JP2008033285A - Retardation film, polarizing plate and liquid crystal display device - Google Patents

Abstract

A retardation film and the like capable of improving light leakage and color change when viewed from an oblique direction in black display.
A retardation film having a support and at least one optically anisotropic layer, the front retardation Re and the retardation Rth in the thickness direction of the support satisfy the following formula [1], The wavelength dispersion of the support satisfies the following formula [2], the support is made of a cellulose acylate film, and the front retardation Re and the retardation Rth in the thickness direction of the retardation film are expressed by the following formula [3]. And the retardation film satisfies the following formula [4].
[1] 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
[2] | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[3] 0 ≦ Re (550) ≦ 10 and 100 ≦ Rth (550) ≦ 300
[4] 1.04 ≦ Rth (450) / Rth (550) ≦ 1.30
[In the formula, Re (λ) is represented by Re (λ) = (nx−ny) × d, and represents a front retardation value (unit: nm) at a wavelength of λ nm. Rth (λ) is represented by Rth (λ) = {(nx + ny) / 2−nz} × d, and represents the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film refractive index. Thickness (nm). ]
[Selection figure] None

Description

  The present invention relates to the technical fields of retardation films, polarizing plates and liquid crystal display devices, and more particularly to vertical alignment type liquid crystal display devices and the like.

  A liquid crystal display device usually has a liquid crystal cell and a polarizing plate. The polarizing plate has a protective film and a polarizing film. The polarizing plate is obtained, for example, by dyeing a polarizing film made of a polyvinyl alcohol film with iodine, stretching, and laminating protective films on both surfaces thereof. In the transmissive liquid crystal display device, the polarizing plate is attached to both sides of the liquid crystal cell, and one or more optical compensation sheets may be disposed. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, one or more optical compensation sheets, and a polarizing plate are arranged in this order. The liquid crystal cell includes a liquid crystal molecule, two substrates for encapsulating the liquid crystal molecule, and an electrode layer for applying a voltage to the liquid crystal molecule. The liquid crystal cell displays ON and OFF depending on the alignment state of liquid crystal molecules, and can be applied to both transmission and reflection types. TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensatory Bend) Display modes such as VA (Vertically Aligned) and ECB (Electrically Controlled Birefringence) have been proposed.

  Among such liquid crystal display devices, for applications that require high display quality, a 90-degree twisted nematic liquid crystal display device (hereinafter referred to as TN) driven by thin film transistors using nematic liquid crystal molecules having positive dielectric anisotropy. Mode) is mainly used. However, although the TN mode has excellent display characteristics when viewed from the front, the contrast is reduced when viewed from an oblique direction, or gradation inversion that reverses the brightness in gradation display occurs. There is a viewing angle characteristic that the display characteristic is deteriorated, and this improvement is strongly demanded.

  Recently, nematic liquid crystal molecules having negative dielectric anisotropy are used as a liquid crystal display system for improving the viewing angle characteristics, and the major axis of the liquid crystal molecules is set in a direction substantially perpendicular to the substrate without applying a voltage. A vertical alignment nematic liquid crystal display device (hereinafter referred to as VA mode) in which alignment is performed and driven by a thin film transistor has been proposed (see Patent Document 1). This VA mode not only has excellent display characteristics when viewed from the front, but also exhibits a wide viewing angle characteristic by applying a viewing angle compensation phase difference film. In the VA mode, a wide viewing angle characteristic can be obtained by using two negative uniaxial retardation films having an optical axis in a direction perpendicular to the film surface, above and below the liquid crystal cell. Furthermore, it is also known that a wider viewing angle characteristic can be realized by using a uniaxially oriented retardation film having a positive refractive index anisotropy with an in-plane retardation value of 50 nm (Non-patent Document 1). reference).

  However, increasing the number of retardation films increases the production cost, and tends to cause a decrease in yield because a large number of films are bonded together. Furthermore, since a plurality of films are used, the thickness increases, which may be disadvantageous for thinning the display device. Moreover, since an adhesive layer is used for lamination | stacking of a stretched film, an adhesive layer shrink | contracts by a temperature / humidity change, and defects, such as peeling and curvature between films, may generate | occur | produce.

  As a method for improving these, a method for reducing the number of retardation films (see Patent Document 2) and a method using a cholesteric liquid crystal layer (see Patent Document 3) are disclosed. However, even in these methods, it is necessary to attach at least a plurality of films, which is insufficient in terms of thinning the liquid crystal display device and reducing production costs.

Further, for the purpose of improving the above problems, a method using a discotic liquid crystalline compound (see Patent Document 4) has been proposed. However, in the method described in Patent Document 4, it is difficult to continuously form an optically anisotropic layer on a long support, and productivity is inferior. Furthermore, a method for solving this problem is disclosed in Patent Document 5 (see Patent Document 5). However, the method described in Patent Document 5 also has problems such as coating unevenness because the coating film thickness increases in order to obtain necessary optical characteristics (particularly, Rth value).
Furthermore, Patent Document 6 discloses a method for improving coating unevenness by employing an optically anisotropic layer having an absolute value of refractive index anisotropy in a specific range.
However, the above method is not at a level that can satisfy the display characteristics of the liquid crystal display.
Japanese Patent Laid-Open No. 2-176625 JP-A-11-95208 JP-A-11-95208 JP-A-11-352328 JP 2000-304931 A JP 2005-128050 A SID 97 DIGEST Pages 845-848

An object of the present invention is to provide a retardation film for use in a liquid crystal display device in which a liquid crystal cell is accurately optically compensated and can be dealt with even if the number of films to be bonded is reduced, that is, a thin layer can be formed. And a liquid crystal display device.
In particular, an object of the present invention is to provide a liquid crystal display device for use in a VA mode, and to improve light leakage and color change when viewed from an oblique direction in black display of the liquid crystal display device.

Under such a problem, as a result of inventor's earnest examination, as for the retardation film combining the conventional support and the optically anisotropic layer, all are paying attention to the characteristics of the optically anisotropic layer, The above-mentioned problem also lies in the point that the optical characteristics of the support cannot be said to be sufficient, and for this reason, it has been found that the display characteristics of the liquid crystal display device using the retardation film have not reached a satisfactory level. It was.
Specifically, the above problem has been solved by the following means.
(1) A retardation film having a support and at least one optically anisotropic layer, wherein the front retardation Re and the thickness direction retardation Rth of the support satisfy the following formula [1], The wavelength dispersion of the support satisfies the following formula [2], the support is made of a cellulose acylate film, and the front retardation Re and the thickness direction retardation Rth of the retardation film satisfy the following formula [3]. The retardation film satisfy | fills and the wavelength dispersion of the said retardation film satisfy | fills following formula [4].
[1] 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
[2] | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[3] 0 ≦ Re (550) ≦ 10 and 100 ≦ Rth (550) ≦ 300
[4] 1.04 ≦ Rth (450) / Rth (550) ≦ 1.30
[In the formula, Re (λ) is represented by Re (λ) = (nx−ny) × d, and represents a front retardation value (unit: nm) at a wavelength of λ nm. Rth (λ) is represented by Rth (λ) = {(nx + ny) / 2−nz} × d, and represents the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film refractive index. Thickness (nm). ]
(2) The retardation film according to (1), wherein the wavelength dispersibility of the retardation film satisfies the following formula [5].
[5] 1.06 ≦ Rth (450) / Rth (550) ≦ 1.30
(3) The retardation film according to (1) or (2), wherein at least one of the optically anisotropic layers contains a homeotropically oriented polymerizable discotic liquid crystalline compound.
(4) The retardation film according to (1) or (2), wherein at least one layer of the optically anisotropic layer contains a cholesteric-aligned polymerizable rod-like liquid crystal compound.
(5) The retardation film according to (1) or (2), wherein at least one layer of the optically anisotropic layer is composed of a polymer polymer or a polymer polymer further stretched after being laminated on the support.
(6) The retardation film according to any one of (1) to (5), wherein at least one of the optically anisotropic layers contains a fluorine-containing surfactant.
(7) In the cellulose acylate, the support is a cellulose acylate having an acyl substitution degree of 2.85 to 3.00, and at least one compound that reduces Re (λ) and / or Rth (λ). The retardation film according to any one of (1) to (6), which is obtained by adding at a ratio of 0.01 to 30% by mass.
(8) The retardation film according to any one of (1) to (7), wherein the support has a thickness of 10 to 120 μm.
(9) Polarized light having a polarizing film and protective films provided on both surfaces of the polarizing film, wherein at least one of the protective films is the retardation film according to any one of (1) to (8) Board.
(10) It has the retardation film according to any one of (1) to (8) and a second retardation film, and the front retardation and the thickness direction of the second retardation film. A polarizing plate in which retardation satisfies the following formula [6] and wavelength dispersion of the second retardation film satisfies the following formula [7].
[6] 70 ≦ Re (550) ≦ 180 and 30 ≦ Rth (550) ≦ 140
[7] 0.7 ≦ Re (450) / Re (550) ≦ 1.0
(11) A liquid crystal display device comprising the retardation film according to any one of (1) to (8) or the polarizing plate according to (9) or (10).
(12) Two polarizing plates whose absorption axes are orthogonal to each other, and a liquid crystal cell provided between the two polarizing plates, wherein the liquid crystal cell includes a pair of substrates and a pair of the substrates And in a non-driving state in which no external electric field is applied, the liquid crystal molecules are aligned in a direction substantially perpendicular to the pair of substrates. A liquid crystal display device comprising the retardation film according to any one of (1) to (8) or wherein the polarizing plate is the polarizing plate according to (9) or (10).
(13) The liquid crystal display device further includes a second retardation film, the second retardation film is composed of a polymer stretched film, and the front retardation and the retardation in the thickness direction are represented by the following formula [6 ] The liquid crystal display device according to (11) or (12).
[6] 70 ≦ Re (550) ≦ 180 and 30 ≦ Rth (550) ≦ 140
(14) The liquid crystal display device further includes a second retardation film, and the wavelength dispersion of the second retardation film satisfies the following formula [7], and any one of (11) to (13) 2. A liquid crystal display device according to item 1.
[7] 0.7 ≦ Re (450) / Re (550) ≦ 1.0
(15) The liquid crystal display device further includes a second retardation film, and the second retardation film is a cellulose acylate film, a norbornene film, a polycarbonate film, a polyarylate film, or a polyester film. And the liquid crystal display device according to any one of (11) to (14), comprising any one of a polysulfone-based film.
(16) The liquid crystal display device further includes a second retardation film, and the second retardation film is directly laminated on one of the polarizing films in an arrangement in which the absorption axes of the polarizing films are orthogonal to each other. (11)-(15) The liquid crystal display device of any one of (15).

According to the present invention, an integrated polarizing plate can be produced. By using the retardation film of the present invention, a liquid crystal cell can be optically compensated with the same configuration as a conventional liquid crystal display device. It became possible.
In particular, it has become possible to achieve both an oblique leakage light and a color change at a high level in black display of the liquid crystal display device of the present invention.
Further, in the conventional liquid crystal display device, in order to incorporate the optical compensation sheet, a step of laminating while strictly adjusting the angles of the plurality of retardation films and the polarizing plate is necessary. However, in the present invention, it is not necessary to go through such steps, and it becomes possible to continuously form an optically anisotropic layer on a long support, and optical anisotropy without problems such as unevenness during coating. Formation of the layer became possible.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In addition, unless otherwise specified, the “substituent” such as an alkyl group in the present specification may further have a substituent or may not have a substituent.

  In this specification, “substantially” for the angle means that the error from the exact angle is within a range of less than ± 5 °. Furthermore, the error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In the present specification, “visible light” means light having a wavelength of 400 nm to 700 nm.

Re (λ) in the present invention is a front retardation value (unit: nm) at a wavelength λnm, and is represented by the following formula.
Re (λ) = (nx−ny) × d
(Where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is (The thickness of the film (nm).)

Further, Rth (λ) in the present invention is a retardation value (unit: nm) in the film thickness direction at a wavelength λnm, and is represented by the following formula.
Rth = ((nx + ny) / 2−nz) × d
(Where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is (The thickness of the film (nm).)

[Liquid Crystal Display]
First, an embodiment of the liquid crystal display device of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic view of an example of the structure of a polarizing plate that can be used in the present invention, and FIG. FIG. 1 shows an example in which active driving is performed using a nematic liquid crystal having negative dielectric anisotropy as a field effect liquid crystal element.

  In FIG. 1, the liquid crystal display device includes a liquid crystal cell and a pair of polarizing plates (an upper polarizing plate 1 and a lower polarizing plate 14) disposed on both sides of the liquid crystal cell. A second retardation film 3 is disposed between the upper polarizing plate 1 and the liquid crystal cell, and a first retardation film 10 is disposed between the lower polarizing plate 14 and the liquid crystal cell. The liquid crystal cell includes an upper electrode substrate 5, a lower electrode substrate 8, and liquid crystal molecules 7 sandwiched between them. The liquid crystal molecules 7 are aligned with respect to the substrate in an undriven state in which no external electric field is applied by the alignment control directions (upper substrate alignment control direction 6 and lower substrate alignment control direction 9) applied to the opposing surface of the electrode substrate. To be oriented in a substantially vertical direction. Further, the upper polarizing plate 1 and the lower polarizing plate 14 are laminated so that the absorption axis and the absorption axis are substantially orthogonal to each other. In FIG. 1, 2 represents the direction of the upper polarizing plate absorption axis, and 15 represents the direction of the lower polarizing plate absorption axis. Furthermore, the slow axis direction 4 of the second retardation film is provided so as to be orthogonal to the absorption axis direction 2 of the upper polarizing plate.

  As shown in FIG. 2, the polarizing plate includes a polarizing film 103 sandwiched between protective films 101 and 105. The polarizing plate can be produced, for example, by dyeing a polarizing film made of a polyvinyl alcohol film with iodine and stretching it to obtain a polarizing film, and laminating protective films 101 and 105 on both sides thereof. In the case of lamination, it is preferable in terms of productivity when a total of three films including a pair of protective films and a polarizing film are bonded together in a roll-to-roll manner. Further, in the roll-to-roll lamination, as shown in FIG. 2, the slow axis directions 102 and 106 of the protective film can be easily laminated so that the absorption axis direction 104 of the polarizing film is parallel. It is preferable because a dimensional change of the plate and occurrence of curling hardly occur and the polarizing plate has high mechanical stability. The same effect can be obtained if at least two axes of three films, for example, the slow axis and polarizing film absorption axis of one protective film or the slow axes of two protective films are substantially parallel. Is obtained.

  In FIG. 1, the second retardation film 3 is optically composed of a uniaxial or biaxial optically anisotropic layer, and is not particularly limited. However, cellulose acylate, norbornene polymer, polycarbonate polymer, Examples thereof include polyarylate polymers, polyester polymers, polysulfone, and polymers obtained by mixing two or more of these polymers. Among them, those excellent in controllability of birefringence characteristics, transparency and heat resistance are preferable. In addition, the second retardation film 3 depends on the combination with the first retardation film 10, but from the viewpoint of display characteristics, the absolute value of Re increases with the wavelength, so-called reverse wavelength dispersion. More preferably, it is uniaxial. On the other hand, the first retardation film 10 has optically negative refractive index anisotropy, and the absolute value of Rth decreases with the wavelength, so-called forward wavelength dispersion, and Re is −10 to 10 nm. It is preferable. The second retardation film 3 and the first retardation film 10 eliminate the image coloring of the liquid crystal cell and contribute to the expansion of the viewing angle.

  In FIG. 1, when the upper side is an observer side, in FIG. 1, the second retardation film 3 is an upper polarizing plate 1 on the observer side and an observer side liquid crystal cell substrate. 5, the first retardation film 10 is configured to be disposed between the lower polarizing plate 14 on the back side and the liquid crystal cell lower electrode substrate 8 which is the back side liquid crystal cell substrate. The second retardation film 3 and the first retardation film 10 may be interchanged, and both the second retardation film 3 and the first retardation film 10 It may be disposed between the plate 1 and the liquid crystal cell upper electrode substrate 5, or may be disposed between the lower polarizing plate 14 and the liquid crystal cell lower electrode substrate 8. In such an embodiment, the first retardation film 10 may also serve as a support for the second retardation film 3.

  The retardation film may be integrated with the polarizing plate. For example, in FIG. 1, the second retardation film 3 may be integrated with the upper polarizing plate 1. In this case, it can be incorporated into the liquid crystal display device in an integrated state with the upper polarizing plate 1. For example, the support for the second retardation film may function as a protective film on one side of the polarizing film, and the integrated polarizing plate in which the protective film, the polarizing film, and the second retardation film are laminated in this order It is preferable to do this. When the integrated polarizing plate is incorporated in the liquid crystal display device, it is preferable to incorporate the protective film, the polarizing film, and the second retardation film 3 in this order from the outside of the device (the side far from the liquid crystal cell). .

  The first retardation film 10 is a retardation film of the present invention having a support and an optically anisotropic layer. The retardation film of the present invention can be incorporated in a liquid crystal display device as an integrated polarizing plate integrated with the lower polarizing plate 14, as in the second retardation film 3. In an embodiment in which the optically anisotropic layer of the first retardation film is made of a liquid crystalline compound, the protective film on one side of the lower polarizing plate 14 is bonded to the polarizing film on the support surface opposite to the optically anisotropic layer. May also serve as a support for the first retardation film 10. In this embodiment, the integrated polarizing plate is laminated in the order of the protective film, the polarizing film, and the first retardation film 10, and the integrated polarizing plate is disposed from the outside (the side far from the liquid crystal cell) from the protective film, the polarizing film. The liquid crystal display device is preferably incorporated in the order of the first retardation film 10.

  The liquid crystal display device of the present invention is not limited to the above configuration, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. In the transmissive liquid crystal display device, a backlight using a cold or hot cathode fluorescent tube, a light emitting diode, or an electroluminescent element as a light source can be disposed on the back surface. On the other hand, in the aspect of the reflective liquid crystal display device, only one polarizing plate needs to be disposed on the observation side, and a reflective film is provided on the back surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side. Further, a transflective type in which a transmissive portion and a reflective portion are provided in one pixel of the display device is also possible.

  The type of the liquid crystal display device of the present invention is not particularly limited, and includes any of image direct view type, image projection type, and light modulation type liquid crystal display devices. An active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as TFT or MIM is particularly effective in the present invention. Of course, the present invention is also effective in a passive matrix liquid crystal display device represented by a super-twisted nematic type (STN type) called time-division driving.

[VA mode liquid crystal cell]
In the present invention, the liquid crystal cell is preferably in a vertically aligned mode (VA mode). In a VA mode liquid crystal cell, liquid crystal molecules are aligned in a direction substantially perpendicular to the substrate of the liquid crystal cell in a non-driven state where an external electric field is not applied. Such a liquid crystal cell is formed, for example, by enclosing liquid crystal molecules having negative dielectric anisotropy between upper and lower electrode substrates whose opposing surfaces are rubbed.
More specifically, using a liquid crystal molecule having Δn = 0.0813 and Δε = −4.6, a director indicating the alignment direction of the liquid crystal molecule, that is, a liquid crystal cell having a so-called tilt angle of about 89 ° can be manufactured. it can. At this time, the thickness d of the liquid crystal layer can be set to 3.5 μm, for example. The brightness at the time of white display changes depending on the magnitude of the product Δn · d of the thickness d (nm) of the liquid crystal layer and the refractive index anisotropy Δn. In order to obtain the maximum brightness, the thickness d of the liquid crystal layer is preferably in the range of 2 to 5 μm (2000 to 5000 nm), and Δn is preferably in the range of 0.060 to 0.085. .

Here, the refractive index anisotropy Δn is
Δn = Rth / film thickness (nm)
It is represented by

  A transparent electrode (not shown) is formed inside the liquid crystal cell upper electrode substrate 5 and the liquid crystal cell lower electrode substrate 8, but in a non-driving state in which a driving voltage is not applied to the electrodes, the liquid crystal molecules 7 in the liquid crystal layer. Are aligned substantially perpendicular to the substrate surface, and as a result, the polarization state of the light passing through the liquid crystal panel hardly changes. As described above, the direction 2 of the upper polarizing plate absorption axis of the liquid crystal cell and the direction 15 of the lower polarizing plate absorption axis are substantially orthogonal, so that light does not pass through the polarizing plate. That is, the liquid crystal display device of FIG. 1 realizes an ideal black display in the non-driven state. On the other hand, in the driving state, the liquid crystal molecules are inclined in a direction parallel to the substrate surface, and the light passing through the liquid crystal panel changes the polarization state by the inclined liquid crystal molecules and passes through the polarizing plate.

  In FIG. 1, since an electric field is applied between the upper and lower substrates, an example in which a liquid crystal material having a negative dielectric anisotropy in which liquid crystal molecules respond perpendicularly to the electric field direction is shown. In the case where an electrode is disposed on one substrate and an electric field is applied in a lateral direction parallel to the substrate surface, a liquid crystal material having a positive dielectric anisotropy can be used. In addition, in a VA mode liquid crystal display device, the addition of a chiral agent generally used in a twisted nematic mode (TN mode) liquid crystal display device is rarely used to degrade dynamic response characteristics, but poor alignment. It may be added to reduce the amount.

  The characteristics of the VA mode are high-speed response and high contrast. However, there is a problem that the contrast is high in the front but decreases in the oblique direction. During black display, the liquid crystal molecules are aligned perpendicular to the substrate surface. When observed from the front, the liquid crystal molecules have almost no birefringence, so the transmittance is low and a high contrast can be obtained. However, when observed obliquely, birefringence occurs in the liquid crystal molecules. Further, the crossing angle of the upper and lower polarizing plate absorption axes is 90 ° perpendicular to the front, but is larger than 90 ° when viewed from an oblique direction. Due to these two factors, leakage light tends to occur in the oblique direction, and the contrast tends to decrease. In the present invention, in order to solve this, the optically anisotropic layers 3 and 10 can be arranged at least one layer at a time.

  In the VA mode, the liquid crystal molecules are tilted during white display, but the birefringence of the liquid crystal molecules when viewed from an oblique direction is different between the tilt direction and the opposite direction, resulting in differences in luminance and color tone. In order to solve this, the liquid crystal cell is preferably multi-domain. Multi-domain refers to a structure in which a plurality of regions having different alignment states are formed in one pixel. For example, in a multi-domain type VA mode liquid crystal cell, a plurality of regions having different tilt angles of liquid crystal molecules when an electric field is applied exist in one pixel. In a multi-domain VA mode liquid crystal cell, the tilt angle of liquid crystal molecules due to application of an electric field can be averaged for each pixel, whereby the viewing angle characteristics can be averaged. In order to divide the orientation within one pixel, the electrode is provided with slits or protrusions, and the electric field direction is changed or the electric field density is biased. In order to obtain a uniform viewing angle in all directions, the number of divisions may be increased.

  Also, the liquid crystal molecules are difficult to respond at the alignment division region boundary. For this reason, in normally black display, since black display is maintained, a reduction in luminance becomes a problem. Adding a chiral agent to the liquid crystal material contributes to reducing the boundary region.

Hereinafter, the retardation film used in the liquid crystal display device of the present invention will be described in detail.
In the present invention, the optically anisotropic layer eliminates image coloring of the liquid crystal display device and contributes to the expansion of the viewing angle. In addition, when the support of the optically anisotropic layer also serves as a protective film for the polarizing plate, or the optically anisotropic layer also serves as a protective film for the polarizing plate, the number of constituent members of the liquid crystal display device can be reduced. . In other words, this aspect contributes to the thinning of the liquid crystal display device.

In the present invention, the first retardation film (the retardation film of the present invention) that combines a cellulose acylate film having a small absolute value of Re and Rth and an optically anisotropic layer significantly increases the optical characteristics of the liquid crystal display device. Can be improved. Specifically, the optical properties are so high that the front retardation of the support and the retardation Rth in the thickness direction satisfy the following formula [1], and the wavelength dispersion of the support satisfies the following formula [2]. A cellulose acylate film having a controlled viscosity is used. Further, by combining with an optically anisotropic layer, the retardation film of the present invention as a whole has front retardation Re and thickness direction retardation Rth satisfying the following formula [3], and wavelength dispersibility is represented by the following formula [ 4].
[1] 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
[2] | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[3] 0 ≦ Re (550) ≦ 10 and 100 ≦ Rth (550) ≦ 300
[4] 1.04 ≦ Rth (450) / Rth (550) ≦ 1.30

  The front retardation Re (550) of the retardation film of the present invention is preferably 8 nm or less, more preferably 5 nm or less, and further preferably 3 nm or less. The retardation Rth (550) in the thickness direction of the retardation film is preferably 120 to 280 nm, more preferably 140 to 260 nm, and still more preferably 160 to 240 nm. The wavelength dispersibility of the retardation film is preferably 1.06 to 1.30, more preferably 1.08 to 1.28 or less, and further preferably 1.10 to 1.26 nm or less. .

  In the present specification, 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). Rth (λ) is the above-mentioned Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) The light of wavelength λ nm is incident from each of the inclined directions in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction (with the direction of the rotation axis as the rotation axis). KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed average refractive index, and the input film thickness value. The retardation value is measured from any two 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), and the value Rth can also be calculated from the following formula (1) and the above based on the assumed value of the average refractive index and the input film thickness value. Here, as the assumed value of the average refractive index, the values in the 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. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). By inputting these assumed values of average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz.

注記：上記のRe(θ)は法線方向から角度θ傾斜した方向におけるレターデーション値を表す。
また、Ｒｔｈの符号は面内の遅相軸を傾斜軸（回転軸）としてフィルム法線方向に対して＋２０°傾斜した方向から波長５５０ｎｍの光を入射させて測定したレターデーションがＲｅを超える場合を正とし、Ｒｅを下回る場合を負とする。但し、｜Ｒｔｈ／Ｒｅ｜が９以上の試料では、回転自由台座付きの偏光顕微鏡を用いて、面内の進相軸を傾斜軸（回転軸）としてフィルム法線方向に対して＋４０°傾斜した状態で、偏光板の検板を用いて決定できる試料の遅相軸がフィルム平面に平行にある場合を正とし、また遅相軸がフィルムの厚み方向にある場合を負とする。

Note: Re (θ) above represents the retardation value in the direction inclined at an angle θ from the normal direction.
In addition, the sign of Rth is when the retardation measured by injecting light having a wavelength of 550 nm from the direction inclined + 20 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis) exceeds Re Is positive and negative is below Re. However, in the sample with | Rth / Re | of 9 or more, it was tilted by + 40 ° with respect to the film normal direction with the in-plane fast axis as the tilt axis (rotation axis) using a polarizing microscope with a free rotation base. In the state, the case where the slow axis of the sample which can be determined using the polarizing plate inspection plate is parallel to the film plane is positive, and the case where the slow axis is in the thickness direction of the film is negative.

[Support for first retardation film]
Cellulose acylate is used for the support of the retardation film of the present invention. Cellulose acylate is preferable from the viewpoint that it has no absorption in the visible light region, has a light transmittance of 80% or more, and has a small retardation based on birefringence. Furthermore, a cellulose acylate film is preferable from the viewpoint of being able to be directly bonded to the polarizing film to be integrated with the polarizing plate and from the viewpoint of durability of the polarizing film.

Specifically, in the cellulose acylate film having a small optical anisotropy (Re, Rth) used in the present invention, the front retardation Re and the thickness direction retardation Rth of the cellulose acylate film (support) are expressed by the formulas. [1] is satisfied, and the wavelength dispersibility satisfies the formula [2].
Formula [1] is preferably 0 ≦ Re (630) ≦ 5 and | Rth | ≦ 20 nm, more preferably 0 ≦ Re (630) ≦ 2 and | Rth | ≦ 15 nm.
Formula [2] is preferably | Re (400) −Re (700) | ≦ 5 and | Rth (400) −Rth (700) | ≦ 25, more preferably | Re (400) −Re. (700) | ≦ 3 and | Rth (400) −Rth (700) | ≦ 15.

  The support used in the present invention can be produced, for example, by the following method.

[Cellulose acylate raw material cotton]
Cellulose acylate raw material cellulose used in the present invention includes cotton linter and wood pulp (hardwood pulp, softwood pulp), etc., and any cellulose acylate obtained from any raw material cellulose can be used. May be. Detailed descriptions of these raw material celluloses can be found in, for example, Plastic Materials Course (17) Fibrous Resin (Maruzawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Open Technical Report 2001-1745 (page 7). To page 8), and any method can be preferably employed for the cellulose acylate film used in the present invention.

[Substitution degree of cellulose acylate]
Next, the cellulose acylate of the present invention produced from the above-mentioned cellulose will be described. The cellulose acylate preferably used in the present invention is one in which the hydroxyl group of cellulose is acylated, and the substituent can be, for example, an acyl group having an acetyl group having 2 to 22 carbon atoms. In the cellulose acylate used in the present invention, the degree of substitution of cellulose with a hydroxyl group is not particularly limited, but the degree of binding of acetic acid and / or a fatty acid having 3 to 22 carbon atoms substituted with a hydroxyl group of cellulose is measured and calculated. The degree of substitution can be obtained. As a measuring method, it can carry out according to ASTM D-817-91.

  As described above, in the cellulose acylate of the present invention, the degree of substitution of cellulose with a hydroxyl group is not particularly limited, but the acyl substitution degree of cellulose with a hydroxyl group is preferably 2.85 to 3.00. Furthermore, the substitution degree is preferably 2.87 to 3.00, and more preferably 2.90 to 3.00.

Among the acetic acid and / or the fatty acid having 3 to 22 carbon atoms substituted for the hydroxyl group of cellulose, the acyl group having 2 to 22 carbon atoms is not particularly limited, and may be an aliphatic group or an allyl group. It may be a mixture of more than one type. Examples of such an aliphatic group include an alkylcarbonyl ester group, an alkenylcarbonyl ester group, an aromatic carbonyl ester group, and an aromatic alkylcarbonyl ester group of cellulose. These groups may be further substituted with a substituent.
Specifically, examples of the acyl group 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, and octadecanoyl group. Noyl group, isobutanoyl group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group are preferred, acetyl group, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, tert- A butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group are more preferable, and an acetyl group, a propionyl group, and a butanoyl group are more preferable.

  In particular, among the acyl substituents substituted on the above-mentioned cellulose hydroxyl groups, when the acetyl group / propionyl group / butanoyl group are substantially composed of at least two kinds, the total substitution degree is 2.50 to 3.00. In this case, the optical anisotropy of the cellulose acylate film can be more effectively reduced. The acyl substitution degree is preferably 2.60 to 3.00, and more preferably 2.65 to 3.00.

[Structural characteristics of compounds that reduce the optical anisotropy of cellulose acylate films]
The cellulose acylate film used in the present invention may contain a compound that reduces optical anisotropy. Optical anisotropy was sufficiently reduced by using a compound that suppresses the orientation of cellulose acylate in the film in the plane and in the film thickness direction so that Re was zero and Rth was close to zero. For this purpose, it is advantageous that the compound that lowers the optical anisotropy is sufficiently compatible with cellulose acylate, and the compound itself does not have a rod-like structure or a planar structure. Specifically, when a plurality of planar functional groups such as aromatic groups are provided, a structure having these functional groups in a non-planar rather than the same plane is advantageous.

(Log P value)
In producing the cellulose acylate film of the present invention, octanol is one of the compounds that reduce the optical anisotropy by inhibiting the cellulose acylate in the film from being oriented in the plane and in the film thickness direction as described above. -The compound whose water partition coefficient (logP value) is 0-7 is preferable. A compound having a log P value of more than 7 is poor in compatibility with cellulose acylate, and tends to cause film turbidity or powder blowing. In addition, since a compound having a log P value smaller than 0 has high hydrophilicity, the water resistance of the cellulose acylate film may be deteriorated. A more preferable range for the logP value is 1 to 6, and a particularly preferable range is 1.5 to 5.
The octanol-water partition coefficient (log P value) can be measured by a flask immersion method described in JIS Japanese Industrial Standard Z7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement. As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987).), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163 (1989).) The Broto's fragmentation method (Eur. J. Med. Chem.-Chim. Theor., 19, 71 (1984)) is preferably used, but the Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27 , 21 (1987). When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the scope of the present invention by the Crippen's fragmentation method.

[Physical properties of compounds that reduce optical anisotropy]
The compound that reduces optical anisotropy may or may not contain an aromatic group. In addition, the compound that decreases the optical anisotropy preferably has a molecular weight of 150 to 3000, more preferably 170 to 2000, and even more preferably 200 to 1000. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.
The compound that reduces optical anisotropy is preferably liquid at 25 ° C. or a solid having a melting point of 25 to 250 ° C., more preferably liquid at 25 ° C. or a melting point of 25 to 200 ° C. It is a solid. Moreover, it is preferable that the compound which reduces optical anisotropy is a compound which does not volatilize in the process of dope casting at the time of preparation of a cellulose acylate film and drying.
The addition amount of the compound that decreases the optical anisotropy is preferably 0.01 to 30% by mass of the cellulose acylate, more preferably 1 to 25% by mass, and 5 to 20% by mass. Is more preferable.
Only one type of compound that reduces optical anisotropy may be used, or two or more types of compounds may be mixed and used in an arbitrary ratio.
The timing for adding the compound for reducing the optical anisotropy may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  The compound that reduces the optical anisotropy is such that the average content of the compound in the portion from the surface on at least one side to 10% of the total film thickness is the average content of the compound in the central portion of the cellulose acylate film. It is preferable that it is 80 to 99% of. The abundance of the compound of the present invention can be determined, for example, by measuring the amount of the compound at the surface and the central part by a method using an infrared absorption spectrum described in JP-A-8-57879.

  Specific examples of the compound for reducing the optical anisotropy of the cellulose acylate film preferably used in the present invention are represented by any of the following general formulas (13), (18), and (19). Although a compound is mentioned, this invention is not limited to these compounds.

［一般式（１３）において、Ｒ¹はアルキル基又はアリール基を表し、Ｒ²及びＲ³は、それぞれ独立に、水素原子、アルキル基又はアリール基を表す。ただしＲ¹、Ｒ²及びＲ³の炭素原子数の総和は１０以上である。］

[In General Formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. However, the total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more. ]

［一般式（１８）において、Ｒ¹はアルキル基又はアリール基を表し、Ｒ²及びＲ³はそれぞれ独立に水素原子、アルキル基又はアリール基を表す。］

[In General Formula (18), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. ]

［一般式（１９）において、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ独立にアルキル基又はアリール基を表す。］

[In General Formula (19), R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group or an aryl group. ]

The compound of the general formula (13) will be described.
In the general formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Moreover, it is particularly preferable that the total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more. R ¹ , R ² and R ³ may be substituted, and the substituent is preferably a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, or a sulfonamide group, an alkyl group, an aryl group, an alkoxy group, A sulfone group and a sulfonamide group are more preferable. Further, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and more preferably 6 to 20 (For example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, tert-amyl group, hexyl group, cyclohexyl group, heptyl group, octyl group) Group, bicyclooctyl group, nonyl group, adamantyl group, decyl group, tert-octyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, didecyl group) . The aryl group preferably has 6 to 30 carbon atoms, and more preferably 6 to 24 carbon atoms (for example, phenyl group, biphenyl group, terphenyl group, naphthyl group, binaphthyl group, triphenylphenyl group).
Preferred examples of the compound represented by the general formula (13) are shown below, but the present invention is not limited to these specific examples.

In the formula, Pr ⁱ represents an isopropyl group.

  Although the preferable example of a compound represented by General formula (18) or General formula (19) below is shown below, this invention is not limited to these specific examples. In the compound represented by the general formula (18) or the general formula (19), specific examples of the alkyl group and the aryl group are the same as those in the general formula (13).

  Preferable examples of other compounds that reduce optical anisotropy include compounds represented by the following general formula (1).

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted aliphatic acyl group, or a substituted or unsubstituted aromatic acyl group. It is more preferably a hydrogen atom or an aliphatic acyl group. The aliphatic acyl group may be linear, branched or cyclic. The number of carbon atoms in the aliphatic acyl group is preferably 1 to 12, more preferably 1 to 8, and most preferably 1 to 4. The aromatic acyl group may be an aromatic hydrocarbon acyl group or an aromatic heterocyclic acyl group, and more preferably an aromatic hydrocarbon acyl group. As the aromatic hydrocarbon acyl group, those having 6 to 24 carbon atoms are preferable, and those having 6 to 12 carbon atoms are more preferable. Examples of the substituent that the aliphatic acyl group and the aromatic acyl group may have include a substituent T described later.

R ² , R ³ and R ⁴ each represent a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group, and an aliphatic group is more preferred. The aliphatic group may be linear, branched or cyclic, more preferably branched or cyclic, and particularly preferably cyclic. The aliphatic group has preferably 5 to 24 carbon atoms, more preferably 5 to 15 carbon atoms, and most preferably 5 to 12 carbon atoms. The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. As the aromatic hydrocarbon group, those having 6 to 24 carbon atoms are preferable, and those having 6 to 12 carbon atoms are more preferable. Examples of the substituent that the aliphatic group and the aromatic group may have include a substituent T described later.

  The above-described substituted or unsubstituted aliphatic group will be further described below. The aliphatic group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, preferably 5 to 24, and preferably 5 to 15 Is more preferable, and 5 to 12 is most preferable. Specific examples of the aliphatic group include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, tert-amyl group. , N-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, bicyclooctyl group, adamantyl group, n-decyl group, tert-octyl group, dodecyl group, hexadecyl group, octadecyl group, didecyl group .

  The above-described substituted or unsubstituted aromatic group will be further described below. The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. As the aromatic hydrocarbon group, those having 6 to 24 carbon atoms are preferable, and those having 6 to 12 carbon atoms are more preferable. Specific examples of the ring of the aromatic hydrocarbon group include benzene, naphthalene, anthracene, biphenyl, terphenyl and the like. As the aromatic hydrocarbon group, benzene, naphthalene, and biphenyl are particularly preferable. As the aromatic heterocyclic group, those containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom are preferable. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, Examples include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. As the aromatic heterocyclic group, pyridine, triazine, and quinoline are particularly preferable.

Moreover, the above-mentioned substituent T is demonstrated below.
Substituent T:
An alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, an n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12, more preferably 2 to 8). For example, a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 2 carbon atoms). 8 such as propargyl group and 3-pentynyl group), aryl group (preferably having 6 to 30 carbon atoms, more preferred) 6 to 20, particularly preferably 6 to 12, and examples thereof include a phenyl group, a biphenyl group, and a naphthyl group.), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10, Particularly preferably 0 to 6, for example, amino group, methylamino group, dimethylamino group, diethylamino group, dibenzylamino group, etc.), alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12, particularly preferably 1 to 8, for example, methoxy group, ethoxy group, butoxy group, etc.), aryloxy group (preferably 6-20 carbon atoms, more preferably 6-16, particularly Preferably they are 6-12, for example, a phenyloxy group, 2-naphthyloxy group etc. are mentioned), an acyl group (preferably carbon atom number). To 20, more preferably 1 to 16, particularly preferably 1 to 12, and examples thereof include an acetyl group, a benzoyl group, a formyl group, and a pivaloyl group), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms). , More preferably 2 to 16, particularly preferably 2 to 12, and examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group.), An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably 7). -16, particularly preferably 7-10, for example, phenyloxycarbonyl group, etc.), acyloxy groups (preferably 2-20 carbon atoms, more preferably 2-16, particularly preferably 2-10). For example, acetoxy group, benzoyloxy group, etc.), acylamino group (preferably The number of carbon atoms is 2 to 20, more preferably 2 to 16, particularly preferably 2 to 10, and examples thereof include an acetylamino group and a benzoylamino group. ), An alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms such as a methoxycarbonylamino group), an aryloxycarbonylamino group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 and particularly preferably 7 to 12, and examples thereof include a phenyloxycarbonylamino group, and a sulfonylamino group (preferably 1 to 20 carbon atoms). More preferably, it is 1-16, Most preferably, it is 1-12, for example, a methanesulfonylamino group, a benzenesulfonylamino group, etc.), a sulfamoyl group (preferably C0-20, more preferably 0). To 16, particularly preferably 0 to 12, such as sulfamoyl group, methyl Rufamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group, etc.), carbamoyl group (preferably 1-20 carbon atoms, more preferably 1-16, particularly preferably 1-12, for example, Carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group, etc.), alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, Methylthio group, ethylthio group, etc.), arylthio group (preferably 6-20 carbon atoms, more preferably 6-16, particularly preferably 6-12, such as phenylthio group). A sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, Is preferably 1 to 12, for example, mesyl group, tosyl group, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, For example, a methanesulfinyl group, a benzenesulfinyl group, etc.), a ureido group (preferably 1-20 carbon atoms, more preferably 1-16, particularly preferably 1-12, for example, a ureido group, a methylureido group). , Phenylureido groups, etc.), phosphoric acid amide groups (preferably having 1-20 carbon atoms, more preferably 1-16, particularly preferably 1-12, such as diethylphosphoric acid amide, phenylphosphoric acid Amide etc.), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom) , Iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms). A hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom, specifically an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group, a morpholino group, a benzoxazolyl group, a benzimidazolyl group, Examples thereof include a benzthiazolyl group. ) And a silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms such as a trimethylsilyl group and a triphenylsilyl group).
These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Preferred examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited to these specific examples.

[Wavelength dispersion adjusting agent]
A compound (hereinafter also referred to as “wavelength dispersion adjusting agent”) that reduces wavelength dispersion may be added to the cellulose acylate film. In order to improve the Rth wavelength dispersion of the cellulose acylate film used in the present invention, the Rth wavelength dispersion ΔRth = | Rth (400) −Rth (700) | represented by the following formula (iv) is decreased. It is preferable to contain at least one compound within a range satisfying the following formulas (v) and (vi).
(Iv) ΔRth = | Rth (400) −Rth (700) |
(V) (ΔRth (B) −ΔRth (0)) / B ≦ −2.0
(Vi) 0.01 ≦ B ≦ 30
The above formulas (v) and (vi) are
(V) (ΔRth (B) −ΔRth (0)) / B ≦ −3.0
(Vi) 0.05 ≦ B ≦ 25
(V) (ΔRth (B) −ΔRth (0)) / B ≦ −4.0
(Vi) 0.1 ≦ B ≦ 20
More preferably.
The above-mentioned wavelength dispersion adjusting agent usually has absorption in the ultraviolet region of 200 to 400 nm, for example, by using 0.01 to 30% by mass with respect to the cellulose acylate solid content, Re of the cellulose acylate film, Rth wavelength dispersion can be adjusted.

  In general, the Re and Rth values of the cellulose acylate film used in the present invention tend to have a wavelength dispersion characteristic that is larger on the long wavelength side than on the short wavelength side. Therefore, it is usually required to smooth the chromatic dispersion by increasing Re and Rth on the relatively small short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance on the long wavelength side is larger than that on the short wavelength side. Therefore, when a compound having absorption in the ultraviolet region of 200 to 400 nm is isotropically present inside the cellulose acylate film, the birefringence of the compound itself, and thus the wavelength dispersion of Re and Rth, is similar to the wavelength dispersion of absorbance. The short wavelength side tends to increase.

  The wavelength dispersion of Re and Rth of the cellulose acylate film is adjusted by using a compound that absorbs in the ultraviolet region of 200 to 400 nm and the wavelength dispersion of Re and Rth of the compound itself is assumed to be large on the short wavelength side. can do. For this purpose, the compound for adjusting the wavelength dispersion is required to be sufficiently homogeneously compatible with the cellulose acylate. The absorption band range in the ultraviolet region of such a compound is preferably 200 to 400 nm, more preferably 220 to 395 nm, and even more preferably 240 to 390 nm.

  In recent years, liquid crystal display devices such as televisions, notebook personal computers, and mobile portable terminals have been required to have excellent transmittance of optical members used in liquid crystal display devices in order to increase luminance with less power. In that respect, a compound having absorption in the ultraviolet region of 200 to 400 nm and reducing | Re (400) -Re (700) | and | Rth (400) -Rth (700) | When it is added, it is required that the spectral transmittance is excellent. In the cellulose acylate film of the present invention, the spectral transmittance at a wavelength of 380 nm is preferably 45% to 95%, and the spectral transmittance at a wavelength of 350 nm is preferably 10% or less.

  As described above, the wavelength dispersion adjusting agent preferably used in the present invention preferably has a molecular weight of 250 to 1000 from the viewpoint of volatility. More preferably, it is 260-800, More preferably, it is 270-800, Most preferably, it is 300-800. The wavelength dispersion adjusting agent may be any of a monomer and an oligomer or a polymer in which the monomer is linked.

  It is preferable that the wavelength dispersion adjusting agent that can be used in the present invention is not volatilized in the process of dope casting and drying when producing a cellulose acylate film.

(Addition amount of wavelength dispersion adjusting agent)
The addition amount of the wavelength dispersion adjusting agent that can be used in the present invention is preferably 0.01 to 30% by mass of cellulose acylate, more preferably 0.1 to 20% by mass, and 0.2 More preferably, it is 10 mass%.

(Method of adding wavelength dispersion adjusting agent)
The wavelength dispersion adjusting agent that can be used in the present invention may be used alone or in a mixture of two or more at any ratio.
Further, the timing of adding the wavelength dispersion adjusting agent is preferably performed during any of the dope preparation steps for forming the cellulose acylate film of the present invention, and may be performed at the end of the dope preparation step. .

  Specific examples of the wavelength dispersion adjusting agent preferably used in the present invention include benzotriazole compounds, benzophenone compounds, compounds containing a cyano group, oxybenzophenone compounds, salicylic acid ester compounds, nickel complex compounds, and the like. The present invention is not limited to these compounds.

  As the benzotriazole-based compound, those represented by the general formula (101) are preferably used.

Formula (101) Q ¹ -Q ² -OH
(In the formula, Q ¹ represents a nitrogen-containing aromatic heterocycle, and Q ² represents an aromatic ring.)

Q ¹ represents a nitrogen-containing aromatic heterocycle, preferably a 5-membered to 7-membered nitrogen-containing aromatic heterocycle, more preferably a 5-membered or 6-membered nitrogen-containing aromatic heterocycle. For example, imidazole ring, pyrazole ring, triazole ring, tetrazole ring, thiazole ring, oxazole ring, selenazole ring, benzotriazole ring, benzothiazole ring, benzoxazole ring, benzoselenazole ring, thiadiazole ring, oxadiazole ring , Naphthothiazole ring, naphthoxazole ring, azabenzimidazole ring, purine ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, triazaindene ring, tetrazaindene ring, and the like, more preferably A 5-membered nitrogen-containing aromatic heterocycle, specifically an imidazole ring, Razoru ring, triazole ring, tetrazole ring, thiazole ring, oxazole ring, benzotriazole ring, benzothiazole ring, benzoxazole ring, thiadiazole ring, oxadiazole ring, and particularly preferably a benzotriazole ring.
The nitrogen-containing aromatic heterocycle represented by Q ¹ may further have a substituent, and the substituent T described later can be applied as the substituent. In addition, when there are a plurality of substituents, each may be condensed to form a ring.

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring is preferably a monocyclic or bicyclic aromatic hydrocarbon ring (benzene ring, naphthalene ring, etc.) having 6 to 30 carbon atoms, more preferably aromatic having 6 to 20 carbon atoms. It is a hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms, and particularly preferably a benzene ring.
As the aromatic heterocycle, an aromatic heterocycle containing a nitrogen atom or a sulfur atom is preferable. Specific examples of the hetero ring include thiophene ring, imidazole ring, pyrazole ring, pyridine ring, pyrazine ring, pyridazine ring, triazole ring, triazine ring, indole ring, indazole ring, purine ring, thiazoline ring, thiazole ring, thiadiazole ring, Oxazoline ring, oxazole ring, oxadiazole ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine ring, phenanthroline ring, phenazine ring, tetrazole ring, benzimidazole ring Benzoxazole ring, benzthiazole ring, benzotriazole ring, and tetrazaindene ring. Specific examples of the aromatic heterocycle include a pyridine ring, a triazine ring, and a quinoline ring.
The aromatic ring represented by Q ² is preferably an aromatic hydrocarbon ring, more preferably a naphthalene ring or a benzene ring, and still more preferably a benzene ring. Q ² may further have a substituent, and the substituent T described later is preferable.
Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, Isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms) More preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as vinyl, allyl group, 2-butenyl group and 3-pentenyl group), alkynyl group (preferably It has 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as a propargyl group, Tinyl group, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl group, p-methyl) A phenyl group, a naphthyl group, etc.), an amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as an amino group, A methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, etc.), an alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably the number of carbon atoms). 1 to 8, for example, methoxy group, ethoxy group, butoxy group, etc.), aryloxy group (preferably having 6 to 20 carbon atoms, More preferably, it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyloxy group and a 2-naphthyloxy group), an acyl group (preferably 1 to 20 carbon atoms). More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl groups, and alkoxycarbonyl groups (preferably carbon atoms). 2 to 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl group and ethoxycarbonyl group), aryloxycarbonyl group (preferably carbon 7 to 20 atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, And phenyloxycarbonyl group. ), An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include an acetoxy group and a benzoyloxy group). An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include an acetylamino group and a benzoylamino group), alkoxy. A carbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), aryloxycarbonyl An amino group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms such as phenyloxycarbonylamino group), sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon atoms) 1 to 12, for example, methanesulfonylamino group, benzenesulfonylamino group, etc.), sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably having 0 to 16 carbon atoms, particularly preferably carbon The number of atoms is 0 to 12, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group.), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Yl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group, etc.), alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 carbon atom). For example, a methylthio group, an ethylthio group, etc.), an arylthio group (preferably having 6 to 20 carbon atoms, more preferably having 6 to 16 carbon atoms, and particularly preferably having 6 to 12 carbon atoms). Yes, for example, a phenylthio group, etc.), a sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a mesyl group, Tosyl groups, etc.), sulfinyl groups (preferably having 1 to 20 carbon atoms, more preferably carbon atoms). The number is from 1 to 16, particularly preferably from 1 to 12, and examples thereof include a methanesulfinyl group and a benzenesulfinyl group. ), A ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include a ureido group, a methylureido group, and a phenylureido group. Phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide group, phenylphosphoric acid Amide group, etc.), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group , Hydrazino group, imino group, heterocyclic group (preferably having 1-30 carbon atoms, more preferably 1-12, As, for example, nitrogen atom, oxygen atom, sulfur atom, specifically, for example, imidazolyl group, pyridyl group, quinolyl group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, etc. ), A silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, such as a trimethylsilyl group or a triphenylsilyl group. Etc.). These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Preferred as the general formula (101) is a compound represented by the following general formula (101-A).

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、及びＲ⁸はそれぞれ独立に水素原子又は置換基を表す。）

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represents a hydrogen atom or a substituent.)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom or a substituent, and the above-described substituent T can be applied as the substituent. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.
R ¹ and R ³ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom, an alkyl group, An aryl group, an alkoxy group, an aryloxy group and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably an alkyl group having 1 to 12 carbon atoms (preferably the number of carbon atoms). 4-12).

R ² and R ⁴ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom or an alkyl group. , An aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom and a methyl group, most preferably a hydrogen atom. It is.

R ⁵ and R ⁸ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom, an alkyl group, An aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom and a methyl group, and most preferably a hydrogen atom.

R ⁶ and R ⁷ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom, an alkyl group, An aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and a halogen atom, and particularly preferably a hydrogen atom and a chlorine atom.

  More preferable as the general formula (101) is a compound represented by the following general formula (101-B).

（式中、Ｒ¹、Ｒ³、Ｒ⁶及びＲ⁷は一般式（１０１−Ａ）におけるそれらと同義であり、また好ましい範囲も同様である。）

(In formula, R < ¹ >, R < ³ >, R < ⁶ > and R < ⁷ > are synonymous with those in General Formula (101-A), and their preferred ranges are also the same.)

  Specific examples of the compound represented by formula (101) are listed below, but the present invention is not limited to the following specific examples.

  As described above, among the benzotriazole compounds exemplified above, it was confirmed that when a cellulose acylate film containing no molecular weight of 320 or less was used, it was advantageous in terms of retention of the obtained retardation film. .

  In addition, as the benzophenone compound which is one of the wavelength dispersion adjusting agents that can be used in the present invention, those represented by the general formula (102) are preferably used.

（式中、Ｑ¹及びＱ²はそれぞれ独立に芳香族環を表す。ＸはＮＲ（Ｒは水素原子又は置換基を表す。）、酸素原子又は硫黄原子を表す。）

(In the formula, Q ¹ and Q ² each independently represent an aromatic ring. X represents NR (R represents a hydrogen atom or a substituent), an oxygen atom or a sulfur atom.)

The aromatic ring represented by Q ¹ and Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring represented by Q ¹ and Q ² is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (eg, benzene ring, naphthalene ring, etc.). More preferably an aromatic hydrocarbon ring having 6 to 20 carbon atoms, and further preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms. More preferred is a benzene ring.
The aromatic heterocycle represented by Q ¹ and Q ² is preferably an aromatic heterocycle containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring include, for example, furan ring, pyrrole ring, thiophene ring, imidazole ring, pyrazole ring, pyridine ring, pyrazine ring, pyridazine ring, triazole ring, triazine ring, indole ring, indazole ring, purine ring, thiazoline. Ring, thiazole ring, thiadiazole ring, oxazoline ring, oxazole ring, oxadiazole ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine ring, phenanthroline ring, phenazine Ring, tetrazole ring, benzimidazole ring, benzoxazole ring, benzthiazole ring, benzotriazole ring, tetrazaindene ring and the like. The aromatic hetero ring is preferably a pyridine ring, a triazine ring or a quinoline ring.
The aromatic ring represented by Q ¹ and Q ² is preferably an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms, and still more preferably a benzene ring.

Q ¹ and Q ² may further have a substituent, and the above-described substituent T is preferable, but the substituent does not contain a carboxylic acid, a sulfonic acid, or a quaternary ammonium salt. Further, if possible, substituents may be linked to form a ring structure.

  X represents NR (R represents a hydrogen atom or a substituent. As the substituent, the above-described substituent T can be applied), an oxygen atom or a sulfur atom, and NR (R is preferably an acyl group or a sulfonyl group). These substituents may be further substituted), or an oxygen atom is preferred, and an oxygen atom is more preferred.

  As the general formula (102), a compound represented by the following general formula (102-A) is preferable.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸及びＲ⁹はそれぞれ独立に水素原子又は置換基を表す。）

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or a substituent.)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ each independently represent a hydrogen atom or a substituent, and the above-mentioned substituent T is applied as the substituent. it can. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ and R ⁹ are preferably a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, amino group, alkoxy group, aryloxy group, hydroxy group A halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, or a halogen atom, still more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, particularly preferably. Is a hydrogen atom or a methyl group, most preferably a hydrogen atom.

R ² is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom or a carbon atom number of 1 to 20 An alkyl group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group, more preferably an alkoxy having 1 to 20 carbon atoms. And particularly preferably an alkoxy group having 1 to 12 carbon atoms.

R ⁷ is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom or a carbon atom number of 1 to 20 An alkyl group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group, more preferably a hydrogen atom and 1 to 1 carbon atoms. 20 alkyl groups (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably methyl groups), and particularly preferably a methyl group and a hydrogen atom.

  More preferable as the general formula (102) is a compound represented by the following general formula (102-B).

（式中、Ｒ¹⁰は水素原子、アルキル基、アルケニル基、アルキニル基、アリール基を表す。）

(In the formula, R ¹⁰ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an aryl group.)

R ¹⁰ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the substituent T described above is preferred as the substituent that these groups have.
R ¹⁰ is preferably an alkyl group, more preferably an alkyl group having 5 to 20 carbon atoms, and still more preferably an alkyl group having 5 to 12 carbon atoms (n-hexyl group, 2-ethylhexyl group, n- Octyl group, n-decyl group, n-dodecyl group, benzyl group, etc.), particularly preferably an alkyl group having 6 to 12 carbon atoms (2-ethylhexyl group, n-octyl group, n -Decyl group, n-dodecyl group, benzyl group).

The compound represented by the general formula (102) can be synthesized by a known method described in JP-A-11-12219.
Specific examples of the compound represented by the general formula (102) are given below, but the present invention is not limited to the following specific examples.

  Moreover, as a compound containing a cyano group, which is one of the wavelength dispersion adjusting agents that can be used in the present invention, those represented by the general formula (103) are preferably used.

（式中、Ｑ¹及びＱ²はそれぞれ独立に芳香族環を表す。Ｘ¹及びＸ²は水素原子又は置換基を表し、少なくともどちらか１つはシアノ基、カルボニル基、スルホニル基、芳香族ヘテロ環を表す。）
Ｑ¹及びＱ²で表される芳香族環は芳香族炭化水素環でも芳香族ヘテロ環でもよい。また、これらは単環であってもよいし、さらに他の環と縮合環を形成してもよい。
芳香族炭化水素環として好ましくは炭素原子数６〜３０の単環又は二環の芳香族炭化水素環（例えば、ベンゼン環、ナフタレン環等）であり、より好ましくは炭素原子数６〜２０の芳香族炭化水素環、さらに好ましくは炭素原子数６〜１２の芳香族炭化水素環であり、特に好ましくはベンゼン環である。

(In the formula, Q ¹ and Q ² each independently represent an aromatic ring. X ¹ and X ² represent a hydrogen atom or a substituent, and at least one of them represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic group. Represents a heterocycle.)
The aromatic ring represented by Q ¹ and Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (eg, benzene ring, naphthalene ring, etc.), more preferably an aromatic having 6 to 20 carbon atoms. An aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms, and particularly preferably a benzene ring.

  The aromatic heterocycle is preferably an aromatic heterocycle containing a nitrogen atom or a sulfur atom. Specific examples of the hetero ring include, for example, thiophene ring, imidazole ring, pyrazole ring, pyridine ring, pyrazine ring, pyridazine ring, triazole ring, triazine ring, indole ring, indazole ring, purine ring, thiazoline ring, thiazole ring, thiadiazole. Ring, oxazoline ring, oxazole ring, oxadiazole ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine ring, phenanthroline ring, phenazine ring, tetrazole ring, benz Examples include an imidazole ring, a benzoxazole ring, a benzthiazole ring, a benzotriazole ring, and a tetrazaindene ring. The aromatic hetero ring is preferably a pyridine ring, a triazine ring or a quinoline ring.

The aromatic ring represented by Q ¹ and Q ² is preferably an aromatic hydrocarbon ring, and more preferably a benzene ring.
Q ¹ and Q ² may further have a substituent, and the above-described substituent T is preferable.

X ¹ and X ² each represent a hydrogen atom or a substituent, and at least one of them represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic heterocycle. The substituent T described above can be applied to the substituents represented by X ¹ and X ² . In addition, the substituent represented by X ¹ and X ² may be further substituted with another substituent, and X ¹ and X ² may each be condensed to form a ring structure.

X ¹ and X ² are preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, or an aromatic heterocycle, and more preferably a cyano group, a carbonyl group, a sulfonyl group, An aromatic heterocycle, more preferably a cyano group or a carbonyl group, and particularly preferably a cyano group or an alkoxycarbonyl group (—C (═O) OR (R is an alkyl group having 1 to 20 carbon atoms, a carbon atom) 6 to 12 aryl groups and combinations thereof.

  As the general formula (103), a compound represented by the following general formula (103-A) is preferable.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹及びＲ¹⁰はそれぞれ独立に水素原子又は置換基を表す。Ｘ¹及びＸ²は一般式（１０３）におけるそれらと同義であり、また好ましい範囲も同様である。）

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. X ¹ and X ² Are the same as those in formula (103), and the preferred range is also the same.)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent. Is applicable. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.

R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are preferably hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, amino group, alkoxy group, aryloxy group , A hydroxy group and a halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom, still more preferably a hydrogen atom and an alkyl group having 1 to 12 carbons. Preferred are a hydrogen atom and a methyl group, and most preferred is a hydrogen atom.

R ³ and R ⁸ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom or the number of carbon atoms. An alkyl group having 1 to 20 carbon atoms, an amino group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group, more preferably a hydrogen atom and a carbon atom. It is a C1-C12 alkyl group and a C1-C12 alkoxy group, Especially preferably, it is a hydrogen atom.

  More preferable as the general formula (103) is a compound represented by the following general formula (103-B).

（式中、Ｒ³及びＲ⁸は一般式（１０３−Ａ）におけるそれらと同義であり、また、好ましい範囲も同様である。Ｘ³は水素原子又は置換基を表す。）
Ｘ³は水素原子又は置換基を表し、置換基としては前述の置換基Ｔが適用でき、また、可能な場合はさらに他の置換基で置換されてもよい。Ｘ³として好ましくは水素原子、アルキル基、アリール基、シアノ基、ニトロ基、カルボニル基、スルホニル基、芳香族ヘテロ環であり、より好ましくは、シアノ基、カルボニル基、スルホニル基、芳香族ヘテロ環であり、さらに好ましくはシアノ基、カルボニル基であり、特に好ましくはシアノ基、アルコキシカルボニル基（−Ｃ（＝Ｏ）ＯＲ（Ｒは：炭素原子数１〜２０アルキル基、炭素原子数６〜１２のアリール基及びこれらを組み合せたもの）である。

(In the formula, R ³ and R ⁸ have the same meanings as those in formula (103-A), and preferred ranges are also the same. X ³ represents a hydrogen atom or a substituent.)
X ³ represents a hydrogen atom or a substituent. As the substituent, the above-described substituent T can be applied, and if possible, the substituent may be further substituted with another substituent. X ³ is preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group or an aromatic heterocyclic ring, more preferably a cyano group, a carbonyl group, a sulfonyl group or an aromatic heterocyclic ring. More preferably a cyano group or a carbonyl group, and particularly preferably a cyano group or an alkoxycarbonyl group (—C (═O) OR (R is an alkyl group having 1 to 20 carbon atoms, 6 to 12 carbon atoms). Aryl groups and combinations thereof).

  More preferred as the general formula (103) is a compound represented by the general formula (103-C).

（式中、Ｒ³及びＲ⁸は一般式（１０３−Ａ）におけるそれらと同義であり、また、好ましい範囲も同様である。Ｒ²¹は炭素原子数１〜２０のアルキル基を表す。）

(In formula, R < ³ > and R < ⁸ > are synonymous with those in General formula (103-A), and the preferable range is also the same. R < ²¹ > represents a C1-C20 alkyl group.)

R ²¹ is preferably an alkyl group having 2 to 12 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms, and still more preferably carbon when R ³ and R ⁸ are both hydrogen. An alkyl group having 6 to 12 atoms, particularly preferably an n-octyl group, a tert-octyl group, a 2-ethylhexyl group, an n-decyl group or an n-dodecyl group, most preferably 2-ethyl Hexyl group.

Preferably, when R ³ and R ⁸ are other than hydrogen as R ²¹ , the compound represented by the general formula (103-C) has a molecular weight of 300 or more and an alkyl having 20 or less carbon atoms. Groups are preferred.

  The compound represented by the general formula (103) can be synthesized by the method described in Journal of American Chemical Society 63, 3452 (1941).

  Specific examples of the compound represented by the general formula (103) are given below, but the present invention is not limited to the following specific examples.

[Optically anisotropic layer of first retardation film]
In the retardation film of the present invention, the retardation retardation Rth in the thickness direction and the retardation Rth in the thickness direction must satisfy the following formula [3], and the wavelength dispersion must satisfy the following formula [4]. It is.
[3] 0 ≦ Re (550) ≦ 10 and 100 ≦ Rth (550) ≦ 300
[4] 1.04 ≦ Rth (450) / Rth (550) ≦ 1.30

  As long as the optically anisotropic layer of the retardation film of the present invention has the optical properties, the material and form thereof are basically not particularly limited. For example, a polymer film (preferably a retardation film made of a birefringent polymer film), a film that is heated and stretched after forming a polymer compound on a support, and a low-molecular or polymer liquid crystalline compound is applied to the support or Any of retardation films having a retardation layer formed by transferring can be used. Moreover, each can also be laminated | stacked and used.

  For example, the low molecular liquid crystalline compound is preferably a homeotropically aligned polymerizable discotic liquid crystalline compound.

  In the present invention, the optically anisotropic layer containing a discotic liquid crystalline compound contains at least one of a discotic liquid crystalline compound and a compound represented by the general formula (I), (II), or (III) described later. It is preferable to do.

The discotic liquid crystalline compound can be aligned substantially horizontally with respect to the polymer film surface by using at least one of the compounds represented by formulas (I) to (III) described later. Here, “substantially horizontal” means that the average angle (average inclination angle) between the disc surface of the discotic liquid crystalline compound and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °. .
The discotic liquid crystalline compounds are described in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid crystal chemistry,
Chapter 5, 1 0 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)) can be widely used. For the polymerization of the discotic liquid crystalline compound, for example, a method described in JP-A-8-27284 can be employed.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound can be considered. A structure having a linking group between the discotic core and the polymerizable group is more preferable. When a structure having a linking group is employed, it becomes easier to maintain the alignment state in the polymerization reaction. The discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (VI).
Formula (VI)
D (-LP) _n
(In general formula (VI), D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12.)

  The discotic core (D), divalent linking group (L) and polymerizable group (P) in the formula (VI) are, for example, (D1) to (D15) described in JP-A-2001-4837. , (L1) to (L25) and (P1) to (P18) can be used. Specific examples include TE-8 shown below.

  In the case of a discotic liquid crystalline compound having a polymerizable group, it is substantially horizontally aligned as described above. As specific examples of the discotic liquid crystalline compound in this case, those described in International Publication WO01 / 88574A1 pamphlet, page 58, line 6 to page 65, line 8 can be preferably employed.

[Fluorine-containing surfactant]
The optically anisotropic layer of the retardation film of the present invention preferably contains at least one fluorine-containing surfactant in order to align the liquid crystalline compound or make the optical properties uniform in the plane. . The fluorine-containing surfactant may be a low molecular compound or a high molecular compound. For example, for low molecular compounds, compounds exemplified in JP-A-2005-128050 are preferred.

  The polymer compound preferably contains a fluoroaliphatic-containing polymer containing a repeating unit represented by the following general formula (1).

In the general formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) A group represented by LQ, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, and more preferably a hydrogen atom or a group having 1 to 1 carbon atoms. 4 is an alkyl group, particularly preferably a hydrogen atom or an alkyl group having 1 or 2 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like.
The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L is a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, —PO (OR ⁵ ) —, an alkylene group, an arylene group, or a combination thereof. Represents a valent linking group. Here, R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. R ⁵ represents an alkyl group, an aryl group, or an aralkyl group.
L preferably includes a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, an alkylene group, or an arylene group, and includes —CO—, —O—, — It is particularly preferred that it contains NR ⁴ —, an alkylene group, or an arylene group.
When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Specific examples of particularly preferable alkylene groups include a methylene group, an ethylene group, a trimethylene group, a tetrabutylene group, and a hexamethylene group.
When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene groups and naphthalene groups.
When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group.
The group listed as L may have a suitable substituent. Examples of such a substituent include those similar to the substituents exemplified above as the substituents for R ^{1 to} R ³ . Although the specific structure of L is illustrated below, this invention is not limited to these specific examples.

Q is not particularly limited as long as it is a polar group having hydrogen bonding properties. Preferably, hydroxyl group, carboxyl group, salt of carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, trimethylbenzylammonium, dimethylphenyl) ammonium etc.), pyridinium salt), an amide group of the carboxylic acid (N unsubstituted bodies, N- mono-lower alkyl-substituted, or N- di-lower alkyl-substituted bodies, e.g. _{-CONH 2, -CONHCH 3, -CON (} CH 3 ₂ ), a sulfo group, a salt of a sulfo group (examples of cations forming the salt are the same as those described for the carboxyl group), a sulfonamide group (N unsubstituted, N-mono lower alkyl substituted or N-di-lower alkyl substituents such as -S _{2 NH 2, -SO 2 NHCH 3} , such as _{-SO 2 N (CH 3) 2} ), phospho group, examples of the cation forming the salt of phospho group (salt are the same as those described in the above carboxyl group), a phosphonic amide (N unsubstituted, or N- mono-lower alkyl substituted compound, for example, _{-OP (= O) (NH 2} ) 2, -OP (= O) (NHCH 3) 2 , etc.), a ureido group (-NHCONH _2), Examples thereof include an amino group (—NH ₂ , —NHCH ₃ ) which is unsubstituted or monosubstituted at the N position (wherein the lower alkyl group represents a methyl group or an ethyl group). More preferred are a hydroxyl group, a carboxyl group, a sulfo group, and a phospho group, and particularly preferred is a hydroxyl group or a carboxyl group.

  The repeating unit contained in the polymer may be one kind alone, or two or more kinds of repeating units may be present simultaneously. A repeating unit having a carboxylic acid or a repeating unit having an acrylamide group is particularly preferred.

  Further, the fluoroaliphatic-containing polymer may have one or more repeating units derived from a fluoroaliphatic group-containing monomer. Preferably, it contains a fluoroaliphatic group-containing monomer described in general formula (I) or general formula (II) of JP-A-2006-126768. Specifically, it may contain one type of repeating unit derived from a monomer selected from the monomer group described in JP-A 2006-126768 [0033] to [0044], or two or more types. You may do it.

  Further, the fluoroaliphatic-containing polymer may contain a repeating unit other than the above. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. The fluoroaliphatic polymer may contain one type of repeating unit derived from a monomer selected from the monomer group described in [0026] to [0033] of JP-A-2004-46038, You may contain more than a seed.

  The fluoroaliphatic-containing polymer may contain a repeating unit derived from a monomer represented by the general formula [2] described in JP-A-2004-333852.

  The fluoroaliphatic-containing polymer may have a polymerizable group as a substituent in order to fix the alignment state of the liquid crystal compound.

  In the fluoroaliphatic-containing polymer used in the present invention, the polymerized units of the monomer having a fluoroaliphatic group is preferably 25 to 99% by mass based on the total polymerized units constituting the fluoropolymer. A more desirable ratio varies depending on the structure of the fluoroaliphatic group, and the polymerized units of the monomer represented by the general formula (I) in JP-A No. 2006-126768 are based on the total polymerized units constituting the fluoropolymer, It is preferably 99% by mass, more preferably 60-97% by mass, and even more preferably 70-95% by mass. The polymerization unit of the monomer represented by the general formula (II) in JP-A-2006-126768 is preferably 25 to 80% by mass based on the total polymerization units constituting the fluoropolymer, and 30 to 70% by mass. % Is more preferable, and it is more preferable that it is 35-65 mass%. Further, two or more kinds of fluoroaliphatic group-containing monomers may be contained in one polymer, and one or more monomers each represented by the general formula (I) and one represented by the general formula (II) are used. It may be included at the same time.

  A preferred mass average molecular weight of the fluoroaliphatic-containing polymer used in the present invention is 2,000 to 100,000, more preferably 3,000 to 80,000, and still more preferably 4,000 to 60,000. 000. Here, the mass average molecular weight and the molecular weight were converted into polystyrene by GTH analyzer using columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (both trade names manufactured by Tosoh Corp.) by detection of solvent THF and differential refractometer. Is the molecular weight.

  The said fluoroaliphatic content polymer used for this invention can be manufactured by a well-known and usual method. For example, it can be produced by adding a general-purpose radical polymerization initiator into an organic solvent containing a fluorine-based monomer, a monomer having a hydrogen bonding group, and the like, and polymerizing it. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition. More specifically, it is preferable to use the method described in [0035] to [0041] of JP-A-2004-46038.

[Fixation of alignment state of liquid crystalline compounds]
When the optically anisotropic layer of the retardation film of the present invention is formed from a liquid crystal compound, it is preferable to fix the aligned liquid crystal compound while maintaining the alignment state. The immobilization is preferably carried out by a polymerization reaction of a polymerizable group introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and a photopolymerization reaction is more preferable. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), 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 Combinations with phenyl ketone (described in US Pat. No. 3,549,367), acridine compounds and phenazine compounds (described in JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds ( (Described in US Pat. No. 4,221,970) Can be adopted.

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

  The optically anisotropic layer is preferably formed by applying an optically anisotropic layer coating liquid containing a liquid crystalline compound and the above polymerization initiator and other additives onto the alignment film. As the solvent used for the preparation of the optically anisotropic layer coating solution, an organic solvent is preferably used. Examples of the organic solvent include amide (for example, N, N-dimethylformamide), sulfoxide (for example, dimethyl sulfoxide), heterocyclic compound (for example, pyridine), hydrocarbon (for example, benzene, hexane), alkyl halide (for example, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane) can be employed. Of these, alkyl halides and ketones are preferred. Further, two or more organic solvents may be used in combination. For the application of the coating solution, known methods (for example, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method) can be widely adopted.

[Alignment film]
In order to align the liquid crystalline compound, it is preferable to use an alignment film. Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. The type of polymer used for the alignment film can be determined according to the alignment (particularly the average tilt angle) of the liquid crystal compound. For example, in order to align the liquid crystalline compound horizontally, a polymer (ordinary alignment polymer) that does not decrease the surface energy of the alignment film is used. Regarding specific types of polymers, matters described in known literatures on liquid crystal cells or optical compensation sheets can be widely adopted. In particular, when the liquid crystalline compound is aligned in a direction orthogonal to the rubbing treatment direction, for example, modified polyvinyl alcohol described in JP-A No. 2002-62427 and acrylic resin described in JP-A No. 2002-98836 are disclosed. An acid copolymer, a polyimide described in JP-A No. 2002-268068, and a polyamic acid can be preferably used. Any alignment film preferably has a polymerizable group for the purpose of improving the adhesion between the liquid crystalline compound and the support. The polymerizable group can be introduced by introducing a repeating unit having a polymerizable group in the side chain or as a substituent of a cyclic group. It is more preferable to use an alignment film that forms a chemical bond with the liquid crystal compound at the interface. As such an alignment film, for example, those described in JP-A-9-152509 can be employed.

  The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm. In addition, after aligning a liquid crystalline compound using an alignment film, the liquid crystalline compound is fixed in the alignment state to form an optically anisotropic layer, and only the optically anisotropic layer is formed as a polymer film (or a support). ) May be transferred onto.

  Another preferred example of the optically anisotropic layer is a liquid crystal monomer molecule (polymerizable liquid crystal) used for a twist-aligned polymerizable chiral nematic (cholesteric) liquid crystal layer having a reflection wavelength capable of three-dimensional crosslinking in the ultraviolet region. Molecule). For example, there are mixtures of liquid crystalline monomers and chiral compounds as disclosed in JP-A-7-258638 and JP-A-10-508882. As an example of such a polymerizable liquid crystal material, two or more types of compounds included in the following compound K and the following compounds A to J can be mixed and used. In the case of the liquid crystalline monomer represented by compound K, X is preferably an integer of 2 to 5.

  Moreover, as a chiral agent, a chiral agent as shown by the compound L-the compound N can be used, for example. In the case of the chiral agent represented by compound L or compound M, X is preferably an integer of 2 to 12, and in the case of the chiral agent represented by compound N, X is an integer of 2 to 5. Is desirable.

Further preferable examples of other optically anisotropic layers include various polymer materials whose refractive index increases in the in-plane direction with respect to the normal direction of the film surface after film formation, polymerizable low molecular compounds capable of giving a polymer, and the like. It is done. Specifically, materials disclosed in JP 2000-190385 A can be used. Examples thereof include various polymers such as polyamide, polyimide, polyamic acid, polyester or polyesteramide having at least one kind of aromatic ring, or polymerizable low molecular compounds capable of giving these polymers. These may be used alone or in combination.
Moreover, the film which extended | stretched the film after film-forming the said polymer film etc., and added the process which enlarges in-plane optical anisotropy can also be employ | adopted. For the stretching treatment, one or two or more of appropriate methods such as a biaxial stretching method such as a sequential method or a simultaneous method, a uniaxial stretching method such as a free end method or a fixed end method can be applied. From the viewpoint of effectively expressing Rth, the biaxial stretching method is preferable.

  As said polyamide, the polymer containing the polymer unit represented by following formula (1) is mentioned, for example.

In the formula, X and R ¹ are arbitrary residues, and at least one is a group containing an aromatic ring.

  X is preferably represented by any of the following. Here, Me is a methyl group.

R ¹ is preferably represented by any of the following.

但し、上記式中ｒは２〜１２の数を示し、ｓは１〜５００の数を示し、ｔは０〜５００の数を示す。

In the above formula, r represents a number of 2 to 12, s represents a number of 1 to 500, and t represents a number of 0 to 500.

（式中ｍは平均重合度である。またＹは、

Examples of the polyimide include a polymer represented by the following formula (6):

(Where m is the average degree of polymerization and Y is

等を表す。
前記ポリアミック酸としては、例えば下記式（１０）〜（１２）で示されるポリマーを挙げることができる。 R ² is a group such as

Etc.
Examples of the polyamic acid include polymers represented by the following formulas (10) to (12).

（式中ｎは２〜４００の数を示す。）
なお、前記ポリアミック酸を用いる場合、溶液塗布、乾燥した後、熱処理によりイミド化することが好ましい。

(In the formula, n represents a number of 2 to 400.)
In addition, when using the said polyamic acid, it is preferable to imidize by heat processing, after apply | coating a solution and drying.

[Second retardation film]
The liquid crystal display device of the present invention preferably has the first retardation film and the second retardation film. Here, the front retardation and the retardation in the thickness direction of the second retardation film satisfy the following formula [6], and / or the wavelength dispersion of the second retardation film satisfies the following formula [7]. It is preferable to satisfy.
[6] 70 ≦ Re (550) ≦ 180 and 30 ≦ Rth (550) ≦ 140
[7] 0.7 ≦ Re (450) / Re (550) ≦ 1.0
The second retardation film that can be used in the present invention may be optically uniaxial or biaxial. The second retardation film that can be used in the present invention is preferably a polymer, but is not particularly limited as long as various properties of the desired film can be obtained. The polymer to be used is not particularly limited as long as uniform biaxial orientation can be achieved. For example, norbornene polymer, polycarbonate polymer, polyarylate polymer, polyester polymer, polysulfone, etc. Aromatic polymers, triacetyl cellulose, and the like that can be formed by a solution casting method, an extrusion molding method, or the like. A biaxial optically anisotropic layer is a film produced by an appropriate method such as an extrusion molding method or a casting film forming method, such as a longitudinal stretching method using a roll, a transverse stretching method using a tenter, a biaxial stretching method, etc. Thus, it can be formed by stretching.

The Re value of the second retardation film that can be used in the present invention is preferably 80 to 170 nm, and more preferably 90 to 160 nm. Further, the value of Rth is preferably 40 to 120 nm, more preferably 50 to 100 nm.
The wavelength dispersibility represented by Re (450) / Re (550) is preferably 0.73 to 0.95, and more preferably 0.75 to 0.90.

  In the longitudinal stretching method using the roll, a heating method such as a method using a heating roll, a method of heating an atmosphere, or a method of using them together can be employed. Moreover, in the biaxial stretching method using a tenter, methods such as a simultaneous biaxial stretching method using an all tenter method and a sequential biaxial stretching method using a roll tenter method can be employed. Moreover, a thing with little orientation nonuniformity and phase difference nonuniformity is preferable. Although the thickness can be appropriately determined depending on the phase difference or the like, generally 1 to 300 μm is preferable, 10 to 200 μm is more preferable, and 20 to 150 μm is more preferable from the viewpoint of thinning.

  The norbornene-based polymer employed in the optically anisotropic layer is mainly composed of norbornene-based monomers such as norbornene and its derivatives, tetracyclododecene and its derivatives, dicyclopentadiene and its derivatives, methanotetrahydrofluorene and its derivatives. And a monomer polymer. For example, a ring-opening polymer of a norbornene monomer, a ring-opening copolymer of a norbornene monomer and another monomer capable of ring-opening copolymerization, an addition polymer of a norbornene monomer, and a norbornene monomer and a copolymer thereof Examples include addition copolymers with other possible monomers, and hydrogenated products thereof. Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a ring-opening polymer hydride of a norbornene monomer is most preferable. The molecular weight of the norbornene-based polymer, the monocyclic olefin polymer or the cyclic conjugated diene polymer is appropriately selected according to the purpose of use. For example, it is a polyisoprene or polystyrene-converted weight average molecular weight measured by gel permeation chromatography of a cyclohexane solution (or a toluene solution when the polymer resin does not dissolve), preferably 5,000 to 500,000. More preferably, it is the range of 8,000-200,000, More preferably, it is the range of 10,000-100,000. When the average molecular weight is such, the mechanical strength and molding processability of the film of the optically anisotropic layer obtained are highly balanced and suitable.

  Examples of the polycarbonate polymer used in the optically anisotropic layer include a mixture with polycarbonate and other polymers.

  Examples of the polyarylate polymer used in the optically anisotropic layer include polyoxybenzoate and mixtures with other polymers.

  Examples of the polyester polymer employed in the optically anisotropic layer include polyethylene terephthalate, polyethylene isophthalate, polyphenylene isophthalate, polybutylene terephthalate, polyethylene-2.6-naphthalate, and mixtures with other polymers.

  Examples of the aromatic polymer such as polysulfone employed in the optically anisotropic layer include polysulfone, polyethersulfone, polyallylsulfone, and the like and mixtures with other polymers.

  The glass transition temperature Tg of the polymer employed in the optically anisotropic layer of the present invention is appropriately determined according to the purpose of use. The glass transition temperature of the resin is preferably 70 ° C or higher, more preferably 80 ° C to 250 ° C, and still more preferably 90 ° C to 200 ° C. When a resin in this range is employed, heat resistance and molding processability are highly balanced, which is preferable.

  As the second retardation film of the present invention, as the most preferable examples, JP 2000-137116 A, JP 2002-14234 A, JP 2002-48919 A, International Publication WO 00/26705 pamphlet, A stretched polymer film or a composite stretched film in which the retardation has reverse wavelength dispersion characteristics as disclosed in, for example, Kaihei 2-120804 can be used. Typically, a polycarbonate film having a fluorene skeleton produced by stretching a film containing liquid crystal, a cellulose acetate film produced by stretching the film, an aromatic polyester polymer having a positive wavelength dispersion characteristic, and a reverse wavelength dispersion A film made of a mixture with a characteristic aromatic polyester polymer and stretched, or a polymer made of a copolymer containing monomer units that form a polymer with different wavelength dispersion characteristics. There are a film, a composite film in which two stretched films having different wavelength dispersion characteristics are laminated, and the like.

  As a method for molding the resin into a sheet or film, for example, either a heat-melt molding method or a solution casting method can be used. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, a stretch molding method, etc. Among these methods, mechanical strength, surface In order to obtain a film excellent in accuracy and the like, the extrusion molding method, the inflation molding method, and the press molding method are preferable, and the extrusion molding method is most preferable. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the heat-melt molding method, the cylinder temperature is preferably set in the range of preferably 100 to 400 ° C, more preferably 150 to 350 ° C. The thickness of the sheet or film is preferably 10 to 300 μm, more preferably 30 to 200 μm.

  The stretching of the sheet or film is preferably a temperature range of (Tg-30) ° C. to (Tg + 60) ° C., more preferably (Tg−60), where Tg is the glass transition temperature of the polymer employed in the optically anisotropic layer. It is carried out at a temperature of Tg-10) ° C. to (Tg + 50) ° C. in at least one direction, preferably at a draw ratio of 1.01 to 2 times. When the sheet is obtained by extrusion molding, the stretching direction is preferably the mechanical flow direction (extrusion direction) of the resin. The stretching method is preferably a free shrink uniaxial stretching method, a fixed width uniaxial stretching method, a biaxial stretching method, or the like.

Here, an example of a specific method of stretching will be given.
(1) The sheet is adjusted to a desired temperature by passing it through a roll (heated roll) heated to a constant temperature.
(2) Next, the temperature-adjusted sheet is stretched by passing through the first roll having a relatively low rotation speed and the second roll having a higher rotation speed. By controlling the speed ratio between the rotation speed of the first roll and the rotation speed of the second roll, the draw ratio can be adjusted in the range of 1 to 4 times. In addition, it is preferable to install an infrared heater etc. between a heating roll, a 1st roll, and a 2nd roll, and hold | maintain the temperature of a sheet | seat constant.
(3) The stretched film is cooled through a cooling roll.
(4) The cooled stretched film is collected with a winding roll. For the purpose of preventing blocking between films due to winding, a masking film having the same width as the stretched film may be stacked and wound together, or at least one end of the stretched film, preferably both ends, You may wind together, sticking thin tape etc. of weak adhesive strength.
In the step (1) of the above method, the sheet passing through the heating roll may be in a state where the temperature is higher than that of the heating roll, that is, a state immediately after being formed by an extruder or the like. Moreover, since it can be made into a high draw ratio, the thing of temperature lower than a heating roll and room temperature (for example, 25-30 degreeC) may be sufficient. Preferably, it is room temperature. Such a low-temperature sheet can be obtained by forming a sheet, cooling it once, and winding and collecting it on a roll. The stretching speed is preferably 5 to 1000 mm / second, more preferably 10 to 750 mm / second. When the stretching speed is in the above range, stretching control is facilitated, and further, surface accuracy and in-plane variation of retardation can be further reduced.

[Polarizing film]
Next, the polarizing film used in the liquid crystal display device of the present invention will be described in detail. The polarizing film employed in the present invention is not particularly limited, and known materials can be widely employed. For example, films made of hydrophilic polymers such as polyvinyl alcohol, partially formalized polyvinyl alcohol, partially saponified ethylene / vinyl acetate copolymer, dichroic dyes such as iodine and / or azo, anthraquinone and tetrazine A material obtained by adsorbing a dichroic material composed of the above material and subjecting it to stretching and orientation can be used. In the present invention, it is preferable to use the stretching method described in JP-A No. 2002-131548, and in particular, a width direction uniaxial stretching type tenter stretching machine in which the absorption axis of the polarizing film is substantially perpendicular to the longitudinal direction. It is preferable to use it.

The polarizing film is used as a polarizing plate whose both surfaces are protected by protective films. As will be described later, the retardation film of the present invention is preferably used as a protective film for a polarizing film.
When a protective film other than the retardation film of the present invention is used as the protective film, the type of the protective film is not particularly limited, and cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose propionate, polycarbonate, polyolefin, Polystyrene, polyester, etc. can be used. The protective film is usually supplied in a roll form, and it is preferable that the protective film is continuously bonded to the long polarizing film so that the longitudinal directions thereof coincide. Here, the orientation axis (slow axis) of the protective film may be any direction, but the orientation axis of the protective film is preferably parallel to the longitudinal direction from the operational convenience. Further, the angle between the slow axis (alignment axis) of the protective film and the absorption axis (stretching axis) of the polarizing film is not particularly limited, and can be appropriately set according to the purpose of the polarizing plate.

  When a protective film other than the retardation film of the present invention is used as the protective film, the Re value of the protective film is, for example, preferably 10 nm or less at 632.8 nm, and more preferably 5 nm or less. From the viewpoint of such a low retardation, polyolefins such as cellulose triacetate, ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used as the protective film. . Other examples include non-birefringent optical resin materials as described in JP-A-8-110402 or JP-A-11-293116. When cellulose acetate is used for the protective film, Re and Rth are preferably less than 10 nm, and more preferably 2 nm or less, for the purpose of reducing a change in retardation due to environmental temperature and humidity.

  In the present invention, for the purpose of reducing the thickness, one of the protective films of the polarizing film may also serve as the support for the optically anisotropic layer, or the optically anisotropic layer itself. The optically anisotropic layer and the polarizing film are preferably subjected to a fixing treatment from the viewpoint of preventing displacement of the optical axis and preventing entry of foreign matters such as dust. An appropriate method such as an adhesive method through a transparent adhesive layer can be applied to the fixed lamination. There is no particular limitation on the type of the adhesive and the like, and from the viewpoint of preventing changes in the optical properties of the constituent members, those that do not require a high-temperature process during curing or drying are preferable, and a long-time curing process is preferable. And those that do not require drying time. From such a viewpoint, a hydrophilic polymer adhesive or a pressure-sensitive adhesive layer is preferably used.

  For the formation of the pressure-sensitive adhesive layer, for example, a transparent pressure-sensitive adhesive using an appropriate polymer such as an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyether, or synthetic rubber can be used. Among these, acrylic pressure-sensitive adhesives are preferred from the viewpoints of optical transparency, adhesive properties, weather resistance, and the like. In addition, an adhesion layer can also be provided as needed on one side or both sides of a polarizing plate for the purpose of adhesion to an adherend such as a liquid crystal cell. In that case, when the pressure-sensitive adhesive layer is exposed on the surface, it is preferable to temporarily attach a separator or the like to prevent contamination of the pressure-sensitive adhesive layer surface until it is put to practical use.

  Appropriate functional layers such as a protective film for various purposes such as water resistance according to the above protective film, an antireflection layer and / or an antiglare treatment layer for the purpose of preventing surface reflection, etc. on one or both sides of the polarizing film You may use the polarizing plate which formed. The antireflection layer can be suitably formed, for example, as a light interference film such as a fluorine polymer coating layer or a multilayer metal vapor deposition film. The antiglare layer is also formed by an appropriate method that diffuses the surface reflected light, for example, by providing a fine uneven structure on the surface by an appropriate method such as a resin coating layer containing fine particles, embossing, sandblasting or etching. can do.

  Examples of the fine particles include inorganic materials such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.5 to 20 μm. One kind or two or more kinds of fine particles, such as crosslinked or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate and polyureta can be used. The above-mentioned adhesive layer or pressure-sensitive adhesive layer may contain such fine particles and exhibit light diffusibility.

[Optical performance of polarizing plate]
The polarizing plate of this invention contains a protective film, a polarizing film, a support body etc. as needed. The optical properties and durability (short-term and long-term storage stability) of the polarizing plate of the present invention should be equal to or better than those of a commercially available super high contrast product (for example, HLC2-5618 manufactured by Sanlitz Co., Ltd.). Is preferred. Specifically, the visible light transmittance is 42.5% or more, and the degree of polarization ({(Tp−Tc) / (Tp + Tc)} _1/2 ≧ 0.9995 (where Tp is parallel transmittance and Tc is orthogonal) The change rate of the light transmittance before and after leaving for 500 hours in a 60 ° C., 90% humidity RH atmosphere and 500 ° C. in a dry atmosphere for 500 hours is 3% based on the absolute value. In the following, it is further preferable that the change rate of the polarization degree is 1% or less, further 0.1% or less based on the absolute value.

  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 1]
<Production of liquid crystal cell>
(Preparation of vertical alignment liquid crystal cell)
1% by mass of octadecyldimethylammonium chloride (coupling agent) was added to a 3% by mass aqueous polyvinyl alcohol solution. This was spin-coated on a glass substrate with an ITO electrode, heat-treated at 160 ° C., and then rubbed to form a vertical alignment film. The rubbing treatment was performed so that the two glass substrates were in opposite directions. Two glass substrates were faced to each other so that the cell gap (d) was about 5.0 μm. A liquid crystal compound (Δn: 0.06) mainly composed of ester and ethane was injected into the cell gap to produce a vertically aligned liquid crystal cell. The product of Δn and d was 300 nm.

<Preparation of support 1>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution A.
Composition of cellulose acetate solution A ――――――――――――――――――――――――――――――――――――
Cellulose acetate with an acetyl substitution degree of 2.94 100.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass ――――――――――――― ――――――――――――――――――――――

(Preparation of matting agent solution)
20 parts by mass of silica particles having an average particle size of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) and 80 parts by mass of methanol were mixed well for 30 minutes to obtain a silica particle dispersion. This dispersion was put into a disperser together with the following composition, and further stirred for 30 minutes or more to dissolve each component to prepare a matting agent solution.
Matting agent solution composition ――――――――――――――――――――――――――――――――――
Silica particle dispersion with an average particle size of 16 nm 10.0 parts by weight Methylene chloride (first solvent) 76.3 parts by weight Methanol (second solvent) 3.4 parts by weight Cellulose acetate solution A 10.3 parts by weight ―――――――――――――――――――――――――――――

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare an additive solution.
Additive solution composition ――――――――――――――――――――――――――――――
The following retardation reducing agent 49.3 parts by mass The following wavelength dispersion adjusting agent 4.9 parts by mass Methylene chloride (first solvent) 58.4 parts by mass Methanol (second solvent) 8.7 parts by mass Cellulose acetate solution A 12 .8 parts by mass ――――――――――――――――――――――――――――――

(Production of cellulose acetate film)
94.6 parts by mass of the cellulose acetate solution A, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the additive solution were mixed after filtration, and cast using a band casting machine. In the above composition, the mass ratios of the retardation reducing agent and the wavelength dispersion adjusting agent to cellulose acetate were 12% and 1.2%, respectively. The film was peeled from the band with a residual solvent amount of 30% and dried at 140 ° C. for 40 minutes to produce a long cellulose acetate film having a thickness of 80 μm. The obtained film had an in-plane retardation (Re) of 1 nm and a thickness direction retardation (Rth) of 3 nm.
Moreover, | Re (400) −Re (700) | was 4 nm, and | Rth (400) −Rth (700) | was 12 nm.

<Preparation of Support 2>
In the same manner as the support 1, the cast film thickness was adjusted to produce a long cellulose acetate film having a thickness of 35 μm. The obtained film had an in-plane retardation (Re) of 0 nm and a thickness direction retardation (Rth) of 0 nm.
Moreover, | Re (400) −Re (700) | was 2 nm, and | Rth (400) −Rth (700) | was 6 nm.

<Preparation of support 3>
The support 3 was produced by the method described below.
(Production of polymer 1)
The following composition is put into a four-necked flask (installed with an inlet, a thermometer, a reflux condenser, a nitrogen inlet, and a stirrer), gradually heated to 80 ° C., and polymerized for 5 hours while stirring. After completion, the polymer solution was poured into a large amount of methanol to precipitate, further washed with methanol, purified and dried to obtain polymer 1 having a weight average molecular weight of 3,000 (measured by GPC).
Methyl acrylate 10 parts by mass 2-hydroxyethyl acrylate 1 part by mass Azobisisobutyronitrile (AIBN) 1 part by mass Toluene 30 parts by mass

(Film formation of support 3)
The following dope composition was put into a pressure sealed container and heated to 70 ° C. to bring the pressure in the container to 1 atm or more, and the cellulose ester was completely dissolved while stirring. The dope temperature was lowered to 35 ° C. and allowed to stand overnight, and this dope was added to Azumi Filter Paper No. After filtration using 244, the mixture was further left standing overnight to degas. Next, a filtration pressure of 1.0 using Finemet NM (absolute filtration accuracy 100 μm) and Finepore NF (absolute filtration accuracy 50 μm, 15 μm, 5 μm in order of absolute filtration accuracy) manufactured by Nippon Seisen Co., Ltd. It filtered by * 10 < ⁶ > Pa and used for film forming. The film thickness was 40 μm.
The obtained film had an in-plane retardation (Re) of 0.6 nm and a thickness direction retardation (Rth) of -2.9 nm.
Moreover, | Re (400) −Re (700) | was 3 nm, and | Rth (400) −Rth (700) | was 15 nm.

<Dope composition>
Cellulose triacetate (degree of substitution 2.83) 100 parts by mass Polymer 1 15 parts by mass The following UV agent (1) 0.8 parts by mass The following UV agent (2) 0.2 parts by mass Methylene chloride 475 parts by mass Ethanol 50 parts by mass Part

<Preparation of support 4>
A support 4 was produced in the same manner as the support 1 except that the retardation reducing agent of the support 1 was replaced with the compound A-1.
The obtained film had an in-plane retardation (Re) of 0 nm and a thickness direction retardation (Rth) of 2 nm.
Also, | Re (400) −Re (700) | was 3 nm, and | Rth (400) −Rth (700) | was 10 nm.

<Preparation of the first retardation film 1>
After the surface of the support 1 was saponified, an alignment film coating solution having the following composition was coated on the film with a wire bar coater at 20 ml / m ² . The film was formed by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, the formed film was rubbed in a direction parallel to the slow axis direction of the film to form an alignment film.
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 Compound B 0.2 parts by weight ―――――――――――――――――――― ―――――――――――――――

Next, an optically anisotropic layer coating solution having the following composition was applied with a wire bar so that the Rth in the thickness direction after curing was 200 nm.
―――――――――――――――――――――――――――――――――――
The following discotic liquid crystalline compound 1.8g
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.06 g
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02g
Fluorine-containing polymer (compound A below) 0.01g
Methyl ethyl ketone 3.9g
―――――――――――――――――――――――――――――――――――
This was affixed to a metal frame and heated in a thermostatic bath at 125 ° C. for 3 minutes to align the discotic liquid crystalline compound. Next, using a 120 W / cm high-pressure mercury lamp, UV irradiation was performed for 30 seconds to crosslink the discotic liquid crystalline compound. The temperature at the time of UV curing was set to 80 ° C. to obtain a retardation film. The thickness of the optically anisotropic layer was 2.8 μm. Then, it stood to cool to room temperature. Thus, the retardation film 1 was produced. The optical characteristics of the retardation film 1 are shown in Table 1.

<Production of first retardation films 2 to 5>
Next, the first retardation films 2 to 5 were produced in the same manner as the first retardation film 1 except that the coating amount of the optically anisotropic layer coating solution was changed. The thickness of the optically anisotropic layer of the obtained first retardation film was 3.5 μm, 2.1 μm, 0.7 μm, and 4.9 μm in order. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 6>
Next, a first retardation film 6 was produced in the same manner as the first retardation film 1 except that the support 2 was used. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 7>
Next, a first retardation film 7 was produced in the same manner as the first retardation film 1 except that the support 3 was used. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 8>
Next, a first retardation film 7 was produced in the same manner as the first retardation film 3 except that a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was used as a support. .
As for the optical properties of the support used here, the in-plane retardation (Re) was 3 nm and the retardation in the thickness direction (Rth) was 45 nm.
Moreover, | Re (400) −Re (700) | was 5 nm, and | Rth (400) −Rth (700) | was 13 nm. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 9>
Next, a first retardation film 9 was produced in the same manner as the first retardation film 1 except that an optically anisotropic layer coating solution having the following composition was used. The optical properties of the produced retardation film are shown in Table 1.
―――――――――――――――――――――――――――――――――――
The following discotic liquid crystalline compound 1.8g
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g
Photopolymerization initiator (the following compound B) 0.04 g
Fluorine-containing polymer (Compound A) 0.01 g
Methyl ethyl ketone 3.9g
―――――――――――――――――――――――――――――――――――

<Preparation of the first retardation film 10>
Next, a first retardation film 10 was produced in the same manner as the first retardation film 9 except that the coating amount of the coating solution was changed. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 11>
75 parts by mass of a rod-like liquid crystalline compound having a polymerizable acrylate group at both ends and having a spacer between the mesogen in the central part and the acrylate, and 1 part by mass of a photopolymerization initiator (manufactured by Chiba Specialty Chemicals, Irgacure Irg184) Then, 25 parts by mass of methyl ethyl ketone as a solvent was mixed, and 10 parts by mass of a chiral agent having polymerizable acrylate groups at both ends was added as a chiral agent to prepare an optically anisotropic layer coating solution.

ここで、ｘは４である。
調製した上記光学異方性層塗布液を、第一の位相差フィルムと同様に、支持体１に鹸化処理、配向膜の塗設、さらにラビング処理した配向膜面に塗布、乾燥、ＵＶ硬化させ、カイラルネマチック（コレステリック）液晶層（光学異方性層）を得た。得られた光学異方性層の厚さは、（４．２）μｍであった。液晶層の螺旋ピッチは１８０ｎｍであり、反射波長は２８０ｎｍであった。作製した位相差フィルムの光学特性は、表１に示す。

Here, x is 4.
Similarly to the first retardation film, the prepared optically anisotropic layer coating solution is saponified and coated with an alignment film on the support 1, and further applied to the rubbed alignment film surface, dried and UV cured. A chiral nematic (cholesteric) liquid crystal layer (optically anisotropic layer) was obtained. The thickness of the obtained optically anisotropic layer was (4.2) μm. The spiral pitch of the liquid crystal layer was 180 nm, and the reflection wavelength was 280 nm. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 12>
Next, a first retardation film 12 was produced in the same manner as the first retardation film 11 except that the support 3 was used. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 13>
Next, a first retardation film 13 was produced in the same manner as the first retardation film 11 except that a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was used as a support. . The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 14>
Next, using the support 1, a laminated film in which a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) is bonded as an optically anisotropic layer with an adhesive is prepared. The laminated film was bonded with an adhesive to produce a first retardation film 14. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of the first retardation film 15>
Next, a first retardation film 15 was produced in the same manner as the first retardation film 1 except that the support 4 was used. The optical properties of the produced retardation film are shown in Table 1.

<Preparation of lower polarizing plate>
Said 1st phase difference films 1-15 and Fujitac TD80UF were affixed on both surfaces of the polarizing film by the roll to roll using the polyvinyl alcohol-type adhesive agent, and the integrated polarizing plate was produced. As shown in FIG. 2, the lamination angle of each film is 90 degrees when the horizontal direction when the display device is viewed from above is a reference (0 °), as shown in FIG. The angle of the protective film slow axis 102 and 106 was set to 90 °. The produced lower polarizing plate was incorporated into a liquid crystal display device so that the optically anisotropic layer (10 in FIG. 1) was in contact with the upper liquid crystal cell substrate (8 in FIG. 1).

<Preparation of upper polarizing plate>
A commercially available cellulose acetate film (Fujitac TD80UF, manufactured by FUJIFILM Corporation, Re value is 3 nm, Rth value is 50 nm) was used as the protective film (105 in FIG. 2). Further, a polycarbonate film (trade name: Pure Ace WR (Teijin Ltd.) is used as a uniaxial retardation film made of a stretched film between the upper polarizing plate (1 in FIG. 1) and the upper liquid crystal cell substrate (5 in FIG. 1). )) One sheet was disposed, and the slow axis in the plane of the retardation film was configured to coincide with the transmission axis of the upper polarizing plate.
As for the optical properties of the polycarbonate film, Re was 155 nm, Rth was 78 nm, and Re (450) / Re (550) = 0.8.

<Evaluation of display characteristics of liquid crystal display device>
In the liquid crystal display device produced as described above, the light leakage and the color change from the front during black display in the azimuth direction 45 degrees and the polar angle direction 60 degrees from the front of the apparatus were visually evaluated according to the following criteria. .

(Judgment criteria for light leakage)
A: No light leakage B: Slight light leakage C: Weak light leakage D: Strong light leakage

(Judgment criteria for color change)
A: Does not feel coloring B: Colors slightly C: Colors weakly D: Colors strongly

  Table 1 shows the optical characteristics and display characteristics evaluation results of each retardation film.

From the evaluation results of Table 1, the retardation of the support is reduced, and the optical characteristics of the retardation film are set to desired values by combining with the optically anisotropic layer. It was made possible to achieve both the light leakage and the color change at a high level.
Furthermore, the liquid crystal display device of the present invention has not only improved display quality but also a viewing angle.

It is the schematic which shows an example of the liquid crystal display device of this invention. It is the schematic which shows an example of the polarizing plate which can be used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper polarizing plate 2 Upper polarizing plate absorption axis direction 3 Second retardation film 4 Second retardation film slow axis direction 5 Liquid crystal cell upper electrode substrate 6 Upper substrate alignment control direction 7 Liquid crystal molecule 8 Below liquid crystal cell Electrode substrate 9 Lower substrate orientation control direction 10 First retardation film 14 Lower polarizing plate 15 Lower polarizing plate absorption axis direction 101 Polarizing plate protective film 102 Polarizing plate protective film slow axis direction 103 Polarizing plate polarizing film 104 Direction of polarizing film absorption axis 105 Polarizing plate protective film 106 Polarizing plate protective film slow axis direction

Claims (16)

A retardation film having a support and at least one optically anisotropic layer,
The front retardation Re and the retardation Rth in the thickness direction of the support satisfy the following formula [1],
The wavelength dispersion of the support satisfies the following formula [2],
The support is made of a cellulose acylate film,
Front retardation Re and thickness direction retardation Rth of the retardation film satisfy the following formula [3], and
A retardation film in which the wavelength dispersibility of the retardation film satisfies the following formula [4].
[1] 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
[2] | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[3] 0 ≦ Re (550) ≦ 10 and 100 ≦ Rth (550) ≦ 300
[4] 1.04 ≦ Rth (450) / Rth (550) ≦ 1.30
[In the formula, Re (λ) is represented by Re (λ) = (nx−ny) × d, and represents a front retardation value (unit: nm) at a wavelength of λ nm. Rth (λ) is represented by Rth (λ) = {(nx + ny) / 2−nz} × d, and represents the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film refractive index. Thickness (nm). ] The retardation film of Claim 1 with which the wavelength dispersion of the said retardation film satisfy | fills following formula [5].
[5] 1.06 ≦ Rth (450) / Rth (550) ≦ 1.30 3. The retardation film according to claim 1, wherein at least one layer of the optically anisotropic layer includes a homeotropically-aligned polymerizable discotic liquid crystalline compound. The retardation film according to claim 1, wherein at least one layer of the optically anisotropic layer contains a cholesteric-aligned polymerizable rod-like liquid crystalline compound. 3. The retardation film according to claim 1, wherein at least one layer of the optically anisotropic layer is made of a polymer or a polymer further stretched after being laminated on the support. The retardation film according to claim 1, wherein at least one of the optically anisotropic layers contains a fluorine-containing surfactant. The support is a cellulose acylate having an acyl substitution degree of 2.85 to 3.00, and at least one compound that reduces Re (λ) and / or Rth (λ) is 0 to the cellulose acylate. The retardation film according to any one of claims 1 to 6, which is obtained by adding at a ratio of 0.01 to 30% by mass. The retardation film according to claim 1, wherein the support has a thickness of 10 to 120 μm. The polarizing plate which has a polarizing film and the protective film provided in both surfaces of this polarizing film, and at least one of this protective film is a phase difference film of any one of Claims 1-8. It has the retardation film of any one of Claims 1-8, and a 2nd retardation film, The front retardation and thickness direction retardation of said 2nd retardation film are the following formulas. The polarizing plate which satisfies [6] and the wavelength dispersion of the second retardation film satisfies the following formula [7].
[6] 70 ≦ Re (550) ≦ 180 and 30 ≦ Rth (550) ≦ 140
[7] 0.7 ≦ Re (450) / Re (550) ≦ 1.0 A liquid crystal display device comprising the retardation film according to claim 1 or the polarizing plate according to claim 9 or 10. Two polarizing plates having mutually perpendicular absorption axes, and a liquid crystal cell provided between the two polarizing plates, the liquid crystal cell being sandwiched between a pair of substrates and the pair of substrates The liquid crystal molecules are aligned in a direction substantially perpendicular to the pair of substrates in a non-driven state in which an external electric field is not applied, and the liquid crystal layer is composed of liquid crystal molecules. The liquid crystal display device which contains the retardation film of any one of 1-8, or the said polarizing plate is a polarizing plate of Claim 9 or 10. The liquid crystal display device further includes a second retardation film, the second retardation film is made of a polymer stretched film, and the front retardation and the retardation in the thickness direction satisfy the following formula [6]. The liquid crystal display device according to claim 11 or 12.
[6] 70 ≦ Re (550) ≦ 180 and 30 ≦ Rth (550) ≦ 140 14. The liquid crystal display device according to claim 11, further comprising a second retardation film, wherein the wavelength dispersion of the second retardation film satisfies the following formula [7]. Liquid crystal display device.
[7] 0.7 ≦ Re (450) / Re (550) ≦ 1.0 The liquid crystal display device further includes a second retardation film, and the second retardation film is a cellulose acylate film, a norbornene film, a polycarbonate film, a polyarylate film, a polyester film, and a polysulfone film. The liquid crystal display device according to claim 11, comprising any one of films. The liquid crystal display device further includes a second retardation film, and the second retardation film is directly laminated on one of the polarizing films in an arrangement in which the absorption axes of the polarizing films are orthogonal to each other. The liquid crystal display device according to any one of 11 to 15.

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