JP4813372B2 - Optical compensation sheet, manufacturing method thereof, polarizing plate and liquid crystal display device - Google Patents

Description

  The present invention relates to an optical compensation sheet, a polarizing plate, and a liquid crystal display device. More specifically, the present invention relates to an optical compensation sheet and polarized light that contribute to improving the viewing angle characteristics of a liquid crystal display device, particularly a vertical alignment (VA) mode liquid crystal display device. The present invention relates to a plate and a liquid crystal display device with improved viewing angle characteristics. The present invention also relates to a method for producing an optical compensation sheet having a good optical compensation capability.

  CRT (Cathode Ray Tube) has been mainly used as a display device used for OA devices such as word processors, notebook personal computers, personal computer monitors, portable terminals, and televisions. In recent years, liquid crystal display devices have been widely used instead of CRTs because of their thinness, light weight, and low power consumption. The liquid crystal display device has a liquid crystal cell and a polarizing plate. The polarizing plate is composed of a protective film and a polarizing film, and is obtained by dyeing a polarizing film made of a polyvinyl alcohol film with iodine, stretching, and laminating both surfaces with a protective film. For example, in a transmissive liquid crystal display device, this polarizing plate is usually attached to both sides of a liquid crystal cell, and one or more optical compensation sheets may be disposed. On the other hand, 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. A liquid crystal cell performs ON / OFF display depending on the alignment state of liquid crystal molecules, and can be applied to any of a transmission type, a reflection type, and a semi-transmission type, such as TN (Twisted Nematic), IPS (In-Plane Switching), Display modes such as OCB (Optically Compensatory Bend), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), and STN (Super Twisted Nematic) are proposed. However, the color and contrast that can be displayed by a conventional liquid crystal display device vary depending on the angle at which the LCD is viewed. For this reason, the viewing angle characteristics of liquid crystal display devices have not yet exceeded the performance of CRT.

  In recent years, as an LCD method for improving the viewing angle characteristics, nematic liquid crystal molecules having negative dielectric anisotropy are used, and the major axis of the liquid crystal molecules is aligned 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 this is 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 plate. In the VA mode, a wider viewing angle characteristic can be obtained by using a negative uniaxial retardation plate (negative c-plate) having an optical axis in a direction perpendicular to the film surface. It is also known that a wider viewing angle characteristic can be realized by using a uniaxially oriented retardation plate (positive a-plate) having a positive refractive index anisotropy having a retardation value of 50 nm ( Non-patent document 1).

  However, when the number of retardation plates is increased in this way, the production cost increases. In addition, since a large number of films are bonded together, it tends to cause not only a decrease in yield but also a deterioration in display quality due to a shift in the bonding angle. Furthermore, since a plurality of films are used, the thickness increases, which may be disadvantageous for thinning the display device.

  Further, a stretched film is usually used for positive a-plate, but when a simple longitudinally stretched film is used, the slow axis of a-plate is the film transport (MD) direction. However, in the VA mode viewing angle compensation, the slow axis of the a-plate must be orthogonal to the MD direction which is the absorption axis of the polarizing plate. Rises significantly. As a method for solving this, it is possible to use a so-called laterally stretched film that is stretched in a direction orthogonal to MD (TD direction). However, the transversely stretched film is apt to cause distortion of a slow axis called bowing, and the yield is high. The cost increases because it does not increase. Furthermore, since an adhesive layer is used for lamination of stretched films, the adhesive layer contracts due to temperature and humidity changes, and defects such as peeling and warping between films may occur. As a method for improving these, a method of producing a-plate by applying a rod-like liquid crystal is known (see Patent Document 2).

  Furthermore, in recent years, a method using a biaxial retardation plate has been proposed instead of the combination of c-plate and a-plate (Non-patent Document 2). By using a biaxial retardation plate, there is an advantage that not only the contrast viewing angle but also the color can be improved. However, the biaxial stretching usually used to produce a biaxial retardation plate is a lateral Similar to stretching, uniform axis control over the entire region of the film is difficult, and the yield does not increase, resulting in an increase in cost.

Therefore, a method for producing a biaxial retardation plate without using stretching by a method of irradiating polarized light to a special cholesteric liquid crystal (Patent Document 3) or a method of irradiating polarized light to a special discotic liquid crystal (Patent Document 4). Was proposed. By this method, various problems caused by stretching can be solved.
However, the biaxial retardation layer produced by the method of irradiating polarized light on such a liquid crystal coated product has a problem in adhesion to the transparent support, and the biaxial retardation layer and the transparent support The optical compensatory sheet as a laminate has a problem to be solved from the viewpoints of suitability for production such as bonding to a polarizing plate and stability over time. Further, in the production of a retardation plate using a liquid crystal coated product, an alignment layer may be disposed immediately below the liquid crystal molecules to align them. However, when an alignment layer such as polyvinyl alcohol or polyimide that is usually used is used, sufficient adhesion between the alignment layer and the layer made of the liquid crystal coating cannot be obtained. There were not a few problems from the viewpoints of production suitability and stability over time.
In addition, when a biaxial retardation plate manufactured by irradiating polarized light on a layer made of such a liquid crystal coating is used for optical compensation, there is a problem in the film surface, that is, there is non-uniformity, and various orientations. There were problems such as unevenness.

Japanese Patent Laid-Open No. 2-176625 JP 2000-304930 A International Publication WO 03/054111 Japanese Patent Laid-Open No. 2002-6138 SID 97 DIGEST Pages 845-848 SID 2003 DIGEST, pages 1208-1211

The problem of the first aspect of the present invention is that the liquid crystal cell is optically compensated optically and can be handled even when the number of bonded sheets is reduced, that is, the optical used for a liquid crystal display element that can be thinned. An optical compensation sheet that is excellent in manufacturing suitability and improved in biaxiality and stability, and a method for stably producing the optical compensation sheet. Another object of the present invention is to provide a polarizing plate and a liquid crystal display element using the optical compensation sheet, particularly a VA mode liquid crystal display element.
The problem of the second aspect of the present invention is that the liquid crystal cell is optically compensated optically and can be accommodated even if the number of sheets to be bonded is small, that is, the optical used for a liquid crystal display element that can be thinned. An optical compensation sheet that is excellent in manufacturing suitability, improved in its biaxiality and film uniformity, and has reduced unevenness, and a stable manufacturing method of the optical compensation sheet. . Moreover, this invention is providing the polarizing plate and liquid crystal display element using this optical compensation sheet, especially the liquid crystal display element of VA mode.

A first aspect of the present invention includes a transparent support, a polymer layer formed on the transparent support by applying and drying a solution having a solvent composition of 20% or more of water, and a polymer layer formed thereon. An optical compensation sheet having an optically anisotropic layer formed from a liquid crystal composition containing at least one kind of liquid crystal compound, the front retardation (Re) of the optically anisotropic layer being not 0, and in-plane retardation. Retardation value measured by making light of wavelength λ nm incident from a direction inclined + 40 ° with respect to the normal direction of the optical compensation sheet with the phase axis as the tilt axis (rotation axis), and the in-plane slow axis as the tilt axis The retardation value measured by making light having a wavelength λ nm incident from a direction inclined by −40 ° with respect to the normal direction of the optical compensation sheet as (rotation axis) is substantially equal, and the polymer layer and the optical difference are Chemically bonded with the isotropic layer That relates to an optical compensation sheet.
The second aspect of the present invention includes a transparent support, a polymer layer on the support, and at least one liquid crystal compound and at least one fluorine-containing horizontal alignment agent on the surface of the polymer layer. An optically anisotropic layer formed from a composition containing the optically anisotropic layer, the front retardation (Re) of the optically anisotropic layer is not 0, and the in-plane slow axis is the tilt axis (rotation axis) The normal direction of the layer plane with the retardation value measured by making light of wavelength λ nm incident from the direction inclined + 40 ° with respect to the normal direction of the layer plane, and the in-plane slow axis as the tilt axis (rotation axis) In particular, the present invention relates to an optical compensation sheet having substantially the same retardation value measured by making light having a wavelength λ nm incident from a direction inclined by −40 ° with respect to.
The fluorine-containing horizontal alignment agent may be a discotic compound or a compound represented by any one of the following general formulas (I) to (III).

式中、Ｒ¹、Ｒ²及びＲ³は各々独立して水素原子又は置換基を表し、少なくとも一つはフッ素原子を含む置換基を表す。Ｘ¹、Ｘ²及びＸ³は単結合又は二価の連結基を表す；

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

式中、Ｒ²¹、Ｒ²²、Ｒ²³、Ｒ²⁴、及びＲ²⁵は各々独立して水素原子又は置換基を表し、少なくとも一つはフッ素原子を含む置換基を表す；

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

式中、Ｒ³¹、Ｒ³²、Ｒ³³、Ｒ³⁴、Ｒ³⁵、及びＲ³⁶は各々独立して水素原子又は置換基を表し、少なくとも一つはフッ素原子を含む置換基を表す。

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom.

  As an embodiment of the present invention, the liquid crystal compound is a polymerizable discotic liquid crystal compound, and the optically anisotropic layer is formed by polymerizing a reactive group of the polymerizable discotic liquid crystal compound. The optical compensation sheet according to the first or second aspect, which is a layer; the liquid crystal compound is a discotic liquid crystal compound, and the optically anisotropic layer is polarized after the discotic liquid crystal compound is horizontally aligned. The optical compensation sheet according to the first or second aspect, wherein the optical compensation sheet is a layer formed by irradiating the above; the optical compensation sheet according to the first or second aspect, wherein the liquid crystal compound is a discotic liquid crystal compound having a triphenylene skeleton; The liquid crystal compound is a polymerizable rod-like liquid crystal compound, and the optically anisotropic layer is formed by polymerizing a reactive group of the polymerizable rod-like liquid crystal compound. The optical compensation sheet according to the first or second aspect, wherein the liquid crystal compound is a rod-like liquid crystal compound, and the optically anisotropic layer is formed by irradiating polarized light after the rod-like liquid crystal compound is cholesterically aligned. The optical compensation sheet according to the first or second aspect, which is an optical layer; the optical layer according to the first or second aspect, wherein the polymer layer is a layer formed from a polymer having a reactive group in a side chain. Compensation sheet; the optical compensation sheet of the first or second aspect, wherein the reactive group of the polymer having a reactive group in the side chain is a reactive group containing an ethylene group; the polymer layer is a side chain The optical compensation sheet according to the first or second aspect, which contains a polymer selected from a polyvinyl alcohol derivative, a poly (meth) acrylate derivative, or a polysaccharide having a reactive group in the transparent support; One side is al The optical compensation sheet according to the first or second aspect, which is a support subjected to resaponification treatment; and the optical compensation according to the first or second aspect, wherein the transparent support contains a cellulose derivative or a cycloolefin derivative. A sheet is provided.

  From another point of view, according to the present invention, a step of forming a polymer layer by applying and drying a solution having a solvent composition of 20% or more of water on a transparent support, and the surface of the polymer layer, Applying a liquid crystal composition comprising at least one discotic liquid crystal compound having a reactive group to align molecules of the discotic liquid crystal compound with an average tilt angle of less than 5 °; The method for producing an optical compensation sheet according to the first aspect in which the steps of polymerizing the molecules of the optically anisotropic layer and forming the optically anisotropic layer are carried out in this order; comprising a solvent composition containing 20% or more of water on the transparent support. Applying a solution and drying to form a polymer layer, and applying a liquid crystal composition containing at least one kind of rod-like liquid crystal compound having a reactive group and at least one chiral agent on the surface of the polymer layer; The The step of cholesteric alignment of molecules of the liquid crystal compound with an average tilt angle of less than 5 ° and the step of polymerizing the molecules of the liquid crystal compound by irradiating polarized light to form an optically anisotropic layer are performed in this order. The method for producing an optical compensation sheet according to the first aspect; when the solution having a solvent composition of 20% or more of water contains a polymer having a reactive group in a side chain, and polymerizes molecules of the liquid crystalline compound At the same time, the method for producing an optical compensation sheet according to the first aspect in which at least a part of the polymer and at least a part of the molecule of the liquid crystal compound react to form a chemical bond; formed on a transparent support Applying a liquid crystal composition containing a discotic liquid crystal compound having at least one polymerizable group and at least one fluorine-containing horizontal alignment agent to the surface of the polymer layer; The step of orienting the molecules of the liquid crystal compound with an average tilt angle of less than 5 ° and the step of polymerizing the molecules of the discotic liquid crystal compound by irradiating polarized light to form the optically anisotropic layer are carried out in this order. A method for producing the optical compensation sheet according to the second aspect; and a rod-like liquid crystal compound having at least one polymerizable group on the surface of the polymer layer formed on the transparent support; and at least one fluorine-containing horizontal alignment agent; A step of applying a liquid crystal composition containing a liquid crystal, a step of cholesteric alignment of the molecules of the rod-like liquid crystal compound with an average inclination angle of less than 5 °, and a polymer of the molecules of the rod-like liquid crystal compound by irradiating polarized light. There is provided a method for producing an optical compensation sheet according to the second aspect, wherein the steps of forming the conductive layer are performed in this order.

  From another viewpoint, according to the present invention, a polarizing plate having at least one optical compensation sheet of the first or second aspect and a polarizer; the optical compensation sheet of the first or second aspect, Alternatively, a liquid crystal display device including a polarizing plate having the optical compensation sheet of the first or second aspect and a polarizer; and the liquid crystal display device in which a display mode is a VA mode are provided.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.
In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. Moreover, unless otherwise indicated,% showing content means the mass%.

  In this specification, the Re retardation value and the Rth retardation value are calculated based on the following. Re (λ) and Rth (λ) respectively represent in-plane retardation and retardation in the thickness direction at wavelength λ. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth (λ) is incident on light having a wavelength of λ nm from the direction inclined by + 40 ° with respect to the normal direction of the film with Re (λ) and the slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). The retardation value measured in this way, and the retardation value measured by making light of wavelength λ nm incident from a direction inclined −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis KOBRA 21ADH is calculated based on the retardation value measured in (1). At this time, it is necessary to input an assumed value of average refractive index and a film thickness. KOBRA 21ADH calculates nx, ny, and nz in addition to Rth (λ). The average refractive index of 1.48 is used for cellulose acetate, but the values of polymer films for typical optical applications other than cellulose acetate include cycloolefin polymer (1.52), polycarbonate (1.59), poly Values such as methyl methacrylate (1.49) and polystyrene (1.59) can be used. As the average refractive index value of other existing polymer materials, a polymer handbook (John Wiley & Sons, Inc.) or a catalog value of a polymer film can be used. Further, in the case of a material whose average refractive index is unknown, it can be measured using an Abbe refractometer. In this specification, λ refers to 545 ± 5 nm or 590 ± 5 nm unless otherwise specified.

  In this specification, “substantially” for the angle means that the error from the exact angle is within a range of less than ± 10 °. Furthermore, the error from the exact angle is preferably less than 4 °, more preferably less than 3 °. “Substantially equal” for retardation means that the difference in retardation is within ± 10%.

[Optical compensation sheet]
FIG. 1 is a schematic sectional view of an example of the optical compensation sheet according to the first embodiment of the present invention. The optical compensation sheet according to the first aspect of the present invention has an optically anisotropic layer 12 on a transparent support 11. Between the transparent support 11 and the optically anisotropic layer 12, a polymer layer 13 that functions as an alignment layer for controlling the alignment of liquid crystalline molecules in the optically anisotropic layer 12 is disposed. The polymer layer 13 is a polymer layer formed by applying and drying a solution having a solvent composition of 20% or more of water, and is chemically bonded to the optically anisotropic layer 12. Therefore, the polymer layer 13 and the optically anisotropic layer 12 have high adhesiveness, and are not easily peeled off during washing treatment such as water washing or chemical treatment such as saponification treatment, and the handling property is good. Further, the optical properties of the optically anisotropic layer 12 are such that the front retardation (Re) is not 0, and the in-plane slow axis is the tilt axis (rotation axis) and + 40 ° with respect to the normal direction of the optical compensation sheet. A retardation value measured by making light of wavelength λ nm incident from an inclined direction, and a direction inclined by −40 ° with respect to the normal direction of the optical compensation sheet with the in-plane slow axis as the inclined axis (rotating axis) Since the retardation value measured by making light having a wavelength λ nm incident is adjusted to be substantially equal, a liquid crystal cell, particularly a VA mode liquid crystal cell can be compensated accurately. Note that “Re is not 0” means that Re is not less than 3 nm.

  FIG. 2 is an example of the optical compensation sheet according to the second embodiment of the present invention. The optical compensation sheet according to the second aspect of the present invention has a polymer layer 13 ′ on the transparent support 11 and an optically anisotropic layer 12 ′ on the polymer layer 13 ′. The polymer layer 13 'has a function as an alignment layer for controlling the alignment of the liquid crystalline molecules in the optically anisotropic layer 12'. The optically anisotropic layer 12 ′ was formed by applying a composition containing at least one liquid crystal compound and at least one fluorine-containing horizontal alignment agent to the surface of the polymer layer 13 ′ to align the molecules of the liquid crystal compound. It is a layer formed after fixing. By aligning the molecules of the liquid crystal compound in the presence of the fluorine-containing horizontal alignment agent, the unevenness of the film surface is reduced and the uniformity of the surface is improved, and the uniformity of the alignment state of the liquid crystal molecules is also improved. The optically anisotropic layer 12 ′ exhibits an excellent optical compensation capability. Further, the optical properties of the optically anisotropic layer 12 ′ are such that the front retardation (Re) is not 0, and the in-plane slow axis is the tilt axis (rotation axis) and +40 with respect to the normal direction of the optical compensation sheet. A retardation value measured by making light having a wavelength λ nm incident from a tilted direction, and a direction tilted by −40 ° with respect to the normal direction of the optical compensation sheet with the in-plane slow axis as the tilt axis (rotation axis) Since the retardation value measured by making light having a wavelength of λ nm incident is adjusted to be substantially equal, a liquid crystal cell, particularly a VA mode liquid crystal cell can be compensated accurately. “Front retardation (Re) is not 0” means that Re is not less than 3 nm.

[Polarizer]
3A to 3D are schematic cross-sectional views of a polarizing plate having the optical compensation sheet of the first or second aspect of the present invention. In general, the polarizing plate can be prepared by dyeing a polarizing film made of a polyvinyl alcohol film with iodine and performing stretching to obtain the polarizing film 21, and laminating protective films 22 and 23 on both sides thereof. it can. Since the optical compensation sheet according to the first or second aspect of the present invention has a support made of a polymer film or the like that supports the optically anisotropic layer, this support is used as it is for at least one of the protective films 22 and 23. be able to. At this time, the optically anisotropic layer 12 (or 12 ′) is disposed on the polarizing layer 21 side (that is, the optically anisotropic layer 12 (or 12 ′) is closer to the polarizing layer 21 than the support 11). Alternatively, the optically anisotropic layer 12 (or 12 ′) may be disposed on the side opposite to the polarizing layer 21 (that is, farther from the polarizing layer 21 than the support 11), as shown in FIG. As described above, the optically anisotropic layer 12 (or 12 ′) is preferably on the side opposite to the polarizing layer 21. Further, as shown in FIG. 3B, it is also possible to bond to the outside of one protective film 22 of the polarizing layer 21 via an adhesive or the like.

  3C and 3D are configuration examples of a polarizing plate in which another functional layer 24 is further arranged on the polarizing plate having the configuration shown in FIG. FIG. 3C shows a configuration in which another functional layer 24 is arranged on the protective film 23 arranged on the opposite side with the optical compensation sheet of the first or second aspect of the present invention and the polarizing layer 21 in between. FIG. 3D is an example, and is a configuration example in which another functional layer 24 is arranged on the optical compensation sheet of the first or second aspect of the present invention. Examples of other functional layers are not particularly limited, and examples thereof include functional layers that impart various characteristics, such as λ / 4 layers, antireflection layers, and hard coat layers. These layers may be bonded together with, for example, an adhesive as a member such as a λ / 4 plate, an antireflection film, or a hard coat film. In the configuration example of FIG. Alternatively, another functional layer 24 can be formed on the optical compensation sheet (optically anisotropic layer 12 or 12 ′) of the second embodiment, and then bonded to the polarizing layer 21. Further, the protective film 23 on the opposite side to the optical compensation sheet of the first or second aspect of the present invention can be replaced with other functional films such as a λ / 4 plate, an antireflection film, and a hard coat film. .

  When producing a polarizing plate by laminating a polarizing film and a protective film, a total of three films of a pair of protective film and polarizing film can be bonded together in a roll-to-roll manner. This roll-to-roll is a preferable method as a manufacturing process of a polarizing plate because it is difficult to cause dimensional change and curling of the polarizing plate as well as productivity, and can impart high mechanical stability.

[Liquid Crystal Display]
FIG. 4 shows an example of the liquid crystal display device of the present invention. The liquid crystal display device includes a liquid crystal cell 35 having a nematic liquid crystal sandwiched between upper and lower electrode substrates, and a pair of polarizing plates 36 and 37 disposed on both sides of the liquid crystal cell, and at least one of the polarizing plates. Uses the polarizing plate of the present invention shown in FIG. When using the polarizing plate of this invention, it arrange | positions so that an optically anisotropic layer may exist between a polarizing layer and the electrode substrate of a liquid crystal cell. Nematic liquid crystal molecules are controlled so as to be in a predetermined alignment state by providing an alignment layer applied on the electrode substrate and a rubbing process on the surface or a structure such as a rib.

  One or more light control films 34 such as a brightness enhancement film and a diffusion film may be provided below the liquid crystal cell sandwiched between the polarizing plates. Furthermore, the light control film has a reflection plate 32 and a light guide plate 33 for irradiating light emitted from the cold cathode tubes 31 to the front. Instead of a backlight unit comprising a cold cathode tube and a light guide plate, recently, a direct type backlight in which several cold cathode tubes are arranged under a liquid crystal cell, an LED backlight using an LED as a light source, or an organic EL Backlights that emit surface light using inorganic EL or the like are also used, but any of the optical films of the present invention is also effective in backlights.

  Further, although not shown in the figure, in the reflective liquid crystal display device, only one polarizing plate is required on the observation side, and a reflective film is provided on the back surface of the liquid crystal cell or on 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.

Next, materials used for the production of the optical compensation sheet according to the first and second aspects of the present invention, production methods, and the like will be described in detail.
The optical compensation sheet of the first and second aspects of the present invention (hereinafter referred to as the present invention means that both the first and second aspects are included unless otherwise specified) is a transparent support, It has a molecular layer and the optically anisotropic layer, and the optically anisotropic layer contributes to increasing the contrast viewing angle of the liquid crystal display device and eliminating image coloring of the liquid crystal display device. In the optical compensation sheet of the present invention, 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 components can be reduced. In other words, this aspect contributes to the thinning of the liquid crystal display device.

  In the present invention, an optically anisotropic layer made of a liquid crystal compound is formed on an optically uniaxial or biaxial transparent support made of a polymer, thereby significantly improving the optical characteristics of the liquid crystal display device. Can do.

[Optically anisotropic layer made of liquid crystal compound]
In the present invention, as described above, the optically anisotropic layer formed by curing a liquid crystal layer containing a liquid crystal compound contributes to optical compensation of the liquid crystal cell. Of course, the optically anisotropic layer alone may have sufficient optical compensation ability, or may be an aspect satisfying the optical characteristics required for optical compensation in combination with other layers (for example, a support). The optically anisotropic layer is formed from a composition containing at least one liquid crystal compound. In general, liquid crystal compounds can be classified into a rod-shaped type and a disk-shaped type based on their molecular shapes. In addition, there are low and high molecular types, respectively. Polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used, but a rod-like liquid crystal compound or a discotic liquid crystal compound is preferably used. Two or more kinds of rod-like liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used. It is more preferable to use a rod-like liquid crystal compound or a discotic liquid crystal compound having a reactive group because temperature change and humidity change can be reduced. In the case of a mixture, at least one reactive group in one liquid crystal molecule is 2 More preferably, the above is present. The liquid crystal compound may be a mixture of two or more types, and in that case, at least one preferably has two or more reactive groups. The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, and more preferably 0.5 to 10 μm.

  Examples of the rod-like liquid crystal compound include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the low-molecular liquid crystal compounds as described above, high-molecular liquid crystal compounds can also be used. The polymer liquid crystal compound is a polymer compound obtained by polymerizing a rod-like liquid crystal compound having a low molecular reactive group. The rod-like liquid crystal compound having a low-molecular reactive group that is particularly preferably used is a rod-like liquid crystal compound represented by the following general formula (IV).

Formula (IV): Q ¹ -L ¹ -A ¹ -L ³ -ML ⁴ -A ² -L ² -Q ²
Wherein, Q ¹ and Q ² respectively represent a reactive group, the L ^1, L ^2, L ³ and L ⁴ respectively represent a single bond or a divalent linking group, L ³ and At least one of L ⁴ represents —O—, —O—CO—, —CO—O— or —O—CO—O—. A ¹ and A ² each independently represent a spacer group having 2 to 20 carbon atoms. M represents a mesogenic group.

Hereinafter, the rod-like liquid crystal compound having a reactive group represented by the general formula (IV) will be described in more detail. In the formula, Q ¹ and Q ² are each independently a reactive group. The polymerization reaction of the reactive group is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the reactive group is preferably a reactive group capable of an addition polymerization reaction or a condensation polymerization reaction. Examples of reactive groups are shown below.

Examples of the divalent linking group represented by L ¹ , L ² , L ³ and L ⁴ include —O—, —S—, —CO—, —NR ² —, —CO—O—, and —O—CO. —O—, —CO—NR ² —, —NR ² —CO—, —O—CO—, —O—CO—NR ² —, —NR ² —CO—O—, and NR ² —CO—NR ^2. A divalent linking group selected from the group consisting of-is preferred. R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. In the formula (IV), Q ¹ -L ¹ and Q ² -L ² -are CH ₂ ═CH—CO—O—, CH ₂ ═C (CH ₃ ) —CO—O—, and CH ₂ ═C ( Cl) -CO-O-CO- O- are _{preferable, CH 2 = CH-CO-} O- is more preferable.

A ¹ and A ² represent spacer groups having 2 to 20 carbon atoms. An aliphatic group having 2 to 12 carbon atoms is preferable, and an alkylene group is particularly preferable. The spacer group is preferably chain-like and may contain oxygen atoms or sulfur atoms that are not adjacent to each other. The spacer group may have a substituent and may be substituted with a halogen atom (fluorine, chlorine, bromine), a cyano group, a methyl group, or an ethyl group.

Examples of the mesogenic group represented by M include all known mesogenic groups. In particular, a group represented by the following general formula (V) is preferable.
Formula (V): - (- W 1 -L 5) n-W 2 -
In the formula, W ¹ and W ² each independently represent a divalent cycloaliphatic group, a divalent aromatic group or a divalent heterocyclic group, L ⁵ represents a single bond or a linking group, and Specific examples of the group include specific examples of groups represented by L ^{1 to} L ⁴ in the formula (IV), —CH ₂ —O—, and —O—CH ₂ —. n represents 1, 2 or 3.

W ¹ and W ² include 1,4-cyclohexanediyl, 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5diyl, 1,3,4-thiadiazole-2,5-diyl, 1,3,4-oxadiazole-2,5-diyl, naphthalene-2,6-diyl, naphthalene-1,5-diyl, thiophene-2,5-diyl, pyridazine-3,6-diyl . In the case of 1,4-cyclohexanediyl, there are trans isomers and cis isomers, but either isomer may be used, and a mixture in any proportion may be used. More preferably, it is a trans form. W1 and W2 may each have a substituent. Examples of the substituent include a halogen atom (fluorine, chlorine, bromine, iodine), a cyano group, an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, etc.), and an alkoxy group having 1 to 10 carbon atoms. (Methoxy group, ethoxy group, etc.), C1-10 acyl group (formyl group, acetyl group, etc.), C1-10 alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, etc.), carbon atom Examples thereof include an acyloxy group having 1 to 10 (acetyloxy group, propionyloxy group, etc.), nitro group, trifluoromethyl group, difluoromethyl group and the like.

  Preferred examples of the basic skeleton of the mesogenic group represented by the general formula (V) are shown below. These may be substituted with the above substituents.

  Examples of the compound represented by the general formula (IV) are shown below, but the present invention is not limited thereto. In addition, the compound represented by general formula (IV) is compoundable by the method as described in Japanese translations of PCT publication No. 11-513019.

  The discotic liquid crystal compounds that can be used in the present invention include various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, quarterly chemistry). Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); Zhang et al., J. Am.Chem.Soc., Vol.116, page 2655 (1994)). Of these, a discotic liquid crystal compound having a triphenylene skeleton is preferable. The polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.

The discotic liquid crystal compound preferably has a reactive group so that it can be fixed by polymerization. For example, a structure in which a reactive group is bonded as a substituent to the disk-shaped core of a disk-shaped liquid crystal compound is conceivable. However, when a reactive group is directly bonded to the disk-shaped core, it is difficult to maintain the alignment state in the polymerization reaction. become. Therefore, a structure having a linking group between the discotic core and the reactive group is preferable. That is, the discotic liquid crystal compound having a reactive group is preferably a compound represented by the following general formula (VI).
Formula (VI): D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a reactive group, and n is an integer of 4 to 12.

  In the formula (VI), preferred specific examples of the discotic core (D), the divalent linking group (L), and the reactive group (P) are (D1) described in JP-A No. 2001-4837, respectively. To (D15), (L1) to (L25), (P1) to (P18), and the disk-shaped core (D), divalent linking group (L) and reactive group ( The contents regarding P) can be preferably applied here.

  Further, the discotic liquid crystalline molecule preferably has a photosensitive functional group. The reaction of the photosensitive functional group is induced by light (see Photofunctional Molecular Science, Chapter 2, Kazuyuki Horie, Shuji Ushiki, Kodansha, 1992). Reactions include sigma bond cleavage, C═C double bond reaction and C═O double bond reaction. It is desirable that the refractive index of the discotic liquid crystalline molecule is changed by the reaction, and for this purpose, sigma bond cleavage or C═C double bond reaction is preferred, and C═C double bond reaction is particularly preferred. More preferably, the C═C double bond is conjugated with a benzene ring. The double bond conjugated with the benzene ring is dimerized by forming a 4-membered ring between the two molecules by light irradiation. As a result, the refractive index of the discotic liquid crystal molecules changes. The discotic liquid crystal molecule particularly preferably has a monovalent group containing a benzene ring and a double bond conjugated with the benzene ring as a substituent of the discotic nucleus. The benzene ring and the double bond conjugated with the benzene ring are preferably contained in a linking group between the discotic nucleus of the discotic liquid crystalline molecule and the reactive group. A discotic liquid crystalline molecule represented by the following formula (VII) is particularly preferable.

In the formula (VII), A ¹ is CX ¹ or N. CX ¹ is preferable to N. X ¹ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. X ¹ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the hydrogen atom or the number of carbon atoms is It is more preferably 1 to 3 alkyl groups, and most preferably a hydrogen atom. In the formula (VII), A ² is CX ² or N. CX ² is preferred over N. X ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, or is bonded to Y to form a 5-membered or 6-membered ring. To do. X ² is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the hydrogen atom or the number of carbon atoms is It is more preferably 1 to 3 alkyl groups, and most preferably a hydrogen atom. The ring formed by combining X ² and Y is preferably a hydrocarbon ring rather than a heterocyclic ring, and more preferably an aliphatic ring rather than an aromatic ring. Further, a 6-membered ring is preferable to a 5-membered ring.

In the formula (VII), Y represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an acyl group having 2 to 13 carbon atoms, a carbon atom It is an alkylamino group having 1 to 12 carbon atoms or an acyloxy group having 2 to 13 carbon atoms, or is bonded to X ² to form a 5-membered or 6-membered ring. Y is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a hydrogen atom or the number of carbon atoms is 1. More preferably, it is an alkyl group of ˜3, and most preferably a hydrogen atom. In the formula (VII), Z is a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an acyl group having 2 to 13 carbon atoms, or 1 carbon atom. Or an alkylamino group having 12 carbon atoms or an acyloxy group having 2 to 13 carbon atoms. Z is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and an alkyl group having 1 to 3 carbon atoms. Even more preferred.

In the formula (VII), L ¹ is a divalent group selected from the group consisting of —O—, —CO—, —S—, —NH—, an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and combinations thereof. It is a linking group. The example of the bivalent coupling group which consists of a combination is shown below. The left side is bonded to the benzene ring, and the right side is bonded to the reactive group (Q). AL means an alkylene group, an alkenylene group or an alkynylene group, and AR means an arylene group.
L-1: -AL-CO-O-AL-
L-2: -AL-CO-O-AL-O-
L-3: -AL-CO-O-AL-O-AL-
L-4: -AL-CO-O-AL-O-CO-
L-5: -CO-AR-O-AL-
L-6: -CO-AR-O-AL-O-
L-7: -CO-AR-O-AL-O-CO-
L-8: -CO-NH-AL-
L-9: -NH-AL-O-
L-10: —NH—AL—O—CO—
L-11: -O-AL-
L-12: -O-AL-O-
L-13: -O-AL-O-CO-
L-14: -O-AL-O-CO-NH-AL-
L-15: -O-AL-S-AL-
L-16: -O-CO-AL-AR-O-AL-O-CO-
L-17: -O-CO-AR-O-AL-CO-
L-18: -O-CO-AR-O-AL-O-CO-
L-19: -O-CO-AR-O-AL-O-AL-O-CO-
L-20: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L-21: -S-AL-
L-22: -S-AL-O-
L-23: -S-AL-O-CO-
L-24: -S-AL-S-AL-
L-25: -S-AR-AL-

In the formula (VII), L ² is a single bond or 1,4-phenylene. A single bond is preferred over 1,4-phenylene. In the formula (VII), Q is a reactive group. The reactive group (Q) is determined according to the type of polymerization reaction. Examples of the reactive group (Q) are shown below.

The reactive group (Q) is preferably an unsaturated reactive group (Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated reactive group, and an ethylenic group. More preferably, it is an unsaturated reactive group (Q1-Q6). In the formula (VII), a is 1, 2, 3 or 4. a is preferably 1, 2 or 3, more preferably 1 or 2, and still more preferably 1. When a is 1, -L ¹ -Q is preferably bonded to the 4-position of the benzene ring. In the formula (VII), b is 0, 1, 2 or 3. b is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0. In the formula (VII), a + b is 1, 2, 3 or 4. Six Rs in the formula (VII) may be different but are preferably the same. Hereinafter, examples of the discotic liquid crystalline molecules represented by the formula (VII) are represented by R.

An example of the optically anisotropic layer is that a rod-like liquid crystal compound molecule having a reactive group is cholesterically aligned on the polymer layer with an average tilt angle of less than 5 °, and then irradiated with polarized light to irradiate optically. It can be produced by simultaneously carrying out the expression of axiality and the polymerization of the molecules of the liquid crystal compound.
When using a rod-like liquid crystal compound having a reactive group, it is necessary to distort the cholesteric alignment by irradiation with polarized light in order to develop biaxiality. As a method of distorting the alignment by irradiation with polarized light, a method using a dichroic liquid crystalline polymerization initiator (International Publication WO03 / 054111) or a rod-like liquid crystal compound having a photoalignable functional group such as a cinnamoyl group in the molecule is used. The method to be used (JP 2002-6138 A) is mentioned.

In another example of the optically anisotropic layer, molecules of a discotic liquid crystal compound having a reactive group are aligned on the polymer layer with an average tilt angle of less than 5 °, and then irradiated with polarized light. It can be produced by simultaneously carrying out the expression of optical biaxiality and the polymerization of the molecules of the liquid crystal compound.
When using a discotic liquid crystal compound having a reactive group, it may be fixed in any alignment state of horizontal alignment, vertical alignment, and twist alignment, but may have symmetry with respect to the normal direction of the film. Preferably, horizontal alignment is even more preferable. Horizontal alignment means that the disc surface of the core of the discotic liquid crystal compound is parallel to the horizontal plane of the transparent support, but it is not required to be strictly parallel. In this specification, the horizontal plane is defined as the horizontal plane. It shall mean an orientation with an inclination angle of less than 10 °. In particular, it is more preferably less than 5 °.

  The front retardation (Re) of the optically anisotropic layer is not zero. Re is not 0 means that Re is not less than 3 nm. Re is preferably 3 or more and 250 nm or less, more preferably 7.5 to 100 nm, and still more preferably 15 to 80 nm. Rth is preferably 30 to 500 nm in total with Rth of the transparent support, more preferably 40 to 400 nm, and even more preferably 100 to 350 nm.

  When two or more optically anisotropic layers made of a liquid crystal compound are laminated, the combination of the liquid crystal compounds is not particularly limited, and a laminate of layers made of all discotic liquid crystal compounds, a laminate of layers made of all rod-like liquid crystal compounds. Or a laminate of a layer made of a discotic liquid crystal compound and a layer made of a rod-like liquid crystal compound. The combination of the alignment states of the layers is not particularly limited, and optically anisotropic layers having the same alignment state may be stacked, or optically anisotropic layers having different alignment states may be stacked.

  The optically anisotropic layer is preferably formed by applying a coating liquid containing a liquid crystal compound and the following polymerization initiator and other additives on the alignment layer. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating solution can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, wire bar coating method).

[Fixation of alignment state of liquid crystal compound]
The aligned liquid crystal compound is preferably fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of a reactive 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 ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group 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), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight, based on the solid content of the coating solution. Light irradiation for the polymerization of the liquid crystal compound is preferably performed using ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~10J / 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.

[Optical alignment by polarized irradiation]
In the present invention, in-plane retardation of the optically anisotropic layer may be generated by irradiation with polarized light. This polarized light irradiation may be performed at the same time as the photopolymerization process in the above-described orientation fixing, or may be further fixed by non-polarized light irradiation after first polarized light irradiation, or fixed first by non-polarized light irradiation. The irradiation with polarized light may be performed after conversion. In order to obtain a large retardation, it is preferable to irradiate polarized light alone or first. The polarized light irradiation is preferably performed in an inert gas atmosphere having an oxygen concentration of 3% or less, more preferably 0.5% or less. For polarized light irradiation, ultraviolet polarized light irradiation is preferable, particularly polarized light irradiation having a peak at 365 ± 10 nm is preferable, and polarized light irradiation having a peak at 365 ± 5 nm is more preferable. The irradiation energy is preferably ^{20mJ / cm 2 ~10J / cm 2} , further preferably 100 to 800 mJ / cm ^2. The illuminance is preferably 20 to 1000 mW / cm ^2, more preferably 50 to 500 mW / cm ^2, further preferably 100 to 350 mW / cm ^2. Although there is no restriction | limiting in particular about the kind of liquid crystalline compound hardened | cured by polarized light irradiation, The liquid crystalline compound which has an ethylenically unsaturated group as a reactive group is preferable.
Note that the optically anisotropic layer exhibiting in-plane retardation generated by photo-alignment by polarized light irradiation is particularly excellent for optically compensating a VA mode liquid crystal display device.

[Horizontal alignment agent]
In the second aspect of the present invention, a fluorine-containing horizontal alignment agent is contained together with the liquid crystal compound in the composition for forming an optically anisotropic layer. Also in the first aspect of the present invention, the composition for forming an optically anisotropic layer may contain a fluorine-containing horizontal alignment agent together with the liquid crystal compound. By using at least one fluorine-containing horizontal alignment agent in combination, the molecules of the liquid crystal compound can be substantially horizontally aligned, and an optically anisotropic layer having uniform optical properties can be formed. The fluorine-containing horizontal alignment agent also contributes to the reduction of film surface unevenness. In the present invention, “horizontal alignment” means that in the case of a rod-like liquid crystal, the molecular long axis and the horizontal plane of the transparent support are parallel, and in the case of a disc-like liquid crystal, the disc surface of the core of the disc-like liquid crystal compound and This means that the horizontal plane of the transparent support is parallel, but it is not required to be strictly parallel. In the present specification, it means an orientation having an inclination angle of less than 10 degrees with the horizontal plane. . The inclination angle is preferably 0 to 5 degrees, more preferably 0 to 3 degrees, further preferably 0 to 2 degrees, and most preferably 0 to 1 degree.

  As the fluorine-containing horizontal alignment agent, a discotic compound represented by any one of the following general formulas (I) to (III) is preferable. Hereinafter, general formulas (I) to (III) will be described.

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ³ represent a single bond or a divalent linking group.

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom.

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom.

The compounds represented by general formulas (I) to (III) will be described in detail below. First, the compound represented by general formula (I) is demonstrated.
The substituent represented by each of R ¹ , R ² , and R ³ is an alkyl group (preferably an alkyl group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms). And examples thereof include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, an n-octyl group, an n-decyl group, an n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group). A group (preferably an alkenyl group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a 2-butenyl group, or a 3-pentenyl group. An alkynyl group (preferably an alkynyl group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, and particularly preferably 2 to 20 carbon atoms). For example, a propargyl group, 3-pentynyl group, etc.), an aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms). A phenyl group, a p-methylphenyl group, a naphthyl group, etc.), a substituted or unsubstituted amino group (preferably having 0 to 40 carbon atoms, more preferably 0 to 30 carbon atoms, and particularly preferably carbon number). 0 to 20 amino groups such as an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and an anilino group)

An alkoxy group (preferably an alkoxy group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms, particularly preferably 6 to 20 carbon atoms, and examples thereof include a phenyloxy group and a 2-naphthyloxy group. An acyl group (preferably an acyl group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms, such as an acetyl group, a benzoyl group, a formyl group, and a pivaloyl group. Etc.), an alkoxycarbonyl group (preferably having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, and particularly preferably carbon number) To 20 alkoxy groups such as methoxycarbonyl group and ethoxycarbonyl group), aryloxycarbonyl groups (preferably having 7 to 40 carbon atoms, more preferably having 7 to 30 carbon atoms, and particularly preferably carbon atoms). An aryloxycarbonyl group having 7 to 20 carbon atoms, such as a phenyloxycarbonyl group, and an acyloxy group (preferably having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, and particularly preferably 2 carbon atoms). ˜20 acyloxy groups such as an acetoxy group and a benzoyloxy group)

An acylamino group (preferably an acylamino group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, such as an acetylamino group and a benzoylamino group), alkoxycarbonyl An amino group (preferably an alkoxycarbonylamino group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, such as a methoxycarbonylamino group), aryloxy Carbonylamino group (preferably an aryloxycarbonylamino group having 7 to 40 carbon atoms, more preferably 7 to 30 carbon atoms, particularly preferably 7 to 20 carbon atoms, such as a phenyloxycarbonylamino group) Sulfonylamino group (preferably having 1 to 40 carbon atoms, more preferred Or a sulfonylamino group having 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, such as a methanesulfonylamino group and a benzenesulfonylamino group, and a sulfamoyl group (preferably having a carbon number of 0 to 40). More preferably, it is a sulfamoyl group having 0 to 30 carbon atoms, particularly preferably 0 to 20 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group. ), A carbamoyl group (preferably a carbamoyl group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, for example, an unsubstituted carbamoyl group, a methylcarbamoyl group, diethylcarbamoyl group Group, phenylcarbamoyl group, etc.),

An alkylthio group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, such as a phenylthio group), a sulfonyl group (preferably having 1 to 1 carbon atoms). 40, more preferably a sulfonyl group having 1 to 30 carbon atoms, particularly preferably a sulfonyl group having 1 to 20 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 40, more Preferably it is C1-C30, Most preferably, it is C1-C20 sulfinyl group, for example, a methane sulfinyl group, a benzene sulfinyl group, etc., a ureido group (preferably C1-C40, more preferable) Is a ureido group having 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, such as an unsubstituted ureido group or methylurea. And phosphoric acid amide groups (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms), For example, a diethylphosphoric acid amide group, a phenylphosphoric acid amide group etc. are mentioned), a hydroxy group, a mercapto group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), a cyano group, a sulfo group, a carboxyl group , A nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (preferably a heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms such as a nitrogen atom, an oxygen atom, A heterocyclic group having a heteroatom such as a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group Morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, 1,3,5-triazyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms). Particularly preferred is a silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. These substituents may be further substituted with these substituents. Further, when two or more substituents are present, they may be the same or different. If possible, they may be bonded to each other to form a ring.
Of the above, the substituents represented by R ¹ , R ² and R ³ are preferably an alkyl group, an alkenyl group, an alkynyl group, an aryl group and a heterocyclic group.

At least one of R ¹ , R ² and R ³ represents a substituent containing a fluorine atom. Each group represented by R ¹ , R ² and R ³ may have a substituent other than a fluorine atom, and examples of the substituent include an alkyl group, an aryl group, a substituted or unsubstituted amino group, An alkoxy group, an alkylthio group or a halogen atom is preferable, and a fluorine atom is more preferable. That is, all of R ¹ , R ² and R ³ are each preferably a substituent containing a fluorine atom.

The divalent linking groups represented by X ¹ , X ² and X ³ are each an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, —CO—, —NR ^a — ( R ^a is ^a divalent linking group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —S—, —SO—, —SO 2 — and combinations thereof. It is preferable. The divalent linking group is a combination of at least two divalent linking groups selected from an alkylene group, a phenyl group, —CO—, —NR ^a —, —O—, —S—, —SO 2 — and a group thereof. More preferably, The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms of the divalent aromatic group is preferably 6-10. An alkylene group, an alkenylene group and a divalent aromatic group are preferably groups exemplified as substituents for the aforementioned R ¹ , R ² and R ³ (for example, alkyl groups, halogen atoms, cyano, alkoxy groups, An acyloxy group).

  Among the compounds represented by the general formula (I), compounds represented by the following general formula (Ia) or (Ib) are particularly preferable.

In the formula, R ^1a , R ^2a and R ^3a each represents a hydrogen atom or a substituent, and at least one of them represents a substituent containing a fluorine atom. X ^1a , X ^2a and X _3a each represent —NH—, —O— or —S—, and m1a, m2a and m3a each represent an integer of 1 to 3.

In the formula, Rf ¹ , Rf ² and Rf ³ each represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal, and Y ¹ , Y ² and Y ³ are an alkylene group, —CO—, —NH It represents a group in which at least two divalent linking groups selected from —, —O—, —S—, —SO ₂ — and the group thereof are combined.

First, the compound represented by the general formula (Ia) will be described.
The substituents represented by R ^1a , R ^2a and R ^3a have the same meanings as R ¹ , R ² and R ³ in the general formula (I), and their preferred ranges are also the same. The substituents represented by R ^1a , R ^2a and R ^3a are particularly preferably alkoxy groups having a CF ₃ group or a CF ₂ H group at the terminal. The alkyl chain contained in the alkoxy group may be linear or branched, preferably has 4 to 20 carbon atoms, more preferably has 4 to 16 carbon atoms, and is particularly preferable. Is 6-16. The alkoxy group having a CF ₃ group or a CF ₂ H group at the terminal is an alkoxy group in which part or all of the hydrogen atoms contained in the alkoxy group are substituted with fluorine atoms. 50% or more of the hydrogen atoms in the alkoxy group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. Examples of alkoxy groups having a CF ₃ group or a CF ₂ H group at the ends represented by R ^1a , R ^2a and R ^3a are shown below.

R ¹ : n-C ₈ F ₁₇ —O—
_{^{R 2: n-C 6 F}} 13 -O-
_{^{R 3: n-C 4 F}} 9 -O-
_{^{R 4: n-C 8 F}} 17 - (CH 2) 2 -O- (CH 2) 2 -O-
_{^{R 5: n-C 6 F}} 13 - (CH 2) 2 -O- (CH 2) 2 -O-
_{^{R 6: n-C 4 F}} 9 - (CH 2) 2 -O- (CH 2) 2 -O-
_{^{R 7: n-C 8 F}} 17 - (CH 2) 3 -O-
_{^{R 8: n-C 6 F}} 13 - (CH 2) 3 -O-
_{^{R 9: n-C 4 F}} 9 - (CH 2) 3 -O-
R ¹⁰ : H— (CF ₂ ) ₈ —O—
R ¹¹ : H— (CF ₂ ) ₆ —O—
R ¹² : H— (CF ₂ ) ₄ —O—
R ¹³ : H— (CF ₂ ) ₈ — (CH ₂ ) —O—
R ¹⁴ : H— (CF ₂ ) ₆ — (CH ₂ ) —O—
_{^{R 15: H- (CF 2)}} 4 - (CH 2) -O-
R ¹⁶ : H— (CF ₂ ) ₈ — (CH ₂ ) —O— (CH ₂ ) ₂ —O—
R ¹⁷ : H— (CF ₂ ) ₆ — (CH ₂ ) —O— (CH ₂ ) ₂ —O—
_{^{R 18: H- (CF 2)}} 4 - (CH 2) -O- (CH 2) 2 -O-

X ^1a , X ^2a and X ^3a preferably each represent —NH— or —O—, and more preferably —NH—. m1a, m2a and m3a are each preferably 2.

Next, the compound represented by formula (Ib) will be described.
The alkyl group having a CF ₃ group or a CF ₂ H group at the terminal represented by Rf ¹ , Rf ² and Rf ³ may be linear or branched, and preferably has 4 to 4 carbon atoms. It is 20, More preferably, it is C4-C16, Most preferably, it is 6-16. It may have a CF ₃ group or CF ₂ H substituents other than groups. The alkyl group having a CF ₃ group or a CF ₂ H group at the terminal is an alkyl group in which some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of the hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. Examples of alkyl groups having a CF ₃ group or a CF ₂ H group at the ends represented by Rf ¹ , Rf ² and Rf ³ are shown below.

Rf ¹ : n-C ₈ F ₁₇ −
_{^{Rf 2: n-C 6 F}} 13 -
_{^{Rf 3: n-C 4 F}} 9 -
_{^{Rf 4: n-C 8 F}} 17 - (CH 2) 2 -
_{^{Rf 5: n-C 6 F}} 13 - (CH 2) 2 -
_{^{Rf 6: n-C 4 F}} 9 - (CH 2) 2 -
_{^{Rf 7: H- (CF 2)}} 8 -
_{^{Rf 8: H- (CF 2)}} 6 -
_{^{Rf 9: H- (CF 2)}} 4 -
_{^{Rf 10: H- (CF 2)}} 8 - (CH 2) -
_{^{Rf 11: H- (CF 2)}} 6 - (CH 2) -
_{^{Rf 12: H- (CF 2)}} 4 - (CH 2) -

Y ¹ , Y ² and Y ³ each preferably represent a group obtained by combining at least two divalent linking groups selected from an alkylene group, —NH—, —O—, —S—, and a group thereof. Particularly preferably a group in which at least two divalent linking groups selected from an alkylene group, —NH—, —O—, and a group thereof are combined, and more preferably —NH—, —O— or —NH (CH ₂ ) _r —O— (r represents an integer of 1 to 8, most preferably 3).

Next, the compound represented by formula (II) will be described.
In the formula (II), each of the substituents represented by R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ is represented by R ¹ , R ² , and R ³ in the general formula (I). It is synonymous with a substituent, The preferable range is also the same. m preferably represents an integer of 1 to 3, particularly preferably 2 or 3. At least one of R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ represents a substituent containing fluorine. Of R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ , two or three are preferably substituents, three are preferably substituents, and three are substituents containing a fluorine atom. Preferably there is.

  Among the compounds represented by the general formula (II), a compound represented by the following general formula (IIa) is particularly preferable.

In the formula, Rf ^1a , Rf ^2a and Rf ^3a each independently represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal, Y ^1a , Y ^2a and Y ^3a are each independently an alkylene group,- CO -, - NH -, - O -, - S -, - representing the and combining at least two groups a divalent linking group selected from these groups - SO _2.

Examples of the alkyl group having a CF ₃ group or a CF ₂ H group at the terminals represented by Rf ^1a , Rf ^2a and Rf ^3a include the terminal represented by Rf ¹ , Rf ² and Rf ³ in the general formula (Ib). It has the same meaning as alkyl group having a CF ₃ group or CF ₂ H group, and the preferable ranges thereof are also the same. Y ^1a , Y ^2a and Y ^3a are those in the general formula (Ib). Y ^1, have the same meanings as Y ² and Y ^3, and the preferable ranges thereof are also the same. More preferably, it is a group obtained by combining at least two divalent linking groups selected from an alkylene group, —O—, and a group thereof.

Finally, the compound represented by formula (III) will be described.
The substituents represented by R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ have the same meaning as the substituents represented by R ¹ , R ² and R ³ in the general formula (I). The preferred range is also the same. At least one of R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ represents a substituent having a fluorine atom. All preferably represent substituents having a fluorine atom.

  Among the compounds represented by the general formula (III), compounds represented by the following general formula (IIIa) are particularly preferable.

In the formula, Rf ^11a , Rf ^22a , Rf ^33a , Rf ^44a , Rf ^55a and Rf ^66a each independently represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal, and Y ^11a , Y ^22a , Y ^33a, Y ^44a, Y ^55a and Y ^66a each independently, an alkylene group, -CO -, - NH -, - O -, - S -, - SO 2 - and a divalent linking of selected from these groups A group in which at least two groups are combined is represented.

Examples of the alkyl group having a CF ₃ group or a CF ₂ H group at the ends represented by Rf ^11a , Rf ^22a , Rf ^33a , Rf ^44a , Rf ^55a and Rf ^66a are Rf ¹ , Rf in the general formula (Ib). the terminal which is represented by ² and Rf ³ has the same meaning as alkyl group having a CF ₃ group or CF ₂ H group, and the preferable ranges thereof are also the same. Y ^11a , Y ^22a , Y ^33a , Y ^44a , Y ^55a and Y ^66a are the same as those in the general formula (Ib). Y ^1, have the same meanings as Y ² and Y ^3, and the preferable ranges thereof are also the same. More preferably, it is a group obtained by combining at least two divalent linking groups selected from an alkylene group, —O—, and a group thereof.

  Specific examples of the compound represented by the general formula (I), (II) or (III) are shown below, but the compound used in the present invention is not limited thereto. In the following specific examples, no. S-1 to S39 represent the general formula (I), No. S-40 to 50 are general formula (II), No. S-51 to 59 are examples of the compound represented by the general formula (III).

The addition amount of the compounds represented by the general formulas (I) to (III) is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, based on the amount of the liquid crystal compound. 1-5 mass% is especially preferable. In addition, the compounds represented by the general formulas (I) to (III) may be used alone or in combination of two or more.
The compound having a 1,3,5-triazine ring represented by the general formula (I) can be easily synthesized by the method described in JP-A-2002-20363, and the general formulas (II) and (II) The compound represented by III) can be easily synthesized by combining general alkyl group alkylation reaction, esterification reaction, etherification reaction and the like. In addition, compounds described in Japanese Patent Application No. 2003-331269 can be used, and methods for synthesizing these compounds are also described in the specification.

[Alignment layer]
In the present invention, the polymer layer is used as the alignment layer. In the first aspect of the present invention, from the viewpoint of the alignment characteristics of the liquid crystal in forming the optically anisotropic layer, the polymer layer formed by coating and drying using a solution having a solvent composition of 20% or more of water is aligned. Used as a layer. The alignment layer is chemically bonded to the optically anisotropic layer. Also in the second aspect of the present invention, an alignment layer formed by applying and drying a solution composed of a solvent composition having a water content of 20% or more is used from the viewpoint of the alignment characteristics of the liquid crystal in forming the optically anisotropic layer. When the alignment layer is chemically bonded to the optically anisotropic layer, the adhesion is improved. For example, when washing treatment, saponification treatment or the like is performed, peeling or the like does not occur, which is preferable.
The polymer layer is preferably formed from a polymer solution having a reactive group and having a solvent composition of 20% or more of water. The water of the polymer solution is preferably 40% or more, and more preferably 60% or more. Preferred examples of the polymer include a polyvinyl alcohol derivative, a poly (meth) acrylate derivative, or a polysaccharide that is soluble in a solvent containing 20% or more of water. The reactive group of the polymer is not particularly limited as long as it is a group capable of chemically bonding to a component in the optically anisotropic layer, preferably a liquid crystal compound. The reactive group of the polymer is preferably capable of addition polymerization (including ring-opening polymerization) reaction, and can be chemically bonded to the optically anisotropic layer by addition polymerization reaction or ring-opening polymerization reaction. Preferably there is. Preferred examples of the reactive group possessed by the polymer include a reactive group having an ethylene group such as an acryloyl group, a methacryloyl group, and a vinyl group, a cyclic ether group such as an alicyclic epoxy group, a cyclic sulfide, and a cyclic imine. These reactive groups are included. More preferred examples include acryloyl group, methacryloyl group, vinyl group, alicyclic epoxy group and the like. When a polymer layer is formed using such a polymer having a reactive group, a composition containing a liquid crystal compound having a reactive group is applied to the surface of the polymer layer and dried to align the liquid crystal molecules in a desired orientation. When light and / or heat is applied to advance the reaction of the liquid crystalline molecules after the state is changed, not only the reaction proceeds between the reactive groups of the liquid crystalline molecules, but also the polymers in the polymer layer While the reaction proceeds between the reactive groups, the reaction between the reactive group of the polymer and the reactive group of the liquid crystal molecule also proceeds at the interface between the polymer layer and the optically anisotropic layer. As a result, the strength of the polymer layer is improved and the adhesion between the polymer layer and the optically anisotropic layer is also improved.

  The introduction amount of the reactive group in the polymer is preferably 0.3 or less, particularly preferably 0.2 or less in terms of the weight ratio of the reactive group introduction to the total weight of the polymer. Furthermore, a surface treatment may be performed to impart an alignment function to the polymer layer. As a method of imparting an orientation function, a method of chemically or physically treating is known, and a method of performing a rubbing treatment is generally employed. The rubbing treatment is performed by rubbing the surface of the alignment layer several times in a certain direction with paper or cloth. In addition, methods for imparting an alignment function by applying an electric field, applying a magnetic field, or irradiating light are known, but it is particularly preferable to perform a rubbing treatment. The thickness of the polymer layer (alignment layer) is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

  The polymer layer is formed by coating by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method or an extrusion coating method (US Pat. No. 2,681,294). can do. Two or more layers may be applied simultaneously. The method of simultaneous application is described in US Pat. Nos. 2,761791, 2,941,898, 3,508,947, and 3,526,528 and Yuji Harasaki, Coating Engineering, page 253, Asakura Shoten (1973).

  The optically anisotropic layer can be transferred by aligning the liquid crystal compound on the temporary alignment layer, fixing the alignment, and using a pressure sensitive adhesive on the transparent support, but from the viewpoint of productivity. It is preferable to form a functional film directly without transfer.

[Transparent support]
As the transparent support for the optically anisotropic layer, it is preferable to use a polymer film having a light transmittance of 80% or more. The thickness of the transparent support is preferably 10 to 500 μm, more preferably 20 to 200 μm, and more preferably 35 to 110 μm.

  The glass transition temperature (Tg) of the transparent support is appropriately determined according to the purpose of use. The glass transition temperature of the resin is preferably 70 ° C. or higher, more preferably 75 ° C. to 200 ° C., and particularly preferably 80 ° C. to 180 ° C. When a resin in this range is employed, heat resistance and molding processability are highly balanced, which is preferable.

  The Re of the transparent support is preferably adjusted to a range of −200 to 100 nm, and Rth is preferably adjusted to a range of −100 to 100 nm. Re is preferably −50 to 30 nm, more preferably −30 to 20 nm. The birefringence (Δn: nx−ny) of the cellulose ester film is preferably in the range of 0 to 0.02. Further, when the thickness of the cellulose ester film is dnm, Rth / d is preferably in the range of 0 to 0.04. In the present specification, negative Re means that the in-plane slow axis of the transparent support is in the TD direction, and negative Rth means that the refractive index in the thickness direction is larger than the in-plane average refractive index.

  Examples of the polymer constituting the transparent support include cellulose ester (eg, cellulose acetate, cellulose propionate, cellulose butyrate), polyolefin (eg, norbornene-based polymer), poly (meth) acrylic acid ester (eg, poly Methyl methacrylate), polycarbonate, polyester and polysulfone, norbornene-based polymers. From the viewpoint of low birefringence, cellulose esters and norbornene-based polymers are preferred, and as commercially available norbornene-based polymers, Arton (manufactured by JSR Corporation), Zeonex, Zeonore (above, Nippon Zeon Corporation) and the like are used. Can do.

  In particular, when used as a protective film for a polarizing plate, cellulose ester is preferable, and cellulose lower fatty acid ester is more preferable. Lower fatty acid means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used. Among the lower fatty acid esters of cellulose, cellulose acetate is more preferable. The acyl group substitution degree of the cellulose ester is preferably 2.50 to 3.00, more preferably 2.75 to 2.95, and even more preferably 2.80 to 2.90.

  The viscosity average polymerization degree (DP) of the cellulose ester is preferably 250 or more, and more preferably 290 or more. In addition, the cellulose ester preferably has a narrow molecular weight distribution of Mm / Mn (Mm is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. The value of Mm / Mn is preferably 1.0 to 5.0, more preferably 1.3 to 3.0, and more preferably 1.4 to 2.0.

  In the cellulose ester, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted but the degree of substitution at the 6-position tends to be small. In the present invention, the 6-position substitution degree of the cellulose ester is preferably about the same as or higher than the 2-position and 3-position. The ratio of the 6-position substitution degree to the total of the 2-position, 3-position and 6-position substitution degrees is preferably 30 to 40%. The ratio of the 6-position substitution degree is preferably 31% or more, particularly preferably 32% or more. The substitution degree at the 6-position is preferably 0.88 or more. The 6-position of cellulose may be substituted with an acyl group having 3 or more carbon atoms (eg, propionyl, butyryl, valeroyl, benzoyl, acryloyl) in addition to acetyl. The degree of substitution at each position can be measured by NMR. Cellulose esters having a high degree of substitution at the 6-position are described in Synthesis Example 1 described in Paragraph Nos. 0043 to 0044, Synthesis Example 2 described in Paragraph Nos. 0048 to 0049, and Paragraph Nos. 0051 to 0052. It can synthesize | combine with reference to the synthesis example 3 of these.

  A plasticizer can be added to the cellulose ester film in order to improve mechanical properties or increase the drying speed. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP), tricresyl phosphate (TCP), and biphenyl diphenyl phosphate. Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred. The addition amount of the plasticizer is preferably 0.1 to 25% by weight of the amount of cellulose ester, more preferably 1 to 20% by weight, and still more preferably 3 to 15% by weight.

  A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the cellulose ester film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by weight of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by weight. When the addition amount is less than 0.01% by weight, the effect of the deterioration preventing agent is hardly recognized. When the added amount exceeds 1% by weight, bleed-out (bleeding) of the deterioration preventing agent to the film surface may be observed. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA). Furthermore, a very small amount of dye may be added to prevent light piping. From the viewpoint of transmittance, it is preferable to adjust the type and amount so that the transmittance of light having a wavelength of 420 nm is 50% or more. The added amount of the dye is preferably 0.01 ppm to 1 ppm.

  In order to control the Re retardation value and the Rth retardation value, a retardation control agent can be added to the cellulose ester film. The retardation control agent is preferably used in the range of 0.01 to 20 parts by mass, more preferably 0.05 to 15 parts by mass, with respect to 100 parts by mass of the cellulose ester. More preferably, it is used in the range of 1 to 10 parts by mass. Two or more retardation control agents may be used in combination. The retardation control agent is described in the pamphlets of International Publication No. WO01 / 88574 and International Publication No. WO00 / 2619, and Japanese Unexamined Patent Publication Nos. 2000-1111914 and 2000-275434.

  The cellulose ester film can be produced by a solvent cast method using a solution containing cellulose ester and other components as a dope. The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 10 to 40% by weight. The solid content is more preferably 18 to 35% by weight. Two or more dopes can be cast. The surface of the drum or band is preferably finished in a mirror state. The casting and drying methods in the solvent casting method are described in U.S. Pat. No. 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, No. 60-203430, and No. 62-115035.

  The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less. After casting, it is preferable to dry it by applying air for 2 seconds or more. Then, the method can be employed in which the obtained film is peeled off from the drum or band and further dried with high-temperature air at different temperatures of 100 to 160 ° C. to evaporate the residual solvent (described in Japanese Patent Publication No. 5-17844). . According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting. When casting a plurality of cellulose ester solutions, a solution is prepared by casting a solution containing cellulose ester from a plurality of casting openings provided at intervals in the traveling direction of the support, and laminating them. (Japanese Patent Laid-Open Nos. 61-158414, 1-122419, and 11-198285). A film can also be produced by casting a cellulose ester solution from two casting ports (Japanese Patent Publication Nos. 60-27562, 61-94724, 61-947245, 61-104413, No. 61-158413 and JP-A-6-134933). Employs a method of casting a cellulose ester film (described in JP-A-56-162617) by wrapping a flow of a high-viscosity cellulose ester solution with a low-viscosity cellulose ester solution and simultaneously extruding the high-viscosity and low-viscosity cellulose ester solutions. May be.

  The retardation of the cellulose ester film can be further adjusted by a stretching treatment. The draw ratio is preferably in the range of 3 to 100%. Tenter stretching is preferred. In order to control the slow axis with high accuracy, it is preferable to make the difference between the left and right tenter clip speeds and the separation timing as small as possible. The stretching process is described on page 37, line 8 to page 38, line 8 of WO 01/88574.

  The cellulose ester film can be subjected to a surface treatment. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. From the viewpoint of maintaining the flatness of the film, the temperature of the cellulose ester film in the surface treatment is preferably Tg (glass transition temperature) or lower, specifically 150 ° C. or lower.

  The thickness of the cellulose ester film can be adjusted by lip flow rate and line speed, or stretching or compression when it is produced by film formation. Since the moisture permeability varies depending on the main material to be used, it is possible to obtain a preferable moisture permeability range as a protective film for the polarizing plate by adjusting the thickness. Moreover, the free volume of the said cellulose-ester film can be adjusted with drying temperature and time, when producing by film forming. Also in this case, since the moisture permeability varies depending on the main material used, it is possible to make the moisture permeability range preferable as a protective film by adjusting the free volume. The hydrophilicity / hydrophobicity of the cellulose ester film can be adjusted by an additive. Moisture permeability is increased by adding a hydrophilic additive in the free volume, and conversely, moisture permeability can be lowered by adding a hydrophobic additive. Thus, by adjusting the moisture permeability of the cellulose ester film by various methods, it is possible to obtain a range of moisture permeability preferable as a protective film for the polarizing plate, and the support for the optically anisotropic layer is protected for the polarizing plate. A polarizing plate that can also serve as a film and has optical compensation ability can be manufactured at low cost with high productivity.

[Polarizer]
The polarizing plate used for the liquid crystal display device of the present invention comprises a polarizing film and a pair of protective films that sandwich the polarizing film. Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film. The kind of protective film is not particularly limited, and cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose propionate, polycarbonate, polyolefin, polystyrene, polyester, and the like can be used. The transparent protective film is usually supplied in a roll form, and it is preferable that the transparent 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. 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.

The polarizing film and the protective film may be bonded together with an aqueous adhesive. The adhesive solvent in the water-based adhesive is dried by diffusing in the protective film. The higher the moisture permeability of the protective film, the faster the drying and the higher the productivity. However, if the protective film is too high, the moisture will enter the polarizing film due to the usage environment (high humidity) of the liquid crystal display device. The performance drops. The moisture permeability of the optical compensation sheet is determined by the thickness, free volume, hydrophilicity / hydrophobicity, etc. of the polymer film (and polymerizable liquid crystal compound). The moisture permeability of the protective film for the polarizing plate is preferably in the range of 100 to 1000 (g / m ² ) / 24 hrs, and more preferably in the range of 300 to 700 (g / m ² ) / 24 hrs.

  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 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.

  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 having an average particle diameter of 0.5 to 20 μm, such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide. One kind or two or more kinds of fine particles, cross-linked or non-cross-linked 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.

  The optical properties and durability (storability in the short term and long term) of the polarizing plate comprising the protective film, the polarizing film and the transparent support relating to the present invention are commercially available super high contrast products (for example, manufactured by Sanritz Corporation). HLC2-5618 etc.) is preferable. Specifically, the visible light transmittance is 42.5% or more, and the degree of polarization √ ({(Tp−Tc) / (Tp + Tc)} ≧ 0.9995 (where Tp is parallel transmittance and Tc is orthogonal transmittance) ), And the change rate of the light transmittance before and after being left for 500 hours in an atmosphere of 60 ° C. and humidity of 90% RH for 500 hours and 80 ° C. in a dry atmosphere is 3% or less based on the absolute value, Further, it is preferably 1% or less, and the rate of change in polarization degree is preferably 1% or less, more preferably 0.1% or less based on the absolute value.

  The display mode of the liquid crystal display device used in the present invention is not particularly limited, but the VA mode is preferably used. Note that the liquid crystal display device used in the present invention is effective not only in the display mode but also in an aspect applied to the STN mode, the TN mode, and the OCB mode.

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. However, Examples 1-1 to 1-7 are reference examples.

(Preparation of transparent support S-1)
A commercial cellulose acetate film, Fujitac TD80UF (Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 50 nm) was used as the transparent support S-1.

(Preparation of transparent support S-2)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

  The obtained inner layer dope and outer layer dope were cast on a drum cooled to 0 ° C. using a three-layer co-casting die. The film having a residual solvent amount of 70% by mass is peeled off from the drum, both ends are fixed with a pin tenter and dried at 80 ° C. while transporting at a draw ratio of 110% in the transport direction, and the residual solvent amount is 10%. Then, it was dried at 110 ° C. Thereafter, a cellulose acetate film (outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) having a residual solvent of 0.3% by mass produced by drying at 140 ° C. for 30 minutes was used as the transparent support S-2. The optical properties of the obtained film were Re = 8 nm and Rth = 82 nm.

(Preparation of transparent support S-3)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution. The UV agent described in “Known Technology No. 157” (issued by Aztec Corporation, 2003) was used.

  Then, it filtered with the filter paper (Toyo Filter Paper Co., Ltd. product # 63) with an absolute filtration accuracy of 0.01 mm, and further filtered with the filter paper (FH025 made by Paul Co., Ltd.) with an absolute filtration accuracy of 2.5 μm. The above-mentioned dope was heated to 35 ° C., and casted through a Giesser onto a mirror surface stainless steel drum having a diameter of 3 m set at −15 ° C. The Gieseer used was similar to that described in Japanese Patent Application Laid-Open No. 11-314233. The casting speed was 100 m / min and the casting width was 250 cm. After the residual solvent was peeled off at 200% by mass, the film was dried at 130 ° C. and wound up when the residual solvent became 1% by mass or less to prepare a cellulose acylate film. The obtained film was trimmed at both ends by 3 cm, and then a knurling having a height of 100 μm was imparted to a portion 2 to 10 mm from both ends, and wound into a 3000 m roll. The biaxially stretched film was used as a transparent support S-3 (Re = 10 nm, Rth = 40 nm).

(Preparation of coating liquid AL-1 for alignment layer)
The following composition was prepared, filtered through a polypropylene filter having a pore size of 30 μm, and used as an alignment layer coating liquid AL-1.

(Preparation of coating liquid AL-2 for alignment layer)
The following composition was prepared, filtered through a polypropylene filter having a pore size of 30 μm, and used as an alignment layer coating liquid AL-2.

(Preparation of coating liquid LC-1 for optically anisotropic layer)
After preparing the following composition, it filtered with the polypropylene filter with the hole diameter of 0.2 micrometer, and used as coating liquid LC-1 for optical anisotropic layers.

LC-1-1:
Angew. Makromol. Chem. It was synthesized according to the method described in Journal, Vol. 183, p. 45 (1990).
LC-1-2:
It was synthesized by condensing 4- (6-acryloyloxyhexyloxy) benzoic acid synthesized by the method described in EP1174411B1 and 4-propylcyclohexylphenol (manufactured by Kanto Chemical).
LC-1-3:
4- (6-acryloyloxyhexyloxy) benzoic acid synthesized by the method described in EP1174411B1 and 4-hydroxy-4 ′-(2-methylbutyl) biphenyl synthesized by the method described in WO / 2001040154A1 are condensed. And synthesized.
LC-1-4:
It was synthesized by the method described in EP1389199A1.
LC-1-5:
Hydroxypropyl acrylate (manufactured by Aldrich) was mesylated, reacted with 4-propylcyclohexylphenol (manufactured by Kanto Chemical), and then hydrogen sulfide was added to synthesize.
LC-1-6:
4-Propylcyclohexylphenol (manufactured by Kanto Chemical Co., Ltd.) was triflated to give a biphenyl compound by Suzuki coupling reaction with phenylboronic acid. Furthermore, after acylating the 4′-position of biphenyl with isobutyric chloride and aluminum chloride, the carbon at the α-position of the carbonyl was brominated with bromine and then converted into a hydroxyl group with an alkali.

(Preparation of coating liquid LC-2 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-2 for an optically anisotropic layer.

(Preparation of coating liquid LC-3 for optical anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-3 for an optically anisotropic layer.

(Preparation of coating liquid LC-4 for optical anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-4 for an optically anisotropic layer.

  LC-1-1, LC-1-2, LC-1-3, LC-1-4, LC-1-5 and LC-1-6 were synthesized in the same manner as described above.

(Preparation of coating liquid LC-5 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-5 for an optically anisotropic layer.

(Preparation of coating liquid LC-6 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-6 for an optically anisotropic layer.

(Preparation of coating liquid LC-7 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-7 for optical anisotropic layer.

(Preparation of coating liquid LC-8 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-8 for an optically anisotropic layer.

(Preparation of coating liquid LC-9 for optically anisotropic layer)
After the following composition was prepared, it was filtered through a polypropylene filter having a pore size of 0.2 μm and used as a coating liquid LC-9 for optical anisotropic layer.

(Single-side saponification treatment of cellulose ester film)
The cellulose ester film was passed through a dielectric heating roll having a temperature of 60 ° C. and the film surface temperature was raised to 40 ° C., and then an alkali solution having the composition shown below was applied at 14 ml / m ² using a bar coater. Then, after retaining for 10 seconds under a steam far infrared heater (manufactured by Noritake Co., Ltd.) heated to 110 ° C., 3 ml / m ^{2 of} pure water was applied using the same bar coater. The film temperature at this time was 40 degreeC. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then the sample was retained in a drying zone at 70 ° C. for 2 seconds and dried.

[Example 1-1]
One side of the transparent support S-1 was saponified using the above-mentioned one-side saponification method, and then the coating liquid AL-1 for alignment layer was applied thereon with a # 14 wire bar coater, An alignment layer having a thickness of 1.0 μm was formed by drying with warm air for 60 seconds and further with warm air at 90 ° C. for 150 seconds. Subsequently, after rubbing the formed alignment layer with respect to the slow axis direction of the transparent support, the optically anisotropic layer coating liquid LC-1 was applied thereon with a # 3 wire bar coater and 60 ° C. An optically anisotropic layer having a uniform liquid crystal phase was formed by heat drying for 1 minute. Further, immediately after aging, the transmission axis of the polarizing plate is made to be the slow axis direction of the transparent support using POLUV-1 in a nitrogen atmosphere with an oxygen concentration of 0.3% or less with respect to the optically anisotropic layer. Irradiated with polarized UV (illuminance 200 mW / cm ² , irradiation amount 200 mJ / cm ² ), an optical compensation sheet of Example 1-1 was produced. The optically anisotropic layer showed no liquid crystal phase even when heated after fixing. The thickness of the optically anisotropic layer was 1.3 μm.
The following evaluation was performed on the obtained optical compensation sheet.

Adhesion test (dry adhesion)
The presence or absence of peeling was visually observed by a cross-cut method, and the following three-stage evaluation was performed.
◯: No peeling was observed
Δ: 10% or more peeling was observed
X: 50% peeled off

(Wet adhesion)
A 24 × 36 mm sample was immersed in hot water of 60 ° C. for 5 minutes, and the presence or absence of peeling was visually observed, and the following three-stage evaluation was performed.
◯: No peeling was observed
Δ: 10% or more peeling was observed
X: 50% peeled off

(Phase difference measurement)
Retardation Re (40) and Re (−40) when a sample is tilted ± 40 degrees with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) and front retardation Re at 589 nm and the slow axis as the rotation axis. It was measured.

[Example 1-2]
The optically anisotropic sheet was prepared in the same manner as in Example 1-1 except that the optically anisotropic layer coating liquid LC-1 in Example 1-1 was changed to the optically anisotropic layer coating liquid LC-2.

[Example 1-3]
The optically anisotropic layer coating liquid LC-1 in Example 1-1 was changed to the optically anisotropic layer coating liquid LC-3, and the rest was carried out in the same manner as in Example 1-1 to produce an optical compensation sheet.

[Example 1-4]
The transparent support S-1 in Example 1-1 was changed to the transparent support S-2, and the rest was performed in the same manner as in Example 1-1 to produce an optical compensation sheet.
[Example 1-5]
The transparent support S-1 in Example 1-1 was changed to the transparent support S-3, and the rest was performed in the same manner as in Example 1-1 to produce an optical compensation sheet.
[Comparative Example 1]
The alignment layer coating liquid AL-1 in Example 1-1 was changed to the alignment layer coating liquid AL-2, and the rest was carried out in the same manner as in Example 1-1 to produce an optical compensation sheet.

The adhesion evaluation results of Examples 1-1 to 1-5 and Comparative Example 1-1 are shown in Table 1-1. Optical anisotropy of Examples 1-1 to 1-3 and 1-5 and Comparative Example 1-1 The phase difference measurement results of the layers are shown in Table 1-2.

  In addition, for the optical compensation films of Example 1-1 and Examples 1-3 to 1-5, it is confirmed that the rod-shaped molecules are oriented at less than 3 degrees with respect to the transparent substrate by observation with a cross-sectional section transmission electron microscope. confirmed. Regarding the optical compensation film of Example 1-2, it was confirmed by observing a cross-sectional slice with an optical microscope that the discotic molecules were oriented at less than 3 degrees with respect to the transparent substrate.

[Example 1-6]
(Preparation of polarizing plate with optical compensation sheet)
Laminated body of optical compensation sheet and optical anisotropic layer of Examples 1-1 to 1-5 and Comparative Example 1-1 of the present invention and commercially available Fujitac TD80UF (Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 50 nm) was immersed in a 1.5 mol / L aqueous sodium hydroxide solution at 55 ° C for 2 minutes. Subsequently, it was washed in a water bath at room temperature and neutralized at 30 ° C. with 0.05 mol / L sulfuric acid. This was washed again in a room temperature water bath and further dried with hot air at 100 ° C. Thereafter, washing with water and neutralization treatment were performed, and the two saponified films were attached to both surfaces of the polarizing film with a roll-to-roll using a polyvinyl alcohol adhesive as a protective film for the polarizing plate. A body-type polarizing plate was produced. All of the examples of the first aspect of the present invention were excellent in productivity, and the optically anisotropic layer exhibited a good surface shape. The comparative example not only has insufficient adhesion, but also caused problems such as a decrease in productivity due to the saponification treatment on one side before the alignment layer coating and contamination of the saponification bath during processing of the polarizing plate. .

[Example 1-7]
(Production of VA-LCD liquid crystal display device)
Example 1 which is an example of the first embodiment of the present invention, peels off the upper and lower polarizing plates of a commercially available VA-LCD (SyncMaster 173P, manufactured by Samsung Electronics Co., Ltd.), on the upper side, with a normal polarizing plate on the upper side. The polarizing plate with an optical compensation sheet of Examples 1-1 and 1-2, which is an example of the first aspect of the present invention prepared in -6, is used so that the optically anisotropic layer becomes the liquid crystal cell substrate glass surface. The liquid crystal display device of the present invention was produced by pasting with an adhesive. FIG. 5 shows a schematic cross-sectional view of the manufactured liquid crystal display device together with the angular relationship of the optical axes of the respective layers. In FIG. 5, 41 is a polarizing layer, 42 is a transparent support, 43 is an alignment layer, 44 is an optically anisotropic layer (41 to 44 constitute the optical compensation sheet of the first aspect of the present invention), 45 is A polarizing plate protective film, 46 is a glass substrate for a liquid crystal cell, 47 is a liquid crystal cell, and 48 is an adhesive layer. Further, the arrow in the polarizing layer 41 indicates the direction of the absorption axis, the arrow in the optically anisotropic layer 44 or its support 44 and the protective film 45 indicates the direction of the slow axis, and the circle indicates the direction of the arrow relative to the paper surface. Indicates the line direction.

(Evaluation of VA-LCD liquid crystal display device)
The viewing angle characteristics of the manufactured liquid crystal display device were measured with a viewing angle measuring device (EZ Contrast 160D, manufactured by ELDIM). Furthermore, it evaluated also visually about 45 degree | times diagonally especially. FIG. 6 shows the contrast characteristics of Example 1-7 by EZ Contrast, and Table 1-3 shows the visual evaluation results.

[Example 2-1]
One side of the transparent support S-1 was saponified using the above-mentioned one-side saponification method, and then the coating liquid AL-1 for alignment layer was applied thereon with a # 14 wire bar coater, An alignment layer having a thickness of 1.0 μm was formed by drying with warm air for 60 seconds and further with warm air at 90 ° C. for 150 seconds. Subsequently, the formed alignment layer was rubbed with respect to the slow axis direction of the transparent support, and then the optical anisotropic layer coating liquid LC-4 was applied thereon with a # 3 wire bar coater, at 60 ° C. An optically anisotropic layer having a uniform liquid crystal phase was formed by heat drying for 1 minute. Further, immediately after aging, the transmission axis of the polarizing plate is made to be the slow axis direction of the transparent support using POLUV-1 in a nitrogen atmosphere with an oxygen concentration of 0.3% or less with respect to the optically anisotropic layer. The optical compensation sheet of Example 2-1 was produced by irradiation with polarized UV (illuminance 200 mW / cm ² , irradiation amount 200 mJ / cm ² ). The optically anisotropic layer showed no liquid crystal phase even when heated after fixing. The thickness of the optically anisotropic layer was 1.3 μm.
The following evaluation was performed on the obtained optical compensation sheet.

(Surface evaluation)
The optical compensation film produced in Example 2-1 was put between a pair of polarizing plates arranged in crossed Nicols, and the surface condition was visually evaluated by applying illumination from below. Evaluation criteria are
A: Unevenness and defects are hardly seen in the test product.
○: A portion where unevenness or defect occurs in the test product is observed.
X: Many irregularities and defects are observed in the test product. age,
X is a level not suitable for manufacturing. Furthermore, based on JIS K7136: 2000, the haze of the optical compensation film obtained using the haze meter ("NDH2000", Nippon Denshoku Industries Co., Ltd. product) was measured.
Table 1 shows the surface evaluation results and the measured values of haze.
(Phase difference measurement)
Retardation Re (40) and Re (−40) when a sample is tilted ± 40 degrees with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) and front retardation Re at 589 nm and the slow axis as the rotation axis. It was measured

[Example 2-2]
An optical compensation sheet was produced in the same manner as in Example 2-1, except that the optically anisotropic layer coating liquid LC-4 in Example 2-1 was replaced with the optically anisotropic layer coating liquid LC-5.

[Example 2-3]
An optical compensation sheet was produced in the same manner as in Example 2-1, except that the optical anisotropic layer coating liquid LC-4 in Example 2-1 was replaced with the optical anisotropic layer coating liquid LC-6.

[Comparative Example 2-1]
An optical compensation sheet was produced in the same manner as in Example 2-1, except that the optical anisotropic layer coating liquid LC-4 in Example 2-1 was replaced with the optical anisotropic layer coating liquid LC-7.
[Comparative Example 2-2]
An optical compensation sheet was produced in the same manner as in Example 2-1, except that the optical anisotropic layer coating liquid LC-4 in Example 2-1 was replaced with the optical anisotropic layer coating liquid LC-8.
[Comparative Example 2-3]
An optical compensation sheet was produced in the same manner as in Example 2-1, except that the optical anisotropic layer coating liquid LC-4 in Example 2-1 was replaced with the optical anisotropic layer coating liquid LC-9.

  Regarding Examples 2-2 to 2-3 and Comparative Examples 2-1 to 2-3, the surface shape was evaluated in the same manner as in Example 2-1, and the retardation of the optically anisotropic layer was measured. The surface evaluation results are shown in Table 2-1, and the phase difference measurement results are shown in Table 2-2.

In addition, when the optical compensation film was produced like Example 2-1 to 2-3 except having changed horizontal alignment agent S-22 into S-40 or S-56, the same planar improvement effect was confirmed. We were able to.
Moreover, about the optical compensation film of Example 2-1 and Example 2-3, it confirmed that the rod-shaped molecule | numerator orientated at less than 3 degree | times with respect to the transparent substrate by cross-sectional section transmission electron microscope observation. In addition, regarding the optical compensation film of Example 2-2, it was confirmed that the discotic molecules were oriented at less than 3 degrees with respect to the transparent substrate by observing the cross-section with an optical microscope.

[Example 2-4]
(Preparation of polarizing plate with optical compensation sheet)
Examples 2-1 to 2-3 of the present invention Each of the optical compensation sheets of Comparative Examples 2-1 to 2-3, and commercially available Fujitac TD80UF (Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 50 nm) Was immersed in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. for 2 minutes. Subsequently, it was washed in a water bath at room temperature and neutralized at 30 ° C. with 0.05 mol / L sulfuric acid. This was washed again in a room temperature water bath and further dried with hot air at 100 ° C. Thereafter, washing with water and neutralization treatment were performed, and the two saponified films were attached to both surfaces of the polarizing film with a roll-to-roll using a polyvinyl alcohol adhesive as a protective film for the polarizing plate. A body-type polarizing plate was produced. The examples of the second aspect of the present invention were all excellent in productivity, and the optically anisotropic layer showed a good surface shape.

[Example 2-5]
(Production of VA-LCD liquid crystal display device)
The upper and lower polarizing plates of a commercially available VA-LCD (SyncMaster 173P, manufactured by Samsung Electronics Co., Ltd.) are peeled off, the normal polarizing plate is used on the upper side, and the polarizing plate with the optical compensation sheet of the present invention is used on the lower side. The liquid crystal display device of the present invention was produced by pasting with a pressure-sensitive adhesive such that the layer was on the liquid crystal cell substrate glass surface. FIG. 5 shows a schematic cross-sectional view of the manufactured liquid crystal display device together with the angular relationship of the optical axes of the respective layers. In FIG. 5, 41 is a polarizing layer, 42 is a transparent support, 43 is an alignment layer, 44 is an optically anisotropic layer (the optical compensation sheet of the present invention is composed of 41 to 44), 45 is a polarizing plate protective film, 46 is a glass substrate for a liquid crystal cell, 47 is a liquid crystal cell, and 48 is an adhesive layer. Further, the arrow in the polarizing layer 41 indicates the direction of the absorption axis, the arrow in the optically anisotropic layer 44 or its support 44 and the protective film 45 indicates the direction of the slow axis, and the circle indicates the direction of the arrow relative to the paper surface. Indicates the line direction.

(Evaluation of VA-LCD liquid crystal display device)
The viewing angle characteristics of the manufactured liquid crystal display device were measured with a viewing angle measuring device (EZ Contrast 160D, manufactured by ELDIM). Furthermore, it evaluated also visually about 45 degree | times diagonally especially. FIG. 7 shows the contrast characteristics of Example 2-5 by EZ Contrast, and Table 2-3 shows the visual evaluation results.

It is a schematic sectional drawing of an example of the optical compensation sheet | seat of the 1st aspect of this invention. It is a schematic sectional drawing of an example of the optical compensation sheet | seat of the 2nd aspect of this invention. It is a schematic sectional drawing of the example of the polarizing plate of this invention. It is a schematic sectional drawing of an example of the liquid crystal display device of this invention. It is the schematic sectional drawing which showed the layer structure of the liquid crystal display device produced in Example 1-7 and Example 2-5 with the direction of the optical axis in a layer. It is a figure which shows the contrast characteristic of the liquid crystal display device produced in Example 1-7. It is a figure which shows the contrast characteristic of the liquid crystal display device produced in Example 2-5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Transparent support 12, 12 'Optically anisotropic layer 13, 13' which consists of a liquid crystal compound Polymer layer 21 Polarizing layer 22, 23 Protective film 24 Functional layer 31, such as (lambda) / 4 board, antireflection film, Cold cathode tube 32 Reflective sheet 33 Light guide plate 34 Light control film 35 such as brightness enhancement film, diffusion film, etc. Liquid crystal cell 36 Lower polarizing plate 37 Upper polarizing plate 41 Polarizing layer 42 Transparent support 43 Orientation layer 44 Optical anisotropic layer 45 Polarizing plate protective film 46 Glass substrate for liquid crystal cell 47 Liquid crystal cell 48 Adhesive 51 Uniaxially stretched optical compensation sheet

Claims (20)

A transparent support; a polymer layer formed by applying and drying a solution having a solvent composition of 20% or more of water on the transparent support; and at least one liquid crystal compound and at least a surface of the polymer layer An optical compensation sheet having an optically anisotropic layer formed from a liquid crystal composition containing a kind of fluorine-containing horizontal alignment agent, wherein the optical retardation of the optically anisotropic layer is not 0 and in-plane The retardation value measured by injecting light of wavelength λ nm from the direction inclined + 40 ° with respect to the normal direction of the optical compensation sheet with the slow axis as the tilt axis (rotation axis), and the in-plane slow axis A difference in retardation value measured by making light having a wavelength λ nm incident from a direction inclined by −40 ° with respect to the normal direction of the optical compensation sheet as an inclination axis (rotation axis) is within ± 10%, and the high Molecular layer and optical anisotropy An optical compensation sheet in which the layer is chemically bonded and the fluorine-containing horizontal alignment agent is a compound represented by any one of the following general formulas (I) to (III);

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. An optically anisotropic layer formed of a transparent support, a polymer layer on the support, and a composition containing at least one liquid crystal compound and at least one fluorine-containing horizontal alignment agent on the surface of the polymer layer The front retardation (Re) of the optically anisotropic layer was not 0, and it was inclined + 40 ° with respect to the normal direction of the layer plane with the in-plane slow axis as the tilt axis (rotation axis) The retardation value measured by making light of wavelength λnm incident from the direction and the direction of wavelength λnm from the direction inclined −40 ° with respect to the normal direction of the layer plane with the in-plane slow axis as the tilt axis (rotation axis) Optical compensation wherein the difference in retardation value measured by incidence of light is within ± 10%, and the fluorine-containing horizontal alignment agent is a compound represented by any one of the following general formulas (I) to (III) Sheet;

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. 2. The first aspect according to claim 1, wherein the liquid crystal compound is a polymerizable discotic liquid crystal compound, and the optically anisotropic layer is a layer formed by a polymerization reaction of a reactive group of the polymerizable discotic liquid crystal compound. Alternatively, the optical compensation sheet according to any one of the second item. The liquid crystal compound is a discotic liquid crystal compound, and the optically anisotropic layer is a layer formed by irradiating polarized light after horizontally aligning the discotic liquid crystal compound. 4. The optical compensation sheet according to any one of items 3. The optical compensation sheet according to any one of claims 1 to 4, wherein the liquid crystal compound is a discotic liquid crystal compound having a triphenylene skeleton. The range according to claim 1 or 2, wherein the liquid crystal compound is a polymerizable rod-like liquid crystal compound, and the optically anisotropic layer is a layer formed by polymerizing a reactive group of the polymerizable rod-like liquid crystal compound. 3. The optical compensation sheet according to any one of items 2. The range according to claim 1, wherein the liquid crystal compound is a rod-like liquid crystal compound, and the optically anisotropic layer is a layer formed by irradiating polarized light after cholesteric alignment of the rod-like liquid crystal compound. 7. The optical compensation sheet according to item 6. The optical compensation sheet according to any one of claims 1 to 7, wherein the polymer layer is a layer containing a polymer having a reactive group in a side chain. 9. The optical compensation sheet according to claim 8, wherein the reactive group of the polymer having a reactive group in the side chain is a reactive group containing an ethylene group. The polymer layer according to any one of claims 1 to 9, wherein the polymer layer contains a polymer selected from a polyvinyl alcohol derivative, a poly (meth) acrylate derivative or a polysaccharide having a reactive group in a side chain. Optical compensation sheet. The optical compensation sheet according to any one of claims 1 to 10, wherein the transparent support is a support having at least one surface subjected to alkali saponification treatment. The optical compensation sheet according to any one of claims 1 to 11, wherein the transparent support contains a cellulose derivative or a cycloolefin derivative. A step of forming a polymer layer by applying and drying a solution having a solvent composition of 20% or more of water on a transparent support; and at least a discotic liquid crystal compound having a reactive group on the surface of the polymer layer Applying a liquid crystal composition comprising one and at least one fluorine-containing horizontal alignment agent to align the molecules of the discotic liquid crystal compound with an average tilt angle of less than 5 °; And forming the optically anisotropic layer in this order, and the fluorine-containing horizontal alignment agent is a compound represented by any one of the following general formulas (I) to (III): The method for producing an optical compensation sheet according to item 1 of the scope;

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. A step of coating and drying a solution comprising a solvent composition of 20% or more of water on a transparent support and forming a polymer layer; and at least one rod-like liquid crystal compound having a reactive group on the surface of the polymer layer And applying a liquid crystal composition containing at least one chiral agent and at least one fluorine-containing horizontal alignment agent to align the molecules of the rod-like liquid crystal compound with an average tilt angle of less than 5 °, and irradiating with polarized light The step of polymerizing molecules of the liquid crystal compound to form an optically anisotropic layer is performed in this order, and the fluorine-containing horizontal alignment agent is represented by any one of the following general formulas (I) to (III) A method for producing an optical compensation sheet according to claim 1, which is a compound;

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. The solution having a solvent composition of 20% or more of water contains a polymer having a reactive group in a side chain and polymerizes molecules of the liquid crystalline compound, and at the same time, at least a part of the polymer and the liquid crystal The method for producing an optical compensation sheet according to claim 13 or 14, wherein at least a part of molecules of the active compound react to form a chemical bond. Applying a liquid crystal composition containing a discotic liquid crystal compound having at least one polymerizable group and at least one fluorine-containing horizontal alignment agent to the surface of the polymer layer formed on the transparent support; The step of aligning the molecules of the tick liquid crystal compound with an average tilt angle of less than 5 ° and the step of forming an optically anisotropic layer by irradiating polarized light to polymerize the molecules of the discotic liquid crystal compound are performed in this order. The method for producing an optical compensation sheet according to claim 2, wherein the fluorine-containing horizontal alignment agent is a compound represented by any one of the following general formulas (I) to (III):

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. Applying a liquid crystal composition containing a rod-shaped liquid crystal compound having at least one polymerizable group and at least one fluorine-containing horizontal alignment agent to the surface of the polymer layer formed on the transparent support, the rod-shaped liquid crystal The step of cholesteric alignment of the compound molecules with an average tilt angle of less than 5 °, and the step of polymerizing the rod-like liquid crystal compound molecules by irradiating polarized light to form an optically anisotropic layer in this order, The method for producing an optical compensation sheet according to claim 2, wherein the fluorine-containing horizontal alignment agent is a compound represented by any one of the following general formulas (I) to (III):

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. X ¹ , X ² and X ^{3 each} represents a single bond or a divalent linking group;

In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom;

In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent containing a fluorine atom. A polarizing plate comprising at least one optical compensation sheet according to any one of claims 1 to 12 and a polarizer. A liquid crystal display device comprising the optical compensation sheet according to any one of claims 1 to 12 or the polarizing plate according to claim 18 . 20. The liquid crystal display device according to claim 19, wherein the display mode is a VA mode.

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