JP5538062B2 - Twisted orientation mode liquid crystal display - Google Patents

Description

  The present invention relates to a twisted alignment mode liquid crystal display device with improved contrast in the vertical and horizontal directions of the screen.

It has been proposed to use a twisted or spread O-plate as an optical compensation film of a twisted alignment mode liquid crystal display device such as a TN mode (Patent Document 1).
Also proposed is an optical compensation film containing a positive birefringent material, wherein the material is tilt-aligned with an average tilt angle of 10 ± 5 ° on the optical axis. (Patent Document 2).
Further, an optical compensation film having at least one O-plate, at least one low tilt A plate, and at least one negative C plate has been proposed (Patent Document 3).

  Conventionally, when an optically anisotropic layer or O-plate having a tilt orientation with a low tilt angle is actually combined with a TN mode liquid crystal cell, as shown in the drawings in Patent Documents 2 and 3, these In general, the in-plane slow axis of these members and the optical axis direction of the liquid crystal in the vicinity of the cell substrate disposed near these members are orthogonal to each other.

US Pat. No. 5,619,352 JP 2006-504146 (WO 2004/040340) WO01 / 20392

However, when the present inventor has examined, when an optical compensation film using an O-plate or the like is used in a TN mode liquid crystal display device, a high contrast is obtained in a wide viewing angle range in the horizontal direction of the screen, but in the vertical direction. It was found that the contrast decreased in the oblique direction.
Therefore, an object of the present invention is to provide a twisted alignment mode liquid crystal display device that achieves high contrast over a wide viewing angle in any of the upper, lower, left, and right directions of the screen.

  As a result of various studies by the present inventor, when an optically anisotropic layer using the tilted orientation of a rod-like liquid crystal such as an O-plate is used for optical compensation of a liquid crystal cell of a twisted orientation mode such as a TN mode, the optical The optical axis of the anisotropic layer and the optical axis of the liquid crystal layer are arranged in a relationship different from the conventional one, and the optical characteristics of the other optical anisotropic layers to be used in combination are set within a predetermined range, so that the horizontal direction of the screen Not only that, but also in the vertical direction of the screen, it has been found that high contrast can be achieved in a wide viewing angle range, and based on this finding, further studies have been made and the present invention has been completed.

That is, the means for solving the above problems are as follows.
[1] First and second polarizing films disposed with their absorption axes orthogonal to each other,
First and second cell substrates disposed between the first and second polarizing films (however, the first cell substrate is disposed closer to the first polarizing film, and the second And a liquid crystal cell in a twisted alignment mode having at least a liquid crystal layer disposed therebetween, and the first polarizing film and the liquid crystal. First and second optics having at least three optically anisotropic layers, optically anisotropic layers A, B, and C, respectively, between the cells and between the second polarizing film and the liquid crystal cell. A liquid crystal display device having an anisotropic laminate,
The order of the arrangement of the first optically anisotropic layers A, B, and C in each of the first and second optically anisotropic laminates is symmetric about the liquid crystal cell,
The optically anisotropic layer A contains a rod-like liquid crystal fixed in an inclined alignment state, and the in-plane retardation at a wavelength of 550 nm is 0 to 200 nm,
The sum of in-plane retardations of the optically anisotropic layers B and C is 0 to 300 nm, the in-plane slow axis of the optically anisotropic layer B in the first optically anisotropic laminate, and the The absorption axis with the first polarizing film is parallel or orthogonal, and the in-plane slow axis of the optically anisotropic layer B in the second optically anisotropic laminate and the second polarizing film The absorption axes of are parallel or orthogonal;
The axes obtained by projecting the optical axis of the optically anisotropic layer A in the first optically anisotropic laminated body and the optical axis of the first cell substrate of the liquid crystal layer in the same plane are antiparallel to each other. And the axes obtained by projecting the optical axis of the optically anisotropic layer A in the second optically anisotropic laminate and the optical axis of the second cell substrate of the liquid crystal layer in the same plane are mutually A twisted alignment mode liquid crystal display device that is antiparallel or orthogonal.
[2] From the liquid crystal cell side, the optically anisotropic layer A, the optically anisotropic layer B, and the optically anisotropic layer C are arranged in this order, and the optically different layers in the second optically anisotropic laminate are arranged. [1] The twisted alignment mode liquid crystal display device according to [1], wherein the optical axis of the isotropic layer A and the optical axis of the liquid crystal layer on the second cell substrate are antiparallel to each other.
[3] The twisted alignment mode liquid crystal display device according to [2], wherein an average tilt angle of the rod-like liquid crystal of the optically anisotropic layer A is 10 to 85 °.
[4] The twisted alignment mode liquid crystal display device according to [2] or [3], wherein the in-plane retardation of the optically anisotropic layer A is 0 to 150 nm.
[5] The in-plane retardation of the optically anisotropic layer C is 0 to 300 nm, the retardation in the thickness direction is −200 to 300 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 300 nm. A twisted alignment mode liquid crystal display device according to any one of [2] to [4].
[6] The optically anisotropic layer B contains a rod-like liquid crystal fixed in an inclined orientation state with an average inclination angle of 30 ° or less or 75 to 90 °, and the in-plane retardation is 0 to 200 nm. The twisted alignment mode liquid crystal display device according to any one of [5].
[7] The twisted alignment mode liquid crystal according to any one of [2] to [5], wherein the optically anisotropic layer B is a polymer film, the in-plane retardation is 0 to 300 nm, and the retardation in the thickness direction is 0 to 250 nm. Display device.

[8] From the liquid crystal cell side, the optically anisotropic layer A, the optically anisotropic layer B, and the optically anisotropic layer C are arranged in this order, and the optical anisotropy in the second optically anisotropic laminate is provided. [1] The twisted alignment mode liquid crystal display device according to [1], wherein an axis obtained by projecting the optical axis of the conductive layer A and the optical axis of the liquid crystal layer on the second cell substrate in the same plane is orthogonal to each other.
[9] The twisted alignment mode liquid crystal display device according to [8], wherein an average tilt angle of the rod-like liquid crystal of the optically anisotropic layer A is 5 to 60 °.
[10] The twisted alignment mode liquid crystal display device according to [8] or [9], wherein the in-plane retardation of the optically anisotropic layer A is 0 to 150 nm.
[11] The in-plane retardation of the optically anisotropic layer C is 0 to 300 nm, the retardation in the thickness direction is 0 to 250 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 250 nm. The twisted alignment mode liquid crystal display device according to any one of [8] to [10].
[12] The optically anisotropic layer B contains a rod-like liquid crystal fixed in an inclined orientation state with an average inclination angle of 30 ° or less or 75 to 90 °, and the in-plane retardation is 0 to 160 nm. [11] The twisted alignment mode liquid crystal display device according to any one of [11].
[13] The twisted alignment mode liquid crystal according to any one of [8] to [11], wherein the optically anisotropic layer B is a polymer film, the in-plane retardation is 0 to 250 nm, and the retardation in the thickness direction is 0 to 250 nm. Display device.

[14] From the liquid crystal cell side, the optically anisotropic layer B, the optically anisotropic layer A, and the optically anisotropic layer C are arranged in this order, and the optical anisotropic layer in the second optically anisotropic laminate The twisted alignment mode liquid crystal display device according to [1], wherein the optical axis of the optical layer A and the optical axis of the liquid crystal layer on the second substrate projected in the same plane are antiparallel to each other.
[15] The twisted alignment mode liquid crystal display device according to [14], wherein an average tilt angle of the rod-like liquid crystal of the optically anisotropic layer A is 10 to 85 °.
[16] The twisted alignment mode liquid crystal display device according to [14] or [15], wherein the in-plane retardation of the optically anisotropic layer A is 0 to 150 nm.
[17] The in-plane retardation of the optically anisotropic layer C is 0 to 300 nm, the retardation in the thickness direction is −200 to 300 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 250 nm. The liquid crystal display device according to any one of [14] to [16].
[18] The optically anisotropic layer B contains a rod-like liquid crystal fixed in an inclined orientation state with an average inclination angle of 30 ° or less or 75 to 90 °, and the in-plane retardation is 0 to 200 nm. [17] The twisted alignment mode liquid crystal display device according to any one of [17].
[19] The twisted alignment mode liquid crystal according to any one of [14] to [17], wherein the optically anisotropic layer B is a polymer film, the in-plane retardation is 0 to 250 nm, and the retardation in the thickness direction is 0 to 250 nm. Display device.
[20] The optically anisotropic layer C comprises a film containing at least one selected from cyclic olefin copolymers, cellulose acylates, polyesters, polycarbonates, and acrylates. 5], [11], or [17].
[21] The twisted alignment mode liquid crystal display device according to any one of [5], [11], and [17], wherein the optically anisotropic layer C is a stretched film.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device of the twist orientation mode which achieves high contrast over a wide viewing angle in any direction of the upper, lower, left, and right sides of the screen can be provided.

1 is an exploded perspective view showing a first embodiment of a liquid crystal display device of the present invention. It is a conceptual diagram which shows an example of the relationship of the optical axis of each layer of the liquid crystal display device of 1st Embodiment. It is the conceptual diagram used in order to demonstrate the relationship of "anti-parallel". It is a disassembled perspective view which shows 2nd Embodiment of the liquid crystal display device of this invention. It is a conceptual diagram which shows an example of the relationship of the optical axis of each layer of the liquid crystal display device of 2nd Embodiment. It is a disassembled perspective view which shows 3rd Embodiment of the liquid crystal display device of this invention. It is a perspective view which shows an example of the relationship of the optical axis of each layer of the liquid crystal display device of 3rd Embodiment. It is a disassembled perspective view which shows 4th Embodiment of the liquid crystal display device of this invention. It is a perspective view which shows an example of the relationship of the optical axis of each layer of the liquid crystal display device of 4th Embodiment.

Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the present specification, in this specification, Re (λ) and Rth (λ) respectively represent in-plane retardation (unit: nm) and retardation in thickness direction (unit: nm) at wavelength λ. Represent. 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), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotation axis) (if there is no slow axis, any in-plane film surface) 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 value of the average refractive index, and the input film thickness value.

In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
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及び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 orthogonal to nx in the plane, and nz represents the refractive index in the direction orthogonal 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. In each of the 10 degree steps, light of wavelength λ nm is incident from the inclined direction 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 Calculated by WR.

In the above measurement, as the assumed value of the average refractive index, the values of Polymer Handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. 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).
The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.
In the present specification, when the measurement wavelength is not particularly described for Re, Rth, and refractive index, the measurement wavelength is 550 nm.

Hereinafter, several embodiments of the twisted alignment mode liquid crystal display device of the present invention will be described with reference to the drawings. In the following description, the upper side of the drawing is described as the display surface side and the lower side of the drawing is described as the backlight side, but the upper and lower sides may be reversed.
FIG. 1 shows an exploded perspective view of a first embodiment of the liquid crystal display device of the present invention. A liquid crystal display device LCD1 shown in FIG. 1 includes a first polarizer 4 and a second polarizer 5, and a TN mode liquid crystal cell 10 therebetween. Between the liquid crystal cell 10 and the first polarizer 4, and between the liquid crystal cell 10 and the second polarizer 5, the optically anisotropic layer A (6, 6 ′) and the optically anisotropic layer B (7, 7 ') and the first and second optically anisotropic laminates 12, 12' including the optically anisotropic layer C (8, 8 ') are disposed. In the first and second optically anisotropic laminates 12 and 12 ′, each optically anisotropic layer is centered on the liquid crystal cell 10, and the optically anisotropic layer A (6, 6 ′) is optically anisotropic. The layers B (7, 7 ′) and the optically anisotropic layer C (8, 8 ′) are arranged in this order, that is, they are symmetrically arranged with the liquid crystal cell 10 as the center. The first and second polarizers 4 and 5 are arranged with their absorption axes 4a (or 4b) and 5a (or 5b) orthogonal to each other.

  The liquid crystal cell 10 includes a first substrate 2 and a second substrate 3 and a liquid crystal layer 1 disposed therebetween. The alignment films (not shown) formed on the inner surfaces of the first substrate 2 and the second substrate 3 are rubbed along directions 2b and 3b perpendicular to each other, and when no drive voltage is applied, The liquid crystal molecules 1a in the liquid crystal layer 1 are twisted and aligned at about 90 °. Therefore, when no driving voltage is applied, the linearly polarized light that has passed through the second polarizer 5 passes through the liquid crystal layer 1 and thus the polarization axis rotates, so that it can pass through the first polarizer 4 and the LCD 10 is white. Display status. On the other hand, when the driving voltage is applied, the twisted alignment of the liquid crystal molecules 1a at the center in the liquid crystal layer 1 is eliminated, so that the linearly polarized light that has passed through the second polarizer 5 has passed through the liquid crystal layer 1, Blocked by the absorption axis 4a (or 4b) of the first polarizer 4, the LCD 10 is in a black display state. However, the liquid crystal molecules 2a and 2b in the vicinity of the first and second substrates 2 and 3 in the liquid crystal layer 1 are inclined at a predetermined tilt angle with respect to the substrate surface in both black display and white display. Since the liquid crystal layer 1 is obliquely oriented in 2c and 3c, birefringence occurs in the oblique direction, causing a decrease in contrast in the oblique direction. The first and second optically anisotropic laminates 12 and 12 ′ are formed by the tilt alignment of the liquid crystal molecules 2a and 2b in the vicinity of the first and second substrates 2 and 3 in the liquid crystal layer 1. It acts to optically compensate for refraction.

  In the LCD 1 of the present embodiment, the optical compensation includes the optical anisotropic layer A (6, 6 ′), the optical anisotropic layer B (7, 7 ′), and the optical anisotropic layer C (8, 8). The feature is that three optically anisotropic layers of ') are used. The optically anisotropic layer A (6, 6 ') is an optically anisotropic layer having Re (550) of 0 to 200 nm, containing rod-like liquid crystals 6a and 6'a fixed in a tilted alignment state. It has in-plane slow axes 6b and 6′b determined by the orientation, respectively. The optically anisotropic layer B (7, 7 ′) and the optically anisotropic layer C (8, 8 ′) have a total in-plane retardation of 0 to 300 nm. There are no particular restrictions. The optically anisotropic layer B (7, 7 ') has an in-plane slow axis (7a, 7'a) due to the orientation of liquid crystal molecules or polymers contained therein, and the direction thereof is the first polarized light. It is parallel or orthogonal to the absorption axis 4 a of the film 4 and is parallel or orthogonal to the absorption axis 5 a of the second polarizing film 5. The optically anisotropic layer C (8, 8 ′) may have an in-plane slow axis (8a, 8′a) or an in-plane slow axis depending on the orientation of liquid crystal molecules or polymers contained therein. It may be an optically anisotropic layer that does not have a phase axis and functions as a C plate or the like.

  Further, in the LCD 1 of the present embodiment, the optical axis of the optically anisotropic layer A (6, 6 ′) and the optical axis of the liquid crystal layer in the liquid crystal cell substrate (2, 3) disposed closer to each other Is characterized by being antiparallel. For example, Patent Documents 1 to 3 described above propose using three or more optically anisotropic layers in a TN mode liquid crystal display device, but the configuration is not specifically disclosed. As a result of intensive studies by the present inventor, as shown in FIG. 4A of Patent Document 2, the optical axis of the optically anisotropic layer A containing the rod-like liquid crystal fixed in the tilted alignment state is closer to the layer. When arranged perpendicular to the optical axis of the liquid crystal layer in the arranged liquid crystal cell substrate, the contrast in the oblique direction in the horizontal direction of the screen (the 0-180 ° azimuth in the coordinates described below in FIG. 1) can be improved. It has been found that the contrast in the diagonal direction in the vertical direction of the screen (90-270 ° azimuth in the coordinates described in the lower part of FIG. 1) is not yet satisfactory. Further investigation based on this finding surprisingly found that the optical axis of the optically anisotropic layer A (6, 6 ′) and the liquid crystal cell substrate (2, 3) disposed closer to each other. The optical axis of the liquid crystal layer is arranged antiparallel, and the optically anisotropic layer A (6, 6 ′), the optically anisotropic layer B (7, 7 ′), and the optically anisotropic layer C (8, It has been found that by adjusting Re of the three optically anisotropic layers in 8 ′) within the above range, not only the horizontal direction of the screen but also the contrast in the diagonal direction in the vertical direction of the screen is remarkably improved.

  FIG. 2 is a conceptual diagram showing the relationship among the layers that achieve the above-described action. In an example of the LCD 1, as shown in FIG. 2, the absorption axis 4a of the first polarizer 4 has a 45 ° -225 ° azimuth, the absorption axis 5a of the second polarizer 5 has a 135 ° -315 ° azimuth, The rubbing orientation 2b of the alignment film formed on the inner surface of the cell substrate 2 is 45 ° orientation, and the rubbing orientation 3b of the second cell substrate 3 is 135 ° orientation. Further, in the first optically anisotropic laminates 12 and 12 ′, the in-plane slow axis (7a, 7′a) of the optically anisotropic layer B (7, 7 ′) is 45 ° -225 ° and The 135 ° -315 ° azimuth and the in-plane slow axes (8a, 8a ′) of the optically anisotropic layer C (8, 8 ′) are 135 ° -315 ° and 45 ° -225 ° azimuth, respectively. However, the in-plane slow axis of the optically anisotropic layer B (7, 7 ′) may be the orientations indicated by 7b and 7′b in FIG. 1, that is, 135 ° to 315 ° and 45 ° -225 ° azimuth may be used, and the in-plane slow axis of the optically anisotropic layer C (8, 8 ′) is the azimuth indicated by 8b and 8′b in FIG. Or 45 ° -225 ° and 135 ° -315 ° orientations. Further, either one or both may be an optically anisotropic layer having no in-plane slow axis. As for the absorption axis orientations of the first and second polarizers 4 and 5, the orientations indicated by 4b and 5b in FIG. 1, that is, the absorption axes 4b of the first polarizer 4 are respectively 135 ° to 315 ° orientations. The absorption axis 5b of the second polarizer 5 may be in the 45 ° -225 ° azimuth.

In the LCD 1 of the present embodiment, the tilt direction of the rod-like liquid crystal molecules of the optically anisotropic layer 2 (6, 6 ′) and the liquid crystal cell substrate (2, 3) in the liquid crystal cell substrate (2, 3) disposed closer to each other. The liquid crystal molecules (2a, 3a) are characterized in that the tilt direction is antiparallel. Here, the inclination azimuth and anti-parallel will be described with reference to FIG.
Here, the optically anisotropic layer 1 (7) and the substrate (2) are defined as a virtual plane P1, and the optically anisotropic layer 1 (8) and the substrate (3) are defined as a virtual plane P2. The liquid crystal molecules (6a, 6′a) in the optically anisotropic layer 2 and the liquid crystal molecules (2a, 3a) in the vicinity of the substrate are respectively inclined at angles (6c, 6′c and 2c) with respect to the virtual planes P1, P2. , 3c). Here, the major axis direction of the tilted molecule is defined as the tilt axis (6d, 6′d and 2d, 3d) as shown in FIG. The orientation obtained by projecting the tilt axes (6d, 6′d and 2d, 3d) onto the virtual planes P1, P2 is defined as tilt orientations (6e, 6′e and 2e, 3e) as shown in FIG. When the liquid crystal of the optically anisotropic layer 2 is aligned by rubbing, the rubbing direction and the tilt direction are the same. Similarly, when the liquid crystal molecules in the liquid crystal cell are aligned by rubbing, the rubbing direction and the tilt direction are the same.
The tilt direction (6e, 6'e) of the optically anisotropic layer 2 and the tilt direction (2e, 3e) of the liquid crystal in the vicinity of the cell substrate are parallel but opposite to each other. These relationships are defined as antiparallel.
There are various methods for aligning rod-like liquid crystal molecules in the optically anisotropic layer 2 (6, 6 ′), such as a method of aligning by applying light or a magnetic field in addition to rubbing, and a method of applying an alignment regulating force from the alignment film side. However, the tilt direction can be determined based on FIG. 2 by a method other than rubbing.
Here, the tilt direction (6e, 6'e) of the optically anisotropic layer 2 (6, 6 ') is actually an angle from the normal direction in the above-mentioned KOBRA 21ADH (manufactured by Oji Scientific Instruments). It is possible to detect by measuring the retardation value in the direction inclined by θ.
Further, the tilt direction of the liquid crystal in the vicinity of the cell substrate can be measured by OPTIPRO (manufactured by Shintech Co., Ltd.).

In this embodiment, it is preferable that the rod-like liquid crystal in the optically anisotropic layer A (6, 6 ′) is fixed in an inclined orientation state having an average inclination angle of 10 to 85 °, and an average inclination angle of 20 to 75 °. More preferably, it is fixed in the inclined orientation state.
In addition, Re of the optically anisotropic layer A (6, 6 ′) is preferably 0 to 150 nm, and more preferably 0 to 100 nm.

  In the present embodiment, as described above, the optical anisotropic layer B (7, 7 ') and the optical anisotropic layer C (8, 8') have a total in-plane retardation of 0 to 300 nm. In a preferred combination example, the in-plane retardation of the optically anisotropic layer C (8, 8 ′) is 0 to 300 nm, the retardation in the thickness direction is −200 to 300 nm, and the optically anisotropic layer B (7 7 ′) is an in-plane retardation of 0 to 250 nm. In a more preferable combination example, the in-plane retardation of the optically anisotropic layer C (8, 8 ′) is 0 to 200 nm, the retardation in the thickness direction is 0 to 250 nm, and the optically anisotropic layer B (7 7 ′) in-plane retardation is 0 to 200 nm.

  In this embodiment, the optically anisotropic layer B (7, 7 ′) is an optically anisotropic layer made of a birefringent polymer film, even if it is an optically anisotropic layer made of a liquid crystal composition. Also good. For example, the optically anisotropic layer B (7, 7 ') contains an optical anisotropy containing a rod-like liquid crystal fixed in a horizontal alignment or an inclined alignment state with an average inclination angle of 30 ° or less or 75 to 90 °. A layer is preferred. For example, the birefringence in which the optically anisotropic layer B (7, 7 ′) has Re of 0 to 250 nm (more preferably 0 to 150 nm) and Rth of 0 to 250 nm (more preferably 0 to 150 nm). A conductive polymer film is also preferable.

FIG. 4 is an exploded perspective view of the liquid crystal display device according to the second embodiment of the present invention. 4, the same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
The liquid crystal display device LCD2 of the embodiment shown in FIG. 4 has a first polarizer 4 and a second polarizer 5, and a TN mode liquid crystal cell 10 therebetween. Between the liquid crystal cell 10 and the first polarizer 4, and between the liquid crystal cell 10 and the second polarizer 5, the optically anisotropic layer A (6, 6 ″) and the optically anisotropic layer B (7, 7 ′), and first and second optically anisotropic laminates 12, 12 ″ including the optically anisotropic layer C (8, 8 ′) are disposed. In the first and second optically anisotropic laminates 12 and 12 ″, each optically anisotropic layer has an optically anisotropic layer A (6, 6 ″) and an optically anisotropic layer around the liquid crystal cell 10. The layers B (7, 7 ′) and the optically anisotropic layer C (8, 8 ′) are arranged in this order, that is, they are symmetrically arranged with the liquid crystal cell 10 as the center.

  In the LCD 1, as shown in FIGS. 1 and 2, the rubbing treatment direction 6′b used for the alignment of the rod-like liquid crystal 6′a in the lower optical anisotropic layer A (6 ′) and the second cell The rubbing treatment direction 3b of the alignment film (not shown) formed on the inner surface of the substrate 3 has the same orientation (135 ° -315 ° orientation). In the LCD 2, as shown in FIGS. A rubbing treatment direction 6 ″ b used for alignment of the rod-like liquid crystal 6 ″ a in the optically anisotropic layer A (6 ″) and an alignment film (not shown) formed on the inner surface of the second cell substrate 3 The rubbing direction 3b is different in that it is an orthogonal orientation (the former orientation is 45 ° -225 ° orientation and the latter orientation is 135 ° -315 ° orientation), but the LCD 2 is the same as the LCD 1 The optical axis 6d of the upper optically anisotropic layer A (6) and the optical axis 2 of the first cell substrate 2 Since the axes 6e and 2e projected onto the same plane P1 are antiparallel to each other as shown in FIG. 3, the contrast in the oblique direction not only in the horizontal direction of the screen but also in the vertical direction of the screen is improved as in the LCD 1. Has been.

FIG. 6 is an exploded perspective view of the liquid crystal display device according to the third embodiment of the present invention. In FIG. 6, the same members as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.
A liquid crystal display device LCD3 shown in FIG. 6 includes a first polarizer 4 and a second polarizer 5, and a TN mode liquid crystal cell 10 therebetween. Between the liquid crystal cell 10 and the first polarizer 4, and between the liquid crystal cell 10 and the second polarizer 5, the optically anisotropic layer A (6 ′ ″, 6 ′) and the optically anisotropic layer B are respectively provided. (7, 7 ') and the first and second optically anisotropic laminates 12''', 12 'including the optically anisotropic layer C (8, 8') are disposed. In the first and second optically anisotropic laminates 12 ′ ″ and 12 ′, each optically anisotropic layer is centered on the liquid crystal cell 10 and the optically anisotropic layer A (6 ′ ″, 6 ′). '), The optically anisotropic layer B (7, 7'), and the optically anisotropic layer C (8, 8 ') are arranged in this order, that is, symmetrically arranged around the liquid crystal cell 10. ing.

  In the LCD 1, as shown in FIGS. 1 and 2, the rubbing treatment direction 6b used for the alignment of the rod-like liquid crystal 6a in the upper optical anisotropic layer A (6) and the inner surface of the first cell substrate 2 are formed. The direction 2b of the rubbing treatment of the alignment film (not shown) is the same orientation (45 ° -225 ° orientation), but in the LCD 3, as shown in FIGS. 6 and 7, the upper optical anisotropic layer A ( 6 ″ ′) of the rubbing treatment 6 ′ ″ b used for the alignment of the rod-like liquid crystal 6 ′ ″ a and the alignment film (not shown) formed on the inner surface of the first cell substrate 2. The rubbing direction 2b is different in that it is orthogonal (the former orientation is 135 ° -315 ° orientation and the latter orientation is 45 ° -225 ° orientation). However, in the LCD 3, as in the LCD 1, the axis 6′e obtained by projecting the optical axis 6′d of the lower optical anisotropic layer A (6 ′) and the optical axis 3d of the second cell substrate 3 on the same plane P2. 3e are antiparallel to each other as shown in FIG. 3, so that the contrast in the oblique direction not only in the horizontal direction of the screen but also in the vertical direction of the screen is improved as in the LCD 1.

In the embodiment shown in FIGS. 4 and 6, the rod-like liquid crystal in the optically anisotropic layer A (6 and 6 ″ or 6 ′ ″ and 6 ′) is fixed in an inclined alignment state with an average inclination angle of 5 to 60 °. It is preferable to be fixed in an inclined orientation state with an average inclination angle of 5 to 40 °.
The Re of the optically anisotropic layer A (6 and 6 ″ or 6 ′ ″ and 6 ′) is preferably 0 to 150 nm.

  In the embodiment shown in FIGS. 4 and 6, as in the embodiment shown in FIG. 1, the optically anisotropic layer B (7, 7 ′) and the optically anisotropic layer C (8, 8 ′) The sum of the in-plane retardation is 0 to 300 nm. Particularly preferred combination examples in the present embodiment include an in-plane retardation of the optically anisotropic layer C (8, 8 ′) of 0 to 300 nm, a retardation in the thickness direction of 0 to 250 nm, and an optical anisotropy. The in-plane retardation of the layer B (7, 7 ′) is 0 to 250 nm. In a more preferable combination example, the in-plane retardation of the optically anisotropic layer C (8, 8 ′) is 0 to 200 nm, the retardation in the thickness direction is 0 to 200 nm, and the optically anisotropic layer B (7 , 7 ′) in-plane retardation is 0 to 150 nm.

  4 and 6, the optically anisotropic layer B (7, 7 ') is an optically anisotropic layer made of a birefringent polymer film, even if it is an optically anisotropic layer made of a liquid crystal composition. It may be an isotropic layer. For example, the optically anisotropic layer B (7, 7 ′) is an optically anisotropic layer containing rod-like liquid crystals fixed in an inclined orientation state with an average inclination angle of 30 ° or less or 75 to 90 °. Is preferred. For example, the birefringence in which the optically anisotropic layer B (7, 7 ′) has Re of 0 to 250 nm (more preferably 0 to 200 nm) and Rth of 0 to 250 nm (more preferably 0 to 200 nm). A conductive polymer film is also preferable.

FIG. 8 is an exploded perspective view of the liquid crystal display device according to the fourth embodiment of the present invention. In FIG. 8, the same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
A liquid crystal display device LCD4 shown in FIG. 8 includes a first polarizer 4 and a second polarizer 5, and a TN mode liquid crystal cell 10 therebetween. Between the liquid crystal cell 10 and the first polarizer 4, and between the liquid crystal cell 10 and the second polarizer 5, the optically anisotropic layer B (7, 7 ') and the optically anisotropic layer A (6, 6 ′), and first and second optically anisotropic laminates 14 and 14 ′ including the optically anisotropic layer C (8, 8 ′) are disposed. In the first and second optically anisotropic laminates 14 and 14 ′, each optically anisotropic layer has an optically anisotropic layer B (7, 7 ′) and an optically anisotropic layer around the liquid crystal cell 10. The layers A (6, 6 ′) and the optically anisotropic layer C (8, 8 ′) are arranged in this order, that is, they are symmetrically arranged with the liquid crystal cell 10 as the center.

  In the LCD 1, as shown in FIG. 1, the optically anisotropic layer A (6, 6 ′) is disposed at a position closest to the liquid crystal cell 10, but in the liquid crystal display device LCD4 of the present embodiment, as shown in FIG. As shown, the positions of the optically anisotropic layer B (7, 7 ′) and the optically anisotropic layer A (6, 6 ′) are reversed, and the optically anisotropic layer B (7, 7 ′) is a liquid crystal cell. It is arranged at a position closest to 10. Other than that, the relationship of the optical axes of the respective layers is the same as that of FIG. 2, as shown in FIG. That is, in the LCD 1, a rubbing treatment direction 6 b used for alignment of the rod-like liquid crystal 6 a in the optically anisotropic layer A (6) and an alignment film (not shown) formed on the inner surface of the first cell substrate 2. The direction 2b of the rubbing treatment is the same orientation (45 ° -225 ° orientation), and the rubbing treatment direction 6 used for the orientation of the rod-like liquid crystal 6′a in the optically anisotropic layer A (6 ′). 'b and the direction 3b of the rubbing treatment of the alignment film (not shown) formed on the inner surface of the second cell substrate 3 have the same azimuth (135 ° -315 ° azimuth) and are the same as each other. Further, in the LCD 4 as well, the rubbing treatment direction 6 b used for the alignment of the rod-like liquid crystal 6 a in the optically anisotropic layer A (6) and the alignment film (not shown) formed on the inner surface of the first cell substrate 2. ) In the same direction (45 ° -225 ° azimuth) And an alignment film formed on the inner surface of the second cell substrate 3 and a rubbing treatment direction 6′b used for alignment of the rod-like liquid crystal 6′a in the optically anisotropic layer A (6 ′). The rubbing process directions 3b (not shown) have the same orientation (135 ° -315 ° orientation), and are the same. Accordingly, like the LCD 1, the optical axis 6d of the upper optically anisotropic layer A (6) and the axes 6e and 2e obtained by projecting the optical axis 2d of the first cell substrate 2 on the same plane P1, and the lower optical anisotropic The axes 6′e and 3e obtained by projecting the optical axis 6′d of the conductive layer A (6 ′) and the optical axis 3d of the second cell substrate 3 on the same plane P2 are antiparallel to each other as shown in FIG. Therefore, similar to the LCD 1, not only the horizontal direction of the screen but also the contrast in the diagonal direction in the vertical direction of the screen is improved.

In this embodiment shown in FIG. 8, it is preferable that the rod-like liquid crystal in the optically anisotropic layer A (6, 6 ′) is fixed in an inclined orientation state with an average inclination angle of 10 to 85 °, and the average inclination angle is More preferably, it is fixed in an inclined orientation state of 20 to 75 °.
In addition, Re of the optically anisotropic layer A (6, 6 ′) is preferably 0 to 150 nm, and more preferably 0 to 100 nm.

  In the present embodiment shown in FIG. 8, as in the embodiment shown in FIG. 1, the optically anisotropic layer B (7, 7 ′) and the optically anisotropic layer C (8, 8 ′) have in-plane retardation. Is 0 to 300 nm. In a preferred combination example, the in-plane retardation of the optically anisotropic layer C (8, 8 ′) is 0 to 300 nm, the retardation in the thickness direction is −200 to 300 nm, and the optically anisotropic layer B (7 7 ′) is an in-plane retardation of 0 to 250 nm. In a more preferable combination example, the in-plane retardation of the optically anisotropic layer C (8, 8 ′) is 0 to 200 nm, the retardation in the thickness direction is 0 to 250 nm, and the optically anisotropic layer B (7 7 ′) in-plane retardation is 0 to 200 nm.

  In this embodiment, the optically anisotropic layer B (7, 7 ′) is an optically anisotropic layer made of a birefringent polymer film, even if it is an optically anisotropic layer made of a liquid crystal composition. Also good. For example, the optically anisotropic layer B (7, 7 ′) is an optically anisotropic layer containing a rod-like liquid crystal fixed in a horizontal orientation or an inclined orientation state with an average inclination angle of 30 ° or less or 75 to 90 °. Is preferred. For example, the optically anisotropic layer B (7, 7 ′) has a birefringence in which Re is 0 to 250 nm (more preferably 0 to 200 nm) and Rth is 0 to 250 nm (more preferably 0 to 200 nm). A conductive polymer film is also preferable.

In addition, it is common that a polarizer has a protective film on the surface and the back surface. In the above description, the protective film on the outer side of the first and second polarizers 4 and 5 is omitted. Of course, the protective film may be provided on the outer side. In an embodiment in which the optically anisotropic layer C is a polymer film, the optically anisotropic layer (8, 8 ′) can be used as a protective film for the first and second polarizers 4 and 5.
In the above description, an embodiment in which the first and second optically anisotropic laminates are each composed of three layers of optically anisotropic layers A, B, and C has been described. Layers may be included. However, in the embodiment including four or more layers, it is preferable to adjust the sum of the in-plane retardations of the optical anisotropic layers other than the optical anisotropic layer A to 0 to 300 nm. In addition, the first and second optically anisotropic laminates including three or more optically anisotropic layers may be incorporated into a liquid crystal display device as an integrated member by laminating all or a part thereof, and When each optically anisotropic layer is a self-supporting member, it can also be incorporated as an independent member. However, since the optically anisotropic layer A is a layer made of a rod-like liquid crystal composition, it is usually not self-supporting and will be accompanied by a support for supporting the layer such as a polymer film. The support may be an optically anisotropic layer B and / or an optically anisotropic layer C.
The optically anisotropic layers A, B, and C may be disposed on one side of the liquid crystal display device. At this time, a polymer film is preferably disposed on the surface of the other liquid crystal display device, and the polymer film is preferably an optically anisotropic layer.

In the above figure, the electrode layer, the alignment film, the color filter layer and the like disposed in the liquid crystal cell are omitted, but the liquid crystal display device of the present invention is a general liquid crystal display including these layers. Needless to say, it includes components of the device.
Further, the present invention has an effect of improving the contrast in the diagonal direction of the screen horizontal direction and the vertical direction in any of the liquid crystal display devices using the twisted alignment mode such as the TN mode, the ECB mode, and the OCB mode. In particular, it is effective in an embodiment of a TN mode liquid crystal display device in which the average tilt angle during black display is about 60 to 80 °.

Next, materials that can be used for manufacturing the optically anisotropic layers A, B, and C used in the liquid crystal display device of the present invention, a manufacturing method, and the like will be described in detail.
(Optically anisotropic layer A)
The liquid crystal display device of the present invention contains a rod-like liquid crystal fixed in an inclined alignment state, and has an in-plane retardation at a wavelength of 550 nm of 0 to 200 nm (preferably 0 to 150 nm, more preferably 0 to 100 nm). Has an anisotropic layer.
Here, in the optically anisotropic layer containing the rod-like liquid crystal fixed in the alignment state, the tilt angle (also referred to as “tilt angle” on one surface of the optically anisotropic layer. The physical target axis of the rod-like liquid crystal molecule. It is difficult to directly and accurately measure θ1 (the angle formed by the interface of the optically anisotropic layer with the tilt angle) and the tilt angle θ2 of the other surface. Therefore, in this specification, θ1 and θ2 are calculated by the following method. Although this method does not accurately represent the actual orientation state, it is effective as a means of expressing the relative relationship between some optical properties of the optical film.
In this method, the following two points are assumed and the tilt angle at the two interfaces of the optically anisotropic layer is assumed for easy calculation.
1. The optically anisotropic layer is assumed to be a multilayer body composed of rod-shaped compounds or layers containing rod-shaped compounds. Further, it is assumed that the minimum unit layer (the tilt angle of the rod-like liquid crystal compound is uniform in the layer) constituting it is optically uniaxial.
2. It is assumed that the tilt angle of each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer.
The specific calculation method is as follows.
(1) In a plane in which the tilt angle of each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer, the incident angle of the measurement light to the optically anisotropic layer is changed, and three or more The retardation value is measured at the measurement angle. In order to simplify the measurement and calculation, it is preferable to measure the retardation value at three measurement angles of −40 °, 0 °, and + 40 °, with the normal direction to the optically anisotropic layer being 0 °. . Such measurement is performed by, for example, KOBRA-21ADH, KOBRA-WR (manufactured by Oji Scientific Instruments), transmission type ellipsometer AEP-100 (manufactured by Shimadzu Corporation), M150, M520 (JASCO Corporation) )), ABR10A (manufactured by UNIOPT Co., Ltd.) and the like.
(2) The refractive index of ordinary light in each layer is no, the refractive index of extraordinary light is ne (no and ne are the same values in all layers), and the thickness of the entire multilayer body is d. Furthermore, based on the assumption that the tilt direction in each layer and the optical axis direction of one axis of the layer coincide with each other, the calculation of the polar angle dependency of the retardation value of the optically anisotropic layer coincides with the measured value. Fitting is performed using the tilt angle θ1 on one surface of the optically anisotropic layer and the tilt angle θ2 and thickness d of the other surface as variables, and θ1, θ2, and d are calculated.
Here, known values such as literature values and catalog values can be used for no and ne. If the value is unknown, it can also be measured using an Abbe refractometer. The thickness of the optically anisotropic layer can also be measured by an optical interference film thickness meter, a cross-sectional photograph of a scanning electron microscope, or the like.
In general, the average tilt angle θ of the optically anisotropic layer can be obtained by a crystal rotation method.

  In the optically anisotropic layer A, the average inclination angle measured by the above method is preferably 10 to 85 ° as described above in the first embodiment, and more preferably 20 to 75 °. preferable. Moreover, in the said 2nd-4th embodiment, it is preferable that it is 5-60 degrees as above-mentioned, and it is more preferable that it is 5-40 degrees. The average tilt angle of the rod-like liquid crystal can be adjusted to the above-mentioned preferable range by selecting the production conditions such as the type of alignment film, the type or amount of additives used for production, or the alignment temperature or alignment time. . There may be a difference in tilt angle between the air interface and the alignment film interface.

Usable rod-like liquid crystalline compounds include, for example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, Examples include alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles. The rod-like liquid crystalline compound includes a metal complex. Moreover, the liquid crystal polymer which contains a rod-shaped liquid crystalline compound in a repeating unit can also be used as a rod-shaped liquid crystalline compound. In other words, the rod-like liquid crystalline compound may be bonded to a (liquid crystal) polymer. As for rod-like liquid crystalline compounds, for example, Quarterly Chemistry Review Volume 22 Liquid Crystal Chemistry (1994) Chapter 4, Chapter 7 and Chapter 11 of the Chemical Society of Japan, and Liquid Crystal Device Handbook, Japan Society for the Promotion of Science, 142nd member Those described in Chapter 3 of the meeting can be adopted.
There is no restriction | limiting in particular as a birefringence of a rod-shaped liquid crystalline compound, Although it can select suitably according to the objective, 0.001-0.7 are preferable.

  In order to fix the rod-like liquid crystalline compound in the aligned state, it is preferable to use a rod-like liquid crystalline compound having a polymerizable group. Examples thereof include liquid crystal compounds having a polymerizable group of [Chemical Formula 11] and [Chemical Formula 12] in paragraph numbers [0049] to [0050] of JP-A-2004-339193. Among these, liquid crystal compounds having an acrylate group and / or a methacrylate group are particularly preferable. Specific examples of the rod-like liquid crystal compound having one or two acrylate groups and / or methacrylate groups include paragraph numbers [0082] to [0105] of JP-A-8-3111 and paragraphs of JP-A-9-281331. Nos. [0022] to [0040], paragraph numbers [0115] to [0128] of JP-A No. 2000-281628, paragraph numbers [0250] to [0400] of JP-A No. 2002-220421, JP-A No. 2003-48903 And the compounds described in paragraph numbers [0056] to [0075] of the publication. Specific examples of the liquid crystal compound having two or more polymerizable acrylate groups and / or methacrylate groups include compounds described in JP-A-2002-30042.

  Two or more rod-like liquid crystal compounds may be used. Examples of preferred combinations include a combination of at least one rod-like liquid crystal represented by the following formula (I) and at least one rod-like liquid crystal represented by the following formula (II).

In the formula, A and B each represent an aromatic or aliphatic hydrocarbon ring or a heterocyclic group; R ^{1 to} R ⁴ are each substituted or unsubstituted C ^{1 to} 12 (preferably C 3 to 7). Or an alkoxy group, an acyloxy group, an alkoxycarbonyl group or an alkoxycarbonyloxy group containing a C1-12 (preferably C3-7) alkylene chain; R ^a , R ^b and R ^c each represent ^a substituent. X; y and z each represents an integer of 1 to 4;

In the above formula, the alkyl chain contained in R ^{1 to} R ⁴ may be either linear or branched. More preferably, it is linear. In order to cure the composition, R ^{1 to} R ⁴ preferably have a polymerizable group at the end, and examples of the polymerizable group include an acryloyl group, a methacryloyl group, and an epoxy group. included.

In the above formula (I), x and z are preferably 0 and y is preferably 1, and one R ^b is a substituent at the meta position or the ortho position with respect to the oxycarbonyl group or acyloxy group. Is preferred. R ^b is preferably a C1-12 alkyl group (for example, a methyl group), a halogen atom (for example, a fluorine atom), or the like.

  In the formula (II), each of A and B is preferably a phenylene group or a cyclohexylene group, and both A and B are phenylene groups, or one is a cyclohexylene group and the other is phenylene. A group is preferred.

  Specific examples of the compound represented by the general formula (I) and specific examples of the compound represented by the general formula (II) are shown below, but are not limited to the following specific examples.

  There is no restriction | limiting in particular about the ratio of the compound of the said general formula (I) and (II). In order to form an optically anisotropic layer satisfying the above characteristics, an equal amount may be used, or one of them may be used as a main component and the other as a subcomponent.

The liquid crystalline compound may be composed of two or more kinds of liquid crystalline compounds having different numbers of polymerizable groups contained in one molecule, and each liquid crystalline compound has one or more polymers in one molecule. It preferably has a functional group.
There is no restriction | limiting in particular as a kind of the said liquid crystalline compound which has a polymeric group, According to the objective, it can select suitably, The liquid crystalline compound which has 1-5 acrylate groups and / or methacrylate groups is preferable. 1 to 4 liquid crystal compounds are more preferable, and liquid crystal compounds having 1 to 2 acrylate groups and / or methacrylate groups are more preferable. Each of them is particularly preferably a rod-like liquid crystal compound having an acrylate group. By using one or more, the degree of orientational order is reduced, but the number of polymerizable groups increases, which is preferable because adhesion is improved. The number of 5 or less is preferable because the orientation degree tends to increase. The optically anisotropic layer preferably contains liquid crystal compounds having the same polymerizable group, and has two or more rod-like liquid crystal compounds having different acrylate groups and 1 to 4 polymerizable groups. It is preferable to have two or more rod-like liquid crystal compounds having different one or two polymerizable groups.

The liquid crystal compound preferably contains two types of liquid crystal compounds in which the number of polymerizable groups of the liquid crystal compound is m and n. Here, m and n are each a positive integer and m> n. The content of the compound having n polymerizable groups is preferably 50% by weight or less, more preferably 1.0 to 10% by weight based on the compound having m polymerizable groups. In particular, even if a liquid crystal compound having one acrylate group is added to a rod-like liquid crystal compound having two acrylate groups in an amount of more than 50% based on the total weight of the rod-like liquid crystal compound, the degree of alignment order is improved. As the content of the rod-like liquid crystal compound having an acrylate group is decreased, the degree of polymerization of the optically anisotropic layer is decreased, and the adhesion with the support tends to be deteriorated. Therefore, it is preferable to add 0.5 to 50% by weight of a rod-like liquid crystal compound having one acrylate group with respect to the total weight of the rod-like liquid crystal compound in order to maintain adhesion, and 0.5 to 20% by weight is preferable. More preferably, the degree of polymerization is preferably at least 85% or more, and more preferably 90% or more.
The liquid crystalline compound may be a high molecular liquid crystalline compound or a low molecular liquid crystalline compound. Furthermore, it is preferable that the alignment state is maintained and fixed. Examples of the liquid crystalline compound include those that are cross-linked when forming the optically anisotropic layer and then no longer show liquid crystal.

The optically anisotropic layer A may contain an additive together with the rod-like liquid crystalline compound. Examples of the additive include a plasticizer, a surfactant, a polymerization initiator, a polymerizable monomer, and a polymer. These additives are preferably compatible with essential components such as a liquid crystal compound and contribute to control of the tilt angle of the liquid crystal compound or do not inhibit alignment.
As the polymerizable monomer, for example, a compound having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group is preferable. Other examples include radical polymerizable or cationic polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. As addition amount of the said compound, 1-50 mass% is preferable with respect to a liquid crystalline compound, and it is more preferable that it is 3-30 mass%. In addition, it is more preferable to use a monomer having a polymerizable reactive functional group number of 3 or more in admixture because the adhesion between the alignment film and the optically anisotropic layer can be improved.

  The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably 0.1 to 10% by mass, more preferably 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. . The degree of butyrylation of cellulose acetate butyrate (cellulose acetate butyrate) is preferably 30% or more, particularly preferably in the range of 30 to 80%. The degree of acetylation is preferably 30% or more, particularly preferably in the range of 30 to 80%. The viscosity of cellulose acetate butyrate (value obtained by measurement according to ASTM D-817-72) is preferably in the range of 0.01 to 20 seconds.

  Examples of the surfactant include conventionally known compounds, but fluorine compounds are preferable. Specifically, for example, compounds described in paragraphs [0028] to [0056] in JP-A-2001-330725, paragraphs [0069] to [0126] in JP-A-2005-062673. ] The compound of description is mentioned. Particularly preferred examples include the fluoroaliphatic group-containing polymers described in paragraph numbers [0054] to [0109] in JP-A-2005-292351.

The composition may contain one or more additives in order to bring the molecules of the liquid crystal compound into a desired alignment state and to improve the applicability or curability of the composition.
In order to hybrid-align the molecules of the rod-like liquid crystal compound, an additive capable of controlling the orientation on the air interface side of the layer (hereinafter referred to as “air interface orientation control agent”) may be added. Examples of the additive include low molecular weight or high molecular weight compounds having a hydrophilic group such as a fluorinated alkyl group and a sulfonyl group. Specific examples of usable air interface orientation control agents include compounds described in JP-A 2006-267171.

  Moreover, when the said composition is prepared as a coating liquid and the said 1st optically anisotropic layer is formed by application | coating, you may add surfactant for the improvement of applicability | paintability. As the surfactant, a fluorine-based compound is preferable, and specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725. Commercially available “Megafac F780” (manufactured by Dainippon Ink) may also be used.

  Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970). The addition amount of the photopolymerization initiator is preferably 0.01 to 20% by mass and more preferably 0.5 to 5% by mass with respect to the solid content of the coating solution.

Moreover, it is preferable that the said composition contains the polymerization initiator. The polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator, but a photopolymerization initiator is preferable from the viewpoint of easy control. Examples of photopolymerization initiators that generate radicals by the action of light include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670) and acyloin ethers (described in US Pat. No. 2,448,828). ), Α-hydrocarbon substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), triarylimidazole dimers and p-amino Combination with phenyl ketone (described in US Pat. No. 3,549,367), acridine and phenazine compounds (described in JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970) Description), acetophenone series Compounds, benzoin ether compounds, benzyl compounds, benzophenone compounds, thioxanthone compounds and the like are preferable. Examples of the acetophenone compound include 2,2-diethoxyacetophenone, 2-hydroxymethyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy -2-methyl-propiophenone, p-dimethylaminoacetone, p-tert-butyldichloroacetophenone, p-tert-butyltrichloroacetophenone, p-azidobenzalacetophenone and the like. Examples of the benzyl compound include benzyl, benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal, 1-hydroxycyclohexyl phenyl ketone and the like. Examples of the benzoin ether compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, and benzoin isobutyl ether. Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, Michler's ketone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, and the like. Examples of the thioxanthone compound include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and the like. Among such photosensitive radical polymerization initiators composed of aromatic ketones, acetophenone compounds and benzyl compounds are particularly preferable in terms of curing characteristics, storage stability, odor, and the like. The photosensitive radical polymerization initiators composed of these aromatic ketones can be used alone or in combination of two or more according to the desired performance.
In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, thioxanthone and the like.

  Multiple photopolymerization initiators may be combined, and the amount used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. The light irradiation for the polymerization of the liquid crystal compound preferably uses ultraviolet rays.

Apart from the polymerizable liquid crystal compound, the composition may contain a non-liquid crystalline polymerizable monomer. As the polymerizable monomer, a compound having a vinyl group, a vinyloxy group, an acryloyl group or a methacryloyl group is preferable. Note that it is preferable to use a polyfunctional monomer having two or more polymerizable reactive functional groups, for example, ethylene oxide-modified trimethylolpropane acrylate because durability is improved.
Since the non-liquid crystalline polymerizable monomer is a non-liquid crystalline component, the addition amount thereof does not exceed 15% by mass with respect to the liquid crystal compound, and is preferably about 0 to 10% by mass.

  The optically anisotropic layer A can be formed by setting a curable composition containing one or more rod-shaped liquid crystal compounds to a desired alignment state, and then curing the composition by advancing the reaction. The curable composition is usually prepared as a coating solution dissolved in a solvent. In general, the coating solution is applied to the rubbing surface of the alignment film, dried and the solvent is removed to bring the rod-like liquid crystal into a desired alignment state, and then the polymerization reaction is advanced by UV irradiation to cure. It is. From the viewpoint of production suitability, it is preferable to use a rod-like liquid crystalline compound exhibiting a nematic liquid crystal phase in a temperature range of 50 to 150 ° C.

  As a solvent used for preparation of a coating liquid, an organic solvent is preferable. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethyl sulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides (eg , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane), alkyl halides and ketones Is preferred. The said organic solvent may be used individually by 1 type, and may use 2 types together. When the surface tension of the coating solution is 25 mN / m or less (more preferably 22 mN / m or less), an optically anisotropic layer with high uniformity can be formed.

  Application of the coating liquid is a known method (for example, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, curtain coating method, spin coating dip coating method, wing method, printing coating). , Spray coating method, slot coating method, roll coating method, slide coating method, blade coating method, gravure coating method). Among these, application by a wire bar coating method or a die coating method is preferable.

  The immobilization is preferably performed by a polymerization reaction. Examples of the polymerization reaction include a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and among these, a photopolymerization reaction is preferable. As described above, the coating liquid preferably contains a polymerizable monomer or a polymerization initiator that contributes to the fixation of the liquid crystalline compound.

Ultraviolet light is preferably used for light irradiation for fixing the alignment of the liquid crystal compound (liquid crystal molecule). The irradiation energy is not particularly limited but is preferably ^{20mJ / cm 2 ~50J / cm 2} , more preferably ^{20mJ / cm 2 ~5000mJ / cm 2} , 100mJ / cm 2 ~800mJ / cm 2 is more preferable. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. Although there is no restriction | limiting in particular as temperature for fixing orientation, Generally 100 degreeC or less is preferable and 80 degreeC or less is more preferable. Moreover, in order to maintain the adhesiveness of an optically anisotropic layer and a support body, it is preferable to harden | cure at 40 degreeC or more.

  The thickness of the optically anisotropic layer is preferably from 0.1 to 20 μm, more preferably from 0.5 to 15 μm, still more preferably from 1 to 10 μm. A protective layer may be provided on the optically anisotropic layer.

For the formation of the optically anisotropic layer A, it is preferable to use an alignment film. There is no restriction | limiting in particular as an alignment film used, Although it can select suitably according to the objective, Usually, a polymer is utilized. As the polymer, any of a polymer that can be crosslinked by itself, a polymer that is crosslinked by a crosslinking agent, and a combination thereof can be used.
Examples of the polymer used for the alignment film include compounds described in paragraph [0022] of JP-A-8-338913. Among these, water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are preferable. Further preferred.

There is no restriction | limiting in particular as a saponification degree of polyvinyl alcohol, Although it can select suitably according to the objective, 70-100% is preferable, 80-100% is more preferable, 85-95% is still more preferable.
There is no restriction | limiting in particular as a polymerization degree of polyvinyl alcohol, Although it can select suitably according to the objective, It is preferable that it is 100-3000.

  The modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of the modifying group include a hydrophilic group (carboxylic acid group, sulfonic acid group, phosphonic acid group, amino group, ammonium group, amide group, thiol group, etc.), a hydrocarbon group having 10 to 100 carbon atoms, and a fluorine atom. Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. Specific examples of the modified polyvinyl alcohol compound include, for example, paragraph No. [0074] of JP-A No. 2000-56310, paragraph Nos. [0022] to [0145] of JP-A No. 2000-155216, and No. 2002-62426. In paragraph Nos. [0018] to [0022]. As an example in which orientation is imparted to the support itself, there is a technique described in JP-A-9-281331.

  Also, a polyimide film (preferably a fluorine atom-containing polyimide) widely used as an alignment layer for LCD is also preferable as the organic alignment layer. For this, polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd., SE series manufactured by Nissan Chemical Co., Ltd., etc.) was applied to the support surface and baked at 100 to 300 ° C. for 0.5 to 1 hour. Thereafter, it is obtained by rubbing. Further, the orientation layer according to the present invention can be obtained by introducing a reactive group into the polymer, or by using the polymer together with a crosslinking agent such as an isocyanate compound and an epoxy compound and curing these polymers. It is preferable that it is a cured film.

  The alignment state of the liquid crystal in the optically anisotropic layer A depends on the surface energy of the contact surfaces (for example, the support or the air surface) of various liquid crystal layers and the combination of the kinds of liquid crystal compounds to be mixed. Since it has a so-called hybrid orientation and its inclination changes, it can be controlled by these factors. For example, as described above, the inclination angle of the rod-like structural unit on the support side is generally adjusted by selecting a liquid crystal compound or an alignment film material used in the present invention, or by selecting a rubbing treatment method. be able to. In addition, the inclination angle of the liquid crystal structural unit on the surface side (air side) is generally determined by the liquid crystal compound used in the present invention or other compounds (eg, plasticizers, surfactants, polymerizable monomers and polymers) used together with these. It can be prepared by selecting. Furthermore, the degree of change in the tilt angle can be adjusted by the above selection.

  Among the orientation layers described above, suitable orientation layers for forming a liquid crystalline compound in a nematic hybrid orientation include rubbing polyimide-containing orientation layers, rubbing polyethersulfone-containing orientation layers, and rubbing polyphenylene sulfide-containing orientation layers. And a rubbing polyethylene terephthalate-containing orientation layer, a rubbing polyethylene phthalate-containing orientation layer, a rubbing polyarylate-containing orientation layer, and a cellulose-based plastic-containing orientation layer.

As a liquid crystal alignment control method other than the rubbing method, there is an oblique vapor deposition method using an oblique vapor deposition film such as SiO (Japanese Patent Laid-Open No. 56-66826). Examples of the vapor deposition material for the inorganic oblique vapor deposition film include SiO ₂ , metal oxides such as TiO ₂ and ZnO ₂ , fluorides such as MgF ₂ , and metals such as Au and Al. The metal oxide can be used as an oblique deposition material as long as it has a high dielectric constant, and is not limited to the above. The inorganic oblique deposition film can be formed using a deposition apparatus. An inorganic oblique vapor deposition film can be formed by fixing the film (support) and performing vapor deposition, or moving the long film and performing continuous vapor deposition. As another method, a photolithographic method (Japanese Patent Laid-Open No. 60-60624, etc.) for forming grating-like irregularities on the surface of the alignment film by a method such as photolithography, a polymer chain in the pulling direction during accumulation on the substrate. LB film method (Japanese Patent Laid-Open No. 62-195622, etc.) for aligning ions, ion irradiation method for obliquely irradiating ions, etc. (Japanese Patent Laid-Open No. 3-83017, etc.), and high-speed liquid jet method (in Japanese) No. 63-96631), ice blasting method in which ice pieces are ejected obliquely (Japanese Patent Laid-Open No. 63-96630), and excimer laser method in which excimer laser is irradiated on the polymer surface to form periodic stripe patterns. (JP-A-2-196219, etc.), an electron beam scanning method (JP-A-4-97130, etc.) in which a thermoplastic material is scanned with an electron beam to form fine irregularities. Centrifugal method in which a polymer chain is oriented by applying a heart force (Japanese Patent Laid-Open No. 63-213819), and a stamping method in which the orientation ability is transferred by press-bonding an already-oriented substrate (Japanese Patent Laid-Open No. 6-43457, etc.) Y. Random orientation method (J. Appl. Phys. A74 (3), p2071 (1993)) twisted by adding a chiral agent by Toko et al., Photodecomposition method of photodegrading a polyimide film by polarized ultraviolet light by Hasegawa et al. Liquid crystal debate proceedings, p232 (article number 2G604) (1994)) and the like have been proposed.

  In addition, a magnetic field or an electric field is used as a means for aligning the liquid crystalline compound, and a magnetic field is particularly preferable as a means for aligning liquid crystal molecules obliquely as in the present invention. Therefore, a liquid crystal compound is mixed in the polymer matrix to disperse the liquid crystal molecules in the polymer matrix, and this is applied onto the support sheet, and an external magnetic field is applied at an angle with respect to the normal direction of the support sheet surface. By adding, liquid crystal molecules can be aligned in that direction. In this case, the magnetic field strength is preferably 500 G or more, but the liquid crystal having a low intrinsic viscosity can be aligned even with a magnetic field of 500 G or less.

(Optically anisotropic layers B and C)
In the present invention, optically anisotropic layers B and C having a total in-plane retardation of 0 to 300 nm are used. The optically anisotropic layers B and C do not need to be adjacent to each other. In the LCD 4 of the embodiment shown in FIG. 8, the optically anisotropic layer A is disposed between the optically anisotropic layers B and C. May be.
In the first and fourth embodiments, a preferable combination example of the optically anisotropic layers B and C from the viewpoint of optical characteristics is such that the in-plane retardation of the optically anisotropic layer C is 0 to 0 as described above. 300 nm, the retardation in the thickness direction is −200 to 300 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 300 nm. A more preferable combination example is that the in-plane retardation of the optically anisotropic layer C is 0 to 200 nm, the retardation in the thickness direction is 0 to 250 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 0 nm. 200 nm.
In addition, in a preferred combination example of the optically anisotropic layers B and C, in the second and third embodiments, the in-plane retardation of the optically anisotropic layer C is 0 to 300 nm, and the retardation in the thickness direction is The in-plane retardation of the optically anisotropic layer B is 0 to 300 nm. A more preferable combination example is that the in-plane retardation of the optically anisotropic layer C is 0 to 200 nm, the retardation in the thickness direction is 0 to 200 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 200 nm. 150 nm.

From the viewpoint of materials, the optically anisotropic layers B and C are not particularly limited. Similarly to the optically anisotropic layer A, it may be a layer formed by curing a liquid crystal composition or a layer made of a birefringent polymer film. In the first to fourth embodiments, since the optically anisotropic layer C is adjacent to the first and second polarizers, in these embodiments, the optically anisotropic layer C is a birefringent polymer film. Since it can utilize also as a protective film of a polarizer, it is preferable. Examples of the birefringent polymer film that can be used as the optically anisotropic layers B and C include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene polymer, polycarbonate polymer, and cycloolefin polymer. Examples thereof include a film containing a polymer or the like as a main raw material. Especially, the film which uses cellulose ester as a main raw material especially in the point which can reduce manufacturing cost is preferable. In addition, a film using a cycloolefin-based polymer as a main raw material is also preferable from the viewpoint that a change in retardation humidity is small. Further, an additive capable of expressing in-plane retardation Re and / or retardation Rth in the thickness direction may be added to the polymer film to produce a polymer film satisfying the above optical characteristics.
As cellulose acylates, cellulose acetate having an acetyl group can be mentioned as a typical example. In addition, so-called CAP and CAB having a propionyl group or a butyryl group together with an acetyl group can also be used ( This will be described later).
From the viewpoint of improving the frame unevenness, the polymer film used as the optically anisotropic layer B or C is preferably a thin film (for example, about 40 μm). Depending on the application, it is also preferable that the wavelength dispersion of Re and Rth is reverse dispersion.

  The polymer film used as the optically anisotropic layer B or C may be a film produced by either a melt film forming method or a solution film forming method. The cellulose ester film is preferably formed by a solution casting (solvent cast) method. The thickness of the film is preferably about 20 to 500 μm, and more preferably about 40 to 200 μm. In order to improve the adhesion between the film and the layer provided thereon (adhesive layer or optically anisotropic layer), the film is subjected to a surface treatment (for example, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment, Acid treatment or alkali treatment) may be performed. An adhesive layer (undercoat layer) may be provided on the film. Moreover, it is preferable that the film contains a polymer having a polymerizable group, etc., because the adhesion to the optically anisotropic layer formed by curing by a polymerization reaction is improved. Moreover, in order to give the film the slipperiness in a conveyance process, or to prevent sticking of the back surface and the surface after winding up, the inorganic particle whose average particle size is 10-100 nm is solid content weight. A polymer layer mixed at a ratio of 5% to 40% may be formed on one side of the film by coating or co-casting.

Even if the acyl substituent of the cellulose acylate used as the material of the cellulose acylate film for the optically anisotropic layers B and C is, for example, a cellulose acylate composed of an acetyl group alone, a cellulose having a plurality of acyl substituents A composition containing acylate may be used. Preferable examples of cellulose acylate have a total acylation degree of 2.3 to 3.0, and more preferably 2.4 to 2.95.
Moreover, the mixed fatty acid ester which has another fatty acid ester residue with an acetyl group is also preferable. The number of carbon atoms in the aliphatic acyl group of the fatty acid ester residue is preferably 2 to 20, and specific examples include acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl, hexanoyl, octanoyl, lauroyl, stearoyl and the like. . Among them, it is preferable to use cellulose acylate having an acyl group selected from propionyl group, butyryl group, pentanoyl group and hexanoyl group together with acetyl group, and the degree of substitution satisfies the following formulas (1) to (3). More preferably, cellulose acylate is used.
(1) 2.0 ≦ X + Y ≦ 3.5
(2) 0 ≦ X ≦ 2.5
(3) 0.4 ≦ Y ≦ 2.9
In the formulas (1) to (3), X represents the substitution degree of the acetyl group in cellulose acylate, and Y is an acyl group selected from propionyl group, butyryl group, pentanoyl group, and hexanoyl group in cellulose acylate. Indicates the sum of the degree of substitution.

  The cellulose acylate preferably has a mass average degree of polymerization of 350 to 800, and more preferably has a mass average degree of polymerization of 370 to 600. The cellulose acylate used in the present invention preferably has a number average molecular weight of 70000 to 230,000, more preferably 75000 to 230,000, and more preferably 78000 to 120,000. Further preferred.

  The cellulose acylate film is preferably produced by a solution casting method or a melt casting method. Examples of producing a cellulose acylate film using a solution casting method are described in US Pat. Nos. 2,336,310, 2,367,603, 2,492,078, and 2,492,977. 2,492,978, 2,607,704, 2,739,069 and 2,739,070, British Patent Nos. 640731 and 736892 And JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, JP-A-62-115035, and the like. The cellulose acylate film exhibits in-plane retardation Re reverse wavelength dispersibility by being subjected to a stretching treatment. Regarding the stretching method and conditions, for example, refer to the examples described in JP-A-62-115035, JP-A-4-152125, JP-A-4284221, JP-A-4298310, JP-A-11-48271, etc. Can be.

An example of a polymer film that can be used as the optically anisotropic layers B and C (preferably the optically anisotropic layer C) is a low-substitution layer containing, as a main component, cellulose acylate that satisfies the following formula (I). It is a low-substituted cellulose acylate film.
(1) 2.0 <Z1 <2.7
(In formula (1), Z1 represents the total acyl substitution degree of the cellulose acylate of the low substitution degree layer.)
The distance between the liquid crystal panel unit and the backlight unit becomes closer, the optical film etc. is distorted by the heat from the backlight, a phase difference occurs at the edge of the liquid crystal display device, and frame-like light leakage occurs during black display. There is a problem that occurs. When the low-substituted cellulose acylate film is used, desired optical characteristics can be achieved with a thinner thickness compared to the case of using the high-substituted cellulose acylate. As a result, the distance between the liquid crystal panel unit and the backlight unit can be increased without increasing the overall thickness, and frame-like light leakage can be reduced.
In the present specification, “contains as a main component” means an ingredient having the highest mass fraction in an embodiment in which the component as a raw material is one kind, and an ingredient having two or more ingredients. To do.

The low substitution layer may have a high substitution layer containing, as a main component, cellulose acylate satisfying the following formula (2) on at least one surface thereof.
(2) 2.7 <Z2
(In formula (2), Z2 represents the total acyl substitution degree of the cellulose acylate of the high substitution degree layer.)

  Examples of the cellulose acylate used for the production of the low-substituted cellulose acylate film include cotton linter and wood pulp (hardwood pulp, conifer pulp), and cellulose acylate obtained from any raw material cellulose can also be used. You may mix and use depending on the case. Detailed descriptions of these raw material celluloses can be found, for example, by Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Institute of Invention and Technology Publication No. 2001 The cellulose described in No.-1745 (pages 7 to 8) can be used.

  The raw material cellulose acylate used for the production of the low-substituted cellulose acylate film is acylated with two or more types of acyl groups, even if it is acylated with one type of acyl group. May be. It is preferable to have an acyl group having 2 to 4 carbon atoms as a substituent. When two or more types of acyl groups are used, one of them is preferably an acetyl group, and the acyl group having 2 to 4 carbon atoms is preferably a propionyl group or a butyryl group. With these films, a solution having a preferable solubility can be prepared, and in particular, in a non-chlorine organic solvent, a good solution can be prepared. Furthermore, a solution having a low viscosity and good filterability can be prepared.

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by acylating part or all of these hydroxyl groups with an acyl group. The degree of acyl substitution means the sum of the ratios of acylation of the hydroxyl groups of cellulose located at the 2-position, 3-position and 6-position (100% acylation at each position is substitution degree 1).

  The acyl group having 2 or more carbon atoms may be an aliphatic group or an allyl group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include acetyl group, propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, isobutanoyl group Group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like. Among these, an acetyl group, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a tert-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and an acetyl group is particularly preferable. A propionyl group and a butanoyl group (when the acyl group has 2 to 4 carbon atoms), more preferably an acetyl group (when the cellulose acylate is cellulose acetate).

  In the acylation of cellulose, when an acid anhydride or acid chloride is used as an acylating agent, an organic acid such as acetic acid or methylene chloride is used as an organic solvent as a reaction solvent.

  As the catalyst, when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used. When the acylating agent is an acid chloride (for example, CH3CH2COCl), a basic compound is used. Used.

  The most common industrial synthesis method of cellulose mixed fatty acid ester is to use cellulose corresponding to fatty acid corresponding to acetyl group and other acyl groups (acetic acid, propionic acid, valeric acid, etc.) or their anhydrides. This is a method of acylating with a mixed organic acid component.

In the present invention, it is from the viewpoint of retardation wavelength dispersion that the cellulose acylate film of the low-substituted cellulose acylate film satisfies the following formulas (3) and (4). preferable.
Formula (3) 1.0 <X1 <2.7
(In Formula (3), X1 represents the substitution degree of the acetyl group of the cellulose acylate in the low substitution degree layer.)
Formula (4) 0 <= Y1 <1.5
(In Formula (4), Y1 represents the total substitution degree of acyl groups having 3 or more carbon atoms in the cellulose acylate of the low substitution degree layer.)
Note that the relationship X1 + Y1 = Z1 holds between X1 and Y1 and Z1 in the formula (1).

The cellulose acylate used in the high substitution layer of the low substitution cellulose acylate film preferably satisfies the following formulas (5) and (6) from the viewpoint of retardation wavelength dispersion.
Formula (5) 1.2 <X2 <3.0
(In Formula (5), X2 represents the substitution degree of the acetyl group of the cellulose acylate in the high substitution degree layer.)
Formula (6) 0 <= Y2 <1.5
(In Formula (6), Y2 represents the total substitution degree of acyl groups having 3 or more carbon atoms in the cellulose acylate of the high substitution degree layer.)
Note that the relationship of X2 + Y2 = Z2 holds between X2 and Y2 and Z2 in the formula (2).

  The cellulose acylate used in the present invention can be synthesized, for example, by the method described in JP-A-10-45804.

If necessary, a non-phosphate ester compound, a plasticizer, a retardation developer, a deterioration inhibitor, an ultraviolet absorber, a release accelerator, a matting agent, and the like may be added.
The low-substituted cellulose acylate film is preferably produced by a solution casting method as in the case of the cellulose acylate film, and is subjected to stretching treatment after the solution casting to bring the optical properties within a desired range. preferable.

The cycloolefin polymer used as the material for the cycloolefin polymer film such as the optically anisotropic layers B and C may be a homopolymer or a copolymer.
Examples of cycloolefin homopolymers and copolymers include, for example, ring-opening polymers of polycyclic monomers. Specific examples of the polycyclic monomer include the following compounds, but are not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [2.2.1] hept-2-ene,
5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-cyanobicyclo [2.2.1] hept-2-ene,
8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-fluorobicyclo [2.2.1] hept-2-ene,
5-fluoromethylbicyclo [2.2.1] hept-2-ene,
5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,
5,5-difluorobicyclo [2.2.1] hept-2-ene,
5,6-difluorobicyclo [2.2.1] hept-2-ene,
5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,
8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene.
These can be used alone or in combination of two or more.
Although there is no restriction | limiting in particular about these molecular weights, Generally, it is preferable that it is 5000-500000, and it is more preferable that it is 10,000-100000. Also, commercially available cycloolefin polymers include the ARTON series (manufactured by JSR Corporation), the ZEONOR series (manufactured by ZEON Corporation), the ZEONEX series (manufactured by ZEON Corporation), and ESCINA (Sekisui Chemical Co., Ltd.). Can be used. In the case of using a commercially available polymer film, the optical properties may be adjusted so as to satisfy the above formula by performing a stretching treatment. For example, when a ZEONOR series polymer film is used, it is required for the second optically anisotropic layer by performing longitudinal stretching (stretching in the film longitudinal direction) and / or lateral stretching (stretching in the film width direction). It can be set as the polymer film which satisfies an optical characteristic. The longitudinal draw ratio is preferably 1 to 150%, and the transverse draw ratio is preferably 2 to 200%.

  In order to achieve the optical properties satisfying the properties required for the optically anisotropic layers B and C, after forming a film by the solution casting method, in the longitudinal direction and the width direction of the cycloolefin-based polymer film It is preferable to perform a stretching treatment. The stretching ratio is preferably 1 to 200%. The stretching process in the longitudinal direction can be performed by the difference in the number of rotations of the roll holding the film, and the stretching process in the width direction can be performed using a tenter.

  An example of a method for producing a cellulose acylate film for the optically anisotropic layer C includes a casting step of casting a polymer solution to form a web, and a residual solvent amount of the web formed in the casting step. Between 100 and 300% by mass, including a stretching step of stretching 5 to 100% in the transport direction and a drying step of drying the web at a film surface temperature of 50 to 150 ° C. This is a production method having a volatile content of 10 to 150% by mass and a final residual volatile content of 10 to 50% by mass. According to this method, a cellulose acylate film suitable as the optically anisotropic layer C can be stably produced.

  As the norbornene-based polymer used as the material of the norbornene-based polymer film for the optically anisotropic layers B and C, commercially available products such as Arton (manufactured by JSR) and Zeonex (manufactured by Nippon Zeon) are trade names. A commercially available product may be used. However, when the characteristics required for the second optically anisotropic layer are not satisfied, it is preferable to use a film subjected to a treatment such as stretching.

  Examples of the polycarbonate polymer used as the material of the polycarbonate polymer film for the optically anisotropic layers B and C include, for example, Pure Ace (manufactured by Teijin Chemicals Ltd.), Elmec (manufactured by Kaneka), and Illuminex (Japan GE Plastics). You may use what is marketed by the brand name of the product made from Su.

In order to satisfy the optical properties required for the optically anisotropic layers B and C, in the polymer film, a retardation Rth enhancer and reducer in the thickness direction, and an in-plane retardation Re enhancer and reducer Any one of these may be added. Here, the “Rth enhancer” is a compound having the property of developing birefringence in the thickness direction of the film. As the Rth enhancer, a compound having a large polarizability anisotropy having an absorption maximum in a wavelength range of 250 nm to 380 nm is preferable. The content of retardation Rth developing agent in the thickness direction with respect to 100 parts by mass of cellulose acylate is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, and still more preferably 3 to 15% by mass.
As the usable retardation Rth enhancer in the thickness direction, it is preferable not to affect the in-plane retardation Re developed by stretching, and it is preferable to use a discotic compound.
Examples of the in-plane retardation Re developing agent that can be used include the rod-shaped aromatic compounds described in JP-A-2004-50516, pages 11-14.
Examples of usable retardation Rth reducing agents in the thickness direction include compounds described in JP-A No. 2005-301227.
The amount of these additives used is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the polymer component.

The polymer film used for the optically anisotropic layers B and C may contain fine particles as a matting agent. Fine particles that can be used as a matting agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and Mention may be made of calcium phosphate. As the fine particles, those containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. As the fine particles of silicon dioxide, for example, commercially available products such as “Aerosil” R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 {above, manufactured by Nippon Aerosil Co., Ltd.} can be used. . Zirconium oxide fine particles are commercially available, for example, under the trade names of “Aerosil” R976 and R811 {manufactured by Nippon Aerosil Co., Ltd.}, and any of them can be used as a matting agent.
The amount of the matting agent used is preferably 0.01 to 0.3 parts by mass with respect to 100 parts by mass of the polymer component.

  As described above, the optically anisotropic layer B or C may be a layer formed from a liquid crystal composition. Further, like the optically anisotropic layer A, the optically anisotropic layer B or C is a layer containing a rod-like liquid crystal fixed in an alignment state. There may be. Examples of rod-shaped liquid crystals, examples of additives, and examples of formation methods are the same as those for the optically anisotropic layer A. For example, in an embodiment in which the optically anisotropic layer C is a polymer film, the optically anisotropic layer B made of a liquid crystal composition may be formed thereon using the polymer film that is the optically anisotropic layer as a support. it can.

The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. Example 3 is a reference example.

1. Example 1
(Preparation of optically anisotropic layer C (cellulose acylate film))
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.
(Cellulose acetate solution composition)
――――――――――――――――――――――――――――――
Cellulose acetate having an acetylation degree of 60.9% 100 parts by mass Triphenyl phosphate (plasticizer) 7.8 parts by mass Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass Methylene chloride (first solvent) 300 parts by mass Methanol (No. 2 solvents) 45 parts by mass dye (360FP, manufactured by Sumika Finechem Co., Ltd.) 0.0009 parts by mass ――――――――――――――――――――――――――― -

In another mixing tank, 16 parts by mass of the following retardation increasing agent, 80 parts by mass of methylene chloride and 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution.
A dope was prepared by mixing 464 parts by mass of the cellulose acetate solution having the above composition with 36 parts by mass of the retardation increasing agent solution and 1.1 parts by mass of silica fine particles (manufactured by Irosil, R972) and stirring sufficiently. The addition amount of the retardation increasing agent was 5.0 parts by mass with respect to 100 parts by mass of cellulose acetate. Moreover, the addition amount of silica fine particles was 0.15 mass part with respect to 100 mass parts of cellulose acetate.

The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., it was dried for 1 minute, peeled off, and then stretched 33% in the width direction using a tenter with a drying air of 140 ° C. Then, it dried for 20 minutes with 135 degreeC drying air, and manufactured the support body whose residual solvent amount is 0.3 mass%.
The thickness of the obtained support was 82 μm. It was 42 nm when the retardation value (Re) in wavelength 550nm was measured using the ellipsometer (M-150, JASCO Corporation make). Moreover, it was 145 nm when the retardation value (Rth) in wavelength 550nm was measured. This film was used as the optically anisotropic layer C.

(Formation of alignment film)
An alignment film coating solution having the following composition was continuously applied to the surface of the cellulose acetate film prepared above with a # 14 wire bar. 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. The formed film was continuously rubbed.
Composition of alignment film coating solution ――――――――――――――――――――――――――
The following modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight ――――――――――――――――――――――――――――

(Preparation of optically anisotropic layer B (rod-like liquid crystal composition layer))
A coating solution containing a rod-like liquid crystal compound having the following composition was continuously applied onto the alignment film with a # 4.0 wire bar. In order to dry the solvent of the coating solution and to mature the alignment of the rod-like liquid crystal compound, the coating liquid was heated for 60 seconds with hot air at 90 ° C. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form an optically anisotropic layer. This was used as the optically anisotropic layer B.
Composition of coating solution for optically anisotropic layer B ――――――――――――――――――――――――――――――――――
The following rod-like liquid crystalline compound 100 parts by mass photopolymerization initiator 3 parts by mass (Exemplary Compound 1 described in JP-A-2006-285187)
Sensitizer (Kaya Cure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following fluoropolymer (D) 0.4 part by mass The following horizontal alignment agent 0.2 part by mass Methyl ethyl ketone 342 parts by mass ――――――――――――――――――――――――――――

(Measurement of optical properties)
An optically anisotropic layer B formed on the glass substrate by the same method was subjected to in-plane retardation Re (550 nm) at a wavelength of 550 nm using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). ) Was measured, and the in-plane retardation Re (550) was 63 nm. Further, in the optically anisotropic layer B, the average tilt angle of the long axis of the rod-like liquid crystal with respect to the film surface is 0 °, and the fact that the rod-like liquid crystal is oriented horizontally with respect to the film surface is relative to the film normal direction. From the normal direction to 50 degrees on one side in 10 degree steps, light with a wavelength of 550 nm is incident from each inclined direction, and a total of 6 points are measured. The measured retardation value and assumed value of average refractive index and input Based on the measured film thickness value, it was confirmed from KOBRA 21ADH.

(Formation of alignment film)
An alignment film was formed in the same manner as the alignment film used when forming the optically anisotropic layer B.
At this time, rubbing treatment was performed in a direction orthogonal to the slow axis of the optically anisotropic layer B.

(Preparation of optically anisotropic layer A (rod-like liquid crystal composition layer))
A coating liquid containing a rod-like liquid crystal compound having the following composition was continuously applied onto the alignment film with a # 2.0 wire bar. In order to dry the solvent of the coating solution and to mature the alignment of the rod-like liquid crystal compound, the coating liquid was heated for 60 seconds with hot air at 90 ° C. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form an optically anisotropic layer. This was used as the optically anisotropic layer A. In this way, an optical compensation film was produced.
Composition of optically anisotropic layer A ────────────────────────────────
Composition of coating solution for optically anisotropic layer A────────────────────────────────
14.5% by mass of the above rod-like liquid crystalline compound
0.03 mass% of the following fluorosurfactant
The following sensitizer 0.15% by mass
The following photoinitiator 0.29 mass%
Methyl ethyl ketone 233.6% by mass
0.03 mass% of the following fluorine-containing compounds
────────────────────────────────

(Measurement of optical properties)
In-plane retardation Re (550) with a wavelength of 550 nm using an optically anisotropic layer A automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments) formed on a glass substrate by the same method. Was measured, and the in-plane retardation Re (550) was 31 nm. Further, in the optically anisotropic layer B, the rod-like compound molecules are fixed in a hybrid alignment state, there is no direction in which the retardation at a wavelength of 550 nm is 0 nm, and the absolute value of the retardation at a wavelength of 550 nm is Light with a wavelength of 550 nm from the inclined direction in 10 degree steps from the normal direction to 50 degrees on one side with respect to the film normal direction, indicating that the minimum direction is neither in the normal direction nor in the plane of the layer. 6 were measured in total, and it was confirmed from KOBRA 21ADH based on the measured retardation value, the assumed average refractive index, and the input film thickness value. The calculated average tilt angle of the rod-like liquid crystal compound was 60 °.

(Preparation of polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. The surface of the optical compensation film of the example on the support side and one surface of the polarizing film were attached using a polyvinyl alcohol-based adhesive. A commercially available cellulose acetate film (trade name “Fujitac”, manufactured by Fuji Film Co., Ltd.) was saponified and then attached to the other surface of the polarizing film using a polyvinyl alcohol-based adhesive to obtain an elliptically polarizing plate. .

(Production of TN mode liquid crystal display device)
A TN mode liquid crystal display device having the same configuration as that of FIG. 1 was produced. Specifically, a pair of polarizing plates provided in a liquid crystal display device (AL2216W, manufactured by Nippon Acer Co., Ltd.) using a TN mode liquid crystal cell is peeled off, and the polarizing plate 1 produced above is replaced with an optical compensation film. Are attached to the viewer side and the backlight side one by one through an adhesive so that the liquid crystal cell side becomes the liquid crystal cell side. At this time, the transmission axis of the polarizing plate 1 on the observer side and the transmission axis of the polarizing plate 1 on the backlight side were arranged so as to be orthogonal to each other. In this manner, a TN mode liquid crystal display device was produced.
The characteristics and arrangement of the prepared film are shown in the table below.

2. Example 2
(Preparation of optically anisotropic layer C (cellulose acylate film))
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.
(Cellulose acetate solution composition)
―――――――――――――――――――――――――――――――――――――
Cellulose acetate having an acetylation degree of 60.7 to 61.1% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 336 parts by weight Methanol (second solvent) 29 parts by mass 1-butanol (third solvent) 11 parts by mass ――――――――――――――――――――――――――――― ――――――――

  In another mixing tank, 16 parts by mass of the retardation increasing agent used in the production of the cellulose acylate film for the optically anisotropic layer C of Example 1, 92 parts by mass of methylene chloride and 8 parts by mass of methanol were charged and heated. While stirring, a retardation increasing agent solution was prepared. A dope was prepared by mixing 34 parts by mass of the retardation increasing agent solution with 474 parts by mass of the cellulose acetate solution and stirring sufficiently.

  The obtained dope was cast using a band stretching machine. After the film surface temperature on the band reached 40 ° C., the film was dried with warm air of 70 ° C. for 1 minute, and the film was peeled off from the band with a residual solvent of 30 mass%. Thereafter, the film was held with a tenter clip, and stretched equally to the left and right, and then dried for 10 minutes with 140 ° C. drying air to prepare a cellulose acetate film (thickness: 80 μm) having a residual solvent amount of 0.3 mass%. The produced cellulose acetate film had an in-plane retardation Re (550) of 8 nm and a thickness direction retardation Rth (550) of 95 nm. This film was used as the optically anisotropic layer C.

(Formation of alignment film)
An alignment film was formed in the same manner as in Example 1.

(Preparation of optically anisotropic layer B (rod-like liquid crystal composition layer))
An optically anisotropic layer B was formed in the same manner as in Example 1 using a coating liquid containing a rod-like liquid crystal compound having the following composition.
Composition of coating solution for optically anisotropic layer B ――――――――――――――――――――――――――――――――――
Said rod-like liquid crystalline compound 100 parts by mass photopolymerization initiator 3 parts by mass (Exemplary Compound 1 described in JP-A-2006-285187)
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The above fluoropolymer (D) 0.4 part by mass The above horizontal alignment agent 0.2 part by mass Methyl ethyl ketone 243 parts by mass ――――――――――――――――――――――――――――

  When the optical properties of the optically anisotropic layer B formed on the glass substrate were measured by the same method as described above, the in-plane retardation Re (550) at a wavelength of 550 nm was 81 nm. The calculated average inclination angle was 0 °. This layer was used as the optically anisotropic layer B.

(Formation of alignment film)
An alignment film forming coating solution having the following composition was adjusted with potassium hydroxide so as to have a pH of 10.0. The alignment film coating solution was applied at 20 ml / m ² with a wire bar coater. The alignment film was obtained by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, rubbing treatment was performed in a direction orthogonal to the slow axis of the optically anisotropic layer B.
(Composition of alignment film coating solution)
―――――――――――――――――――――――――――――――――
Denatured polyvinyl alcohol 20 parts by weight Potassium hydroxide 0.05 parts by weight Glutaraldehyde 0.5 parts by weight Water 360 parts by weight Methanol 120 parts by weight ――――――――――――――――――― ――――――――――――――

(Preparation of optically anisotropic layer A (rod-like liquid crystal composition layer))
Composition of optically anisotropic layer A ――――――――――――――――――――――――――――――――――――
43.72 parts by mass of rod-like liquid crystalline compound A1 having the following two acrylate groups 1.36 parts by mass of rod-like liquid crystalline compound A2 having the following two acrylate groups Polymer A (JP 2007-121996 Exemplified Compound P-15) 0. 01 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by mass Methyl ethyl ketone 252 parts by mass ―――――――――――――――――――――――――――――――

This coating solution was applied to the surface of the alignment film with a # 3.0 wire bar. This was heated in a constant temperature bath at 70 ° C. for 1.5 minutes to align the rod-like liquid crystal compound. Next, UV irradiation was performed at 60 ° C. with a 120 W / cm high-pressure mercury lamp for 20 seconds to crosslink the rod-like liquid crystalline compound, and then allowed to cool to room temperature to prepare an optically anisotropic layer.
When the optical characteristics of the optically anisotropic layer A formed on the glass substrate by the same method were measured, the in-plane retardation Re (550) at a wavelength of 550 nm was 88 nm. The calculated average inclination angle was 11 °.

Thus, the optical compensation film of Example 2 was produced. A polarizing plate and a TN mode liquid crystal display device were prepared and evaluated in the same manner as described above except that the optical compensation film of Example 1 was replaced with this optical compensation film. The slow axis of the optically anisotropic layer C and the absorption axis of the adjacent polarizing layer were arranged to be orthogonal.
The evaluation results and the like are shown in the table described later.

3. Example 3
(Preparation of optically anisotropic layer C)
The following cellulose acylate was heated to 120 ° C. and dried to adjust the water content to 0.5% by mass or less, and then 15 parts by mass was used.
1) Preparation of cellulose acylate solution:
A cellulose acetate powder having a substitution degree of 2.85 was used. Cellulose acylate A has a viscosity average degree of polymerization of 300, an acetyl group substitution degree at the 6-position of 0.89, an acetone extract of 7% by mass, a mass average molecular weight / number average molecular weight ratio of 2.3, and a water content of 0.3. Viscosity in 2 mass% and 6 mass% dichloromethane solutions is 305 mPa · s, residual acetic acid content is 0.1 mass% or less, Ca content is 65 ppm, Mg content is 26 ppm, iron content is 0.8 ppm, sulfate ion The content was 18 ppm, the yellow index was 1.9, and the amount of free acetic acid was 47 ppm. The average particle diameter of the powder was 1.5 mm, and the standard deviation was 0.5 mm.
2) Solvent:
A mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used. The water content of the solvent was 0.2% by mass or less.

3) Additive:
0.08 parts by mass of silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) were used. Moreover, the additive shown below was mixed so that it might become 5 mass parts, and dope for film forming was prepared.

4) Swelling and dissolution:
・ Dissolution process A
The cellulose acylate was gradually added to the 400 liter stainless steel dissolution tank having stirring blades and circulating cooling water around the outer periphery, while stirring and dispersing the solvent and additive. 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 the 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 [4.9 × 10 ⁵ N / m / sec ² ]). And an agitation shaft having an anchor blade on the central axis and stirring at a peripheral speed of 1 m / sec (shear stress 1 × 10 ⁴ kgf / m / sec ² [9.8 × 10 ⁴ N / m / sec ² ]) It was. 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.
The swollen solution was heated from a tank to 50 ° C. with a jacketed pipe, and further heated to 90 ° C. under a pressure of 2 MPa to be completely dissolved. The heating time was 15 minutes. At this time, filters, housings, and pipes that were exposed to high temperature were made of Hastelloy alloy and had excellent corrosion resistance, and those having a jacket for circulating a heat medium for heat retention and heating were used.
Next, the temperature was lowered to 36 ° C. to obtain a cellulose acylate solution.

5) Filtration The obtained solution was filtered with a filter paper (# 63, manufactured by Toyo Roshi Kaisha, Ltd.) having an absolute filtration accuracy of 10 μm, and further filtered to a sintered metal filter (FH025, manufactured by Pall) with an absolute filtration accuracy of 2.5 μm. And filtered to obtain a cellulose acylate solution.

6) Production of 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 50 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 end point of the casting 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 transparent film of cellulose acylate having a thickness of 80 μm.

7) Heat treatment:
The resulting film was heat treated using an apparatus having a heating zone between two nip rolls. The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, the heating zone was set to the temperature and heat treatment time shown in Table 1, and after passing through the two nip rolls, the film was 1000 ° C./min. Cooled to 25 ° C.
The produced cellulose acetate film had an in-plane retardation Re (550) of 55 nm and a thickness direction retardation Rth (550) of 83 nm. This was used as the optically anisotropic layer C.

(Preparation of optically anisotropic layer B)
An optically anisotropic layer B was formed in the same manner as in Example 1 using a coating liquid containing a rod-like liquid crystal compound having the following composition.
Composition of coating solution for optically anisotropic layer B ――――――――――――――――――――――――――――――――――
Said rod-like liquid crystalline compound 100 parts by mass photopolymerization initiator 3 parts by mass (Exemplary Compound 1 described in JP-A-2006-285187)
0.4 parts by weight of the above-mentioned fluoropolymer (D) 0.2 parts by weight of the above horizontal alignment agent 201 parts by weight of methyl ethyl ketone ――――――――――――――――――――――― ――――――――――
When the optical properties of the optically anisotropic layer B formed on the glass substrate were measured by the same method, the in-plane retardation Re (550) at a wavelength of 550 nm was 92 nm. The calculated average inclination angle was 0 °. This was used as the optically anisotropic layer B.

(Formation of alignment film)
An alignment film was prepared in the same manner as in Example 1.
(Preparation of optically anisotropic layer A)
On the alignment film, a liquid crystal composition having the following composition was applied with a # 2 wire bar. This was affixed to a metal frame and heated in a constant temperature bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, using a 120 W / cm high-pressure mercury lamp at 100 ° C., UV irradiation was performed for 30 seconds to crosslink the rod-like liquid crystal compound. Then, it stood to cool to room temperature, and produced the optically anisotropic layer A.
Liquid crystal composition ―――――――――――――――――――――――――――――――――
The above rod-shaped liquid crystal compound 18 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.54 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.18 parts by mass Air interface side tilt Control agent (Exemplary compound AD-22) 0.19 parts by mass Methyl ethyl ketone 208 parts by mass ――――――――――――――――――――――――――――――― -

  When the optical characteristics of the optically anisotropic layer A formed on the glass substrate were measured by the same method, the in-plane retardation Re (550) at a wavelength of 550 nm was 56 nm. The calculated average inclination angle was 35 °. This was used as the optically anisotropic layer A.

Thus, the optical compensation film of Example 3 was produced. A polarizing plate and a TN mode liquid crystal display device were prepared and evaluated in the same manner as described above except that the optical compensation film of Example 1 was replaced with this optical compensation film.
The evaluation results are shown in the following table.

4). Comparative Example 1
In Example 2, a TN mode liquid crystal display device was produced and evaluated in the same manner as in Example 2 except that the arrangement of the optically anisotropic layer A was changed as shown in the following table.
The evaluation results are shown in the following table.

5. Comparative Example 2
A TN mode liquid crystal display device was produced in the same manner as in Example 3 except that the arrangement of the optically anisotropic layer A was changed as shown in the following table, and was similarly evaluated.
The evaluation results are shown in the following table.

Evaluation was performed as follows.
[Evaluation of TN mode liquid crystal display]
-Viewing angle of upper, lower, left and right About the liquid crystal display devices produced in Examples 1 to 3 and Comparative Examples 1 and 2, black display (L0) and white display were performed using a measuring instrument "EZ-Contrast 160D" (manufactured by ELDIM) The viewing angle was measured at (L7). A region having a contrast ratio (white transmittance / black transmittance) of 10 or more was obtained as a viewing angle in the vertical and horizontal directions. Evaluation was made according to the following criteria. The results are shown in the table below.
When the total of the upper, lower, left, and right viewing angles for achieving a contrast of 10 or more is 320 ° or more, the display characteristics are practically excellent.
Evaluation ◎: Total of angles for which upper, lower, left, and right CR> 10 is 320 ° or more.

  In the above two tables, the sign of Re of the optically anisotropic layer is positive: the slow axis of the optically anisotropic layer is orthogonal to the adjacent polarizing plate absorption axis; the sign of Re of the optically anisotropic layer is negative: optical It means that the slow axis of the anisotropic layer is parallel to the adjacent polarizing plate absorption axis. Further, in the above two tables, for the sake of simplicity, the orientation of the optically anisotropic layer that is not inclined is described as “45 °” for 45-225 ° and “135 °” for 135-315 °.

6). Examples 4-13
In Example 1 and Example 3, the Re value and the average inclination angle were obtained by changing the amounts of the fluorine-based surfactant, exemplary compound AD-22, wire bar #, and methyl ethyl ketone used for forming the optically anisotropic layer A. Formed different optically anisotropic layers. An optical compensation film, a polarizing plate, and a TN mode liquid crystal display device were produced in the same manner except that the optically anisotropic layer A was replaced with these layers, and evaluated in the same manner. The results are shown in the table below.

7). Example 14
(Preparation of optically anisotropic layer C)
A film having a thickness of 80 μm was prepared and used as the optically anisotropic layer C with reference to the formulation and preparation method of the film 18 described in JP-A-2008-3126.
The in-plane retardation Re (550) of the produced film for the optically anisotropic layer C was 48 nm, and the retardation Rth (550) in the thickness direction was 117 nm (in addition, the measurement of JP-A-2008-3126) Because the wavelength and the measurement wavelength in this case are different, they are not the same value.)

(Preparation of optically anisotropic layer B)
An optically anisotropic layer B was formed in the same manner as in Example 1 except that methyl ethyl ketone in the composition of the coating liquid for forming the optically anisotropic layer B of Example 1 was changed to 298 parts by mass.
When the optical properties of the optically anisotropic layer B formed on the glass substrate were measured by the same method, the in-plane retardation Re (550) at a wavelength of 550 nm was 70 nm. The calculated average inclination angle was 0 °.

(Preparation of optically anisotropic layer A)
A coating liquid containing a rod-like liquid crystal compound having the following composition was continuously applied onto the alignment film with a # 2.0 wire bar. In order to dry the solvent of the coating solution and to mature the alignment of the rod-like liquid crystal compound, the coating liquid was heated for 60 seconds with hot air at 90 ° C. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form an optically anisotropic layer. This was used as the optically anisotropic layer A.
Composition of optically anisotropic layer A ――――――――――――――――――――――――――――――――――
Said rod-like liquid crystalline compound 100 parts by mass photopolymerization initiator 3 parts by mass (Exemplary Compound 1 described in JP-A-2006-285187)
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Fluoropolymer (D) 0.1 part by weight Methyl ethyl ketone 172 parts by weight ――――――――――――――― ――――――――――――――――――

  When the optical property of the optically anisotropic layer A formed on the glass substrate was measured by the same method, the in-plane retardation Re (550) at a wavelength of 550 nm was 52 nm. The calculated average inclination angle was 47 °.

  In this manner, an optical compensation film of Example 14 was produced. A polarizing plate and a TN mode liquid crystal display device were produced and evaluated in the same manner as in Example 1 except that this optical compensation film was used instead of the optical compensation film of Example 1. The evaluation result of the CR viewing angle was ◎.

8). Example 15
An optically anisotropic layer B was prepared with reference to the prescription / preparation method of Example 109 of JP2007-276455A. The optically anisotropic layer B thus produced had an in-plane retardation Re (550) of 70 nm and a thickness direction retardation Rth (550) of 35 nm.
An optical compensation film, a polarizing plate, and a TN mode liquid crystal display device were produced and evaluated in the same manner as in Example 14 except that this optically anisotropic layer B was used. The evaluation result of the CR viewing angle was ◎.

9. Example 16
For the optically anisotropic layer C, a film made of a commercially available norbornene polymer film “ZEONOR” (Nippon ZEON) is fixed at 140 ° C. and stretched 30% in the transverse direction. It was. This film for optically anisotropic layer C had Re of 52 nm and Rth of 118 nm. When Re (450) / Re (550) was calculated, it was almost flat dispersion.
An optical compensation film, a polarizing plate, and a TN mode liquid crystal display device were prepared and evaluated in the same manner as in Example 14 except that this optically anisotropic layer C was used. The evaluation result of the CR viewing angle was ◎.
Further, it was confirmed that the liquid crystal display device of Example 16 had less change in the CR viewing angle of black display with respect to the environmental change than the liquid crystal display device of Example 14. This is presumably because the film used for the optically anisotropic layer C has good moisture resistance.

10. Example 17
The cellulose acylate solution was prepared by mixing each component so as to have the ratio described below. Each cellulose acylate solution was cast using a band casting machine, the obtained web was peeled from the band, and then stretched 26% in the TD direction under the condition of 140 ° C. The TD direction means a direction perpendicular to the transport direction. After stretching, the film was dried to obtain a 40 μm optical film. This film was used as the optically anisotropic layer C.
(Cellulose acylate solution)
Cellulose acylate having an acetyl substitution degree of 1.54 and a propionyl substitution degree of 0.84
100 parts by mass The following additives K-1 5 parts by mass The following additives K-2 4 parts by mass Methylene chloride 416 parts by mass Ethanol 79 parts by mass

The produced film for optically anisotropic layer C had Re of 48 nm and Rth of 117 nm. Re (450) / Re (550) <1, and it was inverse dispersion.
An optical compensation film, a polarizing plate, and a TN mode liquid crystal display device were produced and evaluated in the same manner as in Example 14 except that this film was used as the optically anisotropic layer C. The evaluation result of the CR viewing angle was ◎.
Further, it was confirmed that the liquid crystal display device of Example 17 had less change in the CR viewing angle of black display with respect to the environmental change than the liquid crystal display device of Example 14. This is presumably because the film used for the optically anisotropic layer C has good moisture resistance.
Furthermore, it was confirmed that the liquid crystal display device of Example 17 had less color change in the oblique direction with respect to the front in black display than the liquid crystal display device of Example 14. This is presumably because a film having a reverse dispersion of Re is used as the film for the optically anisotropic layer C.

11. Examples 18-20
(1) Preparation example of cellulose acylate film (Preparation of cellulose acylate)
Cellulose acylate was synthesized by the method described in JP-A-10-45804 and 08-231761, and the degree of substitution was measured. Specifically, sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) was added as a catalyst, carboxylic acid serving as a raw material for the acyl substituent was added, and an acylation reaction was performed at 40 ° C. At this time, the kind and substitution degree of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid. In addition, aging was performed at 40 ° C. after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.

(Preparation of cellulose acylate solutions “C01” to “C03”)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution. The amount of the solvent (methylene chloride and methanol) was appropriately adjusted so that the solid content concentration of each cellulose acylate solution had the value described in the following Table **.
―――――――――――――――――――――――――――――――――――
-100.0 parts by mass of cellulose acetate having the substitution degree described in the following table-Additives described in the following table-Amounts described in the following table-365.5 parts by mass of methylene chloride-54.6 parts by mass of methanol ――――――――――――――――――――――――――――――
As shown in the table below, the cellulose acylate solution for other low-substituted layers is the same as “C01” except that the acyl group type and substitution degree of cellulose acylate, the amount of additive and additive type are changed. Was prepared. The solid content concentration and viscosity of the obtained cellulose acylate solution for the low substitution layer are shown in the following table.

＊１：化合物Ａはテレフタル酸／コハク酸／プロピレンクリコール／エチレングリコール共重合体（共重合比[モル％]＝２７．５／２２．５／２５／２５）を表す。なお、化合物Ａは非リン酸エステル系の化合物であり、かつ、レターデーション発現剤でもある。化合物Ａの末端はアセチル基で封止されている。
＊２：化合物Bは、下記に示す化合物Ａ−１９である。

* 1: Compound A represents a terephthalic acid / succinic acid / propylene glycol / ethylene glycol copolymer (copolymerization ratio [mol%] = 27.5 / 22.5 / 25/25). Compound A is a non-phosphate ester compound and a retardation developer. The end of compound A is sealed with an acetyl group.
* 2: Compound B is Compound A-19 shown below.

(Preparation of cellulose acylate solution “S01” for high substitution layer)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution. The amount of the solvent (methylene chloride and methanol) was appropriately adjusted so that the solid content concentration of each cellulose acylate solution had the value described in the following Table **.
―――――――――――――――――――――――――――――――――――
Cellulose acetate (substitution degree 2.81) 100.0 parts by mass Compound A 11 parts by mass Triphenyl phosphate 6.0 parts by mass Diphenylbiphenyl phosphate 5.0 parts by mass Silica fine particles R972 (manufactured by Nippon Aerosil) 0 15 parts by mass, methylene chloride 395.0 parts by mass, methanol 59.0 parts by mass ――――――――――――――――――――――――――――――― ――――

(Production of cellulose acylate film)
The cellulose acylate solution for a high substitution degree layer prepared above is a film described in the following table so that each cellulose acylate solution for a low substitution degree layer prepared above becomes a core layer having a film thickness described in the following table. Casting was performed so as to form a thick skin A layer and a skin B layer.
The obtained web (film) was peeled from the band, dried and wound up. At this time, the residual solvent amount with respect to the mass of the entire film was 0 to 0.5%. Then, the said film was sent out and TD (method orthogonal to a conveyance direction) extending | stretching was performed with the tenter on the conditions shown in the following table | surface. Furthermore, MD (conveying direction) stretching was performed by making the peripheral speed of the nip roll on the outlet side faster than the peripheral speed of the nip roll on the inlet side while heating between the two pairs of nip rolls. At this time, the speed of the two nip rolls was adjusted so that the draw ratio shown in the following table was obtained.
The residual solvent amount was determined according to the following formula.
Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is a mass of the web at an arbitrary time point, and N is a mass when the web of which M is measured is dried at 120 ° C. for 2 hours.
Thus, films 1 to 3 were produced.

  The optical properties of the produced films 1 to 3 are summarized in the following table.

(Formation of alignment film)
An alignment film coating solution having the following composition was continuously applied with a # 14 wire bar to the saponified surface of the film 1 produced above. 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. The formed film was continuously rubbed.
(Composition of alignment film coating solution)
――――――――――――――――――――――――――
Denatured polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight ―――――――――――――――――――――――――

(Formation of optically anisotropic layer B (rod-like liquid crystal compound))
A coating solution containing a rod-like liquid crystal compound having the following composition was continuously applied onto the alignment film with a # 8 wire bar. In order to dry the solvent of the coating solution and to mature the alignment of the rod-like liquid crystal compound, the coating liquid was heated for 60 seconds with hot air at 90 ° C. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation, and an optically anisotropic layer B was formed.
Composition of coating solution for optically anisotropic layer B ――――――――――――――――――――――――――――――――――
The following rod-like liquid crystalline compound 100 parts by mass photopolymerization initiator (Exemplary Compound 1 shown below) 3 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following fluoropolymer (D) 0.4 parts by mass The following horizontal alignment agent 0.2 parts by mass methyl ethyl ketone 120 parts by mass ------------- -

(Measurement of optical properties)
An optically anisotropic layer B formed on the glass substrate by the same method was subjected to an in-plane retardation Re (550 nm) with a wavelength of 550 nm using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). ) Was measured, the in-plane retardation Re (550) was 251 nm. Further, in the optically anisotropic layer B, the average tilt angle of the long axis of the rod-like liquid crystal with respect to the film surface is 0 °, and the fact that the rod-like liquid crystal is oriented horizontally with respect to the film surface is relative to the film normal direction. From the normal direction to 50 degrees on one side in 10 degree steps, light with a wavelength of 550 nm is incident from each inclined direction, and a total of 6 points are measured. The measured retardation value and assumed value of average refractive index and input Based on the measured film thickness value, it was confirmed from KOBRA 21ADH.

(Formation of alignment film)
An alignment film was formed in the same manner as the alignment film used when forming the optically anisotropic layer B. At this time, rubbing treatment was performed in a direction orthogonal to the slow axis of the optically anisotropic layer B.

(Formation of optically anisotropic layer A (rod-like liquid crystal compound))
A coating solution having the following composition was prepared.
Composition of optically anisotropic layer A ――――――――――――――――――――――――――――――――――――
The following rod-shaped liquid crystal compound 18 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.54 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.18 parts by mass Air interface side tilt Control agent (compound AD-22 below) 0.18 parts by mass Methyl ethyl ketone 57 parts by mass ――――――――――――――――――――――――――――――― ――――

  This coating solution was applied to the surface of the alignment film with a # 2 wire bar. This was affixed to a metal frame and heated in a constant temperature bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, using a 120 W / cm high-pressure mercury lamp at 100 ° C., UV irradiation was performed for 30 seconds to crosslink the rod-like liquid crystal compound. Then, it stood to cool to room temperature, and produced the optically anisotropic layer A.

(Measurement of optical properties)
An optically anisotropic layer A formed on a glass substrate by the same method was used for an in-plane retardation Re (550 nm) having a wavelength of 550 nm using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). ) Was measured, the in-plane retardation Re (550) was 83 nm. Further, in the optically anisotropic layer A, the average tilt angle with respect to the film surface of the long axis of the rod-like liquid crystal was 29 °.

  Using the produced optical compensation film, a polarizing plate and a liquid crystal display device were produced in the same manner as in Example 1, and the CR viewing angle evaluation and the following frame-shaped light leakage evaluation were performed in the same manner (Example). 18).

  Optical compensation films were produced in the same manner as in Example 18 except that the film 1 was replaced with the films 2 and 3, respectively. Furthermore, using each optical compensation film, a polarizing plate and a liquid crystal display device were produced in the same manner as in Example 1, and the following frame-shaped light leakage evaluation was performed (Examples 19 and 20).

(Evaluation of frame-shaped light leakage)
Each liquid crystal display device prepared above was dried at 70 ° C. and placed in a drier for 170 hours and then taken out. The entire liquid crystal display device was in a black display state and visually observed in a dark room to evaluate light leakage.
A: Little light leakage was observed around the polarizing plate (no problem in practical use).
○: Light leakage was observed around the polarizing plate, but there was no practical problem.
X: Light leakage is observed around the polarizing plate, which is problematic in practice.
The evaluation results are shown in the following table.

  From the results shown in the above table, it can be understood that Examples 18 to 20, which are examples of the present invention, all have good CR viewing angle evaluation results. In particular, Examples 18 and 19 using a low-substituted cellulose acylate film as the optically anisotropic layer C used a film mainly composed of a high-substituted cellulose acylate as the optically anisotropic layer C. Compared with Example 20, it can be understood that frame-shaped light leakage during black display is reduced, and that display characteristics are excellent from this viewpoint.

1 Liquid crystal layer 2, 3 Cell substrate 4, 5 Polarizer 6, 6 ′, 6 ″, 6 ″ ″ Optically anisotropic layer A
7, 7 'Optically anisotropic layer B
8, 8 'Optically anisotropic layer C
DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 12, 14 Optically anisotropic laminated body LCD1 Liquid crystal display device LCD2 Liquid crystal display device LCD3 Liquid crystal display device LCD4 Liquid crystal display device

Claims (9)

First and second polarizing films arranged with their absorption axes orthogonal to each other,
First and second cell substrates disposed between the first and second polarizing films (however, the first cell substrate is disposed closer to the first polarizing film, and the second And a liquid crystal cell in a twisted alignment mode having at least a liquid crystal layer disposed therebetween, and the first polarizing film and the liquid crystal. First and second optics having at least three optically anisotropic layers, optically anisotropic layers A, B, and C, respectively, between the cells and between the second polarizing film and the liquid crystal cell. A liquid crystal display device having an anisotropic laminate,
From the liquid crystal cell side, the optically anisotropic layer A, the optically anisotropic layer B, and the optically anisotropic layer C are arranged in this order, and the optically anisotropic layer in the second optically anisotropic laminate is disposed. The optical axis of A and the optical axis of the liquid crystal layer in the second cell substrate are antiparallel to each other;
Wherein each of the first and second optically anisotropic laminate before Symbol optical anisotropic layer A, the order of arrangement of B and C, are symmetrical about the liquid crystal cell,
The optically anisotropic layer A contains a rod-like liquid crystal fixed in an inclined alignment state, and the in-plane retardation at a wavelength of 550 nm is 0 to 200 nm,
The sum of in-plane retardations of the optically anisotropic layers B and C is 0 to 300 nm, the in-plane slow axis of the optically anisotropic layer B in the first optically anisotropic laminate, and the The absorption axis with the first polarizing film is parallel or orthogonal, and the in-plane slow axis of the optically anisotropic layer B in the second optically anisotropic laminate and the second polarizing film The absorption axes of are parallel or orthogonal;
The axes obtained by projecting the optical axis of the optically anisotropic layer A in the first optically anisotropic laminated body and the optical axis of the first cell substrate of the liquid crystal layer in the same plane are antiparallel to each other. And the axes obtained by projecting the optical axis of the optically anisotropic layer A in the second optically anisotropic laminate and the optical axis of the second cell substrate of the liquid crystal layer in the same plane are mutually A twisted alignment mode liquid crystal display device that is antiparallel or orthogonal. The twisted alignment mode liquid crystal display device according to claim 1 , wherein an average inclination angle of the rod-like liquid crystal of the optically anisotropic layer A is 10 to 85 °. The in-plane retardation of the optically anisotropic layer A, twisted alignment mode liquid crystal display device according to claim 1 or 2 is 0～150Nm. The in-plane retardation of the optically anisotropic layer C is 0 to 300 nm, the retardation in the thickness direction is -200 to 300 nm, and the in-plane retardation of the optically anisotropic layer B is 0 to 300 nm. The twisted alignment mode liquid crystal display device according to any one of 1 to 3 . Optically anisotropic layer B is, contains a rod-like liquid crystal fixed to the inclined orientation of the average inclination angle of 30 ° or less or 75 to 90 °, any of claims 1 to 4, the in-plane retardation is 0~200nm 2. A twisted alignment mode liquid crystal display device according to item 1. 5. The twisted alignment mode liquid crystal display device according to claim 1, wherein the optically anisotropic layer B contains a rod-like liquid crystal fixed in an alignment state having an average inclination angle of substantially 0 °. The twisted alignment mode liquid crystal display according to any one of claims 1 to 5 , wherein the optically anisotropic layer B is a polymer film, the in-plane retardation is 0 to 300 nm, and the retardation in the thickness direction is 0 to 250 nm. apparatus. The optically anisotropic layer C, cyclic olefin copolymers, cellulose acylate, polyesters, polycarbonates, in claim 4, characterized in that it consists of a film containing at least one selected from acrylates The twisted alignment mode liquid crystal display device described. The twisted alignment mode liquid crystal display device according to claim 4 , wherein the optically anisotropic layer C is a stretched film.

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