0 ..... Formula (5)
In the formula, T (450) and T (550) are transmittances T of light having wavelengths of 450 nm and 550 nm, respectively, in the 45 ° direction of the colored layer. It is preferable to arrange the colored layer having such characteristics in an optical path from the light emitted from the backlight to the liquid crystal cell. From the viewpoint of effects, T (450) / T (550) is preferably 1.1 to 4.0, and more preferably 1.2 to 3.0. The colored layer will be described later.

  In the above description, the embodiment of the TN mode liquid crystal display device has been described. However, the present invention can provide the same effect even in a mode that does not use the twisted orientation such as the VA mode, the IPS mode, the ECB mode, and the OCB mode. Will.

Hereinafter, various members used in the liquid crystal display device of the present invention will be described in detail.
(Optical compensation film)
The optical compensation film used in the present invention has an optically anisotropic layer that satisfies the formula (1). As described above, Re (450) / Re (650) of the optically anisotropic layer is preferably 1.22 or less, and more preferably 1.18 or less. In the optically anisotropic layer, Re is preferably forward wavelength dispersive (Re is larger as the wavelength is smaller) in the visible light region. From this viewpoint, Re (450) / Re (650) exceeds 1. And preferably less than 1.25.

  The optically anisotropic layer exhibits optical characteristics for compensating the birefringence of the liquid crystal cell. In this respect, Re (550) of the optically anisotropic layer is preferably 20 to 40 nm, and more preferably 25 to 40 nm. The optically anisotropic layer is preferably designed so as to compensate for the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device. Regarding the alignment state of the liquid crystal compound in the liquid crystal cell, IDW'00, FMC7-2, p. 411-414

An example of the optically anisotropic layer is a layer formed by curing a liquid crystal composition. As the liquid crystal composition, either a rod-like liquid crystal or a disk-like liquid crystal may be used. A discotic liquid crystal is preferred. The discotic liquid crystal compound may be a polymer liquid crystal or a low molecular liquid crystal, and further includes those in which the low molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity.
Examples of the discotic liquid crystal compound include a benzene derivative (research report of C. Destrade et al., Mol. Cryst. 71, 111 (1981)), a truxene derivative (research report of C. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990)), cyclohexane derivatives (research report of B. Kohne et al., Angew. Chem. 96, 70 ( 1984)) and azacrown or phenylacetylene macrocycle (JM Lehn et al., J. Chem. Commun., 1794 (1985), J. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994)) Is included.

The discotic liquid crystal compound exhibits liquid crystallinity with a structure in which a linear alkyl group, an alkoxy group, or a substituted benzoyloxy group is radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule. Also included are compounds. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation.
When an optically anisotropic layer is formed from a discotic liquid crystal compound, the compound finally contained in the optically anisotropic layer no longer needs to exhibit liquid crystallinity.
For example, a low molecular discotic liquid crystal compound has a group that reacts with heat or light, and the group reacts with heat or light to polymerize or crosslink, thereby increasing the molecular weight. Is formed, the compound contained in the optically anisotropic layer may no longer have liquid crystallinity.
Preferred examples of the discotic liquid crystal compound are described in JP-A-8-50206, and the polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.

  In order for the optically anisotropic layer to satisfy the above formula (1), it is preferable that the birefringence of the liquid crystal used for production also exhibits the same wavelength dependence as the above formula (1). From this viewpoint, it is preferable to produce the optically anisotropic layer by using at least one discotic liquid crystal compound represented by the following formula (DI).

In the above general formula (DI), Y ¹¹ , Y ¹² , and Y ¹³ each independently represent a methine or a nitrogen atom.

When Y ¹¹ , Y ¹² , and Y ¹³ are methine, the hydrogen atom of methine may be substituted with a substituent. Here, methine refers to an atomic group obtained by removing three hydrogen atoms from methane.
Examples of the substituent that the carbon atom of methine may have include an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an alkylthio group, an arylthio group, Preferred examples include halogen atoms and cyano groups.
Among these substituents, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, a halogen atom and a cyano group are more preferable, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and a carbon number A 2-12 alkoxycarbonyl group, a C2-C12 acyloxy group, a halogen atom, and a cyano group are still more preferable.
Y ¹¹ , Y ¹² and Y ¹³ are more preferably methine, and methine is more preferably unsubstituted.

In the general formula (DI), L ¹ , L ² , and L ³ each independently represent a single bond or a divalent linking group. When L ¹ , L ² , and L ³ are divalent linking groups, each independently represents —O—, —S—, —C (═O) —, —NR ⁷ —, —CH═CH—, A divalent linking group selected from the group consisting of —C≡C—, a divalent cyclic group, and combinations thereof is preferable.
R ⁷ is an alkyl group having 1 to ⁷ carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is particularly preferably a hydrogen atom.

The divalent cyclic group in L ¹ , L ² , and L ³ is a divalent linking group having at least one cyclic structure (hereinafter sometimes referred to as a cyclic group). The cyclic group preferably has a 5-membered ring, a 6-membered ring, or a 7-membered ring, more preferably has a 5-membered ring or a 6-membered ring, and still more preferably has a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is preferably a monocycle rather than a condensed ring.
Further, the ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Preferred examples of the aromatic ring include a benzene ring and a naphthalene ring.
A preferable example of the aliphatic ring is a cyclohexane ring.
Preferred examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.
The cyclic group is more preferably an aromatic ring or a heterocyclic ring. The cyclic group is more preferably a divalent linking group consisting of only a cyclic structure (including a substituent).

Of the divalent cyclic groups represented by L ¹ , L ² and L ³ , the cyclic group having a benzene ring is preferably a 1,4-phenylene group.
As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl group and naphthalene-2,6-diyl group are preferable.
The cyclic group having a cyclohexane ring is preferably a 1,4-cyclohexylene group.
As the cyclic group having a pyridine ring, a pyridine-2,5-diyl group is preferable.
The cyclic group having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group.

The divalent cyclic group represented by L ¹ , L ² and L ³ may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkynyl group having 2 to 16 carbon atoms, and 1 to 1 carbon atoms. 16 halogen-substituted alkyl groups, alkoxy groups having 1 to 16 carbon atoms, acyl groups having 2 to 16 carbon atoms, alkylthio groups having 1 to 16 carbon atoms, acyloxy groups having 2 to 16 carbon atoms, carbon atoms Examples include an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, a carbamoyl group substituted with an alkyl group having 2 to 16 carbon atoms, and an acylamino group having 2 to 16 carbon atoms.

L ¹ , L ² , and L ³ include a single bond, * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C—, * —divalent cyclic group. -, * -O-CO-divalent cyclic group-, * -CO-O-divalent cyclic group-, * -CH = CH-divalent cyclic group-, * -C≡C-divalent Cyclic group-, * -divalent cyclic group-O-CO-, * -divalent cyclic group-CO-O-, * -divalent cyclic group-CH = CH-, and * -divalent cyclic group. The group -C≡C- is preferred.
Among these, a single bond, * —CH═CH—, * —C≡C—, * —divalent cyclic group —O—CO—, * —CH═CH—divalent cyclic group—, and * —C. ≡C-divalent cyclic group- is more preferable, and a single bond is still more preferable.
Here, the above “*” represents a position bonded to the 6-membered ring side including Y ¹¹ , Y ¹² , and Y ¹³ in the general formula (DI).

H ¹ , H ² , and H ³ each independently represent the following general formula (DI-A) or the following general formula (DI-B).

In General Formula (DI-A), YA ¹ and YA ² each independently represent a methine or a nitrogen atom. It is preferable that at least one of YA ¹ and YA ² is a nitrogen atom, and it is more preferable that both are nitrogen atoms. XA represents an oxygen atom, a sulfur atom, methylene, or imino, and preferably an oxygen atom.
Here, in the above general formula (DI-A), "*" represents the position at which the group bonds to L ¹ ~L ³ side in formula (DI), "**" is R in formula (DI) ^{1 to} R ³ represents the position of binding. The imino is represented by -NH- (including those in which H is substituted with a substituent).

In the general formula (DI-B), YB ¹ and YB ² each independently represent a methine or a nitrogen atom. It is preferable that at least one of YB ¹ and YB ² is a nitrogen atom, and it is more preferable that both are nitrogen atoms.
XB represents an oxygen atom, a sulfur atom, methylene or imino, preferably an oxygen atom.
Here, in the above general formula (DI-B), "*" represents the position at which the group bonds to L ¹ ~L ³ side in formula (DI), "**" is the general formula (DI) It represents a position bonded with R ¹ to R ³ side in.

R ¹ , R ² , and R ³ each independently represent the following general formula (DI-R).

In the above general formula (DI-R), “*” represents a position bonded to the H ^{1 to} H ³ side in the general formula (DI).

In the general formula (DI-R), L ²¹ is a single bond or a divalent linking group. When L ²¹ is a divalent linking group, it consists of —O—, —S—, —C (═O) —, —NR ⁷ —, —CH═CH—, C≡C—, and combinations thereof. A divalent linking group selected from the group is preferred. R ⁷ is an alkyl group having 1 to ⁷ carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and more preferably a methyl group, an ethyl group or a hydrogen atom. A hydrogen atom is preferable, and a hydrogen atom is particularly preferable.

In the general formula (DI-R), L ²¹ represents a single bond, ***-O-CO-, ***-CO-O-, ***-CH = CH-, and *. Any one of **-C≡C- (where “***” represents the “*” side in the general formula (DI-R)) is preferable, and a single bond is more preferable.

In the general formula (DI-R), Q ² represents a divalent group (cyclic group) having at least one kind of cyclic structure. As such a cyclic group, a cyclic group having a 5-membered ring, a 6-membered ring, or a 7-membered ring is preferable, a cyclic group having a 5-membered ring or a 6-membered ring is more preferable, and a cyclic group having a 6-membered ring is Particularly preferred. The cyclic structure contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring.
Further, the ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Preferred examples of the aromatic ring include a benzene ring and a naphthalene ring.
A preferable example of the aliphatic ring is a cyclohexane ring.
Preferred examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.
The cyclic group is more preferably an aromatic ring or a heterocyclic ring. The cyclic group is more preferably a divalent linking group consisting of only a cyclic structure (including a substituent).

In the general formula (DI-R), among Q ² , the cyclic group having a benzene ring is preferably a 1,4-phenylene group.
Moreover, as a cyclic group having a naphthalene ring, a naphthalene-1,5-diyl group and a naphthalene-2,6-diyl group are preferable.
Further, the cyclic group having a cyclohexane ring is preferably a 1,4-cyclohexylene group.
The cyclic group having a pyridine ring is preferably a pyridine-2,5-diyl group.
The cyclic group having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group. Among these, a 1,4-phenylene group and a 1,4-cyclohexylene group are particularly preferable.

In the general formula (DI-R), Q ² may have a substituent. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, nitro group, alkyl group having 1 to 16 carbon atoms, alkenyl group having 2 to 16 carbon atoms, carbon An alkynyl group having 2 to 16 atoms, an alkyl group substituted with a halogen having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an acyl group having 2 to 16 carbon atoms, and 1 to 16 carbon atoms An alkylthio group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, an alkyl-substituted carbamoyl group having 2 to 16 carbon atoms, and an acylamino group having 2 to 16 carbon atoms Is included.
Among these, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, and an alkyl group substituted with a halogen having 1 to 6 carbon atoms are preferable, a halogen atom, an alkyl group having 1 to 4 carbon atoms, An alkyl group substituted with a halogen having 1 to 4 carbon atoms is more preferable, and a halogen atom, an alkyl group having 1 to 3 carbon atoms, and a trifluoromethyl group are particularly preferable.

  n1 represents the integer of 0-4. As n1, the integer of 1-3 is preferable and 1 or 2 is still more preferable.

L ²² is **-O-, **-O-CO-, **-CO-O-, **-O-CO-O-, **-S-, **-N (R)-, ** — CH ₂ —, ** — CH═CH—, or ** — C≡C— is represented, and “**” represents a position bonded to the Q ² side.
L ²² is preferably ** — O—, ** — O—CO—, ** — CO—O—, ** — O—CO—O—, ** — CH ₂ —, ** — CH. ═CH—, ** — C≡C—, more preferably ** — O—, ** — O—CO—, ** — O—CO—O—, ** — CH ₂ —. .

L ²³ is selected from the group consisting of —O—, —S—, —C (═O) —, —NH—, —CH ₂ —, —CH═CH— and C≡C—, and combinations thereof. Represents a divalent linking group.
Here, the hydrogen atoms of —NH—, —CH ₂ —, and —CH═CH— may be substituted with a substituent.
Examples of such a substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, an alkyl group substituted with a halogen having 1 to 6 carbon atoms, and an alkoxy having 1 to 6 carbon atoms. Group, an acyl group having 2 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and 2 carbon atoms Preferred examples include a carbamoyl group substituted with -6 alkyl and an acylamino group having 2 to 6 carbon atoms, and a halogen atom and an alkyl group having 1 to 6 carbon atoms are more preferred.

L ²³ is preferably selected from the group consisting of —O—, —C (═O) —, —CH ₂ —, —CH═CH—, C≡C—, and combinations thereof.
L ²³ preferably contains 1 to 20 carbon atoms, more preferably 2 to 14 carbon atoms. Furthermore, L ²³ preferably contains 1 to 16 —CH ₂ —, and more preferably ₂ to 12 —CH ₂ —.

Q ¹ represents a polymerizable group or a hydrogen atom. When the liquid crystal compound used in the present invention is used for an optical compensation film in which the retardation does not change due to heat, Q ¹ is preferably a polymerizable group.
The polymerization reaction is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. That is, 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.

  Furthermore, the polymerizable group is particularly preferably a functional group capable of addition polymerization reaction. As such a polymerizable group, a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group is preferable.

  Examples of the polymerizable ethylenically unsaturated group include the following formulas (M-1) to (M-6).

In formulas (M-3) and (M-4), R represents a hydrogen atom or an alkyl group, and among them, a hydrogen atom or a methyl group is preferable.
Among the above formulas (M-1) to (M-6), the polymerizable ethylenically unsaturated group of the present invention is preferably (M-1) or (M-2), and (M-1) is More preferred.

  The ring-opening polymerizable group is preferably a cyclic ether group, more preferably an epoxy group or oxetanyl group, and particularly preferably an epoxy group.

  As the liquid crystal compound used in the present invention, a liquid crystal compound represented by the following general formula (DII) is particularly preferable.

In General Formula (DII), Y ³¹ , Y ³² , and Y ³³ each independently represent a methine or nitrogen atom, and have the same meaning as Y ¹¹ , Y ¹² , and Y ¹³ in General Formula (DI), The preferred range is also synonymous.

In the general formula (DII), R ³¹ , R ³² , and R ³³ each independently represent the following general formula (DII-R).

In the general formula (DII-R), A ³¹ and A ³² each independently represent a methine or nitrogen atom, preferably at least one is a nitrogen atom, and more preferably both are nitrogen atoms. X ³ represents an oxygen atom, a sulfur atom, methylene, or imino, and among them, an oxygen atom is preferable.

Q ³¹ represents a divalent linking group having a 6-membered cyclic structure (hereinafter sometimes referred to as a 6-membered cyclic group).
The 6-membered ring may be a condensed ring. However, it is more preferably a monocycle than a condensed ring.
The ring contained in the 6-membered cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Preferred examples of the aromatic ring include a benzene ring and a naphthalene ring.
A preferable example of the aliphatic ring is a cyclohexane ring.
Preferred examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.
Q ³¹ is preferably a divalent linking group consisting of only a 6-membered cyclic structure (which may have a substituent).

Of Q ^31, the 6-membered cyclic group having a benzene ring is preferably a 1,4-phenylene group or a 1,3-phenylene group.
As the cyclic structure having a naphthalene ring, a naphthalene-1,5-diyl group and a naphthalene-2,6-diyl group are preferable.
The cyclic structure having a cyclohexane ring is preferably a 1,4-cyclohexylene group.
The cyclic structure having a pyridine ring is preferably a pyridine-2,5-diyl group.
The cyclic structure having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group. Among these, a 1,4-phenylene group and a 1,3-phenylene group are particularly preferable.

The cyclic structure of Q ³¹ may have a substituent. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, nitro group, alkyl group having 1 to 16 carbon atoms, alkenyl group having 2 to 16 carbon atoms, carbon An alkynyl group having 2 to 16 atoms, an alkyl group substituted with a halogen atom having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an acyl group having 2 to 16 carbon atoms, and 1 to 1 carbon atoms 16 alkylthio groups, acyloxy groups having 2 to 16 carbon atoms, alkoxycarbonyl groups having 2 to 16 carbon atoms, carbamoyl groups, alkyl-substituted carbamoyl groups having 2 to 16 carbon atoms, and acylamino having 2 to 16 carbon atoms A group is included.
The substituent of the 6-membered cyclic group is preferably a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, or an alkyl group substituted with a halogen atom having 1 to 6 carbon atoms. An alkyl group substituted with a C 1-4 alkyl group or a C 1-4 halogen atom is more preferred, and a halogen atom, a C 1-3 alkyl group, or a trifluoromethyl group is more preferred.

  n3 represents an integer of 1 to 3, and preferably 1 or 2.

L ³¹ is * -O-, * -O-CO-, * -CO-O-, * -O-CO-O-, * -S-, * -N (R)-, * -CH _2-. , * —CH═CH—, or * —C≡C—.
In addition, “*” represents a position bonded to the Q ³¹ side, specifically, is synonymous with L ²² in the general formula (DI-R), and a preferred range is also synonymous.

L ³² is selected from the group consisting of —O—, —S—, —C (═O) —, —NH—, —CH ₂ —, —CH═CH—, C≡C—, and combinations thereof. It represents a divalent linking group, specifically, the general formula has the same meanings as (DI-R) in L ^23, and the preferred range is also the same.

Q ³² in the general formula (DII-R) represents a polymerizable group or a hydrogen atom, and specifically has the same meaning as Q ¹ in the general formula (DI-R), and the preferred range is also the same. It is.

  Specific examples of the liquid crystal compound represented by the general formula (DI) are shown below, but the present invention is not limited thereto.

  The liquid crystal compound used in the present invention desirably exhibits a liquid crystal phase exhibiting good monodomain properties. By making the monodomain property favorable, it is possible to effectively prevent the resulting structure from becoming a polydomain, causing an alignment defect at the boundary between domains, and scattering light. Furthermore, it is preferable to exhibit good monodomain properties because the retardation plate has a higher light transmittance.

  Examples of the liquid crystal phase expressed by the liquid crystal compound used in the present invention include a columnar phase and a discotic nematic phase (ND phase). Among these liquid crystal phases, a discotic nematic phase (ND phase) that exhibits good monodomain properties and can be hybrid-aligned is particularly preferable.

  The liquid crystal compound used in the present invention is better as the anisotropic wavelength dispersion is smaller. Specifically, Re (450) / Re (650) is less than 1.25, where Re (λ) is the phase difference (in-plane retardation value (nm) of the liquid crystal layer at wavelength λ) expressed by the liquid crystal compound. Preferably, it is 1.20 or less, more preferably 1.15 or less.

In order to align the liquid crystal compound used in the present invention on an alignment film provided on a support, the isotropic phase transition temperature T _iso (° C.) is preferably 100 <T _iso <180, and 100 < T _iso ≦ 165 ° C. is more preferable, and 100 <T _iso ≦ 150 ° C. is particularly preferable.
Further, the liquid crystal compound used in the present invention preferably satisfies 0 <| Re ( _Tiso- 50) -Re ( _Tiso- 30) | <10.
Here, the isotropic phase transition temperature of a liquid crystal compound is a state in which there is no alignment order from a temperature at which single or mixture of liquid crystal molecules exhibiting liquid crystallinity is aligned in a certain direction (so-called liquid crystal state). The temperature at which switching to a so-called isotropic state is shown.
This isotropic phase transition temperature can be determined by texture observation with a polarizing microscope. For example, when a liquid crystal compound is placed on a glass plate and observed with a polarizing microscope while heating, the liquid crystal state in which the field of view is bright changes from the liquid state in which the field of vision appears dark (optically isotropic state). The temperature was taken.

  In order to form an optically anisotropic layer satisfying the formula (1), it is also preferable to use two or more liquid crystal compounds in combination. An example of a preferable combination is a combination of at least one compound represented by the general formula (DI) and at least one triphenylene liquid crystal. An example of the triphenylene liquid crystal is a compound represented by the formula (D4) described in [0143] of JP-A No. 2001-166144. For details, reference can be made to [0141] to [0160] of the publication. In the embodiment used in combination, it is preferable to increase the amount of the compound represented by the formula (DI).

The plasticizer and polymerizable monomer used together with the liquid crystal compound of the present invention are compatible with the liquid crystal compound of the present invention and can change the tilt angle of the discotic liquid crystal compound or do not inhibit the alignment. Is done.
The surfactant is preferably a compound containing a fluoroaliphatic group. As the fluorine-based surfactant, for example, a compound represented by the following structural formula can be used.

The polymer and the low molecular compound preferably change the tilt angle of the discotic liquid crystal compound.
The polymer is preferably a cellulose ester. As the cellulose ester, for example, those described in paragraph [0178] of JP-A No. 2000-155216 can be employed. The amount of the polymer added is preferably 0.1 to 10% by mass and more preferably 0.1 to 8% by mass with respect to the discotic liquid crystal compound in relation to the orientation of the discotic liquid crystal compound. preferable.

The optically anisotropic layer can be produced by applying a liquid crystal composition to a surface (preferably a rubbing-treated surface of an alignment film) to obtain a desired alignment state and then curing. Various methods such as a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method can be used for coating.
Curing preferably involves a curing reaction such as a polymerization reaction and a crosslinking reaction of the components contained in the liquid crystal composition. For example, it is preferable to cure the liquid crystal composition containing a polymerizable liquid crystal by irradiating light such as ultraviolet rays so that the polymerization reaction proceeds. In this method, it is preferable to add a photopolymerization initiator to the liquid crystal composition.

The optical compensation film used in the present invention preferably has a support that supports the optically anisotropic layer. As the support, glass or a transparent polymer film is preferably used. The support preferably has a transmittance (at wavelengths of 400 nm to 700 nm) of 80% or more and a haze of 2.0% or less.
Examples of the main material of the polymer film used for the support include cellulose acylate (for example, mono-, di- and triacylate of cellulose), norbornene-based polymer and polymethyl methacrylate.
Commercially available polymers known under the trade names of “ARTON (registered trademark)” and “ZEONEX (registered trademark)” may be used. The polymer film can be appropriately adjusted as necessary. Polymers having relatively small birefringence as listed above are preferred because retardation can be easily adjusted and uneven stretching is less likely to occur.

  For optical compensation of the TN liquid crystal cell, the optical compensation film needs to exhibit negative birefringence. Therefore, the birefringence of the polymer film is preferably negative in the optical compensation film. Moreover, even if it is a polymer which is easy to express birefringence like the conventionally known polycarbonate and polysulfone, as described in International Publication No. 00/26705 pamphlet, the birefringence can be developed by modifying the molecule. If it is controlled, it can be used.

As the polymer film, a cellulose acylate film is preferable. The cellulose acylate film raw material cellulose includes cotton linter, kenaf, wood pulp (hardwood pulp, softwood pulp), etc., and any cellulose ester obtained from any raw material cellulose can be used. Also good.
The cellulose acylate can be prepared by esterifying cellulose. The cellulose acylate is preferably a cellulose ester of a carboxylic acid having 2 to 22 carbon atoms in total. The acyl group having 2 to 22 carbon atoms contained in cellulose acylate may be either an aliphatic acyl group or an aromatic acyl group, and is not particularly limited. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, cycloalkyl carbonyl esters, aromatic carbonyl esters, aromatic alkyl carbonyl esters, and the like of cellulose, each of which may further have a substituted group. Examples of these preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, cyclohexanecarbonyl, adamantanecarbonyl, phenylacetyl, benzoyl, naphthylcarbonyl, (meth) acryloyl, and cinnamoyl groups. Among these, more preferred acyl groups are acetyl, propionyl, butanoyl, pentanoyl, hexanoyl, cyclohexanecarbonyl, (meth) acryloyl, phenylacetyl and the like.

  A method for synthesizing cellulose acylate is disclosed in JIII Journal of Technical Disclosure No. 2001-1745 (Japan Society for Invention and Invention Issued on March 15, 2001) p. 9 can be referred to.

  The polymer film is preferably subjected to a surface treatment. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment (saponification treatment), and ultraviolet irradiation treatment. When the polymer film is a cellulose acylate film, it is particularly preferable to perform a saponification treatment.

  The optical compensation film used in the present invention may have an alignment film between the optically anisotropic layer and the support. The alignment film is used for forming an optically anisotropic layer. An alignment film produced by rubbing the surface of a layer made of a polymer such as polyvinyl alcohol is preferred. The rubbing treatment can be appropriately performed using a known method such as a rubbing roll.

As described above, the optical compensation film can be bonded to a polarizer and used as a polarizing plate in the liquid crystal display device of the present invention.
There is no restriction | limiting in particular about the said polarizer. Various polarizers can be used. Optiva Inc. And a polarizer comprising a binder and iodine or a dichroic dye are preferable.
It is preferable that the protective film is also bonded to the surface of the polarizer opposite to the surface on which the optical compensation film is bonded. Examples of the protective film are the same as those of the polymer film that can be used as a support for the optical compensation film.
When laminating the polarizer and each of the optical compensation film and the protective film, an adhesive may be used. For example, a polyvinyl alcohol resin (according to acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) Modified polyvinyl alcohol) and an aqueous boron compound solution can be used as an adhesive. Among these, polyvinyl alcohol resin is preferable. The thickness of the adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and particularly preferably in the range of 0.05 to 5 μm.

In addition, it is preferable to dispose an antireflection layer on the viewing side surface of the polarizing plate used as the viewing side polarizing plate in the liquid crystal display device of the present invention, and the antireflection layer is used to protect the viewing side of the polarizer. You may combine with a layer.
From the viewpoint of suppressing color change due to the viewing angle of the liquid crystal display device, the internal haze of the antireflection layer is preferably 50% or more. Specific examples of these are described in JP-A No. 2001-33783, JP-A No. 2001-343646, and JP-A No. 2002-328228.

(Diffusion plate)
In the liquid crystal display device of the present invention, it is preferable to use a diffusion plate that satisfies the above formula (3). The diffusion plate is generally used as a member of a backlight unit. However, the diffusion plate may be disposed at any position as long as it is between the light source and the backlight side polarizer.
An example of the diffusion plate that can be used in the present invention is a diffusion plate having a light-transmitting resin and a light scattering layer containing particles dispersed in the light-transmitting resin. The diffusing plate may have a translucent substrate that supports the light scattering layer. This diffusing plate exhibits light scattering characteristics that depend on the particle size of the particles contained in the light scattering layer, the refractive index difference between the translucent resin and the particles, the shape of the dispersed particles, and the like. By adjusting these characteristics, it is possible to produce a diffusion plate that satisfies the above formula (3).

Light scattering layer:
The average particle diameter of the particles contained in the light scattering layer is preferably 1.5 μm or less. When the average particle diameter of the particles exceeds 1.5 μm, the wavelength dependency of scattering tends to be lost. On the other hand, when the thickness is less than 0.5 μm, the backscattering property becomes strong and the transmittance becomes low. Therefore, the average particle diameter of the particles is preferably 0.5 to 1.5 μm, and 0.8 to 1.3 μm. More preferably.

  There is no particular limitation on the shape of the particles. Particles of various shapes such as a spherical shape and a needle shape can be used. The inclusion of anisotropically shaped particles is preferable because it exhibits a directional light scattering property. Moreover, since it becomes a light-scattering layer which shows the spectral anisotropic scattering characteristic mentioned later, it is preferable. An aspect ratio can be used as an index of shape anisotropy. It is preferable to contain particles having an aspect ratio of 2 to 20.

  There is no restriction | limiting in particular about the material of the said particle | grain. Any of particles made of an inorganic material, an organic material, and a mixture thereof can be used. Examples of the inorganic material include silicon oxide, aluminum oxide, barium sulfate and the like. Examples of organic materials include acrylic resins, divinylbenzene resins, benzoguanamine resins, styrene resins, melamine resins, acrylic-styrene resins, polycarbonate resins, polyethylene resins, polyvinyl chloride resins, etc. It is. Moreover, fine particles such as a mixed system of two or more of these can be mentioned. It is preferable to use highly transparent particles, and among these, melamine resins, benzoguanamine resins, polymethyl methacrylate resins, and mixed resins and copolymers thereof are preferably used.

The particles contained in the light scattering layer and the translucent resin have different refractive indexes. The difference is preferably 0.03 or more, and more preferably 0.05 or more. The larger the refractive index difference, the stronger the light scattering property. On the other hand, if the refractive index difference is too large, the back scattering property becomes strong and the transmittance decreases. Therefore, the refractive index difference is 0.20 or less. preferable. The material having a large refractive index may be a particle or a translucent resin, but it is preferable that the particle has a large refractive index. Since the refractive index of the translucent resin is generally about 1.5, the refractive index of the particles is preferably larger than 1.5. Examples of such particles include aluminum oxide (1.62), benzoguanamine / formaldehyde condensate (1.66), benzoquaminamine / melamine / formaldehyde condensate (1.66, 1.52), and melamine / formaldehyde condensate ( 1.66), silica / acrylic compound (1.52), methacrylic compound (1.51) and the like. The number in parentheses is the refractive index.
The content of the particles in the light scattering layer is not particularly limited as long as it is an amount that can scatter light and does not impair the transparency of the light scattering layer. The amount is preferably about 70% by mass, and more preferably about 1.0-50% by mass.

  There is no restriction | limiting in particular also about the said translucent resin, It can select from various translucent resin materials. Examples thereof include acrylic resins, epoxy resins, polyvinyl alcohol resins, polyimide resins, vinyl ether resins, and the like. In addition, some resins formed by curing an ultraviolet curable resin material include a translucent resin, and therefore an ultraviolet curable resin material can be used.

The said light-scattering layer can be formed by apply | coating the coating liquid for light-scattering layer formation containing particle | grains and transparent resin to the surface, and making it solidify. Solidification preferably proceeds when the material in the coating solution undergoes a polymerization reaction or a crosslinking reaction. Therefore, it is preferable to add a photopolymerization initiator to the coating solution.
The thickness of the light scattering layer is not particularly limited as long as it does not impair the transparency, and is usually about 0.5 μm to 20 μm, preferably about 1.0 μm to 5 μm, more preferably, It is about 2.0 μm to 5.0 μm

Translucent substrate:
The light scattering layer may be supported by a translucent substrate. There is no restriction | limiting in particular about the material of a translucent board | substrate. It may be a glass substrate or a polymer film. Examples of the polymer film that can be used are the same as the polymer film exemplified as the support film of the optically anisotropic layer.
In addition, the said light-scattering layer may be directly formed on surfaces, such as a protective film of a polarizing plate, for example, In the aspect, the said translucent board | substrate is unnecessary.

Spectral anisotropic scattering film:
In the present invention, it is preferable to use a spectrally anisotropic scattering film as the diffusion plate that satisfies the above-mentioned formula (3). Here, the “spectral anisotropic scattering film” is a light scattering film in which the scattering profile of light in the visible light region exhibits different scattering characteristics depending on the wavelength between two different scattering surfaces. As for the spectral anisotropic scattering film, various modes are exemplified in JP-A No. 2004-341308, and any mode can be used in the present invention. Specifically, an embodiment including at least a part of a one-dimensional diffraction grating or a photonic crystal structure; an embodiment in which shape anisotropic particles are dispersed in a film; and an embodiment having irregularities of shape anisotropy on the surface Can be mentioned.

  Examples of the one-dimensional diffraction grating that can be used in the present invention include P.I. It may be a one-dimensional grid transmission diffraction grating as described on page 58 of Yeh's photorefractive nonlinear optics (Yasuo Tomita and Kenichi Kitayama, published in March 1995). As a method for producing a one-dimensional grid transmission diffraction grating, for example, a method using two-beam interference exposure; a method of exposing ultraviolet rays or visible light to a resist or photopolymer through a grid mask produced by electron beam drawing; a similar method And a method of applying and curing an ultraviolet curable resin or a thermosetting resin on the irregularities of the grid prepared in advance, and a method of peeling the irregularities mechanically by embossing or the like.

  As the photonic crystal that can be used in the present invention, a photonic crystal as described in Shojiro Kawakami's photonic crystal technology and its application (issued by CMC Publishing Co., Ltd., March 2002) should be used. And diffraction can be controlled at multiple different wavelengths and at multiple different directions. Examples of a method for producing a photonic crystal include a method by multi-beam interference exposure using three or more light beams, and a method of densely arranging monodisperse fine particles on a substrate.

  The spectrally anisotropic scattering film may be a film in which shape anisotropic particles having a refractive index different from that of the continuous phase are dispersed in a continuous phase (for example, a polymer phase). The shape anisotropic particles are preferably dispersed in a predetermined arrangement in order for the film to exhibit the above dispersion characteristics. As a method of arranging and dispersing the shape anisotropic particles in the film, for example, as described in JP-A-9-297204, the shape anisotropic particles are dispersed in the film and then stretched and arranged. Method: A method of dispersing spherical particles, liquid, monomer or air bubbles which are different in refractive index from the binder of the film and deformable by an external force in the film, and then stretching and deforming and arranging the particles. In order to promote alignment and deformation, heating or humidification may be performed before or during stretching.

  The spectrally anisotropic scattering film may be a film having surface irregularities having shape anisotropy. As a method for producing the film, a polymer solution in which particles are dispersed is applied on a support to form an irregular layer. A method of forming anisotropic unevenness by stretching after application; A method of forming anisotropic unevenness by applying isotropic unevenness directly on the film by embossing, sandblasting, etc .; A method of applying an ultraviolet curable resin or a thermosetting resin on a concavo-convex surface of a master on which surface concavo-convex has been formed in advance by beam drawing, laser irradiation or the like, a method of peeling after curing; Is mentioned. When anisotropy is expressed by stretching, heating or humidification may be performed before stretching or during stretching in order to promote deformation.

(Colored layer)
In the present invention, a colored layer satisfying the formula (5) can be used. The colored layer is preferably arranged in an optical path from the light emitted from the backlight to the liquid crystal cell. You may form on the surface of one member of a backlight unit, and may form on the surfaces, such as a protective film of a polarizer. Further, the colored layer may be a colored film having a self-supporting property.

  An example of the colored layer is a layer in which the colored domains are arranged in a predetermined pattern in the translucent domain. Another example is a layer in which a plurality of different colored domains are arranged in a predetermined pattern. The arrangement of each color coloring pattern is not particularly limited, and may be any of a stripe type, a mosaic type, a triangle type, a four pixel arrangement type, and the like. As a material for forming the colored layer, materials generally used for color filters can be used. The colored layer can be formed by a general pigment dispersion method, dyeing method, electrodeposition method, printing method, or the like. Moreover, it can form using various patterning techniques.

Hereinafter, the present invention will be described more specifically by way of examples. However, the embodiments of the present invention are not limited to these examples.
[Example 1]
<Production of optical compensation film>
(Preparation of support S-1)
The following composition was put into a mixing tank and stirred while heating to 30 ° C. to dissolve each component to prepare a cellulose acetate solution.
────────────────────────────────────
Cellulose acetate solution composition (parts by mass) Inner layer Outer layer ────────────────────────────────────
Cellulose acetate with an acetylation degree of 60.9% 100 100
Triphenyl phosphate (plasticizer) 7.8 7.8
Biphenyl diphenyl phosphate (plasticizer) 3.9 3.9
Methylene chloride (first solvent) 293 314
Methanol (second solvent) 71 76
1-butanol (third solvent) 1.5 1.6
Silica fine particles (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
0 0.8
The following retardation increasing agent 1.7 0
────────────────────────────────────

  The obtained inner layer dope and outer layer dope were cast on a drum cooled to 0 ° C. using a three-layer co-casting die. The film having a residual solvent amount of 70% by mass was peeled off from the drum, both ends were fixed with a pin tenter, and the film was dried at 80 ° C. while transporting at a draw ratio of 110% in the transport direction, resulting in a residual solvent amount of 10%. By the way, it was dried at 110 ° C. Thereafter, it was dried at 140 ° C. for 30 minutes to produce a cellulose acetate film (outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) having a residual solvent of 0.3 mass%. Optical characteristics of the produced cellulose acetate film S-2 were measured.

  The resulting cellulose acetate film had a width of 1340 mm and a thickness of 80 μm. Re was 6 nm and Rth was 90 nm.

<Preparation of alignment film>
On the saponified support S-1, an alignment film coating solution having the following composition was coated at 28 mL / m ² with a # 16 wire bar coater. The film was dried with warm air of 60 ° C. for 60 seconds and further with warm air of 90 ° C. for 150 seconds to produce an alignment film. The thickness of the alignment film after drying was 1.1 μm.

(Orientation film coating solution composition)

<Orientation treatment>
The support S-1 coated with the alignment film was subjected to a rubbing treatment on the alignment film installation surface so as to be aligned in parallel with the transport direction. The rubbing roll was rotated at 450 rpm.

<Coating of optically anisotropic layer>
The following composition was dissolved in 270 kg of methyl ethyl ketone to prepare a coating solution.
Composition for forming optically anisotropic layer 90.0 parts by mass of liquid crystal compound (1) shown in the following table 10.0 parts by mass of liquid crystal compound (2) shown in the following table 0.8 parts by mass of the following fluoroaliphatic group-containing polymer 1 Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3.0 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.0 parts by mass

It was 2.0 mPa * s when the viscosity at 25 degrees C of the prepared coating liquid was measured with the B-type viscometer (BL type, Tokyo Keiki Co., Ltd. product).
The prepared coating solution was applied to the surface of the alignment film using a # 2.8 wire bar. The coating amount was 4.8 mL / m ² . Then, it heated for 90 second in a 120 degreeC thermostat, and the discotic liquid crystal compound was orientated. Next, using a 160 W / cm high-pressure mercury lamp at 80 ° C., ultraviolet irradiation was performed for 1 minute to advance the crosslinking reaction, and the discotic liquid crystal compound was polymerized to form an optically anisotropic layer.

  As shown in the following table, optical compensation films 1 to 8 were produced in the same manner except that the composition of each component was changed and the conditions at the time of coating were changed. In addition, about the component which is not described in the following table | surface, it is the same as the said composition.

Re (450) and Re (650) were measured for each of the optically anisotropic layers of the optical compensation films 1 to 8, and Re (450) / Re (650) was calculated.
Re (450) / Re (650) of the optically anisotropic layer of the optical compensation film 1 formed using only triphenylene liquid crystal was 1.29.
On the other hand, all of the optically anisotropic layers of the optical compensation films 2 to 8 formed by using the general formula (DI) alone or in combination with the triphenylene liquid crystal have Re (450) / Re (650) of 1.17. It was about.

<Preparation of polarizing plate>
A linearly polarizing film was produced by adsorbing iodine to the stretched polyvinyl alcohol film. Thereafter, a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) was subjected to saponification treatment and attached to one side of the linearly polarizing film using a vinyl alcohol adhesive. Furthermore, on the other surface of this linearly polarizing film, the optical compensation film 2 produced in Example 1 was coated with the back surface of the support S-1 (an optically anisotropic layer was formed using a polyvinyl alcohol-based adhesive). A polarizing plate P-1 was prepared by pasting the linear polarizing film with the non-side surface on the surface side of the linearly polarizing film.

<Production of high wavelength-dependent scattering film>
100 parts by mass of UV curable resin (Desolite Z 7526, manufactured by JSR Corporation, refractive index 1.51) as translucent resin, and benzoguanamine / melamine formaldehyde beads (manufactured by Nippon Shokubai Co., Ltd., spherical particles) as particles And 18 parts by mass of a particle size of 1.0 μm and a refractive index of 1.66) were mixed to prepare 50% solid content with methyl ethyl ketone / acetone (40/60 mass ratio). This solution was coated on a cellulose acetate film (TD-80U, manufactured by Fuji Film Co., Ltd.) so as to have a dry film thickness of 3.0 μm, dried with a solvent, and then an air-cooled metal halide lamp (Igraphics) with 160 W / cm. Co., Ltd.) is used to cure the coating layer by irradiating ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² to form a light scattering layer, and a light scattering film (SF-1). Produced.
The scattering intensity ratio D (450) / D (550) between the wavelength 450 nm and the wavelength 550 nm in the 45 ° direction of this light scattering film was 1.8.
The scattering intensity ratio was measured using a spectroradiometer SR-3 (manufactured by Topcon Corporation).

<Production of TN mode liquid crystal display device>
A diffuser plate and a prism sheet were provided on the LED backlight, and the high wavelength-dependent scattering film film SF-1 of the present invention was stacked thereon to form a backlight unit.
The LED element was selected so that the ratio of peak intensity of B light and G light was P (B) / P (G) = 1.0.
The intensity ratio of light 450 nm to 550 nm, I (450) / I (550), of light incident in the 45 ° direction on the liquid crystal cell of the manufactured liquid crystal display device was 1.5. The incident light intensity ratio was measured using a spectroradiometer SR-3 (manufactured by Topcon Corporation).
The produced polarizing plate P-1 was affixed on both sides of the TN mode liquid crystal cell via an adhesive such that the optically anisotropic layer was on the cell side.

[Example 2]
(Preparation of spectrally anisotropic scattering film SF-2)
Polyvinyl alcohol (PVA 205, manufactured by Kuraray Co., Ltd.) 100 g and alkyl-modified polyvinyl alcohol (MP 203, manufactured by Kuraray Co., Ltd.) 300 g were dissolved in water 1600 g to prepare an aqueous solution W-1 for continuous phase. Further, 100 g of high refractive index monomer MPSMA ([Bis (4-methacryloylthiophenyl) sulfide], manufactured by Sumitomo Seika Co., Ltd.) is mixed with 900 g of the W-1 solution, and this solution is dispersed by ultrasonic dispersion. A coating liquid C-1 was prepared.
This coating solution C-1 was band-cast using a die and dried to a thickness of 100 μm. This film was peeled off from the band, stretched twice in the longitudinal direction at 80 ° C. with a humidity of 60% RH, and directly saponified 80 μm thick cellulose acetate film (TD80U, manufactured by Fuji Film Co., Ltd.) with polyvinyl Alcohol (PVA117, Kuraray Co., Ltd.) 5 mass% aqueous solution was laminated as paste. This film was dried at 120 ° C. to produce a spectrally anisotropic scattering film SF-2.
The scattering intensity ratio D (450) / D (550) between the wavelength 450 nm and the wavelength 550 nm in the 45 ° direction of this spectrally anisotropic scattering film was 1.8.

  A liquid crystal display device was produced in the same manner as in Example 1 except that the spectrally anisotropic scattering film SF-2 was used instead of the high wavelength dispersion scattering film SF-1. In addition, it arrange | positioned so that the extending | stretching direction of SF-2 may turn into the left-right direction.

[Example 3]
Instead of using the high wavelength dispersion / scattering film SF-1, a colored plate having a transmitted light intensity ratio of 450 nm to 550 nm in the 45 ° direction and a wavelength T (450) / T (550) of 1.2 is used instead. A liquid crystal display device was produced in the same manner as in Example 1 except for the arrangement.
The transmitted light intensity ratio was measured with an automatic variable angle photometer GP-200 (Murakami Color Research Laboratory Co., Ltd.).

[Example 4]
The high wavelength dispersion / scattering film SF-1 is not used, and in the emission spectrum of the LED light source, the ratio of peak intensity corresponding to B light and G light in the 45 ° direction, P (B) / P (G) is 1.5. A liquid crystal display device was produced in the same manner as in Example 1 except that the peak intensity was adjusted so that
The peak intensity ratio of B light and G light was measured using a spectroradiometer SR-3 (manufactured by Topcon Corporation).

[Example 5]
A light scattering film was produced using benzoguanamine / melamine formaldehyde beads (Nippon Shokubai Co., Ltd., spherical particles, particle size 1.3 μm, refractive index 1.66) as particles.
The scattering intensity ratio D (450) / D (550) between the wavelength 450 nm and the wavelength 550 nm in the 45 ° direction of the produced light scattering film was 1.5.
A liquid crystal display device was produced in the same manner as in Example 1 except that this light scattering film was used instead of the high wavelength dispersion scattering film SF-1.

[Comparative Example 1]
A liquid crystal display device was produced in the same manner as in Example 1 except that the optical compensation film 1 was used instead of the optical compensation film 2.

[Comparative Example 2]
A liquid crystal display device was produced in the same manner as in Example 1 except that the high wavelength dispersion / scattering film SF-1 was not used.

[Comparative Example 3]
A light scattering film was prepared using benzoguanamine / melamine formaldehyde beads (Nippon Shokubai Co., Ltd., spherical particles, particle size 1.6 μm, refractive index 1.66) as particles.
The scattering intensity ratio, D (450) / D (550), between the wavelength of 450 nm and the wavelength of 550 nm in the 45 ° direction of the produced light scattering film was 1.0.
A liquid crystal display device was produced in the same manner as in Example 1 except that this light scattering film was used instead of the high wavelength dispersion scattering film SF-1.

About each produced liquid crystal display device, the blue tint which arises in the up-down direction at the time of black display, and the yellow tint which arises in the left-right direction at the time of white display were measured with the measuring device (EZ-Contrast160D, ELDIM company make). In the black display, the evaluation was performed by the difference Δv ′ between the front and the most bluish position at the viewing angle Δv ′ = maximum color v′−front color v ′. In the white display, the evaluation was performed based on the difference in color tone Δv ′ = maximum color v′−front color v ′ between the front and the most yellowed position in the viewing angle. When V ′ is −0.05 or less, blue is felt, and when it is +0.05 or more, yellow is felt.
In black display, −0.05 ≦ Δv ′ ≦ 0.00 is preferable, and −0.02 ≦ Δv ′ ≦ 0.00 is more preferable.
In white display, 0.00 ≦ Δv ′ ≦ 0.05 is preferable, and 0.00 ≦ Δv ′ ≦ 0.02 is more preferable.
Further, the front contrast in the normal direction was also measured and evaluated for each liquid crystal display device.

From the results shown in the above table, the liquid crystal of Examples 1 to 5 including the optical compensation film 2 having the optically anisotropic layer satisfying the formula (1) and the light intensity of the incident light satisfying the formula (2). It can be understood that both of the display devices are reduced in both a blue tint generated in the vertical direction during black display and a yellow tint during white display.
In Example 2 using the spectral anisotropic scattering film, the front CR was lower than the liquid crystal display devices of the other examples. In addition, the spectrally anisotropic scattering film is more difficult to produce than other scattering films, and is inferior to the liquid crystal display devices of other examples in terms of production cost.
Even in Example 3 using the colored layer, there was a loss of light due to absorption, and the front CR was lower than the liquid crystal display devices of the other examples.
In Example 4 using the method of adjusting the emission spectrum of the light source, the effect of reducing the left-right yellow tint was slightly inferior to the liquid crystal display devices of the other examples.
An example using a scattering film produced using spherical particles was the best in terms of total performance.

  In addition, it replaced with the optical compensation film 2, and the same result was obtained even if it used the optical compensation films 3-8.

It is a cross-sectional schematic diagram of an example of the liquid crystal display device of this invention. It is the conceptual diagram used for demonstrating the direction which specifies the characteristic of the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 11 Polarizer 12, 13 Supporting film 14, 15 Optical anisotropic layer 16, 17 Polarizer protective film LC Liquid crystal cell F1, F2 Optical compensation film P1, P2 Polarizing plate BL Backlight unit

Claims (10)

A pair of polarizers, a liquid crystal cell disposed between the pair of polarizers, an optically anisotropic layer disposed between each of the pair of polarizers and the liquid crystal cell, and the pair of polarizers Among them, a liquid crystal display device having at least a backlight unit disposed on the outer side of the polarizer on the back side,
The in-plane retardation Re (450) of wavelength 450 nm and the in-plane retardation Re (650) of wavelength 650 nm of the optically anisotropic layer satisfy the following formula (1), and Re (450) / Re (650 ) <1.25 Formula (1)
The light intensity I (450) of incident light with a wavelength of 450 nm and the light intensity I (550) of incident light with a wavelength of 550 nm from the directions of an azimuth angle of 0 ° and a polar angle of 45 ° to the liquid crystal cell are expressed by the following formula (2 ) Satisfying the following conditions:
1.1 <I (450) / I (550) <5.0 ... Formula (2). The liquid crystal display device according to claim 1, wherein the optically anisotropic layer is a layer formed of a liquid crystal composition. The backlight unit includes a diffusing plate, and the scattering intensity D (450) of the emitted light with a wavelength of 450 nm and the scattered intensity D of the emitted light with a wavelength of 550 nm from the directions of the azimuth angle 0 ° and the polar angle 45 ° of the diffusing plate. (550) satisfies following formula (3), The liquid crystal display device of Claim 1 or 2 characterized by the above-mentioned:
1.1 <D (450) / D (550) <5.0 ... Formula (3). The liquid crystal display device according to claim 1, wherein the diffusion plate contains particles having an average particle diameter (diameter) of 1.5 μm or less. The liquid crystal display device according to claim 1, wherein the diffusion plate exhibits spectral anisotropic scattering. In the emission spectrum of the light source provided in the backlight unit, peak intensities P (B) and P (G) corresponding to blue light and green light in the directions of azimuth angle 0 ° and polar angle 45 ° are expressed by the following formula (4). The liquid crystal display device according to claim 1, wherein:
1.1 <P (B) / P (G) <5.0 (4). The full width at half maximum of peaks of blue light, green light, and red light in directions with an azimuth angle of 0 ° and a polar angle of 45 ° in an emission spectrum of a light source provided in the backlight unit is 50 nm or less, respectively. The liquid crystal display device according to any one of 1 to 6. The liquid crystal display device according to claim 1, wherein a light source included in the backlight unit is an LED. The liquid crystal surface device has a colored layer, and the transmittance T (450) of light having a wavelength of 450 nm and the absorbance T (550) of light having a wavelength of 550 nm in the directions of the azimuth angle 0 ° and polar angle 45 ° of the colored layer. Satisfies the following formula (5): A liquid crystal display device according to claim 1, wherein:
T (450) / T (550)> 1.0 (5) The liquid crystal display device according to claim 1, wherein the liquid crystal cell is in a TN mode.

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